Add GtkDirectoryList

Adds a new listmodel called GtkDirectoryList that lists the children of
a GFile as GFileInfos.

This is supposed to be used by the filechooser.

7 files changed, 777 insertions, 0 deletions

diff --git a/docs/reference/gtk/gtk4-docs.xml b/docs/reference/gtk/gtk4-docs.xml
index 7d9321bb1b..22e5fa0c82 100644
--- a/docs/reference/gtk/gtk4-docs.xml
+++ b/docs/reference/gtk/gtk4-docs.xml
@@ -56,6 +56,7 @@
       <xi:include href="xml/gtkselectionmodel.xml" />
       <xi:include href="xml/gtknoselection.xml" />
       <xi:include href="xml/gtksingleselection.xml" />
+      <xi:include href="xml/gtkdirectorylist.xml" />
     </chapter>
 
     <chapter id="Trees">
diff --git a/docs/reference/gtk/gtk4-sections.txt b/docs/reference/gtk/gtk4-sections.txt
index 97d20ece0b..d519009a94 100644
--- a/docs/reference/gtk/gtk4-sections.txt
+++ b/docs/reference/gtk/gtk4-sections.txt
@@ -1161,6 +1161,30 @@ gtk_file_filter_get_type
 </SECTION>
 
 <SECTION>
+<FILE>gtkdirectorylist</FILE>
+<TITLE>GtkDirectoryList</TITLE>
+GtkDirectoryList
+gtk_directory_list_new
+gtk_directory_list_get_attributes
+gtk_directory_list_set_attributes
+gtk_directory_list_get_file
+gtk_directory_list_set_file
+gtk_directory_list_get_io_priority
+gtk_directory_list_set_io_priority
+gtk_directory_list_is_loading
+gtk_directory_list_get_error
+<SUBSECTION Standard>
+GTK_DIRECTORY_LIST
+GTK_IS_DIRECTORY_LIST
+GTK_TYPE_DIRECTORY_LIST
+GTK_DIRECTORY_LIST_CLASS
+GTK_IS_DIRECTORY_LIST_CLASS
+GTK_DIRECTORY_LIST_GET_CLASS
+<SUBSECTION Private>
+gtk_directory_list_get_type
+</SECTION>
+
+<SECTION>
 <FILE>gtkfilterlistmodel</FILE>
 <TITLE>GtkFilterListModel</TITLE>
 GtkFilterListModel
diff --git a/docs/reference/gtk/gtk4.types.in b/docs/reference/gtk/gtk4.types.in
index 416ab5bc97..d93f495c80 100644
--- a/docs/reference/gtk/gtk4.types.in
+++ b/docs/reference/gtk/gtk4.types.in
@@ -54,6 +54,7 @@ gtk_constraint_layout_get_type
 gtk_constraint_target_get_type
 gtk_css_provider_get_type
 gtk_dialog_get_type
+gtk_directory_list_get_type
 gtk_drag_icon_get_type
 gtk_drag_source_get_type
 gtk_drawing_area_get_type
diff --git a/gtk/gtk.h b/gtk/gtk.h
index eba47fb967..3a6312d35d 100644
--- a/gtk/gtk.h
+++ b/gtk/gtk.h
@@ -86,6 +86,7 @@
 #include <gtk/gtkcustomlayout.h>
 #include <gtk/gtkdebug.h>
 #include <gtk/gtkdialog.h>
+#include <gtk/gtkdirectorylist.h>
 #include <gtk/gtkdragicon.h>
 #include <gtk/gtkdragsource.h>
 #include <gtk/gtkdrawingarea.h>
diff --git a/gtk/gtkdirectorylist.c b/gtk/gtkdirectorylist.c
new file mode 100644
index 0000000000..053305b674
--- /dev/null
+++ b/gtk/gtkdirectorylist.c
@@ -0,0 +1,681 @@
+/*
+ * Copyright © 2019 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 "gtkdirectorylist.h"
+
+#include "gtkintl.h"
+#include "gtkprivate.h"
+
+/**
+ * SECTION:gtkdirectorylist
+ * @title: GtkDirectoryList
+ * @short_description: A list model for directory listings
+ * @see_also: #GListModel, g_file_enumerate_children()
+ *
+ * #GtkDirectoryList is a list model that wraps g_file_enumerate_children_async().
+ * It presents a #GListModel and fills it asynchronously with the #GFileInfos
+ * returned from that function.
