/usr/include/js-17.0/jsatom.h is in libmozjs-17.0-dev 17.0.0-1ubuntu1.
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*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef jsatom_h___
#define jsatom_h___
#include <stddef.h>
#include "jsversion.h"
#include "jsalloc.h"
#include "jsapi.h"
#include "jsprvtd.h"
#include "jspubtd.h"
#include "jslock.h"
#include "gc/Barrier.h"
#include "js/HashTable.h"
#include "mozilla/HashFunctions.h"
struct JSIdArray {
int length;
js::HeapId vector[1]; /* actually, length jsid words */
};
/* Engine-internal extensions of jsid */
static JS_ALWAYS_INLINE jsid
JSID_FROM_BITS(size_t bits)
{
jsid id;
JSID_BITS(id) = bits;
return id;
}
/*
* Must not be used on atoms that are representable as integer jsids.
* Prefer NameToId or AtomToId over this function:
*
* A PropertyName is an atom that does not contain an integer in the range
* [0, UINT32_MAX]. However, jsid can only hold an integer in the range
* [0, JSID_INT_MAX] (where JSID_INT_MAX == 2^31-1). Thus, for the range of
* integers (JSID_INT_MAX, UINT32_MAX], to represent as a jsid 'id', it must be
* the case JSID_IS_ATOM(id) and !JSID_TO_ATOM(id)->isPropertyName(). In most
* cases when creating a jsid, code does not have to care about this corner
* case because:
*
* - When given an arbitrary JSAtom*, AtomToId must be used, which checks for
* integer atoms representable as integer jsids, and does this conversion.
*
* - When given a PropertyName*, NameToId can be used which which does not need
* to do any dynamic checks.
*
* Thus, it is only the rare third case which needs this function, which
* handles any JSAtom* that is known not to be representable with an int jsid.
*/
static JS_ALWAYS_INLINE jsid
NON_INTEGER_ATOM_TO_JSID(JSAtom *atom)
{
JS_ASSERT(((size_t)atom & 0x7) == 0);
jsid id = JSID_FROM_BITS((size_t)atom);
JS_ASSERT(id == INTERNED_STRING_TO_JSID(NULL, (JSString*)atom));
return id;
}
/* All strings stored in jsids are atomized, but are not necessarily property names. */
static JS_ALWAYS_INLINE JSBool
JSID_IS_ATOM(jsid id)
{
return JSID_IS_STRING(id);
}
static JS_ALWAYS_INLINE JSBool
JSID_IS_ATOM(jsid id, JSAtom *atom)
{
return id == JSID_FROM_BITS((size_t)atom);
}
static JS_ALWAYS_INLINE JSAtom *
JSID_TO_ATOM(jsid id)
{
return (JSAtom *)JSID_TO_STRING(id);
}
JS_STATIC_ASSERT(sizeof(js::HashNumber) == 4);
JS_STATIC_ASSERT(sizeof(jsid) == JS_BYTES_PER_WORD);
namespace js {
static JS_ALWAYS_INLINE js::HashNumber
HashId(jsid id)
{
return HashGeneric(JSID_BITS(id));
}
static JS_ALWAYS_INLINE Value
IdToValue(jsid id)
{
if (JSID_IS_STRING(id))
return StringValue(JSID_TO_STRING(id));
if (JS_LIKELY(JSID_IS_INT(id)))
return Int32Value(JSID_TO_INT(id));
if (JS_LIKELY(JSID_IS_OBJECT(id)))
return ObjectValue(*JSID_TO_OBJECT(id));
JS_ASSERT(JSID_IS_DEFAULT_XML_NAMESPACE(id) || JSID_IS_VOID(id));
return UndefinedValue();
}
static JS_ALWAYS_INLINE jsval
IdToJsval(jsid id)
{
return IdToValue(id);
}
template<>
struct DefaultHasher<jsid>
{
typedef jsid Lookup;
static HashNumber hash(const Lookup &l) {
return HashNumber(JSID_BITS(l));
}
static bool match(const jsid &id, const Lookup &l) {
return id == l;
}
};
}
/*
* Return a printable, lossless char[] representation of a string-type atom.
* The lifetime of the result matches the lifetime of bytes.
