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Revision 1.105 by root, Sun Mar 25 00:20:27 2007 UTC vs.
Revision 1.207 by root, Mon Jul 25 16:50:33 2011 UTC

…		…
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10	my $fh = shift	10	my $fh = shift
11	or die "/etc/passwd: $!";	11	or die "/etc/passwd: $!";
12	...	12	...
13	};	13	};
14		14
…		…
26	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
27		27
28	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
29	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
30		30
31	# AnyEvent integration
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',
38	cb => \&IO::AIO::poll_cb);
39
40	# Glib/Gtk2 integration
41	add_watch Glib::IO IO::AIO::poll_fileno,
42	in => sub { IO::AIO::poll_cb; 1 };
43
44	# Tk integration
45	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46	readable => \&IO::AIO::poll_cb);
47
48	# Danga::Socket integration
49	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50	\&IO::AIO::poll_cb);
51
52	=head1 DESCRIPTION	31	=head1 DESCRIPTION
53		32
54	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
55	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
56		36
57	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
58	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
59	will still block, but you can do something else in the meantime. This	39	will still block, but you can do something else in the meantime. This
60	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
62	etc.), but can also be used to easily do operations in parallel that are	42	etc.), but can also be used to easily do operations in parallel that are
63	normally done sequentially, e.g. stat'ing many files, which is much faster	43	normally done sequentially, e.g. stat'ing many files, which is much faster
64	on a RAID volume or over NFS when you do a number of stat operations	44	on a RAID volume or over NFS when you do a number of stat operations
65	concurrently.	45	concurrently.
66		46
67	While most of this works on all types of file descriptors (for example	47	While most of this works on all types of file descriptors (for
68	sockets), using these functions on file descriptors that support	48	example sockets), using these functions on file descriptors that
69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or	49	support nonblocking operation (again, sockets, pipes etc.) is
70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop	50	very inefficient. Use an event loop for that (such as the L<EV>
71	for that (such as the L<Event|Event> module): IO::AIO will naturally fit	51	module): IO::AIO will naturally fit into such an event loop itself.
72	into such an event loop itself.
73		52
74	In this version, a number of threads are started that execute your	53	In this version, a number of threads are started that execute your
75	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
76	in perl, and the threads created by this module will not be visible	55	in perl, and the threads created by this module will not be visible
77	to perl. In the future, this module might make use of the native aio	56	to perl. In the future, this module might make use of the native aio
…		…
79	not well-supported or restricted (GNU/Linux doesn't allow them on normal	58	not well-supported or restricted (GNU/Linux doesn't allow them on normal
80	files currently, for example), and they would only support aio_read and	59	files currently, for example), and they would only support aio_read and
81	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
82	using threads anyway.	61	using threads anyway.
83		62
84	Although the module will work with in the presence of other (Perl-)	63	Although the module will work in the presence of other (Perl-) threads,
85	threads, it is currently not reentrant in any way, so use appropriate	64	it is currently not reentrant in any way, so use appropriate locking
86	locking yourself, always call C<poll_cb> from within the same thread, or	65	yourself, always call C<poll_cb> from within the same thread, or never
87	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
88		67
89	=head2 EXAMPLE	68	=head2 EXAMPLE
90		69
91	This is a simple example that uses the Event module and loads	70	This is a simple example that uses the EV module and loads
92	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
93		72
94	use Fcntl;	73	use Fcntl;
95	use Event;	74	use EV;
96	use IO::AIO;	75	use IO::AIO;
97		76
98	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
99	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
100	poll => 'r',
101	cb => \&IO::AIO::poll_cb);
102		79
103	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105	my $fh = shift	82	my $fh = shift
106	or die "error while opening: $!";	83	or die "error while opening: $!";
107		84
108	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
109	my $size = -s $fh;	86	my $size = -s $fh;
…		…
118		95
119	# file contents now in $contents	96	# file contents now in $contents
120	print $contents;	97	print $contents;
121		98
122	# exit event loop and program	99	# exit event loop and program
123	Event::unloop;	100	EV::unloop;
124	};	101	};
125	};	102	};
126		103
127	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
128	# check for sockets etc. etc.	105	# check for sockets etc. etc.
