1 files changed, 188 insertions, 0 deletions
diff --git a/packages/sol-trace-based-tools-common/src/trace_collection_subprovider.ts b/packages/sol-trace-based-tools-common/src/trace_collection_subprovider.ts
new file mode 100644
index 000000000..25e38768d
--- /dev/null
+++ b/packages/sol-trace-based-tools-common/src/trace_collection_subprovider.ts
@@ -0,0 +1,188 @@
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { Callback, ErrorCallback, NextCallback, Subprovider } from '@0x/subproviders';
+import { CallDataRPC, marshaller, Web3Wrapper } from '@0x/web3-wrapper';
+import { JSONRPCRequestPayload, Provider, TxData } from 'ethereum-types';
+import * as _ from 'lodash';
+import { Lock } from 'semaphore-async-await';
+
+import { constants } from './constants';
+import { BlockParamLiteral } from './types';
+
+interface MaybeFakeTxData extends TxData {
+    isFakeTransaction?: boolean;
+}
+
+const BLOCK_GAS_LIMIT = 6000000;
+
+export interface TraceCollectionSubproviderConfig {
+    shouldCollectTransactionTraces: boolean;
+    shouldCollectCallTraces: boolean;
+    shouldCollectGasEstimateTraces: boolean;
+}
+
+// Because there is no notion of a call trace in the Ethereum rpc - we collect them in a rather non-obvious/hacky way.
+// On each call - we create a snapshot, execute the call as a transaction, get the trace, revert the snapshot.
+// That allows us to avoid influencing test behaviour.
+
+/**
+ * This class implements the [web3-provider-engine](https://github.com/MetaMask/provider-engine) subprovider interface.
+ * It collects traces of all transactions that were sent and all calls that were executed through JSON RPC. It must
+ * be extended by implementing the _recordTxTraceAsync method which is called for every transaction.
+ */
+export abstract class TraceCollectionSubprovider extends Subprovider {
+    protected _web3Wrapper!: Web3Wrapper;
+    // Lock is used to not accept normal transactions while doing call/snapshot magic because they'll be reverted later otherwise
+    private readonly _lock = new Lock();
+    private readonly _defaultFromAddress: string;
+    private _isEnabled = true;
+    private readonly _config: TraceCollectionSubproviderConfig;
+    /**
+     * Instantiates a TraceCollectionSubprovider instance
+     * @param defaultFromAddress default from address to use when sending transactions
+     */
+    constructor(defaultFromAddress: string, config: TraceCollectionSubproviderConfig) {
+        super();
+        this._defaultFromAddress = defaultFromAddress;
+        this._config = config;
+    }
+    /**
+     * Starts trace collection
+     */
+    public start(): void {
+        this._isEnabled = true;
+    }
+    /**
+     * Stops trace collection
+     */
+    public stop(): void {
+        this._isEnabled = false;
+    }
+    /**
+     * This method conforms to the web3-provider-engine interface.
+     * It is called internally by the ProviderEngine when it is this subproviders
+     * turn to handle a JSON RPC request.
+     * @param payload JSON RPC payload
+     * @param next Callback to call if this subprovider decides not to handle the request
+     * @param _end Callback to call if subprovider handled the request and wants to pass back the request.
+     */
+    // tslint:disable-next-line:prefer-function-over-method async-suffix
+    public async handleRequest(payload: JSONRPCRequestPayload, next: NextCallback, _end: ErrorCallback): Promise<void> {
+        if (this._isEnabled) {
+            switch (payload.method) {
+                case 'eth_sendTransaction':
+                    if (!this._config.shouldCollectTransactionTraces) {
+                        next();
+                    } else {
+                        const txData = payload.params[0];
+                        next(this._onTransactionSentAsync.bind(this, txData));
+                    }
+                    return;
+
+                case 'eth_call':
+                    if (!this._config.shouldCollectCallTraces) {
+                        next();
+                    } else {
+                        const callData = payload.params[0];
+                        next(this._onCallOrGasEstimateExecutedAsync.bind(this, callData));
+                    }
+                    return;
+
+                case 'eth_estimateGas':
+                    if (!this._config.shouldCollectGasEstimateTraces) {
+                        next();
+                    } else {
+                        const estimateGasData = payload.params[0];
+                        next(this._onCallOrGasEstimateExecutedAsync.bind(this, estimateGasData));
+                    }
+                    return;
+
+                default:
+                    next();
+                    return;
+            }
+        } else {
+            next();
+            return;
+        }
+    }
+    /**
+     * Set's the subprovider's engine to the ProviderEngine it is added to.
