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Revision 1.79 by root, Thu Oct 26 14:35:34 2006 UTC vs.
Revision 1.187 by root, Fri Feb 11 00:05:17 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) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
30	# AnyEvent integration
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33
34	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',
37	cb => \&IO::AIO::poll_cb);
38
39	# Glib/Gtk2 integration
40	add_watch Glib::IO IO::AIO::poll_fileno,
41	in => sub { IO::AIO::poll_cb; 1 };
42
43	# Tk integration
44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
45	readable => \&IO::AIO::poll_cb);
46
47	# Danga::Socket integration
48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
49	\&IO::AIO::poll_cb);
50
51	=head1 DESCRIPTION	31	=head1 DESCRIPTION
52		32
53	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
54	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>).
		36
		37	Asynchronous means that operations that can normally block your program
		38	(e.g. reading from disk) will be done asynchronously: the operation
		39	will still block, but you can do something else in the meantime. This
		40	is extremely useful for programs that need to stay interactive even
		41	when doing heavy I/O (GUI programs, high performance network servers
		42	etc.), but can also be used to easily do operations in parallel that are
		43	normally done sequentially, e.g. stat'ing many files, which is much faster
		44	on a RAID volume or over NFS when you do a number of stat operations
		45	concurrently.
		46
		47	While most of this works on all types of file descriptors (for
		48	example sockets), using these functions on file descriptors that
		49	support nonblocking operation (again, sockets, pipes etc.) is
		50	very inefficient. Use an event loop for that (such as the L<EV>
		51	module): IO::AIO will naturally fit into such an event loop itself.
55		52
56	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
57	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
58	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
59	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
60	functions available on many operating systems. However, they are often	57	functions available on many operating systems. However, they are often
61	not well-supported or restricted (Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	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
63	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
64	using threads anyway.	61	using threads anyway.
65		62
66	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,
67	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
68	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
69	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
		67
		68	=head2 EXAMPLE
		69
		70	This is a simple example that uses the EV module and loads
		71	F</etc/passwd> asynchronously:
		72
		73	use Fcntl;
		74	use EV;
		75	use IO::AIO;
		76
		77	# register the IO::AIO callback with EV
		78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		79
		80	# queue the request to open /etc/passwd
		81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
		82	my $fh = shift
		83	or die "error while opening: $!";
		84
		85	# stat'ing filehandles is generally non-blocking
		86	my $size = -s $fh;
		87
		88	# queue a request to read the file
		89	my $contents;
		90	aio_read $fh, 0, $size, $contents, 0, sub {
		91	$_[0] == $size
		92	or die "short read: $!";
		93
		94	close $fh;
		95
		96	# file contents now in $contents
		97	print $contents;
		98
		99	# exit event loop and program
		100	EV::unloop;
		101	};
		102	};
		103
		104	# possibly queue up other requests, or open GUI windows,
		105	# check for sockets etc. etc.
		106
		107	# process events as long as there are some:
		108	EV::loop;
70		109
71	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
72		111
73	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
74	directly visible to Perl.	113	directly visible to Perl.
…		…
116	Request has reached the end of its lifetime and holds no resources anymore	155	Request has reached the end of its lifetime and holds no resources anymore
117	(except possibly for the Perl object, but its connection to the actual	156	(except possibly for the Perl object, but its connection to the actual
118	aio request is severed and calling its methods will either do nothing or	157	aio request is severed and calling its methods will either do nothing or
119	result in a runtime error).	158	result in a runtime error).
120		159
		160	=back
		161
121	=cut	162	=cut
122		163
123	package IO::AIO;	164	package IO::AIO;
124		165
125	no warnings;	166	use Carp ();
126	use strict 'vars';	167
		168	use common::sense;
127		169
128	use base 'Exporter';	170	use base 'Exporter';
129		171
130	BEGIN {	172	BEGIN {
131	our $VERSION = '2.0';	173	our $VERSION = '3.72';
132		174
133	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
134	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
135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	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
		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
136	aio_group aio_nop);	183	aio_statvfs);
		184
137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139	min_parallel max_parallel nreqs);	187	min_parallel max_parallel max_idle
		188	nreqs nready npending nthreads
		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
140		194
141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	195	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142		196
143	require XSLoader;	197	require XSLoader;
144	XSLoader::load ("IO::AIO", $VERSION);	198	XSLoader::load ("IO::AIO", $VERSION);
145	}	199	}
146		200
147	=head1 FUNCTIONS	201	=head1 FUNCTIONS
148		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::max_outstanding $maxreqs
		264	IO::AIO::nreqs
		265	IO::AIO::nready
		266	IO::AIO::npending
		267
		268	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		269	IO::AIO::fadvise $fh, $offset, $len, $advice
		270	IO::AIO::madvise $scalar, $offset, $length, $advice
		271	IO::AIO::mprotect $scalar, $offset, $length, $protect
		272	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		273	IO::AIO::munlockall
		274
149	=head2 AIO FUNCTIONS	275	=head2 AIO REQUEST FUNCTIONS
150		276
151	All the C<aio_*> calls are more or less thin wrappers around the syscall	277	All the C<aio_*> calls are more or less thin wrappers around the syscall
152	with the same name (sans C<aio_>). The arguments are similar or identical,	278	with the same name (sans C<aio_>). The arguments are similar or identical,
153	and they all accept an additional (and optional) C<$callback> argument	279	and they all accept an additional (and optional) C<$callback> argument
154	which must be a code reference. This code reference will get called with	280	which must be a code reference. This code reference will get called with
155	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	281	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
156	perl, which usually delivers "false") as it's sole argument when the given	282	perl, which usually delivers "false") as its sole argument after the given
157	syscall has been executed asynchronously.	283	syscall has been executed asynchronously.
158		284
159	All functions expecting a filehandle keep a copy of the filehandle	285	All functions expecting a filehandle keep a copy of the filehandle
160	internally until the request has finished.	286	internally until the request has finished.
161		287
162	All requests return objects of type L<IO::AIO::REQ> that allow further	288	All functions return request objects of type L<IO::AIO::REQ> that allow
163	manipulation of those requests while they are in-flight.	289	further manipulation of those requests while they are in-flight.
164		290
165	The pathnames you pass to these routines I<must> be absolute and	291	The pathnames you pass to these routines I<must> be absolute and
166	encoded in byte form. The reason for the former is that at the time the	292	encoded as octets. The reason for the former is that at the time the
167	request is being executed, the current working directory could have	293	request is being executed, the current working directory could have
168	changed. Alternatively, you can make sure that you never change the	294	changed. Alternatively, you can make sure that you never change the
169	current working directory.	295	current working directory anywhere in the program and then use relative
		296	paths.
170		297
171	To encode pathnames to byte form, either make sure you either: a)	298	To encode pathnames as octets, either make sure you either: a) always pass
172	always pass in filenames you got from outside (command line, readdir	299	in filenames you got from outside (command line, readdir etc.) without
173	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	300	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174	your pathnames to the locale (or other) encoding in effect in the user	301	your pathnames to the locale (or other) encoding in effect in the user
175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	302	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176	use something else.	303	use something else to ensure your scalar has the correct contents.
		304
		305	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		306	handles correctly whether it is set or not.
177		307
178	=over 4	308	=over 4
179		309
180	=item aioreq_pri $pri	310	=item $prev_pri = aioreq_pri [$pri]
181		311
182	Sets the priority for the next aio request. The default priority	312	Returns the priority value that would be used for the next request and, if
		313	C<$pri> is given, sets the priority for the next aio request.
		314
183	is C<0>, the minimum and maximum priorities are C<-4> and C<4>,	315	The default priority is C<0>, the minimum and maximum priorities are C<-4>
184	respectively. Requests with higher priority will be serviced first.	316	and C<4>, respectively. Requests with higher priority will be serviced
		317	first.
185		318
186	The priority will be reset to C<0> after each call to one of the C<aio_>	319	The priority will be reset to C<0> after each call to one of the C<aio_*>
187	functions.	320	functions.
188		321
189	Example: open a file with low priority, then read something from it with	322	Example: open a file with low priority, then read something from it with
190	higher priority so the read request is serviced before other low priority	323	higher priority so the read request is serviced before other low priority
191	open requests (potentially spamming the cache):	324	open requests (potentially spamming the cache):
…		…
198	aio_read $_[0], ..., sub {	331	aio_read $_[0], ..., sub {
199	...	332	...
