1 // Copyright 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "content/common/dom_storage/dom_storage_map.h"
6
7 #include "base/logging.h"
8
9 namespace content {
10
11 namespace {
12
size_of_item(const base::string16 & key,const base::string16 & value)13 size_t size_of_item(const base::string16& key, const base::string16& value) {
14 return (key.length() + value.length()) * sizeof(base::char16);
15 }
16
CountBytes(const DOMStorageValuesMap & values)17 size_t CountBytes(const DOMStorageValuesMap& values) {
18 if (values.size() == 0)
19 return 0;
20
21 size_t count = 0;
22 DOMStorageValuesMap::const_iterator it = values.begin();
23 for (; it != values.end(); ++it)
24 count += size_of_item(it->first, it->second.string());
25 return count;
26 }
27
28 } // namespace
29
DOMStorageMap(size_t quota)30 DOMStorageMap::DOMStorageMap(size_t quota)
31 : bytes_used_(0),
32 quota_(quota) {
33 ResetKeyIterator();
34 }
35
~DOMStorageMap()36 DOMStorageMap::~DOMStorageMap() {}
37
Length() const38 unsigned DOMStorageMap::Length() const {
39 return values_.size();
40 }
41
Key(unsigned index)42 base::NullableString16 DOMStorageMap::Key(unsigned index) {
43 if (index >= values_.size())
44 return base::NullableString16();
45 while (last_key_index_ != index) {
46 if (last_key_index_ > index) {
47 --key_iterator_;
48 --last_key_index_;
49 } else {
50 ++key_iterator_;
51 ++last_key_index_;
52 }
53 }
54 return base::NullableString16(key_iterator_->first, false);
55 }
56
GetItem(const base::string16 & key) const57 base::NullableString16 DOMStorageMap::GetItem(const base::string16& key) const {
58 DOMStorageValuesMap::const_iterator found = values_.find(key);
59 if (found == values_.end())
60 return base::NullableString16();
61 return found->second;
62 }
63
SetItem(const base::string16 & key,const base::string16 & value,base::NullableString16 * old_value)64 bool DOMStorageMap::SetItem(
65 const base::string16& key, const base::string16& value,
66 base::NullableString16* old_value) {
67 DOMStorageValuesMap::const_iterator found = values_.find(key);
68 if (found == values_.end())
69 *old_value = base::NullableString16();
70 else
71 *old_value = found->second;
72
73 size_t old_item_size = old_value->is_null() ?
74 0 : size_of_item(key, old_value->string());
75 size_t new_item_size = size_of_item(key, value);
76 size_t new_bytes_used = bytes_used_ - old_item_size + new_item_size;
77
78 // Only check quota if the size is increasing, this allows
79 // shrinking changes to pre-existing files that are over budget.
80 if (new_item_size > old_item_size && new_bytes_used > quota_)
81 return false;
82
83 values_[key] = base::NullableString16(value, false);
84 ResetKeyIterator();
85 bytes_used_ = new_bytes_used;
86 return true;
87 }
88
RemoveItem(const base::string16 & key,base::string16 * old_value)89 bool DOMStorageMap::RemoveItem(
90 const base::string16& key,
91 base::string16* old_value) {
92 DOMStorageValuesMap::iterator found = values_.find(key);
93 if (found == values_.end())
94 return false;
95 *old_value = found->second.string();
96 values_.erase(found);
97 ResetKeyIterator();
98 bytes_used_ -= size_of_item(key, *old_value);
99 return true;
100 }
101
SwapValues(DOMStorageValuesMap * values)102 void DOMStorageMap::SwapValues(DOMStorageValuesMap* values) {
103 // Note: A pre-existing file may be over the quota budget.
104 values_.swap(*values);
105 bytes_used_ = CountBytes(values_);
106 ResetKeyIterator();
107 }
108
DeepCopy() const109 DOMStorageMap* DOMStorageMap::DeepCopy() const {
110 DOMStorageMap* copy = new DOMStorageMap(quota_);
111 copy->values_ = values_;
112 copy->bytes_used_ = bytes_used_;
113 copy->ResetKeyIterator();
114 return copy;
115 }
116
ResetKeyIterator()117 void DOMStorageMap::ResetKeyIterator() {
118 key_iterator_ = values_.begin();
119 last_key_index_ = 0;
120 }
121
122 } // namespace content
123