Linux-Inotify2/Inotify2.pm

=head1 NAME

Linux::Inotify2 - scalable directory/file change notification

=head1 SYNOPSIS

=head2 Callback Interface

 use Linux::Inotify2;

 # create a new object
 my $inotify = new Linux::Inotify2
    or die "unable to create new inotify object: $!";
 
 # add watchers
 $inotify->watch ("/etc/passwd", IN_ACCESS, sub {
    my $e = shift;
    my $name = $e->fullname;
    print "$name was accessed\n" if $e->IN_ACCESS;
    print "$name is no longer mounted\n" if $e->IN_UNMOUNT;
    print "$name is gone\n" if $e->IN_IGNORED;
    print "events for $name have been lost\n" if $e->IN_Q_OVERFLOW;
 
    # cancel this watcher: remove no further events
    $e->w->cancel;
 });

 # integration into AnyEvent (works with POE, Glib, Tk...)
 my $inotify_w = AnyEvent->io 
    fh => $inofity, poll => 'r', cb => sub { $inotify->poll }
 );

 # manual event loop
 1 while $inotify->poll;

=head2 Streaming Interface

 use Linux::Inotify2 ;

 # create a new object
 my $inotify = new Linux::Inotify2
    or die "Unable to create new inotify object: $!" ;

 # create watch
 $inotify->watch ("/etc/passwd", IN_ACCESS)
    or die "watch creation failed" ;

 while () {
   my @events = $inotify->read;
   unless (@events > 0) {
     print "read error: $!";
     last ;
   }
   printf "mask\t%d\n", $_->mask foreach @events ; 
 }

=head1 DESCRIPTION

This module implements an interface to the Linux 2.6.13 and later Inotify
file/directory change notification sytem.

It has a number of advantages over the Linux::Inotify module:

   - it is portable (Linux::Inotify only works on x86)
   - the equivalent of fullname works correctly
   - it is better documented
   - it has callback-style interface, which is better suited for
     integration.

=head2 The Linux::Inotify2 Class

=over 4

=cut

package Linux::Inotify2;

use Carp ();
use Fcntl ();
use Scalar::Util ();

use base 'Exporter';

BEGIN {
   $VERSION = '1.2';

   @constants = qw(
      IN_ACCESS IN_MODIFY IN_ATTRIB IN_CLOSE_WRITE
      IN_CLOSE_NOWRITE IN_OPEN IN_MOVED_FROM IN_MOVED_TO
      IN_CREATE IN_DELETE IN_DELETE_SELF IN_MOVE_SELF
      IN_ALL_EVENTS
      IN_UNMOUNT IN_Q_OVERFLOW IN_IGNORED
      IN_CLOSE IN_MOVE
      IN_ISDIR IN_ONESHOT IN_MASK_ADD IN_DONT_FOLLOW IN_ONLYDIR
   );

   @EXPORT = @constants;

   require XSLoader;
   XSLoader::load Linux::Inotify2, $VERSION;
}

=item my $inotify = new Linux::Inotify2

Create a new notify object and return it. A notify object is kind of a
container that stores watches on filesystem names and is responsible for
handling event data.

On error, C<undef> is returned and C<$!> will be set accordingly. The followign errors
are documented:

 ENFILE   The system limit on the total number of file descriptors has been reached.
 EMFILE   The user limit on the total number of inotify instances has been reached.
 ENOMEM   Insufficient kernel memory is available.

Example:

   my $inotify = new Linux::Inotify2
      or die "Unable to create new inotify object: $!";

=cut

sub new {
   my ($class) = @_;

   my $fd = inotify_init;

   return unless $fd >= 0;

   bless { fd => $fd }, $class
}

=item $watch = $inotify->watch ($name, $mask[, $cb])

Add a new watcher to the given notifier. The watcher will create events
on the pathname C<$name> as given in C<$mask>, which can be any of the
following constants (all exported by default) ORed together.

