Allow multiple concurrent Decode() requests in VideoDecoder interface.

media/filters/fake_video_decoder.cc

 // Copyright 2013 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 "media/filters/fake_video_decoder.h"
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "media/base/bind_to_current_loop.h"
 #include "media/base/test_helpers.h"
 
 namespace media {
 
 FakeVideoDecoder::FakeVideoDecoder(int decoding_delay,
-                                   bool supports_get_decode_output)
-    : task_runner_(base::MessageLoopProxy::current()),
-      decoding_delay_(decoding_delay),
+                                   bool supports_get_decode_output,
+                                   int max_parallel_decoding_requests)
+    : decoding_delay_(decoding_delay),
       supports_get_decode_output_(supports_get_decode_output),
-      state_(UNINITIALIZED),
+      max_parallel_decoding_requests_(max_parallel_decoding_requests),
+      state_(STATE_UNINITIALIZED),
+      hold_decode_(false),
       total_bytes_decoded_(0),
       weak_factory_(this) {
   DCHECK_GE(decoding_delay, 0);
 }
 
 FakeVideoDecoder::~FakeVideoDecoder() {
-  DCHECK_EQ(state_, UNINITIALIZED);
+  DCHECK_EQ(state_, STATE_UNINITIALIZED);
 }
 
 void FakeVideoDecoder::Initialize(const VideoDecoderConfig& config,
                                   bool low_delay,
                                   const PipelineStatusCB& status_cb) {
-  DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(config.IsValidConfig());
-  DCHECK(decode_cb_.IsNull()) << "No reinitialization during pending decode.";
+  DCHECK(held_decode_callbacks_.empty())
+      << "No reinitialization during pending decode.";
   DCHECK(reset_cb_.IsNull()) << "No reinitialization during pending reset.";
 
   current_config_ = config;
   init_cb_.SetCallback(BindToCurrentLoop(status_cb));
 
   if (!decoded_frames_.empty()) {
     DVLOG(1) << "Decoded frames dropped during reinitialization.";
     decoded_frames_.clear();
   }
 
-  state_ = NORMAL;
+  state_ = STATE_NORMAL;
   init_cb_.RunOrHold(PIPELINE_OK);
 }
 
 void FakeVideoDecoder::Decode(const scoped_refptr<DecoderBuffer>& buffer,
                               const DecodeCB& decode_cb) {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  DCHECK(decode_cb_.IsNull()) << "Overlapping decodes are not supported.";
+  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(reset_cb_.IsNull());
-  DCHECK_LE(decoded_frames_.size(), static_cast<size_t>(decoding_delay_));
+  DCHECK_LE(decoded_frames_.size(),
+            decoding_delay_ + held_decode_callbacks_.size());
+  DCHECK_LT(static_cast<int>(held_decode_callbacks_.size()),
+            max_parallel_decoding_requests_);
 
   int buffer_size = buffer->end_of_stream() ? 0 : buffer->data_size();
-  decode_cb_.SetCallback(
+  DecodeCB wrapped_decode_cb =
       BindToCurrentLoop(base::Bind(&FakeVideoDecoder::OnFrameDecoded,
                                    weak_factory_.GetWeakPtr(),
                                    buffer_size,
-                                   decode_cb)));
+                                   decode_cb));
 
-  if (buffer->end_of_stream() && decoded_frames_.empty()) {
-    decode_cb_.RunOrHold(kOk, VideoFrame::CreateEOSFrame());
+  if (state_ == STATE_ERROR) {
+    wrapped_decode_cb.Run(kDecodeError, scoped_refptr<VideoFrame>());
     return;
   }
 
-  if (!buffer->end_of_stream()) {
+  if (buffer->end_of_stream()) {
+    state_ = STATE_END_OF_STREAM;
+  } else {
     DCHECK(VerifyFakeVideoBufferForTest(buffer, current_config_));
     scoped_refptr<VideoFrame> video_frame = VideoFrame::CreateColorFrame(
         current_config_.coded_size(), 0, 0, 0, buffer->timestamp());
     decoded_frames_.push_back(video_frame);
-
-    if (decoded_frames_.size() <= static_cast<size_t>(decoding_delay_)) {
-      decode_cb_.RunOrHold(kNotEnoughData, scoped_refptr<VideoFrame>());
-      return;
-    }
   }
 
-  scoped_refptr<VideoFrame> frame = decoded_frames_.front();
-  decoded_frames_.pop_front();
-  decode_cb_.RunOrHold(kOk, frame);
+  RunOrHoldDecode(wrapped_decode_cb);
 }
 
 void FakeVideoDecoder::Reset(const base::Closure& closure) {
-  DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(reset_cb_.IsNull());
+
   reset_cb_.SetCallback(BindToCurrentLoop(closure));
+  decoded_frames_.clear();
 
   // Defer the reset if a decode is pending.
-  if (!decode_cb_.IsNull())
+  if (!held_decode_callbacks_.empty())
     return;
 
