Refactor common invalidation framework types

sync/notifier/ordered_invalidation_list.h

+// Copyright 2013 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 SYNC_INTERNAL_API_PUBLIC_BASE_INVALIDATION_LIST_H_
+#define SYNC_INTERNAL_API_PUBLIC_BASE_INVALIDATION_LIST_H_
+
+#include <set>
+
+#include "base/memory/scoped_ptr.h"
+#include "sync/base/sync_export.h"
+#include "sync/internal_api/public/base/invalidation.h"
+
+namespace base {
+class ListValue;
+}  // namespace base
+
+namespace syncer {
+
+struct InvalidationVersionLessThan {
+  bool operator()(const Invalidation& a, const Invalidation& b);
+};
+
+// Holds a list of invalidations that all share the same Object ID.
+//
+// The list is kept sorted by version to make it easier to perform common
+// operations, like checking for an unknown version invalidation or fetching the
+// highest invalidation with the highest version number.
+class SYNC_EXPORT OrderedInvalidationList {
+ public:
+  typedef std::set<Invalidation, InvalidationVersionLessThan> InvalidationsSet;
+  typedef InvalidationsSet::const_iterator const_iterator;
+  typedef InvalidationsSet::const_reverse_iterator const_reverse_iterator;
+
+  OrderedInvalidationList();
+  ~OrderedInvalidationList();
+
+  void Insert(const Invalidation& invalidation);
+  void InsertAll(const OrderedInvalidationList& other);
+  void Clear();
+
+  // Returns true if this list contains an unknown version.
+  //
+  // Unknown version invalidations always end up at the start of the list,
+  // because they have the lowest possible value in the sort ordering.
+  bool StartsWithUnknownVersion() const;
+  size_t GetSize() const;
+  bool IsEmpty() const;
+  bool operator==(const OrderedInvalidationList& other) const;
+
+  const_iterator begin() const;
+  const_iterator end() const;
+  const_reverse_iterator rbegin() const;
+  const_reverse_iterator rend() const;
+  const Invalidation& back() const;
+
+  scoped_ptr<base::ListValue> ToValue() const;
+  bool ResetFromValue(const base::ListValue& list);
+
+ private:
+  InvalidationsSet invalidations_;
+};
+
+}  // syncer
+
+#endif  // SYNC_INTERNAL_API_PUBLIC_BASE_INVALIDATION_LIST_H_