content/renderer/media/buffered_data_source.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_MEDIA_BUFFERED_DATA_SOURCE_H_
   6 #define CONTENT_RENDERER_MEDIA_BUFFERED_DATA_SOURCE_H_
   7
   8 #include <string>
   9
  10 #include "base/callback.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/synchronization/lock.h"
  13 #include "content/common/content_export.h"
  14 #include "content/renderer/media/buffered_resource_loader.h"
  15 #include "content/renderer/media/preload.h"
  16 #include "media/base/data_source.h"
  17 #include "media/base/ranges.h"
  18 #include "url/gurl.h"
  19
  20 namespace base {
  21 class SingleThreadTaskRunner;
  22 }
  23
  24 namespace media {
  25 class MediaLog;
  26 }
  27
  28 namespace content {
  29
  30 class CONTENT_EXPORT BufferedDataSourceHost {
  31  public:
  32   // Notify the host of the total size of the media file.
  33   virtual void SetTotalBytes(int64 total_bytes) = 0;
  34
  35   // Notify the host that byte range [start,end] has been buffered.
  36   // TODO(fischman): remove this method when demuxing is push-based instead of
  37   // pull-based.  http://crbug.com/131444
  38   virtual void AddBufferedByteRange(int64 start, int64 end) = 0;
  39
  40  protected:
  41   virtual ~BufferedDataSourceHost() {};
  42 };
  43
  44 // A data source capable of loading URLs and buffering the data using an
  45 // in-memory sliding window.
  46 //
  47 // BufferedDataSource must be created and initialized on the render thread
  48 // before being passed to other threads. It may be deleted on any thread.
  49 class CONTENT_EXPORT BufferedDataSource : public media::DataSource {
  50  public:
  51   typedef base::Callback<void(bool)> DownloadingCB;
  52
  53   // |url| and |cors_mode| are passed to the object. Buffered byte range changes
  54   // will be reported to |host|. |downloading_cb| will be called whenever the
  55   // downloading/paused state of the source changes.
  56   BufferedDataSource(
  57       const GURL& url,
  58       BufferedResourceLoader::CORSMode cors_mode,
  59       const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
  60       blink::WebFrame* frame,
  61       media::MediaLog* media_log,
  62       BufferedDataSourceHost* host,
  63       const DownloadingCB& downloading_cb);
  64   virtual ~BufferedDataSource();
  65
  66   // Executes |init_cb| with the result of initialization when it has completed.
  67   //
  68   // Method called on the render thread.
  69   typedef base::Callback<void(bool)> InitializeCB;
  70   void Initialize(const InitializeCB& init_cb);
  71
  72   // Adjusts the buffering algorithm based on the given preload value.
  73   void SetPreload(Preload preload);
  74
  75   // Returns true if the media resource has a single origin, false otherwise.
  76   // Only valid to call after Initialize() has completed.
  77   //
  78   // Method called on the render thread.
  79   bool HasSingleOrigin();
  80
  81   // Returns true if the media resource passed a CORS access control check.
  82   bool DidPassCORSAccessCheck() const;
  83
  84   // Cancels initialization, any pending loaders, and any pending read calls
  85   // from the demuxer. The caller is expected to release its reference to this
  86   // object and never call it again.
  87   //
  88   // Method called on the render thread.
  89   void Abort();
  90
  91   // Notifies changes in playback state for controlling media buffering
  92   // behavior.
  93   void MediaPlaybackRateChanged(float playback_rate);
  94   void MediaIsPlaying();
  95   void MediaIsPaused();
  96
  97   // Returns true if the resource is local.
  98   bool assume_fully_buffered() { return !url_.SchemeIsHTTPOrHTTPS(); }
  99
 100   // media::DataSource implementation.
 101   // Called from demuxer thread.
 102   virtual void Stop() OVERRIDE;
 103
 104   virtual void Read(int64 position, int size, uint8* data,
 105                     const media::DataSource::ReadCB& read_cb) OVERRIDE;
 106   virtual bool GetSize(int64* size_out) OVERRIDE;
 107   virtual bool IsStreaming() OVERRIDE;
 108   virtual void SetBitrate(int bitrate) OVERRIDE;
 109
 110  protected:
 111   // A factory method to create a BufferedResourceLoader based on the read
 112   // parameters. We can override this file to object a mock
 113   // BufferedResourceLoader for testing.
 114   virtual BufferedResourceLoader* CreateResourceLoader(
 115       int64 first_byte_position, int64 last_byte_position);
 116
 117  private:
 118   friend class BufferedDataSourceTest;
 119
 120   // Task posted to perform actual reading on the render thread.
