/*

 *  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&); 

    class JSString : public JSCell {

        friend class JIT;

        friend struct VPtrSet;

    public:

        JSString(JSGlobalData* globalData, const UString& value)

            : JSCell(globalData->stringStructure.get())

            , m_value(value)

        {

            Heap::heap(this)->reportExtraMemoryCost(value.cost());

        }

        enum HasOtherOwnerType { HasOtherOwner };

        JSString(JSGlobalData* globalData, const UString& value, HasOtherOwnerType)

            : JSCell(globalData->stringStructure.get())

            , m_value(value)

        {

        }

        JSString(JSGlobalData* globalData, PassRefPtr<UString::Rep> value, HasOtherOwnerType)

            : JSCell(globalData->stringStructure.get())

            , m_value(value)

        {

        }

        const UString& value() const { return m_value; }

        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 < static_cast<unsigned>(m_value.size()); }

        JSString* getIndex(JSGlobalData*, unsigned);

        static PassRefPtr<Structure> createStructure(JSValue proto) { return Structure::create(proto, TypeInfo(StringType, OverridesGetOwnPropertySlot | NeedsThisConversion)); }

    private:

        enum VPtrStealingHackType { VPtrStealingHack };

        JSString(VPtrStealingHackType) 

            : JSCell(0)

        {

        }

        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&);

        UString m_value;

    };

    JSString* asString(JSValue);

    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 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 new (globalData) JSString(globalData, UString::Rep::create(s.rep(), offset, 1));

    }

    inline JSString* jsNontrivialString(JSGlobalData* globalData, const char* s)

    {

        ASSERT(s);

        ASSERT(s[0]);

        ASSERT(s[1]);

        return new (globalData) JSString(globalData, s);

    }

    inline JSString* jsNontrivialString(JSGlobalData* globalData, const UString& s)

    {

        ASSERT(s.size() > 1);

        return new (globalData) JSString(globalData, s);

    }

    inline JSString* JSString::getIndex(JSGlobalData* globalData, unsigned i)

    {

        ASSERT(canGetIndex(i));

        return jsSingleCharacterSubstring(globalData, m_value, 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 new (globalData) JSString(globalData, s);

    }

    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 new (globalData) JSString(globalData, UString::Rep::create(s.rep(), offset, length));

    }

    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 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_value.size()));

            return true;

        }

        bool isStrictUInt32;

        unsigned i = propertyName.toStrictUInt32(&isStrictUInt32);

        if (isStrictUInt32 && i < static_cast<unsigned>(m_value.size())) {

            slot.setValue(jsSingleCharacterSubstring(exec, m_value, i));

            return true;

        }

        return false;

    }

    ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)

    {

        if (propertyName < static_cast<unsigned>(m_value.size())) {

            slot.setValue(jsSingleCharacterSubstring(exec, m_value, 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();

        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);

    }

} // namespace JSC

#endif // JSString_h