Motown: Framework parts for mojo transport (producer/consumer/mediapipe) and control (audiotrack).

services/media/framework_mojo/mojo_pull_mode_producer.h

+// 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_MOJO_MOJO_PULL_MODE_PRODUCER_H_
+#define SERVICES_MEDIA_FRAMEWORK_MOJO_MOJO_PULL_MODE_PRODUCER_H_
+
+#include <deque>
+
+#include "base/synchronization/lock.h"
+#include "mojo/common/binding_set.h"
+#include "mojo/services/media/common/interfaces/media_state.mojom.h"
+#include "mojo/services/media/common/interfaces/media_transport.mojom.h"
+#include "services/media/framework/models/active_sink.h"
+#include "services/media/framework_mojo/mojo_allocator.h"
+
+namespace mojo {
+namespace media {
+
+// Implements MediaPullModeProducer to forward a stream across mojo.
+class MojoPullModeProducer :
+    public MediaPullModeProducer,
+    public ActiveSink {
+ public:
+  static std::shared_ptr<MojoPullModeProducer> Create() {
+    return std::shared_ptr<MojoPullModeProducer>(new MojoPullModeProducer());
+  }
+
+  ~MojoPullModeProducer() override;
+
+  // Adds a binding.
+  void AddBinding(InterfaceRequest<MediaPullModeProducer> producer);
+
+  // MediaPullModeProducer implementation.
+  void GetBuffer(const GetBufferCallback& callback) override;
+
+  void PullPacket(
+      MediaPacketPtr to_release,
+      const PullPacketCallback& callback) override;
+
+  void ReleasePacket(MediaPacketPtr to_release) override;
+
+  // ActiveSink implementation.
+  PayloadAllocator* allocator() override;
+
+  void SetDemandCallback(const DemandCallback& demand_callback) override;
+
+  void Prime() override;
+
+  Demand SupplyPacket(PacketPtr packet) override;
+
+ private:
+  MojoPullModeProducer();
+
+  // Handles as many pending pulls as possible.
+  // MUST BE CALLED WITH lock_ TAKEN.
+  void HandlePendingPullsUnsafe();
+
+  // Attempts to handle a pull and indicates whether it was handled.
+  // MUST BE CALLED WITH lock_ TAKEN.
+  bool MaybeHandlePullUnsafe(const PullPacketCallback& callback);
+
+  // Runs the callback with a new MediaPacket created from the given Packet.
+  // MUST BE CALLED WITH lock_ TAKEN.
+  void HandlePullWithPacketUnsafe(
+      const PullPacketCallback& callback,
+      PacketPtr packet);
+
+  // Creates a MediaPacket from a Packet.
+  MediaPacketPtr CreateMediaPacket(const PacketPtr& packet);
+
+  BindingSet<MediaPullModeProducer> bindings_;
+
+  DemandCallback demand_callback_;
+
+  // Allocates from the shared buffer.
+  MojoAllocator mojo_allocator_;
+
+  mutable base::Lock lock_;
+  // THE FIELDS BELOW SHOULD ONLY BE ACCESSED WITH lock_ TAKEN.
+  MediaState state_;
+  Demand demand_;
+  int64_t presentation_time_;
+
+  // pending_pulls_ contains the callbacks for the pull requests that have yet
+  // to be satisfied. unreleased_packets_ contains the packets that have been
+  // delivered via pull but have not yet been released. cached_packet_ is a
+  // packet waiting for a pull (we keep one ready so we can be preparing a
+  // packet between pulls). If cached_packet_ isn't nullptr, pending_pulls_
+  // should be empty. We signal positive demand when cached_packet_ is nullptr
+  // and negative demand when it isn't.
+  std::deque<PullPacketCallback> pending_pulls_;
+  std::deque<PacketPtr> unreleased_packets_;
+  PacketPtr cached_packet_;
+  // THE FIELDS ABOVE SHOULD ONLY BE ACCESSED WITH lock_ TAKEN.
+};
+
+}  // namespace media
+}  // namespace mojo
+
+#endif  // SERVICES_MEDIA_FRAMEWORK_MOJO_MOJO_PULL_MODE_PRODUCER_H_