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/*
* Copyright (C) 2003-2019 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#pragma once
#include "ArrayConventions.h"
#include "PrivateName.h"
#include "VM.h"
#include <wtf/text/CString.h>
#include <wtf/text/UniquedStringImpl.h>
#include <wtf/text/WTFString.h>
namespace JSC {
class CallFrame;
ALWAYS_INLINE bool isIndex(uint32_t index)
{
return index <= MAX_ARRAY_INDEX;
}
template <typename CharType>
ALWAYS_INLINE std::optional<uint32_t> parseIndex(const CharType* characters, unsigned length)
{
// An empty string is not a number.
if (!length)
return std::nullopt;
// Get the first character, turning it into a digit.
uint32_t value = characters[0] - '0';
if (value > 9)
return std::nullopt;
// Check for leading zeros. If the first characher is 0, then the
// length of the string must be one - e.g. "042" is not equal to "42".
if (!value && length > 1)
return std::nullopt;
while (--length) {
// Multiply value by 10, checking for overflow out of 32 bits.
if (value > 0xFFFFFFFFU / 10)
return std::nullopt;
value *= 10;
// Get the next character, turning it into a digit.
uint32_t newValue = *(++characters) - '0';
if (newValue > 9)
return std::nullopt;
// Add in the old value, checking for overflow out of 32 bits.
newValue += value;
if (newValue < value)
return std::nullopt;
value = newValue;
}
if (!isIndex(value))
return std::nullopt;
return value;
}
ALWAYS_INLINE std::optional<uint32_t> parseIndex(StringImpl& impl)
{
if (impl.is8Bit())
return parseIndex(impl.characters8(), impl.length());
return parseIndex(impl.characters16(), impl.length());
}
class Identifier {
friend class Structure;
public:
Identifier() = default;
enum EmptyIdentifierFlag { EmptyIdentifier };
Identifier(EmptyIdentifierFlag) : m_string(StringImpl::empty()) { ASSERT(m_string.impl()->isAtom()); }
const AtomString& string() const { return m_string; }
UniquedStringImpl* impl() const { return static_cast<UniquedStringImpl*>(m_string.impl()); }
int length() const { return m_string.length(); }
CString ascii() const { return m_string.string().ascii(); }
CString utf8() const { return m_string.string().utf8(); }
// There's 2 functions to construct Identifier from string, (1) fromString and (2) fromUid.
// They have different meanings in keeping or discarding symbol-ness of strings.
// (1): fromString
// Just construct Identifier from string. String held by Identifier is always atomized.
// Symbol-ness of StringImpl*, which represents that the string is inteded to be used for ES6 Symbols, is discarded.
// So a constructed Identifier never represents a symbol.
// (2): fromUid
// `StringImpl* uid` represents ether String or Symbol property.
// fromUid keeps symbol-ness of provided StringImpl* while fromString discards it.
// Use fromUid when constructing Identifier from StringImpl* which may represent symbols.
