no-std support for monero-serai (#311)

* Move monero-serai from std to std-shims, where possible

* no-std fixes

* Make the HttpRpc its own feature, thiserror only on std

* Drop monero-rs's epee for a homegrown one

We only need it for a single function. While I tried jeffro's, it didn't work
out of the box, had three unimplemented!s, and is no where near viable for
no_std.

Fixes #182, though should be further tested.

* no-std monero-serai

* Allow base58-monero via git

* cargo fmt

coins/monero/src/wallet/address.rs

@@ -1,7 +1,5 @@
 use core::{marker::PhantomData, fmt::Debug};
-use std::string::ToString;
-
-use thiserror::Error;
+use std_shims::string::{String, ToString};
 
 use zeroize::Zeroize;
 
@@ -114,19 +112,20 @@ impl<B: AddressBytes> Zeroize for AddressMeta<B> {
 }
 
 /// Error when decoding an address.
-#[derive(Clone, Copy, PartialEq, Eq, Debug, Error)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[cfg_attr(feature = "std", derive(thiserror::Error))]
 pub enum AddressError {
-  #[error("invalid address byte")]
+  #[cfg_attr(feature = "std", error("invalid address byte"))]
   InvalidByte,
-  #[error("invalid address encoding")]
+  #[cfg_attr(feature = "std", error("invalid address encoding"))]
   InvalidEncoding,
-  #[error("invalid length")]
+  #[cfg_attr(feature = "std", error("invalid length"))]
   InvalidLength,
-  #[error("invalid key")]
+  #[cfg_attr(feature = "std", error("invalid key"))]
   InvalidKey,
-  #[error("unknown features")]
+  #[cfg_attr(feature = "std", error("unknown features"))]
   UnknownFeatures,
-  #[error("different network than expected")]
+  #[cfg_attr(feature = "std", error("different network than expected"))]
   DifferentNetwork,
 }
 

coins/monero/src/wallet/decoys.rs

@@ -1,11 +1,16 @@
-use std_shims::{sync::OnceLock, collections::HashSet};
+use std_shims::{sync::OnceLock, vec::Vec, collections::HashSet};
 
+#[cfg(not(feature = "std"))]
+use std_shims::sync::Mutex;
+#[cfg(feature = "std")]
 use futures::lock::Mutex;
 
+use zeroize::{Zeroize, ZeroizeOnDrop};
+
 use rand_core::{RngCore, CryptoRng};
 use rand_distr::{Distribution, Gamma};
-
-use zeroize::{Zeroize, ZeroizeOnDrop};
+#[cfg(not(feature = "std"))]
+use rand_distr::num_traits::Float;
 
 use curve25519_dalek::edwards::EdwardsPoint;
 
@@ -143,6 +148,9 @@ impl Decoys {
     height: usize,
     inputs: &[SpendableOutput],
   ) -> Result<Vec<Decoys>, RpcError> {
+    #[cfg(not(feature = "std"))]
+    let mut distribution = DISTRIBUTION().lock();
+    #[cfg(feature = "std")]
     let mut distribution = DISTRIBUTION().lock().await;
 
     let decoy_count = ring_len - 1;

coins/monero/src/wallet/extra.rs

@@ -1,5 +1,8 @@
 use core::ops::BitXor;
-use std::io::{self, Read, Write};
+use std_shims::{
+  vec::Vec,
+  io::{self, Read, Write},
+};
 
 use zeroize::Zeroize;
 

coins/monero/src/wallet/mod.rs

@@ -1,5 +1,5 @@
 use core::ops::Deref;
-use std::collections::{HashSet, HashMap};
+use std_shims::collections::{HashSet, HashMap};
 
 use zeroize::{Zeroize, ZeroizeOnDrop, Zeroizing};
 
@@ -28,15 +28,15 @@ pub(crate) mod decoys;
 pub(crate) use decoys::Decoys;
 
 mod send;
-pub use send::{
-  Fee, TransactionError, Change, SignableTransaction, SignableTransactionBuilder, Eventuality,
-};
+pub use send::{Fee, TransactionError, Change, SignableTransaction, Eventuality};
+#[cfg(feature = "std")]
+pub use send::SignableTransactionBuilder;
 #[cfg(feature = "multisig")]
 pub(crate) use send::InternalPayment;
 #[cfg(feature = "multisig")]
 pub use send::TransactionMachine;
 
-fn key_image_sort(x: &EdwardsPoint, y: &EdwardsPoint) -> std::cmp::Ordering {
+fn key_image_sort(x: &EdwardsPoint, y: &EdwardsPoint) -> core::cmp::Ordering {
   x.compress().to_bytes().cmp(&y.compress().to_bytes()).reverse()
 }
 

coins/monero/src/wallet/scan.rs

@@ -1,5 +1,8 @@
 use core::ops::Deref;
-use std::io::{self, Read, Write};
+use std_shims::{
+  vec::Vec,
+  io::{self, Read, Write},
+};
 
 use zeroize::{Zeroize, ZeroizeOnDrop};
 

coins/monero/src/wallet/seed/classic.rs

@@ -1,5 +1,10 @@
 use core::ops::Deref;
-use std_shims::{sync::OnceLock, collections::HashMap};
+use std_shims::{
+  sync::OnceLock,
+  vec::Vec,
+  string::{String, ToString},
+  collections::HashMap,
+};
 
 use zeroize::{Zeroize, Zeroizing};
 use rand_core::{RngCore, CryptoRng};

coins/monero/src/wallet/seed/mod.rs

@@ -1,25 +1,25 @@
 use core::fmt;
+use std_shims::string::String;
 
 use zeroize::{Zeroize, ZeroizeOnDrop, Zeroizing};
 use rand_core::{RngCore, CryptoRng};
 