+ *
+ * Enumeration will start automatically when a the GtkDirectoryList:file property
+ * is set.
+ *
+ * While the #GtkDirectoryList is being filled, the GtkDirectoryList:loading
+ * property will be set to %TRUE. You can listen to that property if you want
+ * to show information like a #GtkSpinner or a "Loading..." text.
+ * If loading fails at any point, the GtkDirectoryList:error property will be set
+ * to give more indication about the failure.
+ *
+ * The #GFileInfos returned from a #GtkDirectoryList have the "standard::file"
+ * attribute set to the #GFile they refer to. This way you can get at the file
+ * that is referred to in the same way you would via g_file_enumerator_get_child().
+ * This means you do not need access to the #GtkDirectoryList but can access
+ * the #GFile directly from the #GFileInfo when operating with a #GtkListView or
+ * similar.
+ */
+
+/* random number that everyone else seems to use, too */
+#define FILES_PER_QUERY 100
+
+enum {
+  PROP_0,
+  PROP_ATTRIBUTES,
+  PROP_ERROR,
+  PROP_FILE,
+  PROP_IO_PRIORITY,
+  PROP_ITEM_TYPE,
+  PROP_LOADING,
+  NUM_PROPERTIES
+};
+
+struct _GtkDirectoryList
+{
+  GObject parent_instance;
+
+  char *attributes;
+  int io_priority;
+  GFile *file;
+
+  GCancellable *cancellable;
+  GError *error; /* Error while loading */
+  GSequence *items; /* Use GPtrArray or GListStore here? */
+};
+
+struct _GtkDirectoryListClass
+{
+  GObjectClass parent_class;
+};
+
+static GParamSpec *properties[NUM_PROPERTIES] = { NULL, };
+
+static GType
+gtk_directory_list_get_item_type (GListModel *list)
+{
+  return G_TYPE_FILE_INFO;
+}
+
+static guint
+gtk_directory_list_get_n_items (GListModel *list)
+{
+  GtkDirectoryList *self = GTK_DIRECTORY_LIST (list);
+
+  return g_sequence_get_length (self->items);
+}
+
+static gpointer
+gtk_directory_list_get_item (GListModel *list,
+                             guint       position)
+{
+  GtkDirectoryList *self = GTK_DIRECTORY_LIST (list);
+  GSequenceIter *iter;
+
+  iter = g_sequence_get_iter_at_pos (self->items, position);
+
+  if (g_sequence_iter_is_end (iter))
+    return NULL;
+  else
+    return g_object_ref (g_sequence_get (iter));
+}
+
+static void
+gtk_directory_list_model_init (GListModelInterface *iface)
+{
+  iface->get_item_type = gtk_directory_list_get_item_type;
+  iface->get_n_items = gtk_directory_list_get_n_items;
+  iface->get_item = gtk_directory_list_get_item;
+}
+
+G_DEFINE_TYPE_WITH_CODE (GtkDirectoryList, gtk_directory_list, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, gtk_directory_list_model_init))
+
+static void
+gtk_directory_list_set_property (GObject      *object,
+                                 guint         prop_id,
+                                 const GValue *value,
+                                 GParamSpec   *pspec)
+{
+  GtkDirectoryList *self = GTK_DIRECTORY_LIST (object);
+
+  switch (prop_id)
+    {
+    case PROP_ATTRIBUTES:
+      gtk_directory_list_set_attributes (self, g_value_get_string (value));
+      break;
+
+    case PROP_FILE:
+      gtk_directory_list_set_file (self, g_value_get_object (value));
+      break;
+
+    case PROP_IO_PRIORITY:
+      gtk_directory_list_set_io_priority (self, g_value_get_int (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void 
+gtk_directory_list_get_property (GObject     *object,
+                                 guint        prop_id,
+                                 GValue      *value,
+                                 GParamSpec  *pspec)
+{
+  GtkDirectoryList *self = GTK_DIRECTORY_LIST (object);
+
+  switch (prop_id)
+    {
+    case PROP_ATTRIBUTES:
+      g_value_set_string (value, self->attributes);
+      break;
+
+    case PROP_ERROR:
+      g_value_set_boxed (value, self->error);
+      break;
+
+    case PROP_FILE:
+      g_value_set_object (value, self->file);
+      break;
+
+    case PROP_IO_PRIORITY:
+      g_value_set_int (value, self->io_priority);
+      break;
+
+    case PROP_ITEM_TYPE:
+      g_value_set_gtype (value, G_TYPE_FILE_INFO);
+      break;
+
+    case PROP_LOADING:
+      g_value_set_boolean (value, gtk_directory_list_is_loading (self));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static gboolean
+gtk_directory_list_stop_loading (GtkDirectoryList *self)
+{
+  if (self->cancellable == NULL)
+    return FALSE;
+
+  g_cancellable_cancel (self->cancellable);
+  g_clear_object (&self->cancellable);
+  return TRUE;
+}
+
+static void
+gtk_directory_list_dispose (GObject *object)
+{
+  GtkDirectoryList *self = GTK_DIRECTORY_LIST (object);
+
+  gtk_directory_list_stop_loading (self);
+
+  g_clear_object (&self->file);
+  g_clear_pointer (&self->attributes, g_free);
+
+  g_clear_error (&self->error);
+  g_clear_pointer (&self->items, g_sequence_free);
+
+  G_OBJECT_CLASS (gtk_directory_list_parent_class)->dispose (object);
+}
+
+static void
+gtk_directory_list_class_init (GtkDirectoryListClass *class)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (class);
+
+  gobject_class->set_property = gtk_directory_list_set_property;
+  gobject_class->get_property = gtk_directory_list_get_property;
+  gobject_class->dispose = gtk_directory_list_dispose;
+
+  /**
+   * GtkDirectoryList:attributes:
+   *
+   * The attributes to query
+   */
+  properties[PROP_ATTRIBUTES] =
+      g_param_spec_string ("attributes",
+                           P_("attributes"),
+                           P_("Attributes to query"),
+                           NULL,
+                           GTK_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkDirectoryList:error:
+   *
+   * Error encountered while loading files
+   */
+  properties[PROP_ERROR] =
+      g_param_spec_boxed ("error",
+                          P_("error"),
+                          P_("Error encountered while loading files"),
+                          G_TYPE_ERROR,
+                          GTK_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkDirectoryList:file:
+   *
+   * File to query
+   */
+  properties[PROP_FILE] =
+      g_param_spec_object ("file",
+                           P_("File"),
+                           P_("The file to query"),
+                           G_TYPE_FILE,
+                           GTK_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkDirectoryList:io-priority:
+   *
+   * Priority used when loading
+   */
+  properties[PROP_IO_PRIORITY] =
+      g_param_spec_int ("io-priority",
+                        P_("IO priority"),
+                        P_("Priority used when loading"),
+                        -G_MAXINT, G_MAXINT, G_PRIORITY_DEFAULT,
+                        GTK_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkDirectoryList:item-type:
+   *
+   * The #GType for elements of this object
+   */
+  properties[PROP_ITEM_TYPE] =
+      g_param_spec_gtype ("item-type",
+                          P_("Item type"),
+                          P_("The type of elements of this object"),
+                          G_TYPE_FILE_INFO,
+                          GTK_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY);
+
+  /**
+   * GtkDirectoryList:loading:
+   *
+   * %TRUE if files are being loaded
+   */
+  properties[PROP_LOADING] =
+      g_param_spec_boolean ("loading",
+                            P_("loading"),
+                            P_("TRUE if files are being loaded"),
+                            FALSE,
+                            GTK_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY);
+
+  g_object_class_install_properties (gobject_class, NUM_PROPERTIES, properties);
+}
+
+static void
+gtk_directory_list_init (GtkDirectoryList *self)
+{
+  self->items = g_sequence_new (g_object_unref);
+  self->io_priority = G_PRIORITY_DEFAULT;
+}
+
+/**
+ * gtk_directory_list_new:
+ * @file: (allow-none): The file to query
+ * @attributes: (allow-none): The attributes to query with
+ *
+ * Creates a new #GtkDirectoryList querying the given @file with the given
+ * @attributes.
+ *
+ * Returns: a new #GtkDirectoryList
+ **/
+GtkDirectoryList *
+gtk_directory_list_new (const char *attributes,
+                        GFile      *file)
+                        
+{
+  g_return_val_if_fail (file == NULL || G_IS_FILE (file), NULL);
+
+  return g_object_new (GTK_TYPE_DIRECTORY_LIST,
+                       "attributes", attributes,
+                       "file", file,
+                       NULL);
+}
+
+static void
+gtk_directory_list_clear_items (GtkDirectoryList *self)
+{
+  guint n_items;
+
+  n_items = g_sequence_get_length (self->items);
+  if (n_items > 0)
+    {
+      g_sequence_remove_range (g_sequence_get_begin_iter (self->items),
+                               g_sequence_get_end_iter (self->items));
+
+      g_list_model_items_changed (G_LIST_MODEL (self), 0, n_items, 0);
+    }
+
+  if (self->error)
+    {
+      g_clear_error (&self->error);
+      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ERROR]);
+    }
+}
+
+static void
+gtk_directory_list_enumerator_closed_cb (GObject      *source,
+                                         GAsyncResult *res,
+                                         gpointer      user_data)
+{
+  g_file_enumerator_close_finish (G_FILE_ENUMERATOR (source), res, NULL);
+}
+
+static void
+gtk_directory_list_got_files_cb (GObject      *source,
+                                 GAsyncResult *res,
+                                 gpointer      user_data)
+{
+  GtkDirectoryList *self = user_data; /* invalid if cancelled */
+  GFileEnumerator *enumerator = G_FILE_ENUMERATOR (source);
+  GError *error = NULL;
+  GList *l, *files;
+  guint n;
+
+  files = g_file_enumerator_next_files_finish (enumerator, res, &error);
+
+  if (files == NULL)
+    {
+      if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        {
+          g_clear_error (&error);
+          return;
+        }
+
+      g_file_enumerator_close_async (enumerator,
+                                     self->io_priority,
+                                     NULL,
+                                     gtk_directory_list_enumerator_closed_cb,
+                                     NULL);
+
+      g_object_freeze_notify (G_OBJECT (self));
+
+      g_clear_object (&self->cancellable);
+      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LOADING]);
+
+      if (error)
+        {
+          self->error = error;
+          g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ERROR]);
+        }
+
+      g_object_thaw_notify (G_OBJECT (self));
+      return;
+    }
+
+  n = 0;
+  for (l = files; l; l = l->next)
+    {
+      GFileInfo *info;
+      GFile *file;
+      
+      info = l->data;
+      file = g_file_enumerator_get_child (enumerator, info);
+      g_file_info_set_attribute_object (info, "standard::file", G_OBJECT (file));
+      g_object_unref (file);
+      g_sequence_append (self->items, info);
+      n++;
+    }
+  g_list_free (files);
+
+  g_file_enumerator_next_files_async (enumerator,
+                                      g_file_is_native (self->file) ? 50 * FILES_PER_QUERY : FILES_PER_QUERY,
+                                      self->io_priority,
+                                      self->cancellable,
+                                      gtk_directory_list_got_files_cb,
+                                      self);
+
+  if (n > 0)
+    g_list_model_items_changed (G_LIST_MODEL (self), g_sequence_get_length (self->items) - n, 0, n);
+}
+
+static void
+gtk_directory_list_got_enumerator_cb (GObject      *source,
+                                      GAsyncResult *res,
+                                      gpointer      user_data)
+{
+  GtkDirectoryList *self = user_data; /* invalid if cancelled */
+  GFile *file = G_FILE (source);
+  GFileEnumerator *enumerator;
+  GError *error = NULL;
+
+  enumerator = g_file_enumerate_children_finish (file, res, &error);
+  if (enumerator == NULL)
+    {
+      if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        {
+          g_clear_error (&error);
+          return;
+        }
+
+      g_object_freeze_notify (G_OBJECT (self));
+      self->error = error;
+      g_clear_object (&self->cancellable);
+      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LOADING]);
+      g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ERROR]);
+      g_object_thaw_notify (G_OBJECT (self));
+      return;
+    }
+
+  g_file_enumerator_next_files_async (enumerator,
+                                      g_file_is_native (file) ? 50 * FILES_PER_QUERY : FILES_PER_QUERY,
+                                      self->io_priority,
+                                      self->cancellable,
+                                      gtk_directory_list_got_files_cb,
+                                      self);
+  g_object_unref (enumerator);
+}
+
+static void
+gtk_directory_list_start_loading (GtkDirectoryList *self)
+{
+  gboolean was_loading;
+
+  was_loading = gtk_directory_list_stop_loading (self);
+  gtk_directory_list_clear_items (self);
+
+  if (self->file == NULL)
+    {
+      if (was_loading)
+        g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LOADING]);
+      return;
+    }
+
+  self->cancellable = g_cancellable_new ();
+  g_file_enumerate_children_async (self->file,
+                                   self->attributes,
+                                   G_FILE_QUERY_INFO_NONE,
+                                   self->io_priority,
+                                   self->cancellable,
+                                   gtk_directory_list_got_enumerator_cb,
+                                   self);
+
+  if (!was_loading)
+    g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LOADING]);
+}
+
+/**
+ * gtk_directory_list_set_file:
+ * @self: a #GtkDirectoryList
+ * @file: (allow-none): the #GFile to be enumerated
+ *
+ * Sets the @file to be enumerated and starts the enumeration.
+ *
+ * If @file is %NULL, the result will be an empty list.
+ */
+void
+gtk_directory_list_set_file (GtkDirectoryList *self,
+                             GFile            *file)
+{
+  g_return_if_fail (GTK_IS_DIRECTORY_LIST (self));
+  g_return_if_fail (file == NULL || G_IS_FILE (file));
+
+  if (self->file == file ||
+      (self->file && file && g_file_equal (self->file, file)))
+    return;
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  g_set_object (&self->file, file);
+
+  gtk_directory_list_start_loading (self);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_FILE]);
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+/**
+ * gtk_directory_list_get_file:
+ * @self: a #GtkDirectoryList
+ *
+ * Gets the file whose children are currently enumerated.
+ *
+ * Returns: (nullable) (transfer none): The file whose children are enumerated
+ **/
+GFile *
+gtk_directory_list_get_file (GtkDirectoryList *self)
+{
+  g_return_val_if_fail (GTK_IS_DIRECTORY_LIST (self), NULL);
+
+  return self->file;
+}
+
+/**
+ * gtk_directory_list_set_attributes:
+ * @self: a #GtkDirectoryList
+ * @attributes: (allow-none): the attributes to enumerate
+ *
+ * Sets the @attributes to be enumerated and starts the enumeration.
+ *
+ * If @attributes is %NULL, no attributes will be queried, but a list
+ * of #GFileInfos will still be created.
+ */
+void
+gtk_directory_list_set_attributes (GtkDirectoryList *self,
+                                   const char       *attributes)
+{
+  g_return_if_fail (GTK_IS_DIRECTORY_LIST (self));
+
+  if (self->attributes == attributes)
+    return;
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  g_free (self->attributes);
+  self->attributes = g_strdup (attributes);
+
+  gtk_directory_list_start_loading (self);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ATTRIBUTES]);
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+/**
+ * gtk_directory_list_get_attributes:
+ * @self: a #GtkDirectoryList
+ *
+ * Gets the attributes queried on the children.
+ *
+ * Returns: (nullable) (transfer none): The queried attributes
+ */
+const char *
+gtk_directory_list_get_attributes (GtkDirectoryList *self)
+{
+  g_return_val_if_fail (GTK_IS_DIRECTORY_LIST (self), NULL);
+
+  return self->attributes;
+}
+
+/**
+ * gtk_directory_list_set_io_priority:
+ * @self: a #GtkDirectoryList
+ * @io_priority: IO priority to use
+ *
+ * Sets the IO priority to use while loading directories.
+ *
+ * Setting the priority while @self is loading will reprioritize the
+ * ongoing load as soon as possible.
+ *
+ * The default IO priority is %G_PRIORITY_DEFAULT, which is higher than
+ * the GTK redraw priority. If you are loading a lot of directories in
+ * parrallel, lowering it to something like %G_PRIORITY_DEFAULT_IDLE
+ * may increase responsiveness.
+ */
+void
+gtk_directory_list_set_io_priority (GtkDirectoryList *self,
+                                    int               io_priority)
+{
+  g_return_if_fail (GTK_IS_DIRECTORY_LIST (self));
+
+  if (self->io_priority == io_priority)
+    return;
+
+  self->io_priority = io_priority;
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_IO_PRIORITY]);
+}
+
+/**
+ * gtk_directory_list_get_io_priority:
+ * @self: a #GtkDirectoryList
+ *
+ * Gets the IO priority set via gtk_directory_list_set_io_priority().
+ *
+ * Returns: The IO priority.
