GFileAttribute

GFileAttribute — Key-Value Paired File Attributes

Synopsis

#include <gio/gio.h>

enum                GFileAttributeType;
enum                GFileAttributeInfoFlags;
enum                GFileAttributeStatus;
                    GFileAttributeInfo;
                    GFileAttributeInfoList;
GFileAttributeInfoList * g_file_attribute_info_list_new (void);
GFileAttributeInfoList * g_file_attribute_info_list_ref (GFileAttributeInfoList *list);
void                g_file_attribute_info_list_unref    (GFileAttributeInfoList *list);
GFileAttributeInfoList * g_file_attribute_info_list_dup (GFileAttributeInfoList *list);
const GFileAttributeInfo * g_file_attribute_info_list_lookup
                                                        (GFileAttributeInfoList *list,
                                                         const char *name);
void                g_file_attribute_info_list_add      (GFileAttributeInfoList *list,
                                                         const char *name,
                                                         GFileAttributeType type,
                                                         GFileAttributeInfoFlags flags);

Object Hierarchy

  GEnum
   +----GFileAttributeType
  GFlags
   +----GFileAttributeInfoFlags
  GEnum
   +----GFileAttributeStatus

Description

File attributes in GIO consist of a list of key-value pairs.

Keys are strings that contain a key namespace and a key name, separated by a colon, e.g. "namespace:keyname". Namespaces are included to sort key-value pairs by namespaces for relevance. Keys can be retrived using wildcards, e.g. "standard::*" will return all of the keys in the "standard" namespace.

Values are stored within the list in GFileAttributeValue structures. Values can store different types, listed in the enum GFileAttributeType. Upon creation of a GFileAttributeValue, the type will be set to G_FILE_ATTRIBUTE_TYPE_INVALID.

The list of possible attributes for a filesystem (pointed to by a GFile) is availible as a GFileAttributeInfoList. This list is queryable by key names as indicated earlier.

Classes that implement GFileIface will create a GFileAttributeInfoList and install default keys and values for their given file system, architecture, and other possible implementation details (e.g., on a UNIX system, a file attribute key will be registered for the user id for a given file).

Table 1. GFileAttributes Default Namespaces

Namspace Description
"standard" The "Standard" namespace. General file information that any application may need should be put in this namespace. Examples include the file's name, type, and size.
"etag" The "Entity Tag" namespace. Currently, the only key in this namespace is "value", which contains the value of the current entity tag.
"id" The "Identification" namespace. This namespace is used by file managers and applications that list directories to check for loops and to uniquely identify files.
"access" The "Access" namespace. Used to check if a user has the proper privilidges to access files and perform file operations. Keys in this namespace are made to be generic and easily understood, e.g. the "can_read" key is TRUE if the current user has permission to read the file. UNIX permissions and NTFS ACLs in Windows should be mapped to these values.
"mountable" The "Mountable" namespace. Includes simple boolean keys for checking if a file or path supports mount operations, e.g. mount, unmount, eject. These are used for files of type G_FILE_TYPE_MOUNTABLE.
"time" The "Time" namespace. Includes file access, changed, created times.
"unix" The "Unix" namespace. Includes UNIX-specific information and may not be available for all files. Examples include the UNIX "UID", "GID", etc.
"dos" The "DOS" namespace. Includes DOS-specific information and may not be available for all files. Examples include "is_system" for checking if a file is marked as a system file, and "is_archive" for checking if a file is marked as an archive file.
"owner" The "Owner" namespace. Includes information about who owns a file. May not be available for all file systems. Examples include "user" for getting the user name of the file owner. This information is often mapped from some backend specific data such as a unix UID.
"thumbnail" The "Thumbnail" namespace. Includes information about file thumbnails and their location within the file system. Exaples of keys in this namespace include "path" to get the location of a thumbnail, and "failed" to check if thumbnailing of the file failed.
"filesystem" The "Filesystem" namespace. Gets information about the file system where a file is located, such as its type, how much space is left available, and the overall size of the file system.
"gvfs" The "GVFS" namespace. Keys in this namespace contain information about the current GVFS backend in use.
"xattr" The "xattr" namespace. Gets information about extended user attributes. See attr(5). The "user." prefix of the extended user attribute name is stripped away when constructing keys in this namespace, e.g. "xattr::mime_type" for the extended attribute with the name "user.mime_type". Note that this information is only available if GLib has been built with extended attribute support.
"xattr-sys" The "xattr-sys" namespace. Gets information about extended attributes which are not user-specific. See attr(5). Note that this information is only available if GLib has been built with extended attribute support.
"selinux" The "SELinux" namespace. Includes information about the SELinux context of files. Note that this information is only available if GLib has been built with SELinux support.


