Cleanup cast idle state

This simplifies the logic for idle state, fixes some buggy idle state
transitions, and moves the idle logic into CastReceiver (with a little
support from Player).

Issue #261

Change-Id: Ic2729a4235c746ad46353bdf5dc7b605ab31f3ef

demo/receiver_app.js

@@ -85,13 +85,6 @@ ShakaReceiver.prototype.init = function() {
   this.video_.addEventListener(
       'emptied', this.onPlayStateChange_.bind(this));
 
-  this.video_.addEventListener(
-      'canplay', this.checkIdle_.bind(this));
-  this.video_.addEventListener(
-      'emptied', this.checkIdle_.bind(this));
-  this.video_.addEventListener(
-      'ended', this.checkIdle_.bind(this));
-
   this.receiver_ = new shaka.cast.CastReceiver(
       this.video_, this.player_, this.appDataCallback_.bind(this));
   this.receiver_.addEventListener(
@@ -121,29 +114,15 @@ ShakaReceiver.prototype.appDataCallback_ = function(appData) {
 
 /** @private */
 ShakaReceiver.prototype.checkIdle_ = function() {
-  var connected = this.receiver_.isConnected();
-  var loaded = this.video_.readyState > 0;
-  var ended = this.video_.ended;
-
-  var idle = !loaded || (!connected && ended);
-
   console.debug('status changed',
-                'connected=', connected,
-                'loaded=', loaded,
-                'ended=', ended,
-                'idle=', idle);
-
-  // If something is loaded, but we've just gone idle, unload the content, show
-  // the idle card, and set a timer to close the app.
-  if (idle && loaded) {
-    this.player_.unload();
+                'idle=', this.receiver_.isIdle());
+
+  // If the app is idle, show the idle card and set a timer to close the app.
+  // Otherwise, hide the idle card and cancel the timer.
+  if (this.receiver_.isIdle()) {
     this.idle_.style.display = 'block';
     this.startIdleTimer_();
-  }
-
-  // If we are no longer idle, hide the idle card, and make sure we cancel any
-  // timers that would close the app.
-  if (!idle) {
+  } else {
     this.idle_.style.display = 'none';
     this.cancelIdleTimer_();
   }

lib/cast/cast_receiver.js

@@ -61,6 +61,9 @@ shaka.cast.CastReceiver = function(video, player, opt_appDataCallback) {
   /** @private {boolean} */
   this.isConnected_ = false;
 
+  /** @private {boolean} */
+  this.isIdle_ = true;
+
   /** @private {cast.receiver.CastMessageBus} */
   this.bus_ = null;
 
@@ -81,6 +84,16 @@ shaka.cast.CastReceiver.prototype.isConnected = function() {
 };
 
 
+/**
+ * @return {boolean} True if the receiver is not currently doing loading or
+ *   playing anything.
+ * @export
+ */
+shaka.cast.CastReceiver.prototype.isIdle = function() {
+  return this.isIdle_;
+};
+
+
 /**
  * Destroys the underlying Player, then terminates the cast receiver app.
  *
@@ -99,6 +112,7 @@ shaka.cast.CastReceiver.prototype.destroy = function() {
   this.targets_ = null;
   this.appDataCallback_ = null;
   this.isConnected_ = false;
+  this.isIdle_ = true;
   this.bus_ = null;
   this.pollTimerId_ = null;
 
@@ -146,6 +160,26 @@ shaka.cast.CastReceiver.prototype.init_ = function() {
   // higher res anyway, given that the device only outputs 1080p to begin with.
   this.player_.setMaxHardwareResolution(1920, 1080);
 
+  // Maintain idle state.
+  this.player_.addEventListener('loading', function() {
+    this.isIdle_ = false;
+    this.onCastStatusChanged_();
+  }.bind(this));
+  this.player_.addEventListener('unloading', function() {
+    this.isIdle_ = true;
+    this.onCastStatusChanged_();
+  }.bind(this));
+  this.video_.addEventListener('ended', function() {
+    // Go idle 5 seconds after 'ended', assuming we haven't started again or
+    // been destroyed.
+    window.setTimeout(function() {
+      if (this.video_ && this.video_.ended) {
+        this.isIdle_ = true;
+        this.onCastStatusChanged_();
+      }
+    }.bind(this), 5000);
+  }.bind(this));
+
   // Do not start polling until after the sender's 'init' message is handled.
 };
 
@@ -163,8 +197,13 @@ shaka.cast.CastReceiver.prototype.onSendersChanged_ = function() {
  * @private
  */
 shaka.cast.CastReceiver.prototype.onCastStatusChanged_ = function() {
-  var event = new shaka.util.FakeEvent('caststatuschanged');
-  this.dispatchEvent(event);
+  // Do this asynchronously so that synchronous changes to idle state (such as
+  // Player calling unload() as part of load()) are coalesced before the event
+  // goes out.
+  Promise.resolve().then(function() {
+    var event = new shaka.util.FakeEvent('caststatuschanged');
+    this.dispatchEvent(event);
+  }.bind(this));
 };
 
