Merge pull request #1 from sigp/master

Merged from master project

Cargo.toml

@@ -1,7 +1,7 @@
 [workspace]
 members = [
 	"eth2/attester",
-	"eth2/block_producer",
+	"eth2/block_proposer",
 	"eth2/fork_choice",
 	"eth2/state_processing",
 	"eth2/types",
@@ -12,6 +12,7 @@ members = [
 	"eth2/utils/int_to_bytes",
 	"eth2/utils/slot_clock",
 	"eth2/utils/ssz",
+	"eth2/utils/ssz_derive",
 	"eth2/utils/swap_or_not_shuffle",
 	"eth2/utils/fisher_yates_shuffle",
 	"beacon_node",

beacon_node/beacon_chain/Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Paul Hauner <paul@paulhauner.com>"]
 edition = "2018"
 
 [dependencies]
-block_producer = { path = "../../eth2/block_producer" }
+block_proposer = { path = "../../eth2/block_proposer" }
 bls = { path = "../../eth2/utils/bls" }
 boolean-bitfield = { path = "../../eth2/utils/boolean-bitfield" }
 db = { path = "../db" }

beacon_node/beacon_chain/src/attestation_aggregator.rs

@@ -1,3 +1,4 @@
+use crate::cached_beacon_state::CachedBeaconState;
 use state_processing::validate_attestation_without_signature;
 use std::collections::{HashMap, HashSet};
 use types::{
@@ -76,12 +77,12 @@ impl AttestationAggregator {
     ///  - The signature is verified against that of the validator at `validator_index`.
     pub fn process_free_attestation(
         &mut self,
-        state: &BeaconState,
+        cached_state: &CachedBeaconState,
         free_attestation: &FreeAttestation,
         spec: &ChainSpec,
     ) -> Result<Outcome, BeaconStateError> {
         let (slot, shard, committee_index) = some_or_invalid!(
-            state.attestation_slot_and_shard_for_validator(
+            cached_state.attestation_slot_and_shard_for_validator(
                 free_attestation.validator_index as usize,
                 spec,
             )?,
@@ -104,7 +105,8 @@ impl AttestationAggregator {
         let signable_message = free_attestation.data.signable_message(PHASE_0_CUSTODY_BIT);
 
         let validator_record = some_or_invalid!(
-            state
+            cached_state
+                .state
                 .validator_registry
                 .get(free_attestation.validator_index as usize),
             Message::BadValidatorIndex

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -1,4 +1,5 @@
 use crate::attestation_aggregator::{AttestationAggregator, Outcome as AggregationOutcome};
+use crate::cached_beacon_state::CachedBeaconState;
 use crate::checkpoint::CheckPoint;
 use db::{
     stores::{BeaconBlockStore, BeaconStateStore},
@@ -69,6 +70,7 @@ pub struct BeaconChain<T: ClientDB + Sized, U: SlotClock, F: ForkChoice> {
     canonical_head: RwLock<CheckPoint>,
     finalized_head: RwLock<CheckPoint>,
     pub state: RwLock<BeaconState>,
+    pub cached_state: RwLock<CachedBeaconState>,
     pub spec: ChainSpec,
     pub fork_choice: RwLock<F>,
 }
@@ -107,6 +109,11 @@ where
         let block_root = genesis_block.canonical_root();
         block_store.put(&block_root, &ssz_encode(&genesis_block)[..])?;
 
+        let cached_state = RwLock::new(CachedBeaconState::from_beacon_state(
+            genesis_state.clone(),
+            spec.clone(),
+        )?);
+
         let finalized_head = RwLock::new(CheckPoint::new(
             genesis_block.clone(),
             block_root,
@@ -127,6 +134,7 @@ where
             slot_clock,
             attestation_aggregator,
             state: RwLock::new(genesis_state.clone()),
+            cached_state,
             finalized_head,
             canonical_head,
             spec,
@@ -253,6 +261,7 @@ where
     /// Information is read from the present `beacon_state` shuffling, so only information from the
     /// present and prior epoch is available.
     pub fn block_proposer(&self, slot: Slot) -> Result<usize, BeaconStateError> {
+        trace!("BeaconChain::block_proposer: slot: {}", slot);
         let index = self
             .state
             .read()
@@ -274,8 +283,12 @@ where
         &self,
         validator_index: usize,
     ) -> Result<Option<(Slot, u64)>, BeaconStateError> {
+        trace!(
+            "BeaconChain::validator_attestion_slot_and_shard: validator_index: {}",
+            validator_index
+        );
         if let Some((slot, shard, _committee)) = self
-            .state
+            .cached_state
             .read()
             .attestation_slot_and_shard_for_validator(validator_index, &self.spec)?
         {
@@ -287,6 +300,7 @@ where
 
     /// Produce an `AttestationData` that is valid for the present `slot` and given `shard`.
     pub fn produce_attestation_data(&self, shard: u64) -> Result<AttestationData, Error> {
+        trace!("BeaconChain::produce_attestation_data: shard: {}", shard);
         let justified_epoch = self.justified_epoch();
         let justified_block_root = *self
             .state
@@ -332,9 +346,7 @@ where
         let aggregation_outcome = self
             .attestation_aggregator
             .write()
-            .process_free_attestation(&self.state.read(), &free_attestation, &self.spec)?;
-        // TODO: Check this comment
-        //.map_err(|e| e.into())?;
+            .process_free_attestation(&self.cached_state.read(), &free_attestation, &self.spec)?;
 
         // return if the attestation is invalid
         if !aggregation_outcome.valid {
@@ -345,6 +357,7 @@ where
         self.fork_choice.write().add_attestation(
             free_attestation.validator_index,
             &free_attestation.data.beacon_block_root,
+            &self.spec,
         )?;
         Ok(aggregation_outcome)
     }
@@ -474,7 +487,9 @@ where
         self.state_store.put(&state_root, &ssz_encode(&state)[..])?;
 
         // run the fork_choice add_block logic
-        self.fork_choice.write().add_block(&block, &block_root)?;
+        self.fork_choice
+            .write()
+            .add_block(&block, &block_root, &self.spec)?;
 
         // If the parent block was the parent_block, automatically update the canonical head.
         //
@@ -489,6 +504,9 @@ where
             );
             // Update the local state variable.
             *self.state.write() = state.clone();
+            // Update the cached state variable.
+            *self.cached_state.write() =
+                CachedBeaconState::from_beacon_state(state.clone(), self.spec.clone())?;
         }
 
         Ok(BlockProcessingOutcome::ValidBlock(ValidBlock::Processed))
@@ -537,9 +555,15 @@ where
             },
         };
 
-        state
-            .per_block_processing_without_verifying_block_signature(&block, &self.spec)
-            .ok()?;
+        trace!("BeaconChain::produce_block: updating state for new block.",);
+
+        let result =
+            state.per_block_processing_without_verifying_block_signature(&block, &self.spec);
+        trace!(
+            "BeaconNode::produce_block: state processing result: {:?}",
+            result
+        );
+        result.ok()?;
 
         let state_root = state.canonical_root();
 
@@ -554,7 +578,10 @@ where
     pub fn fork_choice(&self) -> Result<(), Error> {
         let present_head = self.finalized_head().beacon_block_root;
 
-        let new_head = self.fork_choice.write().find_head(&present_head)?;
+        let new_head = self
+            .fork_choice
+            .write()
+            .find_head(&present_head, &self.spec)?;
 
         if new_head != present_head {
             let block = self

beacon_node/beacon_chain/src/cached_beacon_state.rs

@@ -0,0 +1,150 @@
+use log::{debug, trace};
+use std::collections::HashMap;
+use types::{beacon_state::BeaconStateError, BeaconState, ChainSpec, Epoch, Slot};
+
+pub const CACHE_PREVIOUS: bool = false;
+pub const CACHE_CURRENT: bool = true;
+pub const CACHE_NEXT: bool = false;
+
+pub type CrosslinkCommittees = Vec<(Vec<usize>, u64)>;
+pub type Shard = u64;
+pub type CommitteeIndex = u64;
+pub type AttestationDuty = (Slot, Shard, CommitteeIndex);
+pub type AttestationDutyMap = HashMap<u64, AttestationDuty>;
+
+// TODO: CachedBeaconState is presently duplicating `BeaconState` and `ChainSpec`. This is a
+// massive memory waste, switch them to references.
+
+pub struct CachedBeaconState {
+    pub state: BeaconState,
+    committees: Vec<Vec<CrosslinkCommittees>>,
+    attestation_duties: Vec<AttestationDutyMap>,
+    next_epoch: Epoch,
+    current_epoch: Epoch,
+    previous_epoch: Epoch,
+    spec: ChainSpec,
+}
+
+impl CachedBeaconState {
+    pub fn from_beacon_state(
+        state: BeaconState,
+        spec: ChainSpec,
+    ) -> Result<Self, BeaconStateError> {
+        let current_epoch = state.current_epoch(&spec);
+        let previous_epoch = if current_epoch == spec.genesis_epoch {
+            current_epoch
+        } else {
+            current_epoch.saturating_sub(1_u64)
+        };
+        let next_epoch = state.next_epoch(&spec);
+
+        let mut committees: Vec<Vec<CrosslinkCommittees>> = Vec::with_capacity(3);
+        let mut attestation_duties: Vec<AttestationDutyMap> = Vec::with_capacity(3);
+
+        if CACHE_PREVIOUS {
+            debug!("from_beacon_state: building previous epoch cache.");
+            let cache = build_epoch_cache(&state, previous_epoch, &spec)?;
+            committees.push(cache.committees);
+            attestation_duties.push(cache.attestation_duty_map);
+        } else {
+            committees.push(vec![]);
+            attestation_duties.push(HashMap::new());
+        }
+        if CACHE_CURRENT {
+            debug!("from_beacon_state: building current epoch cache.");
+            let cache = build_epoch_cache(&state, current_epoch, &spec)?;
+            committees.push(cache.committees);
+            attestation_duties.push(cache.attestation_duty_map);
+        } else {
+            committees.push(vec![]);
+            attestation_duties.push(HashMap::new());
+        }
+        if CACHE_NEXT {
+            debug!("from_beacon_state: building next epoch cache.");
+            let cache = build_epoch_cache(&state, next_epoch, &spec)?;
+            committees.push(cache.committees);
+            attestation_duties.push(cache.attestation_duty_map);
+        } else {
+            committees.push(vec![]);
+            attestation_duties.push(HashMap::new());
+        }
+
+        Ok(Self {
+            state,
+            committees,
+            attestation_duties,
+            next_epoch,
+            current_epoch,
+            previous_epoch,
+            spec,
+        })
+    }
+
+    fn slot_to_cache_index(&self, slot: Slot) -> Option<usize> {
+        trace!("slot_to_cache_index: cache lookup");
+        match slot.epoch(self.spec.epoch_length) {
+            epoch if (epoch == self.previous_epoch) & CACHE_PREVIOUS => Some(0),
+            epoch if (epoch == self.current_epoch) & CACHE_CURRENT => Some(1),
+            epoch if (epoch == self.next_epoch) & CACHE_NEXT => Some(2),
+            _ => None,
+        }
+    }
+
+    /// Returns the `slot`, `shard` and `committee_index` for which a validator must produce an
+    /// attestation.
+    ///
+    /// Cached method.
+    ///
+    /// Spec v0.2.0
+    pub fn attestation_slot_and_shard_for_validator(
+        &self,
+        validator_index: usize,
+        _spec: &ChainSpec,
+    ) -> Result<Option<(Slot, u64, u64)>, BeaconStateError> {
+        // Get the result for this epoch.
+        let cache_index = self
+            .slot_to_cache_index(self.state.slot)
+            .expect("Current epoch should always have a cache index.");
+
+        let duties = self.attestation_duties[cache_index]
+            .get(&(validator_index as u64))
+            .and_then(|tuple| Some(*tuple));
+
+        Ok(duties)
+    }
+}
+
+struct EpochCacheResult {
+    committees: Vec<CrosslinkCommittees>,
+    attestation_duty_map: AttestationDutyMap,
+}
+
+fn build_epoch_cache(
+    state: &BeaconState,
+    epoch: Epoch,
+    spec: &ChainSpec,
+) -> Result<EpochCacheResult, BeaconStateError> {
+    let mut epoch_committees: Vec<CrosslinkCommittees> =
+        Vec::with_capacity(spec.epoch_length as usize);
+    let mut attestation_duty_map: AttestationDutyMap = HashMap::new();
+
+    for slot in epoch.slot_iter(spec.epoch_length) {
+        let slot_committees = state.get_crosslink_committees_at_slot(slot, false, spec)?;
+
+        for (committee, shard) in slot_committees {
+            for (committee_index, validator_index) in committee.iter().enumerate() {
+                attestation_duty_map.insert(
+                    *validator_index as u64,
+                    (slot, shard, committee_index as u64),
+                );
+            }
+        }
+
+        epoch_committees.push(state.get_crosslink_committees_at_slot(slot, false, spec)?)
+    }
+
+    Ok(EpochCacheResult {
+        committees: epoch_committees,
+        attestation_duty_map,
+    })
+}

beacon_node/beacon_chain/src/lib.rs

@@ -1,7 +1,8 @@
 mod attestation_aggregator;
 mod beacon_chain;
+mod cached_beacon_state;
 mod checkpoint;
 
 pub use self::beacon_chain::{BeaconChain, Error};
 pub use self::checkpoint::CheckPoint;
-pub use fork_choice::{ForkChoice, ForkChoiceAlgorithms, ForkChoiceError};
+pub use fork_choice::{ForkChoice, ForkChoiceAlgorithm, ForkChoiceError};

beacon_node/beacon_chain/test_harness/Cargo.toml

@@ -14,7 +14,7 @@ criterion = "0.2"
 [dependencies]
 attester = { path = "../../../eth2/attester" }
 beacon_chain = { path = "../../beacon_chain" }
-block_producer = { path = "../../../eth2/block_producer" }
+block_proposer = { path = "../../../eth2/block_proposer" }
 bls = { path = "../../../eth2/utils/bls" }
 boolean-bitfield = { path = "../../../eth2/utils/boolean-bitfield" }
 db = { path = "../../db" }

beacon_node/beacon_chain/test_harness/src/beacon_chain_harness.rs

@@ -6,7 +6,7 @@ use db::{
     stores::{BeaconBlockStore, BeaconStateStore},
     MemoryDB,
 };
-use fork_choice::OptimisedLMDGhost;
+use fork_choice::BitwiseLMDGhost;
 use log::debug;
 use rayon::prelude::*;
 use slot_clock::TestingSlotClock;
@@ -28,7 +28,7 @@ use types::{
 /// is not useful for testing that multiple beacon nodes can reach consensus.
 pub struct BeaconChainHarness {
     pub db: Arc<MemoryDB>,
-    pub beacon_chain: Arc<BeaconChain<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>>,
+    pub beacon_chain: Arc<BeaconChain<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>>,
     pub block_store: Arc<BeaconBlockStore<MemoryDB>>,
     pub state_store: Arc<BeaconStateStore<MemoryDB>>,
     pub validators: Vec<ValidatorHarness>,
@@ -46,7 +46,7 @@ impl BeaconChainHarness {
         let state_store = Arc::new(BeaconStateStore::new(db.clone()));
         let genesis_time = 1_549_935_547; // 12th Feb 2018 (arbitrary value in the past).
         let slot_clock = TestingSlotClock::new(spec.genesis_slot.as_u64());
-        let fork_choice = OptimisedLMDGhost::new(block_store.clone(), state_store.clone());
+        let fork_choice = BitwiseLMDGhost::new(block_store.clone(), state_store.clone());
         let latest_eth1_data = Eth1Data {
             deposit_root: Hash256::zero(),
             block_hash: Hash256::zero(),
@@ -128,7 +128,18 @@ impl BeaconChainHarness {
     pub fn increment_beacon_chain_slot(&mut self) -> Slot {
         let slot = self.beacon_chain.present_slot() + 1;
 
-        debug!("Incrementing BeaconChain slot to {}.", slot);
+        let nth_slot = slot
+            - slot
+                .epoch(self.spec.epoch_length)
+                .start_slot(self.spec.epoch_length);
+        let nth_epoch = slot.epoch(self.spec.epoch_length) - self.spec.genesis_epoch;
+        debug!(
+            "Advancing BeaconChain to slot {}, epoch {} (epoch height: {}, slot {} in epoch.).",
+            slot,
+            slot.epoch(self.spec.epoch_length),
+            nth_epoch,
+            nth_slot
+        );
 
         self.beacon_chain.slot_clock.set_slot(slot.as_u64());
         self.beacon_chain.advance_state(slot).unwrap();
@@ -209,6 +220,7 @@ impl BeaconChainHarness {
         self.increment_beacon_chain_slot();
 
         // Produce a new block.
+        debug!("Producing block...");
         let block = self.produce_block();
         debug!("Submitting block for processing...");
         self.beacon_chain.process_block(block).unwrap();

beacon_node/beacon_chain/test_harness/src/validator_harness/direct_beacon_node.rs

@@ -3,7 +3,7 @@ use attester::{
     PublishOutcome as AttestationPublishOutcome,
 };
 use beacon_chain::BeaconChain;
-use block_producer::{
+use block_proposer::{
     BeaconNode as BeaconBlockNode, BeaconNodeError as BeaconBlockNodeError,
     PublishOutcome as BlockPublishOutcome,
 };

beacon_node/beacon_chain/test_harness/src/validator_harness/direct_duties.rs

@@ -2,7 +2,7 @@ use attester::{
     DutiesReader as AttesterDutiesReader, DutiesReaderError as AttesterDutiesReaderError,
 };
 use beacon_chain::BeaconChain;
-use block_producer::{
+use block_proposer::{
     DutiesReader as ProducerDutiesReader, DutiesReaderError as ProducerDutiesReaderError,
 };
 use db::ClientDB;

beacon_node/beacon_chain/test_harness/src/validator_harness/local_signer.rs

@@ -1,5 +1,5 @@
 use attester::Signer as AttesterSigner;
-use block_producer::Signer as BlockProposerSigner;
+use block_proposer::Signer as BlockProposerSigner;
 use std::sync::RwLock;
 use types::{Keypair, Signature};
 

beacon_node/beacon_chain/test_harness/src/validator_harness/mod.rs

@@ -5,12 +5,12 @@ mod local_signer;
 use attester::PollOutcome as AttestationPollOutcome;
 use attester::{Attester, Error as AttestationPollError};
 use beacon_chain::BeaconChain;
-use block_producer::PollOutcome as BlockPollOutcome;
-use block_producer::{BlockProducer, Error as BlockPollError};
+use block_proposer::PollOutcome as BlockPollOutcome;
+use block_proposer::{BlockProducer, Error as BlockPollError};
 use db::MemoryDB;
 use direct_beacon_node::DirectBeaconNode;
 use direct_duties::DirectDuties;
-use fork_choice::OptimisedLMDGhost;
+use fork_choice::BitwiseLMDGhost;
 use local_signer::LocalSigner;
 use slot_clock::TestingSlotClock;
 use std::sync::Arc;
@@ -36,20 +36,20 @@ pub enum AttestationProduceError {
 pub struct ValidatorHarness {
     pub block_producer: BlockProducer<
         TestingSlotClock,
-        DirectBeaconNode<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>,
-        DirectDuties<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>,
+        DirectBeaconNode<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>,
+        DirectDuties<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>,
         LocalSigner,
     >,
     pub attester: Attester<
         TestingSlotClock,
-        DirectBeaconNode<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>,
-        DirectDuties<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>,
+        DirectBeaconNode<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>,
+        DirectDuties<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>,
         LocalSigner,
     >,
     pub spec: Arc<ChainSpec>,
-    pub epoch_map: Arc<DirectDuties<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>>,
+    pub epoch_map: Arc<DirectDuties<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>>,
     pub keypair: Keypair,
-    pub beacon_node: Arc<DirectBeaconNode<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>>,
+    pub beacon_node: Arc<DirectBeaconNode<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>>,
     pub slot_clock: Arc<TestingSlotClock>,
     pub signer: Arc<LocalSigner>,
 }
@@ -61,7 +61,7 @@ impl ValidatorHarness {
     /// A `BlockProducer` and `Attester` is created..
     pub fn new(
         keypair: Keypair,
-        beacon_chain: Arc<BeaconChain<MemoryDB, TestingSlotClock, OptimisedLMDGhost<MemoryDB>>>,
+        beacon_chain: Arc<BeaconChain<MemoryDB, TestingSlotClock, BitwiseLMDGhost<MemoryDB>>>,
         spec: Arc<ChainSpec>,
     ) -> Self {
         let slot_clock = Arc::new(TestingSlotClock::new(spec.genesis_slot.as_u64()));

beacon_node/beacon_chain/test_harness/tests/chain.rs

@@ -1,19 +1,14 @@
 use env_logger::{Builder, Env};
 use log::debug;
 use test_harness::BeaconChainHarness;
-use types::{ChainSpec, Slot};
+use types::ChainSpec;
 