*/
extern const char *
js_AtomToPrintableString(JSContext *cx, JSAtom *atom, JSAutoByteString *bytes);
namespace js {
/* Compute a hash function from chars/length. */
inline uint32_t
HashChars(const jschar *chars, size_t length)
{
uint32_t h = 0;
for (; length; chars++, length--)
h = JS_ROTATE_LEFT32(h, 4) ^ *chars;
return h;
}
class AtomStateEntry
{
uintptr_t bits;
static const uintptr_t NO_TAG_MASK = uintptr_t(-1) - 1;
public:
AtomStateEntry() : bits(0) {}
AtomStateEntry(const AtomStateEntry &other) : bits(other.bits) {}
AtomStateEntry(JSAtom *ptr, bool tagged)
: bits(uintptr_t(ptr) | uintptr_t(tagged))
{
JS_ASSERT((uintptr_t(ptr) & 0x1) == 0);
}
bool isTagged() const {
return bits & 0x1;
}
/*
* Non-branching code sequence. Note that the const_cast is safe because
* the hash function doesn't consider the tag to be a portion of the key.
*/
void setTagged(bool enabled) const {
const_cast<AtomStateEntry *>(this)->bits |= uintptr_t(enabled);
}
JSAtom *asPtr() const;
};
struct AtomHasher
{
struct Lookup
{
const jschar *chars;
size_t length;
const JSAtom *atom; /* Optional. */
Lookup(const jschar *chars, size_t length) : chars(chars), length(length), atom(NULL) {}
inline Lookup(const JSAtom *atom);
};
static HashNumber hash(const Lookup &l) { return HashChars(l.chars, l.length); }
static inline bool match(const AtomStateEntry &entry, const Lookup &lookup);
};
typedef HashSet<AtomStateEntry, AtomHasher, SystemAllocPolicy> AtomSet;
/*
* On encodings:
*
* - Some string functions have an optional FlationCoding argument that allow
* the caller to force CESU-8 encoding handling.
* - Functions that don't take a FlationCoding base their NormalEncoding
* behavior on the js_CStringsAreUTF8 value. NormalEncoding is either raw
* (simple zero-extension) or UTF-8 depending on js_CStringsAreUTF8.
* - Functions that explicitly state their encoding do not use the
* js_CStringsAreUTF8 value.
*
* CESU-8 (Compatibility Encoding Scheme for UTF-16: 8-bit) is a variant of
* UTF-8 that allows us to store any wide character string as a narrow
* character string. For strings containing mostly ascii, it saves space.
* http://www.unicode.org/reports/tr26/
*/
enum FlationCoding
{
NormalEncoding,
CESU8Encoding
};
class PropertyName;
} /* namespace js */
struct JSAtomState
{
js::AtomSet atoms;
/*
* From this point until the end of struct definition the struct must
* contain only js::PropertyName fields. We use this to access the storage
* occupied by the common atoms in js_FinishCommonAtoms.
*
* js_common_atom_names defined in jsatom.cpp contains C strings for atoms
* in the order of atom fields here. Therefore you must update that array
* if you change member order here.
*/
/* The rt->emptyString atom, see jsstr.c's js_InitRuntimeStringState. */
js::PropertyName *emptyAtom;
/*
* Literal value and type names.
* NB: booleanAtoms must come right before typeAtoms!
