fix(rpc): using dedicated big-endian hex parser

Cargo.toml

@@ -93,6 +93,7 @@ zcash_protocol = "0.7"
 orchard = "0.11"
 sapling = { package = "sapling-crypto", version = "0.5" }
 transparent = { package = "zcash_transparent", version = "0.6" }
+zcash_encoding = "0.3.0"
 zcash_keys = { version = "0.12", features = ["transparent-inputs", "sapling", "orchard", "transparent-key-encoding"] }
 zcash_primitives = "0.26"
 zcash_proofs = "0.26"
@@ -135,6 +136,7 @@ anyhow = "1.0"
 tonic = "0.14"
 
 [patch.crates-io]
+zcash_encoding ={git = "https://github.com/distractedm1nd/librustzcash.git", rev = "cf39300ffa47aca9f2dec1f55727d17a5301f2fe", package = "zcash_encoding"}
 age = { git = "https://github.com/str4d/rage.git", rev = "92f437bc2a061312fa6633bb70c91eef91142fd4" }
 
 abscissa_core = { git = "https://github.com/iqlusioninc/abscissa.git", rev = "fdb60678fb3a883decf63d6d3ebc512abd20406f" }

zallet/Cargo.toml

@@ -143,6 +143,7 @@ uuid.workspace = true
 which = { workspace = true, optional = true }
 xdg.workspace = true
 zaino-common.workspace = true
+zcash_encoding.workspace = true
 zaino-fetch.workspace = true
 zaino-proto.workspace = true
 zaino-state.workspace = true

zallet/src/components/json_rpc/methods/get_raw_transaction.rs

@@ -5,6 +5,7 @@ use schemars::JsonSchema;
 use serde::Serialize;
 use transparent::bundle::{TxIn, TxOut};
 use zaino_state::{FetchServiceError, FetchServiceSubscriber, LightWalletIndexer, ZcashIndexer};
+use zcash_encoding::ReverseHex;
 use zcash_protocol::{
     TxId,
     consensus::{self, BlockHeight},
@@ -15,7 +16,7 @@ use crate::components::{
     database::DbConnection,
     json_rpc::{
         server::LegacyCode,
-        utils::{JsonZec, JsonZecBalance, parse_txid, value_from_zat_balance, value_from_zatoshis},
+        utils::{JsonZec, JsonZecBalance, value_from_zat_balance, value_from_zatoshis},
     },
 };
 
@@ -475,7 +476,7 @@ pub(crate) async fn call(
     verbose: Option<u64>,
     blockhash: Option<String>,
 ) -> Response {
-    let _txid = parse_txid(txid_str)?;
+    let _txid = TxId::from_bytes(ReverseHex::decode(txid_str).expect("valid txid"));
     let verbose = verbose.is_some_and(|v| v != 0);
 
     // TODO: We can't support this via the current Zaino API; wait for `ChainIndex`.
@@ -572,7 +573,7 @@ pub(crate) async fn call(
     let (vjoinsplit, join_split_pub_key, join_split_sig) = match tx.sprout_bundle() {
         Some(bundle) if !bundle.joinsplits.is_empty() => (
             bundle.joinsplits.iter().map(JoinSplit::encode).collect(),
-            Some(TxId::from_bytes(bundle.joinsplit_pubkey).to_string()),
+            Some(ReverseHex::decode(bundle.joinsplit_pubkey)),
             Some(hex::encode(bundle.joinsplit_sig)),
         ),
         _ => (vec![], None, None),
@@ -614,8 +615,7 @@ pub(crate) async fn call(
         in_active_chain: None,
         hex: tx_hex,
         txid: txid_str.to_ascii_lowercase(),
-        authdigest: TxId::from_bytes(tx.auth_commitment().as_bytes().try_into().unwrap())
-            .to_string(),
+        authdigest: ReverseHex::encode(&tx.auth_commitment().as_bytes().try_into().unwrap()),
         size,
         overwintered,
         version: tx.version().header() & 0x7FFFFFFF,
@@ -709,10 +709,10 @@ impl JoinSplit {
 impl SaplingSpend {
     fn encode(spend: &SpendDescription<sapling::bundle::Authorized>) -> Self {
         Self {
-            cv: TxId::from_bytes(spend.cv().to_bytes()).to_string(),
-            anchor: TxId::from_bytes(spend.anchor().to_bytes()).to_string(),
-            nullifier: TxId::from_bytes(spend.nullifier().0).to_string(),
-            rk: TxId::from_bytes(<[u8; 32]>::from(*spend.rk())).to_string(),
+            cv: ReverseHex::encode(&spend.cv().to_bytes()),
+            anchor: ReverseHex::encode(&spend.anchor().to_bytes()),
+            nullifier: ReverseHex::encode(&spend.nullifier().0),
+            rk: ReverseHex::encode(&<[u8; 32]>::from(*spend.rk())),
             proof: hex::encode(spend.zkproof()),
             spend_auth_sig: hex::encode(<[u8; 64]>::from(*spend.spend_auth_sig())),
         }
@@ -722,9 +722,9 @@ impl SaplingSpend {
 impl SaplingOutput {
     fn encode(output: &OutputDescription<sapling::bundle::GrothProofBytes>) -> Self {
         Self {
-            cv: TxId::from_bytes(output.cv().to_bytes()).to_string(),
-            cmu: TxId::from_bytes(output.cmu().to_bytes()).to_string(),
-            ephemeral_key: TxId::from_bytes(output.ephemeral_key().0).to_string(),
+            cv: ReverseHex::encode(&output.cv().to_bytes()),
+            cmu: ReverseHex::encode(&output.cmu().to_bytes()),
+            ephemeral_key: ReverseHex::encode(&output.ephemeral_key().0),
             enc_ciphertext: hex::encode(output.enc_ciphertext()),
             out_ciphertext: hex::encode(output.out_ciphertext()),
             proof: hex::encode(output.zkproof()),

