[gtk/wip/otte/listview: 2165/2170] columnview: Add sorting

[Benjamin Otte <otte src gnome org>]

commit 2bed61a2d8ea6f935c0093b7baac294a514b7bc6
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Dec 4 08:13:13 2019 -0500

    columnview: Add sorting
    
    This is a somewhat large commit that:
    
    - Adds GtkColumnViewSorter
    This is a special-purpose, private sorter implementation which sorts
    according to multiple sorters, allowing each individual sorter to be
    inverted. This will be used with clickable column view headers.
    
    - Adds a read-only GtkColumnView::sorter property
    The GtkColumnView creates a GtkColumnViewSorter at startup that it uses
    for this property.
    
    - Adds a writable GtkColumnViewColumn::sorter property
    This allows defining per-column sorters. Whenever an application sets a
    sorter for a column, the header becomes clickable and whenever
    a header is clicked, that column's sorter is prepended to the list of
    sorters, unless it is already the first sorter, in which case we invert
    its order. No column can be in the list more than once.

 docs/reference/gtk/gtk4-sections.txt |   3 +
 docs/reference/gtk/meson.build       |   1 +
 gtk/gtkcolumnview.c                  |  55 +++++++
 gtk/gtkcolumnview.h                  |   6 +
 gtk/gtkcolumnviewcolumn.c            |  95 ++++++++++++
 gtk/gtkcolumnviewcolumn.h            |   7 +
 gtk/gtkcolumnviewcolumnprivate.h     |   3 +
 gtk/gtkcolumnviewprivate.h           |   1 +
 gtk/gtkcolumnviewsorter.c            | 282 +++++++++++++++++++++++++++++++++++
 gtk/gtkcolumnviewsorterprivate.h     |  53 +++++++
 gtk/meson.build                      |   1 +
 testsuite/gtk/defaultvalue.c         |   3 +-
 12 files changed, 509 insertions(+), 1 deletion(-)
---
diff --git a/docs/reference/gtk/gtk4-sections.txt b/docs/reference/gtk/gtk4-sections.txt
index a097eb62ed..e02b6aadcc 100644
--- a/docs/reference/gtk/gtk4-sections.txt
+++ b/docs/reference/gtk/gtk4-sections.txt
@@ -500,6 +500,7 @@ gtk_column_view_remove_column
 gtk_column_view_get_columns
 gtk_column_view_get_model
 gtk_column_view_set_model
+gtk_column_view_get_sorter
 gtk_column_view_get_show_separators
 gtk_column_view_set_show_separators
 <SUBSECTION Standard>
@@ -524,6 +525,8 @@ gtk_column_view_column_set_factory
 gtk_column_view_column_get_factory
 gtk_column_view_column_set_title
 gtk_column_view_column_get_title
+gtk_column_view_column_set_sorter
+gtk_column_view_column_get_sorter
 <SUBSECTION Standard>
 GTK_COLUMN_VIEW_COLUMN
 GTK_COLUMN_VIEW_COLUMN_CLASS
diff --git a/docs/reference/gtk/meson.build b/docs/reference/gtk/meson.build
index 781be3c52f..24d194d3bc 100644
--- a/docs/reference/gtk/meson.build
+++ b/docs/reference/gtk/meson.build
@@ -27,6 +27,7 @@ private_headers = [
   'gtkcolumnviewcolumnprivate.h',
   'gtkcolumnviewlayoutprivate.h',
   'gtkcolumnviewprivate.h',
+  'gtkcolumnviewsorterprivate.h',
   'gtkcolumnviewtitleprivate.h',
   'gtkcomboboxprivate.h',
   'gtkconstraintexpressionprivate.h',
diff --git a/gtk/gtkcolumnview.c b/gtk/gtkcolumnview.c
index d6170dfc46..9d3bf91299 100644
--- a/gtk/gtkcolumnview.c
+++ b/gtk/gtkcolumnview.c
@@ -26,6 +26,7 @@
 #include "gtkcolumnlistitemfactoryprivate.h"
 #include "gtkcolumnviewcolumnprivate.h"
 #include "gtkcolumnviewlayoutprivate.h"
+#include "gtkcolumnviewsorterprivate.h"
 #include "gtkcssnodeprivate.h"
 #include "gtkintl.h"
 #include "gtklistview.h"
@@ -42,6 +43,12 @@
  *
  * GtkColumnView is a widget to present a view into a large dynamic list of items
  * using multiple columns.
+ *
+ * It supports sorting that can be customized by the user by clicking on column
+ * view headers. To set this up, the #GtkSorter returned by gtk_column_view_get_sorter()
+ * must be attached to a sort model for the data that the view is showing, and the
+ * columns must have sorters attached to them by calling gtk_column_view_column_set_sorter().
+ * The initial sort order can be set with gtk_column_view_sort_by_column().
  */
 
