Merge pull request #23 from axieinfinity/merge/release/v0.1.0-feature…

…/math

chore(`math`): merge from `release/v0.1.0`

src/LibErrorHandler.sol

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.19;
+
+library LibErrorHandler {
+  /// @dev Reserves error definition to upload to signature database.
+  error ExternalCallFailed(bytes4 msgSig, bytes4 callSig);
+
+  /// @notice handle low level call revert if call failed,
+  /// If extcall return empty bytes, reverts with custom error.
+  /// @param status Status of external call
+  /// @param callSig function signature of the calldata
+  /// @param returnOrRevertData bytes result from external call
+  function handleRevert(bool status, bytes4 callSig, bytes memory returnOrRevertData) internal pure {
+    // Get the function signature of current context
+    bytes4 msgSig = msg.sig;
+    assembly ("memory-safe") {
+      if iszero(status) {
+        // Load the length of bytes array
+        let revertLength := mload(returnOrRevertData)
+        // Check if length != 0 => revert following reason from external call
+        if iszero(iszero(revertLength)) {
+          // Start of revert data bytes. The 0x20 offset is always the same.
+          revert(add(returnOrRevertData, 0x20), revertLength)
+        }
+
+        // Load free memory pointer
+        let ptr := mload(0x40)
+        // Store 4 bytes the function selector of ExternalCallFailed(msg.sig, callSig)
+        // Equivalent to revert ExternalCallFailed(bytes4,bytes4)
+        mstore(ptr, 0x49bf4104)
+        // Store 4 bytes of msgSig parameter in the next slot
+        mstore(add(ptr, 0x20), msgSig)
+        // Store 4 bytes of callSig parameter in the next slot
+        mstore(add(ptr, 0x40), callSig)
+        // Revert 68 bytes of error starting from 0x1c
+        revert(add(ptr, 0x1c), 0x44)
+      }
+    }
+  }
+}

src/transfers/LibNativeTransfer.sol

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import { LibErrorHandler } from "../LibErrorHandler.sol";
+
+/**
+ * @title NativeTransferHelper
+ */
+library LibNativeTransfer {
+  using LibErrorHandler for bool;
+
+  /**
+   * @dev Transfers Native Coin and wraps result for the method caller to a recipient.
+   */
+  function transfer(address to, uint256 value, uint256 gasAmount) internal {
+    (bool success, bytes memory returnOrRevertData) = trySendValue(to, value, gasAmount);
+    success.handleRevert(bytes4(0x0), returnOrRevertData);
+  }
+
+  /**
+   * @dev Unsafe send `amount` Native to the address `to`. If the sender's balance is insufficient,
+   * the call does not revert.
+   *
+   * Note:
+   * - Does not assert whether the balance of sender is sufficient.
+   * - Does not assert whether the recipient accepts NATIVE.
+   * - Consider using `ReentrancyGuard` before calling this function.
+   *
+   */
+  function trySendValue(address to, uint256 value, uint256 gasAmount)
+    internal
+    returns (bool success, bytes memory returnOrRevertData)
+  {
+    (success, returnOrRevertData) = to.call{ value: value, gas: gasAmount }("");
+  }
+}

test/transfers/LibNativeTransfer.t.sol

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.23;
+
+import { Test } from "forge-std/Test.sol";
+import { LibNativeTransfer } from "src/transfers/LibNativeTransfer.sol";
+
+contract LibNativeTransferTest is Test {
+  function testFork_RevertWhen_TransferNativeToContractWithoutFallback_safeTransfer(
+    address any,
+    uint256 amount,
+    uint256 gas
+  ) external {
+    vm.deal(any, amount);
+    vm.expectRevert();
+    vm.prank(any);
+    LibNativeTransfer.transfer(address(this), amount, gas);
+  }
+
+  function testConcrete_TransferNative(uint256 gas) external {
+    LibNativeTransfer.transfer(address(0xBEEF), 1e18, gas);
+    assertEq(address(0xBEEF).balance, 1e18);
+  }
+
+  function testFork_TransferNativeToRecipient(address recipient, uint256 amount, uint256 gas) external {
+    // Transferring to msg.sender can fail because it's possible to overflow their ETH balance as it begins non-zero.
+    if (recipient.code.length > 0 || uint256(uint160(recipient)) <= 18 || recipient == msg.sender) return;
+
+    amount = bound(amount, 0, address(this).balance);
+    LibNativeTransfer.transfer(recipient, amount, gas);
+
+    assertEq(recipient.balance, amount);
+  }
+}