[gtk+] GtkSearchEntry: Delay the changed signal by default

[Bastien Nocera <hadess src gnome org>]

commit 51e238653d720c9adfb587476bf708c0df92461e
Author: Bastien Nocera <hadess hadess net>
Date:   Thu May 16 18:20:19 2013 +0200

    GtkSearchEntry: Delay the changed signal by default
    
    Emit the "changed" signal after 150 msecs, so that searching
    through big lists, or doing online searches feels more responsive.
    
    This is something already done in various applications to make
    search-as-you type more responsive (gnome-shell, gnome-documents,
    gnome-control-center, etc.). The 150 msecs is the value currently
    used by gnome-shell, so keep it (invisibly) consistent.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=700229

 demos/gtk-demo/Makefile.am        |    1 +
 demos/gtk-demo/demo.gresource.xml |    1 +
 demos/gtk-demo/search_entry2.c    |   96 +++++++++++++++++++++++++++++++++++++
 gtk/gtksearchentry.c              |   73 ++++++++++++++++++++++++++--
 4 files changed, 166 insertions(+), 5 deletions(-)
---
diff --git a/demos/gtk-demo/Makefile.am b/demos/gtk-demo/Makefile.am
index a576483..8e8da27 100644
--- a/demos/gtk-demo/Makefile.am
+++ b/demos/gtk-demo/Makefile.am
@@ -42,6 +42,7 @@ demos =                                               \
        revealer.c                              \
        rotated_text.c                          \
        search_entry.c                          \
+       search_entry2.c                         \
        sizegroup.c                             \
        spinner.c                               \
        stack.c                                 \
diff --git a/demos/gtk-demo/demo.gresource.xml b/demos/gtk-demo/demo.gresource.xml
index 28c01aa..b95fcf9 100644
--- a/demos/gtk-demo/demo.gresource.xml
+++ b/demos/gtk-demo/demo.gresource.xml
@@ -116,6 +116,7 @@
     <file>revealer.c</file>
     <file>rotated_text.c</file>
     <file>search_entry.c</file>
+    <file>search_entry2.c</file>
     <file>sizegroup.c</file>
     <file>stack.c</file>
     <file>spinner.c</file>
diff --git a/demos/gtk-demo/search_entry2.c b/demos/gtk-demo/search_entry2.c
new file mode 100644
index 0000000..cdadc78
--- /dev/null
+++ b/demos/gtk-demo/search_entry2.c
@@ -0,0 +1,96 @@
+/* Entry/Delayed Search Entry
+ *
+ * GtkSearchEntry sets up GtkEntries ready for search. Search entries
+ * have their "changed" signal delayed and should be used
+ * when the searched operation is slow such as loads of entries
+ * to search, or online searches.
+ */
+
+#include <gtk/gtk.h>
+
+static GtkWidget *window = NULL;
+
+static void
+search_entry_destroyed (GtkWidget  *widget)
+{
+  window = NULL;
+}
+
+static void
+search_changed_cb (GtkSearchEntry *entry,
+                   GtkLabel       *result_label)
+{
+  const char *text;
+  text = gtk_entry_get_text (GTK_ENTRY (entry));
+  g_message ("search changed: %s", text);
+  gtk_label_set_text (result_label, text ? text : "");
+}
+
+GtkWidget *
+do_search_entry2 (GtkWidget *do_widget)
+{
+  GtkWidget *content_area;
+  GtkWidget *vbox;
+  GtkWidget *hbox;
+  GtkWidget *label;
+  GtkWidget *entry;
+  GtkWidget *button;
+
+  if (!window)
+    {
+      window = gtk_dialog_new_with_buttons ("Search Entry #2",
+                                            GTK_WINDOW (do_widget),
+                                            0,
+                                            GTK_STOCK_CLOSE,
+                                            GTK_RESPONSE_NONE,
+                                            NULL);
+      gtk_window_set_resizable (GTK_WINDOW (window), FALSE);
+
+      g_signal_connect (window, "response",
+                        G_CALLBACK (gtk_widget_destroy), NULL);
+      g_signal_connect (window, "destroy",
+                        G_CALLBACK (search_entry_destroyed), &window);
+
+      content_area = gtk_dialog_get_content_area (GTK_DIALOG (window));
+
+      vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 5);
+      gtk_box_pack_start (GTK_BOX (content_area), vbox, TRUE, TRUE, 0);
+      gtk_container_set_border_width (GTK_CONTAINER (vbox), 5);
+
+      label = gtk_label_new (NULL);
+      gtk_label_set_markup (GTK_LABEL (label), "Search entry demo #2");
+      gtk_box_pack_start (GTK_BOX (vbox), label, FALSE, FALSE, 0);
+
+      /* Create our entry */
+      entry = gtk_search_entry_new ();
+      gtk_box_pack_start (GTK_BOX (vbox), entry, FALSE, FALSE, 0);
+
+      /* Result */
+      hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 10);
+      gtk_box_pack_start (GTK_BOX (vbox), hbox, TRUE, TRUE, 0);
+      gtk_container_set_border_width (GTK_CONTAINER (hbox), 0);
+
+      label = gtk_label_new ("Result:");
+      gtk_box_pack_start (GTK_BOX (hbox), label, TRUE, TRUE, 0);
+
+      label = gtk_label_new ("");
+      gtk_box_pack_start (GTK_BOX (hbox), label, TRUE, TRUE, 0);
+
+      g_signal_connect (entry, "changed",
+                        G_CALLBACK (search_changed_cb), label);
+
+      /* Give the focus to the close button */
+      button = gtk_dialog_get_widget_for_response (GTK_DIALOG (window), GTK_RESPONSE_NONE);
+      gtk_widget_grab_focus (button);
+    }
+
+  if (!gtk_widget_get_visible (window))
+    gtk_widget_show_all (window);
+  else
+    {
+      gtk_widget_destroy (window);
+      window = NULL;
+    }
+
+  return window;
+}
diff --git a/gtk/gtksearchentry.c b/gtk/gtksearchentry.c
index b28406a..b79705b 100644
--- a/gtk/gtksearchentry.c
+++ b/gtk/gtksearchentry.c
@@ -51,9 +51,37 @@
 