129		106
130	# process events as long as there are some:	107	# process events as long as there are some:
131	Event::loop;	108	EV::loop;
132		109
133	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
134		111
135	Every C<aio_*> function creates a request. which is a C data structure not	112	Every C<aio_*> function creates a request. which is a C data structure not
136	directly visible to Perl.	113	directly visible to Perl.
…		…
184		161
185	=cut	162	=cut
186		163
187	package IO::AIO;	164	package IO::AIO;
188		165
189	no warnings;	166	use Carp ();
190	use strict 'vars';	167
		168	use common::sense;
191		169
192	use base 'Exporter';	170	use base 'Exporter';
193		171
194	BEGIN {	172	BEGIN {
195	our $VERSION = '2.33';	173	our $VERSION = '4.0';
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_realpath aio_sync
		178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
		179	aio_pathsync aio_readahead
		180	aio_rename aio_link aio_move aio_copy aio_group
200	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir);	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		182	aio_chmod aio_utime aio_truncate
		183	aio_msync aio_mtouch aio_mlock aio_mlockall
		184	aio_statvfs);
		185
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	188	min_parallel max_parallel max_idle idle_timeout
204	nreqs nready npending nthreads	189	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	190	max_poll_time max_poll_reqs
		191	sendfile fadvise madvise
		192	mmap munmap munlock munlockall);
		193
		194	push @AIO_REQ, qw(aio_busy); # not exported
206		195
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	196	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		197
209	require XSLoader;	198	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	199	XSLoader::load ("IO::AIO", $VERSION);
211	}	200	}
212		201
213	=head1 FUNCTIONS	202	=head1 FUNCTIONS
		203
		204	=head2 QUICK OVERVIEW
		205
		206	This section simply lists the prototypes of the most important functions
		207	for quick reference. See the following sections for function-by-function
		208	documentation.
		209
		210	aio_open $pathname, $flags, $mode, $callback->($fh)
		211	aio_close $fh, $callback->($status)
		212	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		213	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		214	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		215	aio_readahead $fh,$offset,$length, $callback->($retval)
		216	aio_stat $fh_or_path, $callback->($status)
		217	aio_lstat $fh, $callback->($status)
		218	aio_statvfs $fh_or_path, $callback->($statvfs)
		219	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		220	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		221	aio_truncate $fh_or_path, $offset, $callback->($status)
		222	aio_chmod $fh_or_path, $mode, $callback->($status)
		223	aio_unlink $pathname, $callback->($status)
		224	aio_mknod $path, $mode, $dev, $callback->($status)
		225	aio_link $srcpath, $dstpath, $callback->($status)
		226	aio_symlink $srcpath, $dstpath, $callback->($status)
		227	aio_readlink $path, $callback->($link)
		228	aio_realpath $path, $callback->($link)
		229	aio_rename $srcpath, $dstpath, $callback->($status)
		230	aio_mkdir $pathname, $mode, $callback->($status)
		231	aio_rmdir $pathname, $callback->($status)
		232	aio_readdir $pathname, $callback->($entries)
		233	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		234	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		235	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		236	aio_load $path, $data, $callback->($status)
		237	aio_copy $srcpath, $dstpath, $callback->($status)
		238	aio_move $srcpath, $dstpath, $callback->($status)
		239	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		240	aio_rmtree $path, $callback->($status)
		241	aio_sync $callback->($status)
		242	aio_syncfs $fh, $callback->($status)
		243	aio_fsync $fh, $callback->($status)
		244	aio_fdatasync $fh, $callback->($status)
		245	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		246	aio_pathsync $path, $callback->($status)
		247	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		248	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		249	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		250	aio_mlockall $flags, $callback->($status)
		251	aio_group $callback->(...)
