sd/source/ui/slidesorter/cache/SlsRequestQueue.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
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   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
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  12  *   contributor license agreements. See the NOTICE file distributed
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  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #pragma once
  21
  22 #include "SlsRequestPriorityClass.hxx"
  23 #include <cache/SlsCacheContext.hxx>
  24 #include <osl/mutex.hxx>
  25 #include <svx/sdrpageuser.hxx>
  26
  27 #include <memory>
  28
  29 namespace sd::slidesorter::cache
  30 {
  31 /** The request queue stores requests that are described by the Request
  32     sorted according to priority class and then priority.
  33 */
  34 class RequestQueue : public sdr::PageUser
  35 {
  36 public:
  37     explicit RequestQueue(SharedCacheContext pCacheContext);
  38     virtual ~RequestQueue();
  39
  40     /** Insert a request with highest or lowest priority in its priority
  41         class.  When the request is already present then it is first
  42         removed.  This effect is then a re-prioritization.
  43         @param aKey
  44             The request.
  45         @param eRequestClass
  46             The priority class in which to insert the request with highest
  47             or lowest priority.
  48         @param bInsertWithHighestPriority
  49             When this flag is <TRUE/> the request is inserted with highest
  50             priority in its class.  When <FALSE/> the request is inserted
  51             with lowest priority.
  52     */
  53     void AddRequest(CacheKey aKey, RequestPriorityClass eRequestClass);
  54
  55     /** Remove the specified request from the queue.
  56         @param aKey
  57             It is OK when the specified request is not a member of the
  58             queue.
  59     */
  60 #if OSL_DEBUG_LEVEL >= 2
  61     bool
  62 #else
  63     void
  64 #endif
  65     RemoveRequest(CacheKey aKey);
  66
  67     /** Change the priority class of the specified request.
  68     */
  69     void ChangeClass(CacheKey aKey, RequestPriorityClass eNewRequestClass);
  70
  71     /** Get the request with the highest priority int the highest priority class.
  72     */
  73     CacheKey GetFront();
  74
  75     // For debugging.
  76     RequestPriorityClass GetFrontPriorityClass();
  77
  78     /** Really a synonym for RemoveRequest(GetFront());
  79     */
  80     void PopFront();
  81
  82     /** Returns <TRUE/> when there is no element in the queue.
  83     */
  84     bool IsEmpty();
  85
  86     /** Remove all requests from the queue.  This resets the minimum and
  87         maximum priorities to their default values.
  88     */
  89     void Clear();
  90
  91     /** Return the mutex that guards the access to the priority queue.
  92     */
  93     ::osl::Mutex& GetMutex() { return maMutex; }
  94
  95     /** Ensure we don't hand out a page deleted before anyone got a
  96         chance to process it
  97     */
  98     virtual void PageInDestruction(const SdrPage& rPage) override;
  99
 100 private:
 101     ::osl::Mutex maMutex;
 102     class Container;
 103     std::unique_ptr<Container> mpRequestQueue;
 104     SharedCacheContext mpCacheContext;
 105
 106     /** A lower bound of the lowest priority of all elements in the queues.
 107         The start value is 0.  It is assigned and then decreased every time
 108         when an element is inserted or marked as the request with lowest
 109         priority.
 110     */
 111     int mnMinimumPriority;
 112     /** An upper bound of the highest priority of all elements in the queues.
 113         The start value is 1.  It is assigned and then increased every time
 114         when an element is inserted or marked as the request with highest
 115         priority.
 116     */
 117     int mnMaximumPriority;
 118 };
 119
 120 } // end of namespace ::sd::slidesorter::cache
 121
 122 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */