Motown in-proc streaming framework used to implement media services.

services/media/framework/stages/lpcm_stage_input.h

Index: services/media/framework/stages/lpcm_stage_input.h
diff --git a/services/media/framework/stages/lpcm_stage_input.h b/services/media/framework/stages/lpcm_stage_input.h
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+++ b/services/media/framework/stages/lpcm_stage_input.h
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+// Copyright 2016 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 SERVICES_MEDIA_FRAMEWORK_ENGINE_LPCM_STAGE_INPUT_H_
+#define SERVICES_MEDIA_FRAMEWORK_ENGINE_LPCM_STAGE_INPUT_H_
+
+#include <vector>
+
+#include "services/media/framework/lpcm_util.h"
+#include "services/media/framework/models/demand.h"
+#include "services/media/framework/models/lpcm_frame_buffer.h"
+#include "services/media/framework/stages/stage_input.h"
+
+namespace mojo {
+namespace media {
+
+class LpcmStageOutput;
+
+// Represents a stage's connector to an adjacent upstream stage, with LPCM
+// optmizations.
+class LpcmStageInput : public StageInput {
+ public:
+  LpcmStageInput();
+
+  ~LpcmStageInput();
+
+  // Sets the stream type.
+  void set_stream_type(const LpcmStreamType& stream_type);
+
+  // Suggests possible demand frame count, useful when !connected_to_lpcm().
+  void SuggestDemand(uint64_t frame_count, Engine* engine);
+
+  // Updates the demand signalled to the connected upstream output.
+  void SetLpcmDemand(
+      void* buffer,
+      uint64_t frame_count,
+      bool mix,
+      bool synchronous,
+      Engine* engine);
+
+  // Indicates whether demand is pending.
+  bool demand_pending() const {
+    return demand_pending_;
+  }
+
+  // Returns supplied frames.
+  LpcmFrameBuffer& lpcm_supply() {
+    return lpcm_supply_;
+  }
+
+  // Indicates whether we've hit end-of-stream.
+  bool end_of_stream() const {
+    return end_of_stream_;
+  }
+
+  // Indicates the frame count originally demanded.
+  uint64_t demand_frame_count() const {
+    return frame_count_;
+  }
+
+  // StageInput overrides.
+  bool SupplyPacketFromOutput(PacketPtr packet) override;
+
+  LpcmStageInput* get_lpcm() override;
+
+ private:
+  static const uint64_t kDefaultFrameCount = 512;
+
+  bool connected_to_lpcm();
+
+  // Copies or mixes frames from packet_frames_ to demand_frames_. This is only
+  // used when !connected_to_lpcm() and the stage has supplied a buffer. The
+  // return value indicates whether the demand was met.
+  bool CopyOrMixFrames();
+
+  // Ensures demand_buffer_ can accommodate frame_count frames and returns it.
+  void* GetDemandBuffer(uint64_t frame_count);
+
+  bool demand_pending_;
+
+  void* buffer_;
+  uint64_t frame_count_;
+  bool mix_;
+  bool synchronous_;
+
+  LpcmFrameBuffer lpcm_supply_; // Frames supplied to this stage.
+  LpcmFrameBuffer packet_frames_; // Source for packet payload copy/mix.
+  LpcmFrameBuffer demand_frames_; // Destination for packet payload copy/mix.
+
+  bool end_of_stream_;
+
+  std::unique_ptr<LpcmUtil> lpcm_util_;
+  std::vector<uint8_t> demand_buffer_;
+
+  LpcmFrameBuffer::ExhaustedCallback packet_exhausted_function_;
+};
+
+}  // namespace media
+}  // namespace mojo
+
+#endif  // SERVICES_MEDIA_FRAMEWORK_ENGINE_LPCM_STAGE_INPUT_H_