 #[test]
-#[ignore]
 fn it_can_build_on_genesis_block() {
-    let mut spec = ChainSpec::foundation();
-    spec.genesis_slot = Slot::new(spec.epoch_length * 8);
+    Builder::from_env(Env::default().default_filter_or("info")).init();
 
-    /*
-    spec.shard_count = spec.shard_count / 8;
-    spec.target_committee_size = spec.target_committee_size / 8;
-    */
-    let validator_count = 1000;
+    let spec = ChainSpec::few_validators();
+    let validator_count = 8;
 
     let mut harness = BeaconChainHarness::new(spec, validator_count as usize);
 
@@ -23,21 +18,22 @@ fn it_can_build_on_genesis_block() {
 #[test]
 #[ignore]
 fn it_can_produce_past_first_epoch_boundary() {
-    Builder::from_env(Env::default().default_filter_or("debug")).init();
+    Builder::from_env(Env::default().default_filter_or("info")).init();
 
-    let validator_count = 100;
+    let spec = ChainSpec::few_validators();
+    let validator_count = 8;
 
     debug!("Starting harness build...");
 
-    let mut harness = BeaconChainHarness::new(ChainSpec::foundation(), validator_count);
+    let mut harness = BeaconChainHarness::new(spec, validator_count);
 
     debug!("Harness built, tests starting..");
 
-    let blocks = harness.spec.epoch_length * 3 + 1;
+    let blocks = harness.spec.epoch_length * 2 + 1;
 
     for i in 0..blocks {
         harness.advance_chain_with_block();
-        debug!("Produced block {}/{}.", i, blocks);
+        debug!("Produced block {}/{}.", i + 1, blocks);
     }
     let dump = harness.chain_dump().expect("Chain dump failed.");
 

beacon_node/src/main.rs

@@ -14,7 +14,7 @@ use db::{
     stores::{BeaconBlockStore, BeaconStateStore},
     MemoryDB,
 };
-use fork_choice::optimised_lmd_ghost::OptimisedLMDGhost;
+use fork_choice::BitwiseLMDGhost;
 use slog::{error, info, o, Drain};
 use slot_clock::SystemTimeSlotClock;
 use std::sync::Arc;
@@ -81,7 +81,7 @@ fn main() {
     let slot_clock = SystemTimeSlotClock::new(genesis_time, spec.slot_duration)
         .expect("Unable to load SystemTimeSlotClock");
     // Choose the fork choice
-    let fork_choice = OptimisedLMDGhost::new(block_store.clone(), state_store.clone());
+    let fork_choice = BitwiseLMDGhost::new(block_store.clone(), state_store.clone());
 
     /*
      * Generate some random data to start a chain with.

eth2/block_proposer/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "block_producer"
+name = "block_proposer"
 version = "0.1.0"
 authors = ["Paul Hauner <paul@paulhauner.com>"]
 edition = "2018"

eth2/block_proposer/src/lib.rs

@@ -236,7 +236,7 @@ mod tests {
         epoch_map.map.insert(produce_epoch, produce_slot);
         let epoch_map = Arc::new(epoch_map);
 
-        let mut block_producer = BlockProducer::new(
+        let mut block_proposer = BlockProducer::new(
             spec.clone(),
             epoch_map.clone(),
             slot_clock.clone(),
@@ -251,28 +251,28 @@ mod tests {
         // One slot before production slot...
         slot_clock.set_slot(produce_slot.as_u64() - 1);
         assert_eq!(
-            block_producer.poll(),
+            block_proposer.poll(),
             Ok(PollOutcome::BlockProductionNotRequired(produce_slot - 1))
         );
 
         // On the produce slot...
         slot_clock.set_slot(produce_slot.as_u64());
         assert_eq!(
-            block_producer.poll(),
+            block_proposer.poll(),
             Ok(PollOutcome::BlockProduced(produce_slot.into()))
         );
 
         // Trying the same produce slot again...
         slot_clock.set_slot(produce_slot.as_u64());
         assert_eq!(
-            block_producer.poll(),
+            block_proposer.poll(),
             Ok(PollOutcome::SlotAlreadyProcessed(produce_slot))
         );
 
         // One slot after the produce slot...
         slot_clock.set_slot(produce_slot.as_u64() + 1);
         assert_eq!(
-            block_producer.poll(),
+            block_proposer.poll(),
             Ok(PollOutcome::BlockProductionNotRequired(produce_slot + 1))
         );
 
@@ -280,7 +280,7 @@ mod tests {
         let slot = (produce_epoch.as_u64() + 1) * spec.epoch_length;
         slot_clock.set_slot(slot);
         assert_eq!(
-            block_producer.poll(),
+            block_proposer.poll(),
             Ok(PollOutcome::ProducerDutiesUnknown(Slot::new(slot)))
         );
     }

eth2/fork_choice/Cargo.toml

@@ -9,10 +9,13 @@ db = { path = "../../beacon_node/db" }
 ssz = { path = "../utils/ssz" }
 types = { path = "../types" }
 fast-math = "0.1.1"
-byteorder = "1.3.1"
+log = "0.4.6"
+bit-vec = "0.5.0"
 
 [dev-dependencies]
+hex = "0.3.2"
 yaml-rust = "0.4.2"
 bls = { path = "../utils/bls" }
 slot_clock = { path = "../utils/slot_clock" }
 beacon_chain = { path = "../../beacon_node/beacon_chain" }
+env_logger = "0.6.0"

eth2/fork_choice/src/bitwise_lmd_ghost.rs

@@ -1,49 +1,25 @@
-// Copyright 2019 Sigma Prime Pty Ltd.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the "Software"),
-// to deal in the Software without restriction, including without limitation
-// the rights to use, copy, modify, merge, publish, distribute, sublicense,
-// and/or sell copies of the Software, and to permit persons to whom the
-// Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-extern crate byteorder;
+extern crate bit_vec;
 extern crate fast_math;
+
 use crate::{ForkChoice, ForkChoiceError};
-use byteorder::{BigEndian, ByteOrder};
+use bit_vec::BitVec;
 use db::{
     stores::{BeaconBlockStore, BeaconStateStore},
     ClientDB,
 };
 use fast_math::log2_raw;
+use log::{debug, trace};
 use std::collections::HashMap;
 use std::sync::Arc;
 use types::{
     readers::BeaconBlockReader, validator_registry::get_active_validator_indices, BeaconBlock,
-    Hash256, Slot, SlotHeight,
+    ChainSpec, Hash256, Slot, SlotHeight,
 };
 
 //TODO: Pruning - Children
 //TODO: Handle Syncing
 
-//TODO: Sort out global constants
-const GENESIS_SLOT: u64 = 0;
-const FORK_CHOICE_BALANCE_INCREMENT: u64 = 1e9 as u64;
-const MAX_DEPOSIT_AMOUNT: u64 = 32e9 as u64;
-const EPOCH_LENGTH: u64 = 64;
-
-/// The optimised LMD-GHOST fork choice rule.
+/// The optimised bitwise LMD-GHOST fork choice rule.
 /// NOTE: This uses u32 to represent difference between block heights. Thus this is only
 /// applicable for block height differences in the range of a u32.
 /// This can potentially be parallelized in some parts.
@@ -51,6 +27,13 @@ const EPOCH_LENGTH: u64 = 64;
 // the comparison. Log2_raw takes 2ns according to the documentation.
 #[inline]
 fn log2_int(x: u32) -> u32 {
+    if x == 0 {
+        return 0;
+    }
+    assert!(
+        x <= std::f32::MAX as u32,
+        "Height too large for fast log in bitwise fork choice"
+    );
     log2_raw(x as f32) as u32
 }
 
@@ -58,8 +41,8 @@ fn power_of_2_below(x: u32) -> u32 {
     2u32.pow(log2_int(x))
 }
 
-/// Stores the necessary data structures to run the optimised lmd ghost algorithm.
-pub struct OptimisedLMDGhost<T: ClientDB + Sized> {
+/// Stores the necessary data structures to run the optimised bitwise lmd ghost algorithm.
+pub struct BitwiseLMDGhost<T: ClientDB + Sized> {
     /// A cache of known ancestors at given heights for a specific block.
     //TODO: Consider FnvHashMap
     cache: HashMap<CacheKey<u32>, Hash256>,
@@ -78,7 +61,7 @@ pub struct OptimisedLMDGhost<T: ClientDB + Sized> {
     max_known_height: SlotHeight,
 }
 
-impl<T> OptimisedLMDGhost<T>
+impl<T> BitwiseLMDGhost<T>
 where
     T: ClientDB + Sized,
 {
@@ -86,7 +69,7 @@ where
         block_store: Arc<BeaconBlockStore<T>>,
         state_store: Arc<BeaconStateStore<T>>,
     ) -> Self {
-        OptimisedLMDGhost {
+        BitwiseLMDGhost {
             cache: HashMap::new(),
             ancestors: vec![HashMap::new(); 16],
             latest_attestation_targets: HashMap::new(),
@@ -103,6 +86,7 @@ where
         &self,
         state_root: &Hash256,
         block_slot: Slot,
+        spec: &ChainSpec,
     ) -> Result<HashMap<Hash256, u64>, ForkChoiceError> {
         // get latest votes
         // Note: Votes are weighted by min(balance, MAX_DEPOSIT_AMOUNT) //
@@ -117,25 +101,31 @@ where
 
         let active_validator_indices = get_active_validator_indices(
             &current_state.validator_registry[..],
-            block_slot.epoch(EPOCH_LENGTH),
+            block_slot.epoch(spec.epoch_length),
         );
 
         for index in active_validator_indices {
-            let balance =
-                std::cmp::min(current_state.validator_balances[index], MAX_DEPOSIT_AMOUNT)
-                    / FORK_CHOICE_BALANCE_INCREMENT;
+            let balance = std::cmp::min(
+                current_state.validator_balances[index],
+                spec.max_deposit_amount,
+            ) / spec.fork_choice_balance_increment;
             if balance > 0 {
                 if let Some(target) = self.latest_attestation_targets.get(&(index as u64)) {
                     *latest_votes.entry(*target).or_insert_with(|| 0) += balance;
                 }
             }
         }
-
+        trace!("Latest votes: {:?}", latest_votes);
         Ok(latest_votes)
     }
 
     /// Gets the ancestor at a given height `at_height` of a block specified by `block_hash`.
-    fn get_ancestor(&mut self, block_hash: Hash256, at_height: SlotHeight) -> Option<Hash256> {
+    fn get_ancestor(
+        &mut self,
+        block_hash: Hash256,
+        target_height: SlotHeight,
+        spec: &ChainSpec,
+    ) -> Option<Hash256> {
         // return None if we can't get the block from the db.
         let block_height = {
             let block_slot = self
@@ -145,32 +135,31 @@ where
                 .expect("Should have returned already if None")
                 .slot;
 
-            block_slot.height(Slot::from(GENESIS_SLOT))
+            block_slot.height(spec.genesis_slot)
         };
 
         // verify we haven't exceeded the block height
-        if at_height >= block_height {
-            if at_height > block_height {
+        if target_height >= block_height {
+            if target_height > block_height {
                 return None;
             } else {
                 return Some(block_hash);
             }
         }
         // check if the result is stored in our cache
-        let cache_key = CacheKey::new(&block_hash, at_height.as_u32());
+        let cache_key = CacheKey::new(&block_hash, target_height.as_u32());
         if let Some(ancestor) = self.cache.get(&cache_key) {
             return Some(*ancestor);
         }
 
         // not in the cache recursively search for ancestors using a log-lookup
-
         if let Some(ancestor) = {
             let ancestor_lookup = self.ancestors
-                [log2_int((block_height - at_height - 1u64).as_u32()) as usize]
+                [log2_int((block_height - target_height - 1u64).as_u32()) as usize]
                 .get(&block_hash)
                 //TODO: Panic if we can't lookup and fork choice fails
                 .expect("All blocks should be added to the ancestor log lookup table");
-            self.get_ancestor(*ancestor_lookup, at_height)
+            self.get_ancestor(*ancestor_lookup, target_height, &spec)
         } {
             // add the result to the cache
             self.cache.insert(cache_key, ancestor);
@@ -185,15 +174,17 @@ where
         &mut self,
         latest_votes: &HashMap<Hash256, u64>,
         block_height: SlotHeight,
+        spec: &ChainSpec,
     ) -> Option<Hash256> {
         // map of vote counts for every hash at this height
         let mut current_votes: HashMap<Hash256, u64> = HashMap::new();
         let mut total_vote_count = 0;
 
+        trace!("Clear winner at block height: {}", block_height);
         // loop through the latest votes and count all votes
         // these have already been weighted by balance
         for (hash, votes) in latest_votes.iter() {
-            if let Some(ancestor) = self.get_ancestor(*hash, block_height) {
+            if let Some(ancestor) = self.get_ancestor(*hash, block_height, spec) {
                 let current_vote_value = current_votes.get(&ancestor).unwrap_or_else(|| &0);
                 current_votes.insert(ancestor, current_vote_value + *votes);
                 total_vote_count += votes;
@@ -210,54 +201,62 @@ where
         None
     }
 
-    // Finds the best child, splitting children into a binary tree, based on their hashes
+    // Finds the best child, splitting children into a binary tree, based on their hashes (Bitwise
+    // LMD Ghost)
     fn choose_best_child(&self, votes: &HashMap<Hash256, u64>) -> Option<Hash256> {
-        let mut bitmask = 0;
-        for bit in (0..=255).rev() {
+        if votes.is_empty() {
+            return None;
+        }
+        let mut bitmask: BitVec = BitVec::new();
+        // loop through all bits
+        for bit in 0..=256 {
             let mut zero_votes = 0;
             let mut one_votes = 0;
-            let mut single_candidate = None;
+            let mut single_candidate = (None, false);
 
+            trace!("Child vote length: {}", votes.len());
             for (candidate, votes) in votes.iter() {
-                let candidate_uint = BigEndian::read_u32(candidate);
-                if candidate_uint >> (bit + 1) != bitmask {
+                let candidate_bit: BitVec = BitVec::from_bytes(&candidate);
+
+                // if the bitmasks don't match, exclude candidate
+                if !bitmask.iter().eq(candidate_bit.iter().take(bit)) {
+                    trace!(
+                        "Child: {} was removed in bit: {} with the bitmask: {:?}",
+                        candidate,
+                        bit,
+                        bitmask
+                    );
                     continue;
                 }
-                if (candidate_uint >> bit) % 2 == 0 {
+                if candidate_bit.get(bit) == Some(false) {
                     zero_votes += votes;
                 } else {
                     one_votes += votes;
                 }
 
-                if single_candidate.is_none() {
-                    single_candidate = Some(candidate);
+                if single_candidate.0.is_none() {
+                    single_candidate.0 = Some(candidate);
+                    single_candidate.1 = true;
                 } else {
-                    single_candidate = None;
+                    single_candidate.1 = false;
                 }
             }
-            bitmask = (bitmask * 2) + {
-                if one_votes > zero_votes {
-                    1
-                } else {
-                    0
+            bitmask.push(one_votes > zero_votes);
+            if single_candidate.1 {
+                return Some(*single_candidate.0.expect("Cannot reach this"));
             }
-            };
-            if let Some(candidate) = single_candidate {
-                return Some(*candidate);
-            }
-            //TODO Remove this during benchmark after testing
-            assert!(bit >= 1);
         }
         // should never reach here
         None
     }
 }
 
-impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
+impl<T: ClientDB + Sized> ForkChoice for BitwiseLMDGhost<T> {
     fn add_block(
         &mut self,
         block: &BeaconBlock,
         block_hash: &Hash256,
+        spec: &ChainSpec,
     ) -> Result<(), ForkChoiceError> {
         // get the height of the parent
         let parent_height = self
@@ -265,7 +264,7 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
             .get_deserialized(&block.parent_root)?
             .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(block.parent_root))?
             .slot()
-            .height(Slot::from(GENESIS_SLOT));
+            .height(spec.genesis_slot);
 
         let parent_hash = &block.parent_root;
 
@@ -295,22 +294,29 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
         &mut self,
         validator_index: u64,
         target_block_root: &Hash256,
+        spec: &ChainSpec,
     ) -> Result<(), ForkChoiceError> {
         // simply add the attestation to the latest_attestation_target if the block_height is
         // larger
+        trace!(
+            "Adding attestation of validator: {:?} for block: {}",
+            validator_index,
+            target_block_root
+        );
         let attestation_target = self
             .latest_attestation_targets
             .entry(validator_index)
             .or_insert_with(|| *target_block_root);
         // if we already have a value
         if attestation_target != target_block_root {
+            trace!("Old attestation found: {:?}", attestation_target);
             // get the height of the target block
             let block_height = self
                 .block_store
                 .get_deserialized(&target_block_root)?
                 .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*target_block_root))?
                 .slot()
-                .height(Slot::from(GENESIS_SLOT));
+                .height(spec.genesis_slot);
 
             // get the height of the past target block
             let past_block_height = self
@@ -318,9 +324,10 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
                 .get_deserialized(&attestation_target)?
                 .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*attestation_target))?
                 .slot()
-                .height(Slot::from(GENESIS_SLOT));
+                .height(spec.genesis_slot);
             // update the attestation only if the new target is higher
             if past_block_height < block_height {
+                trace!("Updating old attestation");
                 *attestation_target = *target_block_root;
             }
         }
@@ -328,25 +335,39 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
     }
 
     /// Perform lmd_ghost on the current chain to find the head.
-    fn find_head(&mut self, justified_block_start: &Hash256) -> Result<Hash256, ForkChoiceError> {
+    fn find_head(
+        &mut self,
+        justified_block_start: &Hash256,
+        spec: &ChainSpec,
+    ) -> Result<Hash256, ForkChoiceError> {
+        debug!(
+            "Starting optimised fork choice at block: {}",
+            justified_block_start
+        );
         let block = self
             .block_store
             .get_deserialized(&justified_block_start)?
             .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*justified_block_start))?;
 
         let block_slot = block.slot();
-        let block_height = block_slot.height(Slot::from(GENESIS_SLOT));
         let state_root = block.state_root();
+        let mut block_height = block_slot.height(spec.genesis_slot);
 
         let mut current_head = *justified_block_start;
 
-        let mut latest_votes = self.get_latest_votes(&state_root, block_slot)?;
+        let mut latest_votes = self.get_latest_votes(&state_root, block_slot, spec)?;
 
         // remove any votes that don't relate to our current head.
-        latest_votes.retain(|hash, _| self.get_ancestor(*hash, block_height) == Some(current_head));
+        latest_votes
+            .retain(|hash, _| self.get_ancestor(*hash, block_height, spec) == Some(current_head));
 
         // begin searching for the head
         loop {
+            debug!(
+                "Iteration for block: {} with vote length: {}",
+                current_head,
+                latest_votes.len()
+            );
             // if there are no children, we are done, return the current_head
             let children = match self.children.get(&current_head) {
                 Some(children) => children.clone(),
@@ -358,9 +379,11 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
             let mut step =
                 power_of_2_below(self.max_known_height.saturating_sub(block_height).as_u32()) / 2;
             while step > 0 {
+                trace!("Current Step: {}", step);
                 if let Some(clear_winner) = self.get_clear_winner(
                     &latest_votes,
                     block_height - (block_height % u64::from(step)) + u64::from(step),
+                    spec,
                 ) {
                     current_head = clear_winner;
                     break;
@@ -368,17 +391,23 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
                 step /= 2;
             }
             if step > 0 {
+                trace!("Found clear winner in log lookup");
             }
             // if our skip lookup failed and we only have one child, progress to that child
             else if children.len() == 1 {
                 current_head = children[0];
+                trace!(
+                    "Lookup failed, only one child, proceeding to child: {}",
+                    current_head
+                );
             }
             // we need to find the best child path to progress down.
             else {
+                trace!("Searching for best child");
                 let mut child_votes = HashMap::new();
                 for (voted_hash, vote) in latest_votes.iter() {
                     // if the latest votes correspond to a child
-                    if let Some(child) = self.get_ancestor(*voted_hash, block_height + 1) {
+                    if let Some(child) = self.get_ancestor(*voted_hash, block_height + 1, spec) {
                         // add up the votes for each child
                         *child_votes.entry(child).or_insert_with(|| 0) += vote;
                     }
@@ -387,22 +416,30 @@ impl<T: ClientDB + Sized> ForkChoice for OptimisedLMDGhost<T> {
                 current_head = self
                     .choose_best_child(&child_votes)
                     .ok_or(ForkChoiceError::CannotFindBestChild)?;
+                trace!("Best child found: {}", current_head);
             }
 
-            // No head was found, re-iterate
-
-            // update the block height for the next iteration
-            let block_height = self
+            // didn't find head yet, proceed to next iteration
+            // update block height
+            block_height = self
                 .block_store
                 .get_deserialized(&current_head)?
-                .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*justified_block_start))?
+                .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(current_head))?
                 .slot()
-                .height(Slot::from(GENESIS_SLOT));
-
+                .height(spec.genesis_slot);
             // prune the latest votes for votes that are not part of current chosen chain
             // more specifically, only keep votes that have head as an ancestor
-            latest_votes
-                .retain(|hash, _| self.get_ancestor(*hash, block_height) == Some(current_head));
+            for hash in latest_votes.keys() {
+                trace!(
+                    "Ancestor for vote: {} at height: {} is: {:?}",
+                    hash,
+                    block_height,
+                    self.get_ancestor(*hash, block_height, spec)
+                );
+            }
+            latest_votes.retain(|hash, _| {
+                self.get_ancestor(*hash, block_height, spec) == Some(current_head)
+            });
         }
     }
 }

eth2/fork_choice/src/lib.rs

@@ -1,57 +1,36 @@
-// Copyright 2019 Sigma Prime Pty Ltd.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the "Software"),
-// to deal in the Software without restriction, including without limitation
-// the rights to use, copy, modify, merge, publish, distribute, sublicense,
-// and/or sell copies of the Software, and to permit persons to whom the
-// Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
 //! This crate stores the various implementations of fork-choice rules that can be used for the
 //! beacon blockchain.
 //!
-//! There are four implementations. One is the naive longest chain rule (primarily for testing
-//! purposes). The other three are proposed implementations of the LMD-GHOST fork-choice rule with various forms of optimisation.
+//! There are three implementations. One is the naive longest chain rule (primarily for testing
+//! purposes). The other two are proposed implementations of the LMD-GHOST fork-choice rule with various forms of optimisation.
 //!
 //! The current implementations are:
 //! - [`longest-chain`]: Simplistic longest-chain fork choice - primarily for testing, **not for
 //! production**.
 //! - [`slow_lmd_ghost`]: This is a simple and very inefficient implementation given in the ethereum 2.0
 //! specifications (https://github.com/ethereum/eth2.0-specs/blob/v0.1/specs/core/0_beacon-chain.md#get_block_root).
-//! - [`optimised_lmd_ghost`]: This is an optimised version of the naive implementation as proposed
+//! - [`bitwise_lmd_ghost`]: This is an optimised version of bitwise LMD-GHOST as proposed
 //! by Vitalik. The reference implementation can be found at: https://github.com/ethereum/research/blob/master/ghost/ghost.py
-//! - [`protolambda_lmd_ghost`]: Another optimised version of LMD-GHOST designed by @protolambda.
-//! The go implementation can be found here: https://github.com/protolambda/lmd-ghost.
 //!
+//! [`longest-chain`]: struct.LongestChain.html
 //! [`slow_lmd_ghost`]: struct.SlowLmdGhost.html
-//! [`optimised_lmd_ghost`]: struct.OptimisedLmdGhost.html
-//! [`protolambda_lmd_ghost`]: struct.ProtolambdaLmdGhost.html
+//! [`bitwise_lmd_ghost`]: struct.OptimisedLmdGhost.html
 
 extern crate db;
 extern crate ssz;
 extern crate types;
 
+pub mod bitwise_lmd_ghost;
 pub mod longest_chain;
-pub mod optimised_lmd_ghost;
 pub mod slow_lmd_ghost;
 
 use db::stores::BeaconBlockAtSlotError;
 use db::DBError;
-use types::{BeaconBlock, Hash256};
+use types::{BeaconBlock, ChainSpec, Hash256};
 
+pub use bitwise_lmd_ghost::BitwiseLMDGhost;
 pub use longest_chain::LongestChain;
-pub use optimised_lmd_ghost::OptimisedLMDGhost;
+pub use slow_lmd_ghost::SlowLMDGhost;
 
 /// Defines the interface for Fork Choices. Each Fork choice will define their own data structures
 /// which can be built in block processing through the `add_block` and `add_attestation` functions.
@@ -63,6 +42,7 @@ pub trait ForkChoice: Send + Sync {
         &mut self,
         block: &BeaconBlock,
         block_hash: &Hash256,
+        spec: &ChainSpec,
     ) -> Result<(), ForkChoiceError>;
     /// Called when an attestation has been added. Allows generic attestation-level data structures to be built for a given fork choice.
     // This can be generalised to a full attestation if required later.
@@ -70,10 +50,15 @@ pub trait ForkChoice: Send + Sync {
         &mut self,
         validator_index: u64,
         target_block_hash: &Hash256,
+        spec: &ChainSpec,
     ) -> Result<(), ForkChoiceError>;
     /// The fork-choice algorithm to find the current canonical head of the chain.
     // TODO: Remove the justified_start_block parameter and make it internal
-    fn find_head(&mut self, justified_start_block: &Hash256) -> Result<Hash256, ForkChoiceError>;
+    fn find_head(
+        &mut self,
+        justified_start_block: &Hash256,
+        spec: &ChainSpec,
+    ) -> Result<Hash256, ForkChoiceError>;
 }
 
 /// Possible fork choice errors that can occur.
@@ -109,11 +94,11 @@ impl From<BeaconBlockAtSlotError> for ForkChoiceError {
 }
 
 /// Fork choice options that are currently implemented.
-pub enum ForkChoiceAlgorithms {
+pub enum ForkChoiceAlgorithm {
     /// Chooses the longest chain becomes the head. Not for production.
     LongestChain,
     /// A simple and highly inefficient implementation of LMD ghost.
     SlowLMDGhost,
-    /// An optimised version of LMD-GHOST by Vitalik.
-    OptimisedLMDGhost,
+    /// An optimised version of bitwise LMD-GHOST by Vitalik.
+    BitwiseLMDGhost,
 }

eth2/fork_choice/src/longest_chain.rs

@@ -1,7 +1,7 @@
 use crate::{ForkChoice, ForkChoiceError};
 use db::{stores::BeaconBlockStore, ClientDB};
 use std::sync::Arc;
-use types::{BeaconBlock, Hash256, Slot};
+use types::{BeaconBlock, ChainSpec, Hash256, Slot};
 
 pub struct LongestChain<T>
 where
@@ -30,6 +30,7 @@ impl<T: ClientDB + Sized> ForkChoice for LongestChain<T> {
         &mut self,
         block: &BeaconBlock,
         block_hash: &Hash256,
+        _: &ChainSpec,
     ) -> Result<(), ForkChoiceError> {
         // add the block hash to head_block_hashes removing the parent if it exists
         self.head_block_hashes
@@ -38,12 +39,17 @@ impl<T: ClientDB + Sized> ForkChoice for LongestChain<T> {
         Ok(())
     }
 
-    fn add_attestation(&mut self, _: u64, _: &Hash256) -> Result<(), ForkChoiceError> {
+    fn add_attestation(
+        &mut self,
+        _: u64,
+        _: &Hash256,
+        _: &ChainSpec,
+    ) -> Result<(), ForkChoiceError> {
         // do nothing
         Ok(())
     }
 
-    fn find_head(&mut self, _: &Hash256) -> Result<Hash256, ForkChoiceError> {
+    fn find_head(&mut self, _: &Hash256, _: &ChainSpec) -> Result<Hash256, ForkChoiceError> {
         let mut head_blocks: Vec<(usize, BeaconBlock)> = vec![];
         /*
          * Load all the head_block hashes from the DB as SszBeaconBlocks.

eth2/fork_choice/src/slow_lmd_ghost.rs

@@ -1,23 +1,3 @@
-// Copyright 2019 Sigma Prime Pty Ltd.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the "Software"),
-// to deal in the Software without restriction, including without limitation
-// the rights to use, copy, modify, merge, publish, distribute, sublicense,
-// and/or sell copies of the Software, and to permit persons to whom the
-// Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
-// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
 extern crate db;
 
 use crate::{ForkChoice, ForkChoiceError};
@@ -25,21 +5,16 @@ use db::{
     stores::{BeaconBlockStore, BeaconStateStore},
     ClientDB,
 };
+use log::{debug, trace};
 use std::collections::HashMap;
 use std::sync::Arc;
 use types::{
     readers::BeaconBlockReader, validator_registry::get_active_validator_indices, BeaconBlock,
-    Hash256, Slot,
+    ChainSpec, Hash256, Slot,
 };
 
 //TODO: Pruning and syncing
 
-//TODO: Sort out global constants
-const GENESIS_SLOT: u64 = 0;
-const FORK_CHOICE_BALANCE_INCREMENT: u64 = 1e9 as u64;
-const MAX_DEPOSIT_AMOUNT: u64 = 32e9 as u64;
-const EPOCH_LENGTH: u64 = 64;
-
 pub struct SlowLMDGhost<T: ClientDB + Sized> {
     /// The latest attestation targets as a map of validator index to block hash.
     //TODO: Could this be a fixed size vec
@@ -56,12 +31,15 @@ impl<T> SlowLMDGhost<T>
 where
     T: ClientDB + Sized,
 {
-    pub fn new(block_store: BeaconBlockStore<T>, state_store: BeaconStateStore<T>) -> Self {
+    pub fn new(
+        block_store: Arc<BeaconBlockStore<T>>,
+        state_store: Arc<BeaconStateStore<T>>,
+    ) -> Self {
         SlowLMDGhost {
             latest_attestation_targets: HashMap::new(),
             children: HashMap::new(),
-            block_store: Arc::new(block_store),
-            state_store: Arc::new(state_store),
+            block_store,
+            state_store,
         }
     }
 
@@ -71,6 +49,7 @@ where
         &self,
         state_root: &Hash256,
         block_slot: Slot,
+        spec: &ChainSpec,
     ) -> Result<HashMap<Hash256, u64>, ForkChoiceError> {
         // get latest votes
         // Note: Votes are weighted by min(balance, MAX_DEPOSIT_AMOUNT) //
@@ -84,21 +63,22 @@ where
             .ok_or_else(|| ForkChoiceError::MissingBeaconState(*state_root))?;
 
         let active_validator_indices = get_active_validator_indices(
-            &current_state.validator_registry,
-            block_slot.epoch(EPOCH_LENGTH),
+            &current_state.validator_registry[..],
+            block_slot.epoch(spec.epoch_length),
         );
 
         for index in active_validator_indices {
-            let balance =
-                std::cmp::min(current_state.validator_balances[index], MAX_DEPOSIT_AMOUNT)
-                    / FORK_CHOICE_BALANCE_INCREMENT;
+            let balance = std::cmp::min(
+                current_state.validator_balances[index],
+                spec.max_deposit_amount,
+            ) / spec.fork_choice_balance_increment;
             if balance > 0 {
                 if let Some(target) = self.latest_attestation_targets.get(&(index as u64)) {
                     *latest_votes.entry(*target).or_insert_with(|| 0) += balance;
                 }
             }
         }
-
+        trace!("Latest votes: {:?}", latest_votes);
         Ok(latest_votes)
     }
 
@@ -117,12 +97,12 @@ where
             .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*block_root))?
             .slot();
 
-        for (target_hash, votes) in latest_votes.iter() {
+        for (vote_hash, votes) in latest_votes.iter() {
             let (root_at_slot, _) = self
                 .block_store
-                .block_at_slot(&block_root, block_slot)?
-                .ok_or(ForkChoiceError::MissingBeaconBlock(*block_root))?;
-            if root_at_slot == *target_hash {
+                .block_at_slot(&vote_hash, block_slot)?
+                .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*block_root))?;
+            if root_at_slot == *block_root {
                 count += votes;
             }
         }
@@ -136,6 +116,7 @@ impl<T: ClientDB + Sized> ForkChoice for SlowLMDGhost<T> {
         &mut self,
         block: &BeaconBlock,
         block_hash: &Hash256,
+        _: &ChainSpec,
     ) -> Result<(), ForkChoiceError> {
         // build the children hashmap
         // add the new block to the children of parent
@@ -153,22 +134,29 @@ impl<T: ClientDB + Sized> ForkChoice for SlowLMDGhost<T> {
         &mut self,
         validator_index: u64,
         target_block_root: &Hash256,
+        spec: &ChainSpec,
     ) -> Result<(), ForkChoiceError> {
         // simply add the attestation to the latest_attestation_target if the block_height is
         // larger
+        trace!(
+            "Adding attestation of validator: {:?} for block: {}",
+            validator_index,
+            target_block_root
+        );
         let attestation_target = self
             .latest_attestation_targets
             .entry(validator_index)
             .or_insert_with(|| *target_block_root);
         // if we already have a value
         if attestation_target != target_block_root {
+            trace!("Old attestation found: {:?}", attestation_target);
             // get the height of the target block
             let block_height = self
                 .block_store
                 .get_deserialized(&target_block_root)?
                 .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*target_block_root))?
                 .slot()
-                .height(Slot::from(GENESIS_SLOT));
+                .height(spec.genesis_slot);
 
             // get the height of the past target block
             let past_block_height = self
@@ -176,9 +164,10 @@ impl<T: ClientDB + Sized> ForkChoice for SlowLMDGhost<T> {
                 .get_deserialized(&attestation_target)?
                 .ok_or_else(|| ForkChoiceError::MissingBeaconBlock(*attestation_target))?
                 .slot()
-                .height(Slot::from(GENESIS_SLOT));
+                .height(spec.genesis_slot);
             // update the attestation only if the new target is higher
             if past_block_height < block_height {
+                trace!("Updating old attestation");
                 *attestation_target = *target_block_root;
             }
         }
@@ -186,7 +175,12 @@ impl<T: ClientDB + Sized> ForkChoice for SlowLMDGhost<T> {
     }
 
     /// A very inefficient implementation of LMD ghost.
-    fn find_head(&mut self, justified_block_start: &Hash256) -> Result<Hash256, ForkChoiceError> {
+    fn find_head(
+        &mut self,
+        justified_block_start: &Hash256,
+        spec: &ChainSpec,
+    ) -> Result<Hash256, ForkChoiceError> {
+        debug!("Running LMD Ghost Fork-choice rule");
         let start = self
             .block_store
             .get_deserialized(&justified_block_start)?
@@ -194,12 +188,12 @@ impl<T: ClientDB + Sized> ForkChoice for SlowLMDGhost<T> {
 
         let start_state_root = start.state_root();
 
-        let latest_votes = self.get_latest_votes(&start_state_root, start.slot())?;
+        let latest_votes = self.get_latest_votes(&start_state_root, start.slot(), spec)?;
 
-        let mut head_hash = Hash256::zero();
+        let mut head_hash = *justified_block_start;
 
         loop {
-            let mut head_vote_count = 0;
+            debug!("Iteration for block: {}", head_hash);
 
             let children = match self.children.get(&head_hash) {
                 Some(children) => children,
@@ -207,8 +201,18 @@ impl<T: ClientDB + Sized> ForkChoice for SlowLMDGhost<T> {
                 None => break,
             };
 
+            // if we only have one child, use it
+            if children.len() == 1 {
+                trace!("Single child found.");
+                head_hash = children[0];
+                continue;
+            }
+            trace!("Children found: {:?}", children);
+
+            let mut head_vote_count = 0;
             for child_hash in children {
                 let vote_count = self.get_vote_count(&latest_votes, &child_hash)?;
+                trace!("Vote count for child: {} is: {}", child_hash, vote_count);
 
                 if vote_count > head_vote_count {
                     head_hash = *child_hash;

eth2/fork_choice/tests/bitwise_lmd_ghost_test_vectors.yaml

@@ -0,0 +1,37 @@
+title: Fork-choice Tests
+summary: A collection of abstract fork-choice tests for bitwise lmd ghost.
+test_suite: Fork-Choice
+
+test_cases:
+- blocks:
+    - id: 'b0'
+      parent: 'b0'
+    - id: 'b1'
+      parent: 'b0'
+    - id: 'b2'
+      parent: 'b1'
+    - id: 'b3'
+      parent: 'b1'
+  weights:
+    - b0: 0
+    - b1: 0
+    - b2: 5
+    - b3: 10
+  heads:
+    - id: 'b3'
+# bitwise LMD ghost example. bitwise GHOST gives b2
+- blocks:
+    - id: 'b0'
+      parent: 'b0'
+    - id: 'b1'
+      parent: 'b0'
+    - id: 'b2'
+      parent: 'b0'
+    - id: 'b3'
+      parent: 'b0'
+  weights:
+    - b1: 5
+    - b2: 4
+    - b3: 3
+  heads:
+    - id: 'b2'

eth2/fork_choice/tests/lmd_ghost_test_vectors.yaml

@@ -0,0 +1,37 @@
+title: Fork-choice Tests
+summary: A collection of abstract fork-choice tests for lmd ghost.
+test_suite: Fork-Choice
+
+test_cases:
+- blocks:
+    - id: 'b0'
+      parent: 'b0'
+    - id: 'b1'
+      parent: 'b0'
+    - id: 'b2'
+      parent: 'b1'
+    - id: 'b3'
+      parent: 'b1'
+  weights:
+    - b0: 0
+    - b1: 0
+    - b2: 5
+    - b3: 10
+  heads:
+    - id: 'b3'
+# bitwise LMD ghost example. GHOST gives b1
+- blocks:
+    - id: 'b0'
+      parent: 'b0'
+    - id: 'b1'
+      parent: 'b0'
+    - id: 'b2'
+      parent: 'b0'
+    - id: 'b3'
+      parent: 'b0'
+  weights:
+    - b1: 5
+    - b2: 4
+    - b3: 3
+  heads:
+    - id: 'b1'

eth2/fork_choice/tests/longest_chain_test_vectors.yaml

@@ -0,0 +1,51 @@
+title: Fork-choice Tests
+summary: A collection of abstract fork-choice tests to verify the longest chain fork-choice rule.
+test_suite: Fork-Choice
+
+test_cases:
+- blocks:
+    - id: 'b0'
+      parent: 'b0'
+    - id: 'b1'
+      parent: 'b0'
+    - id: 'b2'
+      parent: 'b1'
+    - id: 'b3'
+      parent: 'b1'
+    - id: 'b4'
+      parent: 'b3'
+  weights:
+    - b0: 0
+    - b1: 0
+    - b2: 10
+    - b3: 1
+  heads:
+    - id: 'b4'
+- blocks:
+    - id: 'b0'
+      parent: 'b0'
+    - id: 'b1'
+      parent: 'b0'
+    - id: 'b2'
+      parent: 'b1'
+    - id: 'b3'
+      parent: 'b2'
+    - id: 'b4'
+      parent: 'b3'
+    - id: 'b5'
+      parent: 'b0'
+    - id: 'b6'
+      parent: 'b5'
+    - id: 'b7'
+      parent: 'b6'
+    - id: 'b8'
+      parent: 'b7'
+    - id: 'b9'
+      parent: 'b8'
+  weights:
+    - b0: 5
+    - b1: 20
+    - b2: 10
+    - b3: 10
+  heads:
+    - id: 'b9'

eth2/fork_choice/tests/tests.rs

@@ -0,0 +1,281 @@
+// Tests the available fork-choice algorithms
+
+extern crate beacon_chain;
+extern crate bls;
+extern crate db;
+//extern crate env_logger; // for debugging
+extern crate fork_choice;
+extern crate hex;
+extern crate log;
+extern crate slot_clock;
+extern crate types;
+extern crate yaml_rust;
+
+pub use beacon_chain::BeaconChain;
+use bls::{PublicKey, Signature};
+use db::stores::{BeaconBlockStore, BeaconStateStore};
+use db::MemoryDB;
+//use env_logger::{Builder, Env};
+use fork_choice::{BitwiseLMDGhost, ForkChoice, ForkChoiceAlgorithm, LongestChain, SlowLMDGhost};
+use ssz::ssz_encode;
+use std::collections::HashMap;
+use std::sync::Arc;
+use std::{fs::File, io::prelude::*, path::PathBuf};
+use types::{
+    BeaconBlock, BeaconBlockBody, BeaconState, ChainSpec, Epoch, Eth1Data, Hash256, Slot, Validator,
+};
+use yaml_rust::yaml;
+
+// Note: We Assume the block Id's are hex-encoded.
+
+#[test]
+fn test_bitwise_lmd_ghost() {
+    // set up logging
+    //Builder::from_env(Env::default().default_filter_or("trace")).init();
+
+    test_yaml_vectors(
+        ForkChoiceAlgorithm::BitwiseLMDGhost,
+        "tests/bitwise_lmd_ghost_test_vectors.yaml",
+        100,
+    );
+}
+
+#[test]
+fn test_slow_lmd_ghost() {
+    test_yaml_vectors(
+        ForkChoiceAlgorithm::SlowLMDGhost,
+        "tests/lmd_ghost_test_vectors.yaml",
+        100,
+    );
+}
+
+#[test]
+fn test_longest_chain() {
+    test_yaml_vectors(
+        ForkChoiceAlgorithm::LongestChain,
+        "tests/longest_chain_test_vectors.yaml",
+        100,
+    );
+}
+
+// run a generic test over given YAML test vectors
+fn test_yaml_vectors(
+    fork_choice_algo: ForkChoiceAlgorithm,
+    yaml_file_path: &str,
+    emulated_validators: usize, // the number of validators used to give weights.
+) {
+    // load test cases from yaml
+    let test_cases = load_test_cases_from_yaml(yaml_file_path);
+
+    // default vars
+    let spec = ChainSpec::foundation();
+    let zero_hash = Hash256::zero();
+    let eth1_data = Eth1Data {
+        deposit_root: zero_hash.clone(),
+        block_hash: zero_hash.clone(),
+    };
+    let randao_reveal = Signature::empty_signature();
+    let signature = Signature::empty_signature();
+    let body = BeaconBlockBody {
+        proposer_slashings: vec![],
+        attester_slashings: vec![],
+        attestations: vec![],
+        deposits: vec![],
+        exits: vec![],
+    };
+
+    // process the tests
+    for test_case in test_cases {
+        // setup a fresh test
+        let (mut fork_choice, block_store, state_root) =
+            setup_inital_state(&fork_choice_algo, emulated_validators);
+
+        // keep a hashmap of block_id's to block_hashes (random hashes to abstract block_id)
+        //let mut block_id_map: HashMap<String, Hash256> = HashMap::new();
+        // keep a list of hash to slot
+        let mut block_slot: HashMap<Hash256, Slot> = HashMap::new();
+        // assume the block tree is given to us in order.
+        let mut genesis_hash = None;
+        for block in test_case["blocks"].clone().into_vec().unwrap() {
+            let block_id = block["id"].as_str().unwrap().to_string();
+            let parent_id = block["parent"].as_str().unwrap().to_string();
+
+            // default params for genesis
+            let block_hash = id_to_hash(&block_id);
+            let mut slot = spec.genesis_slot;
+            let parent_root = id_to_hash(&parent_id);
+
+            // set the slot and parent based off the YAML. Start with genesis;
+            // if not the genesis, update slot
+            if parent_id != block_id {
+                // find parent slot
+                slot = *(block_slot
+                    .get(&parent_root)
+                    .expect("Parent should have a slot number"))
+                    + 1;
+            } else {
+                genesis_hash = Some(block_hash);
+            }
+
+            // update slot mapping
+            block_slot.insert(block_hash, slot);
+
+            // build the BeaconBlock
+            let beacon_block = BeaconBlock {
+                slot,
+                parent_root,
+                state_root: state_root.clone(),
+                randao_reveal: randao_reveal.clone(),
+                eth1_data: eth1_data.clone(),
+                signature: signature.clone(),
+                body: body.clone(),
+            };
+
+            // Store the block.
+            block_store
+                .put(&block_hash, &ssz_encode(&beacon_block)[..])
+                .unwrap();
+
+            // run add block for fork choice if not genesis
+            if parent_id != block_id {
+                fork_choice
+                    .add_block(&beacon_block, &block_hash, &spec)
+                    .unwrap();
+            }
+        }
+
+        // add the weights (attestations)
+        let mut current_validator = 0;
+        for id_map in test_case["weights"].clone().into_vec().unwrap() {
+            // get the block id and weights
+            for (map_id, map_weight) in id_map.as_hash().unwrap().iter() {
+                let id = map_id.as_str().unwrap();
+                let block_root = id_to_hash(&id.to_string());
+                let weight = map_weight.as_i64().unwrap();
+                // we assume a validator has a value 1 and add an attestation for to achieve the
+                // correct weight
+                for _ in 0..weight {
+                    assert!(
+                        current_validator <= emulated_validators,
+                        "Not enough validators to emulate weights"
+                    );
+                    fork_choice
+                        .add_attestation(current_validator as u64, &block_root, &spec)
+                        .unwrap();
+                    current_validator += 1;
+                }
+            }
+        }
+
+        // everything is set up, run the fork choice, using genesis as the head
+        let head = fork_choice
+            .find_head(&genesis_hash.unwrap(), &spec)
+            .unwrap();
+
+        // compare the result to the expected test
+        let success = test_case["heads"]
+            .clone()
+            .into_vec()
+            .unwrap()
+            .iter()
+            .find(|heads| id_to_hash(&heads["id"].as_str().unwrap().to_string()) == head)
+            .is_some();
+
+        println!("Head found: {}", head);
+        assert!(success, "Did not find one of the possible heads");
+    }
+}
+
+// loads the test_cases from the supplied yaml file
+fn load_test_cases_from_yaml(file_path: &str) -> Vec<yaml_rust::Yaml> {
+    // load the yaml
+    let mut file = {
+        let mut file_path_buf = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+        file_path_buf.push(file_path);
+        File::open(file_path_buf).unwrap()
+    };
+    let mut yaml_str = String::new();
+    file.read_to_string(&mut yaml_str).unwrap();
+    let docs = yaml::YamlLoader::load_from_str(&yaml_str).unwrap();
+    let doc = &docs[0];
+    doc["test_cases"].as_vec().unwrap().clone()
+}
+
+// initialise a single validator and state. All blocks will reference this state root.
+fn setup_inital_state(
+    fork_choice_algo: &ForkChoiceAlgorithm,
+    no_validators: usize,
+) -> (Box<ForkChoice>, Arc<BeaconBlockStore<MemoryDB>>, Hash256) {
+    let zero_hash = Hash256::zero();
+
+    let db = Arc::new(MemoryDB::open());
+    let block_store = Arc::new(BeaconBlockStore::new(db.clone()));
+    let state_store = Arc::new(BeaconStateStore::new(db.clone()));
+
+    // the fork choice instantiation
+    let fork_choice: Box<ForkChoice> = match fork_choice_algo {
+        ForkChoiceAlgorithm::BitwiseLMDGhost => Box::new(BitwiseLMDGhost::new(
+            block_store.clone(),
+            state_store.clone(),
+        )),
+        ForkChoiceAlgorithm::SlowLMDGhost => {
+            Box::new(SlowLMDGhost::new(block_store.clone(), state_store.clone()))
+        }
+        ForkChoiceAlgorithm::LongestChain => Box::new(LongestChain::new(block_store.clone())),
+    };
+
+    // misc vars for setting up the state
+    let genesis_time = 1_550_381_159;
+
+    let latest_eth1_data = Eth1Data {
+        deposit_root: zero_hash.clone(),
+        block_hash: zero_hash.clone(),
+    };
+
+    let initial_validator_deposits = vec![];
+    let spec = ChainSpec::foundation();
+
+    // create the state
+    let mut state = BeaconState::genesis(
+        genesis_time,
+        initial_validator_deposits,
+        latest_eth1_data,
+        &spec,
+    )
+    .unwrap();
+
+    let default_validator = Validator {
+        pubkey: PublicKey::default(),
+        withdrawal_credentials: zero_hash,
+        activation_epoch: Epoch::from(0u64),
+        exit_epoch: spec.far_future_epoch,
+        withdrawal_epoch: spec.far_future_epoch,
+        penalized_epoch: spec.far_future_epoch,
+        status_flags: None,
+    };
+    // activate the validators
+    for _ in 0..no_validators {
+        state.validator_registry.push(default_validator.clone());
+        state.validator_balances.push(32_000_000_000);
+    }
+
+    let state_root = state.canonical_root();
+    state_store
+        .put(&state_root, &ssz_encode(&state)[..])
+        .unwrap();
+
+    // return initialised vars
+    (fork_choice, block_store, state_root)
+}
+
+// convert a block_id into a Hash256 -- assume input is hex encoded;
+fn id_to_hash(id: &String) -> Hash256 {
+    let bytes = hex::decode(id).expect("Block ID should be hex");
+
+    let len = std::cmp::min(bytes.len(), 32);
+    let mut fixed_bytes = [0u8; 32];
+    for (index, byte) in bytes.iter().take(32).enumerate() {
+        fixed_bytes[32 - len + index] = *byte;
+    }
+    Hash256::from(fixed_bytes)
+}

eth2/state_processing/src/block_processable.rs

@@ -1,7 +1,7 @@
 use crate::SlotProcessingError;
 use hashing::hash;
 use int_to_bytes::int_to_bytes32;
-use log::debug;
+use log::{debug, trace};
 use ssz::{ssz_encode, TreeHash};
 use types::{
     beacon_state::{AttestationParticipantsError, BeaconStateError},
@@ -219,6 +219,8 @@ fn per_block_processing_signature_optional(
         Error::MaxAttestationsExceeded
     );
 
+    debug!("Verifying {} attestations.", block.body.attestations.len());
+
     for attestation in &block.body.attestations {
         validate_attestation(&state, attestation, spec)?;
 
@@ -231,11 +233,6 @@ fn per_block_processing_signature_optional(
         state.latest_attestations.push(pending_attestation);
     }
 
-    debug!(
-        "{} attestations verified & processed.",
-        block.body.attestations.len()
-    );
-
     /*
      * Deposits
      */
@@ -312,6 +309,10 @@ fn validate_attestation_signature_optional(
     spec: &ChainSpec,
     verify_signature: bool,
 ) -> Result<(), AttestationValidationError> {
+    trace!(
+        "validate_attestation_signature_optional: attestation epoch: {}",
+        attestation.data.slot.epoch(spec.epoch_length)
+    );
     ensure!(
         attestation.data.slot + spec.min_attestation_inclusion_delay <= state.slot,
         AttestationValidationError::IncludedTooEarly

eth2/state_processing/src/epoch_processable.rs

@@ -144,8 +144,10 @@ impl EpochProcessable for BeaconState {
 
         let previous_epoch_attester_indices =
             self.get_attestation_participants_union(&previous_epoch_attestations[..], spec)?;
-        let previous_total_balance =
-            self.get_total_balance(&previous_epoch_attester_indices[..], spec);
+        let previous_total_balance = self.get_total_balance(
+            &get_active_validator_indices(&self.validator_registry, previous_epoch),
+            spec,
+        );
 
         /*
          * Validators targetting the previous justified slot
@@ -315,6 +317,11 @@ impl EpochProcessable for BeaconState {
 
         // for slot in self.slot.saturating_sub(2 * spec.epoch_length)..self.slot {
         for slot in self.previous_epoch(spec).slot_iter(spec.epoch_length) {
+            trace!(
+                "Finding winning root for slot: {} (epoch: {})",
+                slot,
+                slot.epoch(spec.epoch_length)
+            );
             let crosslink_committees_at_slot =
                 self.get_crosslink_committees_at_slot(slot, false, spec)?;
 
@@ -352,7 +359,8 @@ impl EpochProcessable for BeaconState {
         /*
          * Rewards and Penalities
          */
-        let base_reward_quotient = previous_total_balance.integer_sqrt();
+        let base_reward_quotient =
+            previous_total_balance.integer_sqrt() / spec.base_reward_quotient;
         if base_reward_quotient == 0 {
             return Err(Error::BaseRewardQuotientIsZero);
         }
@@ -539,6 +547,12 @@ impl EpochProcessable for BeaconState {
          */
         self.previous_calculation_epoch = self.current_calculation_epoch;
         self.previous_epoch_start_shard = self.current_epoch_start_shard;
+
+        debug!(
+            "setting previous_epoch_seed to : {}",
+            self.current_epoch_seed
+        );
+
         self.previous_epoch_seed = self.current_epoch_seed;
 
         let should_update_validator_registy = if self.finalized_epoch
@@ -553,6 +567,7 @@ impl EpochProcessable for BeaconState {
         };
 
         if should_update_validator_registy {
+            trace!("updating validator registry.");
             self.update_validator_registry(spec);
 
             self.current_calculation_epoch = next_epoch;
@@ -561,6 +576,7 @@ impl EpochProcessable for BeaconState {
                 % spec.shard_count;
             self.current_epoch_seed = self.generate_seed(self.current_calculation_epoch, spec)?
         } else {
+            trace!("not updating validator registry.");
             let epochs_since_last_registry_update =
                 current_epoch - self.validator_registry_update_epoch;
             if (epochs_since_last_registry_update > 1)

eth2/types/Cargo.toml

@@ -18,7 +18,8 @@ serde_derive = "1.0"
 serde_json = "1.0"
 slog = "^2.2.3"
 ssz = { path = "../utils/ssz" }
-fisher_yates_shuffle = { path = "../utils/fisher_yates_shuffle" }
+ssz_derive = { path = "../utils/ssz_derive" }
+swap_or_not_shuffle = { path = "../utils/swap_or_not_shuffle" }
 
 [dev-dependencies]
 env_logger = "0.6.0"

eth2/types/src/attestation.rs

@@ -2,9 +2,10 @@ use super::{AggregatePublicKey, AggregateSignature, AttestationData, Bitfield, H
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, Clone, PartialEq, Serialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode)]
 pub struct Attestation {
     pub aggregation_bitfield: Bitfield,
     pub data: AttestationData,
@@ -33,39 +34,13 @@ impl Attestation {
     }
 }
 
-impl Encodable for Attestation {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.aggregation_bitfield);
-        s.append(&self.data);
-        s.append(&self.custody_bitfield);
-        s.append(&self.aggregate_signature);
-    }
-}
-
-impl Decodable for Attestation {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (aggregation_bitfield, i) = Bitfield::ssz_decode(bytes, i)?;
-        let (data, i) = AttestationData::ssz_decode(bytes, i)?;
-        let (custody_bitfield, i) = Bitfield::ssz_decode(bytes, i)?;
-        let (aggregate_signature, i) = AggregateSignature::ssz_decode(bytes, i)?;
-
-        let attestation_record = Self {
-            aggregation_bitfield,
-            data,
-            custody_bitfield,
-            aggregate_signature,
-        };
-        Ok((attestation_record, i))
-    }
-}
-
 impl TreeHash for Attestation {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.aggregation_bitfield.hash_tree_root());
-        result.append(&mut self.data.hash_tree_root());
-        result.append(&mut self.custody_bitfield.hash_tree_root());
-        result.append(&mut self.aggregate_signature.hash_tree_root());
+        result.append(&mut self.aggregation_bitfield.hash_tree_root_internal());
+        result.append(&mut self.data.hash_tree_root_internal());
+        result.append(&mut self.custody_bitfield.hash_tree_root_internal());
+        result.append(&mut self.aggregate_signature.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -85,7 +60,7 @@ impl<T: RngCore> TestRandom<T> for Attestation {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -99,11 +74,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Attestation::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/attestation_data.rs

@@ -2,7 +2,8 @@ use crate::test_utils::TestRandom;
 use crate::{AttestationDataAndCustodyBit, Crosslink, Epoch, Hash256, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
 pub const SSZ_ATTESTION_DATA_LENGTH: usize = {
     8 +             // slot
@@ -15,7 +16,7 @@ pub const SSZ_ATTESTION_DATA_LENGTH: usize = {
     32 // justified_block_root
 };
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize, Hash)]
+#[derive(Debug, Clone, PartialEq, Default, Serialize, Hash, Encode, Decode)]
 pub struct AttestationData {
     pub slot: Slot,
     pub shard: u64,
@@ -43,55 +44,17 @@ impl AttestationData {
     }
 }
 
-impl Encodable for AttestationData {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.slot);
-        s.append(&self.shard);
-        s.append(&self.beacon_block_root);
-        s.append(&self.epoch_boundary_root);
-        s.append(&self.shard_block_root);
-        s.append(&self.latest_crosslink);
-        s.append(&self.justified_epoch);
-        s.append(&self.justified_block_root);
-    }
-}
-
-impl Decodable for AttestationData {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (slot, i) = <_>::ssz_decode(bytes, i)?;
-        let (shard, i) = <_>::ssz_decode(bytes, i)?;
-        let (beacon_block_root, i) = <_>::ssz_decode(bytes, i)?;
-        let (epoch_boundary_root, i) = <_>::ssz_decode(bytes, i)?;
-        let (shard_block_root, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_crosslink, i) = <_>::ssz_decode(bytes, i)?;
-        let (justified_epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (justified_block_root, i) = <_>::ssz_decode(bytes, i)?;
-
-        let attestation_data = AttestationData {
-            slot,
-            shard,
-            beacon_block_root,
-            epoch_boundary_root,
-            shard_block_root,
-            latest_crosslink,
-            justified_epoch,
-            justified_block_root,
-        };
-        Ok((attestation_data, i))
-    }
-}
-
 impl TreeHash for AttestationData {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slot.hash_tree_root());
-        result.append(&mut self.shard.hash_tree_root());
-        result.append(&mut self.beacon_block_root.hash_tree_root());
-        result.append(&mut self.epoch_boundary_root.hash_tree_root());
-        result.append(&mut self.shard_block_root.hash_tree_root());
-        result.append(&mut self.latest_crosslink.hash_tree_root());
-        result.append(&mut self.justified_epoch.hash_tree_root());
-        result.append(&mut self.justified_block_root.hash_tree_root());
+        result.append(&mut self.slot.hash_tree_root_internal());
+        result.append(&mut self.shard.hash_tree_root_internal());
+        result.append(&mut self.beacon_block_root.hash_tree_root_internal());
+        result.append(&mut self.epoch_boundary_root.hash_tree_root_internal());
+        result.append(&mut self.shard_block_root.hash_tree_root_internal());
+        result.append(&mut self.latest_crosslink.hash_tree_root_internal());
+        result.append(&mut self.justified_epoch.hash_tree_root_internal());
+        result.append(&mut self.justified_block_root.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -115,7 +78,7 @@ impl<T: RngCore> TestRandom<T> for AttestationData {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -129,11 +92,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = AttestationData::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/attestation_data_and_custody_bit.rs

@@ -2,38 +2,21 @@ use super::AttestationData;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::TreeHash;
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize)]
+#[derive(Debug, Clone, PartialEq, Default, Serialize, Encode, Decode)]
 pub struct AttestationDataAndCustodyBit {
     pub data: AttestationData,
     pub custody_bit: bool,
 }
 
-impl Encodable for AttestationDataAndCustodyBit {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.data);
-        // TODO: deal with bools
-    }
-}
-
-impl Decodable for AttestationDataAndCustodyBit {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (data, i) = <_>::ssz_decode(bytes, i)?;
-        let custody_bit = false;
-
-        let attestation_data_and_custody_bit = AttestationDataAndCustodyBit { data, custody_bit };
-
-        Ok((attestation_data_and_custody_bit, i))
-    }
-}
-
 impl TreeHash for AttestationDataAndCustodyBit {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.data.hash_tree_root());
+        result.append(&mut self.data.hash_tree_root_internal());
         // TODO: add bool ssz
-        // result.append(custody_bit.hash_tree_root());
+        // result.append(custody_bit.hash_tree_root_internal());
         ssz::hash(&result)
     }
 }
@@ -52,7 +35,7 @@ impl<T: RngCore> TestRandom<T> for AttestationDataAndCustodyBit {
 mod test {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -68,11 +51,11 @@ mod test {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = AttestationDataAndCustodyBit::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/attester_slashing.rs

@@ -1,41 +1,20 @@
 use crate::{test_utils::TestRandom, SlashableAttestation};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct AttesterSlashing {
     pub slashable_attestation_1: SlashableAttestation,
     pub slashable_attestation_2: SlashableAttestation,
 }
 
-impl Encodable for AttesterSlashing {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.slashable_attestation_1);
-        s.append(&self.slashable_attestation_2);
-    }
-}
-
-impl Decodable for AttesterSlashing {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (slashable_attestation_1, i) = <_>::ssz_decode(bytes, i)?;
-        let (slashable_attestation_2, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            AttesterSlashing {
-                slashable_attestation_1,
-                slashable_attestation_2,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for AttesterSlashing {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slashable_attestation_1.hash_tree_root());
-        result.append(&mut self.slashable_attestation_2.hash_tree_root());
+        result.append(&mut self.slashable_attestation_1.hash_tree_root_internal());
+        result.append(&mut self.slashable_attestation_2.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -53,7 +32,7 @@ impl<T: RngCore> TestRandom<T> for AttesterSlashing {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -67,11 +46,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = AttesterSlashing::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/beacon_block.rs

@@ -3,9 +3,10 @@ use crate::{BeaconBlockBody, ChainSpec, Eth1Data, Hash256, ProposalSignedData, S
 use bls::Signature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct BeaconBlock {
     pub slot: Slot,
     pub parent_root: Hash256,
@@ -59,53 +60,16 @@ impl BeaconBlock {
     }
 }
 
-impl Encodable for BeaconBlock {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.slot);
-        s.append(&self.parent_root);
-        s.append(&self.state_root);
-        s.append(&self.randao_reveal);
-        s.append(&self.eth1_data);
-        s.append(&self.signature);
-        s.append(&self.body);
-    }
-}
-
-impl Decodable for BeaconBlock {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (slot, i) = <_>::ssz_decode(bytes, i)?;
-        let (parent_root, i) = <_>::ssz_decode(bytes, i)?;
-        let (state_root, i) = <_>::ssz_decode(bytes, i)?;
-        let (randao_reveal, i) = <_>::ssz_decode(bytes, i)?;
-        let (eth1_data, i) = <_>::ssz_decode(bytes, i)?;
-        let (signature, i) = <_>::ssz_decode(bytes, i)?;
-        let (body, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                slot,
-                parent_root,
-                state_root,
-                randao_reveal,
-                eth1_data,
-                signature,
-                body,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for BeaconBlock {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slot.hash_tree_root());
-        result.append(&mut self.parent_root.hash_tree_root());
-        result.append(&mut self.state_root.hash_tree_root());
-        result.append(&mut self.randao_reveal.hash_tree_root());
-        result.append(&mut self.eth1_data.hash_tree_root());
-        result.append(&mut self.signature.hash_tree_root());
-        result.append(&mut self.body.hash_tree_root());
+        result.append(&mut self.slot.hash_tree_root_internal());
+        result.append(&mut self.parent_root.hash_tree_root_internal());
+        result.append(&mut self.state_root.hash_tree_root_internal());
+        result.append(&mut self.randao_reveal.hash_tree_root_internal());
+        result.append(&mut self.eth1_data.hash_tree_root_internal());
+        result.append(&mut self.signature.hash_tree_root_internal());
+        result.append(&mut self.body.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -128,7 +92,7 @@ impl<T: RngCore> TestRandom<T> for BeaconBlock {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -142,11 +106,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = BeaconBlock::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/beacon_block_body.rs

@@ -2,9 +2,10 @@ use super::{Attestation, AttesterSlashing, Deposit, Exit, ProposerSlashing};
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Default, Serialize)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode)]
 pub struct BeaconBlockBody {
     pub proposer_slashings: Vec<ProposerSlashing>,
     pub attester_slashings: Vec<AttesterSlashing>,
@@ -13,45 +14,14 @@ pub struct BeaconBlockBody {
     pub exits: Vec<Exit>,
 }
 
-impl Encodable for BeaconBlockBody {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append_vec(&self.proposer_slashings);
-        s.append_vec(&self.attester_slashings);
-        s.append_vec(&self.attestations);
-        s.append_vec(&self.deposits);
-        s.append_vec(&self.exits);
-    }
-}
-
-impl Decodable for BeaconBlockBody {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (proposer_slashings, i) = <_>::ssz_decode(bytes, i)?;
-        let (attester_slashings, i) = <_>::ssz_decode(bytes, i)?;
-        let (attestations, i) = <_>::ssz_decode(bytes, i)?;
-        let (deposits, i) = <_>::ssz_decode(bytes, i)?;
-        let (exits, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                proposer_slashings,
-                attester_slashings,
-                attestations,
-                deposits,
-                exits,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for BeaconBlockBody {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.proposer_slashings.hash_tree_root());
-        result.append(&mut self.attester_slashings.hash_tree_root());
-        result.append(&mut self.attestations.hash_tree_root());
-        result.append(&mut self.deposits.hash_tree_root());
-        result.append(&mut self.exits.hash_tree_root());
+        result.append(&mut self.proposer_slashings.hash_tree_root_internal());
+        result.append(&mut self.attester_slashings.hash_tree_root_internal());
+        result.append(&mut self.attestations.hash_tree_root_internal());
+        result.append(&mut self.deposits.hash_tree_root_internal());
+        result.append(&mut self.exits.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -72,7 +42,7 @@ impl<T: RngCore> TestRandom<T> for BeaconBlockBody {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -86,11 +56,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = BeaconBlockBody::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/beacon_state.rs

@@ -5,15 +5,20 @@ use crate::{
     PendingAttestation, PublicKey, Signature, Slot, Validator,
 };
 use bls::verify_proof_of_possession;
-use fisher_yates_shuffle::shuffle;
 use honey_badger_split::SplitExt;
+use log::trace;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
+use swap_or_not_shuffle::get_permutated_index;
+
+mod tests;
 
 #[derive(Debug, PartialEq)]
 pub enum BeaconStateError {
     EpochOutOfBounds,
+    UnableToShuffle,
     InsufficientRandaoMixes,
     InsufficientValidators,
     InsufficientBlockRoots,
@@ -47,7 +52,7 @@ macro_rules! safe_sub_assign {
     };
 }
 
-#[derive(Debug, PartialEq, Clone, Default, Serialize)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode)]
 pub struct BeaconState {
     // Misc
     pub slot: Slot,
@@ -201,7 +206,12 @@ impl BeaconState {
     ///
     /// Spec v0.2.0
     pub fn previous_epoch(&self, spec: &ChainSpec) -> Epoch {
-        self.current_epoch(spec).saturating_sub(1_u64)
+        let current_epoch = self.current_epoch(&spec);
+        if current_epoch == spec.genesis_epoch {
+            current_epoch
+        } else {
+            current_epoch - 1
+        }
     }
 
     /// The epoch following `self.current_epoch()`.
@@ -249,23 +259,50 @@ impl BeaconState {
     /// committee is itself a list of validator indices.
     ///
     /// Spec v0.1
-    pub fn get_shuffling(&self, seed: Hash256, epoch: Epoch, spec: &ChainSpec) -> Vec<Vec<usize>> {
+    pub fn get_shuffling(
+        &self,
+        seed: Hash256,
+        epoch: Epoch,
+        spec: &ChainSpec,
+    ) -> Option<Vec<Vec<usize>>> {
         let active_validator_indices =
             get_active_validator_indices(&self.validator_registry, epoch);
 
+        if active_validator_indices.is_empty() {
+            return None;
+        }
+
+        trace!(
+            "get_shuffling: active_validator_indices.len() == {}",
+            active_validator_indices.len()
+        );
+
         let committees_per_epoch =
             self.get_epoch_committee_count(active_validator_indices.len(), spec);
 
-        // TODO: check that Hash256::from(u64) matches 'int_to_bytes32'.
-        let seed = seed ^ Hash256::from(epoch.as_u64());
-        // TODO: fix `expect` assert.
-        let shuffled_active_validator_indices =
-            shuffle(&seed, active_validator_indices).expect("Max validator count exceed!");
+        trace!(
+            "get_shuffling: active_validator_indices.len() == {}, committees_per_epoch: {}",
+            active_validator_indices.len(),
+            committees_per_epoch
+        );
 
+        let mut shuffled_active_validator_indices = vec![0; active_validator_indices.len()];
+        for &i in &active_validator_indices {
+            let shuffled_i = get_permutated_index(
+                i,
+                active_validator_indices.len(),
+                &seed[..],
+                spec.shuffle_round_count,
+            )?;
+            shuffled_active_validator_indices[i] = active_validator_indices[shuffled_i]
+        }
+
+        Some(
             shuffled_active_validator_indices
                 .honey_badger_split(committees_per_epoch as usize)
                 .map(|slice: &[usize]| slice.to_vec())
-            .collect()
+                .collect(),
+        )
     }
 
     /// Return the number of committees in the previous epoch.
@@ -303,9 +340,17 @@ impl BeaconState {
             + 1;
         let latest_index_root = current_epoch + spec.entry_exit_delay;
 
+        trace!(
+            "get_active_index_root: epoch: {}, earliest: {}, latest: {}",
+            epoch,
+            earliest_index_root,
+            latest_index_root
+        );
+
         if (epoch >= earliest_index_root) & (epoch <= latest_index_root) {
             Some(self.latest_index_roots[epoch.as_usize() % spec.latest_index_roots_length])
         } else {
+            trace!("get_active_index_root: epoch out of range.");
             None
         }
     }
@@ -350,29 +395,28 @@ impl BeaconState {
     ) -> Result<Vec<(Vec<usize>, u64)>, BeaconStateError> {
         let epoch = slot.epoch(spec.epoch_length);
         let current_epoch = self.current_epoch(spec);
-        let previous_epoch = if current_epoch == spec.genesis_epoch {
-            current_epoch
-        } else {
-            current_epoch.saturating_sub(1_u64)
-        };
+        let previous_epoch = self.previous_epoch(spec);
         let next_epoch = self.next_epoch(spec);
 
         let (committees_per_epoch, seed, shuffling_epoch, shuffling_start_shard) =
-            if epoch == previous_epoch {
-                (
-                    self.get_previous_epoch_committee_count(spec),
-                    self.previous_epoch_seed,
-                    self.previous_calculation_epoch,
-                    self.previous_epoch_start_shard,
-                )
-            } else if epoch == current_epoch {
+            if epoch == current_epoch {
+                trace!("get_crosslink_committees_at_slot: current_epoch");
                 (
                     self.get_current_epoch_committee_count(spec),
                     self.current_epoch_seed,
                     self.current_calculation_epoch,
                     self.current_epoch_start_shard,
                 )
+            } else if epoch == previous_epoch {
+                trace!("get_crosslink_committees_at_slot: previous_epoch");
+                (
+                    self.get_previous_epoch_committee_count(spec),
+                    self.previous_epoch_seed,
+                    self.previous_calculation_epoch,
+                    self.previous_epoch_start_shard,
+                )
             } else if epoch == next_epoch {
+                trace!("get_crosslink_committees_at_slot: next_epoch");
                 let current_committees_per_epoch = self.get_current_epoch_committee_count(spec);
                 let epochs_since_last_registry_update =
                     current_epoch - self.validator_registry_update_epoch;
@@ -401,12 +445,21 @@ impl BeaconState {
                 return Err(BeaconStateError::EpochOutOfBounds);
             };
 
-        let shuffling = self.get_shuffling(seed, shuffling_epoch, spec);
+        let shuffling = self
+            .get_shuffling(seed, shuffling_epoch, spec)
+            .ok_or_else(|| BeaconStateError::UnableToShuffle)?;
         let offset = slot.as_u64() % spec.epoch_length;
         let committees_per_slot = committees_per_epoch / spec.epoch_length;
         let slot_start_shard =
             (shuffling_start_shard + committees_per_slot * offset) % spec.shard_count;
 
+        trace!(
+            "get_crosslink_committees_at_slot: committees_per_slot: {}, slot_start_shard: {}, seed: {}",
+            committees_per_slot,
+            slot_start_shard,
+            seed
+        );
+
         let mut crosslinks_at_slot = vec![];
         for i in 0..committees_per_slot {
             let tuple = (
@@ -458,6 +511,11 @@ impl BeaconState {
         spec: &ChainSpec,
     ) -> Result<usize, BeaconStateError> {
         let committees = self.get_crosslink_committees_at_slot(slot, false, spec)?;
+        trace!(
+            "get_beacon_proposer_index: slot: {}, committees_count: {}",
+            slot,
+            committees.len()
+        );
         committees
             .first()
             .ok_or(BeaconStateError::InsufficientValidators)
@@ -910,125 +968,38 @@ impl From<AttestationParticipantsError> for InclusionError {
     }
 }
 
-impl Encodable for BeaconState {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.slot);
-        s.append(&self.genesis_time);
-        s.append(&self.fork);
-        s.append(&self.validator_registry);
-        s.append(&self.validator_balances);
-        s.append(&self.validator_registry_update_epoch);
-        s.append(&self.latest_randao_mixes);
-        s.append(&self.previous_epoch_start_shard);
-        s.append(&self.current_epoch_start_shard);
-        s.append(&self.previous_calculation_epoch);
-        s.append(&self.current_calculation_epoch);
-        s.append(&self.previous_epoch_seed);
-        s.append(&self.current_epoch_seed);
-        s.append(&self.previous_justified_epoch);
-        s.append(&self.justified_epoch);
-        s.append(&self.justification_bitfield);
-        s.append(&self.finalized_epoch);
-        s.append(&self.latest_crosslinks);
-        s.append(&self.latest_block_roots);
-        s.append(&self.latest_index_roots);
-        s.append(&self.latest_penalized_balances);
-        s.append(&self.latest_attestations);
-        s.append(&self.batched_block_roots);
-        s.append(&self.latest_eth1_data);
-        s.append(&self.eth1_data_votes);
-    }
-}
-
-impl Decodable for BeaconState {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (slot, i) = <_>::ssz_decode(bytes, i)?;
-        let (genesis_time, i) = <_>::ssz_decode(bytes, i)?;
-        let (fork, i) = <_>::ssz_decode(bytes, i)?;
-        let (validator_registry, i) = <_>::ssz_decode(bytes, i)?;
-        let (validator_balances, i) = <_>::ssz_decode(bytes, i)?;
-        let (validator_registry_update_epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_randao_mixes, i) = <_>::ssz_decode(bytes, i)?;
-        let (previous_epoch_start_shard, i) = <_>::ssz_decode(bytes, i)?;
-        let (current_epoch_start_shard, i) = <_>::ssz_decode(bytes, i)?;
-        let (previous_calculation_epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (current_calculation_epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (previous_epoch_seed, i) = <_>::ssz_decode(bytes, i)?;
-        let (current_epoch_seed, i) = <_>::ssz_decode(bytes, i)?;
-        let (previous_justified_epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (justified_epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (justification_bitfield, i) = <_>::ssz_decode(bytes, i)?;
-        let (finalized_epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_crosslinks, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_block_roots, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_index_roots, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_penalized_balances, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_attestations, i) = <_>::ssz_decode(bytes, i)?;
-        let (batched_block_roots, i) = <_>::ssz_decode(bytes, i)?;
-        let (latest_eth1_data, i) = <_>::ssz_decode(bytes, i)?;
-        let (eth1_data_votes, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                slot,
-                genesis_time,
-                fork,
-                validator_registry,
-                validator_balances,
-                validator_registry_update_epoch,
-                latest_randao_mixes,
-                previous_epoch_start_shard,
-                current_epoch_start_shard,
-                previous_calculation_epoch,
-                current_calculation_epoch,
-                previous_epoch_seed,
-                current_epoch_seed,
-                previous_justified_epoch,
-                justified_epoch,
-                justification_bitfield,
-                finalized_epoch,
-                latest_crosslinks,
-                latest_block_roots,
-                latest_index_roots,
-                latest_penalized_balances,
-                latest_attestations,
-                batched_block_roots,
-                latest_eth1_data,
-                eth1_data_votes,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for BeaconState {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slot.hash_tree_root());
-        result.append(&mut self.genesis_time.hash_tree_root());
-        result.append(&mut self.fork.hash_tree_root());
-        result.append(&mut self.validator_registry.hash_tree_root());
-        result.append(&mut self.validator_balances.hash_tree_root());
-        result.append(&mut self.validator_registry_update_epoch.hash_tree_root());
-        result.append(&mut self.latest_randao_mixes.hash_tree_root());
-        result.append(&mut self.previous_epoch_start_shard.hash_tree_root());
-        result.append(&mut self.current_epoch_start_shard.hash_tree_root());
-        result.append(&mut self.previous_calculation_epoch.hash_tree_root());
-        result.append(&mut self.current_calculation_epoch.hash_tree_root());
-        result.append(&mut self.previous_epoch_seed.hash_tree_root());
-        result.append(&mut self.current_epoch_seed.hash_tree_root());
-        result.append(&mut self.previous_justified_epoch.hash_tree_root());
-        result.append(&mut self.justified_epoch.hash_tree_root());
-        result.append(&mut self.justification_bitfield.hash_tree_root());
-        result.append(&mut self.finalized_epoch.hash_tree_root());
-        result.append(&mut self.latest_crosslinks.hash_tree_root());
-        result.append(&mut self.latest_block_roots.hash_tree_root());
-        result.append(&mut self.latest_index_roots.hash_tree_root());
-        result.append(&mut self.latest_penalized_balances.hash_tree_root());
-        result.append(&mut self.latest_attestations.hash_tree_root());
-        result.append(&mut self.batched_block_roots.hash_tree_root());
-        result.append(&mut self.latest_eth1_data.hash_tree_root());
-        result.append(&mut self.eth1_data_votes.hash_tree_root());
+        result.append(&mut self.slot.hash_tree_root_internal());
+        result.append(&mut self.genesis_time.hash_tree_root_internal());
+        result.append(&mut self.fork.hash_tree_root_internal());
+        result.append(&mut self.validator_registry.hash_tree_root_internal());
+        result.append(&mut self.validator_balances.hash_tree_root_internal());
+        result.append(
+            &mut self
+                .validator_registry_update_epoch
+                .hash_tree_root_internal(),
+        );
+        result.append(&mut self.latest_randao_mixes.hash_tree_root_internal());
+        result.append(&mut self.previous_epoch_start_shard.hash_tree_root_internal());
+        result.append(&mut self.current_epoch_start_shard.hash_tree_root_internal());
+        result.append(&mut self.previous_calculation_epoch.hash_tree_root_internal());
+        result.append(&mut self.current_calculation_epoch.hash_tree_root_internal());
+        result.append(&mut self.previous_epoch_seed.hash_tree_root_internal());
+        result.append(&mut self.current_epoch_seed.hash_tree_root_internal());
+        result.append(&mut self.previous_justified_epoch.hash_tree_root_internal());
+        result.append(&mut self.justified_epoch.hash_tree_root_internal());
+        result.append(&mut self.justification_bitfield.hash_tree_root_internal());
+        result.append(&mut self.finalized_epoch.hash_tree_root_internal());
+        result.append(&mut self.latest_crosslinks.hash_tree_root_internal());
+        result.append(&mut self.latest_block_roots.hash_tree_root_internal());
+        result.append(&mut self.latest_index_roots.hash_tree_root_internal());
+        result.append(&mut self.latest_penalized_balances.hash_tree_root_internal());
+        result.append(&mut self.latest_attestations.hash_tree_root_internal());
+        result.append(&mut self.batched_block_roots.hash_tree_root_internal());
+        result.append(&mut self.latest_eth1_data.hash_tree_root_internal());
+        result.append(&mut self.eth1_data_votes.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -1064,33 +1035,3 @@ impl<T: RngCore> TestRandom<T> for BeaconState {
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
-
-    #[test]
-    pub fn test_ssz_round_trip() {
-        let mut rng = XorShiftRng::from_seed([42; 16]);
-        let original = BeaconState::random_for_test(&mut rng);
-
-        let bytes = ssz_encode(&original);
-        let (decoded, _) = <_>::ssz_decode(&bytes, 0).unwrap();
-
-        assert_eq!(original, decoded);
-    }
-
-    #[test]
-    pub fn test_hash_tree_root() {
-        let mut rng = XorShiftRng::from_seed([42; 16]);
-        let original = BeaconState::random_for_test(&mut rng);
-
-        let result = original.hash_tree_root();
-
-        assert_eq!(result.len(), 32);
-        // TODO: Add further tests
-        // https://github.com/sigp/lighthouse/issues/170
-    }
-}

