Add attestion ssz splitter, change dir structure

lighthouse/state/attestation_record/attestation_record.rs

@@ -22,7 +22,7 @@ pub const MIN_SSZ_ATTESTION_RECORD_LENGTH: usize = {
     4 + BLS_AGG_SIG_BYTE_SIZE    // aggregate sig (two 256 bit points)
 };
 
-#[derive(Debug)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct AttestationRecord {
     pub slot: u64,
     pub shard_id: u16,

lighthouse/state/attestation_record/mod.rs

@@ -0,0 +1,17 @@
+use super::bls;
+use super::ssz;
+use super::utils;
+
+
+mod attestation_record;
+mod ssz_splitter;
+
+pub use self::attestation_record::{
+    AttestationRecord,
+    MIN_SSZ_ATTESTION_RECORD_LENGTH,
+};
+pub use self::ssz_splitter::{
+    split_all,
+    split_one,
+    AttestationSplitError,
+};

lighthouse/state/attestation_record/ssz_splitter.rs

@@ -0,0 +1,139 @@
+use super::MIN_SSZ_ATTESTION_RECORD_LENGTH as MIN_LENGTH;
+use super::ssz::LENGTH_BYTES;
+use super::ssz::decode::decode_length;
+
+#[derive(Debug, PartialEq)]
+pub enum AttestationSplitError {
+    TooShort,
+}
+
+/// Given some ssz slice, find the bounds of each serialized AttestationRecord and return a vec of
+/// slices point to each.
+pub fn split_all<'a>(full_ssz: &'a [u8], index: usize)
+    -> Result<Vec<&'a [u8]>, AttestationSplitError>
+{
+    let mut v = vec![];
+    let mut index = index;
+    while index < full_ssz.len() - 1 {
+        let (slice, i) = split_one(full_ssz, index)?;
+        v.push(slice);
+        index = i;
+    }
+    Ok(v)
+}
+
+/// Given some ssz slice, find the bounds of one serialized AttestationRecord
+/// and return a slice pointing to that.
+pub fn split_one<'a>(full_ssz: &'a [u8], index: usize)
+    -> Result<(&'a [u8], usize), AttestationSplitError>
+{
+    if full_ssz.len() < MIN_LENGTH {
+        return Err(AttestationSplitError::TooShort);
+    }
+
+    let hashes_len = decode_length(full_ssz, 10, LENGTH_BYTES)
+        .map_err(|_| AttestationSplitError::TooShort)?;
+
+    let bitfield_len = decode_length(
+        full_ssz, hashes_len + 46,
+        LENGTH_BYTES)
+        .map_err(|_| AttestationSplitError::TooShort)?;
+
+    // Subtract one because the min length assume 1 byte of bitfield
+    let len = MIN_LENGTH
+        + hashes_len
+        + bitfield_len.saturating_sub(1);
+
+    if full_ssz.len() < len {
+        return Err(AttestationSplitError::TooShort);
+    }
+
+    Ok((&full_ssz[index..(index + len)], index + len))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use super::super::AttestationRecord;
+    use super::super::utils::types::{
+        Hash256,
+        Bitfield,
+    };
+    use super::super::bls::AggregateSignature;
+    use super::super::ssz::{
+        SszStream,
+        Decodable,
+    };
+
+    fn get_two_records() -> Vec<AttestationRecord> {
+        let a = AttestationRecord {
+            slot: 7,
+            shard_id: 9,
+            oblique_parent_hashes: vec![Hash256::from(&vec![14; 32][..])],
+            shard_block_hash: Hash256::from(&vec![15; 32][..]),
+            attester_bitfield: Bitfield::from(&vec![17; 42][..]),
+            justified_slot: 19,
+            justified_block_hash: Hash256::from(&vec![15; 32][..]),
+            aggregate_sig: AggregateSignature::new(),
+        };
+        let b = AttestationRecord {
+            slot: 9,
+            shard_id: 7,
+            oblique_parent_hashes: vec![Hash256::from(&vec![15; 32][..])],
+            shard_block_hash: Hash256::from(&vec![14; 32][..]),
+            attester_bitfield: Bitfield::from(&vec![19; 42][..]),
+            justified_slot: 15,
+            justified_block_hash: Hash256::from(&vec![17; 32][..]),
+            aggregate_sig: AggregateSignature::new(),
+        };
+        vec![a, b]
+    }
+
+    #[test]
+    fn test_attestation_ssz_split() {
+        let ars = get_two_records();
+        let a = ars[0].clone();
+        let b = ars[1].clone();
+
+
+        /*
+         * Test split one
+         */
+        let mut ssz_stream = SszStream::new();
+        ssz_stream.append(&a);
+        let ssz = ssz_stream.drain();
+        let (a_ssz, i) = split_one(&ssz, 0).unwrap();
+        assert_eq!(i, ssz.len());
+        let (decoded_a, _) = AttestationRecord::ssz_decode(a_ssz, 0)
+            .unwrap();
+        assert_eq!(a, decoded_a);
+
+        /*
+         * Test split two
+         */
+        let mut ssz_stream = SszStream::new();
+        ssz_stream.append(&a);
+        ssz_stream.append(&b);
+        let ssz = ssz_stream.drain();
+        let ssz_vec = split_all(&ssz, 0).unwrap();
+        let (decoded_a, _) =
+            AttestationRecord::ssz_decode(ssz_vec[0], 0)
+            .unwrap();
+        let (decoded_b, _) =
+            AttestationRecord::ssz_decode(ssz_vec[1], 0)
+            .unwrap();
+        assert_eq!(a, decoded_a);
+        assert_eq!(b, decoded_b);
+
+        /*
+         * Test split two with shortened ssz
+         */
+        let mut ssz_stream = SszStream::new();
+        ssz_stream.append(&a);
+        ssz_stream.append(&b);
+        let ssz = ssz_stream.drain();
+        let ssz = &ssz[0..ssz.len() - 1];
+        assert!(split_all(&ssz, 0).is_err());
+    }
+}
+

