tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

perf.js (2623B)

      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 /**
      8 * @typedef {import("perf").BulkReceiving} BulkReceiving
      9 */
     10 
     11 const {
     12  FrontClassWithSpec,
     13  registerFront,
     14 } = require("resource://devtools/shared/protocol.js");
     15 const { perfSpec } = require("resource://devtools/shared/specs/perf.js");
     16 
     17 class PerfFront extends FrontClassWithSpec(perfSpec) {
     18  constructor(client, targetFront, parentFront) {
     19    super(client, targetFront, parentFront);
     20 
     21    // Attribute name from which to retrieve the actorID out of the target actor's form
     22    this.formAttributeName = "perfActor";
     23  }
     24 
     25  async getProfileAndStopProfiler() {
     26    const handle = await this.startCaptureAndStopProfiler();
     27 
     28    // Start both calls in parallel
     29    const profilePromise = this.getPreviouslyCapturedProfileDataBulk(handle);
     30    const additionalInformationPromise =
     31      this.getPreviouslyRetrievedAdditionalInformation(handle);
     32 
     33    // But make sure we wait until the end of both calls even in case of an error.
     34    const [profileResult, additionalInformationResult] =
     35      await Promise.allSettled([profilePromise, additionalInformationPromise]);
     36 
     37    if (profileResult.status === "rejected") {
     38      throw profileResult.reason;
     39    }
     40 
     41    if (additionalInformationResult.status === "rejected") {
     42      throw additionalInformationResult.reason;
     43    }
     44 
     45    return {
     46      profile: profileResult.value,
     47      additionalInformation: additionalInformationResult.value,
     48    };
     49  }
     50 
     51  /**
     52   * This implements the retrieval of the profile data using the bulk protocol.
     53   *
     54   * @param {number} handle THe handle returned by startCaptureAndStopProfiler
     55   */
     56  async getPreviouslyCapturedProfileDataBulk(handle) {
     57    /**
     58     * @typedef {BulkReceiving}
     59     */
     60    const profileResult = await super.getPreviouslyCapturedProfileDataBulk(
     61      handle
     62    );
     63 
     64    if (!profileResult) {
     65      throw new Error(
     66        "this.conn.request returns null or undefined, this is unexpected."
     67      );
     68    }
     69 
     70    if (!profileResult.length) {
     71      throw new Error(
     72        "The profile result is an empty buffer, this is unexpected."
     73      );
     74    }
     75 
     76    // We need to copy the data out of the stream we get using the bulk API.
     77    // Note that the profile data is gzipped, but the profiler's frontend code
     78    // knows how to deal with it.
     79    const buffer = new ArrayBuffer(profileResult.length);
     80    await profileResult.copyToBuffer(buffer);
     81    return buffer;
     82  }
     83 }
     84 
     85 registerFront(PerfFront);