1 files changed, 430 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/runtime/JSString.cpp b/Source/JavaScriptCore/runtime/JSString.cpp
new file mode 100644
index 000000000..eb046ed2d
--- /dev/null
+++ b/Source/JavaScriptCore/runtime/JSString.cpp
@@ -0,0 +1,430 @@
+/*
+ *  Copyright (C) 1999-2002 Harri Porten (porten@kde.org)
+ *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
+ *  Copyright (C) 2004, 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.
+ *
+ */
+
+#include "config.h"
+#include "JSString.h"
+
+#include "JSGlobalObject.h"
+#include "JSGlobalObjectFunctions.h"
+#include "JSObject.h"
+#include "JSCInlines.h"
+#include "StringObject.h"
+#include "StringPrototype.h"
+#include "StrongInlines.h"
+
+namespace JSC {
+    
+const ClassInfo JSString::s_info = { "string", 0, 0, CREATE_METHOD_TABLE(JSString) };
+
+void JSRopeString::RopeBuilder::expand()
+{
+    ASSERT(m_index == JSRopeString::s_maxInternalRopeLength);
+    JSString* jsString = m_jsString;
+    RELEASE_ASSERT(jsString);
+    m_jsString = jsStringBuilder(&m_vm);
+    m_index = 0;
+    append(jsString);
+}
+
+void JSString::destroy(JSCell* cell)
+{
+    JSString* thisObject = static_cast<JSString*>(cell);
+    thisObject->JSString::~JSString();
+}
+
+void JSString::dumpToStream(const JSCell* cell, PrintStream& out)
+{
+    const JSString* thisObject = jsCast<const JSString*>(cell);
+    out.printf("<%p, %s, [%u], ", thisObject, thisObject->className(), thisObject->length());
+    if (thisObject->isRope())
+        out.printf("[rope]");
+    else {
+        WTF::StringImpl* ourImpl = thisObject->m_value.impl();
+        if (ourImpl->is8Bit())
+            out.printf("[8 %p]", ourImpl->characters8());
+        else
+            out.printf("[16 %p]", ourImpl->characters16());
+    }
+    out.printf(">");
+}
+
+void JSString::visitChildren(JSCell* cell, SlotVisitor& visitor)
+{
+    JSString* thisObject = jsCast<JSString*>(cell);
+    Base::visitChildren(thisObject, visitor);
+    
+    if (thisObject->isRope())
+        static_cast<JSRopeString*>(thisObject)->visitFibers(visitor);
+    else {
+        StringImpl* impl = thisObject->m_value.impl();
+        ASSERT(impl);
+        visitor.reportExtraMemoryVisited(thisObject, impl->costDuringGC());
+    }
+}
+
+void JSRopeString::visitFibers(SlotVisitor& visitor)
+{
+    if (isSubstring()) {
+        visitor.append(&substringBase());
+        return;
+    }
+    for (size_t i = 0; i < s_maxInternalRopeLength && fiber(i); ++i)
+        visitor.append(&fiber(i));
+}
+
+static const unsigned maxLengthForOnStackResolve = 2048;
+
+void JSRopeString::resolveRopeInternal8(LChar* buffer) const
+{
+    if (isSubstring()) {
+        StringImpl::copyChars(
+            buffer, substringBase()->m_value.characters8() + substringOffset(), m_length);
+        return;
+    }
+    
+    resolveRopeInternal8NoSubstring(buffer);
+}
+
+void JSRopeString::resolveRopeInternal8NoSubstring(LChar* buffer) const
+{
+    for (size_t i = 0; i < s_maxInternalRopeLength && fiber(i); ++i) {
+        if (fiber(i)->isRope()) {
+            resolveRopeSlowCase8(buffer);
+            return;
+        }
+    }
+
+    LChar* position = buffer;
+    for (size_t i = 0; i < s_maxInternalRopeLength && fiber(i); ++i) {
+        const StringImpl& fiberString = *fiber(i)->m_value.impl();
+        unsigned length = fiberString.length();
+        StringImpl::copyChars(position, fiberString.characters8(), length);
+        position += length;
+    }
+    ASSERT((buffer + m_length) == position);
+}
+
+void JSRopeString::resolveRopeInternal16(UChar* buffer) const
+{
+    if (isSubstring()) {
+        StringImpl::copyChars(
+            buffer, substringBase()->m_value.characters16() + substringOffset(), m_length);
+        return;
+    }
+    
+    resolveRopeInternal16NoSubstring(buffer);
+}
+
+void JSRopeString::resolveRopeInternal16NoSubstring(UChar* buffer) const
+{
+    for (size_t i = 0; i < s_maxInternalRopeLength && fiber(i); ++i) {
+        if (fiber(i)->isRope()) {
+            resolveRopeSlowCase(buffer);
+            return;
+        }
+    }
+
+    UChar* position = buffer;
+    for (size_t i = 0; i < s_maxInternalRopeLength && fiber(i); ++i) {
+        const StringImpl& fiberString = *fiber(i)->m_value.impl();
+        unsigned length = fiberString.length();
+        if (fiberString.is8Bit())
+            StringImpl::copyChars(position, fiberString.characters8(), length);
+        else
+            StringImpl::copyChars(position, fiberString.characters16(), length);
+        position += length;
+    }
+    ASSERT((buffer + m_length) == position);
+}
+
+void JSRopeString::resolveRopeToAtomicString(ExecState* exec) const
+{
+    if (m_length > maxLengthForOnStackResolve) {
+        resolveRope(exec);
+        m_value = AtomicString(m_value);
+        setIs8Bit(m_value.impl()->is8Bit());
+        return;
+    }
+
+    if (is8Bit()) {
+        LChar buffer[maxLengthForOnStackResolve];
+        resolveRopeInternal8(buffer);
+        m_value = AtomicString(buffer, m_length);
+        setIs8Bit(m_value.impl()->is8Bit());
+    } else {
+        UChar buffer[maxLengthForOnStackResolve];
+        resolveRopeInternal16(buffer);
+        m_value = AtomicString(buffer, m_length);
+        setIs8Bit(m_value.impl()->is8Bit());
+    }
+
+    clearFibers();
+
+    // If we resolved a string that didn't previously exist, notify the heap that we've grown.
+    if (m_value.impl()->hasOneRef())
+        Heap::heap(this)->reportExtraMemoryAllocated(m_value.impl()->cost());
+}
+
+void JSRopeString::clearFibers() const
+{
+    for (size_t i = 0; i < s_maxInternalRopeLength; ++i)
+        u[i].number = 0;
+}
+
+RefPtr<AtomicStringImpl> JSRopeString::resolveRopeToExistingAtomicString(ExecState* exec) const
+{
+    if (m_length > maxLengthForOnStackResolve) {
+        resolveRope(exec);
+        if (RefPtr<AtomicStringImpl> existingAtomicString = AtomicStringImpl::lookUp(m_value.impl())) {
+            m_value = *existingAtomicString;
+            setIs8Bit(m_value.impl()->is8Bit());
+            clearFibers();
+            return existingAtomicString;
+        }
+        return nullptr;
+    }
+    
+    if (is8Bit()) {
+        LChar buffer[maxLengthForOnStackResolve];
+        resolveRopeInternal8(buffer);
+        if (RefPtr<AtomicStringImpl> existingAtomicString = AtomicStringImpl::lookUp(buffer, m_length)) {
+            m_value = *existingAtomicString;
+            setIs8Bit(m_value.impl()->is8Bit());
+            clearFibers();
+            return existingAtomicString;
+        }
+    } else {
+        UChar buffer[maxLengthForOnStackResolve];
+        resolveRopeInternal16(buffer);
+        if (RefPtr<AtomicStringImpl> existingAtomicString = AtomicStringImpl::lookUp(buffer, m_length)) {
+            m_value = *existingAtomicString;
+            setIs8Bit(m_value.impl()->is8Bit());
+            clearFibers();
+            return existingAtomicString;
+        }
+    }
+
+    return nullptr;
+}
+
+void JSRopeString::resolveRope(ExecState* exec) const
+{
+    ASSERT(isRope());
+    
+    if (isSubstring()) {
+        ASSERT(!substringBase()->isRope());
+        m_value = substringBase()->m_value.substring(substringOffset(), m_length);
+        substringBase().clear();
+        return;
+    }
+    
+    if (is8Bit()) {
+        LChar* buffer;
+        if (RefPtr<StringImpl> newImpl = StringImpl::tryCreateUninitialized(m_length, buffer)) {
+            Heap::heap(this)->reportExtraMemoryAllocated(newImpl->cost());
+            m_value = newImpl.release();
+        } else {
+            outOfMemory(exec);
+            return;
+        }
+        resolveRopeInternal8NoSubstring(buffer);
+        clearFibers();
+        ASSERT(!isRope());
+        return;
+    }
+
+    UChar* buffer;
+    if (RefPtr<StringImpl> newImpl = StringImpl::tryCreateUninitialized(m_length, buffer)) {
+        Heap::heap(this)->reportExtraMemoryAllocated(newImpl->cost());
+        m_value = newImpl.release();
+    } else {
+        outOfMemory(exec);
+        return;
+    }
+
+    resolveRopeInternal16NoSubstring(buffer);
+    clearFibers();
+    ASSERT(!isRope());
+}
+
+// Overview: These functions convert a JSString from holding a string in rope form
+// down to a simple String representation. It does so by building up the string
+// backwards, since we want to avoid recursion, we expect that the tree structure
+// representing the rope is likely imbalanced with more nodes down the left side
+// (since appending to the string is likely more common) - and as such resolving
+// in this fashion should minimize work queue size.  (If we built the queue forwards
+// we would likely have to place all of the constituent StringImpls into the
+// Vector before performing any concatenation, but by working backwards we likely
+// only fill the queue with the number of substrings at any given level in a
+// rope-of-ropes.)    
+void JSRopeString::resolveRopeSlowCase8(LChar* buffer) const
+{
+    LChar* position = buffer + m_length; // We will be working backwards over the rope.
+    Vector<JSString*, 32, UnsafeVectorOverflow> workQueue; // Putting strings into a Vector is only OK because there are no GC points in this method.
+    
+    for (size_t i = 0; i < s_maxInternalRopeLength && fiber(i); ++i)
+        workQueue.append(fiber(i).get());
+
+    while (!workQueue.isEmpty()) {
+        JSString* currentFiber = workQueue.last();
+        workQueue.removeLast();
+
+        const LChar* characters;
+        
+        if (currentFiber->isRope()) {
+            JSRopeString* currentFiberAsRope = static_cast<JSRopeString*>(currentFiber);
+            if (!currentFiberAsRope->isSubstring()) {
+                for (size_t i = 0; i < s_maxInternalRopeLength && currentFiberAsRope->fiber(i); ++i)
+                    workQueue.append(currentFiberAsRope->fiber(i).get());
+                continue;
+            }
+            ASSERT(!currentFiberAsRope->substringBase()->isRope());
+            characters =
+                currentFiberAsRope->substringBase()->m_value.characters8() +
+                currentFiberAsRope->substringOffset();
+        } else
+            characters = currentFiber->m_value.characters8();
+        
+        unsigned length = currentFiber->length();
+        position -= length;
+        StringImpl::copyChars(position, characters, length);
+    }
+
+    ASSERT(buffer == position);
+}
+
+void JSRopeString::resolveRopeSlowCase(UChar* buffer) const
+{
+    UChar* position = buffer + m_length; // We will be working backwards over the rope.
+    Vector<JSString*, 32, UnsafeVectorOverflow> workQueue; // These strings are kept alive by the parent rope, so using a Vector is OK.
+
+    for (size_t i = 0; i < s_maxInternalRopeLength && fiber(i); ++i)
+        workQueue.append(fiber(i).get());
+
+    while (!workQueue.isEmpty()) {
+        JSString* currentFiber = workQueue.last();
+        workQueue.removeLast();
+
+        if (currentFiber->isRope()) {
+            JSRopeString* currentFiberAsRope = static_cast<JSRopeString*>(currentFiber);
+            if (currentFiberAsRope->isSubstring()) {
+                ASSERT(!currentFiberAsRope->substringBase()->isRope());
+                StringImpl* string = static_cast<StringImpl*>(
+                    currentFiberAsRope->substringBase()->m_value.impl());
+                unsigned offset = currentFiberAsRope->substringOffset();
+                unsigned length = currentFiberAsRope->length();
+                position -= length;
+                if (string->is8Bit())
+                    StringImpl::copyChars(position, string->characters8() + offset, length);
+                else
+                    StringImpl::copyChars(position, string->characters16() + offset, length);
+                continue;
+            }
+            for (size_t i = 0; i < s_maxInternalRopeLength && currentFiberAsRope->fiber(i); ++i)
+                workQueue.append(currentFiberAsRope->fiber(i).get());
+            continue;
+        }
+
+        StringImpl* string = static_cast<StringImpl*>(currentFiber->m_value.impl());
+        unsigned length = string->length();
+        position -= length;
+        if (string->is8Bit())
+            StringImpl::copyChars(position, string->characters8(), length);
+        else
+            StringImpl::copyChars(position, string->characters16(), length);
+    }
+
+    ASSERT(buffer == position);
+}
+
+void JSRopeString::outOfMemory(ExecState* exec) const
+{
+    clearFibers();
+    ASSERT(isRope());
+    ASSERT(m_value.isNull());
+    if (exec)
+        throwOutOfMemoryError(exec);
+}
+
+JSValue JSString::toPrimitive(ExecState*, PreferredPrimitiveType) const
+{
+    return const_cast<JSString*>(this);
+}
+
+bool JSString::getPrimitiveNumber(ExecState* exec, double& number, JSValue& result) const
+{
+    result = this;
+    number = jsToNumber(view(exec));
+    return false;
+}
+
+double JSString::toNumber(ExecState* exec) const
+{
+    return jsToNumber(view(exec));
+}
+
+inline StringObject* StringObject::create(VM& vm, JSGlobalObject* globalObject, JSString* string)
+{
+    StringObject* object = new (NotNull, allocateCell<StringObject>(vm.heap)) StringObject(vm, globalObject->stringObjectStructure());
+    object->finishCreation(vm, string);
+    return object;
+}
+
+JSObject* JSString::toObject(ExecState* exec, JSGlobalObject* globalObject) const
+{
+    return StringObject::create(exec->vm(), globalObject, const_cast<JSString*>(this));
+}
+
+JSValue JSString::toThis(JSCell* cell, ExecState* exec, ECMAMode ecmaMode)
+{
+    if (ecmaMode == StrictMode)
+        return cell;
+    return StringObject::create(exec->vm(), exec->lexicalGlobalObject(), jsCast<JSString*>(cell));
+}
+
+bool JSString::getStringPropertyDescriptor(ExecState* exec, PropertyName propertyName, PropertyDescriptor& descriptor)
+{
+    if (propertyName == exec->propertyNames().length) {
+        descriptor.setDescriptor(jsNumber(m_length), DontEnum | DontDelete | ReadOnly);
+        return true;
+    }
+    
+    Optional<uint32_t> index = parseIndex(propertyName);
+    if (index && index.value() < m_length) {
+        descriptor.setDescriptor(getIndex(exec, index.value()), DontDelete | ReadOnly);
+        return true;
+    }
+    
+    return false;
+}
+
+JSString* jsStringWithCacheSlowCase(VM& vm, StringImpl& stringImpl)
+{
+    if (JSString* string = vm.stringCache.get(&stringImpl))
+        return string;
+
+    JSString* string = jsString(&vm, String(stringImpl));
+    vm.lastCachedString.set(vm, string);
+    return string;
+}
+
+} // namespace JSC