[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs.
Revision 1.169 by root, Sat Jan 2 13:02:20 2010 UTC

…		…
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
		31	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		32	use AnyEvent::AIO;
		33
30	# AnyEvent integration	34	# EV integration
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";	35	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33		36
34	# Event integration	37	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,	38	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',	39	poll => 'r',
37	cb => \&IO::AIO::poll_cb);	40	cb => \&IO::AIO::poll_cb);
…		…
49	\&IO::AIO::poll_cb);	52	\&IO::AIO::poll_cb);
50		53
51	=head1 DESCRIPTION	54	=head1 DESCRIPTION
52		55
53	This module implements asynchronous I/O using whatever means your	56	This module implements asynchronous I/O using whatever means your
54	operating system supports.	57	operating system supports. It is implemented as an interface to C<libeio>
		58	(L<http://software.schmorp.de/pkg/libeio.html>).
55		59
56	Asynchronous means that operations that can normally block your program	60	Asynchronous means that operations that can normally block your program
57	(e.g. reading from disk) will be done asynchronously: the operation	61	(e.g. reading from disk) will be done asynchronously: the operation
58	will still block, but you can do something else in the meantime. This	62	will still block, but you can do something else in the meantime. This
59	is extremely useful for programs that need to stay interactive even	63	is extremely useful for programs that need to stay interactive even
…		…
61	etc.), but can also be used to easily do operations in parallel that are	65	etc.), but can also be used to easily do operations in parallel that are
62	normally done sequentially, e.g. stat'ing many files, which is much faster	66	normally done sequentially, e.g. stat'ing many files, which is much faster
63	on a RAID volume or over NFS when you do a number of stat operations	67	on a RAID volume or over NFS when you do a number of stat operations
64	concurrently.	68	concurrently.
65		69
66	While this works on all types of file descriptors (for example sockets),	70	While most of this works on all types of file descriptors (for
67	using these functions on file descriptors that support nonblocking	71	example sockets), using these functions on file descriptors that
68	operation (again, sockets, pipes etc.) is very inefficient. Use an event	72	support nonblocking operation (again, sockets, pipes etc.) is
69	loop for that (such as the L<Event\|Event> module): IO::AIO will naturally	73	very inefficient. Use an event loop for that (such as the L<EV>
70	fit into such an event loop itself.	74	module): IO::AIO will naturally fit into such an event loop itself.
71		75
72	In this version, a number of threads are started that execute your	76	In this version, a number of threads are started that execute your
73	requests and signal their completion. You don't need thread support	77	requests and signal their completion. You don't need thread support
74	in perl, and the threads created by this module will not be visible	78	in perl, and the threads created by this module will not be visible
75	to perl. In the future, this module might make use of the native aio	79	to perl. In the future, this module might make use of the native aio
…		…
77	not well-supported or restricted (GNU/Linux doesn't allow them on normal	81	not well-supported or restricted (GNU/Linux doesn't allow them on normal
78	files currently, for example), and they would only support aio_read and	82	files currently, for example), and they would only support aio_read and
79	aio_write, so the remaining functionality would have to be implemented	83	aio_write, so the remaining functionality would have to be implemented
80	using threads anyway.	84	using threads anyway.
81		85
82	Although the module will work with in the presence of other (Perl-)	86	Although the module will work in the presence of other (Perl-) threads,
83	threads, it is currently not reentrant in any way, so use appropriate	87	it is currently not reentrant in any way, so use appropriate locking
84	locking yourself, always call C<poll_cb> from within the same thread, or	88	yourself, always call C<poll_cb> from within the same thread, or never
85	never call C<poll_cb> (or other C<aio_> functions) recursively.	89	call C<poll_cb> (or other C<aio_> functions) recursively.
86		90
87	=head2 EXAMPLE	91	=head2 EXAMPLE
88		92
89	This is a simple example that uses the Event module and loads	93	This is a simple example that uses the EV module and loads
90	F</etc/passwd> asynchronously:	94	F</etc/passwd> asynchronously:
91		95
92	use Fcntl;	96	use Fcntl;
93	use Event;	97	use EV;
94	use IO::AIO;	98	use IO::AIO;
95		99
96	# register the IO::AIO callback with Event	100	# register the IO::AIO callback with EV
97	Event->io (fd => IO::AIO::poll_fileno,	101	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
98	poll => 'r',
99	cb => \&IO::AIO::poll_cb);
100		102
101	# queue the request to open /etc/passwd	103	# queue the request to open /etc/passwd
102	aio_open "/etc/passwd", O_RDONLY, 0, sub {	104	aio_open "/etc/passwd", O_RDONLY, 0, sub {
103	my $fh = $_[0]	105	my $fh = shift
104	or die "error while opening: $!";	106	or die "error while opening: $!";
105		107
106	# stat'ing filehandles is generally non-blocking	108	# stat'ing filehandles is generally non-blocking
107	my $size = -s $fh;	109	my $size = -s $fh;
108		110
…		…
116		118
117	# file contents now in $contents	119	# file contents now in $contents
118	print $contents;	120	print $contents;
119		121
120	# exit event loop and program	122	# exit event loop and program
121	Event::unloop;	123	EV::unloop;
122	};	124	};
123	};	125	};
124		126
125	# possibly queue up other requests, or open GUI windows,	127	# possibly queue up other requests, or open GUI windows,
126	# check for sockets etc. etc.	128	# check for sockets etc. etc.
127		129
128	# process events as long as there are some:	130	# process events as long as there are some:
129	Event::loop;	131	EV::loop;
130		132
131	=head1 REQUEST ANATOMY AND LIFETIME	133	=head1 REQUEST ANATOMY AND LIFETIME
132		134
133	Every C<aio_*> function creates a request. which is a C data structure not	135	Every C<aio_*> function creates a request. which is a C data structure not
134	directly visible to Perl.	136	directly visible to Perl.
…		…
176	Request has reached the end of its lifetime and holds no resources anymore	178	Request has reached the end of its lifetime and holds no resources anymore
177	(except possibly for the Perl object, but its connection to the actual	179	(except possibly for the Perl object, but its connection to the actual
178	aio request is severed and calling its methods will either do nothing or	180	aio request is severed and calling its methods will either do nothing or
179	result in a runtime error).	181	result in a runtime error).
