DomStorageCachedArea + DomStorageProxy interface and unittests. These classes aren't used yet.

webkit/dom_storage/dom_storage_cached_area.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WEBKIT_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_
+#define WEBKIT_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_
+#pragma once
+
+#include <map>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/nullable_string16.h"
+#include "googleurl/src/gurl.h"
+
+namespace dom_storage {
+
+class DomStorageMap;
+class DomStorageProxy;
+
+class DomStorageCachedArea : public base::RefCounted<DomStorageCachedArea> {
+ public:
+  DomStorageCachedArea(int64 namespace_id, const GURL& origin,
+                       DomStorageProxy* proxy);
+
+  int64 namespace_id() const { return namespace_id_; }
+  const GURL& origin() const { return origin_; }
+
+  unsigned GetLength(int connection_id);
+  NullableString16 GetKey(int connection_id, unsigned index);
+  NullableString16 GetItem(int connection_id, const string16& key);
+  bool SetItem(int connection_id, const string16& key, const string16& value,
+               const GURL& page_url);
+  void RemoveItem(int connection_id, const string16& key,
+                  const GURL& page_url);
+  void Clear(int connection_id, const GURL& page_url);
+
+  void ApplyMutation(const NullableString16& key,
+                     const NullableString16& new_value);
+
+ private:
+  friend class DomStorageCachedAreaTest;
+  friend class base::RefCounted<DomStorageCachedArea>;
+  ~DomStorageCachedArea();
+
+  // Primes the cache, loading all values for the area.

[jsbell, 2012/05/24 20:20:22]

Can you add a comment near the top of the class indicating that this is a
complete cache, not a sparse cache?

[michaeln, 2012/05/24 20:43:11]

Done.

// Unlike the other classes in the dom_storage library, this one is intended
// for use in renderer processes. It maintains a complete cach of the an
// origin's Map of key/value pairs for fast access. The cache is primed on
// first access and changes are written to the backend thru the |proxy|.
// Mutations originating in other processes are applied to the cache via
// the ApplyMutation method.

+  void Prime(int connection_id);
+  void PrimeIfNeeded(int connection_id) {
+    if (!map_)
+      Prime(connection_id);
+  }
+
+  // Resets the class back to its newly constructed state.

[jsbell, 2012/05/24 20:20:22]

Nit: s/class/object/

[michaeln, 2012/05/24 20:43:11]

Done.

+  void Reset();
+
+  // Async completion callbacks for proxied operations.
+  // These are used to maintain cache consistency by preventing
+  // mutation events from other processes from overwriting local
+  // changes made after the mutation.
+  void OnLoadComplete(bool success);
+  void OnSetItemComplete(const string16& key, bool success);
+  void OnClearComplete(bool success);
+  void OnRemoveItemComplete(const string16& key, bool success);
+
+  bool should_ignore_key_mutation(const string16& key) const {
+    return ignore_key_mutations_.find(key) != ignore_key_mutations_.end();
+  }
+
+  bool ignore_all_mutations_;
+  std::map<string16, int> ignore_key_mutations_;
+
+  int64 namespace_id_;
+  GURL origin_;
+  scoped_refptr<DomStorageMap> map_;
+  scoped_refptr<DomStorageProxy> proxy_;
+  base::WeakPtrFactory<DomStorageCachedArea> weak_factory_;
+};
+
+}  // namespace dom_storage
+
+#endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_CACHED_AREA_H_