200	};	333	};
201	};	334	};
202		335
		336
203	=item aioreq_nice $pri_adjust	337	=item aioreq_nice $pri_adjust
204		338
205	Similar to C<aioreq_pri>, but subtracts the given value from the current	339	Similar to C<aioreq_pri>, but subtracts the given value from the current
206	priority, so effects are cumulative.	340	priority, so the effect is cumulative.
		341
207		342
208	=item aio_open $pathname, $flags, $mode, $callback->($fh)	343	=item aio_open $pathname, $flags, $mode, $callback->($fh)
209		344
210	Asynchronously open or create a file and call the callback with a newly	345	Asynchronously open or create a file and call the callback with a newly
211	created filehandle for the file.	346	created filehandle for the file.
…		…
217	list. They are the same as used by C<sysopen>.	352	list. They are the same as used by C<sysopen>.
218		353
219	Likewise, C<$mode> specifies the mode of the newly created file, if it	354	Likewise, C<$mode> specifies the mode of the newly created file, if it
220	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	355	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
221	except that it is mandatory (i.e. use C<0> if you don't create new files,	356	except that it is mandatory (i.e. use C<0> if you don't create new files,
222	and C<0666> or C<0777> if you do).	357	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		358	by the umask in effect then the request is being executed, so better never
		359	change the umask.
223		360
224	Example:	361	Example:
225		362
226	aio_open "/etc/passwd", O_RDONLY, 0, sub {	363	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
227	if ($_[0]) {	364	if ($_[0]) {
228	print "open successful, fh is $_[0]\n";	365	print "open successful, fh is $_[0]\n";
229	...	366	...
230	} else {	367	} else {
231	die "open failed: $!\n";	368	die "open failed: $!\n";
232	}	369	}
233	};	370	};
234		371
		372
235	=item aio_close $fh, $callback->($status)	373	=item aio_close $fh, $callback->($status)
236		374
237	Asynchronously close a file and call the callback with the result	375	Asynchronously close a file and call the callback with the result
238	code. I<WARNING:> although accepted, you should not pass in a perl	376	code.
239	filehandle here, as perl will likely close the file descriptor another
240	time when the filehandle is destroyed. Normally, you can safely call perls
241	C<close> or just let filehandles go out of scope.
242		377
243	This is supposed to be a bug in the API, so that might change. It's	378	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
244	therefore best to avoid this function.	379	closing the file descriptor associated with the filehandle itself.
		380
		381	Therefore, C<aio_close> will not close the filehandle - instead it will
		382	use dup2 to overwrite the file descriptor with the write-end of a pipe
		383	(the pipe fd will be created on demand and will be cached).
		384
		385	Or in other words: the file descriptor will be closed, but it will not be
		386	free for reuse until the perl filehandle is closed.
		387
		388	=cut
245		389
246	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	390	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
247		391
248	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	392	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
249		393
250	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	394	Reads or writes C<$length> bytes from or to the specified C<$fh> and
251	into the scalar given by C<data> and offset C<dataoffset> and calls the	395	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
252	callback without the actual number of bytes read (or -1 on error, just	396	and calls the callback without the actual number of bytes read (or -1 on
253	like the syscall).	397	error, just like the syscall).
		398
		399	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		400	offset plus the actual number of bytes read.
		401
		402	If C<$offset> is undefined, then the current file descriptor offset will
		403	be used (and updated), otherwise the file descriptor offset will not be
		404	changed by these calls.
		405
		406	If C<$length> is undefined in C<aio_write>, use the remaining length of
		407	C<$data>.
		408
		409	If C<$dataoffset> is less than zero, it will be counted from the end of
		410	C<$data>.
254		411
255	The C<$data> scalar I<MUST NOT> be modified in any way while the request	412	The C<$data> scalar I<MUST NOT> be modified in any way while the request
256	is outstanding. Modifying it can result in segfaults or WW3 (if the	413	is outstanding. Modifying it can result in segfaults or World War III (if
257	necessary/optional hardware is installed).	414	the necessary/optional hardware is installed).
258		415
259	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	416	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
260	offset C<0> within the scalar:	417	offset C<0> within the scalar:
261		418
262	aio_read $fh, 7, 15, $buffer, 0, sub {	419	aio_read $fh, 7, 15, $buffer, 0, sub {
263	$_[0] > 0 or die "read error: $!";	420	$_[0] > 0 or die "read error: $!";
264	print "read $_[0] bytes: <$buffer>\n";	421	print "read $_[0] bytes: <$buffer>\n";
265	};	422	};
266		423
267	=item aio_move $srcpath, $dstpath, $callback->($status)
268
269	Try to move the I<file> (directories not supported as either source or
270	destination) from C<$srcpath> to C<$dstpath> and call the callback with
271	the C<0> (error) or C<-1> ok.
272
273	This is a composite request that tries to rename(2) the file first. If
274	rename files with C<EXDEV>, it creates the destination file with mode 0200
275	and copies the contents of the source file into it using C<aio_sendfile>,
276	followed by restoring atime, mtime, access mode and uid/gid, in that
277	order, and unlinking the C<$srcpath>.
278
279	If an error occurs, the partial destination file will be unlinked, if
280	possible, except when setting atime, mtime, access mode and uid/gid, where
281	errors are being ignored.
282
283	=cut
284
285	sub aio_move($$$) {
286	my ($src, $dst, $cb) = @_;
287
288	my $grp = aio_group $cb;
289
290	add $grp aio_rename $src, $dst, sub {
291	if ($_[0] && $! == EXDEV) {
292	add $grp aio_open $src, O_RDONLY, 0, sub {
293	if (my $src_fh = $_[0]) {
294	my @stat = stat $src_fh;
295
296	add $grp aio_open $dst, O_WRONLY, 0200, sub {
297	if (my $dst_fh = $_[0]) {
298	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
299	close $src_fh;
300
301	if ($_[0] == $stat[7]) {
302	utime $stat[8], $stat[9], $dst;
303	chmod $stat[2] & 07777, $dst_fh;
304	chown $stat[4], $stat[5], $dst_fh;
305	close $dst_fh;
306
307	add $grp aio_unlink $src, sub {
308	$grp->result ($_[0]);
309	};
310	} else {
311	my $errno = $!;
312	add $grp aio_unlink $dst, sub {
313	$! = $errno;
314	$grp->result (-1);
315	};
316	}
317	};
318	} else {
319	$grp->result (-1);
320	}
321	},
322
323	} else {
324	$grp->result (-1);
325	}
326	};
327	} else {
328	$grp->result ($_[0]);
329	}
330	};
331
332	$grp
333	}
334		424
335	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	425	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
336		426
337	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	427	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
338	reading at byte offset C<$in_offset>, and starts writing at the current	428	reading at byte offset C<$in_offset>, and starts writing at the current
339	file offset of C<$out_fh>. Because of that, it is not safe to issue more	429	file offset of C<$out_fh>. Because of that, it is not safe to issue more
340	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	430	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
341	other.	431	other.
342		432
		433	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		434	are written, and there is no way to find out how many bytes have been read
		435	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
		436	bytes written to C<$out_fh>. Only if the result value equals C<$length>
		437	one can assume that C<$length> bytes have been read.
		438
		439	Unlike with other C<aio_> functions, it makes a lot of sense to use
		440	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		441	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		442	the socket I/O will be non-blocking. Note, however, that you can run into
		443	a trap where C<aio_sendfile> reads some data with readahead, then fails
		444	to write all data, and when the socket is ready the next time, the data
		445	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		446	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		447	much better.
		448
343	This call tries to make use of a native C<sendfile> syscall to provide	449	This call tries to make use of a native C<sendfile> syscall to provide
344	zero-copy operation. For this to work, C<$out_fh> should refer to a	450	zero-copy operation. For this to work, C<$out_fh> should refer to a
345	socket, and C<$in_fh> should refer to mmap'able file.	451	socket, and C<$in_fh> should refer to an mmap'able file.
346		452
347	If the native sendfile call fails or is not implemented, it will be	453	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		454	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
348	emulated, so you can call C<aio_sendfile> on any type of filehandle	455	it will be emulated, so you can call C<aio_sendfile> on any type of
349	regardless of the limitations of the operating system.	456	filehandle regardless of the limitations of the operating system.
350		457
351	Please note, however, that C<aio_sendfile> can read more bytes from
352	C<$in_fh> than are written, and there is no way to find out how many
353	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
354	provides the number of bytes written to C<$out_fh>. Only if the result
355	value equals C<$length> one can assume that C<$length> bytes have been
356	read.
357		458
358	=item aio_readahead $fh,$offset,$length, $callback->($retval)	459	=item aio_readahead $fh,$offset,$length, $callback->($retval)
359		460
360	C<aio_readahead> populates the page cache with data from a file so that	461	C<aio_readahead> populates the page cache with data from a file so that
361	subsequent reads from that file will not block on disk I/O. The C<$offset>	462	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
367	file. The current file offset of the file is left unchanged.	468	file. The current file offset of the file is left unchanged.
368		469
369	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	470	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
370	emulated by simply reading the data, which would have a similar effect.	471	emulated by simply reading the data, which would have a similar effect.
371		472
		473
372	=item aio_stat $fh_or_path, $callback->($status)	474	=item aio_stat $fh_or_path, $callback->($status)
373		475
374	=item aio_lstat $fh, $callback->($status)	476	=item aio_lstat $fh, $callback->($status)
375		477
376	Works like perl's C<stat> or C<lstat> in void context. The callback will	478	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
381	for an explanation.	483	for an explanation.
382		484
383	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	485	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
384	error when stat'ing a large file, the results will be silently truncated	486	error when stat'ing a large file, the results will be silently truncated
385	unless perl itself is compiled with large file support.	487	unless perl itself is compiled with large file support.
		488
		489	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		490	following constants and functions (if not implemented, the constants will
		491	be C<0> and the functions will either C<croak> or fall back on traditional
		492	behaviour).
		493
		494	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		495	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		496	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
386		497
387	Example: Print the length of F</etc/passwd>:	498	Example: Print the length of F</etc/passwd>:
388		499
389	aio_stat "/etc/passwd", sub {	500	aio_stat "/etc/passwd", sub {
390	$_[0] and die "stat failed: $!";	501	$_[0] and die "stat failed: $!";
391	print "size is ", -s _, "\n";	502	print "size is ", -s _, "\n";
392	};	503	};
393		504
		505
		506	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		507
		508	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		509	whether a file handle or path was passed.
		510
		511	On success, the callback is passed a hash reference with the following
		512	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		513	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		514	is passed.
		515
		516	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		517	C<ST_NOSUID>.
		518
		519	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		520	their correct value when available, or to C<0> on systems that do
		521	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		522	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		523	C<ST_NODIRATIME> and C<ST_RELATIME>.
		524
		525	Example: stat C</wd> and dump out the data if successful.
		526
		527	aio_statvfs "/wd", sub {
		528	my $f = $_[0]
		529	or die "statvfs: $!";
		530
		531	use Data::Dumper;
		532	say Dumper $f;
		533	};
		534
		535	# result:
		536	{
		537	bsize => 1024,
		538	bfree => 4333064312,
		539	blocks => 10253828096,
		540	files => 2050765568,
		541	flag => 4096,
		542	favail => 2042092649,
		543	bavail => 4333064312,
		544	ffree => 2042092649,
		545	namemax => 255,
		546	frsize => 1024,
		547	fsid => 1810
		548	}
		549
		550
		551	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		552
		553	Works like perl's C<utime> function (including the special case of $atime
		554	and $mtime being undef). Fractional times are supported if the underlying
		555	syscalls support them.
		556
		557	When called with a pathname, uses utimes(2) if available, otherwise
		558	utime(2). If called on a file descriptor, uses futimes(2) if available,
		559	otherwise returns ENOSYS, so this is not portable.
		560
		561	Examples:
		562
		563	# set atime and mtime to current time (basically touch(1)):
		564	aio_utime "path", undef, undef;
		565	# set atime to current time and mtime to beginning of the epoch:
		566	aio_utime "path", time, undef; # undef==0
		567
		568
		569	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		570
		571	Works like perl's C<chown> function, except that C<undef> for either $uid
		572	or $gid is being interpreted as "do not change" (but -1 can also be used).
		573
		574	Examples:
		575
		576	# same as "chown root path" in the shell:
		577	aio_chown "path", 0, -1;
		578	# same as above:
		579	aio_chown "path", 0, undef;
		580
		581
		582	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		583
		584	Works like truncate(2) or ftruncate(2).
		585
		586
		587	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		588
		589	Works like perl's C<chmod> function.
		590
		591
394	=item aio_unlink $pathname, $callback->($status)	592	=item aio_unlink $pathname, $callback->($status)
395		593
396	Asynchronously unlink (delete) a file and call the callback with the	594	Asynchronously unlink (delete) a file and call the callback with the
397	result code.	595	result code.
398		596
		597
		598	=item aio_mknod $path, $mode, $dev, $callback->($status)
		599
		600	[EXPERIMENTAL]
		601
		602	Asynchronously create a device node (or fifo). See mknod(2).
		603
		604	The only (POSIX-) portable way of calling this function is:
		605
		606	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		607
		608	See C<aio_stat> for info about some potentially helpful extra constants
		609	and functions.
		610
399	=item aio_link $srcpath, $dstpath, $callback->($status)	611	=item aio_link $srcpath, $dstpath, $callback->($status)
400		612
401	Asynchronously create a new link to the existing object at C<$srcpath> at	613	Asynchronously create a new link to the existing object at C<$srcpath> at
402	the path C<$dstpath> and call the callback with the result code.	614	the path C<$dstpath> and call the callback with the result code.
403		615
		616
404	=item aio_symlink $srcpath, $dstpath, $callback->($status)	617	=item aio_symlink $srcpath, $dstpath, $callback->($status)
405		618
406	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	619	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
407	the path C<$dstpath> and call the callback with the result code.	620	the path C<$dstpath> and call the callback with the result code.
408		621
		622
		623	=item aio_readlink $path, $callback->($link)
		624
		625	Asynchronously read the symlink specified by C<$path> and pass it to
		626	the callback. If an error occurs, nothing or undef gets passed to the
		627	callback.
		628
		629
409	=item aio_rename $srcpath, $dstpath, $callback->($status)	630	=item aio_rename $srcpath, $dstpath, $callback->($status)
410		631
411	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	632	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
412	rename(2) and call the callback with the result code.	633	rename(2) and call the callback with the result code.
413		634
		635
		636	=item aio_mkdir $pathname, $mode, $callback->($status)
		637
		638	Asynchronously mkdir (create) a directory and call the callback with
		639	the result code. C<$mode> will be modified by the umask at the time the
		640	request is executed, so do not change your umask.
		641
		642
414	=item aio_rmdir $pathname, $callback->($status)	643	=item aio_rmdir $pathname, $callback->($status)
415		644
416	Asynchronously rmdir (delete) a directory and call the callback with the	645	Asynchronously rmdir (delete) a directory and call the callback with the
417	result code.	646	result code.
		647
418		648
419	=item aio_readdir $pathname, $callback->($entries)	649	=item aio_readdir $pathname, $callback->($entries)
420		650
421	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	651	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
422	directory (i.e. opendir + readdir + closedir). The entries will not be	652	directory (i.e. opendir + readdir + closedir). The entries will not be
423	sorted, and will B<NOT> include the C<.> and C<..> entries.	653	sorted, and will B<NOT> include the C<.> and C<..> entries.
424		654
425	The callback a single argument which is either C<undef> or an array-ref	655	The callback is passed a single argument which is either C<undef> or an
426	with the filenames.	656	array-ref with the filenames.
		657
		658
		659	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		660
		661	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		662	behaviour and output format. In case of an error, C<$entries> will be
		663	C<undef>.
		664
		665	The flags are a combination of the following constants, ORed together (the
		666	flags will also be passed to the callback, possibly modified):
		667
		668	=over 4
		669
		670	=item IO::AIO::READDIR_DENTS
		671
		672	When this flag is off, then the callback gets an arrayref with of names
		673	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		674	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		675	entry in more detail.
		676
		677	C<$name> is the name of the entry.
		678
		679	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		680
		681	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		682	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		683	C<IO::AIO::DT_WHT>.
		684
		685	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		686	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		687	scalars are read-only: you can not modify them.
