[nautilus/1841-crashing-when-copying-folder-with-same-name-and-click-to-rename: 1/2] file-conflict-dialog: Fix crash on extensionless filenames

[António Fernandes <antoniof src gnome org>]

commit 4a99c7e15a1349172ca4593b14b4851ce6aef93f
Author: António Fernandes <antoniof gnome org>
Date:   Thu Apr 29 16:36:47 2021 +0100

    file-conflict-dialog: Fix crash on extensionless filenames
    
    The new filename entry has the automatically suggested part of the name
    selected for convenience since 9108b4028b7f476b598bc664079fd6d115801b66
    
    However, the logic for this relies on extensions offsets, causing
    crashes when failing to handle the extensionless case, which is common
    for folders.
    
    So, improve the logic here to handle extensionless filenames, looking
    at their length instead.
    
    Fixes https://gitlab.gnome.org/GNOME/nautilus/-/issues/1841

 src/nautilus-file-conflict-dialog.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)
---
diff --git a/src/nautilus-file-conflict-dialog.c b/src/nautilus-file-conflict-dialog.c
index 28fa972a3..4fe195e17 100644
--- a/src/nautilus-file-conflict-dialog.c
+++ b/src/nautilus-file-conflict-dialog.c
@@ -191,6 +191,23 @@ entry_text_changed_cb (GtkEditable                *entry,
     }
 }
 
+static int
+get_character_position_after_basename (const gchar *filename)
+{
+    const gchar *extension;
+
+    extension = eel_filename_get_extension_offset (filename);
+
+    if (extension == NULL)
+    {
+        /* If filename has got no extension, we want to get the index of the
+         * terminating null byte comes after the basename. */
+        return (int) g_utf8_strlen (filename);
+    }
+
+    return g_utf8_pointer_to_offset (filename, extension);
+}
+
 static void
 on_expanded_notify (GtkExpander                *w,
                     GParamSpec                 *pspec,
@@ -212,15 +229,11 @@ on_expanded_notify (GtkExpander                *w,
              * replace the "(1)" bits with with something more meaningful, so
              * select this region for convenience. */
 
-            const gchar *offset;
             int start_pos;
             int end_pos;
 
-            offset = eel_filename_get_extension_offset (dialog->conflict_name);
-            start_pos = g_utf8_pointer_to_offset (dialog->conflict_name, offset);
-
-            offset = eel_filename_get_extension_offset (dialog->suggested_name);
-            end_pos = g_utf8_pointer_to_offset (dialog->suggested_name, offset);
+            start_pos = get_character_position_after_basename (dialog->conflict_name);
+            end_pos = get_character_position_after_basename (dialog->suggested_name);
 
             gtk_editable_select_region (GTK_EDITABLE (dialog->entry), start_pos, end_pos);
         }