Smash ERC20 into its own library

.github/workflows/tests.yml

@@ -55,6 +55,7 @@ jobs:
             -p serai-processor-ethereum-contracts \
             -p serai-processor-ethereum-primitives \
             -p serai-processor-ethereum-deployer \
+            -p serai-processor-ethereum-erc20 \
             -p ethereum-serai \
             -p serai-ethereum-processor \
             -p serai-monero-processor \

Cargo.lock

@@ -8737,6 +8737,19 @@ dependencies = [
  "serai-processor-ethereum-primitives",
 ]
 
+[[package]]
+name = "serai-processor-ethereum-erc20"
+version = "0.1.0"
+dependencies = [
+ "alloy-core",
+ "alloy-provider",
+ "alloy-rpc-types-eth",
+ "alloy-simple-request-transport",
+ "alloy-sol-macro",
+ "alloy-sol-types",
+ "alloy-transport",
+]
+
 [[package]]
 name = "serai-processor-ethereum-primitives"
 version = "0.1.0"

Cargo.toml

@@ -90,6 +90,7 @@ members = [
   "processor/ethereum/contracts",
   "processor/ethereum/primitives",
   "processor/ethereum/deployer",
+  "processor/ethereum/erc20",
   "processor/ethereum/ethereum-serai",
   "processor/ethereum",
   "processor/monero",

deny.toml

@@ -62,6 +62,7 @@ exceptions = [
   { allow = ["AGPL-3.0"], name = "serai-processor-ethereum-contracts" },
   { allow = ["AGPL-3.0"], name = "serai-processor-ethereum-primitives" },
   { allow = ["AGPL-3.0"], name = "serai-processor-ethereum-deployer" },
+  { allow = ["AGPL-3.0"], name = "serai-processor-ethereum-erc20" },
   { allow = ["AGPL-3.0"], name = "ethereum-serai" },
   { allow = ["AGPL-3.0"], name = "serai-ethereum-processor" },
   { allow = ["AGPL-3.0"], name = "serai-monero-processor" },

processor/ethereum/erc20/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "serai-processor-ethereum-erc20"
+version = "0.1.0"
+description = "A library for the Serai Processor to interact with ERC20s"
+license = "AGPL-3.0-only"
+repository = "https://github.com/serai-dex/serai/tree/develop/processor/ethereum/erc20"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+edition = "2021"
+publish = false
+rust-version = "1.79"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[lints]
+workspace = true
+
+[dependencies]
+alloy-core = { version = "0.8", default-features = false }
+
+alloy-sol-types = { version = "0.8", default-features = false }
+alloy-sol-macro = { version = "0.8", default-features = false }
+
+alloy-rpc-types-eth = { version = "0.3", default-features = false }
+alloy-transport = { version = "0.3", default-features = false }
+alloy-simple-request-transport = { path = "../../../networks/ethereum/alloy-simple-request-transport", default-features = false }
+alloy-provider = { version = "0.3", default-features = false }

processor/ethereum/erc20/LICENSE

@@ -0,0 +1,15 @@
+AGPL-3.0-only license
+
+Copyright (c) 2022-2024 Luke Parker
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License Version 3 as
+published by the Free Software Foundation.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.

processor/ethereum/erc20/README.md

@@ -0,0 +1,3 @@
+# ERC20
+
+A library for the Serai Processor to interact with ERC20s.

processor/ethereum/erc20/src/lib.rs

@@ -1,3 +1,7 @@
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![doc = include_str!("../README.md")]
+#![deny(missing_docs)]
+
 use std::{sync::Arc, collections::HashSet};
 
 use alloy_core::primitives::{Address, B256, U256};
@@ -5,18 +9,31 @@ use alloy_core::primitives::{Address, B256, U256};
 use alloy_sol_types::{SolInterface, SolEvent};
 
 use alloy_rpc_types_eth::Filter;
+use alloy_transport::{TransportErrorKind, RpcError};
 use alloy_simple_request_transport::SimpleRequest;
 use alloy_provider::{Provider, RootProvider};
 
