## GVolume

GVolume — Volume management

## Synopsis

    #include <gio/gio.h>

                        GVolume;
                        GVolumeIface;
    char *              g_volume_get_name                   (GVolume *volume);
    char *              g_volume_get_uuid                   (GVolume *volume);
    GIcon *             g_volume_get_icon                   (GVolume *volume);
    GDrive *            g_volume_get_drive                  (GVolume *volume);
    GMount *            g_volume_get_mount                  (GVolume *volume);
    gboolean            g_volume_can_mount                  (GVolume *volume);
    gboolean            g_volume_should_automount           (GVolume *volume);
    GFile *             g_volume_get_activation_root        (GVolume *volume);
    void                g_volume_mount                      (GVolume *volume,
                                                             GMountMountFlags flags,
                                                             GMountOperation *mount_operation,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);
    gboolean            g_volume_mount_finish               (GVolume *volume,
                                                             GAsyncResult *result,
                                                             GError **error);
    gboolean            g_volume_can_eject                  (GVolume *volume);
    void                g_volume_eject                      (GVolume *volume,
                                                             GMountUnmountFlags flags,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);
    gboolean            g_volume_eject_finish               (GVolume *volume,
                                                             GAsyncResult *result,
                                                             GError **error);
    #define             G_VOLUME_IDENTIFIER_KIND_HAL_UDI
    #define             G_VOLUME_IDENTIFIER_KIND_LABEL
    #define             G_VOLUME_IDENTIFIER_KIND_NFS_MOUNT
    #define             G_VOLUME_IDENTIFIER_KIND_UNIX_DEVICE
    #define             G_VOLUME_IDENTIFIER_KIND_UUID
    char **             g_volume_enumerate_identifiers      (GVolume *volume);
    char *              g_volume_get_identifier             (GVolume *volume,
                                                             const char *kind);

## Object Hierarchy

      GInterface
       +----GVolume

## Prerequisites

GVolume requires GObject.

## Signals

      "changed"                                        : Run Last
      "removed"                                        : Run Last

## Description

The GVolume interface represents user-visible objects that can be mounted. Note, when porting from GnomeVFS, GVolume is the moral equivalent of GnomeVFSDrive.

Mounting a GVolume instance is an asynchronous operation. For more information about asynchronous operations, see GAsyncReady and GSimpleAsyncReady. To mount a GVolume, first call `g_volume_mount()` with (at least) the GVolume instance, optionally a GMountOperation object and a GAsyncReadyCallback.

Typically, one will only want to pass `NULL` for the GMountOperation if automounting all volumes when a desktop session starts since it's not desirable to put up a lot of dialogs asking for credentials.

The callback will be fired when the operation has resolved (either with success or failure), and a GAsyncReady structure will be passed to the callback. That callback should then call `g_volume_mount_finish()` with the GVolume instance and the GAsyncReady data to see if the operation was completed successfully. If an `error` is present when `g_volume_mount_finish()` is called, then it will be filled with any error information.

It is sometimes necessary to directly access the underlying operating system object behind a volume (e.g. for passing a volume to an application via the commandline). For this purpose, GIO allows to obtain an 'identifier' for the volume. There can be different kinds of identifiers, such as Hal UDIs, filesystem labels, traditional Unix devices (e.g. `/dev/sda2`), uuids. GIO uses predefind strings as names for the different kinds of identifiers: G_VOLUME_IDENTIFIER_KIND_HAL_UDI, G_VOLUME_IDENTIFIER_KIND_LABEL, etc. Use `g_volume_get_identifier()` to obtain an identifier for a volume.

## Details

### GVolume

    typedef struct _GVolume GVolume;

Opaque mountable volume object.

