net/url_request/url_fetcher

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This source file includes following definitions.
EmptyCompletionCallback
AddURLFetcherCore
RemoveURLFetcherCore
CancelAll
total_response_bytes_
Start
Stop
SetUploadData
SetUploadFilePath
SetChunkedUpload
AppendChunkToUpload
SetLoadFlags
GetLoadFlags
SetReferrer
SetReferrerPolicy
SetExtraRequestHeaders
AddExtraRequestHeader
SetRequestContext
SetFirstPartyForCookies
SetURLRequestUserData
SetStopOnRedirect
SetAutomaticallyRetryOn5xx
SetMaxRetriesOn5xx
GetMaxRetriesOn5xx
GetBackoffDelay
SetAutomaticallyRetryOnNetworkChanges
SaveResponseToFileAtPath
SaveResponseToTemporaryFile
SaveResponseWithWriter
GetResponseHeaders
GetSocketAddress
WasFetchedViaProxy
GetOriginalURL
GetURL
GetStatus
GetResponseCode
GetCookies
ReceivedContentWasMalformed
GetResponseAsString
GetResponseAsFilePath
OnReceivedRedirect
OnResponseStarted
OnCertificateRequested
OnReadCompleted
CancelAll
GetNumFetcherCores
SetEnableInterceptionForTests
SetIgnoreCertificateRequests
StartOnIOThread
StartURLRequest
DidInitializeWriter
StartURLRequestWhenAppropriate
CancelURLRequest
OnCompletedURLRequest
InformDelegateFetchIsComplete
NotifyMalformedContent
DidFinishWriting
RetryOrCompleteUrlFetch
ReleaseRequest
GetBackoffReleaseTime
CompleteAddingUploadDataChunk
WriteBuffer
DidWriteBuffer
ReadResponse
InformDelegateUploadProgress
InformDelegateUploadProgressInDelegateThread
InformDelegateDownloadProgress
InformDelegateDownloadProgressInDelegateThread
// Copyright (c) 2012 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 "net/url_request/url_fetcher_core.h"

#include "base/bind.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/sequenced_task_runner.h"
#include "base/single_thread_task_runner.h"
#include "base/stl_util.h"
#include "base/thread_task_runner_handle.h"
#include "base/tracked_objects.h"
#include "net/base/io_buffer.h"
#include "net/base/load_flags.h"
#include "net/base/net_errors.h"
#include "net/base/request_priority.h"
#include "net/base/upload_bytes_element_reader.h"
#include "net/base/upload_data_stream.h"
#include "net/base/upload_file_element_reader.h"
#include "net/http/http_response_headers.h"
#include "net/url_request/url_fetcher_delegate.h"
#include "net/url_request/url_fetcher_response_writer.h"
#include "net/url_request/url_request_context.h"
#include "net/url_request/url_request_context_getter.h"
#include "net/url_request/url_request_throttler_manager.h"

namespace {

const int kBufferSize = 4096;
const int kUploadProgressTimerInterval = 100;
bool g_interception_enabled = false;
bool g_ignore_certificate_requests = false;

void EmptyCompletionCallback(int result) {}

}  // namespace

namespace net {

// URLFetcherCore::Registry ---------------------------------------------------

URLFetcherCore::Registry::Registry() {}
URLFetcherCore::Registry::~Registry() {}

void URLFetcherCore::Registry::AddURLFetcherCore(URLFetcherCore* core) {
  DCHECK(!ContainsKey(fetchers_, core));
  fetchers_.insert(core);
}

void URLFetcherCore::Registry::RemoveURLFetcherCore(URLFetcherCore* core) {
  DCHECK(ContainsKey(fetchers_, core));
  fetchers_.erase(core);
}

void URLFetcherCore::Registry::CancelAll() {
  while (!fetchers_.empty())
    (*fetchers_.begin())->CancelURLRequest(ERR_ABORTED);
}

// URLFetcherCore -------------------------------------------------------------

// static
base::LazyInstance<URLFetcherCore::Registry>
    URLFetcherCore::g_registry = LAZY_INSTANCE_INITIALIZER;

URLFetcherCore::URLFetcherCore(URLFetcher* fetcher,
                               const GURL& original_url,
                               URLFetcher::RequestType request_type,
                               URLFetcherDelegate* d)
    : fetcher_(fetcher),
      original_url_(original_url),
      request_type_(request_type),
      delegate_(d),
      delegate_task_runner_(base::ThreadTaskRunnerHandle::Get()),
      load_flags_(LOAD_NORMAL),
      response_code_(URLFetcher::RESPONSE_CODE_INVALID),
      buffer_(new IOBuffer(kBufferSize)),
      url_request_data_key_(NULL),
      was_fetched_via_proxy_(false),
      upload_content_set_(false),
      upload_range_offset_(0),
      upload_range_length_(0),
      referrer_policy_(
          URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE),
      is_chunked_upload_(false),
      was_cancelled_(false),
      stop_on_redirect_(false),
      stopped_on_redirect_(false),
      automatically_retry_on_5xx_(true),
      num_retries_on_5xx_(0),
      max_retries_on_5xx_(0),
      num_retries_on_network_changes_(0),
      max_retries_on_network_changes_(0),
      current_upload_bytes_(-1),
      current_response_bytes_(0),
      total_response_bytes_(-1) {
  CHECK(original_url_.is_valid());
}

void URLFetcherCore::Start() {
  DCHECK(delegate_task_runner_.get());
  DCHECK(request_context_getter_.get()) << "We need an URLRequestContext!";
  if (network_task_runner_.get()) {
    DCHECK_EQ(network_task_runner_,
              request_context_getter_->GetNetworkTaskRunner());
  } else {
    network_task_runner_ = request_context_getter_->GetNetworkTaskRunner();
  }
  DCHECK(network_task_runner_.get()) << "We need an IO task runner";

  network_task_runner_->PostTask(
      FROM_HERE, base::Bind(&URLFetcherCore::StartOnIOThread, this));
}

void URLFetcherCore::Stop() {
  if (delegate_task_runner_.get())  // May be NULL in tests.
    DCHECK(delegate_task_runner_->BelongsToCurrentThread());

  delegate_ = NULL;
  fetcher_ = NULL;
  if (!network_task_runner_.get())
    return;
  if (network_task_runner_->RunsTasksOnCurrentThread()) {
    CancelURLRequest(ERR_ABORTED);
  } else {
    network_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&URLFetcherCore::CancelURLRequest, this, ERR_ABORTED));
  }
}

void URLFetcherCore::SetUploadData(const std::string& upload_content_type,
                                   const std::string& upload_content) {
  DCHECK(!is_chunked_upload_);
  DCHECK(!upload_content_set_);
  DCHECK(upload_content_.empty());
  DCHECK(upload_file_path_.empty());
  DCHECK(upload_content_type_.empty());

  // Empty |upload_content_type| is allowed iff the |upload_content| is empty.
  DCHECK(upload_content.empty() || !upload_content_type.empty());

  upload_content_type_ = upload_content_type;
  upload_content_ = upload_content;
  upload_content_set_ = true;
}

void URLFetcherCore::SetUploadFilePath(
    const std::string& upload_content_type,
    const base::FilePath& file_path,
    uint64 range_offset,
    uint64 range_length,
    scoped_refptr<base::TaskRunner> file_task_runner) {
  DCHECK(!is_chunked_upload_);
  DCHECK(!upload_content_set_);
  DCHECK(upload_content_.empty());
  DCHECK(upload_file_path_.empty());
  DCHECK_EQ(upload_range_offset_, 0ULL);
  DCHECK_EQ(upload_range_length_, 0ULL);
  DCHECK(upload_content_type_.empty());
  DCHECK(!upload_content_type.empty());

  upload_content_type_ = upload_content_type;
  upload_file_path_ = file_path;
  upload_range_offset_ = range_offset;
  upload_range_length_ = range_length;
  upload_file_task_runner_ = file_task_runner;
  upload_content_set_ = true;
}

void URLFetcherCore::SetChunkedUpload(const std::string& content_type) {
  DCHECK(is_chunked_upload_ ||
         (upload_content_type_.empty() &&
          upload_content_.empty()));

  // Empty |content_type| is not allowed here, because it is impossible
  // to ensure non-empty upload content as it is not yet supplied.
  DCHECK(!content_type.empty());

  upload_content_type_ = content_type;
  upload_content_.clear();
  is_chunked_upload_ = true;
}

void URLFetcherCore::AppendChunkToUpload(const std::string& content,
                                         bool is_last_chunk) {
  DCHECK(delegate_task_runner_.get());
  DCHECK(network_task_runner_.get());
  network_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(&URLFetcherCore::CompleteAddingUploadDataChunk, this, content,
                 is_last_chunk));
}

void URLFetcherCore::SetLoadFlags(int load_flags) {
  load_flags_ = load_flags;
}

int URLFetcherCore::GetLoadFlags() const {
  return load_flags_;
}

void URLFetcherCore::SetReferrer(const std::string& referrer) {
  referrer_ = referrer;
}

void URLFetcherCore::SetReferrerPolicy(
    URLRequest::ReferrerPolicy referrer_policy) {
  referrer_policy_ = referrer_policy;
}

void URLFetcherCore::SetExtraRequestHeaders(
    const std::string& extra_request_headers) {
  extra_request_headers_.Clear();
  extra_request_headers_.AddHeadersFromString(extra_request_headers);
}

void URLFetcherCore::AddExtraRequestHeader(const std::string& header_line) {
  extra_request_headers_.AddHeaderFromString(header_line);
}

void URLFetcherCore::SetRequestContext(
    URLRequestContextGetter* request_context_getter) {
  DCHECK(!request_context_getter_.get());
  DCHECK(request_context_getter);
  request_context_getter_ = request_context_getter;
}

void URLFetcherCore::SetFirstPartyForCookies(
    const GURL& first_party_for_cookies) {
  DCHECK(first_party_for_cookies_.is_empty());
  first_party_for_cookies_ = first_party_for_cookies;
}

void URLFetcherCore::SetURLRequestUserData(
    const void* key,
    const URLFetcher::CreateDataCallback& create_data_callback) {
  DCHECK(key);
  DCHECK(!create_data_callback.is_null());
  url_request_data_key_ = key;
  url_request_create_data_callback_ = create_data_callback;
}

void URLFetcherCore::SetStopOnRedirect(bool stop_on_redirect) {
  stop_on_redirect_ = stop_on_redirect;
}

void URLFetcherCore::SetAutomaticallyRetryOn5xx(bool retry) {
  automatically_retry_on_5xx_ = retry;
}

void URLFetcherCore::SetMaxRetriesOn5xx(int max_retries) {
  max_retries_on_5xx_ = max_retries;
}

int URLFetcherCore::GetMaxRetriesOn5xx() const {
  return max_retries_on_5xx_;
}

base::TimeDelta URLFetcherCore::GetBackoffDelay() const {
  return backoff_delay_;
}

void URLFetcherCore::SetAutomaticallyRetryOnNetworkChanges(int max_retries) {
  max_retries_on_network_changes_ = max_retries;
}

void URLFetcherCore::SaveResponseToFileAtPath(
    const base::FilePath& file_path,
    scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());
  SaveResponseWithWriter(scoped_ptr<URLFetcherResponseWriter>(
      new URLFetcherFileWriter(file_task_runner, file_path)));
}

void URLFetcherCore::SaveResponseToTemporaryFile(
    scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());
  SaveResponseWithWriter(scoped_ptr<URLFetcherResponseWriter>(
      new URLFetcherFileWriter(file_task_runner, base::FilePath())));
}

void URLFetcherCore::SaveResponseWithWriter(
    scoped_ptr<URLFetcherResponseWriter> response_writer) {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());
  response_writer_ = response_writer.Pass();
}

HttpResponseHeaders* URLFetcherCore::GetResponseHeaders() const {
  return response_headers_.get();
}

// TODO(panayiotis): socket_address_ is written in the IO thread,
// if this is accessed in the UI thread, this could result in a race.
// Same for response_headers_ above and was_fetched_via_proxy_ below.
HostPortPair URLFetcherCore::GetSocketAddress() const {
  return socket_address_;
}

bool URLFetcherCore::WasFetchedViaProxy() const {
  return was_fetched_via_proxy_;
}

const GURL& URLFetcherCore::GetOriginalURL() const {
  return original_url_;
}

const GURL& URLFetcherCore::GetURL() const {
  return url_;
}

const URLRequestStatus& URLFetcherCore::GetStatus() const {
  return status_;
}

int URLFetcherCore::GetResponseCode() const {
  return response_code_;
}

const ResponseCookies& URLFetcherCore::GetCookies() const {
  return cookies_;
}

void URLFetcherCore::ReceivedContentWasMalformed() {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());
  if (network_task_runner_.get()) {
    network_task_runner_->PostTask(
        FROM_HERE, base::Bind(&URLFetcherCore::NotifyMalformedContent, this));
  }
}

bool URLFetcherCore::GetResponseAsString(
    std::string* out_response_string) const {
  URLFetcherStringWriter* string_writer =
      response_writer_ ? response_writer_->AsStringWriter() : NULL;
  if (!string_writer)
    return false;

  *out_response_string = string_writer->data();
  UMA_HISTOGRAM_MEMORY_KB("UrlFetcher.StringResponseSize",
                          (string_writer->data().length() / 1024));
  return true;
}

bool URLFetcherCore::GetResponseAsFilePath(bool take_ownership,
                                           base::FilePath* out_response_path) {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());

  URLFetcherFileWriter* file_writer =
      response_writer_ ? response_writer_->AsFileWriter() : NULL;
  if (!file_writer)
    return false;

  *out_response_path = file_writer->file_path();

  if (take_ownership) {
    // Intentionally calling a file_writer_ method directly without posting
    // the task to network_task_runner_.
    //
    // This is for correctly handling the case when file_writer_->DisownFile()
    // is soon followed by URLFetcherCore::Stop(). We have to make sure that
    // DisownFile takes effect before Stop deletes file_writer_.
    //
    // This direct call should be thread-safe, since DisownFile itself does no
    // file operation. It just flips the state to be referred in destruction.
    file_writer->DisownFile();
  }
  return true;
}

void URLFetcherCore::OnReceivedRedirect(URLRequest* request,
                                        const GURL& new_url,
                                        bool* defer_redirect) {
  DCHECK_EQ(request, request_.get());
  DCHECK(network_task_runner_->BelongsToCurrentThread());
  if (stop_on_redirect_) {
    stopped_on_redirect_ = true;
    url_ = new_url;
    response_code_ = request_->GetResponseCode();
    was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
    request->Cancel();
    OnReadCompleted(request, 0);
  }
}

void URLFetcherCore::OnResponseStarted(URLRequest* request) {
  DCHECK_EQ(request, request_.get());
  DCHECK(network_task_runner_->BelongsToCurrentThread());
  if (request_->status().is_success()) {
    response_code_ = request_->GetResponseCode();
    response_headers_ = request_->response_headers();
    socket_address_ = request_->GetSocketAddress();
    was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
    total_response_bytes_ = request_->GetExpectedContentSize();
  }

  ReadResponse();
}

void URLFetcherCore::OnCertificateRequested(
    URLRequest* request,
    SSLCertRequestInfo* cert_request_info) {
  DCHECK_EQ(request, request_.get());
  DCHECK(network_task_runner_->BelongsToCurrentThread());

  if (g_ignore_certificate_requests) {
    request->ContinueWithCertificate(NULL);
  } else {
    request->Cancel();
  }
}

void URLFetcherCore::OnReadCompleted(URLRequest* request,
                                     int bytes_read) {
  DCHECK(request == request_);
  DCHECK(network_task_runner_->BelongsToCurrentThread());

  if (!stopped_on_redirect_)
    url_ = request->url();
  URLRequestThrottlerManager* throttler_manager =
      request->context()->throttler_manager();
  if (throttler_manager) {
    url_throttler_entry_ = throttler_manager->RegisterRequestUrl(url_);
  }

  do {
    if (!request_->status().is_success() || bytes_read <= 0)
      break;

    current_response_bytes_ += bytes_read;
    InformDelegateDownloadProgress();

    const int result =
        WriteBuffer(new DrainableIOBuffer(buffer_.get(), bytes_read));
    if (result < 0) {
      // Write failed or waiting for write completion.
      return;
    }
  } while (request_->Read(buffer_.get(), kBufferSize, &bytes_read));

  const URLRequestStatus status = request_->status();

  if (status.is_success())
    request_->GetResponseCookies(&cookies_);

  // See comments re: HEAD requests in ReadResponse().
  if (!status.is_io_pending() || request_type_ == URLFetcher::HEAD) {
    status_ = status;
    ReleaseRequest();

    // No more data to write.
    const int result = response_writer_->Finish(
        base::Bind(&URLFetcherCore::DidFinishWriting, this));
    if (result != ERR_IO_PENDING)
      DidFinishWriting(result);
  }
}

void URLFetcherCore::CancelAll() {
  g_registry.Get().CancelAll();
}

int URLFetcherCore::GetNumFetcherCores() {
  return g_registry.Get().size();
}

void URLFetcherCore::SetEnableInterceptionForTests(bool enabled) {
  g_interception_enabled = enabled;
}

void URLFetcherCore::SetIgnoreCertificateRequests(bool ignored) {
  g_ignore_certificate_requests = ignored;
}

URLFetcherCore::~URLFetcherCore() {
  // |request_| should be NULL.  If not, it's unsafe to delete it here since we
  // may not be on the IO thread.
  DCHECK(!request_.get());
}

void URLFetcherCore::StartOnIOThread() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());

  if (!response_writer_)
    response_writer_.reset(new URLFetcherStringWriter);

  const int result = response_writer_->Initialize(
      base::Bind(&URLFetcherCore::DidInitializeWriter, this));
  if (result != ERR_IO_PENDING)
    DidInitializeWriter(result);
}

void URLFetcherCore::StartURLRequest() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());

  if (was_cancelled_) {
    // Since StartURLRequest() is posted as a *delayed* task, it may
    // run after the URLFetcher was already stopped.
    return;
  }

  DCHECK(request_context_getter_.get());
  DCHECK(!request_.get());

  g_registry.Get().AddURLFetcherCore(this);
  current_response_bytes_ = 0;
  request_ = request_context_getter_->GetURLRequestContext()->CreateRequest(
      original_url_, DEFAULT_PRIORITY, this, NULL);
  request_->set_stack_trace(stack_trace_);
  int flags = request_->load_flags() | load_flags_;
  if (!g_interception_enabled)
    flags = flags | LOAD_DISABLE_INTERCEPT;

  if (is_chunked_upload_)
    request_->EnableChunkedUpload();
  request_->SetLoadFlags(flags);
  request_->SetReferrer(referrer_);
  request_->set_referrer_policy(referrer_policy_);
  request_->set_first_party_for_cookies(first_party_for_cookies_.is_empty() ?
      original_url_ : first_party_for_cookies_);
  if (url_request_data_key_ && !url_request_create_data_callback_.is_null()) {
    request_->SetUserData(url_request_data_key_,
                          url_request_create_data_callback_.Run());
  }

  switch (request_type_) {
    case URLFetcher::GET:
      break;

    case URLFetcher::POST:
    case URLFetcher::PUT:
    case URLFetcher::PATCH:
      // Upload content must be set.
      DCHECK(is_chunked_upload_ || upload_content_set_);

      request_->set_method(
          request_type_ == URLFetcher::POST ? "POST" :
          request_type_ == URLFetcher::PUT ? "PUT" : "PATCH");
      if (!upload_content_type_.empty()) {
        extra_request_headers_.SetHeader(HttpRequestHeaders::kContentType,
                                         upload_content_type_);
      }
      if (!upload_content_.empty()) {
        scoped_ptr<UploadElementReader> reader(new UploadBytesElementReader(
            upload_content_.data(), upload_content_.size()));
        request_->set_upload(make_scoped_ptr(
            UploadDataStream::CreateWithReader(reader.Pass(), 0)));
      } else if (!upload_file_path_.empty()) {
        scoped_ptr<UploadElementReader> reader(
            new UploadFileElementReader(upload_file_task_runner_.get(),
                                        upload_file_path_,
                                        upload_range_offset_,
                                        upload_range_length_,
                                        base::Time()));
        request_->set_upload(make_scoped_ptr(
            UploadDataStream::CreateWithReader(reader.Pass(), 0)));
      }

      current_upload_bytes_ = -1;
      // TODO(kinaba): http://crbug.com/118103. Implement upload callback in the
      //  layer and avoid using timer here.
      upload_progress_checker_timer_.reset(
          new base::RepeatingTimer<URLFetcherCore>());
      upload_progress_checker_timer_->Start(
          FROM_HERE,
          base::TimeDelta::FromMilliseconds(kUploadProgressTimerInterval),
          this,
          &URLFetcherCore::InformDelegateUploadProgress);
      break;

    case URLFetcher::HEAD:
      request_->set_method("HEAD");
      break;

    case URLFetcher::DELETE_REQUEST:
      request_->set_method("DELETE");
      break;

    default:
      NOTREACHED();
  }

  if (!extra_request_headers_.IsEmpty())
    request_->SetExtraRequestHeaders(extra_request_headers_);

  request_->Start();
}

void URLFetcherCore::DidInitializeWriter(int result) {
  if (result != OK) {
    CancelURLRequest(result);
    delegate_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&URLFetcherCore::InformDelegateFetchIsComplete, this));
    return;
  }
  StartURLRequestWhenAppropriate();
}

void URLFetcherCore::StartURLRequestWhenAppropriate() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());

  if (was_cancelled_)
    return;

  DCHECK(request_context_getter_.get());

  int64 delay = 0LL;
  if (original_url_throttler_entry_.get() == NULL) {
    URLRequestThrottlerManager* manager =
        request_context_getter_->GetURLRequestContext()->throttler_manager();
    if (manager) {
      original_url_throttler_entry_ =
          manager->RegisterRequestUrl(original_url_);
    }
  }
  if (original_url_throttler_entry_.get() != NULL) {
    delay = original_url_throttler_entry_->ReserveSendingTimeForNextRequest(
        GetBackoffReleaseTime());
  }

  if (delay == 0) {
    StartURLRequest();
  } else {
    base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
        FROM_HERE, base::Bind(&URLFetcherCore::StartURLRequest, this),
        base::TimeDelta::FromMilliseconds(delay));
  }
}

void URLFetcherCore::CancelURLRequest(int error) {
  DCHECK(network_task_runner_->BelongsToCurrentThread());

  if (request_.get()) {
    request_->CancelWithError(error);
    ReleaseRequest();
  }

  // Set the error manually.
  // Normally, calling URLRequest::CancelWithError() results in calling
  // OnReadCompleted() with bytes_read = -1 via an asynchronous task posted by
  // URLRequestJob::NotifyDone(). But, because the request was released
  // immediately after being canceled, the request could not call
  // OnReadCompleted() which overwrites |status_| with the error status.
  status_.set_status(URLRequestStatus::CANCELED);
  status_.set_error(error);

  // Release the reference to the request context. There could be multiple
  // references to URLFetcher::Core at this point so it may take a while to
  // delete the object, but we cannot delay the destruction of the request
  // context.
  request_context_getter_ = NULL;
  first_party_for_cookies_ = GURL();
  url_request_data_key_ = NULL;
  url_request_create_data_callback_.Reset();
  was_cancelled_ = true;
}

void URLFetcherCore::OnCompletedURLRequest(
    base::TimeDelta backoff_delay) {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());

  // Save the status and backoff_delay so that delegates can read it.
  if (delegate_) {
    backoff_delay_ = backoff_delay;
    InformDelegateFetchIsComplete();
  }
}

void URLFetcherCore::InformDelegateFetchIsComplete() {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());
  if (delegate_)
    delegate_->OnURLFetchComplete(fetcher_);
}

void URLFetcherCore::NotifyMalformedContent() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());
  if (url_throttler_entry_.get() != NULL) {
    int status_code = response_code_;
    if (status_code == URLFetcher::RESPONSE_CODE_INVALID) {
      // The status code will generally be known by the time clients
      // call the |ReceivedContentWasMalformed()| function (which ends up
      // calling the current function) but if it's not, we need to assume
      // the response was successful so that the total failure count
      // used to calculate exponential back-off goes up.
      status_code = 200;
    }
    url_throttler_entry_->ReceivedContentWasMalformed(status_code);
  }
}

void URLFetcherCore::DidFinishWriting(int result) {
  if (result != OK) {
    CancelURLRequest(result);
    delegate_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&URLFetcherCore::InformDelegateFetchIsComplete, this));
    return;
  }
  // If the file was successfully closed, then the URL request is complete.
  RetryOrCompleteUrlFetch();
}

void URLFetcherCore::RetryOrCompleteUrlFetch() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());
  base::TimeDelta backoff_delay;

  // Checks the response from server.
  if (response_code_ >= 500 ||
      status_.error() == ERR_TEMPORARILY_THROTTLED) {
    // When encountering a server error, we will send the request again
    // after backoff time.
    ++num_retries_on_5xx_;

    // Note that backoff_delay may be 0 because (a) the
    // URLRequestThrottlerManager and related code does not
    // necessarily back off on the first error, (b) it only backs off
    // on some of the 5xx status codes, (c) not all URLRequestContexts
    // have a throttler manager.
    base::TimeTicks backoff_release_time = GetBackoffReleaseTime();
    backoff_delay = backoff_release_time - base::TimeTicks::Now();
    if (backoff_delay < base::TimeDelta())
      backoff_delay = base::TimeDelta();

    if (automatically_retry_on_5xx_ &&
        num_retries_on_5xx_ <= max_retries_on_5xx_) {
      StartOnIOThread();
      return;
    }
  } else {
    backoff_delay = base::TimeDelta();
  }

  // Retry if the request failed due to network changes.
  if (status_.error() == ERR_NETWORK_CHANGED &&
      num_retries_on_network_changes_ < max_retries_on_network_changes_) {
    ++num_retries_on_network_changes_;

    // Retry soon, after flushing all the current tasks which may include
    // further network change observers.
    network_task_runner_->PostTask(
        FROM_HERE, base::Bind(&URLFetcherCore::StartOnIOThread, this));
    return;
  }

  request_context_getter_ = NULL;
  first_party_for_cookies_ = GURL();
  url_request_data_key_ = NULL;
  url_request_create_data_callback_.Reset();
  bool posted = delegate_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(&URLFetcherCore::OnCompletedURLRequest, this, backoff_delay));

  // If the delegate message loop does not exist any more, then the delegate
  // should be gone too.
  DCHECK(posted || !delegate_);
}

void URLFetcherCore::ReleaseRequest() {
  upload_progress_checker_timer_.reset();
  request_.reset();
  g_registry.Get().RemoveURLFetcherCore(this);
}

base::TimeTicks URLFetcherCore::GetBackoffReleaseTime() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());

  if (original_url_throttler_entry_.get()) {
    base::TimeTicks original_url_backoff =
        original_url_throttler_entry_->GetExponentialBackoffReleaseTime();
    base::TimeTicks destination_url_backoff;
    if (url_throttler_entry_.get() != NULL &&
        original_url_throttler_entry_.get() != url_throttler_entry_.get()) {
      destination_url_backoff =
          url_throttler_entry_->GetExponentialBackoffReleaseTime();
    }

    return original_url_backoff > destination_url_backoff ?
        original_url_backoff : destination_url_backoff;
  } else {
    return base::TimeTicks();
  }
}

void URLFetcherCore::CompleteAddingUploadDataChunk(
    const std::string& content, bool is_last_chunk) {
  if (was_cancelled_) {
    // Since CompleteAddingUploadDataChunk() is posted as a *delayed* task, it
    // may run after the URLFetcher was already stopped.
    return;
  }
  DCHECK(is_chunked_upload_);
  DCHECK(request_.get());
  DCHECK(!content.empty());
  request_->AppendChunkToUpload(content.data(),
                                static_cast<int>(content.length()),
                                is_last_chunk);
}

int URLFetcherCore::WriteBuffer(scoped_refptr<DrainableIOBuffer> data) {
  while (data->BytesRemaining() > 0) {
    const int result = response_writer_->Write(
        data.get(),
        data->BytesRemaining(),
        base::Bind(&URLFetcherCore::DidWriteBuffer, this, data));
    if (result < 0) {
      if (result != ERR_IO_PENDING)
        DidWriteBuffer(data, result);
      return result;
    }
    data->DidConsume(result);
  }
  return OK;
}

void URLFetcherCore::DidWriteBuffer(scoped_refptr<DrainableIOBuffer> data,
                                    int result) {
  if (result < 0) {  // Handle errors.
    CancelURLRequest(result);
    response_writer_->Finish(base::Bind(&EmptyCompletionCallback));
    delegate_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&URLFetcherCore::InformDelegateFetchIsComplete, this));
    return;
  }

  // Continue writing.
  data->DidConsume(result);
  if (WriteBuffer(data) < 0)
    return;

  // Finished writing buffer_. Read some more, unless the request has been
  // cancelled and deleted.
  DCHECK_EQ(0, data->BytesRemaining());
  if (request_.get())
    ReadResponse();
}

void URLFetcherCore::ReadResponse() {
  // Some servers may treat HEAD requests as GET requests.  To free up the
  // network connection as soon as possible, signal that the request has
  // completed immediately, without trying to read any data back (all we care
  // about is the response code and headers, which we already have).
  int bytes_read = 0;
  if (request_->status().is_success() &&
      (request_type_ != URLFetcher::HEAD))
    request_->Read(buffer_.get(), kBufferSize, &bytes_read);
  OnReadCompleted(request_.get(), bytes_read);
}

void URLFetcherCore::InformDelegateUploadProgress() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());
  if (request_.get()) {
    int64 current = request_->GetUploadProgress().position();
    if (current_upload_bytes_ != current) {
      current_upload_bytes_ = current;
      int64 total = -1;
      if (!is_chunked_upload_) {
        total = static_cast<int64>(request_->GetUploadProgress().size());
        // Total may be zero if the UploadDataStream::Init has not been called
        // yet.  Don't send the upload progress until the size is initialized.
        if (!total)
          return;
      }
      delegate_task_runner_->PostTask(
          FROM_HERE,
          base::Bind(
              &URLFetcherCore::InformDelegateUploadProgressInDelegateThread,
              this, current, total));
    }
  }
}

void URLFetcherCore::InformDelegateUploadProgressInDelegateThread(
    int64 current, int64 total) {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());
  if (delegate_)
    delegate_->OnURLFetchUploadProgress(fetcher_, current, total);
}

void URLFetcherCore::InformDelegateDownloadProgress() {
  DCHECK(network_task_runner_->BelongsToCurrentThread());
  delegate_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(
          &URLFetcherCore::InformDelegateDownloadProgressInDelegateThread,
          this, current_response_bytes_, total_response_bytes_));
}

void URLFetcherCore::InformDelegateDownloadProgressInDelegateThread(
    int64 current, int64 total) {
  DCHECK(delegate_task_runner_->BelongsToCurrentThread());
  if (delegate_)
    delegate_->OnURLFetchDownloadProgress(fetcher_, current, total);
}

}  // namespace net
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root/net/url_request/url_fetcher_core.cc

DEFINITIONS
