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_macros.h"
  12 #include "base/profiler/scoped_tracker.h"
  13 #include "base/sequenced_task_runner.h"
  14 #include "base/single_thread_task_runner.h"
  15 #include "base/stl_util.h"
  16 #include "base/thread_task_runner_handle.h"
  17 #include "base/tracked_objects.h"
  18 #include "net/base/elements_upload_data_stream.h"
  19 #include "net/base/io_buffer.h"
  20 #include "net/base/load_flags.h"
  21 #include "net/base/net_errors.h"
  22 #include "net/base/request_priority.h"
  23 #include "net/base/upload_bytes_element_reader.h"
  24 #include "net/base/upload_data_stream.h"
  25 #include "net/base/upload_file_element_reader.h"
  26 #include "net/http/http_response_headers.h"
  27 #include "net/url_request/redirect_info.h"
  28 #include "net/url_request/url_fetcher_delegate.h"
  29 #include "net/url_request/url_fetcher_response_writer.h"
  30 #include "net/url_request/url_request_context.h"
  31 #include "net/url_request/url_request_context_getter.h"
  32 #include "net/url_request/url_request_throttler_manager.h"
  33
  34 namespace {
  35
  36 const int kBufferSize = 4096;
  37 const int kUploadProgressTimerInterval = 100;
  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   AssertHasNoUploadData();
 141   DCHECK(!is_chunked_upload_);
 142   DCHECK(upload_content_type_.empty());
 143
 144   // Empty |upload_content_type| is allowed iff the |upload_content| is empty.
 145   DCHECK(upload_content.empty() || !upload_content_type.empty());
 146
 147   upload_content_type_ = upload_content_type;
 148   upload_content_ = upload_content;
 149   upload_content_set_ = true;
 150 }
 151
 152 void URLFetcherCore::SetUploadFilePath(
 153     const std::string& upload_content_type,
 154     const base::FilePath& file_path,
 155     uint64 range_offset,
 156     uint64 range_length,
 157     scoped_refptr<base::TaskRunner> file_task_runner) {
 158   AssertHasNoUploadData();
 159   DCHECK(!is_chunked_upload_);
 160   DCHECK_EQ(upload_range_offset_, 0ULL);
 161   DCHECK_EQ(upload_range_length_, 0ULL);
 162   DCHECK(upload_content_type_.empty());
 163   DCHECK(!upload_content_type.empty());
 164
 165   upload_content_type_ = upload_content_type;
 166   upload_file_path_ = file_path;
 167   upload_range_offset_ = range_offset;
 168   upload_range_length_ = range_length;
 169   upload_file_task_runner_ = file_task_runner;
 170   upload_content_set_ = true;
 171 }
 172
 173 void URLFetcherCore::SetUploadStreamFactory(
 174     const std::string& upload_content_type,
 175     const URLFetcher::CreateUploadStreamCallback& factory) {
 176   AssertHasNoUploadData();
 177   DCHECK(!is_chunked_upload_);
 178   DCHECK(upload_content_type_.empty());
 179
 180   upload_content_type_ = upload_content_type;
 181   upload_stream_factory_ = factory;
 182   upload_content_set_ = true;
 183 }
 184
 185 void URLFetcherCore::SetChunkedUpload(const std::string& content_type) {
 186   if (!is_chunked_upload_) {
 187     AssertHasNoUploadData();
 188     DCHECK(upload_content_type_.empty());
 189   }
 190
 191   // Empty |content_type| is not allowed here, because it is impossible
 192   // to ensure non-empty upload content as it is not yet supplied.