Please note that these are not all of the possible namespaces. More namespaces can be added from GIO modules or by individual applications. For more information about writing GIO modules, see GIOModule.

Table 2. GFileAttributes Built-in Keys and Value Types

Enum Value Namespace:Key Value Type
G_FILE_ATTRIBUTE_STANDARD_TYPE standard::type uint32 (GFileType)
G_FILE_ATTRIBUTE_STANDARD_IS_HIDDEN standard::is-hidden boolean
G_FILE_ATTRIBUTE_STANDARD_IS_BACKUP standard::is-backup boolean
G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK standard::is-symlink boolean
G_FILE_ATTRIBUTE_STANDARD_IS_VIRTUAL standard::is-virtual boolean
G_FILE_ATTRIBUTE_STANDARD_NAME standard::name byte string
G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME standard::display-name string
G_FILE_ATTRIBUTE_STANDARD_EDIT_NAME standard::edit-name string
G_FILE_ATTRIBUTE_STANDARD_ICON standard::icon object (GIcon)
G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE standard::content-type string
G_FILE_ATTRIBUTE_STANDARD_FAST_CONTENT_TYPE standard::fast-content-type string
G_FILE_ATTRIBUTE_STANDARD_SIZE standard::size uint64
G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE standard::allocated-size uint64
G_FILE_ATTRIBUTE_STANDARD_SYMLINK_TARGET standard::symlink-target byte string
G_FILE_ATTRIBUTE_STANDARD_TARGET_URI standard::target-uri string
G_FILE_ATTRIBUTE_STANDARD_SORT_ORDER standard::sort-order int32
G_FILE_ATTRIBUTE_ETAG_VALUE etag::value string
G_FILE_ATTRIBUTE_ID_FILE id::file string
G_FILE_ATTRIBUTE_ID_FILESYSTEM id::filesystem string
G_FILE_ATTRIBUTE_ACCESS_CAN_READ access::can-read boolean
G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE access::can-write boolean
G_FILE_ATTRIBUTE_ACCESS_CAN_EXECUTE access::can-execute boolean
G_FILE_ATTRIBUTE_ACCESS_CAN_DELETE access::can-delete boolean
G_FILE_ATTRIBUTE_ACCESS_CAN_TRASH access::can-trash boolean
G_FILE_ATTRIBUTE_ACCESS_CAN_RENAME access::can-rename boolean
G_FILE_ATTRIBUTE_MOUNTABLE_CAN_MOUNT mountable::can-mount boolean
G_FILE_ATTRIBUTE_MOUNTABLE_CAN_UNMOUNT mountable::can-unmount boolean
G_FILE_ATTRIBUTE_MOUNTABLE_CAN_EJECT mountable::can-eject boolean
G_FILE_ATTRIBUTE_MOUNTABLE_UNIX_DEVICE mountable::unix-device uint32
G_FILE_ATTRIBUTE_MOUNTABLE_HAL_UDI mountable::hal-udi string
G_FILE_ATTRIBUTE_TIME_MODIFIED time::modified uint64
G_FILE_ATTRIBUTE_TIME_MODIFIED_USEC time::modified-usec uint32
G_FILE_ATTRIBUTE_TIME_ACCESS time::access uint64
G_FILE_ATTRIBUTE_TIME_ACCESS_USEC time::access-usec uint32
G_FILE_ATTRIBUTE_TIME_CHANGED time::changed uint64
G_FILE_ATTRIBUTE_TIME_CHANGED_USEC time::changed-usec uint32
G_FILE_ATTRIBUTE_TIME_CREATED time::created uint64
G_FILE_ATTRIBUTE_TIME_CREATED_USEC time::created-usec uint32
G_FILE_ATTRIBUTE_UNIX_DEVICE unix::device uint32
G_FILE_ATTRIBUTE_UNIX_INODE unix::inode uint64
G_FILE_ATTRIBUTE_UNIX_MODE unix::mode uint32
G_FILE_ATTRIBUTE_UNIX_NLINK unix::nlink uint32
G_FILE_ATTRIBUTE_UNIX_UID unix::uid uint32
G_FILE_ATTRIBUTE_UNIX_GID unix::gid uint32
G_FILE_ATTRIBUTE_UNIX_RDEV unix::rdev uint32
G_FILE_ATTRIBUTE_UNIX_BLOCK_SIZE unix::block-size uint32
G_FILE_ATTRIBUTE_UNIX_BLOCKS unix::blocks uint64
G_FILE_ATTRIBUTE_UNIX_IS_MOUNTPOINT unix::is-mountpoint boolean
G_FILE_ATTRIBUTE_DOS_IS_ARCHIVE dos::is-archive boolean
G_FILE_ATTRIBUTE_DOS_IS_SYSTEM dos::is-system boolean
G_FILE_ATTRIBUTE_OWNER_USER owner::user string
G_FILE_ATTRIBUTE_OWNER_USER_REAL owner::user-real string
G_FILE_ATTRIBUTE_OWNER_GROUP owner::group string
G_FILE_ATTRIBUTE_THUMBNAIL_PATH thumbnail::path bytestring
G_FILE_ATTRIBUTE_THUMBNAILING_FAILED thumbnail::failed boolean
G_FILE_ATTRIBUTE_PREVIEW_ICON preview::icon object (GIcon)
G_FILE_ATTRIBUTE_FILESYSTEM_SIZE filesystem::size uint64
G_FILE_ATTRIBUTE_FILESYSTEM_FREE filesystem::free uint64
G_FILE_ATTRIBUTE_FILESYSTEM_TYPE filesystem::type string
G_FILE_ATTRIBUTE_FILESYSTEM_READONLY filesystem::readonly boolean
G_FILE_ATTRIBUTE_GVFS_BACKEND gvfs::backend string
G_FILE_ATTRIBUTE_SELINUX_CONTEXT selinux::context string