static Identifier fromString(VM&, ASCIILiteral);
static Identifier fromString(VM&, const LChar*, int length);
static Identifier fromString(VM&, const UChar*, int length);
static Identifier fromString(VM&, const String&);
static Identifier fromString(VM&, AtomStringImpl*);
static Identifier fromString(VM&, Ref<AtomStringImpl>&&);
static Identifier fromString(VM&, const AtomString&);
static Identifier fromString(VM& vm, SymbolImpl*);
static Identifier fromString(VM& vm, const Vector<LChar>& characters) { return fromString(vm, characters.data(), characters.size()); }
static Identifier fromLatin1(VM&, const char*);
static Identifier fromUid(VM&, UniquedStringImpl* uid);
static Identifier fromUid(const PrivateName&);
static Identifier fromUid(SymbolImpl&);
static Identifier createLCharFromUChar(VM& vm, const UChar* s, int length) { return Identifier(vm, add8(vm, s, length)); }
JS_EXPORT_PRIVATE static Identifier from(VM&, unsigned y);
JS_EXPORT_PRIVATE static Identifier from(VM&, int y);
JS_EXPORT_PRIVATE static Identifier from(VM&, double y);
ALWAYS_INLINE static Identifier from(VM& vm, uint64_t y)
{
if (static_cast<uint32_t>(y) == y)
return from(vm, static_cast<uint32_t>(y));
ASSERT(static_cast<uint64_t>(static_cast<double>(y)) == y);
return from(vm, static_cast<double>(y));
}
bool isNull() const { return m_string.isNull(); }
bool isEmpty() const { return m_string.isEmpty(); }
bool isSymbol() const { return !isNull() && impl()->isSymbol(); }
bool isPrivateName() const { return isSymbol() && static_cast<const SymbolImpl*>(impl())->isPrivate(); }
friend bool operator==(const Identifier&, const Identifier&);
friend bool operator!=(const Identifier&, const Identifier&);
friend bool operator==(const Identifier&, const LChar*);
friend bool operator==(const Identifier&, const char*);
friend bool operator!=(const Identifier&, const LChar*);
friend bool operator!=(const Identifier&, const char*);
static bool equal(const StringImpl*, const LChar*);
static inline bool equal(const StringImpl*a, const char*b) { return Identifier::equal(a, reinterpret_cast<const LChar*>(b)); };
static bool equal(const StringImpl*, const LChar*, unsigned length);
static bool equal(const StringImpl*, const UChar*, unsigned length);
static bool equal(const StringImpl* a, const StringImpl* b) { return ::equal(a, b); }
// Only to be used with string literals.
JS_EXPORT_PRIVATE static Ref<AtomStringImpl> add(VM&, const char*);
void dump(PrintStream&) const;
private:
AtomString m_string;
Identifier(VM& vm, const LChar* s, int length) : m_string(add(vm, s, length)) { ASSERT(m_string.impl()->isAtom()); }
Identifier(VM& vm, const UChar* s, int length) : m_string(add(vm, s, length)) { ASSERT(m_string.impl()->isAtom()); }
ALWAYS_INLINE Identifier(VM& vm, ASCIILiteral literal) : m_string(add(vm, literal)) { ASSERT(m_string.impl()->isAtom()); }
Identifier(VM&, AtomStringImpl*);
Identifier(VM&, const AtomString&);
Identifier(VM& vm, const String& string) : m_string(add(vm, string.impl())) { ASSERT(m_string.impl()->isAtom()); }
Identifier(VM& vm, StringImpl* rep) : m_string(add(vm, rep)) { ASSERT(m_string.impl()->isAtom()); }
Identifier(VM&, Ref<AtomStringImpl>&& impl)
: m_string(WTFMove(impl))
{ }
Identifier(SymbolImpl& uid)
: m_string(&uid)
{ }
template <typename CharType>
ALWAYS_INLINE static uint32_t toUInt32FromCharacters(const CharType* characters, unsigned length, bool& ok);
static bool equal(const Identifier& a, const Identifier& b) { return a.m_string.impl() == b.m_string.impl(); }
static bool equal(const Identifier& a, const LChar* b) { return equal(a.m_string.impl(), b); }
template <typename T> static Ref<AtomStringImpl> add(VM&, const T*, int length);
static Ref<AtomStringImpl> add8(VM&, const UChar*, int length);
template <typename T> ALWAYS_INLINE static constexpr bool canUseSingleCharacterString(T);