 193   DCHECK(!content_type.empty());
 194
 195   upload_content_type_ = content_type;
 196   upload_content_.clear();
 197   is_chunked_upload_ = true;
 198 }
 199
 200 void URLFetcherCore::AppendChunkToUpload(const std::string& content,
 201                                          bool is_last_chunk) {
 202   DCHECK(delegate_task_runner_.get());
 203   DCHECK(network_task_runner_.get());
 204   network_task_runner_->PostTask(
 205       FROM_HERE,
 206       base::Bind(&URLFetcherCore::CompleteAddingUploadDataChunk, this, content,
 207                  is_last_chunk));
 208 }
 209
 210 void URLFetcherCore::SetLoadFlags(int load_flags) {
 211   load_flags_ = load_flags;
 212 }
 213
 214 int URLFetcherCore::GetLoadFlags() const {
 215   return load_flags_;
 216 }
 217
 218 void URLFetcherCore::SetReferrer(const std::string& referrer) {
 219   referrer_ = referrer;
 220 }
 221
 222 void URLFetcherCore::SetReferrerPolicy(
 223     URLRequest::ReferrerPolicy referrer_policy) {
 224   referrer_policy_ = referrer_policy;
 225 }
 226
 227 void URLFetcherCore::SetExtraRequestHeaders(
 228     const std::string& extra_request_headers) {
 229   extra_request_headers_.Clear();
 230   extra_request_headers_.AddHeadersFromString(extra_request_headers);
 231 }
 232
 233 void URLFetcherCore::AddExtraRequestHeader(const std::string& header_line) {
 234   extra_request_headers_.AddHeaderFromString(header_line);
 235 }
 236
 237 void URLFetcherCore::SetRequestContext(
 238     URLRequestContextGetter* request_context_getter) {
 239   DCHECK(!request_context_getter_.get());
 240   DCHECK(request_context_getter);
 241   request_context_getter_ = request_context_getter;
 242 }
 243
 244 void URLFetcherCore::SetFirstPartyForCookies(
 245     const GURL& first_party_for_cookies) {
 246   DCHECK(first_party_for_cookies_.is_empty());
 247   first_party_for_cookies_ = first_party_for_cookies;
 248 }
 249
 250 void URLFetcherCore::SetURLRequestUserData(
 251     const void* key,
 252     const URLFetcher::CreateDataCallback& create_data_callback) {
 253   DCHECK(key);
 254   DCHECK(!create_data_callback.is_null());
 255   url_request_data_key_ = key;
 256   url_request_create_data_callback_ = create_data_callback;
 257 }
 258
 259 void URLFetcherCore::SetStopOnRedirect(bool stop_on_redirect) {
 260   stop_on_redirect_ = stop_on_redirect;
 261 }
 262
 263 void URLFetcherCore::SetAutomaticallyRetryOn5xx(bool retry) {
 264   automatically_retry_on_5xx_ = retry;
 265 }
 266
 267 void URLFetcherCore::SetMaxRetriesOn5xx(int max_retries) {
 268   max_retries_on_5xx_ = max_retries;
 269 }
 270
 271 int URLFetcherCore::GetMaxRetriesOn5xx() const {
 272   return max_retries_on_5xx_;
 273 }
 274
 275 base::TimeDelta URLFetcherCore::GetBackoffDelay() const {
 276   return backoff_delay_;
 277 }
 278
 279 void URLFetcherCore::SetAutomaticallyRetryOnNetworkChanges(int max_retries) {
 280   max_retries_on_network_changes_ = max_retries;
 281 }
 282
 283 void URLFetcherCore::SaveResponseToFileAtPath(
 284     const base::FilePath& file_path,
 285     scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
 286   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 287   SaveResponseWithWriter(scoped_ptr<URLFetcherResponseWriter>(
 288       new URLFetcherFileWriter(file_task_runner, file_path)));
 289 }
 290
 291 void URLFetcherCore::SaveResponseToTemporaryFile(
 292     scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
 293   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 294   SaveResponseWithWriter(scoped_ptr<URLFetcherResponseWriter>(
 295       new URLFetcherFileWriter(file_task_runner, base::FilePath())));
 296 }
 297
 298 void URLFetcherCore::SaveResponseWithWriter(
 299     scoped_ptr<URLFetcherResponseWriter> response_writer) {
 300   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 301   response_writer_ = response_writer.Pass();
 302 }
 303
 304 HttpResponseHeaders* URLFetcherCore::GetResponseHeaders() const {
 305   return response_headers_.get();
 306 }
 307
 308 // TODO(panayiotis): socket_address_ is written in the IO thread,
 309 // if this is accessed in the UI thread, this could result in a race.
 310 // Same for response_headers_ above and was_fetched_via_proxy_ below.
