1 files changed, 134 insertions, 0 deletions
diff --git a/include/basegfx/utils/systemdependentdata.hxx b/include/basegfx/utils/systemdependentdata.hxx
new file mode 100644
index 000000000..120e39a0e
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+++ b/include/basegfx/utils/systemdependentdata.hxx
@@ -0,0 +1,134 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include <sal/types.h>
+#include <basegfx/basegfxdllapi.h>
+#include <memory>
+#include <map>
+#include <set>
+
+namespace basegfx
+{
+    class SystemDependentData;
+    typedef std::shared_ptr<SystemDependentData> SystemDependentData_SharedPtr;
+    typedef std::weak_ptr<SystemDependentData> SystemDependentData_WeakPtr;
+
+    class BASEGFX_DLLPUBLIC SystemDependentDataManager
+    {
+    private:
+        // noncopyable
+        SystemDependentDataManager(const SystemDependentDataManager&) = delete;
+        SystemDependentDataManager& operator=(const SystemDependentDataManager&) = delete;
+
+    public:
+        SystemDependentDataManager();
+        virtual ~SystemDependentDataManager();
+
+        // call from (and with) SystemDependentData objects when start/end/touch
+        // usage is needed
+        virtual void startUsage(basegfx::SystemDependentData_SharedPtr& rData) = 0;
+        virtual void endUsage(basegfx::SystemDependentData_SharedPtr& rData) = 0;
+        virtual void touchUsage(basegfx::SystemDependentData_SharedPtr& rData) = 0;
+
+        // flush all buffered data (e.g. cleanup/shutdown)
+        virtual void flushAll() = 0;
+    };
+
+    class BASEGFX_DLLPUBLIC MinimalSystemDependentDataManager final : public SystemDependentDataManager
+    {
+    private:
+        // example of a minimal SystemDependentDataManager. It *needs to hold*
+        // a SystemDependentData_SharedPtr while SystemDependentDataHolder's will
+        // use a SystemDependentData_WeakPtr. When the held SystemDependentData_SharedPtr
+        // is deleted, the corresponding SystemDependentData_WeakPtr will get void.
+        // To make this work, a minimal SystemDependentDataManager *has* to hold at
+        // least that one SystemDependentData_SharedPtr.
+        // That SystemDependentData_SharedPtr may be (e.g. Timer-based or resource-based)
+        // be freed then. This minimal implementation does never free it, so all stay valid.
+        // The instances may still be removed by endUsage calls, but there is no
+        // caching/buffering mechanism involved here at all. It's an example, but
+        // not used - better use an advanced derivation of SystemDependentDataManager
+        std::set< SystemDependentData_SharedPtr >   maSystemDependentDataReferences;
+
+    public:
+        MinimalSystemDependentDataManager();
+        virtual ~MinimalSystemDependentDataManager() override;
+
+        virtual void startUsage(basegfx::SystemDependentData_SharedPtr& rData) override;
+        virtual void endUsage(basegfx::SystemDependentData_SharedPtr& rData) override;
+        virtual void touchUsage(basegfx::SystemDependentData_SharedPtr& rData) override;
+        virtual void flushAll() override;
+    };
+
+    class BASEGFX_DLLPUBLIC SystemDependentData
+    {
+    private:
+        // noncopyable
+        SystemDependentData(const SystemDependentData&) = delete;
+        SystemDependentData& operator=(const SystemDependentData&) = delete;
+
+        // reference to a SystemDependentDataManager, probably
+        // a single, globally used one, but not necessarily
+        SystemDependentDataManager&     mrSystemDependentDataManager;
+
+        // Buffered CalculatedCycles, result of estimations using
+        // getHoldCyclesInSeconds and estimateUsageInBytes, executed
+        // using getHoldCyclesInSeconds. StartValue is 0 to detect
+        // not-yet-calculated state
+        sal_uInt32                      mnCalculatedCycles;
+
+    public:
+        SystemDependentData(
+            SystemDependentDataManager& rSystemDependentDataManager);
+
+        // CAUTION! It is VERY important to keep this base class
+        // virtual, else typeid(class).hash_code() from derived classes
+        // will NOT work what is ESSENTIAL for the SystemDependentData
+        // mechanism to work properly. So DO NOT REMOVE virtual here, please.
+        virtual ~SystemDependentData();
+
+        // allow access to call startUsage/endUsage/touchUsage
+        // using getSystemDependentDataManager()
+        SystemDependentDataManager& getSystemDependentDataManager() { return mrSystemDependentDataManager; }
+
+        // Calculate HoldCyclesInSeconds based on using
+        // getHoldCyclesInSeconds and estimateUsageInBytes, the
+        // result is created once on-demand and buffered in
+        // mnCalculatedCycles
+        sal_uInt32 calculateCombinedHoldCyclesInSeconds() const;
+
+        // Size estimation of the entry in bytes - does not have to
+        // be used, but should be. Default returns zero what
+        // means there is no size estimation available. Override to
+        // offer useful data if you want to have better caching.
+        virtual sal_Int64 estimateUsageInBytes() const;
+    };
+
+    class BASEGFX_DLLPUBLIC SystemDependentDataHolder
+    {
+    private:
+        // Possibility to hold System-Dependent B2DPolygon-Representations
+        std::map< size_t, SystemDependentData_WeakPtr > maSystemDependentReferences;
+
+        // noncopyable
+        SystemDependentDataHolder(const SystemDependentDataHolder&) = delete;
+        SystemDependentDataHolder& operator=(const SystemDependentDataHolder&) = delete;
+
+    public:
+        SystemDependentDataHolder();
+        virtual ~SystemDependentDataHolder();
+
+        void addOrReplaceSystemDependentData(SystemDependentData_SharedPtr& rData);
+        SystemDependentData_SharedPtr getSystemDependentData(size_t hash_code) const;
+    };
+} // end of namespace basegfx
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */