mirror of
https://github.com/Instadapp/aave-protocol-v2.git
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62 lines
2.5 KiB
Solidity
62 lines
2.5 KiB
Solidity
// SPDX-License-Identifier: agpl-3.0
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pragma solidity 0.6.8;
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/**
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* @dev Collection of functions related to the address type
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*/
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library Address {
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/**
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* @dev Returns true if `account` is a contract.
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*
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* [IMPORTANT]
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* ====
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* It is unsafe to assume that an address for which this function returns
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* false is an externally-owned account (EOA) and not a contract.
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*
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* Among others, `isContract` will return false for the following
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* types of addresses:
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*
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* - an externally-owned account
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* - a contract in construction
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* - an address where a contract will be created
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* - an address where a contract lived, but was destroyed
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* ====
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*/
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function isContract(address account) internal view returns (bool) {
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// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
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// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
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// for accounts without code, i.e. `keccak256('')`
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bytes32 codehash;
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bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
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// solhint-disable-next-line no-inline-assembly
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assembly {
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codehash := extcodehash(account)
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}
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return (codehash != accountHash && codehash != 0x0);
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}
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/**
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* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
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* `recipient`, forwarding all available gas and reverting on errors.
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*
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* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
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* of certain opcodes, possibly making contracts go over the 2300 gas limit
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* imposed by `transfer`, making them unable to receive funds via
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* `transfer`. {sendValue} removes this limitation.
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*
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* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
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*
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* IMPORTANT: because control is transferred to `recipient`, care must be
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* taken to not create reentrancy vulnerabilities. Consider using
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* {ReentrancyGuard} or the
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* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
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*/
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function sendValue(address payable recipient, uint256 amount) internal {
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require(address(this).balance >= amount, 'Address: insufficient balance');
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// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
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(bool success, ) = recipient.call{value: amount}('');
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require(success, 'Address: unable to send value, recipient may have reverted');
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}
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}
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