Video Buffering: Caches data to disk when paused (resubmit)

webkit/glue/media/buffered_data_source.cc

 // Copyright (c) 2010 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 "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 #include "base/process_util.h"
 #include "base/stl_util-inl.h"
 #include "base/string_util.h"
@@ skipping 51 matching lines @@
   return url.SchemeIs(kHttpScheme) || url.SchemeIs(kHttpsScheme);
 }
 
 bool IsDataProtocol(const GURL& url) {
   return url.SchemeIs(kDataScheme);
 }
 
 }  // namespace
 
 namespace webkit_glue {
-
 /////////////////////////////////////////////////////////////////////////////
 // BufferedResourceLoader
 BufferedResourceLoader::BufferedResourceLoader(
     webkit_glue::MediaResourceLoaderBridgeFactory* bridge_factory,
     const GURL& url,
     int64 first_byte_position,
     int64 last_byte_position)
     : buffer_(new media::SeekableBuffer(kBackwardCapcity, kForwardCapacity)),
       deferred_(false),
+      defer_allowed_(true),
       completed_(false),
       range_requested_(false),
       partial_response_(false),
       bridge_factory_(bridge_factory),
       url_(url),
       first_byte_position_(first_byte_position),
       last_byte_position_(last_byte_position),
       start_callback_(NULL),
       bridge_(NULL),
       offset_(0),
@@ skipping 126 matching lines @@
     return offset_ - static_cast<int>(buffer_->backward_bytes());
   return kPositionNotSpecified;
 }
 
 int64 BufferedResourceLoader::GetBufferedLastBytePosition() {
   if (buffer_.get())
     return offset_ + static_cast<int>(buffer_->forward_bytes()) - 1;
   return kPositionNotSpecified;
 }
 
+void BufferedResourceLoader::SetAllowDefer(bool is_allowed) {
+  defer_allowed_ = is_allowed;
+  DisableDeferIfNeeded();
+}
+
 /////////////////////////////////////////////////////////////////////////////
 // BufferedResourceLoader,
 //     webkit_glue::ResourceLoaderBridge::Peer implementations
 bool BufferedResourceLoader::OnReceivedRedirect(
     const GURL& new_url,
     const webkit_glue::ResourceLoaderBridge::ResponseInfo& info,
     bool* has_new_first_party_for_cookies,
     GURL* new_first_party_for_cookies) {
   DCHECK(bridge_.get());
 
@@ skipping 81 matching lines @@
   // In this case we shouldn't do anything.
   if (!buffer_.get())
     return;
 
   // Writes more data to |buffer_|.
   buffer_->Append(reinterpret_cast<const uint8*>(data), len);
 
   // If there is an active read request, try to fulfill the request.
   if (HasPendingRead() && CanFulfillRead()) {
     ReadInternal();
+  } else if (!defer_allowed_) {
+    // If we're not allowed to defer, slide the buffer window forward instead
+    // of deferring.
+    if (buffer_->forward_bytes() > buffer_->forward_capacity()) {
+      size_t excess = buffer_->forward_bytes() - buffer_->forward_capacity();
+      bool success = buffer_->Seek(excess);
+      DCHECK(success);
+      offset_ += first_offset_ + excess;
+    }
   }
 
   // At last see if the buffer is full and we need to defer the downloading.
   EnableDeferIfNeeded();
 
   // Notify that we have received some data.
   NotifyNetworkEvent();
 }
 
 void BufferedResourceLoader::OnCompletedRequest(
@@ skipping 35 matching lines @@
   // We incremented the reference count when the loader was started. We balance
   // that reference here so that we get destroyed. This is also the only safe
   // place to destroy the ResourceLoaderBridge.
   bridge_.reset();
   Release();
 }
 
 /////////////////////////////////////////////////////////////////////////////
 // BufferedResourceLoader, private
 void BufferedResourceLoader::EnableDeferIfNeeded() {
+  if (!defer_allowed_)
+    return;
+
   if (!deferred_ &&
       buffer_->forward_bytes() >= buffer_->forward_capacity()) {
     deferred_ = true;
 
     if (bridge_.get())
       bridge_->SetDefersLoading(true);
 
     NotifyNetworkEvent();
   }
 }
 
 void BufferedResourceLoader::DisableDeferIfNeeded() {
   if (deferred_ &&
-      buffer_->forward_bytes() < buffer_->forward_capacity() / 2) {
+      (!defer_allowed_ ||
+       buffer_->forward_bytes() < buffer_->forward_capacity() / 2)) {
     deferred_ = false;
 
     if (bridge_.get())
       bridge_->SetDefersLoading(false);
 
