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      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__
    139