*/
js::PropertyName *booleanAtoms[2];
js::PropertyName *typeAtoms[JSTYPE_LIMIT];
js::PropertyName *nullAtom;
/* Standard class constructor or prototype names. */
js::PropertyName *classAtoms[JSProto_LIMIT];
/* Various built-in or commonly-used atoms, pinned on first context. */
#define DEFINE_ATOM(id, text) js::PropertyName *id##Atom;
#define DEFINE_PROTOTYPE_ATOM(id) js::PropertyName *id##Atom;
#define DEFINE_KEYWORD_ATOM(id) js::PropertyName *id##Atom;
#include "jsatom.tbl"
#undef DEFINE_ATOM
#undef DEFINE_PROTOTYPE_ATOM
#undef DEFINE_KEYWORD_ATOM
static const size_t commonAtomsOffset;
void junkAtoms() {
#ifdef DEBUG
memset(commonAtomsStart(), JS_FREE_PATTERN, sizeof(*this) - commonAtomsOffset);
#endif
}
JSAtom **commonAtomsStart() {
return reinterpret_cast<JSAtom **>(&emptyAtom);
}
void checkStaticInvariants();
};
extern bool
AtomIsInterned(JSContext *cx, JSAtom *atom);
#define ATOM(name) js::HandlePropertyName::fromMarkedLocation(&cx->runtime->atomState.name##Atom)
#define COMMON_ATOM_INDEX(name) \
((offsetof(JSAtomState, name##Atom) - JSAtomState::commonAtomsOffset) \
/ sizeof(JSAtom*))
#define COMMON_TYPE_ATOM_INDEX(type) \
((offsetof(JSAtomState, typeAtoms[type]) - JSAtomState::commonAtomsOffset)\
/ sizeof(JSAtom*))
#define NAME_OFFSET(name) offsetof(JSAtomState, name##Atom)
#define OFFSET_TO_NAME(rt,off) (*(js::PropertyName **)((char*)&(rt)->atomState + (off)))
#define CLASS_NAME_OFFSET(name) offsetof(JSAtomState, classAtoms[JSProto_##name])
#define CLASS_NAME(cx,name) ((cx)->runtime->atomState.classAtoms[JSProto_##name])
extern const char *const js_common_atom_names[];
extern const size_t js_common_atom_count;
/*
* Macros to access C strings for JSType and boolean literals.
*/
#define JS_BOOLEAN_STR(type) (js_common_atom_names[1 + (type)])
#define JS_TYPE_STR(type) (js_common_atom_names[1 + 2 + (type)])
/* Type names. */
extern const char js_object_str[];
extern const char js_undefined_str[];
/* Well-known predefined C strings. */
#define JS_PROTO(name,code,init) extern const char js_##name##_str[];
#include "jsproto.tbl"
#undef JS_PROTO
#define DEFINE_ATOM(id, text) extern const char js_##id##_str[];
#define DEFINE_PROTOTYPE_ATOM(id)
#define DEFINE_KEYWORD_ATOM(id)
#include "jsatom.tbl"
#undef DEFINE_ATOM
#undef DEFINE_PROTOTYPE_ATOM
#undef DEFINE_KEYWORD_ATOM
#if JS_HAS_GENERATORS
extern const char js_close_str[];
extern const char js_send_str[];
#endif
/* Constant strings that are not atomized. */
extern const char js_getter_str[];
extern const char js_setter_str[];
namespace js {
/*
* Initialize atom state. Return true on success, false on failure to allocate
* memory. The caller must zero rt->atomState before calling this function and
* only call it after js_InitGC successfully returns.
*/
extern JSBool
InitAtomState(JSRuntime *rt);
/*
* Free and clear atom state including any interned string atoms. This
* function must be called before js_FinishGC.
*/
extern void
FinishAtomState(JSRuntime *rt);
/*
* Atom tracing and garbage collection hooks.
*/
extern void
MarkAtomState(JSTracer *trc);
extern void
SweepAtomState(JSRuntime *rt);
extern bool
InitCommonAtoms(JSContext *cx);
extern void
FinishCommonAtoms(JSRuntime *rt);
/* N.B. must correspond to boolean tagging behavior. */
enum InternBehavior
{
DoNotInternAtom = false,
InternAtom = true
};
extern JSAtom *
Atomize(JSContext *cx, const char *bytes, size_t length,
js::InternBehavior ib = js::DoNotInternAtom,
js::FlationCoding fc = js::NormalEncoding);
extern JSAtom *
AtomizeChars(JSContext *cx, const jschar *chars, size_t length,
js::InternBehavior ib = js::DoNotInternAtom);
extern JSAtom *
AtomizeString(JSContext *cx, JSString *str, js::InternBehavior ib = js::DoNotInternAtom);
inline JSAtom *
ToAtom(JSContext *cx, const js::Value &v);
bool
InternNonIntElementId(JSContext *cx, JSObject *obj, const Value &idval,
jsid *idp, MutableHandleValue vp);
inline bool
InternNonIntElementId(JSContext *cx, JSObject *obj, const Value &idval, jsid *idp)
{
RootedValue dummy(cx);
return InternNonIntElementId(cx, obj, idval, idp, &dummy);
}
template<XDRMode mode>
bool
XDRAtom(XDRState<mode> *xdr, JSAtom **atomp);
} /* namespace js */
#endif /* jsatom_h___ */
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