2 * Copyright (C) 1999-2002 Harri Porten (porten@kde.org)
3 * Copyright (C) 2001 Peter Kelly (pmk@post.com)
4 * Copyright (C) 2004, 2007, 2008 Apple Inc. All rights reserved.
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public License
17 * along with this library; see the file COPYING.LIB. If not, write to
18 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
26 #include "JSGlobalObject.h"
27 #include "JSGlobalObjectFunctions.h"
29 #include "Operations.h"
30 #include "StringObject.h"
31 #include "StringPrototype.h"
35 static const unsigned substringFromRopeCutoff = 4;
37 const ClassInfo JSString::s_info = { "string", 0, 0, 0 };
39 void JSString::resolveRope(ExecState* exec) const
44 if (PassRefPtr<StringImpl> newImpl = StringImpl::tryCreateUninitialized(m_length, buffer))
51 RopeImpl::Fiber currentFiber = m_fibers[0];
53 if ((m_fiberCount > 2) || (RopeImpl::isRope(currentFiber))
54 || ((m_fiberCount == 2) && (RopeImpl::isRope(m_fibers[1])))) {
55 resolveRopeSlowCase(exec, buffer);
59 UChar* position = buffer;
60 StringImpl* string = static_cast<StringImpl*>(currentFiber);
61 unsigned length = string->length();
62 StringImpl::copyChars(position, string->characters(), length);
64 if (m_fiberCount > 1) {
66 currentFiber = m_fibers[1];
67 string = static_cast<StringImpl*>(currentFiber);
68 length = string->length();
69 StringImpl::copyChars(position, string->characters(), length);
73 ASSERT((buffer + m_length) == position);
74 for (unsigned i = 0; i < m_fiberCount; ++i) {
75 RopeImpl::deref(m_fibers[i]);
83 // Overview: this methods converts a JSString from holding a string in rope form
84 // down to a simple UString representation. It does so by building up the string
85 // backwards, since we want to avoid recursion, we expect that the tree structure
86 // representing the rope is likely imbalanced with more nodes down the left side
87 // (since appending to the string is likely more common) - and as such resolving
88 // in this fashion should minimize work queue size. (If we built the queue forwards
89 // we would likely have to place all of the constituent StringImpls into the
90 // Vector before performing any concatenation, but by working backwards we likely
91 // only fill the queue with the number of substrings at any given level in a
93 void JSString::resolveRopeSlowCase(ExecState* exec, UChar* buffer) const
97 UChar* position = buffer + m_length;
99 // Start with the current RopeImpl.
100 Vector<RopeImpl::Fiber, 32> workQueue;
101 RopeImpl::Fiber currentFiber;
102 for (unsigned i = 0; i < (m_fiberCount - 1); ++i)
103 workQueue.append(m_fibers[i]);
104 currentFiber = m_fibers[m_fiberCount - 1];
106 if (RopeImpl::isRope(currentFiber)) {
107 RopeImpl* rope = static_cast<RopeImpl*>(currentFiber);
108 // Copy the contents of the current rope into the workQueue, with the last item in 'currentFiber'
109 // (we will be working backwards over the rope).
110 unsigned fiberCountMinusOne = rope->fiberCount() - 1;
111 for (unsigned i = 0; i < fiberCountMinusOne; ++i)
112 workQueue.append(rope->fibers()[i]);
113 currentFiber = rope->fibers()[fiberCountMinusOne];
115 StringImpl* string = static_cast<StringImpl*>(currentFiber);
116 unsigned length = string->length();
118 StringImpl::copyChars(position, string->characters(), length);
120 // Was this the last item in the work queue?
121 if (workQueue.isEmpty()) {
122 // Create a string from the UChar buffer, clear the rope RefPtr.
123 ASSERT(buffer == position);
124 for (unsigned i = 0; i < m_fiberCount; ++i) {
125 RopeImpl::deref(m_fibers[i]);
134 // No! - set the next item up to process.
135 currentFiber = workQueue.last();
136 workQueue.removeLast();
141 void JSString::outOfMemory(ExecState* exec) const
143 for (unsigned i = 0; i < m_fiberCount; ++i) {
144 RopeImpl::deref(m_fibers[i]);
149 ASSERT(m_value == UString());
151 throwOutOfMemoryError(exec);
154 // This function construsts a substring out of a rope without flattening by reusing the existing fibers.
155 // This can reduce memory usage substantially. Since traversing ropes is slow the function will revert
156 // back to flattening if the rope turns out to be long.
157 JSString* JSString::substringFromRope(ExecState* exec, unsigned substringStart, unsigned substringLength)
160 ASSERT(substringLength);
162 JSGlobalData* globalData = &exec->globalData();
164 UString substringFibers[3];
166 unsigned fiberCount = 0;
167 unsigned substringFiberCount = 0;
168 unsigned substringEnd = substringStart + substringLength;
169 unsigned fiberEnd = 0;
172 for (RopeIterator it(m_fibers.data(), m_fiberCount); it != end; ++it) {
174 StringImpl* fiberString = *it;
175 unsigned fiberStart = fiberEnd;
176 fiberEnd = fiberStart + fiberString->length();
177 if (fiberEnd <= substringStart)
179 unsigned copyStart = std::max(substringStart, fiberStart);
180 unsigned copyEnd = std::min(substringEnd, fiberEnd);
181 if (copyStart == fiberStart && copyEnd == fiberEnd)
182 substringFibers[substringFiberCount++] = UString(fiberString);
184 substringFibers[substringFiberCount++] = UString(StringImpl::create(fiberString, copyStart - fiberStart, copyEnd - copyStart));
185 if (fiberEnd >= substringEnd)
187 if (fiberCount > substringFromRopeCutoff || substringFiberCount >= 3) {
188 // This turned out to be a really inefficient rope. Just flatten it.