eth2/types/src/beacon_state/tests.rs

@@ -0,0 +1,97 @@
+#![cfg(test)]
+
+use super::*;
+use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
+use crate::{
+    beacon_state::BeaconStateError, BeaconState, ChainSpec, Deposit, DepositData, DepositInput,
+    Eth1Data, Hash256, Keypair,
+};
+use bls::create_proof_of_possession;
+use ssz::{ssz_encode, Decodable};
+
+struct BeaconStateTestBuilder {
+    pub genesis_time: u64,
+    pub initial_validator_deposits: Vec<Deposit>,
+    pub latest_eth1_data: Eth1Data,
+    pub spec: ChainSpec,
+    pub keypairs: Vec<Keypair>,
+}
+
+impl BeaconStateTestBuilder {
+    pub fn with_random_validators(validator_count: usize) -> Self {
+        let genesis_time = 10_000_000;
+        let keypairs: Vec<Keypair> = (0..validator_count)
+            .collect::<Vec<usize>>()
+            .iter()
+            .map(|_| Keypair::random())
+            .collect();
+        let initial_validator_deposits = keypairs
+            .iter()
+            .map(|keypair| Deposit {
+                branch: vec![], // branch verification is not specified.
+                index: 0,       // index verification is not specified.
+                deposit_data: DepositData {
+                    amount: 32_000_000_000, // 32 ETH (in Gwei)
+                    timestamp: genesis_time - 1,
+                    deposit_input: DepositInput {
+                        pubkey: keypair.pk.clone(),
+                        withdrawal_credentials: Hash256::zero(), // Withdrawal not possible.
+                        proof_of_possession: create_proof_of_possession(&keypair),
+                    },
+                },
+            })
+            .collect();
+        let latest_eth1_data = Eth1Data {
+            deposit_root: Hash256::zero(),
+            block_hash: Hash256::zero(),
+        };
+        let spec = ChainSpec::foundation();
+
+        Self {
+            genesis_time,
+            initial_validator_deposits,
+            latest_eth1_data,
+            spec,
+            keypairs,
+        }
+    }
+
+    pub fn build(&self) -> Result<BeaconState, BeaconStateError> {
+        BeaconState::genesis(
+            self.genesis_time,
+            self.initial_validator_deposits.clone(),
+            self.latest_eth1_data.clone(),
+            &self.spec,
+        )
+    }
+}
+
+#[test]
+pub fn can_produce_genesis_block() {
+    let builder = BeaconStateTestBuilder::with_random_validators(2);
+
+    builder.build().unwrap();
+}
+
+#[test]
+pub fn test_ssz_round_trip() {
+    let mut rng = XorShiftRng::from_seed([42; 16]);
+    let original = BeaconState::random_for_test(&mut rng);
+
+    let bytes = ssz_encode(&original);
+    let (decoded, _) = <_>::ssz_decode(&bytes, 0).unwrap();
+
+    assert_eq!(original, decoded);
+}
+
+#[test]
+pub fn test_hash_tree_root_internal() {
+    let mut rng = XorShiftRng::from_seed([42; 16]);
+    let original = BeaconState::random_for_test(&mut rng);
+
+    let result = original.hash_tree_root_internal();
+
+    assert_eq!(result.len(), 32);
+    // TODO: Add further tests
+    // https://github.com/sigp/lighthouse/issues/170
+}

eth2/types/src/beacon_state_tests.rs

@@ -1,72 +0,0 @@
-#[cfg(test)]
-mod tests {
-    use crate::{
-        beacon_state::BeaconStateError, BeaconState, ChainSpec, Deposit, DepositData, DepositInput,
-        Eth1Data, Hash256, Keypair,
-    };
-    use bls::create_proof_of_possession;
-
-    struct BeaconStateTestBuilder {
-        pub genesis_time: u64,
-        pub initial_validator_deposits: Vec<Deposit>,
-        pub latest_eth1_data: Eth1Data,
-        pub spec: ChainSpec,
-        pub keypairs: Vec<Keypair>,
-    }
-
-    impl BeaconStateTestBuilder {
-        pub fn with_random_validators(validator_count: usize) -> Self {
-            let genesis_time = 10_000_000;
-            let keypairs: Vec<Keypair> = (0..validator_count)
-                .collect::<Vec<usize>>()
-                .iter()
-                .map(|_| Keypair::random())
-                .collect();
-            let initial_validator_deposits = keypairs
-                .iter()
-                .map(|keypair| Deposit {
-                    branch: vec![], // branch verification is not specified.
-                    index: 0,       // index verification is not specified.
-                    deposit_data: DepositData {
-                        amount: 32_000_000_000, // 32 ETH (in Gwei)
-                        timestamp: genesis_time - 1,
-                        deposit_input: DepositInput {
-                            pubkey: keypair.pk.clone(),
-                            withdrawal_credentials: Hash256::zero(), // Withdrawal not possible.
-                            proof_of_possession: create_proof_of_possession(&keypair),
-                        },
-                    },
-                })
-                .collect();
-            let latest_eth1_data = Eth1Data {
-                deposit_root: Hash256::zero(),
-                block_hash: Hash256::zero(),
-            };
-            let spec = ChainSpec::foundation();
-
-            Self {
-                genesis_time,
-                initial_validator_deposits,
-                latest_eth1_data,
-                spec,
-                keypairs,
-            }
-        }
-
-        pub fn build(&self) -> Result<BeaconState, BeaconStateError> {
-            BeaconState::genesis(
-                self.genesis_time,
-                self.initial_validator_deposits.clone(),
-                self.latest_eth1_data.clone(),
-                &self.spec,
-            )
-        }
-    }
-
-    #[test]
-    pub fn can_produce_genesis_block() {
-        let builder = BeaconStateTestBuilder::with_random_validators(2);
-
-        builder.build().unwrap();
-    }
-}

eth2/types/src/casper_slashing.rs

@@ -2,41 +2,20 @@ use super::SlashableVoteData;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct CasperSlashing {
     pub slashable_vote_data_1: SlashableVoteData,
     pub slashable_vote_data_2: SlashableVoteData,
 }
 
-impl Encodable for CasperSlashing {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.slashable_vote_data_1);
-        s.append(&self.slashable_vote_data_2);
-    }
-}
-
-impl Decodable for CasperSlashing {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (slashable_vote_data_1, i) = <_>::ssz_decode(bytes, i)?;
-        let (slashable_vote_data_2, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            CasperSlashing {
-                slashable_vote_data_1,
-                slashable_vote_data_2,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for CasperSlashing {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slashable_vote_data_1.hash_tree_root());
-        result.append(&mut self.slashable_vote_data_2.hash_tree_root());
+        result.append(&mut self.slashable_vote_data_1.hash_tree_root_internal());
+        result.append(&mut self.slashable_vote_data_2.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -54,7 +33,7 @@ impl<T: RngCore> TestRandom<T> for CasperSlashing {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -68,11 +47,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = CasperSlashing::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/chain_spec.rs

@@ -1,7 +1,96 @@
-use crate::{Address, ChainSpec, Epoch, Hash256, Signature, Slot};
+use crate::{Address, Epoch, Hash256, Slot};
+use bls::Signature;
 
 const GWEI: u64 = 1_000_000_000;
 
+/// Holds all the "constants" for a BeaconChain.
+///
+/// Spec v0.2.0
+#[derive(PartialEq, Debug, Clone)]
+pub struct ChainSpec {
+    /*
+     * Misc
+     */
+    pub shard_count: u64,
+    pub target_committee_size: u64,
+    pub max_balance_churn_quotient: u64,
+    pub beacon_chain_shard_number: u64,
+    pub max_indices_per_slashable_vote: u64,
+    pub max_withdrawals_per_epoch: u64,
+    pub shuffle_round_count: u8,
+
+    /*
+     *  Deposit contract
+     */
+    pub deposit_contract_address: Address,
+    pub deposit_contract_tree_depth: u64,
+
+    /*
+     *  Gwei values
+     */
+    pub min_deposit_amount: u64,
+    pub max_deposit_amount: u64,
+    pub fork_choice_balance_increment: u64,
+    pub ejection_balance: u64,
+
+    /*
+     * Initial Values
+     */
+    pub genesis_fork_version: u64,
+    pub genesis_slot: Slot,
+    pub genesis_epoch: Epoch,
+    pub genesis_start_shard: u64,
+    pub far_future_epoch: Epoch,
+    pub zero_hash: Hash256,
+    pub empty_signature: Signature,
+    pub bls_withdrawal_prefix_byte: u8,
+
+    /*
+     * Time parameters
+     */
+    pub slot_duration: u64,
+    pub min_attestation_inclusion_delay: u64,
+    pub epoch_length: u64,
+    pub seed_lookahead: Epoch,
+    pub entry_exit_delay: u64,
+    pub eth1_data_voting_period: u64,
+    pub min_validator_withdrawal_epochs: Epoch,
+
+    /*
+     * State list lengths
+     */
+    pub latest_block_roots_length: usize,
+    pub latest_randao_mixes_length: usize,
+    pub latest_index_roots_length: usize,
+    pub latest_penalized_exit_length: usize,
+
+    /*
+     * Reward and penalty quotients
+     */
+    pub base_reward_quotient: u64,
+    pub whistleblower_reward_quotient: u64,
+    pub includer_reward_quotient: u64,
+    pub inactivity_penalty_quotient: u64,
+
+    /*
+     * Max operations per block
+     */
+    pub max_proposer_slashings: u64,
+    pub max_attester_slashings: u64,
+    pub max_attestations: u64,
+    pub max_deposits: u64,
+    pub max_exits: u64,
+
+    /*
+     * Signature domains
+     */
+    pub domain_deposit: u64,
+    pub domain_attestation: u64,
+    pub domain_proposal: u64,
+    pub domain_exit: u64,
+    pub domain_randao: u64,
+}
+
 impl ChainSpec {
     /// Returns a `ChainSpec` compatible with the specification from Ethereum Foundation.
     ///
@@ -100,6 +189,26 @@ impl ChainSpec {
     }
 }
 
+impl ChainSpec {
+    /// Returns a `ChainSpec` compatible with the specification suitable for 8 validators.
+    ///
+    /// Spec v0.2.0
+    pub fn few_validators() -> Self {
+        let genesis_slot = Slot::new(2_u64.pow(19));
+        let epoch_length = 8;
+        let genesis_epoch = genesis_slot.epoch(epoch_length);
+
+        Self {
+            shard_count: 1,
+            target_committee_size: 1,
+            genesis_slot,
+            genesis_epoch,
+            epoch_length,
+            ..ChainSpec::foundation()
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

eth2/types/src/crosslink.rs

@@ -2,9 +2,10 @@ use crate::test_utils::TestRandom;
 use crate::{Epoch, Hash256};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize, Hash)]
+#[derive(Debug, Clone, PartialEq, Default, Serialize, Hash, Encode, Decode)]
 pub struct Crosslink {
     pub epoch: Epoch,
     pub shard_block_root: Hash256,
@@ -20,33 +21,11 @@ impl Crosslink {
     }
 }
 
-impl Encodable for Crosslink {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.epoch);
-        s.append(&self.shard_block_root);
-    }
-}
-
-impl Decodable for Crosslink {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (shard_block_root, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                epoch,
-                shard_block_root,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for Crosslink {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.epoch.hash_tree_root());
-        result.append(&mut self.shard_block_root.hash_tree_root());
+        result.append(&mut self.epoch.hash_tree_root_internal());
+        result.append(&mut self.shard_block_root.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -64,7 +43,7 @@ impl<T: RngCore> TestRandom<T> for Crosslink {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -78,11 +57,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Crosslink::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/deposit.rs

@@ -2,46 +2,22 @@ use super::{DepositData, Hash256};
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct Deposit {
     pub branch: Vec<Hash256>,
     pub index: u64,
     pub deposit_data: DepositData,
 }
 
-impl Encodable for Deposit {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append_vec(&self.branch);
-        s.append(&self.index);
-        s.append(&self.deposit_data);
-    }
-}
-
-impl Decodable for Deposit {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (branch, i) = <_>::ssz_decode(bytes, i)?;
-        let (index, i) = <_>::ssz_decode(bytes, i)?;
-        let (deposit_data, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                branch,
-                index,
-                deposit_data,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for Deposit {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.branch.hash_tree_root());
-        result.append(&mut self.index.hash_tree_root());
-        result.append(&mut self.deposit_data.hash_tree_root());
+        result.append(&mut self.branch.hash_tree_root_internal());
+        result.append(&mut self.index.hash_tree_root_internal());
+        result.append(&mut self.deposit_data.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -60,7 +36,7 @@ impl<T: RngCore> TestRandom<T> for Deposit {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -74,11 +50,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Deposit::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/deposit_data.rs

@@ -2,46 +2,22 @@ use super::DepositInput;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct DepositData {
     pub amount: u64,
     pub timestamp: u64,
     pub deposit_input: DepositInput,
 }
 
-impl Encodable for DepositData {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.amount);
-        s.append(&self.timestamp);
-        s.append(&self.deposit_input);
-    }
-}
-
-impl Decodable for DepositData {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (amount, i) = <_>::ssz_decode(bytes, i)?;
-        let (timestamp, i) = <_>::ssz_decode(bytes, i)?;
-        let (deposit_input, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                amount,
-                timestamp,
-                deposit_input,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for DepositData {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.amount.hash_tree_root());
-        result.append(&mut self.timestamp.hash_tree_root());
-        result.append(&mut self.deposit_input.hash_tree_root());
+        result.append(&mut self.amount.hash_tree_root_internal());
+        result.append(&mut self.timestamp.hash_tree_root_internal());
+        result.append(&mut self.deposit_input.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -60,7 +36,7 @@ impl<T: RngCore> TestRandom<T> for DepositData {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -74,11 +50,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = DepositData::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/deposit_input.rs

@@ -3,46 +3,22 @@ use crate::test_utils::TestRandom;
 use bls::{PublicKey, Signature};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct DepositInput {
     pub pubkey: PublicKey,
     pub withdrawal_credentials: Hash256,
     pub proof_of_possession: Signature,
 }
 
-impl Encodable for DepositInput {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.pubkey);
-        s.append(&self.withdrawal_credentials);
-        s.append(&self.proof_of_possession);
-    }
-}
-
-impl Decodable for DepositInput {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (pubkey, i) = <_>::ssz_decode(bytes, i)?;
-        let (withdrawal_credentials, i) = <_>::ssz_decode(bytes, i)?;
-        let (proof_of_possession, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                pubkey,
-                withdrawal_credentials,
-                proof_of_possession,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for DepositInput {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.pubkey.hash_tree_root());
-        result.append(&mut self.withdrawal_credentials.hash_tree_root());
-        result.append(&mut self.proof_of_possession.hash_tree_root());
+        result.append(&mut self.pubkey.hash_tree_root_internal());
+        result.append(&mut self.withdrawal_credentials.hash_tree_root_internal());
+        result.append(&mut self.proof_of_possession.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -61,7 +37,7 @@ impl<T: RngCore> TestRandom<T> for DepositInput {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -75,11 +51,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = DepositInput::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/eth1_data.rs

@@ -2,42 +2,21 @@ use super::Hash256;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
 // Note: this is refer to as DepositRootVote in specs
-#[derive(Debug, PartialEq, Clone, Default, Serialize)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode)]
 pub struct Eth1Data {
     pub deposit_root: Hash256,
     pub block_hash: Hash256,
 }
 
-impl Encodable for Eth1Data {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.deposit_root);
-        s.append(&self.block_hash);
-    }
-}
-
-impl Decodable for Eth1Data {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (deposit_root, i) = <_>::ssz_decode(bytes, i)?;
-        let (block_hash, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                deposit_root,
-                block_hash,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for Eth1Data {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.deposit_root.hash_tree_root());
-        result.append(&mut self.block_hash.hash_tree_root());
+        result.append(&mut self.deposit_root.hash_tree_root_internal());
+        result.append(&mut self.block_hash.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -55,7 +34,7 @@ impl<T: RngCore> TestRandom<T> for Eth1Data {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -69,11 +48,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Eth1Data::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/eth1_data_vote.rs

@@ -2,42 +2,21 @@ use super::Eth1Data;
 use crate::test_utils::TestRandom;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
 // Note: this is refer to as DepositRootVote in specs
-#[derive(Debug, PartialEq, Clone, Default, Serialize)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode)]
 pub struct Eth1DataVote {
     pub eth1_data: Eth1Data,
     pub vote_count: u64,
 }
 
-impl Encodable for Eth1DataVote {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.eth1_data);
-        s.append(&self.vote_count);
-    }
-}
-
-impl Decodable for Eth1DataVote {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (eth1_data, i) = <_>::ssz_decode(bytes, i)?;
-        let (vote_count, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                eth1_data,
-                vote_count,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for Eth1DataVote {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.eth1_data.hash_tree_root());
-        result.append(&mut self.vote_count.hash_tree_root());
+        result.append(&mut self.eth1_data.hash_tree_root_internal());
+        result.append(&mut self.vote_count.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -55,7 +34,7 @@ impl<T: RngCore> TestRandom<T> for Eth1DataVote {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -69,11 +48,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Eth1DataVote::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/exit.rs

@@ -2,46 +2,22 @@ use crate::{test_utils::TestRandom, Epoch};
 use bls::Signature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct Exit {
     pub epoch: Epoch,
     pub validator_index: u64,
     pub signature: Signature,
 }
 
-impl Encodable for Exit {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.epoch);
-        s.append(&self.validator_index);
-        s.append(&self.signature);
-    }
-}
-
-impl Decodable for Exit {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (epoch, i) = <_>::ssz_decode(bytes, i)?;
-        let (validator_index, i) = <_>::ssz_decode(bytes, i)?;
-        let (signature, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                epoch,
-                validator_index,
-                signature,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for Exit {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.epoch.hash_tree_root());
-        result.append(&mut self.validator_index.hash_tree_root());
-        result.append(&mut self.signature.hash_tree_root());
+        result.append(&mut self.epoch.hash_tree_root_internal());
+        result.append(&mut self.validator_index.hash_tree_root_internal());
+        result.append(&mut self.signature.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -60,7 +36,7 @@ impl<T: RngCore> TestRandom<T> for Exit {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -74,11 +50,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Exit::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/fork.rs

@@ -1,46 +1,22 @@
 use crate::{test_utils::TestRandom, Epoch};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, Clone, PartialEq, Default, Serialize)]
+#[derive(Debug, Clone, PartialEq, Default, Serialize, Encode, Decode)]
 pub struct Fork {
     pub previous_version: u64,
     pub current_version: u64,
     pub epoch: Epoch,
 }
 
-impl Encodable for Fork {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.previous_version);
-        s.append(&self.current_version);
-        s.append(&self.epoch);
-    }
-}
-
-impl Decodable for Fork {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (previous_version, i) = <_>::ssz_decode(bytes, i)?;
-        let (current_version, i) = <_>::ssz_decode(bytes, i)?;
-        let (epoch, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                previous_version,
-                current_version,
-                epoch,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for Fork {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.previous_version.hash_tree_root());
-        result.append(&mut self.current_version.hash_tree_root());
-        result.append(&mut self.epoch.hash_tree_root());
+        result.append(&mut self.previous_version.hash_tree_root_internal());
+        result.append(&mut self.current_version.hash_tree_root_internal());
+        result.append(&mut self.epoch.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -59,7 +35,7 @@ impl<T: RngCore> TestRandom<T> for Fork {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -73,11 +49,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Fork::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/lib.rs

