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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* 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/. */
#ifndef jspropertytree_h
#define jspropertytree_h
#include "jsalloc.h"
#include "jspubtd.h"
#include "js/HashTable.h"
namespace js {
class Shape;
struct StackShape;
struct ShapeHasher : public DefaultHasher<Shape*> {
typedef Shape* Key;
typedef StackShape Lookup;
static inline HashNumber hash(const Lookup& l);
static inline bool match(Key k, const Lookup& l);
};
typedef HashSet<Shape*, ShapeHasher, SystemAllocPolicy> KidsHash;
class KidsPointer {
private:
enum {
SHAPE = 0,
HASH = 1,
TAG = 1
};
uintptr_t w;
public:
bool isNull() const { return !w; }
void setNull() { w = 0; }
bool isShape() const { return (w & TAG) == SHAPE && !isNull(); }
Shape* toShape() const {
MOZ_ASSERT(isShape());
return reinterpret_cast<Shape*>(w & ~uintptr_t(TAG));
}
void setShape(Shape* shape) {
MOZ_ASSERT(shape);
MOZ_ASSERT((reinterpret_cast<uintptr_t>(static_cast<Shape*>(shape)) & TAG) == 0);
w = reinterpret_cast<uintptr_t>(static_cast<Shape*>(shape)) | SHAPE;
}
bool isHash() const { return (w & TAG) == HASH; }
KidsHash* toHash() const {
MOZ_ASSERT(isHash());
return reinterpret_cast<KidsHash*>(w & ~uintptr_t(TAG));
}
void setHash(KidsHash* hash) {
MOZ_ASSERT(hash);
MOZ_ASSERT((reinterpret_cast<uintptr_t>(hash) & TAG) == 0);
w = reinterpret_cast<uintptr_t>(hash) | HASH;
}
#ifdef DEBUG
void checkConsistency(Shape* aKid) const;
#endif
};
class PropertyTree
{
friend class ::JSFunction;
#ifdef DEBUG
JS::Zone* zone_;
#endif
bool insertChild(ExclusiveContext* cx, Shape* parent, Shape* child);
PropertyTree();
public:
/*
* Use a lower limit for objects that are accessed using SETELEM (o[x] = y).
* These objects are likely used as hashmaps and dictionary mode is more
* efficient in this case.
*/
enum {
MAX_HEIGHT = 512,
MAX_HEIGHT_WITH_ELEMENTS_ACCESS = 128
};
explicit PropertyTree(JS::Zone* zone)
#ifdef DEBUG
: zone_(zone)
#endif
{
}
Shape* getChild(ExclusiveContext* cx, Shape* parent, JS::Handle<StackShape> child);
};
} /* namespace js */
#endif /* jspropertytree_h */
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