80 lines
2.7 KiB
Solidity
80 lines
2.7 KiB
Solidity
// SPDX-License-Identifier: MIT
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pragma solidity ^0.6.12;
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/**
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* @dev Interface of the ERC20 standard as defined in the EIP.
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*/
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interface IERC20 {
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/**
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* @dev Returns the amount of tokens in existence.
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*/
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function totalSupply() external view returns (uint256);
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function decimals() external view returns (uint8);
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/**
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* @dev Returns the amount of tokens owned by `account`.
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*/
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function balanceOf(address account) external view returns (uint256);
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/**
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* @dev Moves `amount` tokens from the caller's account to `recipient`.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* Emits a {Transfer} event.
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*/
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function transfer(address recipient, uint256 amount) external returns (bool);
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/**
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* @dev Returns the remaining number of tokens that `spender` will be
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* allowed to spend on behalf of `owner` through {transferFrom}. This is
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* zero by default.
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*
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* This value changes when {approve} or {transferFrom} are called.
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*/
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function allowance(address owner, address spender) external view returns (uint256);
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/**
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* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* IMPORTANT: Beware that changing an allowance with this method brings the risk
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* that someone may use both the old and the new allowance by unfortunate
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* transaction ordering. One possible solution to mitigate this race
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* condition is to first reduce the spender's allowance to 0 and set the
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* desired value afterwards:
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* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
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*
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* Emits an {Approval} event.
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*/
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function approve(address spender, uint256 amount) external returns (bool);
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/**
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* @dev Moves `amount` tokens from `sender` to `recipient` using the
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* allowance mechanism. `amount` is then deducted from the caller's
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* allowance.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* Emits a {Transfer} event.
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*/
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function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
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/**
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* @dev Emitted when `value` tokens are moved from one account (`from`) to
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* another (`to`).
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*
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* Note that `value` may be zero.
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*/
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event Transfer(address indexed from, address indexed to, uint256 value);
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/**
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* @dev Emitted when the allowance of a `spender` for an `owner` is set by
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* a call to {approve}. `value` is the new allowance.
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*/
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event Approval(address indexed owner, address indexed spender, uint256 value);
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}
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