From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- js/src/jspropertytree.h | 106 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 js/src/jspropertytree.h (limited to 'js/src/jspropertytree.h') diff --git a/js/src/jspropertytree.h b/js/src/jspropertytree.h new file mode 100644 index 000000000..b2544d496 --- /dev/null +++ b/js/src/jspropertytree.h @@ -0,0 +1,106 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * vim: set ts=8 sts=4 et sw=4 tw=99: + * 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 { + typedef Shape* Key; + typedef StackShape Lookup; + + static inline HashNumber hash(const Lookup& l); + static inline bool match(Key k, const Lookup& l); +}; + +typedef HashSet 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(w & ~uintptr_t(TAG)); + } + void setShape(Shape* shape) { + MOZ_ASSERT(shape); + MOZ_ASSERT((reinterpret_cast(static_cast(shape)) & TAG) == 0); + w = reinterpret_cast(static_cast(shape)) | SHAPE; + } + + bool isHash() const { return (w & TAG) == HASH; } + KidsHash* toHash() const { + MOZ_ASSERT(isHash()); + return reinterpret_cast(w & ~uintptr_t(TAG)); + } + void setHash(KidsHash* hash) { + MOZ_ASSERT(hash); + MOZ_ASSERT((reinterpret_cast(hash) & TAG) == 0); + w = reinterpret_cast(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 child); +}; + +} /* namespace js */ + +#endif /* jspropertytree_h */ -- cgit v1.2.3