 121   void ReadTask();
 122
 123   // Cancels oustanding callbacks and sets |stop_signal_received_|. Safe to call
 124   // from any thread.
 125   void StopInternal_Locked();
 126
 127   // Stops |loader_| if present. Used by Abort() and Stop().
 128   void StopLoader();
 129
 130   // Tells |loader_| the bitrate of the media.
 131   void SetBitrateTask(int bitrate);
 132
 133   // The method that performs actual read. This method can only be executed on
 134   // the render thread.
 135   void ReadInternal();
 136
 137   // BufferedResourceLoader::Start() callback for initial load.
 138   void StartCallback(BufferedResourceLoader::Status status);
 139
 140   // BufferedResourceLoader::Start() callback for subsequent loads (i.e.,
 141   // when accessing ranges that are outside initial buffered region).
 142   void PartialReadStartCallback(BufferedResourceLoader::Status status);
 143
 144   // BufferedResourceLoader callbacks.
 145   void ReadCallback(BufferedResourceLoader::Status status, int bytes_read);
 146   void LoadingStateChangedCallback(BufferedResourceLoader::LoadingState state);
 147   void ProgressCallback(int64 position);
 148
 149   // Update |loader_|'s deferring strategy in response to a play/pause, or
 150   // change in playback rate.
 151   void UpdateDeferStrategy(bool paused);
 152
 153   // URL of the resource requested.
 154   GURL url_;
 155   // crossorigin attribute on the corresponding HTML media element, if any.
 156   BufferedResourceLoader::CORSMode cors_mode_;
 157
 158   // The total size of the resource. Set during StartCallback() if the size is
 159   // known, otherwise it will remain kPositionNotSpecified until the size is
 160   // determined by reaching EOF.
 161   int64 total_bytes_;
 162
 163   // This value will be true if this data source can only support streaming.
 164   // i.e. range request is not supported.
 165   bool streaming_;
 166
 167   // A webframe for loading.
 168   blink::WebFrame* frame_;
 169
 170   // A resource loader for the media resource.
 171   scoped_ptr<BufferedResourceLoader> loader_;
 172
 173   // Callback method from the pipeline for initialization.
 174   InitializeCB init_cb_;
 175
 176   // Read parameters received from the Read() method call. Must be accessed
 177   // under |lock_|.
 178   class ReadOperation;
 179   scoped_ptr<ReadOperation> read_op_;
 180
 181   // This buffer is intermediate, we use it for BufferedResourceLoader to write
 182   // to. And when read in BufferedResourceLoader is done, we copy data from
 183   // this buffer to |read_buffer_|. The reason for an additional copy is that
 184   // we don't own |read_buffer_|. But since the read operation is asynchronous,
 185   // |read_buffer| can be destroyed at any time, so we only copy into
 186   // |read_buffer| in the final step when it is safe.
 187   // Memory is allocated for this member during initialization of this object
 188   // because we want buffer to be passed into BufferedResourceLoader to be
 189   // always non-null. And by initializing this member with a default size we can
 190   // avoid creating zero-sized buffered if the first read has zero size.
 191   scoped_ptr<uint8[]> intermediate_read_buffer_;
 192   int intermediate_read_buffer_size_;
 193
 194   // The task runner of the render thread.
 195   const scoped_refptr<base::SingleThreadTaskRunner> render_task_runner_;
 196
 197   // Protects |stop_signal_received_| and |read_op_|.
 198   base::Lock lock_;
 199
 200   // Whether we've been told to stop via Abort() or Stop().
 201   bool stop_signal_received_;
 202
 203   // This variable is true when the user has requested the video to play at
 204   // least once.
 205   bool media_has_played_;
 206
 207   // This variable holds the value of the preload attribute for the video
 208   // element.
 209   Preload preload_;
 210
 211   // Bitrate of the content, 0 if unknown.
 212   int bitrate_;
 213
 214   // Current playback rate.
 215   float playback_rate_;
 216
 217   scoped_refptr<media::MediaLog> media_log_;
 218
 219   // Host object to report buffered byte range changes to.
 220   BufferedDataSourceHost* host_;
 221
 222   DownloadingCB downloading_cb_;
 223
 224   // NOTE: Weak pointers must be invalidated before all other member variables.
 225   base::WeakPtrFactory<BufferedDataSource> weak_factory_;
 226
 227   DISALLOW_COPY_AND_ASSIGN(BufferedDataSource);
 228 };
 229
 230 }  // namespace content
 231
 232 #endif  // CONTENT_RENDERER_MEDIA_BUFFERED_DATA_SOURCE_H_