ios/web/webui/url_data_source_ios_impl.cc

   1 // Copyright 2014 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 "ios/web/webui/url_data_source_ios_impl.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "base/memory/ref_counted_memory.h"
  10 #include "base/strings/string_util.h"
  11 #include "ios/web/public/url_data_source_ios.h"
  12 #include "ios/web/public/web_thread.h"
  13 #include "ios/web/webui/url_data_manager_ios_backend.h"
  14
  15 namespace web {
  16
  17 URLDataSourceIOSImpl::URLDataSourceIOSImpl(const std::string& source_name,
  18                                            URLDataSourceIOS* source)
  19     : source_name_(source_name), backend_(NULL), source_(source) {
  20 }
  21
  22 URLDataSourceIOSImpl::~URLDataSourceIOSImpl() {
  23 }
  24
  25 void URLDataSourceIOSImpl::SendResponse(int request_id,
  26                                         base::RefCountedMemory* bytes) {
  27   // Take a ref-pointer on entry so byte->Release() will always get called.
  28   scoped_refptr<base::RefCountedMemory> bytes_ptr(bytes);
  29   if (URLDataManagerIOS::IsScheduledForDeletion(this)) {
  30     // We're scheduled for deletion. Servicing the request would result in
  31     // this->AddRef being invoked, even though the ref count is 0 and 'this' is
  32     // about to be deleted. If the AddRef were allowed through, when 'this' is
  33     // released it would be deleted again.
  34     //
  35     // This scenario occurs with DataSources that make history requests. Such
  36     // DataSources do a history query in |StartDataRequest| and the request is
  37     // live until the object is deleted (history requests don't up the ref
  38     // count). This means it's entirely possible for the DataSource to invoke
  39     // |SendResponse| between the time when there are no more refs and the time
  40     // when the object is deleted.
  41     return;
  42   }
  43   web::WebThread::PostTask(
  44       web::WebThread::IO, FROM_HERE,
  45       base::Bind(&URLDataSourceIOSImpl::SendResponseOnIOThread, this,
  46                  request_id, bytes_ptr));
  47 }
  48
  49 void URLDataSourceIOSImpl::SendResponseOnIOThread(
  50     int request_id,
  51     scoped_refptr<base::RefCountedMemory> bytes) {
  52   DCHECK_CURRENTLY_ON_WEB_THREAD(web::WebThread::IO);
  53   if (backend_)
  54     backend_->DataAvailable(request_id, bytes.get());
  55 }
  56
  57 }  // namespace web