 311 HostPortPair URLFetcherCore::GetSocketAddress() const {
 312   return socket_address_;
 313 }
 314
 315 bool URLFetcherCore::WasFetchedViaProxy() const {
 316   return was_fetched_via_proxy_;
 317 }
 318
 319 const GURL& URLFetcherCore::GetOriginalURL() const {
 320   return original_url_;
 321 }
 322
 323 const GURL& URLFetcherCore::GetURL() const {
 324   return url_;
 325 }
 326
 327 const URLRequestStatus& URLFetcherCore::GetStatus() const {
 328   return status_;
 329 }
 330
 331 int URLFetcherCore::GetResponseCode() const {
 332   return response_code_;
 333 }
 334
 335 const ResponseCookies& URLFetcherCore::GetCookies() const {
 336   return cookies_;
 337 }
 338
 339 void URLFetcherCore::ReceivedContentWasMalformed() {
 340   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 341   if (network_task_runner_.get()) {
 342     network_task_runner_->PostTask(
 343         FROM_HERE, base::Bind(&URLFetcherCore::NotifyMalformedContent, this));
 344   }
 345 }
 346
 347 bool URLFetcherCore::GetResponseAsString(
 348     std::string* out_response_string) const {
 349   URLFetcherStringWriter* string_writer =
 350       response_writer_ ? response_writer_->AsStringWriter() : NULL;
 351   if (!string_writer)
 352     return false;
 353
 354   *out_response_string = string_writer->data();
 355   UMA_HISTOGRAM_MEMORY_KB("UrlFetcher.StringResponseSize",
 356                           (string_writer->data().length() / 1024));
 357   return true;
 358 }
 359
 360 bool URLFetcherCore::GetResponseAsFilePath(bool take_ownership,
 361                                            base::FilePath* out_response_path) {
 362   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 363
 364   URLFetcherFileWriter* file_writer =
 365       response_writer_ ? response_writer_->AsFileWriter() : NULL;
 366   if (!file_writer)
 367     return false;
 368
 369   *out_response_path = file_writer->file_path();
 370
 371   if (take_ownership) {
 372     // Intentionally calling a file_writer_ method directly without posting
 373     // the task to network_task_runner_.
 374     //
 375     // This is for correctly handling the case when file_writer_->DisownFile()
 376     // is soon followed by URLFetcherCore::Stop(). We have to make sure that
 377     // DisownFile takes effect before Stop deletes file_writer_.
 378     //
 379     // This direct call should be thread-safe, since DisownFile itself does no
 380     // file operation. It just flips the state to be referred in destruction.
 381     file_writer->DisownFile();
 382   }
 383   return true;
 384 }
 385
 386 void URLFetcherCore::OnReceivedRedirect(URLRequest* request,
 387                                         const RedirectInfo& redirect_info,
 388                                         bool* defer_redirect) {
 389   DCHECK_EQ(request, request_.get());
 390   DCHECK(network_task_runner_->BelongsToCurrentThread());
 391   if (stop_on_redirect_) {
 392     stopped_on_redirect_ = true;
 393     url_ = redirect_info.new_url;
 394     response_code_ = request_->GetResponseCode();
 395     was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
 396     request->Cancel();
 397     OnReadCompleted(request, 0);
 398   }
 399 }
 400
 401 void URLFetcherCore::OnResponseStarted(URLRequest* request) {
 402   DCHECK_EQ(request, request_.get());
 403   DCHECK(network_task_runner_->BelongsToCurrentThread());
 404   if (request_->status().is_success()) {
 405     response_code_ = request_->GetResponseCode();
 406     response_headers_ = request_->response_headers();
 407     socket_address_ = request_->GetSocketAddress();
 408     was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
 409     total_response_bytes_ = request_->GetExpectedContentSize();
 410   }
 411
 412   ReadResponse();
 413 }
 414
 415 void URLFetcherCore::OnCertificateRequested(
 416     URLRequest* request,
 417     SSLCertRequestInfo* cert_request_info) {
 418   DCHECK_EQ(request, request_.get());
 419   DCHECK(network_task_runner_->BelongsToCurrentThread());
 420
 421   if (g_ignore_certificate_requests) {
 422     request->ContinueWithCertificate(NULL);
 423   } else {
 424     request->Cancel();
 425   }
 426 }
 427
 428 void URLFetcherCore::OnReadCompleted(URLRequest* request,
 429                                      int bytes_read) {
 430   DCHECK(request == request_);
 431   DCHECK(network_task_runner_->BelongsToCurrentThread());
 432
 433   if (!stopped_on_redirect_)
 434     url_ = request->url();
 435   URLRequestThrottlerManager* throttler_manager =
 436       request->context()->throttler_manager();
 437   if (throttler_manager)
 438     url_throttler_entry_ = throttler_manager->RegisterRequestUrl(url_);
 439
 440   do {
 441     if (!request_->status().is_success() || bytes_read <= 0)
 442       break;
 443
 444     current_response_bytes_ += bytes_read;
 445     InformDelegateDownloadProgress();
 446
 447     const int result =
 448         WriteBuffer(new DrainableIOBuffer(buffer_.get(), bytes_read));
 449     if (result < 0) {
 450       // Write failed or waiting for write completion.
