Merge branch 'v2-prototype' into v2-contract-wrappers-WIP

2 files changed, 122 insertions, 2 deletions

diff --git a/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
index a88745485..7895a42ee 100644
--- a/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
@@ -2,7 +2,7 @@ import { ContractArtifact } from '@0xproject/sol-compiler';
 import { AbiDecoder, intervalUtils } from '@0xproject/utils';
 import { Web3Wrapper } from '@0xproject/web3-wrapper';
 import { BlockParamLiteral, ContractAbi, FilterObject, LogEntry, LogWithDecodedArgs, RawLog } from 'ethereum-types';
-import { Block, BlockAndLogStreamer } from 'ethereumjs-blockstream';
+import { Block, BlockAndLogStreamer, Log } from 'ethereumjs-blockstream';
 import * as _ from 'lodash';
 
 import {
@@ -33,7 +33,7 @@ export abstract class ContractWrapper {
     public abstract abi: ContractAbi;
     protected _web3Wrapper: Web3Wrapper;
     protected _networkId: number;
-    private _blockAndLogStreamerIfExists?: BlockAndLogStreamer;
+    private _blockAndLogStreamerIfExists: BlockAndLogStreamer<Block, Log> | undefined;
     private _blockAndLogStreamIntervalIfExists?: NodeJS.Timer;
     private _filters: { [filterToken: string]: FilterObject };
     private _filterCallbacks: {
@@ -155,6 +155,7 @@ export abstract class ContractWrapper {
         this._blockAndLogStreamerIfExists = new BlockAndLogStreamer(
             this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper),
             this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper),
+            this._onBlockAndLogStreamerError.bind(this),
         );
         const catchAllLogFilter = {};
         this._blockAndLogStreamerIfExists.addLogFilter(catchAllLogFilter);
@@ -172,6 +173,14 @@ export abstract class ContractWrapper {
             this._onLogStateChanged.bind(this, isRemoved),
         );
     }
+    private _onBlockAndLogStreamerError(err: Error): void {
+        // Propogate all Blockstream subscriber errors to all
+        // top-level subscriptions
+        const filterCallbacks = _.values(this._filterCallbacks);
+        _.each(filterCallbacks, filterCallback => {
+            filterCallback(err);
+        });
+    }
     private _onReconcileBlockError(err: Error): void {
         const filterTokens = _.keys(this._filterCallbacks);
         _.each(filterTokens, filterToken => {
diff --git a/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
new file mode 100644
index 000000000..279f2a796
--- /dev/null
+++ b/packages/contract-wrappers/src/utils/exchange_transfer_simulator.ts
@@ -0,0 +1,111 @@
+import { ExchangeContractErrs } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+
+import { AbstractBalanceAndProxyAllowanceLazyStore } from '../abstract/abstract_balance_and_proxy_allowance_lazy_store';
+import { TradeSide, TransferType } from '../types';
+import { constants } from '../utils/constants';
+
+enum FailureReason {
+    Balance = 'balance',
+    ProxyAllowance = 'proxyAllowance',
+}
+
+const ERR_MSG_MAPPING = {
+    [FailureReason.Balance]: {
+        [TradeSide.Maker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientMakerBalance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeBalance,
+        },
+        [TradeSide.Taker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientTakerBalance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeBalance,
+        },
+    },
+    [FailureReason.ProxyAllowance]: {
+        [TradeSide.Maker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientMakerAllowance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientMakerFeeAllowance,
+        },
+        [TradeSide.Taker]: {
+            [TransferType.Trade]: ExchangeContractErrs.InsufficientTakerAllowance,
+            [TransferType.Fee]: ExchangeContractErrs.InsufficientTakerFeeAllowance,
+        },
+    },
+};
+
+export class ExchangeTransferSimulator {
+    private _store: AbstractBalanceAndProxyAllowanceLazyStore;
+    private static _throwValidationError(
+        failureReason: FailureReason,
+        tradeSide: TradeSide,
+        transferType: TransferType,
+    ): never {
+        const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
+        throw new Error(errMsg);
+    }
+    constructor(store: AbstractBalanceAndProxyAllowanceLazyStore) {
+        this._store = store;
+    }
+    /**
+     * Simulates transferFrom call performed by a proxy
+     * @param  tokenAddress      Address of the token to be transferred
+     * @param  from              Owner of the transferred tokens
+     * @param  to                Recipient of the transferred tokens
+     * @param  amountInBaseUnits The amount of tokens being transferred
+     * @param  tradeSide         Is Maker/Taker transferring
+     * @param  transferType      Is it a fee payment or a value transfer
+     */
+    public async transferFromAsync(
+        tokenAddress: string,
+        from: string,
+        to: string,
+        amountInBaseUnits: BigNumber,
+        tradeSide: TradeSide,
+        transferType: TransferType,
+    ): Promise<void> {
+        // HACK: When simulating an open order (e.g taker is NULL_ADDRESS), we don't want to adjust balances/
+        // allowances for the taker. We do however, want to increase the balance of the maker since the maker
+        // might be relying on those funds to fill subsequent orders or pay the order's fees.
+        if (from === constants.NULL_ADDRESS && tradeSide === TradeSide.Taker) {
+            await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
+            return;
+        }
+        const balance = await this._store.getBalanceAsync(tokenAddress, from);
+        const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, from);
+        if (proxyAllowance.lessThan(amountInBaseUnits)) {
+            ExchangeTransferSimulator._throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
+        }
+        if (balance.lessThan(amountInBaseUnits)) {
+            ExchangeTransferSimulator._throwValidationError(FailureReason.Balance, tradeSide, transferType);
+        }
+        await this._decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits);
+        await this._decreaseBalanceAsync(tokenAddress, from, amountInBaseUnits);
+        await this._increaseBalanceAsync(tokenAddress, to, amountInBaseUnits);
+    }
+    private async _decreaseProxyAllowanceAsync(
+        tokenAddress: string,
+        userAddress: string,
+        amountInBaseUnits: BigNumber,
+    ): Promise<void> {
+        const proxyAllowance = await this._store.getProxyAllowanceAsync(tokenAddress, userAddress);
+        if (!proxyAllowance.eq(constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS)) {
+            this._store.setProxyAllowance(tokenAddress, userAddress, proxyAllowance.minus(amountInBaseUnits));
+        }
+    }
+    private async _increaseBalanceAsync(
+        tokenAddress: string,
+        userAddress: string,
+        amountInBaseUnits: BigNumber,
+    ): Promise<void> {
+        const balance = await this._store.getBalanceAsync(tokenAddress, userAddress);
+        this._store.setBalance(tokenAddress, userAddress, balance.plus(amountInBaseUnits));
+    }
+    private async _decreaseBalanceAsync(
+        tokenAddress: string,
+        userAddress: string,
+        amountInBaseUnits: BigNumber,
+    ): Promise<void> {
+        const balance = await this._store.getBalanceAsync(tokenAddress, userAddress);
+        this._store.setBalance(tokenAddress, userAddress, balance.minus(amountInBaseUnits));
+    }
+}