Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 478 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/runtime/JSString.h b/Source/JavaScriptCore/runtime/JSString.h
new file mode 100644
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+++ b/Source/JavaScriptCore/runtime/JSString.h
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+/*
+ *  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 "PropertyDescriptor.h"
+#include "PropertySlot.h"
+#include "Structure.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(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&); 
+
+    JSString* jsStringBuilder(JSGlobalData*);
+
+    class JS_EXPORTCLASS JSString : public JSCell {
+    public:
+        friend class JIT;
+        friend class JSGlobalData;
+        friend class SpecializedThunkJIT;
+        friend struct ThunkHelpers;
+        friend JSString* jsStringBuilder(JSGlobalData*);
+
+        typedef JSCell Base;
+
+        static void destroy(JSCell*);
+
+        class RopeBuilder {
+        public:
+            RopeBuilder(JSGlobalData& globalData)
+                : m_globalData(globalData)
+                , m_jsString(jsStringBuilder(&globalData))
+                , m_index(0)
+            {
+            }
+
+            void append(JSString* jsString)
+            {
+                if (m_index == JSString::s_maxInternalRopeLength)
+                    expand();
+                m_jsString->m_fibers[m_index++].set(m_globalData, m_jsString, jsString);
+                m_jsString->m_length += jsString->m_length;
+                m_jsString->m_is8Bit = m_jsString->m_is8Bit && jsString->m_is8Bit;
+            }
+
+            JSString* release()
+            {
+                JSString* tmp = m_jsString;
+                m_jsString = 0;
+                return tmp;
+            }
+
+            unsigned length() { return m_jsString->m_length; }
+
+        private:
+            void expand();
+
+            JSGlobalData& m_globalData;
+            JSString* m_jsString;
+            size_t m_index;
+        };
+
+    private:
+        JSString(JSGlobalData& globalData, PassRefPtr<StringImpl> value)
+            : JSCell(globalData, globalData.stringStructure.get())
+            , m_value(value)
+        {
+        }
+
+        JSString(JSGlobalData& globalData)
+            : JSCell(globalData, globalData.stringStructure.get())
+        {
+        }
+
+        void finishCreation(JSGlobalData& globalData)
+        {
+            Base::finishCreation(globalData);
+            m_length = 0;
+            m_is8Bit = true;
+        }
+
+        void finishCreation(JSGlobalData& globalData, size_t length)
+        {
+            ASSERT(!m_value.isNull());
+            Base::finishCreation(globalData);
+            m_length = length;
+            m_is8Bit = m_value.impl()->is8Bit();
+        }
+
+        void finishCreation(JSGlobalData& globalData, size_t length, size_t cost)
+        {
+            ASSERT(!m_value.isNull());
+            Base::finishCreation(globalData);
+            m_length = length;
+            m_is8Bit = m_value.impl()->is8Bit();
+            Heap::heap(this)->reportExtraMemoryCost(cost);
+        }
+
+        void finishCreation(JSGlobalData& globalData, JSString* s1, JSString* s2)
+        {
+            Base::finishCreation(globalData);
+            m_length = s1->length() + s2->length();
+            m_is8Bit = (s1->is8Bit() && s2->is8Bit());
+            m_fibers[0].set(globalData, this, s1);
+            m_fibers[1].set(globalData, this, s2);
+        }
+
+        void finishCreation(JSGlobalData& globalData, JSString* s1, JSString* s2, JSString* s3)
+        {
+            Base::finishCreation(globalData);
+            m_length = s1->length() + s2->length() + s3->length();
+            m_is8Bit = (s1->is8Bit() && s2->is8Bit() &&  s3->is8Bit());
+            m_fibers[0].set(globalData, this, s1);
+            m_fibers[1].set(globalData, this, s2);
+            m_fibers[2].set(globalData, this, s3);
+        }
+
+        static JSString* createNull(JSGlobalData& globalData)
+        {
+            JSString* newString = new (NotNull, allocateCell<JSString>(globalData.heap)) JSString(globalData);
+            newString->finishCreation(globalData);
+            return newString;
+        }
+
+    public:
+        static JSString* create(JSGlobalData& globalData, PassRefPtr<StringImpl> value)
+        {
+            ASSERT(value);
+            size_t length = value->length();
+            size_t cost = value->cost();
+            JSString* newString = new (NotNull, allocateCell<JSString>(globalData.heap)) JSString(globalData, value);
+            newString->finishCreation(globalData, length, cost);
+            return newString;
+        }
+        static JSString* create(JSGlobalData& globalData, JSString* s1, JSString* s2)
+        {
+            JSString* newString = new (NotNull, allocateCell<JSString>(globalData.heap)) JSString(globalData);
+            newString->finishCreation(globalData, s1, s2);
+            return newString;
+        }
+        static JSString* create(JSGlobalData& globalData, JSString* s1, JSString* s2, JSString* s3)
+        {
+            JSString* newString = new (NotNull, allocateCell<JSString>(globalData.heap)) JSString(globalData);
+            newString->finishCreation(globalData, s1, s2, s3);
+            return newString;
+        }
+        static JSString* createHasOtherOwner(JSGlobalData& globalData, PassRefPtr<StringImpl> value)
+        {
+            ASSERT(value);
+            size_t length = value->length();
+            JSString* newString = new (NotNull, allocateCell<JSString>(globalData.heap)) JSString(globalData, value);
+            newString->finishCreation(globalData, length);
+            return newString;
+        }
+
+        const UString& value(ExecState* exec) const
+        {
+            if (isRope())
+                resolveRope(exec);
+            return m_value;
+        }
+        const UString& tryGetValue() const
+        {
+            if (isRope())
+                resolveRope(0);
+            return m_value;
+        }
+        unsigned length() { return m_length; }
+
+        JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
+        bool toBoolean(ExecState*) const;
+        bool getPrimitiveNumber(ExecState*, double& number, JSValue&) const;
+        JSObject* toObject(ExecState*, JSGlobalObject*) const;
+        UString toString(ExecState*) const;
+        double toNumber(ExecState*) const;
+        
+        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_length; }
+        JSString* getIndex(ExecState*, unsigned);
+        JSString* getIndexSlowCase(ExecState*, unsigned);
+
+        static Structure* createStructure(JSGlobalData& globalData, JSGlobalObject* globalObject, JSValue proto)
+        {
+            return Structure::create(globalData, globalObject, proto, TypeInfo(StringType, OverridesGetOwnPropertySlot), &s_info);
+        }
+
+        static size_t offsetOfLength() { return OBJECT_OFFSETOF(JSString, m_length); }
+        static size_t offsetOfValue() { return OBJECT_OFFSETOF(JSString, m_value); }
+
+        static const ClassInfo s_info;
+
+        static void visitChildren(JSCell*, SlotVisitor&);
+
+    private:
+        void resolveRope(ExecState*) const;
+        void resolveRopeSlowCase8(LChar*) const;
+        void resolveRopeSlowCase(UChar*) const;
+        void outOfMemory(ExecState*) const;
+
+        static JSObject* toThisObject(JSCell*, ExecState*);
+
+        // Actually getPropertySlot, not getOwnPropertySlot (see JSCell).
+        static bool getOwnPropertySlot(JSCell*, ExecState*, const Identifier& propertyName, PropertySlot&);
+        static bool getOwnPropertySlotByIndex(JSCell*, ExecState*, unsigned propertyName, PropertySlot&);
+
+        static const unsigned s_maxInternalRopeLength = 3;
+
+        // A string is represented either by a UString or a rope of fibers.
+        bool m_is8Bit : 1;
+        unsigned m_length;
+        mutable UString m_value;
+        mutable FixedArray<WriteBarrier<JSString>, s_maxInternalRopeLength> m_fibers;
+
+        bool isRope() const { return m_value.isNull(); }
+        bool is8Bit() const { return m_is8Bit; }
+        UString& string() { ASSERT(!isRope()); return m_value; }
+
+        friend JSValue jsString(ExecState*, JSString*, JSString*);
+        friend JSValue jsString(ExecState*, Register*, unsigned count);
+        friend JSValue jsStringFromArguments(ExecState*, JSValue thisValue);
+        friend JSString* jsSubstring(ExecState*, JSString*, unsigned offset, unsigned length);
+    };
+
+    JSString* asString(JSValue);
+
+    inline JSString* asString(JSValue value)
+    {
+        ASSERT(value.asCell()->isString());
+        return static_cast<JSString*>(value.asCell());
+    }
+
+    inline JSString* jsEmptyString(JSGlobalData* globalData)
+    {
+        return globalData->smallStrings.emptyString(globalData);
+    }
+
+    inline JSString* jsSingleCharacterString(JSGlobalData* globalData, UChar c)
+    {
+        if (c <= maxSingleCharacterString)
+            return globalData->smallStrings.singleCharacterString(globalData, c);
+        return JSString::create(*globalData, UString(&c, 1).impl());
+    }
+
+    inline JSString* jsSingleCharacterSubstring(ExecState* exec, const UString& s, unsigned offset)
+    {
+        JSGlobalData* globalData = &exec->globalData();
+        ASSERT(offset < static_cast<unsigned>(s.length()));
+        UChar c = s[offset];
+        if (c <= maxSingleCharacterString)
+            return globalData->smallStrings.singleCharacterString(globalData, c);
+        return JSString::create(*globalData, StringImpl::create(s.impl(), offset, 1));
+    }
+
+    inline JSString* jsNontrivialString(JSGlobalData* globalData, const char* s)
+    {
+        ASSERT(s);
+        ASSERT(s[0]);
+        ASSERT(s[1]);
+        return JSString::create(*globalData, UString(s).impl());
+    }
+
+    inline JSString* jsNontrivialString(JSGlobalData* globalData, const UString& s)
+    {
+        ASSERT(s.length() > 1);
+        return JSString::create(*globalData, s.impl());
+    }
+
+    inline JSString* JSString::getIndex(ExecState* exec, unsigned i)
+    {
+        ASSERT(canGetIndex(i));
+        if (isRope())
+            return getIndexSlowCase(exec, i);
+        ASSERT(i < m_value.length());
+        return jsSingleCharacterSubstring(exec, m_value, i);
+    }
+
+    inline JSString* jsString(JSGlobalData* globalData, const UString& s)
+    {
+        int size = s.length();
+        if (!size)
+            return globalData->smallStrings.emptyString(globalData);
+        if (size == 1) {
+            UChar c = s[0];
+            if (c <= maxSingleCharacterString)
+                return globalData->smallStrings.singleCharacterString(globalData, c);
+        }
+        return JSString::create(*globalData, s.impl());
+    }
+
+    inline JSString* jsSubstring(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()));
+        JSGlobalData* globalData = &exec->globalData();
+        if (!length)
+            return globalData->smallStrings.emptyString(globalData);
+        return jsSubstring(globalData, s->value(exec), offset, length);
+    }
+
+    inline JSString* jsSubstring8(JSGlobalData* globalData, const UString& 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 globalData->smallStrings.emptyString(globalData);
+        if (length == 1) {
+            UChar c = s[offset];
+            if (c <= maxSingleCharacterString)
+                return globalData->smallStrings.singleCharacterString(globalData, c);
+        }
+        return JSString::createHasOtherOwner(*globalData, StringImpl::create8(s.impl(), offset, length));
+    }
+
+    inline JSString* jsSubstring(JSGlobalData* globalData, const UString& 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 globalData->smallStrings.emptyString(globalData);
+        if (length == 1) {
+            UChar c = s[offset];
+            if (c <= maxSingleCharacterString)
+                return globalData->smallStrings.singleCharacterString(globalData, c);
+        }
+        return JSString::createHasOtherOwner(*globalData, StringImpl::create(s.impl(), offset, length));
+    }
+
+    inline JSString* jsOwnedString(JSGlobalData* globalData, const UString& s)
+    {
+        int size = s.length();
+        if (!size)
+            return globalData->smallStrings.emptyString(globalData);
+        if (size == 1) {
+            UChar c = s[0];
+            if (c <= maxSingleCharacterString)
+                return globalData->smallStrings.singleCharacterString(globalData, c);
+        }
+        return JSString::createHasOtherOwner(*globalData, s.impl());
+    }
+
+    inline JSString* jsStringBuilder(JSGlobalData* globalData)
+    {
+        return JSString::createNull(*globalData);
+    }
+
+    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* jsSubstring8(ExecState* exec, const UString& s, unsigned offset, unsigned length) { return jsSubstring8(&exec->globalData(), s, offset, length); }
+    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(m_length));
+            return true;
+        }
+
+        bool isStrictUInt32;
+        unsigned i = propertyName.toUInt32(isStrictUInt32);
+        if (isStrictUInt32 && i < m_length) {
+            slot.setValue(getIndex(exec, i));
+            return true;
+        }
+
+        return false;
+    }
+        
+    ALWAYS_INLINE bool JSString::getStringPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
+    {
+        if (propertyName < m_length) {
+            slot.setValue(getIndex(exec, propertyName));
+            return true;
+        }
+
+        return false;
+    }
+
+    inline bool isJSString(JSValue v) { return v.isCell() && v.asCell()->classInfo() == &JSString::s_info; }
+
+    inline bool JSCell::toBoolean(ExecState* exec) const
+    {
+        if (isString()) 
+            return static_cast<const JSString*>(this)->toBoolean(exec);
+        return !structure()->typeInfo().masqueradesAsUndefined();
+    }
+
+    // --- 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 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);
+    }
+
+} // namespace JSC
+
+#endif // JSString_h