[gimp] app: fix crashes by not trying to navigate on a NULL layout

[Michael Natterer <mitch src gnome org>]

commit 8e0dd56feb3aa6deba752aec44f8fde96ae611d7
Author: Michael Natterer <mitch gimp org>
Date:   Thu Oct 14 11:01:16 2010 +0200

    app: fix crashes by not trying to navigate on a NULL layout
    
    Add boolean return value to gimp_text_tool_ensure_layout() and check
    it where needed. Also fix the new VISUAL_POSITIONS navigation code yet
    again.

 app/tools/gimptexttool-editor.c |   37 ++++++++++++++++++-------------------
 app/tools/gimptexttool.c        |    4 +++-
 app/tools/gimptexttool.h        |    2 +-
 3 files changed, 22 insertions(+), 21 deletions(-)
---
diff --git a/app/tools/gimptexttool-editor.c b/app/tools/gimptexttool-editor.c
index 025687f..3fd8d23 100644
--- a/app/tools/gimptexttool-editor.c
+++ b/app/tools/gimptexttool-editor.c
@@ -681,45 +681,43 @@ gimp_text_tool_move_cursor (GimpTextTool    *text_tool,
       if (! cancel_selection)
         {
           PangoLayout *layout;
-          gint         index;
-          gint         trailing;
 
-          index = gimp_text_buffer_get_iter_index (text_tool->buffer,
-                                                   &cursor, TRUE);
+          if (! gimp_text_tool_ensure_layout (text_tool))
+            break;
 
           layout = gimp_text_layout_get_pango_layout (text_tool->layout);
 
           while (count != 0)
             {
+              gint index;
+              gint trailing;
               gint new_index;
 
+              index = gimp_text_buffer_get_iter_index (text_tool->buffer,
+                                                       &cursor, TRUE);
+
              if (count > 0)
                 {
                   pango_layout_move_cursor_visually (layout, TRUE, index, 0, 1,
                                                      &new_index, &trailing);
                   count--;
-
-                  if (new_index != G_MAXINT)
-                    index = new_index;
-                  else
-                    break;
                 }
               else
                 {
                   pango_layout_move_cursor_visually (layout, TRUE, index, 0, -1,
                                                      &new_index, &trailing);
                   count++;
-
-                  if (new_index != -1)
-                    index = new_index;
-                  else
-                    break;
                 }
-            }
 
-          gimp_text_buffer_get_iter_at_index (text_tool->buffer,
-                                              &cursor, index, TRUE);
-          gtk_text_iter_forward_chars (&cursor, trailing);
+             if (new_index != G_MAXINT && new_index != -1)
+               index = new_index;
+             else
+               break;
+
+             gimp_text_buffer_get_iter_at_index (text_tool->buffer,
+                                                 &cursor, index, TRUE);
+             gtk_text_iter_forward_chars (&cursor, trailing);
+            }
         }
       break;
 
@@ -753,7 +751,8 @@ gimp_text_tool_move_cursor (GimpTextTool    *text_tool,
         cursor_index = gimp_text_buffer_get_iter_index (text_tool->buffer,
                                                         &cursor, TRUE);
 
-        gimp_text_tool_ensure_layout (text_tool);
+        if (! gimp_text_tool_ensure_layout (text_tool))
+          break;
 
         layout = gimp_text_layout_get_pango_layout (text_tool->layout);
 
diff --git a/app/tools/gimptexttool.c b/app/tools/gimptexttool.c
index 1d36e0a..c44b2b2 100644
--- a/app/tools/gimptexttool.c
+++ b/app/tools/gimptexttool.c
@@ -1740,7 +1740,7 @@ gimp_text_tool_clear_layout (GimpTextTool *text_tool)
     }
 }
 
-void
+gboolean
 gimp_text_tool_ensure_layout (GimpTextTool *text_tool)
 {
   if (! text_tool->layout && text_tool->text)
@@ -1749,6 +1749,8 @@ gimp_text_tool_ensure_layout (GimpTextTool *text_tool)
 
       text_tool->layout = gimp_text_layout_new (text_tool->layer->text, image);
     }
+
+  return text_tool->layout != NULL;
 }
 
 void
diff --git a/app/tools/gimptexttool.h b/app/tools/gimptexttool.h
index 194a426..b93c29c 100644
--- a/app/tools/gimptexttool.h
+++ b/app/tools/gimptexttool.h
@@ -118,7 +118,7 @@ void       gimp_text_tool_create_vectors_warped  (GimpTextTool *text_tool);
 
 /*  only for the text editor  */
 void       gimp_text_tool_clear_layout           (GimpTextTool *text_tool);
-void       gimp_text_tool_ensure_layout          (GimpTextTool *text_tool);
+gboolean   gimp_text_tool_ensure_layout          (GimpTextTool *text_tool);
 
 
 #endif /* __GIMP_TEXT_TOOL_H__ */