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 <map>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "base/synchronization/lock.h"
  13 #include "base/threading/platform_thread.h"
  14 #include "net/url_request/url_request.h"
  15
  16 template <typename T> struct DefaultSingletonTraits;
  17
  18 namespace net {
  19
  20 // This class is responsible for managing the set of protocol factories and
  21 // request interceptors that determine how an URLRequestJob gets created to
  22 // handle an URLRequest.
  23 //
  24 // MULTI-THREADING NOTICE:
  25 //   URLRequest is designed to have all consumers on a single thread, and
  26 //   so no attempt is made to support ProtocolFactory or Interceptor instances
  27 //   being registered/unregistered or in any way poked on multiple threads.
  28 //   However, we do support checking for supported schemes FROM ANY THREAD
  29 //   (i.e., it is safe to call SupportsScheme on any thread).
  30 //
  31 class URLRequestJobManager {
  32  public:
  33   // Returns the singleton instance.
  34   static URLRequestJobManager* GetInstance();
  35
  36   // Instantiate an URLRequestJob implementation based on the registered
  37   // interceptors and protocol factories.  This will always succeed in
  38   // returning a job unless we are--in the extreme case--out of memory.
  39   URLRequestJob* CreateJob(URLRequest* request,
  40                            NetworkDelegate* network_delegate) const;
  41
  42   // Allows interceptors to hijack the request after examining the new location
  43   // of a redirect. Returns NULL if no interceptor intervenes.
  44   URLRequestJob* MaybeInterceptRedirect(URLRequest* request,
  45                                         NetworkDelegate* network_delegate,
  46                                         const GURL& location) const;
  47
  48   // Allows interceptors to hijack the request after examining the response
  49   // status and headers. This is also called when there is no server response
  50   // at all to allow interception of failed requests due to network errors.
  51   // Returns NULL if no interceptor intervenes.
  52   URLRequestJob* MaybeInterceptResponse(
  53       URLRequest* request, NetworkDelegate* network_delegate) const;
  54
  55   // Returns true if there is a protocol factory registered for the given
  56   // scheme.  Note: also returns true if there is a built-in handler for the
  57   // given scheme.
  58   bool SupportsScheme(const std::string& scheme) const;
  59
  60   // Register a protocol factory associated with the given scheme.  The factory
  61   // parameter may be null to clear any existing association.  Returns the
  62   // previously registered protocol factory if any.
  63   URLRequest::ProtocolFactory* RegisterProtocolFactory(
  64       const std::string& scheme, URLRequest::ProtocolFactory* factory);
  65
  66   // Register/unregister a request interceptor.
  67   void RegisterRequestInterceptor(URLRequest::Interceptor* interceptor);
  68   void UnregisterRequestInterceptor(URLRequest::Interceptor* interceptor);
  69
  70  private:
  71   typedef std::map<std::string, URLRequest::ProtocolFactory*> FactoryMap;
  72   typedef std::vector<URLRequest::Interceptor*> InterceptorList;
  73   friend struct DefaultSingletonTraits<URLRequestJobManager>;
  74
  75   URLRequestJobManager();
  76   ~URLRequestJobManager();
  77
  78   // The first guy to call this function sets the allowed thread.  This way we
  79   // avoid needing to define that thread externally.  Since we expect all
  80   // callers to be on the same thread, we don't worry about threads racing to
  81   // set the allowed thread.
  82   bool IsAllowedThread() const {
  83 #if 0
  84     if (!allowed_thread_initialized_) {
  85       allowed_thread_ = base::PlatformThread::CurrentId();
  86       allowed_thread_initialized_ = true;
  87     }
  88     return allowed_thread_ == base::PlatformThread::CurrentId();
  89 #else
  90     // The previous version of this check used GetCurrentThread on Windows to
  91     // get thread handles to compare. Unfortunately, GetCurrentThread returns
  92     // a constant pseudo-handle (0xFFFFFFFE), and therefore IsAllowedThread
  93     // always returned true. The above code that's turned off is the correct
  94     // code, but causes the tree to turn red because some caller isn't
  95     // respecting our thread requirements. We're turning off the check for now;
  96     // bug http://b/issue?id=1338969 has been filed to fix things and turn the
  97     // check back on.
  98     return true;
  99   }
 100
 101   // We use this to assert that CreateJob and the registration functions all
 102   // run on the same thread.
 103   mutable base::PlatformThreadId allowed_thread_;
 104   mutable bool allowed_thread_initialized_;
 105 #endif
 106
 107   mutable base::Lock lock_;
 108   FactoryMap factories_;
 109   InterceptorList interceptors_;
 110
 111   DISALLOW_COPY_AND_ASSIGN(URLRequestJobManager);
 112 };
 113
 114 }  // namespace net
 115
 116 #endif  // NET_URL_REQUEST_URL_REQUEST_JOB_MANAGER_H_