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engines/hpl1/engine/libraries/angelscript/sources/as_gc.h

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+/*
+   AngelCode Scripting Library
+   Copyright (c) 2003-2018 Andreas Jonsson
+
+   This software is provided 'as-is', without any express or implied
+   warranty. In no event will the authors be held liable for any
+   damages arising from the use of this software.
+
+   Permission is granted to anyone to use this software for any
+   purpose, including commercial applications, and to alter it and
+   redistribute it freely, subject to the following restrictions:
+
+   1. The origin of this software must not be misrepresented; you
+      must not claim that you wrote the original software. If you use
+      this software in a product, an acknowledgment in the product
+      documentation would be appreciated but is not required.
+
+   2. Altered source versions must be plainly marked as such, and
+      must not be misrepresented as being the original software.
+
+   3. This notice may not be removed or altered from any source
+      distribution.
+
+   The original version of this library can be located at:
+   http://www.angelcode.com/angelscript/
+
+   Andreas Jonsson
+   andreas@angelcode.com
+*/
+
+
+//
+// as_gc.h
+//
+// The garbage collector is used to resolve cyclic references
+//
+
+
+
+#ifndef AS_GC_H
+#define AS_GC_H
+
+#include "as_config.h"
+#include "as_memory.h"
+#include "as_map.h"
+#include "as_thread.h"
+
+BEGIN_AS_NAMESPACE
+
+class asCScriptEngine;
+class asCObjectType;
+
+class asCGarbageCollector {
+public:
+	asCGarbageCollector();
+	~asCGarbageCollector();
+
+	int    GarbageCollect(asDWORD flags, asUINT iterations);
+	void   GetStatistics(asUINT *currentSize, asUINT *totalDestroyed, asUINT *totalDetected, asUINT *newObjects, asUINT *totalNewDestroyed) const;
+	void   GCEnumCallback(void *reference);
+	int    AddScriptObjectToGC(void *obj, asCObjectType *objType);
+	int    GetObjectInGC(asUINT idx, asUINT *seqNbr, void **obj, asITypeInfo **type);
+
+	int    ReportAndReleaseUndestroyedObjects();
+
+	asCScriptEngine *engine;
+
+	// Callback for when circular reference are detected
+	asCIRCULARREFFUNC_t circularRefDetectCallbackFunc;
+	void               *circularRefDetectCallbackParam;
+
+protected:
+	struct asSObjTypePair {
+		void *obj;
+		asCObjectType *type;
+		asUINT seqNbr;
+	};
+	struct asSIntTypePair {
+		int i;
+		asCObjectType *type;
+	};
+	typedef asSMapNode<void *, asSIntTypePair> asSMapNode_t;
+
+	enum egcDestroyState {
+		destroyGarbage_init = 0,
+		destroyGarbage_loop,
+		destroyGarbage_haveMore
+	};
+
+	enum egcDetectState {
+		clearCounters_init = 0,
+		clearCounters_loop,
+		buildMap_init,
+		buildMap_loop,
+		countReferences_init,
+		countReferences_loop,
+		detectGarbage_init,
+		detectGarbage_loop1,
+		detectGarbage_loop2,
+		verifyUnmarked_init,
+		verifyUnmarked_loop,
+		breakCircles_init,
+		breakCircles_loop,
+		breakCircles_haveGarbage
+	};
+
+	int            DestroyNewGarbage();
+	int            DestroyOldGarbage();
+	int            IdentifyGarbageWithCyclicRefs();
+	asSObjTypePair GetNewObjectAtIdx(int idx);
+	asSObjTypePair GetOldObjectAtIdx(int idx);
+	void           RemoveNewObjectAtIdx(int idx);
+	void           RemoveOldObjectAtIdx(int idx);
+	void           MoveObjectToOldList(int idx);
+	void           MoveAllObjectsToOldList();
+
+	// Holds all the objects known by the garbage collector
+	asCArray<asSObjTypePair>           gcNewObjects;
+	asCArray<asSObjTypePair>           gcOldObjects;
+
+	// This array temporarily holds references to objects known to be live objects
+	asCArray<void *>                    liveObjects;
+
+	// This map holds objects currently being searched for cyclic references, it also holds a
+	// counter that gives the number of references to the object that the GC can't reach
+	asCMap<void *, asSIntTypePair>      gcMap;
+
+	// State variables
+	egcDestroyState                    destroyNewState;
+	egcDestroyState                    destroyOldState;
+	asUINT                             destroyNewIdx;
+	asUINT                             destroyOldIdx;
+	asUINT                             numDestroyed;
+	asUINT                             numNewDestroyed;
+	egcDetectState                     detectState;
+	asUINT                             detectIdx;
+	asUINT                             numDetected;
+	asUINT                             numAdded;
+	asUINT                             seqAtSweepStart[3];
+	asSMapNode_t                      *gcMapCursor;
+	bool                               isProcessing;
+
+	// We'll keep a pool of nodes to avoid allocating memory all the time
+	asSMapNode_t            *GetNode(void *obj, asSIntTypePair it);
+	void                     ReturnNode(asSMapNode_t *node);
+	asCArray<asSMapNode_t *>  freeNodes;
+
+	// Critical section for multithreaded access
+	DECLARECRITICALSECTION(gcCritical)   // Used for adding/removing objects
+	DECLARECRITICALSECTION(gcCollecting) // Used for processing
+};
+
+END_AS_NAMESPACE
+
+#endif