GTK: fixed bogus "(Unnamed)" strings in the message line

* An empty message line would actually contain "(Unnamed)".
* Info popups must discern the "(Unnamed)" string (e.g. a file with that name)
  from the actual unnamed buffer since when clicking the unnamed buffer, you
  must insert nothing (`EB$`). Therefore, the unnamed buffer is represented
  as an empty string. "(Unnamed)" is just a placeholder for rendering.
  This was carried over into TecoGtkLabel which always rendered the empty string
  as "(Unnamed)".
  But TecoGtkLabels are used for the info and message lines as well.
* Therefore the fallback/placeholder string is now configurable per label.
* On the downside, this wastes one more machine word per TecoGtkLabel.
  The alternative would have been to use {NULL, 0} as the representation
  for unnamed buffers, so you can actually discern the empty string from the
  unnamed buffer representation.
  However it feels wrong to have this kind of info-popup-specific handling
  in a more generic label widget.
  Also, for consistency we'd have to touch the Curses UI as well where
  the unnamed buffer is also currently internally represented by empty
  strings (as opposed to NULL).
* Regression introduced by 0c89fb700957e411885e7e7835e15f441e8b5e84,
  so it was in v2.5.0.

4 files changed, 22 insertions, 10 deletions

diff --git a/src/interface-gtk/gtk-info-popup.c b/src/interface-gtk/gtk-info-popup.c
index 769f772..f2c8dc8 100644
--- a/src/interface-gtk/gtk-info-popup.c
+++ b/src/interface-gtk/gtk-info-popup.c
@@ -30,6 +30,8 @@
 #include "gtk-label.h"
 #include "gtk-info-popup.h"
 
+#define TECO_UNNAMED_FILE "(Unnamed)"
+
 /*
  * FIXME: This is redundant with curses-info-popup.c.
  */
@@ -336,7 +338,7 @@ teco_gtk_info_popup_idle_add(TecoGtkInfoPopup *self, teco_popup_entry_type_t typ
 		}
 	}
 
-	GtkWidget *label = teco_gtk_label_new(name, len);
+	GtkWidget *label = teco_gtk_label_new(name, len, TECO_UNNAMED_FILE);
 	/*
 	 * Gtk v3.20 changed the CSS element names.
 	 * Adding a style class eases writing a portable fallback.css.
diff --git a/src/interface-gtk/gtk-label.c b/src/interface-gtk/gtk-label.c
index 5052cdc..6e05045 100644
--- a/src/interface-gtk/gtk-label.c
+++ b/src/interface-gtk/gtk-label.c
@@ -32,8 +32,6 @@
 
 #include "gtk-label.h"
 
-#define TECO_UNNAMED_FILE	"(Unnamed)"
-
 #define GDK_TO_PANGO_COLOR(X)	((guint16)((X) * G_MAXUINT16))
 
 struct _TecoGtkLabel {
@@ -42,8 +40,10 @@ struct _TecoGtkLabel {
 	PangoColor fg, bg;
 	guint16 fg_alpha, bg_alpha;
 
-	/** text backing the label or empty string for "(Unnamed)" buffer */
+	/** text backing the label or empty string for fallback */
 	teco_string_t string;
+	/** fallback string to render if `string` is empty or NULL */
+	const gchar *fallback;
 };
 
 G_DEFINE_TYPE(TecoGtkLabel, teco_gtk_label, GTK_TYPE_LABEL)
@@ -125,11 +125,21 @@ teco_gtk_label_class_init(TecoGtkLabelClass *klass)
 
 static void teco_gtk_label_init(TecoGtkLabel *self) {}
 
+/**
+ * Create new TECO label widget.
+ *
+ * @param str String to render (can be NULL)
+ * @param len Length of str or negative value for null-terminated strings.
+ * @param fallback Null-terminated fallback string to render
+ *   instead of empty strings.
+ *   Must be a string constant with global lifetime or NULL.
+ */
 GtkWidget *
-teco_gtk_label_new(const gchar *str, gssize len)
+teco_gtk_label_new(const gchar *str, gssize len, const gchar *fallback)
 {
 	TecoGtkLabel *widget = TECO_GTK_LABEL(g_object_new(TECO_TYPE_GTK_LABEL, NULL));
 
+	widget->fallback = fallback;
 	teco_gtk_label_set_text(widget, str, len);
 
 	return GTK_WIDGET(widget);
@@ -255,8 +265,8 @@ teco_gtk_label_set_text(TecoGtkLabel *self, const gchar *str, gssize len)
 	teco_string_init(&self->string, str, len < 0 ? strlen(str) : len);
 
 	teco_string_t string = self->string;
-	if (!string.len) {
-		string.data = TECO_UNNAMED_FILE;
+	if (!string.len && self->fallback) {
+		string.data = (gchar *)self->fallback;
 		string.len = strlen(string.data);
 	}
 
diff --git a/src/interface-gtk/gtk-label.h b/src/interface-gtk/gtk-label.h
index ad39c6e..a84608a 100644
--- a/src/interface-gtk/gtk-label.h
+++ b/src/interface-gtk/gtk-label.h
@@ -24,7 +24,7 @@
 #define TECO_TYPE_GTK_LABEL teco_gtk_label_get_type()
 G_DECLARE_FINAL_TYPE(TecoGtkLabel, teco_gtk_label, TECO, GTK_LABEL, GtkLabel)
 
-GtkWidget *teco_gtk_label_new(const gchar *str, gssize len);
+GtkWidget *teco_gtk_label_new(const gchar *str, gssize len, const gchar *fallback);
 
 void teco_gtk_label_set_text(TecoGtkLabel *self, const gchar *str, gssize len);
 teco_string_t teco_gtk_label_get_text(TecoGtkLabel *self);
diff --git a/src/interface-gtk/interface.c b/src/interface-gtk/interface.c
index 0e1507f..ace3a2f 100644
--- a/src/interface-gtk/interface.c
+++ b/src/interface-gtk/interface.c
@@ -202,7 +202,7 @@ teco_interface_init(void)
 	 */
 	teco_interface.info_bar_widget = gtk_header_bar_new();
 	gtk_widget_set_name(teco_interface.info_bar_widget, "sciteco-info-bar");
-	teco_interface.info_name_widget = teco_gtk_label_new("", 0);
+	teco_interface.info_name_widget = teco_gtk_label_new(NULL, 0, NULL);
 	gtk_widget_set_valign(teco_interface.info_name_widget, GTK_ALIGN_CENTER);
 	/* eases writing portable fallback.css that avoids CSS element names */
 	gtk_style_context_add_class(gtk_widget_get_style_context(teco_interface.info_name_widget),
@@ -288,7 +288,7 @@ teco_interface_init(void)
 	gtk_widget_set_name(teco_interface.message_bar_widget, "sciteco-message-bar");
 	GtkWidget *message_bar_content =
 			gtk_info_bar_get_content_area(GTK_INFO_BAR(teco_interface.message_bar_widget));
-	teco_interface.message_widget = teco_gtk_label_new(NULL, 0);
+	teco_interface.message_widget = teco_gtk_label_new(NULL, 0, NULL);
 	/* eases writing portable fallback.css that avoids CSS element names */
 	gtk_style_context_add_class(gtk_widget_get_style_context(teco_interface.message_widget),
 	                            "label");