Feature/erc777 #1159 (#1684)

* IERC777 from specs, constants returned, up to defaultOperators. (#1159)

* IERC777 oprarator approvals (#1159)

* ERC777 oprarator approvals fixes and tests

* IERC777 send and receive with ERC820 (#1159)

* ERC777 Add burn functions and fix send functions (#1159)

* ERC777 Make expectEvent compatible with web3.js 1.0 (#1159)

* ERC777 Add ERC820 deploy script (#1159)

* ERC777 Complete implementation of ERC777 (#1159)

This implementation conforms to the current EIP

* ERC777 Update ERC820 Registry contract to final version (#1159)

* ERC777 Move contracts to 'drafts' folder (#1159)

* ERC777: Update to ERC1820 registry and linter error fix (#1159)

* ERC777: implement recent changes of EIP777 (#1159)

* ERC777 Fix formatting (#1159)

* ERC777 Update to solc 0.5.2 (#1159)

* ERC777 Fix travis CI errors (#1159)

* ERC777 Fix linter errors again... (#1159)

* ERC777 Fix unit test (#1159)

* ERC777 Fix unit test again (#1159)

* Remove extra newlines.

* Rename ERC777Base to ERC777.

* Remove 'Token' from contract names.

* Replace ops for operators.

* Move operator check out of _send.

* Remove ERC777Burnable.

* Remove ERC1820Client, now using the interface directly.

* Minor internal refactors in contracts.

* Delete extra test helpers.

* Simplified tests.

* Add basic 777 tests.

* Add granularity send test.

* Add first operator send tests.

* Add burn tests.

* Refactor send and burn tests.

* Improve send burn refactor.

* Greatly improve test module.

* Burn instead of send removed tokens.

* Add operator tests.

* Improve send tests under changing operators.

* Refactor and merge send and burn tests.

* Add missing and not-implemented tests.

* Make _burn private.

* Fix typo.

* Greatly improve tokensToSend tests.

* Refactor hook tests.

* Fix hook tests.

* Update openzeppelin-test-helpers and ERC1820 address.

* Fix natspec indentation.

* Make interface functions external.

* Remove redundant private revoke and authorize functions.

* Improved readability of if statement.

* Remove unnecessary asserts.

* Add non-one granularity test.

* Fix hook call order in _mint.

* Fix _mint not reverting on failure to implement tokensReceived.

* Remove special case in operatorFn when from is 0.

* Refactor ERC777SenderMock.

* Add tokensReceived tests.

* switch to updated ganache-cli-coverage fork

* Fix linter errors.

* Add mint tests.

* Fix linter errors.

* Fix tests.

* Update test/drafts/ERC777/ERC777.test.js

Co-Authored-By: nventuro <nicolas.venturo@gmail.com>

* Add changelog entry.

CHANGELOG.md

@@ -3,7 +3,9 @@
 ## 2.3.0 (unreleased)
 
 ### New features:
- * `ERC1820`: added support for interacting with the [ERC1820](https://eips.ethereum.org/EIPS/eip-1820) registry contract (`IERC1820Registry`), as well as base contracts that can be registered as implementers there. ([#1677](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1677))
+ * `ERC1820`: added support for interacting with the [ERC1820](https://eips.ethereum.org/EIPS/eip-1820) registry contract (`IERC1820Registry`), as well as base contracts that can be registered as
+ implementers there. ([#1677](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1677))
+ * `ERC777`: initial support for the [ERC777 token](https://eips.ethereum.org/EIPS/eip-777), which has multiple improvements over `ERC20` such as built-in burning, a more  straightforward permission system, and optional sender and receiver hooks on transfer (mandatory for contracts!). ([#1684](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1684))
 
