1 files changed, 208 insertions, 0 deletions
diff --git a/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
new file mode 100644
index 000000000..f255ced62
--- /dev/null
+++ b/packages/contract-wrappers/src/contract_wrappers/contract_wrapper.ts
@@ -0,0 +1,208 @@
+import {
+    Artifact,
+    BlockParamLiteral,
+    ContractAbi,
+    FilterObject,
+    LogEntry,
+    LogWithDecodedArgs,
+    RawLog,
+} from '@0xproject/types';
+import { AbiDecoder, intervalUtils } from '@0xproject/utils';
+import { Web3Wrapper } from '@0xproject/web3-wrapper';
+import { Block, BlockAndLogStreamer } from 'ethereumjs-blockstream';
+import * as _ from 'lodash';
+
+import {
+    BlockRange,
+    ContractEventArgs,
+    ContractEvents,
+    ContractWrappersError,
+    EventCallback,
+    IndexedFilterValues,
+    InternalContractWrappersError,
+} from '../types';
+import { constants } from '../utils/constants';
+import { filterUtils } from '../utils/filter_utils';
+
+const CONTRACT_NAME_TO_NOT_FOUND_ERROR: {
+    [contractName: string]: ContractWrappersError;
+} = {
+    ZRX: ContractWrappersError.ZRXContractDoesNotExist,
+    EtherToken: ContractWrappersError.EtherTokenContractDoesNotExist,
+    Token: ContractWrappersError.TokenContractDoesNotExist,
+    TokenRegistry: ContractWrappersError.TokenRegistryContractDoesNotExist,
+    TokenTransferProxy: ContractWrappersError.TokenTransferProxyContractDoesNotExist,
+    Exchange: ContractWrappersError.ExchangeContractDoesNotExist,
+};
+
+export class ContractWrapper {
+    protected _web3Wrapper: Web3Wrapper;
+    protected _networkId: number;
+    private _blockAndLogStreamerIfExists?: BlockAndLogStreamer;
+    private _blockAndLogStreamIntervalIfExists?: NodeJS.Timer;
+    private _filters: { [filterToken: string]: FilterObject };
+    private _filterCallbacks: {
+        [filterToken: string]: EventCallback<ContractEventArgs>;
+    };
+    private _onLogAddedSubscriptionToken: string | undefined;
+    private _onLogRemovedSubscriptionToken: string | undefined;
+    constructor(web3Wrapper: Web3Wrapper, networkId: number) {
+        this._web3Wrapper = web3Wrapper;
+        this._networkId = networkId;
+        this._filters = {};
+        this._filterCallbacks = {};
+        this._blockAndLogStreamerIfExists = undefined;
+        this._onLogAddedSubscriptionToken = undefined;
+        this._onLogRemovedSubscriptionToken = undefined;
+    }
+    protected _unsubscribeAll(): void {
+        const filterTokens = _.keys(this._filterCallbacks);
+        _.each(filterTokens, filterToken => {
+            this._unsubscribe(filterToken);
+        });
+    }
+    protected _unsubscribe(filterToken: string, err?: Error): void {
+        if (_.isUndefined(this._filters[filterToken])) {
+            throw new Error(ContractWrappersError.SubscriptionNotFound);
+        }
+        if (!_.isUndefined(err)) {
+            const callback = this._filterCallbacks[filterToken];
+            callback(err, undefined);
+        }
+        delete this._filters[filterToken];
+        delete this._filterCallbacks[filterToken];
+        if (_.isEmpty(this._filters)) {
+            this._stopBlockAndLogStream();
+        }
+    }
+    protected _subscribe<ArgsType extends ContractEventArgs>(
+        address: string,
+        eventName: ContractEvents,
+        indexFilterValues: IndexedFilterValues,
+        abi: ContractAbi,
+        callback: EventCallback<ArgsType>,
+    ): string {
+        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi);
+        if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
+            this._startBlockAndLogStream();
+        }
+        const filterToken = filterUtils.generateUUID();
+        this._filters[filterToken] = filter;
+        this._filterCallbacks[filterToken] = callback as EventCallback<ContractEventArgs>;
+        return filterToken;
+    }
+    protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
+        address: string,
+        eventName: ContractEvents,
+        blockRange: BlockRange,
+        indexFilterValues: IndexedFilterValues,
+        abi: ContractAbi,
+    ): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
+        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, blockRange);
+        const logs = await this._web3Wrapper.getLogsAsync(filter);
+        const logsWithDecodedArguments = _.map(logs, this._tryToDecodeLogOrNoop.bind(this));
+        return logsWithDecodedArguments;
+    }
+    protected _tryToDecodeLogOrNoop<ArgsType extends ContractEventArgs>(
+        log: LogEntry,
+    ): LogWithDecodedArgs<ArgsType> | RawLog {
+        if (_.isUndefined(this._web3Wrapper.abiDecoder)) {
+            throw new Error(InternalContractWrappersError.NoAbiDecoder);
+        }
