net/url_request/url_request_context_getter.h

   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 #ifndef NET_URL_REQUEST_URL_REQUEST_CONTEXT_GETTER_H_
   6 #define NET_URL_REQUEST_URL_REQUEST_CONTEXT_GETTER_H_
   7
   8 #include "base/macros.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/observer_list.h"
  11 #include "base/sequenced_task_runner_helpers.h"
  12 #include "net/base/net_export.h"
  13
  14 namespace base {
  15 class SingleThreadTaskRunner;
  16 }  // namespace base
  17
  18 namespace net {
  19 class CookieStore;
  20 class URLRequestContext;
  21 class URLRequestContextGetterObserver;
  22
  23 struct URLRequestContextGetterTraits;
  24
  25 // Interface for retrieving an URLRequestContext.
  26 class NET_EXPORT URLRequestContextGetter
  27     : public base::RefCountedThreadSafe<URLRequestContextGetter,
  28                                         URLRequestContextGetterTraits> {
  29  public:
  30   // Returns the URLRequestContextGetter's URLRequestContext. Must only be
  31   // called on the network task runner. Once NotifyContextShuttingDown() is
  32   // invoked, must always return nullptr.
  33   virtual URLRequestContext* GetURLRequestContext() = 0;
  34
  35   // Returns a SingleThreadTaskRunner corresponding to the thread on
  36   // which the network IO happens (the thread on which the returned
  37   // URLRequestContext may be used).
  38   virtual scoped_refptr<base::SingleThreadTaskRunner>
  39       GetNetworkTaskRunner() const = 0;
  40
  41   // Adds / removes an observer to watch for shutdown of |this|'s context. Must
  42   // only be called on network thread. May not be called once
  43   // GetURLRequestContext() starts returning nullptr.
  44   void AddObserver(URLRequestContextGetterObserver* observer);
  45   void RemoveObserver(URLRequestContextGetterObserver* observer);
  46
  47  protected:
  48   friend class base::RefCountedThreadSafe<URLRequestContextGetter,
  49                                           URLRequestContextGetterTraits>;
  50   friend class base::DeleteHelper<URLRequestContextGetter>;
  51   friend struct URLRequestContextGetterTraits;
  52
  53   URLRequestContextGetter();
  54   virtual ~URLRequestContextGetter();
  55
  56   // Called to indicate the URLRequestContext is about to be shutdown, so
  57   // observers need to abort any URLRequests they own.  The implementation of
  58   // this class is responsible for making sure this gets called.
  59   //
  60   // Must be called once and only once *before* context tear down begins, so any
  61   // pending requests can be torn down safely. Right before calling this method,
  62   // subclasses must ensure GetURLRequestContext returns nullptr, to protect
  63   // against reentrancy.
  64   void NotifyContextShuttingDown();
  65
  66  private:
  67   // OnDestruct is used to ensure deletion on the thread on which the request
  68   // IO happens.
  69   void OnDestruct() const;
  70
  71   base::ObserverList<URLRequestContextGetterObserver> observer_list_;
  72
  73   DISALLOW_COPY_AND_ASSIGN(URLRequestContextGetter);
  74 };
  75
  76 struct URLRequestContextGetterTraits {
  77   static void Destruct(const URLRequestContextGetter* context_getter) {
  78     context_getter->OnDestruct();
  79   }
  80 };
  81
  82 // For use in shimming a URLRequestContext into a URLRequestContextGetter.
  83 class NET_EXPORT TrivialURLRequestContextGetter
  84     : public URLRequestContextGetter {
  85  public:
  86   TrivialURLRequestContextGetter(
  87       URLRequestContext* context,
  88       const scoped_refptr<base::SingleThreadTaskRunner>& main_task_runner);
  89
  90  // URLRequestContextGetter implementation:
  91  URLRequestContext* GetURLRequestContext() override;
  92
  93   scoped_refptr<base::SingleThreadTaskRunner> GetNetworkTaskRunner()
  94       const override;
  95
  96  private:
  97   ~TrivialURLRequestContextGetter() override;
  98
  99   URLRequestContext* context_;
 100   const scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 101
 102   DISALLOW_COPY_AND_ASSIGN(TrivialURLRequestContextGetter);
 103 };
 104
 105 }  // namespace net
 106
 107 #endif  // NET_URL_REQUEST_URL_REQUEST_CONTEXT_GETTER_H_