 struct _GtkColumnView
@@ -54,6 +61,8 @@ struct _GtkColumnView
 
   GtkListView *listview;
   GtkColumnListItemFactory *factory;
+
+  GtkSorter *sorter;
 };
 
 struct _GtkColumnViewClass
@@ -69,6 +78,7 @@ enum
   PROP_HSCROLL_POLICY,
   PROP_MODEL,
   PROP_SHOW_SEPARATORS,
+  PROP_SORTER,
   PROP_VADJUSTMENT,
   PROP_VSCROLL_POLICY,
 
@@ -250,6 +260,8 @@ gtk_column_view_dispose (GObject *object)
   g_clear_pointer ((GtkWidget **) &self->listview, gtk_widget_unparent);
   g_clear_object (&self->factory);
 
+  g_clear_object (&self->sorter);
+
   G_OBJECT_CLASS (gtk_column_view_parent_class)->dispose (object);
 }
 
@@ -301,6 +313,10 @@ gtk_column_view_get_property (GObject    *object,
       g_value_set_enum (value, gtk_scrollable_get_vscroll_policy (GTK_SCROLLABLE (self->listview)));
       break;
 
+    case PROP_SORTER:
+      g_value_set_object (value, self->sorter);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -429,6 +445,18 @@ gtk_column_view_class_init (GtkColumnViewClass *klass)
                           FALSE,
                           G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
 
+  /**
+   * GtkColumnView:sorter:
+   *
+   * Sorter with the sorting choices of the user
+   */
+  properties[PROP_SORTER] =
+    g_param_spec_object ("sorter",
+                         P_("Sorter"),
+                         P_("Sorter with sorting choices of the user"),
+                         GTK_TYPE_SORTER,
+                         G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
   g_object_class_install_properties (gobject_class, N_PROPS, properties);
 
   /**
@@ -468,6 +496,7 @@ gtk_column_view_init (GtkColumnView *self)
   gtk_widget_set_layout_manager (self->header, gtk_column_view_layout_new (self));
   gtk_widget_set_parent (self->header, GTK_WIDGET (self));
 
+  self->sorter = gtk_column_view_sorter_new ();
   self->factory = gtk_column_list_item_factory_new (self);
   self->listview = GTK_LIST_VIEW (gtk_list_view_new_with_factory (
         GTK_LIST_ITEM_FACTORY (g_object_ref (self->factory))));
@@ -643,6 +672,7 @@ gtk_column_view_remove_column (GtkColumnView       *self,
         break;
     }
 
+  gtk_column_view_sorter_remove_column (GTK_COLUMN_VIEW_SORTER (self->sorter), column);
   gtk_column_view_column_set_column_view (column, NULL);
   g_list_store_remove (self->columns, i);
 }
@@ -681,3 +711,28 @@ gtk_column_view_get_header_widget (GtkColumnView *self)
   return GTK_LIST_ITEM_WIDGET (self->header);
 }
 
+/**
+ * gtk_column_view_get_sorter:
+ * @self: a #GtkColumnView
+ *
+ * Returns the sorter associated with users sorting choices in
+ * the column view.
+ *
+ * To allow users to customizable sorting by clicking on column
+ * headers, this sorter needs to be set on the sort
+ * model(s) underneath the model that is displayed
+ * by the view.
+ *
+ * See gtk_column_view_column_get_sorter() for setting up
+ * per-column sorting.
+ *
+ * Returns: (transfer none): the #GtkSorter of @self
+ */
+GtkSorter *
+gtk_column_view_get_sorter (GtkColumnView *self)
+{
+  g_return_val_if_fail (GTK_IS_COLUMN_VIEW (self), NULL);
+
+  return self->sorter;
+}
+
diff --git a/gtk/gtkcolumnview.h b/gtk/gtkcolumnview.h
index a4ac08a8b1..6ec91319e8 100644
--- a/gtk/gtkcolumnview.h
+++ b/gtk/gtkcolumnview.h
@@ -25,6 +25,8 @@
 #endif
 
