[Mojo Video Capture] Retire buffers when Android Chromium goes to the background

content/browser/renderer_host/media/video_capture_controller.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 "content/browser/renderer_host/media/video_capture_controller.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <map>
@@ skipping 92 matching lines @@
       frame_buffer_pool_(frame_buffer_pool),
       max_consumer_utilization_(
           media::VideoFrameConsumerFeedbackObserver::kNoUtilizationRecorded),
       consumer_hold_count_(0) {}
 
 VideoCaptureController::BufferState::~BufferState() = default;
 
 VideoCaptureController::BufferState::BufferState(
     const VideoCaptureController::BufferState& other) = default;
 
+VideoCaptureController::BufferState& VideoCaptureController::BufferState::
+operator=(const BufferState& other) = default;
+
 void VideoCaptureController::BufferState::RecordConsumerUtilization(
     double utilization) {
   if (std::isfinite(utilization) && utilization >= 0.0) {
     max_consumer_utilization_ =
         std::max(max_consumer_utilization_, utilization);
   }
 }
 
 void VideoCaptureController::BufferState::IncreaseConsumerCount() {
   if (consumer_hold_count_ == 0)
@@ skipping 48 matching lines @@
 base::WeakPtr<VideoCaptureController>
 VideoCaptureController::GetWeakPtrForIOThread() {
   return weak_ptr_factory_.GetWeakPtr();
 }
 
 void VideoCaptureController::SetFrameBufferPool(
     std::unique_ptr<media::FrameBufferPool> frame_buffer_pool) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   frame_buffer_pool_ = std::move(frame_buffer_pool);
   // Update existing BufferState entries.
-  for (auto& entry : buffer_id_to_state_map_)
-    entry.second.SetFrameBufferPool(frame_buffer_pool_.get());
+  for (auto& entry : buffer_states_)
+    entry.SetFrameBufferPool(frame_buffer_pool_.get());
 }
 
 void VideoCaptureController::SetConsumerFeedbackObserver(
     std::unique_ptr<media::VideoFrameConsumerFeedbackObserver>
         consumer_feedback_observer) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   consumer_feedback_observer_ = std::move(consumer_feedback_observer);
   // Update existing BufferState entries.
-  for (auto& entry : buffer_id_to_state_map_)
-    entry.second.SetConsumerFeedbackObserver(consumer_feedback_observer_.get());
+  for (auto& entry : buffer_states_)
+    entry.SetConsumerFeedbackObserver(consumer_feedback_observer_.get());
 }
 
 void VideoCaptureController::AddClient(
     VideoCaptureControllerID id,
     VideoCaptureControllerEventHandler* event_handler,
     media::VideoCaptureSessionId session_id,
     const media::VideoCaptureParams& params) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DVLOG(1) << "VideoCaptureController::AddClient() -- id=" << id
            << ", session_id=" << session_id
@@ skipping 41 matching lines @@
 int VideoCaptureController::RemoveClient(
     VideoCaptureControllerID id,
     VideoCaptureControllerEventHandler* event_handler) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DVLOG(1) << "VideoCaptureController::RemoveClient, id " << id;
 
   ControllerClient* client = FindClient(id, event_handler, controller_clients_);
   if (!client)
     return kInvalidMediaCaptureSessionId;
 
-  // Take back all buffers held by the |client|.
-  for (const auto& buffer_id : client->buffers_in_use)
-    buffer_id_to_state_map_.at(buffer_id).DecreaseConsumerCount();
+  for (const auto& buffer_id : client->buffers_in_use) {
+    OnClientFinishedConsumingBuffer(
+        client, buffer_id,
+        media::VideoFrameConsumerFeedbackObserver::kNoUtilizationRecorded);
+  }
   client->buffers_in_use.clear();
 
   int session_id = client->session_id;
   controller_clients_.remove_if(
       [client](const std::unique_ptr<ControllerClient>& ptr) {
         return ptr.get() == client;
       });
 
   return session_id;
 }
@@ skipping 82 matching lines @@
     NOTREACHED();
     return;
   }
   auto buffers_in_use_entry_iter =
       std::find(std::begin(client->buffers_in_use),
                 std::end(client->buffers_in_use), buffer_id);
   if (buffers_in_use_entry_iter == std::end(client->buffers_in_use)) {
     NOTREACHED();
     return;
   }
+  client->buffers_in_use.erase(buffers_in_use_entry_iter);
 