 

lib/player.js

@@ -229,6 +229,26 @@ shaka.Player.version = GIT_VERSION;
  */
 
 
+/**
+ * @event shaka.Player.LoadingEvent
+ * @description Fired when the player begins loading.
+ *   Used by the Cast receiver to determine idle state.
+ * @property {string} type
+ *   'loading'
+ * @exportDoc
+ */
+
+
+/**
+ * @event shaka.Player.UnloadingEvent
+ * @description Fired when the player unloads or fails to load.
+ *   Used by the Cast receiver to determine idle state.
+ * @property {string} type
+ *   'unloading'
+ * @exportDoc
+ */
+
+
 /**
  * @event shaka.Player.TextTrackVisibilityEvent
  * @description Fired when text track visibility changes.
@@ -345,6 +365,7 @@ shaka.Player.prototype.load = function(manifestUri, opt_startTime,
   var unloadPromise = this.unload();
   var loadChain = new shaka.util.CancelableChain();
   this.loadChain_ = loadChain;
+  this.dispatchEvent(new shaka.util.FakeEvent('loading'));
 
   return loadChain.then(function() {
     return unloadPromise;
@@ -415,6 +436,7 @@ shaka.Player.prototype.load = function(manifestUri, opt_startTime,
     // If we haven't started another load, clear the loadChain_ member.
     if (this.loadChain_ == loadChain) {
       this.loadChain_ = null;
+      this.dispatchEvent(new shaka.util.FakeEvent('unloading'));
     }
     return Promise.reject(error);
   }.bind(this));
@@ -736,6 +758,7 @@ shaka.Player.prototype.isBuffering = function() {
  */
 shaka.Player.prototype.unload = function() {
   if (this.destroyed_) return Promise.resolve();
+  this.dispatchEvent(new shaka.util.FakeEvent('unloading'));
 
   if (this.loadChain_) {
     // A load is in progress.  Cancel it, then reset the streaming system.

test/cast/cast_receiver_unit.js

@@ -133,21 +133,53 @@ describe('CastReceiver', function() {
   });
 
   describe('"caststatuschanged" event', function() {
-    it('is triggered when senders connect or disconnect', function() {
+    it('is triggered when senders connect or disconnect', function(done) {
       checkChromeOrChromecast();
-      fakeConnectedSenders(0);
+      var listener = jasmine.createSpy('listener');
+      receiver.addEventListener('caststatuschanged', listener);
+
+      shaka.test.Util.delay(0.2).then(function() {
+        expect(listener).not.toHaveBeenCalled();
+        fakeConnectedSenders(1);
+        return shaka.test.Util.delay(0.2);
+      }).then(function() {
+        expect(listener).toHaveBeenCalled();
+        listener.calls.reset();
+        mockReceiverManager.onSenderDisconnected();
+        return shaka.test.Util.delay(0.2);
+      }).then(function() {
+        expect(listener).toHaveBeenCalled();
+      }).catch(fail).then(done);
+    });
 
+    it('is triggered when idle state changes', function(done) {
+      checkChromeOrChromecast();
       var listener = jasmine.createSpy('listener');
       receiver.addEventListener('caststatuschanged', listener);
-      expect(listener).not.toHaveBeenCalled();
 
-      mockReceiverManager.onSenderConnected();
-      expect(listener).toHaveBeenCalled();
+      var fakeLoadingEvent = {type: 'loading'};
+      var fakeUnloadingEvent = {type: 'unloading'};
+      var fakeEndedEvent = {type: 'ended'};
 
-      listener.calls.reset();
-      mockReceiverManager.onSenderDisconnected();
-      expect(listener).toHaveBeenCalled();
-    });
+      shaka.test.Util.delay(0.2).then(function() {
+        expect(listener).not.toHaveBeenCalled();
+        mockPlayer.listeners['loading'](fakeLoadingEvent);
+        return shaka.test.Util.delay(0.2);
+      }).then(function() {
+        expect(listener).toHaveBeenCalled();
+        listener.calls.reset();
+        mockPlayer.listeners['unloading'](fakeUnloadingEvent);
+        return shaka.test.Util.delay(0.2);
+      }).then(function() {
+        expect(listener).toHaveBeenCalled();
+        listener.calls.reset();
+        mockVideo.ended = true;
+        mockVideo.listeners['ended'](fakeEndedEvent);
+        return shaka.test.Util.delay(5.2);  // There is a long delay for 'ended'
+      }).then(function() {
+        expect(listener).toHaveBeenCalled();
+      }).catch(fail).then(done);
+    }, /* timeout ms */ 8000);
   });
 
   describe('local events', function() {