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