tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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jstracer-state.js (2872B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 
      5 "use strict";
      6 
      7 const { JSTracer } = ChromeUtils.importESModule(
      8  "resource://devtools/server/tracer/tracer.sys.mjs",
      9  { global: "contextual" }
     10 );
     11 
     12 const Targets = require("resource://devtools/server/actors/targets/index.js");
     13 loader.lazyRequireGetter(
     14  this,
     15  "TRACER_LOG_METHODS",
     16  "resource://devtools/shared/specs/tracer.js",
     17  true
     18 );
     19 
     20 class TracingStateWatcher {
     21  /**
     22   * Start watching for tracing state changes for a given target actor.
     23   *
     24   * @param TargetActor targetActor
     25   *        The target actor from which we should observe
     26   * @param Object options
     27   *        Dictionary object with following attributes:
     28   *        - onAvailable: mandatory function
     29   *          This will be called for each resource.
     30   */
     31  async watch(targetActor, { onAvailable }) {
     32    // Bug 1874204: tracer doesn't support tracing content process from the browser toolbox just yet
     33    if (targetActor.targetType == Targets.TYPES.PROCESS) {
     34      return;
     35    }
     36 
     37    this.targetActor = targetActor;
     38    this.onAvailable = onAvailable;
     39 
     40    this.tracingListener = {
     41      onTracingToggled: this.onTracingToggled.bind(this),
     42    };
     43    JSTracer.addTracingListener(this.tracingListener);
     44  }
     45 
     46  /**
     47   * Stop watching for tracing state
     48   */
     49  destroy() {
     50    if (!this.tracingListener) {
     51      return;
     52    }
     53    JSTracer.removeTracingListener(this.tracingListener);
     54  }
     55 
     56  /**
     57   * Be notified by the underlying JavaScriptTracer class
     58   * in case it stops by itself, instead of being stopped when the Actor's stopTracing
     59   * method is called by the user.
     60   *
     61   * @param {boolean} enabled
     62   *        True if the tracer starts tracing, false it it stops.
     63   * @param {string} reason
     64   *        Optional string to justify why the tracer stopped.
     65   */
     66  async onTracingToggled(enabled, reason) {
     67    const tracerActor = this.targetActor.getTargetScopedActor("tracer");
     68    const logMethod = tracerActor?.getLogMethod();
     69 
     70    // JavascriptTracer only supports recording once in the same process/thread.
     71    // If we open another DevTools, on the same process, we would receive notification
     72    // about a JavascriptTracer controlled by another toolbox's tracer actor.
     73    // Ignore them as our current tracer actor didn't start tracing.
     74    if (!logMethod) {
     75      return;
     76    }
     77 
     78    this.onAvailable([
     79      {
     80        enabled,
     81        logMethod,
     82        profile:
     83          logMethod == TRACER_LOG_METHODS.PROFILER && !enabled
     84            ? await tracerActor.getProfile()
     85            : undefined,
     86        timeStamp: ChromeUtils.dateNow(),
     87        reason,
     88        traceValues: tracerActor.traceValues,
     89      },
     90    ]);
     91  }
     92 }
     93 
     94 module.exports = TracingStateWatcher;