180		182
		183	=back
		184
181	=cut	185	=cut
182		186
183	package IO::AIO;	187	package IO::AIO;
184		188
185	no warnings;	189	use Carp ();
186	use strict 'vars';	190
		191	use common::sense;
187		192
188	use base 'Exporter';	193	use base 'Exporter';
189		194
190	BEGIN {	195	BEGIN {
191	our $VERSION = '2.1';	196	our $VERSION = '3.31';
192		197
193	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	198	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
194	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	199	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
195	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	200	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
196	aio_copy aio_group aio_nop aio_mknod);	201	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		202	aio_rename aio_link aio_move aio_copy aio_group
		203	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		204	aio_chmod aio_utime aio_truncate);
		205
197	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	206	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
198	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	207	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
199	min_parallel max_parallel max_idle	208	min_parallel max_parallel max_idle
200	nreqs nready npending nthreads	209	nreqs nready npending nthreads
201	max_poll_time max_poll_reqs);	210	max_poll_time max_poll_reqs
		211	sendfile fadvise);
		212
		213	push @AIO_REQ, qw(aio_busy); # not exported
202		214
203	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	215	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
204		216
205	require XSLoader;	217	require XSLoader;
206	XSLoader::load ("IO::AIO", $VERSION);	218	XSLoader::load ("IO::AIO", $VERSION);
207	}	219	}
208		220
209	=head1 FUNCTIONS	221	=head1 FUNCTIONS
210		222
211	=head2 AIO FUNCTIONS	223	=head2 AIO REQUEST FUNCTIONS
212		224
213	All the C<aio_*> calls are more or less thin wrappers around the syscall	225	All the C<aio_*> calls are more or less thin wrappers around the syscall
214	with the same name (sans C<aio_>). The arguments are similar or identical,	226	with the same name (sans C<aio_>). The arguments are similar or identical,
215	and they all accept an additional (and optional) C<$callback> argument	227	and they all accept an additional (and optional) C<$callback> argument
216	which must be a code reference. This code reference will get called with	228	which must be a code reference. This code reference will get called with
217	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	229	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
218	perl, which usually delivers "false") as it's sole argument when the given	230	perl, which usually delivers "false") as its sole argument after the given
219	syscall has been executed asynchronously.	231	syscall has been executed asynchronously.
220		232
221	All functions expecting a filehandle keep a copy of the filehandle	233	All functions expecting a filehandle keep a copy of the filehandle
222	internally until the request has finished.	234	internally until the request has finished.
223		235
224	All requests return objects of type L<IO::AIO::REQ> that allow further	236	All functions return request objects of type L<IO::AIO::REQ> that allow
225	manipulation of those requests while they are in-flight.	237	further manipulation of those requests while they are in-flight.
226		238
227	The pathnames you pass to these routines I<must> be absolute and	239	The pathnames you pass to these routines I<must> be absolute and
228	encoded in byte form. The reason for the former is that at the time the	240	encoded as octets. The reason for the former is that at the time the
229	request is being executed, the current working directory could have	241	request is being executed, the current working directory could have
230	changed. Alternatively, you can make sure that you never change the	242	changed. Alternatively, you can make sure that you never change the
231	current working directory.	243	current working directory anywhere in the program and then use relative
		244	paths.
232		245
233	To encode pathnames to byte form, either make sure you either: a)	246	To encode pathnames as octets, either make sure you either: a) always pass
234	always pass in filenames you got from outside (command line, readdir	247	in filenames you got from outside (command line, readdir etc.) without
235	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	248	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
236	your pathnames to the locale (or other) encoding in effect in the user	249	your pathnames to the locale (or other) encoding in effect in the user
237	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	250	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
238	use something else.	251	use something else to ensure your scalar has the correct contents.
		252
		253	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		254	handles correctly whether it is set or not.
239		255
240	=over 4	256	=over 4
241		257
242	=item $prev_pri = aioreq_pri [$pri]	258	=item $prev_pri = aioreq_pri [$pri]
243		259
…		…
263	aio_read $_[0], ..., sub {	279	aio_read $_[0], ..., sub {
264	...	280	...
265	};	281	};
266	};	282	};
267		283
		284
268	=item aioreq_nice $pri_adjust	285	=item aioreq_nice $pri_adjust
269		286
270	Similar to C<aioreq_pri>, but subtracts the given value from the current	287	Similar to C<aioreq_pri>, but subtracts the given value from the current
271	priority, so effects are cumulative.	288	priority, so the effect is cumulative.
		289
272		290
273	=item aio_open $pathname, $flags, $mode, $callback->($fh)	291	=item aio_open $pathname, $flags, $mode, $callback->($fh)
274		292
275	Asynchronously open or create a file and call the callback with a newly	293	Asynchronously open or create a file and call the callback with a newly
276	created filehandle for the file.	294	created filehandle for the file.
…		…
282	list. They are the same as used by C<sysopen>.	300	list. They are the same as used by C<sysopen>.
283		301
284	Likewise, C<$mode> specifies the mode of the newly created file, if it	302	Likewise, C<$mode> specifies the mode of the newly created file, if it
285	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	303	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
286	except that it is mandatory (i.e. use C<0> if you don't create new files,	304	except that it is mandatory (i.e. use C<0> if you don't create new files,
287	and C<0666> or C<0777> if you do).	305	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		306	by the umask in effect then the request is being executed, so better never
		307	change the umask.
288		308
289	Example:	309	Example:
290		310
291	aio_open "/etc/passwd", O_RDONLY, 0, sub {	311	aio_open "/etc/passwd", O_RDONLY, 0, sub {
292	if ($_[0]) {	312	if ($_[0]) {
…		…
295	} else {	315	} else {
296	die "open failed: $!\n";	316	die "open failed: $!\n";
297	}	317	}
298	};	318	};
299		319
		320
300	=item aio_close $fh, $callback->($status)	321	=item aio_close $fh, $callback->($status)
301		322
302	Asynchronously close a file and call the callback with the result	323	Asynchronously close a file and call the callback with the result
303	code. I<WARNING:> although accepted, you should not pass in a perl	324	code.
304	filehandle here, as perl will likely close the file descriptor another
305	time when the filehandle is destroyed. Normally, you can safely call perls
306	C<close> or just let filehandles go out of scope.
307		325
308	This is supposed to be a bug in the API, so that might change. It's	326	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
309	therefore best to avoid this function.	327	closing the file descriptor associated with the filehandle itself.
		328
		329	Therefore, C<aio_close> will not close the filehandle - instead it will
		330	use dup2 to overwrite the file descriptor with the write-end of a pipe
		331	(the pipe fd will be created on demand and will be cached).
		332
		333	Or in other words: the file descriptor will be closed, but it will not be
		334	free for reuse until the perl filehandle is closed.
		335
		336	=cut
310		337
311	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	338	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
312		339
313	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	340	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
314		341
315	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	342	Reads or writes C<$length> bytes from or to the specified C<$fh> and
316	into the scalar given by C<data> and offset C<dataoffset> and calls the	343	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
317	callback without the actual number of bytes read (or -1 on error, just	344	and calls the callback without the actual number of bytes read (or -1 on
318	like the syscall).	345	error, just like the syscall).
		346
		347	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		348	offset plus the actual number of bytes read.
		349
		350	If C<$offset> is undefined, then the current file descriptor offset will
		351	be used (and updated), otherwise the file descriptor offset will not be
		352	changed by these calls.
