Implement Pepper PPB_VideoDecoder interface.

ppapi/proxy/video_decoder_resource.cc

+// Copyright (c) 2012 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.
+
+#include "ppapi/proxy/video_decoder_resource.h"
+
+#include "base/bind.h"
+#include "gpu/command_buffer/client/gles2_cmd_helper.h"
+#include "gpu/command_buffer/client/gles2_implementation.h"
+#include "ipc/ipc_message.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/ppb_opengles2.h"
+#include "ppapi/proxy/plugin_dispatcher.h"
+#include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/proxy/ppb_graphics_3d_proxy.h"
+#include "ppapi/proxy/serialized_handle.h"
+#include "ppapi/proxy/video_decoder_constants.h"
+#include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/ppb_graphics_3d_shared.h"
+#include "ppapi/shared_impl/proxy_lock.h"
+#include "ppapi/shared_impl/resource_tracker.h"
+#include "ppapi/thunk/enter.h"
+
+using ppapi::thunk::EnterResourceNoLock;
+using ppapi::thunk::PPB_Graphics3D_API;
+using ppapi::thunk::PPB_VideoDecoder_API;
+
+namespace ppapi {
+namespace proxy {
+
+VideoDecoderResource::ShmBuffer::ShmBuffer(
+    scoped_ptr<base::SharedMemory> shm_ptr,
+    uint32_t size,
+    uint32_t shm_id)
+    : shm(shm_ptr.Pass()), addr(NULL), shm_id(shm_id) {
+  if (shm->Map(size))
+    addr = shm->memory();
+}
+
+VideoDecoderResource::ShmBuffer::~ShmBuffer() {
+}
+
+VideoDecoderResource::Texture::Texture(uint32_t texture_target,
+                                       const PP_Size& size)
+    : texture_target(texture_target), size(size) {
+}
+
+VideoDecoderResource::Texture::~Texture() {
+}
+
+VideoDecoderResource::Picture::Picture(int32_t decode_id, uint32_t texture_id)
+    : decode_id(decode_id), texture_id(texture_id) {
+}
+
+VideoDecoderResource::Picture::~Picture() {
+}
+
+VideoDecoderResource::VideoDecoderResource(Connection connection,
+                                           PP_Instance instance)
+    : PluginResource(connection, instance),
+      num_decodes_(0),
+      get_picture_(NULL),
+      gles2_impl_(NULL),
+      initialized_(false),
+      testing_(false),
+      // Set |decoder_last_error_| to PP_OK after successful initialization.
+      // This makes error checking a little more concise, since we can check
+      // that the decoder has been initialized and hasn't returned an error by
+      // just testing |decoder_last_error_|.
+      decoder_last_error_(PP_ERROR_FAILED) {
+  // Clear the decode_ids_ array.
+  memset(decode_ids_, 0, arraysize(decode_ids_));
+  SendCreate(RENDERER, PpapiHostMsg_VideoDecoder_Create());
+}
+
+VideoDecoderResource::~VideoDecoderResource() {
+  // Destroy any textures which haven't been dismissed.
+  TextureMap::iterator it = textures_.begin();
+  for (; it != textures_.end(); ++it)
+    DeleteGLTexture(it->first);
+}
+
+PPB_VideoDecoder_API* VideoDecoderResource::AsPPB_VideoDecoder_API() {
+  return this;
+}
+
+int32_t VideoDecoderResource::Initialize(
+    PP_Resource graphics_context,
+    PP_VideoProfile profile,
+    PP_Bool allow_software_fallback,
+    scoped_refptr<TrackedCallback> callback) {
+  if (initialized_)
+    return PP_ERROR_FAILED;
+  if (profile < 0 || profile > PP_VIDEOPROFILE_MAX)
+    return PP_ERROR_BADARGUMENT;
+  if (initialize_callback_)
+    return PP_ERROR_INPROGRESS;
+  if (!graphics_context)
+    return PP_ERROR_BADRESOURCE;
+
+  // Create a new Graphics3D resource that can create texture resources to share

[Ami GONE FROM CHROMIUM, 2014/05/28 20:50:56]

comment belongs at l.114 instead?

[bbudge, 2014/05/29 00:03:34]

All of this code is just to create that Graphics3D resource. I intended the
comment to describe all of this.

I can move this preliminary code inside the 'if (testing_)' statement though.

