blob: 4f380eae15753ab55b546c2df5cd9e5becec2a94 [file] [log] [blame]
// 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 <string>
#include "base/callback.h"
#include "base/memory/scoped_ptr.h"
#include "media/base/media_export.h"
#include "media/base/seekable_buffer.h"
#include "media/blink/active_loader.h"
#include "third_party/WebKit/public/platform/WebURLLoader.h"
#include "third_party/WebKit/public/platform/WebURLLoaderClient.h"
#include "third_party/WebKit/public/platform/WebURLRequest.h"
#include "third_party/WebKit/public/web/WebFrame.h"
#include "url/gurl.h"
namespace media {
class MediaLog;
class SeekableBuffer;
const int64 kPositionNotSpecified = -1;
// BufferedResourceLoader is single threaded and must be accessed on the
// render thread. It wraps a WebURLLoader and does in-memory buffering,
// pausing resource loading when the in-memory buffer is full and resuming
// resource loading when there is available capacity.
class MEDIA_EXPORT BufferedResourceLoader
: NON_EXPORTED_BASE(public blink::WebURLLoaderClient) {
// kNeverDefer - Aggresively buffer; never defer loading while paused.
// kReadThenDefer - Request only enough data to fulfill read requests.
// kCapacityDefer - Try to keep amount of buffered data at capacity.
enum DeferStrategy {
// Status codes for start/read operations on BufferedResourceLoader.
enum Status {
// Everything went as planned.
// The operation failed, which may have been due to:
// - Page navigation
// - Server replied 4xx/5xx
// - The response was invalid
// - Connection was terminated
// At this point you should delete the loader.
// The loader will never be able to satisfy the read request. Please stop,
// delete, create a new loader, and try again.
// Keep in sync with WebMediaPlayer::CORSMode.
enum CORSMode { kUnspecified, kAnonymous, kUseCredentials };
enum LoadingState {
kLoading, // Actively attempting to download data.
kLoadingDeferred, // Loading intentionally deferred.
kLoadingFinished, // Loading finished normally; no more data will arrive.
kLoadingFailed, // Loading finished abnormally; no more data will arrive.
// |url| - URL for the resource to be loaded.
// |cors_mode| - HTML media element's crossorigin attribute.
// |first_byte_position| - First byte to start loading from,
// |kPositionNotSpecified| for not specified.
// |last_byte_position| - Last byte to be loaded,
// |kPositionNotSpecified| for not specified.
// |strategy| is the initial loading strategy to use.
// |bitrate| is the bitrate of the media, 0 if unknown.
// |playback_rate| is the current playback rate of the media.
const GURL& url,
CORSMode cors_mode,
int64 first_byte_position,
int64 last_byte_position,
DeferStrategy strategy,
int bitrate,
float playback_rate,
MediaLog* media_log);
virtual ~BufferedResourceLoader();
// Start the resource loading with the specified URL and range.
// |loading_cb| is executed when the loading state has changed.
// |progress_cb| is executed when additional data has arrived.
typedef base::Callback<void(Status)> StartCB;
typedef base::Callback<void(LoadingState)> LoadingStateChangedCB;
typedef base::Callback<void(int64)> ProgressCB;
void Start(const StartCB& start_cb,
const LoadingStateChangedCB& loading_cb,
const ProgressCB& progress_cb,
blink::WebFrame* frame);
// Stops everything associated with this loader, including active URL loads
// and pending callbacks.
// It is safe to delete a BufferedResourceLoader after calling Stop().
void Stop();
// Copies |read_size| bytes from |position| into |buffer|, executing |read_cb|
// when the operation has completed.
// The callback will contain the number of bytes read iff the status is kOk,
// zero otherwise.
// If necessary will temporarily increase forward capacity of buffer to
// accomodate an unusually large read.
typedef base::Callback<void(Status, int)> ReadCB;
void Read(int64 position, int read_size,
uint8* buffer, const ReadCB& read_cb);
// Gets the content length in bytes of the instance after this loader has been
// started. If this value is |kPositionNotSpecified|, then content length is
// unknown.
int64 content_length();
// Gets the original size of the file requested. If this value is
// |kPositionNotSpecified|, then the size is unknown.
int64 instance_size();
// Returns true if the server supports byte range requests.
bool range_supported();
// blink::WebURLLoaderClient implementation.
virtual void willSendRequest(
blink::WebURLLoader* loader,
blink::WebURLRequest& newRequest,
const blink::WebURLResponse& redirectResponse);
virtual void didSendData(
blink::WebURLLoader* loader,
unsigned long long bytesSent,
unsigned long long totalBytesToBeSent);
virtual void didReceiveResponse(
blink::WebURLLoader* loader,
const blink::WebURLResponse& response);
virtual void didDownloadData(
blink::WebURLLoader* loader,
int data_length,
int encoded_data_length);
virtual void didReceiveData(
blink::WebURLLoader* loader,
const char* data,
int data_length,
int encoded_data_length);
virtual void didReceiveCachedMetadata(
blink::WebURLLoader* loader,
const char* data, int dataLength);
virtual void didFinishLoading(
blink::WebURLLoader* loader,
double finishTime,
int64_t total_encoded_data_length);
virtual void didFail(
blink::WebURLLoader* loader,
const blink::WebURLError&);
// Returns true if the media resource has a single origin, false otherwise.
