1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
|
// 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"
#include "media/base/filter_host.h"
#include "media/base/media_format.h"
#include "net/base/load_flags.h"
#include "net/base/net_errors.h"
#include "net/http/http_response_headers.h"
#include "webkit/glue/media/buffered_data_source.h"
#include "webkit/glue/webkit_glue.h"
#include "webkit/glue/webmediaplayer_impl.h"
namespace {
const char kHttpScheme[] = "http";
const char kHttpsScheme[] = "https";
const char kDataScheme[] = "data";
const int64 kPositionNotSpecified = -1;
const int kHttpOK = 200;
const int kHttpPartialContent = 206;
// Define the number of bytes in a megabyte.
const size_t kMegabyte = 1024 * 1024;
// Backward capacity of the buffer, by default 2MB.
const size_t kBackwardCapcity = 2 * kMegabyte;
// Forward capacity of the buffer, by default 10MB.
const size_t kForwardCapacity = 10 * kMegabyte;
// The threshold of bytes that we should wait until the data arrives in the
// future instead of restarting a new connection. This number is defined in the
// number of bytes, we should determine this value from typical connection speed
// and amount of time for a suitable wait. Now I just make a guess for this
// number to be 2MB.
// TODO(hclam): determine a better value for this.
const int kForwardWaitThreshold = 2 * kMegabyte;
// Defines how long we should wait for more data before we declare a connection
// timeout and start a new request.
// TODO(hclam): Set it to 5s, calibrate this value later.
const int kTimeoutMilliseconds = 5000;
// Defines how many times we should try to read from a buffered resource loader
// before we declare a read error. After each failure of read from a buffered
// resource loader, a new one is created to be read.
const int kReadTrials = 3;
// BufferedDataSource has an intermediate buffer, this value governs the initial
// size of that buffer. It is set to 32KB because this is a typical read size
// of FFmpeg.
const int kInitialReadBufferSize = 32768;
// Returns true if |url| operates on HTTP protocol.
bool IsHttpProtocol(const GURL& url) {
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),
content_length_(kPositionNotSpecified),
instance_size_(kPositionNotSpecified),
read_callback_(NULL),
read_position_(0),
read_size_(0),
read_buffer_(NULL),
first_offset_(0),
last_offset_(0) {
}
BufferedResourceLoader::~BufferedResourceLoader() {
}
void BufferedResourceLoader::Start(net::CompletionCallback* start_callback,
NetworkEventCallback* event_callback) {
// Make sure we have not started.
DCHECK(!bridge_.get());
DCHECK(!start_callback_.get());
DCHECK(!event_callback_.get());
DCHECK(start_callback);
DCHECK(event_callback);
start_callback_.reset(start_callback);
event_callback_.reset(event_callback);
if (first_byte_position_ != kPositionNotSpecified) {
range_requested_ = true;
// TODO(hclam): server may not support range request so |offset_| may not
// equal to |first_byte_position_|.
offset_ = first_byte_position_;
}
// Creates the bridge on render thread since we can only access
// ResourceDispatcher on this thread.
bridge_.reset(
bridge_factory_->CreateBridge(
url_,
IsMediaCacheEnabled() ? net::LOAD_NORMAL : net::LOAD_BYPASS_CACHE,
first_byte_position_,
last_byte_position_));
// Increment the reference count right before we start the request. This
// reference will be release when this request has ended.
AddRef();
// And start the resource loading.
bridge_->Start(this);
}
void BufferedResourceLoader::Stop() {
// Reset callbacks.
start_callback_.reset();
event_callback_.reset();
read_callback_.reset();
// Use the internal buffer to signal that we have been stopped.
// TODO(hclam): Not so pretty to do this.
if (!buffer_.get())
return;
// Destroy internal buffer.
buffer_.reset();
if (bridge_.get()) {
// Cancel the request. This method call will cancel the request
// asynchronously. We may still get data or messages until we receive
// a response completed message.
if (deferred_)
bridge_->SetDefersLoading(false);
deferred_ = false;
bridge_->Cancel();
}
}
void BufferedResourceLoader::Read(int64 position,
int read_size,
uint8* buffer,
net::CompletionCallback* read_callback) {
DCHECK(!read_callback_.get());
DCHECK(buffer_.get());
DCHECK(read_callback);
DCHECK(buffer);
// Save the parameter of reading.
