core(traces): move findTracingStartedEvt to tracingProcessor

And add support of new traces to scripts/minify-trace.js
GoogleChrome · Jun 5, 2018 · 4826a77 · 4826a77
1 parent df631a0
commit 4826a77
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Showing 3 changed files with 43 additions and 28 deletions.
diff --git a/lighthouse-core/gather/computed/trace-of-tab.js b/lighthouse-core/gather/computed/trace-of-tab.js
@@ -18,6 +18,7 @@
 
 const ComputedArtifact = require('./computed-artifact');
 const log = require('lighthouse-logger');
+const TracingProcessor = require('../../lib/traces/tracing-processor');
 const LHError = require('../../lib/errors');
 const Sentry = require('../../lib/sentry');
 
@@ -51,31 +52,8 @@ class TraceOfTab extends ComputedArtifact {
       // @ts-ignore - stableSort added to Array by WebInspector.
       .stableSort((event0, event1) => event0.ts - event1.ts);
 
-    // Find out the inspected page frame.
-    /** @type {LH.TraceEvent|undefined} */
-    let startedInPageEvt;
-    const startedInBrowserEvt = keyEvents.find(e => e.name === 'TracingStartedInBrowser');
-    if (startedInBrowserEvt && startedInBrowserEvt.args.data &&
-        startedInBrowserEvt.args.data.frames) {
-      const mainFrame = startedInBrowserEvt.args.data.frames.find(frame => !frame.parent);
-      const pid = mainFrame && mainFrame.processId;
-      const threadNameEvt = keyEvents.find(e => e.pid === pid && e.ph === 'M' &&
-        e.cat === '__metadata' && e.name === 'thread_name' && e.args.name === 'CrRendererMain');
-      startedInPageEvt = mainFrame && threadNameEvt ?
-        Object.assign({}, startedInBrowserEvt, {
-          pid, tid: threadNameEvt.tid, name: 'TracingStartedInPage',
-          args: {data: {page: mainFrame.frame}}}) :
-        undefined;
-    }
-    // Support legacy browser versions that do not emit TracingStartedInBrowser event.
-    if (!startedInPageEvt) {
-      // The first TracingStartedInPage in the trace is definitely our renderer thread of interest
-      // Beware: the tracingStartedInPage event can appear slightly after a navigationStart
-      startedInPageEvt = keyEvents.find(e => e.name === 'TracingStartedInPage');
-    }
-    if (!startedInPageEvt) throw new LHError(LHError.errors.NO_TRACING_STARTED);
-    // @ts-ignore - property chain exists for 'TracingStartedInPage' event.
-    const frameId = startedInPageEvt.args.data.page;
+    // Find the inspected frame
+    const {startedInPageEvt, frameId} = TracingProcessor.findTracingStartedEvt(keyEvents);
 
     // Filter to just events matching the frame ID for sanity
     const frameEvents = keyEvents.filter(e => e.args.frame === frameId);

diff --git a/lighthouse-core/lib/traces/tracing-processor.js b/lighthouse-core/lib/traces/tracing-processor.js
@@ -10,6 +10,7 @@
 const BASE_RESPONSE_LATENCY = 16;
 const SCHEDULABLE_TASK_TITLE = 'TaskQueueManager::ProcessTaskFromWorkQueue';
 const SCHEDULABLE_TASK_TITLE_ALT = 'ThreadControllerImpl::DoWork';
+const LHError = require('../errors');
 
 class TraceProcessor {
   /**
@@ -179,6 +180,43 @@ class TraceProcessor {
     return topLevelEvents;
   }
 
+  /**
+   * @param {LH.TraceEvent[]} events
+   * @return {{startedInPageEvt: LH.TraceEvent, frameId: string}}
+   */
+  static findTracingStartedEvt(events) {
+    /** @type {LH.TraceEvent|undefined} */
+    let startedInPageEvt;
+
+    // Prefer the newer TracingStartedInBrowser event first, if it exists
+    const startedInBrowserEvt = events.find(e => e.name === 'TracingStartedInBrowser');
+    if (startedInBrowserEvt && startedInBrowserEvt.args.data &&
+        startedInBrowserEvt.args.data.frames) {
+      const mainFrame = startedInBrowserEvt.args.data.frames.find(frame => !frame.parent);
+      const pid = mainFrame && mainFrame.processId;
+      const threadNameEvt = events.find(e => e.pid === pid && e.ph === 'M' &&
+        e.cat === '__metadata' && e.name === 'thread_name' && e.args.name === 'CrRendererMain');
+      startedInPageEvt = mainFrame && threadNameEvt ?
+        Object.assign({}, startedInBrowserEvt, {
+          pid, tid: threadNameEvt.tid, name: 'TracingStartedInPage',
+          args: {data: {page: mainFrame.frame}}}) :
+        undefined;
+    }
+
+    // Support legacy browser versions that do not emit TracingStartedInBrowser event.
+    if (!startedInPageEvt) {
+      // The first TracingStartedInPage in the trace is definitely our renderer thread of interest
+      // Beware: the tracingStartedInPage event can appear slightly after a navigationStart
+      startedInPageEvt = events.find(e => e.name === 'TracingStartedInPage');
+    }
+
+    if (!startedInPageEvt) throw new LHError(LHError.errors.NO_TRACING_STARTED);
+
+    // @ts-ignore - property chain exists for 'TracingStartedInPage' event.
+    const frameId = /** @type {string} */ (startedInPageEvt.args.data.page);
+    return {startedInPageEvt, frameId};
+  }
+
   /**
    * @param {LH.TraceEvent} evt
    * @return {boolean}

diff --git a/lighthouse-core/scripts/lantern/minify-trace.js b/lighthouse-core/scripts/lantern/minify-trace.js
@@ -18,6 +18,7 @@
 
 const fs = require('fs');
 const path = require('path');
+const TracingProcessor = require('../../lib/traces/tracing-processor');
 
 if (process.argv.length !== 4) {
   console.error('Usage $0: <input file> <output file>');
@@ -76,9 +77,7 @@ const traceEventsToKeepInProcess = new Set([
  * @param {LH.TraceEvent[]} events
  */
 function filterOutUnnecessaryTasksByNameAndDuration(events) {
-  // TODO(phulce): update this once https://github.com/GoogleChrome/lighthouse/pull/5271 lands
-  const startedInPageEvt = events.find(evt => evt.name === 'TracingStartedInPage');
-  if (!startedInPageEvt) throw new Error('Could not find TracingStartedInPage');
+  const {startedInPageEvt} = TracingProcessor.findTracingStartedEvt(events);
 
   return events.filter(evt => {
     if (toplevelTaskNames.has(evt.name) && evt.dur < 1000) return false;