From 685d2087caeb52e6d1f868b9bcce404cae3e315f Mon Sep 17 00:00:00 2001
From: AugustoL <augusto.lemble@gmail.com>
Date: Mon, 15 Jan 2018 20:56:25 -0300
Subject: [PATCH] Add increase and decrease approval functions to ERC827 with
 tests

---
 contracts/token/ERC827.sol | 44 +++++++++++++++++++++++++++++
 test/ERC827Token.js        | 58 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/contracts/token/ERC827.sol b/contracts/token/ERC827.sol
index d07f65e83..472b82b07 100644
--- a/contracts/token/ERC827.sol
+++ b/contracts/token/ERC827.sol
@@ -78,4 +78,48 @@ contract ERC827 is StandardToken {
     return true;
   }
 
+  /**
+   * @dev Addition to StandardToken methods. Increase the amount of tokens that
+   * an owner allowed to a spender and execute a call with the sent data.
+   *
+   * approve should be called when allowed[_spender] == 0. To increment
+   * allowed value is better to use this function to avoid 2 calls (and wait until
+   * the first transaction is mined)
+   * From MonolithDAO Token.sol
+   * @param _spender The address which will spend the funds.
+   * @param _addedValue The amount of tokens to increase the allowance by.
+   * @param _data ABI-encoded contract call to call `_spender` address.
+   */
+  function increaseApproval(address _spender, uint _addedValue, bytes _data) public returns (bool) {
+    require(_spender != address(this));
+
+    super.approve(_spender, _addedValue);
+
+    require(_spender.call(_data));
+
+    return true;
+  }
+
+  /**
+   * @dev Addition to StandardToken methods. Decrease the amount of tokens that
+   * an owner allowed to a spender and execute a call with the sent data.
+   *
+   * approve should be called when allowed[_spender] == 0. To decrement
+   * allowed value is better to use this function to avoid 2 calls (and wait until
+   * the first transaction is mined)
+   * From MonolithDAO Token.sol
+   * @param _spender The address which will spend the funds.
+   * @param _subtractedValue The amount of tokens to decrease the allowance by.
+   * @param _data ABI-encoded contract call to call `_spender` address.
+   */
+  function decreaseApproval(address _spender, uint _subtractedValue, bytes _data) public returns (bool) {
+    require(_spender != address(this));
+
+    super.decreaseApproval(_spender, _subtractedValue);
+
+    require(_spender.call(_data));
+
+    return true;
+  }
+
 }
diff --git a/test/ERC827Token.js b/test/ERC827Token.js
index 08902f449..7cb4ed26c 100644
--- a/test/ERC827Token.js
+++ b/test/ERC827Token.js
@@ -94,7 +94,13 @@ contract('ERC827 Token', function (accounts) {
     });
 
     it('should increase by 50 then decrease by 10', async function () {
-      await token.increaseApproval(accounts[1], 50);
+      const abiMethod = findMethod(token.abi, 'increaseApproval', 'address,uint256');
+      const increaseApprovalData = ethjsABI.encodeMethod(abiMethod,
+        [accounts[1], 50]
+      );
+      await token.sendTransaction(
+        { from: accounts[0], data: increaseApprovalData }
+      );
       let postIncrease = await token.allowance(accounts[0], accounts[1]);
       preApproved.plus(50).should.be.bignumber.equal(postIncrease);
       await token.decreaseApproval(accounts[1], 10);
@@ -168,6 +174,56 @@ contract('ERC827 Token', function (accounts) {
         );
       });
 
+    it(
+      'should return correct allowance after increaseApproval (with data) and show the event on receiver contract'
+      , async function () {
+        const message = await Message.new();
+
+        const extraData = message.contract.showMessage.getData(
+          web3.toHex(123456), 666, 'Transfer Done'
+        );
+
+        const abiMethod = findMethod(token.abi, 'increaseApproval', 'address,uint256,bytes');
+        const increaseApprovalData = ethjsABI.encodeMethod(abiMethod,
+          [message.contract.address, 50, extraData]
+        );
+        const transaction = await token.sendTransaction(
+          { from: accounts[0], data: increaseApprovalData }
+        );
+
+        assert.equal(2, transaction.receipt.logs.length);
+
+        new BigNumber(50).should.be.bignumber.equal(
+          await token.allowance(accounts[0], message.contract.address)
+        );
+      });
+
+    it(
+      'should return correct allowance after decreaseApproval (with data) and show the event on receiver contract'
+      , async function () {
+        const message = await Message.new();
+
+        await token.approve(message.contract.address, 100);
+
+        const extraData = message.contract.showMessage.getData(
+          web3.toHex(123456), 666, 'Transfer Done'
+        );
+
+        const abiMethod = findMethod(token.abi, 'decreaseApproval', 'address,uint256,bytes');
+        const decreaseApprovalData = ethjsABI.encodeMethod(abiMethod,
+          [message.contract.address, 60, extraData]
+        );
+        const transaction = await token.sendTransaction(
+          { from: accounts[0], data: decreaseApprovalData }
+        );
+
+        assert.equal(2, transaction.receipt.logs.length);
+
+        new BigNumber(40).should.be.bignumber.equal(
+          await token.allowance(accounts[0], message.contract.address)
+        );
+      });
+
     it(
       'should return correct balances after transferFrom (with data) and show the event on receiver contract'
       , async function () {