[latexila] MainWindow: rework sensitivity updates

[Sébastien Wilmet <swilmet src gnome org>]

commit 9fbba1b3820465a348a19f46234a5f1092a2f602
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon Aug 14 19:59:22 2017 +0200

    MainWindow: rework sensitivity updates
    
    This fixes a recent regression introduced by
    commit bcff602c95208b167249cfd596d038583dbf7a1b:
    
    For the build tools actions: empty notebook -> open a file -> the build
    tools actions were still insensitive. This is now fixed. The
    MainWindowBuildTools's update_sensitivity() function was called too
    early, the active-tab property was still null.
    
    So now, update sensitivity (and do other stuff) when the
    notify::active-tab signal is sent by the TeplApplicationWindow, so we
    are sure that the active-tab property has the new value.

 src/main_window.vala      |   61 +++++++++++++++++----------------------------
 src/main_window_file.vala |    6 +++-
 2 files changed, 28 insertions(+), 39 deletions(-)
---
diff --git a/src/main_window.vala b/src/main_window.vala
index 4b2c89e..db2ab4a 100644
--- a/src/main_window.vala
+++ b/src/main_window.vala
@@ -161,6 +161,17 @@ public class MainWindow : ApplicationWindow
 
         tepl_window.notify["active-tab"].connect (() =>
         {
+            update_file_actions_sensitivity ();
+            update_config_project_sensitivity ();
+            update_cursor_position_statusbar ();
+            my_set_title ();
+
+            if (this.active_tab == null)
+            {
+                _goto_line.hide ();
+                _search_and_replace.hide ();
+            }
+
             this.notify_property ("active-tab");
         });
 
@@ -186,7 +197,7 @@ public class MainWindow : ApplicationWindow
         _main_window_tools = new MainWindowTools (this, _ui_manager);
 
         show_images_in_menu ();
-        set_file_actions_sensitivity (false);
+        update_file_actions_sensitivity ();
 
         /* Main vertical grid */
 
@@ -465,40 +476,6 @@ public class MainWindow : ApplicationWindow
             Gtk.Menu popup_menu = _ui_manager.get_widget ("/NotebookPopup") as Gtk.Menu;
             popup_menu.popup (null, null, null, event.button, event.time);
         });
-
-        _documents_panel.page_added.connect (() =>
-        {
-            int nb_pages = _documents_panel.get_n_pages ();
-
-            // actions for which there must be 1 document minimum
-            if (nb_pages == 1)
-                set_file_actions_sensitivity (true);
-        });
-
-        _documents_panel.page_removed.connect (() =>
-        {
-            int nb_pages = _documents_panel.get_n_pages ();
-
-            if (nb_pages == 0)
-            {
-                _statusbar.set_cursor_position (-1, -1);
-                set_file_actions_sensitivity (false);
-                _goto_line.hide ();
-                _search_and_replace.hide ();
-            }
-
-            my_set_title ();
-        });
-
-        _documents_panel.switch_page.connect ((pg, page_num) =>
-        {
-            _main_window_edit.update_sensitivity ();
-            _main_window_build_tools.update_sensitivity ();
-            _main_window_tools.update_sensitivity ();
-            update_config_project_sensitivity ();
-            my_set_title ();
-            update_cursor_position_statusbar ();
-        });
     }
 
     private BottomPanel get_bottom_panel ()
@@ -982,7 +959,10 @@ public class MainWindow : ApplicationWindow
     private void update_cursor_position_statusbar ()
     {
         if (active_view == null)
+        {
+            _statusbar.set_cursor_position (-1, -1);
             return;
+        }
 
         TextIter iter;
         active_document.get_iter_at_mark (out iter, active_document.get_insert ());
@@ -1049,9 +1029,13 @@ public class MainWindow : ApplicationWindow
     /*************************************************************************/
     // Sensitivity
 
-    private void set_file_actions_sensitivity (bool sensitive)
+    private void update_file_actions_sensitivity ()
     {
-        // actions that must be insensitive if the notebook is empty
+        Tepl.ApplicationWindow tepl_window =
+            Tepl.ApplicationWindow.get_from_gtk_application_window (this);
+        bool sensitive = tepl_window.active_tab != null;
+
+        // Actions that must be insensitive if the notebook is empty.
         string[] file_actions =
         {
             "ViewZoomIn",
@@ -1071,7 +1055,8 @@ public class MainWindow : ApplicationWindow
         }
 
         _latex_action_group.set_sensitive (sensitive);
-        _main_window_file.update_sensitivity (sensitive);
+
+        _main_window_file.update_sensitivity ();
         _main_window_edit.update_sensitivity ();
         _main_window_build_tools.update_sensitivity ();
         _main_window_tools.update_sensitivity ();
diff --git a/src/main_window_file.vala b/src/main_window_file.vala
index ade3c8e..b0a341f 100644
--- a/src/main_window_file.vala
+++ b/src/main_window_file.vala
@@ -115,8 +115,12 @@ public class MainWindowFile
 
     /* Sensitivity */
 
-    public void update_sensitivity (bool sensitive)
+    public void update_sensitivity ()
     {
+        Tepl.ApplicationWindow tepl_window =
+            Tepl.ApplicationWindow.get_from_gtk_application_window (_main_window);
+        bool sensitive = tepl_window.active_tab != null;
+
         string[] action_names =
         {
             "FileSave",