[gtk/wip/otte/sortlistmodel: 28/39] Add a custom model using quicksort

[Benjamin Otte <otte src gnome org>]

commit b12337a74410ab77aa58d4f1864b60a7af8e5411
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jul 7 17:47:36 2020 -0400

    Add a custom model using quicksort

 gtk/gtk.h              |   1 +
 gtk/gtksor3listmodel.c | 593 +++++++++++++++++++++++++++++++++++++++++++++++++
 gtk/gtksor3listmodel.h |  57 +++++
 gtk/meson.build        |   2 +
 4 files changed, 653 insertions(+)
---
diff --git a/gtk/gtk.h b/gtk/gtk.h
index f19db0664a..d01643e52a 100644
--- a/gtk/gtk.h
+++ b/gtk/gtk.h
@@ -235,6 +235,7 @@
 #include <gtk/gtksnapshot.h>
 #include <gtk/gtksorter.h>
 #include <gtk/gtksor2listmodel.h>
+#include <gtk/gtksor3listmodel.h>
 #include <gtk/gtksor4listmodel.h>
 #include <gtk/gtksor5listmodel.h>
 #include <gtk/gtksortlistmodel.h>
diff --git a/gtk/gtksor3listmodel.c b/gtk/gtksor3listmodel.c
new file mode 100644
index 0000000000..716ec2ab15
--- /dev/null
+++ b/gtk/gtksor3listmodel.c
@@ -0,0 +1,593 @@
+/*
+ * Copyright © 2018 Benjamin Otte
+ *
+ * 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: Benjamin Otte <otte gnome org>
+ */
+
+#include "config.h"
+
+#include "gtksor3listmodel.h"
+
+#include "gtkintl.h"
+#include "gtkprivate.h"
+
+#define GDK_ARRAY_ELEMENT_TYPE GObject *
+#define GDK_ARRAY_TYPE_NAME SortArray
+#define GDK_ARRAY_NAME sort_array
+#define GDK_ARRAY_FREE_FUNC g_object_unref
+#define GDK_ARRAY_PREALLOC 16
+#include "gdk/gdkarrayimpl.c"
+
+#define GDK_ARRAY_ELEMENT_TYPE guint
+#define GDK_ARRAY_TYPE_NAME PivotStack
+#define GDK_ARRAY_NAME pivot_stack
+#define GDK_ARRAY_BY_VALUE
+#define GDK_ARRAY_PREALLOC 16
+#include "gdk/gdkarrayimpl.c"
+
+static inline void
+pivot_stack_push (PivotStack *stack,
+                  guint       pos)
+{
+  gsize size = pivot_stack_get_size (stack);
+  pivot_stack_set_size (stack, size + 1);
+  *pivot_stack_get (stack, size) = pos;
+}
+
+static inline guint
+pivot_stack_top (PivotStack *stack)
+{
+  return *pivot_stack_get (stack, pivot_stack_get_size (stack) - 1);
+}
+
+static inline guint
+pivot_stack_pop (PivotStack *stack)
+{
+  gsize size = pivot_stack_get_size (stack);
+  guint top = *pivot_stack_get (stack, size - 1);
+  pivot_stack_set_size (stack, size - 1);
+  return top;
+}
+
+/**
+ * SECTION:gtksor3listmodel
+ * @title: GtkSor3ListModel
+ * @short_description: A list model that sorts its items
+ * @see_also: #GListModel, #GtkSorter
+ *
+ * #GtkSor3ListModel is a list model that takes a list model and
+ * sorts its elements according to a #GtkSorter.
+ *
+ * #GtkSor3ListModel is a generic model and because of that it
+ * cannot take advantage of any external knowledge when sorting.
+ * If you run into performance issues with #GtkSor3ListModel, it
+ * is strongly recommended that you write your own sorting list
+ * model.
