ERC20PausableUpgradeable.sol 1.3 KB

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  1. // SPDX-License-Identifier: MIT
  2. // OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/ERC20Pausable.sol)
  3. pragma solidity ^0.8.0;
  4. import "../ERC20Upgradeable.sol";
  5. import "../../../security/PausableUpgradeable.sol";
  6. import "../../../proxy/utils/Initializable.sol";
  7. /**
  8. * @dev ERC20 token with pausable token transfers, minting and burning.
  9. *
  10. * Useful for scenarios such as preventing trades until the end of an evaluation
  11. * period, or having an emergency switch for freezing all token transfers in the
  12. * event of a large bug.
  13. */
  14. abstract contract ERC20PausableUpgradeable is Initializable, ERC20Upgradeable, PausableUpgradeable {
  15. function __ERC20Pausable_init() internal onlyInitializing {
  16. __Context_init_unchained();
  17. __Pausable_init_unchained();
  18. __ERC20Pausable_init_unchained();
  19. }
  20. function __ERC20Pausable_init_unchained() internal onlyInitializing {
  21. }
  22. /**
  23. * @dev See {ERC20-_beforeTokenTransfer}.
  24. *
  25. * Requirements:
  26. *
  27. * - the contract must not be paused.
  28. */
  29. function _beforeTokenTransfer(
  30. address from,
  31. address to,
  32. uint256 amount
  33. ) internal virtual override {
  34. super._beforeTokenTransfer(from, to, amount);
  35. require(!paused(), "ERC20Pausable: token transfer while paused");
  36. }
  37. uint256[50] private __gap;
  38. }