runtime/WeakMapData.h

   1 /*
   2  * Copyright (C) 2013 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  23  * THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef WeakMapData_h
  27 #define WeakMapData_h
  28
  29 #include "JSCell.h"
  30 #include "Structure.h"
  31 #include <wtf/HashFunctions.h>
  32 #include <wtf/HashMap.h>
  33 #include <wtf/MathExtras.h>
  34
  35 namespace JSC {
  36
  37 class WeakMapData : public JSCell {
  38 public:
  39     typedef JSCell Base;
  40
  41     static WeakMapData* create(VM& vm)
  42     {
  43         WeakMapData* weakMapData = new (NotNull, allocateCell<WeakMapData>(vm.heap)) WeakMapData(vm);
  44         weakMapData->finishCreation(vm);
  45         return weakMapData;
  46     }
  47
  48     static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
  49     {
  50         return Structure::create(vm, globalObject, prototype, TypeInfo(CompoundType, StructureFlags), info());
  51     }
  52
  53     static const bool needsDestruction = true;
  54     static const bool hasImmortalStructure = true;
  55
  56     void set(VM&, JSObject*, JSValue);
  57     JSValue get(JSObject*);
  58     bool remove(JSObject*);
  59     bool contains(JSObject*);
  60     void clear();
  61
  62     DECLARE_INFO;
  63
  64     static const unsigned StructureFlags = OverridesVisitChildren | StructureIsImmortal | Base::StructureFlags;
  65
  66 private:
  67     WeakMapData(VM&);
  68     static void destroy(JSCell*);
  69     static void visitChildren(JSCell*, SlotVisitor&);
  70     void finishCreation(VM&);
  71
  72     class DeadKeyCleaner : public UnconditionalFinalizer, public WeakReferenceHarvester {
  73     public:
  74         DeadKeyCleaner(WeakMapData* target)
  75             : m_target(target)
  76         {
  77         }
  78     private:
  79         virtual void visitWeakReferences(SlotVisitor&) override;
  80         virtual void finalizeUnconditionally() override;
  81         int m_liveKeyCount;
  82         WeakMapData* m_target;
  83     };
  84     DeadKeyCleaner m_deadKeyCleaner;
  85     typedef HashMap<JSObject*, WriteBarrier<Unknown>> MapType;
  86     MapType m_map;
  87 };
  88
  89 }
  90
  91 #endif /* !defined(WeakMapData_h) */