[gvfs] GVfsJobUnmount: check that vfunc is implemented before calling it

[Tomas Bzatek <tbzatek src gnome org>]

commit e523572e14a9042696e1c5ccd4f30cb3240fa0df
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Tue Feb 7 15:25:05 2012 +0100

    GVfsJobUnmount: check that vfunc is implemented before calling it
    
    GVfsBackend::try_unmount is optional (like all the other try_* vfuncs),
    and in fact many backends don't implement it.
    In case it's NULL, returing FALSE does the right thing and schedules
    a thread for calling ->unmount.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=669211

 daemon/gvfsjobunmount.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/daemon/gvfsjobunmount.c b/daemon/gvfsjobunmount.c
index d31b36e..85873f9 100644
--- a/daemon/gvfsjobunmount.c
+++ b/daemon/gvfsjobunmount.c
@@ -130,6 +130,9 @@ run (GVfsJob *job)
   GVfsJobUnmount *op_job = G_VFS_JOB_UNMOUNT (job);
   GVfsBackendClass *class = G_VFS_BACKEND_GET_CLASS (op_job->backend);
 
+  if (class->unmount == NULL)
+    return;
+
   class->unmount (op_job->backend,
 		  op_job,
                   op_job->flags,
@@ -218,11 +221,13 @@ try (GVfsJob *job)
 
   if (job_finish_immediately_if_possible (op_job))
     return TRUE;
-  else
+  else if (class->try_unmount != NULL)
     return class->try_unmount (op_job->backend,
 			       op_job,
 			       op_job->flags,
 			       op_job->mount_source);
+  else
+    return FALSE;
 }
 
 static void