ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.96 by root, Fri Dec 22 04:05:50 2006 UTC vs.
Revision 1.195 by root, Fri May 27 19:56:31 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 = '2.21';	173	our $VERSION = '3.9';
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
200	aio_move aio_copy aio_group aio_nop aio_mknod);	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
		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.
…		…
290	list. They are the same as used by C<sysopen>.	353	list. They are the same as used by C<sysopen>.
291		354
292	Likewise, C<$mode> specifies the mode of the newly created file, if it	355	Likewise, C<$mode> specifies the mode of the newly created file, if it
293	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	356	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
294	except that it is mandatory (i.e. use C<0> if you don't create new files,	357	except that it is mandatory (i.e. use C<0> if you don't create new files,
295	and C<0666> or C<0777> if you do).	358	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		359	by the umask in effect then the request is being executed, so better never
		360	change the umask.
296		361
297	Example:	362	Example:
298		363
299	aio_open "/etc/passwd", O_RDONLY, 0, sub {	364	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
300	if ($_[0]) {	365	if ($_[0]) {
301	print "open successful, fh is $_[0]\n";	366	print "open successful, fh is $_[0]\n";
302	...	367	...
303	} else {	368	} else {
304	die "open failed: $!\n";	369	die "open failed: $!\n";
305	}	370	}
306	};	371	};
307		372
		373	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		374	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		375	following POSIX and non-POSIX constants are available (missing ones on
		376	your system are, as usual, C<0>):
		377
		378	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		379	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		380	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		381
		382
308	=item aio_close $fh, $callback->($status)	383	=item aio_close $fh, $callback->($status)
309		384
310	Asynchronously close a file and call the callback with the result	385	Asynchronously close a file and call the callback with the result
311	code. I<WARNING:> although accepted, you should not pass in a perl	386	code.
312	filehandle here, as perl will likely close the file descriptor another
313	time when the filehandle is destroyed. Normally, you can safely call perls
314	C<close> or just let filehandles go out of scope.
315		387
316	This is supposed to be a bug in the API, so that might change. It's	388	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
317	therefore best to avoid this function.	389	closing the file descriptor associated with the filehandle itself.
		390
		391	Therefore, C<aio_close> will not close the filehandle - instead it will
		392	use dup2 to overwrite the file descriptor with the write-end of a pipe
		393	(the pipe fd will be created on demand and will be cached).
		394
		395	Or in other words: the file descriptor will be closed, but it will not be
		396	free for reuse until the perl filehandle is closed.
		397
		398	=cut
318		399
319	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	400	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320		401
321	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	402	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322		403
323	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	404	Reads or writes C<$length> bytes from or to the specified C<$fh> and
324	into the scalar given by C<data> and offset C<dataoffset> and calls the	405	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
325	callback without the actual number of bytes read (or -1 on error, just	406	and calls the callback without the actual number of bytes read (or -1 on
326	like the syscall).	407	error, just like the syscall).
		408
		409	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		410	offset plus the actual number of bytes read.
		411
		412	If C<$offset> is undefined, then the current file descriptor offset will
		413	be used (and updated), otherwise the file descriptor offset will not be
		414	changed by these calls.
		415
		416	If C<$length> is undefined in C<aio_write>, use the remaining length of
		417	C<$data>.
		418
		419	If C<$dataoffset> is less than zero, it will be counted from the end of
		420	C<$data>.
327		421
328	The C<$data> scalar I<MUST NOT> be modified in any way while the request	422	The C<$data> scalar I<MUST NOT> be modified in any way while the request
329	is outstanding. Modifying it can result in segfaults or WW3 (if the	423	is outstanding. Modifying it can result in segfaults or World War III (if
330	necessary/optional hardware is installed).	424	the necessary/optional hardware is installed).
331		425
332	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	426	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
333	offset C<0> within the scalar:	427	offset C<0> within the scalar:
334		428
335	aio_read $fh, 7, 15, $buffer, 0, sub {	429	aio_read $fh, 7, 15, $buffer, 0, sub {
336	$_[0] > 0 or die "read error: $!";	430	$_[0] > 0 or die "read error: $!";
337	print "read $_[0] bytes: <$buffer>\n";	431	print "read $_[0] bytes: <$buffer>\n";
338	};	432	};
		433
339		434
340	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	435	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
341		436
342	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	437	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
343	reading at byte offset C<$in_offset>, and starts writing at the current	438	reading at byte offset C<$in_offset>, and starts writing at the current
344	file offset of C<$out_fh>. Because of that, it is not safe to issue more	439	file offset of C<$out_fh>. Because of that, it is not safe to issue more
345	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	440	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
346	other.	441	other.
347		442
		443	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		444	are written, and there is no way to find out how many bytes have been read
		445	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of
		446	bytes written to C<$out_fh>. Only if the result value equals C<$length>
		447	one can assume that C<$length> bytes have been read.
		448
		449	Unlike with other C<aio_> functions, it makes a lot of sense to use
		450	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		451	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		452	the socket I/O will be non-blocking. Note, however, that you can run into
		453	a trap where C<aio_sendfile> reads some data with readahead, then fails
		454	to write all data, and when the socket is ready the next time, the data
		455	in the cache is already lost, forcing C<aio_sendfile> to again hit the
		456	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage
		457	much better.
		458
348	This call tries to make use of a native C<sendfile> syscall to provide	459	This call tries to make use of a native C<sendfile> syscall to provide
349	zero-copy operation. For this to work, C<$out_fh> should refer to a	460	zero-copy operation. For this to work, C<$out_fh> should refer to a
350	socket, and C<$in_fh> should refer to mmap'able file.	461	socket, and C<$in_fh> should refer to an mmap'able file.
351		462
352	If the native sendfile call fails or is not implemented, it will be	463	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		464	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
353	emulated, so you can call C<aio_sendfile> on any type of filehandle	465	it will be emulated, so you can call C<aio_sendfile> on any type of
354	regardless of the limitations of the operating system.	466	filehandle regardless of the limitations of the operating system.
355		467
356	Please note, however, that C<aio_sendfile> can read more bytes from
357	C<$in_fh> than are written, and there is no way to find out how many
358	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
359	provides the number of bytes written to C<$out_fh>. Only if the result
360	value equals C<$length> one can assume that C<$length> bytes have been
361	read.
362		468
363	=item aio_readahead $fh,$offset,$length, $callback->($retval)	469	=item aio_readahead $fh,$offset,$length, $callback->($retval)
364		470
365	C<aio_readahead> populates the page cache with data from a file so that	471	C<aio_readahead> populates the page cache with data from a file so that
366	subsequent reads from that file will not block on disk I/O. The C<$offset>	472	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
372	file. The current file offset of the file is left unchanged.	478	file. The current file offset of the file is left unchanged.
373		479
374	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	480	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
375	emulated by simply reading the data, which would have a similar effect.	481	emulated by simply reading the data, which would have a similar effect.
376		482
		483
377	=item aio_stat $fh_or_path, $callback->($status)	484	=item aio_stat $fh_or_path, $callback->($status)
378		485
379	=item aio_lstat $fh, $callback->($status)	486	=item aio_lstat $fh, $callback->($status)
380		487
381	Works like perl's C<stat> or C<lstat> in void context. The callback will	488	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
386	for an explanation.	493	for an explanation.
