content/browser/loader/detachable_resource_handler.cc

   1 // Copyright 2013 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 "content/browser/loader/detachable_resource_handler.h"
   6
   7 #include "base/logging.h"
   8 #include "base/time/time.h"
   9 #include "content/browser/loader/resource_request_info_impl.h"
  10 #include "net/base/io_buffer.h"
  11 #include "net/base/net_errors.h"
  12 #include "net/url_request/url_request.h"
  13 #include "net/url_request/url_request_status.h"
  14
  15 namespace {
  16 // This matches the maximum allocation size of AsyncResourceHandler.
  17 const int kReadBufSize = 32 * 1024;
  18 }
  19
  20 namespace content {
  21
  22 DetachableResourceHandler::DetachableResourceHandler(
  23     net::URLRequest* request,
  24     base::TimeDelta cancel_delay,
  25     scoped_ptr<ResourceHandler> next_handler)
  26     : ResourceHandler(request),
  27       next_handler_(next_handler.Pass()),
  28       cancel_delay_(cancel_delay),
  29       is_deferred_(false),
  30       is_finished_(false) {
  31   GetRequestInfo()->set_detachable_handler(this);
  32 }
  33
  34 DetachableResourceHandler::~DetachableResourceHandler() {
  35   // Cleanup back-pointer stored on the request info.
  36   GetRequestInfo()->set_detachable_handler(NULL);
  37 }
  38
  39 void DetachableResourceHandler::Detach() {
  40   if (is_detached())
  41     return;
  42
  43   if (!is_finished_) {
  44     // Simulate a cancel on the next handler before destroying it.
  45     net::URLRequestStatus status(net::URLRequestStatus::CANCELED,
  46                                  net::ERR_ABORTED);
  47     bool defer_ignored = false;
  48     next_handler_->OnResponseCompleted(status, std::string(), &defer_ignored);
  49     DCHECK(!defer_ignored);
  50     // If |next_handler_| were to defer its shutdown in OnResponseCompleted,
  51     // this would destroy it anyway. Fortunately, AsyncResourceHandler never
  52     // does this anyway, so DCHECK it. MimeTypeResourceHandler and RVH shutdown
  53     // already ignore deferred ResourceHandler shutdown, but
  54     // DetachableResourceHandler and the detach-on-renderer-cancel logic
  55     // introduces a case where this occurs when the renderer cancels a resource.
  56   }
  57   // A OnWillRead / OnReadCompleted pair may still be in progress, but
  58   // OnWillRead passes back a scoped_refptr, so downstream handler's buffer will
  59   // survive long enough to complete that read. From there, future reads will
  60   // drain into |read_buffer_|. (If |next_handler_| is an AsyncResourceHandler,
  61   // the net::IOBuffer takes a reference to the ResourceBuffer which owns the
  62   // shared memory.)
  63   next_handler_.reset();
  64
  65   // Time the request out if it takes too long.
  66   detached_timer_.reset(new base::OneShotTimer<DetachableResourceHandler>());
  67   detached_timer_->Start(
  68       FROM_HERE, cancel_delay_, this, &DetachableResourceHandler::Cancel);
  69
  70   // Resume if necessary. The request may have been deferred, say, waiting on a
  71   // full buffer in AsyncResourceHandler. Now that it has been detached, resume
  72   // and drain it.
  73   if (is_deferred_) {
  74     // The nested ResourceHandler may have logged that it's blocking the
  75     // request.  Log it as no longer doing so, to avoid a DCHECK on resume.
  76     request()->LogUnblocked();
  77     Resume();
  78   }
  79 }
  80
  81 void DetachableResourceHandler::SetController(ResourceController* controller) {
  82   ResourceHandler::SetController(controller);
  83
  84   // Intercept the ResourceController for downstream handlers to keep track of
  85   // whether the request is deferred.
  86   if (next_handler_)
  87     next_handler_->SetController(this);
  88 }
  89
  90 bool DetachableResourceHandler::OnRequestRedirected(
  91     const net::RedirectInfo& redirect_info,
  92     ResourceResponse* response,
  93     bool* defer) {
  94   DCHECK(!is_deferred_);
  95
  96   if (!next_handler_)
  97     return true;
  98
  99   bool ret = next_handler_->OnRequestRedirected(
 100       redirect_info, response, &is_deferred_);
 101   *defer = is_deferred_;
 102   return ret;
 103 }
 104
 105 bool DetachableResourceHandler::OnResponseStarted(ResourceResponse* response,
 106                                                   bool* defer) {
 107   DCHECK(!is_deferred_);
 108
 109   if (!next_handler_)
 110     return true;
 111
 112   bool ret =
 113       next_handler_->OnResponseStarted(response, &is_deferred_);
 114   *defer = is_deferred_;
 115   return ret;
 116 }
 117
 118 bool DetachableResourceHandler::OnWillStart(const GURL& url, bool* defer) {
 119   DCHECK(!is_deferred_);
 120
 121   if (!next_handler_)
 122     return true;
 123
 124   bool ret = next_handler_->OnWillStart(url, &is_deferred_);
 125   *defer = is_deferred_;
 126   return ret;
 127 }
 128
 129 bool DetachableResourceHandler::OnBeforeNetworkStart(const GURL& url,
 130                                                      bool* defer) {
 131   DCHECK(!is_deferred_);
 132
 133   if (!next_handler_)
 134     return true;
 135
 136   bool ret =
 137       next_handler_->OnBeforeNetworkStart(url, &is_deferred_);
 138   *defer = is_deferred_;
 139   return ret;
 140 }
 141
 142 bool DetachableResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
 143                                            int* buf_size,
 144                                            int min_size) {
 145   if (!next_handler_) {
 146     DCHECK_EQ(-1, min_size);
 147     if (!read_buffer_.get())
 148       read_buffer_ = new net::IOBuffer(kReadBufSize);
 149     *buf = read_buffer_;
 150     *buf_size = kReadBufSize;
 151     return true;
 152   }
 153
 154   return next_handler_->OnWillRead(buf, buf_size, min_size);
 155 }
 156
 157 bool DetachableResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
 158   DCHECK(!is_deferred_);
 159
 160   if (!next_handler_)
 161     return true;
 162
 163   bool ret =
 164       next_handler_->OnReadCompleted(bytes_read, &is_deferred_);
 165   *defer = is_deferred_;
 166   return ret;
 167 }
 168
 169 void DetachableResourceHandler::OnResponseCompleted(
 170     const net::URLRequestStatus& status,
 171     const std::string& security_info,
 172     bool* defer) {
 173   // No DCHECK(!is_deferred_) as the request may have been cancelled while
 174   // deferred.
 175
 176   if (!next_handler_)
 177     return;
 178
 179   is_finished_ = true;
 180
 181   next_handler_->OnResponseCompleted(status, security_info, &is_deferred_);
 182   *defer = is_deferred_;
 183 }
 184
 185 void DetachableResourceHandler::OnDataDownloaded(int bytes_downloaded) {
 186   if (!next_handler_)
 187     return;
 188
 189   next_handler_->OnDataDownloaded(bytes_downloaded);
 190 }
 191
 192 void DetachableResourceHandler::Resume() {
 193   DCHECK(is_deferred_);
 194   is_deferred_ = false;
 195   controller()->Resume();
 196 }
 197
 198 void DetachableResourceHandler::Cancel() {
 199   controller()->Cancel();
 200 }
 201
 202 void DetachableResourceHandler::CancelAndIgnore() {
 203   controller()->CancelAndIgnore();
 204 }
 205
 206 void DetachableResourceHandler::CancelWithError(int error_code) {
 207   controller()->CancelWithError(error_code);
 208 }
 209
 210 }  // namespace content