   DoReset();
 }
 
 void FakeVideoDecoder::Stop() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(thread_checker_.CalledOnValidThread());
 
   if (!init_cb_.IsNull())
     SatisfyInit();
-  if (!decode_cb_.IsNull())
+  if (!held_decode_callbacks_.empty())
     SatisfyDecode();
   if (!reset_cb_.IsNull())
     SatisfyReset();
 
   decoded_frames_.clear();
-  state_ = UNINITIALIZED;
+  state_ = STATE_UNINITIALIZED;
 }
 
 scoped_refptr<VideoFrame> FakeVideoDecoder::GetDecodeOutput() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(thread_checker_.CalledOnValidThread());
   if (!supports_get_decode_output_ || decoded_frames_.empty())
     return NULL;
   scoped_refptr<VideoFrame> out = decoded_frames_.front();
   decoded_frames_.pop_front();
   return out;
 }
 
 void FakeVideoDecoder::HoldNextInit() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(thread_checker_.CalledOnValidThread());
   init_cb_.HoldCallback();
 }
 
-void FakeVideoDecoder::HoldNextDecode() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  decode_cb_.HoldCallback();
+void FakeVideoDecoder::HoldDecode() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  hold_decode_ = true;
 }
 
 void FakeVideoDecoder::HoldNextReset() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
+  DCHECK(thread_checker_.CalledOnValidThread());
   reset_cb_.HoldCallback();
 }
 
 void FakeVideoDecoder::SatisfyInit() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  DCHECK(decode_cb_.IsNull());
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(held_decode_callbacks_.empty());
   DCHECK(reset_cb_.IsNull());
 
   init_cb_.RunHeldCallback();
 }
 
 void FakeVideoDecoder::SatisfyDecode() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  decode_cb_.RunHeldCallback();
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(hold_decode_);
 
-  if (!reset_cb_.IsNull())
+  hold_decode_ = false;
+
+  while (!held_decode_callbacks_.empty()) {
+    SatisfySingleDecode();
+  }
+}
+
+void FakeVideoDecoder::SatisfySingleDecode() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!held_decode_callbacks_.empty());
+
+  DecodeCB decode_cb = held_decode_callbacks_.front();
+  held_decode_callbacks_.pop_front();
+  RunDecodeCallback(decode_cb);
+
+  if (!reset_cb_.IsNull() && held_decode_callbacks_.empty())
     DoReset();
 }
 
 void FakeVideoDecoder::SatisfyReset() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  DCHECK(decode_cb_.IsNull());
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(held_decode_callbacks_.empty());
   reset_cb_.RunHeldCallback();
 }
 
-void FakeVideoDecoder::DoReset() {
-  DCHECK(task_runner_->BelongsToCurrentThread());
-  DCHECK(decode_cb_.IsNull());
-  DCHECK(!reset_cb_.IsNull());
+void FakeVideoDecoder::SimulateError() {
+  DCHECK(thread_checker_.CalledOnValidThread());
 
+  state_ = STATE_ERROR;
+  while (!held_decode_callbacks_.empty()) {
+    held_decode_callbacks_.front().Run(kDecodeError,
+                                       scoped_refptr<VideoFrame>());
+    held_decode_callbacks_.pop_front();
+  }
   decoded_frames_.clear();
-  reset_cb_.RunOrHold();
+}
+
+int FakeVideoDecoder::GetMaxDecodeRequests() const {
+  return max_parallel_decoding_requests_;
 }
 
 void FakeVideoDecoder::OnFrameDecoded(
     int buffer_size,
     const DecodeCB& decode_cb,
     Status status,
     const scoped_refptr<VideoFrame>& video_frame) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
   if (status == kOk || status == kNotEnoughData)
     total_bytes_decoded_ += buffer_size;
   decode_cb.Run(status, video_frame);
 }
 
+void FakeVideoDecoder::RunOrHoldDecode(const DecodeCB& decode_cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (hold_decode_) {
+    held_decode_callbacks_.push_back(decode_cb);
+  } else {
+    DCHECK(held_decode_callbacks_.empty());
+    RunDecodeCallback(decode_cb);
+  }
+}
+
+void FakeVideoDecoder::RunDecodeCallback(const DecodeCB& decode_cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (!reset_cb_.IsNull()) {
+    DCHECK(decoded_frames_.empty());
+    decode_cb.Run(kAborted, scoped_refptr<VideoFrame>());
+    return;
+  }
+
+  // Make sure we leave decoding_delay_ frames in the queue and also frames for
+  // all pending decode callbacks, except the current one.
+  if (decoded_frames_.size() <=
+          decoding_delay_ + held_decode_callbacks_.size() &&
+      state_ != STATE_END_OF_STREAM) {
+    decode_cb.Run(kNotEnoughData, scoped_refptr<VideoFrame>());
+    return;
+  }
+
+  scoped_refptr<VideoFrame> frame;
+  if (decoded_frames_.empty()) {
+    DCHECK_EQ(state_, STATE_END_OF_STREAM);
+    frame = VideoFrame::CreateEOSFrame();
+  } else {
+    frame = decoded_frames_.front();
+    decoded_frames_.pop_front();
+  }
+  decode_cb.Run(kOk, frame);
+}
+
+void FakeVideoDecoder::DoReset() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(held_decode_callbacks_.empty());
+  DCHECK(!reset_cb_.IsNull());
+
+  reset_cb_.RunOrHold();
+}
+
 }  // namespace media