-use crate::Error;
-pub use crate::abi::erc20 as abi;
-use abi::{IERC20Calls, Transfer, transferCall, transferFromCall};
+#[rustfmt::skip]
+#[expect(warnings)]
+#[expect(needless_pass_by_value)]
+#[expect(clippy::all)]
+#[expect(clippy::ignored_unit_patterns)]
+#[expect(clippy::redundant_closure_for_method_calls)]
+mod abi {
+  alloy_sol_macro::sol!("contracts/IERC20.sol");
+}
+use abi::IERC20::{IERC20Calls, Transfer, transferCall, transferFromCall};
 
+/// A top-level ERC20 transfer
 #[derive(Clone, Debug)]
 pub struct TopLevelErc20Transfer {
+  /// The transaction ID which effected this transfer.
   pub id: [u8; 32],
+  /// The address which made the transfer.
   pub from: [u8; 20],
+  /// The amount transferred.
   pub amount: U256,
+  /// The data appended after the call itself.
   pub data: Vec<u8>,
 }
 
@@ -29,30 +46,43 @@ impl Erc20 {
     Self(provider, Address::from(&address))
   }
 
+  /// Fetch all top-level transfers to the specified ERC20.
   pub async fn top_level_transfers(
     &self,
     block: u64,
     to: [u8; 20],
-  ) -> Result<Vec<TopLevelErc20Transfer>, Error> {
+  ) -> Result<Vec<TopLevelErc20Transfer>, RpcError<TransportErrorKind>> {
     let filter = Filter::new().from_block(block).to_block(block).address(self.1);
     let filter = filter.event_signature(Transfer::SIGNATURE_HASH);
     let mut to_topic = [0; 32];
     to_topic[12 ..].copy_from_slice(&to);
     let filter = filter.topic2(B256::from(to_topic));
-    let logs = self.0.get_logs(&filter).await.map_err(|_| Error::ConnectionError)?;
+    let logs = self.0.get_logs(&filter).await?;
 
+    /*
+      A set of all transactions we've handled a transfer from. This handles the edge case where a
+      top-level transfer T somehow triggers another transfer T', with equivalent contents, within
+      the same transaction. We only want to report one transfer as only one is top-level.
+    */
     let mut handled = HashSet::new();
 
     let mut top_level_transfers = vec![];
     for log in logs {
       // Double check the address which emitted this log
       if log.address() != self.1 {
-        Err(Error::ConnectionError)?;
+        Err(TransportErrorKind::Custom(
+          "node returned logs for a different address than requested".to_string().into(),
+        ))?;
       }
 
-      let tx_id = log.transaction_hash.ok_or(Error::ConnectionError)?;
-      let tx =
-        self.0.get_transaction_by_hash(tx_id).await.ok().flatten().ok_or(Error::ConnectionError)?;
+      let tx_id = log.transaction_hash.ok_or_else(|| {
+        TransportErrorKind::Custom("log didn't specify its transaction hash".to_string().into())
+      })?;
+      let tx = self.0.get_transaction_by_hash(tx_id).await?.ok_or_else(|| {
+        TransportErrorKind::Custom(
+          "node didn't have the transaction which emitted a log it had".to_string().into(),
+        )
+      })?;
 
       // If this is a top-level call...
       if tx.to == Some(self.1) {
@@ -70,7 +100,13 @@ impl Erc20 {
             _ => continue,
           };
 
-          let log = log.log_decode::<Transfer>().map_err(|_| Error::ConnectionError)?.inner.data;
+          let log = log
+            .log_decode::<Transfer>()
+            .map_err(|e| {
+              TransportErrorKind::Custom(format!("failed to decode Transfer log: {e:?}").into())
+            })?
+            .inner
+            .data;
 
           // Ensure the top-level transfer is equivalent, and this presumably isn't a log for an
           // internal transfer