		688
		689	C<$inode> is the inode number (which might not be exact on systems with 64
		690	bit inode numbers and 32 bit perls). This field has unspecified content on
		691	systems that do not deliver the inode information.
		692
		693	=item IO::AIO::READDIR_DIRS_FIRST
		694
		695	When this flag is set, then the names will be returned in an order where
		696	likely directories come first. This is useful when you need to quickly
		697	find directories, or you want to find all directories while avoiding to
		698	stat() each entry.
		699
		700	If the system returns type information in readdir, then this is used
		701	to find directories directly. Otherwise, likely directories are files
		702	beginning with ".", or otherwise files with no dots, of which files with
		703	short names are tried first.
		704
		705	=item IO::AIO::READDIR_STAT_ORDER
		706
		707	When this flag is set, then the names will be returned in an order
		708	suitable for stat()'ing each one. That is, when you plan to stat()
		709	all files in the given directory, then the returned order will likely
		710	be fastest.
		711
		712	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		713	the likely dirs come first, resulting in a less optimal stat order.
		714
		715	=item IO::AIO::READDIR_FOUND_UNKNOWN
		716
		717	This flag should not be set when calling C<aio_readdirx>. Instead, it
		718	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		719	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		720	C<$type>'s are known, which can be used to speed up some algorithms.
		721
		722	=back
		723
		724
		725	=item aio_load $path, $data, $callback->($status)
		726
		727	This is a composite request that tries to fully load the given file into
		728	memory. Status is the same as with aio_read.
		729
		730	=cut
		731
		732	sub aio_load($$;$) {
		733	my ($path, undef, $cb) = @_;
		734	my $data = \$_[1];
		735
		736	my $pri = aioreq_pri;
		737	my $grp = aio_group $cb;
		738
		739	aioreq_pri $pri;
		740	add $grp aio_open $path, O_RDONLY, 0, sub {
		741	my $fh = shift
		742	or return $grp->result (-1);
		743
		744	aioreq_pri $pri;
		745	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		746	$grp->result ($_[0]);
		747	};
		748	};
		749
		750	$grp
		751	}
		752
		753	=item aio_copy $srcpath, $dstpath, $callback->($status)
		754
		755	Try to copy the I<file> (directories not supported as either source or
		756	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		757	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		758
		759	This is a composite request that creates the destination file with
		760	mode 0200 and copies the contents of the source file into it using
		761	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		762	uid/gid, in that order.
		763
		764	If an error occurs, the partial destination file will be unlinked, if
		765	possible, except when setting atime, mtime, access mode and uid/gid, where
		766	errors are being ignored.
		767
		768	=cut
		769
		770	sub aio_copy($$;$) {
		771	my ($src, $dst, $cb) = @_;
		772
		773	my $pri = aioreq_pri;
		774	my $grp = aio_group $cb;
		775
		776	aioreq_pri $pri;
		777	add $grp aio_open $src, O_RDONLY, 0, sub {
		778	if (my $src_fh = $_[0]) {
		779	my @stat = stat $src_fh; # hmm, might block over nfs?
		780
		781	aioreq_pri $pri;
		782	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
		783	if (my $dst_fh = $_[0]) {
		784	aioreq_pri $pri;
		785	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		786	if ($_[0] == $stat[7]) {
		787	$grp->result (0);
		788	close $src_fh;
		789
		790	my $ch = sub {
		791	aioreq_pri $pri;
		792	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		793	aioreq_pri $pri;
		794	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		795	aioreq_pri $pri;
		796	add $grp aio_close $dst_fh;
		797	}
		798	};
		799	};
		800
		801	aioreq_pri $pri;
		802	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		803	if ($_[0] < 0 && $! == ENOSYS) {
		804	aioreq_pri $pri;
		805	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		806	} else {
		807	$ch->();
		808	}
		809	};
		810	} else {
		811	$grp->result (-1);
		812	close $src_fh;
		813	close $dst_fh;
		814
		815	aioreq $pri;
		816	add $grp aio_unlink $dst;
		817	}
		818	};
		819	} else {
		820	$grp->result (-1);
		821	}
		822	},
		823
		824	} else {
		825	$grp->result (-1);
		826	}
		827	};
		828
		829	$grp
		830	}
		831
		832	=item aio_move $srcpath, $dstpath, $callback->($status)
		833
		834	Try to move the I<file> (directories not supported as either source or
		835	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		836	a status of C<0> (ok) or C<-1> (error, see C<$!>).
		837
		838	This is a composite request that tries to rename(2) the file first; if
		839	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
		840	that is successful, unlinks the C<$srcpath>.
		841
		842	=cut
		843
		844	sub aio_move($$;$) {
		845	my ($src, $dst, $cb) = @_;
		846
		847	my $pri = aioreq_pri;
		848	my $grp = aio_group $cb;
		849
		850	aioreq_pri $pri;
		851	add $grp aio_rename $src, $dst, sub {
		852	if ($_[0] && $! == EXDEV) {
		853	aioreq_pri $pri;
		854	add $grp aio_copy $src, $dst, sub {
		855	$grp->result ($_[0]);
		856
		857	if (!$_[0]) {
		858	aioreq_pri $pri;
		859	add $grp aio_unlink $src;
		860	}
		861	};
		862	} else {
		863	$grp->result ($_[0]);
		864	}
		865	};
		866
		867	$grp
		868	}
427		869
428	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	870	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
429		871
430	Scans a directory (similar to C<aio_readdir>) but additionally tries to	872	Scans a directory (similar to C<aio_readdir>) but additionally tries to
431	efficiently separate the entries of directory C<$path> into two sets of	873	efficiently separate the entries of directory C<$path> into two sets of
…		…
433	recurse into (everything else, including symlinks to directories).	875	recurse into (everything else, including symlinks to directories).
434		876
435	C<aio_scandir> is a composite request that creates of many sub requests_	877	C<aio_scandir> is a composite request that creates of many sub requests_
436	C<$maxreq> specifies the maximum number of outstanding aio requests that	878	C<$maxreq> specifies the maximum number of outstanding aio requests that
437	this function generates. If it is C<< <= 0 >>, then a suitable default	879	this function generates. If it is C<< <= 0 >>, then a suitable default
438	will be chosen (currently 6).	880	will be chosen (currently 4).
439		881
440	On error, the callback is called without arguments, otherwise it receives	882	On error, the callback is called without arguments, otherwise it receives
441	two array-refs with path-relative entry names.	883	two array-refs with path-relative entry names.
442		884
443	Example:	885	Example:
…		…
450		892
451	Implementation notes.	893	Implementation notes.
452		894
453	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	895	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
454		896
		897	If readdir returns file type information, then this is used directly to
		898	find directories.
		899
455	After reading the directory, the modification time, size etc. of the	900	Otherwise, after reading the directory, the modification time, size etc.
456	directory before and after the readdir is checked, and if they match (and	901	of the directory before and after the readdir is checked, and if they
457	isn't the current time), the link count will be used to decide how many	902	match (and isn't the current time), the link count will be used to decide
458	entries are directories (if >= 2). Otherwise, no knowledge of the number	903	how many entries are directories (if >= 2). Otherwise, no knowledge of the
459	of subdirectories will be assumed.	904	number of subdirectories will be assumed.
460		905
461	Then entries will be sorted into likely directories (everything without	906	Then entries will be sorted into likely directories a non-initial dot
462	a non-initial dot currently) and likely non-directories (everything	907	currently) and likely non-directories (see C<aio_readdirx>). Then every
463	else). Then every entry plus an appended C</.> will be C<stat>'ed,	908	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
464	likely directories first. If that succeeds, it assumes that the entry	909	in order of their inode numbers. If that succeeds, it assumes that the
465	is a directory or a symlink to directory (which will be checked	910	entry is a directory or a symlink to directory (which will be checked
466	seperately). This is often faster than stat'ing the entry itself because	911	seperately). This is often faster than stat'ing the entry itself because
467	filesystems might detect the type of the entry without reading the inode	912	filesystems might detect the type of the entry without reading the inode
468	data (e.g. ext2fs filetype feature).	913	data (e.g. ext2fs filetype feature), even on systems that cannot return
		914	the filetype information on readdir.
469		915
470	If the known number of directories (link count - 2) has been reached, the	916	If the known number of directories (link count - 2) has been reached, the
471	rest of the entries is assumed to be non-directories.	917	rest of the entries is assumed to be non-directories.