		252	aio_nop $callback->()
		253
		254	$prev_pri = aioreq_pri [$pri]
		255	aioreq_nice $pri_adjust
		256
		257	IO::AIO::poll_wait
		258	IO::AIO::poll_cb
		259	IO::AIO::poll
		260	IO::AIO::flush
		261	IO::AIO::max_poll_reqs $nreqs
		262	IO::AIO::max_poll_time $seconds
		263	IO::AIO::min_parallel $nthreads
		264	IO::AIO::max_parallel $nthreads
		265	IO::AIO::max_idle $nthreads
		266	IO::AIO::idle_timeout $seconds
		267	IO::AIO::max_outstanding $maxreqs
		268	IO::AIO::nreqs
		269	IO::AIO::nready
		270	IO::AIO::npending
		271
		272	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		273	IO::AIO::fadvise $fh, $offset, $len, $advice
		274	IO::AIO::madvise $scalar, $offset, $length, $advice
		275	IO::AIO::mprotect $scalar, $offset, $length, $protect
		276	IO::AIO::munlock $scalar, $offset = 0, $length = undef
		277	IO::AIO::munlockall
214		278
215	=head2 AIO REQUEST FUNCTIONS	279	=head2 AIO REQUEST FUNCTIONS
216		280
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	281	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	282	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	283	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	284	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	285	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	286	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	287	syscall has been executed asynchronously.
224		288
225	All functions expecting a filehandle keep a copy of the filehandle	289	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	290	internally until the request has finished.
227		291
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	305	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)	306	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	307	use something else to ensure your scalar has the correct contents.
244		308
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	309	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	310	handles correctly whether it is set or not.
247		311
248	=over 4	312	=over 4
249		313
250	=item $prev_pri = aioreq_pri [$pri]	314	=item $prev_pri = aioreq_pri [$pri]
251		315
…		…
271	aio_read $_[0], ..., sub {	335	aio_read $_[0], ..., sub {
272	...	336	...
273	};	337	};
274	};	338	};
275		339
		340
276	=item aioreq_nice $pri_adjust	341	=item aioreq_nice $pri_adjust
277		342
278	Similar to C<aioreq_pri>, but subtracts the given value from the current	343	Similar to C<aioreq_pri>, but subtracts the given value from the current
279	priority, so the effect is cumulative.	344	priority, so the effect is cumulative.
		345
280		346
281	=item aio_open $pathname, $flags, $mode, $callback->($fh)	347	=item aio_open $pathname, $flags, $mode, $callback->($fh)
282		348
283	Asynchronously open or create a file and call the callback with a newly	349	Asynchronously open or create a file and call the callback with a newly
284	created filehandle for the file.	350	created filehandle for the file.
…		…
296	by the umask in effect then the request is being executed, so better never	362	by the umask in effect then the request is being executed, so better never
297	change the umask.	363	change the umask.
298		364
299	Example:	365	Example:
300		366
301	aio_open "/etc/passwd", O_RDONLY, 0, sub {	367	aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
302	if ($_[0]) {	368	if ($_[0]) {
303	print "open successful, fh is $_[0]\n";	369	print "open successful, fh is $_[0]\n";
304	...	370	...
305	} else {	371	} else {
306	die "open failed: $!\n";	372	die "open failed: $!\n";
307	}	373	}
308	};	374	};
309		375
		376	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		377	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		378	following POSIX and non-POSIX constants are available (missing ones on
		379	your system are, as usual, C<0>):
		380
		381	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		382	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		383	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		384
		385
310	=item aio_close $fh, $callback->($status)	386	=item aio_close $fh, $callback->($status)
311		387
312	Asynchronously close a file and call the callback with the result	388	Asynchronously close a file and call the callback with the result
313	code. I<WARNING:> although accepted, you should not pass in a perl	389	code.
314	filehandle here, as perl will likely close the file descriptor another
315	time when the filehandle is destroyed. Normally, you can safely call perls
316	C<close> or just let filehandles go out of scope.
317		390
318	This is supposed to be a bug in the API, so that might change. It's	391	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
319	therefore best to avoid this function.	392	closing the file descriptor associated with the filehandle itself.
		393
		394	Therefore, C<aio_close> will not close the filehandle - instead it will
		395	use dup2 to overwrite the file descriptor with the write-end of a pipe
		396	(the pipe fd will be created on demand and will be cached).
		397
		398	Or in other words: the file descriptor will be closed, but it will not be
		399	free for reuse until the perl filehandle is closed.
		400
		401	=cut
320		402
321	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	403	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322		404
323	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	405	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
324		406
325	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	407	Reads or writes C<$length> bytes from or to the specified C<$fh> and
326	into the scalar given by C<data> and offset C<dataoffset> and calls the	408	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
327	callback without the actual number of bytes read (or -1 on error, just	409	and calls the callback without the actual number of bytes read (or -1 on
328	like the syscall).	410	error, just like the syscall).
		411
		412	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		413	offset plus the actual number of bytes read.
		414
		415	If C<$offset> is undefined, then the current file descriptor offset will
		416	be used (and updated), otherwise the file descriptor offset will not be
		417	changed by these calls.
		418
		419	If C<$length> is undefined in C<aio_write>, use the remaining length of
		420	C<$data>.
		421
		422	If C<$dataoffset> is less than zero, it will be counted from the end of
		423	C<$data>.
329		424
330	The C<$data> scalar I<MUST NOT> be modified in any way while the request	425	The C<$data> scalar I<MUST NOT> be modified in any way while the request
331	is outstanding. Modifying it can result in segfaults or WW3 (if the	426	is outstanding. Modifying it can result in segfaults or World War III (if
332	necessary/optional hardware is installed).	427	the necessary/optional hardware is installed).
333		428
334	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	429	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
335	offset C<0> within the scalar:	430	offset C<0> within the scalar:
336		431
337	aio_read $fh, 7, 15, $buffer, 0, sub {	432	aio_read $fh, 7, 15, $buffer, 0, sub {
338	$_[0] > 0 or die "read error: $!";	433	$_[0] > 0 or die "read error: $!";
339	print "read $_[0] bytes: <$buffer>\n";	434	print "read $_[0] bytes: <$buffer>\n";
340	};	435	};
341		436
		437
342	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	438	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
343		439
344	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	440	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
345	reading at byte offset C<$in_offset>, and starts writing at the current	441	reading at byte offset C<$in_offset>, and starts writing at the current
346	file offset of C<$out_fh>. Because of that, it is not safe to issue more	442	file offset of C<$out_fh>. Because of that, it is not safe to issue more
347	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	443	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
348	other.	444	other. The same C<$in_fh> works fine though, as this function does not
		445	move or use the file offset of C<$in_fh>.
349		446
		447	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
		448	are written, and there is no way to find out how many more bytes have been
		449	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
		450	number of bytes written to C<$out_fh>. Only if the result value equals
		451	C<$length> one can assume that C<$length> bytes have been read.
		452
		453	Unlike with other C<aio_> functions, it makes a lot of sense to use
		454	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
		455	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
		456	the socket I/O will be non-blocking. Note, however, that you can run
		457	into a trap where C<aio_sendfile> reads some data with readahead, then
		458	fails to write all data, and when the socket is ready the next time, the
		459	data in the cache is already lost, forcing C<aio_sendfile> to again hit
		460	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
		461	resource usage.
		462
350	This call tries to make use of a native C<sendfile> syscall to provide	463	This call tries to make use of a native C<sendfile>-like syscall to
351	zero-copy operation. For this to work, C<$out_fh> should refer to a	464	provide zero-copy operation. For this to work, C<$out_fh> should refer to
352	socket, and C<$in_fh> should refer to mmap'able file.	465	a socket, and C<$in_fh> should refer to an mmap'able file.
353		466
354	If the native sendfile call fails or is not implemented, it will be	467	If a native sendfile cannot be found or it fails with C<ENOSYS>,
355	emulated, so you can call C<aio_sendfile> on any type of filehandle	468	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
		469	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
356	regardless of the limitations of the operating system.	470	type of filehandle regardless of the limitations of the operating system.
357		471
358	Please note, however, that C<aio_sendfile> can read more bytes from	472	As native sendfile syscalls (as practically any non-POSIX interface hacked
359	C<$in_fh> than are written, and there is no way to find out how many	473	together in a hurry to improve benchmark numbers) tend to be rather buggy
360	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	474	on many systems, this implementation tries to work around some known bugs
361	provides the number of bytes written to C<$out_fh>. Only if the result	475	in Linux and FreeBSD kernels (probably others, too), but that might fail,
362	value equals C<$length> one can assume that C<$length> bytes have been	476	so you really really should check the return value of C<aio_sendfile> -
363	read.	477	fewre bytes than expected might have been transferred.
		478
364		479
365	=item aio_readahead $fh,$offset,$length, $callback->($retval)	480	=item aio_readahead $fh,$offset,$length, $callback->($retval)
366		481
367	C<aio_readahead> populates the page cache with data from a file so that	482	C<aio_readahead> populates the page cache with data from a file so that
368	subsequent reads from that file will not block on disk I/O. The C<$offset>	483	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
374	file. The current file offset of the file is left unchanged.	489	file. The current file offset of the file is left unchanged.
375		490
376	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	491	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
377	emulated by simply reading the data, which would have a similar effect.	492	emulated by simply reading the data, which would have a similar effect.
378		493
		494
379	=item aio_stat $fh_or_path, $callback->($status)	495	=item aio_stat $fh_or_path, $callback->($status)
380		496
381	=item aio_lstat $fh, $callback->($status)	497	=item aio_lstat $fh, $callback->($status)
382		498
383	Works like perl's C<stat> or C<lstat> in void context. The callback will	499	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
388	for an explanation.	504	for an explanation.
389		505
390	Currently, the stats are always 64-bit-stats, i.e. instead of returning an	506	Currently, the stats are always 64-bit-stats, i.e. instead of returning an
391	error when stat'ing a large file, the results will be silently truncated	507	error when stat'ing a large file, the results will be silently truncated
392	unless perl itself is compiled with large file support.	508	unless perl itself is compiled with large file support.
		509
		510	To help interpret the mode and dev/rdev stat values, IO::AIO offers the
		511	following constants and functions (if not implemented, the constants will
		512	be C<0> and the functions will either C<croak> or fall back on traditional
		513	behaviour).
		514
		515	C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
		516	C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
		517	C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
393		518
394	Example: Print the length of F</etc/passwd>:	519	Example: Print the length of F</etc/passwd>:
395		520
396	aio_stat "/etc/passwd", sub {	521	aio_stat "/etc/passwd", sub {
397	$_[0] and die "stat failed: $!";	522	$_[0] and die "stat failed: $!";
398	print "size is ", -s _, "\n";	523	print "size is ", -s _, "\n";
399	};	524	};
400		525
		526
		527	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		528
		529	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		530	whether a file handle or path was passed.
		531
		532	On success, the callback is passed a hash reference with the following
		533	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		534	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		535	is passed.
		536
		537	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		538	C<ST_NOSUID>.
		539
		540	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		541	their correct value when available, or to C<0> on systems that do
		542	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		543	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		544	C<ST_NODIRATIME> and C<ST_RELATIME>.
		545
		546	Example: stat C</wd> and dump out the data if successful.
		547
		548	aio_statvfs "/wd", sub {
		549	my $f = $_[0]
		550	or die "statvfs: $!";
		551
		552	use Data::Dumper;
		553	say Dumper $f;
		554	};
		555
		556	# result:
		557	{
		558	bsize => 1024,
		559	bfree => 4333064312,
		560	blocks => 10253828096,
		561	files => 2050765568,
		562	flag => 4096,
		563	favail => 2042092649,
		564	bavail => 4333064312,
		565	ffree => 2042092649,
		566	namemax => 255,
		567	frsize => 1024,
		568	fsid => 1810
		569	}
		570
		571
		572	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		573
		574	Works like perl's C<utime> function (including the special case of $atime
		575	and $mtime being undef). Fractional times are supported if the underlying
		576	syscalls support them.
		577
		578	When called with a pathname, uses utimes(2) if available, otherwise
		579	utime(2). If called on a file descriptor, uses futimes(2) if available,
		580	otherwise returns ENOSYS, so this is not portable.
		581
		582	Examples:
		583
		584	# set atime and mtime to current time (basically touch(1)):
		585	aio_utime "path", undef, undef;
		586	# set atime to current time and mtime to beginning of the epoch:
		587	aio_utime "path", time, undef; # undef==0
		588
		589
		590	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		591
		592	Works like perl's C<chown> function, except that C<undef> for either $uid
		593	or $gid is being interpreted as "do not change" (but -1 can also be used).
		594
		595	Examples:
		596
		597	# same as "chown root path" in the shell:
		598	aio_chown "path", 0, -1;
		599	# same as above:
		600	aio_chown "path", 0, undef;
		601
		602
		603	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		604
		605	Works like truncate(2) or ftruncate(2).
		606
		607
		608	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		609
		610	Works like perl's C<chmod> function.
		611
		612
401	=item aio_unlink $pathname, $callback->($status)	613	=item aio_unlink $pathname, $callback->($status)
402		614
403	Asynchronously unlink (delete) a file and call the callback with the	615	Asynchronously unlink (delete) a file and call the callback with the
404	result code.	616	result code.
405		617
		618
406	=item aio_mknod $path, $mode, $dev, $callback->($status)	619	=item aio_mknod $path, $mode, $dev, $callback->($status)
407		620
408	[EXPERIMENTAL]	621	[EXPERIMENTAL]
409		622
410	Asynchronously create a device node (or fifo). See mknod(2).	623	Asynchronously create a device node (or fifo). See mknod(2).
411		624
412	The only (POSIX-) portable way of calling this function is:	625	The only (POSIX-) portable way of calling this function is:
413		626
414	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...	627	aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
		628
		629	See C<aio_stat> for info about some potentially helpful extra constants
		630	and functions.
415		631
416	=item aio_link $srcpath, $dstpath, $callback->($status)	632	=item aio_link $srcpath, $dstpath, $callback->($status)
417		633
418	Asynchronously create a new link to the existing object at C<$srcpath> at	634	Asynchronously create a new link to the existing object at C<$srcpath> at
419	the path C<$dstpath> and call the callback with the result code.	635	the path C<$dstpath> and call the callback with the result code.
420		636
		637
421	=item aio_symlink $srcpath, $dstpath, $callback->($status)	638	=item aio_symlink $srcpath, $dstpath, $callback->($status)
422		639
423	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	640	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
424	the path C<$dstpath> and call the callback with the result code.	641	the path C<$dstpath> and call the callback with the result code.
		642
425		643
426	=item aio_readlink $path, $callback->($link)	644	=item aio_readlink $path, $callback->($link)
427		645
428	Asynchronously read the symlink specified by C<$path> and pass it to	646	Asynchronously read the symlink specified by C<$path> and pass it to
429	the callback. If an error occurs, nothing or undef gets passed to the	647	the callback. If an error occurs, nothing or undef gets passed to the
430	callback.	648	callback.
431		649
		650
		651	=item aio_realpath $path, $callback->($path)
		652
		653	Asynchronously make the path absolute and resolve any symlinks in
		654	C<$path>. The resulting path only consists of directories (Same as
		655	L<Cwd::realpath>).
		656
		657	This request can be used to get the absolute path of the current working
		658	directory by passing it a path of F<.> (a single dot).
		659
		660
432	=item aio_rename $srcpath, $dstpath, $callback->($status)	661	=item aio_rename $srcpath, $dstpath, $callback->($status)
433		662
434	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	663	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
435	rename(2) and call the callback with the result code.	664	rename(2) and call the callback with the result code.
		665
436		666
437	=item aio_mkdir $pathname, $mode, $callback->($status)	667	=item aio_mkdir $pathname, $mode, $callback->($status)
438		668
439	Asynchronously mkdir (create) a directory and call the callback with	669	Asynchronously mkdir (create) a directory and call the callback with
440	the result code. C<$mode> will be modified by the umask at the time the	670	the result code. C<$mode> will be modified by the umask at the time the
441	request is executed, so do not change your umask.	671	request is executed, so do not change your umask.
442		672
		673
443	=item aio_rmdir $pathname, $callback->($status)	674	=item aio_rmdir $pathname, $callback->($status)
444		675
445	Asynchronously rmdir (delete) a directory and call the callback with the	676	Asynchronously rmdir (delete) a directory and call the callback with the
446	result code.	677	result code.
		678
447		679
448	=item aio_readdir $pathname, $callback->($entries)	680	=item aio_readdir $pathname, $callback->($entries)
449		681
450	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	682	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
451	directory (i.e. opendir + readdir + closedir). The entries will not be	683	directory (i.e. opendir + readdir + closedir). The entries will not be
452	sorted, and will B<NOT> include the C<.> and C<..> entries.	684	sorted, and will B<NOT> include the C<.> and C<..> entries.
453		685
454	The callback a single argument which is either C<undef> or an array-ref	686	The callback is passed a single argument which is either C<undef> or an
455	with the filenames.	687	array-ref with the filenames.
		688
		689
		690	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		691
		692	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
		693	tune behaviour and output format. In case of an error, C<$entries> will be
		694	C<undef>.
		695
		696	The flags are a combination of the following constants, ORed together (the
		697	flags will also be passed to the callback, possibly modified):
		698
		699	=over 4
		700
		701	=item IO::AIO::READDIR_DENTS
		702
		703	When this flag is off, then the callback gets an arrayref consisting of
		704	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
		705	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		706	entry in more detail.
		707
		708	C<$name> is the name of the entry.
		709
		710	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		711
		712	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		713	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		714	C<IO::AIO::DT_WHT>.
		715
		716	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		717	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		718	scalars are read-only: you can not modify them.
		719
		720	C<$inode> is the inode number (which might not be exact on systems with 64
		721	bit inode numbers and 32 bit perls). This field has unspecified content on
		722	systems that do not deliver the inode information.
		723
		724	=item IO::AIO::READDIR_DIRS_FIRST
		725
		726	When this flag is set, then the names will be returned in an order where
		727	likely directories come first, in optimal stat order. This is useful when
		728	you need to quickly find directories, or you want to find all directories
		729	while avoiding to stat() each entry.
		730
		731	If the system returns type information in readdir, then this is used
		732	to find directories directly. Otherwise, likely directories are names
		733	beginning with ".", or otherwise names with no dots, of which names with
		734	short names are tried first.
		735
		736	=item IO::AIO::READDIR_STAT_ORDER
		737
		738	When this flag is set, then the names will be returned in an order
		739	suitable for stat()'ing each one. That is, when you plan to stat()
		740	all files in the given directory, then the returned order will likely
		741	be fastest.
		742
		743	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		744	the likely dirs come first, resulting in a less optimal stat order.
		745
		746	=item IO::AIO::READDIR_FOUND_UNKNOWN
		747
		748	This flag should not be set when calling C<aio_readdirx>. Instead, it
		749	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		750	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
		751	C<$type>'s are known, which can be used to speed up some algorithms.
		752
		753	=back
		754
456		755
457	=item aio_load $path, $data, $callback->($status)	756	=item aio_load $path, $data, $callback->($status)
458		757
459	This is a composite request that tries to fully load the given file into	758	This is a composite request that tries to fully load the given file into
460	memory. Status is the same as with aio_read.	759	memory. Status is the same as with aio_read.
461		760
462	=cut	761	=cut
463		762
464	sub aio_load($$;$) {	763	sub aio_load($$;$) {
465	aio_block {
466	my ($path, undef, $cb) = @_;	764	my ($path, undef, $cb) = @_;
467	my $data = \$_[1];	765	my $data = \$_[1];
468		766
469	my $pri = aioreq_pri;	767	my $pri = aioreq_pri;
470	my $grp = aio_group $cb;	768	my $grp = aio_group $cb;
		769
		770	aioreq_pri $pri;
		771	add $grp aio_open $path, O_RDONLY, 0, sub {
		772	my $fh = shift
		773	or return $grp->result (-1);
471		774
472	aioreq_pri $pri;	775	aioreq_pri $pri;
473	add $grp aio_open $path, O_RDONLY, 0, sub {
474	my $fh = shift
475	or return $grp->result (-1);
476
477	aioreq_pri $pri;
478	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	776	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
479	$grp->result ($_[0]);	777	$grp->result ($_[0]);
480	};
481	};	778	};
482
483	$grp
484	}	779	};
		780
		781	$grp
485	}	782	}
486		783
487	=item aio_copy $srcpath, $dstpath, $callback->($status)	784	=item aio_copy $srcpath, $dstpath, $callback->($status)
488		785
489	Try to copy the I<file> (directories not supported as either source or	786	Try to copy the I<file> (directories not supported as either source or
490	destination) from C<$srcpath> to C<$dstpath> and call the callback with	787	destination) from C<$srcpath> to C<$dstpath> and call the callback with
491	the C<0> (error) or C<-1> ok.	788	a status of C<0> (ok) or C<-1> (error, see C<$!>).