### GVolumeIface

    typedef struct {
      GTypeInterface g_iface;

      /* signals */

      void        (* changed)               (GVolume             *volume);
      void        (* removed)               (GVolume             *volume);

      /* Virtual Table */

      char      * (* get_name)              (GVolume             *volume);
      GIcon     * (* get_icon)              (GVolume             *volume);
      char      * (* get_uuid)              (GVolume             *volume);
      GDrive    * (* get_drive)             (GVolume             *volume);
      GMount    * (* get_mount)             (GVolume             *volume);
      gboolean    (* can_mount)             (GVolume             *volume);
      gboolean    (* can_eject)             (GVolume             *volume);
      void        (* mount_fn)              (GVolume             *volume,
                                             GMountMountFlags     flags,
                                             GMountOperation     *mount_operation,
                                             GCancellable        *cancellable,
                                             GAsyncReadyCallback  callback,
                                             gpointer             user_data);
      gboolean    (* mount_finish)          (GVolume             *volume,
                                             GAsyncResult        *result,
                                             GError             **error);
      void        (* eject)                 (GVolume             *volume,
                                             GMountUnmountFlags   flags,
                                             GCancellable        *cancellable,
                                             GAsyncReadyCallback  callback,
                                             gpointer             user_data);
      gboolean    (* eject_finish)          (GVolume             *volume,
                                             GAsyncResult        *result,
                                             GError             **error);

      char      * (* get_identifier)        (GVolume             *volume,
                                             const char          *kind);
      char     ** (* enumerate_identifiers) (GVolume             *volume);

      gboolean    (* should_automount)      (GVolume             *volume);

      GFile     * (* get_activation_root)   (GVolume             *volume);
    } GVolumeIface;

Interface for implementing operations for mountable volumes.

GTypeInterface `g_iface`; | The parent interface.
`changed` () | Changed signal that is emitted when the volume's state has changed.
`removed` () | The removed signal that is emitted when the GVolume have been removed. If the recipient is holding references to the object they should release them so the object can be finalized.
`get_name` () | Gets a string containing the name of the GVolume.
`get_icon` () | Gets a GIcon for the GVolume.
`get_uuid` () | Gets the UUID for the GVolume. The reference is typically based on the file system UUID for the mount in question and should be considered an opaque string. Returns `NULL` if there is no UUID available.
`get_drive` () | Gets a GDrive the volume is located on. Returns `NULL` if the GVolume is not associated with a GDrive.
`get_mount` () | Gets a GMount representing the mounted volume. Returns `NULL` if the GVolume is not mounted.
`can_mount` () | Returns `TRUE` if the GVolume can be mounted.
`can_eject` () | Checks if a GVolume can be ejected.
`mount_fn` () | Mounts a given GVolume.
`mount_finish` () | Finishes a mount operation.
`eject` () | Ejects a given GVolume.
`eject_finish` () | Finishes an eject operation.
`get_identifier` () | Returns the identifier of the given kind, or `NULL` if the GVolume doesn't have one.
`enumerate_identifiers` () | Returns an array strings listing the kinds of identifiers which the GVolume has.
`should_automount` () | Returns `TRUE` if the GVolume should be automatically mounted.
`get_activation_root` () | Returns the activation root for the GVolume if it is known in advance or `NULL` if it is not known.

### g_volume_get_name ()

    char *              g_volume_get_name                   (GVolume *volume);

Gets the name of `volume`.

`volume` : | a GVolume.
Returns : | the name for the given `volume`. The returned string should be freed with `g_free()` when no longer needed.

### g_volume_get_uuid ()

    char *              g_volume_get_uuid                   (GVolume *volume);

Gets the UUID for the `volume`. The reference is typically based on the file system UUID for the volume in question and should be considered an opaque string. Returns `NULL` if there is no UUID available.

`volume` : | a GVolume.
Returns : | the UUID for `volume` or `NULL` if no UUID can be computed. The returned string should be freed with `g_free()` when no longer needed.

### g_volume_get_icon ()

    GIcon *             g_volume_get_icon                   (GVolume *volume);

Gets the icon for `volume`.

`volume` : | a GVolume.
Returns : | a GIcon. The returned object should be unreffed with `g_object_unref()` when no longer needed.

### g_volume_get_drive ()

    GDrive *            g_volume_get_drive                  (GVolume *volume);

Gets the drive for the `volume`.

`volume` : | a GVolume.
Returns : | a GDrive or `NULL` if `volume` is not associated with a drive. The returned object should be unreffed with `g_object_unref()` when no longer needed.