472		918
473	This only works with certainty on POSIX (= UNIX) filesystems, which	919	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
477	as those tend to return 0 or 1 as link counts, which disables the	923	as those tend to return 0 or 1 as link counts, which disables the
478	directory counting heuristic.	924	directory counting heuristic.
479		925
480	=cut	926	=cut
481		927
482	sub aio_scandir($$$) {	928	sub aio_scandir($$;$) {
483	my ($path, $maxreq, $cb) = @_;	929	my ($path, $maxreq, $cb) = @_;
484		930
		931	my $pri = aioreq_pri;
		932
485	my $grp = aio_group $cb;	933	my $grp = aio_group $cb;
486		934
487	$maxreq = 6 if $maxreq <= 0;	935	$maxreq = 4 if $maxreq <= 0;
488		936
489	# stat once	937	# stat once
		938	aioreq_pri $pri;
490	add $grp aio_stat $path, sub {	939	add $grp aio_stat $path, sub {
491	return $grp->result () if $_[0];	940	return $grp->result () if $_[0];
492	my $now = time;	941	my $now = time;
493	my $hash1 = join ":", (stat _)[0,1,3,7,9];	942	my $hash1 = join ":", (stat _)[0,1,3,7,9];
494		943
495	# read the directory entries	944	# read the directory entries
		945	aioreq_pri $pri;
496	add $grp aio_readdir $path, sub {	946	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
497	my $entries = shift	947	my $entries = shift
498	or return $grp->result ();	948	or return $grp->result ();
499		949
500	# stat the dir another time	950	# stat the dir another time
		951	aioreq_pri $pri;
501	add $grp aio_stat $path, sub {	952	add $grp aio_stat $path, sub {
502	my $hash2 = join ":", (stat _)[0,1,3,7,9];	953	my $hash2 = join ":", (stat _)[0,1,3,7,9];
503		954
504	my $ndirs;	955	my $ndirs;
505		956
506	# take the slow route if anything looks fishy	957	# take the slow route if anything looks fishy
507	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	958	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
508	$ndirs = -1;	959	$ndirs = -1;
509	} else {	960	} else {
510	# if nlink == 2, we are finished	961	# if nlink == 2, we are finished
511	# on non-posix-fs's, we rely on nlink < 2	962	# for non-posix-fs's, we rely on nlink < 2
512	$ndirs = (stat _)[3] - 2	963	$ndirs = (stat _)[3] - 2
513	or return $grp->result ([], $entries);	964	or return $grp->result ([], $entries);
514	}	965	}
515		966
516	# sort into likely dirs and likely nondirs
517	# dirs == files without ".", short entries first
518	$entries = [map $_->[0],
519	sort { $b->[1] cmp $a->[1] }
520	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
521	@$entries];
522
523	my (@dirs, @nondirs);	967	my (@dirs, @nondirs);
524		968
525	my $statgrp = add $grp aio_group sub {	969	my $statgrp = add $grp aio_group sub {
526	$grp->result (\@dirs, \@nondirs);	970	$grp->result (\@dirs, \@nondirs);
527	};	971	};
528		972
529	limit $statgrp $maxreq;	973	limit $statgrp $maxreq;
530	feed $statgrp sub {	974	feed $statgrp sub {
531	return unless @$entries;	975	return unless @$entries;
532	my $entry = pop @$entries;	976	my $entry = shift @$entries;
533		977
		978	aioreq_pri $pri;
534	add $statgrp aio_stat "$path/$entry/.", sub {	979	add $statgrp aio_stat "$path/$entry/.", sub {
535	if ($_[0] < 0) {	980	if ($_[0] < 0) {
536	push @nondirs, $entry;	981	push @nondirs, $entry;
537	} else {	982	} else {
538	# need to check for real directory	983	# need to check for real directory
		984	aioreq_pri $pri;
539	add $statgrp aio_lstat "$path/$entry", sub {	985	add $statgrp aio_lstat "$path/$entry", sub {
540	if (-d _) {	986	if (-d _) {
541	push @dirs, $entry;	987	push @dirs, $entry;
542		988
543	unless (--$ndirs) {	989	unless (--$ndirs) {
…		…
556	};	1002	};
557		1003
558	$grp	1004	$grp
559	}	1005	}
560		1006
		1007	=item aio_rmtree $path, $callback->($status)
		1008
		1009	Delete a directory tree starting (and including) C<$path>, return the
		1010	status of the final C<rmdir> only. This is a composite request that
		1011	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		1012	everything else.
		1013
		1014	=cut
		1015
		1016	sub aio_rmtree;
		1017	sub aio_rmtree($;$) {
		1018	my ($path, $cb) = @_;
		1019
		1020	my $pri = aioreq_pri;
		1021	my $grp = aio_group $cb;
		1022
		1023	aioreq_pri $pri;
		1024	add $grp aio_scandir $path, 0, sub {
		1025	my ($dirs, $nondirs) = @_;
		1026
		1027	my $dirgrp = aio_group sub {
		1028	add $grp aio_rmdir $path, sub {
		1029	$grp->result ($_[0]);
		1030	};
		1031	};
		1032
		1033	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1034	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1035
		1036	add $grp $dirgrp;
		1037	};
		1038
		1039	$grp
		1040	}
		1041
		1042	=item aio_sync $callback->($status)
		1043
		1044	Asynchronously call sync and call the callback when finished.
		1045
561	=item aio_fsync $fh, $callback->($status)	1046	=item aio_fsync $fh, $callback->($status)
562		1047
563	Asynchronously call fsync on the given filehandle and call the callback	1048	Asynchronously call fsync on the given filehandle and call the callback
564	with the fsync result code.	1049	with the fsync result code.
565		1050
…		…
568	Asynchronously call fdatasync on the given filehandle and call the	1053	Asynchronously call fdatasync on the given filehandle and call the
569	callback with the fdatasync result code.	1054	callback with the fdatasync result code.
570		1055
571	If this call isn't available because your OS lacks it or it couldn't be	1056	If this call isn't available because your OS lacks it or it couldn't be
572	detected, it will be emulated by calling C<fsync> instead.	1057	detected, it will be emulated by calling C<fsync> instead.
		1058
		1059	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1060
		1061	Sync the data portion of the file specified by C<$offset> and C<$length>
		1062	to disk (but NOT the metadata), by calling the Linux-specific
		1063	sync_file_range call. If sync_file_range is not available or it returns
		1064	ENOSYS, then fdatasync or fsync is being substituted.
		1065
		1066	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1067	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1068	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1069	manpage for details.
		1070
		1071	=item aio_pathsync $path, $callback->($status)
		1072
		1073	This request tries to open, fsync and close the given path. This is a
		1074	composite request intended to sync directories after directory operations
		1075	(E.g. rename). This might not work on all operating systems or have any
		1076	specific effect, but usually it makes sure that directory changes get
		1077	written to disc. It works for anything that can be opened for read-only,
		1078	not just directories.
		1079
		1080	Future versions of this function might fall back to other methods when
		1081	C<fsync> on the directory fails (such as calling C<sync>).
		1082
		1083	Passes C<0> when everything went ok, and C<-1> on error.
		1084
		1085	=cut
		1086
		1087	sub aio_pathsync($;$) {
		1088	my ($path, $cb) = @_;
		1089
		1090	my $pri = aioreq_pri;
		1091	my $grp = aio_group $cb;
		1092
		1093	aioreq_pri $pri;
		1094	add $grp aio_open $path, O_RDONLY, 0, sub {
		1095	my ($fh) = @_;
		1096	if ($fh) {
		1097	aioreq_pri $pri;
		1098	add $grp aio_fsync $fh, sub {
		1099	$grp->result ($_[0]);
		1100
		1101	aioreq_pri $pri;
		1102	add $grp aio_close $fh;
		1103	};
		1104	} else {
		1105	$grp->result (-1);
		1106	}
		1107	};
		1108
		1109	$grp
		1110	}
		1111
		1112	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1113
		1114	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1115	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1116	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1117	scalar must only be modified in-place while an aio operation is pending on
		1118	it).
		1119
		1120	It calls the C<msync> function of your OS, if available, with the memory
		1121	area starting at C<$offset> in the string and ending C<$length> bytes
		1122	later. If C<$length> is negative, counts from the end, and if C<$length>
		1123	is C<undef>, then it goes till the end of the string. The flags can be
		1124	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1125	C<IO::AIO::MS_SYNC>.
		1126
		1127	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1128
		1129	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1130	scalars.
		1131
		1132	It touches (reads or writes) all memory pages in the specified
		1133	range inside the scalar. All caveats and parameters are the same
		1134	as for C<aio_msync>, above, except for flags, which must be either
		1135	C<0> (which reads all pages and ensures they are instantiated) or
		1136	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1137	writing an octet from it, which dirties the page).
		1138
		1139	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1140
		1141	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1142	scalars.
		1143
		1144	It reads in all the pages of the underlying storage into memory (if any)
		1145	and locks them, so they are not getting swapped/paged out or removed.
		1146
		1147	If C<$length> is undefined, then the scalar will be locked till the end.
		1148
		1149	On systems that do not implement C<mlock>, this function returns C<-1>
		1150	and sets errno to C<ENOSYS>.
		1151
		1152	Note that the corresponding C<munlock> is synchronous and is
		1153	documented under L<MISCELLANEOUS FUNCTIONS>.
		1154
		1155	Example: open a file, mmap and mlock it - both will be undone when
		1156	C<$data> gets destroyed.
		1157
		1158	open my $fh, "<", $path or die "$path: $!";
		1159	my $data;
		1160	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1161	aio_mlock $data; # mlock in background
		1162
		1163	=item aio_mlockall $flags, $callback->($status)
		1164
		1165	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1166	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1167
		1168	On systems that do not implement C<mlockall>, this function returns C<-1>
		1169	and sets errno to C<ENOSYS>.
		1170
		1171	Note that the corresponding C<munlockall> is synchronous and is
		1172	documented under L<MISCELLANEOUS FUNCTIONS>.
		1173
		1174	Example: asynchronously lock all current and future pages into memory.
		1175
		1176	aio_mlockall IO::AIO::MCL_FUTURE;
573		1177
574	=item aio_group $callback->(...)	1178	=item aio_group $callback->(...)
575		1179
576	This is a very special aio request: Instead of doing something, it is a	1180	This is a very special aio request: Instead of doing something, it is a
577	container for other aio requests, which is useful if you want to bundle	1181	container for other aio requests, which is useful if you want to bundle
…		…
627	=item cancel $req	1231	=item cancel $req
628		1232
629	Cancels the request, if possible. Has the effect of skipping execution	1233	Cancels the request, if possible. Has the effect of skipping execution
630	when entering the B<execute> state and skipping calling the callback when	1234	when entering the B<execute> state and skipping calling the callback when
631	entering the the B<result> state, but will leave the request otherwise	1235	entering the the B<result> state, but will leave the request otherwise
632	untouched. That means that requests that currently execute will not be	1236	untouched (with the exception of readdir). That means that requests that
633	stopped and resources held by the request will not be freed prematurely.	1237	currently execute will not be stopped and resources held by the request
		1238	will not be freed prematurely.
634		1239
635	=item cb $req $callback->(...)	1240	=item cb $req $callback->(...)
636		1241
637	Replace (or simply set) the callback registered to the request.	1242	Replace (or simply set) the callback registered to the request.
638		1243
…		…
689	Their lifetime, simplified, looks like this: when they are empty, they	1294	Their lifetime, simplified, looks like this: when they are empty, they
690	will finish very quickly. If they contain only requests that are in the	1295	will finish very quickly. If they contain only requests that are in the
691	C<done> state, they will also finish. Otherwise they will continue to	1296	C<done> state, they will also finish. Otherwise they will continue to
692	exist.	1297	exist.
693		1298
694	That means after creating a group you have some time to add requests. And	1299	That means after creating a group you have some time to add requests
695	in the callbacks of those requests, you can add further requests to the	1300	(precisely before the callback has been invoked, which is only done within
696	group. And only when all those requests have finished will the the group	1301	the C<poll_cb>). And in the callbacks of those requests, you can add
697	itself finish.	1302	further requests to the group. And only when all those requests have
		1303	finished will the the group itself finish.
698		1304
699	=over 4	1305	=over 4
700		1306
701	=item add $grp ...	1307	=item add $grp ...
702		1308
…		…
711	=item $grp->cancel_subs	1317	=item $grp->cancel_subs
712		1318
713	Cancel all subrequests and clears any feeder, but not the group request	1319	Cancel all subrequests and clears any feeder, but not the group request
714	itself. Useful when you queued a lot of events but got a result early.	1320	itself. Useful when you queued a lot of events but got a result early.
715		1321
		1322	The group request will finish normally (you cannot add requests to the
		1323	group).
		1324
716	=item $grp->result (...)	1325	=item $grp->result (...)
717		1326
718	Set the result value(s) that will be passed to the group callback when all	1327	Set the result value(s) that will be passed to the group callback when all
719	subrequests have finished. By default, no argument will be passed.	1328	subrequests have finished and set the groups errno to the current value
		1329	of errno (just like calling C<errno> without an error number). By default,
		1330	no argument will be passed and errno is zero.
		1331
		1332	=item $grp->errno ([$errno])
		1333
		1334	Sets the group errno value to C<$errno>, or the current value of errno
		1335	when the argument is missing.
		1336
		1337	Every aio request has an associated errno value that is restored when
		1338	the callback is invoked. This method lets you change this value from its
		1339	default (0).
		1340
		1341	Calling C<result> will also set errno, so make sure you either set C<$!>
		1342	before the call to C<result>, or call c<errno> after it.
720		1343
721	=item feed $grp $callback->($grp)	1344	=item feed $grp $callback->($grp)
722		1345
723	Sets a feeder/generator on this group: every group can have an attached	1346	Sets a feeder/generator on this group: every group can have an attached
724	generator that generates requests if idle. The idea behind this is that,	1347	generator that generates requests if idle. The idea behind this is that,
725	although you could just queue as many requests as you want in a group,	1348	although you could just queue as many requests as you want in a group,
726	this might starve other requests for a potentially long time. For	1349	this might starve other requests for a potentially long time. For example,
727	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1350	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
728	requests, delaying any later requests for a long time.	1351	delaying any later requests for a long time.
729		1352
730	To avoid this, and allow incremental generation of requests, you can	1353	To avoid this, and allow incremental generation of requests, you can
731	instead a group and set a feeder on it that generates those requests. The	1354	instead a group and set a feeder on it that generates those requests. The
732	feed callback will be called whenever there are few enough (see C<limit>,	1355	feed callback will be called whenever there are few enough (see C<limit>,
733	below) requests active in the group itself and is expected to queue more	1356	below) requests active in the group itself and is expected to queue more
…		…
737	not impose any limits).	1360	not impose any limits).
738		1361
739	If the feed does not queue more requests when called, it will be	1362	If the feed does not queue more requests when called, it will be
740	automatically removed from the group.	1363	automatically removed from the group.
741		1364
742	If the feed limit is C<0>, it will be set to C<2> automatically.	1365	If the feed limit is C<0> when this method is called, it will be set to
		1366	C<2> automatically.
743		1367
744	Example:	1368	Example:
745		1369
746	# stat all files in @files, but only ever use four aio requests concurrently:	1370	# stat all files in @files, but only ever use four aio requests concurrently:
747		1371
…		…
759	Sets the feeder limit for the group: The feeder will be called whenever	1383	Sets the feeder limit for the group: The feeder will be called whenever
760	the group contains less than this many requests.	1384	the group contains less than this many requests.
761		1385
762	Setting the limit to C<0> will pause the feeding process.	1386	Setting the limit to C<0> will pause the feeding process.
763		1387
		1388	The default value for the limit is C<0>, but note that setting a feeder
		1389	automatically bumps it up to C<2>.
		1390
764	=back	1391	=back
765		1392
766	=head2 SUPPORT FUNCTIONS	1393	=head2 SUPPORT FUNCTIONS
767		1394
		1395	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		1396
768	=over 4	1397	=over 4
769		1398
770	=item $fileno = IO::AIO::poll_fileno	1399	=item $fileno = IO::AIO::poll_fileno
771		1400
772	Return the I<request result pipe file descriptor>. This filehandle must be	1401	Return the I<request result pipe file descriptor>. This filehandle must be
773	polled for reading by some mechanism outside this module (e.g. Event or	1402	polled for reading by some mechanism outside this module (e.g. EV, Glib,
774	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1403	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
775	to call C<poll_cb> to check the results.	1404	you have to call C<poll_cb> to check the results.
776		1405
777	See C<poll_cb> for an example.	1406	See C<poll_cb> for an example.
778		1407
779	=item IO::AIO::poll_cb	1408	=item IO::AIO::poll_cb
780		1409
781	Process all outstanding events on the result pipe. You have to call this	1410	Process some outstanding events on the result pipe. You have to call this
782	regularly. Returns the number of events processed. Returns immediately	1411	regularly. Returns C<0> if all events could be processed, or C<-1> if it
783	when no events are outstanding.	1412	returned earlier for whatever reason. Returns immediately when no events
		1413	are outstanding. The amount of events processed depends on the settings of
		1414	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
784		1415
785	If not all requests were processed for whatever reason, the filehandle	1416	If not all requests were processed for whatever reason, the filehandle
786	will still be ready when C<poll_cb> returns.	1417	will still be ready when C<poll_cb> returns, so normally you don't have to
		1418	do anything special to have it called later.
787		1419
788	Example: Install an Event watcher that automatically calls	1420	Example: Install an Event watcher that automatically calls
789	IO::AIO::poll_cb with high priority:	1421	IO::AIO::poll_cb with high priority (more examples can be found in the
		1422	SYNOPSIS section, at the top of this document):
790		1423
791	Event->io (fd => IO::AIO::poll_fileno,	1424	Event->io (fd => IO::AIO::poll_fileno,
792	poll => 'r', async => 1,	1425	poll => 'r', async => 1,
793	cb => \&IO::AIO::poll_cb);	1426	cb => \&IO::AIO::poll_cb);
794		1427
795	=item IO::AIO::poll_some $max_requests	1428	=item IO::AIO::poll_wait
796		1429
797	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests	1430	If there are any outstanding requests and none of them in the result
798	at a time.	1431	phase, wait till the result filehandle becomes ready for reading (simply
		1432	does a C<select> on the filehandle. This is useful if you want to
		1433	synchronously wait for some requests to finish).
799		1434
800	Useful if you want to ensure some level of interactiveness when perl is	1435	See C<nreqs> for an example.
801	not fast enough to process all requests in time.	1436
		1437	=item IO::AIO::poll
		1438
		1439	Waits until some requests have been handled.
		1440
		1441	Returns the number of requests processed, but is otherwise strictly
		1442	equivalent to:
		1443
		1444	IO::AIO::poll_wait, IO::AIO::poll_cb
		1445
		1446	=item IO::AIO::flush
		1447
		1448	Wait till all outstanding AIO requests have been handled.
		1449
		1450	Strictly equivalent to:
		1451
		1452	IO::AIO::poll_wait, IO::AIO::poll_cb
		1453	while IO::AIO::nreqs;
		1454
		1455	=item IO::AIO::max_poll_reqs $nreqs
		1456
		1457	=item IO::AIO::max_poll_time $seconds
		1458
		1459	These set the maximum number of requests (default C<0>, meaning infinity)
		1460	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1461	the maximum amount of time (default C<0>, meaning infinity) spent in
		1462	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1463	of time C<poll_cb> is allowed to use).
		1464
		1465	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1466	syscall per request processed, which is not normally a problem unless your
		1467	callbacks are really really fast or your OS is really really slow (I am
		1468	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1469
		1470	Setting these is useful if you want to ensure some level of
		1471	interactiveness when perl is not fast enough to process all requests in
		1472	time.
		1473
		1474	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
802		1475
803	Example: Install an Event watcher that automatically calls	1476	Example: Install an Event watcher that automatically calls
804	IO::AIO::poll_some with low priority, to ensure that other parts of the	1477	IO::AIO::poll_cb with low priority, to ensure that other parts of the
805	program get the CPU sometimes even under high AIO load.	1478	program get the CPU sometimes even under high AIO load.
806		1479
		1480	# try not to spend much more than 0.1s in poll_cb
		1481	IO::AIO::max_poll_time 0.1;
		1482
		1483	# use a low priority so other tasks have priority
807	Event->io (fd => IO::AIO::poll_fileno,	1484	Event->io (fd => IO::AIO::poll_fileno,
808	poll => 'r', nice => 1,	1485	poll => 'r', nice => 1,
809	cb => sub { IO::AIO::poll_some 256 });	1486	cb => &IO::AIO::poll_cb);
810		1487
811	=item IO::AIO::poll_wait	1488	=back
812		1489
813	Wait till the result filehandle becomes ready for reading (simply does a	1490	=head3 CONTROLLING THE NUMBER OF THREADS
814	C<select> on the filehandle. This is useful if you want to synchronously wait
815	for some requests to finish).
816		1491
817	See C<nreqs> for an example.	1492	=over
818
819	=item IO::AIO::nreqs
820
821	Returns the number of requests currently outstanding (i.e. for which their
822	callback has not been invoked yet).
823
824	Example: wait till there are no outstanding requests anymore:
825
826	IO::AIO::poll_wait, IO::AIO::poll_cb
827	while IO::AIO::nreqs;
828
829	=item IO::AIO::flush
830
831	Wait till all outstanding AIO requests have been handled.
832
833	Strictly equivalent to:
834
835	IO::AIO::poll_wait, IO::AIO::poll_cb
836	while IO::AIO::nreqs;
837
838	=item IO::AIO::poll
839
840	Waits until some requests have been handled.
841
842	Strictly equivalent to:
843
844	IO::AIO::poll_wait, IO::AIO::poll_cb
845	if IO::AIO::nreqs;
846		1493
847	=item IO::AIO::min_parallel $nthreads	1494	=item IO::AIO::min_parallel $nthreads
848		1495
849	Set the minimum number of AIO threads to C<$nthreads>. The current	1496	Set the minimum number of AIO threads to C<$nthreads>. The current
850	default is C<8>, which means eight asynchronous operations can execute	1497	default is C<8>, which means eight asynchronous operations can execute
851	concurrently at any one time (the number of outstanding requests,	1498	concurrently at any one time (the number of outstanding requests,
852	however, is unlimited).	1499	however, is unlimited).
853		1500
854	IO::AIO starts threads only on demand, when an AIO request is queued and	1501	IO::AIO starts threads only on demand, when an AIO request is queued and
855	no free thread exists.	1502	no free thread exists. Please note that queueing up a hundred requests can
		1503	create demand for a hundred threads, even if it turns out that everything
		1504	is in the cache and could have been processed faster by a single thread.
856		1505
857	It is recommended to keep the number of threads relatively low, as some	1506	It is recommended to keep the number of threads relatively low, as some
858	Linux kernel versions will scale negatively with the number of threads	1507	Linux kernel versions will scale negatively with the number of threads
859	(higher parallelity => MUCH higher latency). With current Linux 2.6	1508	(higher parallelity => MUCH higher latency). With current Linux 2.6
860	versions, 4-32 threads should be fine.	1509	versions, 4-32 threads should be fine.
…		…
874	This module automatically runs C<max_parallel 0> at program end, to ensure	1523	This module automatically runs C<max_parallel 0> at program end, to ensure
875	that all threads are killed and that there are no outstanding requests.	1524	that all threads are killed and that there are no outstanding requests.
876		1525
877	Under normal circumstances you don't need to call this function.	1526	Under normal circumstances you don't need to call this function.
878		1527
		1528	=item IO::AIO::max_idle $nthreads
		1529
		1530	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1531	threads that did not get a request to process within 10 seconds). That
		1532	means if a thread becomes idle while C<$nthreads> other threads are also
		1533	idle, it will free its resources and exit.
		1534
		1535	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1536	to allow for extremely high load situations, but want to free resources
		1537	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1538
		1539	The default is probably ok in most situations, especially if thread
		1540	creation is fast. If thread creation is very slow on your system you might
		1541	want to use larger values.
		1542
879	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1543	=item IO::AIO::max_outstanding $maxreqs
880		1544
881	This is a very bad function to use in interactive programs because it	1545	This is a very bad function to use in interactive programs because it
882	blocks, and a bad way to reduce concurrency because it is inexact: Better	1546	blocks, and a bad way to reduce concurrency because it is inexact: Better
883	use an C<aio_group> together with a feed callback.	1547	use an C<aio_group> together with a feed callback.
884		1548
885	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1549	Sets the maximum number of outstanding requests to C<$nreqs>. If you
886	to queue up more than this number of requests, the next call to the	1550	do queue up more than this number of requests, the next call to the
887	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1551	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
888	function will block until the limit is no longer exceeded.	1552	function will block until the limit is no longer exceeded.
889		1553
890	The default value is very large, so there is no practical limit on the	1554	The default value is very large, so there is no practical limit on the
891	number of outstanding requests.	1555	number of outstanding requests.
892		1556
893	You can still queue as many requests as you want. Therefore,	1557	You can still queue as many requests as you want. Therefore,
894	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1558	C<max_outstanding> is mainly useful in simple scripts (with low values) or
895	as a stop gap to shield against fatal memory overflow (with large values).	1559	as a stop gap to shield against fatal memory overflow (with large values).
896		1560
897	=back	1561	=back
898		1562
		1563	=head3 STATISTICAL INFORMATION
		1564
		1565	=over
		1566
		1567	=item IO::AIO::nreqs
		1568
		1569	Returns the number of requests currently in the ready, execute or pending
		1570	states (i.e. for which their callback has not been invoked yet).
		1571
		1572	Example: wait till there are no outstanding requests anymore:
		1573
		1574	IO::AIO::poll_wait, IO::AIO::poll_cb
		1575	while IO::AIO::nreqs;
		1576
		1577	=item IO::AIO::nready
		1578
		1579	Returns the number of requests currently in the ready state (not yet
		1580	executed).
		1581
		1582	=item IO::AIO::npending
		1583
		1584	Returns the number of requests currently in the pending state (executed,
		1585	but not yet processed by poll_cb).
		1586
		1587	=back
		1588
		1589	=head3 MISCELLANEOUS FUNCTIONS
		1590
		1591	IO::AIO implements some functions that might be useful, but are not
		1592	asynchronous.
		1593
		1594	=over 4
		1595
		1596	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1597
		1598	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1599	but is blocking (this makes most sense if you know the input data is
		1600	likely cached already and the output filehandle is set to non-blocking
		1601	operations).
		1602
		1603	Returns the number of bytes copied, or C<-1> on error.
		1604
		1605	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1606
		1607	Simply calls the C<posix_fadvise> function (see its
		1608	manpage for details). The following advice constants are
		1609	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1610	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1611	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1612
		1613	On systems that do not implement C<posix_fadvise>, this function returns
		1614	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1615
		1616	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1617
		1618	Simply calls the C<posix_madvise> function (see its
		1619	manpage for details). The following advice constants are
		1620	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1621	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1622
		1623	On systems that do not implement C<posix_madvise>, this function returns
		1624	ENOSYS, otherwise the return value of C<posix_madvise>.
		1625
		1626	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1627
		1628	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1629	$scalar (see its manpage for details). The following protect
		1630	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1631	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1632
		1633	On systems that do not implement C<mprotect>, this function returns
		1634	ENOSYS, otherwise the return value of C<mprotect>.
		1635
		1636	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1637
		1638	Memory-maps a file (or anonymous memory range) and attaches it to the
		1639	given C<$scalar>, which will act like a string scalar.
		1640
		1641	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1642	change the string length, and most read-only operations such as copying it
		1643	or searching it with regexes and so on.
		1644
		1645	Anything else is unsafe and will, at best, result in memory leaks.
		1646
		1647	The memory map associated with the C<$scalar> is automatically removed
		1648	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1649	C<IO::AIO::munmap> functions are called.
		1650
		1651	This calls the C<mmap>(2) function internally. See your system's manual
		1652	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1653
		1654	The C<$length> must be larger than zero and smaller than the actual
		1655	filesize.
		1656
		1657	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1658	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1659
		1660	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1661	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1662	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1663	(which is set to C<MAP_ANON> if your system only provides this
		1664	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1665	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1666	C<IO::AIO::MAP_NONBLOCK>
		1667
		1668	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1669
		1670	C<$offset> is the offset from the start of the file - it generally must be
		1671	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1672
		1673	Example:
		1674
		1675	use Digest::MD5;
		1676	use IO::AIO;
		1677
		1678	open my $fh, "<verybigfile"
		1679	or die "$!";
		1680
		1681	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1682	or die "verybigfile: $!";
		1683
		1684	my $fast_md5 = md5 $data;
		1685
		1686	=item IO::AIO::munmap $scalar
		1687
		1688	Removes a previous mmap and undefines the C<$scalar>.
		1689
		1690	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1691
		1692	Calls the C<munlock> function, undoing the effects of a previous
		1693	C<aio_mlock> call (see its description for details).
		1694
		1695	=item IO::AIO::munlockall
		1696
		1697	Calls the C<munlockall> function.
		1698
		1699	On systems that do not implement C<munlockall>, this function returns
		1700	ENOSYS, otherwise the return value of C<munlockall>.
		1701
		1702	=back
		1703
899	=cut	1704	=cut
900		1705
901	# support function to convert a fd into a perl filehandle
902	sub _fd2fh {
903	return undef if $_[0] < 0;
904
905	# try to generate nice filehandles
906	my $sym = "IO::AIO::fd#$_[0]";
907	local *$sym;
908
909	open *$sym, "+<&=$_[0]" # usually works under any unix
910	or open *$sym, "<&=$_[0]" # cygwin needs this
911	or open *$sym, ">&=$_[0]" # or this
912	or return undef;
913
914	*$sym
915	}
916
917	min_parallel 8;	1706	min_parallel 8;
918		1707
919	END {	1708	END { flush }
920	max_parallel 0;
921	}
922		1709
923	1;	1710	1;
		1711
		1712	=head1 EVENT LOOP INTEGRATION
		1713
		1714	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1715	automatically into many event loops:
		1716
		1717	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1718	use AnyEvent::AIO;
		1719
		1720	You can also integrate IO::AIO manually into many event loops, here are
		1721	some examples of how to do this:
		1722
		1723	# EV integration
		1724	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1725
		1726	# Event integration
		1727	Event->io (fd => IO::AIO::poll_fileno,
		1728	poll => 'r',
		1729	cb => \&IO::AIO::poll_cb);
		1730
		1731	# Glib/Gtk2 integration
		1732	add_watch Glib::IO IO::AIO::poll_fileno,
		1733	in => sub { IO::AIO::poll_cb; 1 };
		1734
		1735	# Tk integration
		1736	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1737	readable => \&IO::AIO::poll_cb);
		1738
		1739	# Danga::Socket integration
		1740	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1741	\&IO::AIO::poll_cb);
924		1742
925	=head2 FORK BEHAVIOUR	1743	=head2 FORK BEHAVIOUR
926		1744
927	This module should do "the right thing" when the process using it forks:	1745	This module should do "the right thing" when the process using it forks:
928		1746
…		…
946	bytes of memory. In addition, stat requests need a stat buffer (possibly	1764	bytes of memory. In addition, stat requests need a stat buffer (possibly
947	a few hundred bytes), readdir requires a result buffer and so on. Perl	1765	a few hundred bytes), readdir requires a result buffer and so on. Perl
948	scalars and other data passed into aio requests will also be locked and	1766	scalars and other data passed into aio requests will also be locked and
949	will consume memory till the request has entered the done state.	1767	will consume memory till the request has entered the done state.
950		1768
951	This is now awfully much, so queuing lots of requests is not usually a	1769	This is not awfully much, so queuing lots of requests is not usually a
952	problem.	1770	problem.
953		1771
954	Per-thread usage:	1772	Per-thread usage:
955		1773
956	In the execution phase, some aio requests require more memory for	1774	In the execution phase, some aio requests require more memory for
…		…
961		1779
962	Known bugs will be fixed in the next release.	1780	Known bugs will be fixed in the next release.
963		1781
964	=head1 SEE ALSO	1782	=head1 SEE ALSO
965		1783
966	L<Coro::AIO>.	1784	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1785	more natural syntax.
967		1786
968	=head1 AUTHOR	1787	=head1 AUTHOR
969		1788
970	Marc Lehmann <schmorp@schmorp.de>	1789	Marc Lehmann <schmorp@schmorp.de>
971	http://home.schmorp.de/	1790	http://home.schmorp.de/

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