1 /*
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.
5 *
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.
10 *
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.
15 *
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.
20 *
21 */
22
23 #include "config.h"
24 #include "JSString.h"
25
26 #include "JSGlobalObject.h"
27 #include "JSObject.h"
28 #include "Operations.h"
29 #include "StringObject.h"
30 #include "StringPrototype.h"
31
32 namespace JSC {
33
destructNonRecursive()34 void JSString::Rope::destructNonRecursive()
35 {
36 Vector<Rope*, 32> workQueue;
37 Rope* rope = this;
38
39 while (true) {
40 unsigned length = rope->ropeLength();
41 for (unsigned i = 0; i < length; ++i) {
42 Fiber& fiber = rope->fibers(i);
43 if (fiber.isString())
44 fiber.string()->deref();
45 else {
46 Rope* nextRope = fiber.rope();
47 if (nextRope->hasOneRef())
48 workQueue.append(nextRope);
49 else
50 nextRope->deref();
51 }
52 }
53 if (rope != this)
54 fastFree(rope);
55
56 if (workQueue.isEmpty())
57 return;
58
59 rope = workQueue.last();
60 workQueue.removeLast();
61 }
62 }
63
~Rope()64 JSString::Rope::~Rope()
65 {
66 destructNonRecursive();
67 }
68
69 // Overview: this methods converts a JSString from holding a string in rope form
70 // down to a simple UString representation. It does so by building up the string
71 // backwards, since we want to avoid recursion, we expect that the tree structure
72 // representing the rope is likely imbalanced with more nodes down the left side
73 // (since appending to the string is likely more common) - and as such resolving
74 // in this fashion should minimize work queue size. (If we built the queue forwards
75 // we would likely have to place all of the constituent UString::Reps into the
76 // Vector before performing any concatenation, but by working backwards we likely
77 // only fill the queue with the number of substrings at any given level in a
78 // rope-of-ropes.)
resolveRope(ExecState * exec) const79 void JSString::resolveRope(ExecState* exec) const
80 {
81 ASSERT(isRope());
82
83 // Allocate the buffer to hold the final string, position initially points to the end.
84 UChar* buffer;
85 if (PassRefPtr<UStringImpl> newImpl = UStringImpl::tryCreateUninitialized(m_stringLength, buffer))
86 m_value = newImpl;
87 else {
88 for (unsigned i = 0; i < m_ropeLength; ++i) {
89 m_fibers[i].deref();
90 m_fibers[i] = static_cast<void*>(0);
91 }
92 m_ropeLength = 0;
93 ASSERT(!isRope());
94 ASSERT(m_value == UString());
95 throwOutOfMemoryError(exec);
96 return;
97 }
98 UChar* position = buffer + m_stringLength;
99
100 // Start with the current Rope.
101 Vector<Rope::Fiber, 32> workQueue;
102 Rope::Fiber currentFiber;
103 for (unsigned i = 0; i < (m_ropeLength - 1); ++i)
104 workQueue.append(m_fibers[i]);
105 currentFiber = m_fibers[m_ropeLength - 1];
106 while (true) {
107 if (currentFiber.isRope()) {
108 Rope* rope = currentFiber.rope();
109 // Copy the contents of the current rope into the workQueue, with the last item in 'currentFiber'
110 // (we will be working backwards over the rope).
111 unsigned ropeLengthMinusOne = rope->ropeLength() - 1;
112 for (unsigned i = 0; i < ropeLengthMinusOne; ++i)
113 workQueue.append(rope->fibers(i));
114 currentFiber = rope->fibers(ropeLengthMinusOne);
115 } else {
116 UString::Rep* string = currentFiber.string();
117 unsigned length = string->size();
118 position -= length;
119 UStringImpl::copyChars(position, string->data(), length);
120
121 // Was this the last item in the work queue?
122 if (workQueue.isEmpty()) {
123 // Create a string from the UChar buffer, clear the rope RefPtr.
124 ASSERT(buffer == position);
125 for (unsigned i = 0; i < m_ropeLength; ++i) {
126 m_fibers[i].deref();
127 m_fibers[i] = static_cast<void*>(0);
128 }
129 m_ropeLength = 0;
130
131 ASSERT(!isRope());
132 return;
133 }
134
135 // No! - set the next item up to process.
