feat: SafeErc20 utility

Cargo.toml

@@ -17,6 +17,7 @@ members = [
   "examples/basic/token",
   "examples/basic/script",
   "examples/ecdsa",
+  "examples/safe-erc20",
   "benches",
 ]
 default-members = [
@@ -30,6 +31,7 @@ default-members = [
   "examples/erc721",
   "examples/erc721-consecutive",
   "examples/erc721-metadata",
+  "examples/safe-erc20",
   "examples/merkle-proofs",
   "examples/ownable",
   "examples/access-control",

contracts/src/token/erc20/mod.rs

@@ -14,6 +14,7 @@ use stylus_sdk::{
 };
 
 pub mod extensions;
+pub mod utils;
 
 sol! {
     /// Emitted when `value` tokens are moved from one account (`from`) to

contracts/src/token/erc20/utils/mod.rs

@@ -0,0 +1,4 @@
+//! Utilities for the ERC-20 standard.
+pub mod safe_erc20;
+
+pub use safe_erc20::SafeErc20;

contracts/src/token/erc20/utils/safe_erc20.rs

@@ -0,0 +1,131 @@
+//! Wrappers around ERC-20 operations that throw on failure.
+
+use alloy_primitives::{Address, U256};
+use alloy_sol_types::sol;
+use stylus_proc::{public, sol_interface, sol_storage, SolidityError};
+use stylus_sdk::{call::Call, storage::TopLevelStorage, types::AddressVM};
+
+use crate::token::erc20;
+
+sol! {
+    /// An operation with an ERC-20 token failed.
+    #[derive(Debug)]
+    #[allow(missing_docs)]
+    error SafeErc20FailedOperation(address token);
+
+     /// Indicates a failed `decreaseAllowance` request.
+    #[derive(Debug)]
+    #[allow(missing_docs)]
+    error SafeErc20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);
+}
+
+/// A SafeErc20 error
+#[derive(SolidityError, Debug)]
+pub enum Error {
+    /// Error type from [`Erc20`] contract [`erc20::Error`].
+    Erc20(erc20::Error),
+    /// An operation with an ERC-20 token failed.
+    SafeErc20FailedOperation(SafeErc20FailedOperation),
+    /// Indicates a failed `decreaseAllowance` request.
+    SafeErc20FailedDecreaseAllowance(SafeErc20FailedDecreaseAllowance),
+}
+
+sol_interface! {
+    /// Interface of the ERC-20 standard as defined in the ERC.
+    interface IERC20 {
+        /// Moves a `value` amount of tokens from the caller's account to `to`.
+        ///
+        /// Returns a boolean value indicating whether the operation succeeded.
+        ///
+        /// Emits a {Transfer} event.
+        function transfer(address to, uint256 amount) external returns (bool);
+
+        /// Moves a `value` amount of tokens from `from` to `to` using the
+        /// allowance mechanism. `value` is then deducted from the caller's
+        /// allowance.
+        ///
+        /// Returns a boolean value indicating whether the operation succeeded.
+        ///
+        /// Emits a {Transfer} event.
+        function transferFrom(address from, address to, uint256 amount) external returns (bool);
+    }
+}
+
+sol_storage! {
+    /// Wrappers around ERC-20 operations that throw on failure (when the token
+    /// contract returns false). Tokens that return no value (and instead revert or
+    /// throw on failure) are also supported, non-reverting calls are assumed to be
+    /// successful.
+    /// To use this library you can add a `using SafeERC20 for IERC20;` statement to
+    /// your contract, which allows you to call the safe operations as
+    /// `token.safeTransfer(...)`, etc.
+    pub struct SafeErc20 {}
+}
+
+/// NOTE: Implementation of [`TopLevelStorage`] to be able use `&mut self` when
+/// calling other contracts and not `&mut (impl TopLevelStorage +
+/// BorrowMut<Self>)`. Should be fixed in the future by the Stylus team.
+unsafe impl TopLevelStorage for SafeErc20 {}
+
+#[public]
+impl SafeErc20 {
+    /// Transfer `value` amount of `token` from the calling contract to `to`. If
+    /// `token` returns no value, non-reverting calls are assumed to be
+    /// successful.
+    pub fn safe_transfer(
+        &mut self,
+        token: Address,
+        to: Address,
+        value: U256,
+    ) -> Result<(), Error> {
+        let erc20 = IERC20::new(token);
+        let call = Call::new_in(self);
+
+        match erc20.transfer(call, to, value) {
+            Ok(data) => {
+                if data && !Address::has_code(&token) {
+                    return Err(Error::SafeErc20FailedOperation(
+                        SafeErc20FailedOperation { token },
+                    ));
+                }
+            }
+            Err(_) => {
+                return Err(Error::SafeErc20FailedOperation(
+                    SafeErc20FailedOperation { token },
+                ))
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
+    /// calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
+    pub fn safe_transfer_from(
+        &mut self,
+        token: Address,
+        from: Address,
+        to: Address,
+        value: U256,
+    ) -> Result<(), Error> {
+        let erc20 = IERC20::new(token);
+        let call = Call::new_in(self);
+
+        match erc20.transfer_from(call, from, to, value) {
+            Ok(data) => {
+                if data && !Address::has_code(&token) {
+                    return Err(Error::SafeErc20FailedOperation(
+                        SafeErc20FailedOperation { token },
+                    ));
+                }
+            }
+            Err(_) => {
+                return Err(Error::SafeErc20FailedOperation(
+                    SafeErc20FailedOperation { token },
+                ))
+            }
+        }
+
+        Ok(())
+    }
+}

