Add a buffering controller for Chromecast.

chromecast/media/cma/base/buffering_state.cc

+// Copyright 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.
+
+#include "chromecast/media/cma/base/buffering_state.h"
+
+#include <sstream>
+
+#include "base/logging.h"
+#include "media/base/buffers.h"
+
+namespace media {
+namespace cma {
+
+BufferingConfig::BufferingConfig(
+    base::TimeDelta low_level_threshold,
+    base::TimeDelta high_level_threshold)
+    : low_level_threshold_(low_level_threshold),
+      high_level_threshold_(high_level_threshold) {
+}
+
+BufferingConfig::~BufferingConfig() {
+}
+
+
+BufferingState::BufferingState(
+    const scoped_refptr<BufferingConfig>& config,
+    const base::Closure& state_changed_cb,
+    const HighLevelBufferCb& high_level_buffer_cb)
+    : config_(config),
+      state_changed_cb_(state_changed_cb),
+      high_level_buffer_cb_(high_level_buffer_cb),
+      state_(kLowLevel),
+      media_time_(kNoTimestamp()),
+      max_rendering_time_(kNoTimestamp()),
+      buffered_time_(kNoTimestamp()) {
+}
+
+BufferingState::~BufferingState() {
+}
+
+void BufferingState::OnConfigChanged() {
+  state_ = GetBufferLevelState();
+}
+
+void BufferingState::SetMediaTime(base::TimeDelta media_time) {
+  media_time_ = media_time;
+  switch (state_) {
+    case kLowLevel:
+    case kMediumLevel:
+    case kHighLevel:
+      UpdateState(GetBufferLevelState());
+      break;
+    case kEosReached:
+      break;
+  }
+}
+
+void BufferingState::SetMaxRenderingTime(base::TimeDelta max_rendering_time) {
+  max_rendering_time_ = max_rendering_time;
+}
+
+base::TimeDelta BufferingState::GetMaxRenderingTime() const {
+  return max_rendering_time_;
+}
+
+void BufferingState::SetBufferedTime(base::TimeDelta buffered_time) {
+  buffered_time_ = buffered_time;
+  switch (state_) {
+    case kLowLevel:
+    case kMediumLevel:
+    case kHighLevel:
+      UpdateState(GetBufferLevelState());
+      break;
+    case kEosReached:
+      break;
+  }
+}
+
+void BufferingState::NotifyEos() {
+  UpdateState(kEosReached);
+}
+
+void BufferingState::NotifyMaxCapacity(base::TimeDelta buffered_time) {
+  if (media_time_ == kNoTimestamp() || buffered_time == kNoTimestamp()) {
+    LOG(WARNING) << "Max capacity with no timestamp";
+    return;
+  }
+  base::TimeDelta buffer_duration = buffered_time - media_time_;
+  if (buffer_duration < config_->high_level())
+    high_level_buffer_cb_.Run(buffer_duration);
+}
+
+std::string BufferingState::ToString() const {
+  std::ostringstream s;
+  s << "state=" << state_
+    << " media_time_ms=" << media_time_.InMilliseconds()
+    << " buffered_time_ms=" << buffered_time_.InMilliseconds()
+    << " low_level_ms=" << config_->low_level().InMilliseconds()
+    << " high_level_ms=" << config_->high_level().InMilliseconds();
+  return s.str();
+}
+
+BufferingState::State BufferingState::GetBufferLevelState() const {
+  if (media_time_ == kNoTimestamp() || buffered_time_ == kNoTimestamp())
+    return kLowLevel;
+
+  base::TimeDelta buffer_duration = buffered_time_ - media_time_;
+  if (buffer_duration < config_->low_level())
+    return kLowLevel;
+  if (buffer_duration >= config_->high_level())
+    return kHighLevel;
+  return kMediumLevel;
+}
+
+void BufferingState::UpdateState(State new_state) {
+  if (new_state == state_)
+    return;
+
+  state_ = new_state;
+  if (!state_changed_cb_.is_null())
+    state_changed_cb_.Run();
+}
+
+}  // namespace cma
+}  // namespace media