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comparison: js/public/PropertyKey.h
js/public/PropertyKey.h
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| 1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- | |
| 2 * vim: set ts=8 sts=4 et sw=4 tw=99: | |
| 3 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 4 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 6 | |
| 7 /* JS::PropertyKey implementation. */ | |
| 8 | |
| 9 #ifndef js_PropertyKey_h | |
| 10 #define js_PropertyKey_h | |
| 11 | |
| 12 #include "js/TypeDecls.h" | |
| 13 #include "js/Value.h" | |
| 14 | |
| 15 namespace JS { | |
| 16 | |
| 17 class PropertyKey; | |
| 18 | |
| 19 namespace detail { | |
| 20 | |
| 21 extern JS_PUBLIC_API(bool) | |
| 22 ToPropertyKeySlow(JSContext *cx, HandleValue v, PropertyKey *key); | |
| 23 | |
| 24 } // namespace detail | |
| 25 | |
| 26 /* | |
| 27 * A PropertyKey is a key used to access some property on an object. It is a | |
| 28 * natural way to represent a property accessed using a JavaScript value. | |
| 29 * | |
| 30 * PropertyKey can represent indexes, named properties, and ES6 symbols. The | |
| 31 * latter aren't implemented in SpiderMonkey yet, but PropertyKey carves out | |
| 32 * space for them. | |
| 33 */ | |
| 34 class PropertyKey | |
| 35 { | |
| 36 Value v; | |
| 37 friend JS_PUBLIC_API(bool) detail::ToPropertyKeySlow(JSContext *cx, HandleValue v, PropertyKey *key); | |
| 38 | |
| 39 public: | |
| 40 explicit PropertyKey(uint32_t index) : v(PrivateUint32Value(index)) {} | |
| 41 | |
| 42 /* | |
| 43 * An index is a string property name whose characters exactly spell out an | |
| 44 * unsigned 32-bit integer in decimal: "0", "1", "2", ...., "4294967294", | |
| 45 * "4294967295". | |
| 46 */ | |
| 47 bool isIndex(uint32_t *index) { | |
| 48 // The implementation here assumes that private uint32_t are stored | |
| 49 // using the int32_t representation. This is purely an implementation | |
| 50 // detail: embedders must not rely upon this! | |
| 51 if (!v.isInt32()) | |
| 52 return false; | |
| 53 *index = v.toPrivateUint32(); | |
| 54 return true; | |
| 55 } | |
| 56 | |
| 57 /* | |
| 58 * A name is a string property name which is *not* an index. Note that by | |
| 59 * the ECMAScript language grammar, any dotted property access |obj.prop| | |
| 60 * will access a named property. | |
| 61 */ | |
| 62 bool isName(JSString **str) { | |
| 63 uint32_t dummy; | |
| 64 if (isIndex(&dummy)) | |
| 65 return false; | |
| 66 *str = v.toString(); | |
| 67 return true; | |
| 68 } | |
| 69 | |
| 70 /* | |
| 71 * A symbol is a property name that's a Symbol, a particular kind of object | |
| 72 * in ES6. It is the only kind of property name that's not a string. | |
| 73 * | |
| 74 * SpiderMonkey doesn't yet implement symbols, but we're carving out API | |
| 75 * space for them in advance. | |
| 76 */ | |
| 77 bool isSymbol() { | |
| 78 return false; | |
| 79 } | |
| 80 }; | |
| 81 | |
| 82 inline bool | |
| 83 ToPropertyKey(JSContext *cx, HandleValue v, PropertyKey *key) | |
| 84 { | |
| 85 if (v.isInt32() && v.toInt32() >= 0) { | |
| 86 *key = PropertyKey(uint32_t(v.toInt32())); | |
| 87 return true; | |
| 88 } | |
| 89 | |
| 90 return detail::ToPropertyKeySlow(cx, v, key); | |
| 91 } | |
| 92 | |
| 93 } // namespace JS | |
| 94 | |
| 95 #endif /* js_PropertyKey_h */ |