read_callback_.reset(read_callback);
read_position_ = position;
read_size_ = read_size;
read_buffer_ = buffer;
// If read position is beyond the instance size, we cannot read there.
if (instance_size_ != kPositionNotSpecified &&
instance_size_ <= read_position_) {
DoneRead(0);
return;
}
// Make sure |offset_| and |read_position_| does not differ by a large
// amount.
if (read_position_ > offset_ + kint32max ||
read_position_ < offset_ + kint32min) {
DoneRead(net::ERR_CACHE_MISS);
return;
}
// Prepare the parameters.
first_offset_ = static_cast<int>(read_position_ - offset_);
last_offset_ = first_offset_ + read_size_;
// If we can serve the request now, do the actual read.
if (CanFulfillRead()) {
ReadInternal();
DisableDeferIfNeeded();
return;
}
// If we expected the read request to be fulfilled later, returns
// immediately and let more data to flow in.
if (WillFulfillRead())
return;
// Make a callback to report failure.
DoneRead(net::ERR_CACHE_MISS);
}
int64 BufferedResourceLoader::GetBufferedFirstBytePosition() {
if (buffer_.get())
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::ResourceResponseInfo& info,
bool* has_new_first_party_for_cookies,
GURL* new_first_party_for_cookies) {
DCHECK(bridge_.get());
// Save the new URL.
url_ = new_url;
// TODO(wtc): should we return a new first party for cookies URL?
*has_new_first_party_for_cookies = false;
// The load may have been stopped and |start_callback| is destroyed.
// In this case we shouldn't do anything.
if (!start_callback_.get())
return true;
if (!IsProtocolSupportedForMedia(new_url)) {
DoneStart(net::ERR_ADDRESS_INVALID);
Stop();
return false;
}
return true;
}
void BufferedResourceLoader::OnReceivedResponse(
const webkit_glue::ResourceResponseInfo& info,
bool content_filtered) {
DCHECK(bridge_.get());
// The loader may have been stopped and |start_callback| is destroyed.
// In this case we shouldn't do anything.
if (!start_callback_.get())
return;
// We make a strong assumption that when we reach here we have either
// received a response from HTTP/HTTPS protocol or the request was
// successful (in particular range request). So we only verify the partial
// response for HTTP and HTTPS protocol.
if (IsHttpProtocol(url_)) {
int error = net::OK;
if (!info.headers) {
// We expect to receive headers because this is a HTTP or HTTPS protocol,
// if not report failure.
error = net::ERR_INVALID_RESPONSE;
} else {
if (info.headers->response_code() == kHttpPartialContent)
partial_response_ = true;
if (range_requested_ && partial_response_) {
// If we have verified the partial response and it is correct, we will
// return net::OK.
if (!VerifyPartialResponse(info))
error = net::ERR_INVALID_RESPONSE;
} else if (info.headers->response_code() != kHttpOK) {
// We didn't request a range but server didn't reply with "200 OK".
error = net::ERR_FAILED;
}
}
if (error != net::OK) {
DoneStart(error);
Stop();
return;
}
} else {
// For any protocol other than HTTP and HTTPS, assume range request is
// always fulfilled.
partial_response_ = range_requested_;
}
// |info.content_length| can be -1, in that case |content_length_| is
// not specified and this is a streaming response.
content_length_ = info.content_length;
// If we have not requested a range, then the size of the instance is equal
// to the content length.
if (!partial_response_)
instance_size_ = content_length_;
// Calls with a successful response.
DoneStart(net::OK);
}
void BufferedResourceLoader::OnReceivedData(const char* data, int len) {
DCHECK(bridge_.get());
// If this loader has been stopped, |buffer_| would be destroyed.
// 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(
const URLRequestStatus& status,
const std::string& security_info,
const base::Time& completion_time) {
DCHECK(bridge_.get());
// Saves the information that the request has completed.
completed_ = true;
// If there is a start callback, calls it.
if (start_callback_.get()) {
DoneStart(status.os_error());
}
// If there is a pending read but the request has ended, returns with what
// we have.
if (HasPendingRead()) {
// Make sure we have a valid buffer before we satisfy a read request.
DCHECK(buffer_.get());
if (status.is_success()) {
// Try to fulfill with what is in the buffer.
if (CanFulfillRead())
ReadInternal();
else
DoneRead(net::ERR_CACHE_MISS);
} else {
// If the request has failed, then fail the read.
DoneRead(net::ERR_FAILED);
}
}
// There must not be any outstanding read request.
DCHECK(!HasPendingRead());
// Notify that network response is completed.
NotifyNetworkEvent();
// 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_ &&
(!defer_allowed_ ||
buffer_->forward_bytes() < buffer_->forward_capacity() / 2)) {
deferred_ = false;
if (bridge_.get())
bridge_->SetDefersLoading(false);
NotifyNetworkEvent();
}
}
bool BufferedResourceLoader::CanFulfillRead() {
// If we are reading too far in the backward direction.
if (first_offset_ < 0 &&
first_offset_ + static_cast<int>(buffer_->backward_bytes()) < 0)
return false;
// If the start offset is too far ahead.
if (first_offset_ >= static_cast<int>(buffer_->forward_bytes()))
return false;
// At the point, we verified that first byte requested is within the buffer.
// If the request has completed, then just returns with what we have now.
if (completed_)
return true;
// If the resource request is still active, make sure the whole requested
// range is covered.
if (last_offset_ > static_cast<int>(buffer_->forward_bytes()))
return false;
return true;
}
bool BufferedResourceLoader::WillFulfillRead() {
// Reading too far in the backward direction.
if (first_offset_ < 0 &&
first_offset_ + static_cast<int>(buffer_->backward_bytes()) < 0)
return false;
// Try to read too far ahead.
if (last_offset_ > kForwardWaitThreshold)
return false;
// The resource request has completed, there's no way we can fulfill the
// read request.
if (completed_)
return false;
return true;
}
void BufferedResourceLoader::ReadInternal() {
// Seek to the first byte requested.
bool ret = buffer_->Seek(first_offset_);
DCHECK(ret);
// Then do the read.
int read = static_cast<int>(buffer_->Read(read_buffer_, read_size_));
offset_ += first_offset_ + read;
// And report with what we have read.
DoneRead(read);
}
bool BufferedResourceLoader::VerifyPartialResponse(
const ResourceResponseInfo& info) {
int64 first_byte_position, last_byte_position, instance_size;
if (!info.headers->GetContentRange(&first_byte_position,
&last_byte_position,
&instance_size)) {
return false;
}
if (instance_size != kPositionNotSpecified)
instance_size_ = instance_size;
if (first_byte_position_ != -1 &&
first_byte_position_ != first_byte_position) {
return false;
}
// TODO(hclam): I should also check |last_byte_position|, but since
// we will never make such a request that it is ok to leave it unimplemented.
return true;
}
void BufferedResourceLoader::DoneRead(int error) {
read_callback_->RunWithParams(Tuple1<int>(error));
read_callback_.reset();
read_position_ = 0;
read_size_ = 0;
read_buffer_ = NULL;
first_offset_ = 0;
last_offset_ = 0;
}
void BufferedResourceLoader::DoneStart(int error) {
start_callback_->RunWithParams(Tuple1<int>(error));
start_callback_.reset();
}
void BufferedResourceLoader::NotifyNetworkEvent() {
if (event_callback_.get())
event_callback_->Run();
}
/////////////////////////////////////////////////////////////////////////////
// BufferedDataSource
BufferedDataSource::BufferedDataSource(
MessageLoop* render_loop,
webkit_glue::MediaResourceLoaderBridgeFactory* bridge_factory)
: total_bytes_(kPositionNotSpecified),
loaded_(false),
streaming_(false),
bridge_factory_(bridge_factory),
loader_(NULL),
network_activity_(false),
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),
media_is_paused_(true),
using_range_request_(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) {
DCHECK(MessageLoop::current() == render_loop_);
return new BufferedResourceLoader(bridge_factory_.get(), url_,
first_byte_position,
last_byte_position);
}
// This method simply returns kTimeoutMilliseconds. The purpose of this
// method is to be overidded so as to provide a different timeout value
// for testing purpose.
base::TimeDelta BufferedDataSource::GetTimeoutMilliseconds() {
return base::TimeDelta::FromMilliseconds(kTimeoutMilliseconds);
}
/////////////////////////////////////////////////////////////////////////////
// BufferedDataSource, media::MediaFilter implementation
void BufferedDataSource::Initialize(const std::string& url,
media::FilterCallback* callback) {
// Saves the url.
url_ = GURL(url);
if (!IsProtocolSupportedForMedia(url_)) {
// This method is called on the thread where host() lives so it is safe
// to make this call.