"file" refers to any filesystem object in the watch'ed object (always a
directory), that is files, directories, symlinks, device nodes etc., while
"object" refers to the object the watch has been set on itself:

 IN_ACCESS            object was accessed
 IN_MODIFY            object was modified
 IN_ATTRIB            object metadata changed
 IN_CLOSE_WRITE       writable fd to file / to object was closed
 IN_CLOSE_NOWRITE     readonly fd to file / to object closed
 IN_OPEN              object was opened
 IN_MOVED_FROM        file was moved from this object (directory)
 IN_MOVED_TO          file was moved to this object (directory)
 IN_CREATE            file was created in this object (directory)
 IN_DELETE            file was deleted from this object (directory)
 IN_DELETE_SELF       object itself was deleted
 IN_MOVE_SELF         object itself was moved
 IN_ALL_EVENTS        all of the above events

 IN_ONESHOT           only send event once
 IN_ONLYDIR           only watch the path if it is a directory
 IN_DONT_FOLLOW       don't follow a sym link
 IN_MASK_ADD          not supported with the current version of this module

 IN_CLOSE             same as IN_CLOSE_WRITE | IN_CLOSE_NOWRITE
 IN_MOVE              same as IN_MOVED_FROM | IN_MOVED_TO

C<$cb> is a perl code reference that, if given, is called for each
event. It receives a C<Linux::Inotify2::Event> object.

The returned C<$watch> object is of class C<Linux::Inotify2::Watch>.

On error, C<undef> is returned and C<$!> will be set accordingly. The
following errors are documented:

 EBADF    The given file descriptor is not valid.
 EINVAL   The given event mask contains no legal events.
 ENOMEM   Insufficient kernel memory was available.
 ENOSPC   The user limit on the total number of inotify watches was reached or the kernel failed to allocate a needed resource.
 EACCESS  Read access to the given file is not permitted.

Example, show when C</etc/passwd> gets accessed and/or modified once:

   $inotify->watch ("/etc/passwd", IN_ACCESS | IN_MODIFY, sub {
      my $e = shift;
      print "$e->{w}{name} was accessed\n" if $e->IN_ACCESS;
      print "$e->{w}{name} was modified\n" if $e->IN_MODIFY;
      print "$e->{w}{name} is no longer mounted\n" if $e->IN_UNMOUNT;
      print "events for $e->{w}{name} have been lost\n" if $e->IN_Q_OVERFLOW;

      $e->w->cancel;
   });

=cut

sub watch {
   my ($self, $name, $mask, $cb) = @_;

   my $wd = inotify_add_watch $self->{fd}, $name, $mask;

   return unless $wd >= 0;
   
   my $w = $self->{w}{$wd} = bless {
      inotify => $self,
      wd      => $wd,
      name    => $name,
      mask    => $mask,
      cb      => $cb,
   }, "Linux::Inotify2::Watch";

   Scalar::Util::weaken $w->{inotify};

   $w
}

=item $inotify->fileno

Returns the fileno for this notify object. You are responsible for calling
the C<poll> method when this fileno becomes ready for reading.

=cut

sub fileno {
   $_[0]{fd}
}

=item $inotify->blocking ($blocking)

Clears ($blocking true) or sets ($blocking false) the C<O_NONBLOCK> flag on the file descriptor.

=cut

sub blocking {
   my ($self, $blocking) = @_;

   inotify_blocking $self->{fd}, $blocking;
}

=item $count = $inotify->poll

Reads events from the kernel and handles them. If the notify fileno is
blocking (the default), then this method waits for at least one event
(and thus returns true unless an error occurs). Otherwise it returns
immediately when no pending events could be read.

Returns the count of events that have been handled.

=cut

sub poll {
   scalar &read
}

=item $count = $inotify->read

Reads events from the kernel. Blocks in blocking mode (default) until any
event arrives. Returns list of C<Linux::Inotify2::Event> objects or empty
list if none (non-blocking mode) or error occured ($! should be checked).

=cut

sub read {
   my ($self) = @_;

   my @ev = inotify_read $self->{fd};
   my @res;

   for (@ev) {
      my $w = $_->{w} = $self->{w}{$_->{wd}}
         or next; # no such watcher

      exists $self->{ignore}{$_->{wd}}
         and next; # watcher has been canceled

      bless $_, "Linux::Inotify2::Event";

      push @res, $_;

      $w->{cb}->($_) if $w->{cb};
      $w->cancel if $_->{mask} & (IN_IGNORED | IN_UNMOUNT | IN_ONESHOT | IN_DELETE_SELF);
   }

   delete $self->{ignore};

   @res
}

sub DESTROY {
   inotify_close $_[0]{fd}
}

=back

=head2 The Linux::Inotify2::Event Class

Objects of this class are handed as first argument to the watch
callback. It has the following members and methods:

=over 4

=item $event->w

=item $event->{w}

The watcher object for this event.

=item $event->name

=item $event->{name}

The path of the filesystem object, relative to the watch name.

=item $watch->fullname

Returns the "full" name of the relevant object, i.e. including the C<name>
member of the watcher (if the the watch is on a directory and a dir entry
is affected), or simply the C<name> member itself when the object is the
watch object itself.

=item $event->mask

=item $event->{mask}

The received event mask. In addition the the events described for
C<$inotify->watch>, the following flags (exported by default) can be set:

 IN_ISDIR             event object is a directory
 IN_Q_OVERFLOW        event queue overflowed

 # when any of the following flags are set,
 # then watchers for this event are automatically canceled
 IN_UNMOUNT           filesystem for watch'ed object was unmounted
 IN_IGNORED           file was ignored/is gone (no more events are delivered)
 IN_ONESHOT           only one event was generated

=item $event->IN_xxx

Returns a boolean that returns true if the event mask matches the
event. All of the C<IN_xxx> constants can be used as methods.

=item $event->cookie

=item $event->{cookie}

The event cookie to "synchronize two events". Normally zero, this value is
set when two events relating to the same file are generated. As far as I
know, this only happens for C<IN_MOVED_FROM> and C<IN_MOVED_TO> events, to
identify the old and new name of a file.

=back

=cut

package Linux::Inotify2::Event;

sub w       { $_[0]{w}      }
sub name    { $_[0]{name}   }
sub mask    { $_[0]{mask}   }
sub cookie  { $_[0]{cookie} }

sub fullname {
   length $_[0]{name}
      ? "$_[0]{w}{name}/$_[0]{name}"
      : $_[0]{w}{name};
}

for my $name (@Linux::Inotify2::constants) {
   my $mask = &{"Linux::Inotify2::$name"};

   *$name = sub { ($_[0]{mask} & $mask) == $mask };
}

=head2 The Linux::Inotify2::Watch Class

Watch objects are created by calling the C<watch> method of a notifier.

It has the following members and methods:

=over 4

=item $watch->name

=item $watch->{name}

The name as specified in the C<watch> call. For the object itself, this is
the empty string.  For directory watches, this is the name of the entry
without leading path elements.

=item $watch->mask

=item $watch->{mask}

The mask as specified in the C<watch> call.

=item $watch->cb ([new callback])

=item $watch->{cb}

The callback as specified in the C<watch> call. Can optionally be changed.

=item $watch->cancel

Cancels/removes this watch. Future events, even if already queued queued,
will not be handled and resources will be freed.

