Implement Pepper PPB_VideoDecoder interface.

ppapi/proxy/video_decoder_resource.h

Index: ppapi/proxy/video_decoder_resource.h
diff --git a/ppapi/proxy/video_decoder_resource.h b/ppapi/proxy/video_decoder_resource.h
new file mode 100644
index 0000000000000000000000000000000000000000..82396b0269e45f36e410141326189a948f94c3ca
--- /dev/null
+++ b/ppapi/proxy/video_decoder_resource.h
@@ -0,0 +1,193 @@
+// Copyright (c) 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 PPAPI_PROXY_VIDEO_DECODER_RESOURCE_H_
+#define PPAPI_PROXY_VIDEO_DECODER_RESOURCE_H_
+
+#include <queue>
+
+#include "base/containers/hash_tables.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "ppapi/proxy/connection.h"
+#include "ppapi/proxy/plugin_resource.h"
+#include "ppapi/proxy/ppapi_proxy_export.h"
+#include "ppapi/shared_impl/resource.h"
+#include "ppapi/shared_impl/scoped_pp_resource.h"
+#include "ppapi/thunk/ppb_video_decoder_api.h"
+
+namespace gpu {
+namespace gles2 {
+class GLES2Implementation;
+}
+}
+
+namespace ppapi {
+
+class PPB_Graphics3D_Shared;
+class TrackedCallback;
+
+namespace proxy {
+
+class PPAPI_PROXY_EXPORT VideoDecoderResource
+    : public PluginResource,
+      public thunk::PPB_VideoDecoder_API {
+ public:
+  VideoDecoderResource(Connection connection, PP_Instance instance);
+  virtual ~VideoDecoderResource();
+
+  // Resource overrides.
+  virtual thunk::PPB_VideoDecoder_API* AsPPB_VideoDecoder_API() OVERRIDE;
+
+  // PPB_VideoDecoder_API implementation.
+  virtual int32_t Initialize(PP_Resource graphics_context,
+                             PP_VideoProfile profile,
+                             PP_Bool allow_software_fallback,
+                             scoped_refptr<TrackedCallback> callback) OVERRIDE;
+  virtual int32_t Decode(uint32_t decode_id,
+                         uint32_t size,
+                         const void* buffer,
+                         scoped_refptr<TrackedCallback> callback) OVERRIDE;
+  virtual int32_t GetPicture(PP_VideoPicture* picture,
+                             scoped_refptr<TrackedCallback> callback) OVERRIDE;
+  virtual void RecyclePicture(const PP_VideoPicture* picture) OVERRIDE;
+  virtual int32_t Flush(scoped_refptr<TrackedCallback> callback) OVERRIDE;
+  virtual int32_t Reset(scoped_refptr<TrackedCallback> callback) OVERRIDE;
+
+  // PluginResource implementation.
+  virtual void OnReplyReceived(const ResourceMessageReplyParams& params,
+                               const IPC::Message& msg) OVERRIDE;
+
+  // Called only by unit tests. This bypasses Graphics3D setup, which doesn't
+  // work in ppapi::proxy::PluginProxyTest.
+  void SetForTest();
+
+ private:
+  // Struct to hold a shared memory buffer.
+  struct ShmBuffer {
+    ShmBuffer(scoped_ptr<base::SharedMemory> shm,
+              uint32_t size,
+              uint32_t shm_id);
+    ~ShmBuffer();
+
+    scoped_ptr<base::SharedMemory> shm;
+    uint32_t size;

[dmichael (off chromium), 2014/05/20 22:40:38]

is this different that SharedMemory::actual_size()? If so, maybe you could
comment what it means (size of the decode buffer, while the shared memory region
might be larger?)

[bbudge, 2014/05/22 18:34:55]

This is just shm->mapped_size().
Removed the extra field.

