TableView: 3-phase ToggleSortOrder (sorted/reversed/unsorted)

ui/views/controls/table/table_view.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 UI_VIEWS_CONTROLS_TABLE_TABLE_VIEW_VIEWS_H_
 #define UI_VIEWS_CONTROLS_TABLE_TABLE_VIEW_VIEWS_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 136 matching lines @@
   }
   TableViewObserver* observer() const { return table_view_observer_; }
 
   const std::vector<VisibleColumn>& visible_columns() const {
     return visible_columns_;
   }
 
   // Sets the width of the column. |index| is in terms of |visible_columns_|.
   void SetVisibleColumnWidth(int index, int width);
 
-  // Toggles the sort order of the specified visible column index.
+  // Modify the table sort order, depending on a clicked column and the previous
+  // table sort order. Does nothing if this column is not sortable.
+  //
+  // When called repeatedly on the same sortable column, the sort order will
+  // cycle through three states in order: sorted -> reverse-sorted -> unsorted.
+  // When switching from one sort column to another, the previous sort column
+  // will be remembered and used as a secondary sort key.
   void ToggleSortOrder(int visible_column_index);
 
   const SortDescriptors& sort_descriptors() const { return sort_descriptors_; }
+  void SetSortDescriptors(SortDescriptors descriptors);

[sky, 2016/07/18 16:18:58]

nit: const SortDescriptors& . I realize what you have is likely just as
efficient, but seeing the value type requires more thought than had you just
used a const&.

[ncarter (slow), 2016/07/25 20:04:01]

Done.

   bool is_sorted() const { return !sort_descriptors_.empty(); }
 
   // Maps from the index in terms of the model to that of the view.
   int ModelToView(int model_index) const;
 
   // Maps from the index in terms of the view to that of the model.
   int ViewToModel(int view_index) const;
 
   int row_height() const { return row_height_; }
 
@@ skipping 49 matching lines @@
   // Used by AdvanceSelection() to determine the direction to change the
   // selection.
   enum AdvanceDirection {
     ADVANCE_DECREMENT,
     ADVANCE_INCREMENT,
   };
 
   // Invoked when the number of rows changes in some way.
   void NumRowsChanged();
 
-  // Resets the sort descriptions.
-  void SetSortDescriptors(const SortDescriptors& sort_descriptors);

[sky, 2016/07/18 16:18:58]

Move implementation to match new location.

[ncarter (slow), 2016/07/25 20:04:01]

Done.

-
   // Does the actual sort and updates the mappings (|view_to_model_| and
   // |model_to_view_|) appropriately.
   void SortItemsAndUpdateMapping();
 
   // Used to sort the two rows. Returns a value < 0, == 0 or > 0 indicating
   // whether the row2 comes before row1, row2 is the same as row1 or row1 comes
   // after row2. This invokes CompareValues on the model with the sorted column.
   int CompareRows(int model_row1, int model_row2);
 
   // Returns the bounds of the specified row.
@@ skipping 114 matching lines @@
 
   // True if in SetVisibleColumnWidth().
   bool in_set_visible_column_width_;
 
   DISALLOW_COPY_AND_ASSIGN(TableView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_TABLE_TABLE_VIEW_VIEWS_H_