components/enhanced_bookmarks/item_position.h

   1 // Copyright 2014 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 COMPONENTS_ENHANCED_BOOKMARKS_ITEM_POSITION_H_
   6 #define COMPONENTS_ENHANCED_BOOKMARKS_ITEM_POSITION_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 namespace enhanced_bookmarks {
  12
  13 // Convenience class for generating string based relative ordering between
  14 // bookmark nodes.
  15 class ItemPosition {
  16  public:
  17   ~ItemPosition();
  18
  19   // Creates a position suitable to use as a starting point.
  20   static ItemPosition CreateInitialPosition();
  21
  22   // Creates positions relative to other positions.
  23   static ItemPosition CreateBefore(const ItemPosition& other);
  24   static ItemPosition CreateBetween(const ItemPosition& before,
  25                                     const ItemPosition& after);
  26   static ItemPosition CreateAfter(const ItemPosition& other);
  27
  28   bool IsValid() const;
  29
  30   // Returns a string representation of the position. The string representations
  31   // of two position have the same ordering as the positions themselves when
  32   // compared using ASCII order.
  33   std::string ToString() const;
  34
  35   // Comparison functions.
  36   bool Equals(const ItemPosition& other) const;
  37   bool LessThan(const ItemPosition& other) const;
  38
  39  private:
  40   typedef std::vector<unsigned char> PositionVector;
  41
  42   ItemPosition();
  43   explicit ItemPosition(const PositionVector& position);
  44
  45   static PositionVector CreateBeforeImpl(const PositionVector& before,
  46                                          size_t from_index);
  47   static PositionVector CreateBetweenImpl(const PositionVector& before,
  48                                           const PositionVector& after);
  49   static PositionVector CreateAfterImpl(const PositionVector& after,
  50                                         size_t from_index);
  51
  52   PositionVector position_;
  53 };
  54
  55 }  // namespace enhanced_bookmarks
  56
  57 #endif  // COMPONENTS_ENHANCED_BOOKMARKS_ITEM_POSITION_H_