import { Callback, NextCallback, Subprovider } from '@0xproject/subproviders'; import { promisify } from '@0xproject/utils'; import * as _ from 'lodash'; import { Lock } from 'semaphore-async-await'; import * as Web3 from 'web3'; import { constants } from './constants'; import { CoverageManager } from './coverage_manager'; import { TraceInfoExistingContract, TraceInfoNewContract } from './types'; interface MaybeFakeTxData extends Web3.TxData { isFakeTransaction?: boolean; } /* * This class implements the web3-provider-engine subprovider interface and collects traces of all transactions that were sent and all calls that were executed. * Because there is no notion of call trace in the rpc - we collect them in 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 not influence the test behaviour. * Source: https://github.com/MetaMask/provider-engine/blob/master/subproviders/subprovider.js */ export class CoverageSubprovider extends Subprovider { // Lock is used to not accept normal transactions while doing call/snapshot magic because they'll be reverted later otherwise private _lock: Lock; private _coverageManager: CoverageManager; private _defaultFromAddress: string; constructor(artifactsPath: string, sourcesPath: string, networkId: number, defaultFromAddress: string) { super(); this._lock = new Lock(); this._defaultFromAddress = defaultFromAddress; this._coverageManager = new CoverageManager( artifactsPath, sourcesPath, networkId, this._getContractCodeAsync.bind(this), ); } public handleRequest( payload: Web3.JSONRPCRequestPayload, next: NextCallback, end: (err: Error | null, result: any) => void, ) { switch (payload.method) { case 'eth_sendTransaction': const txData = payload.params[0]; next(this._onTransactionSentAsync.bind(this, txData)); return; case 'eth_call': const callData = payload.params[0]; const blockNumber = payload.params[1]; next(this._onCallExecutedAsync.bind(this, callData, blockNumber)); return; default: next(); return; } } public async writeCoverageAsync(): Promise { await this._coverageManager.writeCoverageAsync(); } private async _onTransactionSentAsync( txData: MaybeFakeTxData, err: Error | null, txHash: string | undefined, cb: Callback, ): Promise { if (!txData.isFakeTransaction) { // This transaction is a usual ttransaction. Not a call executed as one. // And we don't want it to be executed within a snapshotting period await this._lock.acquire(); } if (_.isNull(err)) { const toAddress = _.isUndefined(txData.to) || txData.to === '0x0' ? constants.NEW_CONTRACT : txData.to; await this._recordTxTraceAsync(toAddress, txData.data, txHash as string); } else { const payload = { method: 'eth_getBlockByNumber', params: ['latest', true], }; const jsonRPCResponsePayload = await this.emitPayloadAsync(payload); const transactions = jsonRPCResponsePayload.result.transactions; for (const transaction of transactions) { const toAddress = _.isUndefined(txData.to) || txData.to === '0x0' ? constants.NEW_CONTRACT : txData.to; await this._recordTxTraceAsync(toAddress, transaction.data, transaction.hash); } } if (!txData.isFakeTransaction) { // This transaction is a usual ttransaction. 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 _onCallExecutedAsync( callData: Partial, blockNumber: Web3.BlockParam, err: Error | null, callResult: string, cb: Callback, ): Promise { await this._recordCallTraceAsync(callData, blockNumber); cb(); } private async _recordTxTraceAsync(address: string, data: string | undefined, txHash: string): Promise { let payload = { method: 'debug_traceTransaction', params: [txHash, { disableMemory: true, disableStack: true, disableStorage: true }], // TODO For now testrpc just ignores those parameters https://github.com/trufflesuite/ganache-cli/issues/489 }; const jsonRPCResponsePayload = await this.emitPayloadAsync(payload); const trace: Web3.TransactionTrace = jsonRPCResponsePayload.result; const coveredPcs = _.map(trace.structLogs, log => log.pc); if (address === constants.NEW_CONTRACT) { const traceInfo: TraceInfoNewContract = { coveredPcs, txHash, address: address as 'NEW_CONTRACT', bytecode: data as string, }; this._coverageManager.appendTraceInfo(traceInfo); } else { payload = { method: 'eth_getCode', params: [address, 'latest'] }; const runtimeBytecode = (await this.emitPayloadAsync(payload)).result; const traceInfo: TraceInfoExistingContract = { coveredPcs, txHash, address, runtimeBytecode, }; this._coverageManager.appendTraceInfo(traceInfo); } } private async _recordCallTraceAsync(callData: Partial, blockNumber: Web3.BlockParam): Promise { // 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 snapshotId = Number((await this.emitPayloadAsync({ method: 'evm_snapshot' })).result); const fakeTxData: MaybeFakeTxData = { isFakeTransaction: true, // This transaction (and only it) is allowed to come through when the lock is locked ...callData, from: callData.from || this._defaultFromAddress, }; try { await this.emitPayloadAsync({ method: 'eth_sendTransaction', params: [fakeTxData], }); } catch (err) { // Even if this transaction failed - we've already recorded it's trace. } const jsonRPCResponse = await this.emitPayloadAsync({ method: 'evm_revert', params: [snapshotId] }); this._lock.release(); const didRevert = jsonRPCResponse.result; if (!didRevert) { throw new Error('Failed to revert the snapshot'); } } private async _getContractCodeAsync(address: string): Promise { const payload = { method: 'eth_getCode', params: [address, 'latest'], }; const jsonRPCResponsePayload = await this.emitPayloadAsync(payload); const contractCode: string = jsonRPCResponsePayload.result; return contractCode; } }