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#include <wtf/SetForScope.h>
30
31namespace WebCore {
32
33Ref<StorageMap> StorageMap::create(unsigned quota)
34{
35 return adoptRef(*new StorageMap(quota));
36}
37
38StorageMap::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
46Ref<StorageMap> StorageMap::copy()
47{
48 Ref<StorageMap> newMap = create(m_quotaSize);
49 newMap->m_map = m_map;
50 newMap->m_currentLength = m_currentLength;
51 return newMap;
52}
53
54void StorageMap::invalidateIterator()
55{
56 m_iterator = m_map.end();
57 m_iteratorIndex = UINT_MAX;
58}
59
60void 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
83unsigned StorageMap::length() const
84{
85 return m_map.size();
86}
87
88String StorageMap::key(unsigned index)
89{
90 if (index >= length())
91 return String();
92
93 setIteratorToIndex(index);
94 return m_iterator->key;
95}
96
97String StorageMap::getItem(const String& key) const
98{
99 return m_map.get(key);
100}
101
102RefPtr<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;
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 nullptr;
133 }
134 m_currentLength = newLength;
135
136 HashMap<String, String>::AddResult addResult = m_map.add(key, value);
137 if (!addResult.isNewEntry)
138 addResult.iterator->value = value;
139
140 invalidateIterator();
141
142 return nullptr;
143}
144
145RefPtr<StorageMap> StorageMap::setItemIgnoringQuota(const String& key, const String& value)
146{
147 SetForScope<unsigned> quotaSizeChange(m_quotaSize, static_cast<unsigned>(noQuota));
148
149 String oldValue;
150 bool quotaException;
151
152 RefPtr<StorageMap> map = setItem(key, value, oldValue, quotaException);
153 ASSERT(!quotaException);
154
155 return map;
156}
157
158RefPtr<StorageMap> StorageMap::removeItem(const String& key, String& oldValue)
159{
160 // Implement copy-on-write semantics here. We're guaranteed that the only refs of StorageMaps belong to Storage objects
161 // so if more than one Storage object refs this map, copy it before mutating it.
162 if (refCount() > 1) {
163 RefPtr<StorageMap> newStorage = copy();
164 newStorage->removeItem(key, oldValue);
165 return newStorage;
166 }
167
168 oldValue = m_map.take(key);
169 if (!oldValue.isNull()) {
170 invalidateIterator();
171 ASSERT(m_currentLength - key.length() <= m_currentLength);
172 m_currentLength -= key.length();
173 }
174 ASSERT(m_currentLength - oldValue.length() <= m_currentLength);
175 m_currentLength -= oldValue.length();
176
177 return nullptr;
178}
179
180bool StorageMap::contains(const String& key) const
181{
182 return m_map.contains(key);
183}
184
185void StorageMap::importItems(const HashMap<String, String>& items)
186{
187 for (auto& item : items) {
188 const String& key = item.key;
189 const String& value = item.value;
190
191 HashMap<String, String>::AddResult result = m_map.add(key, value);
192 ASSERT_UNUSED(result, result.isNewEntry); // True if the key didn't exist previously.
193
194 ASSERT(m_currentLength + key.length() >= m_currentLength);
195 m_currentLength += key.length();
196 ASSERT(m_currentLength + value.length() >= m_currentLength);
197 m_currentLength += value.length();
198 }
199}
200
201}
202