Tie multibuffers to URLs

media/blink/multibuffer_data_source.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/blink/multibuffer_data_source.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/location.h"
+#include "base/single_thread_task_runner.h"
+#include "media/base/media_log.h"
+#include "media/blink/multibuffer_reader.h"
+#include "net/base/net_errors.h"
+
+using blink::WebFrame;
+
+namespace {
+
+// Minimum preload buffer.
+const int64 kMinBufferPreload = 2 << 20;  // 2 Mb
+// Maxmimum preload buffer.
+const int64 kMaxBufferPreload = 20 << 20;  // 20 Mb
+
+// Preload this much extra, then stop preloading until we fall below the
+// kTargetSecondsBufferedAhead.
+const int64 kPreloadHighExtra = 1 << 20;  // 1 Mb
+
+// Total size of the pinned region in the cache.
+const int64 kMaxBufferSize = 25 << 20;  // 25 Mb
+
+// If bitrate is not known, use this.
+const int64 kDefaultBitrate = 200 * 8 << 10;  // 200 Kbps.
+
+// Maximum bitrate for buffer calculations.
+const int64 kMaxBitrate = 20 * 8 << 20;  // 20 Mbps.
+
+// Maximum playback rate for buffer calculations.
+const double kMaxPlaybackRate = 25.0;
+
+// Preload this many seconds of data by default.
+const int64 kTargetSecondsBufferedAhead = 10;
+
+// Keep this many seconds of data for going back by default.
+const int64 kTargetSecondsBufferedBehind = 2;
+
+}  // namespace
+
+namespace media {
+
+template <typename T>
+T clamp(T value, T min, T max) {
+  return std::max(std::min(value, max), min);
+}
+
+class MultibufferDataSource::ReadOperation {
+ public:
+  ReadOperation(int64 position,
+                int size,
+                uint8* data,
+                const DataSource::ReadCB& callback);
+  ~ReadOperation();
+
+  // Runs |callback_| with the given |result|, deleting the operation
+  // afterwards.
+  static void Run(scoped_ptr<ReadOperation> read_op, int result);
+
+  int64 position() { return position_; }
+  int size() { return size_; }
+  uint8* data() { return data_; }
+
+ private:
+  const int64 position_;
+  const int size_;
+  uint8* data_;
+  DataSource::ReadCB callback_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ReadOperation);
+};
+
+MultibufferDataSource::ReadOperation::ReadOperation(
+    int64 position,
+    int size,
+    uint8* data,
+    const DataSource::ReadCB& callback)
+    : position_(position), size_(size), data_(data), callback_(callback) {
+  DCHECK(!callback_.is_null());
+}
+
+MultibufferDataSource::ReadOperation::~ReadOperation() {
+  DCHECK(callback_.is_null());
+}
+
+// static
+void MultibufferDataSource::ReadOperation::Run(
+    scoped_ptr<ReadOperation> read_op,
+    int result) {
+  base::ResetAndReturn(&read_op->callback_).Run(result);
+}
+
+MultibufferDataSource::MultibufferDataSource(
+    const GURL& url,
+    UrlData::CORSMode cors_mode,
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+    linked_ptr<ResourceMultiBuffer> multibuffer,
+    WebFrame* frame,
+    MediaLog* media_log,
+    BufferedDataSourceHost* host,
+    const DownloadingCB& downloading_cb)
+    : cors_mode_(cors_mode),
+      total_bytes_(kPositionNotSpecified),
+      streaming_(false),
+      loading_(false),
+      render_task_runner_(task_runner),
+      multibuffer_(multibuffer),
+      frame_(frame),
+      stop_signal_received_(false),
+      media_has_played_(false),
+      single_origin_(true),
+      cancel_on_defer_(false),
+      preload_(AUTO),
+      bitrate_(0),
+      playback_rate_(0.0),
+      media_log_(media_log),
+      host_(host),
+      downloading_cb_(downloading_cb),
+      weak_factory_(this) {
+  weak_ptr_ = weak_factory_.GetWeakPtr();
+  DCHECK(host_);
+  DCHECK(!downloading_cb_.is_null());
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  url_data_ = multibuffer_->url_index()->GetByUrl(url, cors_mode_);
+  url_data_->Use();
+  DCHECK(url_data_);
+}
+
+MultibufferDataSource::~MultibufferDataSource() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+}
+
+bool MultibufferDataSource::media_has_played() const {
+  return media_has_played_;
+}
+
+bool MultibufferDataSource::assume_fully_buffered() {
+  return !url_data_->url().SchemeIsHTTPOrHTTPS();
+}
+
+void MultibufferDataSource::CreateResourceLoader(int64 first_byte_position,
+                                                 int64 last_byte_position) {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+
+  base::WeakPtr<MultibufferDataSource> weak_this = weak_factory_.GetWeakPtr();
+  reader_.reset(new MultiBufferReader(
+      multibuffer_.get(),
+      destination_url_data_ ? destination_url_data_ : url_data_,
+      first_byte_position, last_byte_position,
+      base::Bind(&MultibufferDataSource::ProgressCallback, weak_this)));
+  UpdateBufferSizes();
+}
+
+void MultibufferDataSource::Initialize(const InitializeCB& init_cb) {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  DCHECK(!init_cb.is_null());
+  DCHECK(!reader_.get());
+
+  init_cb_ = init_cb;
+
+  CreateResourceLoader(0, kPositionNotSpecified);
+
+  base::WeakPtr<MultibufferDataSource> weak_this = weak_factory_.GetWeakPtr();
+
+  // We're not allowed to call Wait() if data is already available.
