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import { logUtils } from '@0x/utils';
import { OpCode, StructLog } from 'ethereum-types';
import * as _ from 'lodash';
import { utils } from './utils';
export interface ContractAddressToTraces {
[contractAddress: string]: StructLog[];
}
/**
* Converts linear stack trace to `ContractAddressToTraces`.
* @param structLogs stack trace
* @param startAddress initial context address
*/
export function getContractAddressToTraces(structLogs: StructLog[], startAddress: string): ContractAddressToTraces {
const contractAddressToTraces: ContractAddressToTraces = {};
let currentTraceSegment = [];
const addressStack = [startAddress];
if (_.isEmpty(structLogs)) {
return contractAddressToTraces;
}
const normalizedStructLogs = utils.normalizeStructLogs(structLogs);
// tslint:disable-next-line:prefer-for-of
for (let i = 0; i < normalizedStructLogs.length; i++) {
const structLog = normalizedStructLogs[i];
if (structLog.depth !== addressStack.length - 1) {
throw new Error("Malformed trace. Trace depth doesn't match call stack depth");
}
// After that check we have a guarantee that call stack is never empty
// If it would: callStack.length - 1 === structLog.depth === -1
// That means that we can always safely pop from it
currentTraceSegment.push(structLog);
if (utils.isCallLike(structLog.op)) {
const currentAddress = _.last(addressStack) as string;
const jumpAddressOffset = 1;
const newAddress = utils.getAddressFromStackEntry(
structLog.stack[structLog.stack.length - jumpAddressOffset - 1],
);
// Sometimes calls don't change the execution context (current address). When we do a transfer to an
// externally owned account - it does the call and immediately returns because there is no fallback
// function. We manually check if the call depth had changed to handle that case.
const nextStructLog = normalizedStructLogs[i + 1];
if (nextStructLog.depth !== structLog.depth) {
addressStack.push(newAddress);
contractAddressToTraces[currentAddress] = (contractAddressToTraces[currentAddress] || []).concat(
currentTraceSegment,
);
currentTraceSegment = [];
}
} else if (utils.isEndOpcode(structLog.op)) {
const currentAddress = addressStack.pop() as string;
contractAddressToTraces[currentAddress] = (contractAddressToTraces[currentAddress] || []).concat(
currentTraceSegment,
);
currentTraceSegment = [];
if (structLog.op === OpCode.SelfDestruct) {
// After contract execution, we look at all sub-calls to external contracts, and for each one, fetch
// the bytecode and compute the coverage for the call. If the contract is destroyed with a call
// to `selfdestruct`, we are unable to fetch it's bytecode and compute coverage.
// TODO: Refactor this logic to fetch the sub-called contract bytecode before the selfdestruct is called
// in order to handle this edge-case.
logUtils.warn(
"Detected a selfdestruct. We currently do not support that scenario. We'll just skip the trace part for a destructed contract",
);
}
} else if (structLog.op === OpCode.Create) {
// TODO: Extract the new contract address from the stack and handle that scenario
logUtils.warn(
"Detected a contract created from within another contract. We currently do not support that scenario. We'll just skip that trace",
);
return contractAddressToTraces;
} else {
if (structLog !== _.last(normalizedStructLogs)) {
const nextStructLog = normalizedStructLogs[i + 1];
if (nextStructLog.depth === structLog.depth) {
continue;
} else if (nextStructLog.depth === structLog.depth - 1) {
const currentAddress = addressStack.pop() as string;
contractAddressToTraces[currentAddress] = (contractAddressToTraces[currentAddress] || []).concat(
currentTraceSegment,
);
currentTraceSegment = [];
} else {
throw new Error('Malformed trace. Unexpected call depth change');
}
}
}
}
if (addressStack.length !== 0) {
logUtils.warn('Malformed trace. Call stack non empty at the end');
}
if (currentTraceSegment.length !== 0) {
const currentAddress = addressStack.pop() as string;
contractAddressToTraces[currentAddress] = (contractAddressToTraces[currentAddress] || []).concat(
currentTraceSegment,
);
currentTraceSegment = [];
logUtils.warn('Malformed trace. Current trace segment non empty at the end');
}
return contractAddressToTraces;
}
|