zallet/src/components/json_rpc/methods/view_transaction.rs

@@ -15,6 +15,7 @@ use zcash_address::{
 };
 use zcash_client_backend::data_api::WalletRead;
 use zcash_client_sqlite::{AccountUuid, error::SqliteClientError};
+use zcash_encoding::ReverseHex;
 use zcash_keys::encoding::AddressCodec;
 use zcash_note_encryption::{try_note_decryption, try_output_recovery_with_ovk};
 use zcash_protocol::{
@@ -30,7 +31,7 @@ use crate::components::{
     database::DbConnection,
     json_rpc::{
         server::LegacyCode,
-        utils::{JsonZec, parse_txid, value_from_zatoshis},
+        utils::{JsonZec, value_from_zatoshis},
     },
 };
 
@@ -275,7 +276,7 @@ pub(crate) async fn call(
     chain: FetchServiceSubscriber,
     txid_str: &str,
 ) -> Response {
-    let txid = parse_txid(txid_str)?;
+    let txid = TxId::from_bytes(ReverseHex::decode(txid_str).expect("valid txid"));
 
     // Fetch this early so we can detect if the wallet is not ready yet.
     // TODO: Replace with Zaino `ChainIndex` so we can operate against a chain snapshot.

zallet/src/components/json_rpc/utils.rs

@@ -9,7 +9,6 @@ use schemars::{JsonSchema, json_schema};
 use serde::Serialize;
 use zcash_client_sqlite::AccountUuid;
 use zcash_protocol::{
-    TxId,
     consensus::BlockHeight,
     value::{COIN, ZatBalance, Zatoshis},
 };
@@ -43,16 +42,6 @@ pub(super) async fn ensure_wallet_is_unlocked(keystore: &KeyStore) -> RpcResult<
     }
 }
 
-// TODO: Move this to `zcash_protocol`.
-//       https://github.com/zcash/librustzcash/issues/1934
-pub(crate) fn parse_txid(txid_str: &str) -> RpcResult<TxId> {
-    let mut bytes = [0; 32];
-    hex::decode_to_slice(txid_str, &mut bytes)
-        .map_err(|_| LegacyCode::InvalidParameter.with_static("invalid txid"))?;
-    bytes.reverse();
-    Ok(TxId::from_bytes(bytes))
-}
-
 /// Parses the `seedfp` parameter present in many wallet RPCs.
 #[cfg(zallet_build = "wallet")]
 pub(super) fn parse_seedfp_parameter(seedfp: &str) -> RpcResult<SeedFingerprint> {

zallet/src/components/sync.rs

@@ -22,6 +22,7 @@ use zcash_client_backend::{
     scanning::ScanError,
     wallet::WalletTransparentOutput,
 };
+use zcash_encoding::ReverseHex;
 use zcash_keys::encoding::AddressCodec;
 use zcash_primitives::transaction::Transaction;
 use zcash_protocol::{
@@ -38,9 +39,7 @@ use super::{
     chain_view::ChainView,
     database::{Database, DbConnection},
 };
-use crate::{
-    components::json_rpc::utils::parse_txid, config::ZalletConfig, error::Error, network::Network,
-};
+use crate::{config::ZalletConfig, error::Error, network::Network};
 
 mod cache;
 
@@ -649,8 +648,10 @@ async fn data_requests(
                     };
 
                     for txid_str in chain.get_address_tx_ids(request).await? {
-                        let txid = parse_txid(&txid_str)
-                            .expect("TODO: Zaino's API should have caught this error for us");
+                        let txid = TxId::from_bytes(
+                            ReverseHex::decode(&txid_str)
+                                .expect("TODO: Zaino's API should have caught this error for us"),
+                        );
 
                         let tx = match chain.get_raw_transaction(txid_str, Some(1)).await? {
                             // TODO: Zaino should have a Rust API for fetching tx details,