From 2d6cb93125cd58e66a42f27d2a62732144514c07 Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@z.cash>
Date: Thu, 31 Mar 2022 15:08:09 +0000
Subject: [PATCH] wallet: Add version information to Orchard commitment tree
 data

We add both C++ client version information (enabling version-specific
changes if necessary, matching the rest of the C++ wallet), and record
version information (enabling local serialization format changes).

Part of zcash/zcash#5784.
---
 src/rust/src/wallet.rs | 33 +++++++++++++++++++++++++++------
 src/wallet/orchard.h   |  8 ++++++++
 2 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/src/rust/src/wallet.rs b/src/rust/src/wallet.rs
index 7473b0462..21316d6df 100644
--- a/src/rust/src/wallet.rs
+++ b/src/rust/src/wallet.rs
@@ -1177,6 +1177,8 @@ pub extern "C" fn orchard_wallet_gc_note_commitment_tree(wallet: *mut Wallet) {
     wallet.witness_tree.garbage_collect();
 }
 
+const NOTE_STATE_V1: u8 = 1;
+
 #[no_mangle]
 pub extern "C" fn orchard_wallet_write_note_commitment_tree(
     wallet: *const Wallet,
@@ -1186,7 +1188,7 @@ pub extern "C" fn orchard_wallet_write_note_commitment_tree(
     let wallet = unsafe { wallet.as_ref() }.expect("Wallet pointer may not be null.");
     let mut writer = CppStreamWriter::from_raw_parts(stream, write_cb.unwrap());
 
-    let mut write_all = move || -> io::Result<()> {
+    let write_v1 = move |mut writer: CppStreamWriter| -> io::Result<()> {
         Optional::write(&mut writer, wallet.last_checkpoint, |w, h| {
             w.write_u32::<LittleEndian>(h.into())
         })?;
@@ -1212,7 +1214,10 @@ pub extern "C" fn orchard_wallet_write_note_commitment_tree(
         Ok(())
     };
 
-    match write_all() {
+    match writer
+        .write_u8(NOTE_STATE_V1)
+        .and_then(|()| write_v1(writer))
+    {
         Ok(()) => true,
         Err(e) => {
             error!("Failure in writing Orchard note commitment tree: {}", e);
@@ -1230,7 +1235,7 @@ pub extern "C" fn orchard_wallet_load_note_commitment_tree(
     let wallet = unsafe { wallet.as_mut() }.expect("Wallet pointer may not be null.");
     let mut reader = CppStreamReader::from_raw_parts(stream, read_cb.unwrap());
 
-    let mut read_all = move || -> io::Result<()> {
+    let mut read_v1 = move |mut reader: CppStreamReader| -> io::Result<()> {
         let last_checkpoint = Optional::read(&mut reader, |r| {
             r.read_u32::<LittleEndian>().map(BlockHeight::from)
         })?;
@@ -1257,14 +1262,30 @@ pub extern "C" fn orchard_wallet_load_note_commitment_tree(
         Ok(())
     };
 
-    match read_all() {
-        Ok(_) => true,
+    match reader.read_u8() {
         Err(e) => {
             error!(
-                "Failed to read Orchard note commitment or last checkpoint height: {}",
+                "Failed to read Orchard note position serialization flag: {}",
                 e
             );
             false
         }
+        Ok(NOTE_STATE_V1) => match read_v1(reader) {
+            Ok(_) => true,
+            Err(e) => {
+                error!(
+                    "Failed to read Orchard note commitment or last checkpoint height: {}",
+                    e
+                );
+                false
+            }
+        },
+        Ok(flag) => {
+            error!(
+                "Unrecognized Orchard note position serialization version: {}",
+                flag
+            );
+            false
+        }
     }
 }
diff --git a/src/wallet/orchard.h b/src/wallet/orchard.h
index 45e5a3ab4..5019c4d4e 100644
--- a/src/wallet/orchard.h
+++ b/src/wallet/orchard.h
@@ -485,6 +485,10 @@ public:
 
     template<typename Stream>
     void Serialize(Stream& s) const {
+        int nVersion = s.GetVersion();
+        if (!(s.GetType() & SER_GETHASH)) {
+            ::Serialize(s, nVersion);
+        }
         RustStream rs(s);
         if (!orchard_wallet_write_note_commitment_tree(
                     wallet.inner.get(),
@@ -503,6 +507,10 @@ public:
 
     template<typename Stream>
     void Unserialize(Stream& s) {
+        int nVersion = s.GetVersion();
+        if (!(s.GetType() & SER_GETHASH)) {
+            ::Unserialize(s, nVersion);
+        }
         RustStream rs(s);
         if (!orchard_wallet_load_note_commitment_tree(
                     wallet.inner.get(),