Mumbai Testnet

Contract Diff Checker

Contract Name:
UUPSProxy

Contract Source Code:

// SPDX-License-Identifier: AGPLv3
pragma solidity 0.7.6;

import { UUPSUtils } from "./UUPSUtils.sol";
import { Proxy } from "@openzeppelin/contracts/proxy/Proxy.sol";


/**
 * @dev UUPS (Universal Upgradeable Proxy Standard) Proxy
 *
 * NOTE:
 * - Compliant with [Universal Upgradeable Proxy Standard](https://eips.ethereum.org/EIPS/eip-1822)
 * - Compiiant with [Standard Proxy Storage Slots](https://eips.ethereum.org/EIPS/eip-1967)
 * - Implements delegation of calls to other contracts, with proper forwarding of
 *   return values and bubbling of failures.
 * - It defines a fallback function that delegates all calls to the implementation.
 */
contract UUPSProxy is Proxy {

    /**
     * @dev Proxy initialization function.
     *      This should only be called once and it is permission-less.
     * @param initialAddress Initial logic contract code address to be used.
     */
    function initializeProxy(address initialAddress) external {
        require(initialAddress != address(0), "UUPSProxy: zero address");
        require(UUPSUtils.implementation() == address(0), "UUPSProxy: already initialized");
        UUPSUtils.setImplementation(initialAddress);
    }

    /// @dev Proxy._implementation implementation
    function _implementation() internal virtual override view returns (address)
    {
        return UUPSUtils.implementation();
    }

}

// SPDX-License-Identifier: AGPLv3
pragma solidity 0.7.6;

/**
 * @title UUPS (Universal Upgradeable Proxy Standard) Shared Library
 */
library UUPSUtils {

    /**
     * @dev Implementation slot constant.
     * Using https://eips.ethereum.org/EIPS/eip-1967 standard
     * Storage slot 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc
     * (obtained as bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1)).
     */
    bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /// @dev Get implementation address.
    function implementation() internal view returns (address impl) {
        assembly { // solium-disable-line
            impl := sload(_IMPLEMENTATION_SLOT)
        }
    }

    /// @dev Set new implementation address.
    function setImplementation(address codeAddress) internal {
        assembly {
            // solium-disable-line
            sstore(
                _IMPLEMENTATION_SLOT,
                codeAddress
            )
        }
    }

}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
 * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
 * be specified by overriding the virtual {_implementation} function.
 *
 * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
 * different contract through the {_delegate} function.
 *
 * The success and return data of the delegated call will be returned back to the caller of the proxy.
 */
abstract contract Proxy {
    /**
     * @dev Delegates the current call to `implementation`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal virtual {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
            // delegatecall returns 0 on error.
            case 0 { revert(0, returndatasize()) }
            default { return(0, returndatasize()) }
        }
    }

    /**
     * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
     * and {_fallback} should delegate.
     */
    function _implementation() internal view virtual returns (address);

    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback () external payable virtual {
        _fallback();
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive () external payable virtual {
        _fallback();
    }

    /**
     * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
     * call, or as part of the Solidity `fallback` or `receive` functions.
     *
     * If overriden should call `super._beforeFallback()`.
     */
    function _beforeFallback() internal virtual {
    }
}

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