 451       return;
 452     }
 453   } while (request_->Read(buffer_.get(), kBufferSize, &bytes_read));
 454
 455   const URLRequestStatus status = request_->status();
 456   if (status.is_success())
 457     request_->GetResponseCookies(&cookies_);
 458
 459   // See comments re: HEAD requests in ReadResponse().
 460   if (!status.is_io_pending() || request_type_ == URLFetcher::HEAD) {
 461     status_ = status;
 462     ReleaseRequest();
 463
 464     // No more data to write.
 465     const int result = response_writer_->Finish(
 466         base::Bind(&URLFetcherCore::DidFinishWriting, this));
 467     if (result != ERR_IO_PENDING)
 468       DidFinishWriting(result);
 469   }
 470 }
 471
 472 void URLFetcherCore::OnContextShuttingDown() {
 473   DCHECK(request_);
 474   CancelRequestAndInformDelegate(ERR_CONTEXT_SHUT_DOWN);
 475 }
 476
 477 void URLFetcherCore::CancelAll() {
 478   g_registry.Get().CancelAll();
 479 }
 480
 481 int URLFetcherCore::GetNumFetcherCores() {
 482   return g_registry.Get().size();
 483 }
 484
 485 void URLFetcherCore::SetIgnoreCertificateRequests(bool ignored) {
 486   g_ignore_certificate_requests = ignored;
 487 }
 488
 489 URLFetcherCore::~URLFetcherCore() {
 490   // |request_| should be NULL. If not, it's unsafe to delete it here since we
 491   // may not be on the IO thread.
 492   DCHECK(!request_.get());
 493 }
 494
 495 void URLFetcherCore::StartOnIOThread() {
 496   DCHECK(network_task_runner_->BelongsToCurrentThread());
 497
 498   if (!response_writer_)
 499     response_writer_.reset(new URLFetcherStringWriter);
 500
 501   const int result = response_writer_->Initialize(
 502       base::Bind(&URLFetcherCore::DidInitializeWriter, this));
 503   if (result != ERR_IO_PENDING)
 504     DidInitializeWriter(result);
 505 }
 506
 507 void URLFetcherCore::StartURLRequest() {
 508   DCHECK(network_task_runner_->BelongsToCurrentThread());
 509
 510   if (was_cancelled_) {
 511     // Since StartURLRequest() is posted as a *delayed* task, it may
 512     // run after the URLFetcher was already stopped.
 513     return;
 514   }
 515
 516   if (!request_context_getter_->GetURLRequestContext()) {
 517     CancelRequestAndInformDelegate(ERR_CONTEXT_SHUT_DOWN);
 518     return;
 519   }
 520
 521   DCHECK(request_context_getter_.get());
 522   DCHECK(!request_.get());
 523
 524   g_registry.Get().AddURLFetcherCore(this);
 525   current_response_bytes_ = 0;
 526   request_context_getter_->AddObserver(this);
 527   request_ = request_context_getter_->GetURLRequestContext()->CreateRequest(
 528       original_url_, DEFAULT_PRIORITY, this);
 529   request_->set_stack_trace(stack_trace_);
 530   int flags = request_->load_flags() | load_flags_;
 531
 532   if (is_chunked_upload_)
 533     request_->EnableChunkedUpload();
 534   request_->SetLoadFlags(flags);
 535   request_->SetReferrer(referrer_);
 536   request_->set_referrer_policy(referrer_policy_);
 537   request_->set_first_party_for_cookies(first_party_for_cookies_.is_empty() ?
