Merge pull request #81 from 0xProject/addWrappedETHSupport

Add Wrapped ETH Support

2 files changed, 76 insertions, 0 deletions

diff --git a/src/contract_wrappers/ether_token_wrapper.ts b/src/contract_wrappers/ether_token_wrapper.ts
new file mode 100644
index 000000000..76e7289b7
--- /dev/null
+++ b/src/contract_wrappers/ether_token_wrapper.ts
@@ -0,0 +1,75 @@
+import * as _ from 'lodash';
+import {Web3Wrapper} from '../web3_wrapper';
+import {ContractWrapper} from './contract_wrapper';
+import {TokenWrapper} from './token_wrapper';
+import {EtherTokenContract, ZeroExError} from '../types';
+import {assert} from '../utils/assert';
+import * as EtherTokenArtifacts from '../artifacts/EtherToken.json';
+
+/**
+ * This class includes all the functionality related to interacting with a wrapped Ether ERC20 token contract.
+ * The caller can convert ETH into the equivalent number of wrapped ETH ERC20 tokens and back.
+ */
+export class EtherTokenWrapper extends ContractWrapper {
+    private _etherTokenContractIfExists?: EtherTokenContract;
+    private _tokenWrapper: TokenWrapper;
+    constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper) {
+        super(web3Wrapper);
+        this._tokenWrapper = tokenWrapper;
+    }
+    /**
+     * Deposit ETH into the Wrapped ETH smart contract and issues the equivalent number of wrapped ETH tokens
+     * to the depositor address. These wrapped ETH tokens can be used in 0x trades and are redeemable for 1-to-1
+     * for ETH.
+     * @param   amountInWei      Amount of ETH in Wei the caller wishes to deposit.
+     * @param   depositor   The hex encoded user Ethereum address that would like to make the deposit.
+     */
+    public async depositAsync(amountInWei: BigNumber.BigNumber, depositor: string): Promise<void> {
+        assert.isBigNumber('amountInWei', amountInWei);
+        await assert.isSenderAddressAsync('depositor', depositor, this._web3Wrapper);
+
+        const ethBalanceInWei = await this._web3Wrapper.getBalanceInWeiAsync(depositor);
+        assert.assert(ethBalanceInWei.gte(amountInWei), ZeroExError.INSUFFICIENT_ETH_BALANCE_FOR_DEPOSIT);
+
+        const wethContract = await this._getEtherTokenContractAsync();
+        await wethContract.deposit({
+            from: depositor,
+            value: amountInWei,
+        });
+    }
+    /**
+     * Withdraw ETH to the withdrawer's address from the wrapped ETH smart contract in exchange for the
+     * equivalent number of wrapped ETH tokens.
+     * @param   amountInWei  Amount of ETH in Wei the caller wishes to withdraw.
+     * @param   withdrawer   The hex encoded user Ethereum address that would like to make the withdrawl.
+     */
+    public async withdrawAsync(amountInWei: BigNumber.BigNumber, withdrawer: string): Promise<void> {
+        assert.isBigNumber('amountInWei', amountInWei);
+        await assert.isSenderAddressAsync('withdrawer', withdrawer, this._web3Wrapper);
+
+        const wethContractAddress = await this.getContractAddressAsync();
+        const WETHBalanceInBaseUnits = await this._tokenWrapper.getBalanceAsync(wethContractAddress, withdrawer);
+        assert.assert(WETHBalanceInBaseUnits.gte(amountInWei), ZeroExError.INSUFFICIENT_WETH_BALANCE_FOR_WITHDRAWAL);
+
+        const wethContract = await this._getEtherTokenContractAsync();
+        await wethContract.withdraw(amountInWei, {
+            from: withdrawer,
+        });
+    }
+    /**
+     * Retrieves the Wrapped Ether token contract address
+     * @return  The Wrapped Ether token contract address
+     */
+    public async getContractAddressAsync(): Promise<string> {
+        const wethContract = await this._getEtherTokenContractAsync();
+        return wethContract.address;
+    }
+    private async _getEtherTokenContractAsync(): Promise<EtherTokenContract> {
+        if (!_.isUndefined(this._etherTokenContractIfExists)) {
+            return this._etherTokenContractIfExists;
+        }
+        const contractInstance = await this._instantiateContractIfExistsAsync((EtherTokenArtifacts as any));
+        this._etherTokenContractIfExists = contractInstance as EtherTokenContract;
+        return this._etherTokenContractIfExists;
+    }
+}
diff --git a/src/contract_wrappers/token_wrapper.ts b/src/contract_wrappers/token_wrapper.ts
index 29f9b2d1c..e34c624ab 100644
--- a/src/contract_wrappers/token_wrapper.ts
+++ b/src/contract_wrappers/token_wrapper.ts
@@ -28,6 +28,7 @@ export class TokenWrapper extends ContractWrapper {
      * Retrieves an owner's ERC20 token balance.
      * @param   tokenAddress    The hex encoded contract Ethereum address where the ERC20 token is deployed.
      * @param   ownerAddress    The hex encoded user Ethereum address whose balance you would like to check.
+     * @return  The owner's ERC20 token balance in base units.
      */
     public async getBalanceAsync(tokenAddress: string, ownerAddress: string): Promise<BigNumber.BigNumber> {
         assert.isETHAddressHex('ownerAddress', ownerAddress);