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: #ifndef js_Id_h
michael@0: #define js_Id_h
michael@0: 
michael@0: // A jsid is an identifier for a property or method of an object which is
michael@0: // either a 31-bit signed integer, interned string or object.
michael@0: //
michael@0: // Also, there is an additional jsid value, JSID_VOID, which does not occur in
michael@0: // JS scripts but may be used to indicate the absence of a valid jsid.  A void
michael@0: // jsid is not a valid id and only arises as an exceptional API return value,
michael@0: // such as in JS_NextProperty. Embeddings must not pass JSID_VOID into JSAPI
michael@0: // entry points expecting a jsid and do not need to handle JSID_VOID in hooks
michael@0: // receiving a jsid except when explicitly noted in the API contract.
michael@0: //
michael@0: // A jsid is not implicitly convertible to or from a jsval; JS_ValueToId or
michael@0: // JS_IdToValue must be used instead.
michael@0: 
michael@0: #include "mozilla/NullPtr.h"
michael@0: 
michael@0: #include "jstypes.h"
michael@0: 
michael@0: #include "js/HeapAPI.h"
michael@0: #include "js/RootingAPI.h"
michael@0: #include "js/TypeDecls.h"
michael@0: #include "js/Utility.h"
michael@0: 
michael@0: struct jsid
michael@0: {
michael@0:     size_t asBits;
michael@0:     bool operator==(jsid rhs) const { return asBits == rhs.asBits; }
michael@0:     bool operator!=(jsid rhs) const { return asBits != rhs.asBits; }
michael@0: };
michael@0: #define JSID_BITS(id) (id.asBits)
michael@0: 
michael@0: #define JSID_TYPE_STRING                 0x0
michael@0: #define JSID_TYPE_INT                    0x1
michael@0: #define JSID_TYPE_VOID                   0x2
michael@0: #define JSID_TYPE_OBJECT                 0x4
michael@0: #define JSID_TYPE_MASK                   0x7
michael@0: 
michael@0: // Avoid using canonical 'id' for jsid parameters since this is a magic word in
michael@0: // Objective-C++ which, apparently, wants to be able to #include jsapi.h.
michael@0: #define id iden
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: JSID_IS_STRING(jsid id)
michael@0: {
michael@0:     return (JSID_BITS(id) & JSID_TYPE_MASK) == 0;
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE JSString *
michael@0: JSID_TO_STRING(jsid id)
michael@0: {
michael@0:     MOZ_ASSERT(JSID_IS_STRING(id));
michael@0:     return (JSString *)JSID_BITS(id);
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: JSID_IS_ZERO(jsid id)
michael@0: {
michael@0:     return JSID_BITS(id) == 0;
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: JSID_IS_INT(jsid id)
michael@0: {
michael@0:     return !!(JSID_BITS(id) & JSID_TYPE_INT);
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE int32_t
michael@0: JSID_TO_INT(jsid id)
michael@0: {
michael@0:     MOZ_ASSERT(JSID_IS_INT(id));
michael@0:     return ((uint32_t)JSID_BITS(id)) >> 1;
michael@0: }
michael@0: 
michael@0: #define JSID_INT_MIN  0
michael@0: #define JSID_INT_MAX  INT32_MAX
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: INT_FITS_IN_JSID(int32_t i)
michael@0: {
michael@0:     return i >= 0;
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE jsid
michael@0: INT_TO_JSID(int32_t i)
michael@0: {
michael@0:     jsid id;
michael@0:     MOZ_ASSERT(INT_FITS_IN_JSID(i));
michael@0:     JSID_BITS(id) = ((i << 1) | JSID_TYPE_INT);
michael@0:     return id;
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: JSID_IS_OBJECT(jsid id)
michael@0: {
michael@0:     return (JSID_BITS(id) & JSID_TYPE_MASK) == JSID_TYPE_OBJECT &&
michael@0:            (size_t)JSID_BITS(id) != JSID_TYPE_OBJECT;
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE JSObject *
michael@0: JSID_TO_OBJECT(jsid id)
michael@0: {
michael@0:     MOZ_ASSERT(JSID_IS_OBJECT(id));
michael@0:     return (JSObject *)(JSID_BITS(id) & ~(size_t)JSID_TYPE_MASK);
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE jsid
michael@0: OBJECT_TO_JSID(JSObject *obj)
michael@0: {
michael@0:     jsid id;
michael@0:     MOZ_ASSERT(obj != nullptr);
michael@0:     MOZ_ASSERT(((size_t)obj & JSID_TYPE_MASK) == 0);
michael@0:     JS_ASSERT(!js::gc::IsInsideNursery(js::gc::GetGCThingRuntime(obj), obj));
michael@0:     JSID_BITS(id) = ((size_t)obj | JSID_TYPE_OBJECT);
michael@0:     return id;
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: JSID_IS_GCTHING(jsid id)
michael@0: {
michael@0:     return JSID_IS_STRING(id) || JSID_IS_OBJECT(id);
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE void *
michael@0: JSID_TO_GCTHING(jsid id)
michael@0: {
michael@0:     return (void *)(JSID_BITS(id) & ~(size_t)JSID_TYPE_MASK);
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: JSID_IS_VOID(const jsid id)
michael@0: {
michael@0:     MOZ_ASSERT_IF(((size_t)JSID_BITS(id) & JSID_TYPE_MASK) == JSID_TYPE_VOID,
michael@0:                  JSID_BITS(id) == JSID_TYPE_VOID);
michael@0:     return ((size_t)JSID_BITS(id) == JSID_TYPE_VOID);
michael@0: }
michael@0: 
michael@0: static MOZ_ALWAYS_INLINE bool
michael@0: JSID_IS_EMPTY(const jsid id)
michael@0: {
michael@0:     return ((size_t)JSID_BITS(id) == JSID_TYPE_OBJECT);
michael@0: }
michael@0: 
michael@0: #undef id
michael@0: 
michael@0: extern JS_PUBLIC_DATA(const jsid) JSID_VOID;
michael@0: extern JS_PUBLIC_DATA(const jsid) JSID_EMPTY;
michael@0: 
michael@0: extern JS_PUBLIC_DATA(const JS::HandleId) JSID_VOIDHANDLE;
michael@0: extern JS_PUBLIC_DATA(const JS::HandleId) JSID_EMPTYHANDLE;
michael@0: 
michael@0: namespace js {
michael@0: 
michael@0: inline bool
michael@0: IsPoisonedId(jsid iden)
michael@0: {
michael@0:     if (JSID_IS_STRING(iden))
michael@0:         return JS::IsPoisonedPtr(JSID_TO_STRING(iden));
michael@0:     if (JSID_IS_OBJECT(iden))
michael@0:         return JS::IsPoisonedPtr(JSID_TO_OBJECT(iden));
michael@0:     return false;
michael@0: }
michael@0: 
michael@0: template <> struct GCMethods<jsid>
michael@0: {
michael@0:     static jsid initial() { return JSID_VOID; }
michael@0:     static ThingRootKind kind() { return THING_ROOT_ID; }
michael@0:     static bool poisoned(jsid id) { return IsPoisonedId(id); }
michael@0:     static bool needsPostBarrier(jsid id) { return false; }
michael@0: #ifdef JSGC_GENERATIONAL
michael@0:     static void postBarrier(jsid *idp) {}
michael@0:     static void relocate(jsid *idp) {}
michael@0: #endif
michael@0: };
michael@0: 
michael@0: }
michael@0: 
michael@0: #endif /* js_Id_h */