-  BufferState& buffer_state = buffer_id_to_state_map_.at(buffer_id);
-  buffer_state.RecordConsumerUtilization(consumer_resource_utilization);
-  buffer_state.DecreaseConsumerCount();
-  client->buffers_in_use.erase(buffers_in_use_entry_iter);
+  OnClientFinishedConsumingBuffer(client, buffer_id,
+                                  consumer_resource_utilization);
 }
 
 const media::VideoCaptureFormat&
 VideoCaptureController::GetVideoCaptureFormat() const {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   return video_capture_format_;
 }
 
 void VideoCaptureController::OnIncomingCapturedVideoFrame(
     media::VideoCaptureDevice::Client::Buffer buffer,
     scoped_refptr<VideoFrame> frame) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   const int buffer_id = buffer.id();
   DCHECK_NE(buffer_id, media::VideoCaptureBufferPool::kInvalidId);
-
-  // Insert if not exists.
-  const auto it =
-      buffer_id_to_state_map_
-          .insert(std::make_pair(
-              buffer_id, BufferState(buffer_id, buffer.frame_feedback_id(),
-                                     consumer_feedback_observer_.get(),
-                                     frame_buffer_pool_.get())))
-          .first;
-  BufferState& buffer_state = it->second;
-  DCHECK(buffer_state.HasZeroConsumerHoldCount());
+  auto buffer_state_iter = FindBufferState(buffer_id);
+  if (buffer_state_iter == buffer_states_.end()) {
+    buffer_states_.emplace_back(buffer_id, buffer.frame_feedback_id(),
+                                consumer_feedback_observer_.get(),
+                                frame_buffer_pool_.get());
+    buffer_state_iter = buffer_states_.end() - 1;
+  }
+  DCHECK(buffer_state_iter->HasZeroConsumerHoldCount());
 
   if (state_ == VIDEO_CAPTURE_STATE_STARTED) {
     if (!frame->metadata()->HasKey(VideoFrameMetadata::FRAME_RATE)) {
       frame->metadata()->SetDouble(VideoFrameMetadata::FRAME_RATE,
                                    video_capture_format_.frame_rate);
     }
     std::unique_ptr<base::DictionaryValue> metadata =
         frame->metadata()->CopyInternalValues();
 
     // Only I420 and Y16 pixel formats are currently supported.
@@ skipping 34 matching lines @@
       client->event_handler->OnBufferReady(client->controller_id, buffer_id,
                                            frame);
 
       auto buffers_in_use_entry_iter =
           std::find(std::begin(client->buffers_in_use),
                     std::end(client->buffers_in_use), buffer_id);
       if (buffers_in_use_entry_iter == std::end(client->buffers_in_use))
         client->buffers_in_use.push_back(buffer_id);
       else
         DCHECK(false) << "Unexpected duplicate buffer: " << buffer_id;
-      buffer_state.IncreaseConsumerCount();
+      buffer_state_iter->IncreaseConsumerCount();
     }
   }
 
   if (!has_received_frames_) {
     UMA_HISTOGRAM_COUNTS("Media.VideoCapture.Width",
                          frame->visible_rect().width());
     UMA_HISTOGRAM_COUNTS("Media.VideoCapture.Height",
                          frame->visible_rect().height());
     UMA_HISTOGRAM_ASPECT_RATIO("Media.VideoCapture.AspectRatio",
                                frame->visible_rect().width(),
                                frame->visible_rect().height());
     double frame_rate = 0.0f;
     if (!frame->metadata()->GetDouble(VideoFrameMetadata::FRAME_RATE,
                                       &frame_rate)) {
       frame_rate = video_capture_format_.frame_rate;
     }
     UMA_HISTOGRAM_COUNTS("Media.VideoCapture.FrameRate", frame_rate);
     has_received_frames_ = true;
   }
 }
 
 void VideoCaptureController::OnError() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   state_ = VIDEO_CAPTURE_STATE_ERROR;
 
   for (const auto& client : controller_clients_) {
     if (client->session_closed)
-       continue;
+      continue;
     client->event_handler->OnError(client->controller_id);
   }
 }
 
 void VideoCaptureController::OnLog(const std::string& message) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   MediaStreamManager::SendMessageToNativeLog("Video capture: " + message);
 }
 