 ## 2.2.0 (2019-03-14)
 

contracts/drafts/ERC777/IERC777.sol

+pragma solidity ^0.5.2;
+
+/**
+ * @title ERC777 token interface
+ * @dev See https://eips.ethereum.org/EIPS/eip-777
+ */
+interface IERC777 {
+    function authorizeOperator(address operator) external;
+
+    function revokeOperator(address operator) external;
+
+    function send(address to, uint256 amount, bytes calldata data) external;
+
+    function operatorSend(
+        address from,
+        address to,
+        uint256 amount,
+        bytes calldata data,
+        bytes calldata operatorData
+    ) external;
+
+    function burn(uint256 amount, bytes calldata data) external;
+
+    function operatorBurn(
+        address from,
+        uint256 amount,
+        bytes calldata data,
+        bytes calldata operatorData
+    ) external;
+
+    function name() external view returns (string memory);
+
+    function symbol() external view returns (string memory);
+
+    function totalSupply() external view returns (uint256);
+
+    function balanceOf(address owner) external view returns (uint256);
+
+    function granularity() external view returns (uint256);
+
+    function defaultOperators() external view returns (address[] memory);
+
+    function isOperatorFor(address operator, address tokenHolder) external view returns (bool);
+
+    event Sent(
+        address indexed operator,
+        address indexed from,
+        address indexed to,
+        uint256 amount,
+        bytes data,
+        bytes operatorData
+    );
+
+    event Minted(address indexed operator, address indexed to, uint256 amount, bytes data, bytes operatorData);
+
+    event Burned(address indexed operator, address indexed from, uint256 amount, bytes data, bytes operatorData);
+
+    event AuthorizedOperator(address indexed operator, address indexed tokenHolder);
+
+    event RevokedOperator(address indexed operator, address indexed tokenHolder);
+}

contracts/drafts/ERC777/IERC777Recipient.sol

+pragma solidity ^0.5.2;
+
+/**
+ * @title ERC777 token recipient interface
+ * @dev See https://eips.ethereum.org/EIPS/eip-777
+ */
+interface IERC777Recipient {
+    function tokensReceived(
+        address operator,
+        address from,
+        address to,
+        uint amount,
+        bytes calldata userData,
+        bytes calldata operatorData
+    ) external;
+}

contracts/drafts/ERC777/IERC777Sender.sol

+pragma solidity ^0.5.2;
+
+/**
+ * @title ERC777 token sender interface
+ * @dev See https://eips.ethereum.org/EIPS/eip-777
+ */
+interface IERC777Sender {
+    function tokensToSend(
+        address operator,
+        address from,
+        address to,
+        uint amount,
+        bytes calldata userData,
+        bytes calldata operatorData
+    ) external;
+}

contracts/mocks/ERC777Mock.sol

+pragma solidity ^0.5.2;
+
+import "../drafts/ERC777/ERC777.sol";
+
+contract ERC777Mock is ERC777 {
+    constructor(
+        address initialHolder,
+        uint256 initialBalance,
+        string memory name,
+        string memory symbol,
+        uint256 granularity,
+        address[] memory defaultOperators
+    ) public ERC777(name, symbol, granularity, defaultOperators) {
+        _mint(msg.sender, initialHolder, initialBalance, "", "");
+    }
+
+    function mintInternal (
+        address operator,
+        address to,
+        uint256 amount,
+        bytes memory userData,
+        bytes memory operatorData
+    ) public {
+        _mint(operator, to, amount, userData, operatorData);
+    }
+}

contracts/mocks/ERC777SenderRecipientMock.sol

+pragma solidity ^0.5.2;
+
+import "../drafts/ERC777/IERC777.sol";
+import "../drafts/ERC777/IERC777Sender.sol";
+import "../drafts/ERC777/IERC777Recipient.sol";
+import "../drafts/IERC1820Registry.sol";
+import "../drafts/ERC1820Implementer.sol";
+
+contract ERC777SenderRecipientMock is IERC777Sender, IERC777Recipient, ERC1820Implementer {
+    event TokensToSendCalled(
+        address operator,
+        address from,
+        address to,
+        uint256 amount,
+        bytes data,
+        bytes operatorData,
+        address token,
+        uint256 fromBalance,
+        uint256 toBalance
+    );
+
+    event TokensReceivedCalled(
+        address operator,
+        address from,
+        address to,
+        uint256 amount,
+        bytes data,
+        bytes operatorData,
+        address token,
+        uint256 fromBalance,
+        uint256 toBalance
+    );
+
+    bool private _shouldRevertSend;
+    bool private _shouldRevertReceive;
+
+    IERC1820Registry private _erc1820 = IERC1820Registry(0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24);
+
+    bytes32 constant private TOKENS_SENDER_INTERFACE_HASH = keccak256("ERC777TokensSender");
+    bytes32 constant private TOKENS_RECIPIENT_INTERFACE_HASH = keccak256("ERC777TokensRecipient");
+
+    function tokensToSend(
+        address operator,
+        address from,
+        address to,
+        uint amount,
+        bytes calldata userData,
+        bytes calldata operatorData
+    ) external {
+        if (_shouldRevertSend) {
+            revert();
+        }
+
+        IERC777 token = IERC777(msg.sender);
+
+        uint256 fromBalance = token.balanceOf(from);
+        // when called due to burn, to will be the zero address, which will have a balance of 0
+        uint256 toBalance = token.balanceOf(to);
+
+        emit TokensToSendCalled(
+            operator,
+            from,
+            to,
+            amount,
+            userData,
+            operatorData,
+            address(token),
+            fromBalance,
+            toBalance
+        );
+    }
+
+    function tokensReceived(
+        address operator,
+        address from,
+        address to,
+        uint amount,
+        bytes calldata userData,
+        bytes calldata operatorData
+    ) external{
+        if (_shouldRevertReceive) {
+            revert();
+        }
+
+        IERC777 token = IERC777(msg.sender);
+
+        uint256 fromBalance = token.balanceOf(from);
+        // when called due to burn, to will be the zero address, which will have a balance of 0
+        uint256 toBalance = token.balanceOf(to);
+
+        emit TokensReceivedCalled(
+            operator,
+            from,
+            to,
+            amount,
+            userData,
+            operatorData,
+            address(token),
+            fromBalance,
+            toBalance
+        );
+    }
+
+    function senderFor(address account) public {
+        _registerInterfaceForAddress(TOKENS_SENDER_INTERFACE_HASH, account);
+
+        address self = address(this);
+        if (account == self) {
+            registerSender(self);
+        }
+    }
+
+    function registerSender(address sender) public {
+        _erc1820.setInterfaceImplementer(address(this), TOKENS_SENDER_INTERFACE_HASH, sender);
+    }
+
+    function recipientFor(address account) public {
+        _registerInterfaceForAddress(TOKENS_RECIPIENT_INTERFACE_HASH, account);
+
+        address self = address(this);
+        if (account == self) {
+            registerRecipient(self);
+        }
+    }
+
+    function registerRecipient(address recipient) public {
+        _erc1820.setInterfaceImplementer(address(this), TOKENS_RECIPIENT_INTERFACE_HASH, recipient);
+    }
+
+    function setShouldRevertSend(bool shouldRevert) public {
+        _shouldRevertSend = shouldRevert;
+    }
+
+    function setShouldRevertReceive(bool shouldRevert) public {
+        _shouldRevertReceive = shouldRevert;
+    }
+
+    function send(IERC777 token, address to, uint256 amount, bytes memory data) public {
+        // This is 777's send function, not the Solidity send function
+        token.send(to, amount, data); // solhint-disable-line check-send-result
+    }
+
+    function burn(IERC777 token, uint256 amount, bytes memory data) public {
+        token.burn(amount, data);
+    }
+}
+

package.json

@@ -51,8 +51,8 @@
     "eslint-plugin-standard": "^3.1.0",
     "ethereumjs-util": "^6.0.0",
     "ganache-cli": "^6.4.1",
-    "ganache-cli-coverage": "github:Agusx1211/ganache-cli#c462b3fc48fe9b16756f7799885c0741114d9ed3",
-    "openzeppelin-test-helpers": "^0.3.0",
+    "ganache-cli-coverage": "https://github.com/frangio/ganache-cli/releases/download/v6.4.1-coverage/ganache-cli-coverage-6.4.1.tgz",
+    "openzeppelin-test-helpers": "^0.3.2",
     "solhint": "^1.5.0",
     "solidity-coverage": "github:rotcivegaf/solidity-coverage#5875f5b7bc74d447f3312c9c0e9fc7814b482477",
     "truffle": "^5.0.0"