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Revision 1.109 by root, Sun Jun 3 09:44:17 2007 UTC vs.
Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC

…		…
4		4
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", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51
52	=head1 DESCRIPTION	31	=head1 DESCRIPTION
53		32
54	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
55	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
56		36
57	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
58	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
59	will still block, but you can do something else in the meantime. This	39	will still block, but you can do something else in the meantime. This
60	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
64	on a RAID volume or over NFS when you do a number of stat operations	44	on a RAID volume or over NFS when you do a number of stat operations
65	concurrently.	45	concurrently.
66		46
67	While most of this works on all types of file descriptors (for	47	While most of this works on all types of file descriptors (for
68	example sockets), using these functions on file descriptors that	48	example sockets), using these functions on file descriptors that
69	support nonblocking operation (again, sockets, pipes etc.) is very	49	support nonblocking operation (again, sockets, pipes etc.) is
70	inefficient. Use an event loop for that (such as the L<Event|Event>	50	very inefficient. Use an event loop for that (such as the L<EV>
71	module): IO::AIO will naturally fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
72		52
73	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
74	requests and signal their completion. You don't need thread support	54	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	55	in perl, and the threads created by this module will not be visible
…		…
85	yourself, always call C<poll_cb> from within the same thread, or never	65	yourself, always call C<poll_cb> from within the same thread, or never
86	call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
87		67
88	=head2 EXAMPLE	68	=head2 EXAMPLE
89		69
90	This is a simple example that uses the Event module and loads	70	This is a simple example that uses the EV module and loads
91	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
92		72
93	use Fcntl;	73	use Fcntl;
94	use Event;	74	use EV;
95	use IO::AIO;	75	use IO::AIO;
96		76
97	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
98	Event->io (fd => IO::AIO::poll_fileno,	78	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		79
102	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
103	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
104	my $fh = shift	82	my $fh = shift
105	or die "error while opening: $!";	83	or die "error while opening: $!";
106		84
107	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
108	my $size = -s $fh;	86	my $size = -s $fh;
…		…
117		95
118	# file contents now in $contents	96	# file contents now in $contents
119	print $contents;	97	print $contents;
120		98
121	# exit event loop and program	99	# exit event loop and program
122	Event::unloop;	100	EV::unloop;
123	};	101	};
124	};	102	};
125		103
126	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
127	# check for sockets etc. etc.	105	# check for sockets etc. etc.
128		106
129	# process events as long as there are some:	107	# process events as long as there are some:
130	Event::loop;	108	EV::loop;
131		109
132	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
133		111
134	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
135	directly visible to Perl.	113	directly visible to Perl.
…		…
183		161
184	=cut	162	=cut
185		163
186	package IO::AIO;	164	package IO::AIO;
187		165
188	no warnings;	166	use Carp ();
189	use strict 'vars';	167
		168	use common::sense;
190		169
191	use base 'Exporter';	170	use base 'Exporter';
192		171
193	BEGIN {	172	BEGIN {
194	our $VERSION = '2.4';	173	our $VERSION = '4.0';
195		174
196	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	175	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	176	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	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
		178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
		179	aio_pathsync aio_readahead
		180	aio_rename aio_link aio_move aio_copy aio_group
199	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
200	aio_chown aio_chmod aio_utime);	182	aio_chmod aio_utime aio_truncate
		183	aio_msync aio_mtouch aio_mlock aio_mlockall
		184	aio_statvfs
		185	aio_wd);
		186
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	189	min_parallel max_parallel max_idle idle_timeout
204	nreqs nready npending nthreads	190	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	191	max_poll_time max_poll_reqs
		192	sendfile fadvise madvise
		193	mmap munmap munlock munlockall);
		194
		195	push @AIO_REQ, qw(aio_busy); # not exported
206		196
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	197	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		198
209	require XSLoader;	199	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	200	XSLoader::load ("IO::AIO", $VERSION);
211	}	201	}
212		202
213	=head1 FUNCTIONS	203	=head1 FUNCTIONS
		204
		205	=head2 QUICK OVERVIEW
		206
		207	This section simply lists the prototypes of the most important functions
		208	for quick reference. See the following sections for function-by-function
		209	documentation.
		210
		211	aio_wd $pathname, $callback->($wd)
		212	aio_open $pathname, $flags, $mode, $callback->($fh)
		213	aio_close $fh, $callback->($status)
		214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		217	aio_readahead $fh,$offset,$length, $callback->($retval)
		218	aio_stat $fh_or_path, $callback->($status)
		219	aio_lstat $fh, $callback->($status)
		220	aio_statvfs $fh_or_path, $callback->($statvfs)
		221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		223	aio_truncate $fh_or_path, $offset, $callback->($status)
		224	aio_chmod $fh_or_path, $mode, $callback->($status)
		225	aio_unlink $pathname, $callback->($status)
		226	aio_mknod $pathname, $mode, $dev, $callback->($status)
		227	aio_link $srcpath, $dstpath, $callback->($status)
		228	aio_symlink $srcpath, $dstpath, $callback->($status)
		229	aio_readlink $pathname, $callback->($link)
		230	aio_realpath $pathname, $callback->($link)
		231	aio_rename $srcpath, $dstpath, $callback->($status)
		232	aio_mkdir $pathname, $mode, $callback->($status)
		233	aio_rmdir $pathname, $callback->($status)
		234	aio_readdir $pathname, $callback->($entries)
		235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		238	aio_load $pathname, $data, $callback->($status)
		239	aio_copy $srcpath, $dstpath, $callback->($status)
		240	aio_move $srcpath, $dstpath, $callback->($status)
		241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
		242	aio_rmtree $pathname, $callback->($status)
		243	aio_sync $callback->($status)
		244	aio_syncfs $fh, $callback->($status)
		245	aio_fsync $fh, $callback->($status)
		246	aio_fdatasync $fh, $callback->($status)
		247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		248	aio_pathsync $pathname, $callback->($status)
		249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		252	aio_mlockall $flags, $callback->($status)
		253	aio_group $callback->(...)
		254	aio_nop $callback->()
		255
		256	$prev_pri = aioreq_pri [$pri]
		257	aioreq_nice $pri_adjust
		258
		259	IO::AIO::poll_wait
		260	IO::AIO::poll_cb
		261	IO::AIO::poll
		262	IO::AIO::flush
		263	IO::AIO::max_poll_reqs $nreqs
		264	IO::AIO::max_poll_time $seconds
		265	IO::AIO::min_parallel $nthreads
		266	IO::AIO::max_parallel $nthreads
		267	IO::AIO::max_idle $nthreads
		268	IO::AIO::idle_timeout $seconds
		269	IO::AIO::max_outstanding $maxreqs
		270	IO::AIO::nreqs
		271	IO::AIO::nready
		272	IO::AIO::npending
		273
		274	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		275	IO::AIO::fadvise $fh, $offset, $len, $advice
		276	IO::AIO::madvise $scalar, $offset, $length, $advice
		277	IO::AIO::mprotect $scalar, $offset, $length, $protect
		278	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		279	IO::AIO::munlockall
214		280
215	=head2 AIO REQUEST FUNCTIONS	281	=head2 AIO REQUEST FUNCTIONS
216		282
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	283	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	284	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	285	and they all accept an additional (and optional) C<$callback> argument
220	which must be a code reference. This code reference will get called with	286	which must be a code reference. This code reference will get called with
221	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	287	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
222	perl, which usually delivers "false") as it's sole argument when the given	288	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	289	syscall has been executed asynchronously.
224		290
225	All functions expecting a filehandle keep a copy of the filehandle	291	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	292	internally until the request has finished.
227		293
228	All functions return request objects of type L<IO::AIO::REQ> that allow	294	All functions return request objects of type L<IO::AIO::REQ> that allow
229	further manipulation of those requests while they are in-flight.	295	further manipulation of those requests while they are in-flight.
230		296
231	The pathnames you pass to these routines I<must> be absolute and	297	The pathnames you pass to these routines I<should> be absolute. The
232	encoded as octets. The reason for the former is that at the time the	298	reason for this is that at the time the request is being executed, the
233	request is being executed, the current working directory could have	299	current working directory could have changed. Alternatively, you can make
234	changed. Alternatively, you can make sure that you never change the	300	sure that you never change the current working directory anywhere in
235	current working directory anywhere in the program and then use relative	301	the program and then use relative paths. Lastly, you can take advantage
236	paths.	302	of IO::AIOs working directory abstraction - see the description of the
		303	C<IO::AIO::WD> class later in this document.
237		304
238	To encode pathnames as octets, either make sure you either: a) always pass	305	To encode pathnames as octets, either make sure you either: a) always pass
239	in filenames you got from outside (command line, readdir etc.) without	306	in filenames you got from outside (command line, readdir etc.) without
240	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	307	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
241	your pathnames to the locale (or other) encoding in effect in the user	308	your pathnames to the locale (or other) encoding in effect in the user
242	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	309	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	310	use something else to ensure your scalar has the correct contents.
244		311
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	312	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	313	handles correctly whether it is set or not.