=back

=cut

package Linux::Inotify2::Watch;

sub name    { $_[0]{name} }
sub mask    { $_[0]{mask} }

sub cb {
   $_[0]{cb} = $_[1] if @_ > 1;
   $_[0]{cb}
}

sub cancel {
   my ($self) = @_;

   my $inotify = delete $self->{inotify}
      or return 1; # already canceled

   delete $inotify->{w}{$self->{wd}}; # we are no longer there
   $inotify->{ignore}{$self->{wd}} = 1; # ignore further events for one poll

   (Linux::Inotify2::inotify_rm_watch $inotify->{fd}, $self->{wd})
      ? 1 : undef
}

=head1 SEE ALSO

L<AnyEvent>, L<Linux::Inotify>.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

1
Revision:	1.19
Committed:	Tue Oct 7 17:25:11 2008 UTC (17 years, 11 months ago) by root
Branch:	MAIN
CVS Tags:	rel-1_2
Changes since 1.18:	+4 -4 lines
Log Message:	1.2
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Linux::Inotify2 - scalable directory/file change notification
4
5			=head1 SYNOPSIS
6
7	root	1.19	=head2 Callback Interface
8	root	1.11
9	root	1.1	use Linux::Inotify2;
10
11	root	1.4	# create a new object
12			my $inotify = new Linux::Inotify2
13	root	1.19	or die "unable to create new inotify object: $!";
14	root	1.4
15			# add watchers
16			$inotify->watch ("/etc/passwd", IN_ACCESS, sub {
17			my $e = shift;
18			my $name = $e->fullname;
19			print "$name was accessed\n" if $e->IN_ACCESS;
20			print "$name is no longer mounted\n" if $e->IN_UNMOUNT;
21			print "$name is gone\n" if $e->IN_IGNORED;
22			print "events for $name have been lost\n" if $e->IN_Q_OVERFLOW;
23
24	root	1.11	# cancel this watcher: remove no further events
25	root	1.4	$e->w->cancel;
26			});
27
28	root	1.18	# integration into AnyEvent (works with POE, Glib, Tk...)
29	root	1.17	my $inotify_w = AnyEvent->io
30			fh => $inofity, poll => 'r', cb => sub { $inotify->poll }
31			);
32
33			# manual event loop
34			1 while $inotify->poll;
35
36	root	1.11	=head2 Streaming Interface
37
38			use Linux::Inotify2 ;
39
40			# create a new object
41			my $inotify = new Linux::Inotify2
42			or die "Unable to create new inotify object: $!" ;
43
44			# create watch
45			$inotify->watch ("/etc/passwd", IN_ACCESS)
46			or die "watch creation failed" ;
47
48			while () {
49			my @events = $inotify->read;
50			unless (@events > 0) {
51			print "read error: $!";
52			last ;
53			}
54			printf "mask\t%d\n", $_->mask foreach @events ;
55			}
56
57	root	1.1	=head1 DESCRIPTION
58
59	root	1.3	This module implements an interface to the Linux 2.6.13 and later Inotify
60			file/directory change notification sytem.
61	root	1.2
62	root	1.3	It has a number of advantages over the Linux::Inotify module:
63	root	1.2
64			- it is portable (Linux::Inotify only works on x86)
65			- the equivalent of fullname works correctly
66			- it is better documented
67			- it has callback-style interface, which is better suited for
68			integration.
69
70	root	1.6	=head2 The Linux::Inotify2 Class
71
72	root	1.1	=over 4
73
74			=cut
75
76			package Linux::Inotify2;
77
78			use Carp ();
79	root	1.11	use Fcntl ();
80	root	1.1	use Scalar::Util ();
81
82			use base 'Exporter';
83
84			BEGIN {
85	root	1.19	$VERSION = '1.2';
86	root	1.1
87			@constants = qw(
88			IN_ACCESS IN_MODIFY IN_ATTRIB IN_CLOSE_WRITE
89			IN_CLOSE_NOWRITE IN_OPEN IN_MOVED_FROM IN_MOVED_TO
90	root	1.9	IN_CREATE IN_DELETE IN_DELETE_SELF IN_MOVE_SELF
91	root	1.1	IN_ALL_EVENTS
92			IN_UNMOUNT IN_Q_OVERFLOW IN_IGNORED
93			IN_CLOSE IN_MOVE
94	root	1.15	IN_ISDIR IN_ONESHOT IN_MASK_ADD IN_DONT_FOLLOW IN_ONLYDIR
95	root	1.1	);
96
97			@EXPORT = @constants;
98
99			require XSLoader;
100			XSLoader::load Linux::Inotify2, $VERSION;
101			}
102
103			=item my $inotify = new Linux::Inotify2
104
105			Create a new notify object and return it. A notify object is kind of a
106			container that stores watches on filesystem names and is responsible for
107			handling event data.
108
109			On error, C<undef> is returned and C<$!> will be set accordingly. The followign errors
110			are documented:
111
112			ENFILE The system limit on the total number of file descriptors has been reached.
113			EMFILE The user limit on the total number of inotify instances has been reached.
114			ENOMEM Insufficient kernel memory is available.
115
116	root	1.4	Example:
117
118			my $inotify = new Linux::Inotify2
119			or die "Unable to create new inotify object: $!";
120
121	root	1.1	=cut
122
123			sub new {
124			my ($class) = @_;
125
126			my $fd = inotify_init;
127
128			return unless $fd >= 0;
129
130			bless { fd => $fd }, $class
131			}
132
133	root	1.11	=item $watch = $inotify->watch ($name, $mask[, $cb])
134	root	1.1
135			Add a new watcher to the given notifier. The watcher will create events
136			on the pathname C<$name> as given in C<$mask>, which can be any of the
137	root	1.4	following constants (all exported by default) ORed together.
138
139			"file" refers to any filesystem object in the watch'ed object (always a
140			directory), that is files, directories, symlinks, device nodes etc., while
141			"object" refers to the object the watch has been set on itself:
142
143			IN_ACCESS object was accessed
144			IN_MODIFY object was modified
145			IN_ATTRIB object metadata changed
146			IN_CLOSE_WRITE writable fd to file / to object was closed
147			IN_CLOSE_NOWRITE readonly fd to file / to object closed
148			IN_OPEN object was opened
149			IN_MOVED_FROM file was moved from this object (directory)
150			IN_MOVED_TO file was moved to this object (directory)
151			IN_CREATE file was created in this object (directory)
152			IN_DELETE file was deleted from this object (directory)
153			IN_DELETE_SELF object itself was deleted
154	root	1.9	IN_MOVE_SELF object itself was moved
155	root	1.4	IN_ALL_EVENTS all of the above events
156	root	1.1
157			IN_ONESHOT only send event once
158	root	1.15	IN_ONLYDIR only watch the path if it is a directory
159			IN_DONT_FOLLOW don't follow a sym link
160			IN_MASK_ADD not supported with the current version of this module
161	root	1.1
162	root	1.4	IN_CLOSE same as IN_CLOSE_WRITE \| IN_CLOSE_NOWRITE
163			IN_MOVE same as IN_MOVED_FROM \| IN_MOVED_TO
164	root	1.1
165	root	1.11	C<$cb> is a perl code reference that, if given, is called for each
166			event. It receives a C<Linux::Inotify2::Event> object.
167	root	1.1
168			The returned C<$watch> object is of class C<Linux::Inotify2::Watch>.
169
170			On error, C<undef> is returned and C<$!> will be set accordingly. The
171			following errors are documented:
172
173			EBADF The given file descriptor is not valid.
174			EINVAL The given event mask contains no legal events.
175			ENOMEM Insufficient kernel memory was available.
176			ENOSPC The user limit on the total number of inotify watches was reached or the kernel failed to allocate a needed resource.
177			EACCESS Read access to the given file is not permitted.
178
179			Example, show when C</etc/passwd> gets accessed and/or modified once:
180
181			$inotify->watch ("/etc/passwd", IN_ACCESS \| IN_MODIFY, sub {
182			my $e = shift;
183			print "$e->{w}{name} was accessed\n" if $e->IN_ACCESS;
184			print "$e->{w}{name} was modified\n" if $e->IN_MODIFY;
185			print "$e->{w}{name} is no longer mounted\n" if $e->IN_UNMOUNT;
186			print "events for $e->{w}{name} have been lost\n" if $e->IN_Q_OVERFLOW;
187
188			$e->w->cancel;
189			});
190
191			=cut
192
193			sub watch {
194			my ($self, $name, $mask, $cb) = @_;
195
196			my $wd = inotify_add_watch $self->{fd}, $name, $mask;
197
198			return unless $wd >= 0;
199
200			my $w = $self->{w}{$wd} = bless {
201			inotify => $self,
202			wd => $wd,
203			name => $name,
204			mask => $mask,
205			cb => $cb,
206	root	1.13	}, "Linux::Inotify2::Watch";
207	root	1.1
208			Scalar::Util::weaken $w->{inotify};
209
210			$w
211			}
212
213	root	1.4	=item $inotify->fileno
214	root	1.1
215			Returns the fileno for this notify object. You are responsible for calling
216			the C<poll> method when this fileno becomes ready for reading.
217
218			=cut
219
220			sub fileno {
221			$_[0]{fd}
222			}
223
224	root	1.11	=item $inotify->blocking ($blocking)
225
226			Clears ($blocking true) or sets ($blocking false) the C<O_NONBLOCK> flag on the file descriptor.
227
228			=cut
229
230			sub blocking {
231			my ($self, $blocking) = @_;
232
233			inotify_blocking $self->{fd}, $blocking;
234			}
235
236	root	1.4	=item $count = $inotify->poll
237	root	1.1
238	root	1.4	Reads events from the kernel and handles them. If the notify fileno is
239			blocking (the default), then this method waits for at least one event
240			(and thus returns true unless an error occurs). Otherwise it returns
241			immediately when no pending events could be read.
242	root	1.1
243			Returns the count of events that have been handled.
244
245			=cut
246
247			sub poll {
248	root	1.11	scalar &read
249			}
250
251			=item $count = $inotify->read
252
253			Reads events from the kernel. Blocks in blocking mode (default) until any
254			event arrives. Returns list of C<Linux::Inotify2::Event> objects or empty
255			list if none (non-blocking mode) or error occured ($! should be checked).
256
257			=cut
258
259			sub read {
260	root	1.1	my ($self) = @_;
261
262	root	1.4	my @ev = inotify_read $self->{fd};
263	root	1.11	my @res;
264	root	1.4
265			for (@ev) {
266			my $w = $_->{w} = $self->{w}{$_->{wd}}
267	root	1.1	or next; # no such watcher
268	root	1.4
269			exists $self->{ignore}{$_->{wd}}
270			and next; # watcher has been canceled
271
272	root	1.13	bless $_, "Linux::Inotify2::Event";
273	root	1.12
274	root	1.11	push @res, $_;
275
276	root	1.12	$w->{cb}->($_) if $w->{cb};
277	root	1.16	$w->cancel if $_->{mask} & (IN_IGNORED \| IN_UNMOUNT \| IN_ONESHOT \| IN_DELETE_SELF);
278	root	1.1	}
279	root	1.4
280			delete $self->{ignore};
281
282	root	1.11	@res
283	root	1.1	}
284
285			sub DESTROY {
286			inotify_close $_[0]{fd}
287			}
288
289			=back
290
291			=head2 The Linux::Inotify2::Event Class
292
293			Objects of this class are handed as first argument to the watch
294			callback. It has the following members and methods:
295
296			=over 4
297
298			=item $event->w
299
300			=item $event->{w}
301
302			The watcher object for this event.
303
304			=item $event->name
305
306			=item $event->{name}
307
308			The path of the filesystem object, relative to the watch name.
309
310			=item $watch->fullname
311
312			Returns the "full" name of the relevant object, i.e. including the C<name>
313	root	1.7	member of the watcher (if the the watch is on a directory and a dir entry
314			is affected), or simply the C<name> member itself when the object is the
