content/renderer/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 CONTENT_RENDERER_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_
   6 #define CONTENT_RENDERER_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/strings/nullable_string16.h"
  13 #include "content/common/content_export.h"
  14 #include "url/gurl.h"
  15
  16 namespace content {
  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 CONTENT_EXPORT DOMStorageCachedArea
  28     : public base::RefCounted<DOMStorageCachedArea> {
  29  public:
  30   DOMStorageCachedArea(int64 namespace_id,
  31                        const GURL& origin,
  32                        DOMStorageProxy* proxy);
  33
  34   int64 namespace_id() const { return namespace_id_; }
  35   const GURL& origin() const { return origin_; }
  36
  37   unsigned GetLength(int connection_id);
  38   base::NullableString16 GetKey(int connection_id, unsigned index);
  39   base::NullableString16 GetItem(int connection_id, const base::string16& key);
  40   bool SetItem(int connection_id,
  41                const base::string16& key,
  42                const base::string16& value,
  43                const GURL& page_url);
  44   void RemoveItem(int connection_id,
  45                   const base::string16& key,
  46                   const GURL& page_url);
  47   void Clear(int connection_id, const GURL& page_url);
  48
  49   void ApplyMutation(const base::NullableString16& key,
  50                      const base::NullableString16& new_value);
  51
  52   size_t MemoryBytesUsedByCache() const;
  53
  54   // Resets the object back to its newly constructed state.
  55   void Reset();
  56
  57  private:
  58   friend class DOMStorageCachedAreaTest;
  59   friend class base::RefCounted<DOMStorageCachedArea>;
  60   ~DOMStorageCachedArea();
  61
  62   // Primes the cache, loading all values for the area.
  63   void Prime(int connection_id);
  64   void PrimeIfNeeded(int connection_id) {
  65     if (!map_.get())
  66       Prime(connection_id);
  67   }
  68
  69   // Async completion callbacks for proxied operations.
  70   // These are used to maintain cache consistency by preventing
  71   // mutation events from other processes from overwriting local
  72   // changes made after the mutation.
  73   void OnLoadComplete(bool success);
  74   void OnSetItemComplete(const base::string16& key, bool success);
  75   void OnClearComplete(bool success);
  76   void OnRemoveItemComplete(const base::string16& key, bool success);
  77
  78   bool should_ignore_key_mutation(const base::string16& key) const {
  79     return ignore_key_mutations_.find(key) != ignore_key_mutations_.end();
  80   }
  81
  82   bool ignore_all_mutations_;
  83   std::map<base::string16, int> ignore_key_mutations_;
  84
  85   int64 namespace_id_;
  86   GURL origin_;
  87   scoped_refptr<DOMStorageMap> map_;
  88   scoped_refptr<DOMStorageProxy> proxy_;
  89   // Sometimes, we need to send  messages to the browser for each get access,
  90   // for logging purposes. However, we only do this for a fixed maximum number
  91   // of gets. Here, we keep track of how many remaining get log messages we
  92   // need to send.
  93   int remaining_log_get_messages_;
  94   base::WeakPtrFactory<DOMStorageCachedArea> weak_factory_;
  95 };
  96
  97 }  // namespace content
  98
  99 #endif  // CONTENT_RENDERER_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_