static Ref<AtomStringImpl> add(VM&, StringImpl*);
static Ref<AtomStringImpl> add(VM&, ASCIILiteral);
#ifndef NDEBUG
JS_EXPORT_PRIVATE static void checkCurrentAtomStringTable(VM&);
#else
JS_EXPORT_PRIVATE NO_RETURN_DUE_TO_CRASH static void checkCurrentAtomStringTable(VM&);
#endif
};
template <> ALWAYS_INLINE constexpr bool Identifier::canUseSingleCharacterString(LChar)
{
static_assert(maxSingleCharacterString == 0xff);
return true;
}
template <> ALWAYS_INLINE constexpr bool Identifier::canUseSingleCharacterString(UChar c)
{
return (c <= maxSingleCharacterString);
}
template <typename T>
Ref<AtomStringImpl> Identifier::add(VM& vm, const T* s, int length)
{
if (length == 1) {
T c = s[0];
if (canUseSingleCharacterString(c))
return vm.smallStrings.singleCharacterStringRep(c);
}
if (!length)
return *static_cast<AtomStringImpl*>(StringImpl::empty());
return *AtomStringImpl::add(s, length);
}
inline Ref<AtomStringImpl> Identifier::add(VM& vm, ASCIILiteral literal)
{
if (literal.length() == 1)
return vm.smallStrings.singleCharacterStringRep(literal.characterAt(0));
return AtomStringImpl::add(literal);
}
inline bool operator==(const Identifier& a, const Identifier& b)
{
return Identifier::equal(a, b);
}
inline bool operator!=(const Identifier& a, const Identifier& b)
{
return !Identifier::equal(a, b);
}
inline bool operator==(const Identifier& a, const LChar* b)
{
return Identifier::equal(a, b);
}
inline bool operator==(const Identifier& a, const char* b)
{
return Identifier::equal(a, reinterpret_cast<const LChar*>(b));
}
inline bool operator!=(const Identifier& a, const LChar* b)
{
return !Identifier::equal(a, b);
}
inline bool operator!=(const Identifier& a, const char* b)
{
return !Identifier::equal(a, reinterpret_cast<const LChar*>(b));
}
inline bool Identifier::equal(const StringImpl* r, const LChar* s)
{
return WTF::equal(r, s);
}
inline bool Identifier::equal(const StringImpl* r, const LChar* s, unsigned length)
{
return WTF::equal(r, s, length);
}
inline bool Identifier::equal(const StringImpl* r, const UChar* s, unsigned length)
{
return WTF::equal(r, s, length);
}
ALWAYS_INLINE std::optional<uint32_t> parseIndex(const Identifier& identifier)
{
auto uid = identifier.impl();
if (!uid)
return std::nullopt;
if (uid->isSymbol())
return std::nullopt;
return parseIndex(*uid);
}
JSValue identifierToJSValue(VM&, const Identifier&);
// This will stringify private symbols. When leaking JSValues to
// non-internal code, make sure to use this function and not the above one.
JSValue identifierToSafePublicJSValue(VM&, const Identifier&);
// FIXME: It may be better for this to just be a typedef for PtrHash, since PtrHash may be cheaper to
// compute than loading the StringImpl's hash from memory. That change would also reduce the likelihood of
// crashes in code that somehow dangled a StringImpl.
// https://bugs.webkit.org/show_bug.cgi?id=150137
struct IdentifierRepHash : PtrHash<RefPtr<UniquedStringImpl>> {
static unsigned hash(const RefPtr<UniquedStringImpl>& key) { return key->existingSymbolAwareHash(); }
static unsigned hash(UniquedStringImpl* key) { return key->existingSymbolAwareHash(); }
static constexpr bool hasHashInValue = true;
};
struct IdentifierMapIndexHashTraits : HashTraits<int> {
static int emptyValue() { return std::numeric_limits<int>::max(); }
static constexpr bool emptyValueIsZero = false;
};
typedef HashSet<RefPtr<UniquedStringImpl>, IdentifierRepHash> IdentifierSet;
typedef HashMap<RefPtr<UniquedStringImpl>, int, IdentifierRepHash, HashTraits<RefPtr<UniquedStringImpl>>, IdentifierMapIndexHashTraits> IdentifierMap;
typedef HashMap<UniquedStringImpl*, int, IdentifierRepHash, HashTraits<UniquedStringImpl*>, IdentifierMapIndexHashTraits> BorrowedIdentifierMap;
} // namespace JSC
namespace WTF {
template <> struct VectorTraits<JSC::Identifier> : SimpleClassVectorTraits { };
} // namespace WTF