#1 Added testing environment

#2 Added missing events
#3 bump up compiler version to 0.5.12(same with DAI)
#6 use enum to represent contract state
#7 Added methods to prevent "approve" race condition

.editorconfig

@@ -0,0 +1,15 @@
+root = true
+
+[*]
+end_of_line = lf
+indent_style = space
+indent_size = 4
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.js]
+indent_size = 2
+
+[{*.bat, *.ps1, *.ps2, Makefile, *.go}]
+indent_style = tab

.gitattributes

@@ -0,0 +1 @@
+*.sol linguist-language=Solidity

.gitignore

@@ -0,0 +1,17 @@
+### IDEs
+.idea
+.vscode
+
+### Temporary Files
+*.swp
+*.tmp
+*.log
+logs
+.DS_Store
+
+### Node.js
+node_modules
+
+### Buidler Files
+cache
+artifacts

.prettierignore

@@ -0,0 +1,17 @@
+### IDEs
+.idea
+.vscode
+
+### Temporary Files
+*.swp
+*.tmp
+*.log
+logs
+.DS_Store
+
+### Node.js
+node_modules
+
+### Buidler Files
+cache
+artifacts

buidler.config.js

@@ -0,0 +1,74 @@
+usePlugin('@nomiclabs/buidler-truffle5')
+
+const { toEthString } = require('./utils')
+
+const accountBalance = async account => {
+  const balance = await web3.eth.getBalance(account)
+  return [account, `${balance} Wei`, `${toEthString(balance)} Eth`]
+}
+
+// https://buidler.dev/guides/create-task.html
+task('accounts', 'Prints the list of accounts with their balances', async () => {
+  const accounts = await web3.eth.getAccounts()
+  await Promise.all(
+    accounts.map(async (account, index) => {
+      console.log([index, ...(await accountBalance(account).catch(err => [account, err.message]))].join('\t'))
+    })
+  )
+})
+
+task('balance', 'Prints the balance in each account')
+  .addVariadicPositionalParam('accounts', 'ETH address(es)', undefined, undefined, false)
+  .setAction(async taskArgs =>
+    Promise.all(
+      taskArgs.accounts.map(async (account, index) => {
+        console.log([index, ...(await accountBalance(account).catch(err => [account, err.message]))].join('\t'))
+      })
+    )
+  )
+
+task('info', 'Prints current network info', async () => {
+  const getters = {
+    provider: async () => web3.currentProvider._provider._url,
+    chainId: web3.eth.getChainId,
+    networkType: web3.eth.net.getNetworkType,
+    blockNumber: web3.eth.getBlockNumber,
+  }
+
+  await Promise.all(
+    Object.entries(getters).map(async ([field, valueGetter]) => {
+      console.log(`${field}: ${await valueGetter().catch(err => err.message)}`)
+    })
+  )
+})
+
+task('tx', 'Find and prints the transaction with given txid')
+  .addPositionalParam('txid', 'Transaction ID', undefined, undefined, false)
+  .setAction(async taskArgs => {
+    console.log(await web3.eth.getTransaction(taskArgs.txid))
+  })
+
+// You have to export an object to set up your config
+// This object can have the following optional entries:
+// defaultNetwork, networks, solc, and paths.
+// Go to https://buidler.dev/config/ to learn more
+module.exports = {
+  defaultNetwork: 'buidlerevm',
+  solc: {
+    version: '0.5.12',
+    optimizer: { enabled: true, runs: 200 },
+  },
+  // networks: {
+  //   ropsten: {
+  //     chainId: 3,
+  //     url: 'https://provider-url.somewhere.you.know',
+  //     gasMultiplier: 1.2,
+  //     accounts: {
+  //       mnemonic: 'some mnemonics here if you really want to do use slow ropsten testing',
+  //       path: `m/44'/60'/0'/0`,
+  //       initialIndex: 0,
+  //       count: 4,
+  //     },
+  //   },
+  // },
+}

contracts/DaiProxy.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.5.0;
+pragma solidity ^0.5.12;
 
 contract ReserveLike {
     function depositToken(address, address, uint, address) public;
@@ -49,7 +49,7 @@ contract VatLike {
 }
 
 contract DaiProxy {
-    string public constant version = "0401";
+    string public constant version = "0511";
 
     // --- Owner ---
     address public owner;
@@ -67,15 +67,17 @@ contract DaiProxy {
     }
 
     // --- State ---
-    uint public state = 0;  // 0 : 시작 전, 1 : 작동 중, 2 : 사망
+    enum State { Ready, Running, Killed }
+
+    State public state = State.Ready;
 
     modifier notStarted {
-        require(state == 0);
+        require(state == State.Ready);
         _;
     }
 
     modifier notPaused {
-        require(state == 1);
+        require(state == State.Running);
         _;
     }
 
@@ -153,6 +155,8 @@ contract DaiProxy {
     WrappedDaiLike public EDai;
     WrappedDaiLike public ODai;
 
+    event SetReserve(address reserve);
+
     constructor(address dai, address join, address pot, address vat, address eDai, address oDai) public {
         owner = msg.sender;
 
@@ -186,6 +190,8 @@ contract DaiProxy {
         // approve for Reserve.depositToken
         require(EDai.approve(reserve, uint(-1)));
         require(ODai.approve(reserve, uint(-1)));
+
+        emit SetReserve(reserve);
     }
 
     modifier onlyEDai {
@@ -317,6 +323,10 @@ contract DaiProxy {
     // --- Migration ---
     DaiProxy public NewProxy;
 
