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 #include <wtf/Platform.h>
  36
  37 namespace JSC {
  38
  39 class SparseArrayValueMap;
  40
  41 struct SparseArrayEntry : public WriteBarrier<Unknown> {
  42     typedef WriteBarrier<Unknown> Base;
  43
  44     SparseArrayEntry() : attributes(0) { }
  45
  46     JSValue get(ExecState*, JSObject*) const;
  47     void get(PropertySlot&) const;
  48     void get(PropertyDescriptor&) const;
  49     void put(ExecState*, JSValue thisValue, SparseArrayValueMap*, JSValue, bool shouldThrow);
  50     JSValue getNonSparseMode() const;
  51
  52     unsigned attributes;
  53 };
  54
  55 class SparseArrayValueMap : public JSCell {
  56 public:
  57     typedef JSCell Base;
  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     static const unsigned StructureFlags = OverridesVisitChildren | JSCell::StructureFlags;
  74
  75 public:
  76     static JS_EXPORTDATA const ClassInfo s_info;
  77
  78     typedef Map::iterator iterator;
  79     typedef Map::const_iterator const_iterator;
  80     typedef Map::AddResult AddResult;
  81
  82     static SparseArrayValueMap* create(VM&);
  83
  84     static const bool needsDestruction = true;
  85     static const bool hasImmortalStructure = true;
  86     static void destroy(JSCell*);
  87
  88     static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype);
  89
  90     static void visitChildren(JSCell*, SlotVisitor&);
  91
  92     bool sparseMode()
  93     {
  94         return m_flags & SparseMode;
  95     }
  96
  97     void setSparseMode()
  98     {
  99         m_flags = static_cast<Flags>(m_flags | SparseMode);
 100     }
 101
 102     bool lengthIsReadOnly()
 103     {
 104         return m_flags & LengthIsReadOnly;
 105     }
 106
 107     void setLengthIsReadOnly()
 108     {
 109         m_flags = static_cast<Flags>(m_flags | LengthIsReadOnly);
 110     }
 111
 112     // These methods may mutate the contents of the map
 113     void putEntry(ExecState*, JSObject*, unsigned, JSValue, bool shouldThrow);
 114     bool putDirect(ExecState*, JSObject*, unsigned, JSValue, unsigned attributes, PutDirectIndexMode);
 115     AddResult add(JSObject*, unsigned);
 116     iterator find(unsigned i) { return m_map.find(i); }
 117     // This should ASSERT the remove is valid (check the result of the find).
 118     void remove(iterator it) { m_map.remove(it); }
 119     void remove(unsigned i) { m_map.remove(i); }
 120
 121     // These methods do not mutate the contents of the map.
 122     iterator notFound() { return m_map.end(); }
 123     bool isEmpty() const { return m_map.isEmpty(); }
 124     bool contains(unsigned i) const { return m_map.contains(i); }
 125     size_t size() const { return m_map.size(); }
 126     // Only allow const begin/end iteration.
 127     const_iterator begin() const { return m_map.begin(); }
 128     const_iterator end() const { return m_map.end(); }
 129
 130 private:
 131     Map m_map;
 132     Flags m_flags;
 133     size_t m_reportedCapacity;
 134 };
 135
 136 } // namespace JSC
 137
 138 #endif // SparseArrayValueMap_h
 139