net/url_request/url_request_job_manager.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_JOB_MANAGER_H_
   6 #define NET_URL_REQUEST_URL_REQUEST_JOB_MANAGER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/synchronization/lock.h"
  12 #include "base/threading/platform_thread.h"
  13 #include "net/url_request/url_request.h"
  14
  15 template <typename T> struct DefaultSingletonTraits;
  16
  17 namespace net {
  18
  19 // This class is responsible for managing the set of protocol factories and
  20 // request interceptors that determine how an URLRequestJob gets created to
  21 // handle an URLRequest.
  22 //
  23 // MULTI-THREADING NOTICE:
  24 //   URLRequest is designed to have all consumers on a single thread, and
  25 //   so no attempt is made to support Interceptor instances being
  26 //   registered/unregistered or in any way poked on multiple threads.
  27 class URLRequestJobManager {
  28  public:
  29   // Returns the singleton instance.
  30   static URLRequestJobManager* GetInstance();
  31
  32   // Instantiate an URLRequestJob implementation based on the registered
  33   // interceptors and protocol factories.  This will always succeed in
  34   // returning a job unless we are--in the extreme case--out of memory.
  35   URLRequestJob* CreateJob(URLRequest* request,
  36                            NetworkDelegate* network_delegate) const;
  37
  38   // Allows interceptors to hijack the request after examining the new location
  39   // of a redirect. Returns NULL if no interceptor intervenes.
  40   URLRequestJob* MaybeInterceptRedirect(URLRequest* request,
  41                                         NetworkDelegate* network_delegate,
  42                                         const GURL& location) const;
  43
  44   // Allows interceptors to hijack the request after examining the response
  45   // status and headers. This is also called when there is no server response
  46   // at all to allow interception of failed requests due to network errors.
  47   // Returns NULL if no interceptor intervenes.
  48   URLRequestJob* MaybeInterceptResponse(
  49       URLRequest* request, NetworkDelegate* network_delegate) const;
  50
  51   // Returns true if the manager has a built-in handler for |scheme|.
  52   static bool SupportsScheme(const std::string& scheme);
  53
  54   // Register/unregister a request interceptor.
  55   void RegisterRequestInterceptor(URLRequest::Interceptor* interceptor);
  56   void UnregisterRequestInterceptor(URLRequest::Interceptor* interceptor);
  57
  58  private:
  59   typedef std::vector<URLRequest::Interceptor*> InterceptorList;
  60   friend struct DefaultSingletonTraits<URLRequestJobManager>;
  61
  62   URLRequestJobManager();
  63   ~URLRequestJobManager();
  64
  65   // The first guy to call this function sets the allowed thread.  This way we
  66   // avoid needing to define that thread externally.  Since we expect all
  67   // callers to be on the same thread, we don't worry about threads racing to
  68   // set the allowed thread.
  69   bool IsAllowedThread() const {
  70 #if 0
  71     if (!allowed_thread_initialized_) {
  72       allowed_thread_ = base::PlatformThread::CurrentId();
  73       allowed_thread_initialized_ = true;
  74     }
  75     return allowed_thread_ == base::PlatformThread::CurrentId();
  76 #else
  77     // The previous version of this check used GetCurrentThread on Windows to
  78     // get thread handles to compare. Unfortunately, GetCurrentThread returns
  79     // a constant pseudo-handle (0xFFFFFFFE), and therefore IsAllowedThread
  80     // always returned true. The above code that's turned off is the correct
  81     // code, but causes the tree to turn red because some caller isn't
  82     // respecting our thread requirements. We're turning off the check for now;
  83     // bug http://b/issue?id=1338969 has been filed to fix things and turn the
  84     // check back on.
  85     return true;
  86   }
  87
  88   // We use this to assert that CreateJob and the registration functions all
  89   // run on the same thread.
  90   mutable base::PlatformThreadId allowed_thread_;
  91   mutable bool allowed_thread_initialized_;
  92 #endif
  93
  94   mutable base::Lock lock_;
  95   InterceptorList interceptors_;
  96
  97   DISALLOW_COPY_AND_ASSIGN(URLRequestJobManager);
  98 };
  99
 100 }  // namespace net
 101
 102 #endif  // NET_URL_REQUEST_URL_REQUEST_JOB_MANAGER_H_