Create CompactSize64 for non-message-length fields

book/src/dev/rfcs/0010-v5-transaction.md

@@ -53,7 +53,7 @@ Orchard uses `Halo2Proof`s with corresponding signature type changes. Each Orcha
 [other-transaction-v5-changes]: #other-transaction-v5-changes
 
 V5 transactions split `Spend`s, `Output`s, and `AuthorizedAction`s into multiple arrays,
-with a single `compactsize` count before the first array. We add new
+with a single `CompactSize` count before the first array. We add new
 `zcash_deserialize_external_count` and `zcash_serialize_external_count` utility functions,
 which make it easier to serialize and deserialize these arrays correctly.
 

zebra-chain/src/serialization.rs

@@ -6,6 +6,7 @@
 //! `ReadZcashExt`, extension traits for `io::Read` and `io::Write` with utility functions
 //! for reading and writing data (e.g., the Bitcoin variable-integer format).
 
+mod compact_size;
 mod constraint;
 mod date_time;
 mod error;
@@ -14,13 +15,17 @@ mod write_zcash;
 mod zcash_deserialize;
 mod zcash_serialize;
 
-pub(crate) mod serde_helpers;
-
 pub mod sha256d;
 
+pub(crate) mod serde_helpers;
+
 #[cfg(any(test, feature = "proptest-impl"))]
 pub mod arbitrary;
 
+#[cfg(test)]
+pub mod tests;
+
+pub use compact_size::{CompactSize64, CompactSizeMessage};
 pub use constraint::AtLeastOne;
 pub use date_time::{DateTime32, Duration32};
 pub use error::SerializationError;
@@ -31,9 +36,6 @@ pub use zcash_deserialize::{
     ZcashDeserialize, ZcashDeserializeInto,
 };
 pub use zcash_serialize::{
-    zcash_serialize_bytes, zcash_serialize_bytes_external_count, zcash_serialize_external_count,
-    FakeWriter, ZcashSerialize, MAX_PROTOCOL_MESSAGE_LEN,
+    zcash_serialize_bytes, zcash_serialize_bytes_external_count, zcash_serialize_empty_list,
+    zcash_serialize_external_count, FakeWriter, ZcashSerialize, MAX_PROTOCOL_MESSAGE_LEN,
 };
-
-#[cfg(test)]
-pub mod tests;

zebra-chain/src/serialization/arbitrary.rs

@@ -1,9 +1,13 @@
 //! Arbitrary data generation for serialization proptests
 
-use super::{read_zcash::canonical_socket_addr, DateTime32};
+use std::{convert::TryInto, net::SocketAddr};
+
 use chrono::{TimeZone, Utc, MAX_DATETIME, MIN_DATETIME};
 use proptest::{arbitrary::any, prelude::*};
-use std::net::SocketAddr;
+
+use super::{
+    read_zcash::canonical_socket_addr, CompactSizeMessage, DateTime32, MAX_PROTOCOL_MESSAGE_LEN,
+};
 
 impl Arbitrary for DateTime32 {
     type Parameters = ();
@@ -62,3 +66,18 @@ pub fn datetime_u32() -> impl Strategy<Value = chrono::DateTime<Utc>> {
 pub fn canonical_socket_addr_strategy() -> impl Strategy<Value = SocketAddr> {
     any::<SocketAddr>().prop_map(canonical_socket_addr)
 }
+
+impl Arbitrary for CompactSizeMessage {
+    type Parameters = ();
+
+    fn arbitrary_with(_args: Self::Parameters) -> Self::Strategy {
+        (0..=MAX_PROTOCOL_MESSAGE_LEN)
+            .prop_map(|size| {
+                size.try_into()
+                    .expect("MAX_PROTOCOL_MESSAGE_LEN fits in CompactSizeMessage")
+            })
+            .boxed()
+    }
+
+    type Strategy = BoxedStrategy<Self>;
+}