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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* 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 */
/* JavaScript RegExp objects. */
#ifndef vm_RegExpObject_h
#define vm_RegExpObject_h
#include "builtin/SelfHostingDefines.h"
#include "js/RegExpFlags.h"
#include "proxy/Proxy.h"
#include "vm/JSAtomState.h"
#include "vm/JSContext.h"
#include "vm/RegExpShared.h"
#include "vm/Shape.h"
* JavaScript Regular Expressions
* There are several engine concepts associated with a single logical regexp:
* RegExpObject:
* The JS-visible object whose .[[Class]] equals "RegExp".
* RegExpShared:
* The compiled representation of the regexp (lazily created, cleared
* during some forms of GC).
* RegExpZone:
* Owns all RegExpShared instances in a zone.
namespace js {
class GenericPrinter;
class JSONPrinter;
extern RegExpObject* RegExpAlloc(JSContext* cx, NewObjectKind newKind,
HandleObject proto = nullptr);
extern JSObject* CloneRegExpObject(JSContext* cx, Handle<RegExpObject*> regex);
class RegExpObject : public NativeObject {
static const unsigned LAST_INDEX_SLOT = 0;
static const unsigned SOURCE_SLOT = 1;
static const unsigned FLAGS_SLOT = 2;
static_assert(RegExpObject::FLAGS_SLOT == REGEXP_FLAGS_SLOT,
"FLAGS_SLOT values should be in sync with self-hosted JS");
static RegExpObject* create(JSContext* cx, Handle<JSAtom*> source,
NewObjectKind newKind);
static const unsigned SHARED_SLOT = 3;
static const unsigned RESERVED_SLOTS = 4;
// This must match RESERVED_SLOTS. See assertions in CloneRegExpObject.
static constexpr gc::AllocKind AllocKind = gc::AllocKind::OBJECT4_BACKGROUND;
static const JSClass class_;
static const JSClass protoClass_;
// The maximum number of pairs a MatchResult can have, without having to
// allocate a bigger MatchResult.
static const size_t MaxPairCount = 14;
template <typename CharT>
static RegExpObject* create(JSContext* cx, const CharT* chars, size_t length,
JS::RegExpFlags flags, NewObjectKind newKind);
// This variant assumes that the characters have already previously been
// syntax checked.
static RegExpObject* createSyntaxChecked(JSContext* cx,
Handle<JSAtom*> source,
JS::RegExpFlags flags,
NewObjectKind newKind);
static RegExpObject* create(JSContext* cx, Handle<JSAtom*> source,
JS::RegExpFlags flags, NewObjectKind newKind);
* Compute the initial shape to associate with fresh RegExp objects,
* encoding their initial properties. Return the shape after
* changing |obj|'s last property to it.
static SharedShape* assignInitialShape(JSContext* cx,
Handle<RegExpObject*> obj);
/* Accessors. */
static constexpr size_t lastIndexSlot() { return LAST_INDEX_SLOT; }
static constexpr size_t offsetOfLastIndex() {
return getFixedSlotOffset(lastIndexSlot());
static bool isInitialShape(RegExpObject* rx) {
// RegExpObject has a non-configurable lastIndex property, so there must be
// at least one property. Even though lastIndex is non-configurable, it can
// be made non-writable, so we have to check if it's still writable.
PropertyInfoWithKey prop = rx->getLastProperty();
return prop.isDataProperty() && prop.slot() == LAST_INDEX_SLOT &&
const Value& getLastIndex() const { return getReservedSlot(LAST_INDEX_SLOT); }
void setLastIndex(JSContext* cx, int32_t lastIndex) {
MOZ_ASSERT(lastIndex >= 0);
"can't infallibly set a non-writable lastIndex on a "
"RegExp that's been exposed to script");
setReservedSlot(LAST_INDEX_SLOT, Int32Value(lastIndex));
void zeroLastIndex(JSContext* cx) { setLastIndex(cx, 0); }
static JSLinearString* toString(JSContext* cx, Handle<RegExpObject*> obj);
JSAtom* getSource() const {
return &getReservedSlot(SOURCE_SLOT).toString()->asAtom();
void setSource(JSAtom* source) {
setReservedSlot(SOURCE_SLOT, StringValue(source));
/* Flags. */
static constexpr size_t flagsSlot() { return FLAGS_SLOT; }
static constexpr size_t offsetOfFlags() {
return getFixedSlotOffset(flagsSlot());
static constexpr size_t offsetOfShared() {
return getFixedSlotOffset(SHARED_SLOT);
JS::RegExpFlags getFlags() const {
return JS::RegExpFlags(getFixedSlot(FLAGS_SLOT).toInt32());
void setFlags(JS::RegExpFlags flags) {
setFixedSlot(FLAGS_SLOT, Int32Value(flags.value()));
bool hasIndices() const { return getFlags().hasIndices(); }
bool global() const { return getFlags().global(); }
bool ignoreCase() const { return getFlags().ignoreCase(); }
bool multiline() const { return getFlags().multiline(); }
bool dotAll() const { return getFlags().dotAll(); }
bool unicode() const { return getFlags().unicode(); }
bool unicodeSets() const { return getFlags().unicodeSets(); }
bool sticky() const { return getFlags().sticky(); }
bool isGlobalOrSticky() const {
JS::RegExpFlags flags = getFlags();
return || flags.sticky();
static bool isOriginalFlagGetter(JSNative native, JS::RegExpFlags* mask);
static RegExpShared* getShared(JSContext* cx, Handle<RegExpObject*> regexp);
bool hasShared() const { return !getFixedSlot(SHARED_SLOT).isUndefined(); }
RegExpShared* getShared() const {
return static_cast<RegExpShared*>(getFixedSlot(SHARED_SLOT).toGCThing());
void setShared(RegExpShared* shared) {
setFixedSlot(SHARED_SLOT, PrivateGCThingValue(shared));
void clearShared() { setFixedSlot(SHARED_SLOT, UndefinedValue()); }
void initIgnoringLastIndex(JSAtom* source, JS::RegExpFlags flags);
// NOTE: This method is *only* safe to call on RegExps that haven't been
// exposed to script, because it requires that the "lastIndex"
// property be writable.
void initAndZeroLastIndex(JSAtom* source, JS::RegExpFlags flags,
JSContext* cx);
#if defined(DEBUG) || defined(JS_JITSPEW)
void dumpOwnFields(js::JSONPrinter& json) const;
void dumpOwnStringContent(js::GenericPrinter& out) const;
* Precondition: the syntax for |source| has already been validated.
* Side effect: sets the private field.
static RegExpShared* createShared(JSContext* cx,
Handle<RegExpObject*> regexp);
/* Call setShared in preference to setPrivate. */
void setPrivate(void* priv) = delete;
* Parse regexp flags. Report an error and return false if an invalid
* sequence of flags is encountered (repeat/invalid flag).
* N.B. flagStr must be rooted.
bool ParseRegExpFlags(JSContext* cx, JSString* flagStr,
JS::RegExpFlags* flagsOut);
// Assuming GetBuiltinClass(obj) is ESClass::RegExp, return a RegExpShared for
// obj.
inline RegExpShared* RegExpToShared(JSContext* cx, HandleObject obj) {
if (obj->is<RegExpObject>()) {
return RegExpObject::getShared(cx,<RegExpObject>());
return Proxy::regexp_toShared(cx, obj);
/* Escape all slashes and newlines in the given string. */
extern JSLinearString* EscapeRegExpPattern(JSContext* cx, Handle<JSAtom*> src);
template <typename CharT>
extern bool HasRegExpMetaChars(const CharT* chars, size_t length);
extern bool StringHasRegExpMetaChars(JSLinearString* str);
} /* namespace js */
#endif /* vm_RegExpObject_h */