GtkAboutDialog: Make credits section extensible

This commit adds API that allows to add new named sections
to the Credits part of GtkAboutDialog, in addition to the
hardcoded sections for authors, documenters, artists and
translators.

https://bugzilla.gnome.org/show_bug.cgi?id=484693

docs/reference/gtk/gtk3-sections.txt

@@ -37,6 +37,7 @@ gtk_about_dialog_get_logo
 gtk_about_dialog_set_logo
 gtk_about_dialog_get_logo_icon_name
 gtk_about_dialog_set_logo_icon_name
+gtk_about_dialog_add_credit_section
 gtk_show_about_dialog
 <SUBSECTION Standard>
 GTK_ABOUT_DIALOG

gtk/gtk.symbols

@@ -1,6 +1,7 @@
 /* This list defines the GTK+ ABI. It is used to generate the gtk.def
  * file.
  */
+gtk_about_dialog_add_credit_section
 gtk_about_dialog_get_artists
 gtk_about_dialog_get_authors
 gtk_about_dialog_get_comments

gtk/gtkaboutdialog.c

@@ -122,6 +122,12 @@ static const gchar *gtk_license_urls[] = {
   "http://opensource.org/licenses/artistic-license-2.0.php"
 };
 
+typedef struct
+{
+  gchar *heading;
+  gchar **people;
+} CreditSection;
+
 struct _GtkAboutDialogPrivate 
 {
   gchar *name;
@@ -137,6 +143,9 @@ struct _GtkAboutDialogPrivate
   gchar **documenters;
   gchar **artists;
 
+
+  GSList *credit_sections;
+
   gint credits_page;
   gint license_page;
 
@@ -163,6 +172,8 @@ struct _GtkAboutDialogPrivate
   guint wrap_license : 1;
 };
 
+
+
 #define GTK_ABOUT_DIALOG_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GTK_TYPE_ABOUT_DIALOG, GtkAboutDialogPrivate))
 
 
@@ -561,6 +572,7 @@ update_credits_button_visibility (GtkAboutDialog *about)
   show = (priv->authors != NULL ||
           priv->documenters != NULL ||
           priv->artists != NULL ||
+          priv->credit_sections != NULL ||
          (priv->translator_credits != NULL &&
           strcmp (priv->translator_credits, "translator_credits") &&
           strcmp (priv->translator_credits, "translator-credits")));
@@ -775,6 +787,15 @@ gtk_about_dialog_init (GtkAboutDialog *about)
   gtk_about_dialog_set_logo (about, NULL);
 }
 
+
+void destroy_credit_section (gpointer data)
+{
+  CreditSection *cs = data;
+  g_free (cs->heading);
+  g_strfreev (cs->people);
+  g_slice_free (CreditSection, data);
+}
+
 static void
 gtk_about_dialog_finalize (GObject *object)
 {
@@ -794,6 +815,8 @@ gtk_about_dialog_finalize (GObject *object)
   g_strfreev (priv->documenters);
   g_strfreev (priv->artists);
 
+  g_slist_free_full (priv->credit_sections, destroy_credit_section);
+
   g_slist_foreach (priv->visited_links, (GFunc)g_free, NULL);
   g_slist_free (priv->visited_links);
 
@@ -2393,6 +2416,16 @@ create_credits_page (GtkAboutDialog *about)
   if (priv->artists != NULL)
     add_credits_section (about, GTK_GRID (grid), &row, _("Artwork by"), priv->artists);
 
+  if (priv->credit_sections != NULL)
+    {
+      GSList *cs;
+      for (cs = priv->credit_sections; cs != NULL; cs = cs->next)
+	{
+	  CreditSection *section = cs->data;
+	  add_credits_section (about, GTK_GRID (grid), &row, section->heading, section->people);
+	}
+    }
+
   gtk_widget_show_all (sw);
 }
 
@@ -2627,3 +2660,35 @@ gtk_about_dialog_get_license_type (GtkAboutDialog *about)
 
   return about->priv->license_type;
 }
+
+/**
+ * gtk_about_dialog_add_credit_section:
+ * @about: A #GtkAboutDialog
+ * @section_name: The name of the section
+ * @people: The people who belong to that section
+ *
+ * Creates a new section in the Credits page.
+ *
+ * Since: 3.4
+ */
+void
+gtk_about_dialog_add_credit_section (GtkAboutDialog  *about,
+                                     const gchar     *section_name,
+                                     const gchar    **people)
+{
+  GtkAboutDialogPrivate *priv;
+  CreditSection *new_entry;
+
+  g_return_if_fail (GTK_IS_ABOUT_DIALOG (about));
+  g_return_if_fail (section_name != NULL);
+  g_return_if_fail (people != NULL);
+
+  priv = about->priv;
+
+  new_entry = g_slice_new (CreditSection);
+  new_entry->heading = g_strdup ((gchar *)section_name);
+  new_entry->people = g_strdupv ((gchar **)people);
+
+  priv->credit_sections = g_slist_append (priv->credit_sections, new_entry);
+  update_credits_button_visibility (about);
+}

gtk/gtkaboutdialog.h

@@ -159,6 +159,9 @@ void                   gtk_about_dialog_set_logo               (GtkAboutDialog
 const gchar *          gtk_about_dialog_get_logo_icon_name     (GtkAboutDialog  *about);
 void                   gtk_about_dialog_set_logo_icon_name     (GtkAboutDialog  *about,
                                                                 const gchar     *icon_name);
+void                  gtk_about_dialog_add_credit_section      (GtkAboutDialog  *about,
+                                                                const gchar     *section_name,
+                                                                const gchar    **people);
 
 G_END_DECLS