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