add pauseDeposits

.env.example

@@ -3,4 +3,5 @@ MERKLE_TREE_HEIGHT=16
 AMOUNT=1000000000000000000
 EMPTY_ELEMENT=1337
 PRIVATE_KEY=
+PAUSEACCOUNT=0x17017Ba4FA022299067B5F235e2F230973bc7Fed
 

.gitignore

@@ -1,6 +1,7 @@
 build
 .vscode
 /index.js
+Mixer_flat.sol
 
 # Created by .ignore support plugin (hsz.mobi)
 ### Node template

.solhint.json

@@ -0,0 +1,6 @@
+{
+  "extends": "solhint:recommended",
+  "rules": {
+    "indent": ["error", 2]
+  }
+}

contracts/Mixer.sol

@@ -8,6 +8,8 @@ contract IVerifier {
 
 contract Mixer is MerkleTreeWithHistory {
   uint256 public transferValue;
+  bool public isDepositsEnabled = true;
+  address public pauseAccount;
   mapping(uint256 => bool) public nullifierHashes;
   // we store all commitments just to prevent accidental deposits with the same commitment
   mapping(uint256 => bool) public commitments;
@@ -25,10 +27,12 @@ contract Mixer is MerkleTreeWithHistory {
     address _verifier,
     uint256 _transferValue,
     uint8 _merkleTreeHeight,
-    uint256 _emptyElement
+    uint256 _emptyElement,
+    address _pauseAccount
   ) MerkleTreeWithHistory(_merkleTreeHeight, _emptyElement) public {
     verifier = IVerifier(_verifier);
     transferValue = _transferValue;
+    pauseAccount = _pauseAccount;
   }
 
   /**
@@ -36,6 +40,7 @@ contract Mixer is MerkleTreeWithHistory {
     @param commitment the note commitment, which is PedersenHash(nullifier + secret)
   */
   function deposit(uint256 commitment) public payable {
+    require(isDepositsEnabled, "deposits disabled");
     require(msg.value == transferValue, "Please send `transferValue` ETH along with transaction");
     require(!commitments[commitment], "The commitment has been submitted");
     _insert(commitment);
@@ -70,6 +75,11 @@ contract Mixer is MerkleTreeWithHistory {
     emit Withdraw(receiver, nullifierHash, fee);
   }
 
+  function toggleDeposits() external {
+    require(msg.sender == pauseAccount, "unauthorized");
+    isDepositsEnabled = !isDepositsEnabled;
+  }
+
   function isSpent(uint256 nullifier) public view returns(bool) {
     return nullifierHashes[nullifier];
   }

migrations/4_deploy_mixer.js

@@ -5,13 +5,13 @@ const Verifier = artifacts.require('Verifier')
 const MiMC = artifacts.require('MiMC')
 
 
-module.exports = function(deployer) {
+module.exports = function(deployer, network, accounts) {
   return deployer.then(async () => {
     const { MERKLE_TREE_HEIGHT, AMOUNT, EMPTY_ELEMENT } = process.env
     const verifier = await Verifier.deployed()
     const miMC = await MiMC.deployed()
     await Mixer.link(MiMC, miMC.address)
-    const mixer = await deployer.deploy(Mixer, verifier.address, AMOUNT, MERKLE_TREE_HEIGHT, EMPTY_ELEMENT)
+    const mixer = await deployer.deploy(Mixer, verifier.address, AMOUNT, MERKLE_TREE_HEIGHT, EMPTY_ELEMENT, accounts[0])
     console.log('Mixer\'s address ', mixer.address)
   })
 }

package.json

@@ -14,7 +14,8 @@
     "migrate": "npx truffle migrate --network kovan --reset",
     "migrate:dev": "npx truffle migrate --network development --reset",
     "browserify": "npx browserify cli.js -o index.js --exclude worker_threads",
-    "eslint": "npx eslint --ignore-path .gitignore ."
+    "eslint": "npx eslint --ignore-path .gitignore .",
+    "flat": "truffle-flattener contracts/Mixer.sol > Mixer_flat.sol"
   },
   "keywords": [],
   "author": "",
@@ -38,5 +39,8 @@
     "web3": "^1.0.0-beta.55",
     "web3-utils": "^1.0.0-beta.55",
     "websnark": "git+https://github.com/poma/websnark.git#271c74a76f4d9277c049283c45929fb3a5bb46fc"
+  },
+  "devDependencies": {
+    "truffle-flattener": "^1.4.0"
   }
 }

test/Mixer.test.js

@@ -111,6 +111,17 @@ contract('Mixer', accounts => {
       logs[0].args.leafIndex.should.be.eq.BN(toBN(1))
     })
 
+    it('should not deposit if disabled', async () => {
+      let commitment = 42;
+      (await mixer.isDepositsEnabled()).should.be.equal(true)
+      const err = await mixer.toggleDeposits({ from: accounts[1] }).should.be.rejected
+      err.reason.should.be.equal('unauthorized')
+      await mixer.toggleDeposits({ from: sender });
+      (await mixer.isDepositsEnabled()).should.be.equal(false)
+      let error = await mixer.deposit(commitment, { value, from: sender }).should.be.rejected
+      error.reason.should.be.equal('deposits disabled')
+    })
+
     it('should throw if there is a such commitment', async () => {
       const commitment = 42
       await mixer.deposit(commitment, { value, from: sender }).should.be.fulfilled

truffle-config.js

@@ -72,7 +72,7 @@ module.exports = {
       // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
       settings: {          // See the solidity docs for advice about optimization and evmVersion
         optimizer: {
-          enabled: false,
+          enabled: true,
           runs: 200
         },
         // evmVersion: "byzantium"