definition module Inotify

/**
 * Links with Linux's inotify
 */

from Data.Either import ::Either
from Data.Maybe import ::Maybe

/**
 * An inotify file descriptor
 *
 * @var A state that is used for callbacks
 */
:: *Inotify st

//* An inotify watch descriptor
:: INWatch

//* An inotify event mask
:: INMask :== Int

//* An inotify event
:: INEvent :== Int

/**
 * An inotify callback: event, maybe filename, state, world -> state, world
 *
 * @var A state that is passed on.
 */
:: INCallback st :== INEvent (Maybe String) st *World -> *(st, *World)

//* Bitwise OR for event masks
(|-) infixl 6 :: (INMask INMask -> INMask)

/**
 * Initialise an inotify file descriptor with some state.
 *
 * @param The initial state
 * @result A file descriptor or Nothing if the C initialisation failed
 */
inotify_init :: st -> Maybe *(Inotify st)

/**
 * Close an inotify file descriptor and get back the state
 *
 * @param The file descriptor
 * @result The final state
 */
inotify_close :: *(Inotify st) -> st

/**
 * Add a watch on some file
 *
 * @param The callback for events
 * @param A mask of events to watch for
 * @param The filename
 * @param The inotify file descriptor
 * @result Either an error code or a watch descriptor, and the inotify file descriptor
 */
inotify_add_watch :: (INCallback st) !INMask !String !*(Inotify st)
	-> *(!Either Int INWatch, !*Inotify st)

/**
 * Remove a watch
 *
 * @param The watch to remove
 * @param The inotify file descriptor
 * @result A boolean indicating success and the inotify file descriptor
 */
inotify_rm_watch :: !INWatch !*(Inotify st) -> *(!Bool, !*Inotify st)

/**
 * Poll an inotify file descriptor; i.e. wait for new events
 *
 * @param Timeout in milliseconds (Nothing for no timeout)
 * @param The inotify file descriptor
 * @result The number of events, and the inotify file descriptor
 */
inotify_poll :: !(Maybe Int) !*(Inotify st) -> *(!Int, !*Inotify st)

/**
 * Check for new events and call callbacks
 */
inotify_check :: !*(Inotify st) !*World -> *(!*Inotify st, !*World)

/**
 * Check if an event matches a mask
 *
 * @param The mask
 * @param The event
 * @result True iff the event matches the mask
 */
inotify_is_event :: INMask INEvent -> Bool

/**
 * Combination of inotify_poll and inotify_check that will return only if no
 * events were given when a timeout occurred.
 *
 * @param Timeout in milliseconds (Nothing for no timeout)
 * @param The inotify file descriptor
 * @param The World
 * @result The inotify file descriptor and the World. However, the function
 *   only returns if no events were given when the timeout occurred. Otherwise,
 *   it will loop.
 */
inotify_loop_with_timeout :: !(Maybe Int) !*(Inotify st) !*World
	-> *(!*Inotify st, !*World)

/**
 * inotify_loop_with_timeout with Nothing as timeout (will never return)
 *
 * @param The inotify file descriptor
 * @param The World
 * @result The parameters back, however, this function will never return.
 */
inotify_loop_forever :: !*(Inotify st) !*World -> *(!*Inotify st, !*World)

/*** Begin inotify.h ***/

//* Inotify event mask: file was accessed
IN_ACCESS        :== 0x00000001
//* Inotify event mask: file was modified
IN_MODIFY        :== 0x00000002
//* Inotify event mask: metadata changed
IN_ATTRIB        :== 0x00000004
//* Inotify event mask: file opened for writing was closed
IN_CLOSE_WRITE   :== 0x00000008
//* Inotify event mask: file not opened for writing was closed
IN_CLOSE_NOWRITE :== 0x00000010
//* Inotify event mask: file was opened
IN_OPEN          :== 0x00000020
//* Inotify event mask: file was moved from watched directory
IN_MOVED_FROM    :== 0x00000040
//* Inotify event mask: file was moved to watched directory
IN_MOVED_TO      :== 0x00000080
//* Inotify event mask: file was created in watched directory
IN_CREATE        :== 0x00000100
//* Inotify event mask: file in watched directory was deleted
IN_DELETE        :== 0x00000200
//* Inotify event mask: watched file was deleted
IN_DELETE_SELF   :== 0x00000400
//* Inotify event mask: watched file was moved
IN_MOVE_SELF     :== 0x00000800
//* Inotify event mask: backing fs of watched file was unmounted
IN_UNMOUNT       :== 0x00002000
//* Inotify event mask: the inotify event queue overflowed
IN_Q_OVERFLOW    :== 0x00004000
/**
 * Inotify event mask: the watch has been removed, either through
 * inotify_rm_watch or because it was deleted, the fs was unmounted, etc.
 */
IN_IGNORED       :== 0x00008000
/**
 * Inotify event mask: watched file was closed
 * @type Int
 */
IN_CLOSE         :== (IN_CLOSE_WRITE |- IN_CLOSE_NOWRITE)
/**
 * Inotify event mask: a file was moved from or to a watched directory
 * @type Int
 */
IN_MOVE          :== (IN_MOVED_FROM |- IN_MOVED_TO)
//* Inotify event mask: only watch the path if it is a directory
IN_ONLYDIR       :== 0x01000000
//* Inotify event mask: don't follow symlinks
IN_DONT_FOLLOW   :== 0x02000000
//* Inotify event mask: stop watching files when they get unlinked
IN_EXCL_UNLINK   :== 0x04000000
/**
 * Inotify event mask: when adding a watch on a path for which a watch already
 * exists, OR the new event mask with the old one instead of replacing it.
 */
IN_MASK_ADD      :== 0x20000000
//* Inotify event mask: the event occurred against a directory
IN_ISDIR         :== 0x40000000
//* Inotify event mask: monitor a watch only for one event, then remove it
IN_ONESHOT       :== 0x80000000
/**
 * Inotify event mask: OR of all events
 * @type Int
 */
IN_ALL_EVENTS    :==
	(IN_ACCESS |- IN_MODIFY |- IN_ATTRIB |- IN_CLOSE_WRITE |- IN_CLOSE_NOWRITE
	|- IN_OPEN |- IN_MOVED_FROM |- IN_MOVED_TO |- IN_DELETE |- IN_CREATE |-
	IN_DELETE_SELF |- IN_MOVE_SELF)

/*** End inotify.h ***/