diff options
Diffstat (limited to 'Source/JavaScriptCore/runtime/JSString.h')
| -rw-r--r-- | Source/JavaScriptCore/runtime/JSString.h | 1075 |
1 files changed, 647 insertions, 428 deletions
diff --git a/Source/JavaScriptCore/runtime/JSString.h b/Source/JavaScriptCore/runtime/JSString.h index 448ffc484..3fc677da7 100644 --- a/Source/JavaScriptCore/runtime/JSString.h +++ b/Source/JavaScriptCore/runtime/JSString.h @@ -1,7 +1,7 @@ /* * Copyright (C) 1999-2001 Harri Porten (porten@kde.org) * Copyright (C) 2001 Peter Kelly (pmk@post.com) - * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2014 Apple Inc. All rights reserved. + * Copyright (C) 2003-2017 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 @@ -20,8 +20,7 @@ * */ -#ifndef JSString_h -#define JSString_h +#pragma once #include "CallFrame.h" #include "CommonIdentifiers.h" @@ -30,538 +29,758 @@ #include "PropertySlot.h" #include "Structure.h" #include <array> +#include <wtf/text/StringView.h> namespace JSC { - class JSString; - class JSRopeString; - class LLIntOffsetsExtractor; +class JSString; +class JSRopeString; +class LLIntOffsetsExtractor; + +JSString* jsEmptyString(VM*); +JSString* jsEmptyString(ExecState*); +JSString* jsString(VM*, const String&); // returns empty string if passed null string +JSString* jsString(ExecState*, const String&); // returns empty string if passed null string + +JSString* jsSingleCharacterString(VM*, UChar); +JSString* jsSingleCharacterString(ExecState*, UChar); +JSString* jsSubstring(VM*, const String&, unsigned offset, unsigned length); +JSString* jsSubstring(ExecState*, const String&, unsigned offset, unsigned length); + +// Non-trivial strings are two or more characters long. +// These functions are faster than just calling jsString. +JSString* jsNontrivialString(VM*, const String&); +JSString* jsNontrivialString(ExecState*, const String&); +JSString* jsNontrivialString(ExecState*, String&&); + +// Should be used for strings that are owned by an object that will +// likely outlive the JSValue this makes, such as the parse tree or a +// DOM object that contains a String +JSString* jsOwnedString(VM*, const String&); +JSString* jsOwnedString(ExecState*, const String&); + +JSRopeString* jsStringBuilder(VM*); + +bool isJSString(JSCell*); +bool isJSString(JSValue); +JSString* asString(JSValue); + +struct StringViewWithUnderlyingString { + StringView view; + String underlyingString; +}; + +class JSString : public JSCell { +public: + friend class JIT; + friend class VM; + friend class SpecializedThunkJIT; + friend class JSRopeString; + friend class MarkStack; + friend class SlotVisitor; + friend struct ThunkHelpers; + + typedef JSCell Base; + static const unsigned StructureFlags = Base::StructureFlags | OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero | StructureIsImmortal | OverridesToThis; + + static const bool needsDestruction = true; + static void destroy(JSCell*); + + // We specialize the string subspace to get the fastest possible sweep. This wouldn't be + // necessary if JSString didn't have a destructor. + template<typename> + static Subspace* subspaceFor(VM& vm) + { + return &vm.stringSpace; + } + + static const unsigned MaxLength = std::numeric_limits<int32_t>::max(); + +private: + JSString(VM& vm, Ref<StringImpl>&& value) + : JSCell(vm, vm.stringStructure.get()) + , m_flags(0) + , m_value(WTFMove(value)) + { + } - JSString* jsEmptyString(VM*); - JSString* jsEmptyString(ExecState*); - JSString* jsString(VM*, const String&); // returns empty string if passed null string - JSString* jsString(ExecState*, const String&); // returns empty string if passed null string + JSString(VM& vm) + : JSCell(vm, vm.stringStructure.get()) + , m_flags(0) + { + } - JSString* jsSingleCharacterString(VM*, UChar); - JSString* jsSingleCharacterString(ExecState*, UChar); - JSString* jsSingleCharacterSubstring(ExecState*, const String&, unsigned offset); - JSString* jsSubstring(VM*, const String&, unsigned offset, unsigned length); - JSString* jsSubstring(ExecState*, const String&, unsigned offset, unsigned length); + void finishCreation(VM& vm, size_t length) + { + ASSERT(!m_value.isNull()); + Base::finishCreation(vm); + setLength(length); + setIs8Bit(m_value.impl()->is8Bit()); + } - // Non-trivial strings are two or more characters long. - // These functions are faster than just calling jsString. - JSString* jsNontrivialString(VM*, const String&); - JSString* jsNontrivialString(ExecState*, const String&); + void finishCreation(VM& vm, size_t length, size_t cost) + { + ASSERT(!m_value.isNull()); + Base::finishCreation(vm); + setLength(length); + setIs8Bit(m_value.impl()->is8Bit()); + Heap::heap(this)->reportExtraMemoryAllocated(cost); + } - // Should be used for strings that are owned by an object that will - // likely outlive the JSValue this makes, such as the parse tree or a - // DOM object that contains a String - JSString* jsOwnedString(VM*, const String&); - JSString* jsOwnedString(ExecState*, const String&); +protected: + void finishCreation(VM& vm) + { + Base::finishCreation(vm); + setLength(0); + setIs8Bit(true); + } - JSRopeString* jsStringBuilder(VM*); +public: + static JSString* create(VM& vm, Ref<StringImpl>&& value) + { + unsigned length = value->length(); + size_t cost = value->cost(); + JSString* newString = new (NotNull, allocateCell<JSString>(vm.heap)) JSString(vm, WTFMove(value)); + newString->finishCreation(vm, length, cost); + return newString; + } + static JSString* createHasOtherOwner(VM& vm, Ref<StringImpl>&& value) + { + size_t length = value->length(); + JSString* newString = new (NotNull, allocateCell<JSString>(vm.heap)) JSString(vm, WTFMove(value)); + newString->finishCreation(vm, length); + return newString; + } - class JSString : public JSCell { - public: - friend class JIT; - friend class VM; - friend class SpecializedThunkJIT; - friend class JSRopeString; - friend class MarkStack; - friend class SlotVisitor; - friend struct ThunkHelpers; + Identifier toIdentifier(ExecState*) const; + AtomicString toAtomicString(ExecState*) const; + RefPtr<AtomicStringImpl> toExistingAtomicString(ExecState*) const; - typedef JSCell Base; + StringViewWithUnderlyingString viewWithUnderlyingString(ExecState&) const; - static const bool needsDestruction = true; - static const bool hasImmortalStructure = true; - static void destroy(JSCell*); + inline bool equal(ExecState*, JSString* other) const; + const String& value(ExecState*) const; + const String& tryGetValue() const; + const StringImpl* tryGetValueImpl() const; + ALWAYS_INLINE unsigned length() const { return m_length; } + ALWAYS_INLINE static bool isValidLength(size_t length) + { + // While length is of type unsigned, the runtime and compilers are all + // expecting that m_length is a positive value <= INT_MAX. + // FIXME: Look into making the max length UINT_MAX to match StringImpl's max length. + // https://bugs.webkit.org/show_bug.cgi?id=163955 + return length <= std::numeric_limits<int32_t>::max(); + } - private: - JSString(VM& vm, PassRefPtr<StringImpl> value) - : JSCell(vm, vm.stringStructure.get()) - , m_flags(0) - , m_value(value) - { - } + JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const; + bool toBoolean() const { return !!length(); } + bool getPrimitiveNumber(ExecState*, double& number, JSValue&) const; + JSObject* toObject(ExecState*, JSGlobalObject*) const; + double toNumber(ExecState*) const; - JSString(VM& vm) - : JSCell(vm, vm.stringStructure.get()) - , m_flags(0) - { - } + bool getStringPropertySlot(ExecState*, PropertyName, PropertySlot&); + bool getStringPropertySlot(ExecState*, unsigned propertyName, PropertySlot&); + bool getStringPropertyDescriptor(ExecState*, PropertyName, PropertyDescriptor&); - void finishCreation(VM& vm, size_t length) - { - ASSERT(!m_value.isNull()); - Base::finishCreation(vm); - m_length = length; - setIs8Bit(m_value.impl()->is8Bit()); - vm.m_newStringsSinceLastHashCons++; - } + bool canGetIndex(unsigned i) { return i < length(); } + JSString* getIndex(ExecState*, unsigned); - void finishCreation(VM& vm, size_t length, size_t cost) - { - ASSERT(!m_value.isNull()); - Base::finishCreation(vm); - m_length = length; - setIs8Bit(m_value.impl()->is8Bit()); - Heap::heap(this)->reportExtraMemoryCost(cost); - vm.m_newStringsSinceLastHashCons++; - } + static Structure* createStructure(VM&, JSGlobalObject*, JSValue); - protected: - void finishCreation(VM& vm) - { - Base::finishCreation(vm); - m_length = 0; - setIs8Bit(true); - vm.m_newStringsSinceLastHashCons++; - } - - public: - static JSString* create(VM& vm, PassRefPtr<StringImpl> value) - { - ASSERT(value); - int32_t length = value->length(); - RELEASE_ASSERT(length >= 0); - size_t cost = value->cost(); - JSString* newString = new (NotNull, allocateCell<JSString>(vm.heap)) JSString(vm, value); - newString->finishCreation(vm, length, cost); - return newString; - } - static JSString* createHasOtherOwner(VM& vm, PassRefPtr<StringImpl> value) - { - ASSERT(value); - size_t length = value->length(); - JSString* newString = new (NotNull, allocateCell<JSString>(vm.heap)) JSString(vm, value); - newString->finishCreation(vm, length); - return newString; - } - - const String& value(ExecState*) const; - const String& tryGetValue() const; - const StringImpl* tryGetValueImpl() const; - unsigned length() { return m_length; } - - JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const; - JS_EXPORT_PRIVATE bool toBoolean() const; - bool getPrimitiveNumber(ExecState*, double& number, JSValue&) const; - JSObject* toObject(ExecState*, JSGlobalObject*) const; - double toNumber(ExecState*) const; - - bool getStringPropertySlot(ExecState*, PropertyName, PropertySlot&); - bool getStringPropertySlot(ExecState*, unsigned propertyName, PropertySlot&); - bool getStringPropertyDescriptor(ExecState*, PropertyName, PropertyDescriptor&); - - bool