1 files changed, 109 insertions, 0 deletions
diff --git a/packages/contracts/util/order.ts b/packages/contracts/util/order.ts
new file mode 100644
index 000000000..635999348
--- /dev/null
+++ b/packages/contracts/util/order.ts
@@ -0,0 +1,109 @@
+import {BigNumber} from 'bignumber.js';
+import promisify = require('es6-promisify');
+import ethUtil = require('ethereumjs-util');
+import * as _ from 'lodash';
+import Web3 = require('web3');
+
+import {crypto} from './crypto';
+import {OrderParams} from './types';
+
+// In order to benefit from type-safety, we re-assign the global web3 instance injected by Truffle
+// with type `any` to a variable of type `Web3`.
+const web3: Web3 = (global as any).web3;
+
+export class Order {
+  public params: OrderParams;
+  constructor(params: OrderParams) {
+    this.params = params;
+  }
+  public isValidSignature() {
+    const {v, r, s} = this.params;
+    if (_.isUndefined(v) || _.isUndefined(r) || _.isUndefined(s)) {
+      throw new Error('Cannot call isValidSignature on unsigned order');
+    }
+    const orderHash = this.getOrderHash();
+    const msgHash = ethUtil.hashPersonalMessage(ethUtil.toBuffer(orderHash));
+    try {
+      const pubKey = ethUtil.ecrecover(msgHash, v, ethUtil.toBuffer(r), ethUtil.toBuffer(s));
+      const recoveredAddress = ethUtil.bufferToHex(ethUtil.pubToAddress(pubKey));
+      return recoveredAddress === this.params.maker;
+    } catch (err) {
+      return false;
+    }
+  }
+  public async signAsync() {
+    const orderHash = this.getOrderHash();
+    const signature = await promisify(web3.eth.sign)(this.params.maker, orderHash);
+    const {v, r, s} = ethUtil.fromRpcSig(signature);
+    this.params = _.assign(this.params, {
+      orderHashHex: orderHash,
+      v,
+      r: ethUtil.bufferToHex(r),
+      s: ethUtil.bufferToHex(s),
+    });
+  }
+  public createFill(shouldThrowOnInsufficientBalanceOrAllowance?: boolean, fillTakerTokenAmount?: BigNumber) {
+    const fill = {
+      orderAddresses: [
+        this.params.maker,
+        this.params.taker,
+        this.params.makerToken,
+        this.params.takerToken,
+        this.params.feeRecipient,
+      ],
+      orderValues: [
+        this.params.makerTokenAmount,
+        this.params.takerTokenAmount,
+        this.params.makerFee,
+        this.params.takerFee,
+        this.params.expirationTimestampInSec,
+        this.params.salt,
+      ],
+      fillTakerTokenAmount: fillTakerTokenAmount || this.params.takerTokenAmount,
+      shouldThrowOnInsufficientBalanceOrAllowance: !!shouldThrowOnInsufficientBalanceOrAllowance,
+      v: this.params.v,
+      r: this.params.r,
+      s: this.params.s,
+    };
+    return fill;
+  }
+  public createCancel(cancelTakerTokenAmount?: BigNumber) {
+    const cancel = {
+      orderAddresses: [
+        this.params.maker,
+        this.params.taker,
+        this.params.makerToken,
+        this.params.takerToken,
+        this.params.feeRecipient,
+      ],
+      orderValues: [
+        this.params.makerTokenAmount,
+        this.params.takerTokenAmount,
+        this.params.makerFee,
+        this.params.takerFee,
+        this.params.expirationTimestampInSec,
+        this.params.salt,
+      ],
+      cancelTakerTokenAmount: cancelTakerTokenAmount || this.params.takerTokenAmount,
+    };
+    return cancel;
+  }
+  private getOrderHash(): string {
+    const orderHash = crypto.solSHA3([
+      this.params.exchangeContractAddress,
+      this.params.maker,
+      this.params.taker,
+      this.params.makerToken,
+      this.params.takerToken,
+      this.params.feeRecipient,
+      this.params.makerTokenAmount,
+      this.params.takerTokenAmount,
+      this.params.makerFee,
+      this.params.takerFee,
+      this.params.expirationTimestampInSec,
+      this.params.salt,
+    ]);
+    const orderHashHex = ethUtil.bufferToHex(orderHash);
+    return orderHashHex;
+  }
+}