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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.88 by root, Sun Oct 29 01:50:29 2006 UTC vs.
Revision 1.172 by root, Thu Jan 7 18:08:21 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.
…		…
182		184
183	=cut	185	=cut
184		186
185	package IO::AIO;	187	package IO::AIO;
186		188
187	no warnings;	189	use Carp ();
188	use strict 'vars';	190
		191	use common::sense;
189		192
190	use base 'Exporter';	193	use base 'Exporter';
191		194
192	BEGIN {	195	BEGIN {
193	our $VERSION = '2.1';	196	our $VERSION = '3.4';
194		197
195	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
196	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
197	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	200	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
198	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	aio_msync aio_mtouch aio_statvfs);
		206
199	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	207	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
200	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	208	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
201	min_parallel max_parallel max_idle	209	min_parallel max_parallel max_idle
202	nreqs nready npending nthreads	210	nreqs nready npending nthreads
203	max_poll_time max_poll_reqs);	211	max_poll_time max_poll_reqs
		212	sendfile fadvise);
		213
		214	push @AIO_REQ, qw(aio_busy); # not exported
204		215
205	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
206		217
207	require XSLoader;	218	require XSLoader;
208	XSLoader::load ("IO::AIO", $VERSION);	219	XSLoader::load ("IO::AIO", $VERSION);
…		…
215	All the C<aio_*> calls are more or less thin wrappers around the syscall	226	All the C<aio_*> calls are more or less thin wrappers around the syscall
216	with the same name (sans C<aio_>). The arguments are similar or identical,	227	with the same name (sans C<aio_>). The arguments are similar or identical,
217	and they all accept an additional (and optional) C<$callback> argument	228	and they all accept an additional (and optional) C<$callback> argument
218	which must be a code reference. This code reference will get called with	229	which must be a code reference. This code reference will get called with
219	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	230	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
220	perl, which usually delivers "false") as it's sole argument when the given	231	perl, which usually delivers "false") as its sole argument after the given
221	syscall has been executed asynchronously.	232	syscall has been executed asynchronously.
222		233
223	All functions expecting a filehandle keep a copy of the filehandle	234	All functions expecting a filehandle keep a copy of the filehandle
224	internally until the request has finished.	235	internally until the request has finished.
225		236
…		…
239	your pathnames to the locale (or other) encoding in effect in the user	250	your pathnames to the locale (or other) encoding in effect in the user
240	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	251	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
241	use something else to ensure your scalar has the correct contents.	252	use something else to ensure your scalar has the correct contents.
242		253
243	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	254	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
244	handles correctly wether it is set or not.	255	handles correctly whether it is set or not.
245		256
246	=over 4	257	=over 4
247		258
248	=item $prev_pri = aioreq_pri [$pri]	259	=item $prev_pri = aioreq_pri [$pri]
249		260
…		…
269	aio_read $_[0], ..., sub {	280	aio_read $_[0], ..., sub {
270	...	281	...
271	};	282	};
272	};	283	};
273		284
		285
274	=item aioreq_nice $pri_adjust	286	=item aioreq_nice $pri_adjust
275		287
276	Similar to C<aioreq_pri>, but subtracts the given value from the current	288	Similar to C<aioreq_pri>, but subtracts the given value from the current
277	priority, so the effect is cumulative.	289	priority, so the effect is cumulative.
		290
278		291
279	=item aio_open $pathname, $flags, $mode, $callback->($fh)	292	=item aio_open $pathname, $flags, $mode, $callback->($fh)
280		293
281	Asynchronously open or create a file and call the callback with a newly	294	Asynchronously open or create a file and call the callback with a newly
282	created filehandle for the file.	295	created filehandle for the file.
…		…
288	list. They are the same as used by C<sysopen>.	301	list. They are the same as used by C<sysopen>.
289		302
290	Likewise, C<$mode> specifies the mode of the newly created file, if it	303	Likewise, C<$mode> specifies the mode of the newly created file, if it
291	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	304	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
292	except that it is mandatory (i.e. use C<0> if you don't create new files,	305	except that it is mandatory (i.e. use C<0> if you don't create new files,
293	and C<0666> or C<0777> if you do).	306	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		307	by the umask in effect then the request is being executed, so better never
		308	change the umask.
294		309
295	Example:	310	Example:
296		311
297	aio_open "/etc/passwd", O_RDONLY, 0, sub {	312	aio_open "/etc/passwd", O_RDONLY, 0, sub {
298	if ($_[0]) {	313	if ($_[0]) {
…		…
301	} else {	316	} else {
302	die "open failed: $!\n";	317	die "open failed: $!\n";
303	}	318	}
304	};	319	};
305		320
		321
306	=item aio_close $fh, $callback->($status)	322	=item aio_close $fh, $callback->($status)
307		323
308	Asynchronously close a file and call the callback with the result	324	Asynchronously close a file and call the callback with the result
309	code. I<WARNING:> although accepted, you should not pass in a perl	325	code.
310	filehandle here, as perl will likely close the file descriptor another
311	time when the filehandle is destroyed. Normally, you can safely call perls
312	C<close> or just let filehandles go out of scope.
313		326
314	This is supposed to be a bug in the API, so that might change. It's	327	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
315	therefore best to avoid this function.	328	closing the file descriptor associated with the filehandle itself.
		329
		330	Therefore, C<aio_close> will not close the filehandle - instead it will
		331	use dup2 to overwrite the file descriptor with the write-end of a pipe
		332	(the pipe fd will be created on demand and will be cached).
		333
		334	Or in other words: the file descriptor will be closed, but it will not be
		335	free for reuse until the perl filehandle is closed.
		336
		337	=cut
316		338
317	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	339	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
318		340
319	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	341	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320		342
321	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	343	Reads or writes C<$length> bytes from or to the specified C<$fh> and
322	into the scalar given by C<data> and offset C<dataoffset> and calls the	344	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
323	callback without the actual number of bytes read (or -1 on error, just	345	and calls the callback without the actual number of bytes read (or -1 on
324	like the syscall).	346	error, just like the syscall).
		347
		348	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		349	offset plus the actual number of bytes read.
		350
		351	If C<$offset> is undefined, then the current file descriptor offset will
		352	be used (and updated), otherwise the file descriptor offset will not be
		353	changed by these calls.