+ */
+
+enum {
+  PROP_0,
+  PROP_MODEL,
+  PROP_SORTER,
+  NUM_PROPERTIES
+};
+
+struct _GtkSor3ListModel
+{
+  GObject parent_instance;
+
+  GListModel *model;
+  GtkSorter *sorter;
+
+  SortArray items; /* empty if known unsorted */
+
+  guint sorting_cb;
+  guint sorted_to;
+  PivotStack stack;
+};
+
+struct _GtkSor3ListModelClass
+{
+  GObjectClass parent_class;
+};
+
+static GParamSpec *properties[NUM_PROPERTIES] = { NULL, };
+
+static GType
+gtk_sor3_list_model_get_item_type (GListModel *list)
+{
+  return G_TYPE_OBJECT;
+}
+
+static guint
+gtk_sor3_list_model_get_n_items (GListModel *list)
+{
+  GtkSor3ListModel *self = GTK_SOR3_LIST_MODEL (list);
+
+  if (self->model == NULL)
+    return 0;
+
+  return g_list_model_get_n_items (self->model);
+}
+
+static gpointer
+gtk_sor3_list_model_get_item (GListModel *list,
+                              guint       position)
+{
+  GtkSor3ListModel *self = GTK_SOR3_LIST_MODEL (list);
+
+  if (self->model == NULL)
+    return NULL;
+
+  if (sort_array_is_empty (&self->items))
+    return g_list_model_get_item (self->model, position);
+
+  if (position >= sort_array_get_size (&self->items))
+    return NULL;
+
+  return g_object_ref (sort_array_get (&self->items, position));
+}
+
+static void
+gtk_sor3_list_model_model_init (GListModelInterface *iface)
+{
+  iface->get_item_type = gtk_sor3_list_model_get_item_type;
+  iface->get_n_items = gtk_sor3_list_model_get_n_items;
+  iface->get_item = gtk_sor3_list_model_get_item;
+}
+
+G_DEFINE_TYPE_WITH_CODE (GtkSor3ListModel, gtk_sor3_list_model, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, gtk_sor3_list_model_model_init))
+
+static void
+gtk_sor3_list_model_clear_items (GtkSor3ListModel *self)
+{
+  sort_array_clear (&self->items);
+}
+
+static void
+gtk_sor3_list_model_create_items (GtkSor3ListModel *self)
+{
+  guint i, n_items;
+
+  if (self->sorter == NULL ||
+      self->model == NULL ||
+      gtk_sorter_get_order (self->sorter) == GTK_SORTER_ORDER_NONE)
+    return;
+
+  n_items = g_list_model_get_n_items (self->model);
+  sort_array_reserve (&self->items, n_items);
+  for (i = 0; i < n_items; i++)
+    sort_array_append (&self->items, g_list_model_get_item (self->model, i));
+}
+
+static void
+gtk_sor3_list_model_stop_sorting (GtkSor3ListModel *self)
+{
+  g_clear_handle_id (&self->sorting_cb, g_source_remove);
+  pivot_stack_set_size (&self->stack, 0);
+}
+
+static inline int
+compare (GtkSorter *sorter, GObject *a, GObject *b)
+{
+  return gtk_sorter_compare (sorter, a, b);
+}
+
+static inline void
+swap (SortArray *items, guint i, guint j)
+{
+  GObject *tmp = sort_array_get (items, i);
+  *sort_array_index (items, i) = sort_array_get (items, j);
+  *sort_array_index (items, j) = tmp;
+}
+
+/* This is pretty much the incremental quicksort that is described
+ * in the wikipedia article about it. Calling iqs repeatedly for
+ * each position from 0..k gives you that k smallest elements, in
+ * order. Which is what we do. As a side-effect, the array ends up
+ * getting sorted. The nice thing is that we simply remember how
+ * far we've enumerated (in sorted_to), and interrupt the sorting,
+ * which is the incremental part.
+ */
+static guint
+partition (SortArray *items, guint first, guint end, GtkSorter *sorter)
+{
+  guint mid;
+  guint i, j;
+  GObject *pivot;
+
+  mid = first + (end - first) / 2;
+  if (compare (sorter, sort_array_get (items, mid),
+                       sort_array_get (items, first)) < 0)
+      swap (items, mid, first);
+  if (compare (sorter, sort_array_get (items, end),
+                       sort_array_get (items, first)) < 0)
+      swap (items, end, first);
+  if (compare (sorter, sort_array_get (items, mid),
+                       sort_array_get (items, end)) < 0)
+      swap (items, mid, end);
+
+  pivot = sort_array_get (items, end);
+
+  i = first;
+  j = end;
+  while (1)
+    {
+      while (compare (sorter, sort_array_get (items, i), pivot) < 0) i++;
+      while (j > i && compare (sorter, sort_array_get (items, j), pivot) >= 0) j--;
+      if (i >= j) return j;
+      swap (items, i, j);
+    }
+
+  return j;
+}
+
+static gpointer
+iqs (SortArray *items, guint pos, PivotStack *stack, GtkSorter *sorter)
+{
+  guint top;
+  guint pivot;
+
+  top = pivot_stack_top (stack);
+  if (top == pos)
+    {
+      pivot_stack_pop (stack);
+      return sort_array_get (items, pos);
+    }
+
+  pivot = partition (items, pos, top, sorter);
+  pivot_stack_push (stack, pivot);
+
+  return iqs (items, pos, stack, sorter);
+}
+
+static gboolean
+gtk_sor3_list_model_sort_cb (gpointer data)
+{
+  GtkSor3ListModel *self = GTK_SOR3_LIST_MODEL (data);
+  guint start;
+  guint end;
+  guint n_items;
+  guint i;
+
+  start = self->sorted_to;
+  n_items = sort_array_get_size (&self->items);
+  end = MIN (512, n_items - start);
+
+  for (i = 0; i < end; i++)
+    {
+      iqs (&self->items, self->sorted_to, &self->stack, self->sorter);
+      self->sorted_to++;
+    }
+
+  if (self->sorted_to >= n_items)
+    gtk_sor3_list_model_stop_sorting (self);
+
+  g_list_model_items_changed (G_LIST_MODEL (self), start, n_items - start, n_items - start);
+
+  return G_SOURCE_CONTINUE;
+}
+
+static void
+gtk_sor3_list_model_start_sorting (GtkSor3ListModel *self)
+{
+  if (sort_array_get_size (&self->items) == 0)
+    return;
+
+  g_assert (pivot_stack_get_size (&self->stack) == 0);
+  g_assert (self->sorting_cb == 0);
+
+  pivot_stack_push (&self->stack, (guint)sort_array_get_size (&self->items) - 1);
+  self->sorted_to = 0;
+
+  self->sorting_cb = g_idle_add (gtk_sor3_list_model_sort_cb, self);
+  g_source_set_name_by_id (self->sorting_cb, "[gtk] gtk_sor3_list_model_sort_cb");
+}
+
+static void
+gtk_sor3_list_model_resort (GtkSor3ListModel *self)
+{
+  gtk_sor3_list_model_stop_sorting (self);
+  gtk_sor3_list_model_start_sorting (self);
+}
+
+static void
+gtk_sor3_list_model_items_changed_cb (GListModel       *model,
+                                      guint             position,
+                                      guint             removed,
+                                      guint             added,
+                                      GtkSor3ListModel *self)
+{
+  guint n_items;
+
+  /* doesn't free() the array */
+  sort_array_set_size (&self->items, 0);
+  gtk_sor3_list_model_create_items (self);
+  gtk_sor3_list_model_resort (self);
+
+  n_items = g_list_model_get_n_items (model);
+  g_list_model_items_changed (G_LIST_MODEL (self), 0, n_items - added + removed, n_items);
+}
+
+static void
+gtk_sor3_list_model_set_property (GObject      *object,
+                                  guint         prop_id,
+                                  const GValue *value,
+                                  GParamSpec   *pspec)
+{
+  GtkSor3ListModel *self = GTK_SOR3_LIST_MODEL (object);
+
+  switch (prop_id)
+    {
+    case PROP_MODEL:
+      gtk_sor3_list_model_set_model (self, g_value_get_object (value));
+      break;
+
+    case PROP_SORTER:
+      gtk_sor3_list_model_set_sorter (self, g_value_get_object (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_sor3_list_model_get_property (GObject     *object,
+                                  guint        prop_id,
+                                  GValue      *value,
+                                  GParamSpec  *pspec)
+{
+  GtkSor3ListModel *self = GTK_SOR3_LIST_MODEL (object);
+
+  switch (prop_id)
+    {
+    case PROP_MODEL:
+      g_value_set_object (value, self->model);
+      break;
+
+    case PROP_SORTER:
+      g_value_set_object (value, self->sorter);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_sor3_list_model_sorter_changed_cb (GtkSorter        *sorter,
+                                       int               change,
+                                       GtkSor3ListModel *self)
+{
+  guint n_items;
+
+  if (gtk_sorter_get_order (sorter) == GTK_SORTER_ORDER_NONE)
+    gtk_sor3_list_model_clear_items (self);
+  else if (sort_array_is_empty (&self->items))
+    gtk_sor3_list_model_create_items (self);
+
+  gtk_sor3_list_model_resort (self);
+
+  n_items = g_list_model_get_n_items (G_LIST_MODEL (self));
+  if (n_items > 1)
+    g_list_model_items_changed (G_LIST_MODEL (self), 0, n_items, n_items);
+}
+
+static void
+gtk_sor3_list_model_clear_model (GtkSor3ListModel *self)
+{
+  if (self->model == NULL)
+    return;
+
+  g_signal_handlers_disconnect_by_func (self->model, gtk_sor3_list_model_items_changed_cb, self);
+  g_clear_object (&self->model);
+  gtk_sor3_list_model_stop_sorting (self);
+  gtk_sor3_list_model_clear_items (self);
+}
+
+static void
+gtk_sor3_list_model_clear_sorter (GtkSor3ListModel *self)
+{
+  if (self->sorter == NULL)
+    return;
+
+  g_signal_handlers_disconnect_by_func (self->sorter, gtk_sor3_list_model_sorter_changed_cb, self);
+  g_clear_object (&self->sorter);
+  gtk_sor3_list_model_stop_sorting (self);
+  gtk_sor3_list_model_clear_items (self);
+}
+
+static void
+gtk_sor3_list_model_dispose (GObject *object)
+{
+  GtkSor3ListModel *self = GTK_SOR3_LIST_MODEL (object);
+
+  gtk_sor3_list_model_stop_sorting (self);
+  gtk_sor3_list_model_clear_model (self);
+  gtk_sor3_list_model_clear_sorter (self);
+
+  G_OBJECT_CLASS (gtk_sor3_list_model_parent_class)->dispose (object);
+};
+
+static void
+gtk_sor3_list_model_class_init (GtkSor3ListModelClass *class)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (class);
+
+  gobject_class->set_property = gtk_sor3_list_model_set_property;
+  gobject_class->get_property = gtk_sor3_list_model_get_property;
+  gobject_class->dispose = gtk_sor3_list_model_dispose;
+
+  /**
+   * GtkSor3ListModel:sorter:
+   *
+   * The sorter for this model
+   */
+  properties[PROP_SORTER] =
+      g_param_spec_object ("sorter",
+                            P_("Sorter"),
+                            P_("The sorter for this model"),
+                            GTK_TYPE_SORTER,
+                            GTK_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkSor3ListModel:model:
+   *
+   * The model being sorted
+   */
+  properties[PROP_MODEL] =
+      g_param_spec_object ("model",
+                           P_("Model"),
+                           P_("The model being sorted"),
+                           G_TYPE_LIST_MODEL,
+                           GTK_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
+  g_object_class_install_properties (gobject_class, NUM_PROPERTIES, properties);
+}
+
+static void
+gtk_sor3_list_model_init (GtkSor3ListModel *self)
+{
+}
+
+/**
+ * gtk_sor3_list_model_new:
+ * @model: (allow-none): the model to sort
+ * @sorter: (allow-none): the #GtkSorter to sort @model with
+ *
+ * Creates a new sort list model that uses the @sorter to sort @model.
+ *
+ * Returns: a new #GtkSor3ListModel
+ **/
+GtkSor3ListModel *
+gtk_sor3_list_model_new (GListModel *model,
+                         GtkSorter  *sorter)
+{
+  GtkSor3ListModel *result;
+
+  g_return_val_if_fail (model == NULL || G_IS_LIST_MODEL (model), NULL);
+  g_return_val_if_fail (sorter == NULL || GTK_IS_SORTER (sorter), NULL);
+
+  result = g_object_new (GTK_TYPE_SOR3_LIST_MODEL,
+                         "model", model,
+                         "sorter", sorter,
+                         NULL);
+
+  return result;
+}
+
+/**
+ * gtk_sor3_list_model_set_model:
+ * @self: a #GtkSor3ListModel
+ * @model: (allow-none): The model to be sorted
+ *
+ * Sets the model to be sorted. The @model's item type must conform to
+ * the item type of @self.
+ **/
+void
+gtk_sor3_list_model_set_model (GtkSor3ListModel *self,
+                               GListModel       *model)
+{
+  guint removed, added;
+
+  g_return_if_fail (GTK_IS_SOR3_LIST_MODEL (self));
+  g_return_if_fail (model == NULL || G_IS_LIST_MODEL (model));
+
+  if (self->model == model)
+    return;
+
+  removed = g_list_model_get_n_items (G_LIST_MODEL (self));
+  gtk_sor3_list_model_clear_model (self);
+
+  if (model)
+    {
+      self->model = g_object_ref (model);
+      g_signal_connect (model, "items-changed", G_CALLBACK (gtk_sor3_list_model_items_changed_cb), self);
+      added = g_list_model_get_n_items (model);
+
+      gtk_sor3_list_model_create_items (self);
+      gtk_sor3_list_model_resort (self);
+    }
+  else
+    added = 0;
+  
+  if (removed > 0 || added > 0)
+    g_list_model_items_changed (G_LIST_MODEL (self), 0, removed, added);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MODEL]);
+}
+
+/**
+ * gtk_sor3_list_model_get_model:
+ * @self: a #GtkSor3ListModel
+ *
+ * Gets the model currently sorted or %NULL if none.
