Allow downloading of large tests from EF github and fix issues with serde

eth2/utils/bls/src/aggregate_signature.rs

@@ -1,30 +1,39 @@
-use super::{AggregatePublicKey, Signature};
+use super::{AggregatePublicKey, Signature, BLS_AGG_SIG_BYTE_SIZE};
 use bls_aggregates::{
     AggregatePublicKey as RawAggregatePublicKey, AggregateSignature as RawAggregateSignature,
 };
 use serde::de::{Deserialize, Deserializer};
 use serde::ser::{Serialize, Serializer};
 use serde_hex::{encode as hex_encode, PrefixedHexVisitor};
-use ssz::{
-    decode_ssz_list, hash, ssz_encode, Decodable, DecodeError, Encodable, SszStream, TreeHash,
-};
+use ssz::{decode_ssz_list, hash, Decodable, DecodeError, Encodable, SszStream, TreeHash};
 
 /// A BLS aggregate signature.
 ///
 /// This struct is a wrapper upon a base type and provides helper functions (e.g., SSZ
 /// serialization).
 #[derive(Debug, PartialEq, Clone, Default, Eq)]
-pub struct AggregateSignature(RawAggregateSignature);
+pub struct AggregateSignature {
+    aggregate_signature: RawAggregateSignature,
+    is_empty: bool,
+}
 
 impl AggregateSignature {
     /// Instantiate a new AggregateSignature.
+    ///
+    /// is_empty is false
+    /// AggregateSiganture is point at infinity
     pub fn new() -> Self {
-        AggregateSignature(RawAggregateSignature::new())
+        Self {
+            aggregate_signature: RawAggregateSignature::new(),
+            is_empty: false,
+        }
     }
 
     /// Add (aggregate) a signature to the `AggregateSignature`.
     pub fn add(&mut self, signature: &Signature) {
-        self.0.add(signature.as_raw())
+        if !self.is_empty {
+            self.aggregate_signature.add(signature.as_raw())
+        }
     }
 
     /// Verify the `AggregateSignature` against an `AggregatePublicKey`.
@@ -37,7 +46,11 @@ impl AggregateSignature {
         domain: u64,
         aggregate_public_key: &AggregatePublicKey,
     ) -> bool {
-        self.0.verify(msg, domain, aggregate_public_key.as_raw())
+        if self.is_empty {
+            return false;
+        }
+        self.aggregate_signature
+            .verify(msg, domain, aggregate_public_key.as_raw())
     }
 
     /// Verify this AggregateSignature against multiple AggregatePublickeys with multiple Messages.
@@ -50,6 +63,9 @@ impl AggregateSignature {
         domain: u64,
         aggregate_public_keys: &[&AggregatePublicKey],
     ) -> bool {
+        if self.is_empty {
+            return false;
+        }
         let aggregate_public_keys: Vec<&RawAggregatePublicKey> =
             aggregate_public_keys.iter().map(|pk| pk.as_raw()).collect();
 
@@ -59,14 +75,53 @@ impl AggregateSignature {
             msg.extend_from_slice(message);
         }
 
-        self.0
+        self.aggregate_signature
             .verify_multiple(&msg[..], domain, &aggregate_public_keys[..])
     }
+
+    /// Return AggregateSiganture as bytes
+    pub fn as_bytes(&self) -> Vec<u8> {
+        if self.is_empty {
+            return vec![0; BLS_AGG_SIG_BYTE_SIZE];
+        }
+        self.aggregate_signature.as_bytes()
+    }
+
+    /// Convert bytes to AggregateSiganture
+    pub fn from_bytes(bytes: &[u8]) -> Result<Self, DecodeError> {
+        for byte in bytes {
+            if *byte != 0 {
+                let sig =
+                    RawAggregateSignature::from_bytes(&bytes).map_err(|_| DecodeError::Invalid)?;
+                return Ok(Self {
+                    aggregate_signature: sig,
+                    is_empty: false,
+                });
+            }
+        }
+        Ok(Self::empty_signature())
+    }
+
+    /// Returns if the AggregateSiganture `is_empty`
+    pub fn is_empty(&self) -> bool {
+        self.is_empty
+    }
+
+    /// Creates a new AggregateSignature
+    ///
+    /// aggregate_signature set to the point infinity
+    /// is_empty set to true
+    pub fn empty_signature() -> Self {
+        Self {
+            aggregate_signature: RawAggregateSignature::new(),
+            is_empty: true,
+        }
+    }
 }
 
 impl Encodable for AggregateSignature {
     fn ssz_append(&self, s: &mut SszStream) {
-        s.append_vec(&self.0.as_bytes());
+        s.append_vec(&self.as_bytes());
     }
 }
 
@@ -74,35 +129,43 @@ impl Decodable for AggregateSignature {
     fn ssz_decode(bytes: &[u8], i: usize) -> Result<(Self, usize), DecodeError> {
         let (sig_bytes, i) = decode_ssz_list(bytes, i)?;
         let raw_sig =
-            RawAggregateSignature::from_bytes(&sig_bytes).map_err(|_| DecodeError::TooShort)?;
-        Ok((AggregateSignature(raw_sig), i))
+            RawAggregateSignature::from_bytes(&sig_bytes).map_err(|_| DecodeError::Invalid)?;
+        Ok((
+            Self {
+                aggregate_signature: raw_sig,
+                is_empty: false,
+            },
+            i,
+        ))
     }
 }
 
 impl Serialize for AggregateSignature {
+    /// Serde serialization is compliant the Ethereum YAML test format.
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
         S: Serializer,
     {
-        serializer.serialize_str(&hex_encode(ssz_encode(self)))
+        serializer.serialize_str(&hex_encode(self.as_bytes()))
     }
 }
 
 impl<'de> Deserialize<'de> for AggregateSignature {
+    /// Serde serialization is compliant the Ethereum YAML test format.
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
         D: Deserializer<'de>,
     {
         let bytes = deserializer.deserialize_str(PrefixedHexVisitor)?;
-        let (obj, _) = <_>::ssz_decode(&bytes[..], 0)
+        let agg_sig = AggregateSignature::from_bytes(&bytes[..])
             .map_err(|e| serde::de::Error::custom(format!("invalid ssz ({:?})", e)))?;
-        Ok(obj)
+        Ok(agg_sig)
     }
 }
 
 impl TreeHash for AggregateSignature {
     fn hash_tree_root(&self) -> Vec<u8> {
-        hash(&self.0.as_bytes())
+        hash(&self.as_bytes())
     }
 }