+  // with the plugin. We can't use the plugin's Graphics3D, since we create
+  // textures on a proxy thread, and would interfere with the plugin.
+  thunk::EnterResourceCreationNoLock enter_create(pp_instance());
+  if (enter_create.failed())
+    return PP_ERROR_FAILED;
+  int32_t attrib_list[] = {PP_GRAPHICS3DATTRIB_NONE};
+  HostResource host_resource;
+  if (!testing_) {
+    graphics3d_ =
+        ScopedPPResource(ScopedPPResource::PassRef(),
+                         enter_create.functions()->CreateGraphics3D(
+                             pp_instance(), graphics_context, attrib_list));
+    EnterResourceNoLock<PPB_Graphics3D_API> enter_graphics(graphics3d_.get(),
+                                                           true);
+    if (enter_graphics.failed())
+      return PP_ERROR_BADRESOURCE;
+
+    PPB_Graphics3D_Shared* ppb_graphics3d_shared =
+        static_cast<PPB_Graphics3D_Shared*>(enter_graphics.object());
+    gles2_impl_ = ppb_graphics3d_shared->gles2_impl();
+    host_resource = ppb_graphics3d_shared->host_resource();

[Ami GONE FROM CHROMIUM, 2014/05/28 20:50:56]

IDK how "enter" things work in ppapi but they _look_ like scoped objects so it
seems strange to take pointers out of them and persist them outside their scope.
 I trust you/your reviewers know what's going on here...

[bbudge, 2014/05/29 00:03:34]

The pointer will be valid as long as we hold the resource, which we do in
graphics3d_. It is hard to follow.

+  }
+
+  initialize_callback_ = callback;
+
+  Call<PpapiPluginMsg_VideoDecoder_InitializeReply>(
+      RENDERER,
+      PpapiHostMsg_VideoDecoder_Initialize(
+          host_resource, profile, PP_ToBool(allow_software_fallback)),
+      base::Bind(&VideoDecoderResource::OnPluginMsgInitializeComplete, this));
+
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t VideoDecoderResource::Decode(uint32_t decode_id,
+                                     uint32_t size,
+                                     const void* buffer,
+                                     scoped_refptr<TrackedCallback> callback) {
+  if (decoder_last_error_)
+    return decoder_last_error_;
+  if (flush_callback_ || reset_callback_)
+    return PP_ERROR_FAILED;
+  if (decode_callback_)
+    return PP_ERROR_INPROGRESS;
+  if (size > kMaximumBitstreamBufferSize)
+    return PP_ERROR_NOMEMORY;
+
+  // If we allow the plugin to call Decode again, we must have somewhere to
+  // copy their buffer.
+  DCHECK(!available_shm_buffers_.empty() ||
+         shm_buffers_.size() < kMaximumPendingDecodes);
+
+  // Save decode_id in a ring buffer. The ring buffer is sized to store
+  // decode_id for the maximum picture delay.
+  decode_ids_[num_decodes_ % kMaximumPictureDelay] = decode_id;
+  num_decodes_++;
+
+  if (available_shm_buffers_.empty() ||
+      available_shm_buffers_.back()->shm->mapped_size() < size) {
+    uint32_t shm_id;
+    if (shm_buffers_.size() < kMaximumPendingDecodes) {
+      // Signal the host to create a new shm buffer by passing an index outside
+      // the legal range.
+      shm_id = static_cast<uint32_t>(shm_buffers_.size());
+    } else {
+      // Signal the host to grow a buffer by passing a legal index. Choose the
+      // last available shm buffer for simplicity.
+      shm_id = available_shm_buffers_.back()->shm_id;
+      available_shm_buffers_.pop_back();
+    }
+
+    // Synchronously get shared memory. Use GenericSyncCall so we can get the
+    // reply params, which contain the handle.
+    uint32_t shm_size = 0;
+    IPC::Message reply;
+    ResourceMessageReplyParams reply_params;
+    int32_t result =
+        GenericSyncCall(RENDERER,
+                        PpapiHostMsg_VideoDecoder_GetShm(shm_id, size),
+                        &reply,
+                        &reply_params);
+    if (result != PP_OK)
+      return PP_ERROR_FAILED;
+    if (!UnpackMessage<PpapiPluginMsg_VideoDecoder_GetShmReply>(reply,
+                                                                &shm_size))
+      return PP_ERROR_FAILED;
+    base::SharedMemoryHandle shm_handle = base::SharedMemory::NULLHandle();
+    if (!reply_params.TakeSharedMemoryHandleAtIndex(0, &shm_handle))
+      return PP_ERROR_NOMEMORY;
+    scoped_ptr<base::SharedMemory> shm(
+        new base::SharedMemory(shm_handle, false /* read_only */));
+    scoped_ptr<ShmBuffer> shm_buffer(
+        new ShmBuffer(shm.Pass(), shm_size, shm_id));
+    if (!shm_buffer->addr)
+      return PP_ERROR_NOMEMORY;
+
+    available_shm_buffers_.push_back(shm_buffer.get());
+    if (shm_buffers_.size() < kMaximumPendingDecodes) {
+      shm_buffers_.push_back(shm_buffer.release());
+    } else {
+      // Delete manually since ScopedVector won't delete the existing element if
+      // we just assign it.
+      delete shm_buffers_[shm_id];
+      shm_buffers_[shm_id] = shm_buffer.release();
+    }
+  }
+
+  // At this point we should have shared memory to hold the plugin's buffer.
+  DCHECK(!available_shm_buffers_.empty() &&
+         available_shm_buffers_.back()->shm->mapped_size() >= size);
+
+  ShmBuffer* shm_buffer = available_shm_buffers_.back();
+  available_shm_buffers_.pop_back();
+  memcpy(shm_buffer->addr, buffer, size);
+
+  Call<PpapiPluginMsg_VideoDecoder_DecodeReply>(
+      RENDERER,
+      PpapiHostMsg_VideoDecoder_Decode(shm_buffer->shm_id, size),
+      base::Bind(&VideoDecoderResource::OnPluginMsgDecodeComplete, this));
+
+  // If we have another free buffer, or we can still create new buffers, let
+  // the plugin call Decode again.
+  if (!available_shm_buffers_.empty() ||
+      shm_buffers_.size() < kMaximumPendingDecodes)
+    return PP_OK;
+
+  // All buffers are busy and we can't create more. Delay completion until a
+  // buffer is available.
+  decode_callback_ = callback;
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t VideoDecoderResource::GetPicture(
+    PP_VideoPicture* picture,
+    scoped_refptr<TrackedCallback> callback) {
+  if (decoder_last_error_)
+    return decoder_last_error_;
+  if (reset_callback_)
+    return PP_ERROR_FAILED;
+  if (get_picture_callback_)
+    return PP_ERROR_INPROGRESS;
+
+  // If the next picture is ready, return it synchronously.
+  if (!received_pictures_.empty()) {
+    WriteNextPicture(picture);
+    return PP_OK;
+  }
+
+  get_picture_callback_ = callback;
+  get_picture_ = picture;
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void VideoDecoderResource::RecyclePicture(const PP_VideoPicture* picture) {
+  if (decoder_last_error_)
+    return;
+  if (reset_callback_)
+    return;
+
+  Post(RENDERER, PpapiHostMsg_VideoDecoder_RecyclePicture(picture->texture_id));
+}
+
+int32_t VideoDecoderResource::Flush(scoped_refptr<TrackedCallback> callback) {
+  if (decoder_last_error_)
+    return decoder_last_error_;
+  if (reset_callback_)
+    return PP_ERROR_FAILED;
+  if (flush_callback_)
+    return PP_ERROR_INPROGRESS;
+  flush_callback_ = callback;
+
+  Call<PpapiPluginMsg_VideoDecoder_FlushReply>(
+      RENDERER,
+      PpapiHostMsg_VideoDecoder_Flush(),
+      base::Bind(&VideoDecoderResource::OnPluginMsgFlushComplete, this));
+
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t VideoDecoderResource::Reset(scoped_refptr<TrackedCallback> callback) {
+  if (decoder_last_error_)
+    return decoder_last_error_;
+  if (flush_callback_)
+    return PP_ERROR_FAILED;
+  if (reset_callback_)
+    return PP_ERROR_INPROGRESS;
+  reset_callback_ = callback;
+
+  // Cause any pending Decode or GetPicture callbacks to abort after we return,
+  // to avoid reentering the plugin.
+  if (TrackedCallback::IsPending(decode_callback_))
+    decode_callback_->PostAbort();
+  decode_callback_ = NULL;
+  if (TrackedCallback::IsPending(get_picture_callback_))
+    get_picture_callback_->PostAbort();
+  get_picture_callback_ = NULL;
+  Call<PpapiPluginMsg_VideoDecoder_ResetReply>(
+      RENDERER,
+      PpapiHostMsg_VideoDecoder_Reset(),
+      base::Bind(&VideoDecoderResource::OnPluginMsgResetComplete, this));
+
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void VideoDecoderResource::OnReplyReceived(
+    const ResourceMessageReplyParams& params,
+    const IPC::Message& msg) {
+  PPAPI_BEGIN_MESSAGE_MAP(VideoDecoderResource, msg)
+    PPAPI_DISPATCH_PLUGIN_RESOURCE_CALL(
+        PpapiPluginMsg_VideoDecoder_RequestTextures, OnPluginMsgRequestTextures)
+    PPAPI_DISPATCH_PLUGIN_RESOURCE_CALL(
+        PpapiPluginMsg_VideoDecoder_PictureReady, OnPluginMsgPictureReady)
+    PPAPI_DISPATCH_PLUGIN_RESOURCE_CALL(
+        PpapiPluginMsg_VideoDecoder_DismissPicture, OnPluginMsgDismissPicture)
+    PPAPI_DISPATCH_PLUGIN_RESOURCE_CALL(
+        PpapiPluginMsg_VideoDecoder_NotifyError, OnPluginMsgNotifyError)
+    PPAPI_DISPATCH_PLUGIN_RESOURCE_CALL_UNHANDLED(
+        PluginResource::OnReplyReceived(params, msg))
+  PPAPI_END_MESSAGE_MAP()
+}
+
+void VideoDecoderResource::SetForTest() {
+  testing_ = true;
+}
+
+void VideoDecoderResource::OnPluginMsgRequestTextures(
+    const ResourceMessageReplyParams& params,
+    uint32_t num_textures,
+    const PP_Size& size,
+    uint32_t texture_target) {
+  DCHECK(num_textures);
+  std::vector<uint32_t> texture_ids(num_textures);
+  if (gles2_impl_) {
+    gles2_impl_->GenTextures(num_textures, &texture_ids.front());
+    for (uint32_t i = 0; i < num_textures; ++i) {
+      gles2_impl_->ActiveTexture(GL_TEXTURE0);
+      gles2_impl_->BindTexture(texture_target, texture_ids[i]);
+      gles2_impl_->TexParameteri(
+          texture_target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+      gles2_impl_->TexParameteri(
+          texture_target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+      gles2_impl_->TexParameterf(
+          texture_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+      gles2_impl_->TexParameterf(
+          texture_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+      if (texture_target == GL_TEXTURE_2D) {
+        gles2_impl_->TexImage2D(texture_target,
+                                0,
+                                GL_RGBA,
+                                size.width,
+                                size.height,
+                                0,
+                                GL_RGBA,
+                                GL_UNSIGNED_BYTE,
+                                NULL);
+      }
+
+      textures_.insert(
+          std::make_pair(texture_ids[i], Texture(texture_target, size)));
+    }
+    gles2_impl_->Flush();
+  } else if (testing_) {
+    // Create some fake texture ids so we can test picture handling.
+    for (uint32_t i = 0; i < num_textures; ++i) {
+      texture_ids[i] = i + 1;
+      textures_.insert(
+          std::make_pair(texture_ids[i], Texture(texture_target, size)));
+    }
+  }

[Ami GONE FROM CHROMIUM, 2014/05/28 20:50:56]

else NOTREACHED?

[bbudge, 2014/05/29 00:03:34]

What if I DCHECK in the else clause (and remove the 'if (testing_)' ?

+
+  Post(RENDERER, PpapiHostMsg_VideoDecoder_AssignTextures(size, texture_ids));
+}
+
+void VideoDecoderResource::OnPluginMsgPictureReady(
+    const ResourceMessageReplyParams& params,
+    uint32_t decode_id,
+    uint32_t texture_id) {
+  received_pictures_.push(Picture(decode_id, texture_id));
+  // Prepare to accept another call to GetPicture in the callback.
+  scoped_refptr<TrackedCallback> callback;
+  callback.swap(get_picture_callback_);
+  PP_VideoPicture* picture = get_picture_;
+  get_picture_ = NULL;
+  if (TrackedCallback::IsPending(callback)) {

[Ami GONE FROM CHROMIUM, 2014/05/28 20:50:56]

so it's ok to call have pictures become ready without a pending get_picture
callback, and you just drop the frame on the floor?

(might be ok, just want to make sure it's an explicit choice; most video
decoders would accumulate instead).

[bbudge, 2014/05/29 00:03:34]

Good catch! My intention is definitely to queue up pictures when the plugin
can't keep up. The queue length is always bounded since there are a fixed number
of textures available.

Fixed.

