From 7bff034c59acf4be8fbf28a1ea7b204bdf2f4cdd Mon Sep 17 00:00:00 2001
From: Jack Grigg <jack@electriccoin.co>
Date: Mon, 16 Dec 2024 09:34:45 +0000
Subject: [PATCH] zcash_transparent: Fix its dependencies to work with no-std

---
 Cargo.lock                           |  1 -
 Cargo.toml                           | 16 ++++++++--------
 components/zcash_protocol/Cargo.toml |  3 ++-
 components/zip321/Cargo.toml         |  4 ++--
 zcash_primitives/Cargo.toml          |  2 +-
 zcash_transparent/Cargo.toml         | 12 +++++++++---
 zcash_transparent/src/address.rs     |  9 +++++----
 zcash_transparent/src/bundle.rs      | 17 ++++++++++-------
 zcash_transparent/src/lib.rs         |  4 ++++
 9 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index d4b3a49972..f61fb3faaa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6451,7 +6451,6 @@ dependencies = [
  "bip32",
  "blake2b_simd",
  "bs58",
- "byteorder",
  "core2",
  "document-features",
  "getset",
diff --git a/Cargo.toml b/Cargo.toml
index b2528ee169..065b35f650 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -34,7 +34,7 @@ categories = ["cryptography::cryptocurrencies"]
 [workspace.dependencies]
 # Intra-workspace dependencies
 equihash = { version = "0.2", path = "components/equihash" }
-zcash_address = { version = "0.6", path = "components/zcash_address" }
+zcash_address = { version = "0.6", path = "components/zcash_address", default-features = false }
 zcash_client_backend = { version = "0.15", path = "zcash_client_backend" }
 zcash_encoding = { version = "0.2.1", path = "components/zcash_encoding", default-features = false }
 zcash_keys = { version = "0.5", path = "zcash_keys" }
@@ -71,8 +71,8 @@ pasta_curves = "0.5"
 
 # - Transparent
 bip32 = { version = "0.5", default-features = false }
-ripemd = "0.1"
-secp256k1 = "0.27"
+ripemd = { version = "0.1", default-features = false }
+secp256k1 = { version = "0.27", default-features = false, features = ["alloc"] }
 transparent = { package = "zcash_transparent", version = "0.0", path = "zcash_transparent", default-features = false }
 
 # Boilerplate
@@ -86,8 +86,8 @@ rand_core = "0.6"
 rust_decimal = { version = "1.35", default-features = false, features = ["serde"] }
 
 # Digests
-blake2b_simd = "1"
-sha2 = "0.10"
+blake2b_simd = { version = "1", default-features = false }
+sha2 = { version = "0.10", default-features = false }
 
 # Documentation
 document-features = "0.2"
@@ -97,7 +97,7 @@ base64 = "0.22"
 bech32 = { version = "0.11", default-features = false, features = ["alloc"] }
 bs58 = { version = "0.5", default-features = false, features = ["alloc", "check"] }
 byteorder = "1"
-hex = "0.4"
+hex = { version = "0.4", default-features = false, features = ["alloc"] }
 percent-encoding = "2.1.0"
 postcard = { version = "1", features = ["alloc"] }
 serde = { version = "1", features = ["derive"] }
@@ -129,7 +129,7 @@ tonic-build = { version = "0.12", default-features = false }
 
 # Secret management
 secrecy = "0.8"
-subtle = "2.2.3"
+subtle = { version = "2.2.3", default-features = false }
 
 # SQLite databases
 # - Warning: One of the downstream consumers requires that SQLite be available through
@@ -167,7 +167,7 @@ trait-variant = "0.1"
 # ZIP 32
 aes = "0.8"
 fpe = "0.6"
-zip32 = "0.1.1"
+zip32 = { version = "0.1.1", default-features = false }
 
 [profile.release]
 lto = true
diff --git a/components/zcash_protocol/Cargo.toml b/components/zcash_protocol/Cargo.toml
index ac79e5df1f..093e024d05 100644
--- a/components/zcash_protocol/Cargo.toml
+++ b/components/zcash_protocol/Cargo.toml
@@ -42,7 +42,8 @@ proptest.workspace = true
 
 [features]
 default = ["std"]
-std = ["document-features", "dep:memuse"]
+std = ["dep:document-features", "dep:memuse"]
+
 ## Exposes APIs that are useful for testing, such as `proptest` strategies.
 test-dependencies = [
     "dep:incrementalmerkletree",
diff --git a/components/zip321/Cargo.toml b/components/zip321/Cargo.toml
index be67284a39..a5b2f076ec 100644
--- a/components/zip321/Cargo.toml
+++ b/components/zip321/Cargo.toml
@@ -15,7 +15,7 @@ categories.workspace = true
 
 [dependencies]
 zcash_address.workspace = true
-zcash_protocol.workspace = true
+zcash_protocol = { workspace = true, features = ["std"] }
 
 # - Parsing and Encoding
 nom = "7"
@@ -27,7 +27,7 @@ proptest = { workspace = true, optional = true }
 
 [dev-dependencies]
 zcash_address = { workspace = true, features = ["test-dependencies"] }
-zcash_protocol = { workspace = true, features = ["test-dependencies"] }
+zcash_protocol = { workspace = true, features = ["std", "test-dependencies"] }
 proptest.workspace = true
 