 #include <gtk/gtktypes.h>
+#include <gtk/gtksortlistmodel.h>
+#include <gtk/gtksorter.h>
 
 G_BEGIN_DECLS
 
@@ -65,12 +67,16 @@ GListModel *    gtk_column_view_get_model                       (GtkColumnView
 GDK_AVAILABLE_IN_ALL
 void            gtk_column_view_set_model                       (GtkColumnView          *self,
                                                                  GListModel             *model);
+
 GDK_AVAILABLE_IN_ALL
 gboolean        gtk_column_view_get_show_separators             (GtkColumnView          *self);
 GDK_AVAILABLE_IN_ALL
 void            gtk_column_view_set_show_separators             (GtkColumnView          *self,
                                                                  gboolean                show_separators);
 
+GDK_AVAILABLE_IN_ALL
+GtkSorter *     gtk_column_view_get_sorter                      (GtkColumnView          *self);
+
 G_END_DECLS
 
 #endif  /* __GTK_COLUMN_VIEW_H__ */
diff --git a/gtk/gtkcolumnviewcolumn.c b/gtk/gtkcolumnviewcolumn.c
index c33c50cd53..de240b0d4e 100644
--- a/gtk/gtkcolumnviewcolumn.c
+++ b/gtk/gtkcolumnviewcolumn.c
@@ -20,6 +20,7 @@
 #include "config.h"
 
 #include "gtkcolumnviewcolumnprivate.h"
+#include "gtkcolumnviewsorterprivate.h"
 
 #include "gtkcolumnviewprivate.h"
 #include "gtkcolumnviewtitleprivate.h"
@@ -32,6 +33,7 @@
 #include "gtksizegroup.h"
 #include "gtkstylecontext.h"
 #include "gtkwidgetprivate.h"
+#include "gtksorter.h"
 
 /**
  * SECTION:gtkcolumnviewcolumn
@@ -48,6 +50,7 @@ struct _GtkColumnViewColumn
 
   GtkListItemFactory *factory;
   char *title;
+  GtkSorter *sorter;
 
   /* data for the view */
   GtkColumnView *view;
@@ -73,6 +76,7 @@ enum
   PROP_COLUMN_VIEW,
   PROP_FACTORY,
   PROP_TITLE,
+  PROP_SORTER,
 
   N_PROPS
 };
@@ -90,6 +94,7 @@ gtk_column_view_column_dispose (GObject *object)
   g_assert (self->first_cell == NULL); /* no view = no children */
 
   g_clear_object (&self->factory);
+  g_clear_object (&self->sorter);
   g_clear_pointer (&self->title, g_free);
 
   G_OBJECT_CLASS (gtk_column_view_column_parent_class)->dispose (object);
@@ -117,6 +122,10 @@ gtk_column_view_column_get_property (GObject    *object,
       g_value_set_string (value, self->title);
       break;
 
+    case PROP_SORTER:
+      g_value_set_object (value, self->sorter);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -141,6 +150,10 @@ gtk_column_view_column_set_property (GObject      *object,
       gtk_column_view_column_set_title (self, g_value_get_string (value));
       break;
 
+    case PROP_SORTER:
+      gtk_column_view_column_set_sorter (self, g_value_get_object (value));
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
       break;
@@ -192,6 +205,18 @@ gtk_column_view_column_class_init (GtkColumnViewColumnClass *klass)
                           NULL,
                           G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
 
+  /**
+   * GtkColumnViewColumn:sorter:
+   *
+   * Sorter for sorting items according to this column
+   */
+  properties[PROP_SORTER] =
+    g_param_spec_object ("sorter",
+                         P_("Sorter"),
+                         P_("Sorter for sorting items according to this column"),
+                         GTK_TYPE_SORTER,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
   g_object_class_install_properties (gobject_class, N_PROPS, properties);
 }
 
@@ -552,3 +577,73 @@ gtk_column_view_column_get_title (GtkColumnViewColumn *self)
   return self->title;
 }
 