+    WriteNextPicture(picture);
+    callback->Run(PP_OK);
+  }
+}
+
+void VideoDecoderResource::OnPluginMsgDismissPicture(
+    const ResourceMessageReplyParams& params,
+    uint32_t texture_id) {
+  DeleteGLTexture(texture_id);
+  textures_.erase(texture_id);
+}
+
+void VideoDecoderResource::OnPluginMsgNotifyError(
+    const ResourceMessageReplyParams& params,
+    int32_t error) {
+  decoder_last_error_ = error;
+  // Cause any pending callbacks to run immediately. Reentrancy isn't a problem,
+  // since the plugin wasn't calling us.
+  RunCallbackWithError(&initialize_callback_);
+  RunCallbackWithError(&decode_callback_);
+  RunCallbackWithError(&get_picture_callback_);
+  RunCallbackWithError(&flush_callback_);
+  RunCallbackWithError(&reset_callback_);
+}
+
+void VideoDecoderResource::OnPluginMsgInitializeComplete(
+    const ResourceMessageReplyParams& params) {
+  decoder_last_error_ = params.result();
+  if (decoder_last_error_ == PP_OK)
+    initialized_ = true;
+
+  // Let the plugin call Initialize again from its callback in case of failure.
+  scoped_refptr<TrackedCallback> callback;
+  callback.swap(initialize_callback_);
+  callback->Run(decoder_last_error_);
+}
+
+void VideoDecoderResource::OnPluginMsgDecodeComplete(
+    const ResourceMessageReplyParams& params,
+    uint32_t shm_id) {
+  if (shm_id >= shm_buffers_.size()) {
+    NOTREACHED();
+    return;
+  }
+  // Make the shm buffer available.
+  available_shm_buffers_.push_back(shm_buffers_[shm_id]);
+  // If the plugin is waiting, let it call Decode again.
+  if (decode_callback_) {
+    scoped_refptr<TrackedCallback> callback;
+    callback.swap(decode_callback_);
+    callback->Run(PP_OK);
+  }
+}
+
+void VideoDecoderResource::OnPluginMsgFlushComplete(
+    const ResourceMessageReplyParams& params) {
+  // All shm buffers should have been made available by now.
+  DCHECK_EQ(shm_buffers_.size(), available_shm_buffers_.size());
+
+  if (get_picture_callback_) {
+    scoped_refptr<TrackedCallback> callback;
+    callback.swap(get_picture_callback_);
+    callback->Abort();
+  }
+
+  scoped_refptr<TrackedCallback> callback;
+  callback.swap(flush_callback_);
+  callback->Run(params.result());
+}
+
+void VideoDecoderResource::OnPluginMsgResetComplete(
+    const ResourceMessageReplyParams& params) {
+  // All shm buffers should have been made available by now.
+  DCHECK_EQ(shm_buffers_.size(), available_shm_buffers_.size());
+  scoped_refptr<TrackedCallback> callback;
+  callback.swap(reset_callback_);
+  callback->Run(params.result());
+}
+
+void VideoDecoderResource::RunCallbackWithError(
+    scoped_refptr<TrackedCallback>* callback) {
+  if (TrackedCallback::IsPending(*callback)) {
+    scoped_refptr<TrackedCallback> temp;
+    callback->swap(temp);
+    temp->Run(decoder_last_error_);
+  }
+}
+
+void VideoDecoderResource::DeleteGLTexture(uint32_t id) {
+  if (gles2_impl_) {
+    gles2_impl_->DeleteTextures(1, &id);
+    gles2_impl_->Flush();
+  }
+}
+
+void VideoDecoderResource::WriteNextPicture(PP_VideoPicture* pp_picture) {
+  DCHECK(!received_pictures_.empty());
+  Picture& picture = received_pictures_.front();
+  uint32_t texture_id = picture.texture_id;
+  TextureMap::iterator it = textures_.find(texture_id);
+  DCHECK(it != textures_.end());
+  // The resource and host identify decodes by a unique id, |num_decodes_|. Use
+  // this to get the plugin's decode_id value, which we stored in |decode_ids_|.
+  uint32_t decode_id = picture.decode_id % kMaximumPictureDelay;

[Ami GONE FROM CHROMIUM, 2014/05/28 20:50:56]

decode_id_id ?

[bbudge, 2014/05/29 00:03:34]

I skirt the issue by eliminating the local. Done.

+  pp_picture->decode_id = decode_ids_[decode_id];
+  pp_picture->texture_id = texture_id;
+  pp_picture->texture_target = it->second.texture_target;
+  pp_picture->texture_size = it->second.size;
+  received_pictures_.pop();
+}
+
+}  // namespace proxy
+}  // namespace ppapi