+ *
+ * Returns: (nullable) (transfer none): The model that gets sorted
+ **/
+GListModel *
+gtk_sor3_list_model_get_model (GtkSor3ListModel *self)
+{
+  g_return_val_if_fail (GTK_IS_SOR3_LIST_MODEL (self), NULL);
+
+  return self->model;
+}
+
+/**
+ * gtk_sor3_list_model_set_sorter:
+ * @self: a #GtkSor3ListModel
+ * @sorter: (allow-none): the #GtkSorter to sort @model with
+ *
+ * Sets a new sorter on @self.
+ */
+void
+gtk_sor3_list_model_set_sorter (GtkSor3ListModel *self,
+                                GtkSorter        *sorter)
+{
+  g_return_if_fail (GTK_IS_SOR3_LIST_MODEL (self));
+  g_return_if_fail (sorter == NULL || GTK_IS_SORTER (sorter));
+
+  gtk_sor3_list_model_clear_sorter (self);
+
+  if (sorter)
+    {
+      self->sorter = g_object_ref (sorter);
+      g_signal_connect (sorter, "changed", G_CALLBACK (gtk_sor3_list_model_sorter_changed_cb), self);
+      gtk_sor3_list_model_sorter_changed_cb (sorter, GTK_SORTER_CHANGE_DIFFERENT, self);
+    }
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SORTER]);
+}
+
+/**
+ * gtk_sor3_list_model_get_sorter:
+ * @self: a #GtkSor3LisTModel
+ *
+ * Gets the sorter that is used to sort @self.
+ *
+ * Returns: (nullable) (transfer none): the sorter of #self
+ */
+GtkSorter *
+gtk_sor3_list_model_get_sorter (GtkSor3ListModel *self)
+{
+  g_return_val_if_fail (GTK_IS_SOR3_LIST_MODEL (self), NULL);
+
+  return self->sorter;
+}
diff --git a/gtk/gtksor3listmodel.h b/gtk/gtksor3listmodel.h
new file mode 100644
index 0000000000..196693d585
--- /dev/null
+++ b/gtk/gtksor3listmodel.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright © 2018 Benjamin Otte
+ *
+ * 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: Benjamin Otte <otte gnome org>
+ */
+
+#ifndef __GTK_SOR3_LIST_MODEL_H__
+#define __GTK_SOR3_LIST_MODEL_H__
+
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gio/gio.h>
+#include <gtk/gtkwidget.h>
+#include <gtk/gtksorter.h>
+
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_SOR3_LIST_MODEL (gtk_sor3_list_model_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_FINAL_TYPE (GtkSor3ListModel, gtk_sor3_list_model, GTK, SOR3_LIST_MODEL, GObject)
+
+GDK_AVAILABLE_IN_ALL
+GtkSor3ListModel *      gtk_sor3_list_model_new                 (GListModel            *model,
+                                                                 GtkSorter             *sorter);
+GDK_AVAILABLE_IN_ALL
+void                    gtk_sor3_list_model_set_sorter          (GtkSor3ListModel       *self,
+                                                                 GtkSorter              *sorter);
+GDK_AVAILABLE_IN_ALL
+GtkSorter *             gtk_sor3_list_model_get_sorter          (GtkSor3ListModel       *self);
+
+GDK_AVAILABLE_IN_ALL
+void                    gtk_sor3_list_model_set_model           (GtkSor3ListModel       *self,
+                                                                 GListModel             *model);
+GDK_AVAILABLE_IN_ALL
+GListModel *            gtk_sor3_list_model_get_model           (GtkSor3ListModel       *self);
+
+G_END_DECLS
+
+#endif /* __GTK_SOR3_LIST_MODEL_H__ */
diff --git a/gtk/meson.build b/gtk/meson.build
index a9dda4770d..84ddc9ea54 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -373,6 +373,7 @@ gtk_public_sources = files([
   'gtksnapshot.c',
   'gtksorter.c',
   'gtksor2listmodel.c',
+  'gtksor3listmodel.c',
   'gtksor4listmodel.c',
   'gtksor5listmodel.c',
   'gtksortlistmodel.c',
@@ -650,6 +651,7 @@ gtk_public_headers = files([
   'gtksnapshot.h',
   'gtksorter.h',
   'gtksor2listmodel.h',
+  'gtksor3listmodel.h',
   'gtksor4listmodel.h',
   'gtksor5listmodel.h',
   'gtksortlistmodel.h',