@@ -7,8 +7,8 @@ pub mod attester_slashing;
 pub mod beacon_block;
 pub mod beacon_block_body;
 pub mod beacon_state;
-pub mod beacon_state_tests;
 pub mod casper_slashing;
+pub mod chain_spec;
 pub mod crosslink;
 pub mod deposit;
 pub mod deposit_data;
@@ -29,7 +29,6 @@ pub mod slashable_vote_data;
 pub mod slot_epoch_macros;
 pub mod slot_epoch;
 pub mod slot_height;
-pub mod spec;
 pub mod validator;
 pub mod validator_registry;
 pub mod validator_registry_delta_block;
@@ -45,6 +44,7 @@ pub use crate::beacon_block::BeaconBlock;
 pub use crate::beacon_block_body::BeaconBlockBody;
 pub use crate::beacon_state::BeaconState;
 pub use crate::casper_slashing::CasperSlashing;
+pub use crate::chain_spec::ChainSpec;
 pub use crate::crosslink::Crosslink;
 pub use crate::deposit::Deposit;
 pub use crate::deposit_data::DepositData;
@@ -61,7 +61,6 @@ pub use crate::slashable_attestation::SlashableAttestation;
 pub use crate::slashable_vote_data::SlashableVoteData;
 pub use crate::slot_epoch::{Epoch, Slot};
 pub use crate::slot_height::SlotHeight;
-pub use crate::spec::ChainSpec;
 pub use crate::validator::{StatusFlags as ValidatorStatusFlags, Validator};
 pub use crate::validator_registry_delta_block::ValidatorRegistryDeltaBlock;
 

eth2/types/src/pending_attestation.rs

@@ -2,9 +2,10 @@ use crate::test_utils::TestRandom;
 use crate::{AttestationData, Bitfield, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, Clone, PartialEq, Serialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode)]
 pub struct PendingAttestation {
     pub aggregation_bitfield: Bitfield,
     pub data: AttestationData,
@@ -12,41 +13,13 @@ pub struct PendingAttestation {
     pub inclusion_slot: Slot,
 }
 
-impl Encodable for PendingAttestation {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.aggregation_bitfield);
-        s.append(&self.data);
-        s.append(&self.custody_bitfield);
-        s.append(&self.inclusion_slot);
-    }
-}
-
-impl Decodable for PendingAttestation {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (aggregation_bitfield, i) = <_>::ssz_decode(bytes, i)?;
-        let (data, i) = <_>::ssz_decode(bytes, i)?;
-        let (custody_bitfield, i) = <_>::ssz_decode(bytes, i)?;
-        let (inclusion_slot, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                data,
-                aggregation_bitfield,
-                custody_bitfield,
-                inclusion_slot,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for PendingAttestation {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.aggregation_bitfield.hash_tree_root());
-        result.append(&mut self.data.hash_tree_root());
-        result.append(&mut self.custody_bitfield.hash_tree_root());
-        result.append(&mut self.inclusion_slot.hash_tree_root());
+        result.append(&mut self.aggregation_bitfield.hash_tree_root_internal());
+        result.append(&mut self.data.hash_tree_root_internal());
+        result.append(&mut self.custody_bitfield.hash_tree_root_internal());
+        result.append(&mut self.inclusion_slot.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -66,7 +39,7 @@ impl<T: RngCore> TestRandom<T> for PendingAttestation {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -80,11 +53,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = PendingAttestation::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/proposal_signed_data.rs

@@ -2,46 +2,22 @@ use crate::test_utils::TestRandom;
 use crate::{Hash256, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Default, Serialize)]
+#[derive(Debug, PartialEq, Clone, Default, Serialize, Encode, Decode)]
 pub struct ProposalSignedData {
     pub slot: Slot,
     pub shard: u64,
     pub block_root: Hash256,
 }
 
-impl Encodable for ProposalSignedData {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.slot);
-        s.append(&self.shard);
-        s.append(&self.block_root);
-    }
-}
-
-impl Decodable for ProposalSignedData {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (slot, i) = <_>::ssz_decode(bytes, i)?;
-        let (shard, i) = <_>::ssz_decode(bytes, i)?;
-        let (block_root, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            ProposalSignedData {
-                slot,
-                shard,
-                block_root,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for ProposalSignedData {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.slot.hash_tree_root());
-        result.append(&mut self.shard.hash_tree_root());
-        result.append(&mut self.block_root.hash_tree_root());
+        result.append(&mut self.slot.hash_tree_root_internal());
+        result.append(&mut self.shard.hash_tree_root_internal());
+        result.append(&mut self.block_root.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -60,7 +36,7 @@ impl<T: RngCore> TestRandom<T> for ProposalSignedData {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -74,11 +50,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = ProposalSignedData::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/proposer_slashing.rs

@@ -3,9 +3,10 @@ use crate::test_utils::TestRandom;
 use bls::Signature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct ProposerSlashing {
     pub proposer_index: u64,
     pub proposal_data_1: ProposalSignedData,
@@ -14,45 +15,14 @@ pub struct ProposerSlashing {
     pub proposal_signature_2: Signature,
 }
 
-impl Encodable for ProposerSlashing {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.proposer_index);
-        s.append(&self.proposal_data_1);
-        s.append(&self.proposal_signature_1);
-        s.append(&self.proposal_data_2);
-        s.append(&self.proposal_signature_2);
-    }
-}
-
-impl Decodable for ProposerSlashing {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (proposer_index, i) = <_>::ssz_decode(bytes, i)?;
-        let (proposal_data_1, i) = <_>::ssz_decode(bytes, i)?;
-        let (proposal_signature_1, i) = <_>::ssz_decode(bytes, i)?;
-        let (proposal_data_2, i) = <_>::ssz_decode(bytes, i)?;
-        let (proposal_signature_2, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            ProposerSlashing {
-                proposer_index,
-                proposal_data_1,
-                proposal_signature_1,
-                proposal_data_2,
-                proposal_signature_2,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for ProposerSlashing {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.proposer_index.hash_tree_root());
-        result.append(&mut self.proposal_data_1.hash_tree_root());
-        result.append(&mut self.proposal_signature_1.hash_tree_root());
-        result.append(&mut self.proposal_data_2.hash_tree_root());
-        result.append(&mut self.proposal_signature_2.hash_tree_root());
+        result.append(&mut self.proposer_index.hash_tree_root_internal());
+        result.append(&mut self.proposal_data_1.hash_tree_root_internal());
+        result.append(&mut self.proposal_signature_1.hash_tree_root_internal());
+        result.append(&mut self.proposal_data_2.hash_tree_root_internal());
+        result.append(&mut self.proposal_signature_2.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -73,7 +43,7 @@ impl<T: RngCore> TestRandom<T> for ProposerSlashing {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -87,11 +57,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = ProposerSlashing::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/shard_reassignment_record.rs

@@ -1,46 +1,22 @@
 use crate::{test_utils::TestRandom, Slot};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct ShardReassignmentRecord {
     pub validator_index: u64,
     pub shard: u64,
     pub slot: Slot,
 }
 
-impl Encodable for ShardReassignmentRecord {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.validator_index);
-        s.append(&self.shard);
-        s.append(&self.slot);
-    }
-}
-
-impl Decodable for ShardReassignmentRecord {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (validator_index, i) = <_>::ssz_decode(bytes, i)?;
-        let (shard, i) = <_>::ssz_decode(bytes, i)?;
-        let (slot, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                validator_index,
-                shard,
-                slot,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for ShardReassignmentRecord {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.validator_index.hash_tree_root());
-        result.append(&mut self.shard.hash_tree_root());
-        result.append(&mut self.slot.hash_tree_root());
+        result.append(&mut self.validator_index.hash_tree_root_internal());
+        result.append(&mut self.shard.hash_tree_root_internal());
+        result.append(&mut self.slot.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -59,7 +35,7 @@ impl<T: RngCore> TestRandom<T> for ShardReassignmentRecord {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -73,11 +49,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = ShardReassignmentRecord::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/slashable_attestation.rs

@@ -1,9 +1,10 @@
 use crate::{test_utils::TestRandom, AggregateSignature, AttestationData, Bitfield};
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct SlashableAttestation {
     pub validator_indices: Vec<u64>,
     pub data: AttestationData,
@@ -11,41 +12,13 @@ pub struct SlashableAttestation {
     pub aggregate_signature: AggregateSignature,
 }
 
-impl Encodable for SlashableAttestation {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append_vec(&self.validator_indices);
-        s.append(&self.data);
-        s.append(&self.custody_bitfield);
-        s.append(&self.aggregate_signature);
-    }
-}
-
-impl Decodable for SlashableAttestation {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (validator_indices, i) = <_>::ssz_decode(bytes, i)?;
-        let (data, i) = <_>::ssz_decode(bytes, i)?;
-        let (custody_bitfield, i) = <_>::ssz_decode(bytes, i)?;
-        let (aggregate_signature, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            SlashableAttestation {
-                validator_indices,
-                data,
-                custody_bitfield,
-                aggregate_signature,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for SlashableAttestation {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.validator_indices.hash_tree_root());
-        result.append(&mut self.data.hash_tree_root());
-        result.append(&mut self.custody_bitfield.hash_tree_root());
-        result.append(&mut self.aggregate_signature.hash_tree_root());
+        result.append(&mut self.validator_indices.hash_tree_root_internal());
+        result.append(&mut self.data.hash_tree_root_internal());
+        result.append(&mut self.custody_bitfield.hash_tree_root_internal());
+        result.append(&mut self.aggregate_signature.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -65,7 +38,7 @@ impl<T: RngCore> TestRandom<T> for SlashableAttestation {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -79,11 +52,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = SlashableAttestation::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/slashable_vote_data.rs

@@ -1,11 +1,13 @@
 use super::AttestationData;
+use crate::chain_spec::ChainSpec;
 use crate::test_utils::TestRandom;
 use bls::AggregateSignature;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
-#[derive(Debug, PartialEq, Clone, Serialize)]
+#[derive(Debug, PartialEq, Clone, Serialize, Encode, Decode)]
 pub struct SlashableVoteData {
     pub custody_bit_0_indices: Vec<u32>,
     pub custody_bit_1_indices: Vec<u32>,
@@ -13,41 +15,34 @@ pub struct SlashableVoteData {
     pub aggregate_signature: AggregateSignature,
 }
 
-impl Encodable for SlashableVoteData {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append_vec(&self.custody_bit_0_indices);
-        s.append_vec(&self.custody_bit_1_indices);
-        s.append(&self.data);
-        s.append(&self.aggregate_signature);
-    }
+impl SlashableVoteData {
+    /// Check if ``attestation_data_1`` and ``attestation_data_2`` have the same target.
+    ///
+    /// Spec v0.3.0
+    pub fn is_double_vote(&self, other: &SlashableVoteData, spec: &ChainSpec) -> bool {
+        self.data.slot.epoch(spec.epoch_length) == other.data.slot.epoch(spec.epoch_length)
     }
 
-impl Decodable for SlashableVoteData {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (custody_bit_0_indices, i) = <_>::ssz_decode(bytes, i)?;
-        let (custody_bit_1_indices, i) = <_>::ssz_decode(bytes, i)?;
-        let (data, i) = <_>::ssz_decode(bytes, i)?;
-        let (aggregate_signature, i) = <_>::ssz_decode(bytes, i)?;
+    /// Check if ``attestation_data_1`` surrounds ``attestation_data_2``.
+    ///
+    /// Spec v0.3.0
+    pub fn is_surround_vote(&self, other: &SlashableVoteData, spec: &ChainSpec) -> bool {
+        let source_epoch_1 = self.data.justified_epoch;
+        let source_epoch_2 = other.data.justified_epoch;
+        let target_epoch_1 = self.data.slot.epoch(spec.epoch_length);
+        let target_epoch_2 = other.data.slot.epoch(spec.epoch_length);
 
-        Ok((
-            SlashableVoteData {
-                custody_bit_0_indices,
-                custody_bit_1_indices,
-                data,
-                aggregate_signature,
-            },
-            i,
-        ))
+        (source_epoch_1 < source_epoch_2) && (target_epoch_2 < target_epoch_1)
     }
 }
 
 impl TreeHash for SlashableVoteData {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.custody_bit_0_indices.hash_tree_root());
-        result.append(&mut self.custody_bit_1_indices.hash_tree_root());
-        result.append(&mut self.data.hash_tree_root());
-        result.append(&mut self.aggregate_signature.hash_tree_root());
+        result.append(&mut self.custody_bit_0_indices.hash_tree_root_internal());
+        result.append(&mut self.custody_bit_1_indices.hash_tree_root_internal());
+        result.append(&mut self.data.hash_tree_root_internal());
+        result.append(&mut self.aggregate_signature.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -66,8 +61,82 @@ impl<T: RngCore> TestRandom<T> for SlashableVoteData {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::chain_spec::ChainSpec;
+    use crate::slot_epoch::{Epoch, Slot};
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
+
+    #[test]
+    pub fn test_is_double_vote_true() {
+        let spec = ChainSpec::foundation();
+        let slashable_vote_first = create_slashable_vote_data(1, 1, &spec);
+        let slashable_vote_second = create_slashable_vote_data(1, 1, &spec);
+
+        assert_eq!(
+            slashable_vote_first.is_double_vote(&slashable_vote_second, &spec),
+            true
+        )
+    }
+
+    #[test]
+    pub fn test_is_double_vote_false() {
+        let spec = ChainSpec::foundation();
+        let slashable_vote_first = create_slashable_vote_data(1, 1, &spec);
+        let slashable_vote_second = create_slashable_vote_data(2, 1, &spec);
+
+        assert_eq!(
+            slashable_vote_first.is_double_vote(&slashable_vote_second, &spec),
+            false
+        );
+    }
+
+    #[test]
+    pub fn test_is_surround_vote_true() {
+        let spec = ChainSpec::foundation();
+        let slashable_vote_first = create_slashable_vote_data(2, 1, &spec);
+        let slashable_vote_second = create_slashable_vote_data(1, 2, &spec);
+
+        assert_eq!(
+            slashable_vote_first.is_surround_vote(&slashable_vote_second, &spec),
+            true
+        );
+    }
+
+    #[test]
+    pub fn test_is_surround_vote_true_realistic() {
+        let spec = ChainSpec::foundation();
+        let slashable_vote_first = create_slashable_vote_data(4, 1, &spec);
+        let slashable_vote_second = create_slashable_vote_data(3, 2, &spec);
+
+        assert_eq!(
+            slashable_vote_first.is_surround_vote(&slashable_vote_second, &spec),
+            true
+        );
+    }
+
+    #[test]
+    pub fn test_is_surround_vote_false_source_epoch_fails() {
+        let spec = ChainSpec::foundation();
+        let slashable_vote_first = create_slashable_vote_data(2, 2, &spec);
+        let slashable_vote_second = create_slashable_vote_data(1, 1, &spec);
+
+        assert_eq!(
+            slashable_vote_first.is_surround_vote(&slashable_vote_second, &spec),
+            false
+        );
+    }
+
+    #[test]
+    pub fn test_is_surround_vote_false_target_epoch_fails() {
+        let spec = ChainSpec::foundation();
+        let slashable_vote_first = create_slashable_vote_data(1, 1, &spec);
+        let slashable_vote_second = create_slashable_vote_data(2, 2, &spec);
+
+        assert_eq!(
+            slashable_vote_first.is_surround_vote(&slashable_vote_second, &spec),
+            false
+        );
+    }
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -81,14 +150,27 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = SlashableVoteData::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests
         // https://github.com/sigp/lighthouse/issues/170
     }
+
+    fn create_slashable_vote_data(
+        slot_factor: u64,
+        justified_epoch: u64,
+        spec: &ChainSpec,
+    ) -> SlashableVoteData {
+        let mut rng = XorShiftRng::from_seed([42; 16]);
+        let mut slashable_vote = SlashableVoteData::random_for_test(&mut rng);
+
+        slashable_vote.data.slot = Slot::new(slot_factor * spec.epoch_length);
+        slashable_vote.data.justified_epoch = Epoch::new(justified_epoch);
+        slashable_vote
+    }
 }

eth2/types/src/slot_epoch_macros.rs

@@ -25,12 +25,14 @@ macro_rules! impl_into_u32 {
     ($main: ident) => {
         impl Into<u32> for $main {
             fn into(self) -> u32 {
+                assert!(self.0 < u64::from(std::u32::MAX), "Lossy conversion to u32");
                 self.0 as u32
             }
         }
 
         impl $main {
             pub fn as_u32(&self) -> u32 {
+                assert!(self.0 < u64::from(std::u32::MAX), "Lossy conversion to u32");
                 self.0 as u32
             }
         }
@@ -224,9 +226,9 @@ macro_rules! impl_ssz {
         }
 
         impl TreeHash for $type {
-            fn hash_tree_root(&self) -> Vec<u8> {
+            fn hash_tree_root_internal(&self) -> Vec<u8> {
                 let mut result: Vec<u8> = vec![];
-                result.append(&mut self.0.hash_tree_root());
+                result.append(&mut self.0.hash_tree_root_internal());
                 hash(&result)
             }
         }
@@ -560,11 +562,11 @@ macro_rules! ssz_tests {
         }
 
         #[test]
-        pub fn test_hash_tree_root() {
+        pub fn test_hash_tree_root_internal() {
             let mut rng = XorShiftRng::from_seed([42; 16]);
             let original = $type::random_for_test(&mut rng);
 
-            let result = original.hash_tree_root();
+            let result = original.hash_tree_root_internal();
 
             assert_eq!(result.len(), 32);
             // TODO: Add further tests

eth2/types/src/spec/mod.rs

@@ -1,92 +0,0 @@
-mod foundation;
-
-use crate::{Address, Epoch, Hash256, Slot};
-use bls::Signature;
-
-/// Holds all the "constants" for a BeaconChain.
-///
-/// Spec v0.2.0
-#[derive(PartialEq, Debug, Clone)]
-pub struct ChainSpec {
-    /*
-     * Misc
-     */
-    pub shard_count: u64,
-    pub target_committee_size: u64,
-    pub max_balance_churn_quotient: u64,
-    pub beacon_chain_shard_number: u64,
-    pub max_indices_per_slashable_vote: u64,
-    pub max_withdrawals_per_epoch: u64,
-    pub shuffle_round_count: u64,
-
-    /*
-     *  Deposit contract
-     */
-    pub deposit_contract_address: Address,
-    pub deposit_contract_tree_depth: u64,
-
-    /*
-     *  Gwei values
-     */
-    pub min_deposit_amount: u64,
-    pub max_deposit_amount: u64,
-    pub fork_choice_balance_increment: u64,
-    pub ejection_balance: u64,
-
-    /*
-     * Initial Values
-     */
-    pub genesis_fork_version: u64,
-    pub genesis_slot: Slot,
-    pub genesis_epoch: Epoch,
-    pub genesis_start_shard: u64,
-    pub far_future_epoch: Epoch,
-    pub zero_hash: Hash256,
-    pub empty_signature: Signature,
-    pub bls_withdrawal_prefix_byte: u8,
-
-    /*
-     * Time parameters
-     */
-    pub slot_duration: u64,
-    pub min_attestation_inclusion_delay: u64,
-    pub epoch_length: u64,
-    pub seed_lookahead: Epoch,
-    pub entry_exit_delay: u64,
-    pub eth1_data_voting_period: u64,
-    pub min_validator_withdrawal_epochs: Epoch,
-
-    /*
-     * State list lengths
-     */
-    pub latest_block_roots_length: usize,
-    pub latest_randao_mixes_length: usize,
-    pub latest_index_roots_length: usize,
-    pub latest_penalized_exit_length: usize,
-
-    /*
-     * Reward and penalty quotients
-     */
-    pub base_reward_quotient: u64,
-    pub whistleblower_reward_quotient: u64,
-    pub includer_reward_quotient: u64,
-    pub inactivity_penalty_quotient: u64,
-
-    /*
-     * Max operations per block
-     */
-    pub max_proposer_slashings: u64,
-    pub max_attester_slashings: u64,
-    pub max_attestations: u64,
-    pub max_deposits: u64,
-    pub max_exits: u64,
-
-    /*
-     * Signature domains
-     */
-    pub domain_deposit: u64,
-    pub domain_attestation: u64,
-    pub domain_proposal: u64,
-    pub domain_exit: u64,
-    pub domain_randao: u64,
-}

eth2/types/src/validator.rs

@@ -122,15 +122,17 @@ impl Decodable for Validator {
 }
 
 impl TreeHash for Validator {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.pubkey.hash_tree_root());
-        result.append(&mut self.withdrawal_credentials.hash_tree_root());
-        result.append(&mut self.activation_epoch.hash_tree_root());
-        result.append(&mut self.exit_epoch.hash_tree_root());
-        result.append(&mut self.withdrawal_epoch.hash_tree_root());
-        result.append(&mut self.penalized_epoch.hash_tree_root());
-        result.append(&mut u64::from(status_flag_to_byte(self.status_flags)).hash_tree_root());
+        result.append(&mut self.pubkey.hash_tree_root_internal());
+        result.append(&mut self.withdrawal_credentials.hash_tree_root_internal());
+        result.append(&mut self.activation_epoch.hash_tree_root_internal());
+        result.append(&mut self.exit_epoch.hash_tree_root_internal());
+        result.append(&mut self.withdrawal_epoch.hash_tree_root_internal());
+        result.append(&mut self.penalized_epoch.hash_tree_root_internal());
+        result.append(
+            &mut u64::from(status_flag_to_byte(self.status_flags)).hash_tree_root_internal(),
+        );
         hash(&result)
     }
 }
@@ -190,11 +192,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = Validator::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/types/src/validator_registry_delta_block.rs

