Title: Migrating from GnomeVFS to GIO
SPDX-License-Identifier: LGPL-2.1-or-later
SPDX-FileCopyrightText: 2010 Matthias Clasen

# Migrating from GnomeVFS to GIO

## Comparison of GnomeVFS and GIO concepts

| GnomeVFS | GIO |
|----------|-----|
| `GnomeVFSURI` | [iface@Gio.File] |
| `GnomeVFSFileInfo` | [class@Gio.FileInfo] |
| `GnomeVFSResult` | [struct@GLib.Error], with `G_IO_ERROR` values |
| `GnomeVFSHandle` & `GnomeVFSAsyncHandle` | [class@Gio.InputStream] or [class@Gio.OutputStream] |
| `GnomeVFSDirectoryHandle` | [class@Gio.FileEnumerator] |
| MIME type | content type |
| `GnomeVFSMonitor` | [class@Gio.FileMonitor] |
| `GnomeVFSVolumeMonitor` | [class@Gio.VolumeMonitor] |
| `GnomeVFSVolume` | [iface@Gio.Mount] |
| `GnomeVFSDrive` | [iface@Gio.Volume] |
| - | [iface@Gio.Drive] |
| `GnomeVFSContext` | [class@Gio.Cancellable] |
| `gnome_vfs_async_cancel()` | [method@Gio.Cancellable.cancel] |

## Trash handling

The handling of trashed files has been changed in GIO, compared to
gnome-vfs. gnome-vfs has a home-grown trash implementation that predates the
freedesktop.org [Desktop Trash
Can](http://www.freedesktop.org/wiki/Specifications/trash-spec)
specification that is implemented in GIO.  The location for storing trashed
files has changed from `$HOME/.Trash` to `$HOME/.local/share/Trash` (or more
correctly `$XDG_DATA_HOME/Trash`), which means that there is a need for
migrating files that have been trashed by gnome-vfs to the new location.

In gnome-vfs, the `trash://` scheme offering a merged view of all trash
directories was implemented in Nautilus, and trash-handling applications had
to find and monitor all trash directories themselves. With GIO, the
`trash://` implementation has been moved to gvfs and applications can simply
monitor that location:

```c
static void
file_changed (GFileMonitor      *file_monitor,
              GFile             *child,
              GFile             *other_file,
              GFileMonitorEvent  event_type,
              gpointer           user_data)
{
  switch (event_type)
  {
  case G_FILE_MONITOR_EVENT_DELETED:
    g_print ("'%s' removed from trash\n", g_file_get_basename (child));
    break;
  case G_FILE_MONITOR_EVENT_CREATED:
    g_print ("'%s' added to trash\n", g_file_get_basename (child));
    break;
  default: ;
  }
}

static void
start_monitoring_trash (void)
{
  GFile *file;
  GFileMonitor *monitor;

  file = g_file_new_for_uri ("trash://");
  monitor = g_file_monitor_directory (file, 0, NULL, NULL);
  g_object_unref (file);

  g_signal_connect (monitor, "changed", G_CALLBACK (file_changed), NULL);

  /* ... */

}
```

GIO exposes some useful metadata about trashed files. There are
`trash::orig-path` and `trash::deletion-date` attributes. The
`standard::icon` attribute of the `trash://` itself provides a suitable icon
for displaying the trash can on the desktop. If you are using this icon,
make sure to monitor this attribute for changes, since the icon may be
updated to reflect that state of the trash can.

Moving a file to the trash is much simpler with GIO. Instead of using
`gnome_vfs_find_directory()` with `GNOME_VFS_DIRECTORY_KIND_TRASH` to find
out where to move the trashed file, just use the [`method@Gio.File.trash`]
method.

## Operations on multiple files

gnome-vfs has the dreaded `gnome_vfs_xfer_uri_list()` function which has
tons of options and offers the equivalent of `cp`, `mv`, `ln`, `mkdir` and
`rm` at the same time.

GIO offers a much simpler asynchronous task functionality instead, that lets
you schedule a function to be called in a separate thread, making sure that
updates are scheduled within the main context that created the task, so you
can update your user interface. See: [`class@Gio.Task`].

## Mime monitoring

gnome-vfs offered a way to monitor the association between mime types and
default handlers for changes, with the `GnomeVFSMIMEMonitor` object. GIO
does not offer a replacement for this functionality at this time, since we
have not found a compelling use case where `GnomeVFSMIMEMonitor` was used.
If you think you have such a use case, please [open an issue on the GLib
issue tracker](https://gitlab.gnome.org/GNOME/glib/issues/new).