Note that there are no predefined keys in the "xattr" and "xattr-sys" namespaces. Keys for the "xattr" namespace are constructed by stripping away the "user." prefix from the extended user attribute, and prepending "xattr::". Keys for the "xattr-sys" namespace are constructed by concatenating "xattr-sys::" with the extended attribute name. All extended attribute values are returned as hex-encoded strings in which bytes outside the ASCII range are encoded as hexadecimal escape sequences of the form \xnn.

Details

enum GFileAttributeType

typedef enum {
  G_FILE_ATTRIBUTE_TYPE_INVALID = 0,
  G_FILE_ATTRIBUTE_TYPE_STRING,
  G_FILE_ATTRIBUTE_TYPE_BYTE_STRING, /* zero terminated string of non-zero bytes */
  G_FILE_ATTRIBUTE_TYPE_BOOLEAN,
  G_FILE_ATTRIBUTE_TYPE_UINT32,
  G_FILE_ATTRIBUTE_TYPE_INT32,
  G_FILE_ATTRIBUTE_TYPE_UINT64,
  G_FILE_ATTRIBUTE_TYPE_INT64,
  G_FILE_ATTRIBUTE_TYPE_OBJECT
} GFileAttributeType;

The data types for file attributes.

G_FILE_ATTRIBUTE_TYPE_INVALID

indicates an invalid or uninitalized type.

G_FILE_ATTRIBUTE_TYPE_STRING

a null terminated UTF8 string.

G_FILE_ATTRIBUTE_TYPE_BYTE_STRING

a zero terminated string of non-zero bytes.

G_FILE_ATTRIBUTE_TYPE_BOOLEAN

a boolean value.

G_FILE_ATTRIBUTE_TYPE_UINT32

an unsigned 4-byte/32-bit integer.

G_FILE_ATTRIBUTE_TYPE_INT32

a signed 4-byte/32-bit integer.

G_FILE_ATTRIBUTE_TYPE_UINT64

an unsigned 8-byte/64-bit integer.

G_FILE_ATTRIBUTE_TYPE_INT64

a signed 8-byte/64-bit integer.

