Merge pull request #1659 from zcash/zcash_transparent_no_std

Implement `no_std` support for `zcash_transparent`

zcash_transparent/Cargo.toml

@@ -18,6 +18,7 @@ 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.)

zcash_transparent/src/address.rs

@@ -1,12 +1,14 @@
 //! Support for legacy transparent addresses and scripts.
 
 use byteorder::{ReadBytesExt, WriteBytesExt};
-use zcash_address::TryFromRawAddress;
 
-use std::fmt;
-use std::io::{self, Read, Write};
-use std::ops::Shl;
+use alloc::string::String;
+use alloc::vec::Vec;
+use core::fmt;
+use core::ops::Shl;
+use core2::io::{self, Read, Write};
 
+use zcash_address::TryFromRawAddress;
 use zcash_encoding::Vector;
 
 /// Defined script opcodes.

zcash_transparent/src/builder.rs

@@ -1,7 +1,8 @@
 //! Types and functions for building transparent transaction components.
 
-use std::collections::BTreeMap;
-use std::fmt;
+use alloc::collections::BTreeMap;
+use alloc::vec::Vec;
+use core::fmt;
 
 use zcash_protocol::value::{BalanceError, ZatBalance as Amount, Zatoshis as NonNegativeAmount};
 
@@ -287,7 +288,7 @@ impl TxIn<Unauthorized> {
         TxIn {
             prevout,
             script_sig: (),
-            sequence: std::u32::MAX,
+            sequence: u32::MAX,
         }
     }
 }
@@ -362,7 +363,7 @@ impl Bundle<Unauthorized> {
             });
 
         #[cfg(not(feature = "transparent-inputs"))]
-        let script_sigs = std::iter::empty::<Result<Script, Error>>();
+        let script_sigs = core::iter::empty::<Result<Script, Error>>();
 
         Ok(Bundle {
             vin: self

zcash_transparent/src/bundle.rs

@@ -1,12 +1,15 @@
 //! Structs representing the components within Zcash transactions.
 
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
-use zcash_protocol::TxId;
 
-use std::fmt::Debug;
-use std::io::{self, Read, Write};
+use alloc::vec::Vec;
+use core::fmt::Debug;
+use core2::io::{self, Read, Write};
 
-use zcash_protocol::value::{BalanceError, ZatBalance as Amount, Zatoshis as NonNegativeAmount};
+use zcash_protocol::{
+    value::{BalanceError, ZatBalance as Amount, Zatoshis as NonNegativeAmount},
+    TxId,
+};
 
 use crate::{
     address::{Script, TransparentAddress},

zcash_transparent/src/keys.rs

@@ -1,5 +1,7 @@
 //! Transparent key components.
 
+use alloc::string::ToString;
+use alloc::vec::Vec;
 use bip32::{
     ChildNumber, ExtendedKey, ExtendedKeyAttrs, ExtendedPrivateKey, ExtendedPublicKey, Prefix,
 };
@@ -341,7 +343,7 @@ pub(crate) mod private {
 ///
 /// [BIP32]: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
 /// [BIP44]: https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki
-pub trait IncomingViewingKey: private::SealedChangeLevelKey + std::marker::Sized {
+pub trait IncomingViewingKey: private::SealedChangeLevelKey + core::marker::Sized {
     /// Derives a transparent address at the provided child index.
     #[allow(deprecated)]
     fn derive_address(

zcash_transparent/src/lib.rs

@@ -1,5 +1,7 @@
 //! # Zcash transparent protocol
 
+#![no_std]
+
 pub mod address;
 pub mod builder;
 pub mod bundle;
@@ -8,3 +10,6 @@ pub mod sighash;
 
 #[cfg(feature = "transparent-inputs")]
 pub mod keys;
+
+#[macro_use]
+extern crate alloc;

zcash_transparent/src/pczt.rs

@@ -1,6 +1,8 @@
 //! PCZT support for transparent Zcash.
 
-use std::collections::BTreeMap;
+use alloc::collections::BTreeMap;
+use alloc::string::String;
+use alloc::vec::Vec;
 
 use bip32::ChildNumber;
 use getset::Getters;

zcash_transparent/src/pczt/parse.rs

@@ -1,4 +1,6 @@
-use std::collections::BTreeMap;
+use alloc::collections::BTreeMap;
+use alloc::string::String;
+use alloc::vec::Vec;
 
 use bip32::ChildNumber;
 use zcash_protocol::{value::Zatoshis, TxId};

zcash_transparent/src/pczt/signer.rs

@@ -1,4 +1,5 @@
 use crate::sighash::SignableInput;
+use alloc::vec::Vec;
 
 impl super::Input {
     /// Signs the transparent spend with the given spend authorizing key.

zcash_transparent/src/pczt/tx_extractor.rs

@@ -1,3 +1,4 @@
+use alloc::vec::Vec;
 use zcash_protocol::value::Zatoshis;
 
 use crate::{
@@ -57,7 +58,7 @@ impl super::Bundle {
                 Ok(TxIn {
                     prevout,
                     script_sig: script_sig(input)?,
-                    sequence: input.sequence.unwrap_or(std::u32::MAX),
+                    sequence: input.sequence.unwrap_or(u32::MAX),
                 })
             })
             .collect::<Result<Vec<_>, E>>()?;

zcash_transparent/src/pczt/updater.rs

@@ -1,3 +1,5 @@
+use alloc::string::String;
+use alloc::vec::Vec;
 use ripemd::Ripemd160;
 use sha2::{Digest, Sha256};
 

zcash_transparent/src/sighash.rs

@@ -1,3 +1,4 @@
+use alloc::vec::Vec;
 use getset::Getters;
 use zcash_protocol::value::Zatoshis;