EIP-1167 Clone Factory (#1162)

contracts/mocks/SimpleCloneFactory.sol

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+pragma solidity ^0.4.24;
+
+import "../utils/CloneFactory.sol";
+import "../examples/SimpleToken.sol";
+
+/**
+ * @title Simple Clone Contract Factory
+ * 
+ * @dev This code (intended to be called from an implementor factory contract)
+ * will allow you to install a master copy of the SimpleToken contract, then easily
+ * (cheaply) create clones with separate state. The deployed bytecode just
+ * delegates all calls to the master contract address.
+ *
+ * 1) Be sure that the master contract is pre-initialized.
+ * 2) Do not allow your master contract to be self-destructed as it will cause
+ *    all clones to stop working
+ */
+contract SimpleCloneFactory is CloneFactory {
+
+  address public originAddress;
+
+  constructor() public {
+    originAddress = new SimpleToken();
+  }
+
+  function createNew() public returns (bool) {
+    createClone(originAddress);
+    return true;
+  }
+}

contracts/utils/CloneFactory.sol

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+pragma solidity ^0.4.24;
+
+/*
+The MIT License (MIT)
+
+Copyright (c) 2018 Murray Software, LLC.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+/**
+ * @title EIP 1167: Minimal Proxy Contract
+ *
+ * @dev To simply and cheaply clone contract functionality in an immutable way,
+ * this standard specifies a minimal bytecode implementation that delegates
+ * all calls to a known, fixed address.
+ *
+ * https://eips.ethereum.org/EIPS/eip-1167
+ */
+contract CloneFactory {
+
+  event CloneCreated(address indexed originAddress, address clonedAddress);
+
+  function createClone(address target) internal returns (address result) {
+    // solium-disable-next-line
+    bytes memory clone = hex"3d602d80600a3d3981f3363d3d373d3d3d363d73bebebebebebebebebebebebebebebebebebebebe5af43d82803e903d91602b57fd5bf3";
+    bytes20 targetBytes = bytes20(target);
+    for (uint i = 0; i < 20; i++) {
+      clone[20 + i] = targetBytes[i];
+    }
+    // solium-disable-next-line security/no-inline-assembly
+    assembly {
+      let len := mload(clone)
+      let data := add(clone, 0x20)
+      result := create(0, data, len)
+    }
+    emit CloneCreated(target, result);
+  }
+}

test/CloneFactory.test.js

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+const SimpleToken = artifacts.require('SimpleToken');
+const SimpleCloneFactory = artifacts.require('SimpleCloneFactory');
+
+const BigNumber = web3.BigNumber;
+
+require('chai')
+  .use(require('chai-bignumber')(BigNumber))
+  .should();
+
+contract('CloneFactory', function ([_, owner]) {
+  let factory;
+
+  describe('factory initialized', function () {
+    beforeEach(async function () {
+      factory = await initFactory();
+    });
+
+    it('should create proxy contract with valid bytecode', async function () {
+      const proxy = await factory.createNew();
+      (await readContractCode(proxy.address)).should.be.equal(expectedBytcode());
+    });
+  });
+
+  const initFactory = async function () {
+    const _factory = await SimpleCloneFactory.new();
+    const _originAddress = await _factory.originAddress();
+    return {
+      createNew: async function () {
+        const tx = await _factory.createNew();
+        return SimpleToken.at(tx.logs[0].args.clonedAddress);
+      },
+      originAddress: function () {
+        return _originAddress;
+      },
+    };
+  };
+
+  const readContractCode = async function (contractAddress) {
+    return web3.eth.getCode(contractAddress);
+  };
+
+  const expectedBytcode = function () {
+    const originAddress = factory.originAddress();
+    return '0x363d3d373d3d3d363d73' + originAddress.substring(2) + '5af43d82803e903d91602b57fd5bf3';
+  };
+});