@@ -2,10 +2,11 @@ use crate::{test_utils::TestRandom, Hash256, Slot};
 use bls::PublicKey;
 use rand::RngCore;
 use serde_derive::Serialize;
-use ssz::{hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
+use ssz::{hash, TreeHash};
+use ssz_derive::{Decode, Encode};
 
 // The information gathered from the PoW chain validator registration function.
-#[derive(Debug, Clone, PartialEq, Serialize)]
+#[derive(Debug, Clone, PartialEq, Serialize, Encode, Decode)]
 pub struct ValidatorRegistryDeltaBlock {
     pub latest_registry_delta_root: Hash256,
     pub validator_index: u32,
@@ -27,45 +28,14 @@ impl Default for ValidatorRegistryDeltaBlock {
     }
 }
 
-impl Encodable for ValidatorRegistryDeltaBlock {
-    fn ssz_append(&self, s: &mut SszStream) {
-        s.append(&self.latest_registry_delta_root);
-        s.append(&self.validator_index);
-        s.append(&self.pubkey);
-        s.append(&self.slot);
-        s.append(&self.flag);
-    }
-}
-
-impl Decodable for ValidatorRegistryDeltaBlock {
-    fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
-        let (latest_registry_delta_root, i) = <_>::ssz_decode(bytes, i)?;
-        let (validator_index, i) = <_>::ssz_decode(bytes, i)?;
-        let (pubkey, i) = <_>::ssz_decode(bytes, i)?;
-        let (slot, i) = <_>::ssz_decode(bytes, i)?;
-        let (flag, i) = <_>::ssz_decode(bytes, i)?;
-
-        Ok((
-            Self {
-                latest_registry_delta_root,
-                validator_index,
-                pubkey,
-                slot,
-                flag,
-            },
-            i,
-        ))
-    }
-}
-
 impl TreeHash for ValidatorRegistryDeltaBlock {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         let mut result: Vec<u8> = vec![];
-        result.append(&mut self.latest_registry_delta_root.hash_tree_root());
-        result.append(&mut self.validator_index.hash_tree_root());
-        result.append(&mut self.pubkey.hash_tree_root());
-        result.append(&mut self.slot.hash_tree_root());
-        result.append(&mut self.flag.hash_tree_root());
+        result.append(&mut self.latest_registry_delta_root.hash_tree_root_internal());
+        result.append(&mut self.validator_index.hash_tree_root_internal());
+        result.append(&mut self.pubkey.hash_tree_root_internal());
+        result.append(&mut self.slot.hash_tree_root_internal());
+        result.append(&mut self.flag.hash_tree_root_internal());
         hash(&result)
     }
 }
@@ -86,7 +56,7 @@ impl<T: RngCore> TestRandom<T> for ValidatorRegistryDeltaBlock {
 mod tests {
     use super::*;
     use crate::test_utils::{SeedableRng, TestRandom, XorShiftRng};
-    use ssz::ssz_encode;
+    use ssz::{ssz_encode, Decodable};
 
     #[test]
     pub fn test_ssz_round_trip() {
@@ -100,11 +70,11 @@ mod tests {
     }
 
     #[test]
-    pub fn test_hash_tree_root() {
+    pub fn test_hash_tree_root_internal() {
         let mut rng = XorShiftRng::from_seed([42; 16]);
         let original = ValidatorRegistryDeltaBlock::random_for_test(&mut rng);
 
-        let result = original.hash_tree_root();
+        let result = original.hash_tree_root_internal();
 
         assert_eq!(result.len(), 32);
         // TODO: Add further tests

eth2/utils/bls/src/aggregate_signature.rs

@@ -57,7 +57,7 @@ impl Serialize for AggregateSignature {
 }
 
 impl TreeHash for AggregateSignature {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         hash(&self.0.as_bytes())
     }
 }

eth2/utils/bls/src/public_key.rs

@@ -66,7 +66,7 @@ impl Serialize for PublicKey {
 }
 
 impl TreeHash for PublicKey {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         hash(&self.0.as_bytes())
     }
 }

eth2/utils/bls/src/secret_key.rs

@@ -41,7 +41,7 @@ impl Decodable for SecretKey {
 }
 
 impl TreeHash for SecretKey {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         self.0.as_bytes().clone()
     }
 }

eth2/utils/bls/src/signature.rs

@@ -61,7 +61,7 @@ impl Decodable for Signature {
 }
 
 impl TreeHash for Signature {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         hash(&self.0.as_bytes())
     }
 }

eth2/utils/boolean-bitfield/src/lib.rs

@@ -187,8 +187,8 @@ impl Serialize for BooleanBitfield {
 }
 
 impl ssz::TreeHash for BooleanBitfield {
-    fn hash_tree_root(&self) -> Vec<u8> {
-        self.to_bytes().hash_tree_root()
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
+        self.to_bytes().hash_tree_root_internal()
     }
 }
 

eth2/utils/ssz/src/impl_decode.rs

@@ -39,6 +39,21 @@ impl Decodable for u8 {
     }
 }
 
+impl Decodable for bool {
+    fn ssz_decode(bytes: &[u8], index: usize) -> Result<(Self, usize), DecodeError> {
+        if index >= bytes.len() {
+            Err(DecodeError::TooShort)
+        } else {
+            let result = match bytes[index] {
+                0b0000_0000 => false,
+                0b1000_0000 => true,
+                _ => return Err(DecodeError::Invalid),
+            };
+            Ok((result, index + 1))
+        }
+    }
+}
+
 impl Decodable for H256 {
     fn ssz_decode(bytes: &[u8], index: usize) -> Result<(Self, usize), DecodeError> {
         if bytes.len() < 32 || bytes.len() - 32 < index {
@@ -215,4 +230,20 @@ mod tests {
         let result: u16 = decode_ssz(&vec![0, 0, 0, 0, 1], 3).unwrap().0;
         assert_eq!(result, 1);
     }
+
+    #[test]
+    fn test_decode_ssz_bool() {
+        let ssz = vec![0b0000_0000, 0b1000_0000];
+        let (result, index): (bool, usize) = decode_ssz(&ssz, 0).unwrap();
+        assert_eq!(index, 1);
+        assert_eq!(result, false);
+
+        let (result, index): (bool, usize) = decode_ssz(&ssz, 1).unwrap();
+        assert_eq!(index, 2);
+        assert_eq!(result, true);
+
+        let ssz = vec![0b0100_0000];
+        let result: Result<(bool, usize), DecodeError> = decode_ssz(&ssz, 0);
+        assert_eq!(result, Err(DecodeError::Invalid));
+    }
 }

eth2/utils/ssz/src/impl_encode.rs

@@ -46,6 +46,13 @@ impl_encodable_for_uint!(u32, 32);
 impl_encodable_for_uint!(u64, 64);
 impl_encodable_for_uint!(usize, 64);
 
+impl Encodable for bool {
+    fn ssz_append(&self, s: &mut SszStream) {
+        let byte = if *self { 0b1000_0000 } else { 0b0000_0000 };
+        s.append_encoded_raw(&[byte]);
+    }
+}
+
 impl Encodable for H256 {
     fn ssz_append(&self, s: &mut SszStream) {
         s.append_encoded_raw(&self.to_vec());
@@ -206,4 +213,17 @@ mod tests {
         ssz.append(&x);
         assert_eq!(ssz.drain(), vec![255, 255, 255, 255, 255, 255, 255, 255]);
     }
+
+    #[test]
+    fn test_ssz_encode_bool() {
+        let x: bool = false;
+        let mut ssz = SszStream::new();
+        ssz.append(&x);
+        assert_eq!(ssz.drain(), vec![0b0000_0000]);
+
+        let x: bool = true;
+        let mut ssz = SszStream::new();
+        ssz.append(&x);
+        assert_eq!(ssz.drain(), vec![0b1000_0000]);
+    }
 }

eth2/utils/ssz/src/impl_tree_hash.rs

@@ -3,49 +3,49 @@ use super::{merkle_hash, ssz_encode, TreeHash};
 use hashing::hash;
 
 impl TreeHash for u8 {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)
     }
 }
 
 impl TreeHash for u16 {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)
     }
 }
 
 impl TreeHash for u32 {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)
     }
 }
 
 impl TreeHash for u64 {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)
     }
 }
 
 impl TreeHash for usize {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)
     }
 }
 
 impl TreeHash for Address {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)
     }
 }
 
 impl TreeHash for H256 {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         ssz_encode(self)
     }
 }
 
 impl TreeHash for [u8] {
-    fn hash_tree_root(&self) -> Vec<u8> {
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
         if self.len() > 32 {
             return hash(&self);
         }
@@ -57,12 +57,12 @@ impl<T> TreeHash for Vec<T>
 where
     T: TreeHash,
 {
-    /// Returns the merkle_hash of a list of hash_tree_root values created
+    /// Returns the merkle_hash of a list of hash_tree_root_internal values created
     /// from the given list.
     /// Note: A byte vector, Vec<u8>, must be converted to a slice (as_slice())
     ///       to be handled properly (i.e. hashed) as byte array.
-    fn hash_tree_root(&self) -> Vec<u8> {
-        let mut tree_hashes = self.iter().map(|x| x.hash_tree_root()).collect();
+    fn hash_tree_root_internal(&self) -> Vec<u8> {
+        let mut tree_hashes = self.iter().map(|x| x.hash_tree_root_internal()).collect();
         merkle_hash(&mut tree_hashes)
     }
 }
@@ -73,7 +73,7 @@ mod tests {
 
     #[test]
     fn test_impl_tree_hash_vec() {
-        let result = vec![1u32, 2, 3, 4, 5, 6, 7].hash_tree_root();
+        let result = vec![1u32, 2, 3, 4, 5, 6, 7].hash_tree_root_internal();
         assert_eq!(result.len(), 32);
     }
 }

eth2/utils/ssz/src/tree_hash.rs

@@ -4,7 +4,14 @@ const SSZ_CHUNK_SIZE: usize = 128;
 const HASHSIZE: usize = 32;
 
 pub trait TreeHash {
-    fn hash_tree_root(&self) -> Vec<u8>;
+    fn hash_tree_root_internal(&self) -> Vec<u8>;
+    fn hash_tree_root(&self) -> Vec<u8> {
+        let mut result = self.hash_tree_root_internal();
+        if result.len() < HASHSIZE {
+            zpad(&mut result, HASHSIZE);
+        }
+        result
+    }
 }
 
 /// Returns a 32 byte hash of 'list' - a vector of byte vectors.
@@ -14,7 +21,8 @@ pub fn merkle_hash(list: &mut Vec<Vec<u8>>) -> Vec<u8> {
     let (mut chunk_size, mut chunkz) = list_to_blob(list);
 
     // get data_len as bytes. It will hashed will the merkle root
-    let datalen = list.len().to_le_bytes();
+    let mut datalen = list.len().to_le_bytes().to_vec();
+    zpad(&mut datalen, 32);
 
     // Tree-hash
     while chunkz.len() > HASHSIZE {
@@ -36,33 +44,68 @@ pub fn merkle_hash(list: &mut Vec<Vec<u8>>) -> Vec<u8> {
         chunkz = new_chunkz;
     }
 
-    chunkz.append(&mut datalen.to_vec());
+    chunkz.append(&mut datalen);
     hash(&chunkz)
 }
 
 fn list_to_blob(list: &mut Vec<Vec<u8>>) -> (usize, Vec<u8>) {
-    let chunk_size = if list.is_empty() {
+    let chunk_size = if list.is_empty() || list[0].len() < SSZ_CHUNK_SIZE {
         SSZ_CHUNK_SIZE
-    } else if list[0].len() < SSZ_CHUNK_SIZE {
-        let items_per_chunk = SSZ_CHUNK_SIZE / list[0].len();
-        items_per_chunk * list[0].len()
     } else {
         list[0].len()
     };
 
-    let mut data = Vec::new();
+    let (items_per_chunk, chunk_count) = if list.is_empty() {
+        (1, 1)
+    } else {
+        let items_per_chunk = SSZ_CHUNK_SIZE / list[0].len();
+        let chunk_count = list.len() / items_per_chunk;
+        (items_per_chunk, chunk_count)
+    };
+
+    let mut chunkz = Vec::new();
     if list.is_empty() {
         // handle and empty list
-        data.append(&mut vec![0; SSZ_CHUNK_SIZE]);
-    } else {
+        chunkz.append(&mut vec![0; SSZ_CHUNK_SIZE]);
+    } else if list[0].len() <= SSZ_CHUNK_SIZE {
         // just create a blob here; we'll divide into
         // chunked slices when we merklize
-        data.reserve(list[0].len() * list.len());
+        let mut chunk = Vec::with_capacity(chunk_size);
+        let mut item_count_in_chunk = 0;
+        chunkz.reserve(chunk_count * chunk_size);
         for item in list.iter_mut() {
-            data.append(item);
+            item_count_in_chunk += 1;
+            chunk.append(item);
+
+            // completed chunk?
+            if item_count_in_chunk == items_per_chunk {
+                zpad(&mut chunk, chunk_size);
+                chunkz.append(&mut chunk);
+                item_count_in_chunk = 0;
             }
         }
-    (chunk_size, data)
+
+        // left-over uncompleted chunk?
+        if item_count_in_chunk != 0 {
+            zpad(&mut chunk, chunk_size);
+            chunkz.append(&mut chunk);
+        }
+    } else {
+        // chunks larger than SSZ_CHUNK_SIZE
+        chunkz.reserve(chunk_count * chunk_size);
+        for item in list.iter_mut() {
+            chunkz.append(item);
+        }
+    }
+
+    (chunk_size, chunkz)
+}
+
+/// right pads with zeros making 'bytes' 'size' in length
+fn zpad(bytes: &mut Vec<u8>, size: usize) {
+    if bytes.len() < size {
+        bytes.resize(size, 0);
+    }
 }
 
 #[cfg(test)]

eth2/utils/ssz_derive/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "ssz_derive"
+version = "0.1.0"
+authors = ["Paul Hauner <paul@paulhauner.com>"]
+edition = "2018"
+description = "Procedural derive macros for SSZ encoding and decoding."
+
+[lib]
+proc-macro = true
+
+[dependencies]
+syn = "0.15"
+quote = "0.6"
+ssz = { path = "../ssz" }

eth2/utils/ssz_derive/src/lib.rs

@@ -0,0 +1,128 @@
+//! Provides the following procedural derive macros:
+//!
+//! - `#[derive(Encode)]`
+//! - `#[derive(Decode)]`
+//!
+//! These macros provide SSZ encoding/decoding for a `struct`. Fields are encoded/decoded in the
+//! order they are defined.
+//!
+//! Presently, only `structs` with named fields are supported. `enum`s and tuple-structs are
+//! unsupported.
+//!
+//! Example:
+//! ```
+//! use ssz::{ssz_encode, Decodable};
+//! use ssz_derive::{Encode, Decode};
+//!
+//! #[derive(Encode, Decode)]
+//! struct Foo {
+//!     pub bar: bool,
+//!     pub baz: u64,
+//! }
+//!
+//! fn main() {
+//!     let foo = Foo {
+//!         bar: true,
+//!         baz: 42,
+//!     };
+//!
+//!     let bytes = ssz_encode(&foo);
+//!
+//!     let (decoded_foo, _i) = Foo::ssz_decode(&bytes, 0).unwrap();
+//!
+//!     assert_eq!(foo.baz, decoded_foo.baz);
+//! }
+//! ```
+
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{parse_macro_input, DeriveInput};
+
+/// Returns a Vec of `syn::Ident` for each named field in the struct.
+///
+/// # Panics
+/// Any unnamed struct field (like in a tuple struct) will raise a panic at compile time.
+fn get_named_field_idents<'a>(struct_data: &'a syn::DataStruct) -> Vec<&'a syn::Ident> {
+    struct_data
+        .fields
+        .iter()
+        .map(|f| match &f.ident {
+            Some(ref ident) => ident,
+            _ => panic!("ssz_derive only supports named struct fields."),
+        })
+        .collect()
+}
+
+/// Implements `ssz::Encodable` for some `struct`.
+///
+/// Fields are encoded in the order they are defined.
+#[proc_macro_derive(Encode)]
+pub fn ssz_encode_derive(input: TokenStream) -> TokenStream {
+    let item = parse_macro_input!(input as DeriveInput);
+
+    let name = &item.ident;
+
+    let struct_data = match &item.data {
+        syn::Data::Struct(s) => s,
+        _ => panic!("ssz_derive only supports structs."),
+    };
+
+    let field_idents = get_named_field_idents(&struct_data);
+
+    let output = quote! {
+        impl ssz::Encodable for #name {
+            fn ssz_append(&self, s: &mut ssz::SszStream) {
+                #(
+                    s.append(&self.#field_idents);
+                )*
+            }
+        }
+    };
+    output.into()
+}
+
+/// Implements `ssz::Decodable` for some `struct`.
+///
+/// Fields are decoded in the order they are defined.
+#[proc_macro_derive(Decode)]
+pub fn ssz_decode_derive(input: TokenStream) -> TokenStream {
+    let item = parse_macro_input!(input as DeriveInput);
+
+    let name = &item.ident;
+
+    let struct_data = match &item.data {
+        syn::Data::Struct(s) => s,
+        _ => panic!("ssz_derive only supports structs."),
+    };
+
+    let field_idents = get_named_field_idents(&struct_data);
+
+    // Using a var in an iteration always consumes the var, therefore we must make a `fields_a` and
+    // a `fields_b` in order to perform two loops.
+    //
+    // https://github.com/dtolnay/quote/issues/8
+    let field_idents_a = &field_idents;
+    let field_idents_b = &field_idents;
+
+    let output = quote! {
+        impl ssz::Decodable for #name {
+            fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), ssz::DecodeError> {
+                #(
+                    let (#field_idents_a, i) = <_>::ssz_decode(bytes, i)?;
+                )*
+
+                Ok((
+                    Self {
+                        #(
+                            #field_idents_b,
+                        )*
+                    },
+                    i
+                ))
+            }
+        }
+    };
+    output.into()
+}

validator_client/Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Paul Hauner <paul@paulhauner.com>"]
 edition = "2018"
 
 [dependencies]
-block_producer = { path = "../eth2/block_producer" }
+block_proposer = { path = "../eth2/block_proposer" }
 bls = { path = "../eth2/utils/bls" }
 clap = "2.32.0"
 dirs = "1.0.3"

validator_client/src/block_producer_service/beacon_block_grpc_client.rs

@@ -1,4 +1,4 @@
-use block_producer::{BeaconNode, BeaconNodeError, PublishOutcome};
+use block_proposer::{BeaconNode, BeaconNodeError, PublishOutcome};
 use protos::services::{
     BeaconBlock as GrpcBeaconBlock, ProduceBeaconBlockRequest, PublishBeaconBlockRequest,
 };

validator_client/src/block_producer_service/mod.rs

@@ -1,7 +1,7 @@
 mod beacon_block_grpc_client;
 // mod block_producer_service;
 
-use block_producer::{
+use block_proposer::{
     BeaconNode, BlockProducer, DutiesReader, PollOutcome as BlockProducerPollOutcome, Signer,
 };
 use slog::{error, info, warn, Logger};

validator_client/src/duties/epoch_duties.rs

@@ -1,4 +1,4 @@
-use block_producer::{DutiesReader, DutiesReaderError};
+use block_proposer::{DutiesReader, DutiesReaderError};
 use std::collections::HashMap;
 use std::sync::RwLock;
 use types::{Epoch, Slot};

validator_client/src/main.rs

@@ -1,7 +1,7 @@
 use self::block_producer_service::{BeaconBlockGrpcClient, BlockProducerService};
 use self::duties::{DutiesManager, DutiesManagerService, EpochDutiesMap};
 use crate::config::ClientConfig;
-use block_producer::{test_utils::LocalSigner, BlockProducer};
+use block_proposer::{test_utils::LocalSigner, BlockProducer};
 use bls::Keypair;
 use clap::{App, Arg};
 use grpcio::{ChannelBuilder, EnvBuilder};