+  if (reader_->Available()) {
+    render_task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MultibufferDataSource::StartCallback, weak_this));
+  } else {
+    reader_->Wait(1,
+                  base::Bind(&MultibufferDataSource::StartCallback, weak_this));
+  }
+  UpdateLoadingState();
+}
+
+void MultibufferDataSource::SetPreload(Preload preload) {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  preload_ = preload;
+  UpdateBufferSizes();
+}
+
+bool MultibufferDataSource::HasSingleOrigin() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  DCHECK(init_cb_.is_null() && reader_.get())
+      << "Initialize() must complete before calling HasSingleOrigin()";
+  return single_origin_;
+}
+
+bool MultibufferDataSource::DidPassCORSAccessCheck() const {
+  if (cors_mode_ == UrlData::kUnspecified)
+    return false;
+  // If init_cb is set, we initialization is not finished yet.
+  if (!init_cb_.is_null())
+    return false;
+  // Loader will be false if there was a failure.
+  if (!reader_)
+    return false;
+  return true;
+}
+
+void MultibufferDataSource::Abort() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  {
+    base::AutoLock auto_lock(lock_);
+    StopInternal_Locked();
+  }
+  StopLoader();
+  frame_ = NULL;
+}
+
+void MultibufferDataSource::MediaPlaybackRateChanged(double playback_rate) {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  DCHECK(reader_.get());
+
+  if (playback_rate < 0.0)
+    return;
+
+  playback_rate_ = playback_rate;
+  cancel_on_defer_ = false;
+  UpdateBufferSizes();
+}
+
+void MultibufferDataSource::MediaIsPlaying() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  media_has_played_ = true;
+  cancel_on_defer_ = false;
+  paused_ = false;
+  preload_ = AUTO;
+  UpdateBufferSizes();
+}
+
+void MultibufferDataSource::MediaIsPaused() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  paused_ = true;
+  UpdateBufferSizes();
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// DataSource implementation.
+void MultibufferDataSource::Stop() {
+  {
+    base::AutoLock auto_lock(lock_);
+    StopInternal_Locked();
+  }
+
+  render_task_runner_->PostTask(FROM_HERE,
+                                base::Bind(&MultibufferDataSource::StopLoader,
+                                           weak_factory_.GetWeakPtr()));
+}
+
+void MultibufferDataSource::SetBitrate(int bitrate) {
+  render_task_runner_->PostTask(
+      FROM_HERE, base::Bind(&MultibufferDataSource::SetBitrateTask,
+                            weak_factory_.GetWeakPtr(), bitrate));
+}
+
+void MultibufferDataSource::OnBufferingHaveEnough() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  if (reader_ && preload_ == METADATA && !media_has_played_ && !IsStreaming()) {
+    cancel_on_defer_ = true;
+    if (!loading_)
+      reader_.reset(nullptr);
+  }
+}
+
+void MultibufferDataSource::Read(int64 position,
+                                 int size,
+                                 uint8* data,
+                                 const DataSource::ReadCB& read_cb) {
+  DVLOG(1) << "Read: " << position << " offset, " << size << " bytes";
+  // Reading is not allowed until after initialization.