+     * This is only called within the ProviderEngine source code, do not call
+     * directly.
+     * @param engine The ProviderEngine this subprovider is added to
+     */
+    public setEngine(engine: Provider): void {
+        super.setEngine(engine);
+        this._web3Wrapper = new Web3Wrapper(engine);
+    }
+    protected abstract async _recordTxTraceAsync(
+        address: string,
+        data: string | undefined,
+        txHash: string,
+    ): Promise<void>;
+    private async _onTransactionSentAsync(
+        txData: MaybeFakeTxData,
+        err: Error | null,
+        txHash: string | undefined,
+        cb: Callback,
+    ): Promise<void> {
+        if (!txData.isFakeTransaction) {
+            // This transaction is a usual transaction. Not a call executed as one.
+            // And we don't want it to be executed within a snapshotting period
+            await this._lock.acquire();
+        }
+        const NULL_ADDRESS = '0x0';
+        if (_.isNull(err)) {
+            const toAddress =
+                _.isUndefined(txData.to) || txData.to === NULL_ADDRESS ? constants.NEW_CONTRACT : txData.to;
+            await this._recordTxTraceAsync(toAddress, txData.data, txHash as string);
+        } else {
+            const latestBlock = await this._web3Wrapper.getBlockWithTransactionDataAsync(BlockParamLiteral.Latest);
+            const transactions = latestBlock.transactions;
+            for (const transaction of transactions) {
+                const toAddress =
+                    _.isUndefined(txData.to) || txData.to === NULL_ADDRESS ? constants.NEW_CONTRACT : txData.to;
+                await this._recordTxTraceAsync(toAddress, transaction.input, transaction.hash);
+            }
+        }
+        if (!txData.isFakeTransaction) {
+            // This transaction is a usual transaction. Not a call executed as one.
+            // And we don't want it to be executed within a snapshotting period
+            this._lock.release();
+        }
+        cb();
+    }
+    private async _onCallOrGasEstimateExecutedAsync(
+        callData: Partial<CallDataRPC>,
+        _err: Error | null,
+        _callResult: string,
+        cb: Callback,
+    ): Promise<void> {
+        await this._recordCallOrGasEstimateTraceAsync(callData);
+        cb();
+    }
+    private async _recordCallOrGasEstimateTraceAsync(callData: Partial<CallDataRPC>): Promise<void> {
+        // We don't want other transactions to be exeucted during snashotting period, that's why we lock the
+        // transaction execution for all transactions except our fake ones.
+        await this._lock.acquire();
+        const blockchainLifecycle = new BlockchainLifecycle(this._web3Wrapper);
+        await blockchainLifecycle.startAsync();
+        const fakeTxData = {
+            gas: BLOCK_GAS_LIMIT.toString(16), // tslint:disable-line:custom-no-magic-numbers
+            isFakeTransaction: true, // This transaction (and only it) is allowed to come through when the lock is locked
+            ...callData,
+            from: callData.from || this._defaultFromAddress,
+        };
+        try {
+            const txData = marshaller.unmarshalTxData(fakeTxData);
+            const txHash = await this._web3Wrapper.sendTransactionAsync(txData);
+            await this._web3Wrapper.awaitTransactionMinedAsync(txHash, 0);
+        } catch (err) {
+            // TODO(logvinov) Check that transaction failed and not some other exception
+            // Even if this transaction failed - we've already recorded it's trace.
+            _.noop();
+        }
+        await blockchainLifecycle.revertAsync();
+        this._lock.release();
+    }
+}