[glib] g_file_copy: Fall back to pathname queryinfo to help gvfs backends

[Colin Walters <walters src gnome org>]

commit be2656f13952dd22d348ff5e3f43240700cdef5a
Author: Colin Walters <walters verbum org>
Date:   Wed Oct 16 10:10:22 2013 -0400

    g_file_copy: Fall back to pathname queryinfo to help gvfs backends
    
    It's not difficult to do; not all backends implement it, and for some
    it may be difficult to implement query_info_on_read(), so let's just
    do both.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706254

 gio/gfile.c |   23 ++++++++++++++++++++++-
 1 files changed, 22 insertions(+), 1 deletions(-)
---
diff --git a/gio/gfile.c b/gio/gfile.c
index afaee21..bf936ec 100644
--- a/gio/gfile.c
+++ b/gio/gfile.c
@@ -3112,6 +3112,8 @@ file_copy_fallback (GFile                  *source,
 
   if (attrs_to_read != NULL)
     {
+      GError *tmp_error = NULL;
+
       /* Ok, ditch the previous lightweight info (on Unix we just
        * called lstat()); at this point we gather all the information
        * we need about the source from the opened file descriptor.
@@ -3119,7 +3121,26 @@ file_copy_fallback (GFile                  *source,
       g_object_unref (info);
 
       info = g_file_input_stream_query_info (file_in, attrs_to_read,
-                                             cancellable, error);
+                                             cancellable, &tmp_error);
+      if (!info)
+        {
+          /* Not all gvfs backends implement query_info_on_read(), we
+           * can just fall back to the pathname again.
+           * https://bugzilla.gnome.org/706254
+           */
+          if (g_error_matches (tmp_error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED))
+            {
+              g_clear_error (&tmp_error);
+              info = g_file_query_info (source, attrs_to_read, G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
+                                        cancellable, error);
+            }
+          else
+            {
+              g_free (attrs_to_read);
+              g_propagate_error (error, tmp_error);
+              goto out;
+            }
+        }
       g_free (attrs_to_read);
       if (!info)
         goto out;