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      1 // Copyright (c) 2006-2008 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 <vector>
     10 
     11 #include "base/lock.h"
     12 #include "base/platform_thread.h"
     13 #include "net/url_request/url_request.h"
     14 
     15 // This class is responsible for managing the set of protocol factories and
     16 // request interceptors that determine how an URLRequestJob gets created to
     17 // handle an URLRequest.
     18 //
     19 // MULTI-THREADING NOTICE:
     20 //   URLRequest is designed to have all consumers on a single thread, and so no
     21 //   attempt is made to support ProtocolFactory or Interceptor instances being
     22 //   registered/unregistered or in any way poked on multiple threads.  However,
     23 //   we do support checking for supported schemes FROM ANY THREAD (i.e., it is
     24 //   safe to call SupportsScheme on any thread).
     25 //
     26 class URLRequestJobManager {
     27  public:
     28   URLRequestJobManager();
     29 
     30   // Instantiate an URLRequestJob implementation based on the registered
     31   // interceptors and protocol factories.  This will always succeed in
     32   // returning a job unless we are--in the extreme case--out of memory.
     33   URLRequestJob* CreateJob(URLRequest* request) const;
     34 
     35   // Allows interceptors to hijack the request after examining the new location
     36   // of a redirect. Returns NULL if no interceptor intervenes.
     37   URLRequestJob* MaybeInterceptRedirect(URLRequest* request,
     38                                         const GURL& location) const;
     39 
     40   // Allows interceptors to hijack the request after examining the response
     41   // status and headers. This is also called when there is no server response
     42   // at all to allow interception of failed requests due to network errors.
     43   // Returns NULL if no interceptor intervenes.
     44   URLRequestJob* MaybeInterceptResponse(URLRequest* request) const;
     45 
     46   // Returns true if there is a protocol factory registered for the given
     47   // scheme.  Note: also returns true if there is a built-in handler for the
     48   // given scheme.
     49   bool SupportsScheme(const std::string& scheme) const;
     50 
     51   // Register a protocol factory associated with the given scheme.  The factory
     52   // parameter may be null to clear any existing association.  Returns the
     53   // previously registered protocol factory if any.
     54   URLRequest::ProtocolFactory* RegisterProtocolFactory(
     55       const std::string& scheme, URLRequest::ProtocolFactory* factory);
     56 
     57   // Register/unregister a request interceptor.
     58   void RegisterRequestInterceptor(URLRequest::Interceptor* interceptor);
     59   void UnregisterRequestInterceptor(URLRequest::Interceptor* interceptor);
     60 
     61  private:
     62   typedef std::map<std::string,URLRequest::ProtocolFactory*> FactoryMap;
     63   typedef std::vector<URLRequest::Interceptor*> InterceptorList;
     64 
     65   mutable Lock lock_;
     66   FactoryMap factories_;
     67   InterceptorList interceptors_;
     68 
     69 #ifndef NDEBUG
     70   // We use this to assert that CreateJob and the registration functions all
     71   // run on the same thread.
     72   mutable PlatformThreadId allowed_thread_;
     73   mutable bool allowed_thread_initialized_;
     74 
     75   // The first guy to call this function sets the allowed thread.  This way we
     76   // avoid needing to define that thread externally.  Since we expect all
     77   // callers to be on the same thread, we don't worry about threads racing to
     78   // set the allowed thread.
     79   bool IsAllowedThread() const {
     80 #if 0
     81     if (!allowed_thread_initialized_) {
     82       allowed_thread_ = PlatformThread::CurrentId();
     83       allowed_thread_initialized_ = true;
     84     }
     85     return allowed_thread_ == PlatformThread::CurrentId();
     86 #else
     87     // The previous version of this check used GetCurrentThread on Windows to
     88     // get thread handles to compare. Unfortunately, GetCurrentThread returns
     89     // a constant psuedo-handle (0xFFFFFFFE), and therefore IsAllowedThread
     90     // always returned true. The above code that's turned off is the correct
     91     // code, but causes the tree to turn red because some caller isn't
     92     // respecting our thread requirements. We're turning off the check for now;
     93     // bug http://b/issue?id=1338969 has been filed to fix things and turn the
     94     // check back on.
     95     return true;
     96 #endif
     97   }
     98 #endif
     99 
    100   DISALLOW_EVIL_CONSTRUCTORS(URLRequestJobManager);
    101 };
    102 
    103 #endif  // NET_URL_REQUEST_URL_REQUEST_JOB_MANAGER_H__
    104