1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/public/Id.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,185 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef js_Id_h
1.11 +#define js_Id_h
1.12 +
1.13 +// A jsid is an identifier for a property or method of an object which is
1.14 +// either a 31-bit signed integer, interned string or object.
1.15 +//
1.16 +// Also, there is an additional jsid value, JSID_VOID, which does not occur in
1.17 +// JS scripts but may be used to indicate the absence of a valid jsid. A void
1.18 +// jsid is not a valid id and only arises as an exceptional API return value,
1.19 +// such as in JS_NextProperty. Embeddings must not pass JSID_VOID into JSAPI
1.20 +// entry points expecting a jsid and do not need to handle JSID_VOID in hooks
1.21 +// receiving a jsid except when explicitly noted in the API contract.
1.22 +//
1.23 +// A jsid is not implicitly convertible to or from a jsval; JS_ValueToId or
1.24 +// JS_IdToValue must be used instead.
1.25 +
1.26 +#include "mozilla/NullPtr.h"
1.27 +
1.28 +#include "jstypes.h"
1.29 +
1.30 +#include "js/HeapAPI.h"
1.31 +#include "js/RootingAPI.h"
1.32 +#include "js/TypeDecls.h"
1.33 +#include "js/Utility.h"
1.34 +
1.35 +struct jsid
1.36 +{
1.37 + size_t asBits;
1.38 + bool operator==(jsid rhs) const { return asBits == rhs.asBits; }
1.39 + bool operator!=(jsid rhs) const { return asBits != rhs.asBits; }
1.40 +};
1.41 +#define JSID_BITS(id) (id.asBits)
1.42 +
1.43 +#define JSID_TYPE_STRING 0x0
1.44 +#define JSID_TYPE_INT 0x1
1.45 +#define JSID_TYPE_VOID 0x2
1.46 +#define JSID_TYPE_OBJECT 0x4
1.47 +#define JSID_TYPE_MASK 0x7
1.48 +
1.49 +// Avoid using canonical 'id' for jsid parameters since this is a magic word in
1.50 +// Objective-C++ which, apparently, wants to be able to #include jsapi.h.
1.51 +#define id iden
1.52 +
1.53 +static MOZ_ALWAYS_INLINE bool
1.54 +JSID_IS_STRING(jsid id)
1.55 +{
1.56 + return (JSID_BITS(id) & JSID_TYPE_MASK) == 0;
1.57 +}
1.58 +
1.59 +static MOZ_ALWAYS_INLINE JSString *
1.60 +JSID_TO_STRING(jsid id)
1.61 +{
1.62 + MOZ_ASSERT(JSID_IS_STRING(id));
1.63 + return (JSString *)JSID_BITS(id);
1.64 +}
1.65 +
1.66 +static MOZ_ALWAYS_INLINE bool
1.67 +JSID_IS_ZERO(jsid id)
1.68 +{
1.69 + return JSID_BITS(id) == 0;
1.70 +}
1.71 +
1.72 +static MOZ_ALWAYS_INLINE bool
1.73 +JSID_IS_INT(jsid id)
1.74 +{
1.75 + return !!(JSID_BITS(id) & JSID_TYPE_INT);
1.76 +}
1.77 +
1.78 +static MOZ_ALWAYS_INLINE int32_t
1.79 +JSID_TO_INT(jsid id)
1.80 +{
1.81 + MOZ_ASSERT(JSID_IS_INT(id));
1.82 + return ((uint32_t)JSID_BITS(id)) >> 1;
1.83 +}
1.84 +
1.85 +#define JSID_INT_MIN 0
1.86 +#define JSID_INT_MAX INT32_MAX
1.87 +
1.88 +static MOZ_ALWAYS_INLINE bool
1.89 +INT_FITS_IN_JSID(int32_t i)
1.90 +{
1.91 + return i >= 0;
1.92 +}
1.93 +
1.94 +static MOZ_ALWAYS_INLINE jsid