 G_DEFINE_TYPE (GtkSearchEntry, gtk_search_entry, GTK_TYPE_ENTRY)
 
+typedef struct {
+  guint delayed_changed_id;
+  gboolean in_timeout;
+} GtkSearchEntryPrivate;
+
+/* 150 mseconds of delay */
+#define DELAYED_TIMEOUT_ID 150
+
+/* This widget got created without a private structure, meaning
+ * that we cannot now have one without breaking ABI */
+#define GET_PRIV(e) G_TYPE_INSTANCE_GET_PRIVATE (e, GTK_TYPE_SEARCH_ENTRY, GtkSearchEntryPrivate)
+
+static void
+gtk_search_entry_finalize (GObject *object)
+{
+  GtkSearchEntryPrivate *priv = GET_PRIV (object);
+
+  if (priv->delayed_changed_id > 0)
+    g_source_remove (priv->delayed_changed_id);
+
+  G_OBJECT_CLASS (gtk_search_entry_parent_class)->finalize (object);
+}
+
 static void
 gtk_search_entry_class_init (GtkSearchEntryClass *klass)
 {
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = gtk_search_entry_finalize;
+
+  g_type_class_add_private (klass, sizeof (GtkSearchEntryPrivate));
 }
 
 static void
@@ -63,14 +91,42 @@ search_entry_clear_cb (GtkEntry *entry,
   gtk_entry_set_text (entry, "");
 }
 
+static gboolean
+gtk_search_entry_changed_timeout_cb (gpointer user_data)
+{
+  GtkSearchEntry *entry = user_data;
+  GtkSearchEntryPrivate *priv = GET_PRIV (entry);
+
+  priv->in_timeout = TRUE;
+  g_signal_emit_by_name (entry, "changed");
+  priv->delayed_changed_id = 0;
+  priv->in_timeout = FALSE;
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+reset_timeout (GtkSearchEntry *entry)
+{
+  GtkSearchEntryPrivate *priv = GET_PRIV (entry);
+
+  if (priv->delayed_changed_id > 0)
+    g_source_remove (priv->delayed_changed_id);
+  priv->delayed_changed_id = g_timeout_add (DELAYED_TIMEOUT_ID,
+                                            gtk_search_entry_changed_timeout_cb,
+                                            entry);
+}
+
 static void
-search_entry_changed_cb (GtkEntry *entry,
-                         gpointer  user_data)
+search_entry_changed_cb (GtkSearchEntry *entry,
+                         gpointer        user_data)
 {
+  GtkSearchEntryPrivate *priv = GET_PRIV (entry);
   const char *str, *icon_name;
   gboolean active;
 
-  str = gtk_entry_get_text (entry);
+  /* Update the icons first */
+  str = gtk_entry_get_text (GTK_ENTRY (entry));
 
   if (str == NULL || *str == '\0')
     {
@@ -91,6 +147,15 @@ search_entry_changed_cb (GtkEntry *entry,
                 "secondary-icon-activatable", active,
                 "secondary-icon-sensitive", active,
                 NULL);
+
+  /* Don't stop the emission if it's the timeout
+   * emitting the signal, otherwise we'll get in a loop */
+  if (priv->in_timeout)
+    return;
+
+  /* Queue up the timeout */
+  reset_timeout (entry);
+  g_signal_stop_emission_by_name (entry, "changed");
 }
 
 static void
@@ -106,8 +171,6 @@ gtk_search_entry_init (GtkSearchEntry *entry)
                 "primary-icon-activatable", FALSE,
                 "primary-icon-sensitive", FALSE,
                 NULL);
-
-  search_entry_changed_cb (GTK_ENTRY (entry), NULL);
 }
 
 /**