Adds QueryResultManager support class for Media Router Dialog WebUI

chrome/browser/ui/webui/media_router/query_result_manager.h

+// Copyright 2015 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.
+
+#ifndef CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_QUERY_RESULT_MANAGER_H_
+#define CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_QUERY_RESULT_MANAGER_H_
+
+#include <map>
+#include <set>
+#include <vector>
+
+#include "base/gtest_prod_util.h"
+#include "base/memory/linked_ptr.h"
+#include "base/observer_list.h"
+#include "base/threading/thread_checker.h"
+#include "chrome/browser/media/router/media_routes_observer.h"
+#include "chrome/browser/media/router/media_sink.h"
+#include "chrome/browser/media/router/media_source.h"
+#include "chrome/browser/ui/webui/media_router/media_cast_mode.h"
+#include "chrome/browser/ui/webui/media_router/media_sink_with_cast_modes.h"
+
+namespace media_router {
+
+class MediaRouter;
+class MediaSinksObserver;
+struct RoutesQueryResult;
+struct SinksQueryResult;
+
+// The Media Router dialog allows the user to initiate casting using one of
+// several actions (each represented by a cast mode).  Each cast mode is
+// associated with a media source.  This class allows the dialog to receive
+// lists of MediaSinks compatible with the cast modes available through the
+// dialog.
+//
+// Typical use:
+//
+//   QueryResultManager::Observer* observer = ...;
+//   QueryResultManager result_manager(router);
+//   result_manager.AddObserver(observer);
+//   result_manager.StartSinksQuery(MediaCastMode::DEFAULT,
+//       ForPresentationUrl("http://google.com"));
+//   result_manager.StartSinksQuery(MediaCastMode::TAB_MIRROR,
+//       ForTabMediaSource(123));
+//   ...
+//   [Updates will be received by observer via OnResultsUpdated()]
+//   ...
+//   [When info on MediaSource is needed, i.e. when requesting route for a mode]
+//   CastModeSet cast_modes;
+//   result_manager.GetSupportedCastModes(&cast_modes);
+//   [Logic to select a MediaCastMode from the set]
+//   MediaSource source = result_manager.GetSourceForCastMode(
+//       MediaCastMode::TAB_MIRROR);
+//   if (!source.Empty()) {
+//     ...
+//   }
+//
+// Not thread-safe.  Must be used on a single thread.
+class QueryResultManager {
+ public:
+  class Observer {
+   public:
+    virtual ~Observer() {}
+
+    // Updated results have been received.
+    // |sinks|: List of sinks and the cast modes they are compatible with.
+    virtual void OnResultsUpdated(
+        const std::vector<MediaSinkWithCastModes>& sinks) = 0;
+  };
+
+  explicit QueryResultManager(MediaRouter* media_router);
+  ~QueryResultManager();
+
+  // Adds/removes an observer that is notified with query results.
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  // Requests a list of MediaSinks compatible with |source| for |cast_mode|.
+  // Results are sent to all observers registered with AddObserver().
+  //
+  // May start a new query in the Media Router for the registered source if
+  // there is no existing query for it.  If there is an existing query for
+  // |cast_mode|, it is stopped.
+  //
+  // If |source| is empty, no new queries are begun.
+  void StartSinksQuery(MediaCastMode cast_mode, const MediaSource& source);
+
+  // Stops notifying observers for |cast_mode|.
+  void StopSinksQuery(MediaCastMode cast_mode);
+
+  // Gets the set of cast modes that are being actively queried. |cast_mode_set|
+  // should be empty.
+  void GetSupportedCastModes(CastModeSet* cast_modes) const;
+
+  // Returns the MediaSource registered for |cast_mode|.  Returns an empty
+  // MediaSource if there is none.
+  MediaSource GetSourceForCastMode(MediaCastMode cast_mode) const;
+
+ private:
+  class CastModeMediaSinksObserver;
+
+  FRIEND_TEST_ALL_PREFIXES(QueryResultManagerTest, Observers);
+  FRIEND_TEST_ALL_PREFIXES(QueryResultManagerTest, StartRoutesDiscovery);
+  FRIEND_TEST_ALL_PREFIXES(QueryResultManagerTest, MultipleQueries);
+
+  // Sets the media source for |cast_mode|.
+  void SetSourceForCastMode(MediaCastMode cast_mode, const MediaSource& source);
+
+  // Stops and destroys the MediaSinksObserver for |cast_mode|.
+  void RemoveObserverForCastMode(MediaCastMode cast_mode);
+
+  // Returns true if the |entry|'s sink is compatible with at least one cast
+  // mode.
+  bool IsValid(const MediaSinkWithCastModes& entry) const;
+
+  // Modifies the current set of results with |result| associated with
+  // |cast_mode|.
+  void UpdateWithSinksQueryResult(MediaCastMode cast_mode,
+                                  const std::vector<MediaSink>& result);
+
+  // Notifies observers that results have been updated.
+  void NotifyOnResultsUpdated();
+
+  // MediaSinksObservers that listens for compatible MediaSink updates.
+  // Each observer is associated with a MediaCastMode. Results received by
+  // observers are propagated back to this class.
+  // TODO(mfoltz): Remove linked_ptr when there is a ScopedPtrMap available.
+  std::map<MediaCastMode, linked_ptr<MediaSinksObserver>> sinks_observers_;
+
+  // Holds registrations of MediaSources for cast modes.
+  std::map<MediaCastMode, MediaSource> cast_mode_sources_;
+
+  // Holds all known sinks and their associated cast modes.
+  std::map<MediaSinkId, MediaSinkWithCastModes> all_sinks_;
+
+  // Registered observers.
+  ObserverList<Observer> observers_;
+
+  // Not owned by this object.
+  MediaRouter* router_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(QueryResultManager);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_QUERY_RESULT_MANAGER_H_