-void VideoCaptureController::OnBufferDestroyed(int buffer_id_to_drop) {
+void VideoCaptureController::OnBufferRetired(int buffer_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
-  for (const auto& client : controller_clients_) {
-    if (client->session_closed)
-      continue;
+  auto buffer_state_iter = FindBufferState(buffer_id);
+  DCHECK(buffer_state_iter != buffer_states_.end());
 
-    auto known_buffers_entry_iter =
-        std::find(std::begin(client->known_buffers),
-                  std::end(client->known_buffers), buffer_id_to_drop);
-    if (known_buffers_entry_iter != std::end(client->known_buffers)) {
-      client->known_buffers.erase(known_buffers_entry_iter);
-      client->event_handler->OnBufferDestroyed(client->controller_id,
-                                               buffer_id_to_drop);
-    }
-  }
-
-  buffer_id_to_state_map_.erase(buffer_id_to_drop);
+  // If there are any clients still using the buffer, we need to allow them
+  // to finish up. We need to hold on to the BufferState entry until then,
+  // because it contains the consumer hold.
+  if (buffer_state_iter->HasZeroConsumerHoldCount())
+    ReleaseBufferState(buffer_state_iter);
+  else
+    buffer_state_iter->set_is_retired();
 }
 
 VideoCaptureController::ControllerClient* VideoCaptureController::FindClient(
     VideoCaptureControllerID id,
     VideoCaptureControllerEventHandler* handler,
     const ControllerClients& clients) {
   for (const auto& client : clients) {
     if (client->controller_id == id && client->event_handler == handler)
       return client.get();
   }
   return nullptr;
 }
 
 VideoCaptureController::ControllerClient* VideoCaptureController::FindClient(
     int session_id,
     const ControllerClients& clients) {
   for (const auto& client : clients) {
     if (client->session_id == session_id)
       return client.get();
   }
   return nullptr;
 }
 
+std::vector<VideoCaptureController::BufferState>::iterator
+VideoCaptureController::FindBufferState(int buffer_id) {
+  auto buffer_state_iter =
+      std::find_if(buffer_states_.begin(), buffer_states_.end(),
+                   [buffer_id](const BufferState& entry) {
+                     return entry.buffer_id() == buffer_id;
+                   });
+  return buffer_state_iter;
+}
+
+void VideoCaptureController::OnClientFinishedConsumingBuffer(
+    ControllerClient* client,
+    int buffer_id,
+    double consumer_resource_utilization) {
+  auto buffer_state_iter = FindBufferState(buffer_id);
+  DCHECK(buffer_state_iter != buffer_states_.end());
+
+  buffer_state_iter->RecordConsumerUtilization(consumer_resource_utilization);
+  buffer_state_iter->DecreaseConsumerCount();
+  if (buffer_state_iter->HasZeroConsumerHoldCount() &&
+      buffer_state_iter->is_retired()) {
+    ReleaseBufferState(buffer_state_iter);
+  }
+}
+
+void VideoCaptureController::ReleaseBufferState(
+    const std::vector<BufferState>::iterator& buffer_state_iter) {
+  for (const auto& client : controller_clients_) {
+    if (client->session_closed)
+      continue;
+
+    auto known_buffers_entry_iter = std::find(std::begin(client->known_buffers),
+                                              std::end(client->known_buffers),
+                                              buffer_state_iter->buffer_id());
+    if (known_buffers_entry_iter != std::end(client->known_buffers)) {
+      client->known_buffers.erase(known_buffers_entry_iter);
+      client->event_handler->OnBufferDestroyed(client->controller_id,
+                                               buffer_state_iter->buffer_id());
+    }
+  }
+  buffer_states_.erase(buffer_state_iter);
+}
+
 }  // namespace content