canGetIndex(unsigned i) { return i < m_length; } - JSString* getIndex(ExecState*, unsigned); - - static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue proto) - { - return Structure::create(vm, globalObject, proto, TypeInfo(StringType, OverridesGetOwnPropertySlot | InterceptsGetOwnPropertySlotByIndexEvenWhenLengthIsNotZero), info()); - } - - static size_t offsetOfLength() { return OBJECT_OFFSETOF(JSString, m_length); } - static size_t offsetOfFlags() { return OBJECT_OFFSETOF(JSString, m_flags); } - static size_t offsetOfValue() { return OBJECT_OFFSETOF(JSString, m_value); } + static size_t offsetOfLength() { return OBJECT_OFFSETOF(JSString, m_length); } + static size_t offsetOfFlags() { return OBJECT_OFFSETOF(JSString, m_flags); } + static size_t offsetOfValue() { return OBJECT_OFFSETOF(JSString, m_value); } - DECLARE_EXPORT_INFO; + DECLARE_EXPORT_INFO; - static void visitChildren(JSCell*, SlotVisitor&); + static void dumpToStream(const JSCell*, PrintStream&); + static size_t estimatedSize(JSCell*); + static void visitChildren(JSCell*, SlotVisitor&); - enum { - HashConsLock = 1u << 2, - IsHashConsSingleton = 1u << 1, - Is8Bit = 1u - }; + enum { + Is8Bit = 1u + }; - protected: - friend class JSValue; - - bool isRope() const { return m_value.isNull(); } - bool is8Bit() const { return m_flags & Is8Bit; } - void setIs8Bit(bool flag) - { - if (flag) - m_flags |= Is8Bit; - else - m_flags &= ~Is8Bit; - } - bool shouldTryHashCons(); - bool isHashConsSingleton() const { return m_flags & IsHashConsSingleton; } - void clearHashConsSingleton() { m_flags &= ~IsHashConsSingleton; } - void setHashConsSingleton() { m_flags |= IsHashConsSingleton; } - bool tryHashConsLock(); - void releaseHashConsLock(); - - unsigned m_flags; - - // A string is represented either by a String or a rope of fibers. - unsigned m_length; - mutable String m_value; +protected: + friend class JSValue; - private: - friend class LLIntOffsetsExtractor; - - static JSValue toThis(JSCell*, ExecState*, ECMAMode); - - String& string() { ASSERT(!isRope()); return m_value; } + JS_EXPORT_PRIVATE bool equalSlowCase(ExecState*, JSString* other) const; + bool isRope() const { return m_value.isNull(); } + bool isSubstring() const; + bool is8Bit() const { return m_flags & Is8Bit; } + void setIs8Bit(bool flag) const + { + if (flag) + m_flags |= Is8Bit; + else + m_flags &= ~Is8Bit; + } - friend JSValue jsString(ExecState*, JSString*, JSString*); - friend JSString* jsSubstring(ExecState*, JSString*, unsigned offset, unsigned length); - }; + ALWAYS_INLINE void setLength(unsigned length) + { + RELEASE_ASSERT(isValidLength(length)); + m_length = length; + } - class JSRopeString : public JSString { - friend class JSString; +private: + mutable unsigned m_flags; - friend JSRopeString* jsStringBuilder(VM*); + // A string is represented either by a String or a rope of fibers. + unsigned m_length; + mutable String m_value; - class RopeBuilder { - public: - RopeBuilder(VM& vm) - : m_vm(vm) - , m_jsString(jsStringBuilder(&vm)) - , m_index(0) - { - } + friend class LLIntOffsetsExtractor; - bool append(JSString* jsString) - { - if (m_index == JSRopeString::s_maxInternalRopeLength) - expand(); - if (static_cast<int32_t>(m_jsString->length() + jsString->length()) < 0) { - m_jsString = nullptr; - return false; - } - m_jsString->append(m_vm, m_index++, jsString); - return true; - } + static JSValue toThis(JSCell*, ExecState*, ECMAMode); - JSRopeString* release() - { - RELEASE_ASSERT(m_jsString); - JSRopeString* tmp = m_jsString; - m_jsString = 0; - return tmp; - } + String& string() { ASSERT(!isRope()); return m_value; } + StringView unsafeView(ExecState&) const; - unsigned length() { return m_jsString->m_length; } + friend JSString* jsString(ExecState*, JSString*, JSString*); + friend JSString* jsSubstring(ExecState*, JSString*, unsigned offset, unsigned length); +}; - private: - void expand(); - - VM& m_vm; - JSRopeString* m_jsString; - size_t m_index; - }; - - private: - JSRopeString(VM& vm) - : JSString(vm) - { - } +// NOTE: This class cannot override JSString's destructor. JSString's destructor is called directly +// from JSStringSubspace:: +class JSRopeString final : public JSString { + friend class JSString; - void finishCreation(VM& vm, JSString* s1, JSString* s2) - { - Base::finishCreation(vm); - m_length = s1->length() + s2->length(); - setIs8Bit(s1->is8Bit() && s2->is8Bit()); - m_fibers[0].set(vm, this, s1); - m_fibers[1].set(vm, this, s2); - } - - void finishCreation(VM& vm, JSString* s1, JSString* s2, JSString* s3) - { - Base::finishCreation(vm); - m_length = s1->length() + s2->length() + s3->length(); - setIs8Bit(s1->is8Bit() && s2->is8Bit() && s3->is8Bit()); - m_fibers[0].set(vm, this, s1); - m_fibers[1].set(vm, this, s2); - m_fibers[2].set(vm, this, s3); - } + friend JSRopeString* jsStringBuilder(VM*); - void