Initial commit

.eslintrc.js

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+module.exports = {
+    "extends": "airbnb-base",
+    "env": {
+        "mocha": true
+    },
+    "globals": {
+        "artifacts": true,
+        "contract": true,
+        "assert": true,
+        "web3": true
+    },
+    "rules": {
+        "max-len": 0
+    }
+};

.gitignore

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+.DS_Store
+node_modules
+build
+/dist
+types/truffle-contracts
+
+# local env files
+.env.local
+.env.*.local
+
+# Log files
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Editor directories and files
+.idea
+.vscode
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw*
+.node*

LICENSE

@@ -0,0 +1,165 @@
+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+  This version of the GNU Lesser General Public License incorporates
+the terms and conditions of version 3 of the GNU General Public
+License, supplemented by the additional permissions listed below.
+
+  0. Additional Definitions.
+
+  As used herein, "this License" refers to version 3 of the GNU Lesser
+General Public License, and the "GNU GPL" refers to version 3 of the GNU
+General Public License.
+
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+other than an Application or a Combined Work as defined below.
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+  You may convey a covered work under sections 3 and 4 of this License
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+  2. Conveying Modified Versions.
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+Library.

contracts/ContractProxy.sol

@@ -0,0 +1,96 @@
+pragma solidity ^0.4.24;
+
+import "./Ownable.sol";
+
+/**
+ * @title ContractProxy
+ * @dev The ContractProxy contract has an owner address and a contract address, and provides basic authorization control functions which simplifies the implementation of "proxies".
+ */
+contract ContractProxy is Ownable {
+  address public oldAddress;
+  address public contractAddress;
+
+  event ContractAddressUpdated(address previousAddress, address newAddress);
+
+  /**
+   * @dev The ContractProxy constructor sets the original `owner` and the initial `address` of the contract to the sender account.
+   */
+  constructor(address _contractAddress) public nonZeroAddress(_contractAddress) {
+    contractAddress = _contractAddress;
+  }
+
+  /**
+   * @dev Throws if coming address is zero
+   */
+  modifier nonZeroAddress(address addr) { require(addr != address(0)); _; }
+
+  /**
+   * @dev Allows the current owner to update the contractAddress
+   * @param _newAddress The address of the new contract
+   */
+  function UpdateContractAddress(address _newAddress) public onlyOwner nonZeroAddress(_newAddress) {
+    oldAddress = contractAddress;
+    contractAddress = _newAddress;
+    emit ContractAddressUpdated(oldAddress, _newAddress);
+  }
+
+  /**
+  * @dev Fallback function allowing to perform a delegatecall to the given implementation.
+  * This function will return whatever the implementation call returns
+  * https://github.com/poanetwork/poa-bridge-contracts/blob/master/contracts/upgradeability/Proxy.sol
+  */
+  function() payable public {
+    address _impl = contractAddress;
+    require(_impl != address(0));
+    assembly {
+      /*
+        0x40 is the "free memory slot", meaning a pointer to next slot of empty memory. mload(0x40) loads the data in the free memory slot, so `ptr` is a pointer to the next slot of empty memory. It's needed because we're going to write the return data of delegatecall to the free memory slot.
+      */
+      let ptr := mload(0x40)
+      /*
+        `calldatacopy` is copy calldatasize bytes from calldata
+        First argument is the destination to which data is copied(ptr)
+        Second argument specifies the start position of the copied data. Since calldata is sort of its own unique location in memory, 0 doesn't refer to 0 in memory or 0 in storage - it just refers to the zeroth byte of calldata. That's always going to be the zeroth byte of the function selector.
+        Third argument, calldatasize, specifies how much data will be copied. calldata is naturally calldatasize bytes long (same thing as msg.data.length)
+      */
+      calldatacopy(ptr, 0, calldatasize)
+      /*
+        delegatecall params explained:
+        gas: the amount of gas to provide for the call. `gas` is an Opcode that gives us the amount of gas still available to execution
+        _impl: address of the contract to delegate to
+        ptr: to pass copied data
+        calldatasize: loads the size of `bytes memory data`, same as msg.data.length
+        0, 0: These are for the `out` and `outsize` params. Because the output could be dynamic, these are set to 0, 0 so the output data will not be written to memory. The output data will be read using `returndatasize` and `returdatacopy` instead.
+        result: This will be 0 if the call fails and 1 if it succeeds
+      */
+      let result := delegatecall(gas, _impl, ptr, calldatasize, 0, 0)
+      /*
+      */
+      /*
+        ptr current points to the value stored at 0x40,
+        because we assigned it like ptr := mload(0x40).
+        Because we use 0x40 as a free memory pointer,
+        we want to make sure that the next time we want to allocate memory,
+        we aren't overwriting anything important.
+        So, by adding ptr and returndatasize,
+        we get a memory location beyond the end of the data we will be copying to ptr.
+        We place this in at 0x40, and any reads from 0x40 will now read from free memory
+      */
+      mstore(0x40, add(ptr, returndatasize))
+      /*
+        `returndatacopy` is an Opcode that copies the last return data to a slot. `ptr` is the slot it will copy to, 0 means copy from the beginning of the return data, and size is the amount of data to copy.
+        `returndatasize` is an Opcode that gives us the size of the last return data. In this case, that is the size of the data returned from delegatecall
+      */
+      returndatacopy(ptr, 0, returndatasize)
+
+      /*
+        if `result` is 0, revert.
+        if `result` is 1, return `size` amount of data from `ptr`. This is the data that was
+        copied to `ptr` from the delegatecall return data
+      */
+      switch result
+      case 0 { revert(ptr, returndatasize) }
+      default { return(ptr, returndatasize) }
+    }
+  }
+}

contracts/EIP20Standard.sol

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+pragma solidity ^0.4.24;
+
+interface EIP20Standard {
+  event Transfer(address indexed _from, address indexed _to, uint256 _value);
+  event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+
+  function name() external view returns (string);
+  function symbol() external view returns (string);
+  function decimals() external view returns (uint8);
+  function totalSupply() external view returns (uint256);
+
+  function balanceOf(address _owner) external view returns (uint256 balance);
+  function allowance(address _owner, address _spender) external view returns (uint256 remaining);
+
+  function transfer(address _to, uint256 _value) external returns (bool success);
+  function transferFrom(address _from, address _to, uint256 _value) external returns (bool success);
+  function approve(address _spender, uint256 _value) external returns (bool success);
+}