/*
* 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 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.
*
*/
#ifndef JSString_h
#define JSString_h
#include "CallFrame.h"
#include "CommonIdentifiers.h"
#include "Identifier.h"
#include "JSNumberCell.h"
#include "PropertyDescriptor.h"
#include "PropertySlot.h"
namespace JSC {
class JSString;
JSString* jsEmptyString(JSGlobalData*);
JSString* jsEmptyString(ExecState*);
JSString* jsString(JSGlobalData*, const UString&); // returns empty string if passed null string
JSString* jsString(ExecState*, const UString&); // returns empty string if passed null string
JSString* jsSingleCharacterString(JSGlobalData*, UChar);
JSString* jsSingleCharacterString(ExecState*, UChar);
JSString* jsSingleCharacterSubstring(JSGlobalData*, const UString&, unsigned offset);
JSString* jsSingleCharacterSubstring(ExecState*, const UString&, unsigned offset);
JSString* jsSubstring(JSGlobalData*, const UString&, unsigned offset, unsigned length);
JSString* jsSubstring(ExecState*, const UString&, unsigned offset, unsigned length);
// Non-trivial strings are two or more characters long.
// These functions are faster than just calling jsString.
JSString* jsNontrivialString(JSGlobalData*, const UString&);
JSString* jsNontrivialString(ExecState*, const UString&);
JSString* jsNontrivialString(JSGlobalData*, const char*);
JSString* jsNontrivialString(ExecState*, const char*);
// 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 UString
JSString* jsOwnedString(JSGlobalData*, const UString&);
JSString* jsOwnedString(ExecState*, const UString&);
typedef void (*JSStringFinalizerCallback)(JSString*, void* context);
JSString* jsStringWithFinalizer(ExecState*, const UString&, JSStringFinalizerCallback callback, void* context);
class JS_EXPORTCLASS JSString : public JSCell {
public:
friend class JIT;
friend class JSGlobalData;
// A Rope is a string composed of a set of substrings.
class Rope : public RefCounted<Rope> {
public:
// A Rope is composed from a set of smaller strings called Fibers.
// Each Fiber in a rope is either UString::Rep or another Rope.
class Fiber {
public:
Fiber() : m_value(0) {}
Fiber(UString::Rep* string) : m_value(reinterpret_cast<intptr_t>(string)) {}
Fiber(Rope* rope) : m_value(reinterpret_cast<intptr_t>(rope) | 1) {}
Fiber(void* nonFiber) : m_value(reinterpret_cast<intptr_t>(nonFiber)) {}
void deref()
{
if (isRope())
rope()->deref();
else
string()->deref();
}
Fiber& ref()
{
if (isString())
string()->ref();
else
rope()->ref();
return *this;
}
unsigned refAndGetLength()
{
if (isString()) {
UString::Rep* rep = string();
return rep->ref()->size();
} else {
Rope* r = rope();
r->ref();
return r->stringLength();
}
}
bool isRope() { return m_value & 1; }
Rope* rope() { return reinterpret_cast<Rope*>(m_value & ~1); }
bool isString() { return !isRope(); }
UString::Rep* string() { return reinterpret_cast<UString::Rep*>(m_value); }
void* nonFiber() { return reinterpret_cast<void*>(m_value); }
private:
intptr_t m_value;
};
// Creates a Rope comprising of 'ropeLength' Fibers.
// The Rope is constructed in an uninitialized state - initialize must be called for each Fiber in the Rope.
static PassRefPtr<Rope> createOrNull(unsigned ropeLength)
{
void* allocation;
if (tryFastMalloc(sizeof(Rope) + (ropeLength - 1) * sizeof(Fiber)).getValue(allocation))
return adoptRef(new (allocation) Rope(ropeLength));
return 0;
}
~Rope();
void destructNonRecursive();
void append(unsigned &index, Fiber& fiber)
{
m_fibers[index++] = fiber;
m_stringLength += fiber.refAndGetLength();
}
void append(unsigned &index, const UString& string)
{
UString::Rep* rep = string.rep();
m_fibers[index++] = Fiber(rep);
m_stringLength += rep->ref()->size();
}
void append(unsigned& index, JSString* jsString)
{
if (jsString->isRope()) {
for (unsigned i = 0; i < jsString->m_ropeLength; ++i)
append(index, jsString->m_fibers[i]);
} else
append(index, jsString->string());
}
unsigned ropeLength() { return m_ropeLength; }
unsigned stringLength() { return m_stringLength; }
Fiber& fibers(unsigned index) { return m_fibers[index]; }
private:
Rope(unsigned ropeLength) : m_ropeLength(ropeLength), m_stringLength(0) {}
void* operator new(size_t, void* inPlace) { return inPlace; }
unsigned m_ropeLength;
unsigned m_stringLength;
Fiber m_fibers[1];
};
ALWAYS_INLINE JSString(JSGlobalData* globalData, const UString& value)
: JSCell(globalData->stringStructure.get())
, m_stringLength(value.size())
, m_value(value)
, m_ropeLength(0)
{
Heap::heap(this)->reportExtraMemoryCost(value.cost());
}
enum HasOtherOwnerType { HasOtherOwner };
JSString(JSGlobalData* globalData, const UString& value, HasOtherOwnerType)
: JSCell(globalData->stringStructure.get())
, m_stringLength(value.size())
, m_value(value)
, m_ropeLength(0)
{
}
JSString(JSGlobalData* globalData, PassRefPtr<UString::Rep> value, HasOtherOwnerType)
: JSCell(globalData->stringStructure.get())
, m_stringLength(value->size())
, m_value(value)
, m_ropeLength(0)
{
}
JSString(JSGlobalData* globalData, PassRefPtr<JSString::Rope> rope)
: JSCell(globalData->stringStructure.get())
, m_stringLength(rope->stringLength())
, m_ropeLength(1)
{
m_fibers[0] = rope.releaseRef();
}
// This constructor constructs a new string by concatenating s1 & s2.
// This should only be called with ropeLength <= 3.
JSString(JSGlobalData* globalData, unsigned ropeLength, JSString* s1, JSString* s2)
: JSCell(globalData->stringStructure.get())
, m_stringLength(s1->length() + s2->length())
, m_ropeLength(ropeLength)
{
ASSERT(ropeLength <= s_maxInternalRopeLength);
unsigned index = 0;
appendStringInConstruct(index, s1);
appendStringInConstruct(index, s2);
ASSERT(ropeLength == index);
}
// This constructor constructs a new string by concatenating s1 & s2.
// This should only be called with ropeLength <= 3.
JSString(JSGlobalData* globalData, unsigned ropeLength, JSString* s1, const UString& u2)
: JSCell(globalData->stringStructure.get())
, m_stringLength(s1->length() + u2.size())
, m_ropeLength(ropeLength)
{
ASSERT(ropeLength <= s_maxInternalRopeLength);
unsigned index = 0;
appendStringInConstruct(index, s1);
appendStringInConstruct(index, u2);
ASSERT(ropeLength == index);
}
// This constructor constructs a new string by concatenating s1 & s2.
// This should only be called with ropeLength <= 3.
JSString(JSGlobalData* globalData, unsigned ropeLength, const UString& u1, JSString* s2)
: JSCell(globalData->stringStructure.get())
, m_stringLength(u1.size() + s2->length())
, m_ropeLength(ropeLength)
{
ASSERT(ropeLength <= s_maxInternalRopeLength);
unsigned index = 0;
appendStringInConstruct(index, u1);
appendStringInConstruct(index, s2);
ASSERT(ropeLength == index);
}
// This constructor constructs a new string by concatenating v1, v2 & v3.
// This should only be called with ropeLength <= 3 ... which since every
// value must require a ropeLength of at least one implies that the length
// for each value must be exactly 1!
JSString(ExecState* exec, JSValue v1, JSValue v2, JSValue v3)
: JSCell(exec->globalData().stringStructure.get())
, m_stringLength(0)
, m_ropeLength(s_maxInternalRopeLength)
{
unsigned index = 0;
appendValueInConstructAndIncrementLength(exec, index, v1);
appendValueInConstructAndIncrementLength(exec, index, v2);
appendValueInConstructAndIncrementLength(exec, index, v3);
ASSERT(index == s_maxInternalRopeLength);
}
JSString(JSGlobalData* globalData, const UString& value, JSStringFinalizerCallback finalizer, void* context)
: JSCell(globalData->stringStructure.get())
, m_stringLength(value.size())
, m_value(value)
, m_ropeLength(0)
{
// nasty hack because we can't union non-POD types
m_fibers[0] = reinterpret_cast<void*>(reinterpret_cast<ptrdiff_t>(finalizer));
m_fibers[1] = context;
Heap::heap(this)->reportExtraMemoryCost(value.cost());
}
~JSString()
{
ASSERT(vptr() == JSGlobalData::jsStringVPtr);
for (unsigned i = 0; i < m_ropeLength; ++i)
m_fibers[i].deref();
if (!m_ropeLength && m_fibers[0].nonFiber()) {
JSStringFinalizerCallback finalizer = reinterpret_cast<JSStringFinalizerCallback>(m_fibers[0].nonFiber());
finalizer(this, m_fibers[1].nonFiber());
}
}
const UString& value(ExecState* exec) const
{
if (isRope())
resolveRope(exec);
return m_value;
}
const UString tryGetValue() const
{
// If this is a rope, m_value should be null -
// if this is not a rope, m_value should be non-null.
ASSERT(isRope() == m_value.isNull());
return m_value;
}
unsigned length() { return m_stringLength; }
bool getStringPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
bool getStringPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
bool getStringPropertyDescriptor(ExecState*, const Identifier& propertyName, PropertyDescriptor&);
bool canGetIndex(unsigned i) { return i < m_stringLength; }
JSString* getIndex(ExecState*, unsigned);
static PassRefPtr<Structure> createStructure(JSValue proto) { return Structure::create(proto, TypeInfo(StringType, OverridesGetOwnPropertySlot | NeedsThisConversion), AnonymousSlotCount); }
private:
enum VPtrStealingHackType { VPtrStealingHack };
JSString(VPtrStealingHackType)
: JSCell(0)
, m_ropeLength(0)
{
}
void resolveRope(ExecState*) const;
void appendStringInConstruct(unsigned& index, const UString& string)
{
m_fibers[index++] = Rope::Fiber(string.rep()->ref());
}
void appendStringInConstruct(unsigned& index, JSString* jsString)
{
if (jsString->isRope()) {
for (unsigned i = 0; i < jsString->m_ropeLength; ++i)
m_fibers[index++] = jsString->m_fibers[i].ref();
} else
appendStringInConstruct(index, jsString->string());
}
void appendValueInConstructAndIncrementLength(ExecState* exec, unsigned& index, JSValue v)
{
if (v.isString()) {
ASSERT(asCell(v)->isString());
JSString* s = static_cast<JSString*>(asCell(v));
ASSERT(s->ropeLength() == 1);
appendStringInConstruct(index, s);
m_stringLength += s->length();
} else {
UString u(v.toString(exec));
m_fibers[index++] = Rope::Fiber(u.rep()->ref());
m_stringLength += u.size();
}
}
virtual JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
virtual bool getPrimitiveNumber(ExecState*, double& number, JSValue& value);
virtual bool toBoolean(ExecState*) const;
virtual double toNumber(ExecState*) const;
virtual JSObject* toObject(ExecState*) const;
virtual UString toString(ExecState*) const;
virtual JSObject* toThisObject(ExecState*) const;
virtual UString toThisString(ExecState*) const;
virtual JSString* toThisJSString(ExecState*);
// Actually getPropertySlot, not getOwnPropertySlot (see JSCell).
virtual bool getOwnPropertySlot(ExecState*, const Identifier& propertyName, PropertySlot&);
virtual bool getOwnPropertySlot(ExecState*, unsigned propertyName, PropertySlot&);
virtual bool getOwnPropertyDescriptor(ExecState*, const Identifier&, PropertyDescriptor&);
static const unsigned s_maxInternalRopeLength = 3;
// A string is represented either by a UString or a Rope.
unsigned m_stringLength;
mutable UString m_value;
mutable unsigned m_ropeLength;
mutable Rope::Fiber m_fibers[s_maxInternalRopeLength];
bool isRope() const { return m_ropeLength; }
UString& string() { ASSERT(!isRope()); return m_value; }
unsigned ropeLength() { return m_ropeLength ? m_ropeLength : 1; }
friend JSValue jsString(ExecState* exec, JSString* s1, JSString* s2);
friend JSValue jsString(ExecState* exec, const UString& u1, JSString* s2);
friend JSValue jsString(ExecState* exec, JSString* s1, const UString& u2);
friend JSValue jsString(ExecState* exec, Register* strings, unsigned count);
friend JSValue jsString(ExecState* exec, JSValue thisValue, const ArgList& args);
friend JSString* jsStringWithFinalizer(ExecState*, const UString&, JSStringFinalizerCallback callback, void* context);
};
JSString* asString(JSValue);
// When an object is created from a different DLL, MSVC changes vptr to a "local" one right after invoking a constructor,
// see <http://groups.google.com/group/microsoft.public.vc.language/msg/55cdcefeaf770212>.
// This breaks isJSString(), and we don't need that hack anyway, so we change vptr back to primary one.
// The below function must be called by any inline function that invokes a JSString constructor.
#if COMPILER(MSVC) && !defined(BUILDING_JavaScriptCore)
inline JSString* fixupVPtr(JSGlobalData* globalData, JSString* string) { string->setVPtr(globalData->jsStringVPtr); return string; }
#else
inline JSString* fixupVPtr(JSGlobalData*, JSString* string) { return string; }
#endif
inline JSString* asString(JSValue value)
{
ASSERT(asCell(value)->isString());
return static_cast<JSString*>(asCell(value));
}
inline JSString* jsEmptyString(JSGlobalData* globalData)
{
return globalData->smallStrings.emptyString(globalData);
}
inline JSString* jsSingleCharacterString(JSGlobalData* globalData, UChar c)
{
if (c <= 0xFF)
return globalData->smallStrings.singleCharacterString(globalData, c);
return fixupVPtr(globalData, new (globalData) JSString(globalData, UString(&c, 1)));
}
inline JSString* jsSingleCharacterSubstring(JSGlobalData* globalData, const UString& s, unsigned offset)
{
ASSERT(offset < static_cast<unsigned>(s.size()));
UChar c = s.data()[offset];
if (c <= 0xFF)
return globalData->smallStrings.singleCharacterString(globalData, c);
return fixupVPtr(globalData, new (globalData) JSString(globalData, UString(UString::Rep::create(s.rep(), offset, 1))));
}
inline JSString* jsNontrivialString(JSGlobalData* globalData, const char* s)
{
ASSERT(s);
ASSERT(s[0]);
ASSERT(s[1]);
return fixupVPtr(globalData, new (globalData) JSString(globalData, s));
}
inline JSString* jsNontrivialString(JSGlobalData* globalData, const UString& s)
{
ASSERT(s.size() > 1);
return fixupVPtr(globalData, new (globalData) JSString(globalData, s));
}
inline JSString* JSString::getIndex(ExecState* exec, unsigned i)
{
ASSERT(canGetIndex(i));
return jsSingleCharacterSubstring(&exec->globalData(), value(exec), i);
}
inline JSString* jsString(JSGlobalData* globalData, const UString& s)
{
int size = s.size();
if (!size)
return globalData->smallStrings.emptyString(globalData);
if (size == 1) {
UChar c = s.data()[0];
if (c <= 0xFF)
return globalData->smallStrings.singleCharacterString(globalData, c);
}
return fixupVPtr(globalData, new (globalData) JSString(globalData, s));
}
inline JSString* jsStringWithFinalizer(ExecState* exec, const UString& s, JSStringFinalizerCallback callback, void* context)
{
ASSERT(s.size() && (s.size() > 1 || s.data()[0] > 0xFF));
JSGlobalData* globalData = &exec->globalData();
return fixupVPtr(globalData, new (globalData) JSString(globalData, s, callback, context));
}
inline JSString* jsSubstring(JSGlobalData* globalData, const UString& s, unsigned offset, unsigned length)
{
ASSERT(offset <= static_cast<unsigned>(s.size()));
ASSERT(length <= static_cast<unsigned>(s.size()));
ASSERT(offset + length <= static_cast<unsigned>(s.size()));
if (!length)
return globalData->smallStrings.emptyString(globalData);
if (length == 1) {
UChar c = s.data()[offset];
if (c <= 0xFF)
return globalData->smallStrings.singleCharacterString(globalData, c);
}
return fixupVPtr(globalData, new (globalData) JSString(globalData, UString(UString::Rep::create(s.rep(), offset, length)), JSString::HasOtherOwner));
}
inline JSString* jsOwnedString(JSGlobalData* globalData, const UString& s)
{
int size = s.size();
if (!size)
return globalData->smallStrings.emptyString(globalData);
if (size == 1) {
UChar c = s.data()[0];
if (c <= 0xFF)
return globalData->smallStrings.singleCharacterString(globalData, c);
}
return fixupVPtr(globalData, new (globalData) JSString(globalData, s, JSString::HasOtherOwner));
}
inline JSString* jsEmptyString(ExecState* exec) { return jsEmptyString(&exec->globalData()); }
inline JSString* jsString(ExecState* exec, const UString& s) { return jsString(&exec->globalData(), s); }
inline JSString* jsSingleCharacterString(ExecState* exec, UChar c) { return jsSingleCharacterString(&exec->globalData(), c); }
inline JSString* jsSingleCharacterSubstring(ExecState* exec, const UString& s, unsigned offset) { return jsSingleCharacterSubstring(&exec->globalData(), s, offset); }
inline JSString* jsSubstring(ExecState* exec, const UString& s, unsigned offset, unsigned length) { return jsSubstring(&exec->globalData(), s, offset, length); }
inline JSString* jsNontrivialString(ExecState* exec, const UString& s) { return jsNontrivialString(&exec->globalData(), s); }
inline JSString* jsNontrivialString(ExecState* exec, const char* s) { return jsNontrivialString(&exec->globalData(), s); }
inline JSString* jsOwnedString(ExecState* exec, const UString& s) { return jsOwnedString(&exec->globalData(), s); }
ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
{
if (propertyName == exec->propertyNames().length) {
slot.setValue(jsNumber(exec, m_stringLength));
return true;
}
bool isStrictUInt32;
unsigned i = propertyName.toStrictUInt32(&isStrictUInt32);
if (isStrictUInt32 && i < m_stringLength) {
slot.setValue(jsSingleCharacterSubstring(exec, value(exec), i));
return true;
}
return false;
}
ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
{
if (propertyName < m_stringLength) {
slot.setValue(jsSingleCharacterSubstring(exec, value(exec), propertyName));
return true;
}
return false;
}
inline bool isJSString(JSGlobalData* globalData, JSValue v) { return v.isCell() && v.asCell()->vptr() == globalData->jsStringVPtr; }
// --- JSValue inlines ----------------------------
inline JSString* JSValue::toThisJSString(ExecState* exec)
{
return isCell() ? asCell()->toThisJSString(exec) : jsString(exec, toString(exec));
}
inline UString JSValue::toString(ExecState* exec) const
{
if (isString())
return static_cast<JSString*>(asCell())->value(exec);
if (isInt32())
return exec->globalData().numericStrings.add(asInt32());
if (isDouble())
return exec->globalData().numericStrings.add(asDouble());
if (isTrue())
return "true";
if (isFalse())
return "false";
if (isNull())
return "null";
if (isUndefined())
return "undefined";
ASSERT(isCell());
return asCell()->toString(exec);
}
inline UString JSValue::toPrimitiveString(ExecState* exec) const
{
if (isString())
return static_cast<JSString*>(asCell())->value(exec);
if (isInt32())
return exec->globalData().numericStrings.add(asInt32());
if (isDouble())
return exec->globalData().numericStrings.add(asDouble());
if (isTrue())
return "true";
if (isFalse())
return "false";
if (isNull())
return "null";
if (isUndefined())
return "undefined";
ASSERT(isCell());
return asCell()->toPrimitive(exec, NoPreference).toString(exec);
}
} // namespace JSC
#endif // JSString_h