/* * Copyright (C) 1999-2002 Harri Porten ([email protected]) * Copyright (C) 2001 Peter Kelly ([email protected]) * 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 "JSObject.h" #include "Operations.h" #include "StringObject.h" #include "StringPrototype.h" namespace JSC { static const unsigned resolveRopeForSubstringCutoff = 4; // 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 UStringImpls 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::resolveRope(ExecState* exec) const { ASSERT(isRope()); // Allocate the buffer to hold the final string, position initially points to the end. UChar* buffer; if (PassRefPtr newImpl = UStringImpl::tryCreateUninitialized(m_length, buffer)) m_value = newImpl; else { for (unsigned i = 0; i workQueue; RopeImpl::Fiber currentFiber; for (unsigned i = 0; i (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 fibers()[i]); currentFiber = rope->fibers()[fiberCountMinusOne]; } else { UStringImpl* string = static_cast(currentFiber); unsigned length = string->length(); position -= length; UStringImpl::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 globalData(); UString substringFibers[3]; unsigned fiberCount = 0; unsigned substringFiberCount = 0; unsigned substringEnd = substringStart + substringLength; unsigned fiberEnd = 0; RopeIterator end; for (RopeIterator it(m_other.m_fibers, m_fiberCount); it != end; ++it) { ++fiberCount; UStringImpl* fiberString = *it; unsigned fiberStart = fiberEnd; fiberEnd = fiberStart + fiberString->length(); if (fiberEnd = substringEnd) break; if (fiberCount > resolveRopeForSubstringCutoff || 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 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]); } JSValue JSString::replaceCharacter(ExecState* exec, UChar character, const UString& replacement) { if (!isRope()) { unsigned matchPosition = m_value.find(character); if (matchPosition == UString::NotFound) return JSValue(this); return jsString(exec, m_value.substr(0, matchPosition), replacement, m_value.substr(matchPosition + 1)); } RopeIterator end; // Count total fibers and find matching string. size_t fiberCount = 0; UStringImpl* matchString = 0; int matchPosition = -1; for (RopeIterator it(m_other.m_fibers, m_fiberCount); it != end; ++it) { ++fiberCount; if (matchString) continue; UStringImpl* string = *it; matchPosition = string->find(character); if (matchPosition == -1) continue; matchString = string; } if (!matchString) return this; RopeBuilder builder(replacement.size() ? fiberCount + 2 : fiberCount + 1); if (UNLIKELY(builder.isOutOfMemory())) return throwOutOfMemoryError(exec); for (RopeIterator it(m_other.m_fibers, m_fiberCount); it != end; ++it) { UStringImpl* string = *it; if (string != matchString) { builder.append(UString(string)); continue; } builder.append(UString(string).substr(0, matchPosition)); if (replacement.size()) builder.append(replacement); builder.append(UString(string).substr(matchPosition + 1)); matchString = 0; } JSGlobalData* globalData = &exec->globalData(); return JSValue(new (globalData) JSString(globalData, builder.release())); } JSString* JSString::getIndexSlowCase(ExecState* exec, unsigned i) { 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 (this); } bool JSString::getPrimitiveNumber(ExecState* exec, double& number, JSValue& result) { result = this; number = value(exec).toDouble(); return false; } bool JSString::toBoolean(ExecState*) const { return m_length; } double JSString::toNumber(ExecState* exec) const { return value(exec).toDouble(); } UString JSString::toString(ExecState* exec) const { return value(exec); } inline StringObject* StringObject::create(ExecState* exec, JSString* string) { return new (exec) StringObject(exec->lexicalGlobalObject()->stringObjectStructure(), string); } JSObject* JSString::toObject(ExecState* exec) const { return StringObject::create(exec, const_cast(this)); } JSObject* JSString::toThisObject(ExecState* exec) const { return StringObject::create(exec, const_cast(this)); } bool JSString::getOwnPropertySlot(ExecState* exec, const Identifier& 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; if (propertyName == exec->propertyNames().underscoreProto) { slot.setValue(exec->lexicalGlobalObject()->stringPrototype()); return true; } slot.setBase(this); JSObject* object; for (JSValue prototype = exec->lexicalGlobalObject()->stringPrototype(); !prototype.isNull(); prototype = object->prototype()) { object = asObject(prototype); if (object->getOwnPropertySlot(exec, propertyName, slot)) return true; } slot.setUndefined(); return true; } bool JSString::getStringPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor) { if (propertyName == exec->propertyNames().length) { descriptor.setDescriptor(jsNumber(exec, m_length), DontEnum | DontDelete | ReadOnly); return true; } bool isStrictUInt32; unsigned i = propertyName.toStrictUInt32(&isStrictUInt32); if (isStrictUInt32 && i 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