### g_volume_get_mount ()

    GMount *            g_volume_get_mount                  (GVolume *volume);

Gets the mount for the `volume`.

`volume` : | a GVolume.
Returns : | a GMount or `NULL` if `volume` isn't mounted. The returned object should be unreffed with `g_object_unref()` when no longer needed.

### g_volume_can_mount ()

    gboolean            g_volume_can_mount                  (GVolume *volume);

Checks if a volume can be mounted.

`volume` : | a GVolume.
Returns : | `TRUE` if the `volume` can be mounted. `FALSE` otherwise.

### g_volume_should_automount ()

    gboolean            g_volume_should_automount           (GVolume *volume);

Returns whether the volume should be automatically mounted.

`volume` : | a GVolume
Returns : | `TRUE` if the volume should be automatically mounted.

### g_volume_get_activation_root ()

    GFile *             g_volume_get_activation_root        (GVolume *volume);

Gets the activation root for a GVolume if it is known ahead of mount time. Returns `NULL` otherwise. If not `NULL` and if `volume` is mounted, then the result of `g_mount_get_root()` on the GMount object obtained from `g_volume_get_mount()` will always either be equal or a prefix of what this function returns. In other words, in code

      GMount *mount;
      GFile *mount_root
      GFile *volume_activation_root;

      mount = g_volume_get_mount (volume); /* mounted, so never NULL */
      mount_root = g_mount_get_root (mount);
      volume_activation_root = g_volume_get_activation_root(volume); /* assume not NULL */

then the expression

      (g_file_has_prefix (volume_activation_root, mount_root) ||
          g_file_equal (volume_activation_root, mount_root))

will always be `TRUE`.

There is a number of possible uses of this function.

First, implementations of GVolumeMonitor can use this method to determine if a GMount should be adopted in the implementation of `g_volume_monitor_adopt_orphan_mount()` by testing if the result of this function equals (or has as prefix) the root of the given GMount. In particular this is useful in the in-process proxy part of an out-of-process volume monitor implementation.

Second, applications such as a file manager can use this to navigate to the correct root in response to the user navigating to a server. Now suppose there is a volume monitor for networked servers that creates GVolume objects corresponding to the "favorite servers" (e.g. set up by the user via some "Connect to Server" dialog). Suppose also that one of the favorite servers is named "public_html @ fd.o" and the URI is `sftp://people.freedesktop.org/home/david/public_html`.

Now, due to the way GIO works, when the corresponding GVolume is mounted then a GMount (typically adopted by the volume monitor) will appear with the mount root (e.g. the result of `g_mount_get_root()`) `sftp://people.freedesktop.org`. However, this function (`g_volume_get_activation_root()`) can return a GFile for the URI `sftp://people.freedesktop.org/home/david/public_html`.

All this means that a file manager can use the latter URI for navigating when the user clicks an icon representing the GVolume (e.g. clicking an icon with the name "public_html @ fd.o" or similar).

`volume` : | a GVolume
Returns : | the activation root of `volume` or `NULL`. Use `g_object_unref()` to free.

Since 2.18

### g_volume_mount ()

    void                g_volume_mount                      (GVolume *volume,
                                                             GMountMountFlags flags,
                                                             GMountOperation *mount_operation,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);

Mounts a volume. This is an asynchronous operation, and is finished by calling `g_volume_mount_finish()` with the `volume` and GAsyncResult returned in the `callback`.

`volume` : | a GVolume.
`flags` : | flags affecting the operation
`mount_operation` : | a GMountOperation or `NULL` to avoid user interaction.
`cancellable` : | optional GCancellable object, `NULL` to ignore.
`callback` : | a GAsyncReadyCallback, or `NULL`.
`user_data` : | user data that gets passed to `callback`

### g_volume_mount_finish ()

    gboolean            g_volume_mount_finish               (GVolume *volume,
                                                             GAsyncResult *result,
                                                             GError **error);

Finishes mounting a volume. If any errors occured during the operation, `error` will be set to contain the errors and `FALSE` will be returned.

`volume` : | a GVolume
`result` : | a GAsyncResult
`error` : | a GError location to store an error, or `NULL` to ignore
Returns : | `TRUE`, `FALSE` if operation failed.

### g_volume_can_eject ()

    gboolean            g_volume_can_eject                  (GVolume *volume);

Checks if a volume can be ejected.

`volume` : | a GVolume.
Returns : | `TRUE` if the `volume` can be ejected. `FALSE` otherwise.

### g_volume_eject ()

    void                g_volume_eject                      (GVolume *volume,
                                                             GMountUnmountFlags flags,
                                                             GCancellable *cancellable,
                                                             GAsyncReadyCallback callback,
                                                             gpointer user_data);

Ejects a volume. This is an asynchronous operation, and is finished by calling `g_volume_eject_finish()` with the `volume` and GAsyncResult returned in the `callback`.

`volume` : | a GVolume.
`flags` : | flags affecting the unmount if required for eject
`cancellable` : | optional GCancellable object, `NULL` to ignore.
`callback` : | a GAsyncReadyCallback, or `NULL`.
`user_data` : | user data that gets passed to `callback`

### g_volume_eject_finish ()

    gboolean            g_volume_eject_finish               (GVolume *volume,
                                                             GAsyncResult *result,
                                                             GError **error);

Finishes ejecting a volume. If any errors occured during the operation, `error` will be set to contain the errors and `FALSE` will be returned.

`volume` : | pointer to a GVolume.
`result` : | a GAsyncResult.
`error` : | a GError location to store an error, or `NULL` to ignore
Returns : | `TRUE`, `FALSE` if operation failed.

### G_VOLUME_IDENTIFIER_KIND_HAL_UDI

    #define G_VOLUME_IDENTIFIER_KIND_HAL_UDI "hal-udi"

The string used to obtain a Hal UDI with `g_volume_get_identifier()`.

### G_VOLUME_IDENTIFIER_KIND_LABEL

    #define G_VOLUME_IDENTIFIER_KIND_LABEL "label"

The string used to obtain a filesystem label with `g_volume_get_identifier()`.

### G_VOLUME_IDENTIFIER_KIND_NFS_MOUNT

    #define G_VOLUME_IDENTIFIER_KIND_NFS_MOUNT "nfs-mount"

The string used to obtain a NFS mount with `g_volume_get_identifier()`.

### G_VOLUME_IDENTIFIER_KIND_UNIX_DEVICE

    #define G_VOLUME_IDENTIFIER_KIND_UNIX_DEVICE "unix-device"

The string used to obtain a Unix device path with `g_volume_get_identifier()`.

### G_VOLUME_IDENTIFIER_KIND_UUID

    #define G_VOLUME_IDENTIFIER_KIND_UUID "uuid"

The string used to obtain a UUID with `g_volume_get_identifier()`.

### g_volume_enumerate_identifiers ()

    char **             g_volume_enumerate_identifiers      (GVolume *volume);

Gets the kinds of identifiers that `volume` has. Use `g_volume_get_identifer()` to obtain the identifiers themselves.

`volume` : | a GVolume
Returns : | a `NULL`-terminated array of strings containing kinds of identifiers. Use `g_strfreev()` to free.

### g_volume_get_identifier ()

    char *              g_volume_get_identifier             (GVolume *volume,
                                                             const char *kind);

Gets the identifier of the given kind for `volume`. See the introduction for more information about volume identifiers.

`volume` : | a GVolume
`kind` : | the kind of identifier to return
Returns : | a newly allocated string containing the requested identfier, or `NULL` if the GVolume doesn't have this kind of identifier

## Signal Details

### The `"changed"` signal

    void                user_function                      (GVolume *arg0,
                                                            gpointer user_data)      : Run Last

Emitted when the volume has been changed.

`user_data` : | user data set when the signal handler was connected.

### The `"removed"` signal

    void                user_function                      (GVolume *arg0,
                                                            gpointer user_data)      : Run Last

This signal is emitted when the GVolume have been removed. If the recipient is holding references to the object they should release them so the object can be finalized.

`user_data` : | user data set when the signal handler was connected.