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| 1 | +// SPDX-License-Identifier: MIT |
| 2 | +pragma solidity ^0.8.19; |
| 3 | + |
| 4 | +library LibErrorHandler { |
| 5 | + /// @dev Reserves error definition to upload to signature database. |
| 6 | + error ExternalCallFailed(bytes4 msgSig, bytes4 callSig); |
| 7 | + |
| 8 | + /// @notice handle low level call revert if call failed, |
| 9 | + /// If external call return empty bytes, reverts with custom error. |
| 10 | + /// @param status Status of external call |
| 11 | + /// @param callSig function signature of the calldata |
| 12 | + /// @param returnOrRevertData bytes result from external call |
| 13 | + function handleRevert(bool status, bytes4 callSig, bytes memory returnOrRevertData) internal pure { |
| 14 | + // Get the function signature of current context |
| 15 | + bytes4 msgSig = msg.sig; |
| 16 | + assembly ("memory-safe") { |
| 17 | + if iszero(status) { |
| 18 | + // Load the length of bytes array |
| 19 | + let revertLength := mload(returnOrRevertData) |
| 20 | + // Check if length != 0 => revert following reason from external call |
| 21 | + if iszero(iszero(revertLength)) { |
| 22 | + // Start of revert data bytes. The 0x20 offset is always the same. |
| 23 | + revert(add(returnOrRevertData, 0x20), revertLength) |
| 24 | + } |
| 25 | + |
| 26 | + // Load free memory pointer |
| 27 | + let ptr := mload(0x40) |
| 28 | + // Store 4 bytes the function selector of ExternalCallFailed(msg.sig, callSig) |
| 29 | + // Equivalent to revert ExternalCallFailed(bytes4,bytes4) |
| 30 | + mstore(ptr, 0x49bf4104) |
| 31 | + // Store 4 bytes of msgSig parameter in the next slot |
| 32 | + mstore(add(ptr, 0x20), msgSig) |
| 33 | + // Store 4 bytes of callSig parameter in the next slot |
| 34 | + mstore(add(ptr, 0x40), callSig) |
| 35 | + // Revert 68 bytes of error starting from 0x1c |
| 36 | + revert(add(ptr, 0x1c), 0x44) |
| 37 | + } |
| 38 | + } |
| 39 | + } |
| 40 | +} |
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