+#if 0
+static void
+gtk_column_view_column_add_to_sorter (GtkColumnViewColumn *self)
+{
+  if (self->view == NULL)
+    return;
+  
+  gtk_column_view_sorter_add_column (GTK_COLUMN_VIEW_SORTER (gtk_column_view_get_sorter (self->view)), self);
+}
+#endif
+
+static void
+gtk_column_view_column_remove_from_sorter (GtkColumnViewColumn *self)
+{
+  if (self->view == NULL)
+    return;
+  
+  gtk_column_view_sorter_remove_column (GTK_COLUMN_VIEW_SORTER (gtk_column_view_get_sorter (self->view)), 
self);
+}
+
+/**
+ * gtk_column_view_column_set_sorter:
+ * @self: a #GtkColumnViewColumn
+ * @sorter: (nullable): the #GtkSorter to associate with @column
+ *
+ * Associates a sorter with the column.
+ *
+ * This sorter can be made active by clicking on the column
+ * header, or by calling gtk_column_view_sort_by_column().
+ */
+void
+gtk_column_view_column_set_sorter (GtkColumnViewColumn *self,
+                                   GtkSorter           *sorter)
+{
+  g_return_if_fail (GTK_IS_COLUMN_VIEW_COLUMN (self));
+  g_return_if_fail (sorter == NULL || GTK_IS_SORTER (sorter));
+
+  if (!g_set_object (&self->sorter, sorter))
+    return;
+
+  gtk_column_view_column_remove_from_sorter (self);
+
+  if (self->header)
+    gtk_column_view_title_update (GTK_COLUMN_VIEW_TITLE (self->header));
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SORTER]);
+}
+
+/**
+ * gtk_column_view_column_get_sorter:
+ * @self: a #GtkColumnViewColumn
+ *
+ * Returns the sorter that is associated with the column.
+ *
+ * Returns: (transfer none): the #GtkSorter of @self
+ */
+GtkSorter *
+gtk_column_view_column_get_sorter (GtkColumnViewColumn *self)
+{
+  g_return_val_if_fail (GTK_IS_COLUMN_VIEW_COLUMN (self), NULL);
+
+  return self->sorter;
+}
+
+void
+gtk_column_view_column_notify_sort (GtkColumnViewColumn *self)
+{
+  if (self->header)
+    gtk_column_view_title_update (GTK_COLUMN_VIEW_TITLE (self->header));
+}
diff --git a/gtk/gtkcolumnviewcolumn.h b/gtk/gtkcolumnviewcolumn.h
index 612cdb1854..f74cedaa08 100644
--- a/gtk/gtkcolumnviewcolumn.h
+++ b/gtk/gtkcolumnviewcolumn.h
@@ -25,6 +25,7 @@
 #endif
 
 #include <gtk/gtkcolumnview.h>
+#include <gtk/gtksorter.h>
 
 G_BEGIN_DECLS
 
@@ -65,6 +66,12 @@ void                    gtk_column_view_column_set_title                (GtkColu
 GDK_AVAILABLE_IN_ALL
 const char *            gtk_column_view_column_get_title                (GtkColumnViewColumn    *self);
 
+GDK_AVAILABLE_IN_ALL
+void                    gtk_column_view_column_set_sorter               (GtkColumnViewColumn    *self,
+                                                                         GtkSorter              *sorter);
+GDK_AVAILABLE_IN_ALL
+GtkSorter *             gtk_column_view_column_get_sorter               (GtkColumnViewColumn    *self);
+
 G_END_DECLS
 
 #endif  /* __GTK_COLUMN_VIEW_COLUMN_H__ */
diff --git a/gtk/gtkcolumnviewcolumnprivate.h b/gtk/gtkcolumnviewcolumnprivate.h
index d7e06a5b0f..fe46663e63 100644
--- a/gtk/gtkcolumnviewcolumnprivate.h
+++ b/gtk/gtkcolumnviewcolumnprivate.h
@@ -24,6 +24,7 @@
 
 #include "gtk/gtkcolumnviewcellprivate.h"
 
+
 void                    gtk_column_view_column_set_column_view          (GtkColumnViewColumn    *self,
                                                                          GtkColumnView          *view);
 
