зеркало из https://github.com/mozilla/gecko-dev.git
97 строки
2.7 KiB
C++
97 строки
2.7 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* vim: set ts=8 sts=4 et sw=4 tw=99:
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* JS::PropertyKey implementation. */
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#ifndef js_PropertyKey_h
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#define js_PropertyKey_h
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#include "js/Value.h"
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struct JSContext;
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namespace JS {
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class PropertyKey;
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namespace detail {
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extern JS_PUBLIC_API(bool)
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ToPropertyKeySlow(JSContext *cx, HandleValue v, PropertyKey *key);
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} // namespace detail
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/*
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* A PropertyKey is a key used to access some property on an object. It is a
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* natural way to represent a property accessed using a JavaScript value.
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*
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* PropertyKey can represent indexes, named properties, and ES6 symbols. The
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* latter aren't implemented in SpiderMonkey yet, but PropertyKey carves out
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* space for them.
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*/
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class PropertyKey
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{
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Value v;
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friend JS_PUBLIC_API(bool) detail::ToPropertyKeySlow(JSContext *cx, HandleValue v, PropertyKey *key);
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public:
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explicit PropertyKey(uint32_t index) : v(PrivateUint32Value(index)) {}
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/*
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* An index is a string property name whose characters exactly spell out an
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* unsigned 32-bit integer in decimal: "0", "1", "2", ...., "4294967294",
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* "4294967295".
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*/
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bool isIndex(uint32_t *index) {
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// The implementation here assumes that private uint32_t are stored
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// using the int32_t representation. This is purely an implementation
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// detail: embedders must not rely upon this!
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if (!v.isInt32())
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return false;
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*index = v.toPrivateUint32();
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return true;
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}
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/*
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* A name is a string property name which is *not* an index. Note that by
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* the ECMAScript language grammar, any dotted property access |obj.prop|
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* will access a named property.
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*/
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bool isName(JSString **str) {
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uint32_t dummy;
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if (isIndex(&dummy))
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return false;
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*str = v.toString();
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return true;
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}
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/*
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* A symbol is a property name that's a Symbol, a particular kind of object
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* in ES6. It is the only kind of property name that's not a string.
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*
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* SpiderMonkey doesn't yet implement symbols, but we're carving out API
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* space for them in advance.
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*/
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bool isSymbol() {
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return false;
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}
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};
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inline bool
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ToPropertyKey(JSContext *cx, HandleValue v, PropertyKey *key)
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{
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if (v.isInt32() && v.toInt32() >= 0) {
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*key = PropertyKey(uint32_t(v.toInt32()));
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return true;
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}
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return detail::ToPropertyKeySlow(cx, v, key);
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}
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} // namespace JS
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#endif /* js_PropertyKey_h */
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