runtime/SparseArrayValueMap.h

   1 /*
   2  * Copyright (C) 2011, 2012 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. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef SparseArrayValueMap_h
  27 #define SparseArrayValueMap_h
  28
  29 #include "JSCell.h"
  30 #include "JSTypeInfo.h"
  31 #include "PropertyDescriptor.h"
  32 #include "PutDirectIndexMode.h"
  33 #include "WriteBarrier.h"
  34 #include <wtf/HashMap.h>
  35
  36 namespace JSC {
  37
  38 class SparseArrayValueMap;
  39
  40 struct SparseArrayEntry : public WriteBarrier<Unknown> {
  41     typedef WriteBarrier<Unknown> Base;
  42
  43     SparseArrayEntry() : attributes(0) { }
  44
  45     JSValue get(ExecState*, JSObject*) const;
  46     void get(JSObject*, PropertySlot&) const;
  47     void get(PropertyDescriptor&) const;
  48     void put(ExecState*, JSValue thisValue, SparseArrayValueMap*, JSValue, bool shouldThrow);
  49     JSValue getNonSparseMode() const;
  50
  51     unsigned attributes;
  52 };
  53
  54 class SparseArrayValueMap final : public JSCell {
  55 public:
  56     typedef JSCell Base;
  57     static const unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
  58
  59 private:
  60     typedef HashMap<uint64_t, SparseArrayEntry, WTF::IntHash<uint64_t>, WTF::UnsignedWithZeroKeyHashTraits<uint64_t>> Map;
  61
  62     enum Flags {
  63         Normal = 0,
  64         SparseMode = 1,
  65         LengthIsReadOnly = 2,
  66     };
  67
  68     SparseArrayValueMap(VM&);
  69     ~SparseArrayValueMap();
  70
  71     void finishCreation(VM&);
  72
  73 public:
  74     DECLARE_EXPORT_INFO;
  75
  76     typedef Map::iterator iterator;
  77     typedef Map::const_iterator const_iterator;
  78     typedef Map::AddResult AddResult;
  79
  80     static SparseArrayValueMap* create(VM&);
  81
  82     static const bool needsDestruction = true;
  83     static void destroy(JSCell*);
  84
  85     static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype);
  86
  87     static void visitChildren(JSCell*, SlotVisitor&);
  88
  89     bool sparseMode()
  90     {
  91         return m_flags & SparseMode;
  92     }
  93
  94     void setSparseMode()
  95     {
  96         m_flags = static_cast<Flags>(m_flags | SparseMode);
  97     }
  98
  99     bool lengthIsReadOnly()
 100     {
 101         return m_flags & LengthIsReadOnly;
 102     }
 103
 104     void setLengthIsReadOnly()
 105     {
 106         m_flags = static_cast<Flags>(m_flags | LengthIsReadOnly);
 107     }
 108
 109     // These methods may mutate the contents of the map
 110     void putEntry(ExecState*, JSObject*, unsigned, JSValue, bool shouldThrow);
 111     bool putDirect(ExecState*, JSObject*, unsigned, JSValue, unsigned attributes, PutDirectIndexMode);
 112     AddResult add(JSObject*, unsigned);
 113     iterator find(unsigned i) { return m_map.find(i); }
 114     // This should ASSERT the remove is valid (check the result of the find).
 115     void remove(iterator it) { m_map.remove(it); }
 116     void remove(unsigned i) { m_map.remove(i); }
 117
 118     // These methods do not mutate the contents of the map.
 119     iterator notFound() { return m_map.end(); }
 120     bool isEmpty() const { return m_map.isEmpty(); }
 121     bool contains(unsigned i) const { return m_map.contains(i); }
 122     size_t size() const { return m_map.size(); }
 123     // Only allow const begin/end iteration.
 124     const_iterator begin() const { return m_map.begin(); }
 125     const_iterator end() const { return m_map.end(); }
 126
 127 private:
 128     Map m_map;
 129     Flags m_flags;
 130     size_t m_reportedCapacity;
 131 };
 132
 133 } // namespace JSC
 134
 135 #endif // SparseArrayValueMap_h
 136