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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.93 by root, Wed Nov 8 01:59:58 2006 UTC vs.
Revision 1.171 by root, Sat Jan 2 14:24:32 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 most of this works on all types of file descriptors (for example	70	While most of this works on all types of file descriptors (for
67	sockets), using these functions on file descriptors that support	71	example sockets), using these functions on file descriptors that
68	nonblocking operation (again, sockets, pipes etc.) is very inefficient or	72	support nonblocking operation (again, sockets, pipes etc.) is
69	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop	73	very inefficient. Use an event loop for that (such as the L<EV>
70	for that (such as the L<Event\|Event> module): IO::AIO will naturally fit	74	module): IO::AIO will naturally fit into such an event loop itself.
71	into such an event loop itself.
72		75
73	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
74	requests and signal their completion. You don't need thread support	77	requests and signal their completion. You don't need thread support
75	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
76	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
…		…
78	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
79	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
80	aio_write, so the remaining functionality would have to be implemented	83	aio_write, so the remaining functionality would have to be implemented
81	using threads anyway.	84	using threads anyway.
82		85
83	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,
84	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
85	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
86	never call C<poll_cb> (or other C<aio_> functions) recursively.	89	call C<poll_cb> (or other C<aio_> functions) recursively.
87		90
88	=head2 EXAMPLE	91	=head2 EXAMPLE
89		92
90	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
91	F</etc/passwd> asynchronously:	94	F</etc/passwd> asynchronously:
92		95
93	use Fcntl;	96	use Fcntl;
94	use Event;	97	use EV;
95	use IO::AIO;	98	use IO::AIO;
96		99
97	# register the IO::AIO callback with Event	100	# register the IO::AIO callback with EV
98	Event->io (fd => IO::AIO::poll_fileno,	101	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
99	poll => 'r',
100	cb => \&IO::AIO::poll_cb);
101		102
102	# queue the request to open /etc/passwd	103	# queue the request to open /etc/passwd
103	aio_open "/etc/passwd", O_RDONLY, 0, sub {	104	aio_open "/etc/passwd", O_RDONLY, 0, sub {
104	my $fh = $_[0]	105	my $fh = shift
105	or die "error while opening: $!";	106	or die "error while opening: $!";
106		107
107	# stat'ing filehandles is generally non-blocking	108	# stat'ing filehandles is generally non-blocking
108	my $size = -s $fh;	109	my $size = -s $fh;
109		110
…		…
117		118
118	# file contents now in $contents	119	# file contents now in $contents
119	print $contents;	120	print $contents;
120		121
121	# exit event loop and program	122	# exit event loop and program
122	Event::unloop;	123	EV::unloop;
123	};	124	};
124	};	125	};
125		126
126	# possibly queue up other requests, or open GUI windows,	127	# possibly queue up other requests, or open GUI windows,
127	# check for sockets etc. etc.	128	# check for sockets etc. etc.
128		129
129	# process events as long as there are some:	130	# process events as long as there are some:
130	Event::loop;	131	EV::loop;
131		132
132	=head1 REQUEST ANATOMY AND LIFETIME	133	=head1 REQUEST ANATOMY AND LIFETIME
133		134
134	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
135	directly visible to Perl.	136	directly visible to Perl.
…		…
183		184
184	=cut	185	=cut
185		186
186	package IO::AIO;	187	package IO::AIO;
187		188
188	no warnings;	189	use Carp ();
189	use strict 'vars';	190
		191	use common::sense;
190		192
191	use base 'Exporter';	193	use base 'Exporter';
192		194
193	BEGIN {	195	BEGIN {
194	our $VERSION = '2.2';	196	our $VERSION = '3.4';
195		197
196	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
197	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
198	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link	200	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
199	aio_move 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);
		206
200	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	207	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
201	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	208	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
202	min_parallel max_parallel max_idle	209	min_parallel max_parallel max_idle
203	nreqs nready npending nthreads	210	nreqs nready npending nthreads
204	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
205		215
206	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
207		217
208	require XSLoader;	218	require XSLoader;
209	XSLoader::load ("IO::AIO", $VERSION);	219	XSLoader::load ("IO::AIO", $VERSION);
…		…
216	All the C<aio_*> calls are more or less thin wrappers around the syscall	226	All the C<aio_*> calls are more or less thin wrappers around the syscall
217	with the same name (sans C<aio_>). The arguments are similar or identical,	227	with the same name (sans C<aio_>). The arguments are similar or identical,
218	and they all accept an additional (and optional) C<$callback> argument	228	and they all accept an additional (and optional) C<$callback> argument
219	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
220	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
221	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
222	syscall has been executed asynchronously.	232	syscall has been executed asynchronously.
223		233
224	All functions expecting a filehandle keep a copy of the filehandle	234	All functions expecting a filehandle keep a copy of the filehandle
225	internally until the request has finished.	235	internally until the request has finished.
226		236
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240	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
241	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)
242	use something else to ensure your scalar has the correct contents.	252	use something else to ensure your scalar has the correct contents.
243		253
244	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
245	handles correctly wether it is set or not.	255	handles correctly whether it is set or not.
246		256
247	=over 4	257	=over 4
248		258
249	=item $prev_pri = aioreq_pri [$pri]	259	=item $prev_pri = aioreq_pri [$pri]
250		260
…		…
270	aio_read $_[0], ..., sub {	280	aio_read $_[0], ..., sub {
271	...	281	...
272	};	282	};
273	};	283	};
274		284
		285
275	=item aioreq_nice $pri_adjust	286	=item aioreq_nice $pri_adjust
276		287
277	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
278	priority, so the effect is cumulative.	289	priority, so the effect is cumulative.
		290
279		291
280	=item aio_open $pathname, $flags, $mode, $callback->($fh)	292	=item aio_open $pathname, $flags, $mode, $callback->($fh)
281		293
282	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
283	created filehandle for the file.	295	created filehandle for the file.
…		…
289	list. They are the same as used by C<sysopen>.	301	list. They are the same as used by C<sysopen>.
290		302
291	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
292	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>,
293	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,
294	and C<0666> or C<0777> if you do).	306	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		307	by the umask in effect then the request is being executed, so better never
		308	change the umask.
295		309
296	Example:	310	Example:
297		311
298	aio_open "/etc/passwd", O_RDONLY, 0, sub {	312	aio_open "/etc/passwd", O_RDONLY, 0, sub {
299	if ($_[0]) {	313	if ($_[0]) {
…		…
302	} else {	316	} else {
303	die "open failed: $!\n";	317	die "open failed: $!\n";
304	}	318	}
305	};	319	};
306		320
		321
307	=item aio_close $fh, $callback->($status)	322	=item aio_close $fh, $callback->($status)
308		323
309	Asynchronously close a file and call the callback with the result	324	Asynchronously close a file and call the callback with the result
310	code. I<WARNING:> although accepted, you should not pass in a perl	325	code.
311	filehandle here, as perl will likely close the file descriptor another
312	time when the filehandle is destroyed. Normally, you can safely call perls
313	C<close> or just let filehandles go out of scope.
314		326
315	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
316	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
317		338
318	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	339	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
319		340
320	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	341	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
321		342
322	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
323	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<$dataoffset>
324	callback without the actual number of bytes read (or -1 on error, just	345	and calls the callback without the actual number of bytes read (or -1 on
325	like the syscall).	346	error, just like the syscall).
		347
		348	C<aio_read> will, like C<sysread>, shrink or grow the C<$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<$data>.
326		360
327	The C<$data> scalar I<MUST NOT> be modified in any way while the request	361	The C<$data> scalar I<MUST NOT> be modified in any way while the request
328	is outstanding. Modifying it can result in segfaults or WW3 (if the	362	is outstanding. Modifying it can result in segfaults or World War III (if
329	necessary/optional hardware is installed).	363	the necessary/optional hardware is installed).
330		364
331	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	365	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
332	offset C<0> within the scalar:	366	offset C<0> within the scalar:
333		367
334	aio_read $fh, 7, 15, $buffer, 0, sub {	368	aio_read $fh, 7, 15, $buffer, 0, sub {
335	$_[0] > 0 or die "read error: $!";	369	$_[0] > 0 or die "read error: $!";
336	print "read $_[0] bytes: <$buffer>\n";	370	print "read $_[0] bytes: <$buffer>\n";
337	};	371	};
		372
338		373
339	=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)
340		375
341	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
342	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
…		…
346		381
347	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
348	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
349	socket, and C<$in_fh> should refer to mmap'able file.	384	socket, and C<$in_fh> should refer to mmap'able file.
350		385
351	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>,
352	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
353	regardless of the limitations of the operating system.	389	filehandle regardless of the limitations of the operating system.
354		390
355	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
356	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
357	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
358	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
359	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
360	read.	396	read.
		397
361		398
362	=item aio_readahead $fh,$offset,$length, $callback->($retval)	399	=item aio_readahead $fh,$offset,$length, $callback->($retval)
363		400
364	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
365	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>
…		…
371	file. The current file offset of the file is left unchanged.	408	file. The current file offset of the file is left unchanged.
372		409
373	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
374	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.
375		412
		413
376	=item aio_stat $fh_or_path, $callback->($status)	414	=item aio_stat $fh_or_path, $callback->($status)
377		415
378	=item aio_lstat $fh, $callback->($status)	416	=item aio_lstat $fh, $callback->($status)
379		417
380	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
…		…
393	aio_stat "/etc/passwd", sub {	431	aio_stat "/etc/passwd", sub {
394	$_[0] and die "stat failed: $!";	432	$_[0] and die "stat failed: $!";
395	print "size is ", -s _, "\n";	433	print "size is ", -s _, "\n";
396	};	434	};
397		435
		436
		437	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		438
		439	Works like perl's C<utime> function (including the special case of $atime
		440	and $mtime being undef). Fractional times are supported if the underlying
		441	syscalls support them.
		442
		443	When called with a pathname, uses utimes(2) if available, otherwise
		444	utime(2). If called on a file descriptor, uses futimes(2) if available,
		445	otherwise returns ENOSYS, so this is not portable.
		446
		447	Examples:
		448
		449	# set atime and mtime to current time (basically touch(1)):
		450	aio_utime "path", undef, undef;
		451	# set atime to current time and mtime to beginning of the epoch:
		452	aio_utime "path", time, undef; # undef==0
		453
		454
		455	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		456
		457	Works like perl's C<chown> function, except that C<undef> for either $uid
		458	or $gid is being interpreted as "do not change" (but -1 can also be used).
		459
		460	Examples:
		461
		462	# same as "chown root path" in the shell:
		463	aio_chown "path", 0, -1;
		464	# same as above:
		465	aio_chown "path", 0, undef;
		466
		467
		468	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		469
		470	Works like truncate(2) or ftruncate(2).
		471
		472
		473	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		474
		475	Works like perl's C<chmod> function.
		476
		477
398	=item aio_unlink $pathname, $callback->($status)	478	=item aio_unlink $pathname, $callback->($status)
399		479
400	Asynchronously unlink (delete) a file and call the callback with the	480	Asynchronously unlink (delete) a file and call the callback with the
401	result code.	481	result code.
402		482
		483
403	=item aio_mknod $path, $mode, $dev, $callback->($status)	484	=item aio_mknod $path, $mode, $dev, $callback->($status)
404		485
405	[EXPERIMENTAL]	486	[EXPERIMENTAL]
406		487
407	Asynchronously create a device node (or fifo). See mknod(2).	488	Asynchronously create a device node (or fifo). See mknod(2).
408		489
409	The only (POSIX-) portable way of calling this function is:	490	The only (POSIX-) portable way of calling this function is:
410		491
411	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	492	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		493
412		494
413	=item aio_link $srcpath, $dstpath, $callback->($status)	495	=item aio_link $srcpath, $dstpath, $callback->($status)
414		496
415	Asynchronously create a new link to the existing object at C<$srcpath> at	497	Asynchronously create a new link to the existing object at C<$srcpath> at
416	the path C<$dstpath> and call the callback with the result code.	498	the path C<$dstpath> and call the callback with the result code.
417		499
		500
418	=item aio_symlink $srcpath, $dstpath, $callback->($status)	501	=item aio_symlink $srcpath, $dstpath, $callback->($status)
419		502
420	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	503	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
421	the path C<$dstpath> and call the callback with the result code.	504	the path C<$dstpath> and call the callback with the result code.
		505
422		506
423	=item aio_readlink $path, $callback->($link)	507	=item aio_readlink $path, $callback->($link)
424		508
425	Asynchronously read the symlink specified by C<$path> and pass it to	509	Asynchronously read the symlink specified by C<$path> and pass it to
426	the callback. If an error occurs, nothing or undef gets passed to the	510	the callback. If an error occurs, nothing or undef gets passed to the
427	callback.	511	callback.
428		512
		513
429	=item aio_rename $srcpath, $dstpath, $callback->($status)	514	=item aio_rename $srcpath, $dstpath, $callback->($status)
430		515
431	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	516	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
432	rename(2) and call the callback with the result code.	517	rename(2) and call the callback with the result code.
433		518
		519
		520	=item aio_mkdir $pathname, $mode, $callback->($status)
		521
		522	Asynchronously mkdir (create) a directory and call the callback with
		523	the result code. C<$mode> will be modified by the umask at the time the
		524	request is executed, so do not change your umask.
		525
		526
434	=item aio_rmdir $pathname, $callback->($status)	527	=item aio_rmdir $pathname, $callback->($status)
435		528
436	Asynchronously rmdir (delete) a directory and call the callback with the	529	Asynchronously rmdir (delete) a directory and call the callback with the
437	result code.	530	result code.
		531
438		532
439	=item aio_readdir $pathname, $callback->($entries)	533	=item aio_readdir $pathname, $callback->($entries)
440		534
441	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	535	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
442	directory (i.e. opendir + readdir + closedir). The entries will not be	536	directory (i.e. opendir + readdir + closedir). The entries will not be
443	sorted, and will B<NOT> include the C<.> and C<..> entries.	537	sorted, and will B<NOT> include the C<.> and C<..> entries.
444		538
445	The callback a single argument which is either C<undef> or an array-ref	539	The callback is passed a single argument which is either C<undef> or an
446	with the filenames.	540	array-ref with the filenames.
		541
		542
		543	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		544
		545	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		546	behaviour and output format. In case of an error, C<$entries> will be
		547	C<undef>.
		548
		549	The flags are a combination of the following constants, ORed together (the
		550	flags will also be passed to the callback, possibly modified):
		551
		552	=over 4
		553
		554	=item IO::AIO::READDIR_DENTS
		555
		556	When this flag is off, then the callback gets an arrayref with of names
		557	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		558	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		559	entry in more detail.
		560
		561	C<$name> is the name of the entry.
		562
		563	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		564
		565	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		566	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		567	C<IO::AIO::DT_WHT>.
		568
		569	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		570	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		571	scalars are read-only: you can not modify them.
		572
		573	C<$inode> is the inode number (which might not be exact on systems with 64
		574	bit inode numbers and 32 bit perls). This field has unspecified content on
		575	systems that do not deliver the inode information.
		576
		577	=item IO::AIO::READDIR_DIRS_FIRST
		578
		579	When this flag is set, then the names will be returned in an order where
		580	likely directories come first. This is useful when you need to quickly
		581	find directories, or you want to find all directories while avoiding to
		582	stat() each entry.
		583
		584	If the system returns type information in readdir, then this is used
		585	to find directories directly. Otherwise, likely directories are files
		586	beginning with ".", or otherwise files with no dots, of which files with
		587	short names are tried first.
		588
		589	=item IO::AIO::READDIR_STAT_ORDER
		590
		591	When this flag is set, then the names will be returned in an order
		592	suitable for stat()'ing each one. That is, when you plan to stat()
		593	all files in the given directory, then the returned order will likely
		594	be fastest.
		595
		596	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		597	the likely dirs come first, resulting in a less optimal stat order.
		598
		599	=item IO::AIO::READDIR_FOUND_UNKNOWN
		600
		601	This flag should not be set when calling C<aio_readdirx>. Instead, it
		602	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		603	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		604	C<$type>'s are known, which can be used to speed up some algorithms.
		605
		606	=back
		607
		608
		609	=item aio_load $path, $data, $callback->($status)
		610
		611	This is a composite request that tries to fully load the given file into
		612	memory. Status is the same as with aio_read.
		613
		614	=cut
		615
		616	sub aio_load($$;$) {
		617	my ($path, undef, $cb) = @_;
		618	my $data = \$_[1];
		619
		620	my $pri = aioreq_pri;
		621	my $grp = aio_group $cb;
		622
		623	aioreq_pri $pri;
		624	add $grp aio_open $path, O_RDONLY, 0, sub {
		625	my $fh = shift
		626	or return $grp->result (-1);
		627
		628	aioreq_pri $pri;
		629	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		630	$grp->result ($_[0]);
		631	};
		632	};
		633
		634	$grp
		635	}
447		636
448	=item aio_copy $srcpath, $dstpath, $callback->($status)	637	=item aio_copy $srcpath, $dstpath, $callback->($status)
449		638
450	Try to copy the I<file> (directories not supported as either source or	639	Try to copy the I<file> (directories not supported as either source or
451	destination) from C<$srcpath> to C<$dstpath> and call the callback with	640	destination) from C<$srcpath> to C<$dstpath> and call the callback with
452	the C<0> (error) or C<-1> ok.	641	a status of C<0> (ok) or C<-1> (error, see C<$!>).
453		642
454	This is a composite request that it creates the destination file with	643	This is a composite request that creates the destination file with
455	mode 0200 and copies the contents of the source file into it using	644	mode 0200 and copies the contents of the source file into it using
456	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	645	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
457	uid/gid, in that order.	646	uid/gid, in that order.
458		647
459	If an error occurs, the partial destination file will be unlinked, if	648	If an error occurs, the partial destination file will be unlinked, if
…		…
469	my $grp = aio_group $cb;	658	my $grp = aio_group $cb;
470		659
471	aioreq_pri $pri;	660	aioreq_pri $pri;
472	add $grp aio_open $src, O_RDONLY, 0, sub {	661	add $grp aio_open $src, O_RDONLY, 0, sub {
473	if (my $src_fh = $_[0]) {	662	if (my $src_fh = $_[0]) {
474	my @stat = stat $src_fh;	663	my @stat = stat $src_fh; # hmm, might block over nfs?
475		664
476	aioreq_pri $pri;	665	aioreq_pri $pri;
477	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	666	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
478	if (my $dst_fh = $_[0]) {	667	if (my $dst_fh = $_[0]) {
479	aioreq_pri $pri;	668	aioreq_pri $pri;
480	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	669	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
481	if ($_[0] == $stat[7]) {	670	if ($_[0] == $stat[7]) {
482	$grp->result (0);	671	$grp->result (0);
483	close $src_fh;	672	close $src_fh;
484		673
485	# those should not normally block. should. should.	674	my $ch = sub {
		675	aioreq_pri $pri;
		676	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		677	aioreq_pri $pri;
		678	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		679	aioreq_pri $pri;
		680	add $grp aio_close $dst_fh;
		681	}
		682	};
		683	};
		684
		685	aioreq_pri $pri;
		686	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		687	if ($_[0] < 0 && $! == ENOSYS) {
		688	aioreq_pri $pri;
486	utime $stat[8], $stat[9], $dst;	689	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
487	chmod $stat[2] & 07777, $dst_fh;	690	} else {
488	chown $stat[4], $stat[5], $dst_fh;	691	$ch->();
		692	}
489	close $dst_fh;	693	};
490	} else {	694	} else {
491	$grp->result (-1);	695	$grp->result (-1);
492	close $src_fh;	696	close $src_fh;
493	close $dst_fh;	697	close $dst_fh;
494		698
…		…
511		715
512	=item aio_move $srcpath, $dstpath, $callback->($status)	716	=item aio_move $srcpath, $dstpath, $callback->($status)
513		717
514	Try to move the I<file> (directories not supported as either source or	718	Try to move the I<file> (directories not supported as either source or
515	destination) from C<$srcpath> to C<$dstpath> and call the callback with	719	destination) from C<$srcpath> to C<$dstpath> and call the callback with
516	the C<0> (error) or C<-1> ok.	720	a status of C<0> (ok) or C<-1> (error, see C<$!>).
517		721
518	This is a composite request that tries to rename(2) the file first. If	722	This is a composite request that tries to rename(2) the file first; if
519	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	723	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
520	that is successful, unlinking the C<$srcpath>.	724	that is successful, unlinks the C<$srcpath>.
521		725
522	=cut	726	=cut
523		727
524	sub aio_move($$;$) {	728	sub aio_move($$;$) {
525	my ($src, $dst, $cb) = @_;	729	my ($src, $dst, $cb) = @_;
…		…
572		776
573	Implementation notes.	777	Implementation notes.
574		778
575	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	779	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
576		780
		781	If readdir returns file type information, then this is used directly to
		782	find directories.
		783
577	After reading the directory, the modification time, size etc. of the	784	Otherwise, after reading the directory, the modification time, size etc.
578	directory before and after the readdir is checked, and if they match (and	785	of the directory before and after the readdir is checked, and if they
579	isn't the current time), the link count will be used to decide how many	786	match (and isn't the current time), the link count will be used to decide
580	entries are directories (if >= 2). Otherwise, no knowledge of the number	787	how many entries are directories (if >= 2). Otherwise, no knowledge of the
581	of subdirectories will be assumed.	788	number of subdirectories will be assumed.
582		789
583	Then entries will be sorted into likely directories (everything without	790	Then entries will be sorted into likely directories a non-initial dot
584	a non-initial dot currently) and likely non-directories (everything	791	currently) and likely non-directories (see C<aio_readdirx>). Then every
585	else). Then every entry plus an appended C</.> will be C<stat>'ed,	792	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
586	likely directories first. If that succeeds, it assumes that the entry	793	in order of their inode numbers. If that succeeds, it assumes that the
587	is a directory or a symlink to directory (which will be checked	794	entry is a directory or a symlink to directory (which will be checked
588	seperately). This is often faster than stat'ing the entry itself because	795	seperately). This is often faster than stat'ing the entry itself because
589	filesystems might detect the type of the entry without reading the inode	796	filesystems might detect the type of the entry without reading the inode
590	data (e.g. ext2fs filetype feature).	797	data (e.g. ext2fs filetype feature), even on systems that cannot return
		798	the filetype information on readdir.
591		799
592	If the known number of directories (link count - 2) has been reached, the	800	If the known number of directories (link count - 2) has been reached, the
593	rest of the entries is assumed to be non-directories.	801	rest of the entries is assumed to be non-directories.
594		802
595	This only works with certainty on POSIX (= UNIX) filesystems, which	803	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
599	as those tend to return 0 or 1 as link counts, which disables the	807	as those tend to return 0 or 1 as link counts, which disables the
600	directory counting heuristic.	808	directory counting heuristic.
601		809
602	=cut	810	=cut
603		811
604	sub aio_scandir($$$) {	812	sub aio_scandir($$;$) {
605	my ($path, $maxreq, $cb) = @_;	813	my ($path, $maxreq, $cb) = @_;
606		814
607	my $pri = aioreq_pri;	815	my $pri = aioreq_pri;
608		816
609	my $grp = aio_group $cb;	817	my $grp = aio_group $cb;
…		…
617	my $now = time;	825	my $now = time;
618	my $hash1 = join ":", (stat _)[0,1,3,7,9];	826	my $hash1 = join ":", (stat _)[0,1,3,7,9];
619		827
620	# read the directory entries	828	# read the directory entries
621	aioreq_pri $pri;	829	aioreq_pri $pri;
622	add $grp aio_readdir $path, sub {	830	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
623	my $entries = shift	831	my $entries = shift
624	or return $grp->result ();	832	or return $grp->result ();
625		833
626	# stat the dir another time	834	# stat the dir another time
627	aioreq_pri $pri;	835	aioreq_pri $pri;
…		…
633	# take the slow route if anything looks fishy	841	# take the slow route if anything looks fishy
634	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	842	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
635	$ndirs = -1;	843	$ndirs = -1;
636	} else {	844	} else {
637	# if nlink == 2, we are finished	845	# if nlink == 2, we are finished
638	# on non-posix-fs's, we rely on nlink < 2	846	# for non-posix-fs's, we rely on nlink < 2
639	$ndirs = (stat _)[3] - 2	847	$ndirs = (stat _)[3] - 2
640	or return $grp->result ([], $entries);	848	or return $grp->result ([], $entries);
641	}	849	}
642		850
643	# sort into likely dirs and likely nondirs
644	# dirs == files without ".", short entries first
645	$entries = [map $_->[0],
646	sort { $b->[1] cmp $a->[1] }
647	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
648	@$entries];
649
650	my (@dirs, @nondirs);	851	my (@dirs, @nondirs);
651		852
652	my $statgrp = add $grp aio_group sub {	853	my $statgrp = add $grp aio_group sub {
653	$grp->result (\@dirs, \@nondirs);	854	$grp->result (\@dirs, \@nondirs);
654	};	855	};
655		856
656	limit $statgrp $maxreq;	857	limit $statgrp $maxreq;
657	feed $statgrp sub {	858	feed $statgrp sub {
658	return unless @$entries;	859	return unless @$entries;
659	my $entry = pop @$entries;	860	my $entry = shift @$entries;
660		861
661	aioreq_pri $pri;	862	aioreq_pri $pri;
662	add $statgrp aio_stat "$path/$entry/.", sub {	863	add $statgrp aio_stat "$path/$entry/.", sub {
663	if ($_[0] < 0) {	864	if ($_[0] < 0) {
664	push @nondirs, $entry;	865	push @nondirs, $entry;
…		…
685	};	886	};
686		887
687	$grp	888	$grp
688	}	889	}
689		890
		891	=item aio_rmtree $path, $callback->($status)
		892
		893	Delete a directory tree starting (and including) C<$path>, return the
		894	status of the final C<rmdir> only. This is a composite request that
		895	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		896	everything else.
		897
		898	=cut
		899
		900	sub aio_rmtree;
		901	sub aio_rmtree($;$) {
		902	my ($path, $cb) = @_;
		903
		904	my $pri = aioreq_pri;
		905	my $grp = aio_group $cb;
		906
		907	aioreq_pri $pri;
		908	add $grp aio_scandir $path, 0, sub {
		909	my ($dirs, $nondirs) = @_;
		910
		911	my $dirgrp = aio_group sub {
		912	add $grp aio_rmdir $path, sub {
		913	$grp->result ($_[0]);
		914	};
		915	};
		916
		917	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		918	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		919
		920	add $grp $dirgrp;
		921	};
		922
		923	$grp
		924	}
		925
		926	=item aio_sync $callback->($status)
		927
		928	Asynchronously call sync and call the callback when finished.
		929
690	=item aio_fsync $fh, $callback->($status)	930	=item aio_fsync $fh, $callback->($status)
691		931
692	Asynchronously call fsync on the given filehandle and call the callback	932	Asynchronously call fsync on the given filehandle and call the callback
693	with the fsync result code.	933	with the fsync result code.
694		934
…		…
697	Asynchronously call fdatasync on the given filehandle and call the	937	Asynchronously call fdatasync on the given filehandle and call the
698	callback with the fdatasync result code.	938	callback with the fdatasync result code.
699		939
700	If this call isn't available because your OS lacks it or it couldn't be	940	If this call isn't available because your OS lacks it or it couldn't be
701	detected, it will be emulated by calling C<fsync> instead.	941	detected, it will be emulated by calling C<fsync> instead.
		942
		943	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		944
		945	Sync the data portion of the file specified by C<$offset> and C<$length>
		946	to disk (but NOT the metadata), by calling the Linux-specific
		947	sync_file_range call. If sync_file_range is not available or it returns
		948	ENOSYS, then fdatasync or fsync is being substituted.
		949
		950	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		951	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		952	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		953	manpage for details.
		954
		955	=item aio_pathsync $path, $callback->($status)
		956
		957	This request tries to open, fsync and close the given path. This is a
		958	composite request intended to sync directories after directory operations
		959	(E.g. rename). This might not work on all operating systems or have any
		960	specific effect, but usually it makes sure that directory changes get
		961	written to disc. It works for anything that can be opened for read-only,
		962	not just directories.
		963
		964	Future versions of this function might fall back to other methods when
		965	C<fsync> on the directory fails (such as calling C<sync>).
		966
		967	Passes C<0> when everything went ok, and C<-1> on error.
		968
		969	=cut
		970
		971	sub aio_pathsync($;$) {
		972	my ($path, $cb) = @_;
		973
		974	my $pri = aioreq_pri;
		975	my $grp = aio_group $cb;
		976
		977	aioreq_pri $pri;
		978	add $grp aio_open $path, O_RDONLY, 0, sub {
		979	my ($fh) = @_;
		980	if ($fh) {
		981	aioreq_pri $pri;
		982	add $grp aio_fsync $fh, sub {
		983	$grp->result ($_[0]);
		984
		985	aioreq_pri $pri;
		986	add $grp aio_close $fh;
		987	};
		988	} else {
		989	$grp->result (-1);
		990	}
		991	};
		992
		993	$grp
		994	}
		995
		996	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		997
		998	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		999	scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note
		1000	that the scalar must only be modified in-place while an aio operation is
		1001	pending on it).
		1002
		1003	It calls the C<msync> function of your OS, if available, with the memory
		1004	area starting at C<$offset> in the string and ending C<$length> bytes
		1005	later. If C<$length> is negative, counts from the end, and if C<$length>
		1006	is C<undef>, then it goes till the end of the string. The flags can be
		1007	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1008	C<IO::AIO::MS_SYNC>.
		1009
		1010	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1011
		1012	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1013	scalars.
		1014
		1015	It touches (reads or writes) all memory pages in the specified
		1016	range inside the scalar. All caveats and parameters are the same
		1017	as for C<aio_msync>, above, except for flags, which must be either
		1018	C<0> (which reads all pages and ensures they are instantiated) or
		1019	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1020	writing an octet from it, which dirties the page).
702		1021
703	=item aio_group $callback->(...)	1022	=item aio_group $callback->(...)
704		1023
705	This is a very special aio request: Instead of doing something, it is a	1024	This is a very special aio request: Instead of doing something, it is a
706	container for other aio requests, which is useful if you want to bundle	1025	container for other aio requests, which is useful if you want to bundle
…		…
756	=item cancel $req	1075	=item cancel $req
757		1076
758	Cancels the request, if possible. Has the effect of skipping execution	1077	Cancels the request, if possible. Has the effect of skipping execution
759	when entering the B<execute> state and skipping calling the callback when	1078	when entering the B<execute> state and skipping calling the callback when
760	entering the the B<result> state, but will leave the request otherwise	1079	entering the the B<result> state, but will leave the request otherwise
761	untouched. That means that requests that currently execute will not be	1080	untouched (with the exception of readdir). That means that requests that
762	stopped and resources held by the request will not be freed prematurely.	1081	currently execute will not be stopped and resources held by the request
		1082	will not be freed prematurely.
763		1083
764	=item cb $req $callback->(...)	1084	=item cb $req $callback->(...)
765		1085
766	Replace (or simply set) the callback registered to the request.	1086	Replace (or simply set) the callback registered to the request.
767		1087
…		…
818	Their lifetime, simplified, looks like this: when they are empty, they	1138	Their lifetime, simplified, looks like this: when they are empty, they
819	will finish very quickly. If they contain only requests that are in the	1139	will finish very quickly. If they contain only requests that are in the
820	C<done> state, they will also finish. Otherwise they will continue to	1140	C<done> state, they will also finish. Otherwise they will continue to
821	exist.	1141	exist.
822		1142
823	That means after creating a group you have some time to add requests. And	1143	That means after creating a group you have some time to add requests
824	in the callbacks of those requests, you can add further requests to the	1144	(precisely before the callback has been invoked, which is only done within
825	group. And only when all those requests have finished will the the group	1145	the C<poll_cb>). And in the callbacks of those requests, you can add
826	itself finish.	1146	further requests to the group. And only when all those requests have
		1147	finished will the the group itself finish.
827		1148
828	=over 4	1149	=over 4
829		1150
830	=item add $grp ...	1151	=item add $grp ...
831		1152
…		…
840	=item $grp->cancel_subs	1161	=item $grp->cancel_subs
841		1162
842	Cancel all subrequests and clears any feeder, but not the group request	1163	Cancel all subrequests and clears any feeder, but not the group request
843	itself. Useful when you queued a lot of events but got a result early.	1164	itself. Useful when you queued a lot of events but got a result early.
844		1165
		1166	The group request will finish normally (you cannot add requests to the
		1167	group).
		1168
845	=item $grp->result (...)	1169	=item $grp->result (...)
846		1170
847	Set the result value(s) that will be passed to the group callback when all	1171	Set the result value(s) that will be passed to the group callback when all
848	subrequests have finished and set thre groups errno to the current value	1172	subrequests have finished and set the groups errno to the current value
849	of errno (just like calling C<errno> without an error number). By default,	1173	of errno (just like calling C<errno> without an error number). By default,
850	no argument will be passed and errno is zero.	1174	no argument will be passed and errno is zero.
851		1175
852	=item $grp->errno ([$errno])	1176	=item $grp->errno ([$errno])
853		1177
…		…
864	=item feed $grp $callback->($grp)	1188	=item feed $grp $callback->($grp)
865		1189
866	Sets a feeder/generator on this group: every group can have an attached	1190	Sets a feeder/generator on this group: every group can have an attached
867	generator that generates requests if idle. The idea behind this is that,	1191	generator that generates requests if idle. The idea behind this is that,
868	although you could just queue as many requests as you want in a group,	1192	although you could just queue as many requests as you want in a group,
869	this might starve other requests for a potentially long time. For	1193	this might starve other requests for a potentially long time. For example,
870	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1194	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
871	requests, delaying any later requests for a long time.	1195	delaying any later requests for a long time.
872		1196
873	To avoid this, and allow incremental generation of requests, you can	1197	To avoid this, and allow incremental generation of requests, you can
874	instead a group and set a feeder on it that generates those requests. The	1198	instead a group and set a feeder on it that generates those requests. The
875	feed callback will be called whenever there are few enough (see C<limit>,	1199	feed callback will be called whenever there are few enough (see C<limit>,
876	below) requests active in the group itself and is expected to queue more	1200	below) requests active in the group itself and is expected to queue more
…		…
880	not impose any limits).	1204	not impose any limits).
881		1205
882	If the feed does not queue more requests when called, it will be	1206	If the feed does not queue more requests when called, it will be
883	automatically removed from the group.	1207	automatically removed from the group.
884		1208
885	If the feed limit is C<0>, it will be set to C<2> automatically.	1209	If the feed limit is C<0> when this method is called, it will be set to
		1210	C<2> automatically.
886		1211
887	Example:	1212	Example:
888		1213
889	# stat all files in @files, but only ever use four aio requests concurrently:	1214	# stat all files in @files, but only ever use four aio requests concurrently:
890		1215
…		…
902	Sets the feeder limit for the group: The feeder will be called whenever	1227	Sets the feeder limit for the group: The feeder will be called whenever
903	the group contains less than this many requests.	1228	the group contains less than this many requests.
904		1229
905	Setting the limit to C<0> will pause the feeding process.	1230	Setting the limit to C<0> will pause the feeding process.
906		1231
		1232	The default value for the limit is C<0>, but note that setting a feeder
		1233	automatically bumps it up to C<2>.
		1234
907	=back	1235	=back
908		1236
909	=head2 SUPPORT FUNCTIONS	1237	=head2 SUPPORT FUNCTIONS
910		1238
911	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1239	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
913	=over 4	1241	=over 4
914		1242
915	=item $fileno = IO::AIO::poll_fileno	1243	=item $fileno = IO::AIO::poll_fileno
916		1244
917	Return the I<request result pipe file descriptor>. This filehandle must be	1245	Return the I<request result pipe file descriptor>. This filehandle must be
918	polled for reading by some mechanism outside this module (e.g. Event or	1246	polled for reading by some mechanism outside this module (e.g. EV, Glib,
919	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1247	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
920	to call C<poll_cb> to check the results.	1248	you have to call C<poll_cb> to check the results.
921		1249
922	See C<poll_cb> for an example.	1250	See C<poll_cb> for an example.
923		1251
924	=item IO::AIO::poll_cb	1252	=item IO::AIO::poll_cb
925		1253
926	Process some outstanding events on the result pipe. You have to call this	1254	Process some outstanding events on the result pipe. You have to call this
927	regularly. Returns the number of events processed. Returns immediately	1255	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1256	returned earlier for whatever reason. Returns immediately when no events
928	when no events are outstanding. The amount of events processed depends on	1257	are outstanding. The amount of events processed depends on the settings of
929	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1258	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
930		1259
931	If not all requests were processed for whatever reason, the filehandle	1260	If not all requests were processed for whatever reason, the filehandle
932	will still be ready when C<poll_cb> returns.	1261	will still be ready when C<poll_cb> returns, so normally you don't have to
		1262	do anything special to have it called later.
933		1263
934	Example: Install an Event watcher that automatically calls	1264	Example: Install an Event watcher that automatically calls
935	IO::AIO::poll_cb with high priority:	1265	IO::AIO::poll_cb with high priority (more examples can be found in the
		1266	SYNOPSIS section, at the top of this document):
936		1267
937	Event->io (fd => IO::AIO::poll_fileno,	1268	Event->io (fd => IO::AIO::poll_fileno,
938	poll => 'r', async => 1,	1269	poll => 'r', async => 1,
939	cb => \&IO::AIO::poll_cb);	1270	cb => \&IO::AIO::poll_cb);
940		1271
…		…
996	Strictly equivalent to:	1327	Strictly equivalent to:
997		1328
998	IO::AIO::poll_wait, IO::AIO::poll_cb	1329	IO::AIO::poll_wait, IO::AIO::poll_cb
999	while IO::AIO::nreqs;	1330	while IO::AIO::nreqs;
1000		1331
		1332	=back
		1333
1001	=head3 CONTROLLING THE NUMBER OF THREADS	1334	=head3 CONTROLLING THE NUMBER OF THREADS
		1335
		1336	=over
1002		1337
1003	=item IO::AIO::min_parallel $nthreads	1338	=item IO::AIO::min_parallel $nthreads
1004		1339
1005	Set the minimum number of AIO threads to C<$nthreads>. The current	1340	Set the minimum number of AIO threads to C<$nthreads>. The current
1006	default is C<8>, which means eight asynchronous operations can execute	1341	default is C<8>, which means eight asynchronous operations can execute
…		…
1047		1382
1048	The default is probably ok in most situations, especially if thread	1383	The default is probably ok in most situations, especially if thread
1049	creation is fast. If thread creation is very slow on your system you might	1384	creation is fast. If thread creation is very slow on your system you might
1050	want to use larger values.	1385	want to use larger values.
1051		1386
1052	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1387	=item IO::AIO::max_outstanding $maxreqs
1053		1388
1054	This is a very bad function to use in interactive programs because it	1389	This is a very bad function to use in interactive programs because it
1055	blocks, and a bad way to reduce concurrency because it is inexact: Better	1390	blocks, and a bad way to reduce concurrency because it is inexact: Better
1056	use an C<aio_group> together with a feed callback.	1391	use an C<aio_group> together with a feed callback.
1057		1392
1058	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1393	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1059	to queue up more than this number of requests, the next call to the	1394	do queue up more than this number of requests, the next call to the
1060	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1395	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1061	function will block until the limit is no longer exceeded.	1396	function will block until the limit is no longer exceeded.
1062		1397
1063	The default value is very large, so there is no practical limit on the	1398	The default value is very large, so there is no practical limit on the
1064	number of outstanding requests.	1399	number of outstanding requests.
1065		1400
1066	You can still queue as many requests as you want. Therefore,	1401	You can still queue as many requests as you want. Therefore,
1067	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1402	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1068	as a stop gap to shield against fatal memory overflow (with large values).	1403	as a stop gap to shield against fatal memory overflow (with large values).
1069		1404
		1405	=back
		1406
1070	=head3 STATISTICAL INFORMATION	1407	=head3 STATISTICAL INFORMATION
		1408
		1409	=over
1071		1410
1072	=item IO::AIO::nreqs	1411	=item IO::AIO::nreqs
1073		1412
1074	Returns the number of requests currently in the ready, execute or pending	1413	Returns the number of requests currently in the ready, execute or pending
1075	states (i.e. for which their callback has not been invoked yet).	1414	states (i.e. for which their callback has not been invoked yet).
…		…
1089	Returns the number of requests currently in the pending state (executed,	1428	Returns the number of requests currently in the pending state (executed,
1090	but not yet processed by poll_cb).	1429	but not yet processed by poll_cb).
1091		1430
1092	=back	1431	=back
1093		1432
		1433	=head3 MISCELLANEOUS FUNCTIONS
		1434
		1435	IO::AIO implements some functions that might be useful, but are not
		1436	asynchronous.
		1437
		1438	=over 4
		1439
		1440	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1441
		1442	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1443	but is blocking (this makes most sense if you know the input data is
		1444	likely cached already and the output filehandle is set to non-blocking
		1445	operations).
		1446
		1447	Returns the number of bytes copied, or C<-1> on error.
		1448
		1449	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1450
		1451	Simply calls the C<posix_fadvise> function (see it's
		1452	manpage for details). The following advice constants are
		1453	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1454	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1455	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1456
		1457	On systems that do not implement C<posix_fadvise>, this function returns
		1458	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1459
		1460	=back
		1461
1094	=cut	1462	=cut
1095		1463
1096	# support function to convert a fd into a perl filehandle
1097	sub _fd2fh {
1098	return undef if $_[0] < 0;
1099
1100	# try to generate nice filehandles
1101	my $sym = "IO::AIO::fd#$_[0]";
1102	local *$sym;
1103
1104	open *$sym, "+<&=$_[0]" # usually works under any unix
1105	or open *$sym, "<&=$_[0]" # cygwin needs this
1106	or open *$sym, ">&=$_[0]" # or this
1107	or return undef;
1108
1109	*$sym
1110	}
1111
1112	min_parallel 8;	1464	min_parallel 8;
1113		1465
1114	END {	1466	END { flush }
1115	min_parallel 1;
1116	flush;
1117	};
1118		1467
1119	1;	1468	1;
1120		1469
1121	=head2 FORK BEHAVIOUR	1470	=head2 FORK BEHAVIOUR
1122		1471
…		…
1142	bytes of memory. In addition, stat requests need a stat buffer (possibly	1491	bytes of memory. In addition, stat requests need a stat buffer (possibly
1143	a few hundred bytes), readdir requires a result buffer and so on. Perl	1492	a few hundred bytes), readdir requires a result buffer and so on. Perl
1144	scalars and other data passed into aio requests will also be locked and	1493	scalars and other data passed into aio requests will also be locked and
1145	will consume memory till the request has entered the done state.	1494	will consume memory till the request has entered the done state.
1146		1495
1147	This is now awfully much, so queuing lots of requests is not usually a	1496	This is not awfully much, so queuing lots of requests is not usually a
1148	problem.	1497	problem.
1149		1498
1150	Per-thread usage:	1499	Per-thread usage:
1151		1500
1152	In the execution phase, some aio requests require more memory for	1501	In the execution phase, some aio requests require more memory for
…		…
1157		1506
1158	Known bugs will be fixed in the next release.	1507	Known bugs will be fixed in the next release.
1159		1508
1160	=head1 SEE ALSO	1509	=head1 SEE ALSO
1161		1510
1162	L<Coro::AIO>.	1511	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1512	more natural syntax.
1163		1513
1164	=head1 AUTHOR	1514	=head1 AUTHOR
1165		1515
1166	Marc Lehmann <schmorp@schmorp.de>	1516	Marc Lehmann <schmorp@schmorp.de>
1167	http://home.schmorp.de/	1517	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.93 by root, Wed Nov 8 01:59:58 2006 UTC vs. Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.93 by root, Wed Nov 8 01:59:58 2006 UTC vs.
Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC