src/net/url_request/url_fetcher_core.cc

   1 // Copyright (c) 2012 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 #include "net/url_request/url_fetcher_core.h"
   6
   7 #include <stdint.h>
   8
   9 #include "base/bind.h"
  10 #include "base/logging.h"
  11 #include "base/metrics/histogram.h"
  12 #include "base/sequenced_task_runner.h"
  13 #include "base/single_thread_task_runner.h"
  14 #include "base/stl_util.h"
  15 #include "base/thread_task_runner_handle.h"
  16 #include "base/tracked_objects.h"
  17 #include "net/base/elements_upload_data_stream.h"
  18 #include "net/base/io_buffer.h"
  19 #include "net/base/load_flags.h"
  20 #include "net/base/net_errors.h"
  21 #include "net/base/request_priority.h"
  22 #include "net/base/upload_bytes_element_reader.h"
  23 #include "net/base/upload_data_stream.h"
  24 #include "net/base/upload_file_element_reader.h"
  25 #include "net/http/http_response_headers.h"
  26 #include "net/url_request/redirect_info.h"
  27 #include "net/url_request/url_fetcher_delegate.h"
  28 #include "net/url_request/url_fetcher_response_writer.h"
  29 #include "net/url_request/url_request_context.h"
  30 #include "net/url_request/url_request_context_getter.h"
  31 #include "net/url_request/url_request_throttler_manager.h"
  32
  33 namespace {
  34
  35 const int kBufferSize = 4096;
  36 const int kUploadProgressTimerInterval = 100;
  37 bool g_interception_enabled = false;
  38 bool g_ignore_certificate_requests = false;
  39
  40 void EmptyCompletionCallback(int result) {}
  41
  42 }  // namespace
  43
  44 namespace net {
  45
  46 // URLFetcherCore::Registry ---------------------------------------------------
  47
  48 URLFetcherCore::Registry::Registry() {}
  49 URLFetcherCore::Registry::~Registry() {}
  50
  51 void URLFetcherCore::Registry::AddURLFetcherCore(URLFetcherCore* core) {
  52   DCHECK(!ContainsKey(fetchers_, core));
  53   fetchers_.insert(core);
  54 }
  55
  56 void URLFetcherCore::Registry::RemoveURLFetcherCore(URLFetcherCore* core) {
  57   DCHECK(ContainsKey(fetchers_, core));
  58   fetchers_.erase(core);
  59 }
  60
  61 void URLFetcherCore::Registry::CancelAll() {
  62   while (!fetchers_.empty())
  63     (*fetchers_.begin())->CancelURLRequest(ERR_ABORTED);
  64 }
  65
  66 // URLFetcherCore -------------------------------------------------------------
  67
  68 // static
  69 base::LazyInstance<URLFetcherCore::Registry>
  70     URLFetcherCore::g_registry = LAZY_INSTANCE_INITIALIZER;
  71
  72 URLFetcherCore::URLFetcherCore(URLFetcher* fetcher,
  73                                const GURL& original_url,
  74                                URLFetcher::RequestType request_type,
  75                                URLFetcherDelegate* d)
  76     : fetcher_(fetcher),
  77       original_url_(original_url),
  78       request_type_(request_type),
  79       delegate_(d),
  80       delegate_task_runner_(base::ThreadTaskRunnerHandle::Get()),
  81       load_flags_(LOAD_NORMAL),
  82       response_code_(URLFetcher::RESPONSE_CODE_INVALID),
  83       buffer_(new IOBuffer(kBufferSize)),
  84       url_request_data_key_(NULL),
  85       was_fetched_via_proxy_(false),
  86       upload_content_set_(false),
  87       upload_range_offset_(0),
  88       upload_range_length_(0),
  89       referrer_policy_(
  90           URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE),
  91       is_chunked_upload_(false),
  92       was_cancelled_(false),
  93       stop_on_redirect_(false),
  94       stopped_on_redirect_(false),
  95       automatically_retry_on_5xx_(true),
  96       num_retries_on_5xx_(0),
  97       max_retries_on_5xx_(0),
  98       num_retries_on_network_changes_(0),
  99       max_retries_on_network_changes_(0),
 100       current_upload_bytes_(-1),
 101       current_response_bytes_(0),
 102       total_response_bytes_(-1) {
 103   CHECK(original_url_.is_valid());
 104 }
 105
 106 void URLFetcherCore::Start() {
 107   DCHECK(delegate_task_runner_.get());
 108   DCHECK(request_context_getter_.get()) << "We need an URLRequestContext!";
 109   if (network_task_runner_.get()) {
 110     DCHECK_EQ(network_task_runner_,
 111               request_context_getter_->GetNetworkTaskRunner());
 112   } else {
 113     network_task_runner_ = request_context_getter_->GetNetworkTaskRunner();
 114   }
 115   DCHECK(network_task_runner_.get()) << "We need an IO task runner";
 116
 117   network_task_runner_->PostTask(
 118       FROM_HERE, base::Bind(&URLFetcherCore::StartOnIOThread, this));
 119 }
 120
 121 void URLFetcherCore::Stop() {
 122   if (delegate_task_runner_.get())  // May be NULL in tests.
 123     DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 124
 125   delegate_ = NULL;
 126   fetcher_ = NULL;
 127   if (!network_task_runner_.get())
 128     return;
 129   if (network_task_runner_->RunsTasksOnCurrentThread()) {
 130     CancelURLRequest(ERR_ABORTED);
 131   } else {
 132     network_task_runner_->PostTask(
 133         FROM_HERE,
 134         base::Bind(&URLFetcherCore::CancelURLRequest, this, ERR_ABORTED));
 135   }
 136 }
 137
 138 void URLFetcherCore::SetUploadData(const std::string& upload_content_type,
 139                                    const std::string& upload_content) {
 140   DCHECK(!is_chunked_upload_);
 141   DCHECK(!upload_content_set_);
 142   DCHECK(upload_content_.empty());
 143   DCHECK(upload_file_path_.empty());
 144   DCHECK(upload_content_type_.empty());
 145
 146   // Empty |upload_content_type| is allowed iff the |upload_content| is empty.
 147   DCHECK(upload_content.empty() || !upload_content_type.empty());
 148
 149   upload_content_type_ = upload_content_type;
 150   upload_content_ = upload_content;
 151   upload_content_set_ = true;
 152 }
 153
 154 void URLFetcherCore::SetUploadFilePath(
 155     const std::string& upload_content_type,
 156     const base::FilePath& file_path,
 157     uint64 range_offset,
 158     uint64 range_length,
 159     scoped_refptr<base::TaskRunner> file_task_runner) {
 160   DCHECK(!is_chunked_upload_);
 161   DCHECK(!upload_content_set_);
 162   DCHECK(upload_content_.empty());
 163   DCHECK(upload_file_path_.empty());
 164   DCHECK_EQ(upload_range_offset_, 0ULL);
 165   DCHECK_EQ(upload_range_length_, 0ULL);
 166   DCHECK(upload_content_type_.empty());
 167   DCHECK(!upload_content_type.empty());
 168
 169   upload_content_type_ = upload_content_type;
 170   upload_file_path_ = file_path;
 171   upload_range_offset_ = range_offset;
 172   upload_range_length_ = range_length;
 173   upload_file_task_runner_ = file_task_runner;
 174   upload_content_set_ = true;
 175 }
 176
 177 void URLFetcherCore::SetChunkedUpload(const std::string& content_type) {
 178   DCHECK(is_chunked_upload_ ||
 179          (upload_content_type_.empty() &&
 180           upload_content_.empty()));
 181
 182   // Empty |content_type| is not allowed here, because it is impossible
 183   // to ensure non-empty upload content as it is not yet supplied.
 184   DCHECK(!content_type.empty());
 185
 186   upload_content_type_ = content_type;
 187   upload_content_.clear();
 188   is_chunked_upload_ = true;
 189 }
 190
 191 void URLFetcherCore::AppendChunkToUpload(const std::string& content,
 192                                          bool is_last_chunk) {
 193   DCHECK(delegate_task_runner_.get());
 194   DCHECK(network_task_runner_.get());
 195   network_task_runner_->PostTask(
 196       FROM_HERE,
 197       base::Bind(&URLFetcherCore::CompleteAddingUploadDataChunk, this, content,
 198                  is_last_chunk));
 199 }
 200
 201 void URLFetcherCore::SetLoadFlags(int load_flags) {
 202   load_flags_ = load_flags;
 203 }
 204
 205 int URLFetcherCore::GetLoadFlags() const {
 206   return load_flags_;
 207 }
 208
 209 void URLFetcherCore::SetReferrer(const std::string& referrer) {
 210   referrer_ = referrer;
 211 }
 212
 213 void URLFetcherCore::SetReferrerPolicy(
 214     URLRequest::ReferrerPolicy referrer_policy) {
 215   referrer_policy_ = referrer_policy;
 216 }
 217
 218 void URLFetcherCore::SetExtraRequestHeaders(
 219     const std::string& extra_request_headers) {
 220   extra_request_headers_.Clear();
 221   extra_request_headers_.AddHeadersFromString(extra_request_headers);
 222 }
 223
 224 void URLFetcherCore::AddExtraRequestHeader(const std::string& header_line) {
 225   extra_request_headers_.AddHeaderFromString(header_line);
 226 }
 227
 228 void URLFetcherCore::SetRequestContext(
 229     URLRequestContextGetter* request_context_getter) {
 230   DCHECK(!request_context_getter_.get());
 231   DCHECK(request_context_getter);
 232   request_context_getter_ = request_context_getter;
 233 }
 234
 235 void URLFetcherCore::SetFirstPartyForCookies(
 236     const GURL& first_party_for_cookies) {
 237   DCHECK(first_party_for_cookies_.is_empty());
 238   first_party_for_cookies_ = first_party_for_cookies;
 239 }
 240
 241 void URLFetcherCore::SetURLRequestUserData(
 242     const void* key,
 243     const URLFetcher::CreateDataCallback& create_data_callback) {
 244   DCHECK(key);
 245   DCHECK(!create_data_callback.is_null());
 246   url_request_data_key_ = key;
 247   url_request_create_data_callback_ = create_data_callback;
 248 }
 249
 250 void URLFetcherCore::SetStopOnRedirect(bool stop_on_redirect) {
 251   stop_on_redirect_ = stop_on_redirect;
 252 }
 253
 254 void URLFetcherCore::SetAutomaticallyRetryOn5xx(bool retry) {
 255   automatically_retry_on_5xx_ = retry;
 256 }
 257
 258 void URLFetcherCore::SetMaxRetriesOn5xx(int max_retries) {
 259   max_retries_on_5xx_ = max_retries;
 260 }
 261
 262 int URLFetcherCore::GetMaxRetriesOn5xx() const {
 263   return max_retries_on_5xx_;
 264 }
 265
 266 base::TimeDelta URLFetcherCore::GetBackoffDelay() const {
 267   return backoff_delay_;
 268 }
 269
 270 void URLFetcherCore::SetAutomaticallyRetryOnNetworkChanges(int max_retries) {
 271   max_retries_on_network_changes_ = max_retries;
 272 }
 273
 274 void URLFetcherCore::SaveResponseToFileAtPath(
 275     const base::FilePath& file_path,
 276     scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
 277   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 278   SaveResponseWithWriter(scoped_ptr<URLFetcherResponseWriter>(
 279       new URLFetcherFileWriter(file_task_runner, file_path)));
 280 }
 281
 282 void URLFetcherCore::SaveResponseToTemporaryFile(
 283     scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
 284   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 285   SaveResponseWithWriter(scoped_ptr<URLFetcherResponseWriter>(
 286       new URLFetcherFileWriter(file_task_runner, base::FilePath())));
 287 }
 288
 289 void URLFetcherCore::SaveResponseWithWriter(
 290     scoped_ptr<URLFetcherResponseWriter> response_writer) {
 291   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 292   response_writer_ = response_writer.Pass();
 293 }
 294
 295 HttpResponseHeaders* URLFetcherCore::GetResponseHeaders() const {
 296   return response_headers_.get();
 297 }
 298
 299 // TODO(panayiotis): socket_address_ is written in the IO thread,
 300 // if this is accessed in the UI thread, this could result in a race.
 301 // Same for response_headers_ above and was_fetched_via_proxy_ below.
 302 HostPortPair URLFetcherCore::GetSocketAddress() const {
 303   return socket_address_;
 304 }
 305
 306 bool URLFetcherCore::WasFetchedViaProxy() const {
 307   return was_fetched_via_proxy_;
 308 }
 309
 310 const GURL& URLFetcherCore::GetOriginalURL() const {
 311   return original_url_;
 312 }
 313
 314 const GURL& URLFetcherCore::GetURL() const {
 315   return url_;
 316 }
 317
 318 const URLRequestStatus& URLFetcherCore::GetStatus() const {
 319   return status_;
 320 }
 321
 322 int URLFetcherCore::GetResponseCode() const {
 323   return response_code_;
 324 }
 325
 326 const ResponseCookies& URLFetcherCore::GetCookies() const {
 327   return cookies_;
 328 }
 329
 330 void URLFetcherCore::ReceivedContentWasMalformed() {
 331   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 332   if (network_task_runner_.get()) {
 333     network_task_runner_->PostTask(
 334         FROM_HERE, base::Bind(&URLFetcherCore::NotifyMalformedContent, this));
 335   }
 336 }
 337
 338 bool URLFetcherCore::GetResponseAsString(
 339     std::string* out_response_string) const {
 340   URLFetcherStringWriter* string_writer =
 341       response_writer_ ? response_writer_->AsStringWriter() : NULL;
 342   if (!string_writer)
 343     return false;
 344
 345   *out_response_string = string_writer->data();
 346   UMA_HISTOGRAM_MEMORY_KB("UrlFetcher.StringResponseSize",
 347                           (string_writer->data().length() / 1024));
 348   return true;
 349 }
 350
 351 bool URLFetcherCore::GetResponseAsFilePath(bool take_ownership,
 352                                            base::FilePath* out_response_path) {
 353   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 354
 355   URLFetcherFileWriter* file_writer =
 356       response_writer_ ? response_writer_->AsFileWriter() : NULL;
 357   if (!file_writer)
 358     return false;
 359
 360   *out_response_path = file_writer->file_path();
 361
 362   if (take_ownership) {
 363     // Intentionally calling a file_writer_ method directly without posting
 364     // the task to network_task_runner_.
 365     //
 366     // This is for correctly handling the case when file_writer_->DisownFile()
 367     // is soon followed by URLFetcherCore::Stop(). We have to make sure that
 368     // DisownFile takes effect before Stop deletes file_writer_.
 369     //
 370     // This direct call should be thread-safe, since DisownFile itself does no
 371     // file operation. It just flips the state to be referred in destruction.
 372     file_writer->DisownFile();
 373   }
 374   return true;
 375 }
 376
 377 void URLFetcherCore::OnReceivedRedirect(URLRequest* request,
 378                                         const RedirectInfo& redirect_info,
 379                                         bool* defer_redirect) {
 380   DCHECK_EQ(request, request_.get());
 381   DCHECK(network_task_runner_->BelongsToCurrentThread());
 382   if (stop_on_redirect_) {
 383     stopped_on_redirect_ = true;
 384     url_ = redirect_info.new_url;
 385     response_code_ = request_->GetResponseCode();
 386     was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
 387     request->Cancel();
 388     OnReadCompleted(request, 0);
 389   }
 390 }
 391
 392 void URLFetcherCore::OnResponseStarted(URLRequest* request) {
 393   DCHECK_EQ(request, request_.get());
 394   DCHECK(network_task_runner_->BelongsToCurrentThread());
 395   if (request_->status().is_success()) {
 396     response_code_ = request_->GetResponseCode();
 397     response_headers_ = request_->response_headers();
 398     socket_address_ = request_->GetSocketAddress();
 399     was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
 400     total_response_bytes_ = request_->GetExpectedContentSize();
 401   }
 402
 403   ReadResponse();
 404 }
 405
 406 void URLFetcherCore::OnCertificateRequested(
 407     URLRequest* request,
 408     SSLCertRequestInfo* cert_request_info) {
 409   DCHECK_EQ(request, request_.get());
 410   DCHECK(network_task_runner_->BelongsToCurrentThread());
 411
 412   if (g_ignore_certificate_requests) {
 413     request->ContinueWithCertificate(NULL);
 414   } else {
 415     request->Cancel();
 416   }
 417 }
 418
 419 void URLFetcherCore::OnReadCompleted(URLRequest* request,
 420                                      int bytes_read) {
 421   DCHECK(request == request_);
 422   DCHECK(network_task_runner_->BelongsToCurrentThread());
 423
 424   if (!stopped_on_redirect_)
 425     url_ = request->url();
 426   URLRequestThrottlerManager* throttler_manager =
 427       request->context()->throttler_manager();
 428   if (throttler_manager) {
 429     url_throttler_entry_ = throttler_manager->RegisterRequestUrl(url_);
 430   }
 431
 432   do {
 433     if (!request_->status().is_success() || bytes_read <= 0)
 434       break;
 435
 436     current_response_bytes_ += bytes_read;
 437     InformDelegateDownloadProgress();
 438
 439     const int result =
 440         WriteBuffer(new DrainableIOBuffer(buffer_.get(), bytes_read));
 441     if (result < 0) {
 442       // Write failed or waiting for write completion.
 443       return;
 444     }
 445   } while (request_->Read(buffer_.get(), kBufferSize, &bytes_read));
 446
 447   const URLRequestStatus status = request_->status();
 448
 449   if (status.is_success())
 450     request_->GetResponseCookies(&cookies_);
 451
 452   // See comments re: HEAD requests in ReadResponse().
 453   if (!status.is_io_pending() || request_type_ == URLFetcher::HEAD) {
 454     status_ = status;
 455     ReleaseRequest();
 456
 457     // No more data to write.
 458     const int result = response_writer_->Finish(
 459         base::Bind(&URLFetcherCore::DidFinishWriting, this));
 460     if (result != ERR_IO_PENDING)
 461       DidFinishWriting(result);
 462   }
 463 }
 464
 465 void URLFetcherCore::CancelAll() {
 466   g_registry.Get().CancelAll();
 467 }
 468
 469 int URLFetcherCore::GetNumFetcherCores() {
 470   return g_registry.Get().size();
 471 }
 472
 473 void URLFetcherCore::SetEnableInterceptionForTests(bool enabled) {
 474   g_interception_enabled = enabled;
 475 }
 476
 477 void URLFetcherCore::SetIgnoreCertificateRequests(bool ignored) {
 478   g_ignore_certificate_requests = ignored;
 479 }
 480
 481 URLFetcherCore::~URLFetcherCore() {
 482   // |request_| should be NULL. If not, it's unsafe to delete it here since we
 483   // may not be on the IO thread.
 484   DCHECK(!request_.get());
 485 }
 486
 487 void URLFetcherCore::StartOnIOThread() {
 488   DCHECK(network_task_runner_->BelongsToCurrentThread());
 489
 490   if (!response_writer_)
 491     response_writer_.reset(new URLFetcherStringWriter);
 492
 493   const int result = response_writer_->Initialize(
 494       base::Bind(&URLFetcherCore::DidInitializeWriter, this));
 495   if (result != ERR_IO_PENDING)
 496     DidInitializeWriter(result);
 497 }
 498
 499 void URLFetcherCore::StartURLRequest() {
 500   DCHECK(network_task_runner_->BelongsToCurrentThread());
 501
 502   if (was_cancelled_) {
 503     // Since StartURLRequest() is posted as a *delayed* task, it may
 504     // run after the URLFetcher was already stopped.
 505     return;
 506   }
 507
 508   DCHECK(request_context_getter_.get());
 509   DCHECK(!request_.get());
 510
 511   g_registry.Get().AddURLFetcherCore(this);
 512   current_response_bytes_ = 0;
 513   request_ = request_context_getter_->GetURLRequestContext()->CreateRequest(
 514       original_url_, DEFAULT_PRIORITY, this, NULL);
 515   request_->set_stack_trace(stack_trace_);
 516   int flags = request_->load_flags() | load_flags_;
 517   if (!g_interception_enabled)
 518     flags = flags | LOAD_DISABLE_INTERCEPT;
 519
 520   if (is_chunked_upload_)
 521     request_->EnableChunkedUpload();
 522   request_->SetLoadFlags(flags);
 523   request_->SetReferrer(referrer_);
 524   request_->set_referrer_policy(referrer_policy_);
 525   request_->set_first_party_for_cookies(first_party_for_cookies_.is_empty() ?
 526       original_url_ : first_party_for_cookies_);
 527   if (url_request_data_key_ && !url_request_create_data_callback_.is_null()) {
 528     request_->SetUserData(url_request_data_key_,
 529                           url_request_create_data_callback_.Run());
 530   }
 531
 532   switch (request_type_) {
 533     case URLFetcher::GET:
 534       break;
 535
 536     case URLFetcher::POST:
 537     case URLFetcher::PUT:
 538     case URLFetcher::PATCH:
 539       // Upload content must be set.
 540       DCHECK(is_chunked_upload_ || upload_content_set_);
 541
 542       request_->set_method(
 543           request_type_ == URLFetcher::POST ? "POST" :
 544           request_type_ == URLFetcher::PUT ? "PUT" : "PATCH");
 545       if (!upload_content_type_.empty()) {
 546         extra_request_headers_.SetHeader(HttpRequestHeaders::kContentType,
 547                                          upload_content_type_);
 548       }
 549       if (!upload_content_.empty()) {
 550         scoped_ptr<UploadElementReader> reader(new UploadBytesElementReader(
 551             upload_content_.data(), upload_content_.size()));
 552         request_->set_upload(
 553             ElementsUploadDataStream::CreateWithReader(reader.Pass(), 0));
 554       } else if (!upload_file_path_.empty()) {
 555         scoped_ptr<UploadElementReader> reader(
 556             new UploadFileElementReader(upload_file_task_runner_.get(),
 557                                         upload_file_path_,
 558                                         upload_range_offset_,
 559                                         upload_range_length_,
 560                                         base::Time()));
 561         request_->set_upload(
 562             ElementsUploadDataStream::CreateWithReader(reader.Pass(), 0));
 563       }
 564
 565       current_upload_bytes_ = -1;
 566       // TODO(kinaba): http://crbug.com/118103. Implement upload callback in the
 567       //  layer and avoid using timer here.
 568       upload_progress_checker_timer_.reset(
 569           new base::RepeatingTimer<URLFetcherCore>());
 570       upload_progress_checker_timer_->Start(
 571           FROM_HERE,
 572           base::TimeDelta::FromMilliseconds(kUploadProgressTimerInterval),
 573           this,
 574           &URLFetcherCore::InformDelegateUploadProgress);
 575       break;
 576
 577     case URLFetcher::HEAD:
 578       request_->set_method("HEAD");
 579       break;
 580
 581     case URLFetcher::DELETE_REQUEST:
 582       request_->set_method("DELETE");
 583       break;
 584
 585     default:
 586       NOTREACHED();
 587   }
 588
 589   if (!extra_request_headers_.IsEmpty())
 590     request_->SetExtraRequestHeaders(extra_request_headers_);
 591
 592   request_->Start();
 593 }
 594
 595 void URLFetcherCore::DidInitializeWriter(int result) {
 596   if (result != OK) {
 597     CancelURLRequest(result);
 598     delegate_task_runner_->PostTask(
 599         FROM_HERE,
 600         base::Bind(&URLFetcherCore::InformDelegateFetchIsComplete, this));
 601     return;
 602   }
 603   StartURLRequestWhenAppropriate();
 604 }
 605
 606 void URLFetcherCore::StartURLRequestWhenAppropriate() {
 607   DCHECK(network_task_runner_->BelongsToCurrentThread());
 608
 609   if (was_cancelled_)
 610     return;
 611
 612   DCHECK(request_context_getter_.get());
 613
 614   int64 delay = INT64_C(0);
 615   if (!original_url_throttler_entry_.get()) {
 616     URLRequestThrottlerManager* manager =
 617         request_context_getter_->GetURLRequestContext()->throttler_manager();
 618     if (manager) {
 619       original_url_throttler_entry_ =
 620           manager->RegisterRequestUrl(original_url_);
 621     }
 622   }
 623   if (original_url_throttler_entry_.get()) {
 624     delay = original_url_throttler_entry_->ReserveSendingTimeForNextRequest(
 625         GetBackoffReleaseTime());
 626   }
 627
 628   if (delay == INT64_C(0)) {
 629     StartURLRequest();
 630   } else {
 631     base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
 632         FROM_HERE, base::Bind(&URLFetcherCore::StartURLRequest, this),
 633         base::TimeDelta::FromMilliseconds(delay));
 634   }
 635 }
 636
 637 void URLFetcherCore::CancelURLRequest(int error) {
 638   DCHECK(network_task_runner_->BelongsToCurrentThread());
 639
 640   if (request_.get()) {
 641     request_->CancelWithError(error);
 642     ReleaseRequest();
 643   }
 644
 645   // Set the error manually.
 646   // Normally, calling URLRequest::CancelWithError() results in calling
 647   // OnReadCompleted() with bytes_read = -1 via an asynchronous task posted by
 648   // URLRequestJob::NotifyDone(). But, because the request was released
 649   // immediately after being canceled, the request could not call
 650   // OnReadCompleted() which overwrites |status_| with the error status.
 651   status_.set_status(URLRequestStatus::CANCELED);
 652   status_.set_error(error);
 653
 654   // Release the reference to the request context. There could be multiple
 655   // references to URLFetcher::Core at this point so it may take a while to
 656   // delete the object, but we cannot delay the destruction of the request
 657   // context.
 658   request_context_getter_ = NULL;
 659   first_party_for_cookies_ = GURL();
 660   url_request_data_key_ = NULL;
 661   url_request_create_data_callback_.Reset();
 662   was_cancelled_ = true;
 663 }
 664
 665 void URLFetcherCore::OnCompletedURLRequest(
 666     base::TimeDelta backoff_delay) {
 667   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 668
 669   // Save the status and backoff_delay so that delegates can read it.
 670   if (delegate_) {
 671     backoff_delay_ = backoff_delay;
 672     InformDelegateFetchIsComplete();
 673   }
 674 }
 675
 676 void URLFetcherCore::InformDelegateFetchIsComplete() {
 677   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 678   if (delegate_)
 679     delegate_->OnURLFetchComplete(fetcher_);
 680 }
 681
 682 void URLFetcherCore::NotifyMalformedContent() {
 683   DCHECK(network_task_runner_->BelongsToCurrentThread());
 684   if (url_throttler_entry_.get()) {
 685     int status_code = response_code_;
 686     if (status_code == URLFetcher::RESPONSE_CODE_INVALID) {
 687       // The status code will generally be known by the time clients
 688       // call the |ReceivedContentWasMalformed()| function (which ends up
 689       // calling the current function) but if it's not, we need to assume
 690       // the response was successful so that the total failure count
 691       // used to calculate exponential back-off goes up.
 692       status_code = 200;
 693     }
 694     url_throttler_entry_->ReceivedContentWasMalformed(status_code);
 695   }
 696 }
 697
 698 void URLFetcherCore::DidFinishWriting(int result) {
 699   if (result != OK) {
 700     CancelURLRequest(result);
 701     delegate_task_runner_->PostTask(
 702         FROM_HERE,
 703         base::Bind(&URLFetcherCore::InformDelegateFetchIsComplete, this));
 704     return;
 705   }
 706   // If the file was successfully closed, then the URL request is complete.
 707   RetryOrCompleteUrlFetch();
 708 }
 709
 710 void URLFetcherCore::RetryOrCompleteUrlFetch() {
 711   DCHECK(network_task_runner_->BelongsToCurrentThread());
 712   base::TimeDelta backoff_delay;
 713
 714   // Checks the response from server.
 715   if (response_code_ >= 500 ||
 716       status_.error() == ERR_TEMPORARILY_THROTTLED) {
 717     // When encountering a server error, we will send the request again
 718     // after backoff time.
 719     ++num_retries_on_5xx_;
 720
 721     // Note that backoff_delay may be 0 because (a) the
 722     // URLRequestThrottlerManager and related code does not
 723     // necessarily back off on the first error, (b) it only backs off
 724     // on some of the 5xx status codes, (c) not all URLRequestContexts
 725     // have a throttler manager.
 726     base::TimeTicks backoff_release_time = GetBackoffReleaseTime();
 727     backoff_delay = backoff_release_time - base::TimeTicks::Now();
 728     if (backoff_delay < base::TimeDelta())
 729       backoff_delay = base::TimeDelta();
 730
 731     if (automatically_retry_on_5xx_ &&
 732         num_retries_on_5xx_ <= max_retries_on_5xx_) {
 733       StartOnIOThread();
 734       return;
 735     }
 736   } else {
 737     backoff_delay = base::TimeDelta();
 738   }
 739
 740   // Retry if the request failed due to network changes.
 741   if (status_.error() == ERR_NETWORK_CHANGED &&
 742       num_retries_on_network_changes_ < max_retries_on_network_changes_) {
 743     ++num_retries_on_network_changes_;
 744
 745     // Retry soon, after flushing all the current tasks which may include
 746     // further network change observers.
 747     network_task_runner_->PostTask(
 748         FROM_HERE, base::Bind(&URLFetcherCore::StartOnIOThread, this));
 749     return;
 750   }
 751
 752   request_context_getter_ = NULL;
 753   first_party_for_cookies_ = GURL();
 754   url_request_data_key_ = NULL;
 755   url_request_create_data_callback_.Reset();
 756   bool posted = delegate_task_runner_->PostTask(
 757       FROM_HERE,
 758       base::Bind(&URLFetcherCore::OnCompletedURLRequest, this, backoff_delay));
 759
 760   // If the delegate message loop does not exist any more, then the delegate
 761   // should be gone too.
 762   DCHECK(posted || !delegate_);
 763 }
 764
 765 void URLFetcherCore::ReleaseRequest() {
 766   upload_progress_checker_timer_.reset();
 767   request_.reset();
 768   g_registry.Get().RemoveURLFetcherCore(this);
 769 }
 770
 771 base::TimeTicks URLFetcherCore::GetBackoffReleaseTime() {
 772   DCHECK(network_task_runner_->BelongsToCurrentThread());
 773
 774   if (!original_url_throttler_entry_.get())
 775     return base::TimeTicks();
 776
 777   base::TimeTicks original_url_backoff =
 778       original_url_throttler_entry_->GetExponentialBackoffReleaseTime();
 779   base::TimeTicks destination_url_backoff;
 780   if (url_throttler_entry_.get() &&
 781       original_url_throttler_entry_.get() != url_throttler_entry_.get()) {
 782     destination_url_backoff =
 783         url_throttler_entry_->GetExponentialBackoffReleaseTime();
 784   }
 785
 786   return original_url_backoff > destination_url_backoff ?
 787       original_url_backoff : destination_url_backoff;
 788 }
 789
 790 void URLFetcherCore::CompleteAddingUploadDataChunk(
 791     const std::string& content, bool is_last_chunk) {
 792   if (was_cancelled_) {
 793     // Since CompleteAddingUploadDataChunk() is posted as a *delayed* task, it
 794     // may run after the URLFetcher was already stopped.
 795     return;
 796   }
 797   DCHECK(is_chunked_upload_);
 798   DCHECK(request_.get());
 799   DCHECK(!content.empty());
 800   request_->AppendChunkToUpload(content.data(),
 801                                 static_cast<int>(content.length()),
 802                                 is_last_chunk);
 803 }
 804
 805 int URLFetcherCore::WriteBuffer(scoped_refptr<DrainableIOBuffer> data) {
 806   while (data->BytesRemaining() > 0) {
 807     const int result = response_writer_->Write(
 808         data.get(),
 809         data->BytesRemaining(),
 810         base::Bind(&URLFetcherCore::DidWriteBuffer, this, data));
 811     if (result < 0) {
 812       if (result != ERR_IO_PENDING)
 813         DidWriteBuffer(data, result);
 814       return result;
 815     }
 816     data->DidConsume(result);
 817   }
 818   return OK;
 819 }
 820
 821 void URLFetcherCore::DidWriteBuffer(scoped_refptr<DrainableIOBuffer> data,
 822                                     int result) {
 823   if (result < 0) {  // Handle errors.
 824     CancelURLRequest(result);
 825     response_writer_->Finish(base::Bind(&EmptyCompletionCallback));
 826     delegate_task_runner_->PostTask(
 827         FROM_HERE,
 828         base::Bind(&URLFetcherCore::InformDelegateFetchIsComplete, this));
 829     return;
 830   }
 831
 832   // Continue writing.
 833   data->DidConsume(result);
 834   if (WriteBuffer(data) < 0)
 835     return;
 836
 837   // Finished writing buffer_. Read some more, unless the request has been
 838   // cancelled and deleted.
 839   DCHECK_EQ(0, data->BytesRemaining());
 840   if (request_.get())
 841     ReadResponse();
 842 }
 843
 844 void URLFetcherCore::ReadResponse() {
 845   // Some servers may treat HEAD requests as GET requests. To free up the
 846   // network connection as soon as possible, signal that the request has
 847   // completed immediately, without trying to read any data back (all we care
 848   // about is the response code and headers, which we already have).
 849   int bytes_read = 0;
 850   if (request_->status().is_success() &&
 851       (request_type_ != URLFetcher::HEAD)) {
 852     if (!request_->Read(buffer_.get(), kBufferSize, &bytes_read))
 853       bytes_read = -1;  // Match OnReadCompleted() interface contract.
 854   }
 855   OnReadCompleted(request_.get(), bytes_read);
 856 }
 857
 858 void URLFetcherCore::InformDelegateUploadProgress() {
 859   DCHECK(network_task_runner_->BelongsToCurrentThread());
 860   if (request_.get()) {
 861     int64 current = request_->GetUploadProgress().position();
 862     if (current_upload_bytes_ != current) {
 863       current_upload_bytes_ = current;
 864       int64 total = -1;
 865       if (!is_chunked_upload_) {
 866         total = static_cast<int64>(request_->GetUploadProgress().size());
 867         // Total may be zero if the UploadDataStream::Init has not been called
 868         // yet. Don't send the upload progress until the size is initialized.
 869         if (!total)
 870           return;
 871       }
 872       delegate_task_runner_->PostTask(
 873           FROM_HERE,
 874           base::Bind(
 875               &URLFetcherCore::InformDelegateUploadProgressInDelegateThread,
 876               this, current, total));
 877     }
 878   }
 879 }
 880
 881 void URLFetcherCore::InformDelegateUploadProgressInDelegateThread(
 882     int64 current, int64 total) {
 883   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 884   if (delegate_)
 885     delegate_->OnURLFetchUploadProgress(fetcher_, current, total);
 886 }
 887
 888 void URLFetcherCore::InformDelegateDownloadProgress() {
 889   DCHECK(network_task_runner_->BelongsToCurrentThread());
 890   delegate_task_runner_->PostTask(
 891       FROM_HERE,
 892       base::Bind(
 893           &URLFetcherCore::InformDelegateDownloadProgressInDelegateThread,
 894           this, current_response_bytes_, total_response_bytes_));
 895 }
 896
 897 void URLFetcherCore::InformDelegateDownloadProgressInDelegateThread(
 898     int64 current, int64 total) {
 899   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 900   if (delegate_)
 901     delegate_->OnURLFetchDownloadProgress(fetcher_, current, total);
 902 }
 903
 904 }  // namespace net