host()->SetError(media::PIPELINE_ERROR_NETWORK);
callback->Run();
delete callback;
return;
}
DCHECK(callback);
initialize_callback_.reset(callback);
media_format_.SetAsString(media::MediaFormat::kMimeType,
media::mime_type::kApplicationOctetStream);
media_format_.SetAsString(media::MediaFormat::kURL, url);
// Post a task to complete the initialization task.
render_loop_->PostTask(FROM_HERE,
NewRunnableMethod(this, &BufferedDataSource::InitializeTask));
}
bool BufferedDataSource::IsUrlSupported(const std::string& url) {
GURL gurl(url);
// This data source doesn't support data:// protocol so reject it.
return IsProtocolSupportedForMedia(gurl) && !IsDataProtocol(gurl);
}
void BufferedDataSource::Stop(media::FilterCallback* callback) {
{
AutoLock auto_lock(lock_);
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) {
if (total_bytes_ != kPositionNotSpecified) {
*size_out = total_bytes_;
return true;
}
*size_out = 0;
return false;
}
bool BufferedDataSource::IsStreaming() {
return streaming_;
}
void BufferedDataSource::Abort() {
DCHECK(MessageLoop::current() == render_loop_);
// If we are told to abort, immediately return from any pending read
// with an error.
if (read_callback_.get()) {
{
AutoLock auto_lock(lock_);
DoneRead_Locked(net::ERR_FAILED);
}
CleanupTask();
}
}
/////////////////////////////////////////////////////////////////////////////
// BufferedDataSource, render thread tasks
void BufferedDataSource::InitializeTask() {
DCHECK(MessageLoop::current() == render_loop_);
DCHECK(!loader_.get());
DCHECK(!stopped_on_render_loop_);
// Kick starts the watch dog task that will handle connection timeout.
// We run the watch dog 2 times faster the actual timeout so as to catch
// the timeout more accurately.
watch_dog_timer_.Start(
GetTimeoutMilliseconds() / 2,
this,
&BufferedDataSource::WatchDogTask);
if (IsHttpProtocol(url_)) {
// Fetch only first 1024 bytes as this usually covers the header portion
// of a media file that gives enough information about the codecs, etc.
// This also serve as a probe to determine server capability to serve
// range request.
// TODO(hclam): Do some experiments for the best approach.
loader_ = CreateResourceLoader(0, 1024);
loader_->Start(
NewCallback(this, &BufferedDataSource::HttpInitialStartCallback),
NewCallback(this, &BufferedDataSource::NetworkEventCallback));
} else {
// For all other protocols, assume they support range request. We fetch
// the full range of the resource to obtain the instance size because
// we won't be served HTTP headers.
loader_ = CreateResourceLoader(-1, -1);
loader_->Start(
NewCallback(this, &BufferedDataSource::NonHttpInitialStartCallback),
NewCallback(this, &BufferedDataSource::NetworkEventCallback));
}
}
void BufferedDataSource::ReadTask(
int64 position, int read_size, uint8* buffer,
media::DataSource::ReadCallback* read_callback) {
DCHECK(MessageLoop::current() == render_loop_);
// If CleanupTask() was executed we should return immediately. We check this
// variable to prevent doing any actual work after clean up was done. We do
// not check |stop_signal_received_| because anything use of it has to be
// within |lock_| which is not desirable.
if (stopped_on_render_loop_)
return;
DCHECK(!read_callback_.get());
DCHECK(read_callback);
// Saves the read parameters.
read_position_ = position;
read_size_ = read_size;
read_callback_.reset(read_callback);
read_buffer_ = buffer;
read_submitted_time_ = base::Time::Now();
read_attempts_ = 0;
// Call to read internal to perform the actual read.
ReadInternal();
}
void BufferedDataSource::CleanupTask() {
DCHECK(MessageLoop::current() == render_loop_);
// If we have already stopped, do nothing.
if (stopped_on_render_loop_)
return;
// Stop the watch dog.
watch_dog_timer_.Stop();
// We just need to stop the loader, so it stops activity.
if (loader_.get())
loader_->Stop();
// Reset the parameters of the current read request.
read_callback_.reset();
read_position_ = 0;
read_size_ = 0;
read_buffer_ = 0;
read_submitted_time_ = base::Time();
read_attempts_ = 0;
// Signal that stop task has finished execution.
stopped_on_render_loop_ = true;
}
void BufferedDataSource::RestartLoadingTask() {
DCHECK(MessageLoop::current() == render_loop_);
// This variable is set in CleanupTask(). We check this and do an early
// return. The sequence of actions which enable this conditions is:
// 1. Stop() is called from the pipeline.
// 2. ReadCallback() is called from the resource loader.
// 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.
if (!read_callback_.get())
return;
DCHECK(loader_.get());
base::TimeDelta delta = base::Time::Now() - read_submitted_time_;
if (delta < GetTimeoutMilliseconds())
return;
// TODO(hclam): Maybe raise an error here. But if an error is reported
// the whole pipeline may get destroyed...
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_]);
}
// Perform the actual read with BufferedResourceLoader.
loader_->Read(read_position_, read_size_, intermediate_read_buffer_.get(),
NewCallback(this, &BufferedDataSource::ReadCallback));
}
// Method to report the results of the current read request. Also reset all
// the read parameters.
void BufferedDataSource::DoneRead_Locked(int error) {
DCHECK(MessageLoop::current() == render_loop_);
DCHECK(read_callback_.get());
lock_.AssertAcquired();
if (error >= 0) {
read_callback_->RunWithParams(Tuple1<size_t>(error));
} else {
read_callback_->RunWithParams(
Tuple1<size_t>(static_cast<size_t>(media::DataSource::kReadError)));
}
read_callback_.reset();
read_position_ = 0;
read_size_ = 0;
read_buffer_ = 0;
}
void BufferedDataSource::DoneInitialization_Locked() {
DCHECK(MessageLoop::current() == render_loop_);
DCHECK(initialize_callback_.get());
lock_.AssertAcquired();
initialize_callback_->Run();
initialize_callback_.reset();
}
/////////////////////////////////////////////////////////////////////////////
// BufferedDataSource, callback methods.
// These methods are called on the render thread for the events reported by
// BufferedResourceLoader.
void BufferedDataSource::HttpInitialStartCallback(int error) {
DCHECK(MessageLoop::current() == render_loop_);
DCHECK(loader_.get());
int64 instance_size = loader_->instance_size();
bool partial_response = loader_->partial_response();
bool success = error == net::OK;
if (success) {
// TODO(hclam): Needs more thinking about supporting servers without range
// request or their partial response is not complete.
total_bytes_ = instance_size;
loaded_ = false;
streaming_ = (instance_size == kPositionNotSpecified) || !partial_response;
} else {
// TODO(hclam): In case of failure, we can retry several times.
loader_->Stop();
}
if (error == net::ERR_INVALID_RESPONSE && using_range_request_) {
// Assuming that the Range header was causing the problem. Retry without
// the Range header.
using_range_request_ = false;
loader_ = CreateResourceLoader(-1, -1);
loader_->Start(
NewCallback(this, &BufferedDataSource::HttpInitialStartCallback),
NewCallback(this, &BufferedDataSource::NetworkEventCallback));
return;
}
// We need to prevent calling to filter host and running the callback if
// we have received the stop signal. We need to lock down the whole callback
// method to prevent bad things from happening. The reason behind this is
// that we cannot guarantee tasks on render thread have completely stopped
// when we receive the Stop() method call. The only way to solve this is to
// let tasks on render thread to run but make sure they don't call outside
// this object when Stop() method is ever called. Locking this method is safe
// because |lock_| is only acquired in tasks on render thread.
AutoLock auto_lock(lock_);
if (stop_signal_received_)
return;
if (!success) {
host()->SetError(media::PIPELINE_ERROR_NETWORK);
DoneInitialization_Locked();
return;
}
if (streaming_) {
// If the server didn't reply with an instance size, it is likely this
// is a streaming response.
host()->SetStreaming(true);
} else {
// This value governs the range that we can seek to.
// TODO(hclam): Report the correct value of buffered bytes.
host()->SetTotalBytes(total_bytes_);
host()->SetBufferedBytes(0);
}
// Currently, only files can be used reliably w/o a network.
host()->SetLoaded(false);
DoneInitialization_Locked();
}
void BufferedDataSource::NonHttpInitialStartCallback(int error) {
DCHECK(MessageLoop::current() == render_loop_);
DCHECK(loader_.get());
int64 instance_size = loader_->instance_size();
bool success = error == net::OK && instance_size != kPositionNotSpecified;
if (success) {
total_bytes_ = instance_size;
loaded_ = true;
} else {
loader_->Stop();
}
// We need to prevent calling to filter host and running the callback if
// we have received the stop signal. We need to lock down the whole callback
// method to prevent bad things from happening. The reason behind this is
// that we cannot guarantee tasks on render thread have completely stopped
// when we receive the Stop() method call. The only way to solve this is to
// let tasks on render thread to run but make sure they don't call outside
// this object when Stop() method is ever called. Locking this method is safe
// because |lock_| is only acquired in tasks on render thread.