finishCreation(VM& vm) - { - JSString::finishCreation(vm); - } - - void append(VM& vm, size_t index, JSString* jsString) +public: + class RopeBuilder { + public: + RopeBuilder(VM& vm) + : m_vm(vm) + , m_jsString(jsStringBuilder(&vm)) + , m_index(0) { - m_fibers[index].set(vm, this, jsString); - m_length += jsString->m_length; - RELEASE_ASSERT(static_cast<int32_t>(m_length) >= 0); - setIs8Bit(is8Bit() && jsString->is8Bit()); } - static JSRopeString* createNull(VM& vm) + bool append(JSString* jsString) { - JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap)) JSRopeString(vm); - newString->finishCreation(vm); - return newString; + if (m_index == JSRopeString::s_maxInternalRopeLength) + expand(); + if (static_cast<int32_t>(m_jsString->length() + jsString->length()) < 0) { + m_jsString = nullptr; + return false; + } + m_jsString->append(m_vm, m_index++, jsString); + return true; } - public: - static JSString* create(VM& vm, JSString* s1, JSString* s2) - { - JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap)) JSRopeString(vm); - newString->finishCreation(vm, s1, s2); - return newString; - } - static JSString* create(VM& vm, JSString* s1, JSString* s2, JSString* s3) + JSRopeString* release() { - JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap)) JSRopeString(vm); - newString->finishCreation(vm, s1, s2, s3); - return newString; + RELEASE_ASSERT(m_jsString); + JSRopeString* tmp = m_jsString; + m_jsString = 0; + return tmp; } - void visitFibers(SlotVisitor&); - - static ptrdiff_t offsetOfFibers() { return OBJECT_OFFSETOF(JSRopeString, m_fibers); } + unsigned length() const { return m_jsString->length(); } - static const unsigned s_maxInternalRopeLength = 3; - private: - friend JSValue jsStringFromRegisterArray(ExecState*, Register*, unsigned); - friend JSValue jsStringFromArguments(ExecState*, JSValue); - - JS_EXPORT_PRIVATE void resolveRope(ExecState*) const; - void resolveRopeSlowCase8(LChar*) const; - void resolveRopeSlowCase(UChar*) const; - void outOfMemory(ExecState*) const; - - JS_EXPORT_PRIVATE JSString* getIndexSlowCase(ExecState*, unsigned); + void expand(); - mutable std::array<WriteBarrier<JSString>, s_maxInternalRopeLength> m_fibers; + VM& m_vm; + JSRopeString* m_jsString; + size_t m_index; }; +private: + ALWAYS_INLINE JSRopeString(VM& vm) + : JSString(vm) + { + } - inline const StringImpl* JSString::tryGetValueImpl() const + void finishCreation(VM& vm, JSString* s1, JSString* s2) { - return m_value.impl(); + Base::finishCreation(vm); + ASSERT(!sumOverflows<int32_t>(s1->length(), s2->length())); + setLength(s1->length() + s2->length()); + setIs8Bit(s1->is8Bit() && s2->is8Bit()); + setIsSubstring(false); + fiber(0).set(vm, this, s1); + fiber(1).set(vm, this, s2); + fiber(2).clear(); } - JSString* asString(JSValue); + void finishCreation(VM& vm, JSString* s1, JSString* s2, JSString* s3) + { + Base::finishCreation(vm); + ASSERT(!sumOverflows<int32_t>(s1->length(), s2->length(), s3->length())); + setLength(s1->length() + s2->length() + s3->length()); + setIs8Bit(s1->is8Bit() && s2->is8Bit() && s3->is8Bit()); + setIsSubstring(false); + fiber(0).set(vm, this, s1); + fiber(1).set(vm, this, s2); + fiber(2).set(vm, this, s3); + } - inline JSString* asString(JSValue value) + void finishCreation(VM& vm, ExecState* exec, JSString* base, unsigned offset, unsigned length) { - ASSERT(value.asCell()->isString()); - return jsCast<JSString*>(value.asCell()); + Base::finishCreation(vm); + RELEASE_ASSERT(!sumOverflows<int32_t>(offset, length)); + RELEASE_ASSERT(offset + length <= base->length()); + setLength(length); + setIs8Bit(base->is8Bit()); + setIsSubstring(true); + if (base->isSubstring()) { + JSRopeString* baseRope = jsCast<JSRopeString*>(base); + substringBase().set(vm, this, baseRope->substringBase().get()); + substringOffset() = baseRope->substringOffset() + offset; + } else { + substringBase().set(vm, this, base); + substringOffset() = offset; + + // For now, let's not allow substrings with a rope base. + // Resolve non-substring rope bases so we don't have to deal with it. + // FIXME: Evaluate if this would be worth adding more branches. + if (base->isRope()) + jsCast<JSRopeString*>(base)->resolveRope(exec); + } } - inline JSString* jsEmptyString(VM* vm) + ALWAYS_INLINE void finishCreationSubstringOfResolved(VM& vm, JSString* base, unsigned offset, unsigned length) { - return vm->smallStrings.emptyString(); + Base::finishCreation(vm); + RELEASE_ASSERT(!sumOverflows<int32_t>(offset, length)); + RELEASE_ASSERT(offset + length <= base->length()); + setLength(length); + setIs8Bit(base->is8Bit()); + setIsSubstring(true); + substringBase().set(vm, this, base); + substringOffset() = offset; } - ALWAYS_INLINE JSString* jsSingleCharacterString(VM* vm, UChar c) + void finishCreation(VM& vm) { - if (c <= maxSingleCharacterString) - return vm->smallStrings.singleCharacterString(c); - return JSString::create(*vm, String(&c, 1).impl()); + JSString::finishCreation(vm); + setIsSubstring(false); + fiber(0).clear(); + fiber(1).clear(); + fiber(2).clear(); } - ALWAYS_INLINE JSString* jsSingleCharacterSubstring(ExecState* exec, const String& s, unsigned offset) + void append(VM& vm, size_t index, JSString* jsString) { - VM* vm = &exec->vm(); - ASSERT(offset < static_cast<unsigned>(s.length())); - UChar c = s.characterAt(offset); - if (c <= maxSingleCharacterString) - return vm->smallStrings.singleCharacterString(c); - return JSString::create(*vm, StringImpl::create(s.impl(), offset, 1)); + fiber(index).set(vm, this, jsString); + setLength(length() + jsString->length()); + setIs8Bit(is8Bit() && jsString->is8Bit()); } - inline JSString* jsNontrivialString(VM* vm, const String& s) + static JSRopeString* createNull(VM& vm) { - ASSERT(s.length() > 1); - return JSString::create(*vm, s.impl()); + JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap)) JSRopeString(vm); + newString->finishCreation(vm); + return newString; } - inline const String& JSString::value(ExecState* exec) const +public: + static JSString* create(VM& vm, ExecState* exec, JSString* base, unsigned offset, unsigned length) { - if (isRope()) - static_cast<const JSRopeString*>(this)->resolveRope(exec); - return m_value; + JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap)) JSRopeString(vm); + newString->finishCreation(vm, exec, base, offset, length); + return newString; } - inline const String& JSString::tryGetValue() const + ALWAYS_INLINE static JSString* createSubstringOfResolved(VM& vm, GCDeferralContext* deferralContext, JSString* base, unsigned offset, unsigned length) { - if (isRope()) - static_cast<const JSRopeString*>(this)->resolveRope(0); - return m_value; + JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap, deferralContext)) JSRopeString(vm); + newString->finishCreationSubstringOfResolved(vm, base, offset, length); + return newString; } - inline JSString* JSString::getIndex(ExecState* exec, unsigned i) + ALWAYS_INLINE static JSString* createSubstringOfResolved(VM& vm, JSString* base, unsigned offset, unsigned length) { - ASSERT(canGetIndex(i)); - if (isRope()) - return static_cast<JSRopeString*>(this)->getIndexSlowCase(exec, i); - ASSERT(i < m_value.length()); - return jsSingleCharacterSubstring(exec, m_value, i); + return createSubstringOfResolved(vm, nullptr, base, offset, length); } - inline JSString* jsString(VM* vm, const String& s) + void visitFibers(SlotVisitor&); + + static ptrdiff_t offsetOfFibers() { return OBJECT_OFFSETOF(JSRopeString, u); } + + static const unsigned s_maxInternalRopeLength = 3; + +private: + static JSString* create(VM& vm, JSString* s1, JSString* s2) { - int size = s.length(); - if (!size) - return vm->smallStrings.emptyString(); - if (size == 1) { - UChar c = s.characterAt(0); - if (c <= maxSingleCharacterString) - return vm->smallStrings.singleCharacterString(c); - } - return JSString::create(*vm, s.impl()); + JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap)) JSRopeString(vm); + newString->finishCreation(vm, s1, s2); + return newString; + } + static JSString* create(VM& vm, JSString* s1, JSString* s2, JSString* s3) + { + JSRopeString* newString = new (NotNull, allocateCell<JSRopeString>(vm.heap)) JSRopeString(vm); + newString->finishCreation(vm, s1, s2, s3); + return newString; } - inline JSString* jsSubstring(ExecState* exec, JSString* s, unsigned offset, unsigned length) + friend JSValue jsStringFromRegisterArray(ExecState*, Register*, unsigned); + friend JSValue jsStringFromArguments(ExecState*, JSValue); + + JS_EXPORT_PRIVATE void resolveRope(ExecState*) const; + JS_EXPORT_PRIVATE void resolveRopeToAtomicString(ExecState*) const; + JS_EXPORT_PRIVATE RefPtr<AtomicStringImpl> resolveRopeToExistingAtomicString(ExecState*) const; + void resolveRopeSlowCase8(LChar*) const; + void resolveRopeSlowCase(UChar*) const; + void outOfMemory(ExecState*) const; + void resolveRopeInternal8(LChar*) const; + void resolveRopeInternal8NoSubstring(LChar*) const; + void resolveRopeInternal16(UChar*) const; + void resolveRopeInternal16NoSubstring(UChar*) const; + void clearFibers() const; + StringView unsafeView(ExecState&) const; + StringViewWithUnderlyingString viewWithUnderlyingString(ExecState&) const; + + WriteBarrierBase<JSString>& fiber(unsigned i) const { - ASSERT(offset <= static_cast<unsigned>(s->length())); - ASSERT(length <= static_cast<unsigned>(s->length())); - ASSERT(offset + length <= static_cast<unsigned>(s->length())); - VM* vm = &exec->vm(); - if (!length) - return vm->smallStrings.emptyString(); - return jsSubstring(vm, s->value(exec), offset, length); + ASSERT(!isSubstring()); + ASSERT(i < s_maxInternalRopeLength); + return u[i].string; } - inline JSString* jsSubstring8(VM* vm, const String& s, unsigned offset, unsigned length) + WriteBarrierBase<JSString>& substringBase() const { - ASSERT(offset <= static_cast<unsigned>(s.length())); - ASSERT(length <= static_cast<unsigned>(s.length())); - ASSERT(offset + length <= static_cast<unsigned>(s.length())); - if (!length) - return vm->smallStrings.emptyString(); - if (length == 1) { - UChar c = s.characterAt(offset); - if (c <= maxSingleCharacterString) - return vm->smallStrings.singleCharacterString(c); - } - return JSString::createHasOtherOwner(*vm, StringImpl::create8(s.impl(), offset, length)); + return u[1].string; } - inline JSString* jsSubstring(VM* vm, const String& s, unsigned offset, unsigned length) + uintptr_t& substringOffset() const { - ASSERT(offset <= static_cast<unsigned>(s.length())); - ASSERT(length <= static_cast<unsigned>(s.length())); - ASSERT(offset + length <= static_cast<unsigned>(s.length())); - if (!length) - return vm->smallStrings.emptyString(); - if (length == 1) { - UChar c = s.characterAt(offset); - if (c <= maxSingleCharacterString) - return vm->smallStrings.singleCharacterString(c); - } - return JSString::createHasOtherOwner(*vm, StringImpl::create(s.impl(), offset, length)); + return u[2].number; } - inline JSString* jsOwnedString(VM* vm, const String& s) + static uintptr_t notSubstringSentinel() { - int size = s.length(); - if (!size) - return vm->smallStrings.emptyString(); - if (size == 1) { - UChar c = s.characterAt(0); - if (c <= maxSingleCharacterString) - return vm->smallStrings.singleCharacterString(c); - } - return JSString::createHasOtherOwner(*vm, s.impl()); + return 0; } - inline JSRopeString* jsStringBuilder(VM* vm) + static uintptr_t substringSentinel() { - return JSRopeString::createNull(*vm); + return 1; } - inline JSString* jsEmptyString(ExecState* exec) { return jsEmptyString(&exec->vm()); } - inline JSString* jsString(ExecState* exec, const String& s) { return jsString(&exec->vm(), s); } - inline JSString* jsSingleCharacterString(ExecState* exec, UChar c) { return jsSingleCharacterString(&exec->vm(), c); } - inline JSString* jsSubstring8(ExecState* exec, const String& s, unsigned offset, unsigned length) { return jsSubstring8(&exec->vm(), s, offset, length); } - inline JSString* jsSubstring(ExecState* exec, const String& s, unsigned offset, unsigned length) { return jsSubstring(&exec->vm(), s, offset, length); } - inline JSString* jsNontrivialString(ExecState* exec, const String& s) { return jsNontrivialString(&exec->vm(), s); } - inline JSString* jsOwnedString(ExecState* exec, const String& s) { return jsOwnedString(&exec->vm(), s); } + bool isSubstring() const + { + return u[0].number == substringSentinel(); + } - ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, PropertyName propertyName, PropertySlot& slot) + void setIsSubstring(bool isSubstring) { - if (propertyName == exec->propertyNames().length) { - slot.setValue(this, DontEnum | DontDelete | ReadOnly, jsNumber(m_length)); - return true; - } + u[0].number = isSubstring ? substringSentinel() : notSubstringSentinel(); + } - unsigned i = propertyName.asIndex(); - if (i < m_length) { - ASSERT(i != PropertyName::NotAnIndex); // No need for an explicit check, the above test would always fail! - slot.setValue(this, DontDelete | ReadOnly, getIndex(exec, i)); - return true; - } + mutable union { + uintptr_t number; + WriteBarrierBase<JSString> string; + } u[s_maxInternalRopeLength]; + + + friend JSString* jsString(ExecState*, JSString*, JSString*); + friend JSString* jsString(ExecState*, JSString*, JSString*, JSString*); + friend JSString* jsString(ExecState*, const String&, const String&, const String&); +}; + +JS_EXPORT_PRIVATE JSString* jsStringWithCacheSlowCase(VM&, StringImpl&); + +inline const StringImpl* JSString::tryGetValueImpl() const +{ + return m_value.impl(); +} + +inline JSString* asString(JSValue value) +{ + ASSERT(value.asCell()->isString()); + return jsCast<JSString*>(value.asCell()); +} + +// This MUST NOT GC. +inline JSString* jsEmptyString(VM* vm) +{ + return vm->smallStrings.emptyString(); +} + +ALWAYS_INLINE JSString* jsSingleCharacterString(VM* vm, UChar c) +{ + if (c <= maxSingleCharacterString) + return vm->smallStrings.singleCharacterString(c); + return JSString::create(*vm, StringImpl::create(&c, 1)); +} + +inline JSString* jsNontrivialString(VM* vm, const String& s) +{ + ASSERT(s.length() > 1); + return JSString::create(*vm, *s.impl()); +} + +inline JSString* jsNontrivialString(VM* vm, String&& s) +{ + ASSERT(s.length() > 1); + return JSString::create(*vm, s.releaseImpl().releaseNonNull()); +} + +ALWAYS_INLINE Identifier JSString::toIdentifier(ExecState* exec) const +{ + return Identifier::fromString(exec, toAtomicString(exec)); +} + +ALWAYS_INLINE AtomicString JSString::toAtomicString(ExecState* exec) const +{ + if (isRope()) + static_cast<const JSRopeString*>(this)->resolveRopeToAtomicString(exec); + return AtomicString(m_value); +} + +ALWAYS_INLINE RefPtr<AtomicStringImpl> JSString::toExistingAtomicString(ExecState* exec) const +{ + if (isRope()) + return static_cast<const JSRopeString*>(this)->resolveRopeToExistingAtomicString(exec); + if (m_value.impl()->isAtomic()) + return static_cast<AtomicStringImpl*>(m_value.impl()); + return AtomicStringImpl::lookUp(m_value.impl()); +} + +inline const String& JSString::value(ExecState* exec) const +{ + if (isRope()) + static_cast<const JSRopeString*>(this)->resolveRope(exec); + return m_value; +} + +inline const String& JSString::tryGetValue() const +{ + if (isRope()) + static_cast<const JSRopeString*>(this)->resolveRope(0); + return m_value; +} + +inline JSString* JSString::getIndex(ExecState* exec, unsigned i) +{ + ASSERT(canGetIndex(i)); + return jsSingleCharacterString(exec, unsafeView(*exec)[i]); +} + +inline JSString* jsString(VM* vm, const String& s) +{ + int size = s.length(); + if (!size) + return vm->smallStrings.emptyString(); + if (size == 1) { + UChar c = s.characterAt(0); + if (c <= maxSingleCharacterString) + return vm->smallStrings.singleCharacterString(c); + } + return JSString::create(*vm, *s.impl()); +} + +inline JSString* jsSubstring(VM& vm, ExecState* exec, JSString* s, unsigned offset, unsigned length) +{ + ASSERT(offset <= static_cast<unsigned>(s->length())); + ASSERT(length <= static_cast<unsigned>(s->length())); + ASSERT(offset + length <= static_cast<unsigned>(s->length())); + if (!length) + return vm.smallStrings.emptyString(); + if (!offset && length == s->length()) + return s; + return JSRopeString::create(vm, exec, s, offset, length); +} + +inline JSString* jsSubstringOfResolved(VM& vm, GCDeferralContext* deferralContext, JSString* s, unsigned offset, unsigned length) +{ + ASSERT(offset <= static_cast<unsigned>(s->length())); + ASSERT(length <= static_cast<unsigned>(s->length())); + ASSERT(offset + length <= static_cast<unsigned>(s->length())); + if (!length) + return vm.smallStrings.emptyString(); + if (!offset && length == s->length()) + return s; + return JSRopeString::createSubstringOfResolved(vm, deferralContext, s, offset, length); +} + +inline JSString* jsSubstringOfResolved(VM& vm, JSString* s, unsigned offset, unsigned length) +{ + return jsSubstringOfResolved(vm, nullptr, s, offset, length); +} + +inline JSString* jsSubstring(ExecState* exec, JSString* s, unsigned offset, unsigned length) +{ + return jsSubstring(exec->vm(), exec, s, offset, length); +} + +inline JSString* jsSubstring(VM* vm, const String& s, unsigned offset, unsigned length) +{ + ASSERT(offset <= static_cast<unsigned>(s.length())); + ASSERT(length <= static_cast<unsigned>(s.length())); + ASSERT(offset + length <= static_cast<unsigned>(s.length())); + if (!length) + return vm->smallStrings.emptyString(); + if (length == 1) { + UChar c = s.characterAt(offset); + if (c <= maxSingleCharacterString) + return vm->smallStrings.singleCharacterString(c); + } + return JSString::createHasOtherOwner(*vm, StringImpl::createSubstringSharingImpl(*s.impl(), offset, length)); +} - return false; +inline JSString* jsOwnedString(VM* vm, const String& s) +{ + int size = s.length(); + if (!size) + return vm->smallStrings.emptyString(); + if (size == 1) { + UChar c = s.characterAt(0); + if (c <= maxSingleCharacterString) + return vm->smallStrings.singleCharacterString(c); + } + return JSString::createHasOtherOwner(*vm, *s.impl()); +} + +inline JSRopeString* jsStringBuilder(VM* vm) +{ + return JSRopeString::createNull(*vm); +} + +inline JSString* jsEmptyString(ExecState* exec) { return jsEmptyString(&exec->vm()); } +inline JSString* jsString(ExecState* exec, const String& s) { return jsString(&exec->vm(), s); } +inline JSString* jsSingleCharacterString(ExecState* exec, UChar c) { return jsSingleCharacterString(&exec->vm(), c); } +inline JSString* jsSubstring(ExecState* exec, const String& s, unsigned offset, unsigned length) { return jsSubstring(&exec->vm(), s, offset, length); } +inline JSString* jsNontrivialString(ExecState* exec, const String& s) { return jsNontrivialString(&exec->vm(), s); } +inline JSString* jsNontrivialString(ExecState* exec, String&& s) { return jsNontrivialString(&exec->vm(), WTFMove(s)); } +inline JSString* jsOwnedString(ExecState* exec, const String& s) { return jsOwnedString(&exec->vm(), s); } + +ALWAYS_INLINE JSString* jsStringWithCache(ExecState* exec, const String& s) +{ + VM& vm = exec->vm(); + StringImpl* stringImpl = s.impl(); + if (!stringImpl || !stringImpl->length()) + return jsEmptyString(&vm); + + if (stringImpl->length() == 1) { + UChar singleCharacter = (*stringImpl)[0u]; + if (singleCharacter <= maxSingleCharacterString) + return vm.smallStrings.singleCharacterString(static_cast<unsigned char>(singleCharacter)); } - - ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot) - { - if (propertyName < m_length) { - slot.setValue(this, DontDelete | ReadOnly, getIndex(exec, propertyName)); - return true; - } - return false; + if (JSString* lastCachedString = vm.lastCachedString.get()) { + if (lastCachedString->tryGetValueImpl() == stringImpl) + return lastCachedString; } - inline bool isJSString(JSValue v) { return v.isCell() && v.asCell()->classInfo() == JSString::info(); } + return jsStringWithCacheSlowCase(vm, *stringImpl); +} - // --- JSValue inlines ---------------------------- - - inline bool JSValue::toBoolean(ExecState* exec) const - { - if (isInt32()) - return asInt32(); - if (isDouble()) - return asDouble() > 0.0 || asDouble() < 0.0; // false for NaN - if (isCell()) - return asCell()->toBoolean(exec); - return isTrue(); // false, null, and undefined all convert to false. +ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, PropertyName propertyName, PropertySlot& slot) +{ + if (propertyName == exec->propertyNames().length) { + slot.setValue(this, DontEnum | DontDelete | ReadOnly, jsNumber(length())); + return true; } - inline JSString* JSValue::toString(ExecState* exec) const - { - if (isString()) - return jsCast<JSString*>(asCell()); - return toStringSlowCase(exec); + std::optional<uint32_t> index = parseIndex(propertyName); + if (index && index.value() < length()) { + slot.setValue(this, DontDelete | ReadOnly, getIndex(exec, index.value())); + return true; } - inline String JSValue::toWTFString(ExecState* exec) const - { - if (isString()) - return static_cast<JSString*>(asCell())->value(exec); - return toWTFStringSlowCase(exec); - } + return false; +} - ALWAYS_INLINE String inlineJSValueNotStringtoString(const JSValue& value, ExecState* exec) - { - VM& vm = exec->vm(); - if (value.isInt32()) - return vm.numericStrings.add(value.asInt32()); - if (value.isDouble()) - return vm.numericStrings.add(value.asDouble()); - if (value.isTrue()) - return vm.propertyNames->trueKeyword.string(); - if (value.isFalse()) - return vm.propertyNames->falseKeyword.string(); - if (value.isNull()) - return vm.propertyNames->nullKeyword.string(); - if (value.isUndefined()) - return vm.propertyNames->undefinedKeyword.string(); - return value.toString(exec)->value(exec); - } - - ALWAYS_INLINE String JSValue::toWTFStringInline(ExecState* exec) const - { - if (isString()) - return static_cast<JSString*>(asCell())->value(exec); +ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot) +{ + if (propertyName < length()) { + slot.setValue(this, DontDelete | ReadOnly, getIndex(exec, propertyName)); + return true; + } - return inlineJSValueNotStringtoString(*this, exec); + return false; +} + +inline bool isJSString(JSCell* cell) +{ + return cell->type() == StringType; +} + +inline bool isJSString(JSValue v) +{ + return v.isCell() && isJSString(v.asCell()); +} + +ALWAYS_INLINE StringView JSRopeString::unsafeView(ExecState& state) const +{ + if (isSubstring()) { + if (is8Bit()) + return StringView(substringBase()->m_value.characters8() + substringOffset(), length()); + return StringView(substringBase()->m_value.characters16() + substringOffset(), length()); + } + resolveRope(&state); + return m_value; +} + +ALWAYS_INLINE StringViewWithUnderlyingString JSRopeString::viewWithUnderlyingString(ExecState& state) const +{ + if (isSubstring()) { + auto& base = substringBase()->m_value; + if (is8Bit()) + return { { base.characters8() + substringOffset(), length() }, base }; + return { { base.characters16() + substringOffset(), length() }, base }; } + resolveRope(&state); + return { m_value, m_value }; +} + +ALWAYS_INLINE StringView JSString::unsafeView(ExecState& state) const +{ + if (isRope()) + return static_cast<const JSRopeString*>(this)->unsafeView(state); + return m_value; +} + +ALWAYS_INLINE StringViewWithUnderlyingString JSString::viewWithUnderlyingString(ExecState& state) const +{ + if (isRope()) + return static_cast<const JSRopeString&>(*this).viewWithUnderlyingString(state); + return { m_value, m_value }; +} + +inline bool JSString::isSubstring() const +{ + return isRope() && static_cast<const JSRopeString*>(this)->isSubstring(); +} + +// --- JSValue inlines ---------------------------- + +inline bool JSValue::toBoolean(ExecState* exec) const +{ + if (isInt32()) + return asInt32(); + if (isDouble()) + return asDouble() > 0.0 || asDouble() < 0.0; // false for NaN + if (isCell()) + return asCell()->toBoolean(exec); + return isTrue(); // false, null, and undefined all convert to false. +} + +inline JSString* JSValue::toString(ExecState* exec) const +{ + if (isString()) + return asString(asCell()); + bool returnEmptyStringOnError = true; + return toStringSlowCase(exec, returnEmptyStringOnError); +} + +inline JSString* JSValue::toStringOrNull(ExecState* exec) const +{ + if (isString()) + return asString(asCell()); + bool returnEmptyStringOnError = false; + return toStringSlowCase(exec, returnEmptyStringOnError); +} + +inline String JSValue::toWTFString(ExecState* exec) const +{ + if (isString()) + return static_cast<JSString*>(asCell())->value(exec); + return toWTFStringSlowCase(exec); +} } // namespace JSC - -#endif // JSString_h |