247		314
248	=over 4	315	=over 4
249		316
250	=item $prev_pri = aioreq_pri [$pri]	317	=item $prev_pri = aioreq_pri [$pri]
251		318
…		…
298	by the umask in effect then the request is being executed, so better never	365	by the umask in effect then the request is being executed, so better never
299	change the umask.	366	change the umask.
300		367
301	Example:	368	Example:
302		369
303	aio_open "/etc/passwd", O_RDONLY, 0, sub {	370	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
304	if ($_[0]) {	371	if ($_[0]) {
305	print "open successful, fh is $_[0]\n";	372	print "open successful, fh is $_[0]\n";
306	...	373	...
307	} else {	374	} else {
308	die "open failed: $!\n";	375	die "open failed: $!\n";
309	}	376	}
310	};	377	};
311		378
		379	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		380	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		381	following POSIX and non-POSIX constants are available (missing ones on
		382	your system are, as usual, C<0>):
		383
		384	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		385	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		386	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		387
312		388
313	=item aio_close $fh, $callback->($status)	389	=item aio_close $fh, $callback->($status)
314		390
315	Asynchronously close a file and call the callback with the result	391	Asynchronously close a file and call the callback with the result
316	code. I<WARNING:> although accepted, you should not pass in a perl	392	code.
317	filehandle here, as perl will likely close the file descriptor another
318	time when the filehandle is destroyed. Normally, you can safely call perls
319	C<close> or just let filehandles go out of scope.
320		393
321	This is supposed to be a bug in the API, so that might change. It's	394	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
322	therefore best to avoid this function.	395	closing the file descriptor associated with the filehandle itself.
323		396
		397	Therefore, C<aio_close> will not close the filehandle - instead it will
		398	use dup2 to overwrite the file descriptor with the write-end of a pipe
		399	(the pipe fd will be created on demand and will be cached).
		400
		401	Or in other words: the file descriptor will be closed, but it will not be
		402	free for reuse until the perl filehandle is closed.
		403
		404	=cut
324		405
325	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	406	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
326		407
327	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	408	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
328		409
329	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>	410	Reads or writes C<$length> bytes from or to the specified C<$fh> and
330	into the scalar given by C<$data> and offset C<$dataoffset> and calls the	411	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
331	callback without the actual number of bytes read (or -1 on error, just	412	and calls the callback without the actual number of bytes read (or -1 on
332	like the syscall).	413	error, just like the syscall).
333		414
		415	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		416	offset plus the actual number of bytes read.
		417
334	If C<$offset> is undefined, then the current file offset will be used (and	418	If C<$offset> is undefined, then the current file descriptor offset will
335	updated), otherwise the file offset will not be changed by these calls.	419	be used (and updated), otherwise the file descriptor offset will not be
		420	changed by these calls.
336		421
337	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.	422	If C<$length> is undefined in C<aio_write>, use the remaining length of
		423	C<$data>.
338		424
339	If C<$dataoffset> is less than zero, it will be counted from the end of	425	If C<$dataoffset> is less than zero, it will be counted from the end of
340	C<$data>.	426	C<$data>.
341		427
342	The C<$data> scalar I<MUST NOT> be modified in any way while the request	428	The C<$data> scalar I<MUST NOT> be modified in any way while the request
…		…
356		442
357	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	443	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
358	reading at byte offset C<$in_offset>, and starts writing at the current	444	reading at byte offset C<$in_offset>, and starts writing at the current
359	file offset of C<$out_fh>. Because of that, it is not safe to issue more	445	file offset of C<$out_fh>. Because of that, it is not safe to issue more
360	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	446	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
361	other.	447	other. The same C<$in_fh> works fine though, as this function does not
		448	move or use the file offset of C<$in_fh>.
362		449
		450	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		451	are written, and there is no way to find out how many more bytes have been
		452	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		453	number of bytes written to C<$out_fh>. Only if the result value equals
		454	C<$length> one can assume that C<$length> bytes have been read.
		455
		456	Unlike with other C<aio_> functions, it makes a lot of sense to use
		457	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		458	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		459	the socket I/O will be non-blocking. Note, however, that you can run
		460	into a trap where C<aio_sendfile> reads some data with readahead, then
		461	fails to write all data, and when the socket is ready the next time, the
		462	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		463	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		464	resource usage.
		465
363	This call tries to make use of a native C<sendfile> syscall to provide	466	This call tries to make use of a native C<sendfile>-like syscall to
364	zero-copy operation. For this to work, C<$out_fh> should refer to a	467	provide zero-copy operation. For this to work, C<$out_fh> should refer to
365	socket, and C<$in_fh> should refer to mmap'able file.	468	a socket, and C<$in_fh> should refer to an mmap'able file.
366		469
367	If the native sendfile call fails or is not implemented, it will be	470	If a native sendfile cannot be found or it fails with C<ENOSYS>,
368	emulated, so you can call C<aio_sendfile> on any type of filehandle	471	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		472	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
369	regardless of the limitations of the operating system.	473	type of filehandle regardless of the limitations of the operating system.
370		474
371	Please note, however, that C<aio_sendfile> can read more bytes from	475	As native sendfile syscalls (as practically any non-POSIX interface hacked
372	C<$in_fh> than are written, and there is no way to find out how many	476	together in a hurry to improve benchmark numbers) tend to be rather buggy
373	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	477	on many systems, this implementation tries to work around some known bugs
374	provides the number of bytes written to C<$out_fh>. Only if the result	478	in Linux and FreeBSD kernels (probably others, too), but that might fail,
375	value equals C<$length> one can assume that C<$length> bytes have been	479	so you really really should check the return value of C<aio_sendfile> -
376	read.	480	fewre bytes than expected might have been transferred.
377		481
378		482
379	=item aio_readahead $fh,$offset,$length, $callback->($retval)	483	=item aio_readahead $fh,$offset,$length, $callback->($retval)
380		484
381	C<aio_readahead> populates the page cache with data from a file so that	485	C<aio_readahead> populates the page cache with data from a file so that
…		…
404		508
405	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	509	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
406	error when stat'ing a large file, the results will be silently truncated	510	error when stat'ing a large file, the results will be silently truncated
407	unless perl itself is compiled with large file support.	511	unless perl itself is compiled with large file support.
408		512
		513	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		514	following constants and functions (if not implemented, the constants will
		515	be C<0> and the functions will either C<croak> or fall back on traditional
		516	behaviour).
		517
		518	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		519	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		520	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
		521
409	Example: Print the length of F</etc/passwd>:	522	Example: Print the length of F</etc/passwd>:
410		523
411	aio_stat "/etc/passwd", sub {	524	aio_stat "/etc/passwd", sub {
412	$_[0] and die "stat failed: $!";	525	$_[0] and die "stat failed: $!";
413	print "size is ", -s _, "\n";	526	print "size is ", -s _, "\n";
414	};	527	};
415		528
416		529
		530	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		531
		532	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		533	whether a file handle or path was passed.
		534
		535	On success, the callback is passed a hash reference with the following
		536	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		537	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		538	is passed.
		539
		540	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		541	C<ST_NOSUID>.
		542
		543	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		544	their correct value when available, or to C<0> on systems that do
		545	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		546	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		547	C<ST_NODIRATIME> and C<ST_RELATIME>.
		548
		549	Example: stat C</wd> and dump out the data if successful.
		550
		551	aio_statvfs "/wd", sub {
		552	my $f = $_[0]
		553	or die "statvfs: $!";
		554
		555	use Data::Dumper;
		556	say Dumper $f;
		557	};
		558
		559	# result:
		560	{
		561	bsize => 1024,
		562	bfree => 4333064312,
		563	blocks => 10253828096,
		564	files => 2050765568,
		565	flag => 4096,
		566	favail => 2042092649,
		567	bavail => 4333064312,
		568	ffree => 2042092649,
		569	namemax => 255,
		570	frsize => 1024,
		571	fsid => 1810
		572	}
		573
		574
417	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	575	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
418		576
419	Works like perl's C<utime> function (including the special case of $atime	577	Works like perl's C<utime> function (including the special case of $atime
420	and $mtime being undef). Fractional times are supported if the underlying	578	and $mtime being undef). Fractional times are supported if the underlying
421	syscalls support them.	579	syscalls support them.
…		…
443	aio_chown "path", 0, -1;	601	aio_chown "path", 0, -1;
444	# same as above:	602	# same as above:
445	aio_chown "path", 0, undef;	603	aio_chown "path", 0, undef;
446		604
447		605
		606	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		607
		608	Works like truncate(2) or ftruncate(2).
		609
		610
448	=item aio_chmod $fh_or_path, $mode, $callback->($status)	611	=item aio_chmod $fh_or_path, $mode, $callback->($status)
449		612
450	Works like perl's C<chmod> function.	613	Works like perl's C<chmod> function.
451		614
452		615
…		…
454		617
455	Asynchronously unlink (delete) a file and call the callback with the	618	Asynchronously unlink (delete) a file and call the callback with the
456	result code.	619	result code.
457		620
458		621
459	=item aio_mknod $path, $mode, $dev, $callback->($status)	622	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
460		623
461	[EXPERIMENTAL]	624	[EXPERIMENTAL]
462		625
463	Asynchronously create a device node (or fifo). See mknod(2).	626	Asynchronously create a device node (or fifo). See mknod(2).
464		627
465	The only (POSIX-) portable way of calling this function is:	628	The only (POSIX-) portable way of calling this function is:
466		629
467	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	630	aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
468		631
		632	See C<aio_stat> for info about some potentially helpful extra constants
		633	and functions.
469		634
470	=item aio_link $srcpath, $dstpath, $callback->($status)	635	=item aio_link $srcpath, $dstpath, $callback->($status)
471		636
472	Asynchronously create a new link to the existing object at C<$srcpath> at	637	Asynchronously create a new link to the existing object at C<$srcpath> at
473	the path C<$dstpath> and call the callback with the result code.	638	the path C<$dstpath> and call the callback with the result code.
…		…
477		642
478	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	643	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
479	the path C<$dstpath> and call the callback with the result code.	644	the path C<$dstpath> and call the callback with the result code.
480		645
481		646
482	=item aio_readlink $path, $callback->($link)	647	=item aio_readlink $pathname, $callback->($link)
483		648
484	Asynchronously read the symlink specified by C<$path> and pass it to	649	Asynchronously read the symlink specified by C<$path> and pass it to
485	the callback. If an error occurs, nothing or undef gets passed to the	650	the callback. If an error occurs, nothing or undef gets passed to the
486	callback.	651	callback.
487		652
488		653
		654	=item aio_realpath $pathname, $callback->($path)
		655
		656	Asynchronously make the path absolute and resolve any symlinks in
		657	C<$path>. The resulting path only consists of directories (Same as
		658	L<Cwd::realpath>).
		659
		660	This request can be used to get the absolute path of the current working
		661	directory by passing it a path of F<.> (a single dot).
		662
		663
489	=item aio_rename $srcpath, $dstpath, $callback->($status)	664	=item aio_rename $srcpath, $dstpath, $callback->($status)
490		665
491	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	666	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
492	rename(2) and call the callback with the result code.	667	rename(2) and call the callback with the result code.
493		668
…		…
509		684
510	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	685	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
511	directory (i.e. opendir + readdir + closedir). The entries will not be	686	directory (i.e. opendir + readdir + closedir). The entries will not be
512	sorted, and will B<NOT> include the C<.> and C<..> entries.	687	sorted, and will B<NOT> include the C<.> and C<..> entries.
513		688
514	The callback a single argument which is either C<undef> or an array-ref	689	The callback is passed a single argument which is either C<undef> or an
515	with the filenames.	690	array-ref with the filenames.
516		691
517		692
		693	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		694
		695	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
		696	tune behaviour and output format. In case of an error, C<$entries> will be
		697	C<undef>.
		698
		699	The flags are a combination of the following constants, ORed together (the
		700	flags will also be passed to the callback, possibly modified):
		701
		702	=over 4
		703
		704	=item IO::AIO::READDIR_DENTS
		705
		706	When this flag is off, then the callback gets an arrayref consisting of
		707	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		708	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		709	entry in more detail.
		710
		711	C<$name> is the name of the entry.
		712
		713	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		714
		715	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		716	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		717	C<IO::AIO::DT_WHT>.
		718
		719	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		720	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		721	scalars are read-only: you can not modify them.
		722
		723	C<$inode> is the inode number (which might not be exact on systems with 64
		724	bit inode numbers and 32 bit perls). This field has unspecified content on
		725	systems that do not deliver the inode information.
		726
		727	=item IO::AIO::READDIR_DIRS_FIRST
		728
		729	When this flag is set, then the names will be returned in an order where
		730	likely directories come first, in optimal stat order. This is useful when
		731	you need to quickly find directories, or you want to find all directories
		732	while avoiding to stat() each entry.
		733
		734	If the system returns type information in readdir, then this is used
		735	to find directories directly. Otherwise, likely directories are names
		736	beginning with ".", or otherwise names with no dots, of which names with
		737	short names are tried first.
		738
		739	=item IO::AIO::READDIR_STAT_ORDER
		740
		741	When this flag is set, then the names will be returned in an order
		742	suitable for stat()'ing each one. That is, when you plan to stat()
		743	all files in the given directory, then the returned order will likely
		744	be fastest.
		745
		746	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		747	the likely dirs come first, resulting in a less optimal stat order.
		748
		749	=item IO::AIO::READDIR_FOUND_UNKNOWN
		750
		751	This flag should not be set when calling C<aio_readdirx>. Instead, it
		752	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		753	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
		754	C<$type>'s are known, which can be used to speed up some algorithms.
		755
		756	=back
		757
		758
518	=item aio_load $path, $data, $callback->($status)	759	=item aio_load $pathname, $data, $callback->($status)
519		760
520	This is a composite request that tries to fully load the given file into	761	This is a composite request that tries to fully load the given file into
521	memory. Status is the same as with aio_read.	762	memory. Status is the same as with aio_read.
522		763
523	=cut	764	=cut
524		765
525	sub aio_load($$;$) {	766	sub aio_load($$;$) {
526	aio_block {
527	my ($path, undef, $cb) = @_;	767	my ($path, undef, $cb) = @_;
528	my $data = \$_[1];	768	my $data = \$_[1];
529		769
530	my $pri = aioreq_pri;	770	my $pri = aioreq_pri;
531	my $grp = aio_group $cb;	771	my $grp = aio_group $cb;
		772
		773	aioreq_pri $pri;
		774	add $grp aio_open $path, O_RDONLY, 0, sub {
		775	my $fh = shift
		776	or return $grp->result (-1);
532		777
533	aioreq_pri $pri;	778	aioreq_pri $pri;
534	add $grp aio_open $path, O_RDONLY, 0, sub {
535	my $fh = shift
536	or return $grp->result (-1);
537
538	aioreq_pri $pri;
539	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	779	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
540	$grp->result ($_[0]);	780	$grp->result ($_[0]);
541	};
542	};	781	};
543
544	$grp
545	}	782	};
		783
		784	$grp
546	}	785	}
547		786
548	=item aio_copy $srcpath, $dstpath, $callback->($status)	787	=item aio_copy $srcpath, $dstpath, $callback->($status)
549		788
550	Try to copy the I<file> (directories not supported as either source or	789	Try to copy the I<file> (directories not supported as either source or
551	destination) from C<$srcpath> to C<$dstpath> and call the callback with	790	destination) from C<$srcpath> to C<$dstpath> and call the callback with
552	the C<0> (error) or C<-1> ok.	791	a status of C<0> (ok) or C<-1> (error, see C<$!>).
553		792
554	This is a composite request that it creates the destination file with	793	This is a composite request that creates the destination file with
555	mode 0200 and copies the contents of the source file into it using	794	mode 0200 and copies the contents of the source file into it using
556	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	795	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
557	uid/gid, in that order.	796	uid/gid, in that order.
558		797
559	If an error occurs, the partial destination file will be unlinked, if	798	If an error occurs, the partial destination file will be unlinked, if
…		…
561	errors are being ignored.	800	errors are being ignored.
562		801
563	=cut	802	=cut
564		803
565	sub aio_copy($$;$) {	804	sub aio_copy($$;$) {
566	aio_block {
567	my ($src, $dst, $cb) = @_;	805	my ($src, $dst, $cb) = @_;
568		806
569	my $pri = aioreq_pri;	807	my $pri = aioreq_pri;
570	my $grp = aio_group $cb;	808	my $grp = aio_group $cb;
571		809
572	aioreq_pri $pri;	810	aioreq_pri $pri;
573	add $grp aio_open $src, O_RDONLY, 0, sub {	811	add $grp aio_open $src, O_RDONLY, 0, sub {
574	if (my $src_fh = $_[0]) {	812	if (my $src_fh = $_[0]) {
575	my @stat = stat $src_fh;	813	my @stat = stat $src_fh; # hmm, might block over nfs?
576		814
577	aioreq_pri $pri;	815	aioreq_pri $pri;
578	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	816	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
579	if (my $dst_fh = $_[0]) {	817	if (my $dst_fh = $_[0]) {
580	aioreq_pri $pri;	818	aioreq_pri $pri;
581	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	819	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
582	if ($_[0] == $stat[7]) {	820	if ($_[0] == $stat[7]) {
583	$grp->result (0);	821	$grp->result (0);
584	close $src_fh;	822	close $src_fh;
585		823
586	# those should not normally block. should. should.
587	utime $stat[8], $stat[9], $dst;
588	chmod $stat[2] & 07777, $dst_fh;
589	chown $stat[4], $stat[5], $dst_fh;
590	close $dst_fh;
591	} else {	824	my $ch = sub {
592	$grp->result (-1);
593	close $src_fh;
594	close $dst_fh;
595
596	aioreq $pri;	825	aioreq_pri $pri;
		826	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		827	aioreq_pri $pri;
		828	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		829	aioreq_pri $pri;
597	add $grp aio_unlink $dst;	830	add $grp aio_close $dst_fh;
		831	}
		832	};
598	}	833	};
		834
		835	aioreq_pri $pri;
		836	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		837	if ($_[0] < 0 && $! == ENOSYS) {
		838	aioreq_pri $pri;
		839	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		840	} else {
		841	$ch->();
		842	}
		843	};
		844	} else {
		845	$grp->result (-1);
		846	close $src_fh;
		847	close $dst_fh;
		848
		849	aioreq $pri;
		850	add $grp aio_unlink $dst;
599	};	851	}
600	} else {
601	$grp->result (-1);
602	}	852	};
		853	} else {
		854	$grp->result (-1);
603	},	855	}
604
605	} else {
606	$grp->result (-1);
607	}	856	},
		857
		858	} else {
		859	$grp->result (-1);
608	};	860	}
609
610	$grp
611	}	861	};
		862
		863	$grp
612	}	864	}
613		865
614	=item aio_move $srcpath, $dstpath, $callback->($status)	866	=item aio_move $srcpath, $dstpath, $callback->($status)
615		867
616	Try to move the I<file> (directories not supported as either source or	868	Try to move the I<file> (directories not supported as either source or
617	destination) from C<$srcpath> to C<$dstpath> and call the callback with	869	destination) from C<$srcpath> to C<$dstpath> and call the callback with
618	the C<0> (error) or C<-1> ok.	870	a status of C<0> (ok) or C<-1> (error, see C<$!>).
619		871
620	This is a composite request that tries to rename(2) the file first. If	872	This is a composite request that tries to rename(2) the file first; if
621	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	873	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
622	that is successful, unlinking the C<$srcpath>.	874	that is successful, unlinks the C<$srcpath>.
623		875
624	=cut	876	=cut
625		877
626	sub aio_move($$;$) {	878	sub aio_move($$;$) {
627	aio_block {
628	my ($src, $dst, $cb) = @_;	879	my ($src, $dst, $cb) = @_;
629		880
630	my $pri = aioreq_pri;	881	my $pri = aioreq_pri;
631	my $grp = aio_group $cb;	882	my $grp = aio_group $cb;
632		883
633	aioreq_pri $pri;	884	aioreq_pri $pri;
634	add $grp aio_rename $src, $dst, sub {	885	add $grp aio_rename $src, $dst, sub {
635	if ($_[0] && $! == EXDEV) {	886	if ($_[0] && $! == EXDEV) {
636	aioreq_pri $pri;	887	aioreq_pri $pri;
637	add $grp aio_copy $src, $dst, sub {	888	add $grp aio_copy $src, $dst, sub {
638	$grp->result ($_[0]);
639
640	if (!$_[0]) {
641	aioreq_pri $pri;
642	add $grp aio_unlink $src;
643	}
644	};
645	} else {
646	$grp->result ($_[0]);	889	$grp->result ($_[0]);
		890
		891	unless ($_[0]) {
		892	aioreq_pri $pri;
		893	add $grp aio_unlink $src;
		894	}
647	}	895	};
		896	} else {
		897	$grp->result ($_[0]);
648	};	898	}
649
650	$grp
651	}	899	};
		900
		901	$grp
652	}	902	}
653		903
654	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	904	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
655		905
656	Scans a directory (similar to C<aio_readdir>) but additionally tries to	906	Scans a directory (similar to C<aio_readdir>) but additionally tries to
657	efficiently separate the entries of directory C<$path> into two sets of	907	efficiently separate the entries of directory C<$path> into two sets of
658	names, directories you can recurse into (directories), and ones you cannot	908	names, directories you can recurse into (directories), and ones you cannot
659	recurse into (everything else, including symlinks to directories).	909	recurse into (everything else, including symlinks to directories).
…		…
676		926
677	Implementation notes.	927	Implementation notes.
678		928
679	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	929	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
680		930
		931	If readdir returns file type information, then this is used directly to
		932	find directories.
		933
681	After reading the directory, the modification time, size etc. of the	934	Otherwise, after reading the directory, the modification time, size etc.
682	directory before and after the readdir is checked, and if they match (and	935	of the directory before and after the readdir is checked, and if they
683	isn't the current time), the link count will be used to decide how many	936	match (and isn't the current time), the link count will be used to decide
684	entries are directories (if >= 2). Otherwise, no knowledge of the number	937	how many entries are directories (if >= 2). Otherwise, no knowledge of the
685	of subdirectories will be assumed.	938	number of subdirectories will be assumed.
686		939
687	Then entries will be sorted into likely directories (everything without	940	Then entries will be sorted into likely directories a non-initial dot
688	a non-initial dot currently) and likely non-directories (everything	941	currently) and likely non-directories (see C<aio_readdirx>). Then every
689	else). Then every entry plus an appended C</.> will be C<stat>'ed,	942	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
690	likely directories first. If that succeeds, it assumes that the entry	943	in order of their inode numbers. If that succeeds, it assumes that the
691	is a directory or a symlink to directory (which will be checked	944	entry is a directory or a symlink to directory (which will be checked
692	seperately). This is often faster than stat'ing the entry itself because	945	separately). This is often faster than stat'ing the entry itself because
693	filesystems might detect the type of the entry without reading the inode	946	filesystems might detect the type of the entry without reading the inode
694	data (e.g. ext2fs filetype feature).	947	data (e.g. ext2fs filetype feature), even on systems that cannot return
		948	the filetype information on readdir.
695		949
696	If the known number of directories (link count - 2) has been reached, the	950	If the known number of directories (link count - 2) has been reached, the
697	rest of the entries is assumed to be non-directories.	951	rest of the entries is assumed to be non-directories.
698		952
699	This only works with certainty on POSIX (= UNIX) filesystems, which	953	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
704	directory counting heuristic.	958	directory counting heuristic.
705		959
706	=cut	960	=cut
707		961
708	sub aio_scandir($$;$) {	962	sub aio_scandir($$;$) {
709	aio_block {
710	my ($path, $maxreq, $cb) = @_;	963	my ($path, $maxreq, $cb) = @_;
711		964
712	my $pri = aioreq_pri;	965	my $pri = aioreq_pri;
713		966
714	my $grp = aio_group $cb;	967	my $grp = aio_group $cb;
715		968
716	$maxreq = 4 if $maxreq <= 0;	969	$maxreq = 4 if $maxreq <= 0;
		970
		971	# get a wd object
		972
		973	aioreq_pri $pri;
		974	add $grp aio_wd $path, sub {
		975	my $wd = [shift, "."];
717		976
718	# stat once	977	# stat once
719	aioreq_pri $pri;	978	aioreq_pri $pri;
720	add $grp aio_stat $path, sub {	979	add $grp aio_stat $wd, sub {
721	return $grp->result () if $_[0];	980	return $grp->result () if $_[0];
722	my $now = time;	981	my $now = time;
723	my $hash1 = join ":", (stat _)[0,1,3,7,9];	982	my $hash1 = join ":", (stat _)[0,1,3,7,9];
724		983
725	# read the directory entries	984	# read the directory entries
726	aioreq_pri $pri;	985	aioreq_pri $pri;
727	add $grp aio_readdir $path, sub {	986	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
728	my $entries = shift	987	my $entries = shift
729	or return $grp->result ();	988	or return $grp->result ();
730		989
731	# stat the dir another time	990	# stat the dir another time
732	aioreq_pri $pri;	991	aioreq_pri $pri;
733	add $grp aio_stat $path, sub {	992	add $grp aio_stat $wd, sub {
734	my $hash2 = join ":", (stat _)[0,1,3,7,9];	993	my $hash2 = join ":", (stat _)[0,1,3,7,9];
735		994
736	my $ndirs;	995	my $ndirs;
737		996
738	# take the slow route if anything looks fishy	997	# take the slow route if anything looks fishy
739	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	998	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
740	$ndirs = -1;	999	$ndirs = -1;
741	} else {	1000	} else {
742	# if nlink == 2, we are finished	1001	# if nlink == 2, we are finished
743	# on non-posix-fs's, we rely on nlink < 2	1002	# for non-posix-fs's, we rely on nlink < 2
744	$ndirs = (stat _)[3] - 2	1003	$ndirs = (stat _)[3] - 2
745	or return $grp->result ([], $entries);	1004	or return $grp->result ([], $entries);
746	}	1005	}
747		1006
748	# sort into likely dirs and likely nondirs
749	# dirs == files without ".", short entries first
750	$entries = [map $_->[0],
751	sort { $b->[1] cmp $a->[1] }
752	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
753	@$entries];
754
755	my (@dirs, @nondirs);	1007	my (@dirs, @nondirs);
756		1008
757	my $statgrp = add $grp aio_group sub {	1009	my $statgrp = add $grp aio_group sub {
758	$grp->result (\@dirs, \@nondirs);	1010	$grp->result (\@dirs, \@nondirs);
759	};	1011	};
760		1012
761	limit $statgrp $maxreq;	1013	limit $statgrp $maxreq;
762	feed $statgrp sub {	1014	feed $statgrp sub {
763	return unless @$entries;	1015	return unless @$entries;
764	my $entry = pop @$entries;	1016	my $entry = shift @$entries;
765		1017
766	aioreq_pri $pri;	1018	aioreq_pri $pri;
		1019	$wd->[1] = "$entry/.";
767	add $statgrp aio_stat "$path/$entry/.", sub {	1020	add $statgrp aio_stat $wd, sub {
768	if ($_[0] < 0) {	1021	if ($_[0] < 0) {
769	push @nondirs, $entry;	1022	push @nondirs, $entry;
770	} else {	1023	} else {
771	# need to check for real directory	1024	# need to check for real directory
772	aioreq_pri $pri;	1025	aioreq_pri $pri;
		1026	$wd->[1] = $entry;
773	add $statgrp aio_lstat "$path/$entry", sub {	1027	add $statgrp aio_lstat $wd, sub {
774	if (-d _) {	1028	if (-d _) {
775	push @dirs, $entry;	1029	push @dirs, $entry;
776		1030
777	unless (--$ndirs) {	1031	unless (--$ndirs) {
778	push @nondirs, @$entries;	1032	push @nondirs, @$entries;
…		…
786	};	1040	};
787	};	1041	};
788	};	1042	};
789	};	1043	};
790	};	1044	};
791
792	$grp
793	}	1045	};
		1046
		1047	$grp
794	}	1048	}
795		1049
796	=item aio_rmtree $path, $callback->($status)	1050	=item aio_rmtree $pathname, $callback->($status)
797		1051
798	Delete a directory tree starting (and including) C<$path>, return the	1052	Delete a directory tree starting (and including) C<$path>, return the
799	status of the final C<rmdir> only. This is a composite request that	1053	status of the final C<rmdir> only. This is a composite request that
800	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1054	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
801	everything else.	1055	everything else.
802		1056
803	=cut	1057	=cut
804		1058
805	sub aio_rmtree;	1059	sub aio_rmtree;
806	sub aio_rmtree($;$) {	1060	sub aio_rmtree($;$) {
807	aio_block {
808	my ($path, $cb) = @_;	1061	my ($path, $cb) = @_;
809		1062
810	my $pri = aioreq_pri;	1063	my $pri = aioreq_pri;
811	my $grp = aio_group $cb;	1064	my $grp = aio_group $cb;
812		1065
813	aioreq_pri $pri;	1066	aioreq_pri $pri;
814	add $grp aio_scandir $path, 0, sub {	1067	add $grp aio_scandir $path, 0, sub {
815	my ($dirs, $nondirs) = @_;	1068	my ($dirs, $nondirs) = @_;
816		1069
817	my $dirgrp = aio_group sub {	1070	my $dirgrp = aio_group sub {
818	add $grp aio_rmdir $path, sub {	1071	add $grp aio_rmdir $path, sub {
819	$grp->result ($_[0]);	1072	$grp->result ($_[0]);
820	};
821	};	1073	};
822
823	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
824	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
825
826	add $grp $dirgrp;
827	};	1074	};
828		1075
829	$grp	1076	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1077	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1078
		1079	add $grp $dirgrp;
830	}	1080	};
		1081
		1082	$grp
831	}	1083	}
		1084
		1085	=item aio_sync $callback->($status)
		1086
		1087	Asynchronously call sync and call the callback when finished.
832		1088
833	=item aio_fsync $fh, $callback->($status)	1089	=item aio_fsync $fh, $callback->($status)
834		1090
835	Asynchronously call fsync on the given filehandle and call the callback	1091	Asynchronously call fsync on the given filehandle and call the callback
836	with the fsync result code.	1092	with the fsync result code.
…		…
840	Asynchronously call fdatasync on the given filehandle and call the	1096	Asynchronously call fdatasync on the given filehandle and call the
841	callback with the fdatasync result code.	1097	callback with the fdatasync result code.
842		1098
843	If this call isn't available because your OS lacks it or it couldn't be	1099	If this call isn't available because your OS lacks it or it couldn't be
844	detected, it will be emulated by calling C<fsync> instead.	1100	detected, it will be emulated by calling C<fsync> instead.
		1101
		1102	=item aio_syncfs $fh, $callback->($status)
		1103
		1104	Asynchronously call the syncfs syscall to sync the filesystem associated
		1105	to the given filehandle and call the callback with the syncfs result
		1106	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1107	errno to C<ENOSYS> nevertheless.
		1108
		1109	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1110
		1111	Sync the data portion of the file specified by C<$offset> and C<$length>
		1112	to disk (but NOT the metadata), by calling the Linux-specific
		1113	sync_file_range call. If sync_file_range is not available or it returns
		1114	ENOSYS, then fdatasync or fsync is being substituted.
		1115
		1116	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1117	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1118	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1119	manpage for details.
		1120
		1121	=item aio_pathsync $pathname, $callback->($status)
		1122
		1123	This request tries to open, fsync and close the given path. This is a
		1124	composite request intended to sync directories after directory operations
		1125	(E.g. rename). This might not work on all operating systems or have any
		1126	specific effect, but usually it makes sure that directory changes get
		1127	written to disc. It works for anything that can be opened for read-only,
		1128	not just directories.
		1129
		1130	Future versions of this function might fall back to other methods when
		1131	C<fsync> on the directory fails (such as calling C<sync>).
		1132
		1133	Passes C<0> when everything went ok, and C<-1> on error.
		1134
		1135	=cut
		1136
		1137	sub aio_pathsync($;$) {
		1138	my ($path, $cb) = @_;
		1139
		1140	my $pri = aioreq_pri;
		1141	my $grp = aio_group $cb;
		1142
		1143	aioreq_pri $pri;
		1144	add $grp aio_open $path, O_RDONLY, 0, sub {
		1145	my ($fh) = @_;
		1146	if ($fh) {
		1147	aioreq_pri $pri;
		1148	add $grp aio_fsync $fh, sub {
		1149	$grp->result ($_[0]);
		1150
		1151	aioreq_pri $pri;
		1152	add $grp aio_close $fh;
		1153	};
		1154	} else {
		1155	$grp->result (-1);
		1156	}
		1157	};
		1158
		1159	$grp
		1160	}
		1161
		1162	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1163
		1164	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1165	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1166	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1167	scalar must only be modified in-place while an aio operation is pending on
		1168	it).
		1169
		1170	It calls the C<msync> function of your OS, if available, with the memory
		1171	area starting at C<$offset> in the string and ending C<$length> bytes
		1172	later. If C<$length> is negative, counts from the end, and if C<$length>
		1173	is C<undef>, then it goes till the end of the string. The flags can be
		1174	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1175	C<IO::AIO::MS_SYNC>.
		1176
		1177	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1178
		1179	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1180	scalars.
		1181
		1182	It touches (reads or writes) all memory pages in the specified
		1183	range inside the scalar. All caveats and parameters are the same
		1184	as for C<aio_msync>, above, except for flags, which must be either
		1185	C<0> (which reads all pages and ensures they are instantiated) or
		1186	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1187	writing an octet from it, which dirties the page).
		1188
		1189	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1190
		1191	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1192	scalars.
		1193
		1194	It reads in all the pages of the underlying storage into memory (if any)
		1195	and locks them, so they are not getting swapped/paged out or removed.
		1196
		1197	If C<$length> is undefined, then the scalar will be locked till the end.
		1198
		1199	On systems that do not implement C<mlock>, this function returns C<-1>
		1200	and sets errno to C<ENOSYS>.
		1201
		1202	Note that the corresponding C<munlock> is synchronous and is
		1203	documented under L<MISCELLANEOUS FUNCTIONS>.
		1204
		1205	Example: open a file, mmap and mlock it - both will be undone when
		1206	C<$data> gets destroyed.
		1207
		1208	open my $fh, "<", $path or die "$path: $!";
		1209	my $data;
		1210	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1211	aio_mlock $data; # mlock in background
		1212
		1213	=item aio_mlockall $flags, $callback->($status)
		1214
		1215	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1216	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1217
		1218	On systems that do not implement C<mlockall>, this function returns C<-1>
		1219	and sets errno to C<ENOSYS>.
		1220
		1221	Note that the corresponding C<munlockall> is synchronous and is
		1222	documented under L<MISCELLANEOUS FUNCTIONS>.
		1223
		1224	Example: asynchronously lock all current and future pages into memory.
		1225
		1226	aio_mlockall IO::AIO::MCL_FUTURE;
845		1227
846	=item aio_group $callback->(...)	1228	=item aio_group $callback->(...)
847		1229
848	This is a very special aio request: Instead of doing something, it is a	1230	This is a very special aio request: Instead of doing something, it is a
849	container for other aio requests, which is useful if you want to bundle	1231	container for other aio requests, which is useful if you want to bundle
…		…
887	immense (it blocks a thread for a long time) so do not use this function	1269	immense (it blocks a thread for a long time) so do not use this function
888	except to put your application under artificial I/O pressure.	1270	except to put your application under artificial I/O pressure.
889		1271
890	=back	1272	=back
891		1273
		1274
		1275	=head2 IO::AIO::WD - multiple working directories
		1276
		1277	Your process only has one current working directory, which is used by all
		1278	threads. This makes it hard to use relative paths (some other component
		1279	could call C<chdir> at any time, and it is hard to control when the path
		1280	will be used by IO::AIO).
		1281
		1282	One solution for this is to always use absolute paths. This usually works,
		1283	but can be quite slow (the kernel has to walk the whole path on every
		1284	access), and can also be a hassle to implement.
		1285
		1286	Newer POSIX systems have a number of functions (openat, fdopendir,
		1287	futimensat and so on) that make it possible to specify working directories
		1288	per operation.
		1289
		1290	For portability, and because the clowns who "designed", or shall I write,
		1291	perpetrated this new interface were obviously half-drunk, this abstraction
		1292	cannot be perfect, though.
		1293
		1294	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1295	object. This object stores the canonicalised, absolute version of the
		1296	path, and on systems that allow it, also a directory file descriptor.
		1297
		1298	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1299	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1300	object and a pathname instead. If the pathname is absolute, the
		1301	IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative
		1302	to that IO::AIO::WD object.
		1303
		1304	For example, to get a wd object for F</etc> and then stat F<passwd>
		1305	inside, you would write:
		1306
		1307	aio_wd "/etc", sub {
		1308	my $etcdir = shift;
		1309
		1310	# although $etcdir can be undef on error, there is generally no reason
		1311	# to check for errors here, as aio_stat will fail with ENOENT
		1312	# when $etcdir is undef.
		1313
		1314	aio_stat [$etcdir, "passwd"], sub {
		1315	# yay
		1316	};
		1317	};
		1318
		1319	This shows that creating an IO::AIO::WD object is itself a potentially
		1320	blocking operation, which is why it is done asynchronously.
		1321
		1322	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1323	object and the pathname string, so you could write the following without
		1324	causing any issues due to C<$path> getting reused:
		1325
		1326	my $path = [$wd, undef];
		1327
		1328	for my $name (qw(abc def ghi)) {
		1329	$path->[1] = $name;
		1330	aio_stat $path, sub {
		1331	# ...
		1332	};
		1333	}
		1334
		1335	There are some caveats: when directories get renamed (or deleted), the
		1336	pathname string doesn't change, so will point to the new directory (or
		1337	nowhere at all), while the directory fd, if available on the system,
		1338	will still point to the original directory. Most functions accepting a
		1339	pathname will use the directory fd on newer systems, and the string on
		1340	older systems. Some functions (such as realpath) will always rely on the
		1341	string form of the pathname.
		1342
		1343	So this fucntionality is mainly useful to get some protection against
		1344	C<chdir>, to easily get an absolute path out of a relative path for future
		1345	reference, and to speed up doing many operations in the same directory
		1346	(e.g. when stat'ing all files in a directory).
		1347
		1348	The following functions implement this working directory abstraction:
		1349
		1350	=over 4
		1351
		1352	=item aio_wd $pathname, $callback->($wd)
		1353
		1354	Asynchonously canonicalise the given pathname and convert it to an
		1355	IO::AIO::WD object representing it. If possible and supported on the
		1356	system, also open a directory fd to speed up pathname resolution relative
		1357	to this working directory.
		1358
		1359	If something goes wrong, then C<undef> is passwd to the callback instead
		1360	of a working directory object and C<$!> is set appropriately. Since
		1361	passing C<undef> as working directory component of a pathname fails the
		1362	request with C<ENOENT>, there is often no need for error checking in the
		1363	C<aio_wd> callback, as future requests using the value will fail in the
		1364	expected way.
		1365
		1366	If this call isn't available because your OS lacks it or it couldn't be
		1367	detected, it will be emulated by calling C<fsync> instead.
		1368
		1369	=item IO::AIO::CWD
		1370
		1371	This is a compiletime constant (object) that represents the process
		1372	current working directory.
		1373
		1374	Specifying this object as working directory object for a pathname is as
		1375	if the pathname would be specified directly, without a directory object,
		1376	e.g., these calls are functionally identical:
		1377
		1378	aio_stat "somefile", sub { ... };
		1379	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1380
		1381	=back
		1382
		1383
892	=head2 IO::AIO::REQ CLASS	1384	=head2 IO::AIO::REQ CLASS
893		1385
894	All non-aggregate C<aio_*> functions return an object of this class when	1386	All non-aggregate C<aio_*> functions return an object of this class when
895	called in non-void context.	1387	called in non-void context.
896		1388
…		…
899	=item cancel $req	1391	=item cancel $req
900		1392
901	Cancels the request, if possible. Has the effect of skipping execution	1393	Cancels the request, if possible. Has the effect of skipping execution
902	when entering the B<execute> state and skipping calling the callback when	1394	when entering the B<execute> state and skipping calling the callback when
903	entering the the B<result> state, but will leave the request otherwise	1395	entering the the B<result> state, but will leave the request otherwise
904	untouched. That means that requests that currently execute will not be	1396	untouched (with the exception of readdir). That means that requests that
905	stopped and resources held by the request will not be freed prematurely.	1397	currently execute will not be stopped and resources held by the request
		1398	will not be freed prematurely.
906		1399
907	=item cb $req $callback->(...)	1400	=item cb $req $callback->(...)
908		1401
909	Replace (or simply set) the callback registered to the request.	1402	Replace (or simply set) the callback registered to the request.
910		1403
…		…
961	Their lifetime, simplified, looks like this: when they are empty, they	1454	Their lifetime, simplified, looks like this: when they are empty, they
962	will finish very quickly. If they contain only requests that are in the	1455	will finish very quickly. If they contain only requests that are in the
963	C<done> state, they will also finish. Otherwise they will continue to	1456	C<done> state, they will also finish. Otherwise they will continue to
964	exist.	1457	exist.
965		1458
966	That means after creating a group you have some time to add requests. And	1459	That means after creating a group you have some time to add requests
967	in the callbacks of those requests, you can add further requests to the	1460	(precisely before the callback has been invoked, which is only done within
968	group. And only when all those requests have finished will the the group	1461	the C<poll_cb>). And in the callbacks of those requests, you can add
969	itself finish.	1462	further requests to the group. And only when all those requests have
		1463	finished will the the group itself finish.
970		1464
971	=over 4	1465	=over 4
972		1466
973	=item add $grp ...	1467	=item add $grp ...
974		1468
…		…
983	=item $grp->cancel_subs	1477	=item $grp->cancel_subs
984		1478
985	Cancel all subrequests and clears any feeder, but not the group request	1479	Cancel all subrequests and clears any feeder, but not the group request
986	itself. Useful when you queued a lot of events but got a result early.	1480	itself. Useful when you queued a lot of events but got a result early.
987		1481
		1482	The group request will finish normally (you cannot add requests to the
		1483	group).
		1484
988	=item $grp->result (...)	1485	=item $grp->result (...)
989		1486
990	Set the result value(s) that will be passed to the group callback when all	1487	Set the result value(s) that will be passed to the group callback when all
991	subrequests have finished and set thre groups errno to the current value	1488	subrequests have finished and set the groups errno to the current value
992	of errno (just like calling C<errno> without an error number). By default,	1489	of errno (just like calling C<errno> without an error number). By default,
993	no argument will be passed and errno is zero.	1490	no argument will be passed and errno is zero.
994		1491
995	=item $grp->errno ([$errno])	1492	=item $grp->errno ([$errno])
996		1493
…		…
1007	=item feed $grp $callback->($grp)	1504	=item feed $grp $callback->($grp)
1008		1505
1009	Sets a feeder/generator on this group: every group can have an attached	1506	Sets a feeder/generator on this group: every group can have an attached
1010	generator that generates requests if idle. The idea behind this is that,	1507	generator that generates requests if idle. The idea behind this is that,
1011	although you could just queue as many requests as you want in a group,	1508	although you could just queue as many requests as you want in a group,
1012	this might starve other requests for a potentially long time. For	1509	this might starve other requests for a potentially long time. For example,
1013	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1510	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1014	requests, delaying any later requests for a long time.	1511	requests, delaying any later requests for a long time.
1015		1512
1016	To avoid this, and allow incremental generation of requests, you can	1513	To avoid this, and allow incremental generation of requests, you can
1017	instead a group and set a feeder on it that generates those requests. The	1514	instead a group and set a feeder on it that generates those requests. The
1018	feed callback will be called whenever there are few enough (see C<limit>,	1515	feed callback will be called whenever there are few enough (see C<limit>,
…		…
1023	not impose any limits).	1520	not impose any limits).
1024		1521
1025	If the feed does not queue more requests when called, it will be	1522	If the feed does not queue more requests when called, it will be
1026	automatically removed from the group.	1523	automatically removed from the group.