+    event SetNewProxy(address proxy);
+    event StartProxy(address prev);
+    event KillProxy(address next, bool mig);
+
     modifier onlyNewProxy {
         require(msg.sender == address(NewProxy));
         _;
@@ -325,21 +335,24 @@ contract DaiProxy {
     // 새로운 프록시가 발행되었음을 알린다
     function setNewProxy(address proxy) public onlyOwner {
         NewProxy = DaiProxy(proxy);
+        emit SetNewProxy(proxy);
     }
 
     // 프록시의 작동을 완전히 중지하고 돈을 전부 다른 지갑으로 옮긴다
     function killProxy(address to) public notPaused onlyOwner {
-        state = 2;
+        state = State.Killed;
 
         chi();
 
         Pot.exit(Pot.pie(address(this)));
         Join.exit(to, Vat.dai(address(this)) / ONE);
+
+        emit KillProxy(to, false);
     }
 
     // 새로 생긴 프록시로 자산을 옮긴다.
     function migrateProxy() public notPaused onlyNewProxy {
-        state = 2;
+        state = State.Killed;
 
         EDai.setProxy(address(NewProxy));
         ODai.setProxy(address(NewProxy));
@@ -348,17 +361,21 @@ contract DaiProxy {
 
         Pot.exit(Pot.pie(address(this)));
         Vat.move(address(this), address(NewProxy), Vat.dai(address(this)));
+
+        emit KillProxy(address(NewProxy), true);
     }
 
     // 프록시를 켠다.
     function startProxy(address oldProxy) public notStarted onlyOwner {
-        state = 1;
+        state = State.Running;
 
         if (oldProxy != address(0)) {
             DaiProxy(oldProxy).migrateProxy();
 
             uint vat = Vat.dai(address(this));
             Pot.join(div(vat, chi()));
         }
+
+        emit StartProxy(oldProxy);
     }
 }

contracts/OrbitDai.sol

@@ -1,4 +1,4 @@
-pragma solidity ^0.5.0;
+pragma solidity ^0.5.12;
 
 contract ReserveLike {
 }
@@ -9,7 +9,7 @@ contract ProxyLike {
 }
 
 contract WrappedDai {
-    string public constant version = "0327";
+    string public constant version = "0511";
 
     // --- Owner ---
     address public owner;
@@ -40,6 +40,8 @@ contract WrappedDai {
     // --- Proxy ---
     ProxyLike public Proxy;
 
+    event SetProxy(address proxy);
+
     modifier onlyProxy {
         require(msg.sender == address(Proxy));
         _;
@@ -51,20 +53,26 @@ contract WrappedDai {
     }
 
     // 최초 발행 시에는 Owner, 그 뒤에는 Proxy가 호출
-    function setProxy(address _proxy) public onlyOwnerOrProxy {
-        Proxy = ProxyLike(_proxy);
+    function setProxy(address proxy) public onlyOwnerOrProxy {
+        Proxy = ProxyLike(proxy);
+        emit SetProxy(proxy);
     }
 
     // --- Contracts & Constructor ---
     ReserveLike public Reserve;
     uint public reserveLimit;
 
+    event SetReserve(address reserve);
+    event SetReserveLimit(uint limit);
+
     function setReserve(address reserve) public onlyProxy {
         Reserve = ReserveLike(reserve);
+        emit SetReserve(reserve);
     }
 
     function setReserveLimit(uint limit) public onlyOwner {
         reserveLimit = limit;
+        emit SetReserveLimit(limit);
     }
 
     constructor() public {
@@ -104,6 +112,29 @@ contract WrappedDai {
         return true;
     }
 
+    function increaseApproval(address spender, uint amount) public returns (bool) {
+        amount = add(allowance[msg.sender][spender], amount);
+
+        allowance[msg.sender][spender] = amount;
+        emit Approval(msg.sender, spender, amount);
+
+        return true;
+    }
+
+    function decreaseApproval(address spender, uint amount) public returns (bool) {
+        if (amount > allowance[msg.sender][spender]) {
+            amount = 0;
+        }
+        else {
+            amount = allowance[msg.sender][spender] - amount;
+        }
+
+        allowance[msg.sender][spender] = amount;
+        emit Approval(msg.sender, spender, amount);
+
+        return true;
+    }
+
     function mint(address user, uint amount) public onlyProxy {
         balanceOf[user] = add(balanceOf[user], amount);
         totalSupply = add(totalSupply, amount);

package.json

@@ -0,0 +1,34 @@
+{
+  "name": "ethereum-orbit-dai",
+  "version": "1.0.0",
+  "private": true,
+  "description": "Ethereum Orbit Dai",
+  "repository": "https://github.com/orbit-chain/ethereum-orbit-dai.git",
+  "license": "UNLICENSED",
+  "main": "index.js",
+  "scripts": {
+    "clean": "buidler clean",
+    "compile": "buidler compile",
+    "lint": "prettier -c **/*.js package.json",
+    "lint:fix": "prettier **/*.js package.json --write",
+    "test": "buidler test"
+  },
+  "prettier": {
+    "arrowParens": "avoid",
+    "endOfLine": "lf",
+    "printWidth": 120,
+    "semi": false,
+    "singleQuote": true,
+    "tabWidth": 2,
+    "trailingComma": "es5",
+    "useTabs": false
+  },
+  "dependencies": {
+    "@nomiclabs/buidler": "^1.3.2",
+    "@nomiclabs/buidler-truffle5": "^1.3.2",
+    "@nomiclabs/buidler-web3": "^1.3.2",
+    "prettier": "^2.0.5",
+    "prettier-plugin-packagejson": "^2.2.3",
+    "web3": "^1.2.7"
+  }
+}