lighthouse/state/block/ssz_block.rs

@@ -13,9 +13,6 @@ use super::attestation_record::MIN_SSZ_ATTESTION_RECORD_LENGTH;
 pub enum BlockValidatorError {
     TooShort,
     TooLong,
-    BadPowHash,
-    SlotTooLow,
-    SlotTooHigh,
 }
 
 const LENGTH_BYTES: usize = 4;
@@ -23,7 +20,7 @@ const LENGTH_BYTES: usize = 4;
 /// Allows for reading of block values directly from serialized ssz bytes.
 ///
 /// The purpose of this struct is to provide the functionality to read block fields directly from
-/// some serialized SSZ slice, effectively allowing us to read the block without fully
+/// some serialized SSZ slice allowing us to read the block without fully
 /// de-serializing it.
 ///
 /// This struct should be as "zero-copy" as possible. The `ssz` field is a reference to some slice

lighthouse/state/validation/attestation/attestation_validation.rs

@@ -52,6 +52,11 @@ fn bytes_for_bits(bits: usize) -> usize {
     (bits.saturating_sub(1) / 8) + 1
 }
 
+fn any_of_last_n_bits_are_set(byte: &u8, n: usize) -> bool {
+    let shift = 8_u8.saturating_sub(n as u8);
+    ((!0 >> shift) & byte) > 0
+}
+
 pub fn validate_attestation<T>(a: &AttestationRecord,
                                block_slot: u64,
                                cycle_length: u8,
@@ -162,11 +167,6 @@ pub fn validate_attestation<T>(a: &AttestationRecord,
     Ok((signature_valid, voted_hashmap))
 }
 
-fn any_of_last_n_bits_are_set(byte: &u8, n: usize) -> bool {
-    let shift = 8_u8.saturating_sub(n as u8);
-    ((!0 >> shift) & byte) > 0
-}
-
 /// Generates the message used to validate the signature provided with an AttestationRecord.
 ///
 /// Ensures that the signer of the message has a view of the chain that is compatible with ours.

lighthouse/state/validation/attestation/mod.rs

@@ -0,0 +1,11 @@
+use super::db;
+use super::bls;
+use super::AttestationRecord;
+use super::ssz;
+use super::attestation_parent_hashes;
+use super::utils;
+
+mod attestation_validation;
+mod signatures;
+
+pub use self::attestation_validation::validate_attestation;

lighthouse/state/validation/mod.rs

@@ -14,6 +14,5 @@ use super::ssz;
 use super::transition::attestation_parent_hashes;
 use super::utils;
 
-mod attestation_validation;
-mod signatures;
+mod attestation;
 mod ssz_block;

lighthouse/state/validator_record.rs

@@ -3,8 +3,6 @@ extern crate rand;
 use super::utils::types::{ Hash256, Address, U256 };
 use super::bls::{ PublicKey, Keypair };
 
-use self::rand::thread_rng;
-
 pub struct ValidatorRecord {
     pub pubkey: PublicKey,
     pub withdrawal_shard: u16,