G_FILE_ATTRIBUTE_TYPE_OBJECT

a GObject.

enum GFileAttributeInfoFlags

typedef enum {
  G_FILE_ATTRIBUTE_INFO_NONE            = 0,
  G_FILE_ATTRIBUTE_INFO_COPY_WITH_FILE  = (1 << 0),
  G_FILE_ATTRIBUTE_INFO_COPY_WHEN_MOVED = (1 << 1)
} GFileAttributeInfoFlags;

Flags specifying the behaviour of an attribute.

G_FILE_ATTRIBUTE_INFO_NONE

no flags set.

G_FILE_ATTRIBUTE_INFO_COPY_WITH_FILE

copy the attribute values when the file is copied.

G_FILE_ATTRIBUTE_INFO_COPY_WHEN_MOVED

copy the attribute values when the file is moved.

enum GFileAttributeStatus

typedef enum {
  G_FILE_ATTRIBUTE_STATUS_UNSET = 0,
  G_FILE_ATTRIBUTE_STATUS_SET,
  G_FILE_ATTRIBUTE_STATUS_ERROR_SETTING
} GFileAttributeStatus;

Used by g_file_set_attributes_from_info() when setting file attributes.

G_FILE_ATTRIBUTE_STATUS_UNSET

Attribute value is unset (empty).

G_FILE_ATTRIBUTE_STATUS_SET

Attribute value is set.

G_FILE_ATTRIBUTE_STATUS_ERROR_SETTING

Indicates an error in setting the value.

GFileAttributeInfo

typedef struct {
  char                    *name;
  GFileAttributeType       type;
  GFileAttributeInfoFlags  flags;
} GFileAttributeInfo;

Information about a specific attribute.

char *name;

the name of the attribute.

GFileAttributeType type;

the GFileAttributeType type of the attribute.

GFileAttributeInfoFlags flags;

a set of GFileAttributeInfoFlags.

GFileAttributeInfoList

typedef struct {
  GFileAttributeInfo *infos;
  int                 n_infos;
} GFileAttributeInfoList;

Acts as a lightweight registry for possible valid file attributes. The registry stores Key-Value pair formats as GFileAttributeInfos.

GFileAttributeInfo *infos;

an array of GFileAttributeInfos.

int n_infos;

the number of values in the array.

g_file_attribute_info_list_new ()

GFileAttributeInfoList * g_file_attribute_info_list_new (void);

Creates a new file attribute info list.

Returns :

a GFileAttributeInfoList.

g_file_attribute_info_list_ref ()

GFileAttributeInfoList * g_file_attribute_info_list_ref (GFileAttributeInfoList *list);

References a file attribute info list.

list :

a GFileAttributeInfoList to reference.

Returns :

GFileAttributeInfoList or NULL on error.

g_file_attribute_info_list_unref ()

void                g_file_attribute_info_list_unref    (GFileAttributeInfoList *list);

Removes a reference from the given list. If the reference count falls to zero, the list is deleted.

list :

The GFileAttributeInfoList to unreference.

g_file_attribute_info_list_dup ()

GFileAttributeInfoList * g_file_attribute_info_list_dup (GFileAttributeInfoList *list);

Makes a duplicate of a file attribute info list.

list :

a GFileAttributeInfoList to duplicate.

Returns :

a copy of the given list.

g_file_attribute_info_list_lookup ()

const GFileAttributeInfo * g_file_attribute_info_list_lookup
                                                        (GFileAttributeInfoList *list,
                                                         const char *name);

Gets the file attribute with the name name from list.

list :

a GFileAttributeInfoList.

name :

the name of the attribute to lookup.

Returns :

a GFileAttributeInfo for the name, or NULL if an attribute isn't found.

g_file_attribute_info_list_add ()

void                g_file_attribute_info_list_add      (GFileAttributeInfoList *list,
                                                         const char *name,
                                                         GFileAttributeType type,
                                                         GFileAttributeInfoFlags flags);

Adds a new attribute with name to the list, setting its type and flags.

list :

a GFileAttributeInfoList.

name :

the name of the attribute to add.

type :

the GFileAttributeType for the attribute.

flags :

GFileAttributeInfoFlags for the attribute.

See Also

GFile, GFileInfo