+  DCHECK(init_cb_.is_null());
+  DCHECK(!read_cb.is_null());
+
+  {
+    base::AutoLock auto_lock(lock_);
+    DCHECK(!read_op_);
+
+    if (stop_signal_received_) {
+      read_cb.Run(kReadError);
+      return;
+    }
+
+    read_op_.reset(new ReadOperation(position, size, data, read_cb));
+  }
+
+  render_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&MultibufferDataSource::ReadTask, weak_factory_.GetWeakPtr()));
+}
+
+bool MultibufferDataSource::GetSize(int64* size_out) {
+  if (destination_url_data_) {
+    *size_out = destination_url_data_->length();
+    if (*size_out != kPositionNotSpecified) {
+      return true;
+    }
+  }
+  *size_out = 0;
+  return false;
+}
+
+bool MultibufferDataSource::IsStreaming() {
+  return streaming_;
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// This method is the place where actual read happens,
+void MultibufferDataSource::ReadTask() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+
+  base::AutoLock auto_lock(lock_);
+  int bytes_read = 0;
+  if (stop_signal_received_)
+    return;
+  DCHECK(read_op_);
+  DCHECK(read_op_->size());
+
+  if (!reader_) {
+    CreateResourceLoader(read_op_->position(), kPositionNotSpecified);
+  } else {
+    reader_->Seek(read_op_->position());
+  }
+
+  int64_t available = reader_->Available();
+  if (available < 0) {
+    // A failure has occured.
+    ReadOperation::Run(read_op_.Pass(), kReadError);
+    return;
+  }
+  if (available) {
+    bytes_read =
+        static_cast<int>(std::min<int64_t>(available, read_op_->size()));
+    bytes_read = reader_->TryRead(read_op_->data(), bytes_read);
+    ReadOperation::Run(read_op_.Pass(), bytes_read);
+  } else {
+    reader_->Wait(1, base::Bind(&MultibufferDataSource::ReadTask,
+                                weak_factory_.GetWeakPtr()));
+    UpdateLoadingState();
+  }
+}
+
+void MultibufferDataSource::StopInternal_Locked() {
+  lock_.AssertAcquired();
+  if (stop_signal_received_)
+    return;
+
+  stop_signal_received_ = true;
+
+  // Initialize() isn't part of the DataSource interface so don't call it in
+  // response to Stop().
+  init_cb_.Reset();
+
+  if (read_op_)
+    ReadOperation::Run(read_op_.Pass(), kReadError);
+}
+
+void MultibufferDataSource::StopLoader() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  reader_.reset(nullptr);
+  UpdateLoadingState();
+}
+
+void MultibufferDataSource::SetBitrateTask(int bitrate) {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  DCHECK(reader_.get());
+
+  bitrate_ = bitrate;
+  UpdateBufferSizes();
+}
+
+/////////////////////////////////////////////////////////////////////////////
+// BufferedResourceLoader callback methods.
+void MultibufferDataSource::StartCallback() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  DCHECK(reader_);
+
+  bool init_cb_is_null = false;
+  {
+    base::AutoLock auto_lock(lock_);
+    init_cb_is_null = init_cb_.is_null();
+  }
+  if (init_cb_is_null) {
+    reader_.reset();
+    return;
+  }
+
+  destination_url_data_ = reader_->GetUrlData();
+
+  // All responses must be successful. Resources that are assumed to be fully
+  // buffered must have a known content length.
+  bool success = reader_->Available() > 0 && destination_url_data_ &&
+                 (!assume_fully_buffered() ||
+                  destination_url_data_->length() != kPositionNotSpecified);
+
+  if (success) {
+    total_bytes_ = destination_url_data_->length();
+    streaming_ =
+        !assume_fully_buffered() && (total_bytes_ == kPositionNotSpecified ||
+                                     !destination_url_data_->range_supported());
+
+    media_log_->SetDoubleProperty("total_bytes",
+                                  static_cast<double>(total_bytes_));
+    media_log_->SetBooleanProperty("streaming", streaming_);
+  } else {
+    reader_.reset(nullptr);
+  }
+
+  // TODO(scherkus): we shouldn't have to lock to signal host(), see
+  // http://crbug.com/113712 for details.
+  base::AutoLock auto_lock(lock_);
+  if (stop_signal_received_)
+    return;
+
+  if (success) {
+    if (total_bytes_ != kPositionNotSpecified) {
+      host_->SetTotalBytes(total_bytes_);
+      if (assume_fully_buffered())
+        host_->AddBufferedByteRange(0, total_bytes_);
+    }
+
+    // Progress callback might be called after the start callback,
+    // make sure that we update single_origin_ now.
+    UpdateSingleOrigin();
+
+    media_log_->SetBooleanProperty("single_origin", single_origin_);
+    media_log_->SetBooleanProperty("passed_cors_access_check",
+                                   DidPassCORSAccessCheck());
+    media_log_->SetBooleanProperty("range_header_supported",
+                                   destination_url_data_->range_supported());
+  }
+
+  UpdateLoadingState();
+  render_task_runner_->PostTask(
+      FROM_HERE, base::Bind(base::ResetAndReturn(&init_cb_), success));
+}
+
+void MultibufferDataSource::UpdateSingleOrigin() {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+  if (reader_ && destination_url_data_) {
+    scoped_refptr<UrlData> new_url_data = reader_->GetUrlData();
+    if (new_url_data && new_url_data != destination_url_data_) {
+      // A redirect has happened.
+      // Check if origin has changed.
+      if (destination_url_data_->url().GetOrigin() !=
+          new_url_data->url().GetOrigin()) {
+        single_origin_ = false;
+      }
+    }
+  }
+}
+
+void MultibufferDataSource::ProgressCallback(int64 begin, int64 end) {
+  DCHECK(render_task_runner_->BelongsToCurrentThread());
+
+  UpdateSingleOrigin();
+  if (assume_fully_buffered())
+    return;
+
+  if (end > begin) {
+    // TODO(scherkus): we shouldn't have to lock to signal host(), see
+    // http://crbug.com/113712 for details.
+    base::AutoLock auto_lock(lock_);
+    if (stop_signal_received_)
+      return;
+
+    host_->AddBufferedByteRange(begin, end);
+  }
+
+  UpdateLoadingState();
+}
+
+void MultibufferDataSource::UpdateLoadingState() {
+  // Update loading state.
+  if ((!!reader_ && reader_->IsLoading()) != loading_) {
+    loading_ = !loading_;
+
+    if (!loading_ && cancel_on_defer_) {
+      reader_.reset(nullptr);
+    }
+
+    // Callback could kill us, be sure to call it last.
+    downloading_cb_.Run(loading_);
+  }
+}
+
+void MultibufferDataSource::UpdateBufferSizes() {
+  if (!reader_)
+    return;
+
+  if (!assume_fully_buffered()) {
+    // If the playback has started and we're paused, then try to load as much as
+    // possible, assuming that the file is cacheable. (If not, why bother?)
+    if (media_has_played_ && paused_ && destination_url_data_ &&
+        destination_url_data_->range_supported() &&
+        destination_url_data_->cacheable()) {
+      reader_->SetPreload(1LL << 40, 1LL << 40);  // 1 Tb
+      return;
+    }
+  }
+
+  // Use a default bit rate if unknown and clamp to prevent overflow.
+  int64 bitrate = clamp<int64>(bitrate_, 0, kMaxBitrate);
+  if (bitrate == 0)
+    bitrate = kDefaultBitrate;
+
+  // Only scale the buffer window for playback rates greater than 1.0 in
+  // magnitude and clamp to prevent overflow.
+  bool backward_playback = false;
+  double playback_rate = playback_rate_;
+  if (playback_rate < 0.0) {
+    backward_playback = true;
+    playback_rate *= -1.0;
+  }
+
+  playback_rate = std::max(playback_rate, 1.0);
+  playback_rate = std::min(playback_rate, kMaxPlaybackRate);
+
+  int64 bytes_per_second = (bitrate / 8.0) * playback_rate;
+
+  int64 preload = clamp(kTargetSecondsBufferedAhead * bytes_per_second,
+                        kMinBufferPreload, kMaxBufferPreload);
+  int64 back_buffer = clamp(kTargetSecondsBufferedBehind * bytes_per_second,
+                            kMinBufferPreload, kMaxBufferPreload);
+  if (backward_playback)
+    std::swap(preload, back_buffer);
+
+  int64 pin_forwards = kMaxBufferSize - back_buffer;
+  DCHECK_LE(preload_ + kPreloadHighExtra, pin_forwards);
+  reader_->SetMaxBuffer(back_buffer, pin_forwards);
+
+  if (preload_ == METADATA) {
+    reader_->SetPreload(0, 0);
+  } else {
+    reader_->SetPreload(preload + kPreloadHighExtra, preload);
+  }
+}
+
+}  // namespace media