include/basegfx/utils/systemdependentdata.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #pragma once
  11
  12 #include <sal/types.h>
  13 #include <basegfx/basegfxdllapi.h>
  14 #include <memory>
  15 #include <map>
  16
  17 namespace basegfx
  18 {
  19     class SystemDependentData;
  20     typedef std::shared_ptr<SystemDependentData> SystemDependentData_SharedPtr;
  21     typedef std::weak_ptr<SystemDependentData> SystemDependentData_WeakPtr;
  22
  23     class BASEGFX_DLLPUBLIC SystemDependentDataManager
  24     {
  25     private:
  26         // noncopyable
  27         SystemDependentDataManager(const SystemDependentDataManager&) = delete;
  28         SystemDependentDataManager& operator=(const SystemDependentDataManager&) = delete;
  29
  30     public:
  31         SystemDependentDataManager();
  32         virtual ~SystemDependentDataManager();
  33
  34         // call from (and with) SystemDependentData objects when start/end/touch
  35         // usage is needed
  36         virtual void startUsage(basegfx::SystemDependentData_SharedPtr& rData) = 0;
  37         virtual void endUsage(basegfx::SystemDependentData_SharedPtr& rData) = 0;
  38         virtual void touchUsage(basegfx::SystemDependentData_SharedPtr& rData) = 0;
  39
  40         // flush all buffered data (e.g. cleanup/shutdown)
  41         virtual void flushAll() = 0;
  42     };
  43
  44     class BASEGFX_DLLPUBLIC SystemDependentData
  45     {
  46     private:
  47         // noncopyable
  48         SystemDependentData(const SystemDependentData&) = delete;
  49         SystemDependentData& operator=(const SystemDependentData&) = delete;
  50
  51         // reference to a SystemDependentDataManager, probably
  52         // a single, globally used one, but not necessarily
  53         SystemDependentDataManager&     mrSystemDependentDataManager;
  54
  55         // Buffered CalculatedCycles, result of estimations using
  56         // getHoldCyclesInSeconds and estimateUsageInBytes, executed
  57         // using getHoldCyclesInSeconds. StartValue is 0 to detect
  58         // not-yet-calculated state
  59         sal_uInt32                      mnCalculatedCycles;
  60
  61     public:
  62         SystemDependentData(
  63             SystemDependentDataManager& rSystemDependentDataManager);
  64
  65         // CAUTION! It is VERY important to keep this base class
  66         // virtual, else typeid(class).hash_code() from derived classes
  67         // will NOT work what is ESSENTIAL for the SystemDependentData
  68         // mechanism to work properly. So DO NOT REMOVE virtual here, please.
  69         virtual ~SystemDependentData();
  70
  71         // allow access to call startUsage/endUsage/touchUsage
  72         // using getSystemDependentDataManager()
  73         SystemDependentDataManager& getSystemDependentDataManager() { return mrSystemDependentDataManager; }
  74
  75         // Calculate HoldCyclesInSeconds based on using
  76         // getHoldCyclesInSeconds and estimateUsageInBytes, the
  77         // result is created once on-demand and buffered in
  78         // mnCalculatedCycles
  79         sal_uInt32 calculateCombinedHoldCyclesInSeconds() const;
  80
  81         // Allow read access to the calculated cycles in seconds, this
  82         // can be e.g. used to determine if this instance got added
  83         sal_uInt32 getCombinedHoldCyclesInSeconds() const { return mnCalculatedCycles; }
  84
  85         // Size estimation of the entry in bytes - does not have to
  86         // be used, but should be. Default returns zero what
  87         // means there is no size estimation available. Override to
  88         // offer useful data if you want to have better caching.
  89         virtual sal_Int64 estimateUsageInBytes() const;
  90     };
  91
  92     class BASEGFX_DLLPUBLIC SystemDependentDataHolder
  93     {
  94     private:
  95         // Possibility to hold System-Dependent B2DPolygon-Representations
  96         std::map< size_t, SystemDependentData_WeakPtr > maSystemDependentReferences;
  97
  98         // noncopyable
  99         SystemDependentDataHolder(const SystemDependentDataHolder&) = delete;
 100         SystemDependentDataHolder& operator=(const SystemDependentDataHolder&) = delete;
 101
 102     public:
 103         SystemDependentDataHolder();
 104         virtual ~SystemDependentDataHolder();
 105
 106         void addOrReplaceSystemDependentData(SystemDependentData_SharedPtr& rData);
 107         SystemDependentData_SharedPtr getSystemDependentData(size_t hash_code) const;
 108     };
 109 } // end of namespace basegfx
 110
 111 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */