Home | History | Annotate | Download | only in url_request 
      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_
    103