-use thiserror::Error;
-
 pub(crate) mod classic;
 use classic::{CLASSIC_SEED_LENGTH, CLASSIC_SEED_LENGTH_WITH_CHECKSUM, ClassicSeed};
 
 /// Error when decoding a seed.
-#[derive(Clone, Copy, PartialEq, Eq, Debug, Error)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[cfg_attr(feature = "std", derive(thiserror::Error))]
 pub enum SeedError {
-  #[error("invalid number of words in seed")]
+  #[cfg_attr(feature = "std", error("invalid number of words in seed"))]
   InvalidSeedLength,
-  #[error("unknown language")]
+  #[cfg_attr(feature = "std", error("unknown language"))]
   UnknownLanguage,
-  #[error("invalid checksum")]
+  #[cfg_attr(feature = "std", error("invalid checksum"))]
   InvalidChecksum,
-  #[error("english old seeds don't support checksums")]
+  #[cfg_attr(feature = "std", error("english old seeds don't support checksums"))]
   EnglishOldWithChecksum,
-  #[error("invalid seed")]
+  #[cfg_attr(feature = "std", error("invalid seed"))]
   InvalidSeed,
 }
 

coins/monero/src/wallet/send/mod.rs

@@ -1,7 +1,9 @@
 use core::{ops::Deref, fmt};
-use std::io;
-
-use thiserror::Error;
+use std_shims::{
+  vec::Vec,
+  io,
+  string::{String, ToString},
+};
 
 use rand_core::{RngCore, CryptoRng, SeedableRng};
 use rand_chacha::ChaCha20Rng;
@@ -42,7 +44,9 @@ use crate::{
   },
 };
 
+#[cfg(feature = "std")]
 mod builder;
+#[cfg(feature = "std")]
 pub use builder::SignableTransactionBuilder;
 
 #[cfg(feature = "multisig")]
@@ -116,34 +120,35 @@ impl SendOutput {
   }
 }
 
-#[derive(Clone, PartialEq, Eq, Debug, Error)]
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[cfg_attr(feature = "std", derive(thiserror::Error))]
 pub enum TransactionError {
-  #[error("multiple addresses with payment IDs")]
+  #[cfg_attr(feature = "std", error("multiple addresses with payment IDs"))]
   MultiplePaymentIds,
-  #[error("no inputs")]
+  #[cfg_attr(feature = "std", error("no inputs"))]
   NoInputs,
-  #[error("no outputs")]
+  #[cfg_attr(feature = "std", error("no outputs"))]
   NoOutputs,
-  #[error("only one output and no change address")]
+  #[cfg_attr(feature = "std", error("only one output and no change address"))]
   NoChange,
-  #[error("too many outputs")]
+  #[cfg_attr(feature = "std", error("too many outputs"))]
   TooManyOutputs,
-  #[error("too much data")]
+  #[cfg_attr(feature = "std", error("too much data"))]
   TooMuchData,
-  #[error("too many inputs/too much arbitrary data")]
+  #[cfg_attr(feature = "std", error("too many inputs/too much arbitrary data"))]
   TooLargeTransaction,
-  #[error("not enough funds (in {0}, out {1})")]
+  #[cfg_attr(feature = "std", error("not enough funds (in {0}, out {1})"))]
   NotEnoughFunds(u64, u64),
-  #[error("wrong spend private key")]
+  #[cfg_attr(feature = "std", error("wrong spend private key"))]
   WrongPrivateKey,
-  #[error("rpc error ({0})")]
+  #[cfg_attr(feature = "std", error("rpc error ({0})"))]
   RpcError(RpcError),
-  #[error("clsag error ({0})")]
+  #[cfg_attr(feature = "std", error("clsag error ({0})"))]
   ClsagError(ClsagError),
-  #[error("invalid transaction ({0})")]
+  #[cfg_attr(feature = "std", error("invalid transaction ({0})"))]
   InvalidTransaction(RpcError),
   #[cfg(feature = "multisig")]
-  #[error("frost error {0}")]
+  #[cfg_attr(feature = "std", error("frost error {0}"))]
   FrostError(FrostError),
 }
 

coins/monero/src/wallet/send/multisig.rs

@@ -1,8 +1,9 @@
-use std::{
+use std_shims::{
+  vec::Vec,
   io::{self, Read},
-  sync::{Arc, RwLock},
   collections::HashMap,
 };
+use std::sync::{Arc, RwLock};
 
 use zeroize::Zeroizing;