+    void* addr;
+    // Index into shm_buffers_ vector, used as an id. This should map 1:1 to
+    // the index on the host side of the proxy.
+    uint32_t shm_id;
+  };
+
+  // Struct to hold texture information.
+  struct Texture {
+    Texture(uint32_t texture_target, const PP_Size& size);
+    ~Texture();
+
+    uint32_t texture_target;
+    PP_Size size;
+  };
+
+  // Struct to hold a picture received from the decoder.
+  struct Picture {
+    Picture(int32_t decode_id, uint32_t texture_id);
+    ~Picture();
+
+    uint32_t decode_id;
+    uint32_t texture_id;
+  };
+
+  int32_t InitializeInternal(PP_Resource graphics_context,
+                             PP_VideoProfile profile,
+                             PP_Bool allow_software_fallback,
+                             scoped_refptr<TrackedCallback> callback,
+                             bool testing);
+
+  // Unsolicited reply message handlers.
+  void OnPluginMsgRequestTextures(const ResourceMessageReplyParams& params,
+                                  uint32_t num_textures,
+                                  const PP_Size& size,
+                                  uint32_t texture_target);
+  void OnPluginMsgPictureReady(const ResourceMessageReplyParams& params,
+                               uint32_t decode_id,
+                               uint32_t texture_id);
+  void OnPluginMsgDismissPicture(const ResourceMessageReplyParams& params,
+                                 uint32_t texture_id);
+  void OnPluginMsgNotifyError(const ResourceMessageReplyParams& params,
+                              int32_t error);
+
+  // Reply message handlers for operations that are done in the host.
+  void OnPluginMsgInitializeComplete(const ResourceMessageReplyParams& params);
+  void OnPluginMsgGetShmComplete(const ResourceMessageReplyParams& params,
+                                 uint32_t size);
+  void OnPluginMsgDecodeComplete(const ResourceMessageReplyParams& params,
+                                 uint32_t shm_id);
+  void OnPluginMsgFlushComplete(const ResourceMessageReplyParams& params);
+  void OnPluginMsgResetComplete(const ResourceMessageReplyParams& params);
+
+  int32_t TryDecode(uint32_t size,
+                    const void* buffer,
+                    scoped_refptr<TrackedCallback> callback);
+  void SendDecodeMessage(uint32_t shm_id);
+  void RunDecodeCallback(int32_t result);
+
+  void DeleteGLTexture(uint32_t texture_id);
+  void WriteNextPicture(PP_VideoPicture* picture);
+
+  // ScopedVector to own the shared memory buffers.
+  ScopedVector<ShmBuffer> shm_buffers_;
+
+  // List of available shared memory buffers.
+  typedef std::vector<ShmBuffer*> ShmBufferList;
+  ShmBufferList available_shm_buffers_;
+
+  // Map of GL texture id to texture info.
+  typedef base::hash_map<uint32_t, Texture> TextureMap;
+  TextureMap textures_;
+
+  // Queue of received pictures.
+  typedef std::queue<Picture> PictureQueue;
+  PictureQueue received_pictures_;
+
+  // Pending callbacks.
+  scoped_refptr<TrackedCallback> initialize_callback_;
+  scoped_refptr<TrackedCallback> decode_callback_;
+  scoped_refptr<TrackedCallback> get_picture_callback_;
+  scoped_refptr<TrackedCallback> flush_callback_;
+  scoped_refptr<TrackedCallback> reset_callback_;
+
+  // The maximum delay (in Decode calls) before we receive a picture. If we
+  // haven't received a picture from a Decode call after this many successive
+  // calls to Decode, then we will never receive a picture from the call.
+  // Note that this isn't guaranteed by H264 or other codecs. In practice, this
+  // number is less than 16. We make it much larger since the cost of tracking
+  // this is low.
+  static const int kMaximumPictureLatency = 128;

[dmichael (off chromium), 2014/05/20 22:40:38]

nit: I'm used to Latency meaning time. Maybe there's a better name, like... 
kMaximumPictureBacklog?

And do you actually need this? I would have assumed that the delay would be
effectively bounded by...
const uint32_t kMaximumPendingDecodes = 8;

[bbudge, 2014/05/22 18:34:55]

Renamed to kMaximumPictureDelay. Unfortunately for us, this is a property of the
stream, not of number of simultaneous decodes. The software decoder (FFmpeg)
only supports 16 buffers of delay. This constant matches what is done elsewhere
in Chrome, picking a large value because it's not expensive and should work,
even with pathological cases.

+  // Counter modulo kMaximumPictureLatency to generate decode ids.
+  uint32_t next_decode_id_;
+  uint32_t decode_ids_[kMaximumPictureLatency];
+
+  // State for pending decode_callback_.
+  scoped_ptr<char[]> temp_buffer_;

[dmichael (off chromium), 2014/05/20 22:40:38]

scoped_ptr<uint8_t[]>?

[bbudge, 2014/05/22 18:34:55]

Done.

+  uint32_t decode_size_;
+  const void* decode_buffer_;
+  bool get_shm_buffer_pending_;
+  uint32_t pending_shm_id_;
+  // State for pending get_picture_callback_.
+  PP_VideoPicture* get_picture_;
+
+  ScopedPPResource graphics3d_;
+  gpu::gles2::GLES2Implementation* gles2_impl_;
+
+  bool initialized_;
+  bool testing_;
+  int32_t decoder_last_error_;
+
+  DISALLOW_COPY_AND_ASSIGN(VideoDecoderResource);
+};
+
+}  // namespace proxy
+}  // namespace ppapi
+
+#endif  // PPAPI_PROXY_VIDEO_DECODER_RESOURCE_H_