 [features]
diff --git a/zcash_primitives/Cargo.toml b/zcash_primitives/Cargo.toml
index da79c8d4e1..c9b9b49e66 100644
--- a/zcash_primitives/Cargo.toml
+++ b/zcash_primitives/Cargo.toml
@@ -21,7 +21,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 [dependencies]
 equihash.workspace = true
 zcash_address.workspace = true
-zcash_encoding.workspace = true
+zcash_encoding = { workspace = true, features = ["std"] }
 zcash_protocol.workspace = true
 zip32.workspace = true
 
diff --git a/zcash_transparent/Cargo.toml b/zcash_transparent/Cargo.toml
index dad6617875..30fa5933c5 100644
--- a/zcash_transparent/Cargo.toml
+++ b/zcash_transparent/Cargo.toml
@@ -18,7 +18,6 @@ zcash_address.workspace = true
 zcash_encoding.workspace = true
 zcash_protocol.workspace = true
 zip32.workspace = true
-core2.workspace = true
 
 # Dependencies exposed in a public API:
 # (Breaking upgrades to these require a breaking upgrade to this crate.)
@@ -26,6 +25,9 @@ core2.workspace = true
 blake2b_simd.workspace = true
 sha2.workspace = true
 
+# - Encodings
+core2.workspace = true
+
 # - Secret management
 subtle.workspace = true
 
@@ -47,17 +49,21 @@ secp256k1 = { workspace = true, optional = true }
 getset.workspace = true
 
 # - Documentation
-document-features.workspace = true
+document-features = { workspace = true, optional = true }
 
 # - Encodings
 bs58.workspace = true
-byteorder.workspace = true
 hex.workspace = true
 
 # - Transparent protocol
 ripemd.workspace = true
 
 [features]
+default = ["std"]
+std = [
+    "dep:document-features",
+]
+
 ## Enables spending transparent notes with the transaction builder.
 transparent-inputs = ["bip32/secp256k1-ffi", "dep:secp256k1"]
 
diff --git a/zcash_transparent/src/address.rs b/zcash_transparent/src/address.rs
index 16fb5bfcfd..464652d047 100644
--- a/zcash_transparent/src/address.rs
+++ b/zcash_transparent/src/address.rs
@@ -1,7 +1,5 @@
 //! Support for legacy transparent addresses and scripts.
 
-use byteorder::{ReadBytesExt, WriteBytesExt};
-
 use alloc::string::String;
 use alloc::vec::Vec;
 use core::fmt;
@@ -314,12 +312,15 @@ impl fmt::Debug for Script {
 
 impl Script {
     pub fn read<R: Read>(mut reader: R) -> io::Result<Self> {
-        let script = Vector::read(&mut reader, |r| r.read_u8())?;
+        let script = Vector::read(&mut reader, |r| {
+            let mut bytes = [0; 1];
+            r.read_exact(&mut bytes).map(|_| bytes[0])
+        })?;
         Ok(Script(script))
     }
 
     pub fn write<W: Write>(&self, mut writer: W) -> io::Result<()> {
-        Vector::write(&mut writer, &self.0, |w, e| w.write_u8(*e))
+        Vector::write(&mut writer, &self.0, |w, e| w.write_all(&[*e]))
     }
 
     /// Returns the length of this script as encoded (including the initial CompactSize).
diff --git a/zcash_transparent/src/bundle.rs b/zcash_transparent/src/bundle.rs
index 6366d3b7ec..e6235b9bc1 100644
--- a/zcash_transparent/src/bundle.rs
+++ b/zcash_transparent/src/bundle.rs
@@ -1,7 +1,5 @@
 //! Structs representing the components within Zcash transactions.
 
-use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
-
 use alloc::vec::Vec;
 use core::fmt::Debug;
 use core2::io::{self, Read, Write};
@@ -160,13 +158,14 @@ impl OutPoint {
     pub fn read<R: Read>(mut reader: R) -> io::Result<Self> {
         let mut hash = [0u8; 32];
         reader.read_exact(&mut hash)?;
-        let n = reader.read_u32::<LittleEndian>()?;
-        Ok(OutPoint::new(hash, n))
+        let mut n = [0; 4];
+        reader.read_exact(&mut n)?;
+        Ok(OutPoint::new(hash, u32::from_le_bytes(n)))
     }
 
     pub fn write<W: Write>(&self, mut writer: W) -> io::Result<()> {
         writer.write_all(self.hash.as_ref())?;
-        writer.write_u32::<LittleEndian>(self.n)
+        writer.write_all(&self.n.to_le_bytes())
     }
 
     /// Returns `true` if this `OutPoint` is "null" in the Bitcoin sense: it has txid set to
@@ -204,7 +203,11 @@ impl TxIn<Authorized> {
     pub fn read<R: Read>(mut reader: &mut R) -> io::Result<Self> {
         let prevout = OutPoint::read(&mut reader)?;
         let script_sig = Script::read(&mut reader)?;
-        let sequence = reader.read_u32::<LittleEndian>()?;
+        let sequence = {
+            let mut sequence = [0; 4];
+            reader.read_exact(&mut sequence)?;
+            u32::from_le_bytes(sequence)
+        };
 
         Ok(TxIn {
             prevout,
@@ -216,7 +219,7 @@ impl TxIn<Authorized> {
     pub fn write<W: Write>(&self, mut writer: W) -> io::Result<()> {
         self.prevout.write(&mut writer)?;
         self.script_sig.write(&mut writer)?;
-        writer.write_u32::<LittleEndian>(self.sequence)
+        writer.write_all(&self.sequence.to_le_bytes())
     }
 }
 
diff --git a/zcash_transparent/src/lib.rs b/zcash_transparent/src/lib.rs
index dff01212bb..96f6144408 100644
--- a/zcash_transparent/src/lib.rs
+++ b/zcash_transparent/src/lib.rs
@@ -1,4 +1,8 @@
 //! # Zcash transparent protocol
+//!
+#![cfg_attr(feature = "std", doc = "## Feature flags")]
+#![cfg_attr(feature = "std", doc = document_features::document_features!())]
+//!
 
 #![no_std]