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https://github.com/nachomazzara/safeerc20
Library to standardize ERC20 methods calls
https://github.com/nachomazzara/safeerc20
Last synced: 4 days ago
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Library to standardize ERC20 methods calls
- Host: GitHub
- URL: https://github.com/nachomazzara/safeerc20
- Owner: nachomazzara
- Created: 2018-12-12T17:29:56.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2023-01-24T04:27:59.000Z (almost 2 years ago)
- Last Synced: 2023-04-10T18:52:06.038Z (over 1 year ago)
- Language: Solidity
- Size: 1.52 MB
- Stars: 6
- Watchers: 1
- Forks: 3
- Open Issues: 12
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# SafeERC20
Library that brings an abstract layer above the [ERC20 standard interface](https://github.com/OpenZeppelin/openzeppelin-eth/blob/master/contracts/token/ERC20/IERC20.sol) providing a way to call its methods safely by checking pre and post-conditions.
## Table of Content
1. [Interface](https://github.com/nachomazzara/SafeERC20/blob/master/README.md#interface)
2. [Usage](https://github.com/nachomazzara/SafeERC20/blob/master/README.md#usage)
## Interface
```solidity
/**
* @dev Transfer token for a specified address
* @param _token erc20 The address of the ERC20 contract
* @param _to address The address which you want to transfer to
* @param _value uint256 the _value of tokens to be transferred
* @return bool whether the transfer was successful or not
*/
function safeTransfer(IERC20 _token, address _to, uint256 _value) internal returns (bool);
/**
* @dev Transfer tokens from one address to another
* @param _token erc20 The address of the ERC20 contract
* @param _from address The address which you want to send tokens from
* @param _to address The address which you want to transfer to
* @param _value uint256 the _value of tokens to be transferred
* @return bool whether the transfer was successful or not
*/
function safeTransferFrom(
IERC20 _token,
address _from,
address _to,
uint256 _value
) internal returns (bool) ;
/**
* @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
*
* Beware that changing an allowance with this method brings the risk that someone may use both the old
* and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
* race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* @param _token erc20 The address of the ERC20 contract
* @param _spender The address which will spend the funds.
* @param _value The amount of tokens to be spent.
* @return bool whether the approve was successful or not
*/
function safeApprove(IERC20 _token, address _spender, uint256 _value) internal returns (bool)
```
## Usage
### _safeTransfer_
```solidity
pragma solidity ^0.4.24;
import "openzeppelin-eth/contracts/token/ERC20/IERC20.sol";
import "SafeERC20.sol";
contract MyContract {
using SafeERC20 for IERC20;
function myMethod() {
...
require(token.safeTransfer(to, value), "Transfer failed");
...
}
function myMethod2() {
...
if (token.safeTransfer(to, value)) {
// Do something on success
}
...
}
}
```
### _safeTransferFrom_
```solidity
pragma solidity ^0.4.24;
import "openzeppelin-eth/contracts/token/ERC20/IERC20.sol";
import "SafeERC20.sol";
contract MyContract {
using SafeERC20 for IERC20;
function myMethod() {
...
require(token.safeTransferFrom(owner, to, value), "Transfer from failed");
...
}
function myMethod2() {
...
if (token.safeTransferFrom(owner, to, value)) {
// Do something on success
}
...
}
}
```
### _safeApprove_
```solidity
pragma solidity ^0.4.24;
import "openzeppelin-eth/contracts/token/ERC20/IERC20.sol";
import "SafeERC20.sol";
contract MyContract {
using SafeERC20 for IERC20;
function myMethod() {
...
require(token.safeApprove(to, value), "Approve failed");
...
}
function myMethod2() {
...
if (token.safeApprove(to, value)) {
// Do something on success
}
...
}
}
```
### _clearApprove_
```solidity
pragma solidity ^0.4.24;
import "openzeppelin-eth/contracts/token/ERC20/IERC20.sol";
import "SafeERC20.sol";
contract MyContract {
using SafeERC20 for IERC20;
function myMethod() {
...
require(token.clearApprove(to), "Clear approval failed");
...
}
function myMethod2() {
...
if (token.clearApprove(to)) {
// Do something on success
}
...
}
}
```