components/webdata/common/web_data_request_manager.h

   1 // Copyright 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 // Chromium settings and storage represent user-selected preferences and
   6 // information and MUST not be extracted, overwritten or modified except
   7 // through Chromium defined APIs.
   8
   9 #ifndef COMPONENTS_WEBDATA_COMMON_WEB_DATA_REQUEST_MANAGER_H__
  10 #define COMPONENTS_WEBDATA_COMMON_WEB_DATA_REQUEST_MANAGER_H__
  11
  12 #include <map>
  13
  14 #include "base/memory/ref_counted.h"
  15 #include "base/synchronization/lock.h"
  16 #include "components/webdata/common/web_database_service.h"
  17 #include "components/webdata/common/web_data_results.h"
  18 #include "components/webdata/common/web_data_service_base.h"
  19 #include "components/webdata/common/web_data_service_consumer.h"
  20
  21 class WebDataService;
  22 class WebDataServiceConsumer;
  23 class WebDataRequestManager;
  24
  25 namespace base {
  26 class MessageLoop;
  27 }
  28
  29 //////////////////////////////////////////////////////////////////////////////
  30 //
  31 // Webdata requests
  32 //
  33 // Every request is processed using a request object. The object contains
  34 // both the request parameters and the results.
  35 //////////////////////////////////////////////////////////////////////////////
  36 class WebDataRequest {
  37  public:
  38   WebDataRequest(WebDataServiceConsumer* consumer,
  39                  WebDataRequestManager* manager);
  40
  41   virtual ~WebDataRequest();
  42
  43   WebDataServiceBase::Handle GetHandle() const;
  44
  45   // Retrieves the |consumer_| set in the constructor.
  46   WebDataServiceConsumer* GetConsumer() const;
  47
  48   // Retrieves the original message loop the of the request.
  49   base::MessageLoop* GetMessageLoop() const;
  50
  51   // Returns |true| if the request was cancelled via the |Cancel()| method.
  52   bool IsCancelled() const;
  53
  54   // This can be invoked from any thread. From this point we assume that
  55   // our consumer_ reference is invalid.
  56   void Cancel();
  57
  58   // Invoked when the request has been completed.
  59   void OnComplete();
  60
  61   // The result is owned by the request.
  62   void SetResult(scoped_ptr<WDTypedResult> r);
  63
  64   // Transfers ownership pof result to caller. Should only be called once per
  65   // result.
  66   scoped_ptr<WDTypedResult> GetResult();
  67
  68  private:
  69   // Used to notify manager if request is cancelled. Uses a raw ptr instead of
  70   // a ref_ptr so that it can be set to NULL when a request is cancelled.
  71   WebDataRequestManager* manager_;
  72
  73   // Tracks loop that the request originated on.
  74   base::MessageLoop* message_loop_;
  75
  76   // Identifier for this request.
  77   WebDataServiceBase::Handle handle_;
  78
  79   // A lock to protect against simultaneous cancellations of the request.
  80   // Cancellation affects both the |cancelled_| flag and |consumer_|.
  81   mutable base::Lock cancel_lock_;
  82   bool cancelled_;
  83
  84   // The originator of the service request.
  85   WebDataServiceConsumer* consumer_;
  86
  87   scoped_ptr<WDTypedResult> result_;
  88
  89   DISALLOW_COPY_AND_ASSIGN(WebDataRequest);
  90 };
  91
  92 //////////////////////////////////////////////////////////////////////////////
  93 //
  94 // Webdata Request Manager
  95 //
  96 // Tracks all WebDataRequests for a WebDataService.
  97 //
  98 // Note: This is an internal interface, not to be used outside of webdata/
  99 //////////////////////////////////////////////////////////////////////////////
 100 class WebDataRequestManager
 101     : public base::RefCountedThreadSafe<WebDataRequestManager> {
 102  public:
 103   WebDataRequestManager();
 104
 105   // Cancel any pending request.
 106   void CancelRequest(WebDataServiceBase::Handle h);
 107
 108   // Invoked by the WebDataService when |request| has been completed.
 109   void RequestCompleted(scoped_ptr<WebDataRequest> request);
 110
 111   // Register the request as a pending request.
 112   void RegisterRequest(WebDataRequest* request);
 113
 114   // Return the next request handle.
 115   int GetNextRequestHandle();
 116
 117  private:
 118   friend class base::RefCountedThreadSafe<WebDataRequestManager>;
 119
 120   ~WebDataRequestManager();
 121
 122   // This will notify the consumer in whatever thread was used to create this
 123   // request.
 124   void RequestCompletedOnThread(scoped_ptr<WebDataRequest> request);
 125
 126   // A lock to protect pending requests and next request handle.
 127   base::Lock pending_lock_;
 128
 129   // Next handle to be used for requests. Incremented for each use.
 130   WebDataServiceBase::Handle next_request_handle_;
 131
 132   typedef std::map<WebDataServiceBase::Handle, WebDataRequest*> RequestMap;
 133   RequestMap pending_requests_;
 134
 135   DISALLOW_COPY_AND_ASSIGN(WebDataRequestManager);
 136 };
 137
 138 #endif  // COMPONENTS_WEBDATA_COMMON_WEB_DATA_REQUEST_MANAGER_H__