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Revision 1.105 by root, Sun Mar 25 00:20:27 2007 UTC vs.
Revision 1.190 by root, Thu May 19 22:42:20 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
…		…
62	etc.), but can also be used to easily do operations in parallel that are	42	etc.), but can also be used to easily do operations in parallel that are
63	normally done sequentially, e.g. stat'ing many files, which is much faster	43	normally done sequentially, e.g. stat'ing many files, which is much faster
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 example	47	While most of this works on all types of file descriptors (for
68	sockets), using these functions on file descriptors that support	48	example sockets), using these functions on file descriptors that
69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or	49	support nonblocking operation (again, sockets, pipes etc.) is
70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop	50	very inefficient. Use an event loop for that (such as the L<EV>
71	for that (such as the L<Event|Event> module): IO::AIO will naturally fit	51	module): IO::AIO will naturally fit into such an event loop itself.
72	into such an event loop itself.
73		52
74	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
75	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
76	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
77	to perl. In the future, this module might make use of the native aio	56	to perl. In the future, this module might make use of the native aio
…		…
79	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
80	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
81	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
82	using threads anyway.	61	using threads anyway.
83		62
84	Although the module will work with in the presence of other (Perl-)	63	Although the module will work in the presence of other (Perl-) threads,
85	threads, it is currently not reentrant in any way, so use appropriate	64	it is currently not reentrant in any way, so use appropriate locking
86	locking yourself, always call C<poll_cb> from within the same thread, or	65	yourself, always call C<poll_cb> from within the same thread, or never
87	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
88		67
89	=head2 EXAMPLE	68	=head2 EXAMPLE
90		69
91	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
92	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
93		72
94	use Fcntl;	73	use Fcntl;
95	use Event;	74	use EV;
96	use IO::AIO;	75	use IO::AIO;
97		76
98	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
99	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
100	poll => 'r',
101	cb => \&IO::AIO::poll_cb);
102		79
103	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105	my $fh = shift	82	my $fh = shift
106	or die "error while opening: $!";	83	or die "error while opening: $!";
107		84
108	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
109	my $size = -s $fh;	86	my $size = -s $fh;
…		…
118		95
119	# file contents now in $contents	96	# file contents now in $contents
120	print $contents;	97	print $contents;
121		98
122	# exit event loop and program	99	# exit event loop and program
123	Event::unloop;	100	EV::unloop;
124	};	101	};
125	};	102	};
126		103
127	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
128	# check for sockets etc. etc.	105	# check for sockets etc. etc.
129		106
130	# process events as long as there are some:	107	# process events as long as there are some:
131	Event::loop;	108	EV::loop;
132		109
133	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
134		111
135	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
136	directly visible to Perl.	113	directly visible to Perl.
…		…
184		161
185	=cut	162	=cut
186		163
187	package IO::AIO;	164	package IO::AIO;
188		165
189	no warnings;	166	use Carp ();
190	use strict 'vars';	167
		168	use common::sense;
191		169
192	use base 'Exporter';	170	use base 'Exporter';
193		171
194	BEGIN {	172	BEGIN {
195	our $VERSION = '2.33';	173	our $VERSION = '3.8';
196		174
197	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
198	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
199	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
		178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		179	aio_rename aio_link aio_move aio_copy aio_group
200	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir);	180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		181	aio_chmod aio_utime aio_truncate
		182	aio_msync aio_mtouch aio_mlock aio_mlockall
		183	aio_statvfs);
		184
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	187	min_parallel max_parallel max_idle idle_timeout
204	nreqs nready npending nthreads	188	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	189	max_poll_time max_poll_reqs
		190	sendfile fadvise madvise
		191	mmap munmap munlock munlockall);
		192
		193	push @AIO_REQ, qw(aio_busy); # not exported
206		194
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		196
209	require XSLoader;	197	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
211	}	199	}
212		200
213	=head1 FUNCTIONS	201	=head1 FUNCTIONS
		202
		203	=head2 QUICK OVERVIEW
		204
		205	This section simply lists the prototypes of the most important functions
		206	for quick reference. See the following sections for function-by-function
		207	documentation.
		208
		209	aio_open $pathname, $flags, $mode, $callback->($fh)
		210	aio_close $fh, $callback->($status)
		211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		214	aio_readahead $fh,$offset,$length, $callback->($retval)
		215	aio_stat $fh_or_path, $callback->($status)
		216	aio_lstat $fh, $callback->($status)
		217	aio_statvfs $fh_or_path, $callback->($statvfs)
		218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		220	aio_truncate $fh_or_path, $offset, $callback->($status)
		221	aio_chmod $fh_or_path, $mode, $callback->($status)
		222	aio_unlink $pathname, $callback->($status)
		223	aio_mknod $path, $mode, $dev, $callback->($status)
		224	aio_link $srcpath, $dstpath, $callback->($status)
		225	aio_symlink $srcpath, $dstpath, $callback->($status)
		226	aio_readlink $path, $callback->($link)
		227	aio_rename $srcpath, $dstpath, $callback->($status)
		228	aio_mkdir $pathname, $mode, $callback->($status)
		229	aio_rmdir $pathname, $callback->($status)
		230	aio_readdir $pathname, $callback->($entries)
		231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		234	aio_load $path, $data, $callback->($status)
		235	aio_copy $srcpath, $dstpath, $callback->($status)
		236	aio_move $srcpath, $dstpath, $callback->($status)
		237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		238	aio_rmtree $path, $callback->($status)
		239	aio_sync $callback->($status)
		240	aio_fsync $fh, $callback->($status)
		241	aio_fdatasync $fh, $callback->($status)
		242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		243	aio_pathsync $path, $callback->($status)
		244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		247	aio_mlockall $flags, $callback->($status)
		248	aio_group $callback->(...)
		249	aio_nop $callback->()
		250
		251	$prev_pri = aioreq_pri [$pri]
		252	aioreq_nice $pri_adjust
		253
		254	IO::AIO::poll_wait
		255	IO::AIO::poll_cb
		256	IO::AIO::poll
		257	IO::AIO::flush
		258	IO::AIO::max_poll_reqs $nreqs
		259	IO::AIO::max_poll_time $seconds
		260	IO::AIO::min_parallel $nthreads
		261	IO::AIO::max_parallel $nthreads
		262	IO::AIO::max_idle $nthreads
		263	IO::AIO::idle_timeout $seconds
		264	IO::AIO::max_outstanding $maxreqs
		265	IO::AIO::nreqs
		266	IO::AIO::nready
		267	IO::AIO::npending
		268
		269	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		270	IO::AIO::fadvise $fh, $offset, $len, $advice
		271	IO::AIO::madvise $scalar, $offset, $length, $advice
		272	IO::AIO::mprotect $scalar, $offset, $length, $protect
		273	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		274	IO::AIO::munlockall
214		275
215	=head2 AIO REQUEST FUNCTIONS	276	=head2 AIO REQUEST FUNCTIONS
216		277
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	278	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	279	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	280	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	281	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	282	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	283	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	284	syscall has been executed asynchronously.
224		285
225	All functions expecting a filehandle keep a copy of the filehandle	286	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	287	internally until the request has finished.
227		288
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	302	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)	303	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	304	use something else to ensure your scalar has the correct contents.
244		305
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	307	handles correctly whether it is set or not.
247		308
248	=over 4	309	=over 4
249		310
250	=item $prev_pri = aioreq_pri [$pri]	311	=item $prev_pri = aioreq_pri [$pri]
251		312
…		…
271	aio_read $_[0], ..., sub {	332	aio_read $_[0], ..., sub {
272	...	333	...
273	};	334	};
274	};	335	};
275		336
		337
276	=item aioreq_nice $pri_adjust	338	=item aioreq_nice $pri_adjust
277		339
278	Similar to C<aioreq_pri>, but subtracts the given value from the current	340	Similar to C<aioreq_pri>, but subtracts the given value from the current
279	priority, so the effect is cumulative.	341	priority, so the effect is cumulative.