 538       original_url_ : first_party_for_cookies_);
 539   if (url_request_data_key_ && !url_request_create_data_callback_.is_null()) {
 540     request_->SetUserData(url_request_data_key_,
 541                           url_request_create_data_callback_.Run());
 542   }
 543
 544   switch (request_type_) {
 545     case URLFetcher::GET:
 546       break;
 547
 548     case URLFetcher::POST:
 549     case URLFetcher::PUT:
 550     case URLFetcher::PATCH: {
 551       // Upload content must be set.
 552       DCHECK(is_chunked_upload_ || upload_content_set_);
 553
 554       request_->set_method(
 555           request_type_ == URLFetcher::POST ? "POST" :
 556           request_type_ == URLFetcher::PUT ? "PUT" : "PATCH");
 557       if (!upload_content_type_.empty()) {
 558         extra_request_headers_.SetHeader(HttpRequestHeaders::kContentType,
 559                                          upload_content_type_);
 560       }
 561       if (!upload_content_.empty()) {
 562         scoped_ptr<UploadElementReader> reader(new UploadBytesElementReader(
 563             upload_content_.data(), upload_content_.size()));
 564         request_->set_upload(
 565             ElementsUploadDataStream::CreateWithReader(reader.Pass(), 0));
 566       } else if (!upload_file_path_.empty()) {
 567         scoped_ptr<UploadElementReader> reader(
 568             new UploadFileElementReader(upload_file_task_runner_.get(),
 569                                         upload_file_path_,
 570                                         upload_range_offset_,
 571                                         upload_range_length_,
 572                                         base::Time()));
 573         request_->set_upload(
 574             ElementsUploadDataStream::CreateWithReader(reader.Pass(), 0));
 575       } else if (!upload_stream_factory_.is_null()) {
 576         scoped_ptr<UploadDataStream> stream = upload_stream_factory_.Run();
 577         DCHECK(stream);
 578         request_->set_upload(stream.Pass());
 579       }
 580
 581       current_upload_bytes_ = -1;
 582       // TODO(kinaba): http://crbug.com/118103. Implement upload callback in the
 583       //  layer and avoid using timer here.
 584       upload_progress_checker_timer_.reset(
 585           new base::RepeatingTimer<URLFetcherCore>());
 586       upload_progress_checker_timer_->Start(
 587           FROM_HERE,
 588           base::TimeDelta::FromMilliseconds(kUploadProgressTimerInterval),
 589           this,
 590           &URLFetcherCore::InformDelegateUploadProgress);
 591       break;
 592     }
 593
 594     case URLFetcher::HEAD:
 595       request_->set_method("HEAD");
 596       break;
 597
 598     case URLFetcher::DELETE_REQUEST:
 599       request_->set_method("DELETE");
 600       break;
 601
 602     default:
 603       NOTREACHED();
 604   }
 605
 606   if (!extra_request_headers_.IsEmpty())
 607     request_->SetExtraRequestHeaders(extra_request_headers_);
 608
 609   request_->Start();
 610 }
 611
 612 void URLFetcherCore::DidInitializeWriter(int result) {
 613   if (result != OK) {
 614     CancelRequestAndInformDelegate(result);
 615     return;
 616   }
 617   StartURLRequestWhenAppropriate();
 618 }
 619
 620 void URLFetcherCore::StartURLRequestWhenAppropriate() {
 621   DCHECK(network_task_runner_->BelongsToCurrentThread());
 622
 623   if (was_cancelled_)
 624     return;
 625
 626   DCHECK(request_context_getter_.get());
 627
 628   // Check if the request should be delayed, and if so, post a task to start it
 629   // after the delay has expired.  Otherwise, start it now.
 630
 631   URLRequestContext* context = request_context_getter_->GetURLRequestContext();
 632   // If the context has been shut down, or there's no ThrottlerManager, just
 633   // start the request.  In the former case, StartURLRequest() will just inform
 634   // the URLFetcher::Delegate the request has been canceled.
 635   if (context && context->throttler_manager()) {
 636     if (!original_url_throttler_entry_.get()) {
 637       original_url_throttler_entry_ =
 638           context->throttler_manager()->RegisterRequestUrl(original_url_);
 639     }
 640
 641     if (original_url_throttler_entry_.get()) {
 642       int64 delay =
 643           original_url_throttler_entry_->ReserveSendingTimeForNextRequest(
 644               GetBackoffReleaseTime());
 645       if (delay != 0) {
 646         base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
 647             FROM_HERE, base::Bind(&URLFetcherCore::StartURLRequest, this),
 648             base::TimeDelta::FromMilliseconds(delay));
 649         return;
 650       }
 651     }
 652   }
 653
 654   StartURLRequest();
 655 }
 656
 657 void URLFetcherCore::CancelURLRequest(int error) {
 658   DCHECK(network_task_runner_->BelongsToCurrentThread());
 659
 660   if (request_.get()) {
 661     request_->CancelWithError(error);
 662     ReleaseRequest();
 663   }
 664
 665   // Set the error manually.
 666   // Normally, calling URLRequest::CancelWithError() results in calling
 667   // OnReadCompleted() with bytes_read = -1 via an asynchronous task posted by
 668   // URLRequestJob::NotifyDone(). But, because the request was released
 669   // immediately after being canceled, the request could not call
 670   // OnReadCompleted() which overwrites |status_| with the error status.
 671   status_ = URLRequestStatus(URLRequestStatus::CANCELED, error);
 672
 673   // Release the reference to the request context. There could be multiple
 674   // references to URLFetcher::Core at this point so it may take a while to
 675   // delete the object, but we cannot delay the destruction of the request
 676   // context.
 677   request_context_getter_ = NULL;
 678   first_party_for_cookies_ = GURL();
 679   url_request_data_key_ = NULL;
 680   url_request_create_data_callback_.Reset();
 681   was_cancelled_ = true;
 682 }
 683
 684 void URLFetcherCore::OnCompletedURLRequest(
 685     base::TimeDelta backoff_delay) {
 686   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 687
 688   // Save the status and backoff_delay so that delegates can read it.
 689   if (delegate_) {
 690     backoff_delay_ = backoff_delay;
 691     InformDelegateFetchIsComplete();
 692   }
 693 }
 694
 695 void URLFetcherCore::InformDelegateFetchIsComplete() {
 696   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 697   if (delegate_)
 698     delegate_->OnURLFetchComplete(fetcher_);
 699 }
 700
 701 void URLFetcherCore::NotifyMalformedContent() {
 702   DCHECK(network_task_runner_->BelongsToCurrentThread());
 703   if (url_throttler_entry_.get()) {
 704     int status_code = response_code_;
 705     if (status_code == URLFetcher::RESPONSE_CODE_INVALID) {
 706       // The status code will generally be known by the time clients
 707       // call the |ReceivedContentWasMalformed()| function (which ends up
 708       // calling the current function) but if it's not, we need to assume
 709       // the response was successful so that the total failure count
 710       // used to calculate exponential back-off goes up.
 711       status_code = 200;
 712     }
 713     url_throttler_entry_->ReceivedContentWasMalformed(status_code);
 714   }
 715 }
 716
 717 void URLFetcherCore::DidFinishWriting(int result) {
 718   if (result != OK) {
 719     CancelRequestAndInformDelegate(result);
 720     return;
 721   }
 722   // If the file was successfully closed, then the URL request is complete.
 723   RetryOrCompleteUrlFetch();
 724 }
 725
 726 void URLFetcherCore::RetryOrCompleteUrlFetch() {
 727   DCHECK(network_task_runner_->BelongsToCurrentThread());
 728   base::TimeDelta backoff_delay;
 729
 730   // Checks the response from server.
 731   if (response_code_ >= 500 ||
 732       status_.error() == ERR_TEMPORARILY_THROTTLED) {
 733     // When encountering a server error, we will send the request again
 734     // after backoff time.
 735     ++num_retries_on_5xx_;
 736
 737     // Note that backoff_delay may be 0 because (a) the
 738     // URLRequestThrottlerManager and related code does not
 739     // necessarily back off on the first error, (b) it only backs off
 740     // on some of the 5xx status codes, (c) not all URLRequestContexts
 741     // have a throttler manager.
 742     base::TimeTicks backoff_release_time = GetBackoffReleaseTime();
 743     backoff_delay = backoff_release_time - base::TimeTicks::Now();
 744     if (backoff_delay < base::TimeDelta())
 745       backoff_delay = base::TimeDelta();
 746
 747     if (automatically_retry_on_5xx_ &&
 748         num_retries_on_5xx_ <= max_retries_on_5xx_) {
 749       StartOnIOThread();
 750       return;
 751     }
 752   } else {
 753     backoff_delay = base::TimeDelta();
 754   }
 755
 756   // Retry if the request failed due to network changes.
 757   if (status_.error() == ERR_NETWORK_CHANGED &&
 758       num_retries_on_network_changes_ < max_retries_on_network_changes_) {
 759     ++num_retries_on_network_changes_;
 760
 761     // Retry soon, after flushing all the current tasks which may include
 762     // further network change observers.
 763     network_task_runner_->PostTask(
 764         FROM_HERE, base::Bind(&URLFetcherCore::StartOnIOThread, this));
 765     return;
 766   }
 767
 768   request_context_getter_ = NULL;
 769   first_party_for_cookies_ = GURL();
 770   url_request_data_key_ = NULL;
 771   url_request_create_data_callback_.Reset();
 772   bool posted = delegate_task_runner_->PostTask(
 773       FROM_HERE,
 774       base::Bind(&URLFetcherCore::OnCompletedURLRequest, this, backoff_delay));
 775
 776   // If the delegate message loop does not exist any more, then the delegate
 777   // should be gone too.
 778   DCHECK(posted || !delegate_);
 779 }
 780
 781 void URLFetcherCore::CancelRequestAndInformDelegate(int result) {
 782   CancelURLRequest(result);
 783   delegate_task_runner_->PostTask(
 784       FROM_HERE,
 785       base::Bind(&URLFetcherCore::InformDelegateFetchIsComplete, this));
 786 }
 787
 788 void URLFetcherCore::ReleaseRequest() {
 789   request_context_getter_->RemoveObserver(this);
 790   upload_progress_checker_timer_.reset();
 791   request_.reset();
 792   g_registry.Get().RemoveURLFetcherCore(this);
 793 }
 794
 795 base::TimeTicks URLFetcherCore::GetBackoffReleaseTime() {
 796   DCHECK(network_task_runner_->BelongsToCurrentThread());
 797
 798   if (!original_url_throttler_entry_.get())
 799     return base::TimeTicks();
 800
 801   base::TimeTicks original_url_backoff =
 802       original_url_throttler_entry_->GetExponentialBackoffReleaseTime();
 803   base::TimeTicks destination_url_backoff;
 804   if (url_throttler_entry_.get() &&
 805       original_url_throttler_entry_.get() != url_throttler_entry_.get()) {
 806     destination_url_backoff =
 807         url_throttler_entry_->GetExponentialBackoffReleaseTime();
 808   }
 809
 810   return original_url_backoff > destination_url_backoff ?
 811       original_url_backoff : destination_url_backoff;
 812 }
 813
 814 void URLFetcherCore::CompleteAddingUploadDataChunk(
 815     const std::string& content, bool is_last_chunk) {
 816   if (was_cancelled_) {
 817     // Since CompleteAddingUploadDataChunk() is posted as a *delayed* task, it
 818     // may run after the URLFetcher was already stopped.
 819     return;
 820   }
 821   DCHECK(is_chunked_upload_);
 822   DCHECK(request_.get());
 823   DCHECK(!content.empty());
 824   request_->AppendChunkToUpload(content.data(),
 825                                 static_cast<int>(content.length()),
 826                                 is_last_chunk);
 827 }
 828
 829 int URLFetcherCore::WriteBuffer(scoped_refptr<DrainableIOBuffer> data) {
 830   while (data->BytesRemaining() > 0) {
 831     const int result = response_writer_->Write(
 832         data.get(),
 833         data->BytesRemaining(),
 834         base::Bind(&URLFetcherCore::DidWriteBuffer, this, data));
 835     if (result < 0) {
 836       if (result != ERR_IO_PENDING)
 837         DidWriteBuffer(data, result);
 838       return result;
 839     }
 840     data->DidConsume(result);
 841   }
 842   return OK;
 843 }
 844
 845 void URLFetcherCore::DidWriteBuffer(scoped_refptr<DrainableIOBuffer> data,
 846                                     int result) {
 847   if (result < 0) {  // Handle errors.
 848     response_writer_->Finish(base::Bind(&EmptyCompletionCallback));
 849     CancelRequestAndInformDelegate(result);
 850     return;
 851   }
 852
 853   // Continue writing.
 854   data->DidConsume(result);
 855   if (WriteBuffer(data) < 0)
 856     return;
 857
 858   // Finished writing buffer_. Read some more, unless the request has been
 859   // cancelled and deleted.
 860   DCHECK_EQ(0, data->BytesRemaining());
 861   if (request_.get())
 862     ReadResponse();
 863 }
 864
 865 void URLFetcherCore::ReadResponse() {
 866   // Some servers may treat HEAD requests as GET requests. To free up the
 867   // network connection as soon as possible, signal that the request has
 868   // completed immediately, without trying to read any data back (all we care
 869   // about is the response code and headers, which we already have).
 870   int bytes_read = 0;
 871   if (request_->status().is_success() &&
 872       (request_type_ != URLFetcher::HEAD)) {
 873     if (!request_->Read(buffer_.get(), kBufferSize, &bytes_read))
 874       bytes_read = -1;  // Match OnReadCompleted() interface contract.
 875   }
 876   OnReadCompleted(request_.get(), bytes_read);
 877 }
 878
 879 void URLFetcherCore::InformDelegateUploadProgress() {
 880   DCHECK(network_task_runner_->BelongsToCurrentThread());
 881   if (request_.get()) {
 882     int64 current = request_->GetUploadProgress().position();
 883     if (current_upload_bytes_ != current) {
 884       current_upload_bytes_ = current;
 885       int64 total = -1;
 886       if (!is_chunked_upload_) {
 887         total = static_cast<int64>(request_->GetUploadProgress().size());
 888         // Total may be zero if the UploadDataStream::Init has not been called
 889         // yet. Don't send the upload progress until the size is initialized.
 890         if (!total)
 891           return;
 892       }
 893       delegate_task_runner_->PostTask(
 894           FROM_HERE,
 895           base::Bind(
 896               &URLFetcherCore::InformDelegateUploadProgressInDelegateThread,
 897               this, current, total));
 898     }
 899   }
 900 }
 901
 902 void URLFetcherCore::InformDelegateUploadProgressInDelegateThread(
 903     int64 current, int64 total) {
 904   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 905   if (delegate_)
 906     delegate_->OnURLFetchUploadProgress(fetcher_, current, total);
 907 }
 908
 909 void URLFetcherCore::InformDelegateDownloadProgress() {
 910   DCHECK(network_task_runner_->BelongsToCurrentThread());
 911
 912   // TODO(pkasting): Remove ScopedTracker below once crbug.com/455952 is fixed.
 913   tracked_objects::ScopedTracker tracking_profile2(
 914       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 915           "455952 delegate_task_runner_->PostTask()"));
 916
 917   delegate_task_runner_->PostTask(
 918       FROM_HERE,
 919       base::Bind(
 920           &URLFetcherCore::InformDelegateDownloadProgressInDelegateThread,
 921           this, current_response_bytes_, total_response_bytes_));
 922 }
 923
 924 void URLFetcherCore::InformDelegateDownloadProgressInDelegateThread(
 925     int64 current, int64 total) {
 926   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
 927   if (delegate_)
 928     delegate_->OnURLFetchDownloadProgress(fetcher_, current, total);
 929 }
 930
 931 void URLFetcherCore::AssertHasNoUploadData() const {
 932   DCHECK(!upload_content_set_);
 933   DCHECK(upload_content_.empty());
 934   DCHECK(upload_file_path_.empty());
 935   DCHECK(upload_stream_factory_.is_null());
 936 }
 937
 938 }  // namespace net