[Media Router] Add MediaSink subtypes

chrome/browser/media/router/discovery/media_sink_internal.h

+// Copyright 2017 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_MEDIA_ROUTER_DISCOVERY_MEDIA_SINK_INTERNAL_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_MEDIA_SINK_INTERNAL_H_
+
+#include "chrome/browser/media/router/media_sink.h"
+#include "net/base/ip_address.h"
+#include "url/gurl.h"
+
+namespace media_router {
+
+// Extra data for DIAL media sink.
+struct DialSinkExtraData {
+  net::IPAddress ip_address;
+
+  // Model name of the sink.
+  std::string model_name;
+
+  // The base URL used for DIAL operations.
+  GURL app_url;
+
+  DialSinkExtraData();
+  DialSinkExtraData(const DialSinkExtraData& other);
+  ~DialSinkExtraData();
+};
+
+// Extra data for cast media sink.
+struct CastSinkExtraData {
+  net::IPAddress ip_address;
+
+  // Model name of the sink.
+  std::string model_name;
+
+  // A bit vector representing the capabilities of the sink. The values are
+  // defined in media_router.mojom.
+  int capabilities = 0;
+
+  // ID of Cast channel opened for the sink. The caller must set this value to a
+  // valid cast_channel_id. The cast_channel_id may change over time as the
+  // browser reconnects to a device.
+  int cast_channel_id = 0;
+
+  CastSinkExtraData();
+  CastSinkExtraData(const CastSinkExtraData& other);
+  ~CastSinkExtraData();
+};
+
+// Represents a media sink discovered by MediaSinkService. It is used by
+// MediaSinkService to push MediaSinks with extra data to the
+// MediaRouteProvider, and it is not exposed to users of MediaRouter.
+class MediaSinkInternal {
+ public:
+  // Used by mojo.
+  MediaSinkInternal();
+
+  // Used by unit test.
+  explicit MediaSinkInternal(const MediaSink& sink);
+
+  // Used by MediaSinkService to create media sinks.
+  MediaSinkInternal(const MediaSink& sink, const DialSinkExtraData& dial_data);
+  MediaSinkInternal(const MediaSink& sink, const CastSinkExtraData& cast_data);
+
+  // Used to push instance of this class into vector.
+  MediaSinkInternal(const MediaSinkInternal& other);
+
+  ~MediaSinkInternal();
+
+  MediaSinkInternal& operator=(const MediaSinkInternal& other);
+
+  void set_sink(const MediaSink& sink);
+  const MediaSink& sink() const { return sink_; }
+
+  void set_dial_data(const DialSinkExtraData& dial_data);
+
+  // Must only be called if the sink is a DIAL sink.
+  const DialSinkExtraData& dial_data() const;
+
+  void set_cast_data(const CastSinkExtraData& cast_data);
+
+  // Must only be called if the sink is a Cast sink.
+  const CastSinkExtraData& cast_data() const;
+
+  bool is_dial_sink() const { return dial_data_ && !cast_data_; }
+  bool is_cast_sink() const { return cast_data_ && !dial_data_; }
+
+  static bool IsValidSinkId(const std::string& sink_id);
+
+ private:
+  MediaSink sink_;
+
+  // Set if sink is DIAL sink.

[dcheng, 2017/03/03 10:37:10]

One option (that results in a smaller object) is to use a C++11 union + an enum
tag, which will make the checks on 85-86 simpler (and make it more obvious that
there can only be one type of extra data).

[zhaobin, 2017/03/03 23:56:42]

We tried union. It is a little complicated to construct & destruct objects with
non-trivial constructors with union. base::Optional seems cleaner
(https://codereview.chromium.org/2675033002/diff/200001/chrome/browser/media/r...)

[dcheng, 2017/03/04 01:49:15]

Hmm... it's still preferable here though: with this, it's hard to tell that
they're mutually exclusive. If you object to writing this out, you can union
using ManualConstructor<T> to make it look nicer.

[zhaobin, 2017/03/06 18:31:26]

Done.

+  base::Optional<DialSinkExtraData> dial_data_;
+
+  // Set if sink is Cast sink.
+  base::Optional<CastSinkExtraData> cast_data_;
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_MEDIA_SINK_INTERNAL_H_