// Only valid to call after Start() has completed.
bool HasSingleOrigin() const;
// Returns true if the media resource passed a CORS access control check.
// Only valid to call after Start() has completed.
bool DidPassCORSAccessCheck() const;
// Sets the defer strategy to the given value unless it seems unwise.
// Specifically downgrade kNeverDefer to kCapacityDefer if we know the
// current response will not be used to satisfy future requests (the cache
// won't help us).
void UpdateDeferStrategy(DeferStrategy strategy);
// Sets the playback rate to the given value and updates buffer window
// accordingly.
void SetPlaybackRate(float playback_rate);
// Sets the bitrate to the given value and updates buffer window
// accordingly.
void SetBitrate(int bitrate);
// Return the |first_byte_position| passed into the ctor.
int64 first_byte_position() const;
// Parse a Content-Range header into its component pieces and return true if
// each of the expected elements was found & parsed correctly.
// |*instance_size| may be set to kPositionNotSpecified if the range ends in
// "/*".
// NOTE: only public for testing! This is an implementation detail of
// VerifyPartialResponse (a private method).
static bool ParseContentRange(
const std::string& content_range_str, int64* first_byte_position,
int64* last_byte_position, int64* instance_size);
friend class BufferedDataSourceTest;
friend class BufferedResourceLoaderTest;
friend class MockBufferedDataSource;
// Updates the |buffer_|'s forward and backward capacities.
void UpdateBufferWindow();
// Updates deferring behavior based on current buffering scheme.
void UpdateDeferBehavior();
// Sets |active_loader_|'s defer state and fires |loading_cb_| if the state
// changed.
void SetDeferred(bool deferred);
// Returns true if we should defer resource loading based on the current
// buffering scheme.
bool ShouldDefer() const;
// Returns true if the current read request can be fulfilled by what is in
// the buffer.
bool CanFulfillRead() const;
// Returns true if the current read request will be fulfilled in the future.
bool WillFulfillRead() const;
// Method that does the actual read and calls the |read_cb_|, assuming the
// request range is in |buffer_|.
void ReadInternal();
// If we have made a range request, verify the response from the server.
bool VerifyPartialResponse(const blink::WebURLResponse& response);
// Done with read. Invokes the read callback and reset parameters for the
// read request.
void DoneRead(Status status, int bytes_read);
// Done with start. Invokes the start callback and reset it.
void DoneStart(Status status);
bool HasPendingRead() { return !read_cb_.is_null(); }
// Helper function that returns true if a range request was specified.
bool IsRangeRequest() const;
// Log everything interesting to |media_log_|.
void Log();
// A sliding window of buffer.
SeekableBuffer buffer_;
// Keeps track of an active WebURLLoader and associated state.
scoped_ptr<ActiveLoader> active_loader_;
// Tracks if |active_loader_| failed. If so, then all calls to Read() will
// fail.
bool loader_failed_;
// Current buffering algorithm in place for resource loading.
DeferStrategy defer_strategy_;
// True if the currently-reading response might be used to satisfy a future
// request from the cache.
bool might_be_reused_from_cache_in_future_;
// True if Range header is supported.
bool range_supported_;
// Forward capacity to reset to after an extension.
int saved_forward_capacity_;
GURL url_;
CORSMode cors_mode_;
const int64 first_byte_position_;
const int64 last_byte_position_;
bool single_origin_;
// Executed whenever the state of resource loading has changed.
LoadingStateChangedCB loading_cb_;
// Executed whenever additional data has been downloaded and reports the
// zero-indexed file offset of the furthest buffered byte.
ProgressCB progress_cb_;
// Members used during request start.
StartCB start_cb_;
int64 offset_;
int64 content_length_;
int64 instance_size_;
// Members used during a read operation. They should be reset after each
// read has completed or failed.
ReadCB read_cb_;
int64 read_position_;
int read_size_;
uint8* read_buffer_;
// Offsets of the requested first byte and last byte in |buffer_|. They are
// written by Read().
int first_offset_;
int last_offset_;
// Injected WebURLLoader instance for testing purposes.
scoped_ptr<blink::WebURLLoader> test_loader_;
// Bitrate of the media. Set to 0 if unknown.
int bitrate_;
// Playback rate of the media.
float playback_rate_;
scoped_refptr<MediaLog> media_log_;
} // namespace media