[gvfs/wip/udisks2] udisks2: handle when g_dbus_interface_get_object() returns NULL

[David Zeuthen <davidz src gnome org>]

commit 51101993ea9c5cb7dabab4ae6cab8621abc8a038
Author: David Zeuthen <davidz redhat com>
Date:   Fri Oct 7 12:15:01 2011 -0400

    udisks2: handle when g_dbus_interface_get_object() returns NULL
    
    Signed-off-by: David Zeuthen <davidz redhat com>

 monitor/udisks2/gvfsudisks2mount.c         |   17 +++++++++++++----
 monitor/udisks2/gvfsudisks2volume.c        |   19 +++++++++++++++----
 monitor/udisks2/gvfsudisks2volumemonitor.c |   11 +++++++++--
 3 files changed, 37 insertions(+), 10 deletions(-)
---
diff --git a/monitor/udisks2/gvfsudisks2mount.c b/monitor/udisks2/gvfsudisks2mount.c
index 1745134..58b341a 100644
--- a/monitor/udisks2/gvfsudisks2mount.c
+++ b/monitor/udisks2/gvfsudisks2mount.c
@@ -910,7 +910,6 @@ gvfs_udisks2_mount_unmount_with_operation (GMount              *_mount,
   GVfsUDisks2Mount *mount = GVFS_UDISKS2_MOUNT (_mount);
   UnmountData *data;
   UDisksBlock *block;
-  UDisksObject *object;
 
   /* first emit the ::mount-pre-unmount signal */
   g_signal_emit_by_name (mount->monitor, "mount-pre-unmount", mount);
@@ -936,13 +935,23 @@ gvfs_udisks2_mount_unmount_with_operation (GMount              *_mount,
   block = gvfs_udisks2_volume_get_block (data->mount->volume);
   if (block != NULL)
     {
-      object = UDISKS_OBJECT (g_dbus_interface_get_object (G_DBUS_INTERFACE (block)));
-      data->filesystem = udisks_object_get_filesystem (object);
+      GDBusObject *object;
+      object = g_dbus_interface_get_object (G_DBUS_INTERFACE (block));
+      if (object == NULL)
+        {
+          g_simple_async_result_set_error (data->simple,
+                                           G_IO_ERROR,
+                                           G_IO_ERROR_FAILED,
+                                           "No object for D-Bus interface");
+          g_simple_async_result_complete (data->simple);
+              unmount_data_free (data);
+        }
+      data->filesystem = udisks_object_get_filesystem (UDISKS_OBJECT (object));
       if (data->filesystem == NULL)
         {
           UDisksBlock *cleartext_block;
 
-          data->encrypted = udisks_object_get_encrypted (object);
+          data->encrypted = udisks_object_get_encrypted (UDISKS_OBJECT (object));
           if (data->encrypted == NULL)
             {
               g_simple_async_result_set_error (data->simple,
diff --git a/monitor/udisks2/gvfsudisks2volume.c b/monitor/udisks2/gvfsudisks2volume.c
index a2a0934..82e2660 100644
--- a/monitor/udisks2/gvfsudisks2volume.c
+++ b/monitor/udisks2/gvfsudisks2volume.c
@@ -1002,7 +1002,7 @@ gvfs_udisks2_volume_mount (GVolume             *_volume,
                            gpointer             user_data)
 {
   GVfsUDisks2Volume *volume = GVFS_UDISKS2_VOLUME (_volume);
-  UDisksObject *object;
+  GDBusObject *object;
   UDisksBlock *block;
   UDisksFilesystem *filesystem;
   MountData *data;
@@ -1042,11 +1042,22 @@ gvfs_udisks2_volume_mount (GVolume             *_volume,
   else
     block = volume->block;
 
-  object = UDISKS_OBJECT (g_dbus_interface_get_object (G_DBUS_INTERFACE (block)));
-  filesystem = udisks_object_peek_filesystem (object);
+  object = g_dbus_interface_get_object (G_DBUS_INTERFACE (block));
+  if (object == NULL)
+    {
+      g_simple_async_result_set_error (data->simple,
+                                       G_IO_ERROR,
+                                       G_IO_ERROR_FAILED,
+                                       "No object for D-Bus interface");
+      g_simple_async_result_complete (data->simple);
+      mount_data_free (data);
+      goto out;
+    }
+
+  filesystem = udisks_object_peek_filesystem (UDISKS_OBJECT (object));
   if (filesystem == NULL)
     {
-      data->encrypted_to_unlock = udisks_object_get_encrypted (object);
+      data->encrypted_to_unlock = udisks_object_get_encrypted (UDISKS_OBJECT (object));
       if (data->encrypted_to_unlock != NULL)
         {
           do_unlock (data);
diff --git a/monitor/udisks2/gvfsudisks2volumemonitor.c b/monitor/udisks2/gvfsudisks2volumemonitor.c
index f6ccc2a..73b305f 100644
--- a/monitor/udisks2/gvfsudisks2volumemonitor.c
+++ b/monitor/udisks2/gvfsudisks2volumemonitor.c
@@ -694,8 +694,15 @@ should_include_drive (GVfsUDisks2VolumeMonitor *monitor,
 static gint
 udisks_drive_compare (UDisksDrive *a, UDisksDrive *b)
 {
-  return g_strcmp0 (g_dbus_object_get_object_path (g_dbus_interface_get_object (G_DBUS_INTERFACE (a))),
-                    g_dbus_object_get_object_path (g_dbus_interface_get_object (G_DBUS_INTERFACE (b))));
+  GDBusObject *oa = g_dbus_interface_get_object (G_DBUS_INTERFACE (a));
+  GDBusObject *ob = g_dbus_interface_get_object (G_DBUS_INTERFACE (b));
+  /* Either or both of oa, ob can be NULL for the case where a drive
+   * is removed but we still hold a reference to the drive interface
+   */
+  if (oa != NULL && ob != NULL)
+    return g_strcmp0 (g_dbus_object_get_object_path (oa), g_dbus_object_get_object_path (ob));
+  else
+    return (const gchar*) ob - (const gchar*) oa;
 }
 
 static gint