387		494
388	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	495	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
389	error when stat'ing a large file, the results will be silently truncated	496	error when stat'ing a large file, the results will be silently truncated
390	unless perl itself is compiled with large file support.	497	unless perl itself is compiled with large file support.
		498
		499	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		500	following constants and functions (if not implemented, the constants will
		501	be C<0> and the functions will either C<croak> or fall back on traditional
		502	behaviour).
		503
		504	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		505	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		506	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
391		507
392	Example: Print the length of F</etc/passwd>:	508	Example: Print the length of F</etc/passwd>:
393		509
394	aio_stat "/etc/passwd", sub {	510	aio_stat "/etc/passwd", sub {
395	$_[0] and die "stat failed: $!";	511	$_[0] and die "stat failed: $!";
396	print "size is ", -s _, "\n";	512	print "size is ", -s _, "\n";
397	};	513	};
398		514
		515
		516	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		517
		518	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		519	whether a file handle or path was passed.
		520
		521	On success, the callback is passed a hash reference with the following
		522	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		523	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		524	is passed.
		525
		526	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		527	C<ST_NOSUID>.
		528
		529	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		530	their correct value when available, or to C<0> on systems that do
		531	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		532	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		533	C<ST_NODIRATIME> and C<ST_RELATIME>.
		534
		535	Example: stat C</wd> and dump out the data if successful.
		536
		537	aio_statvfs "/wd", sub {
		538	my $f = $_[0]
		539	or die "statvfs: $!";
		540
		541	use Data::Dumper;
		542	say Dumper $f;
		543	};
		544
		545	# result:
		546	{
		547	bsize => 1024,
		548	bfree => 4333064312,
		549	blocks => 10253828096,
		550	files => 2050765568,
		551	flag => 4096,
		552	favail => 2042092649,
		553	bavail => 4333064312,
		554	ffree => 2042092649,
		555	namemax => 255,
		556	frsize => 1024,
		557	fsid => 1810
		558	}
		559
		560
		561	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		562
		563	Works like perl's C<utime> function (including the special case of $atime
		564	and $mtime being undef). Fractional times are supported if the underlying
		565	syscalls support them.
		566
		567	When called with a pathname, uses utimes(2) if available, otherwise
		568	utime(2). If called on a file descriptor, uses futimes(2) if available,
		569	otherwise returns ENOSYS, so this is not portable.
		570
		571	Examples:
		572
		573	# set atime and mtime to current time (basically touch(1)):
		574	aio_utime "path", undef, undef;
		575	# set atime to current time and mtime to beginning of the epoch:
		576	aio_utime "path", time, undef; # undef==0
		577
		578
		579	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		580
		581	Works like perl's C<chown> function, except that C<undef> for either $uid
		582	or $gid is being interpreted as "do not change" (but -1 can also be used).
		583
		584	Examples:
		585
		586	# same as "chown root path" in the shell:
		587	aio_chown "path", 0, -1;
		588	# same as above:
		589	aio_chown "path", 0, undef;
		590
		591
		592	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		593
		594	Works like truncate(2) or ftruncate(2).
		595
		596
		597	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		598
		599	Works like perl's C<chmod> function.
		600
		601
399	=item aio_unlink $pathname, $callback->($status)	602	=item aio_unlink $pathname, $callback->($status)
400		603
401	Asynchronously unlink (delete) a file and call the callback with the	604	Asynchronously unlink (delete) a file and call the callback with the
402	result code.	605	result code.
403		606
		607
404	=item aio_mknod $path, $mode, $dev, $callback->($status)	608	=item aio_mknod $path, $mode, $dev, $callback->($status)
405		609
406	[EXPERIMENTAL]	610	[EXPERIMENTAL]
407		611
408	Asynchronously create a device node (or fifo). See mknod(2).	612	Asynchronously create a device node (or fifo). See mknod(2).
409		613
410	The only (POSIX-) portable way of calling this function is:	614	The only (POSIX-) portable way of calling this function is:
411		615
412	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	616	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		617
		618	See C<aio_stat> for info about some potentially helpful extra constants
		619	and functions.
413		620
414	=item aio_link $srcpath, $dstpath, $callback->($status)	621	=item aio_link $srcpath, $dstpath, $callback->($status)
415		622
416	Asynchronously create a new link to the existing object at C<$srcpath> at	623	Asynchronously create a new link to the existing object at C<$srcpath> at
417	the path C<$dstpath> and call the callback with the result code.	624	the path C<$dstpath> and call the callback with the result code.
418		625
		626
419	=item aio_symlink $srcpath, $dstpath, $callback->($status)	627	=item aio_symlink $srcpath, $dstpath, $callback->($status)
420		628
421	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	629	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
422	the path C<$dstpath> and call the callback with the result code.	630	the path C<$dstpath> and call the callback with the result code.
		631
423		632
424	=item aio_readlink $path, $callback->($link)	633	=item aio_readlink $path, $callback->($link)
425		634
426	Asynchronously read the symlink specified by C<$path> and pass it to	635	Asynchronously read the symlink specified by C<$path> and pass it to
427	the callback. If an error occurs, nothing or undef gets passed to the	636	the callback. If an error occurs, nothing or undef gets passed to the
428	callback.	637	callback.
429		638
		639
430	=item aio_rename $srcpath, $dstpath, $callback->($status)	640	=item aio_rename $srcpath, $dstpath, $callback->($status)
431		641
432	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	642	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
433	rename(2) and call the callback with the result code.	643	rename(2) and call the callback with the result code.
434		644
		645
		646	=item aio_mkdir $pathname, $mode, $callback->($status)
		647
		648	Asynchronously mkdir (create) a directory and call the callback with
		649	the result code. C<$mode> will be modified by the umask at the time the
		650	request is executed, so do not change your umask.
		651
		652
435	=item aio_rmdir $pathname, $callback->($status)	653	=item aio_rmdir $pathname, $callback->($status)
436		654
437	Asynchronously rmdir (delete) a directory and call the callback with the	655	Asynchronously rmdir (delete) a directory and call the callback with the
438	result code.	656	result code.
		657
439		658
440	=item aio_readdir $pathname, $callback->($entries)	659	=item aio_readdir $pathname, $callback->($entries)
441		660
442	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	661	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
443	directory (i.e. opendir + readdir + closedir). The entries will not be	662	directory (i.e. opendir + readdir + closedir). The entries will not be
444	sorted, and will B<NOT> include the C<.> and C<..> entries.	663	sorted, and will B<NOT> include the C<.> and C<..> entries.
445		664
446	The callback a single argument which is either C<undef> or an array-ref	665	The callback is passed a single argument which is either C<undef> or an
447	with the filenames.	666	array-ref with the filenames.
		667
		668
		669	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		670
		671	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		672	behaviour and output format. In case of an error, C<$entries> will be
		673	C<undef>.
		674
		675	The flags are a combination of the following constants, ORed together (the
		676	flags will also be passed to the callback, possibly modified):
		677
		678	=over 4
		679
		680	=item IO::AIO::READDIR_DENTS
		681
		682	When this flag is off, then the callback gets an arrayref consisting of
		683	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		684	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		685	entry in more detail.
		686
		687	C<$name> is the name of the entry.
		688
		689	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		690
		691	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		692	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		693	C<IO::AIO::DT_WHT>.
		694
		695	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		696	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		697	scalars are read-only: you can not modify them.
		698
		699	C<$inode> is the inode number (which might not be exact on systems with 64
		700	bit inode numbers and 32 bit perls). This field has unspecified content on
		701	systems that do not deliver the inode information.
		702
		703	=item IO::AIO::READDIR_DIRS_FIRST
		704
		705	When this flag is set, then the names will be returned in an order where
		706	likely directories come first, in optimal stat order. This is useful when
		707	you need to quickly find directories, or you want to find all directories
		708	while avoiding to stat() each entry.
		709
		710	If the system returns type information in readdir, then this is used
		711	to find directories directly. Otherwise, likely directories are names
		712	beginning with ".", or otherwise names with no dots, of which names with
		713	short names are tried first.
		714
		715	=item IO::AIO::READDIR_STAT_ORDER
		716
		717	When this flag is set, then the names will be returned in an order
		718	suitable for stat()'ing each one. That is, when you plan to stat()
		719	all files in the given directory, then the returned order will likely
		720	be fastest.
		721
		722	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		723	the likely dirs come first, resulting in a less optimal stat order.
		724
		725	=item IO::AIO::READDIR_FOUND_UNKNOWN
		726
		727	This flag should not be set when calling C<aio_readdirx>. Instead, it
		728	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		729	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		730	C<$type>'s are known, which can be used to speed up some algorithms.
		731
		732	=back
		733
		734
		735	=item aio_load $path, $data, $callback->($status)
		736
		737	This is a composite request that tries to fully load the given file into
		738	memory. Status is the same as with aio_read.
		739
		740	=cut
		741
		742	sub aio_load($$;$) {
		743	my ($path, undef, $cb) = @_;
		744	my $data = \$_[1];
		745
		746	my $pri = aioreq_pri;
		747	my $grp = aio_group $cb;
		748
		749	aioreq_pri $pri;
		750	add $grp aio_open $path, O_RDONLY, 0, sub {
		751	my $fh = shift
		752	or return $grp->result (-1);
		753
		754	aioreq_pri $pri;
		755	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		756	$grp->result ($_[0]);
		757	};
		758	};
		759
		760	$grp
		761	}
448		762
449	=item aio_copy $srcpath, $dstpath, $callback->($status)	763	=item aio_copy $srcpath, $dstpath, $callback->($status)
450		764
451	Try to copy the I<file> (directories not supported as either source or	765	Try to copy the I<file> (directories not supported as either source or
452	destination) from C<$srcpath> to C<$dstpath> and call the callback with	766	destination) from C<$srcpath> to C<$dstpath> and call the callback with
453	the C<0> (error) or C<-1> ok.	767	a status of C<0> (ok) or C<-1> (error, see C<$!>).
454		768
455	This is a composite request that it creates the destination file with	769	This is a composite request that creates the destination file with
456	mode 0200 and copies the contents of the source file into it using	770	mode 0200 and copies the contents of the source file into it using
457	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	771	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
458	uid/gid, in that order.	772	uid/gid, in that order.
459		773
460	If an error occurs, the partial destination file will be unlinked, if	774	If an error occurs, the partial destination file will be unlinked, if
…		…
462	errors are being ignored.	776	errors are being ignored.
463		777
464	=cut	778	=cut
465		779
466	sub aio_copy($$;$) {	780	sub aio_copy($$;$) {
467	aio_block {
468	my ($src, $dst, $cb) = @_;	781	my ($src, $dst, $cb) = @_;
469		782
470	my $pri = aioreq_pri;	783	my $pri = aioreq_pri;
471	my $grp = aio_group $cb;	784	my $grp = aio_group $cb;
472		785
473	aioreq_pri $pri;	786	aioreq_pri $pri;
474	add $grp aio_open $src, O_RDONLY, 0, sub {	787	add $grp aio_open $src, O_RDONLY, 0, sub {
475	if (my $src_fh = $_[0]) {	788	if (my $src_fh = $_[0]) {
476	my @stat = stat $src_fh;	789	my @stat = stat $src_fh; # hmm, might block over nfs?
477		790
478	aioreq_pri $pri;	791	aioreq_pri $pri;
479	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	792	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
480	if (my $dst_fh = $_[0]) {	793	if (my $dst_fh = $_[0]) {
481	aioreq_pri $pri;	794	aioreq_pri $pri;
482	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	795	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
483	if ($_[0] == $stat[7]) {	796	if ($_[0] == $stat[7]) {
484	$grp->result (0);	797	$grp->result (0);
485	close $src_fh;	798	close $src_fh;
486		799
487	# those should not normally block. should. should.
488	utime $stat[8], $stat[9], $dst;
489	chmod $stat[2] & 07777, $dst_fh;
490	chown $stat[4], $stat[5], $dst_fh;
491	close $dst_fh;
492	} else {	800	my $ch = sub {
493	$grp->result (-1);
494	close $src_fh;
495	close $dst_fh;
496
497	aioreq $pri;	801	aioreq_pri $pri;
		802	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		803	aioreq_pri $pri;
		804	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		805	aioreq_pri $pri;
498	add $grp aio_unlink $dst;	806	add $grp aio_close $dst_fh;
		807	}
		808	};
499	}	809	};
		810
		811	aioreq_pri $pri;
		812	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		813	if ($_[0] < 0 && $! == ENOSYS) {
		814	aioreq_pri $pri;
		815	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		816	} else {
		817	$ch->();
		818	}
		819	};
		820	} else {
		821	$grp->result (-1);
		822	close $src_fh;
		823	close $dst_fh;
		824
		825	aioreq $pri;
		826	add $grp aio_unlink $dst;
500	};	827	}
501	} else {
502	$grp->result (-1);
503	}	828	};
		829	} else {
		830	$grp->result (-1);
504	},	831	}
505
506	} else {
507	$grp->result (-1);
508	}	832	},
		833
		834	} else {
		835	$grp->result (-1);
509	};	836	}
510
511	$grp
512	}	837	};
		838
		839	$grp
513	}	840	}
514		841
515	=item aio_move $srcpath, $dstpath, $callback->($status)	842	=item aio_move $srcpath, $dstpath, $callback->($status)
516		843
517	Try to move the I<file> (directories not supported as either source or	844	Try to move the I<file> (directories not supported as either source or
518	destination) from C<$srcpath> to C<$dstpath> and call the callback with	845	destination) from C<$srcpath> to C<$dstpath> and call the callback with
519	the C<0> (error) or C<-1> ok.	846	a status of C<0> (ok) or C<-1> (error, see C<$!>).
520		847
521	This is a composite request that tries to rename(2) the file first. If	848	This is a composite request that tries to rename(2) the file first; if
522	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	849	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
523	that is successful, unlinking the C<$srcpath>.	850	that is successful, unlinks the C<$srcpath>.
524		851
525	=cut	852	=cut
526		853
527	sub aio_move($$;$) {	854	sub aio_move($$;$) {
528	aio_block {
529	my ($src, $dst, $cb) = @_;	855	my ($src, $dst, $cb) = @_;
530		856
531	my $pri = aioreq_pri;	857	my $pri = aioreq_pri;
532	my $grp = aio_group $cb;	858	my $grp = aio_group $cb;
533		859
534	aioreq_pri $pri;	860	aioreq_pri $pri;
535	add $grp aio_rename $src, $dst, sub {	861	add $grp aio_rename $src, $dst, sub {
536	if ($_[0] && $! == EXDEV) {	862	if ($_[0] && $! == EXDEV) {
537	aioreq_pri $pri;	863	aioreq_pri $pri;
538	add $grp aio_copy $src, $dst, sub {	864	add $grp aio_copy $src, $dst, sub {
539	$grp->result ($_[0]);
540
541	if (!$_[0]) {
542	aioreq_pri $pri;
543	add $grp aio_unlink $src;
544	}
545	};
546	} else {
547	$grp->result ($_[0]);	865	$grp->result ($_[0]);
		866
		867	if (!$_[0]) {
		868	aioreq_pri $pri;
		869	add $grp aio_unlink $src;
		870	}
548	}	871	};
		872	} else {
		873	$grp->result ($_[0]);
549	};	874	}
550
551	$grp
552	}	875	};
		876
		877	$grp
553	}	878	}
554		879
555	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	880	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
556		881
557	Scans a directory (similar to C<aio_readdir>) but additionally tries to	882	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
577		902
578	Implementation notes.	903	Implementation notes.
579		904
580	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	905	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
581		906
		907	If readdir returns file type information, then this is used directly to
		908	find directories.
		909
582	After reading the directory, the modification time, size etc. of the	910	Otherwise, after reading the directory, the modification time, size etc.
583	directory before and after the readdir is checked, and if they match (and	911	of the directory before and after the readdir is checked, and if they
584	isn't the current time), the link count will be used to decide how many	912	match (and isn't the current time), the link count will be used to decide
585	entries are directories (if >= 2). Otherwise, no knowledge of the number	913	how many entries are directories (if >= 2). Otherwise, no knowledge of the
586	of subdirectories will be assumed.	914	number of subdirectories will be assumed.
587		915
588	Then entries will be sorted into likely directories (everything without	916	Then entries will be sorted into likely directories a non-initial dot
589	a non-initial dot currently) and likely non-directories (everything	917	currently) and likely non-directories (see C<aio_readdirx>). Then every
590	else). Then every entry plus an appended C</.> will be C<stat>'ed,	918	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
591	likely directories first. If that succeeds, it assumes that the entry	919	in order of their inode numbers. If that succeeds, it assumes that the
592	is a directory or a symlink to directory (which will be checked	920	entry is a directory or a symlink to directory (which will be checked
593	seperately). This is often faster than stat'ing the entry itself because	921	seperately). This is often faster than stat'ing the entry itself because
594	filesystems might detect the type of the entry without reading the inode	922	filesystems might detect the type of the entry without reading the inode
595	data (e.g. ext2fs filetype feature).	923	data (e.g. ext2fs filetype feature), even on systems that cannot return
		924	the filetype information on readdir.
596		925
597	If the known number of directories (link count - 2) has been reached, the	926	If the known number of directories (link count - 2) has been reached, the
598	rest of the entries is assumed to be non-directories.	927	rest of the entries is assumed to be non-directories.
599		928
600	This only works with certainty on POSIX (= UNIX) filesystems, which	929	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
604	as those tend to return 0 or 1 as link counts, which disables the	933	as those tend to return 0 or 1 as link counts, which disables the
605	directory counting heuristic.	934	directory counting heuristic.
606		935
607	=cut	936	=cut
608		937
609	sub aio_scandir($$$) {	938	sub aio_scandir($$;$) {
610	aio_block {
611	my ($path, $maxreq, $cb) = @_;	939	my ($path, $maxreq, $cb) = @_;
612		940
613	my $pri = aioreq_pri;	941	my $pri = aioreq_pri;
614		942
615	my $grp = aio_group $cb;	943	my $grp = aio_group $cb;
616		944
617	$maxreq = 4 if $maxreq <= 0;	945	$maxreq = 4 if $maxreq <= 0;
618		946
619	# stat once	947	# stat once
		948	aioreq_pri $pri;
		949	add $grp aio_stat $path, sub {
		950	return $grp->result () if $_[0];
		951	my $now = time;
		952	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		953
		954	# read the directory entries
620	aioreq_pri $pri;	955	aioreq_pri $pri;
621	add $grp aio_stat $path, sub {	956	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		957	my $entries = shift
622	return $grp->result () if $_[0];	958	or return $grp->result ();
623	my $now = time;
624	my $hash1 = join ":", (stat _)[0,1,3,7,9];
625		959
626	# read the directory entries	960	# stat the dir another time
627	aioreq_pri $pri;	961	aioreq_pri $pri;
628	add $grp aio_readdir $path, sub {
629	my $entries = shift
630	or return $grp->result ();
631
632	# stat the dir another time
633	aioreq_pri $pri;
634	add $grp aio_stat $path, sub {	962	add $grp aio_stat $path, sub {
635	my $hash2 = join ":", (stat _)[0,1,3,7,9];	963	my $hash2 = join ":", (stat _)[0,1,3,7,9];
636		964
637	my $ndirs;	965	my $ndirs;
638		966
639	# take the slow route if anything looks fishy	967	# take the slow route if anything looks fishy
640	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	968	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
641	$ndirs = -1;	969	$ndirs = -1;
642	} else {	970	} else {
643	# if nlink == 2, we are finished	971	# if nlink == 2, we are finished
644	# on non-posix-fs's, we rely on nlink < 2	972	# for non-posix-fs's, we rely on nlink < 2
645	$ndirs = (stat _)[3] - 2	973	$ndirs = (stat _)[3] - 2
646	or return $grp->result ([], $entries);	974	or return $grp->result ([], $entries);
647	}	975	}
648		976
649	# sort into likely dirs and likely nondirs
650	# dirs == files without ".", short entries first
651	$entries = [map $_->[0],
652	sort { $b->[1] cmp $a->[1] }
653	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
654	@$entries];
655
656	my (@dirs, @nondirs);	977	my (@dirs, @nondirs);
657		978
658	my $statgrp = add $grp aio_group sub {	979	my $statgrp = add $grp aio_group sub {
659	$grp->result (\@dirs, \@nondirs);	980	$grp->result (\@dirs, \@nondirs);
660	};	981	};
661		982
662	limit $statgrp $maxreq;	983	limit $statgrp $maxreq;
663	feed $statgrp sub {	984	feed $statgrp sub {
664	return unless @$entries;	985	return unless @$entries;
665	my $entry = pop @$entries;	986	my $entry = shift @$entries;
666		987
667	aioreq_pri $pri;	988	aioreq_pri $pri;
668	add $statgrp aio_stat "$path/$entry/.", sub {	989	add $statgrp aio_stat "$path/$entry/.", sub {
669	if ($_[0] < 0) {	990	if ($_[0] < 0) {
670	push @nondirs, $entry;	991	push @nondirs, $entry;
671	} else {	992	} else {
672	# need to check for real directory	993	# need to check for real directory
673	aioreq_pri $pri;	994	aioreq_pri $pri;
674	add $statgrp aio_lstat "$path/$entry", sub {	995	add $statgrp aio_lstat "$path/$entry", sub {
675	if (-d _) {	996	if (-d _) {
676	push @dirs, $entry;	997	push @dirs, $entry;
677		998
678	unless (--$ndirs) {	999	unless (--$ndirs) {
679	push @nondirs, @$entries;	1000	push @nondirs, @$entries;
680	feed $statgrp;	1001	feed $statgrp;
681	}
682	} else {
683	push @nondirs, $entry;
684	}	1002	}
		1003	} else {
		1004	push @nondirs, $entry;
685	}	1005	}
686	}	1006	}
687	};	1007	}
688	};	1008	};
689	};	1009	};
690	};	1010	};
691	};	1011	};
692
693	$grp
694	}	1012	};
		1013
		1014	$grp
695	}	1015	}
		1016
		1017	=item aio_rmtree $path, $callback->($status)
		1018
		1019	Delete a directory tree starting (and including) C<$path>, return the
		1020	status of the final C<rmdir> only. This is a composite request that
		1021	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		1022	everything else.
		1023
		1024	=cut
		1025
		1026	sub aio_rmtree;
		1027	sub aio_rmtree($;$) {
		1028	my ($path, $cb) = @_;
		1029
		1030	my $pri = aioreq_pri;
		1031	my $grp = aio_group $cb;
		1032
		1033	aioreq_pri $pri;
		1034	add $grp aio_scandir $path, 0, sub {
		1035	my ($dirs, $nondirs) = @_;
		1036
		1037	my $dirgrp = aio_group sub {
		1038	add $grp aio_rmdir $path, sub {
		1039	$grp->result ($_[0]);
		1040	};
		1041	};
		1042
		1043	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1044	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1045
		1046	add $grp $dirgrp;
		1047	};
		1048
		1049	$grp
		1050	}
		1051
		1052	=item aio_sync $callback->($status)
		1053
		1054	Asynchronously call sync and call the callback when finished.
696		1055
697	=item aio_fsync $fh, $callback->($status)	1056	=item aio_fsync $fh, $callback->($status)
698		1057
699	Asynchronously call fsync on the given filehandle and call the callback	1058	Asynchronously call fsync on the given filehandle and call the callback
700	with the fsync result code.	1059	with the fsync result code.
…		…
704	Asynchronously call fdatasync on the given filehandle and call the	1063	Asynchronously call fdatasync on the given filehandle and call the
705	callback with the fdatasync result code.	1064	callback with the fdatasync result code.
706		1065
707	If this call isn't available because your OS lacks it or it couldn't be	1066	If this call isn't available because your OS lacks it or it couldn't be
708	detected, it will be emulated by calling C<fsync> instead.	1067	detected, it will be emulated by calling C<fsync> instead.
		1068
		1069	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1070
		1071	Sync the data portion of the file specified by C<$offset> and C<$length>
		1072	to disk (but NOT the metadata), by calling the Linux-specific
		1073	sync_file_range call. If sync_file_range is not available or it returns
		1074	ENOSYS, then fdatasync or fsync is being substituted.
		1075
		1076	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1077	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1078	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1079	manpage for details.
		1080
		1081	=item aio_pathsync $path, $callback->($status)
		1082
		1083	This request tries to open, fsync and close the given path. This is a
		1084	composite request intended to sync directories after directory operations
		1085	(E.g. rename). This might not work on all operating systems or have any
		1086	specific effect, but usually it makes sure that directory changes get
		1087	written to disc. It works for anything that can be opened for read-only,
		1088	not just directories.
		1089
		1090	Future versions of this function might fall back to other methods when
		1091	C<fsync> on the directory fails (such as calling C<sync>).
		1092
		1093	Passes C<0> when everything went ok, and C<-1> on error.
		1094
		1095	=cut
		1096
		1097	sub aio_pathsync($;$) {
		1098	my ($path, $cb) = @_;
		1099
		1100	my $pri = aioreq_pri;
		1101	my $grp = aio_group $cb;
		1102
		1103	aioreq_pri $pri;
		1104	add $grp aio_open $path, O_RDONLY, 0, sub {
		1105	my ($fh) = @_;
		1106	if ($fh) {
		1107	aioreq_pri $pri;
		1108	add $grp aio_fsync $fh, sub {
		1109	$grp->result ($_[0]);
		1110
		1111	aioreq_pri $pri;
		1112	add $grp aio_close $fh;
		1113	};
		1114	} else {
		1115	$grp->result (-1);
		1116	}
		1117	};
		1118
		1119	$grp
		1120	}
		1121
		1122	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1123
		1124	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1125	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1126	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1127	scalar must only be modified in-place while an aio operation is pending on
		1128	it).
		1129
		1130	It calls the C<msync> function of your OS, if available, with the memory
		1131	area starting at C<$offset> in the string and ending C<$length> bytes
		1132	later. If C<$length> is negative, counts from the end, and if C<$length>
		1133	is C<undef>, then it goes till the end of the string. The flags can be
		1134	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1135	C<IO::AIO::MS_SYNC>.
		1136
		1137	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1138
		1139	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1140	scalars.
		1141
		1142	It touches (reads or writes) all memory pages in the specified
		1143	range inside the scalar. All caveats and parameters are the same
		1144	as for C<aio_msync>, above, except for flags, which must be either
		1145	C<0> (which reads all pages and ensures they are instantiated) or
		1146	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1147	writing an octet from it, which dirties the page).
		1148
		1149	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1150
		1151	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1152	scalars.
		1153
		1154	It reads in all the pages of the underlying storage into memory (if any)
		1155	and locks them, so they are not getting swapped/paged out or removed.
		1156
		1157	If C<$length> is undefined, then the scalar will be locked till the end.
		1158
		1159	On systems that do not implement C<mlock>, this function returns C<-1>
		1160	and sets errno to C<ENOSYS>.
		1161
		1162	Note that the corresponding C<munlock> is synchronous and is
		1163	documented under L<MISCELLANEOUS FUNCTIONS>.
		1164
		1165	Example: open a file, mmap and mlock it - both will be undone when
		1166	C<$data> gets destroyed.
		1167
		1168	open my $fh, "<", $path or die "$path: $!";
		1169	my $data;
		1170	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1171	aio_mlock $data; # mlock in background
		1172
		1173	=item aio_mlockall $flags, $callback->($status)
		1174
		1175	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1176	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1177
		1178	On systems that do not implement C<mlockall>, this function returns C<-1>
		1179	and sets errno to C<ENOSYS>.
		1180
		1181	Note that the corresponding C<munlockall> is synchronous and is
		1182	documented under L<MISCELLANEOUS FUNCTIONS>.
		1183
		1184	Example: asynchronously lock all current and future pages into memory.
		1185
		1186	aio_mlockall IO::AIO::MCL_FUTURE;
709		1187
710	=item aio_group $callback->(...)	1188	=item aio_group $callback->(...)
711		1189
712	This is a very special aio request: Instead of doing something, it is a	1190	This is a very special aio request: Instead of doing something, it is a
713	container for other aio requests, which is useful if you want to bundle	1191	container for other aio requests, which is useful if you want to bundle
…		…
763	=item cancel $req	1241	=item cancel $req
764		1242
765	Cancels the request, if possible. Has the effect of skipping execution	1243	Cancels the request, if possible. Has the effect of skipping execution
766	when entering the B<execute> state and skipping calling the callback when	1244	when entering the B<execute> state and skipping calling the callback when
767	entering the the B<result> state, but will leave the request otherwise	1245	entering the the B<result> state, but will leave the request otherwise
768	untouched. That means that requests that currently execute will not be	1246	untouched (with the exception of readdir). That means that requests that
769	stopped and resources held by the request will not be freed prematurely.	1247	currently execute will not be stopped and resources held by the request
		1248	will not be freed prematurely.
770		1249
771	=item cb $req $callback->(...)	1250	=item cb $req $callback->(...)
772		1251
773	Replace (or simply set) the callback registered to the request.	1252	Replace (or simply set) the callback registered to the request.
774		1253
…		…
825	Their lifetime, simplified, looks like this: when they are empty, they	1304	Their lifetime, simplified, looks like this: when they are empty, they
826	will finish very quickly. If they contain only requests that are in the	1305	will finish very quickly. If they contain only requests that are in the
827	C<done> state, they will also finish. Otherwise they will continue to	1306	C<done> state, they will also finish. Otherwise they will continue to
828	exist.	1307	exist.
829		1308
830	That means after creating a group you have some time to add requests. And	1309	That means after creating a group you have some time to add requests
831	in the callbacks of those requests, you can add further requests to the	1310	(precisely before the callback has been invoked, which is only done within
832	group. And only when all those requests have finished will the the group	1311	the C<poll_cb>). And in the callbacks of those requests, you can add
833	itself finish.	1312	further requests to the group. And only when all those requests have
		1313	finished will the the group itself finish.
834		1314
835	=over 4	1315	=over 4
836		1316
837	=item add $grp ...	1317	=item add $grp ...
838		1318
…		…
847	=item $grp->cancel_subs	1327	=item $grp->cancel_subs
848		1328
849	Cancel all subrequests and clears any feeder, but not the group request	1329	Cancel all subrequests and clears any feeder, but not the group request
850	itself. Useful when you queued a lot of events but got a result early.	1330	itself. Useful when you queued a lot of events but got a result early.
851		1331
		1332	The group request will finish normally (you cannot add requests to the
		1333	group).
		1334
852	=item $grp->result (...)	1335	=item $grp->result (...)
853		1336
854	Set the result value(s) that will be passed to the group callback when all	1337	Set the result value(s) that will be passed to the group callback when all
855	subrequests have finished and set thre groups errno to the current value	1338	subrequests have finished and set the groups errno to the current value
856	of errno (just like calling C<errno> without an error number). By default,	1339	of errno (just like calling C<errno> without an error number). By default,
857	no argument will be passed and errno is zero.	1340	no argument will be passed and errno is zero.
858		1341
859	=item $grp->errno ([$errno])	1342	=item $grp->errno ([$errno])
860		1343
…		…
871	=item feed $grp $callback->($grp)	1354	=item feed $grp $callback->($grp)
872		1355
873	Sets a feeder/generator on this group: every group can have an attached	1356	Sets a feeder/generator on this group: every group can have an attached
874	generator that generates requests if idle. The idea behind this is that,	1357	generator that generates requests if idle. The idea behind this is that,
875	although you could just queue as many requests as you want in a group,	1358	although you could just queue as many requests as you want in a group,
876	this might starve other requests for a potentially long time. For	1359	this might starve other requests for a potentially long time. For example,
877	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1360	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
878	requests, delaying any later requests for a long time.	1361	delaying any later requests for a long time.
879		1362
880	To avoid this, and allow incremental generation of requests, you can	1363	To avoid this, and allow incremental generation of requests, you can
881	instead a group and set a feeder on it that generates those requests. The	1364	instead a group and set a feeder on it that generates those requests. The
882	feed callback will be called whenever there are few enough (see C<limit>,	1365	feed callback will be called whenever there are few enough (see C<limit>,
883	below) requests active in the group itself and is expected to queue more	1366	below) requests active in the group itself and is expected to queue more
…		…
887	not impose any limits).	1370	not impose any limits).
888		1371
889	If the feed does not queue more requests when called, it will be	1372	If the feed does not queue more requests when called, it will be
890	automatically removed from the group.	1373	automatically removed from the group.
891		1374
892	If the feed limit is C<0>, it will be set to C<2> automatically.	1375	If the feed limit is C<0> when this method is called, it will be set to
		1376	C<2> automatically.
893		1377
894	Example:	1378	Example:
895		1379
896	# stat all files in @files, but only ever use four aio requests concurrently:	1380	# stat all files in @files, but only ever use four aio requests concurrently:
897		1381
…		…
909	Sets the feeder limit for the group: The feeder will be called whenever	1393	Sets the feeder limit for the group: The feeder will be called whenever
910	the group contains less than this many requests.	1394	the group contains less than this many requests.
911		1395
912	Setting the limit to C<0> will pause the feeding process.	1396	Setting the limit to C<0> will pause the feeding process.
913		1397
		1398	The default value for the limit is C<0>, but note that setting a feeder
		1399	automatically bumps it up to C<2>.
		1400
914	=back	1401	=back
915		1402
916	=head2 SUPPORT FUNCTIONS	1403	=head2 SUPPORT FUNCTIONS
917		1404
918	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1405	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
920	=over 4	1407	=over 4
921		1408
922	=item $fileno = IO::AIO::poll_fileno	1409	=item $fileno = IO::AIO::poll_fileno
923		1410
924	Return the I<request result pipe file descriptor>. This filehandle must be	1411	Return the I<request result pipe file descriptor>. This filehandle must be
925	polled for reading by some mechanism outside this module (e.g. Event or	1412	polled for reading by some mechanism outside this module (e.g. EV, Glib,
926	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1413	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
927	to call C<poll_cb> to check the results.	1414	you have to call C<poll_cb> to check the results.
928		1415
929	See C<poll_cb> for an example.	1416	See C<poll_cb> for an example.
930		1417
931	=item IO::AIO::poll_cb	1418	=item IO::AIO::poll_cb
932		1419
933	Process some outstanding events on the result pipe. You have to call this	1420	Process some outstanding events on the result pipe. You have to call
934	regularly. Returns the number of events processed. Returns immediately	1421	this regularly. Returns C<0> if all events could be processed (or there
935	when no events are outstanding. The amount of events processed depends on	1422	were no events to process), or C<-1> if it returned earlier for whatever
936	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1423	reason. Returns immediately when no events are outstanding. The amount of
		1424	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1425	C<IO::AIO::max_poll_time>.
937		1426
938	If not all requests were processed for whatever reason, the filehandle	1427	If not all requests were processed for whatever reason, the filehandle
939	will still be ready when C<poll_cb> returns.	1428	will still be ready when C<poll_cb> returns, so normally you don't have to
		1429	do anything special to have it called later.
		1430
		1431	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1432	ready, it can be beneficial to call this function from loops which submit
		1433	a lot of requests, to make sure the results get processed when they become
		1434	available and not just when the loop is finished and the event loop takes
		1435	over again. This function returns very fast when there are no outstanding
		1436	requests.
940		1437
941	Example: Install an Event watcher that automatically calls	1438	Example: Install an Event watcher that automatically calls
942	IO::AIO::poll_cb with high priority:	1439	IO::AIO::poll_cb with high priority (more examples can be found in the
		1440	SYNOPSIS section, at the top of this document):
943		1441
944	Event->io (fd => IO::AIO::poll_fileno,	1442	Event->io (fd => IO::AIO::poll_fileno,
945	poll => 'r', async => 1,	1443	poll => 'r', async => 1,
946	cb => \&IO::AIO::poll_cb);	1444	cb => \&IO::AIO::poll_cb);
		1445
		1446	=item IO::AIO::poll_wait
		1447
		1448	If there are any outstanding requests and none of them in the result
		1449	phase, wait till the result filehandle becomes ready for reading (simply
		1450	does a C<select> on the filehandle. This is useful if you want to
		1451	synchronously wait for some requests to finish).
		1452
		1453	See C<nreqs> for an example.
		1454
		1455	=item IO::AIO::poll
		1456
		1457	Waits until some requests have been handled.
		1458
		1459	Returns the number of requests processed, but is otherwise strictly
		1460	equivalent to:
		1461
		1462	IO::AIO::poll_wait, IO::AIO::poll_cb
		1463
		1464	=item IO::AIO::flush
		1465
		1466	Wait till all outstanding AIO requests have been handled.
		1467
		1468	Strictly equivalent to:
		1469
		1470	IO::AIO::poll_wait, IO::AIO::poll_cb
		1471	while IO::AIO::nreqs;
947		1472
948	=item IO::AIO::max_poll_reqs $nreqs	1473	=item IO::AIO::max_poll_reqs $nreqs
949		1474
950	=item IO::AIO::max_poll_time $seconds	1475	=item IO::AIO::max_poll_time $seconds
951		1476
…		…
976	# use a low priority so other tasks have priority	1501	# use a low priority so other tasks have priority
977	Event->io (fd => IO::AIO::poll_fileno,	1502	Event->io (fd => IO::AIO::poll_fileno,
978	poll => 'r', nice => 1,	1503	poll => 'r', nice => 1,
979	cb => &IO::AIO::poll_cb);	1504	cb => &IO::AIO::poll_cb);
980		1505
981	=item IO::AIO::poll_wait	1506	=back
982
983	If there are any outstanding requests and none of them in the result
984	phase, wait till the result filehandle becomes ready for reading (simply
985	does a C<select> on the filehandle. This is useful if you want to
986	synchronously wait for some requests to finish).
987
988	See C<nreqs> for an example.
989
990	=item IO::AIO::poll
991
992	Waits until some requests have been handled.
993
994	Returns the number of requests processed, but is otherwise strictly
995	equivalent to:
996
997	IO::AIO::poll_wait, IO::AIO::poll_cb
998
999	=item IO::AIO::flush
1000
1001	Wait till all outstanding AIO requests have been handled.
1002
1003	Strictly equivalent to:
1004
1005	IO::AIO::poll_wait, IO::AIO::poll_cb
1006	while IO::AIO::nreqs;
1007		1507
1008	=head3 CONTROLLING THE NUMBER OF THREADS	1508	=head3 CONTROLLING THE NUMBER OF THREADS
		1509
		1510	=over
1009		1511
1010	=item IO::AIO::min_parallel $nthreads	1512	=item IO::AIO::min_parallel $nthreads
1011		1513
1012	Set the minimum number of AIO threads to C<$nthreads>. The current	1514	Set the minimum number of AIO threads to C<$nthreads>. The current
1013	default is C<8>, which means eight asynchronous operations can execute	1515	default is C<8>, which means eight asynchronous operations can execute
…		…
1041		1543
1042	Under normal circumstances you don't need to call this function.	1544	Under normal circumstances you don't need to call this function.
1043		1545
1044	=item IO::AIO::max_idle $nthreads	1546	=item IO::AIO::max_idle $nthreads
1045		1547
1046	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1548	Limit the number of threads (default: 4) that are allowed to idle
1047	threads that did not get a request to process within 10 seconds). That	1549	(i.e., threads that did not get a request to process within the idle
1048	means if a thread becomes idle while C<$nthreads> other threads are also	1550	timeout (default: 10 seconds). That means if a thread becomes idle while
1049	idle, it will free its resources and exit.	1551	C<$nthreads> other threads are also idle, it will free its resources and
		1552	exit.
1050		1553
1051	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1554	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1052	to allow for extremely high load situations, but want to free resources	1555	to allow for extremely high load situations, but want to free resources
1053	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1556	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1054		1557
1055	The default is probably ok in most situations, especially if thread	1558	The default is probably ok in most situations, especially if thread
1056	creation is fast. If thread creation is very slow on your system you might	1559	creation is fast. If thread creation is very slow on your system you might
1057	want to use larger values.	1560	want to use larger values.
1058		1561
		1562	=item IO::AIO::idle_timeout $seconds
		1563
		1564	Sets the minimum idle timeout (default 10) after which worker threads are
		1565	allowed to exit. SEe C<IO::AIO::max_idle>.
		1566
1059	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1567	=item IO::AIO::max_outstanding $maxreqs
		1568
		1569	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1570	you do queue up more than this number of requests, the next call to
		1571	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1572	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1573	longer exceeded.
		1574
		1575	In other words, this setting does not enforce a queue limit, but can be
		1576	used to make poll functions block if the limit is exceeded.
1060		1577
1061	This is a very bad function to use in interactive programs because it	1578	This is a very bad function to use in interactive programs because it
1062	blocks, and a bad way to reduce concurrency because it is inexact: Better	1579	blocks, and a bad way to reduce concurrency because it is inexact: Better
1063	use an C<aio_group> together with a feed callback.	1580	use an C<aio_group> together with a feed callback.
1064		1581
1065	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1582	It's main use is in scripts without an event loop - when you want to stat
1066	to queue up more than this number of requests, the next call to the	1583	a lot of files, you can write somehting like this:
1067	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1068	function will block until the limit is no longer exceeded.
1069		1584
1070	The default value is very large, so there is no practical limit on the	1585	IO::AIO::max_outstanding 32;
1071	number of outstanding requests.
1072		1586
1073	You can still queue as many requests as you want. Therefore,	1587	for my $path (...) {
1074	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1588	aio_stat $path , ...;
1075	as a stop gap to shield against fatal memory overflow (with large values).	1589	IO::AIO::poll_cb;
		1590	}
		1591
		1592	IO::AIO::flush;
		1593
		1594	The call to C<poll_cb> inside the loop will normally return instantly, but
		1595	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1596	some requests have been handled. This keeps the loop from pushing a large
		1597	number of C<aio_stat> requests onto the queue.
		1598
		1599	The default value for C<max_outstanding> is very large, so there is no
		1600	practical limit on the number of outstanding requests.
		1601
		1602	=back
1076		1603
1077	=head3 STATISTICAL INFORMATION	1604	=head3 STATISTICAL INFORMATION
		1605
		1606	=over
1078		1607
1079	=item IO::AIO::nreqs	1608	=item IO::AIO::nreqs
1080		1609
1081	Returns the number of requests currently in the ready, execute or pending	1610	Returns the number of requests currently in the ready, execute or pending
1082	states (i.e. for which their callback has not been invoked yet).	1611	states (i.e. for which their callback has not been invoked yet).
…		…
1096	Returns the number of requests currently in the pending state (executed,	1625	Returns the number of requests currently in the pending state (executed,
1097	but not yet processed by poll_cb).	1626	but not yet processed by poll_cb).
1098		1627
1099	=back	1628	=back
1100		1629
		1630	=head3 MISCELLANEOUS FUNCTIONS
		1631
		1632	IO::AIO implements some functions that might be useful, but are not
		1633	asynchronous.
		1634
		1635	=over 4
		1636
		1637	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1638
		1639	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1640	but is blocking (this makes most sense if you know the input data is
		1641	likely cached already and the output filehandle is set to non-blocking
		1642	operations).
		1643
		1644	Returns the number of bytes copied, or C<-1> on error.
		1645
		1646	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1647
		1648	Simply calls the C<posix_fadvise> function (see its
		1649	manpage for details). The following advice constants are
		1650	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1651	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1652	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1653
		1654	On systems that do not implement C<posix_fadvise>, this function returns
		1655	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1656
		1657	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1658
		1659	Simply calls the C<posix_madvise> function (see its
		1660	manpage for details). The following advice constants are
		1661	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1662	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1663
		1664	On systems that do not implement C<posix_madvise>, this function returns
		1665	ENOSYS, otherwise the return value of C<posix_madvise>.
		1666
		1667	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1668
		1669	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1670	$scalar (see its manpage for details). The following protect
		1671	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1672	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1673
		1674	On systems that do not implement C<mprotect>, this function returns
		1675	ENOSYS, otherwise the return value of C<mprotect>.
		1676
		1677	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1678
		1679	Memory-maps a file (or anonymous memory range) and attaches it to the
		1680	given C<$scalar>, which will act like a string scalar.
		1681
		1682	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1683	change the string length, and most read-only operations such as copying it
		1684	or searching it with regexes and so on.
		1685
		1686	Anything else is unsafe and will, at best, result in memory leaks.
		1687
		1688	The memory map associated with the C<$scalar> is automatically removed
		1689	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1690	C<IO::AIO::munmap> functions are called.
		1691
		1692	This calls the C<mmap>(2) function internally. See your system's manual
		1693	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1694
		1695	The C<$length> must be larger than zero and smaller than the actual
		1696	filesize.
		1697
		1698	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1699	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1700
		1701	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1702	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1703	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1704	(which is set to C<MAP_ANON> if your system only provides this
		1705	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1706	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1707	C<IO::AIO::MAP_NONBLOCK>
		1708
		1709	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1710
		1711	C<$offset> is the offset from the start of the file - it generally must be
		1712	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1713
		1714	Example:
		1715
		1716	use Digest::MD5;
		1717	use IO::AIO;
		1718
		1719	open my $fh, "<verybigfile"
		1720	or die "$!";
		1721
		1722	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1723	or die "verybigfile: $!";
		1724
		1725	my $fast_md5 = md5 $data;
		1726
		1727	=item IO::AIO::munmap $scalar
		1728
		1729	Removes a previous mmap and undefines the C<$scalar>.
		1730
		1731	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1732
		1733	Calls the C<munlock> function, undoing the effects of a previous
		1734	C<aio_mlock> call (see its description for details).
		1735
		1736	=item IO::AIO::munlockall
		1737
		1738	Calls the C<munlockall> function.
		1739
		1740	On systems that do not implement C<munlockall>, this function returns
		1741	ENOSYS, otherwise the return value of C<munlockall>.
		1742
		1743	=back
		1744
1101	=cut	1745	=cut
1102		1746
1103	# support function to convert a fd into a perl filehandle
1104	sub _fd2fh {
1105	return undef if $_[0] < 0;
1106
1107	# try to generate nice filehandles
1108	my $sym = "IO::AIO::fd#$_[0]";
1109	local *$sym;
1110
1111	open *$sym, "+<&=$_[0]" # usually works under any unix
1112	or open *$sym, "<&=$_[0]" # cygwin needs this
1113	or open *$sym, ">&=$_[0]" # or this
1114	or return undef;
1115
1116	*$sym
1117	}
1118
1119	min_parallel 8;	1747	min_parallel 8;
1120		1748
1121	END { flush }	1749	END { flush }
1122		1750
1123	1;	1751	1;
		1752
		1753	=head1 EVENT LOOP INTEGRATION
		1754
		1755	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1756	automatically into many event loops:
		1757
		1758	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1759	use AnyEvent::AIO;
		1760
		1761	You can also integrate IO::AIO manually into many event loops, here are
		1762	some examples of how to do this:
		1763
		1764	# EV integration
		1765	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1766
		1767	# Event integration
		1768	Event->io (fd => IO::AIO::poll_fileno,
		1769	poll => 'r',
		1770	cb => \&IO::AIO::poll_cb);
		1771
		1772	# Glib/Gtk2 integration
		1773	add_watch Glib::IO IO::AIO::poll_fileno,
		1774	in => sub { IO::AIO::poll_cb; 1 };
		1775
		1776	# Tk integration
		1777	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1778	readable => \&IO::AIO::poll_cb);
		1779
		1780	# Danga::Socket integration
		1781	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1782	\&IO::AIO::poll_cb);
1124		1783
1125	=head2 FORK BEHAVIOUR	1784	=head2 FORK BEHAVIOUR
1126		1785
1127	This module should do "the right thing" when the process using it forks:	1786	This module should do "the right thing" when the process using it forks:
1128		1787
…		…
1146	bytes of memory. In addition, stat requests need a stat buffer (possibly	1805	bytes of memory. In addition, stat requests need a stat buffer (possibly
1147	a few hundred bytes), readdir requires a result buffer and so on. Perl	1806	a few hundred bytes), readdir requires a result buffer and so on. Perl
1148	scalars and other data passed into aio requests will also be locked and	1807	scalars and other data passed into aio requests will also be locked and
1149	will consume memory till the request has entered the done state.	1808	will consume memory till the request has entered the done state.
1150		1809
1151	This is now awfully much, so queuing lots of requests is not usually a	1810	This is not awfully much, so queuing lots of requests is not usually a
1152	problem.	1811	problem.
1153		1812
1154	Per-thread usage:	1813	Per-thread usage:
1155		1814
1156	In the execution phase, some aio requests require more memory for	1815	In the execution phase, some aio requests require more memory for
…		…
1161		1820
1162	Known bugs will be fixed in the next release.	1821	Known bugs will be fixed in the next release.
1163		1822
1164	=head1 SEE ALSO	1823	=head1 SEE ALSO
1165		1824
1166	L<Coro::AIO>.	1825	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1826	more natural syntax.
1167		1827
1168	=head1 AUTHOR	1828	=head1 AUTHOR
1169		1829
1170	Marc Lehmann <schmorp@schmorp.de>	1830	Marc Lehmann <schmorp@schmorp.de>
1171	http://home.schmorp.de/	1831	http://home.schmorp.de/

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines