content/common/dom_storage/dom_storage_map.h

   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
  16 namespace 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.
  21 class 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   static size_t CountBytes(const DOMStorageValuesMap& values);
  50
  51  private:
  52   friend class base::RefCountedThreadSafe<DOMStorageMap>;
  53   ~DOMStorageMap();
  54
  55   void ResetKeyIterator();
  56
  57   DOMStorageValuesMap values_;
  58   DOMStorageValuesMap::const_iterator key_iterator_;
  59   unsigned last_key_index_;
  60   size_t bytes_used_;
  61   size_t quota_;
  62 };
  63
  64 }  // namespace content
  65
  66 #endif  // CONTENT_COMMON_DOM_STORAGE_DOM_STORAGE_MAP_H_