+        const logWithDecodedArgs = this._web3Wrapper.abiDecoder.tryToDecodeLogOrNoop(log);
+        return logWithDecodedArgs;
+    }
+    protected async _getContractAbiAndAddressFromArtifactsAsync(
+        artifact: Artifact,
+        addressIfExists?: string,
+    ): Promise<[ContractAbi, string]> {
+        let contractAddress: string;
+        if (_.isUndefined(addressIfExists)) {
+            if (_.isUndefined(artifact.networks[this._networkId])) {
+                throw new Error(ContractWrappersError.ContractNotDeployedOnNetwork);
+            }
+            contractAddress = artifact.networks[this._networkId].address.toLowerCase();
+        } else {
+            contractAddress = addressIfExists;
+        }
+        const doesContractExist = await this._web3Wrapper.doesContractExistAtAddressAsync(contractAddress);
+        if (!doesContractExist) {
+            throw new Error(CONTRACT_NAME_TO_NOT_FOUND_ERROR[artifact.contract_name]);
+        }
+        const abiAndAddress: [ContractAbi, string] = [artifact.abi, contractAddress];
+        return abiAndAddress;
+    }
+    protected _getContractAddress(artifact: Artifact, addressIfExists?: string): string {
+        if (_.isUndefined(addressIfExists)) {
+            const contractAddress = artifact.networks[this._networkId].address;
+            if (_.isUndefined(contractAddress)) {
+                throw new Error(ContractWrappersError.ExchangeContractDoesNotExist);
+            }
+            return contractAddress;
+        } else {
+            return addressIfExists;
+        }
+    }
+    private _onLogStateChanged<ArgsType extends ContractEventArgs>(isRemoved: boolean, log: LogEntry): void {
+        _.forEach(this._filters, (filter: FilterObject, filterToken: string) => {
+            if (filterUtils.matchesFilter(log, filter)) {
+                const decodedLog = this._tryToDecodeLogOrNoop(log) as LogWithDecodedArgs<ArgsType>;
+                const logEvent = {
+                    log: decodedLog,
+                    isRemoved,
+                };
+                this._filterCallbacks[filterToken](null, logEvent);
+            }
+        });
+    }
+    private _startBlockAndLogStream(): void {
+        if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
+            throw new Error(ContractWrappersError.SubscriptionAlreadyPresent);
+        }
+        this._blockAndLogStreamerIfExists = new BlockAndLogStreamer(
+            this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper),
+            this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper),
+        );
+        const catchAllLogFilter = {};
+        this._blockAndLogStreamerIfExists.addLogFilter(catchAllLogFilter);
+        this._blockAndLogStreamIntervalIfExists = intervalUtils.setAsyncExcludingInterval(
+            this._reconcileBlockAsync.bind(this),
+            constants.DEFAULT_BLOCK_POLLING_INTERVAL,
+            this._onReconcileBlockError.bind(this),
+        );
+        let isRemoved = false;
+        this._onLogAddedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogAdded(
+            this._onLogStateChanged.bind(this, isRemoved),
+        );
+        isRemoved = true;
+        this._onLogRemovedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogRemoved(
+            this._onLogStateChanged.bind(this, isRemoved),
+        );
+    }
+    private _onReconcileBlockError(err: Error): void {
+        const filterTokens = _.keys(this._filterCallbacks);
+        _.each(filterTokens, filterToken => {
+            this._unsubscribe(filterToken, err);
+        });
+    }
+    private _setNetworkId(networkId: number): void {
+        this._networkId = networkId;
+    }
+    private _stopBlockAndLogStream(): void {
+        if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
+            throw new Error(ContractWrappersError.SubscriptionNotFound);
+        }
+        this._blockAndLogStreamerIfExists.unsubscribeFromOnLogAdded(this._onLogAddedSubscriptionToken as string);
+        this._blockAndLogStreamerIfExists.unsubscribeFromOnLogRemoved(this._onLogRemovedSubscriptionToken as string);
+        intervalUtils.clearAsyncExcludingInterval(this._blockAndLogStreamIntervalIfExists as NodeJS.Timer);
+        delete this._blockAndLogStreamerIfExists;
+    }
+    private async _reconcileBlockAsync(): Promise<void> {
+        const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
+        // We need to coerce to Block type cause Web3.Block includes types for mempool blocks
+        if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
+            // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
+            await this._blockAndLogStreamerIfExists.reconcileNewBlock((latestBlock as any) as Block);
+        }
+    }
+}