2 files changed, 120 insertions, 0 deletions
diff --git a/lib/internal/coverage-gen/with_instrumentation.js b/lib/internal/coverage-gen/with_instrumentation.js
new file mode 100644
index 0000000000..711a3c3f12
--- /dev/null
+++ b/lib/internal/coverage-gen/with_instrumentation.js
@@ -0,0 +1,36 @@
+'use strict';
+
+// This file contains hooks for nyc instrumented lib/ files to collect
+// JS coverage for core.
+// See `make coverage-build`.
+function writeCoverage() {
+  if (!global.__coverage__) {
+    return;
+  }
+
+  const path = require('path');
+  const { mkdirSync, writeFileSync } = require('fs');
+
+  const dirname = path.join(path.dirname(process.execPath), '.coverage');
+  const filename = `coverage-${process.pid}-${Date.now()}.json`;
+  try {
+    mkdirSync(dirname);
+  } catch (err) {
+    if (err.code !== 'EEXIST') {
+      console.error(err);
+      return;
+    }
+  }
+
+  const target = path.join(dirname, filename);
+  const coverageInfo = JSON.stringify(global.__coverage__);
+  try {
+    writeFileSync(target, coverageInfo);
+  } catch (err) {
+    console.error(err);
+  }
+}
+
+module.exports = {
+  writeCoverage
+};
diff --git a/lib/internal/coverage-gen/with_profiler.js b/lib/internal/coverage-gen/with_profiler.js
new file mode 100644
index 0000000000..6b17073939
--- /dev/null
+++ b/lib/internal/coverage-gen/with_profiler.js
@@ -0,0 +1,84 @@
+'use strict';
+
+// Implements coverage collection exposed by the `NODE_V8_COVERAGE`
+// environment variable which can also be used in the user land.
+
+let coverageConnection = null;
+let coverageDirectory;
+
+function writeCoverage() {
+  if (!coverageConnection && coverageDirectory) {
+    return;
+  }
+
+  const { join } = require('path');
+  const { mkdirSync, writeFileSync } = require('fs');
+  const { threadId } = require('internal/worker');
+
+  const filename = `coverage-${process.pid}-${Date.now()}-${threadId}.json`;
+  try {
+    mkdirSync(coverageDirectory, { recursive: true });
+  } catch (err) {
+    if (err.code !== 'EEXIST') {
+      console.error(err);
+      return;
+    }
+  }
+
+  const target = join(coverageDirectory, filename);
+  try {
+    disableAllAsyncHooks();
+    let msg;
+    coverageConnection._coverageCallback = function(_msg) {
+      msg = _msg;
+    };
+    coverageConnection.dispatch(JSON.stringify({
+      id: 3,
+      method: 'Profiler.takePreciseCoverage'
+    }));
+    const coverageInfo = JSON.parse(msg).result;
+    writeFileSync(target, JSON.stringify(coverageInfo));
+  } catch (err) {
+    console.error(err);
+  } finally {
+    coverageConnection.disconnect();
+    coverageConnection = null;
+  }
+}
+
+function disableAllAsyncHooks() {
+  const { getHookArrays } = require('internal/async_hooks');
+  const [hooks_array] = getHookArrays();
+  hooks_array.forEach((hook) => { hook.disable(); });
+}
+
+function startCoverageCollection() {
+  const { Connection } = internalBinding('inspector');
+  coverageConnection = new Connection((res) => {
+    if (coverageConnection._coverageCallback) {
+      coverageConnection._coverageCallback(res);
+    }
+  });
+  coverageConnection.dispatch(JSON.stringify({
+    id: 1,
+    method: 'Profiler.enable'
+  }));
+  coverageConnection.dispatch(JSON.stringify({
+    id: 2,
+    method: 'Profiler.startPreciseCoverage',
+    params: {
+      callCount: true,
+      detailed: true
+    }
+  }));
+}
+
+function setCoverageDirectory(dir) {
+  coverageDirectory = dir;
+}
+
+module.exports = {
+  startCoverageCollection,
+  writeCoverage,
+  setCoverageDirectory
+};