Rename fork_choice_2 to lmd_ghost

Cargo.toml

@@ -1,7 +1,7 @@
 [workspace]
 members = [
 	"eth2/fork_choice",
-	"eth2/fork_choice_2",
+	"eth2/lmd_ghost",
 	"eth2/operation_pool",
 	"eth2/state_processing",
 	"eth2/types",

eth2/fork_choice_2/src/lib.rs

@@ -1,36 +0,0 @@
-pub mod reduced_tree;
-
-use std::sync::Arc;
-use types::{Hash256, Slot};
-
-type Result<T> = std::result::Result<T, Error>;
-
-#[derive(Debug, PartialEq)]
-pub enum Error {
-    BackendError(String),
-}
-
-pub trait LmdGhostBackend<T>: Send + Sync {
-    fn new(store: Arc<T>) -> Self;
-
-    fn process_message(
-        &self,
-        validator_index: usize,
-        block_hash: Hash256,
-        block_slot: Slot,
-    ) -> Result<()>;
-
-    fn find_head(&self) -> Result<Hash256>;
-}
-
-pub struct ForkChoice<T> {
-    algorithm: T,
-}
-
-impl<T: LmdGhostBackend<T>> ForkChoice<T> {
-    pub fn new(store: Arc<T>) -> Self {
-        Self {
-            algorithm: T::new(store),
-        }
-    }
-}

eth2/lmd_ghost/Cargo.toml

@@ -1,19 +1,20 @@
 [package]
-name = "fork_choice_2"
+name = "lmd_ghost"
 version = "0.1.0"
 authors = ["Age Manning <Age@AgeManning.com>", "Paul Hauner <paul@sigmaprime.io>"]
 edition = "2018"
 
 [dependencies]
+parking_lot = "0.7"
 store = { path = "../../beacon_node/store" }
 ssz = { path = "../utils/ssz" }
+state_processing = { path = "../state_processing" }
 types = { path = "../types" }
 log = "0.4.6"
 bit-vec = "0.5.0"
 
 [dev-dependencies]
 criterion = "0.2"
-parking_lot = "0.7"
 hex = "0.3.2"
 yaml-rust = "0.4.2"
 bls = { path = "../utils/bls" }

eth2/lmd_ghost/src/lib.rs

@@ -0,0 +1,99 @@
+pub mod reduced_tree;
+
+use state_processing::common::get_attesting_indices_unsorted;
+use std::marker::PhantomData;
+use std::sync::Arc;
+use types::{Attestation, BeaconBlock, BeaconState, BeaconStateError, EthSpec, Hash256, Slot};
+
+type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Debug, PartialEq)]
+pub enum Error {
+    BackendError(String),
+    BeaconStateError(BeaconStateError),
+}
+
+pub trait LmdGhostBackend<T, E: EthSpec>: Send + Sync {
+    fn new(store: Arc<T>) -> Self;
+
+    fn process_message(
+        &self,
+        validator_index: usize,
+        block_hash: Hash256,
+        block_slot: Slot,
+    ) -> Result<()>;
+
+    fn find_head(&self) -> Result<Hash256>;
+}
+
+pub struct ForkChoice<T, E> {
+    backend: T,
+    _phantom: PhantomData<E>,
+}
+
+impl<T, E> ForkChoice<T, E>
+where
+    T: LmdGhostBackend<T, E>,
+    E: EthSpec,
+{
+    pub fn new(store: Arc<T>) -> Self {
+        Self {
+            backend: T::new(store),
+            _phantom: PhantomData,
+        }
+    }
+
+    pub fn find_head(&self) -> Result<Hash256> {
+        self.backend.find_head()
+    }
+
+    pub fn process_attestation(
+        &self,
+        state: &BeaconState<E>,
+        attestation: &Attestation,
+    ) -> Result<()> {
+        let validator_indices = get_attesting_indices_unsorted(
+            state,
+            &attestation.data,
+            &attestation.aggregation_bitfield,
+        )?;
+
+        let block_hash = attestation.data.target_root;
+
+        // TODO: what happens when the target root is not the same slot as the block?
+        let block_slot = attestation
+            .data
+            .target_epoch
+            .start_slot(E::slots_per_epoch());
+
+        for validator_index in validator_indices {
+            self.backend
+                .process_message(validator_index, block_hash, block_slot)?;
+        }
+
+        Ok(())
+    }
+
+    pub fn process_block(
+        &self,
+        state: &BeaconState<E>,
+        block: &BeaconBlock,
+        block_hash: Hash256,
+        block_proposer: usize,
+    ) -> Result<()> {
+        self.backend
+            .process_message(block_proposer, block_hash, block.slot)?;
+
+        for attestation in &block.body.attestations {
+            self.process_attestation(state, attestation)?;
+        }
+
+        Ok(())
+    }
+}
+
+impl From<BeaconStateError> for Error {
+    fn from(e: BeaconStateError) -> Error {
+        Error::BeaconStateError(e)
+    }
+}

eth2/lmd_ghost/src/reduced_tree.rs

@@ -69,7 +69,7 @@ pub struct Vote {
     slot: Slot,
 }
 
-impl<T, E> LmdGhostBackend<T> for ThreadSafeReducedTree<T, E>
+impl<T, E> LmdGhostBackend<T, E> for ThreadSafeReducedTree<T, E>
 where
     T: Store,
     E: EthSpec,