315			watch object itself.
316	root	1.1
317			=item $event->mask
318
319			=item $event->{mask}
320
321			The received event mask. In addition the the events described for
322			C<$inotify->watch>, the following flags (exported by default) can be set:
323
324	root	1.4	IN_ISDIR event object is a directory
325			IN_Q_OVERFLOW event queue overflowed
326
327	root	1.10	# when any of the following flags are set,
328			# then watchers for this event are automatically canceled
329	root	1.4	IN_UNMOUNT filesystem for watch'ed object was unmounted
330			IN_IGNORED file was ignored/is gone (no more events are delivered)
331	root	1.10	IN_ONESHOT only one event was generated
332	root	1.1
333			=item $event->IN_xxx
334
335			Returns a boolean that returns true if the event mask matches the
336			event. All of the C<IN_xxx> constants can be used as methods.
337
338			=item $event->cookie
339
340			=item $event->{cookie}
341
342	root	1.10	The event cookie to "synchronize two events". Normally zero, this value is
343			set when two events relating to the same file are generated. As far as I
344			know, this only happens for C<IN_MOVED_FROM> and C<IN_MOVED_TO> events, to
345			identify the old and new name of a file.
346	root	1.1
347			=back
348
349			=cut
350
351			package Linux::Inotify2::Event;
352
353			sub w { $_[0]{w} }
354			sub name { $_[0]{name} }
355			sub mask { $_[0]{mask} }
356			sub cookie { $_[0]{cookie} }
357
358			sub fullname {
359			length $_[0]{name}
360			? "$_[0]{w}{name}/$_[0]{name}"
361			: $_[0]{w}{name};
362			}
363
364			for my $name (@Linux::Inotify2::constants) {
365			my $mask = &{"Linux::Inotify2::$name"};
366
367			*$name = sub { ($_[0]{mask} & $mask) == $mask };
368			}
369
370			=head2 The Linux::Inotify2::Watch Class
371
372			Watch objects are created by calling the C<watch> method of a notifier.
373
374			It has the following members and methods:
375
376	root	1.14	=over 4
377
378	root	1.1	=item $watch->name
379
380			=item $watch->{name}
381
382			The name as specified in the C<watch> call. For the object itself, this is
383			the empty string. For directory watches, this is the name of the entry
384			without leading path elements.
385
386			=item $watch->mask
387
388			=item $watch->{mask}
389
390			The mask as specified in the C<watch> call.
391
392			=item $watch->cb ([new callback])
393
394			=item $watch->{cb}
395
396			The callback as specified in the C<watch> call. Can optionally be changed.
397
398			=item $watch->cancel
399
400			Cancels/removes this watch. Future events, even if already queued queued,
401			will not be handled and resources will be freed.
402
403	root	1.14	=back
404
405	root	1.1	=cut
406
407			package Linux::Inotify2::Watch;
408
409			sub name { $_[0]{name} }
410			sub mask { $_[0]{mask} }
411
412			sub cb {
413			$_[0]{cb} = $_[1] if @_ > 1;
414			$_[0]{cb}
415			}
416
417			sub cancel {
418			my ($self) = @_;
419
420	root	1.4	my $inotify = delete $self->{inotify}
421			or return 1; # already canceled
422
423			delete $inotify->{w}{$self->{wd}}; # we are no longer there
424			$inotify->{ignore}{$self->{wd}} = 1; # ignore further events for one poll
425
426			(Linux::Inotify2::inotify_rm_watch $inotify->{fd}, $self->{wd})
427	root	1.1	? 1 : undef
428			}
429
430			=head1 SEE ALSO
431
432	root	1.19	L<AnyEvent>, L<Linux::Inotify>.
433	root	1.1
434			=head1 AUTHOR
435
436			Marc Lehmann <schmorp@schmorp.de>
437			http://home.schmorp.de/
438
439			=cut
440
441			1