190 return jsSubstring(&exec->globalData(), m_value, substringStart, substringLength);
193 ASSERT(substringFiberCount && substringFiberCount <= 3);
195 if (substringLength == 1) {
196 ASSERT(substringFiberCount == 1);
197 UChar c = substringFibers[0][0];
198 if (c <= maxSingleCharacterString)
199 return globalData->smallStrings.singleCharacterString(globalData, c);
201 if (substringFiberCount == 1)
202 return JSString::create(*globalData, substringFibers[0]);
203 if (substringFiberCount == 2)
204 return JSString::create(*globalData, substringFibers[0], substringFibers[1]);
205 return JSString::create(*globalData, substringFibers[0], substringFibers[1], substringFibers[2]);
208 JSValue JSString::replaceCharacter(ExecState* exec, UChar character, const UString& replacement)
211 size_t matchPosition = m_value.find(character);
212 if (matchPosition == notFound)
213 return JSValue(this);
214 return jsString(exec, m_value.substringSharingImpl(0, matchPosition), replacement, m_value.substringSharingImpl(matchPosition + 1));
219 // Count total fibers and find matching string.
220 size_t fiberCount = 0;
221 StringImpl* matchString = 0;
222 size_t matchPosition = notFound;
223 for (RopeIterator it(m_fibers.data(), m_fiberCount); it != end; ++it) {
228 StringImpl* string = *it;
229 matchPosition = string->find(character);
230 if (matchPosition == notFound)
232 matchString = string;
238 RopeBuilder builder(replacement.length() ? fiberCount + 2 : fiberCount + 1);
239 if (UNLIKELY(builder.isOutOfMemory()))
240 return throwOutOfMemoryError(exec);
242 for (RopeIterator it(m_fibers.data(), m_fiberCount); it != end; ++it) {
243 StringImpl* string = *it;
244 if (string != matchString) {
245 builder.append(UString(string));
249 builder.append(UString(string).substringSharingImpl(0, matchPosition));
250 if (replacement.length())
251 builder.append(replacement);
252 builder.append(UString(string).substringSharingImpl(matchPosition + 1));
256 JSGlobalData* globalData = &exec->globalData();
257 return JSValue(JSString::create(*globalData, builder.release()));
260 JSString* JSString::getIndexSlowCase(ExecState* exec, unsigned i)
264 // Return a safe no-value result, this should never be used, since the excetion will be thrown.
265 if (exec->exception())
266 return jsString(exec, "");
268 ASSERT(i < m_value.length());
269 return jsSingleCharacterSubstring(exec, m_value, i);
272 JSValue JSString::toPrimitive(ExecState*, PreferredPrimitiveType) const
274 return const_cast<JSString*>(this);
277 bool JSString::getPrimitiveNumber(ExecState* exec, double& number, JSValue& result)
280 number = jsToNumber(value(exec));
284 bool JSString::toBoolean(ExecState*) const
289 double JSString::toNumber(ExecState* exec) const
291 return jsToNumber(value(exec));
294 UString JSString::toString(ExecState* exec) const
299 inline StringObject* StringObject::create(ExecState* exec, JSGlobalObject* globalObject, JSString* string)
301 StringObject* object = new (allocateCell<StringObject>(*exec->heap())) StringObject(exec->globalData(), globalObject->stringObjectStructure());
302 object->finishCreation(exec->globalData(), string);
306 JSObject* JSString::toObject(ExecState* exec, JSGlobalObject* globalObject) const
308 return StringObject::create(exec, globalObject, const_cast<JSString*>(this));
311 JSObject* JSString::toThisObject(ExecState* exec) const
313 return StringObject::create(exec, exec->lexicalGlobalObject(), const_cast<JSString*>(this));
316 bool JSString::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
318 // The semantics here are really getPropertySlot, not getOwnPropertySlot.
319 // This function should only be called by JSValue::get.
320 if (getStringPropertySlot(exec, propertyName, slot))
322 if (propertyName == exec->propertyNames().underscoreProto) {
323 slot.setValue(exec->lexicalGlobalObject()->stringPrototype());
328 for (JSValue prototype = exec->lexicalGlobalObject()->stringPrototype(); !prototype.isNull(); prototype = object->prototype()) {
329 object = asObject(prototype);
330 if (object->getOwnPropertySlot(exec, propertyName, slot))
337 bool JSString::getStringPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor)
339 if (propertyName == exec->propertyNames().length) {
340 descriptor.setDescriptor(jsNumber(m_length), DontEnum | DontDelete | ReadOnly);
345 unsigned i = propertyName.toUInt32(isStrictUInt32);
346 if (isStrictUInt32 && i < m_length) {
347 descriptor.setDescriptor(getIndex(exec, i), DontDelete | ReadOnly);
354 bool JSString::getOwnPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor)
356 if (getStringPropertyDescriptor(exec, propertyName, descriptor))
358 if (propertyName != exec->propertyNames().underscoreProto)
360 descriptor.setDescriptor(exec->lexicalGlobalObject()->stringPrototype(), DontEnum);
364 bool JSString::getOwnPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
366 // The semantics here are really getPropertySlot, not getOwnPropertySlot.
367 // This function should only be called by JSValue::get.
368 if (getStringPropertySlot(exec, propertyName, slot))
370 return JSString::getOwnPropertySlot(exec, Identifier::from(exec, propertyName), slot);