		353
		354	If C<$length> is undefined in C<aio_write>, use the remaining length of
		355	C<$data>.
		356
		357	If C<$dataoffset> is less than zero, it will be counted from the end of
		358	C<$data>.
319		359
320	The C<$data> scalar I<MUST NOT> be modified in any way while the request	360	The C<$data> scalar I<MUST NOT> be modified in any way while the request
321	is outstanding. Modifying it can result in segfaults or WW3 (if the	361	is outstanding. Modifying it can result in segfaults or World War III (if
322	necessary/optional hardware is installed).	362	the necessary/optional hardware is installed).
323		363
324	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	364	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
325	offset C<0> within the scalar:	365	offset C<0> within the scalar:
326		366
327	aio_read $fh, 7, 15, $buffer, 0, sub {	367	aio_read $fh, 7, 15, $buffer, 0, sub {
328	$_[0] > 0 or die "read error: $!";	368	$_[0] > 0 or die "read error: $!";
329	print "read $_[0] bytes: <$buffer>\n";	369	print "read $_[0] bytes: <$buffer>\n";
330	};	370	};
		371
331		372
332	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	373	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
333		374
334	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	375	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
335	reading at byte offset C<$in_offset>, and starts writing at the current	376	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
339		380
340	This call tries to make use of a native C<sendfile> syscall to provide	381	This call tries to make use of a native C<sendfile> syscall to provide
341	zero-copy operation. For this to work, C<$out_fh> should refer to a	382	zero-copy operation. For this to work, C<$out_fh> should refer to a
342	socket, and C<$in_fh> should refer to mmap'able file.	383	socket, and C<$in_fh> should refer to mmap'able file.
343		384
344	If the native sendfile call fails or is not implemented, it will be	385	If the native sendfile call fails with C<ENOSYS>, C<ENOTSUP>,
		386	C<EOPNOTSUPP> or C<ENOTSOCK>, or is not implemented, it will be emulated,
345	emulated, so you can call C<aio_sendfile> on any type of filehandle	387	so you can call C<aio_sendfile> on any type of filehandle regardless of
346	regardless of the limitations of the operating system.	388	the limitations of the operating system.
347		389
348	Please note, however, that C<aio_sendfile> can read more bytes from	390	Please note, however, that C<aio_sendfile> can read more bytes from
349	C<$in_fh> than are written, and there is no way to find out how many	391	C<$in_fh> than are written, and there is no way to find out how many
350	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	392	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
351	provides the number of bytes written to C<$out_fh>. Only if the result	393	provides the number of bytes written to C<$out_fh>. Only if the result
352	value equals C<$length> one can assume that C<$length> bytes have been	394	value equals C<$length> one can assume that C<$length> bytes have been
353	read.	395	read.
		396
354		397
355	=item aio_readahead $fh,$offset,$length, $callback->($retval)	398	=item aio_readahead $fh,$offset,$length, $callback->($retval)
356		399
357	C<aio_readahead> populates the page cache with data from a file so that	400	C<aio_readahead> populates the page cache with data from a file so that
358	subsequent reads from that file will not block on disk I/O. The C<$offset>	401	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
364	file. The current file offset of the file is left unchanged.	407	file. The current file offset of the file is left unchanged.
365		408
366	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	409	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
367	emulated by simply reading the data, which would have a similar effect.	410	emulated by simply reading the data, which would have a similar effect.
368		411
		412
369	=item aio_stat $fh_or_path, $callback->($status)	413	=item aio_stat $fh_or_path, $callback->($status)
370		414
371	=item aio_lstat $fh, $callback->($status)	415	=item aio_lstat $fh, $callback->($status)
372		416
373	Works like perl's C<stat> or C<lstat> in void context. The callback will	417	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
386	aio_stat "/etc/passwd", sub {	430	aio_stat "/etc/passwd", sub {
387	$_[0] and die "stat failed: $!";	431	$_[0] and die "stat failed: $!";
388	print "size is ", -s _, "\n";	432	print "size is ", -s _, "\n";
389	};	433	};
390		434
		435
		436	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		437
		438	Works like perl's C<utime> function (including the special case of $atime
		439	and $mtime being undef). Fractional times are supported if the underlying
		440	syscalls support them.
		441
		442	When called with a pathname, uses utimes(2) if available, otherwise
		443	utime(2). If called on a file descriptor, uses futimes(2) if available,
		444	otherwise returns ENOSYS, so this is not portable.
		445
		446	Examples:
		447
		448	# set atime and mtime to current time (basically touch(1)):
		449	aio_utime "path", undef, undef;
		450	# set atime to current time and mtime to beginning of the epoch:
		451	aio_utime "path", time, undef; # undef==0
		452
		453
		454	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		455
		456	Works like perl's C<chown> function, except that C<undef> for either $uid
		457	or $gid is being interpreted as "do not change" (but -1 can also be used).
		458
		459	Examples:
		460
		461	# same as "chown root path" in the shell:
		462	aio_chown "path", 0, -1;
		463	# same as above:
		464	aio_chown "path", 0, undef;
		465
		466
		467	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		468
		469	Works like truncate(2) or ftruncate(2).
		470
		471
		472	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		473
		474	Works like perl's C<chmod> function.
		475
		476
391	=item aio_unlink $pathname, $callback->($status)	477	=item aio_unlink $pathname, $callback->($status)
392		478
393	Asynchronously unlink (delete) a file and call the callback with the	479	Asynchronously unlink (delete) a file and call the callback with the
394	result code.	480	result code.
395		481
		482
396	=item aio_mknod $path, $mode, $dev, $callback->($status)	483	=item aio_mknod $path, $mode, $dev, $callback->($status)
397		484
398	[EXPERIMENTAL]	485	[EXPERIMENTAL]
399		486
400	Asynchronously create a device node (or fifo). See mknod(2).	487	Asynchronously create a device node (or fifo). See mknod(2).
401		488
402	The only (POSIX-) portable way of calling this function is:	489	The only (POSIX-) portable way of calling this function is:
403		490
404	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	491	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		492
405		493
406	=item aio_link $srcpath, $dstpath, $callback->($status)	494	=item aio_link $srcpath, $dstpath, $callback->($status)
407		495
408	Asynchronously create a new link to the existing object at C<$srcpath> at	496	Asynchronously create a new link to the existing object at C<$srcpath> at
409	the path C<$dstpath> and call the callback with the result code.	497	the path C<$dstpath> and call the callback with the result code.
410		498
		499
411	=item aio_symlink $srcpath, $dstpath, $callback->($status)	500	=item aio_symlink $srcpath, $dstpath, $callback->($status)
412		501
413	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	502	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
414	the path C<$dstpath> and call the callback with the result code.	503	the path C<$dstpath> and call the callback with the result code.
415		504
		505
		506	=item aio_readlink $path, $callback->($link)
		507
		508	Asynchronously read the symlink specified by C<$path> and pass it to
		509	the callback. If an error occurs, nothing or undef gets passed to the
		510	callback.
