91 lines
2.1 KiB
Solidity
91 lines
2.1 KiB
Solidity
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// SPDX-License-Identifier: MIT
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pragma solidity ^0.6.0;
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import "../GSN/Context.sol";
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/**
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* @dev Contract module which allows children to implement an emergency stop
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* mechanism that can be triggered by an authorized account.
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*
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* This module is used through inheritance. It will make available the
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* modifiers `whenNotPaused` and `whenPaused`, which can be applied to
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* the functions of your contract. Note that they will not be pausable by
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* simply including this module, only once the modifiers are put in place.
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*/
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contract Pausable is Context {
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/**
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* @dev Emitted when the pause is triggered by `account`.
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*/
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event Paused(address account);
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/**
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* @dev Emitted when the pause is lifted by `account`.
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*/
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event Unpaused(address account);
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bool private _paused;
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/**
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* @dev Initializes the contract in unpaused state.
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*/
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constructor () internal {
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_paused = false;
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}
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/**
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* @dev Returns true if the contract is paused, and false otherwise.
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*/
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function paused() public view returns (bool) {
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return _paused;
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}
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/**
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* @dev Modifier to make a function callable only when the contract is not paused.
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*
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* Requirements:
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*
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* - The contract must not be paused.
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*/
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modifier whenNotPaused() {
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require(!_paused, "Pausable: paused");
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_;
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}
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/**
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* @dev Modifier to make a function callable only when the contract is paused.
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*
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* Requirements:
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*
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* - The contract must be paused.
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*/
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modifier whenPaused() {
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require(_paused, "Pausable: not paused");
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_;
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}
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/**
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* @dev Triggers stopped state.
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*
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* Requirements:
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*
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* - The contract must not be paused.
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*/
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function _pause() internal virtual whenNotPaused {
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_paused = true;
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emit Paused(_msgSender());
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}
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/**
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* @dev Returns to normal state.
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*
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* Requirements:
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*
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* - The contract must be paused.
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*/
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function _unpause() internal virtual whenPaused {
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_paused = false;
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emit Unpaused(_msgSender());
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}
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}
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