     NotifyNetworkEvent();
   }
 }
 
 bool BufferedResourceLoader::CanFulfillRead() {
@@ skipping 124 matching lines @@
       initialize_callback_(NULL),
       read_callback_(NULL),
       read_position_(0),
       read_size_(0),
       read_buffer_(NULL),
       read_attempts_(0),
       intermediate_read_buffer_(new uint8[kInitialReadBufferSize]),
       intermediate_read_buffer_size_(kInitialReadBufferSize),
       render_loop_(render_loop),
       stop_signal_received_(false),
-      stopped_on_render_loop_(false) {
+      stopped_on_render_loop_(false),
+      media_is_paused_(true) {
 }
 
 BufferedDataSource::~BufferedDataSource() {
 }
 
 // A factory method to create BufferedResourceLoader using the read parameters.
 // This method can be overrided to inject mock BufferedResourceLoader object
 // for testing purpose.
 BufferedResourceLoader* BufferedDataSource::CreateResourceLoader(
     int64 first_byte_position, int64 last_byte_position) {
@@ skipping 45 matching lines @@
     stop_signal_received_ = true;
   }
   if (callback) {
     callback->Run();
     delete callback;
   }
   render_loop_->PostTask(FROM_HERE,
       NewRunnableMethod(this, &BufferedDataSource::CleanupTask));
 }
 
+void BufferedDataSource::SetPlaybackRate(float playback_rate) {
+  render_loop_->PostTask(FROM_HERE,
+      NewRunnableMethod(this, &BufferedDataSource::SetPlaybackRateTask,
+                        playback_rate));
+}
+
 /////////////////////////////////////////////////////////////////////////////
 // BufferedDataSource, media::DataSource implementation
 void BufferedDataSource::Read(int64 position, size_t size, uint8* data,
                               media::DataSource::ReadCallback* read_callback) {
   render_loop_->PostTask(FROM_HERE,
       NewRunnableMethod(this, &BufferedDataSource::ReadTask,
                         position, static_cast<int>(size), data, read_callback));
 }
 
 bool BufferedDataSource::GetSize(int64* size_out) {
@@ skipping 105 matching lines @@
   // 3. CleanupTask() is executed.
   // 4. RestartLoadingTask() is executed.
   if (stopped_on_render_loop_)
     return;
 
   // If there's no outstanding read then return early.
   if (!read_callback_.get())
     return;
 
   loader_ = CreateResourceLoader(read_position_, -1);
+  loader_->SetAllowDefer(!media_is_paused_);
   loader_->Start(
       NewCallback(this, &BufferedDataSource::PartialReadStartCallback),
       NewCallback(this, &BufferedDataSource::NetworkEventCallback));
 }
 
 void BufferedDataSource::WatchDogTask() {
   DCHECK(MessageLoop::current() == render_loop_);
   DCHECK(!stopped_on_render_loop_);
 
   // We only care if there is an active read request.
@@ skipping 10 matching lines @@
   if (read_attempts_ >= kReadTrials)
     return;
 
   ++read_attempts_;
   read_submitted_time_ = base::Time::Now();
 
   // Stops the current loader and creates a new resource loader and
   // retry the request.
   loader_->Stop();
   loader_ = CreateResourceLoader(read_position_, -1);
+  loader_->SetAllowDefer(!media_is_paused_);
   loader_->Start(
       NewCallback(this, &BufferedDataSource::PartialReadStartCallback),
       NewCallback(this, &BufferedDataSource::NetworkEventCallback));
 }
 
+void BufferedDataSource::SetPlaybackRateTask(float playback_rate) {
+  DCHECK(MessageLoop::current() == render_loop_);
+  DCHECK(loader_.get());
+
+  bool previously_paused = media_is_paused_;
+  media_is_paused_ = (playback_rate == 0.0);
+
+  // Disallow deferring data when we are pausing, allow deferring data
+  // when we resume playing.
+  if (previously_paused && !media_is_paused_) {
+    loader_->SetAllowDefer(true);
+  } else if (!previously_paused && media_is_paused_) {
+    loader_->SetAllowDefer(false);
+  }
+}
+
 // This method is the place where actual read happens, |loader_| must be valid
 // prior to make this method call.
 void BufferedDataSource::ReadInternal() {
   DCHECK(MessageLoop::current() == render_loop_);
   DCHECK(loader_.get());
 
   // First we prepare the intermediate read buffer for BufferedResourceLoader
   // to write to.
   if (read_size_ > intermediate_read_buffer_size_) {
     intermediate_read_buffer_.reset(new uint8[read_size_]);
@@ skipping 222 matching lines @@
     return;
 
   if (network_activity != network_activity_) {
     network_activity_ = network_activity;
     host()->SetNetworkActivity(network_activity);
   }
   host()->SetBufferedBytes(buffered_last_byte_position + 1);
 }
 
 }  // namespace webkit_glue