AutoLock auto_lock(lock_);
if (stop_signal_received_)
return;
if (success) {
host()->SetTotalBytes(total_bytes_);
host()->SetBufferedBytes(total_bytes_);
host()->SetLoaded(loaded_);
} else {
host()->SetError(media::PIPELINE_ERROR_NETWORK);
}
DoneInitialization_Locked();
}
void BufferedDataSource::PartialReadStartCallback(int error) {
DCHECK(MessageLoop::current() == render_loop_);
DCHECK(loader_.get());
// This callback method is invoked after we have verified the server has
// range request capability, so as a safety guard verify again the response
// is partial.
if (error == net::OK && loader_->partial_response()) {
// Once the range request has started successfully, we can proceed with
// reading from it.
ReadInternal();
return;
}
// Stop the resource loader since we have received an error.
loader_->Stop();
// We need to prevent calling to filter host and running the callback if
// we have received the stop signal. We need to lock down the whole callback
// method to prevent bad things from happening. The reason behind this is
// that we cannot guarantee tasks on render thread have completely stopped
// when we receive the Stop() method call. So only way to solve this is to
// let tasks on render thread to run but make sure they don't call outside
// this object when Stop() method is ever called. Locking this method is
// safe because |lock_| is only acquired in tasks on render thread.
AutoLock auto_lock(lock_);
if (stop_signal_received_)
return;
DoneRead_Locked(net::ERR_INVALID_RESPONSE);
}
void BufferedDataSource::ReadCallback(int error) {
DCHECK(MessageLoop::current() == render_loop_);
if (error < 0) {
DCHECK(loader_.get());
// Stop the resource load if it failed.
loader_->Stop();
if (error == net::ERR_CACHE_MISS) {
render_loop_->PostTask(FROM_HERE,
NewRunnableMethod(this, &BufferedDataSource::RestartLoadingTask));
return;
}
}
// We need to prevent calling to filter host and running the callback if
// we have received the stop signal. We need to lock down the whole callback
// method to prevent bad things from happening. The reason behind this is
// that we cannot guarantee tasks on render thread have completely stopped
// when we receive the Stop() method call. So only way to solve this is to
// let tasks on render thread to run but make sure they don't call outside
// this object when Stop() method is ever called. Locking this method is safe
// because |lock_| is only acquired in tasks on render thread.
AutoLock auto_lock(lock_);
if (stop_signal_received_)
return;
if (error > 0) {
// If a position error code is received, read was successful. So copy
// from intermediate read buffer to the target read buffer.
memcpy(read_buffer_, intermediate_read_buffer_.get(), error);
}
DoneRead_Locked(error);
}
void BufferedDataSource::NetworkEventCallback() {
DCHECK(MessageLoop::current() == render_loop_);
DCHECK(loader_.get());
// In case of non-HTTP request we don't need to report network events,
// so return immediately.
if (loaded_)
return;
bool network_activity = loader_->network_activity();
int64 buffered_last_byte_position = loader_->GetBufferedLastBytePosition();
// If we get an unspecified value, return immediately.
if (buffered_last_byte_position == kPositionNotSpecified)
return;
// We need to prevent calling to filter host and running the callback if
// we have received the stop signal. We need to lock down the whole callback
// method to prevent bad things from happening. The reason behind this is
// that we cannot guarantee tasks on render thread have completely stopped
// when we receive the Stop() method call. So only way to solve this is to
// let tasks on render thread to run but make sure they don't call outside
// this object when Stop() method is ever called. Locking this method is safe
// because |lock_| is only acquired in tasks on render thread.
AutoLock auto_lock(lock_);
if (stop_signal_received_)
return;
if (network_activity != network_activity_) {
network_activity_ = network_activity;
host()->SetNetworkActivity(network_activity);
}
host()->SetBufferedBytes(buffered_last_byte_position + 1);
}
} // namespace webkit_glue
|