@@ -44,4 +45,6 @@ void                    gtk_column_view_column_get_allocation           (GtkColu
                                                                          int                    *offset,
                                                                          int                    *size);
 
+void                    gtk_column_view_column_notify_sort              (GtkColumnViewColumn    *self);
+
 #endif  /* __GTK_COLUMN_VIEW_COLUMN_PRIVATE_H__ */
diff --git a/gtk/gtkcolumnviewprivate.h b/gtk/gtkcolumnviewprivate.h
index c356fae508..0d5cbbeed6 100644
--- a/gtk/gtkcolumnviewprivate.h
+++ b/gtk/gtkcolumnviewprivate.h
@@ -22,6 +22,7 @@
 
 #include "gtk/gtkcolumnview.h"
 
+#include "gtk/gtkcolumnviewsorterprivate.h"
 #include "gtk/gtklistitemwidgetprivate.h"
 
 GtkListItemWidget *     gtk_column_view_get_header_widget       (GtkColumnView          *self);
diff --git a/gtk/gtkcolumnviewsorter.c b/gtk/gtkcolumnviewsorter.c
new file mode 100644
index 0000000000..d431de0cb7
--- /dev/null
+++ b/gtk/gtkcolumnviewsorter.c
@@ -0,0 +1,282 @@
+/*
+ * Copyright © 2019 Matthias Clasen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen <mclasen redhat com>
+ */
+
+#include "config.h"
+
+#include "gtkcolumnviewsorterprivate.h"
+
+#include "gtkcolumnviewcolumnprivate.h"
+#include "gtkintl.h"
+#include "gtktypebuiltins.h"
+
+typedef struct
+{
+  GtkColumnViewColumn *column;
+  GtkSorter *sorter;
+  gboolean   inverted;
+  gulong     changed_id;
+} Sorter;
+ 
+static void
+free_sorter (gpointer data)
+{
+  Sorter *s = data;
+
+  g_signal_handler_disconnect (s->sorter, s->changed_id);
+  g_object_unref (s->sorter);
+  g_object_unref (s->column);
+  g_free (s);
+}
+
+struct _GtkColumnViewSorter
+{
+  GtkSorter parent_instance;
+
+  GSequence *sorters;
+};
+
+G_DEFINE_TYPE (GtkColumnViewSorter, gtk_column_view_sorter, GTK_TYPE_SORTER)
+
+static GtkOrdering
+gtk_column_view_sorter_compare (GtkSorter *sorter,
+                                gpointer   item1,
+                                gpointer   item2)
+{
+  GtkColumnViewSorter *self = GTK_COLUMN_VIEW_SORTER (sorter);
+  GtkOrdering result = GTK_ORDERING_EQUAL;
+  GSequenceIter *iter;
+
+  for (iter = g_sequence_get_begin_iter (self->sorters);
+       !g_sequence_iter_is_end (iter);
+       iter = g_sequence_iter_next (iter))
+    {
+      Sorter *s = g_sequence_get (iter);
+
+      result = gtk_sorter_compare (s->sorter, item1, item2);
+      if (s->inverted)
+        result = - result;
+
+      if (result != GTK_ORDERING_EQUAL)
+        break;
+    }
+
+  return result;
+}
+
+static GtkSorterOrder
+gtk_column_view_sorter_get_order (GtkSorter *sorter)
+{
+  GtkColumnViewSorter *self = GTK_COLUMN_VIEW_SORTER (sorter);
+  GtkSorterOrder result = GTK_SORTER_ORDER_NONE;
+  GSequenceIter *iter;
+
+  for (iter = g_sequence_get_begin_iter (self->sorters);
+       !g_sequence_iter_is_end (iter);
+       iter = g_sequence_iter_next (iter))
+    {
+      Sorter *s = g_sequence_get (iter);
+
+      switch (gtk_sorter_get_order (s->sorter))
+        {
+          case GTK_SORTER_ORDER_PARTIAL:
+            result = GTK_SORTER_ORDER_PARTIAL;
+            break;
+          case GTK_SORTER_ORDER_NONE:
+            break;
+          case GTK_SORTER_ORDER_TOTAL:
+            return GTK_SORTER_ORDER_TOTAL;
+          default:
+            g_assert_not_reached ();
+            break;
+        }
+    }
+
+  return result;
+}
+
+static void
