Redesign the copresence audio handlers.

components/copresence/mediums/audio/audio_manager_impl.h

+// Copyright 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.
+
+#ifndef COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_MANAGER_IMPL_H_
+#define COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_MANAGER_IMPL_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/cancelable_callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_vector.h"
+#include "components/copresence/mediums/audio/audio_manager.h"
+#include "components/copresence/public/copresence_constants.h"
+#include "components/copresence/timed_map.h"
+
+namespace copresence {
+
+class AudioPlayer;
+class AudioRecorder;
+
+// The AudioManagerImpl class manages the playback and recording of tokens. Once
+// playback or recording is started, it is up to the audio manager to handle
+// the specifics of how this is done. In the future, for example, this class
+// may pause recording and playback to implement carrier sense.
+class AudioManagerImpl final : public AudioManager {
+ public:
+  AudioManagerImpl();
+  ~AudioManagerImpl();
+
+  // AudioManager overrides:
+  void Initialize(const DecodeSamplesCallback& decode_cb,
+                  const EncodeTokenCallback& encode_cb) override;
+  void StartPlaying(AudioType type) override;
+  void StopPlaying(AudioType type) override;
+  void StartRecording(AudioType type) override;
+  void StopRecording(AudioType type) override;
+  void SetToken(AudioType type, const std::string& url_unsafe_token) override;
+  const std::string GetToken(AudioType type) override;
+  bool IsRecording(AudioType type) override;
+  bool IsPlaying(AudioType type) override;
+
+  void set_player_for_testing(AudioType type, AudioPlayer* player) {
+    player_[type] = player;
+  }
+  void set_recorder_for_testing(AudioRecorder* recorder) {
+    recorder_ = recorder;
+  }
+
+ private:
+  typedef TimedMap<std::string, scoped_refptr<media::AudioBusRefCounted>>
+      SamplesMap;
+
+  // This is the method that the whispernet client needs to call to return
+  // samples to us.
+  void OnTokenEncoded(const std::string& token,
+                      AudioType type,
+                      const scoped_refptr<media::AudioBusRefCounted>& samples);
+
+  // Update our currently playing token with the new token. Change the playing
+  // samples if needed. Prerequisite: Samples corresponding to this token
+  // should already be in the samples cache.
+  void UpdateToken(AudioType type, const std::string& token);
+
+  // Connector callback to forward the audio samples to Whispernet, based on
+  // the type of recording we've been instructed to do.
+  void DecodeSamplesConnector(const std::string& samples);
+
+  // Callbacks to speak with whispernet.
+  DecodeSamplesCallback decode_cb_;
+  EncodeTokenCallback encode_cb_;
+
+  // This cancelable callback is passed to the recorder. The recorder's
+  // destruction will happen on the audio thread, so it can outlive us.
+  base::CancelableCallback<void(const std::string&)> decode_cancelable_cb_;
+
+  // We use the AudioType enum to index into all our data structures that work
+  // on values for both audible and inaudible.
+  static_assert(AUDIBLE == 0, "AudioType::AUDIBLE should be 0.");
+  static_assert(INAUDIBLE == 1, "AudioType::INAUDIBLE should be 1.");
+
+  // Indexed using enum AudioType.
+  bool playing_[2];
+  bool recording_[2];
+
+  // AudioPlayer and AudioRecorder objects are self-deleting. When we call
+  // Finalize on them, they clean themselves up on the Audio thread.
+  // Indexed using enum AudioType.
+  AudioPlayer* player_[2];
+  AudioRecorder* recorder_;
+
+  // Indexed using enum AudioType.
+  std::string token_[2];
+
+  // Cache that holds the encoded samples. After reaching its limit, the cache
+  // expires the oldest samples first.
+  // Indexed using enum AudioType.
+  ScopedVector<SamplesMap> samples_cache_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioManagerImpl);
+};
+
+}  // namespace copresence
+
+#endif  // COMPONENTS_COPRESENCE_MEDIUMS_AUDIO_AUDIO_MANAGER_IMPL_H_