		511
		512
416	=item aio_rename $srcpath, $dstpath, $callback->($status)	513	=item aio_rename $srcpath, $dstpath, $callback->($status)
417		514
418	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	515	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
419	rename(2) and call the callback with the result code.	516	rename(2) and call the callback with the result code.
420		517
		518
		519	=item aio_mkdir $pathname, $mode, $callback->($status)
		520
		521	Asynchronously mkdir (create) a directory and call the callback with
		522	the result code. C<$mode> will be modified by the umask at the time the
		523	request is executed, so do not change your umask.
		524
		525
421	=item aio_rmdir $pathname, $callback->($status)	526	=item aio_rmdir $pathname, $callback->($status)
422		527
423	Asynchronously rmdir (delete) a directory and call the callback with the	528	Asynchronously rmdir (delete) a directory and call the callback with the
424	result code.	529	result code.
		530
425		531
426	=item aio_readdir $pathname, $callback->($entries)	532	=item aio_readdir $pathname, $callback->($entries)
427		533
428	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	534	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
429	directory (i.e. opendir + readdir + closedir). The entries will not be	535	directory (i.e. opendir + readdir + closedir). The entries will not be
430	sorted, and will B<NOT> include the C<.> and C<..> entries.	536	sorted, and will B<NOT> include the C<.> and C<..> entries.
431		537
432	The callback a single argument which is either C<undef> or an array-ref	538	The callback is passed a single argument which is either C<undef> or an
433	with the filenames.	539	array-ref with the filenames.
		540
		541
		542	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		543
		544	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		545	behaviour and output format. In case of an error, C<$entries> will be
		546	C<undef>.
		547
		548	The flags are a combination of the following constants, ORed together (the
		549	flags will also be passed to the callback, possibly modified):
		550
		551	=over 4
		552
		553	=item IO::AIO::READDIR_DENTS
		554
		555	When this flag is off, then the callback gets an arrayref with of names
		556	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		557	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		558	entry in more detail.
		559
		560	C<$name> is the name of the entry.
		561
		562	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		563
		564	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		565	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		566	C<IO::AIO::DT_WHT>.
		567
		568	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		569	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		570	scalars are read-only: you can not modify them.
		571
		572	C<$inode> is the inode number (which might not be exact on systems with 64
		573	bit inode numbers and 32 bit perls). This field has unspecified content on
		574	systems that do not deliver the inode information.
		575
		576	=item IO::AIO::READDIR_DIRS_FIRST
		577
		578	When this flag is set, then the names will be returned in an order where
		579	likely directories come first. This is useful when you need to quickly
		580	find directories, or you want to find all directories while avoiding to
		581	stat() each entry.
		582
		583	If the system returns type information in readdir, then this is used
		584	to find directories directly. Otherwise, likely directories are files
		585	beginning with ".", or otherwise files with no dots, of which files with
		586	short names are tried first.
		587
		588	=item IO::AIO::READDIR_STAT_ORDER
		589
		590	When this flag is set, then the names will be returned in an order
		591	suitable for stat()'ing each one. That is, when you plan to stat()
		592	all files in the given directory, then the returned order will likely
		593	be fastest.
		594
		595	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		596	the likely dirs come first, resulting in a less optimal stat order.
		597
		598	=item IO::AIO::READDIR_FOUND_UNKNOWN
		599
		600	This flag should not be set when calling C<aio_readdirx>. Instead, it
		601	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		602	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		603	C<$type>'s are known, which can be used to speed up some algorithms.
		604
		605	=back
		606
		607
		608	=item aio_load $path, $data, $callback->($status)
		609
		610	This is a composite request that tries to fully load the given file into
		611	memory. Status is the same as with aio_read.
		612
		613	=cut
		614
		615	sub aio_load($$;$) {
		616	my ($path, undef, $cb) = @_;
		617	my $data = \$_[1];
		618
		619	my $pri = aioreq_pri;
		620	my $grp = aio_group $cb;
		621
		622	aioreq_pri $pri;
		623	add $grp aio_open $path, O_RDONLY, 0, sub {
		624	my $fh = shift
		625	or return $grp->result (-1);
		626
		627	aioreq_pri $pri;
		628	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		629	$grp->result ($_[0]);
		630	};
		631	};
		632
		633	$grp
		634	}
434		635
435	=item aio_copy $srcpath, $dstpath, $callback->($status)	636	=item aio_copy $srcpath, $dstpath, $callback->($status)
436		637
437	Try to copy the I<file> (directories not supported as either source or	638	Try to copy the I<file> (directories not supported as either source or
438	destination) from C<$srcpath> to C<$dstpath> and call the callback with	639	destination) from C<$srcpath> to C<$dstpath> and call the callback with
439	the C<0> (error) or C<-1> ok.	640	a status of C<0> (ok) or C<-1> (error, see C<$!>).
440		641
441	This is a composite request that it creates the destination file with	642	This is a composite request that creates the destination file with
442	mode 0200 and copies the contents of the source file into it using	643	mode 0200 and copies the contents of the source file into it using
443	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	644	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
444	uid/gid, in that order.	645	uid/gid, in that order.
445		646
446	If an error occurs, the partial destination file will be unlinked, if	647	If an error occurs, the partial destination file will be unlinked, if
…		…
456	my $grp = aio_group $cb;	657	my $grp = aio_group $cb;
457		658
458	aioreq_pri $pri;	659	aioreq_pri $pri;
459	add $grp aio_open $src, O_RDONLY, 0, sub {	660	add $grp aio_open $src, O_RDONLY, 0, sub {
460	if (my $src_fh = $_[0]) {	661	if (my $src_fh = $_[0]) {
461	my @stat = stat $src_fh;	662	my @stat = stat $src_fh; # hmm, might block over nfs?
462		663
463	aioreq_pri $pri;	664	aioreq_pri $pri;
464	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	665	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
465	if (my $dst_fh = $_[0]) {	666	if (my $dst_fh = $_[0]) {
466	aioreq_pri $pri;	667	aioreq_pri $pri;
467	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	668	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
468	if ($_[0] == $stat[7]) {	669	if ($_[0] == $stat[7]) {
469	$grp->result (0);	670	$grp->result (0);
470	close $src_fh;	671	close $src_fh;
471		672
472	# those should not normally block. should. should.	673	my $ch = sub {
		674	aioreq_pri $pri;
		675	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		676	aioreq_pri $pri;
		677	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		678	aioreq_pri $pri;
		679	add $grp aio_close $dst_fh;
		680	}
		681	};
		682	};
		683
		684	aioreq_pri $pri;
		685	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		686	if ($_[0] < 0 && $! == ENOSYS) {
		687	aioreq_pri $pri;
473	utime $stat[8], $stat[9], $dst;	688	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
474	chmod $stat[2] & 07777, $dst_fh;	689	} else {
475	chown $stat[4], $stat[5], $dst_fh;	690	$ch->();
		691	}
476	close $dst_fh;	692	};
477	} else {	693	} else {
478	$grp->result (-1);	694	$grp->result (-1);
479	close $src_fh;	695	close $src_fh;
480	close $dst_fh;	696	close $dst_fh;
481		697
…		…
498		714
499	=item aio_move $srcpath, $dstpath, $callback->($status)	715	=item aio_move $srcpath, $dstpath, $callback->($status)
500		716
501	Try to move the I<file> (directories not supported as either source or	717	Try to move the I<file> (directories not supported as either source or
502	destination) from C<$srcpath> to C<$dstpath> and call the callback with	718	destination) from C<$srcpath> to C<$dstpath> and call the callback with
503	the C<0> (error) or C<-1> ok.	719	a status of C<0> (ok) or C<-1> (error, see C<$!>).