+gtk_column_view_sorter_dispose (GObject *object)
+{
+  GtkColumnViewSorter *self = GTK_COLUMN_VIEW_SORTER (object);
+
+  g_clear_pointer (&self->sorters, g_sequence_free);
+
+  G_OBJECT_CLASS (gtk_column_view_sorter_parent_class)->dispose (object);
+}
+
+static void
+gtk_column_view_sorter_class_init (GtkColumnViewSorterClass *class)
+{
+  GtkSorterClass *sorter_class = GTK_SORTER_CLASS (class);
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+
+  sorter_class->compare = gtk_column_view_sorter_compare;
+  sorter_class->get_order = gtk_column_view_sorter_get_order;
+
+  object_class->dispose = gtk_column_view_sorter_dispose;
+}
+
+static void
+gtk_column_view_sorter_init (GtkColumnViewSorter *self)
+{
+  self->sorters = g_sequence_new (free_sorter);
+}
+
+GtkSorter *
+gtk_column_view_sorter_new (void)
+{
+  return g_object_new (GTK_TYPE_COLUMN_VIEW_SORTER, NULL);
+}
+
+static void
+gtk_column_view_sorter_changed_cb (GtkSorter *sorter, int change, gpointer data)
+{
+  gtk_sorter_changed (GTK_SORTER (data), GTK_SORTER_CHANGE_DIFFERENT);
+}
+
+static gboolean
+remove_column (GtkColumnViewSorter *self,
+               GtkColumnViewColumn *column)
+{
+  GSequenceIter *iter;
+
+  for (iter = g_sequence_get_begin_iter (self->sorters);
+       !g_sequence_iter_is_end (iter);
+       iter = g_sequence_iter_next (iter))
+    {
+      Sorter *s = g_sequence_get (iter);
+
+      if (s->column == column)
+        {
+          g_sequence_remove (iter);
+          return TRUE;
+        }
+    }
+
+  return FALSE;
+}
+
+gboolean
+gtk_column_view_sorter_add_column (GtkColumnViewSorter *self,
+                                   GtkColumnViewColumn *column)
+{
+  GSequenceIter *iter;
+  GtkSorter *sorter;
+  Sorter *s, *first;
+
+  g_return_val_if_fail (GTK_IS_COLUMN_VIEW_SORTER (self), FALSE);
+  g_return_val_if_fail (GTK_IS_COLUMN_VIEW_COLUMN (column), FALSE);
+
+  sorter = gtk_column_view_column_get_sorter (column);
+  if (sorter == NULL)
+    return FALSE;
+
+  iter = g_sequence_get_begin_iter (self->sorters);
+  if (!g_sequence_iter_is_end (iter))
+    {
+      first = g_sequence_get (iter);
+      if (first->column == column)
+        {
+          first->inverted = !first->inverted;
+          goto out;
+        }
+    }
+  else
+    first = NULL;
+
+  remove_column (self, column);
+
+  s = g_new (Sorter, 1);
+  s->column = g_object_ref (column);
+  s->sorter = g_object_ref (sorter);
+  s->changed_id = g_signal_connect (sorter, "changed", G_CALLBACK (gtk_column_view_sorter_changed_cb), self);
+  s->inverted = FALSE;
+ 
+  g_sequence_insert_before (iter, s);
+
+  /* notify the previous first column to stop drawing an arrow */
+  if (first)
+    gtk_column_view_column_notify_sort (first->column);
+
+out:
+  gtk_sorter_changed (GTK_SORTER (self), GTK_SORTER_CHANGE_DIFFERENT);
+
+  gtk_column_view_column_notify_sort (column);
+
+  return TRUE;
+}
+
+gboolean
+gtk_column_view_sorter_remove_column (GtkColumnViewSorter *self,
+                                      GtkColumnViewColumn *column)
+{
+  g_return_val_if_fail (GTK_IS_COLUMN_VIEW_SORTER (self), FALSE);
+  g_return_val_if_fail (GTK_IS_COLUMN_VIEW_COLUMN (column), FALSE);
+
+  if (remove_column (self, column))
+    {
+      gtk_sorter_changed (GTK_SORTER (self), GTK_SORTER_CHANGE_DIFFERENT);
+      gtk_column_view_column_notify_sort (column);
+      return TRUE;
+    }
+
+  return FALSE;
+}
+
+void
+gtk_column_view_sorter_clear (GtkColumnViewSorter *self)
+{
+  GSequenceIter *iter;
+  Sorter *s;
+  GtkColumnViewColumn *column;
+
+  g_return_if_fail (GTK_IS_COLUMN_VIEW_SORTER (self));
+
+  if (g_sequence_is_empty (self->sorters))
+    return;
+
+  iter = g_sequence_get_begin_iter (self->sorters);
+  s = g_sequence_get (iter);
+  column = s->column;
+  g_sequence_remove_range (iter, g_sequence_get_end_iter (self->sorters));
+
+  gtk_sorter_changed (GTK_SORTER (self), GTK_SORTER_CHANGE_DIFFERENT);
+
+  gtk_column_view_column_notify_sort (column);
+}
+
+GtkColumnViewColumn *
+gtk_column_view_sorter_get_sort_column (GtkColumnViewSorter *self,
+                                        gboolean            *inverted)
+{
+  GSequenceIter *iter;
+  Sorter *s;
+
+  g_return_val_if_fail (GTK_IS_COLUMN_VIEW_SORTER (self), NULL);
+
+  if (g_sequence_is_empty (self->sorters))
+    return NULL;
+
+  iter = g_sequence_get_begin_iter (self->sorters);
+  s = g_sequence_get (iter);
+
+  *inverted = s->inverted;
+
+  return s->column;
+}
diff --git a/gtk/gtkcolumnviewsorterprivate.h b/gtk/gtkcolumnviewsorterprivate.h
new file mode 100644
index 0000000000..ce89952170
--- /dev/null
+++ b/gtk/gtkcolumnviewsorterprivate.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright © 2019 Matthias Clasen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen <mclasen redhat com>
+ */
+
+#ifndef __GTK_COLUMN_VIEW_SORTER_H__
+#define __GTK_COLUMN_VIEW_SORTER_H__
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gdk/gdk.h>
+#include <gtk/gtksorter.h>
+#include <gtk/gtkcolumnviewcolumn.h>
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_COLUMN_VIEW_SORTER             (gtk_column_view_sorter_get_type ())
+
+G_DECLARE_FINAL_TYPE (GtkColumnViewSorter, gtk_column_view_sorter, GTK, COLUMN_VIEW_SORTER, GtkSorter)
+
+GtkSorter *             gtk_column_view_sorter_new              (void);
+
+gboolean                gtk_column_view_sorter_add_column       (GtkColumnViewSorter    *self,
+                                                                 GtkColumnViewColumn    *column);
+gboolean                gtk_column_view_sorter_remove_column    (GtkColumnViewSorter    *self,
+                                                                 GtkColumnViewColumn    *column);
+
+void                    gtk_column_view_sorter_clear            (GtkColumnViewSorter    *self);
+
+GtkColumnViewColumn *   gtk_column_view_sorter_get_sort_column  (GtkColumnViewSorter    *self,
+                                                                 gboolean               *inverted);
+
+
+G_END_DECLS
+
+#endif /* __GTK_SORTER_H__ */
+
diff --git a/gtk/meson.build b/gtk/meson.build
index 72b8e8d592..54907748aa 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -199,6 +199,7 @@ gtk_public_sources = files([
   'gtkcolorutils.c',
   'gtkcolumnview.c',
   'gtkcolumnviewcolumn.c',
+  'gtkcolumnviewsorter.c',
   'gtkcombobox.c',
   'gtkcomboboxtext.c',
   'gtkcomposetable.c',
diff --git a/testsuite/gtk/defaultvalue.c b/testsuite/gtk/defaultvalue.c
index d22e5f8a12..a48ee49eb0 100644
--- a/testsuite/gtk/defaultvalue.c
+++ b/testsuite/gtk/defaultvalue.c
@@ -240,7 +240,8 @@ test_type (gconstpointer data)
        continue;
 
       if (g_type_is_a (type, GTK_TYPE_COLUMN_VIEW) &&
-         strcmp (pspec->name, "columns") == 0)
+          (strcmp (pspec->name, "columns") == 0 ||
+          strcmp (pspec->name, "sorter") == 0))
        continue;
 
 G_GNUC_BEGIN_IGNORE_DEPRECATIONS