		342
280		343
281	=item aio_open $pathname, $flags, $mode, $callback->($fh)	344	=item aio_open $pathname, $flags, $mode, $callback->($fh)
282		345
283	Asynchronously open or create a file and call the callback with a newly	346	Asynchronously open or create a file and call the callback with a newly
284	created filehandle for the file.	347	created filehandle for the file.
…		…
296	by the umask in effect then the request is being executed, so better never	359	by the umask in effect then the request is being executed, so better never
297	change the umask.	360	change the umask.
298		361
299	Example:	362	Example:
300		363
301	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
302	if ($_[0]) {	365	if ($_[0]) {
303	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
304	...	367	...
305	} else {	368	} else {
306	die "open failed: $!\n";	369	die "open failed: $!\n";
307	}	370	}
308	};	371	};
309		372
		373
310	=item aio_close $fh, $callback->($status)	374	=item aio_close $fh, $callback->($status)
311		375
312	Asynchronously close a file and call the callback with the result	376	Asynchronously close a file and call the callback with the result
313	code. I<WARNING:> although accepted, you should not pass in a perl	377	code.
314	filehandle here, as perl will likely close the file descriptor another
315	time when the filehandle is destroyed. Normally, you can safely call perls
316	C<close> or just let filehandles go out of scope.
317		378
318	This is supposed to be a bug in the API, so that might change. It's	379	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
319	therefore best to avoid this function.	380	closing the file descriptor associated with the filehandle itself.
		381
		382	Therefore, C<aio_close> will not close the filehandle - instead it will
		383	use dup2 to overwrite the file descriptor with the write-end of a pipe
		384	(the pipe fd will be created on demand and will be cached).
		385
		386	Or in other words: the file descriptor will be closed, but it will not be
		387	free for reuse until the perl filehandle is closed.
		388
		389	=cut
320		390
321	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	391	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322		392
323	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	393	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
324		394
325	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	395	Reads or writes C<$length> bytes from or to the specified C<$fh> and
326	into the scalar given by C<data> and offset C<dataoffset> and calls the	396	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
327	callback without the actual number of bytes read (or -1 on error, just	397	and calls the callback without the actual number of bytes read (or -1 on
328	like the syscall).	398	error, just like the syscall).
		399
		400	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		401	offset plus the actual number of bytes read.
		402
		403	If C<$offset> is undefined, then the current file descriptor offset will
		404	be used (and updated), otherwise the file descriptor offset will not be
		405	changed by these calls.
		406
		407	If C<$length> is undefined in C<aio_write>, use the remaining length of
		408	C<$data>.
		409
		410	If C<$dataoffset> is less than zero, it will be counted from the end of
		411	C<$data>.
329		412
330	The C<$data> scalar I<MUST NOT> be modified in any way while the request	413	The C<$data> scalar I<MUST NOT> be modified in any way while the request
331	is outstanding. Modifying it can result in segfaults or WW3 (if the	414	is outstanding. Modifying it can result in segfaults or World War III (if
332	necessary/optional hardware is installed).	415	the necessary/optional hardware is installed).
333		416
334	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	417	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
335	offset C<0> within the scalar:	418	offset C<0> within the scalar:
336		419
337	aio_read $fh, 7, 15, $buffer, 0, sub {	420	aio_read $fh, 7, 15, $buffer, 0, sub {
338	$_[0] > 0 or die "read error: $!";	421	$_[0] > 0 or die "read error: $!";
339	print "read $_[0] bytes: <$buffer>\n";	422	print "read $_[0] bytes: <$buffer>\n";
340	};	423	};
		424
341		425
342	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	426	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
343		427
344	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	428	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
345	reading at byte offset C<$in_offset>, and starts writing at the current	429	reading at byte offset C<$in_offset>, and starts writing at the current
346	file offset of C<$out_fh>. Because of that, it is not safe to issue more	430	file offset of C<$out_fh>. Because of that, it is not safe to issue more
347	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	431	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
348	other.	432	other.
349		433
		434	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		435	are written, and there is no way to find out how many bytes have been read
		436	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
		437	bytes written to C<$out_fh>. Only if the result value equals C<$length>
		438	one can assume that C<$length> bytes have been read.
		439
		440	Unlike with other C<aio_> functions, it makes a lot of sense to use
		441	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		442	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		443	the socket I/O will be non-blocking. Note, however, that you can run into
		444	a trap where C<aio_sendfile> reads some data with readahead, then fails
		445	to write all data, and when the socket is ready the next time, the data
		446	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		447	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		448	much better.
		449
350	This call tries to make use of a native C<sendfile> syscall to provide	450	This call tries to make use of a native C<sendfile> syscall to provide
351	zero-copy operation. For this to work, C<$out_fh> should refer to a	451	zero-copy operation. For this to work, C<$out_fh> should refer to a
352	socket, and C<$in_fh> should refer to mmap'able file.	452	socket, and C<$in_fh> should refer to an mmap'able file.
353		453
354	If the native sendfile call fails or is not implemented, it will be	454	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		455	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
355	emulated, so you can call C<aio_sendfile> on any type of filehandle	456	it will be emulated, so you can call C<aio_sendfile> on any type of
356	regardless of the limitations of the operating system.	457	filehandle regardless of the limitations of the operating system.
357		458
358	Please note, however, that C<aio_sendfile> can read more bytes from
359	C<$in_fh> than are written, and there is no way to find out how many
360	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
361	provides the number of bytes written to C<$out_fh>. Only if the result
362	value equals C<$length> one can assume that C<$length> bytes have been
363	read.
364		459
365	=item aio_readahead $fh,$offset,$length, $callback->($retval)	460	=item aio_readahead $fh,$offset,$length, $callback->($retval)
366		461
367	C<aio_readahead> populates the page cache with data from a file so that	462	C<aio_readahead> populates the page cache with data from a file so that
368	subsequent reads from that file will not block on disk I/O. The C<$offset>	463	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
374	file. The current file offset of the file is left unchanged.	469	file. The current file offset of the file is left unchanged.
375		470
376	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	471	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
377	emulated by simply reading the data, which would have a similar effect.	472	emulated by simply reading the data, which would have a similar effect.
378		473
		474
379	=item aio_stat $fh_or_path, $callback->($status)	475	=item aio_stat $fh_or_path, $callback->($status)
380		476
381	=item aio_lstat $fh, $callback->($status)	477	=item aio_lstat $fh, $callback->($status)
382		478
383	Works like perl's C<stat> or C<lstat> in void context. The callback will	479	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
388	for an explanation.	484	for an explanation.
389		485
390	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	486	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
391	error when stat'ing a large file, the results will be silently truncated	487	error when stat'ing a large file, the results will be silently truncated
392	unless perl itself is compiled with large file support.	488	unless perl itself is compiled with large file support.
		489
		490	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		491	following constants and functions (if not implemented, the constants will
		492	be C<0> and the functions will either C<croak> or fall back on traditional
		493	behaviour).
		494
		495	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		496	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		497	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
393		498
394	Example: Print the length of F</etc/passwd>:	499	Example: Print the length of F</etc/passwd>:
395		500
396	aio_stat "/etc/passwd", sub {	501	aio_stat "/etc/passwd", sub {
397	$_[0] and die "stat failed: $!";	502	$_[0] and die "stat failed: $!";
398	print "size is ", -s _, "\n";	503	print "size is ", -s _, "\n";
399	};	504	};
400		505
		506
		507	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		508
		509	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		510	whether a file handle or path was passed.
		511
		512	On success, the callback is passed a hash reference with the following
		513	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		514	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		515	is passed.
		516
		517	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		518	C<ST_NOSUID>.
		519
		520	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		521	their correct value when available, or to C<0> on systems that do
		522	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		523	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		524	C<ST_NODIRATIME> and C<ST_RELATIME>.
		525
		526	Example: stat C</wd> and dump out the data if successful.
		527
		528	aio_statvfs "/wd", sub {
		529	my $f = $_[0]
		530	or die "statvfs: $!";
		531
		532	use Data::Dumper;
		533	say Dumper $f;
		534	};
		535
		536	# result:
		537	{
		538	bsize => 1024,
		539	bfree => 4333064312,
		540	blocks => 10253828096,
		541	files => 2050765568,
		542	flag => 4096,
		543	favail => 2042092649,
		544	bavail => 4333064312,
		545	ffree => 2042092649,
		546	namemax => 255,
		547	frsize => 1024,
		548	fsid => 1810
		549	}
		550
		551
		552	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		553
		554	Works like perl's C<utime> function (including the special case of $atime
		555	and $mtime being undef). Fractional times are supported if the underlying
		556	syscalls support them.
		557
		558	When called with a pathname, uses utimes(2) if available, otherwise
		559	utime(2). If called on a file descriptor, uses futimes(2) if available,
		560	otherwise returns ENOSYS, so this is not portable.
		561
		562	Examples:
		563
		564	# set atime and mtime to current time (basically touch(1)):
		565	aio_utime "path", undef, undef;
		566	# set atime to current time and mtime to beginning of the epoch:
		567	aio_utime "path", time, undef; # undef==0
		568
		569
		570	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		571
		572	Works like perl's C<chown> function, except that C<undef> for either $uid
		573	or $gid is being interpreted as "do not change" (but -1 can also be used).
		574
		575	Examples:
		576
		577	# same as "chown root path" in the shell:
		578	aio_chown "path", 0, -1;
		579	# same as above:
		580	aio_chown "path", 0, undef;
		581
		582
		583	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		584
		585	Works like truncate(2) or ftruncate(2).
		586
		587
		588	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		589
		590	Works like perl's C<chmod> function.
		591
		592
401	=item aio_unlink $pathname, $callback->($status)	593	=item aio_unlink $pathname, $callback->($status)
402		594
403	Asynchronously unlink (delete) a file and call the callback with the	595	Asynchronously unlink (delete) a file and call the callback with the
404	result code.	596	result code.
405		597
		598
406	=item aio_mknod $path, $mode, $dev, $callback->($status)	599	=item aio_mknod $path, $mode, $dev, $callback->($status)
407		600
408	[EXPERIMENTAL]	601	[EXPERIMENTAL]
409		602
410	Asynchronously create a device node (or fifo). See mknod(2).	603	Asynchronously create a device node (or fifo). See mknod(2).
411		604
412	The only (POSIX-) portable way of calling this function is:	605	The only (POSIX-) portable way of calling this function is:
413		606
414	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	607	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		608
		609	See C<aio_stat> for info about some potentially helpful extra constants
		610	and functions.
415		611
416	=item aio_link $srcpath, $dstpath, $callback->($status)	612	=item aio_link $srcpath, $dstpath, $callback->($status)
417		613
418	Asynchronously create a new link to the existing object at C<$srcpath> at	614	Asynchronously create a new link to the existing object at C<$srcpath> at
419	the path C<$dstpath> and call the callback with the result code.	615	the path C<$dstpath> and call the callback with the result code.
420		616
		617
421	=item aio_symlink $srcpath, $dstpath, $callback->($status)	618	=item aio_symlink $srcpath, $dstpath, $callback->($status)
422		619
423	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	620	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
424	the path C<$dstpath> and call the callback with the result code.	621	the path C<$dstpath> and call the callback with the result code.
		622
425		623
426	=item aio_readlink $path, $callback->($link)	624	=item aio_readlink $path, $callback->($link)
427		625
428	Asynchronously read the symlink specified by C<$path> and pass it to	626	Asynchronously read the symlink specified by C<$path> and pass it to
429	the callback. If an error occurs, nothing or undef gets passed to the	627	the callback. If an error occurs, nothing or undef gets passed to the
430	callback.	628	callback.
431		629
		630
432	=item aio_rename $srcpath, $dstpath, $callback->($status)	631	=item aio_rename $srcpath, $dstpath, $callback->($status)
433		632
434	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	633	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
435	rename(2) and call the callback with the result code.	634	rename(2) and call the callback with the result code.
		635
436		636
437	=item aio_mkdir $pathname, $mode, $callback->($status)	637	=item aio_mkdir $pathname, $mode, $callback->($status)
438		638
439	Asynchronously mkdir (create) a directory and call the callback with	639	Asynchronously mkdir (create) a directory and call the callback with
440	the result code. C<$mode> will be modified by the umask at the time the	640	the result code. C<$mode> will be modified by the umask at the time the
441	request is executed, so do not change your umask.	641	request is executed, so do not change your umask.
442		642
		643
443	=item aio_rmdir $pathname, $callback->($status)	644	=item aio_rmdir $pathname, $callback->($status)
444		645
445	Asynchronously rmdir (delete) a directory and call the callback with the	646	Asynchronously rmdir (delete) a directory and call the callback with the
446	result code.	647	result code.
		648
447		649
448	=item aio_readdir $pathname, $callback->($entries)	650	=item aio_readdir $pathname, $callback->($entries)
449		651
450	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	652	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
451	directory (i.e. opendir + readdir + closedir). The entries will not be	653	directory (i.e. opendir + readdir + closedir). The entries will not be
452	sorted, and will B<NOT> include the C<.> and C<..> entries.	654	sorted, and will B<NOT> include the C<.> and C<..> entries.
453		655
454	The callback a single argument which is either C<undef> or an array-ref	656	The callback is passed a single argument which is either C<undef> or an
455	with the filenames.	657	array-ref with the filenames.
		658
		659
		660	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		661
		662	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		663	behaviour and output format. In case of an error, C<$entries> will be
		664	C<undef>.
		665
		666	The flags are a combination of the following constants, ORed together (the
		667	flags will also be passed to the callback, possibly modified):
		668
		669	=over 4
		670
		671	=item IO::AIO::READDIR_DENTS
		672
		673	When this flag is off, then the callback gets an arrayref consisting of
		674	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		675	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		676	entry in more detail.
		677
		678	C<$name> is the name of the entry.
		679
		680	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		681
		682	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		683	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		684	C<IO::AIO::DT_WHT>.
		685
		686	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		687	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		688	scalars are read-only: you can not modify them.
		689
		690	C<$inode> is the inode number (which might not be exact on systems with 64
		691	bit inode numbers and 32 bit perls). This field has unspecified content on
		692	systems that do not deliver the inode information.
		693
		694	=item IO::AIO::READDIR_DIRS_FIRST
		695
		696	When this flag is set, then the names will be returned in an order where
		697	likely directories come first. This is useful when you need to quickly
		698	find directories, or you want to find all directories while avoiding to
		699	stat() each entry.
		700
		701	If the system returns type information in readdir, then this is used
		702	to find directories directly. Otherwise, likely directories are files
		703	beginning with ".", or otherwise files with no dots, of which files with
		704	short names are tried first.
		705
		706	=item IO::AIO::READDIR_STAT_ORDER
		707
		708	When this flag is set, then the names will be returned in an order
		709	suitable for stat()'ing each one. That is, when you plan to stat()
		710	all files in the given directory, then the returned order will likely
		711	be fastest.
		712
		713	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		714	the likely dirs come first, resulting in a less optimal stat order.
		715
		716	=item IO::AIO::READDIR_FOUND_UNKNOWN
		717
		718	This flag should not be set when calling C<aio_readdirx>. Instead, it
		719	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		720	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		721	C<$type>'s are known, which can be used to speed up some algorithms.
		722
		723	=back
		724
456		725
457	=item aio_load $path, $data, $callback->($status)	726	=item aio_load $path, $data, $callback->($status)
458		727
459	This is a composite request that tries to fully load the given file into	728	This is a composite request that tries to fully load the given file into
460	memory. Status is the same as with aio_read.	729	memory. Status is the same as with aio_read.