136 currentFiber = workQueue.last();
137 workQueue.removeLast();
138 }
139 }
140 }
141
toPrimitive(ExecState *,PreferredPrimitiveType) const142 JSValue JSString::toPrimitive(ExecState*, PreferredPrimitiveType) const
143 {
144 return const_cast<JSString*>(this);
145 }
146
getPrimitiveNumber(ExecState * exec,double & number,JSValue & result)147 bool JSString::getPrimitiveNumber(ExecState* exec, double& number, JSValue& result)
148 {
149 result = this;
150 number = value(exec).toDouble();
151 return false;
152 }
153
toBoolean(ExecState *) const154 bool JSString::toBoolean(ExecState*) const
155 {
156 return m_stringLength;
157 }
158
toNumber(ExecState * exec) const159 double JSString::toNumber(ExecState* exec) const
160 {
161 return value(exec).toDouble();
162 }
163
toString(ExecState * exec) const164 UString JSString::toString(ExecState* exec) const
165 {
166 return value(exec);
167 }
168
toThisString(ExecState * exec) const169 UString JSString::toThisString(ExecState* exec) const
170 {
171 return value(exec);
172 }
173
toThisJSString(ExecState *)174 JSString* JSString::toThisJSString(ExecState*)
175 {
176 return this;
177 }
178
create(ExecState * exec,JSString * string)179 inline StringObject* StringObject::create(ExecState* exec, JSString* string)
180 {
181 return new (exec) StringObject(exec->lexicalGlobalObject()->stringObjectStructure(), string);
182 }
183
toObject(ExecState * exec) const184 JSObject* JSString::toObject(ExecState* exec) const
185 {
186 return StringObject::create(exec, const_cast<JSString*>(this));
187 }
188
toThisObject(ExecState * exec) const189 JSObject* JSString::toThisObject(ExecState* exec) const
190 {
191 return StringObject::create(exec, const_cast<JSString*>(this));
192 }
193
getOwnPropertySlot(ExecState * exec,const Identifier & propertyName,PropertySlot & slot)194 bool JSString::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
195 {
196 // The semantics here are really getPropertySlot, not getOwnPropertySlot.
197 // This function should only be called by JSValue::get.
198 if (getStringPropertySlot(exec, propertyName, slot))
199 return true;
200 if (propertyName == exec->propertyNames().underscoreProto) {
201 slot.setValue(exec->lexicalGlobalObject()->stringPrototype());
202 return true;
203 }
204 slot.setBase(this);
205 JSObject* object;
206 for (JSValue prototype = exec->lexicalGlobalObject()->stringPrototype(); !prototype.isNull(); prototype = object->prototype()) {
207 object = asObject(prototype);
208 if (object->getOwnPropertySlot(exec, propertyName, slot))
209 return true;
210 }
211 slot.setUndefined();
212 return true;
213 }
214
getStringPropertyDescriptor(ExecState * exec,const Identifier & propertyName,PropertyDescriptor & descriptor)215 bool JSString::getStringPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor)
216 {
217 if (propertyName == exec->propertyNames().length) {
218 descriptor.setDescriptor(jsNumber(exec, m_stringLength), DontEnum | DontDelete | ReadOnly);
219 return true;
220 }
221
222 bool isStrictUInt32;
223 unsigned i = propertyName.toStrictUInt32(&isStrictUInt32);
224 if (isStrictUInt32 && i < m_stringLength) {
225 descriptor.setDescriptor(jsSingleCharacterSubstring(exec, value(exec), i), DontDelete | ReadOnly);
226 return true;
227 }
228
229 return false;
230 }
231
getOwnPropertyDescriptor(ExecState * exec,const Identifier & propertyName,PropertyDescriptor & descriptor)232 bool JSString::getOwnPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor)
233 {
234 if (getStringPropertyDescriptor(exec, propertyName, descriptor))
235 return true;
236 if (propertyName != exec->propertyNames().underscoreProto)
237 return false;
238 descriptor.setDescriptor(exec->lexicalGlobalObject()->stringPrototype(), DontEnum);
239 return true;
240 }
241
getOwnPropertySlot(ExecState * exec,unsigned propertyName,PropertySlot & slot)242 bool JSString::getOwnPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
243 {
244 // The semantics here are really getPropertySlot, not getOwnPropertySlot.
245 // This function should only be called by JSValue::get.
246 if (getStringPropertySlot(exec, propertyName, slot))
247 return true;
248 return JSString::getOwnPropertySlot(exec, Identifier::from(exec, propertyName), slot);
249 }
250
251 } // namespace JSC
252