504		720
505	This is a composite request that tries to rename(2) the file first. If	721	This is a composite request that tries to rename(2) the file first; if
506	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	722	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
507	that is successful, unlinking the C<$srcpath>.	723	that is successful, unlinks the C<$srcpath>.
508		724
509	=cut	725	=cut
510		726
511	sub aio_move($$;$) {	727	sub aio_move($$;$) {
512	my ($src, $dst, $cb) = @_;	728	my ($src, $dst, $cb) = @_;
…		…
559		775
560	Implementation notes.	776	Implementation notes.
561		777
562	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	778	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
563		779
		780	If readdir returns file type information, then this is used directly to
		781	find directories.
		782
564	After reading the directory, the modification time, size etc. of the	783	Otherwise, after reading the directory, the modification time, size etc.
565	directory before and after the readdir is checked, and if they match (and	784	of the directory before and after the readdir is checked, and if they
566	isn't the current time), the link count will be used to decide how many	785	match (and isn't the current time), the link count will be used to decide
567	entries are directories (if >= 2). Otherwise, no knowledge of the number	786	how many entries are directories (if >= 2). Otherwise, no knowledge of the
568	of subdirectories will be assumed.	787	number of subdirectories will be assumed.
569		788
570	Then entries will be sorted into likely directories (everything without	789	Then entries will be sorted into likely directories a non-initial dot
571	a non-initial dot currently) and likely non-directories (everything	790	currently) and likely non-directories (see C<aio_readdirx>). Then every
572	else). Then every entry plus an appended C</.> will be C<stat>'ed,	791	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
573	likely directories first. If that succeeds, it assumes that the entry	792	in order of their inode numbers. If that succeeds, it assumes that the
574	is a directory or a symlink to directory (which will be checked	793	entry is a directory or a symlink to directory (which will be checked
575	seperately). This is often faster than stat'ing the entry itself because	794	seperately). This is often faster than stat'ing the entry itself because
576	filesystems might detect the type of the entry without reading the inode	795	filesystems might detect the type of the entry without reading the inode
577	data (e.g. ext2fs filetype feature).	796	data (e.g. ext2fs filetype feature), even on systems that cannot return
		797	the filetype information on readdir.
578		798
579	If the known number of directories (link count - 2) has been reached, the	799	If the known number of directories (link count - 2) has been reached, the
580	rest of the entries is assumed to be non-directories.	800	rest of the entries is assumed to be non-directories.
581		801
582	This only works with certainty on POSIX (= UNIX) filesystems, which	802	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
586	as those tend to return 0 or 1 as link counts, which disables the	806	as those tend to return 0 or 1 as link counts, which disables the
587	directory counting heuristic.	807	directory counting heuristic.
588		808
589	=cut	809	=cut
590		810
591	sub aio_scandir($$$) {	811	sub aio_scandir($$;$) {
592	my ($path, $maxreq, $cb) = @_;	812	my ($path, $maxreq, $cb) = @_;
593		813
594	my $pri = aioreq_pri;	814	my $pri = aioreq_pri;
595		815
596	my $grp = aio_group $cb;	816	my $grp = aio_group $cb;
…		…
604	my $now = time;	824	my $now = time;
605	my $hash1 = join ":", (stat _)[0,1,3,7,9];	825	my $hash1 = join ":", (stat _)[0,1,3,7,9];
606		826
607	# read the directory entries	827	# read the directory entries
608	aioreq_pri $pri;	828	aioreq_pri $pri;
609	add $grp aio_readdir $path, sub {	829	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
610	my $entries = shift	830	my $entries = shift
611	or return $grp->result ();	831	or return $grp->result ();
612		832
613	# stat the dir another time	833	# stat the dir another time
614	aioreq_pri $pri;	834	aioreq_pri $pri;
…		…
620	# take the slow route if anything looks fishy	840	# take the slow route if anything looks fishy
621	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	841	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
622	$ndirs = -1;	842	$ndirs = -1;
623	} else {	843	} else {
624	# if nlink == 2, we are finished	844	# if nlink == 2, we are finished
625	# on non-posix-fs's, we rely on nlink < 2	845	# for non-posix-fs's, we rely on nlink < 2
626	$ndirs = (stat _)[3] - 2	846	$ndirs = (stat _)[3] - 2
627	or return $grp->result ([], $entries);	847	or return $grp->result ([], $entries);
628	}	848	}
629		849
630	# sort into likely dirs and likely nondirs
631	# dirs == files without ".", short entries first
632	$entries = [map $_->[0],
633	sort { $b->[1] cmp $a->[1] }
634	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
635	@$entries];
636
637	my (@dirs, @nondirs);	850	my (@dirs, @nondirs);
638		851
639	my $statgrp = add $grp aio_group sub {	852	my $statgrp = add $grp aio_group sub {
640	$grp->result (\@dirs, \@nondirs);	853	$grp->result (\@dirs, \@nondirs);
641	};	854	};
642		855
643	limit $statgrp $maxreq;	856	limit $statgrp $maxreq;
644	feed $statgrp sub {	857	feed $statgrp sub {
645	return unless @$entries;	858	return unless @$entries;
646	my $entry = pop @$entries;	859	my $entry = shift @$entries;
647		860
648	aioreq_pri $pri;	861	aioreq_pri $pri;
649	add $statgrp aio_stat "$path/$entry/.", sub {	862	add $statgrp aio_stat "$path/$entry/.", sub {
650	if ($_[0] < 0) {	863	if ($_[0] < 0) {
651	push @nondirs, $entry;	864	push @nondirs, $entry;
…		…
672	};	885	};
673		886
674	$grp	887	$grp
675	}	888	}
676		889
		890	=item aio_rmtree $path, $callback->($status)
		891
		892	Delete a directory tree starting (and including) C<$path>, return the
		893	status of the final C<rmdir> only. This is a composite request that
		894	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		895	everything else.
