1 /*
2 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #include "config.h"
27 #include "StorageMap.h"
28
29 #if ENABLE(DOM_STORAGE)
30
31 namespace WebCore {
32
create(unsigned quota)33 PassRefPtr<StorageMap> StorageMap::create(unsigned quota)
34 {
35 return adoptRef(new StorageMap(quota));
36 }
37
StorageMap(unsigned quota)38 StorageMap::StorageMap(unsigned quota)
39 : m_iterator(m_map.end())
40 , m_iteratorIndex(UINT_MAX)
41 , m_quotaSize(quota) // quota measured in bytes
42 , m_currentLength(0)
43 {
44 }
45
copy()46 PassRefPtr<StorageMap> StorageMap::copy()
47 {
48 RefPtr<StorageMap> newMap = create(m_quotaSize);
49 newMap->m_map = m_map;
50 newMap->m_currentLength = m_currentLength;
51 return newMap.release();
52 }
53
invalidateIterator()54 void StorageMap::invalidateIterator()
55 {
56 m_iterator = m_map.end();
57 m_iteratorIndex = UINT_MAX;
58 }
59
setIteratorToIndex(unsigned index)60 void StorageMap::setIteratorToIndex(unsigned index)
61 {
62 // FIXME: Once we have bidirectional iterators for HashMap we can be more intelligent about this.
63 // The requested index will be closest to begin(), our current iterator, or end(), and we
64 // can take the shortest route.
65 // Until that mechanism is available, we'll always increment our iterator from begin() or current.
66
67 if (m_iteratorIndex == index)
68 return;
69
70 if (index < m_iteratorIndex) {
71 m_iteratorIndex = 0;
72 m_iterator = m_map.begin();
73 ASSERT(m_iterator != m_map.end());
74 }
75
76 while (m_iteratorIndex < index) {
77 ++m_iteratorIndex;
78 ++m_iterator;
79 ASSERT(m_iterator != m_map.end());
80 }
81 }
82
length() const83 unsigned StorageMap::length() const
84 {
85 return m_map.size();
86 }
87
key(unsigned index)88 String StorageMap::key(unsigned index)
89 {
90 if (index >= length())
91 return String();
92
93 setIteratorToIndex(index);
94 return m_iterator->first;
95 }
96
getItem(const String & key) const97 String StorageMap::getItem(const String& key) const
98 {
99 return m_map.get(key);
100 }
101
setItem(const String & key,const String & value,String & oldValue,bool & quotaException)102 PassRefPtr<StorageMap> StorageMap::setItem(const String& key, const String& value, String& oldValue, bool& quotaException)
103 {
104 ASSERT(!value.isNull());
105 quotaException = false;
106
107 // Implement copy-on-write semantics here. We're guaranteed that the only refs of StorageMaps belong to Storage objects
108 // so if more than one Storage object refs this map, copy it before mutating it.
109 if (refCount() > 1) {
110 RefPtr<StorageMap> newStorageMap = copy();
111 newStorageMap->setItem(key, value, oldValue, quotaException);
112 return newStorageMap.release();
113 }
114
115 // Quota tracking. This is done in a couple of steps to keep the overflow tracking simple.
116 unsigned newLength = m_currentLength;
117 bool overflow = newLength + value.length() < newLength;
118 newLength += value.length();
119
120 oldValue = m_map.get(key);
121 overflow |= newLength - oldValue.length() > newLength;
122 newLength -= oldValue.length();
123
124 unsigned adjustedKeyLength = oldValue.isNull() ? key.length() : 0;
125 overflow |= newLength + adjustedKeyLength < newLength;
126 newLength += adjustedKeyLength;
127
128 ASSERT(!overflow); // Overflow is bad...even if quotas are off.
129 bool overQuota = newLength > m_quotaSize / sizeof(UChar);
130 if (m_quotaSize != noQuota && (overflow || overQuota)) {
131 quotaException = true;
132 return 0;
133 }
134 m_currentLength = newLength;
135
136 pair<HashMap<String, String>::iterator, bool> addResult = m_map.add(key, value);
137 if (!addResult.second)
138 addResult.first->second = value;
139
140 invalidateIterator();
141
142 return 0;
143 }
144
removeItem(const String & key,String & oldValue)145 PassRefPtr<StorageMap> StorageMap::removeItem(const String& key, String& oldValue)
146 {
147 // Implement copy-on-write semantics here. We're guaranteed that the only refs of StorageMaps belong to Storage objects
148 // so if more than one Storage object refs this map, copy it before mutating it.
149 if (refCount() > 1) {
150 RefPtr<StorageMap> newStorage = copy();
151 newStorage->removeItem(key, oldValue);
152 return newStorage.release();
153 }
154
155 oldValue = m_map.take(key);
156 if (!oldValue.isNull()) {
157 invalidateIterator();
158 ASSERT(m_currentLength - key.length() <= m_currentLength);
159 m_currentLength -= key.length();
160 }
161 ASSERT(m_currentLength - oldValue.length() <= m_currentLength);
162 m_currentLength -= oldValue.length();
163
164 return 0;
165 }
166
contains(const String & key) const167 bool StorageMap::contains(const String& key) const
168 {
169 return m_map.contains(key);
170 }
171
importItem(const String & key,const String & value)172 void StorageMap::importItem(const String& key, const String& value)
173 {
174 // Be sure to copy the keys/values as items imported on a background thread are destined
175 // to cross a thread boundary
176 pair<HashMap<String, String>::iterator, bool> result = m_map.add(key.threadsafeCopy(), value.threadsafeCopy());
177 ASSERT(result.second); // True if the key didn't exist previously.
178
179 ASSERT(m_currentLength + key.length() >= m_currentLength);
180 m_currentLength += key.length();
181 ASSERT(m_currentLength + value.length() >= m_currentLength);
182 m_currentLength += value.length();
183 }
184
185 }
186
187 #endif // ENABLE(DOM_STORAGE)
188