[latexila] Document: check if tab != null

[Sébastien Wilmet <swilmet src gnome org>]

commit cba23f861067a1769605865f4d6e482806b7b8aa
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sat Mar 4 13:44:59 2017 +0100

    Document: check if tab != null
    
    Since it's now a weak ref.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=761181

 src/document.vala |   38 +++++++++++++++++++++++++++-----------
 1 files changed, 27 insertions(+), 11 deletions(-)
---
diff --git a/src/document.vala b/src/document.vala
index 4a888ab..5088cd1 100644
--- a/src/document.vala
+++ b/src/document.vala
@@ -58,8 +58,13 @@ public class Document : Gtef.Buffer
 
     public new void insert (ref TextIter iter, string text, int len)
     {
-        Gtk.SourceCompletion completion = tab.view.completion;
-        completion.block_interactive ();
+        Gtk.SourceCompletion? completion = null;
+
+        if (tab != null)
+        {
+            completion = tab.view.completion;
+            completion.block_interactive ();
+        }
 
         base.insert (ref iter, text, len);
 
@@ -67,7 +72,9 @@ public class Document : Gtef.Buffer
         // Utils.flush_queue ().
         Timeout.add_seconds (1, () =>
         {
-            completion.unblock_interactive ();
+            if (completion != null)
+                completion.unblock_interactive ();
+
             return false;
         });
     }
@@ -112,9 +119,12 @@ public class Document : Gtef.Buffer
         {
             warning ("%s", e.message);
 
-            string primary_msg = _("Impossible to load the file '%s'.")
-                .printf (location.get_parse_name ());
-            tab.add_message (primary_msg, e.message, MessageType.ERROR);
+            if (tab != null)
+            {
+                string primary_msg = _("Impossible to load the file '%s'.")
+                    .printf (location.get_parse_name ());
+                tab.add_message (primary_msg, e.message, MessageType.ERROR);
+            }
         }
     }
 
@@ -188,7 +198,7 @@ public class Document : Gtef.Buffer
         }
         catch (Error e)
         {
-            if (e is IOError.WRONG_ETAG)
+            if (e is IOError.WRONG_ETAG && tab != null)
             {
                 string primary_msg = _("The file %s has been modified since reading it.")
                     .printf (location.get_parse_name ());
@@ -209,10 +219,13 @@ public class Document : Gtef.Buffer
             {
                 warning ("%s", e.message);
 
-                string primary_msg = _("Impossible to save the file.");
-                Gtef.InfoBar infobar = tab.add_message (primary_msg, e.message,
-                    MessageType.ERROR);
-                infobar.add_close_button ();
+                if (tab != null)
+                {
+                    string primary_msg = _("Impossible to save the file.");
+                    Gtef.InfoBar infobar = tab.add_message (primary_msg, e.message,
+                        MessageType.ERROR);
+                    infobar.add_close_button ();
+                }
             }
         }
     }
@@ -499,6 +512,9 @@ public class Document : Gtef.Buffer
 
         /* Warn the user that the file can be lost */
 
+        if (tab == null)
+            return true;
+
         Gtef.InfoBar infobar = tab.add_message (
             _("The file has a temporary location. The data can be lost after rebooting your computer."),
             _("Do you want to save the file in a safer place?"),