1 files changed, 187 insertions, 0 deletions
diff --git a/devtools/server/actors/perf.js b/devtools/server/actors/perf.js
new file mode 100644
index 0000000000..3f561256c9
--- /dev/null
+++ b/devtools/server/actors/perf.js
@@ -0,0 +1,187 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+
+const { Actor } = require("resource://devtools/shared/protocol.js");
+const { perfSpec } = require("resource://devtools/shared/specs/perf.js");
+
+loader.lazyRequireGetter(
+  this,
+  "RecordingUtils",
+  "resource://devtools/shared/performance-new/recording-utils.js"
+);
+
+// Some platforms are built without the Gecko Profiler.
+const IS_SUPPORTED_PLATFORM = "nsIProfiler" in Ci;
+
+/**
+ * The PerfActor wraps the Gecko Profiler interface (aka Services.profiler).
+ */
+exports.PerfActor = class PerfActor extends Actor {
+  constructor(conn) {
+    super(conn, perfSpec);
+
+    // Only setup the observers on a supported platform.
+    if (IS_SUPPORTED_PLATFORM) {
+      this._observer = {
+        observe: this._observe.bind(this),
+      };
+      Services.obs.addObserver(this._observer, "profiler-started");
+      Services.obs.addObserver(this._observer, "profiler-stopped");
+    }
+  }
+
+  destroy() {
+    super.destroy();
+
+    if (!IS_SUPPORTED_PLATFORM) {
+      return;
+    }
+    Services.obs.removeObserver(this._observer, "profiler-started");
+    Services.obs.removeObserver(this._observer, "profiler-stopped");
+  }
+
+  startProfiler(options) {
+    if (!IS_SUPPORTED_PLATFORM) {
+      return false;
+    }
+
+    // For a quick implementation, decide on some default values. These may need
+    // to be tweaked or made configurable as needed.
+    const settings = {
+      entries: options.entries || 1000000,
+      duration: options.duration || 0,
+      interval: options.interval || 1,
+      features: options.features || [
+        "js",
+        "stackwalk",
+        "cpu",
+        "responsiveness",
+      ],
+      threads: options.threads || ["GeckoMain", "Compositor"],
+      activeTabID: RecordingUtils.getActiveBrowserID(),
+    };
+
+    try {
+      // This can throw an error if the profiler is in the wrong state.
+      Services.profiler.StartProfiler(
+        settings.entries,
+        settings.interval,
+        settings.features,
+        settings.threads,
+        settings.activeTabID,
+        settings.duration
+      );
+    } catch (e) {
+      // In case any errors get triggered, bailout with a false.
+      return false;
+    }
+
+    return true;
+  }
+
+  stopProfilerAndDiscardProfile() {
+    if (!IS_SUPPORTED_PLATFORM) {
+      return;
+    }
+    Services.profiler.StopProfiler();
+  }
+
+  /**
+   * @type {string} debugPath
+   * @type {string} breakpadId
+   * @returns {Promise<[number[], number[], number[]]>}
+   */
+  async getSymbolTable(debugPath, breakpadId) {
+    const [addr, index, buffer] = await Services.profiler.getSymbolTable(
+      debugPath,
+      breakpadId
+    );
+    // The protocol does not support the transfer of typed arrays, so we convert
+    // these typed arrays to plain JS arrays of numbers now.
+    // Our return value type is declared as "array:array:number".
+    return [Array.from(addr), Array.from(index), Array.from(buffer)];
+  }
+
+  async getProfileAndStopProfiler() {
+    if (!IS_SUPPORTED_PLATFORM) {
+      return null;
+    }
+
+    // Pause profiler before we collect the profile, so that we don't capture
+    // more samples while the parent process or android threads wait for subprocess profiles.
+    Services.profiler.Pause();
+
+    let profile;
+    try {
+      // Attempt to pull out the data.
+      profile = await Services.profiler.getProfileDataAsync();
+
+      if (Object.keys(profile).length === 0) {
+        console.error(
+          "An empty object was received from getProfileDataAsync.getProfileDataAsync(), " +
+            "meaning that a profile could not successfully be serialized and captured."
+        );
+        profile = null;
+      }
+    } catch (e) {
+      // Explicitly set the profile to null if there as an error.
+      profile = null;
+      console.error(`There was an error fetching a profile`, e);
+    }
+
+    // Stop and discard the buffers.
+    Services.profiler.StopProfiler();
+
+    // Returns a profile when successful, and null when there is an error.
+    return profile;
+  }
+
+  isActive() {
+    if (!IS_SUPPORTED_PLATFORM) {
+      return false;
+    }
+    return Services.profiler.IsActive();
+  }
+
+  isSupportedPlatform() {
+    return IS_SUPPORTED_PLATFORM;
+  }
+
+  /**
+   * Watch for events that happen within the browser. These can affect the
+   * current availability and state of the Gecko Profiler.
+   */
+  _observe(subject, topic, _data) {
+    // Note! If emitting new events make sure and update the list of bridged
+    // events in the perf actor.
+    switch (topic) {
+      case "profiler-started":
+        const param = subject.QueryInterface(Ci.nsIProfilerStartParams);
+        this.emit(
+          topic,
+          param.entries,
+          param.interval,
+          param.features,
+          param.duration,
+          param.activeTabID
+        );
+        break;
+      case "profiler-stopped":
+        this.emit(topic);
+        break;
+    }
+  }
+
+  /**
+   * Lists the supported features of the profiler for the current browser.
+   * @returns {string[]}
+   */
+  getSupportedFeatures() {
+    if (!IS_SUPPORTED_PLATFORM) {
+      return [];
+    }
+    return Services.profiler.GetFeatures();
+  }
+};