+ */
+int
+gtk_directory_list_get_io_priority (GtkDirectoryList *self)
+{
+  g_return_val_if_fail (GTK_IS_DIRECTORY_LIST (self), G_PRIORITY_DEFAULT);
+
+  return self->io_priority;
+}
+
+/**
+ * gtk_directory_list_is_loading:
+ * @self: a #GtkDirectoryList
+ *
+ * Returns %TRUE if the children enumeration is currently in
+ * progress.
+ * Files will be added to @self from time to time while loading is
+ * going on. The order in which are added is undefined and may change
+ * inbetween runs.
+ *
+ * Returns: %TRUE if @self is loading
+ */
+gboolean
+gtk_directory_list_is_loading (GtkDirectoryList *self)
+{
+  g_return_val_if_fail (GTK_IS_DIRECTORY_LIST (self), FALSE);
+
+  return self->cancellable != NULL;
+}
+
+/**
+ * gtk_directory_list_get_error:
+ * @self: a #GtkDirectoryList
+ *
+ * Gets the loading error, if any.
+ *
+ * If an error occurs during the loading process, the loading process
+ * will finish and this property allows querying the error that happened.
+ * This error will persist until a file is loaded again.
+ *
+ * An error being set does not mean that no files were loaded, and all
+ * successfully queried files will remain in the list.
+ *
+ * Returns: (nullable) (transfer none): The loading error or %NULL if
+ *     loading finished successfully.
+ */
+const GError *
+gtk_directory_list_get_error (GtkDirectoryList *self)
+{
+  g_return_val_if_fail (GTK_IS_DIRECTORY_LIST (self), FALSE);
+
+  return self->error;
+}
+
diff --git a/gtk/gtkdirectorylist.h b/gtk/gtkdirectorylist.h
new file mode 100644
index 0000000000..0952224c40
--- /dev/null
+++ b/gtk/gtkdirectorylist.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2019 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_DIRECTORY_LIST_H__
+#define __GTK_DIRECTORY_LIST_H__
+
+
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
+#include <gio/gio.h>
+/* for GDK_AVAILABLE_IN_ALL */
+#include <gdk/gdk.h>
+
+
+G_BEGIN_DECLS
+
+#define GTK_TYPE_DIRECTORY_LIST (gtk_directory_list_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_FINAL_TYPE (GtkDirectoryList, gtk_directory_list, GTK, DIRECTORY_LIST, GObject)
+
+GDK_AVAILABLE_IN_ALL
+GtkDirectoryList *      gtk_directory_list_new                  (const char             *attributes,
+                                                                 GFile                  *file);
+
+GDK_AVAILABLE_IN_ALL
+void                    gtk_directory_list_set_file             (GtkDirectoryList       *self,
+                                                                 GFile                  *file);
+GDK_AVAILABLE_IN_ALL
+GFile *                 gtk_directory_list_get_file             (GtkDirectoryList       *self);
+GDK_AVAILABLE_IN_ALL
+void                    gtk_directory_list_set_attributes       (GtkDirectoryList       *self,
+                                                                 const char             *attributes);
+GDK_AVAILABLE_IN_ALL
+const char *            gtk_directory_list_get_attributes       (GtkDirectoryList       *self);
+GDK_AVAILABLE_IN_ALL
+void                    gtk_directory_list_set_io_priority      (GtkDirectoryList       *self,
+                                                                 int                     io_priority);
+GDK_AVAILABLE_IN_ALL
+int                     gtk_directory_list_get_io_priority      (GtkDirectoryList       *self);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gtk_directory_list_is_loading           (GtkDirectoryList       *self);
+GDK_AVAILABLE_IN_ALL
+const GError *          gtk_directory_list_get_error            (GtkDirectoryList       *self);
+
+G_END_DECLS
+
+#endif /* __GTK_DIRECTORY_LIST_H__ */
diff --git a/gtk/meson.build b/gtk/meson.build
index 9012ae1a5c..260e3ebd1b 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -201,6 +201,7 @@ gtk_public_sources = files([
   'gtkcssprovider.c',
   'gtkcustomlayout.c',
   'gtkdialog.c',
+  'gtkdirectorylist.c',
   'gtkdragicon.c',
   'gtkdragsource.c',
   'gtkdrawingarea.c',
@@ -455,6 +456,7 @@ gtk_public_headers = files([
   'gtkcustomlayout.h',
   'gtkdebug.h',
   'gtkdialog.h',
+  'gtkdirectorylist.h',
   'gtkdragicon.h',
   'gtkdragsource.h',
   'gtkdrawingarea.h',