		896
		897	=cut
		898
		899	sub aio_rmtree;
		900	sub aio_rmtree($;$) {
		901	my ($path, $cb) = @_;
		902
		903	my $pri = aioreq_pri;
		904	my $grp = aio_group $cb;
		905
		906	aioreq_pri $pri;
		907	add $grp aio_scandir $path, 0, sub {
		908	my ($dirs, $nondirs) = @_;
		909
		910	my $dirgrp = aio_group sub {
		911	add $grp aio_rmdir $path, sub {
		912	$grp->result ($_[0]);
		913	};
		914	};
		915
		916	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		917	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		918
		919	add $grp $dirgrp;
		920	};
		921
		922	$grp
		923	}
		924
		925	=item aio_sync $callback->($status)
		926
		927	Asynchronously call sync and call the callback when finished.
		928
677	=item aio_fsync $fh, $callback->($status)	929	=item aio_fsync $fh, $callback->($status)
678		930
679	Asynchronously call fsync on the given filehandle and call the callback	931	Asynchronously call fsync on the given filehandle and call the callback
680	with the fsync result code.	932	with the fsync result code.
681		933
…		…
684	Asynchronously call fdatasync on the given filehandle and call the	936	Asynchronously call fdatasync on the given filehandle and call the
685	callback with the fdatasync result code.	937	callback with the fdatasync result code.
686		938
687	If this call isn't available because your OS lacks it or it couldn't be	939	If this call isn't available because your OS lacks it or it couldn't be
688	detected, it will be emulated by calling C<fsync> instead.	940	detected, it will be emulated by calling C<fsync> instead.
		941
		942	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		943
		944	Sync the data portion of the file specified by C<$offset> and C<$length>
		945	to disk (but NOT the metadata), by calling the Linux-specific
		946	sync_file_range call. If sync_file_range is not available or it returns
		947	ENOSYS, then fdatasync or fsync is being substituted.
		948
		949	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		950	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		951	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		952	manpage for details.
		953
		954	=item aio_pathsync $path, $callback->($status)
		955
		956	This request tries to open, fsync and close the given path. This is a
		957	composite request intended to sync directories after directory operations
		958	(E.g. rename). This might not work on all operating systems or have any
		959	specific effect, but usually it makes sure that directory changes get
		960	written to disc. It works for anything that can be opened for read-only,
		961	not just directories.
		962
		963	Future versions of this function might fall back to other methods when
		964	C<fsync> on the directory fails (such as calling C<sync>).
		965
		966	Passes C<0> when everything went ok, and C<-1> on error.
		967
		968	=cut
		969
		970	sub aio_pathsync($;$) {
		971	my ($path, $cb) = @_;
		972
		973	my $pri = aioreq_pri;
		974	my $grp = aio_group $cb;
		975
		976	aioreq_pri $pri;
		977	add $grp aio_open $path, O_RDONLY, 0, sub {
		978	my ($fh) = @_;
		979	if ($fh) {
		980	aioreq_pri $pri;
		981	add $grp aio_fsync $fh, sub {
		982	$grp->result ($_[0]);
		983
		984	aioreq_pri $pri;
		985	add $grp aio_close $fh;
		986	};
		987	} else {
		988	$grp->result (-1);
		989	}
		990	};
		991
		992	$grp
		993	}
689		994
690	=item aio_group $callback->(...)	995	=item aio_group $callback->(...)
691		996
692	This is a very special aio request: Instead of doing something, it is a	997	This is a very special aio request: Instead of doing something, it is a
693	container for other aio requests, which is useful if you want to bundle	998	container for other aio requests, which is useful if you want to bundle
…		…
743	=item cancel $req	1048	=item cancel $req
744		1049
745	Cancels the request, if possible. Has the effect of skipping execution	1050	Cancels the request, if possible. Has the effect of skipping execution
746	when entering the B<execute> state and skipping calling the callback when	1051	when entering the B<execute> state and skipping calling the callback when
747	entering the the B<result> state, but will leave the request otherwise	1052	entering the the B<result> state, but will leave the request otherwise
748	untouched. That means that requests that currently execute will not be	1053	untouched (with the exception of readdir). That means that requests that
749	stopped and resources held by the request will not be freed prematurely.	1054	currently execute will not be stopped and resources held by the request
		1055	will not be freed prematurely.
750		1056
751	=item cb $req $callback->(...)	1057	=item cb $req $callback->(...)
752		1058
753	Replace (or simply set) the callback registered to the request.	1059	Replace (or simply set) the callback registered to the request.
754		1060
…		…
805	Their lifetime, simplified, looks like this: when they are empty, they	1111	Their lifetime, simplified, looks like this: when they are empty, they
806	will finish very quickly. If they contain only requests that are in the	1112	will finish very quickly. If they contain only requests that are in the
807	C<done> state, they will also finish. Otherwise they will continue to	1113	C<done> state, they will also finish. Otherwise they will continue to
808	exist.	1114	exist.
809		1115
810	That means after creating a group you have some time to add requests. And	1116	That means after creating a group you have some time to add requests
811	in the callbacks of those requests, you can add further requests to the	1117	(precisely before the callback has been invoked, which is only done within
812	group. And only when all those requests have finished will the the group	1118	the C<poll_cb>). And in the callbacks of those requests, you can add
813	itself finish.	1119	further requests to the group. And only when all those requests have
		1120	finished will the the group itself finish.
814		1121
815	=over 4	1122	=over 4
816		1123
817	=item add $grp ...	1124	=item add $grp ...
818		1125
…		…
827	=item $grp->cancel_subs	1134	=item $grp->cancel_subs
828		1135
829	Cancel all subrequests and clears any feeder, but not the group request	1136	Cancel all subrequests and clears any feeder, but not the group request
830	itself. Useful when you queued a lot of events but got a result early.	1137	itself. Useful when you queued a lot of events but got a result early.
831		1138
		1139	The group request will finish normally (you cannot add requests to the
		1140	group).
		1141
832	=item $grp->result (...)	1142	=item $grp->result (...)
833		1143
834	Set the result value(s) that will be passed to the group callback when all	1144	Set the result value(s) that will be passed to the group callback when all
835	subrequests have finished and set thre groups errno to the current value	1145	subrequests have finished and set the groups errno to the current value
836	of errno (just like calling C<errno> without an error number). By default,	1146	of errno (just like calling C<errno> without an error number). By default,
837	no argument will be passed and errno is zero.	1147	no argument will be passed and errno is zero.
838		1148
839	=item $grp->errno ([$errno])	1149	=item $grp->errno ([$errno])
840		1150
…		…
851	=item feed $grp $callback->($grp)	1161	=item feed $grp $callback->($grp)
852		1162
853	Sets a feeder/generator on this group: every group can have an attached	1163	Sets a feeder/generator on this group: every group can have an attached
854	generator that generates requests if idle. The idea behind this is that,	1164	generator that generates requests if idle. The idea behind this is that,
855	although you could just queue as many requests as you want in a group,	1165	although you could just queue as many requests as you want in a group,
856	this might starve other requests for a potentially long time. For	1166	this might starve other requests for a potentially long time. For example,
857	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1167	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
858	requests, delaying any later requests for a long time.	1168	delaying any later requests for a long time.
859		1169
860	To avoid this, and allow incremental generation of requests, you can	1170	To avoid this, and allow incremental generation of requests, you can
861	instead a group and set a feeder on it that generates those requests. The	1171	instead a group and set a feeder on it that generates those requests. The
862	feed callback will be called whenever there are few enough (see C<limit>,	1172	feed callback will be called whenever there are few enough (see C<limit>,
863	below) requests active in the group itself and is expected to queue more	1173	below) requests active in the group itself and is expected to queue more
…		…
867	not impose any limits).	1177	not impose any limits).
868		1178
869	If the feed does not queue more requests when called, it will be	1179	If the feed does not queue more requests when called, it will be
870	automatically removed from the group.	1180	automatically removed from the group.
871		1181
872	If the feed limit is C<0>, it will be set to C<2> automatically.	1182	If the feed limit is C<0> when this method is called, it will be set to
		1183	C<2> automatically.
873		1184
874	Example:	1185	Example:
875		1186
876	# stat all files in @files, but only ever use four aio requests concurrently:	1187	# stat all files in @files, but only ever use four aio requests concurrently:
877		1188
…		…
889	Sets the feeder limit for the group: The feeder will be called whenever	1200	Sets the feeder limit for the group: The feeder will be called whenever
890	the group contains less than this many requests.	1201	the group contains less than this many requests.
891		1202
892	Setting the limit to C<0> will pause the feeding process.	1203	Setting the limit to C<0> will pause the feeding process.
893		1204
		1205	The default value for the limit is C<0>, but note that setting a feeder
		1206	automatically bumps it up to C<2>.
		1207
894	=back	1208	=back
895		1209
896	=head2 SUPPORT FUNCTIONS	1210	=head2 SUPPORT FUNCTIONS
897		1211
898	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1212	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
900	=over 4	1214	=over 4
901		1215
902	=item $fileno = IO::AIO::poll_fileno	1216	=item $fileno = IO::AIO::poll_fileno
903		1217
904	Return the I<request result pipe file descriptor>. This filehandle must be	1218	Return the I<request result pipe file descriptor>. This filehandle must be
905	polled for reading by some mechanism outside this module (e.g. Event or	1219	polled for reading by some mechanism outside this module (e.g. EV, Glib,
906	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1220	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
907	to call C<poll_cb> to check the results.	1221	you have to call C<poll_cb> to check the results.
908		1222
909	See C<poll_cb> for an example.	1223	See C<poll_cb> for an example.
910		1224
911	=item IO::AIO::poll_cb	1225	=item IO::AIO::poll_cb
912		1226
913	Process some outstanding events on the result pipe. You have to call this	1227	Process some outstanding events on the result pipe. You have to call this
914	regularly. Returns the number of events processed. Returns immediately	1228	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1229	returned earlier for whatever reason. Returns immediately when no events
915	when no events are outstanding. The amount of events processed depends on	1230	are outstanding. The amount of events processed depends on the settings of
916	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1231	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
917		1232
918	If not all requests were processed for whatever reason, the filehandle	1233	If not all requests were processed for whatever reason, the filehandle
919	will still be ready when C<poll_cb> returns.	1234	will still be ready when C<poll_cb> returns, so normally you don't have to
		1235	do anything special to have it called later.
920		1236
921	Example: Install an Event watcher that automatically calls	1237	Example: Install an Event watcher that automatically calls
922	IO::AIO::poll_cb with high priority:	1238	IO::AIO::poll_cb with high priority (more examples can be found in the
		1239	SYNOPSIS section, at the top of this document):
923		1240
924	Event->io (fd => IO::AIO::poll_fileno,	1241	Event->io (fd => IO::AIO::poll_fileno,
925	poll => 'r', async => 1,	1242	poll => 'r', async => 1,
926	cb => \&IO::AIO::poll_cb);	1243	cb => \&IO::AIO::poll_cb);
927		1244
…		…
933	that are being processed by C<IO::AIO::poll_cb> in one call, respectively	1250	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
934	the maximum amount of time (default C<0>, meaning infinity) spent in	1251	the maximum amount of time (default C<0>, meaning infinity) spent in
935	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount	1252	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
936	of time C<poll_cb> is allowed to use).	1253	of time C<poll_cb> is allowed to use).
937		1254
		1255	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1256	syscall per request processed, which is not normally a problem unless your
		1257	callbacks are really really fast or your OS is really really slow (I am
		1258	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1259
938	Setting these is useful if you want to ensure some level of	1260	Setting these is useful if you want to ensure some level of
939	interactiveness when perl is not fast enough to process all requests in	1261	interactiveness when perl is not fast enough to process all requests in
940	time.	1262	time.
941		1263
942	For interactive programs, values such as C<0.01> to C<0.1> should be fine.	1264	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
943		1265
944	Example: Install an Event watcher that automatically calls	1266	Example: Install an Event watcher that automatically calls
945	IO::AIO::poll_some with low priority, to ensure that other parts of the	1267	IO::AIO::poll_cb with low priority, to ensure that other parts of the
946	program get the CPU sometimes even under high AIO load.	1268	program get the CPU sometimes even under high AIO load.
947		1269
948	# try not to spend much more than 0.1s in poll_cb	1270	# try not to spend much more than 0.1s in poll_cb
949	IO::AIO::max_poll_time 0.1;	1271	IO::AIO::max_poll_time 0.1;
950		1272
…		…
953	poll => 'r', nice => 1,	1275	poll => 'r', nice => 1,
954	cb => &IO::AIO::poll_cb);	1276	cb => &IO::AIO::poll_cb);
955		1277
956	=item IO::AIO::poll_wait	1278	=item IO::AIO::poll_wait
957		1279
		1280	If there are any outstanding requests and none of them in the result
958	Wait till the result filehandle becomes ready for reading (simply does a	1281	phase, wait till the result filehandle becomes ready for reading (simply
959	C<select> on the filehandle. This is useful if you want to synchronously	1282	does a C<select> on the filehandle. This is useful if you want to
960	wait for some requests to finish).	1283	synchronously wait for some requests to finish).
961		1284
962	See C<nreqs> for an example.	1285	See C<nreqs> for an example.
963		1286
964	=item IO::AIO::poll	1287	=item IO::AIO::poll
965		1288
966	Waits until some requests have been handled.	1289	Waits until some requests have been handled.
967		1290
		1291	Returns the number of requests processed, but is otherwise strictly
968	Strictly equivalent to:	1292	equivalent to:
969		1293
970	IO::AIO::poll_wait, IO::AIO::poll_cb	1294	IO::AIO::poll_wait, IO::AIO::poll_cb
971	if IO::AIO::nreqs;
972		1295
973	=item IO::AIO::flush	1296	=item IO::AIO::flush
974		1297
975	Wait till all outstanding AIO requests have been handled.	1298	Wait till all outstanding AIO requests have been handled.
976		1299
977	Strictly equivalent to:	1300	Strictly equivalent to:
978		1301
979	IO::AIO::poll_wait, IO::AIO::poll_cb	1302	IO::AIO::poll_wait, IO::AIO::poll_cb
980	while IO::AIO::nreqs;	1303	while IO::AIO::nreqs;
981		1304
		1305	=back
		1306
982	=head3 CONTROLLING THE NUMBER OF THREADS	1307	=head3 CONTROLLING THE NUMBER OF THREADS
		1308
		1309	=over
983		1310
984	=item IO::AIO::min_parallel $nthreads	1311	=item IO::AIO::min_parallel $nthreads
985		1312
986	Set the minimum number of AIO threads to C<$nthreads>. The current	1313	Set the minimum number of AIO threads to C<$nthreads>. The current
987	default is C<8>, which means eight asynchronous operations can execute	1314	default is C<8>, which means eight asynchronous operations can execute
…		…
1028		1355
1029	The default is probably ok in most situations, especially if thread	1356	The default is probably ok in most situations, especially if thread
1030	creation is fast. If thread creation is very slow on your system you might	1357	creation is fast. If thread creation is very slow on your system you might
1031	want to use larger values.	1358	want to use larger values.
1032		1359
1033	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1360	=item IO::AIO::max_outstanding $maxreqs
1034		1361
1035	This is a very bad function to use in interactive programs because it	1362	This is a very bad function to use in interactive programs because it
1036	blocks, and a bad way to reduce concurrency because it is inexact: Better	1363	blocks, and a bad way to reduce concurrency because it is inexact: Better
1037	use an C<aio_group> together with a feed callback.	1364	use an C<aio_group> together with a feed callback.
1038		1365
1039	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1366	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1040	to queue up more than this number of requests, the next call to the	1367	do queue up more than this number of requests, the next call to the
1041	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1368	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1042	function will block until the limit is no longer exceeded.	1369	function will block until the limit is no longer exceeded.
1043		1370
1044	The default value is very large, so there is no practical limit on the	1371	The default value is very large, so there is no practical limit on the
1045	number of outstanding requests.	1372	number of outstanding requests.
1046		1373
1047	You can still queue as many requests as you want. Therefore,	1374	You can still queue as many requests as you want. Therefore,
1048	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1375	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1049	as a stop gap to shield against fatal memory overflow (with large values).	1376	as a stop gap to shield against fatal memory overflow (with large values).
1050		1377
		1378	=back
		1379
1051	=head3 STATISTICAL INFORMATION	1380	=head3 STATISTICAL INFORMATION
		1381
		1382	=over
1052		1383
1053	=item IO::AIO::nreqs	1384	=item IO::AIO::nreqs
1054		1385
1055	Returns the number of requests currently in the ready, execute or pending	1386	Returns the number of requests currently in the ready, execute or pending
1056	states (i.e. for which their callback has not been invoked yet).	1387	states (i.e. for which their callback has not been invoked yet).
…		…
1070	Returns the number of requests currently in the pending state (executed,	1401	Returns the number of requests currently in the pending state (executed,
1071	but not yet processed by poll_cb).	1402	but not yet processed by poll_cb).
1072		1403
1073	=back	1404	=back
1074		1405
		1406	=head3 MISCELLANEOUS FUNCTIONS
		1407
		1408	IO::AIO implements some functions that might be useful, but are not
		1409	asynchronous.
		1410
		1411	=over 4
		1412
		1413	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1414
		1415	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1416	but is blocking (this makes most sense if you know the input data is
		1417	likely cached already and the output filehandle is set to non-blocking
		1418	operations).
		1419
		1420	Returns the number of bytes copied, or C<-1> on error.
		1421
		1422	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1423
		1424	Simply calls the C<posix_fadvise> function (see it's
		1425	manpage for details). The following advice constants are
		1426	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1427	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1428	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1429
		1430	On systems that do not implement C<posix_fadvise>, this function returns
		1431	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1432
		1433	=back
		1434
1075	=cut	1435	=cut
1076		1436
1077	# support function to convert a fd into a perl filehandle
1078	sub _fd2fh {
1079	return undef if $_[0] < 0;
1080
1081	# try to generate nice filehandles
1082	my $sym = "IO::AIO::fd#$_[0]";
1083	local *$sym;
1084
1085	open *$sym, "+<&=$_[0]" # usually works under any unix
1086	or open *$sym, "<&=$_[0]" # cygwin needs this
1087	or open *$sym, ">&=$_[0]" # or this
1088	or return undef;
1089
1090	*$sym
1091	}
1092
1093	min_parallel 8;	1437	min_parallel 8;
1094		1438
1095	END {	1439	END { flush }
1096	min_parallel 1;
1097	flush;
1098	};
1099		1440
1100	1;	1441	1;
1101		1442
1102	=head2 FORK BEHAVIOUR	1443	=head2 FORK BEHAVIOUR
1103		1444
…		…
1123	bytes of memory. In addition, stat requests need a stat buffer (possibly	1464	bytes of memory. In addition, stat requests need a stat buffer (possibly
1124	a few hundred bytes), readdir requires a result buffer and so on. Perl	1465	a few hundred bytes), readdir requires a result buffer and so on. Perl
1125	scalars and other data passed into aio requests will also be locked and	1466	scalars and other data passed into aio requests will also be locked and
1126	will consume memory till the request has entered the done state.	1467	will consume memory till the request has entered the done state.
1127		1468
1128	This is now awfully much, so queuing lots of requests is not usually a	1469	This is not awfully much, so queuing lots of requests is not usually a
1129	problem.	1470	problem.
1130		1471
1131	Per-thread usage:	1472	Per-thread usage:
1132		1473
1133	In the execution phase, some aio requests require more memory for	1474	In the execution phase, some aio requests require more memory for
…		…
1138		1479
1139	Known bugs will be fixed in the next release.	1480	Known bugs will be fixed in the next release.
1140		1481
1141	=head1 SEE ALSO	1482	=head1 SEE ALSO
1142		1483
1143	L<Coro::AIO>.	1484	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1485	more natural syntax.
1144		1486
1145	=head1 AUTHOR	1487	=head1 AUTHOR
1146		1488
1147	Marc Lehmann <schmorp@schmorp.de>	1489	Marc Lehmann <schmorp@schmorp.de>
1148	http://home.schmorp.de/	1490	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs. Revision 1.169 by root, Sat Jan 2 13:02:20 2010 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs.
Revision 1.169 by root, Sat Jan 2 13:02:20 2010 UTC