Symbol Pane - indicate when loading

src/SymbolPane/C/CtagsSymbolOutline.vala

@@ -55,6 +55,7 @@ public class Scratch.Services.CtagsSymbolOutline : Scratch.Services.SymbolOutlin
     }
 
     public override void parse_symbols () {
+        before_parse ();
         if (current_subprocess != null)
             current_subprocess.force_exit ();
 
@@ -64,9 +65,12 @@ public class Scratch.Services.CtagsSymbolOutline : Scratch.Services.SymbolOutlin
                 "ctags", "-f", "-", "--format=2", "--excmd=n", "--fields=nstK", "--extra=", "--sort=no", doc.file.get_path ()
             );
 
-            parse_output.begin (current_subprocess);
+            parse_output.begin (current_subprocess, (obj, res) => {
+                after_parse ();
+            });
         } catch (GLib.Error e) {
             critical (e.message);
+            after_parse ();
         }
     }
 

src/SymbolPane/SymbolOutline.vala

@@ -69,6 +69,7 @@ public class Scratch.Services.SymbolOutline : Gtk.Box {
     const string ACTION_PREFIX = ACTION_GROUP + ".";
     const string ACTION_SELECT = "action-select";
     const string ACTION_TOGGLE = "toggle-";
+    const uint SPINNER_DELAY_MSEC = 300;
     SimpleActionGroup symbol_action_group;
 
     public Scratch.Services.Document doc { get; construct; }
@@ -86,10 +87,36 @@ public class Scratch.Services.SymbolOutline : Gtk.Box {
         }
     }
 
+    protected bool took_too_long;
+    private uint show_spinner_timeout_id = 0;
+    protected void before_parse () {
+        tool_box_sensitive = true;
+        took_too_long = false;
+        show_spinner_timeout_id = Timeout.add (SPINNER_DELAY_MSEC, () => {
+            show_spinner_timeout_id = 0;
+            stack.visible_child = spinner;
+            spinner.start ();
+            return Source.REMOVE;
+        });
+    }
+
+    protected void after_parse () {
+        if (show_spinner_timeout_id > 0) {
+            Source.remove (show_spinner_timeout_id);
+            show_spinner_timeout_id = 0;
+        }
+
+        spinner.stop ();
+        stack.visible_child = filter_button;
+        tool_box_sensitive = !took_too_long;
+    }
+
     public virtual void parse_symbols () {}
     public virtual void add_tooltips (Code.Widgets.SourceList.ExpandableItem root) {}
 
-    Gtk.MenuButton filter_button;
+    private Gtk.MenuButton filter_button;
+    private Gtk.Spinner spinner;
+    private Gtk.Stack stack;
 
     construct {
         symbol_action_group = new SimpleActionGroup ();
@@ -145,9 +172,15 @@ public class Scratch.Services.SymbolOutline : Gtk.Box {
 
         filter_button.menu_model = top_model;
 
+        spinner = new Gtk.Spinner ();
+        stack = new Gtk.Stack ();
+        stack.add (filter_button);
+        stack.add (spinner);
+        stack.visible_child = filter_button;
+
         var tool_box = new Gtk.Box (HORIZONTAL, 3);
         tool_box.add (search_entry);
-        tool_box.add (filter_button);
+        tool_box.add (stack);
         add (tool_box);
         add (store);
         set_up_css ();

src/SymbolPane/Vala/ValaSymbolOutline.vala

@@ -74,7 +74,7 @@ public class Scratch.Services.ValaSymbolOutline : Scratch.Services.SymbolOutline
 
     private uint parse_timeout_id = 0;
     public override void parse_symbols () {
-        tool_box_sensitive = true;
+        before_parse ();
         var context = new Vala.CodeContext ();
 #if VALA_0_50
         context.set_target_profile (Vala.Profile.GOBJECT, false);
@@ -95,7 +95,6 @@ public class Scratch.Services.ValaSymbolOutline : Scratch.Services.SymbolOutline
             resolver.resolve (context);
             Vala.CodeContext.pop ();
 
-            bool took_too_long = false;
             parse_timeout_id = Timeout.add_full (Priority.LOW, PARSE_TIME_MAX_MSEC, () => {
                 parse_timeout_id = 0;
                 took_too_long = true;
@@ -126,21 +125,20 @@ public class Scratch.Services.ValaSymbolOutline : Scratch.Services.SymbolOutline
                         };
 
                         store.root.add (warning_item);
-                        tool_box_sensitive = false;
-
                     } else {
                         store.root.add (new_root);
                     }
 
                     store.root.expand_all ();
                     add_tooltips (store.root);
                     store.vadjustment.set_value (adjustment_value);
-                    return false;
+                    return Source.REMOVE;
                 });
             } else {
                 destroy_all_children (new_root);
             }
 
+            after_parse ();
             return null;
         });
     }