examples/safe-erc20/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "safe-erc20-example"
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+publish = false
+version = "0.0.0"
+
+[dependencies]
+openzeppelin-stylus = { path = "../../contracts" }
+alloy-primitives = { workspace = true, features = ["tiny-keccak"] }
+stylus-sdk.workspace = true
+stylus-proc.workspace = true
+mini-alloc.workspace = true
+
+[dev-dependencies]
+alloy.workspace = true
+eyre.workspace = true
+tokio.workspace = true
+e2e = { path = "../../lib/e2e" }
+
+[features]
+e2e = []
+
+[lib]
+crate-type = ["lib", "cdylib"]

examples/safe-erc20/src/constructor.sol

@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.21;
+
+contract SafeErc20Example {
+}

examples/safe-erc20/src/lib.rs

@@ -0,0 +1,29 @@
+#![cfg_attr(not(test), no_main, no_std)]
+extern crate alloc;
+
+use alloy_primitives::{Address, U256};
+use openzeppelin_stylus::token::erc20::utils::safe_erc20::{Error, SafeErc20};
+use stylus_sdk::prelude::{entrypoint, public, sol_storage};
+
+sol_storage! {
+    #[entrypoint]
+    struct SafeErc20Example {
+        #[borrow]
+        SafeErc20 safe_erc20;
+    }
+}
+
+#[public]
+#[inherit(SafeErc20)]
+impl SafeErc20Example {
+    // Add token minting feature.
+    pub fn safe_transfer(
+        &mut self,
+        token: Address,
+        to: Address,
+        value: U256,
+    ) -> Result<(), Error> {
+        self.safe_erc20.safe_transfer(token, to, value)?;
+        Ok(())
+    }
+}

examples/safe-erc20/tests/abi/mod.rs

@@ -0,0 +1,13 @@
+#![allow(dead_code)]
+use alloy::sol;
+
+sol!(
+    #[sol(rpc)]
+   contract SafeErc20 {
+        function safeTransfer(address token, address to, uint256 value) external;
+        function safeTransferFrom(address token, address from, address to, uint256 value) external;
+
+        error SafeErc20FailedOperation(address token);
+        error SafeErc20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);
+    }
+);

examples/safe-erc20/tests/mock/erc20.rs

@@ -0,0 +1,40 @@
+#![allow(dead_code)]
+#![cfg(feature = "e2e")]
+use alloy::{primitives::Address, sol};
+use e2e::Wallet;
+
+sol! {
+    #[allow(missing_docs)]
+    // Built with Remix IDE; solc v0.8.21+commit.d9974bed
+    #[sol(rpc, bytecode="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+    // SPDX-License-Identifier: MIT
+    contract ERC20Mock is ERC20 {
+        constructor() ERC20("MyToken", "MTK") {}
+
+        function approve(address spender, uint256 value) public override returns (bool) {
+            return super.approve(spender, value);
+        }
+
+        function balanceOf(address account) public override view returns (uint256) {
+            return super.balanceOf(account);
+        }
+
+        function mint(address account, uint256 value) public {
+            super._mint(account, value);
+        }
+
+        function transfer(address to, uint256 amount) public override returns (bool) {
+            return super.transfer(to, amount);
+        }
+
+        function transferFrom(address from, address to, uint256 value) public override returns (bool) {
+            return super.transferFrom(from, to, value);
+        }
+    }
+}
+
+pub async fn deploy(wallet: &Wallet) -> eyre::Result<Address> {
+    // Deploy the contract.
+    let contract = ERC20Mock::deploy(wallet).await?;
+    Ok(*contract.address())
+}

examples/safe-erc20/tests/mock/mod.rs

@@ -0,0 +1 @@
+pub mod erc20;