From c4ee2d73865a1444c079b9e2836b7630a0adf03e Mon Sep 17 00:00:00 2001
From: Fabio Berger <me@fabioberger.com>
Date: Sun, 12 Nov 2017 22:17:18 -0500
Subject: Switch over to Lerna + Yarn Workspaces setup for a mono-repo approach

---
 .../src/contract_wrappers/contract_wrapper.ts      | 152 +++++++++++++++++++++
 1 file changed, 152 insertions(+)
 create mode 100644 packages/0x.js/src/contract_wrappers/contract_wrapper.ts

(limited to 'packages/0x.js/src/contract_wrappers/contract_wrapper.ts')

diff --git a/packages/0x.js/src/contract_wrappers/contract_wrapper.ts b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
new file mode 100644
index 000000000..7997b1647
--- /dev/null
+++ b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
@@ -0,0 +1,152 @@
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+import {BlockAndLogStreamer, Block} from 'ethereumjs-blockstream';
+import {Web3Wrapper} from '../web3_wrapper';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {
+    ZeroExError,
+    InternalZeroExError,
+    Artifact,
+    LogWithDecodedArgs,
+    RawLog,
+    ContractEvents,
+    SubscriptionOpts,
+    IndexedFilterValues,
+    EventCallback,
+    BlockParamLiteral,
+    ContractEventArgs,
+} from '../types';
+import {constants} from '../utils/constants';
+import {intervalUtils} from '../utils/interval_utils';
+import {filterUtils} from '../utils/filter_utils';
+
+export class ContractWrapper {
+    protected _web3Wrapper: Web3Wrapper;
+    private _abiDecoder?: AbiDecoder;
+    private _blockAndLogStreamer: BlockAndLogStreamer|undefined;
+    private _blockAndLogStreamInterval: NodeJS.Timer;
+    private _filters: {[filterToken: string]: Web3.FilterObject};
+    private _filterCallbacks: {[filterToken: string]: EventCallback<ContractEventArgs>};
+    private _onLogAddedSubscriptionToken: string|undefined;
+    private _onLogRemovedSubscriptionToken: string|undefined;
+    constructor(web3Wrapper: Web3Wrapper, abiDecoder?: AbiDecoder) {
+        this._web3Wrapper = web3Wrapper;
+        this._abiDecoder = abiDecoder;
+        this._filters = {};
+        this._filterCallbacks = {};
+        this._blockAndLogStreamer = undefined;
+        this._onLogAddedSubscriptionToken = undefined;
+        this._onLogRemovedSubscriptionToken = undefined;
+    }
+    /**
+     * Cancels all existing subscriptions
+     */
+    public 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(ZeroExError.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: Web3.ContractAbi,
+        callback: EventCallback<ArgsType>): string {
+        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi);
+        if (_.isUndefined(this._blockAndLogStreamer)) {
+            this._startBlockAndLogStream();
+        }
+        const filterToken = filterUtils.generateUUID();
+        this._filters[filterToken] = filter;
+        this._filterCallbacks[filterToken] = callback;
+        return filterToken;
+    }
+    protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
+        address: string, eventName: ContractEvents, subscriptionOpts: SubscriptionOpts,
+        indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
+        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, subscriptionOpts);
+        const logs = await this._web3Wrapper.getLogsAsync(filter);
+        const logsWithDecodedArguments = _.map(logs, this._tryToDecodeLogOrNoop.bind(this));
+        return logsWithDecodedArguments;
+    }
+    protected _tryToDecodeLogOrNoop<ArgsType extends ContractEventArgs>(
+        log: Web3.LogEntry): LogWithDecodedArgs<ArgsType>|RawLog {
+        if (_.isUndefined(this._abiDecoder)) {
+            throw new Error(InternalZeroExError.NoAbiDecoder);
+        }
+        const logWithDecodedArgs = this._abiDecoder.tryToDecodeLogOrNoop(log);
+        return logWithDecodedArgs;
+    }
+    protected async _instantiateContractIfExistsAsync<ContractType extends Web3.ContractInstance>(
+        artifact: Artifact, addressIfExists?: string): Promise<ContractType> {
+        const contractInstance =
+            await this._web3Wrapper.getContractInstanceFromArtifactAsync<ContractType>(artifact, addressIfExists);
+        return contractInstance;
+    }
+    private _onLogStateChanged<ArgsType extends ContractEventArgs>(removed: boolean, log: Web3.LogEntry): void {
+        _.forEach(this._filters, (filter: Web3.FilterObject, filterToken: string) => {
+            if (filterUtils.matchesFilter(log, filter)) {
+                const decodedLog = this._tryToDecodeLogOrNoop(log) as LogWithDecodedArgs<ArgsType>;
+                const logEvent = {
+                    ...decodedLog,
+                    removed,
+                };
+                this._filterCallbacks[filterToken](null, logEvent);
+            }
+        });
+    }
+    private _startBlockAndLogStream(): void {
+        this._blockAndLogStreamer = new BlockAndLogStreamer(
+            this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper),
+            this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper),
+        );
+        const catchAllLogFilter = {};
+        this._blockAndLogStreamer.addLogFilter(catchAllLogFilter);
+        this._blockAndLogStreamInterval = intervalUtils.setAsyncExcludingInterval(
+            this._reconcileBlockAsync.bind(this), constants.DEFAULT_BLOCK_POLLING_INTERVAL,
+        );
+        let removed = false;
+        this._onLogAddedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogAdded(
+            this._onLogStateChanged.bind(this, removed),
+        );
+        removed = true;
+        this._onLogRemovedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogRemoved(
+            this._onLogStateChanged.bind(this, removed),
+        );
+    }
+    private _stopBlockAndLogStream(): void {
+        (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogAdded(
+            this._onLogAddedSubscriptionToken as string);
+        (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogRemoved(
+            this._onLogRemovedSubscriptionToken as string);
+        intervalUtils.clearAsyncExcludingInterval(this._blockAndLogStreamInterval);
+        delete this._blockAndLogStreamer;
+    }
+    private async _reconcileBlockAsync(): Promise<void> {
+        try {
+            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._blockAndLogStreamer)) {
+                // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
+                this._blockAndLogStreamer.reconcileNewBlock(latestBlock as any as Block);
+            }
+        } catch (err) {
+            const filterTokens = _.keys(this._filterCallbacks);
+            _.each(filterTokens, filterToken => {
+                this._unsubscribe(filterToken, err);
+            });
+        }
+    }
+}
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