webkit/dom_storage/dom_storage_cached_area.h

   1 // Copyright (c) 2012 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 WEBKIT_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_
   6 #define WEBKIT_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_
   7
   8 #include <map>
   9
  10 #include "base/memory/ref_counted.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/nullable_string16.h"
  13 #include "googleurl/src/gurl.h"
  14 #include "webkit/storage/webkit_storage_export.h"
  15
  16 namespace dom_storage {
  17
  18 class DomStorageMap;
  19 class DomStorageProxy;
  20
  21 // Unlike the other classes in the dom_storage library, this one is intended
  22 // for use in renderer processes. It maintains a complete cache of the
  23 // origin's Map of key/value pairs for fast access. The cache is primed on
  24 // first access and changes are written to the backend thru the |proxy|.
  25 // Mutations originating in other processes are applied to the cache via
  26 // the ApplyMutation method.
  27 class WEBKIT_STORAGE_EXPORT DomStorageCachedArea :
  28       public base::RefCounted<DomStorageCachedArea> {
  29  public:
  30   DomStorageCachedArea(int64 namespace_id, const GURL& origin,
  31                        DomStorageProxy* proxy);
  32
  33   int64 namespace_id() const { return namespace_id_; }
  34   const GURL& origin() const { return origin_; }
  35
  36   unsigned GetLength(int connection_id);
  37   NullableString16 GetKey(int connection_id, unsigned index);
  38   NullableString16 GetItem(int connection_id, const base::string16& key);
  39   bool SetItem(int connection_id,
  40                const base::string16& key,
  41                const base::string16& value,
  42                const GURL& page_url);
  43   void RemoveItem(int connection_id, const base::string16& key,
  44                   const GURL& page_url);
  45   void Clear(int connection_id, const GURL& page_url);
  46
  47   void ApplyMutation(const NullableString16& key,
  48                      const NullableString16& new_value);
  49
  50   size_t MemoryBytesUsedByCache() const;
  51
  52  private:
  53   friend class DomStorageCachedAreaTest;
  54   friend class base::RefCounted<DomStorageCachedArea>;
  55   ~DomStorageCachedArea();
  56
  57   // Primes the cache, loading all values for the area.
  58   void Prime(int connection_id);
  59   void PrimeIfNeeded(int connection_id) {
  60     if (!map_)
  61       Prime(connection_id);
  62   }
  63
  64   // Resets the object back to its newly constructed state.
  65   void Reset();
  66
  67   // Async completion callbacks for proxied operations.
  68   // These are used to maintain cache consistency by preventing
  69   // mutation events from other processes from overwriting local
  70   // changes made after the mutation.
  71   void OnLoadComplete(bool success);
  72   void OnSetItemComplete(const base::string16& key, bool success);
  73   void OnClearComplete(bool success);
  74   void OnRemoveItemComplete(const base::string16& key, bool success);
  75
  76   bool should_ignore_key_mutation(const base::string16& key) const {
  77     return ignore_key_mutations_.find(key) != ignore_key_mutations_.end();
  78   }
  79
  80   bool ignore_all_mutations_;
  81   std::map<base::string16, int> ignore_key_mutations_;
  82
  83   int64 namespace_id_;
  84   GURL origin_;
  85   scoped_refptr<DomStorageMap> map_;
  86   scoped_refptr<DomStorageProxy> proxy_;
  87   base::WeakPtrFactory<DomStorageCachedArea> weak_factory_;
  88 };
  89
  90 }  // namespace dom_storage
  91
  92 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_