1 files changed, 146 insertions, 0 deletions
diff --git a/packages/sol-coverage/src/coverage_subprovider.ts b/packages/sol-coverage/src/coverage_subprovider.ts
new file mode 100644
index 000000000..e6b546c4a
--- /dev/null
+++ b/packages/sol-coverage/src/coverage_subprovider.ts
@@ -0,0 +1,146 @@
+import {
+    AbstractArtifactAdapter,
+    BranchCoverage,
+    collectCoverageEntries,
+    ContractData,
+    Coverage,
+    FunctionCoverage,
+    FunctionDescription,
+    SingleFileSubtraceHandler,
+    SourceRange,
+    StatementCoverage,
+    StatementDescription,
+    Subtrace,
+    TraceCollector,
+    TraceInfo,
+    TraceInfoSubprovider,
+    utils,
+} from '@0x/sol-tracing-utils';
+import * as _ from 'lodash';
+
+/**
+ * This class implements the [web3-provider-engine](https://github.com/MetaMask/provider-engine) subprovider interface.
+ * It's used to compute your code coverage while running solidity tests.
+ */
+export class CoverageSubprovider extends TraceInfoSubprovider {
+    private readonly _coverageCollector: TraceCollector;
+    /**
+     * Instantiates a CoverageSubprovider instance
+     * @param artifactAdapter Adapter for used artifacts format (0x, truffle, giveth, etc.)
+     * @param defaultFromAddress default from address to use when sending transactions
+     * @param isVerbose If true, we will log any unknown transactions. Otherwise we will ignore them
+     */
+    constructor(artifactAdapter: AbstractArtifactAdapter, defaultFromAddress: string, isVerbose: boolean = true) {
+        const traceCollectionSubproviderConfig = {
+            shouldCollectTransactionTraces: true,
+            shouldCollectGasEstimateTraces: true,
+            shouldCollectCallTraces: true,
+        };
+        super(defaultFromAddress, traceCollectionSubproviderConfig);
+        this._coverageCollector = new TraceCollector(artifactAdapter, isVerbose, coverageHandler);
+    }
+    protected async _handleTraceInfoAsync(traceInfo: TraceInfo): Promise<void> {
+        await this._coverageCollector.computeSingleTraceCoverageAsync(traceInfo);
+    }
+    /**
+     * Write the test coverage results to a file in Istanbul format.
+     */
+    public async writeCoverageAsync(): Promise<void> {
+        await this._coverageCollector.writeOutputAsync();
+    }
+}
+
+/**
+ * Computed partial coverage for a single file & subtrace.
+ * @param contractData      Contract metadata (source, srcMap, bytecode)
+ * @param subtrace          A subset of a transcation/call trace that was executed within that contract
+ * @param pcToSourceRange   A mapping from program counters to source ranges
+ * @param fileIndex         Index of a file to compute coverage for
+ * @return Partial istanbul coverage for that file & subtrace
+ */
+export const coverageHandler: SingleFileSubtraceHandler = (
+    contractData: ContractData,
+    subtrace: Subtrace,
+    pcToSourceRange: { [programCounter: number]: SourceRange },
+    fileIndex: number,
+): Coverage => {
+    const absoluteFileName = contractData.sources[fileIndex];
+    const coverageEntriesDescription = collectCoverageEntries(contractData.sourceCodes[fileIndex]);
+
+    // if the source wasn't provided for the fileIndex, we can't cover the file
+    if (_.isUndefined(coverageEntriesDescription)) {
+        return {};
+    }
+
+    let sourceRanges = _.map(subtrace, structLog => pcToSourceRange[structLog.pc]);
+    sourceRanges = _.compact(sourceRanges); // Some PC's don't map to a source range and we just ignore them.
+    // By default lodash does a shallow object comparasion. We JSON.stringify them and compare as strings.
+    sourceRanges = _.uniqBy(sourceRanges, s => JSON.stringify(s)); // We don't care if one PC was covered multiple times within a single transaction
+    sourceRanges = _.filter(sourceRanges, sourceRange => sourceRange.fileName === absoluteFileName);
+    const branchCoverage: BranchCoverage = {};
+    const branchIds = _.keys(coverageEntriesDescription.branchMap);
+    for (const branchId of branchIds) {
+        const branchDescription = coverageEntriesDescription.branchMap[branchId];
+        const isBranchCoveredByBranchIndex = _.map(branchDescription.locations, location => {
+            const isBranchCovered = _.some(sourceRanges, range => utils.isRangeInside(range.location, location));
+            const timesBranchCovered = Number(isBranchCovered);
+            return timesBranchCovered;
+        });
+        branchCoverage[branchId] = isBranchCoveredByBranchIndex;
+    }
+    const statementCoverage: StatementCoverage = {};
+    const statementIds = _.keys(coverageEntriesDescription.statementMap);
+    for (const statementId of statementIds) {
+        const statementDescription = coverageEntriesDescription.statementMap[statementId];
+        const isStatementCovered = _.some(sourceRanges, range =>
+            utils.isRangeInside(range.location, statementDescription),
+        );
+        const timesStatementCovered = Number(isStatementCovered);
+        statementCoverage[statementId] = timesStatementCovered;
+    }
+    const functionCoverage: FunctionCoverage = {};
+    const functionIds = _.keys(coverageEntriesDescription.fnMap);
+    for (const fnId of functionIds) {
+        const functionDescription = coverageEntriesDescription.fnMap[fnId];
+        const isFunctionCovered = _.some(sourceRanges, range =>
+            utils.isRangeInside(range.location, functionDescription.loc),
+        );
+        const timesFunctionCovered = Number(isFunctionCovered);
+        functionCoverage[fnId] = timesFunctionCovered;
+    }
+    // HACK: Solidity doesn't emit any opcodes that map back to modifiers with no args, that's why we map back to the
+    // function range and check if there is any covered statement within that range.
+    for (const modifierStatementId of coverageEntriesDescription.modifiersStatementIds) {
+        if (statementCoverage[modifierStatementId]) {
+            // Already detected as covered
+            continue;
+        }
+        const modifierDescription = coverageEntriesDescription.statementMap[modifierStatementId];
+        const enclosingFunction = _.find(coverageEntriesDescription.fnMap, functionDescription =>
+            utils.isRangeInside(modifierDescription, functionDescription.loc),
+        ) as FunctionDescription;
+        const isModifierCovered = _.some(
+            coverageEntriesDescription.statementMap,
+            (statementDescription: StatementDescription, statementId: number) => {
+                const isInsideTheModifierEnclosingFunction = utils.isRangeInside(
+                    statementDescription,
+                    enclosingFunction.loc,
+                );
+                const isCovered = statementCoverage[statementId];
+                return isInsideTheModifierEnclosingFunction && isCovered;
+            },
+        );
+        const timesModifierCovered = Number(isModifierCovered);
+        statementCoverage[modifierStatementId] = timesModifierCovered;
+    }
+    const partialCoverage = {
+        [absoluteFileName]: {
+            ...coverageEntriesDescription,
+            path: absoluteFileName,
+            f: functionCoverage,
+            s: statementCoverage,
+            b: branchCoverage,
+        },
+    };
+    return partialCoverage;
+};