Add a StateManager for managing hotwording state based on various factors

chrome/browser/resources/hotword/state_manager.js

Index: chrome/browser/resources/hotword/state_manager.js
diff --git a/chrome/browser/resources/hotword/state_manager.js b/chrome/browser/resources/hotword/state_manager.js
new file mode 100644
index 0000000000000000000000000000000000000000..964e7dcf04abeb26bb26b57e7f31506253f9f33a
--- /dev/null
+++ b/chrome/browser/resources/hotword/state_manager.js
@@ -0,0 +1,184 @@
+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview Class to manage hotwording state.
+ */
+
+cr.define('hotword', function() {
+'use strict';

[Dan Beam, 2014/08/26 18:40:51]

this code should probably be indented because it's inside a function.

i can see the rationale of treating this like a C++ namespace (which we don't
indent), but all the rest of webui code currently idents cr.define()s.

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+
+/**
+ * @constructor
+ * @struct
+ */
+function StateManager() {
+  /**
+   * Current state.
+   * @private {hotword.StateManager.State_}
+   */
+  this.state_ = State_.STOPPED;
+
+  /**
+   * Current hotwording status.
+   * @private {chrome.hotwordPrivate.StatusDetails}
+   */
+  this.hotwordStatus_ = null;
+
+  /**
+   * NaCl plugin manager.
+   * @private {?hotword.NaClManager}

[Dan Beam, 2014/08/26 18:40:51]

add ? to |this.hotwordStatus_|'s type or remove from here

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+   */
+  this.pluginManager_ = null;
+
+  // Get the initial status.
+  chrome.hotwordPrivate.getStatus(this.handleStatus_.bind(this));
+}
+

[Dan Beam, 2014/08/26 18:40:51]

/**
 * @enum {number}
 * @private
 */

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+StateManager.State_ = {
+  STOPPED: 0,
+  STARTING: 1,
+  RUNNING: 2,
+  ERROR: 3,
+};
+var State_ = StateManager.State_;
+
+/**
+ * Request status details update. Intended to be called from the
+ * hotwordPrivate.onEnabledChanged() event.
+ */
+StateManager.prototype.updateStatus = function() {
+  chrome.hotwordPrivate.getStatus(this.handleStatus_.bind(this));
+};
+
+/**
+ * Callback for hotwordPrivate.getStatus() function.
+ * @param {chrome.hotwordPrivate.StatusDetails} status Current hotword status.
+ * @private
+ */
+StateManager.prototype.handleStatus_ = function(status) {
+  this.hotwordStatus_ = status;
+  this.updateStateFromStatus_();
+};
+
+/**
+ * Updates state based on the current status.
+ * @private
+ */
+StateManager.prototype.updateStateFromStatus_ = function() {
+ if (this.hotwordStatus_.enabled) {

[Dan Beam, 2014/08/26 18:40:52]

indent off (needs 1 more space)

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

WTF? How did that end up there? Done.

+   // Hotwording is enabled.
+   // TODO(amistry): Have a separate alwaysOnEnabled flag. For now, treat
+   // "enabled" as "always on enabled".
+   this.startDetector_();
+ } else {
+   // Not enabled. Shut down if running.
+   this.shutdownDetector_();
+ }
+};
+
+/**
+ * Starts the hotword detector.
+ * @private
+ */
+StateManager.prototype.startDetector_ = function() {
+  // Last attempt to start detector resulted in an error.
+  if (this.state_ == State_.ERROR) {
+    // TODO(amistry): Do some error rate tracking here and disable the extension
+    // if we error too often.

[Dan Beam, 2014/08/26 18:40:52]

is there some code you meant to put here?

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Not yet. I'm not ready to fill in that kind of detail. Also, I think that logic
is more complicated than I want to put in this CL.

+  }
+
+  if (this.pluginManager_ == null) {

[Dan Beam, 2014/08/26 18:40:52]

if (!this.pluginManager_) {

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+    this.state_ = State_.STARTING;
+    this.pluginManager_ = new hotword.NaClManager();
+    this.pluginManager_.addEventListener(hotword.constants.Event.READY,
+                                    this.onReady_.bind(this));

[Dan Beam, 2014/08/26 18:40:52]

indent off x 3

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+    this.pluginManager_.addEventListener(hotword.constants.Event.ERROR,
+                                    this.onError_.bind(this));
+    this.pluginManager_.addEventListener(hotword.constants.Event.TRIGGER,
+                                    this.onTrigger_.bind(this));
+    chrome.runtime.getPlatformInfo(function(platform) {
+      var naclArch = platform.nacl_arch;
+
+      // googDucking set to false so that audio output level from other tabs is
+      // not affected when hotword is enabled. https://crbug.com/357773
+      // src.chromium.org/svn/trunk/src/content/common/media/media_stream_options.cc

[Dan Beam, 2014/08/26 18:40:52]

use bit.ly or just put local path.

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+      var constraints = /** @type {googMediaStreamConstraints} */
+          ({audio: {optional: [{ googDucking: false}] }});

[Dan Beam, 2014/08/26 18:40:52]

no \s after { or }

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+      navigator.webkitGetUserMedia(
+          /** @type {MediaStreamConstraints} */ (constraints),
+          function(stream) {
+            if (!this.pluginManager_.initialize(naclArch, stream)) {
+              this.state_ = State_.ERROR;
+              this.pluginManager_.shutdown();
+              this.pluginManager_ = null;

[Dan Beam, 2014/08/26 18:40:51]

nit: this code seems to be repeated a lot:

  this.pluginManager_.shutdown();
  this.pluginManager_ = null;

how about:

  /** @private */
  shutdownPluginManager_: function() {
    if (this.pluginManager_)
      this.pluginManager_.shutdown();
    this.pluginManager_ = null;
  },

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+            }
+          }.bind(this),
+          function(error) {
+            this.state_ = State_.ERROR;
+            this.pluginManager_ = null;
+          }.bind(this));
+    }.bind(this));
+  } else if (this.state_ != State_.STARTING) {
+    // Don't try to start a starting detector.
+    this.state_ = State_.RUNNING;
+    this.pluginManager_.startRecognizer();
+  }
+};
+
+/**
+ * Shuts down the hotword detector.
+ * @private
+ */
+StateManager.prototype.shutdownDetector_ = function() {
+  this.state_ = State_.STOPPED;
+  if (this.pluginManager_ != null) {
+    this.pluginManager_.shutdown();
+    this.pluginManager_ = null;
+  }
+};
+
+/**
+ * Handle the hotword plugin being ready to start.
+ * @private
+ */
+StateManager.prototype.onReady_ = function() {
+  if (this.state_ != State_.STARTING) {
+    // Shouldn't be running while starting.
+    assert(this.state_ != State_.RUNNING);
+    this.pluginManager_.shutdown();
+    this.pluginManager_ = null;
+    return;
+  }
+  this.state_ = State_.RUNNING;
+  this.pluginManager_.startRecognizer();
+};
+
+/**
+ * Handle an error from the hotword plugin.
+ * @private
+ */
+StateManager.prototype.onError_ = function() {
+  this.state_ = State_.ERROR;
+  this.pluginManager_.shutdown();
+  this.pluginManager_ = null;
+};
+
+/**
+ * Handle hotword triggering.
+ * @private
+ */
+StateManager.prototype.onTrigger_ = function() {
+  assert(this.pluginManager_ != null);

[Dan Beam, 2014/08/26 18:40:52]

assert(this.pluginManager_)

[Anand Mistry (off Chromium), 2014/08/27 07:10:56]

Done.

+  // Detector implicitly stops when the hotword is detected.
+  this.state_ = State_.STOPPED;
+
+  chrome.hotwordPrivate.notifyHotwordRecognition('search', function() {});
+};
+
+return {
+  StateManager: StateManager
+};
+
+});