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#ifndef CONTENT_COMMON_DOM_STORAGE_DOM_STORAGE_MAP_H_
6#define CONTENT_COMMON_DOM_STORAGE_DOM_STORAGE_MAP_H_
7
8#include <map>
9
10#include "base/memory/ref_counted.h"
11#include "base/strings/nullable_string16.h"
12#include "base/strings/string16.h"
13#include "content/common/content_export.h"
14#include "content/common/dom_storage/dom_storage_types.h"
15
16namespace content {
17
18// A wrapper around a std::map that adds refcounting and
19// tracks the size in bytes of the keys/values, enforcing a quota.
20// See class comments for DOMStorageContextImpl for a larger overview.
21class CONTENT_EXPORT DOMStorageMap
22    : public base::RefCountedThreadSafe<DOMStorageMap> {
23 public:
24  explicit DOMStorageMap(size_t quota);
25
26  unsigned Length() const;
27  base::NullableString16 Key(unsigned index);
28  base::NullableString16 GetItem(const base::string16& key) const;
29  bool SetItem(const base::string16& key, const base::string16& value,
30               base::NullableString16* old_value);
31  bool RemoveItem(const base::string16& key, base::string16* old_value);
32
33  // Swaps this instances values_ with |map|.
34  // Note: to grandfather in pre-existing files that are overbudget,
35  // this method does not do quota checking.
36  void SwapValues(DOMStorageValuesMap* map);
37
38  // Writes a copy of the current set of values_ to the |map|.
39  void ExtractValues(DOMStorageValuesMap* map) const { *map = values_; }
40
41  // Creates a new instance of DOMStorageMap containing
42  // a deep copy of values_.
43  DOMStorageMap* DeepCopy() const;
44
45  size_t bytes_used() const { return bytes_used_; }
46  size_t quota() const { return quota_; }
47  void set_quota(size_t quota) { quota_ = quota; }
48
49 private:
50  friend class base::RefCountedThreadSafe<DOMStorageMap>;
51  ~DOMStorageMap();
52
53  void ResetKeyIterator();
54
55  DOMStorageValuesMap values_;
56  DOMStorageValuesMap::const_iterator key_iterator_;
57  unsigned last_key_index_;
58  size_t bytes_used_;
59  size_t quota_;
60};
61
62}  // namespace content
63
64#endif  // CONTENT_COMMON_DOM_STORAGE_DOM_STORAGE_MAP_H_
65