Download the host components when user tries to enable Me2Me host.

remoting/webapp/host_dispatcher.js

 // Copyright 2013 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
  * This class provides an interface between the HostController and either the
  * NativeMessaging Host or the Host NPAPI plugin, depending on whether or not
  * NativeMessaging is supported. Since the test for NativeMessaging support is
  * asynchronous, this class stores any requests on a queue, pending the result
@@ skipping 10 matching lines @@
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /**
  * @constructor
  * @param {function():remoting.HostPlugin} createPluginCallback Callback to
  *     instantiate the NPAPI plugin when NativeMessaging is determined to be
  *     unsupported.
  */
 remoting.HostDispatcher = function(createPluginCallback) {
-  /** @type {remoting.HostDispatcher} */
-  var that = this;
-
   /** @type {remoting.HostNativeMessaging} @private */
   this.nativeMessagingHost_ = new remoting.HostNativeMessaging();
 
   /** @type {remoting.HostPlugin} @private */
   this.npapiHost_ = null;
 
   /** @type {remoting.HostDispatcher.State} */
   this.state_ = remoting.HostDispatcher.State.UNKNOWN;
 
   /** @type {Array.<function()>} */
   this.pendingRequests_ = [];
 
+  this.createPluginCallback_ = createPluginCallback;
+
+  this.tryToInitialize_();
+}
+
+/** @enum {number} */
+remoting.HostDispatcher.State = {
+  UNKNOWN: 0,
+  NATIVE_MESSAGING: 1,
+  NPAPI: 2,
+  NOT_INSTALLED: 3
+};
+
+remoting.HostDispatcher.prototype.tryToInitialize_ = function() {
+  /** @type {remoting.HostDispatcher} */
+  var that = this;
+
+  if (this.state_ != remoting.HostDispatcher.State.UNKNOWN)
+    return;
+
   function sendPendingRequests() {
-    for (var i = 0; i < that.pendingRequests_.length; i++) {
-      that.pendingRequests_[i]();
+    var pendingRequests = that.pendingRequests_;
+    that.pendingRequests_ = [];
+    for (var i = 0; i < pendingRequests.length; i++) {
+      pendingRequests[i]();
     }
-    that.pendingRequests_ = null;
   }
 
   function onNativeMessagingInit() {
-    console.log('Native Messaging supported.');
     that.state_ = remoting.HostDispatcher.State.NATIVE_MESSAGING;
     sendPendingRequests();
   }
 
   function onNativeMessagingFailed(error) {
-    console.log('Native Messaging unsupported, falling back to NPAPI.');
-    that.npapiHost_ = createPluginCallback();
-    that.state_ = remoting.HostDispatcher.State.NPAPI;
+    that.npapiHost_ = that.createPluginCallback_();
+
+    that.state_ = that.npapiHost_ ? remoting.HostDispatcher.State.NPAPI
+                                  : remoting.HostDispatcher.State.NOT_INSTALLED;
     sendPendingRequests();
   }
 
   this.nativeMessagingHost_.initialize(onNativeMessagingInit,
                                        onNativeMessagingFailed);
 };
 
-/** @enum {number} */
-remoting.HostDispatcher.State = {
-  UNKNOWN: 0,
-  NATIVE_MESSAGING: 1,
-  NPAPI: 2
-};
-
 /**
  * @param {remoting.HostController.Feature} feature The feature to test for.
  * @param {function(boolean):void} onDone
  * @return {void}
  */
 remoting.HostDispatcher.prototype.hasFeature = function(
     feature, onDone) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.hasFeature.bind(this, feature, onDone));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       onDone(this.nativeMessagingHost_.hasFeature(feature));
       break;
     case remoting.HostDispatcher.State.NPAPI:
       // If this is an old NPAPI plugin that doesn't list supportedFeatures,
       // assume it is an old plugin that doesn't support any new feature.
       var supportedFeatures = [];
       if (typeof(this.npapiHost_.supportedFeatures) == 'string') {
         supportedFeatures = this.npapiHost_.supportedFeatures.split(' ');
       }
       onDone(supportedFeatures.indexOf(feature) >= 0);
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone(false);
+      break;
   }
 };
 
 /**
  * @param {function(string):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getHostName = function(onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.getHostName.bind(this, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getHostName(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.getHostName(onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {string} hostId
  * @param {string} pin
  * @param {function(string):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getPinHash =
     function(hostId, pin, onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.getPinHash.bind(this, hostId, pin, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getPinHash(hostId, pin, onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.getPinHash(hostId, pin, onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {function(string, string):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.generateKeyPair = function(onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.generateKeyPair.bind(this, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.generateKeyPair(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.generateKeyPair(onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {Object} config
  * @param {function(remoting.HostController.AsyncResult):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.updateDaemonConfig =
     function(config, onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.updateDaemonConfig.bind(this, config, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.updateDaemonConfig(config, onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.updateDaemonConfig(JSON.stringify(config), onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {function(Object):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getDaemonConfig = function(onDone, onError) {
   /**
@@ skipping 19 matching lines @@
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getDaemonConfig(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.getDaemonConfig(callbackForNpapi);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone({});

[Jamie, 2014/01/31 18:39:15]

Why is this not onError like the other cases? Maybe add a comment explaining the
discrepancy?

[Sergey Ulanov, 2014/01/31 23:34:17]

For most other things we can'd do anything without native components installed.
But we know that the host is not configured if it's not installed.

+      break;
   }
 };
 
 /**
  * @param {function(string):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getDaemonVersion = function(onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.getDaemonVersion.bind(this, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       onDone(this.nativeMessagingHost_.getDaemonVersion());
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.getDaemonVersion(onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {function(boolean, boolean, boolean):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getUsageStatsConsent =
     function(onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.getUsageStatsConsent.bind(this, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getUsageStatsConsent(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.getUsageStatsConsent(onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {Object} config
  * @param {boolean} consent
  * @param {function(remoting.HostController.AsyncResult):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.startDaemon =
     function(config, consent, onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.startDaemon.bind(this, config, consent, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.startDaemon(config, consent, onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.startDaemon(JSON.stringify(config), consent, onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {function(remoting.HostController.AsyncResult):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.stopDaemon = function(onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(this.stopDaemon.bind(this, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.stopDaemon(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.stopDaemon(onDone);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onError(remoting.Error.MISSING_PLUGIN);
+      break;
   }
 };
 
 /**
  * @param {function(remoting.HostController.State):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getDaemonState = function(onDone, onError) {
+  // If the host was in not-initialized state try initializing it again in case
+  // it was installed.
+  if (this.state_ == remoting.HostDispatcher.State.NOT_INSTALLED) {
+    this.state_ = remoting.HostDispatcher.State.UNKNOWN;
+    this.tryToInitialize_();
+  }
+
+  this.getDaemonStateInternal_(onDone, onError);
+}
+
+/**
+ * @param {function(remoting.HostController.State):void} onDone
+ * @param {function(remoting.Error):void} onError
+ * @return {void}
+ */
+remoting.HostDispatcher.prototype.getDaemonStateInternal_ =
+    function(onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
-          this.getDaemonState.bind(this, onDone, onError));
+          this.getDaemonStateInternal_.bind(this, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getDaemonState(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       // Call the callback directly, since NPAPI exposes the state directly as
       // a field member, rather than an asynchronous method.
       var state = this.npapiHost_.daemonState;
       if (state === undefined) {
         onError(remoting.Error.MISSING_PLUGIN);
       } else {
         onDone(state);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone(remoting.HostController.State.NOT_INSTALLED);
+      break;
   }
 };
 
 /**
  * @param {function(Array.<remoting.PairedClient>):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getPairedClients = function(onDone, onError) {
   /**
@@ skipping 20 matching lines @@
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getPairedClients(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.getPairedClients(callbackForNpapi);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone(remoting.HostController.State.NOT_INSTALLED);

[Jamie, 2014/01/31 18:39:15]

This is the wrong type for onDone. I think you meant to run onError. Have you
run this through jscompiler? I believe you can do it automatically now by
setting the run_jscompile GYP variable.

[Sergey Ulanov, 2014/01/31 23:34:17]

Done

+      break;
   }
 };
 
 /**
  * The pairing API returns a boolean to indicate success or failure, but
  * the JS API is defined in terms of onDone and onError callbacks. This
  * function converts one to the other.
  *
  * @param {function():void} onDone Success callback.
  * @param {function(remoting.Error):void} onError Error callback.
@@ skipping 25 matching lines @@
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.clearPairedClients(callback, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.clearPairedClients(callback);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone(remoting.HostController.State.NOT_INSTALLED);

[Jamie, 2014/01/31 18:39:15]

onDone take no parameters; perhaps you need to call onError?

[Sergey Ulanov, 2014/01/31 23:34:17]

Yes.

+      break;
   }
 };
 
 /**
  * @param {string} client
  * @param {function():void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.deletePairedClient =
     function(client, onDone, onError) {
   var callback =
       remoting.HostDispatcher.runCallback_.bind(null, onDone, onError);
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
         this.deletePairedClient.bind(this, client, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.deletePairedClient(client, callback, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       try {
         this.npapiHost_.deletePairedClient(client, callback);
       } catch (err) {
         onError(remoting.Error.MISSING_PLUGIN);
       }
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone(remoting.HostController.State.NOT_INSTALLED);

[Jamie, 2014/01/31 18:39:15]

onError?

[Sergey Ulanov, 2014/01/31 23:34:17]

Done.

+      break;
   }
 };
 
 /**
  * @param {function(string):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getHostClientId =
     function(onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.getHostClientId.bind(this, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getHostClientId(onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       // The NPAPI plugin is packaged with the webapp, not the host, so it
       // doesn't have access to the API keys baked into the installed host.
       onError(remoting.Error.UNEXPECTED);
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone(remoting.HostController.State.NOT_INSTALLED);

[Jamie, 2014/01/31 18:39:15]

onError?

[Sergey Ulanov, 2014/01/31 23:34:17]

Done.

+      break;
   }
 };
 
 /**
  * @param {string} authorizationCode
  * @param {function(string, string):void} onDone
  * @param {function(remoting.Error):void} onError
  * @return {void}
  */
 remoting.HostDispatcher.prototype.getCredentialsFromAuthCode =
     function(authorizationCode, onDone, onError) {
   switch (this.state_) {
     case remoting.HostDispatcher.State.UNKNOWN:
       this.pendingRequests_.push(
           this.getCredentialsFromAuthCode.bind(
               this, authorizationCode, onDone, onError));
       break;
     case remoting.HostDispatcher.State.NATIVE_MESSAGING:
       this.nativeMessagingHost_.getCredentialsFromAuthCode(
           authorizationCode, onDone, onError);
       break;
     case remoting.HostDispatcher.State.NPAPI:
       // The NPAPI plugin is packaged with the webapp, not the host, so it
       // doesn't have access to the API keys baked into the installed host.
       onError(remoting.Error.UNEXPECTED);
       break;
+    case remoting.HostDispatcher.State.NOT_INSTALLED:
+      onDone(remoting.HostController.State.NOT_INSTALLED);

[Jamie, 2014/01/31 18:39:15]

onError?

[Sergey Ulanov, 2014/01/31 23:34:17]

Done.

+      break;
   }
 };