		354
		355	If C<$length> is undefined in C<aio_write>, use the remaining length of
		356	C<$data>.
		357
		358	If C<$dataoffset> is less than zero, it will be counted from the end of
		359	C<$data>.
325		360
326	The C<$data> scalar I<MUST NOT> be modified in any way while the request	361	The C<$data> scalar I<MUST NOT> be modified in any way while the request
327	is outstanding. Modifying it can result in segfaults or WW3 (if the	362	is outstanding. Modifying it can result in segfaults or World War III (if
328	necessary/optional hardware is installed).	363	the necessary/optional hardware is installed).
329		364
330	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	365	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
331	offset C<0> within the scalar:	366	offset C<0> within the scalar:
332		367
333	aio_read $fh, 7, 15, $buffer, 0, sub {	368	aio_read $fh, 7, 15, $buffer, 0, sub {
334	$_[0] > 0 or die "read error: $!";	369	$_[0] > 0 or die "read error: $!";
335	print "read $_[0] bytes: <$buffer>\n";	370	print "read $_[0] bytes: <$buffer>\n";
336	};	371	};
		372
337		373
338	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	374	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
339		375
340	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	376	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
341	reading at byte offset C<$in_offset>, and starts writing at the current	377	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
345		381
346	This call tries to make use of a native C<sendfile> syscall to provide	382	This call tries to make use of a native C<sendfile> syscall to provide
347	zero-copy operation. For this to work, C<$out_fh> should refer to a	383	zero-copy operation. For this to work, C<$out_fh> should refer to a
348	socket, and C<$in_fh> should refer to mmap'able file.	384	socket, and C<$in_fh> should refer to mmap'able file.
349		385
350	If the native sendfile call fails or is not implemented, it will be	386	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		387	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
351	emulated, so you can call C<aio_sendfile> on any type of filehandle	388	it will be emulated, so you can call C<aio_sendfile> on any type of
352	regardless of the limitations of the operating system.	389	filehandle regardless of the limitations of the operating system.
353		390
354	Please note, however, that C<aio_sendfile> can read more bytes from	391	Please note, however, that C<aio_sendfile> can read more bytes from
355	C<$in_fh> than are written, and there is no way to find out how many	392	C<$in_fh> than are written, and there is no way to find out how many
356	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	393	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
357	provides the number of bytes written to C<$out_fh>. Only if the result	394	provides the number of bytes written to C<$out_fh>. Only if the result
358	value equals C<$length> one can assume that C<$length> bytes have been	395	value equals C<$length> one can assume that C<$length> bytes have been
359	read.	396	read.
		397
360		398
361	=item aio_readahead $fh,$offset,$length, $callback->($retval)	399	=item aio_readahead $fh,$offset,$length, $callback->($retval)
362		400
363	C<aio_readahead> populates the page cache with data from a file so that	401	C<aio_readahead> populates the page cache with data from a file so that
364	subsequent reads from that file will not block on disk I/O. The C<$offset>	402	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
370	file. The current file offset of the file is left unchanged.	408	file. The current file offset of the file is left unchanged.
371		409
372	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	410	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
373	emulated by simply reading the data, which would have a similar effect.	411	emulated by simply reading the data, which would have a similar effect.
374		412
		413
375	=item aio_stat $fh_or_path, $callback->($status)	414	=item aio_stat $fh_or_path, $callback->($status)
376		415
377	=item aio_lstat $fh, $callback->($status)	416	=item aio_lstat $fh, $callback->($status)
378		417
379	Works like perl's C<stat> or C<lstat> in void context. The callback will	418	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
392	aio_stat "/etc/passwd", sub {	431	aio_stat "/etc/passwd", sub {
393	$_[0] and die "stat failed: $!";	432	$_[0] and die "stat failed: $!";
394	print "size is ", -s _, "\n";	433	print "size is ", -s _, "\n";
395	};	434	};
396		435
		436
		437	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		438
		439	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		440	whether a file handle or path was passed.
		441
		442	On success, the callback is passed a hash reference with the following
		443	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		444	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		445	is passed.
		446
		447	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		448	C<ST_NOSUID>.
		449
		450	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		451	their correct value when available, or to C<0> on systems that do
		452	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		453	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		454	C<ST_NODIRATIME> and C<ST_RELATIME>.
		455
		456	Example: stat C</wd> and dump out the data if successful.
		457
		458	aio_statvfs "/wd", sub {
		459	my $f = $_[0]
		460	or die "statvfs: $!";
		461
		462	use Data::Dumper;
		463	say Dumper $f;
		464	};
		465
		466	# result:
		467	{
		468	bsize => 1024,
		469	bfree => 4333064312,
		470	blocks => 10253828096,
		471	files => 2050765568,
		472	flag => 4096,
		473	favail => 2042092649,
		474	bavail => 4333064312,
		475	ffree => 2042092649,
		476	namemax => 255,
		477	frsize => 1024,
		478	fsid => 1810
		479	}
		480
		481
		482	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		483
		484	Works like perl's C<utime> function (including the special case of $atime
		485	and $mtime being undef). Fractional times are supported if the underlying
		486	syscalls support them.
		487
		488	When called with a pathname, uses utimes(2) if available, otherwise
		489	utime(2). If called on a file descriptor, uses futimes(2) if available,
		490	otherwise returns ENOSYS, so this is not portable.
		491
		492	Examples:
		493
		494	# set atime and mtime to current time (basically touch(1)):
		495	aio_utime "path", undef, undef;
		496	# set atime to current time and mtime to beginning of the epoch:
		497	aio_utime "path", time, undef; # undef==0
		498
		499
		500	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		501
		502	Works like perl's C<chown> function, except that C<undef> for either $uid
		503	or $gid is being interpreted as "do not change" (but -1 can also be used).
		504
		505	Examples:
		506
		507	# same as "chown root path" in the shell:
		508	aio_chown "path", 0, -1;
		509	# same as above:
		510	aio_chown "path", 0, undef;
		511
		512
		513	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		514
		515	Works like truncate(2) or ftruncate(2).
		516
		517
		518	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		519
		520	Works like perl's C<chmod> function.
		521
		522
397	=item aio_unlink $pathname, $callback->($status)	523	=item aio_unlink $pathname, $callback->($status)
398		524
399	Asynchronously unlink (delete) a file and call the callback with the	525	Asynchronously unlink (delete) a file and call the callback with the
400	result code.	526	result code.
401		527
		528
402	=item aio_mknod $path, $mode, $dev, $callback->($status)	529	=item aio_mknod $path, $mode, $dev, $callback->($status)
403		530
404	[EXPERIMENTAL]	531	[EXPERIMENTAL]
405		532
406	Asynchronously create a device node (or fifo). See mknod(2).	533	Asynchronously create a device node (or fifo). See mknod(2).
407		534
408	The only (POSIX-) portable way of calling this function is:	535	The only (POSIX-) portable way of calling this function is:
409		536
410	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	537	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		538
411		539
412	=item aio_link $srcpath, $dstpath, $callback->($status)	540	=item aio_link $srcpath, $dstpath, $callback->($status)
413		541
414	Asynchronously create a new link to the existing object at C<$srcpath> at	542	Asynchronously create a new link to the existing object at C<$srcpath> at
415	the path C<$dstpath> and call the callback with the result code.	543	the path C<$dstpath> and call the callback with the result code.
416		544
		545
417	=item aio_symlink $srcpath, $dstpath, $callback->($status)	546	=item aio_symlink $srcpath, $dstpath, $callback->($status)
418		547
419	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	548	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
420	the path C<$dstpath> and call the callback with the result code.	549	the path C<$dstpath> and call the callback with the result code.
421		550
		551
		552	=item aio_readlink $path, $callback->($link)
		553
		554	Asynchronously read the symlink specified by C<$path> and pass it to
		555	the callback. If an error occurs, nothing or undef gets passed to the
		556	callback.
		557
		558
422	=item aio_rename $srcpath, $dstpath, $callback->($status)	559	=item aio_rename $srcpath, $dstpath, $callback->($status)
423		560
424	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	561	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
425	rename(2) and call the callback with the result code.	562	rename(2) and call the callback with the result code.
426		563
		564
		565	=item aio_mkdir $pathname, $mode, $callback->($status)
		566
		567	Asynchronously mkdir (create) a directory and call the callback with
		568	the result code. C<$mode> will be modified by the umask at the time the
		569	request is executed, so do not change your umask.
		570
		571
427	=item aio_rmdir $pathname, $callback->($status)	572	=item aio_rmdir $pathname, $callback->($status)
428		573
429	Asynchronously rmdir (delete) a directory and call the callback with the	574	Asynchronously rmdir (delete) a directory and call the callback with the
430	result code.	575	result code.
		576
431		577
432	=item aio_readdir $pathname, $callback->($entries)	578	=item aio_readdir $pathname, $callback->($entries)
433		579
434	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	580	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
435	directory (i.e. opendir + readdir + closedir). The entries will not be	581	directory (i.e. opendir + readdir + closedir). The entries will not be
436	sorted, and will B<NOT> include the C<.> and C<..> entries.	582	sorted, and will B<NOT> include the C<.> and C<..> entries.
437		583
438	The callback a single argument which is either C<undef> or an array-ref	584	The callback is passed a single argument which is either C<undef> or an
439	with the filenames.	585	array-ref with the filenames.
		586
		587
		588	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		589
		590	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		591	behaviour and output format. In case of an error, C<$entries> will be
		592	C<undef>.
		593
		594	The flags are a combination of the following constants, ORed together (the
		595	flags will also be passed to the callback, possibly modified):
		596
		597	=over 4
		598
		599	=item IO::AIO::READDIR_DENTS
		600
		601	When this flag is off, then the callback gets an arrayref with of names
		602	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		603	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		604	entry in more detail.
		605
		606	C<$name> is the name of the entry.
		607
		608	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		609
		610	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		611	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		612	C<IO::AIO::DT_WHT>.
		613
		614	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		615	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		616	scalars are read-only: you can not modify them.
		617
		618	C<$inode> is the inode number (which might not be exact on systems with 64
		619	bit inode numbers and 32 bit perls). This field has unspecified content on
		620	systems that do not deliver the inode information.
		621
		622	=item IO::AIO::READDIR_DIRS_FIRST
		623
		624	When this flag is set, then the names will be returned in an order where
		625	likely directories come first. This is useful when you need to quickly
		626	find directories, or you want to find all directories while avoiding to
		627	stat() each entry.
		628
		629	If the system returns type information in readdir, then this is used
		630	to find directories directly. Otherwise, likely directories are files
		631	beginning with ".", or otherwise files with no dots, of which files with
		632	short names are tried first.
		633
		634	=item IO::AIO::READDIR_STAT_ORDER
		635
		636	When this flag is set, then the names will be returned in an order
		637	suitable for stat()'ing each one. That is, when you plan to stat()
		638	all files in the given directory, then the returned order will likely
		639	be fastest.
		640
		641	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		642	the likely dirs come first, resulting in a less optimal stat order.
		643
		644	=item IO::AIO::READDIR_FOUND_UNKNOWN
		645
		646	This flag should not be set when calling C<aio_readdirx>. Instead, it
		647	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		648	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		649	C<$type>'s are known, which can be used to speed up some algorithms.
		650
		651	=back
		652
		653
		654	=item aio_load $path, $data, $callback->($status)
		655
		656	This is a composite request that tries to fully load the given file into
		657	memory. Status is the same as with aio_read.
		658
		659	=cut
		660
		661	sub aio_load($$;$) {
		662	my ($path, undef, $cb) = @_;
		663	my $data = \$_[1];
		664
		665	my $pri = aioreq_pri;
		666	my $grp = aio_group $cb;
		667
		668	aioreq_pri $pri;
		669	add $grp aio_open $path, O_RDONLY, 0, sub {
		670	my $fh = shift
		671	or return $grp->result (-1);
		672
		673	aioreq_pri $pri;
		674	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		675	$grp->result ($_[0]);
		676	};
		677	};
		678
		679	$grp
		680	}
440		681
441	=item aio_copy $srcpath, $dstpath, $callback->($status)	682	=item aio_copy $srcpath, $dstpath, $callback->($status)
442		683
443	Try to copy the I<file> (directories not supported as either source or	684	Try to copy the I<file> (directories not supported as either source or
444	destination) from C<$srcpath> to C<$dstpath> and call the callback with	685	destination) from C<$srcpath> to C<$dstpath> and call the callback with
445	the C<0> (error) or C<-1> ok.	686	a status of C<0> (ok) or C<-1> (error, see C<$!>).
446		687
447	This is a composite request that it creates the destination file with	688	This is a composite request that creates the destination file with
448	mode 0200 and copies the contents of the source file into it using	689	mode 0200 and copies the contents of the source file into it using
449	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	690	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
450	uid/gid, in that order.	691	uid/gid, in that order.
451		692
452	If an error occurs, the partial destination file will be unlinked, if	693	If an error occurs, the partial destination file will be unlinked, if
…		…
462	my $grp = aio_group $cb;	703	my $grp = aio_group $cb;
463		704
464	aioreq_pri $pri;	705	aioreq_pri $pri;
465	add $grp aio_open $src, O_RDONLY, 0, sub {	706	add $grp aio_open $src, O_RDONLY, 0, sub {
466	if (my $src_fh = $_[0]) {	707	if (my $src_fh = $_[0]) {
467	my @stat = stat $src_fh;	708	my @stat = stat $src_fh; # hmm, might block over nfs?
468		709
469	aioreq_pri $pri;	710	aioreq_pri $pri;
470	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	711	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
471	if (my $dst_fh = $_[0]) {	712	if (my $dst_fh = $_[0]) {
472	aioreq_pri $pri;	713	aioreq_pri $pri;
473	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	714	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
474	if ($_[0] == $stat[7]) {	715	if ($_[0] == $stat[7]) {
475	$grp->result (0);	716	$grp->result (0);
476	close $src_fh;	717	close $src_fh;
477		718
478	# those should not normally block. should. should.	719	my $ch = sub {
		720	aioreq_pri $pri;
		721	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		722	aioreq_pri $pri;
		723	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		724	aioreq_pri $pri;
		725	add $grp aio_close $dst_fh;
		726	}
		727	};
		728	};
		729
		730	aioreq_pri $pri;
		731	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		732	if ($_[0] < 0 && $! == ENOSYS) {
		733	aioreq_pri $pri;
479	utime $stat[8], $stat[9], $dst;	734	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
480	chmod $stat[2] & 07777, $dst_fh;	735	} else {
481	chown $stat[4], $stat[5], $dst_fh;	736	$ch->();
		737	}
482	close $dst_fh;	738	};
483	} else {	739	} else {
484	$grp->result (-1);	740	$grp->result (-1);
485	close $src_fh;	741	close $src_fh;
486	close $dst_fh;	742	close $dst_fh;
487		743
…		…
504		760
505	=item aio_move $srcpath, $dstpath, $callback->($status)	761	=item aio_move $srcpath, $dstpath, $callback->($status)
506		762
507	Try to move the I<file> (directories not supported as either source or	763	Try to move the I<file> (directories not supported as either source or
508	destination) from C<$srcpath> to C<$dstpath> and call the callback with	764	destination) from C<$srcpath> to C<$dstpath> and call the callback with
509	the C<0> (error) or C<-1> ok.	765	a status of C<0> (ok) or C<-1> (error, see C<$!>).
510		766
511	This is a composite request that tries to rename(2) the file first. If	767	This is a composite request that tries to rename(2) the file first; if
512	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	768	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
513	that is successful, unlinking the C<$srcpath>.	769	that is successful, unlinks the C<$srcpath>.
514		770
515	=cut	771	=cut
516		772
517	sub aio_move($$;$) {	773	sub aio_move($$;$) {
518	my ($src, $dst, $cb) = @_;	774	my ($src, $dst, $cb) = @_;
…		…
565		821
566	Implementation notes.	822	Implementation notes.
567		823
568	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	824	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
569		825
		826	If readdir returns file type information, then this is used directly to
		827	find directories.
		828
570	After reading the directory, the modification time, size etc. of the	829	Otherwise, after reading the directory, the modification time, size etc.
571	directory before and after the readdir is checked, and if they match (and	830	of the directory before and after the readdir is checked, and if they
572	isn't the current time), the link count will be used to decide how many	831	match (and isn't the current time), the link count will be used to decide
573	entries are directories (if >= 2). Otherwise, no knowledge of the number	832	how many entries are directories (if >= 2). Otherwise, no knowledge of the
574	of subdirectories will be assumed.	833	number of subdirectories will be assumed.
575		834
576	Then entries will be sorted into likely directories (everything without	835	Then entries will be sorted into likely directories a non-initial dot
577	a non-initial dot currently) and likely non-directories (everything	836	currently) and likely non-directories (see C<aio_readdirx>). Then every
578	else). Then every entry plus an appended C</.> will be C<stat>'ed,	837	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
579	likely directories first. If that succeeds, it assumes that the entry	838	in order of their inode numbers. If that succeeds, it assumes that the
580	is a directory or a symlink to directory (which will be checked	839	entry is a directory or a symlink to directory (which will be checked
581	seperately). This is often faster than stat'ing the entry itself because	840	seperately). This is often faster than stat'ing the entry itself because
582	filesystems might detect the type of the entry without reading the inode	841	filesystems might detect the type of the entry without reading the inode
583	data (e.g. ext2fs filetype feature).	842	data (e.g. ext2fs filetype feature), even on systems that cannot return
		843	the filetype information on readdir.
584		844
585	If the known number of directories (link count - 2) has been reached, the	845	If the known number of directories (link count - 2) has been reached, the
586	rest of the entries is assumed to be non-directories.	846	rest of the entries is assumed to be non-directories.
587		847
588	This only works with certainty on POSIX (= UNIX) filesystems, which	848	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
592	as those tend to return 0 or 1 as link counts, which disables the	852	as those tend to return 0 or 1 as link counts, which disables the
593	directory counting heuristic.	853	directory counting heuristic.
594		854
595	=cut	855	=cut
596		856
597	sub aio_scandir($$$) {	857	sub aio_scandir($$;$) {
598	my ($path, $maxreq, $cb) = @_;	858	my ($path, $maxreq, $cb) = @_;
599		859
600	my $pri = aioreq_pri;	860	my $pri = aioreq_pri;
601		861
602	my $grp = aio_group $cb;	862	my $grp = aio_group $cb;
…		…
610	my $now = time;	870	my $now = time;
611	my $hash1 = join ":", (stat _)[0,1,3,7,9];	871	my $hash1 = join ":", (stat _)[0,1,3,7,9];
612		872
613	# read the directory entries	873	# read the directory entries
614	aioreq_pri $pri;	874	aioreq_pri $pri;
615	add $grp aio_readdir $path, sub {	875	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
616	my $entries = shift	876	my $entries = shift
617	or return $grp->result ();	877	or return $grp->result ();
618		878
619	# stat the dir another time	879	# stat the dir another time
620	aioreq_pri $pri;	880	aioreq_pri $pri;
…		…
626	# take the slow route if anything looks fishy	886	# take the slow route if anything looks fishy
627	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	887	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
628	$ndirs = -1;	888	$ndirs = -1;
629	} else {	889	} else {
630	# if nlink == 2, we are finished	890	# if nlink == 2, we are finished
631	# on non-posix-fs's, we rely on nlink < 2	891	# for non-posix-fs's, we rely on nlink < 2
632	$ndirs = (stat _)[3] - 2	892	$ndirs = (stat _)[3] - 2
633	or return $grp->result ([], $entries);	893	or return $grp->result ([], $entries);
634	}	894	}
635		895
636	# sort into likely dirs and likely nondirs
637	# dirs == files without ".", short entries first
638	$entries = [map $_->[0],
639	sort { $b->[1] cmp $a->[1] }
640	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
641	@$entries];
642
643	my (@dirs, @nondirs);	896	my (@dirs, @nondirs);
644		897
645	my $statgrp = add $grp aio_group sub {	898	my $statgrp = add $grp aio_group sub {
646	$grp->result (\@dirs, \@nondirs);	899	$grp->result (\@dirs, \@nondirs);
647	};	900	};
648		901
649	limit $statgrp $maxreq;	902	limit $statgrp $maxreq;
650	feed $statgrp sub {	903	feed $statgrp sub {
651	return unless @$entries;	904	return unless @$entries;
652	my $entry = pop @$entries;	905	my $entry = shift @$entries;
653		906
654	aioreq_pri $pri;	907	aioreq_pri $pri;
655	add $statgrp aio_stat "$path/$entry/.", sub {	908	add $statgrp aio_stat "$path/$entry/.", sub {
656	if ($_[0] < 0) {	909	if ($_[0] < 0) {
657	push @nondirs, $entry;	910	push @nondirs, $entry;
…		…
678	};	931	};
679		932
680	$grp	933	$grp
681	}	934	}
682		935
		936	=item aio_rmtree $path, $callback->($status)
		937
		938	Delete a directory tree starting (and including) C<$path>, return the
		939	status of the final C<rmdir> only. This is a composite request that
		940	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		941	everything else.
		942
		943	=cut
		944
		945	sub aio_rmtree;
		946	sub aio_rmtree($;$) {
		947	my ($path, $cb) = @_;
		948
		949	my $pri = aioreq_pri;
		950	my $grp = aio_group $cb;
		951
		952	aioreq_pri $pri;
		953	add $grp aio_scandir $path, 0, sub {
		954	my ($dirs, $nondirs) = @_;
		955
		956	my $dirgrp = aio_group sub {
		957	add $grp aio_rmdir $path, sub {
		958	$grp->result ($_[0]);
		959	};
		960	};
		961
		962	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		963	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		964
		965	add $grp $dirgrp;
		966	};
		967
		968	$grp
		969	}
		970
		971	=item aio_sync $callback->($status)
		972
		973	Asynchronously call sync and call the callback when finished.
		974
683	=item aio_fsync $fh, $callback->($status)	975	=item aio_fsync $fh, $callback->($status)
684		976
685	Asynchronously call fsync on the given filehandle and call the callback	977	Asynchronously call fsync on the given filehandle and call the callback
686	with the fsync result code.	978	with the fsync result code.
687		979
…		…
690	Asynchronously call fdatasync on the given filehandle and call the	982	Asynchronously call fdatasync on the given filehandle and call the
691	callback with the fdatasync result code.	983	callback with the fdatasync result code.
692		984
693	If this call isn't available because your OS lacks it or it couldn't be	985	If this call isn't available because your OS lacks it or it couldn't be
694	detected, it will be emulated by calling C<fsync> instead.	986	detected, it will be emulated by calling C<fsync> instead.
		987
		988	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		989
		990	Sync the data portion of the file specified by C<$offset> and C<$length>
		991	to disk (but NOT the metadata), by calling the Linux-specific
		992	sync_file_range call. If sync_file_range is not available or it returns
		993	ENOSYS, then fdatasync or fsync is being substituted.
		994
		995	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		996	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		997	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		998	manpage for details.
		999
		1000	=item aio_pathsync $path, $callback->($status)
		1001
		1002	This request tries to open, fsync and close the given path. This is a
		1003	composite request intended to sync directories after directory operations
		1004	(E.g. rename). This might not work on all operating systems or have any
		1005	specific effect, but usually it makes sure that directory changes get
		1006	written to disc. It works for anything that can be opened for read-only,
		1007	not just directories.
		1008
		1009	Future versions of this function might fall back to other methods when
		1010	C<fsync> on the directory fails (such as calling C<sync>).
		1011
		1012	Passes C<0> when everything went ok, and C<-1> on error.
		1013
		1014	=cut
		1015
		1016	sub aio_pathsync($;$) {
		1017	my ($path, $cb) = @_;
		1018
		1019	my $pri = aioreq_pri;
		1020	my $grp = aio_group $cb;
		1021
		1022	aioreq_pri $pri;
		1023	add $grp aio_open $path, O_RDONLY, 0, sub {
		1024	my ($fh) = @_;
		1025	if ($fh) {
		1026	aioreq_pri $pri;
		1027	add $grp aio_fsync $fh, sub {
		1028	$grp->result ($_[0]);
		1029
		1030	aioreq_pri $pri;
		1031	add $grp aio_close $fh;
		1032	};
		1033	} else {
		1034	$grp->result (-1);
		1035	}
		1036	};
		1037
		1038	$grp
		1039	}
		1040
		1041	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1042
		1043	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1044	scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note
		1045	that the scalar must only be modified in-place while an aio operation is
		1046	pending on it).
		1047
		1048	It calls the C<msync> function of your OS, if available, with the memory
		1049	area starting at C<$offset> in the string and ending C<$length> bytes
		1050	later. If C<$length> is negative, counts from the end, and if C<$length>
		1051	is C<undef>, then it goes till the end of the string. The flags can be
		1052	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1053	C<IO::AIO::MS_SYNC>.
		1054
		1055	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1056
		1057	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1058	scalars.
		1059
		1060	It touches (reads or writes) all memory pages in the specified
		1061	range inside the scalar. All caveats and parameters are the same
		1062	as for C<aio_msync>, above, except for flags, which must be either
		1063	C<0> (which reads all pages and ensures they are instantiated) or
		1064	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1065	writing an octet from it, which dirties the page).
695		1066
696	=item aio_group $callback->(...)	1067	=item aio_group $callback->(...)
697		1068
698	This is a very special aio request: Instead of doing something, it is a	1069	This is a very special aio request: Instead of doing something, it is a
699	container for other aio requests, which is useful if you want to bundle	1070	container for other aio requests, which is useful if you want to bundle
…		…
749	=item cancel $req	1120	=item cancel $req
750		1121
751	Cancels the request, if possible. Has the effect of skipping execution	1122	Cancels the request, if possible. Has the effect of skipping execution
752	when entering the B<execute> state and skipping calling the callback when	1123	when entering the B<execute> state and skipping calling the callback when
753	entering the the B<result> state, but will leave the request otherwise	1124	entering the the B<result> state, but will leave the request otherwise
754	untouched. That means that requests that currently execute will not be	1125	untouched (with the exception of readdir). That means that requests that
755	stopped and resources held by the request will not be freed prematurely.	1126	currently execute will not be stopped and resources held by the request
		1127	will not be freed prematurely.
756		1128
757	=item cb $req $callback->(...)	1129	=item cb $req $callback->(...)
758		1130
759	Replace (or simply set) the callback registered to the request.	1131	Replace (or simply set) the callback registered to the request.
760		1132
…		…
811	Their lifetime, simplified, looks like this: when they are empty, they	1183	Their lifetime, simplified, looks like this: when they are empty, they
812	will finish very quickly. If they contain only requests that are in the	1184	will finish very quickly. If they contain only requests that are in the
813	C<done> state, they will also finish. Otherwise they will continue to	1185	C<done> state, they will also finish. Otherwise they will continue to
814	exist.	1186	exist.
815		1187
816	That means after creating a group you have some time to add requests. And	1188	That means after creating a group you have some time to add requests
817	in the callbacks of those requests, you can add further requests to the	1189	(precisely before the callback has been invoked, which is only done within
818	group. And only when all those requests have finished will the the group	1190	the C<poll_cb>). And in the callbacks of those requests, you can add
819	itself finish.	1191	further requests to the group. And only when all those requests have
		1192	finished will the the group itself finish.
820		1193
821	=over 4	1194	=over 4
822		1195
823	=item add $grp ...	1196	=item add $grp ...
824		1197
…		…
833	=item $grp->cancel_subs	1206	=item $grp->cancel_subs
834		1207
835	Cancel all subrequests and clears any feeder, but not the group request	1208	Cancel all subrequests and clears any feeder, but not the group request
836	itself. Useful when you queued a lot of events but got a result early.	1209	itself. Useful when you queued a lot of events but got a result early.
837		1210
		1211	The group request will finish normally (you cannot add requests to the
		1212	group).
		1213
838	=item $grp->result (...)	1214	=item $grp->result (...)
839		1215
840	Set the result value(s) that will be passed to the group callback when all	1216	Set the result value(s) that will be passed to the group callback when all
841	subrequests have finished and set thre groups errno to the current value	1217	subrequests have finished and set the groups errno to the current value
842	of errno (just like calling C<errno> without an error number). By default,	1218	of errno (just like calling C<errno> without an error number). By default,
843	no argument will be passed and errno is zero.	1219	no argument will be passed and errno is zero.
844		1220
845	=item $grp->errno ([$errno])	1221	=item $grp->errno ([$errno])
846		1222
…		…
857	=item feed $grp $callback->($grp)	1233	=item feed $grp $callback->($grp)
858		1234
859	Sets a feeder/generator on this group: every group can have an attached	1235	Sets a feeder/generator on this group: every group can have an attached
860	generator that generates requests if idle. The idea behind this is that,	1236	generator that generates requests if idle. The idea behind this is that,
861	although you could just queue as many requests as you want in a group,	1237	although you could just queue as many requests as you want in a group,
862	this might starve other requests for a potentially long time. For	1238	this might starve other requests for a potentially long time. For example,
863	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1239	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
864	requests, delaying any later requests for a long time.	1240	delaying any later requests for a long time.
865		1241
866	To avoid this, and allow incremental generation of requests, you can	1242	To avoid this, and allow incremental generation of requests, you can
867	instead a group and set a feeder on it that generates those requests. The	1243	instead a group and set a feeder on it that generates those requests. The
868	feed callback will be called whenever there are few enough (see C<limit>,	1244	feed callback will be called whenever there are few enough (see C<limit>,
869	below) requests active in the group itself and is expected to queue more	1245	below) requests active in the group itself and is expected to queue more
…		…
873	not impose any limits).	1249	not impose any limits).
874		1250
875	If the feed does not queue more requests when called, it will be	1251	If the feed does not queue more requests when called, it will be
876	automatically removed from the group.	1252	automatically removed from the group.
877		1253
878	If the feed limit is C<0>, it will be set to C<2> automatically.	1254	If the feed limit is C<0> when this method is called, it will be set to
		1255	C<2> automatically.
879		1256
880	Example:	1257	Example:
881		1258
882	# stat all files in @files, but only ever use four aio requests concurrently:	1259	# stat all files in @files, but only ever use four aio requests concurrently:
883		1260
…		…
895	Sets the feeder limit for the group: The feeder will be called whenever	1272	Sets the feeder limit for the group: The feeder will be called whenever
896	the group contains less than this many requests.	1273	the group contains less than this many requests.
897		1274
898	Setting the limit to C<0> will pause the feeding process.	1275	Setting the limit to C<0> will pause the feeding process.
899		1276
		1277	The default value for the limit is C<0>, but note that setting a feeder
		1278	automatically bumps it up to C<2>.
		1279
900	=back	1280	=back
901		1281
902	=head2 SUPPORT FUNCTIONS	1282	=head2 SUPPORT FUNCTIONS
903		1283
904	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1284	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
906	=over 4	1286	=over 4
907		1287
908	=item $fileno = IO::AIO::poll_fileno	1288	=item $fileno = IO::AIO::poll_fileno
909		1289
910	Return the I<request result pipe file descriptor>. This filehandle must be	1290	Return the I<request result pipe file descriptor>. This filehandle must be
911	polled for reading by some mechanism outside this module (e.g. Event or	1291	polled for reading by some mechanism outside this module (e.g. EV, Glib,
912	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1292	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
913	to call C<poll_cb> to check the results.	1293	you have to call C<poll_cb> to check the results.
914		1294
915	See C<poll_cb> for an example.	1295	See C<poll_cb> for an example.
916		1296
917	=item IO::AIO::poll_cb	1297	=item IO::AIO::poll_cb
918		1298
919	Process some outstanding events on the result pipe. You have to call this	1299	Process some outstanding events on the result pipe. You have to call this
920	regularly. Returns the number of events processed. Returns immediately	1300	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1301	returned earlier for whatever reason. Returns immediately when no events
921	when no events are outstanding. The amount of events processed depends on	1302	are outstanding. The amount of events processed depends on the settings of
922	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1303	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
923		1304
924	If not all requests were processed for whatever reason, the filehandle	1305	If not all requests were processed for whatever reason, the filehandle
925	will still be ready when C<poll_cb> returns.	1306	will still be ready when C<poll_cb> returns, so normally you don't have to
		1307	do anything special to have it called later.
926		1308
927	Example: Install an Event watcher that automatically calls	1309	Example: Install an Event watcher that automatically calls
928	IO::AIO::poll_cb with high priority:	1310	IO::AIO::poll_cb with high priority (more examples can be found in the
		1311	SYNOPSIS section, at the top of this document):
929		1312
930	Event->io (fd => IO::AIO::poll_fileno,	1313	Event->io (fd => IO::AIO::poll_fileno,
931	poll => 'r', async => 1,	1314	poll => 'r', async => 1,
932	cb => \&IO::AIO::poll_cb);	1315	cb => \&IO::AIO::poll_cb);
933		1316
…		…
939	that are being processed by C<IO::AIO::poll_cb> in one call, respectively	1322	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
940	the maximum amount of time (default C<0>, meaning infinity) spent in	1323	the maximum amount of time (default C<0>, meaning infinity) spent in
941	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount	1324	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
942	of time C<poll_cb> is allowed to use).	1325	of time C<poll_cb> is allowed to use).
943		1326
		1327	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1328	syscall per request processed, which is not normally a problem unless your
		1329	callbacks are really really fast or your OS is really really slow (I am
		1330	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1331
944	Setting these is useful if you want to ensure some level of	1332	Setting these is useful if you want to ensure some level of
945	interactiveness when perl is not fast enough to process all requests in	1333	interactiveness when perl is not fast enough to process all requests in
946	time.	1334	time.
947		1335
948	For interactive programs, values such as C<0.01> to C<0.1> should be fine.	1336	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
949		1337
950	Example: Install an Event watcher that automatically calls	1338	Example: Install an Event watcher that automatically calls
951	IO::AIO::poll_some with low priority, to ensure that other parts of the	1339	IO::AIO::poll_cb with low priority, to ensure that other parts of the
952	program get the CPU sometimes even under high AIO load.	1340	program get the CPU sometimes even under high AIO load.
953		1341
954	# try not to spend much more than 0.1s in poll_cb	1342	# try not to spend much more than 0.1s in poll_cb
955	IO::AIO::max_poll_time 0.1;	1343	IO::AIO::max_poll_time 0.1;
956		1344
…		…
959	poll => 'r', nice => 1,	1347	poll => 'r', nice => 1,
960	cb => &IO::AIO::poll_cb);	1348	cb => &IO::AIO::poll_cb);
961		1349
962	=item IO::AIO::poll_wait	1350	=item IO::AIO::poll_wait
963		1351
		1352	If there are any outstanding requests and none of them in the result
964	Wait till the result filehandle becomes ready for reading (simply does a	1353	phase, wait till the result filehandle becomes ready for reading (simply
965	C<select> on the filehandle. This is useful if you want to synchronously	1354	does a C<select> on the filehandle. This is useful if you want to
966	wait for some requests to finish).	1355	synchronously wait for some requests to finish).
967		1356
968	See C<nreqs> for an example.	1357	See C<nreqs> for an example.
969		1358
970	=item IO::AIO::poll	1359	=item IO::AIO::poll
971		1360
972	Waits until some requests have been handled.	1361	Waits until some requests have been handled.
973		1362
		1363	Returns the number of requests processed, but is otherwise strictly
974	Strictly equivalent to:	1364	equivalent to:
975		1365
976	IO::AIO::poll_wait, IO::AIO::poll_cb	1366	IO::AIO::poll_wait, IO::AIO::poll_cb
977	if IO::AIO::nreqs;
978		1367
979	=item IO::AIO::flush	1368	=item IO::AIO::flush
980		1369
981	Wait till all outstanding AIO requests have been handled.	1370	Wait till all outstanding AIO requests have been handled.
982		1371
983	Strictly equivalent to:	1372	Strictly equivalent to:
984		1373
985	IO::AIO::poll_wait, IO::AIO::poll_cb	1374	IO::AIO::poll_wait, IO::AIO::poll_cb
986	while IO::AIO::nreqs;	1375	while IO::AIO::nreqs;
987		1376
		1377	=back
		1378
988	=head3 CONTROLLING THE NUMBER OF THREADS	1379	=head3 CONTROLLING THE NUMBER OF THREADS
		1380
		1381	=over
989		1382
990	=item IO::AIO::min_parallel $nthreads	1383	=item IO::AIO::min_parallel $nthreads
991		1384
992	Set the minimum number of AIO threads to C<$nthreads>. The current	1385	Set the minimum number of AIO threads to C<$nthreads>. The current
993	default is C<8>, which means eight asynchronous operations can execute	1386	default is C<8>, which means eight asynchronous operations can execute
…		…
1034		1427
1035	The default is probably ok in most situations, especially if thread	1428	The default is probably ok in most situations, especially if thread
1036	creation is fast. If thread creation is very slow on your system you might	1429	creation is fast. If thread creation is very slow on your system you might
1037	want to use larger values.	1430	want to use larger values.
1038		1431
1039	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1432	=item IO::AIO::max_outstanding $maxreqs
1040		1433
1041	This is a very bad function to use in interactive programs because it	1434	This is a very bad function to use in interactive programs because it
1042	blocks, and a bad way to reduce concurrency because it is inexact: Better	1435	blocks, and a bad way to reduce concurrency because it is inexact: Better
1043	use an C<aio_group> together with a feed callback.	1436	use an C<aio_group> together with a feed callback.
1044		1437
1045	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1438	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1046	to queue up more than this number of requests, the next call to the	1439	do queue up more than this number of requests, the next call to the
1047	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1440	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1048	function will block until the limit is no longer exceeded.	1441	function will block until the limit is no longer exceeded.
1049		1442
1050	The default value is very large, so there is no practical limit on the	1443	The default value is very large, so there is no practical limit on the
1051	number of outstanding requests.	1444	number of outstanding requests.
1052		1445
1053	You can still queue as many requests as you want. Therefore,	1446	You can still queue as many requests as you want. Therefore,
1054	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1447	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1055	as a stop gap to shield against fatal memory overflow (with large values).	1448	as a stop gap to shield against fatal memory overflow (with large values).
1056		1449
		1450	=back
		1451
1057	=head3 STATISTICAL INFORMATION	1452	=head3 STATISTICAL INFORMATION
		1453
		1454	=over
1058		1455
1059	=item IO::AIO::nreqs	1456	=item IO::AIO::nreqs
1060		1457
1061	Returns the number of requests currently in the ready, execute or pending	1458	Returns the number of requests currently in the ready, execute or pending
1062	states (i.e. for which their callback has not been invoked yet).	1459	states (i.e. for which their callback has not been invoked yet).
…		…
1076	Returns the number of requests currently in the pending state (executed,	1473	Returns the number of requests currently in the pending state (executed,
1077	but not yet processed by poll_cb).	1474	but not yet processed by poll_cb).
1078		1475
1079	=back	1476	=back
1080		1477
		1478	=head3 MISCELLANEOUS FUNCTIONS
		1479
		1480	IO::AIO implements some functions that might be useful, but are not
		1481	asynchronous.
		1482
		1483	=over 4
		1484
		1485	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1486
		1487	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1488	but is blocking (this makes most sense if you know the input data is
		1489	likely cached already and the output filehandle is set to non-blocking
		1490	operations).
		1491
		1492	Returns the number of bytes copied, or C<-1> on error.
		1493
		1494	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1495
		1496	Simply calls the C<posix_fadvise> function (see it's
		1497	manpage for details). The following advice constants are
		1498	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1499	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1500	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1501
		1502	On systems that do not implement C<posix_fadvise>, this function returns
		1503	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1504
		1505	=back
		1506
1081	=cut	1507	=cut
1082		1508
1083	# support function to convert a fd into a perl filehandle
1084	sub _fd2fh {
1085	return undef if $_[0] < 0;
1086
1087	# try to generate nice filehandles
1088	my $sym = "IO::AIO::fd#$_[0]";
1089	local *$sym;
1090
1091	open *$sym, "+<&=$_[0]" # usually works under any unix
1092	or open *$sym, "<&=$_[0]" # cygwin needs this
1093	or open *$sym, ">&=$_[0]" # or this
1094	or return undef;
1095
1096	*$sym
1097	}
1098
1099	min_parallel 8;	1509	min_parallel 8;
1100		1510
1101	END {	1511	END { flush }
1102	min_parallel 1;
1103	flush;
1104	};
1105		1512
1106	1;	1513	1;
1107		1514
1108	=head2 FORK BEHAVIOUR	1515	=head2 FORK BEHAVIOUR
1109		1516
…		…
1129	bytes of memory. In addition, stat requests need a stat buffer (possibly	1536	bytes of memory. In addition, stat requests need a stat buffer (possibly
1130	a few hundred bytes), readdir requires a result buffer and so on. Perl	1537	a few hundred bytes), readdir requires a result buffer and so on. Perl
1131	scalars and other data passed into aio requests will also be locked and	1538	scalars and other data passed into aio requests will also be locked and
1132	will consume memory till the request has entered the done state.	1539	will consume memory till the request has entered the done state.
1133		1540
1134	This is now awfully much, so queuing lots of requests is not usually a	1541	This is not awfully much, so queuing lots of requests is not usually a
1135	problem.	1542	problem.
1136		1543
1137	Per-thread usage:	1544	Per-thread usage:
1138		1545
1139	In the execution phase, some aio requests require more memory for	1546	In the execution phase, some aio requests require more memory for
…		…
1144		1551
1145	Known bugs will be fixed in the next release.	1552	Known bugs will be fixed in the next release.
1146		1553
1147	=head1 SEE ALSO	1554	=head1 SEE ALSO
1148		1555
1149	L<Coro::AIO>.	1556	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1557	more natural syntax.
1150		1558
1151	=head1 AUTHOR	1559	=head1 AUTHOR
1152		1560
1153	Marc Lehmann <schmorp@schmorp.de>	1561	Marc Lehmann <schmorp@schmorp.de>
1154	http://home.schmorp.de/	1562	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.88 by root, Sun Oct 29 01:50:29 2006 UTC vs. Revision 1.172 by root, Thu Jan 7 18:08:21 2010 UTC

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Revision 1.88 by root, Sun Oct 29 01:50:29 2006 UTC vs.
Revision 1.172 by root, Thu Jan 7 18:08:21 2010 UTC