461		730
462	=cut	731	=cut
463		732
464	sub aio_load($$;$) {	733	sub aio_load($$;$) {
465	aio_block {
466	my ($path, undef, $cb) = @_;	734	my ($path, undef, $cb) = @_;
467	my $data = \$_[1];	735	my $data = \$_[1];
468		736
469	my $pri = aioreq_pri;	737	my $pri = aioreq_pri;
470	my $grp = aio_group $cb;	738	my $grp = aio_group $cb;
		739
		740	aioreq_pri $pri;
		741	add $grp aio_open $path, O_RDONLY, 0, sub {
		742	my $fh = shift
		743	or return $grp->result (-1);
471		744
472	aioreq_pri $pri;	745	aioreq_pri $pri;
473	add $grp aio_open $path, O_RDONLY, 0, sub {
474	my $fh = shift
475	or return $grp->result (-1);
476
477	aioreq_pri $pri;
478	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	746	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
479	$grp->result ($_[0]);	747	$grp->result ($_[0]);
480	};
481	};	748	};
482
483	$grp
484	}	749	};
		750
		751	$grp
485	}	752	}
486		753
487	=item aio_copy $srcpath, $dstpath, $callback->($status)	754	=item aio_copy $srcpath, $dstpath, $callback->($status)
488		755
489	Try to copy the I<file> (directories not supported as either source or	756	Try to copy the I<file> (directories not supported as either source or
490	destination) from C<$srcpath> to C<$dstpath> and call the callback with	757	destination) from C<$srcpath> to C<$dstpath> and call the callback with
491	the C<0> (error) or C<-1> ok.	758	a status of C<0> (ok) or C<-1> (error, see C<$!>).
492		759
493	This is a composite request that it creates the destination file with	760	This is a composite request that creates the destination file with
494	mode 0200 and copies the contents of the source file into it using	761	mode 0200 and copies the contents of the source file into it using
495	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	762	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
496	uid/gid, in that order.	763	uid/gid, in that order.
497		764
498	If an error occurs, the partial destination file will be unlinked, if	765	If an error occurs, the partial destination file will be unlinked, if
…		…
500	errors are being ignored.	767	errors are being ignored.
501		768
502	=cut	769	=cut
503		770
504	sub aio_copy($$;$) {	771	sub aio_copy($$;$) {
505	aio_block {
506	my ($src, $dst, $cb) = @_;	772	my ($src, $dst, $cb) = @_;
507		773
508	my $pri = aioreq_pri;	774	my $pri = aioreq_pri;
509	my $grp = aio_group $cb;	775	my $grp = aio_group $cb;
510		776
511	aioreq_pri $pri;	777	aioreq_pri $pri;
512	add $grp aio_open $src, O_RDONLY, 0, sub {	778	add $grp aio_open $src, O_RDONLY, 0, sub {
513	if (my $src_fh = $_[0]) {	779	if (my $src_fh = $_[0]) {
514	my @stat = stat $src_fh;	780	my @stat = stat $src_fh; # hmm, might block over nfs?
515		781
516	aioreq_pri $pri;	782	aioreq_pri $pri;
517	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	783	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
518	if (my $dst_fh = $_[0]) {	784	if (my $dst_fh = $_[0]) {
519	aioreq_pri $pri;	785	aioreq_pri $pri;
520	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	786	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
521	if ($_[0] == $stat[7]) {	787	if ($_[0] == $stat[7]) {
522	$grp->result (0);	788	$grp->result (0);
523	close $src_fh;	789	close $src_fh;
524		790
525	# those should not normally block. should. should.
526	utime $stat[8], $stat[9], $dst;
527	chmod $stat[2] & 07777, $dst_fh;
528	chown $stat[4], $stat[5], $dst_fh;
529	close $dst_fh;
530	} else {	791	my $ch = sub {
531	$grp->result (-1);
532	close $src_fh;
533	close $dst_fh;
534
535	aioreq $pri;	792	aioreq_pri $pri;
		793	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		794	aioreq_pri $pri;
		795	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		796	aioreq_pri $pri;
536	add $grp aio_unlink $dst;	797	add $grp aio_close $dst_fh;
		798	}
		799	};
537	}	800	};
		801
		802	aioreq_pri $pri;
		803	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		804	if ($_[0] < 0 && $! == ENOSYS) {
		805	aioreq_pri $pri;
		806	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		807	} else {
		808	$ch->();
		809	}
		810	};
		811	} else {
		812	$grp->result (-1);
		813	close $src_fh;
		814	close $dst_fh;
		815
		816	aioreq $pri;
		817	add $grp aio_unlink $dst;
538	};	818	}
539	} else {
540	$grp->result (-1);
541	}	819	};
		820	} else {
		821	$grp->result (-1);
542	},	822	}
543
544	} else {
545	$grp->result (-1);
546	}	823	},
		824
		825	} else {
		826	$grp->result (-1);
547	};	827	}
548
549	$grp
550	}	828	};
		829
		830	$grp
551	}	831	}
552		832
553	=item aio_move $srcpath, $dstpath, $callback->($status)	833	=item aio_move $srcpath, $dstpath, $callback->($status)
554		834
555	Try to move the I<file> (directories not supported as either source or	835	Try to move the I<file> (directories not supported as either source or
556	destination) from C<$srcpath> to C<$dstpath> and call the callback with	836	destination) from C<$srcpath> to C<$dstpath> and call the callback with
557	the C<0> (error) or C<-1> ok.	837	a status of C<0> (ok) or C<-1> (error, see C<$!>).
558		838
559	This is a composite request that tries to rename(2) the file first. If	839	This is a composite request that tries to rename(2) the file first; if
560	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	840	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
561	that is successful, unlinking the C<$srcpath>.	841	that is successful, unlinks the C<$srcpath>.
562		842
563	=cut	843	=cut
564		844
565	sub aio_move($$;$) {	845	sub aio_move($$;$) {
566	aio_block {
567	my ($src, $dst, $cb) = @_;	846	my ($src, $dst, $cb) = @_;
568		847
569	my $pri = aioreq_pri;	848	my $pri = aioreq_pri;
570	my $grp = aio_group $cb;	849	my $grp = aio_group $cb;
571		850
572	aioreq_pri $pri;	851	aioreq_pri $pri;
573	add $grp aio_rename $src, $dst, sub {	852	add $grp aio_rename $src, $dst, sub {
574	if ($_[0] && $! == EXDEV) {	853	if ($_[0] && $! == EXDEV) {
575	aioreq_pri $pri;	854	aioreq_pri $pri;
576	add $grp aio_copy $src, $dst, sub {	855	add $grp aio_copy $src, $dst, sub {
577	$grp->result ($_[0]);
578
579	if (!$_[0]) {
580	aioreq_pri $pri;
581	add $grp aio_unlink $src;
582	}
583	};
584	} else {
585	$grp->result ($_[0]);	856	$grp->result ($_[0]);
		857
		858	if (!$_[0]) {
		859	aioreq_pri $pri;
		860	add $grp aio_unlink $src;
		861	}
586	}	862	};
		863	} else {
		864	$grp->result ($_[0]);
587	};	865	}
588
589	$grp
590	}	866	};
		867
		868	$grp
591	}	869	}
592		870
593	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	871	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
594		872
595	Scans a directory (similar to C<aio_readdir>) but additionally tries to	873	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
615		893
616	Implementation notes.	894	Implementation notes.
617		895
618	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	896	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
619		897
		898	If readdir returns file type information, then this is used directly to
		899	find directories.
		900
620	After reading the directory, the modification time, size etc. of the	901	Otherwise, after reading the directory, the modification time, size etc.
621	directory before and after the readdir is checked, and if they match (and	902	of the directory before and after the readdir is checked, and if they
622	isn't the current time), the link count will be used to decide how many	903	match (and isn't the current time), the link count will be used to decide
623	entries are directories (if >= 2). Otherwise, no knowledge of the number	904	how many entries are directories (if >= 2). Otherwise, no knowledge of the
624	of subdirectories will be assumed.	905	number of subdirectories will be assumed.
625		906
626	Then entries will be sorted into likely directories (everything without	907	Then entries will be sorted into likely directories a non-initial dot
627	a non-initial dot currently) and likely non-directories (everything	908	currently) and likely non-directories (see C<aio_readdirx>). Then every
628	else). Then every entry plus an appended C</.> will be C<stat>'ed,	909	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
629	likely directories first. If that succeeds, it assumes that the entry	910	in order of their inode numbers. If that succeeds, it assumes that the
630	is a directory or a symlink to directory (which will be checked	911	entry is a directory or a symlink to directory (which will be checked
631	seperately). This is often faster than stat'ing the entry itself because	912	seperately). This is often faster than stat'ing the entry itself because
632	filesystems might detect the type of the entry without reading the inode	913	filesystems might detect the type of the entry without reading the inode
633	data (e.g. ext2fs filetype feature).	914	data (e.g. ext2fs filetype feature), even on systems that cannot return
		915	the filetype information on readdir.
634		916
635	If the known number of directories (link count - 2) has been reached, the	917	If the known number of directories (link count - 2) has been reached, the
636	rest of the entries is assumed to be non-directories.	918	rest of the entries is assumed to be non-directories.
637		919
638	This only works with certainty on POSIX (= UNIX) filesystems, which	920	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
643	directory counting heuristic.	925	directory counting heuristic.
644		926
645	=cut	927	=cut
646		928
647	sub aio_scandir($$;$) {	929	sub aio_scandir($$;$) {
648	aio_block {
649	my ($path, $maxreq, $cb) = @_;	930	my ($path, $maxreq, $cb) = @_;
650		931
651	my $pri = aioreq_pri;	932	my $pri = aioreq_pri;
652		933
653	my $grp = aio_group $cb;	934	my $grp = aio_group $cb;
654		935
655	$maxreq = 4 if $maxreq <= 0;	936	$maxreq = 4 if $maxreq <= 0;
656		937
657	# stat once	938	# stat once
		939	aioreq_pri $pri;
		940	add $grp aio_stat $path, sub {
		941	return $grp->result () if $_[0];
		942	my $now = time;
		943	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		944
		945	# read the directory entries
658	aioreq_pri $pri;	946	aioreq_pri $pri;
659	add $grp aio_stat $path, sub {	947	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		948	my $entries = shift
660	return $grp->result () if $_[0];	949	or return $grp->result ();
661	my $now = time;
662	my $hash1 = join ":", (stat _)[0,1,3,7,9];
663		950
664	# read the directory entries	951	# stat the dir another time
665	aioreq_pri $pri;	952	aioreq_pri $pri;
666	add $grp aio_readdir $path, sub {
667	my $entries = shift
668	or return $grp->result ();
669
670	# stat the dir another time
671	aioreq_pri $pri;
672	add $grp aio_stat $path, sub {	953	add $grp aio_stat $path, sub {
673	my $hash2 = join ":", (stat _)[0,1,3,7,9];	954	my $hash2 = join ":", (stat _)[0,1,3,7,9];
674		955
675	my $ndirs;	956	my $ndirs;
676		957
677	# take the slow route if anything looks fishy	958	# take the slow route if anything looks fishy
678	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	959	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
679	$ndirs = -1;	960	$ndirs = -1;
680	} else {	961	} else {
681	# if nlink == 2, we are finished	962	# if nlink == 2, we are finished
682	# on non-posix-fs's, we rely on nlink < 2	963	# for non-posix-fs's, we rely on nlink < 2
683	$ndirs = (stat _)[3] - 2	964	$ndirs = (stat _)[3] - 2
684	or return $grp->result ([], $entries);	965	or return $grp->result ([], $entries);
685	}	966	}
686		967
687	# sort into likely dirs and likely nondirs
688	# dirs == files without ".", short entries first
689	$entries = [map $_->[0],
690	sort { $b->[1] cmp $a->[1] }
691	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
692	@$entries];
693
694	my (@dirs, @nondirs);	968	my (@dirs, @nondirs);
695		969
696	my $statgrp = add $grp aio_group sub {	970	my $statgrp = add $grp aio_group sub {
697	$grp->result (\@dirs, \@nondirs);	971	$grp->result (\@dirs, \@nondirs);
698	};	972	};
699		973
700	limit $statgrp $maxreq;	974	limit $statgrp $maxreq;
701	feed $statgrp sub {	975	feed $statgrp sub {
702	return unless @$entries;	976	return unless @$entries;
703	my $entry = pop @$entries;	977	my $entry = shift @$entries;
704		978
705	aioreq_pri $pri;	979	aioreq_pri $pri;
706	add $statgrp aio_stat "$path/$entry/.", sub {	980	add $statgrp aio_stat "$path/$entry/.", sub {
707	if ($_[0] < 0) {	981	if ($_[0] < 0) {
708	push @nondirs, $entry;	982	push @nondirs, $entry;
709	} else {	983	} else {
710	# need to check for real directory	984	# need to check for real directory
711	aioreq_pri $pri;	985	aioreq_pri $pri;
712	add $statgrp aio_lstat "$path/$entry", sub {	986	add $statgrp aio_lstat "$path/$entry", sub {
713	if (-d _) {	987	if (-d _) {
714	push @dirs, $entry;	988	push @dirs, $entry;
715		989
716	unless (--$ndirs) {	990	unless (--$ndirs) {
717	push @nondirs, @$entries;	991	push @nondirs, @$entries;
718	feed $statgrp;	992	feed $statgrp;
719	}
720	} else {
721	push @nondirs, $entry;
722	}	993	}
		994	} else {
		995	push @nondirs, $entry;
723	}	996	}
724	}	997	}
725	};	998	}
726	};	999	};
727	};	1000	};
728	};	1001	};
729	};	1002	};
730
731	$grp
732	}	1003	};
		1004
		1005	$grp
733	}	1006	}
734		1007
735	=item aio_rmtree $path, $callback->($status)	1008	=item aio_rmtree $path, $callback->($status)
736		1009
737	Delete a directory tree starting (and including) C<$path>, return the	1010	Delete a directory tree starting (and including) C<$path>, return the
…		…
741		1014
742	=cut	1015	=cut
743		1016
744	sub aio_rmtree;	1017	sub aio_rmtree;
745	sub aio_rmtree($;$) {	1018	sub aio_rmtree($;$) {
746	aio_block {
747	my ($path, $cb) = @_;	1019	my ($path, $cb) = @_;
748		1020
749	my $pri = aioreq_pri;	1021	my $pri = aioreq_pri;
750	my $grp = aio_group $cb;	1022	my $grp = aio_group $cb;
751		1023
752	aioreq_pri $pri;	1024	aioreq_pri $pri;
753	add $grp aio_scandir $path, 0, sub {	1025	add $grp aio_scandir $path, 0, sub {
754	my ($dirs, $nondirs) = @_;	1026	my ($dirs, $nondirs) = @_;
755		1027
756	my $dirgrp = aio_group sub {	1028	my $dirgrp = aio_group sub {
757	add $grp aio_rmdir $path, sub {	1029	add $grp aio_rmdir $path, sub {
758	$grp->result ($_[0]);	1030	$grp->result ($_[0]);
759	};
760	};	1031	};
761
762	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
763	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
764
765	add $grp $dirgrp;
766	};	1032	};
767		1033
768	$grp	1034	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1035	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1036
		1037	add $grp $dirgrp;
769	}	1038	};
		1039
		1040	$grp
770	}	1041	}
		1042
		1043	=item aio_sync $callback->($status)
		1044
		1045	Asynchronously call sync and call the callback when finished.
771		1046
772	=item aio_fsync $fh, $callback->($status)	1047	=item aio_fsync $fh, $callback->($status)
773		1048
774	Asynchronously call fsync on the given filehandle and call the callback	1049	Asynchronously call fsync on the given filehandle and call the callback
775	with the fsync result code.	1050	with the fsync result code.
…		…
779	Asynchronously call fdatasync on the given filehandle and call the	1054	Asynchronously call fdatasync on the given filehandle and call the
780	callback with the fdatasync result code.	1055	callback with the fdatasync result code.
781		1056
782	If this call isn't available because your OS lacks it or it couldn't be	1057	If this call isn't available because your OS lacks it or it couldn't be
783	detected, it will be emulated by calling C<fsync> instead.	1058	detected, it will be emulated by calling C<fsync> instead.
		1059
		1060	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1061
		1062	Sync the data portion of the file specified by C<$offset> and C<$length>
		1063	to disk (but NOT the metadata), by calling the Linux-specific
		1064	sync_file_range call. If sync_file_range is not available or it returns
		1065	ENOSYS, then fdatasync or fsync is being substituted.
		1066
		1067	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1068	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1069	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1070	manpage for details.
		1071
		1072	=item aio_pathsync $path, $callback->($status)
		1073
		1074	This request tries to open, fsync and close the given path. This is a
		1075	composite request intended to sync directories after directory operations
		1076	(E.g. rename). This might not work on all operating systems or have any
		1077	specific effect, but usually it makes sure that directory changes get
		1078	written to disc. It works for anything that can be opened for read-only,
		1079	not just directories.
		1080
		1081	Future versions of this function might fall back to other methods when
		1082	C<fsync> on the directory fails (such as calling C<sync>).
		1083
		1084	Passes C<0> when everything went ok, and C<-1> on error.
		1085
		1086	=cut
		1087
		1088	sub aio_pathsync($;$) {
		1089	my ($path, $cb) = @_;
		1090
		1091	my $pri = aioreq_pri;
		1092	my $grp = aio_group $cb;
		1093
		1094	aioreq_pri $pri;
		1095	add $grp aio_open $path, O_RDONLY, 0, sub {
		1096	my ($fh) = @_;
		1097	if ($fh) {
		1098	aioreq_pri $pri;
		1099	add $grp aio_fsync $fh, sub {
		1100	$grp->result ($_[0]);
		1101
		1102	aioreq_pri $pri;
		1103	add $grp aio_close $fh;
		1104	};
		1105	} else {
		1106	$grp->result (-1);
		1107	}
		1108	};
		1109
		1110	$grp
		1111	}
		1112
		1113	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1114
		1115	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1116	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1117	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1118	scalar must only be modified in-place while an aio operation is pending on
		1119	it).
		1120
		1121	It calls the C<msync> function of your OS, if available, with the memory
		1122	area starting at C<$offset> in the string and ending C<$length> bytes
		1123	later. If C<$length> is negative, counts from the end, and if C<$length>
		1124	is C<undef>, then it goes till the end of the string. The flags can be
		1125	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1126	C<IO::AIO::MS_SYNC>.
		1127
		1128	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1129
		1130	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1131	scalars.
		1132
		1133	It touches (reads or writes) all memory pages in the specified
		1134	range inside the scalar. All caveats and parameters are the same
		1135	as for C<aio_msync>, above, except for flags, which must be either
		1136	C<0> (which reads all pages and ensures they are instantiated) or
		1137	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1138	writing an octet from it, which dirties the page).
		1139
		1140	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1141
		1142	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1143	scalars.
		1144
		1145	It reads in all the pages of the underlying storage into memory (if any)
		1146	and locks them, so they are not getting swapped/paged out or removed.
		1147
		1148	If C<$length> is undefined, then the scalar will be locked till the end.
		1149
		1150	On systems that do not implement C<mlock>, this function returns C<-1>
		1151	and sets errno to C<ENOSYS>.
		1152
		1153	Note that the corresponding C<munlock> is synchronous and is
		1154	documented under L<MISCELLANEOUS FUNCTIONS>.
		1155
		1156	Example: open a file, mmap and mlock it - both will be undone when
		1157	C<$data> gets destroyed.
		1158
		1159	open my $fh, "<", $path or die "$path: $!";
		1160	my $data;
		1161	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1162	aio_mlock $data; # mlock in background
		1163
		1164	=item aio_mlockall $flags, $callback->($status)
		1165
		1166	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1167	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1168
		1169	On systems that do not implement C<mlockall>, this function returns C<-1>
		1170	and sets errno to C<ENOSYS>.
		1171
		1172	Note that the corresponding C<munlockall> is synchronous and is
		1173	documented under L<MISCELLANEOUS FUNCTIONS>.
		1174
		1175	Example: asynchronously lock all current and future pages into memory.
		1176
		1177	aio_mlockall IO::AIO::MCL_FUTURE;
784		1178
785	=item aio_group $callback->(...)	1179	=item aio_group $callback->(...)
786		1180
787	This is a very special aio request: Instead of doing something, it is a	1181	This is a very special aio request: Instead of doing something, it is a
788	container for other aio requests, which is useful if you want to bundle	1182	container for other aio requests, which is useful if you want to bundle
…		…
838	=item cancel $req	1232	=item cancel $req
839		1233
840	Cancels the request, if possible. Has the effect of skipping execution	1234	Cancels the request, if possible. Has the effect of skipping execution
841	when entering the B<execute> state and skipping calling the callback when	1235	when entering the B<execute> state and skipping calling the callback when
842	entering the the B<result> state, but will leave the request otherwise	1236	entering the the B<result> state, but will leave the request otherwise
843	untouched. That means that requests that currently execute will not be	1237	untouched (with the exception of readdir). That means that requests that
844	stopped and resources held by the request will not be freed prematurely.	1238	currently execute will not be stopped and resources held by the request
		1239	will not be freed prematurely.
845		1240
846	=item cb $req $callback->(...)	1241	=item cb $req $callback->(...)
847		1242
848	Replace (or simply set) the callback registered to the request.	1243	Replace (or simply set) the callback registered to the request.
849		1244
…		…
900	Their lifetime, simplified, looks like this: when they are empty, they	1295	Their lifetime, simplified, looks like this: when they are empty, they
901	will finish very quickly. If they contain only requests that are in the	1296	will finish very quickly. If they contain only requests that are in the
902	C<done> state, they will also finish. Otherwise they will continue to	1297	C<done> state, they will also finish. Otherwise they will continue to
903	exist.	1298	exist.
904		1299
905	That means after creating a group you have some time to add requests. And	1300	That means after creating a group you have some time to add requests
906	in the callbacks of those requests, you can add further requests to the	1301	(precisely before the callback has been invoked, which is only done within
907	group. And only when all those requests have finished will the the group	1302	the C<poll_cb>). And in the callbacks of those requests, you can add
908	itself finish.	1303	further requests to the group. And only when all those requests have
		1304	finished will the the group itself finish.
909		1305
910	=over 4	1306	=over 4
911		1307
912	=item add $grp ...	1308	=item add $grp ...
913		1309
…		…
922	=item $grp->cancel_subs	1318	=item $grp->cancel_subs
923		1319
924	Cancel all subrequests and clears any feeder, but not the group request	1320	Cancel all subrequests and clears any feeder, but not the group request
925	itself. Useful when you queued a lot of events but got a result early.	1321	itself. Useful when you queued a lot of events but got a result early.
926		1322
		1323	The group request will finish normally (you cannot add requests to the
		1324	group).
		1325
927	=item $grp->result (...)	1326	=item $grp->result (...)
928		1327
929	Set the result value(s) that will be passed to the group callback when all	1328	Set the result value(s) that will be passed to the group callback when all
930	subrequests have finished and set thre groups errno to the current value	1329	subrequests have finished and set the groups errno to the current value
931	of errno (just like calling C<errno> without an error number). By default,	1330	of errno (just like calling C<errno> without an error number). By default,
932	no argument will be passed and errno is zero.	1331	no argument will be passed and errno is zero.
933		1332
934	=item $grp->errno ([$errno])	1333	=item $grp->errno ([$errno])
935		1334
…		…
946	=item feed $grp $callback->($grp)	1345	=item feed $grp $callback->($grp)
947		1346
948	Sets a feeder/generator on this group: every group can have an attached	1347	Sets a feeder/generator on this group: every group can have an attached
949	generator that generates requests if idle. The idea behind this is that,	1348	generator that generates requests if idle. The idea behind this is that,
950	although you could just queue as many requests as you want in a group,	1349	although you could just queue as many requests as you want in a group,
951	this might starve other requests for a potentially long time. For	1350	this might starve other requests for a potentially long time. For example,
952	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1351	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
953	requests, delaying any later requests for a long time.	1352	delaying any later requests for a long time.
954		1353
955	To avoid this, and allow incremental generation of requests, you can	1354	To avoid this, and allow incremental generation of requests, you can
956	instead a group and set a feeder on it that generates those requests. The	1355	instead a group and set a feeder on it that generates those requests. The
957	feed callback will be called whenever there are few enough (see C<limit>,	1356	feed callback will be called whenever there are few enough (see C<limit>,
958	below) requests active in the group itself and is expected to queue more	1357	below) requests active in the group itself and is expected to queue more
…		…
962	not impose any limits).	1361	not impose any limits).
963		1362
964	If the feed does not queue more requests when called, it will be	1363	If the feed does not queue more requests when called, it will be
965	automatically removed from the group.	1364	automatically removed from the group.
966		1365
967	If the feed limit is C<0>, it will be set to C<2> automatically.	1366	If the feed limit is C<0> when this method is called, it will be set to
		1367	C<2> automatically.
968		1368
969	Example:	1369	Example:
970		1370
971	# stat all files in @files, but only ever use four aio requests concurrently:	1371	# stat all files in @files, but only ever use four aio requests concurrently:
972		1372
…		…
984	Sets the feeder limit for the group: The feeder will be called whenever	1384	Sets the feeder limit for the group: The feeder will be called whenever
985	the group contains less than this many requests.	1385	the group contains less than this many requests.
986		1386
987	Setting the limit to C<0> will pause the feeding process.	1387	Setting the limit to C<0> will pause the feeding process.
988		1388
		1389	The default value for the limit is C<0>, but note that setting a feeder
		1390	automatically bumps it up to C<2>.
		1391
989	=back	1392	=back
990		1393
991	=head2 SUPPORT FUNCTIONS	1394	=head2 SUPPORT FUNCTIONS
992		1395
993	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1396	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
995	=over 4	1398	=over 4
996		1399
997	=item $fileno = IO::AIO::poll_fileno	1400	=item $fileno = IO::AIO::poll_fileno
998		1401
999	Return the I<request result pipe file descriptor>. This filehandle must be	1402	Return the I<request result pipe file descriptor>. This filehandle must be
1000	polled for reading by some mechanism outside this module (e.g. Event or	1403	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1001	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1404	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1002	to call C<poll_cb> to check the results.	1405	you have to call C<poll_cb> to check the results.
1003		1406
1004	See C<poll_cb> for an example.	1407	See C<poll_cb> for an example.
1005		1408
1006	=item IO::AIO::poll_cb	1409	=item IO::AIO::poll_cb
1007		1410
1008	Process some outstanding events on the result pipe. You have to call this	1411	Process some outstanding events on the result pipe. You have to call this
1009	regularly. Returns the number of events processed. Returns immediately	1412	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1413	returned earlier for whatever reason. Returns immediately when no events
1010	when no events are outstanding. The amount of events processed depends on	1414	are outstanding. The amount of events processed depends on the settings of
1011	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1415	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1012		1416
1013	If not all requests were processed for whatever reason, the filehandle	1417	If not all requests were processed for whatever reason, the filehandle
1014	will still be ready when C<poll_cb> returns.	1418	will still be ready when C<poll_cb> returns, so normally you don't have to
		1419	do anything special to have it called later.
1015		1420
1016	Example: Install an Event watcher that automatically calls	1421	Example: Install an Event watcher that automatically calls
1017	IO::AIO::poll_cb with high priority:	1422	IO::AIO::poll_cb with high priority (more examples can be found in the
		1423	SYNOPSIS section, at the top of this document):
1018		1424
1019	Event->io (fd => IO::AIO::poll_fileno,	1425	Event->io (fd => IO::AIO::poll_fileno,
1020	poll => 'r', async => 1,	1426	poll => 'r', async => 1,
1021	cb => \&IO::AIO::poll_cb);	1427	cb => \&IO::AIO::poll_cb);
		1428
		1429	=item IO::AIO::poll_wait
		1430
		1431	If there are any outstanding requests and none of them in the result
		1432	phase, wait till the result filehandle becomes ready for reading (simply
		1433	does a C<select> on the filehandle. This is useful if you want to
		1434	synchronously wait for some requests to finish).
		1435
		1436	See C<nreqs> for an example.
		1437
		1438	=item IO::AIO::poll
		1439
		1440	Waits until some requests have been handled.
		1441
		1442	Returns the number of requests processed, but is otherwise strictly
		1443	equivalent to:
		1444
		1445	IO::AIO::poll_wait, IO::AIO::poll_cb
		1446
		1447	=item IO::AIO::flush
		1448
		1449	Wait till all outstanding AIO requests have been handled.
		1450
		1451	Strictly equivalent to:
		1452
		1453	IO::AIO::poll_wait, IO::AIO::poll_cb
		1454	while IO::AIO::nreqs;
1022		1455
1023	=item IO::AIO::max_poll_reqs $nreqs	1456	=item IO::AIO::max_poll_reqs $nreqs
1024		1457
1025	=item IO::AIO::max_poll_time $seconds	1458	=item IO::AIO::max_poll_time $seconds
1026		1459
…		…
1051	# use a low priority so other tasks have priority	1484	# use a low priority so other tasks have priority
1052	Event->io (fd => IO::AIO::poll_fileno,	1485	Event->io (fd => IO::AIO::poll_fileno,
1053	poll => 'r', nice => 1,	1486	poll => 'r', nice => 1,
1054	cb => &IO::AIO::poll_cb);	1487	cb => &IO::AIO::poll_cb);
1055		1488
1056	=item IO::AIO::poll_wait
1057
1058	If there are any outstanding requests and none of them in the result
1059	phase, wait till the result filehandle becomes ready for reading (simply
1060	does a C<select> on the filehandle. This is useful if you want to
1061	synchronously wait for some requests to finish).
1062
1063	See C<nreqs> for an example.
1064
1065	=item IO::AIO::poll
1066
1067	Waits until some requests have been handled.
1068
1069	Returns the number of requests processed, but is otherwise strictly
1070	equivalent to:
1071
1072	IO::AIO::poll_wait, IO::AIO::poll_cb
1073
1074	=item IO::AIO::flush
1075
1076	Wait till all outstanding AIO requests have been handled.
1077
1078	Strictly equivalent to:
1079
1080	IO::AIO::poll_wait, IO::AIO::poll_cb
1081	while IO::AIO::nreqs;
1082
1083	=back	1489	=back
1084		1490
1085	=head3 CONTROLLING THE NUMBER OF THREADS	1491	=head3 CONTROLLING THE NUMBER OF THREADS
1086		1492
1087	=over	1493	=over
…		…
1120		1526
1121	Under normal circumstances you don't need to call this function.	1527	Under normal circumstances you don't need to call this function.
1122		1528
1123	=item IO::AIO::max_idle $nthreads	1529	=item IO::AIO::max_idle $nthreads
1124		1530
1125	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1531	Limit the number of threads (default: 4) that are allowed to idle
1126	threads that did not get a request to process within 10 seconds). That	1532	(i.e., threads that did not get a request to process within the idle
1127	means if a thread becomes idle while C<$nthreads> other threads are also	1533	timeout (default: 10 seconds). That means if a thread becomes idle while
1128	idle, it will free its resources and exit.	1534	C<$nthreads> other threads are also idle, it will free its resources and
		1535	exit.
1129		1536
1130	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1537	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1131	to allow for extremely high load situations, but want to free resources	1538	to allow for extremely high load situations, but want to free resources
1132	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1539	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1133		1540
1134	The default is probably ok in most situations, especially if thread	1541	The default is probably ok in most situations, especially if thread
1135	creation is fast. If thread creation is very slow on your system you might	1542	creation is fast. If thread creation is very slow on your system you might
1136	want to use larger values.	1543	want to use larger values.
1137		1544
		1545	=item IO::AIO::idle_timeout $seconds
		1546
		1547	Sets the minimum idle timeout (default 10) after which worker threads are
		1548	allowed to exit. SEe C<IO::AIO::max_idle>.
		1549
1138	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1550	=item IO::AIO::max_outstanding $maxreqs
1139		1551
1140	This is a very bad function to use in interactive programs because it	1552	This is a very bad function to use in interactive programs because it
1141	blocks, and a bad way to reduce concurrency because it is inexact: Better	1553	blocks, and a bad way to reduce concurrency because it is inexact: Better
1142	use an C<aio_group> together with a feed callback.	1554	use an C<aio_group> together with a feed callback.
1143		1555
1144	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1556	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1145	to queue up more than this number of requests, the next call to the	1557	do queue up more than this number of requests, the next call to the
1146	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1558	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1147	function will block until the limit is no longer exceeded.	1559	function will block until the limit is no longer exceeded.
1148		1560
1149	The default value is very large, so there is no practical limit on the	1561	The default value is very large, so there is no practical limit on the
1150	number of outstanding requests.	1562	number of outstanding requests.
1151		1563
1152	You can still queue as many requests as you want. Therefore,	1564	You can still queue as many requests as you want. Therefore,
1153	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1565	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1154	as a stop gap to shield against fatal memory overflow (with large values).	1566	as a stop gap to shield against fatal memory overflow (with large values).
1155		1567
1156	=back	1568	=back
1157		1569
1158	=head3 STATISTICAL INFORMATION	1570	=head3 STATISTICAL INFORMATION
…		…
1179	Returns the number of requests currently in the pending state (executed,	1591	Returns the number of requests currently in the pending state (executed,
1180	but not yet processed by poll_cb).	1592	but not yet processed by poll_cb).
1181		1593
1182	=back	1594	=back
1183		1595
		1596	=head3 MISCELLANEOUS FUNCTIONS
		1597
		1598	IO::AIO implements some functions that might be useful, but are not
		1599	asynchronous.
		1600
		1601	=over 4
		1602
		1603	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1604
		1605	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1606	but is blocking (this makes most sense if you know the input data is
		1607	likely cached already and the output filehandle is set to non-blocking
		1608	operations).
		1609
		1610	Returns the number of bytes copied, or C<-1> on error.
		1611
		1612	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1613
		1614	Simply calls the C<posix_fadvise> function (see its
		1615	manpage for details). The following advice constants are
		1616	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1617	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1618	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1619
		1620	On systems that do not implement C<posix_fadvise>, this function returns
		1621	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1622
		1623	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1624
		1625	Simply calls the C<posix_madvise> function (see its
		1626	manpage for details). The following advice constants are
		1627	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1628	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1629
		1630	On systems that do not implement C<posix_madvise>, this function returns
		1631	ENOSYS, otherwise the return value of C<posix_madvise>.
		1632
		1633	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1634
		1635	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1636	$scalar (see its manpage for details). The following protect
		1637	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1638	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1639
		1640	On systems that do not implement C<mprotect>, this function returns
		1641	ENOSYS, otherwise the return value of C<mprotect>.
		1642
		1643	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1644
		1645	Memory-maps a file (or anonymous memory range) and attaches it to the
		1646	given C<$scalar>, which will act like a string scalar.
		1647
		1648	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1649	change the string length, and most read-only operations such as copying it
		1650	or searching it with regexes and so on.
		1651
		1652	Anything else is unsafe and will, at best, result in memory leaks.
		1653
		1654	The memory map associated with the C<$scalar> is automatically removed
		1655	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1656	C<IO::AIO::munmap> functions are called.
		1657
		1658	This calls the C<mmap>(2) function internally. See your system's manual
		1659	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1660
		1661	The C<$length> must be larger than zero and smaller than the actual
		1662	filesize.
		1663
		1664	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1665	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1666
		1667	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1668	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1669	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1670	(which is set to C<MAP_ANON> if your system only provides this
		1671	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1672	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1673	C<IO::AIO::MAP_NONBLOCK>
		1674
		1675	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1676
		1677	C<$offset> is the offset from the start of the file - it generally must be
		1678	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1679
		1680	Example:
		1681
		1682	use Digest::MD5;
		1683	use IO::AIO;
		1684
		1685	open my $fh, "<verybigfile"
		1686	or die "$!";
		1687
		1688	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1689	or die "verybigfile: $!";
		1690
		1691	my $fast_md5 = md5 $data;
		1692
		1693	=item IO::AIO::munmap $scalar
		1694
		1695	Removes a previous mmap and undefines the C<$scalar>.
		1696
		1697	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1698
		1699	Calls the C<munlock> function, undoing the effects of a previous
		1700	C<aio_mlock> call (see its description for details).
		1701
		1702	=item IO::AIO::munlockall
		1703
		1704	Calls the C<munlockall> function.
		1705
		1706	On systems that do not implement C<munlockall>, this function returns
		1707	ENOSYS, otherwise the return value of C<munlockall>.
		1708
		1709	=back
		1710
1184	=cut	1711	=cut
1185		1712
1186	# support function to convert a fd into a perl filehandle
1187	sub _fd2fh {
1188	return undef if $_[0] < 0;
1189
1190	# try to generate nice filehandles
1191	my $sym = "IO::AIO::fd#$_[0]";
1192	local *$sym;
1193
1194	open *$sym, "+<&=$_[0]" # usually works under any unix
1195	or open *$sym, "<&=$_[0]" # cygwin needs this
1196	or open *$sym, ">&=$_[0]" # or this
1197	or return undef;
1198
1199	*$sym
1200	}
1201
1202	min_parallel 8;	1713	min_parallel 8;
1203		1714
1204	END { flush }	1715	END { flush }
1205		1716
1206	1;	1717	1;
		1718
		1719	=head1 EVENT LOOP INTEGRATION
		1720
		1721	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1722	automatically into many event loops:
		1723
		1724	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1725	use AnyEvent::AIO;
		1726
		1727	You can also integrate IO::AIO manually into many event loops, here are
		1728	some examples of how to do this:
		1729
		1730	# EV integration
		1731	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1732
		1733	# Event integration
		1734	Event->io (fd => IO::AIO::poll_fileno,
		1735	poll => 'r',
		1736	cb => \&IO::AIO::poll_cb);
		1737
		1738	# Glib/Gtk2 integration
		1739	add_watch Glib::IO IO::AIO::poll_fileno,
		1740	in => sub { IO::AIO::poll_cb; 1 };
		1741
		1742	# Tk integration
		1743	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1744	readable => \&IO::AIO::poll_cb);
		1745
		1746	# Danga::Socket integration
		1747	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1748	\&IO::AIO::poll_cb);
1207		1749
1208	=head2 FORK BEHAVIOUR	1750	=head2 FORK BEHAVIOUR
1209		1751
1210	This module should do "the right thing" when the process using it forks:	1752	This module should do "the right thing" when the process using it forks:
1211		1753
…		…
1229	bytes of memory. In addition, stat requests need a stat buffer (possibly	1771	bytes of memory. In addition, stat requests need a stat buffer (possibly
1230	a few hundred bytes), readdir requires a result buffer and so on. Perl	1772	a few hundred bytes), readdir requires a result buffer and so on. Perl
1231	scalars and other data passed into aio requests will also be locked and	1773	scalars and other data passed into aio requests will also be locked and
1232	will consume memory till the request has entered the done state.	1774	will consume memory till the request has entered the done state.
1233		1775
1234	This is now awfully much, so queuing lots of requests is not usually a	1776	This is not awfully much, so queuing lots of requests is not usually a
1235	problem.	1777	problem.
1236		1778
1237	Per-thread usage:	1779	Per-thread usage:
1238		1780
1239	In the execution phase, some aio requests require more memory for	1781	In the execution phase, some aio requests require more memory for
…		…
1244		1786
1245	Known bugs will be fixed in the next release.	1787	Known bugs will be fixed in the next release.
1246		1788
1247	=head1 SEE ALSO	1789	=head1 SEE ALSO
1248		1790
1249	L<Coro::AIO>.	1791	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1792	more natural syntax.
1250		1793
1251	=head1 AUTHOR	1794	=head1 AUTHOR
1252		1795
1253	Marc Lehmann <schmorp@schmorp.de>	1796	Marc Lehmann <schmorp@schmorp.de>
1254	http://home.schmorp.de/	1797	http://home.schmorp.de/

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