#include "JSString.h"
#include "JSGlobalObject.h"
+#include "JSGlobalObjectFunctions.h"
#include "JSObject.h"
+#include "Operations.h"
#include "StringObject.h"
#include "StringPrototype.h"
namespace JSC {
+
+static const unsigned substringFromRopeCutoff = 4;
-JSValue JSString::toPrimitive(ExecState*, PreferredPrimitiveType) const
+const ClassInfo JSString::s_info = { "string", 0, 0, 0 };
+
+void JSString::resolveRope(ExecState* exec) const
{
- return const_cast<JSString*>(this);
+ ASSERT(isRope());
+
+ UChar* buffer;
+ if (PassRefPtr<StringImpl> newImpl = StringImpl::tryCreateUninitialized(m_length, buffer))
+ m_value = newImpl;
+ else {
+ outOfMemory(exec);
+ return;
+ }
+
+ RopeImpl::Fiber currentFiber = m_fibers[0];
+
+ if ((m_fiberCount > 2) || (RopeImpl::isRope(currentFiber))
+ || ((m_fiberCount == 2) && (RopeImpl::isRope(m_fibers[1])))) {
+ resolveRopeSlowCase(exec, buffer);
+ return;
+ }
+
+ UChar* position = buffer;
+ StringImpl* string = static_cast<StringImpl*>(currentFiber);
+ unsigned length = string->length();
+ StringImpl::copyChars(position, string->characters(), length);
+
+ if (m_fiberCount > 1) {
+ position += length;
+ currentFiber = m_fibers[1];
+ string = static_cast<StringImpl*>(currentFiber);
+ length = string->length();
+ StringImpl::copyChars(position, string->characters(), length);
+ position += length;
+ }
+
+ ASSERT((buffer + m_length) == position);
+ for (unsigned i = 0; i < m_fiberCount; ++i) {
+ RopeImpl::deref(m_fibers[i]);
+ m_fibers[i] = 0;
+ }
+ m_fiberCount = 0;
+
+ ASSERT(!isRope());
}
-bool JSString::getPrimitiveNumber(ExecState*, double& number, JSValue& value)
+// Overview: this methods converts a JSString from holding a string in rope form
+// down to a simple UString 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 JSString::resolveRopeSlowCase(ExecState* exec, UChar* buffer) const
{
- value = this;
- number = m_value.toDouble();
- return false;
+ UNUSED_PARAM(exec);
+
+ UChar* position = buffer + m_length;
+
+ // Start with the current RopeImpl.
+ Vector<RopeImpl::Fiber, 32> workQueue;
+ RopeImpl::Fiber currentFiber;
+ for (unsigned i = 0; i < (m_fiberCount - 1); ++i)
+ workQueue.append(m_fibers[i]);
+ currentFiber = m_fibers[m_fiberCount - 1];
+ while (true) {
+ if (RopeImpl::isRope(currentFiber)) {
+ RopeImpl* rope = static_cast<RopeImpl*>(currentFiber);
+ // Copy the contents of the current rope into the workQueue, with the last item in 'currentFiber'
+ // (we will be working backwards over the rope).
+ unsigned fiberCountMinusOne = rope->fiberCount() - 1;
+ for (unsigned i = 0; i < fiberCountMinusOne; ++i)
+ workQueue.append(rope->fibers()[i]);
+ currentFiber = rope->fibers()[fiberCountMinusOne];
+ } else {
+ StringImpl* string = static_cast<StringImpl*>(currentFiber);
+ unsigned length = string->length();
+ position -= length;
+ StringImpl::copyChars(position, string->characters(), length);
+
+ // Was this the last item in the work queue?
+ if (workQueue.isEmpty()) {
+ // Create a string from the UChar buffer, clear the rope RefPtr.
+ ASSERT(buffer == position);
+ for (unsigned i = 0; i < m_fiberCount; ++i) {
+ RopeImpl::deref(m_fibers[i]);
+ m_fibers[i] = 0;
+ }
+ m_fiberCount = 0;
+
+ ASSERT(!isRope());
+ return;
+ }
+
+ // No! - set the next item up to process.
+ currentFiber = workQueue.last();
+ workQueue.removeLast();
+ }
+ }
}
-bool JSString::toBoolean(ExecState*) const
+void JSString::outOfMemory(ExecState* exec) const
{
- return !m_value.isEmpty();
+ for (unsigned i = 0; i < m_fiberCount; ++i) {
+ RopeImpl::deref(m_fibers[i]);
+ m_fibers[i] = 0;
+ }
+ m_fiberCount = 0;
+ ASSERT(!isRope());
+ ASSERT(m_value == UString());
+ if (exec)
+ throwOutOfMemoryError(exec);
}
-double JSString::toNumber(ExecState*) const
+// This function construsts a substring out of a rope without flattening by reusing the existing fibers.
+// This can reduce memory usage substantially. Since traversing ropes is slow the function will revert
+// back to flattening if the rope turns out to be long.
+JSString* JSString::substringFromRope(ExecState* exec, unsigned substringStart, unsigned substringLength)
{
- return m_value.toDouble();
+ ASSERT(isRope());
+ ASSERT(substringLength);
+
+ JSGlobalData* globalData = &exec->globalData();
+
+ UString substringFibers[3];
+
+ unsigned fiberCount = 0;
+ unsigned substringFiberCount = 0;
+ unsigned substringEnd = substringStart + substringLength;
+ unsigned fiberEnd = 0;
+
+ RopeIterator end;
+ for (RopeIterator it(m_fibers.data(), m_fiberCount); it != end; ++it) {
+ ++fiberCount;
+ StringImpl* fiberString = *it;
+ unsigned fiberStart = fiberEnd;
+ fiberEnd = fiberStart + fiberString->length();
+ if (fiberEnd <= substringStart)
+ continue;
+ unsigned copyStart = std::max(substringStart, fiberStart);
+ unsigned copyEnd = std::min(substringEnd, fiberEnd);
+ if (copyStart == fiberStart && copyEnd == fiberEnd)
+ substringFibers[substringFiberCount++] = UString(fiberString);
+ else
+ substringFibers[substringFiberCount++] = UString(StringImpl::create(fiberString, copyStart - fiberStart, copyEnd - copyStart));
+ if (fiberEnd >= substringEnd)
+ break;
+ if (fiberCount > substringFromRopeCutoff || substringFiberCount >= 3) {
+ // This turned out to be a really inefficient rope. Just flatten it.
+ resolveRope(exec);
+ return jsSubstring(&exec->globalData(), m_value, substringStart, substringLength);
+ }
+ }
+ ASSERT(substringFiberCount && substringFiberCount <= 3);
+
+ if (substringLength == 1) {
+ ASSERT(substringFiberCount == 1);
+ UChar c = substringFibers[0].characters()[0];
+ if (c <= maxSingleCharacterString)
+ return globalData->smallStrings.singleCharacterString(globalData, c);
+ }
+ if (substringFiberCount == 1)
+ return new (globalData) JSString(globalData, substringFibers[0]);
+ if (substringFiberCount == 2)
+ return new (globalData) JSString(globalData, substringFibers[0], substringFibers[1]);
+ return new (globalData) JSString(globalData, substringFibers[0], substringFibers[1], substringFibers[2]);
}
-UString JSString::toString(ExecState*) const
+JSValue JSString::replaceCharacter(ExecState* exec, UChar character, const UString& replacement)
{
- return m_value;
+ if (!isRope()) {
+ size_t matchPosition = m_value.find(character);
+ if (matchPosition == notFound)
+ return JSValue(this);
+ return jsString(exec, m_value.substringSharingImpl(0, matchPosition), replacement, m_value.substringSharingImpl(matchPosition + 1));
+ }
+
+ RopeIterator end;
+
+ // Count total fibers and find matching string.
+ size_t fiberCount = 0;
+ StringImpl* matchString = 0;
+ size_t matchPosition = notFound;
+ for (RopeIterator it(m_fibers.data(), m_fiberCount); it != end; ++it) {
+ ++fiberCount;
+ if (matchString)
+ continue;
+
+ StringImpl* string = *it;
+ matchPosition = string->find(character);
+ if (matchPosition == notFound)
+ continue;
+ matchString = string;
+ }
+
+ if (!matchString)
+ return this;
+
+ RopeBuilder builder(replacement.length() ? fiberCount + 2 : fiberCount + 1);
+ if (UNLIKELY(builder.isOutOfMemory()))
+ return throwOutOfMemoryError(exec);
+
+ for (RopeIterator it(m_fibers.data(), m_fiberCount); it != end; ++it) {
+ StringImpl* string = *it;
+ if (string != matchString) {
+ builder.append(UString(string));
+ continue;
+ }
+
+ builder.append(UString(string).substringSharingImpl(0, matchPosition));
+ if (replacement.length())
+ builder.append(replacement);
+ builder.append(UString(string).substringSharingImpl(matchPosition + 1));
+ matchString = 0;
+ }
+
+ JSGlobalData* globalData = &exec->globalData();
+ return JSValue(new (globalData) JSString(globalData, builder.release()));
}
-UString JSString::toThisString(ExecState*) const
+JSString* JSString::getIndexSlowCase(ExecState* exec, unsigned i)
{
- return m_value;
+ ASSERT(isRope());
+ resolveRope(exec);
+ // Return a safe no-value result, this should never be used, since the excetion will be thrown.
+ if (exec->exception())
+ return jsString(exec, "");
+ ASSERT(!isRope());
+ ASSERT(i < m_value.length());
+ return jsSingleCharacterSubstring(exec, m_value, i);
}
-JSString* JSString::toThisJSString(ExecState*)
+JSValue JSString::toPrimitive(ExecState*, PreferredPrimitiveType) const
{
- return this;
+ return const_cast<JSString*>(this);
+}
+
+bool JSString::getPrimitiveNumber(ExecState* exec, double& number, JSValue& result)
+{
+ result = this;
+ number = jsToNumber(value(exec));
+ return false;
}
-inline StringObject* StringObject::create(ExecState* exec, JSString* string)
+bool JSString::toBoolean(ExecState*) const
{
- return new (exec) StringObject(exec->lexicalGlobalObject()->stringObjectStructure(), string);
+ return m_length;
}
-JSObject* JSString::toObject(ExecState* exec) const
+double JSString::toNumber(ExecState* exec) const
{
- return StringObject::create(exec, const_cast<JSString*>(this));
+ return jsToNumber(value(exec));
+}
+
+UString JSString::toString(ExecState* exec) const
+{
+ return value(exec);
+}
+
+inline StringObject* StringObject::create(ExecState* exec, JSGlobalObject* globalObject, JSString* string)
+{
+ return new (exec) StringObject(exec->globalData(), globalObject->stringObjectStructure(), string);
+}
+
+JSObject* JSString::toObject(ExecState* exec, JSGlobalObject* globalObject) const
+{
+ return StringObject::create(exec, globalObject, const_cast<JSString*>(this));
}
JSObject* JSString::toThisObject(ExecState* exec) const
{
- return StringObject::create(exec, const_cast<JSString*>(this));
+ return StringObject::create(exec, exec->lexicalGlobalObject(), const_cast<JSString*>(this));
}
bool JSString::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
return true;
}
-bool JSString::getOwnPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
+bool JSString::getStringPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor)
{
- // The semantics here are really getPropertySlot, not getOwnPropertySlot.
- // This function should only be called by JSValue::get.
- if (getStringPropertySlot(exec, propertyName, slot))
+ if (propertyName == exec->propertyNames().length) {
+ descriptor.setDescriptor(jsNumber(m_length), DontEnum | DontDelete | ReadOnly);
return true;
- return JSString::getOwnPropertySlot(exec, Identifier::from(exec, propertyName), slot);
-}
-
-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);
-}
-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);
+ bool isStrictUInt32;
+ unsigned i = propertyName.toUInt32(isStrictUInt32);
+ if (isStrictUInt32 && i < m_length) {
+ descriptor.setDescriptor(getIndex(exec, i), DontDelete | ReadOnly);
+ return true;
}
- return new (globalData) JSString(globalData, UString::Rep::create(s.rep(), offset, length));
+
+ return false;
}
-JSString* jsOwnedString(JSGlobalData* globalData, const UString& s)
+bool JSString::getOwnPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor)
{
- 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);
+ if (getStringPropertyDescriptor(exec, propertyName, descriptor))
+ return true;
+ if (propertyName != exec->propertyNames().underscoreProto)
+ return false;
+ descriptor.setDescriptor(exec->lexicalGlobalObject()->stringPrototype(), DontEnum);
+ return true;
+}
+
+bool JSString::getOwnPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
+{
+ // The semantics here are really getPropertySlot, not getOwnPropertySlot.
+ // This function should only be called by JSValue::get.
+ if (getStringPropertySlot(exec, propertyName, slot))
+ return true;
+ return JSString::getOwnPropertySlot(exec, Identifier::from(exec, propertyName), slot);
}
} // namespace JSC
projects / apple / javascriptcore.git / blobdiff