1027		1524
1028	If the feed limit is C<0>, it will be set to C<2> automatically.	1525	If the feed limit is C<0> when this method is called, it will be set to
		1526	C<2> automatically.
1029		1527
1030	Example:	1528	Example:
1031		1529
1032	# stat all files in @files, but only ever use four aio requests concurrently:	1530	# stat all files in @files, but only ever use four aio requests concurrently:
1033		1531
…		…
1045	Sets the feeder limit for the group: The feeder will be called whenever	1543	Sets the feeder limit for the group: The feeder will be called whenever
1046	the group contains less than this many requests.	1544	the group contains less than this many requests.
1047		1545
1048	Setting the limit to C<0> will pause the feeding process.	1546	Setting the limit to C<0> will pause the feeding process.
1049		1547
		1548	The default value for the limit is C<0>, but note that setting a feeder
		1549	automatically bumps it up to C<2>.
		1550
1050	=back	1551	=back
1051		1552
1052	=head2 SUPPORT FUNCTIONS	1553	=head2 SUPPORT FUNCTIONS
1053		1554
1054	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1555	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
1056	=over 4	1557	=over 4
1057		1558
1058	=item $fileno = IO::AIO::poll_fileno	1559	=item $fileno = IO::AIO::poll_fileno
1059		1560
1060	Return the I<request result pipe file descriptor>. This filehandle must be	1561	Return the I<request result pipe file descriptor>. This filehandle must be
1061	polled for reading by some mechanism outside this module (e.g. Event or	1562	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1062	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1563	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1063	to call C<poll_cb> to check the results.	1564	you have to call C<poll_cb> to check the results.
1064		1565
1065	See C<poll_cb> for an example.	1566	See C<poll_cb> for an example.
1066		1567
1067	=item IO::AIO::poll_cb	1568	=item IO::AIO::poll_cb
1068		1569
1069	Process some outstanding events on the result pipe. You have to call this	1570	Process some outstanding events on the result pipe. You have to call
1070	regularly. Returns the number of events processed. Returns immediately	1571	this regularly. Returns C<0> if all events could be processed (or there
1071	when no events are outstanding. The amount of events processed depends on	1572	were no events to process), or C<-1> if it returned earlier for whatever
1072	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1573	reason. Returns immediately when no events are outstanding. The amount of
		1574	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1575	C<IO::AIO::max_poll_time>.
1073		1576
1074	If not all requests were processed for whatever reason, the filehandle	1577	If not all requests were processed for whatever reason, the filehandle
1075	will still be ready when C<poll_cb> returns.	1578	will still be ready when C<poll_cb> returns, so normally you don't have to
		1579	do anything special to have it called later.
		1580
		1581	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1582	ready, it can be beneficial to call this function from loops which submit
		1583	a lot of requests, to make sure the results get processed when they become
		1584	available and not just when the loop is finished and the event loop takes
		1585	over again. This function returns very fast when there are no outstanding
		1586	requests.
1076		1587
1077	Example: Install an Event watcher that automatically calls	1588	Example: Install an Event watcher that automatically calls
1078	IO::AIO::poll_cb with high priority:	1589	IO::AIO::poll_cb with high priority (more examples can be found in the
		1590	SYNOPSIS section, at the top of this document):
1079		1591
1080	Event->io (fd => IO::AIO::poll_fileno,	1592	Event->io (fd => IO::AIO::poll_fileno,
1081	poll => 'r', async => 1,	1593	poll => 'r', async => 1,
1082	cb => \&IO::AIO::poll_cb);	1594	cb => \&IO::AIO::poll_cb);
		1595
		1596	=item IO::AIO::poll_wait
		1597
		1598	If there are any outstanding requests and none of them in the result
		1599	phase, wait till the result filehandle becomes ready for reading (simply
		1600	does a C<select> on the filehandle. This is useful if you want to
		1601	synchronously wait for some requests to finish).
		1602
		1603	See C<nreqs> for an example.
		1604
		1605	=item IO::AIO::poll
		1606
		1607	Waits until some requests have been handled.
		1608
		1609	Returns the number of requests processed, but is otherwise strictly
		1610	equivalent to:
		1611
		1612	IO::AIO::poll_wait, IO::AIO::poll_cb
		1613
		1614	=item IO::AIO::flush
		1615
		1616	Wait till all outstanding AIO requests have been handled.
		1617
		1618	Strictly equivalent to:
		1619
		1620	IO::AIO::poll_wait, IO::AIO::poll_cb
		1621	while IO::AIO::nreqs;
1083		1622
1084	=item IO::AIO::max_poll_reqs $nreqs	1623	=item IO::AIO::max_poll_reqs $nreqs
1085		1624
1086	=item IO::AIO::max_poll_time $seconds	1625	=item IO::AIO::max_poll_time $seconds
1087		1626
…		…
1112	# use a low priority so other tasks have priority	1651	# use a low priority so other tasks have priority
1113	Event->io (fd => IO::AIO::poll_fileno,	1652	Event->io (fd => IO::AIO::poll_fileno,
1114	poll => 'r', nice => 1,	1653	poll => 'r', nice => 1,
1115	cb => &IO::AIO::poll_cb);	1654	cb => &IO::AIO::poll_cb);
1116		1655
1117	=item IO::AIO::poll_wait
1118
1119	If there are any outstanding requests and none of them in the result
1120	phase, wait till the result filehandle becomes ready for reading (simply
1121	does a C<select> on the filehandle. This is useful if you want to
1122	synchronously wait for some requests to finish).
1123
1124	See C<nreqs> for an example.
1125
1126	=item IO::AIO::poll
1127
1128	Waits until some requests have been handled.
1129
1130	Returns the number of requests processed, but is otherwise strictly
1131	equivalent to:
1132
1133	IO::AIO::poll_wait, IO::AIO::poll_cb
1134
1135	=item IO::AIO::flush
1136
1137	Wait till all outstanding AIO requests have been handled.
1138
1139	Strictly equivalent to:
1140
1141	IO::AIO::poll_wait, IO::AIO::poll_cb
1142	while IO::AIO::nreqs;
1143
1144	=back	1656	=back
1145		1657
1146	=head3 CONTROLLING THE NUMBER OF THREADS	1658	=head3 CONTROLLING THE NUMBER OF THREADS
1147		1659
1148	=over	1660	=over
…		…
1181		1693
1182	Under normal circumstances you don't need to call this function.	1694	Under normal circumstances you don't need to call this function.
1183		1695
1184	=item IO::AIO::max_idle $nthreads	1696	=item IO::AIO::max_idle $nthreads
1185		1697
1186	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1698	Limit the number of threads (default: 4) that are allowed to idle
1187	threads that did not get a request to process within 10 seconds). That	1699	(i.e., threads that did not get a request to process within the idle
1188	means if a thread becomes idle while C<$nthreads> other threads are also	1700	timeout (default: 10 seconds). That means if a thread becomes idle while
1189	idle, it will free its resources and exit.	1701	C<$nthreads> other threads are also idle, it will free its resources and
		1702	exit.
1190		1703
1191	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1704	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1192	to allow for extremely high load situations, but want to free resources	1705	to allow for extremely high load situations, but want to free resources
1193	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1706	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1194		1707
1195	The default is probably ok in most situations, especially if thread	1708	The default is probably ok in most situations, especially if thread
1196	creation is fast. If thread creation is very slow on your system you might	1709	creation is fast. If thread creation is very slow on your system you might
1197	want to use larger values.	1710	want to use larger values.
1198		1711
		1712	=item IO::AIO::idle_timeout $seconds
		1713
		1714	Sets the minimum idle timeout (default 10) after which worker threads are
		1715	allowed to exit. SEe C<IO::AIO::max_idle>.
		1716
1199	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1717	=item IO::AIO::max_outstanding $maxreqs
		1718
		1719	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1720	you do queue up more than this number of requests, the next call to
		1721	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1722	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1723	longer exceeded.
		1724
		1725	In other words, this setting does not enforce a queue limit, but can be
		1726	used to make poll functions block if the limit is exceeded.
1200		1727
1201	This is a very bad function to use in interactive programs because it	1728	This is a very bad function to use in interactive programs because it
1202	blocks, and a bad way to reduce concurrency because it is inexact: Better	1729	blocks, and a bad way to reduce concurrency because it is inexact: Better
1203	use an C<aio_group> together with a feed callback.	1730	use an C<aio_group> together with a feed callback.
1204		1731
1205	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1732	It's main use is in scripts without an event loop - when you want to stat
1206	to queue up more than this number of requests, the next call to the	1733	a lot of files, you can write somehting like this:
1207	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1208	function will block until the limit is no longer exceeded.
1209		1734
1210	The default value is very large, so there is no practical limit on the	1735	IO::AIO::max_outstanding 32;
1211	number of outstanding requests.
1212		1736
1213	You can still queue as many requests as you want. Therefore,	1737	for my $path (...) {
1214	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1738	aio_stat $path , ...;
1215	as a stop gap to shield against fatal memory overflow (with large values).	1739	IO::AIO::poll_cb;
		1740	}
		1741
		1742	IO::AIO::flush;
		1743
		1744	The call to C<poll_cb> inside the loop will normally return instantly, but
		1745	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1746	some requests have been handled. This keeps the loop from pushing a large
		1747	number of C<aio_stat> requests onto the queue.
		1748
		1749	The default value for C<max_outstanding> is very large, so there is no
		1750	practical limit on the number of outstanding requests.
1216		1751
1217	=back	1752	=back
1218		1753
1219	=head3 STATISTICAL INFORMATION	1754	=head3 STATISTICAL INFORMATION
1220		1755
…		…
1240	Returns the number of requests currently in the pending state (executed,	1775	Returns the number of requests currently in the pending state (executed,
1241	but not yet processed by poll_cb).	1776	but not yet processed by poll_cb).
1242		1777
1243	=back	1778	=back
1244		1779
		1780	=head3 MISCELLANEOUS FUNCTIONS
		1781
		1782	IO::AIO implements some functions that might be useful, but are not
		1783	asynchronous.
		1784
		1785	=over 4
		1786
		1787	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1788
		1789	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1790	but is blocking (this makes most sense if you know the input data is
		1791	likely cached already and the output filehandle is set to non-blocking
		1792	operations).
		1793
		1794	Returns the number of bytes copied, or C<-1> on error.
		1795
		1796	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1797
		1798	Simply calls the C<posix_fadvise> function (see its
		1799	manpage for details). The following advice constants are
		1800	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1801	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1802	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1803
		1804	On systems that do not implement C<posix_fadvise>, this function returns
		1805	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1806
		1807	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1808
		1809	Simply calls the C<posix_madvise> function (see its
		1810	manpage for details). The following advice constants are
		1811	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1812	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1813
		1814	On systems that do not implement C<posix_madvise>, this function returns
		1815	ENOSYS, otherwise the return value of C<posix_madvise>.
		1816
		1817	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1818
		1819	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1820	$scalar (see its manpage for details). The following protect
		1821	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1822	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1823
		1824	On systems that do not implement C<mprotect>, this function returns
		1825	ENOSYS, otherwise the return value of C<mprotect>.
		1826
		1827	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1828
		1829	Memory-maps a file (or anonymous memory range) and attaches it to the
		1830	given C<$scalar>, which will act like a string scalar.
		1831
		1832	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1833	change the string length, and most read-only operations such as copying it
		1834	or searching it with regexes and so on.
		1835
		1836	Anything else is unsafe and will, at best, result in memory leaks.
		1837
		1838	The memory map associated with the C<$scalar> is automatically removed
		1839	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1840	C<IO::AIO::munmap> functions are called.
		1841
		1842	This calls the C<mmap>(2) function internally. See your system's manual
		1843	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1844
		1845	The C<$length> must be larger than zero and smaller than the actual
		1846	filesize.
		1847
		1848	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1849	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1850
		1851	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1852	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1853	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1854	(which is set to C<MAP_ANON> if your system only provides this
		1855	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1856	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1857	C<IO::AIO::MAP_NONBLOCK>
		1858
		1859	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1860
		1861	C<$offset> is the offset from the start of the file - it generally must be
		1862	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1863
		1864	Example:
		1865
		1866	use Digest::MD5;
		1867	use IO::AIO;
		1868
		1869	open my $fh, "<verybigfile"
		1870	or die "$!";
		1871
		1872	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1873	or die "verybigfile: $!";
		1874
		1875	my $fast_md5 = md5 $data;
		1876
		1877	=item IO::AIO::munmap $scalar
		1878
		1879	Removes a previous mmap and undefines the C<$scalar>.
		1880
		1881	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1882
		1883	Calls the C<munlock> function, undoing the effects of a previous
		1884	C<aio_mlock> call (see its description for details).
		1885
		1886	=item IO::AIO::munlockall
		1887
		1888	Calls the C<munlockall> function.
		1889
		1890	On systems that do not implement C<munlockall>, this function returns
		1891	ENOSYS, otherwise the return value of C<munlockall>.
		1892
		1893	=back
		1894
1245	=cut	1895	=cut
1246		1896
1247	# support function to convert a fd into a perl filehandle
1248	sub _fd2fh {
1249	return undef if $_[0] < 0;
1250
1251	# try to generate nice filehandles
1252	my $sym = "IO::AIO::fd#$_[0]";
1253	local *$sym;
1254
1255	open *$sym, "+<&=$_[0]" # usually works under any unix
1256	or open *$sym, "<&=$_[0]" # cygwin needs this
1257	or open *$sym, ">&=$_[0]" # or this
1258	or return undef;
1259
1260	*$sym
1261	}
1262
1263	min_parallel 8;	1897	min_parallel 8;
1264		1898
1265	END { flush }	1899	END { flush }
1266		1900
1267	1;	1901	1;
1268		1902
		1903	=head1 EVENT LOOP INTEGRATION
		1904
		1905	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1906	automatically into many event loops:
		1907
		1908	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1909	use AnyEvent::AIO;
		1910
		1911	You can also integrate IO::AIO manually into many event loops, here are
		1912	some examples of how to do this:
		1913
		1914	# EV integration
		1915	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1916
		1917	# Event integration
		1918	Event->io (fd => IO::AIO::poll_fileno,
		1919	poll => 'r',
		1920	cb => \&IO::AIO::poll_cb);
		1921
		1922	# Glib/Gtk2 integration
		1923	add_watch Glib::IO IO::AIO::poll_fileno,
		1924	in => sub { IO::AIO::poll_cb; 1 };
		1925
		1926	# Tk integration
		1927	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1928	readable => \&IO::AIO::poll_cb);
		1929
		1930	# Danga::Socket integration
		1931	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1932	\&IO::AIO::poll_cb);
		1933
1269	=head2 FORK BEHAVIOUR	1934	=head2 FORK BEHAVIOUR
1270		1935
1271	This module should do "the right thing" when the process using it forks:	1936	Usage of pthreads in a program changes the semantics of fork
		1937	considerably. Specifically, only async-safe functions can be called after
		1938	fork. Perl doesn't know about this, so in general, you cannot call fork
		1939	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		1940	pthreads, so this applies, but many other extensions and (for inexplicable
		1941	reasons) perl itself often is linked against pthreads, so this limitation
		1942	applies to quite a lot of perls.
1272		1943
1273	Before the fork, IO::AIO enters a quiescent state where no requests	1944	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1274	can be added in other threads and no results will be processed. After	1945	only works in the process that loaded it. Forking is fully supported, but
1275	the fork the parent simply leaves the quiescent state and continues	1946	using IO::AIO in the child is not.
1276	request/result processing, while the child frees the request/result queue
1277	(so that the requests started before the fork will only be handled in the
1278	parent). Threads will be started on demand until the limit set in the
1279	parent process has been reached again.
1280		1947
1281	In short: the parent will, after a short pause, continue as if fork had	1948	You might get around by not I<using> IO::AIO before (or after)
1282	not been called, while the child will act as if IO::AIO has not been used	1949	forking. You could also try to call the L<IO::AIO::reinit> function in the
1283	yet.	1950	child:
		1951
		1952	=over 4
		1953
		1954	=item IO::AIO::reinit
		1955
		1956	Abandons all current requests and I/O threads and simply reinitialises all
		1957	data structures. This is not an operation supported by any standards, but
		1958	happens to work on GNU/Linux and some newer BSD systems.
		1959
		1960	The only reasonable use for this function is to call it after forking, if
		1961	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1962	the process will result in undefined behaviour. Calling it at any time
		1963	will also result in any undefined (by POSIX) behaviour.
		1964
		1965	=back
1284		1966
1285	=head2 MEMORY USAGE	1967	=head2 MEMORY USAGE
1286		1968
1287	Per-request usage:	1969	Per-request usage:
1288		1970
…		…
1290	bytes of memory. In addition, stat requests need a stat buffer (possibly	1972	bytes of memory. In addition, stat requests need a stat buffer (possibly
1291	a few hundred bytes), readdir requires a result buffer and so on. Perl	1973	a few hundred bytes), readdir requires a result buffer and so on. Perl
1292	scalars and other data passed into aio requests will also be locked and	1974	scalars and other data passed into aio requests will also be locked and
1293	will consume memory till the request has entered the done state.	1975	will consume memory till the request has entered the done state.
1294		1976
1295	This is now awfully much, so queuing lots of requests is not usually a	1977	This is not awfully much, so queuing lots of requests is not usually a
1296	problem.	1978	problem.
1297		1979
1298	Per-thread usage:	1980	Per-thread usage:
1299		1981
1300	In the execution phase, some aio requests require more memory for	1982	In the execution phase, some aio requests require more memory for
…		…
1305		1987
1306	Known bugs will be fixed in the next release.	1988	Known bugs will be fixed in the next release.
1307		1989
1308	=head1 SEE ALSO	1990	=head1 SEE ALSO
1309		1991
1310	L<Coro::AIO>.	1992	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1993	more natural syntax.
1311		1994
1312	=head1 AUTHOR	1995	=head1 AUTHOR
1313		1996
1314	Marc Lehmann <schmorp@schmorp.de>	1997	Marc Lehmann <schmorp@schmorp.de>
1315	http://home.schmorp.de/	1998	http://home.schmorp.de/

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