1.95 +INT_TO_JSID(int32_t i)
1.96 +{
1.97 + jsid id;
1.98 + MOZ_ASSERT(INT_FITS_IN_JSID(i));
1.99 + JSID_BITS(id) = ((i << 1) | JSID_TYPE_INT);
1.100 + return id;
1.101 +}
1.102 +
1.103 +static MOZ_ALWAYS_INLINE bool
1.104 +JSID_IS_OBJECT(jsid id)
1.105 +{
1.106 + return (JSID_BITS(id) & JSID_TYPE_MASK) == JSID_TYPE_OBJECT &&
1.107 + (size_t)JSID_BITS(id) != JSID_TYPE_OBJECT;
1.108 +}
1.109 +
1.110 +static MOZ_ALWAYS_INLINE JSObject *
1.111 +JSID_TO_OBJECT(jsid id)
1.112 +{
1.113 + MOZ_ASSERT(JSID_IS_OBJECT(id));
1.114 + return (JSObject *)(JSID_BITS(id) & ~(size_t)JSID_TYPE_MASK);
1.115 +}
1.116 +
1.117 +static MOZ_ALWAYS_INLINE jsid
1.118 +OBJECT_TO_JSID(JSObject *obj)
1.119 +{
1.120 + jsid id;
1.121 + MOZ_ASSERT(obj != nullptr);
1.122 + MOZ_ASSERT(((size_t)obj & JSID_TYPE_MASK) == 0);
1.123 + JS_ASSERT(!js::gc::IsInsideNursery(js::gc::GetGCThingRuntime(obj), obj));
1.124 + JSID_BITS(id) = ((size_t)obj | JSID_TYPE_OBJECT);
1.125 + return id;
1.126 +}
1.127 +
1.128 +static MOZ_ALWAYS_INLINE bool
1.129 +JSID_IS_GCTHING(jsid id)
1.130 +{
1.131 + return JSID_IS_STRING(id) || JSID_IS_OBJECT(id);
1.132 +}
1.133 +
1.134 +static MOZ_ALWAYS_INLINE void *
1.135 +JSID_TO_GCTHING(jsid id)
1.136 +{
1.137 + return (void *)(JSID_BITS(id) & ~(size_t)JSID_TYPE_MASK);
1.138 +}
1.139 +
1.140 +static MOZ_ALWAYS_INLINE bool
1.141 +JSID_IS_VOID(const jsid id)
1.142 +{
1.143 + MOZ_ASSERT_IF(((size_t)JSID_BITS(id) & JSID_TYPE_MASK) == JSID_TYPE_VOID,
1.144 + JSID_BITS(id) == JSID_TYPE_VOID);
1.145 + return ((size_t)JSID_BITS(id) == JSID_TYPE_VOID);
1.146 +}
1.147 +
1.148 +static MOZ_ALWAYS_INLINE bool
1.149 +JSID_IS_EMPTY(const jsid id)
1.150 +{
1.151 + return ((size_t)JSID_BITS(id) == JSID_TYPE_OBJECT);
1.152 +}
1.153 +
1.154 +#undef id
1.155 +
1.156 +extern JS_PUBLIC_DATA(const jsid) JSID_VOID;
1.157 +extern JS_PUBLIC_DATA(const jsid) JSID_EMPTY;
1.158 +
1.159 +extern JS_PUBLIC_DATA(const JS::HandleId) JSID_VOIDHANDLE;
1.160 +extern JS_PUBLIC_DATA(const JS::HandleId) JSID_EMPTYHANDLE;
1.161 +
1.162 +namespace js {
1.163 +
1.164 +inline bool
1.165 +IsPoisonedId(jsid iden)
1.166 +{
1.167 + if (JSID_IS_STRING(iden))
1.168 + return JS::IsPoisonedPtr(JSID_TO_STRING(iden));
1.169 + if (JSID_IS_OBJECT(iden))
1.170 + return JS::IsPoisonedPtr(JSID_TO_OBJECT(iden));
1.171 + return false;
1.172 +}
1.173 +
1.174 +template <> struct GCMethods<jsid>
1.175 +{
1.176 + static jsid initial() { return JSID_VOID; }
1.177 + static ThingRootKind kind() { return THING_ROOT_ID; }
1.178 + static bool poisoned(jsid id) { return IsPoisonedId(id); }
1.179 + static bool needsPostBarrier(jsid id) { return false; }
1.180 +#ifdef JSGC_GENERATIONAL
1.181 + static void postBarrier(jsid *idp) {}
1.182 + static void relocate(jsid *idp) {}
1.183 +#endif
1.184 +};
1.185 +
1.186 +}
1.187 +
1.188 +#endif /* js_Id_h */
