1 files changed, 100 insertions, 0 deletions
diff --git a/packages/sol-cov/src/trace.ts b/packages/sol-cov/src/trace.ts
new file mode 100644
index 000000000..6bc28989d
--- /dev/null
+++ b/packages/sol-cov/src/trace.ts
@@ -0,0 +1,100 @@
+import { StructLog, TransactionTrace } from '@0xproject/types';
+import { BigNumber } from '@0xproject/utils';
+import { addHexPrefix, stripHexPrefix } from 'ethereumjs-util';
+import * as fs from 'fs';
+import * as _ from 'lodash';
+
+export interface TraceByContractAddress {
+    [contractAddress: string]: StructLog[];
+}
+function padZeros(address: string) {
+    return addHexPrefix(_.padStart(stripHexPrefix(address), 40, '0'));
+}
+
+export function getTracesByContractAddress(structLogs: StructLog[], startAddress: string): TraceByContractAddress {
+    const traceByContractAddress: TraceByContractAddress = {};
+    let currentTraceSegment = [];
+    const callStack = [startAddress];
+    // tslint:disable-next-line: prefer-for-of
+    for (let i = 0; i < structLogs.length; ++i) {
+        const structLog = structLogs[i];
+        if (structLog.depth !== callStack.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 (structLog.op === 'DELEGATECALL') {
+            const currentAddress = _.last(callStack) as string;
+            const jumpAddressOffset = 4;
+            const newAddress = padZeros(new BigNumber(addHexPrefix(structLog.stack[jumpAddressOffset])).toString(16));
+            callStack.push(newAddress);
+            traceByContractAddress[currentAddress] = (traceByContractAddress[currentAddress] || []).concat(
+                currentTraceSegment,
+            );
+            currentTraceSegment = [];
+        } else if (structLog.op === 'RETURN') {
+            const currentAddress = callStack.pop() as string;
+            traceByContractAddress[currentAddress] = (traceByContractAddress[currentAddress] || []).concat(
+                currentTraceSegment,
+            );
+            currentTraceSegment = [];
+        } else if (structLog.op === 'STOP') {
+            const currentAddress = callStack.pop() as string;
+            traceByContractAddress[currentAddress] = (traceByContractAddress[currentAddress] || []).concat(
+                currentTraceSegment,
+            );
+            currentTraceSegment = [];
+            if (i !== structLogs.length - 1) {
+                throw new Error('Malformed trace. STOP is not the last opcode executed');
+            }
+        } else if (structLog.op === 'CREATE') {
+            console.warn(
+                "Detected a contract created from within another contract. Sol-cov currently doesn't support that scenario. We'll just skip that trace",
+            );
+            return traceByContractAddress;
+        } else if (structLog.op === 'CALL') {
+            const currentAddress = _.last(callStack) as string;
+            const jumpAddressOffset = 2;
+            const newAddress = padZeros(new BigNumber(addHexPrefix(structLog.stack[jumpAddressOffset])).toString(16));
+            callStack.push(newAddress);
+            traceByContractAddress[currentAddress] = (traceByContractAddress[currentAddress] || []).concat(
+                currentTraceSegment,
+            );
+            currentTraceSegment = [];
+        } else if (structLog.op === 'CALLCODE') {
+            throw new Error('CALLCODE opcode unsupported by coverage');
+        } else if (structLog.op === 'STATICCALL') {
+            throw new Error('STATICCALL opcode unsupported by coverage');
+        } else if (structLog.op === 'REVERT') {
+            const currentAddress = callStack.pop() as string;
+            traceByContractAddress[currentAddress] = (traceByContractAddress[currentAddress] || []).concat(
+                currentTraceSegment,
+            );
+            currentTraceSegment = [];
+            if (i !== structLogs.length - 1) {
+                throw new Error('Malformed trace. REVERT is not the last opcode executed');
+            }
+        } else if (structLog.op === 'INVALID') {
+            const currentAddress = callStack.pop() as string;
+            traceByContractAddress[currentAddress] = (traceByContractAddress[currentAddress] || []).concat(
+                currentTraceSegment,
+            );
+            currentTraceSegment = [];
+            if (i !== structLogs.length - 1) {
+                throw new Error('Malformed trace. INVALID is not the last opcode executed');
+            }
+        } else if (structLog.op === 'SELFDESTRUCT') {
+            throw new Error('SELFDESTRUCT opcode unsupported by coverage');
+        }
+    }
+    if (callStack.length !== 0) {
+        throw new Error('Malformed trace. Call stack non empty at the end');
+    }
+    if (currentTraceSegment.length !== 0) {
+        throw new Error('Malformed trace. currentTraceSegment non empty at the end');
+    }
+    return traceByContractAddress;
+}