492		789
493	This is a composite request that it creates the destination file with	790	This is a composite request that creates the destination file with
494	mode 0200 and copies the contents of the source file into it using	791	mode 0200 and copies the contents of the source file into it using
495	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	792	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
496	uid/gid, in that order.	793	uid/gid, in that order.
497		794
498	If an error occurs, the partial destination file will be unlinked, if	795	If an error occurs, the partial destination file will be unlinked, if
…		…
500	errors are being ignored.	797	errors are being ignored.
501		798
502	=cut	799	=cut
503		800
504	sub aio_copy($$;$) {	801	sub aio_copy($$;$) {
505	aio_block {
506	my ($src, $dst, $cb) = @_;	802	my ($src, $dst, $cb) = @_;
507		803
508	my $pri = aioreq_pri;	804	my $pri = aioreq_pri;
509	my $grp = aio_group $cb;	805	my $grp = aio_group $cb;
510		806
511	aioreq_pri $pri;	807	aioreq_pri $pri;
512	add $grp aio_open $src, O_RDONLY, 0, sub {	808	add $grp aio_open $src, O_RDONLY, 0, sub {
513	if (my $src_fh = $_[0]) {	809	if (my $src_fh = $_[0]) {
514	my @stat = stat $src_fh;	810	my @stat = stat $src_fh; # hmm, might block over nfs?
515		811
516	aioreq_pri $pri;	812	aioreq_pri $pri;
517	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {	813	add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
518	if (my $dst_fh = $_[0]) {	814	if (my $dst_fh = $_[0]) {
519	aioreq_pri $pri;	815	aioreq_pri $pri;
520	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	816	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
521	if ($_[0] == $stat[7]) {	817	if ($_[0] == $stat[7]) {
522	$grp->result (0);	818	$grp->result (0);
523	close $src_fh;	819	close $src_fh;
524		820
525	# those should not normally block. should. should.
526	utime $stat[8], $stat[9], $dst;
527	chmod $stat[2] & 07777, $dst_fh;
528	chown $stat[4], $stat[5], $dst_fh;
529	close $dst_fh;
530	} else {	821	my $ch = sub {
531	$grp->result (-1);
532	close $src_fh;
533	close $dst_fh;
534
535	aioreq $pri;	822	aioreq_pri $pri;
		823	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		824	aioreq_pri $pri;
		825	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		826	aioreq_pri $pri;
536	add $grp aio_unlink $dst;	827	add $grp aio_close $dst_fh;
		828	}
		829	};
537	}	830	};
		831
		832	aioreq_pri $pri;
		833	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		834	if ($_[0] < 0 && $! == ENOSYS) {
		835	aioreq_pri $pri;
		836	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		837	} else {
		838	$ch->();
		839	}
		840	};
		841	} else {
		842	$grp->result (-1);
		843	close $src_fh;
		844	close $dst_fh;
		845
		846	aioreq $pri;
		847	add $grp aio_unlink $dst;
538	};	848	}
539	} else {
540	$grp->result (-1);
541	}	849	};
		850	} else {
		851	$grp->result (-1);
542	},	852	}
543
544	} else {
545	$grp->result (-1);
546	}	853	},
		854
		855	} else {
		856	$grp->result (-1);
547	};	857	}
548
549	$grp
550	}	858	};
		859
		860	$grp
551	}	861	}
552		862
553	=item aio_move $srcpath, $dstpath, $callback->($status)	863	=item aio_move $srcpath, $dstpath, $callback->($status)
554		864
555	Try to move the I<file> (directories not supported as either source or	865	Try to move the I<file> (directories not supported as either source or
556	destination) from C<$srcpath> to C<$dstpath> and call the callback with	866	destination) from C<$srcpath> to C<$dstpath> and call the callback with
557	the C<0> (error) or C<-1> ok.	867	a status of C<0> (ok) or C<-1> (error, see C<$!>).
558		868
559	This is a composite request that tries to rename(2) the file first. If	869	This is a composite request that tries to rename(2) the file first; if
560	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	870	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
561	that is successful, unlinking the C<$srcpath>.	871	that is successful, unlinks the C<$srcpath>.
562		872
563	=cut	873	=cut
564		874
565	sub aio_move($$;$) {	875	sub aio_move($$;$) {
566	aio_block {
567	my ($src, $dst, $cb) = @_;	876	my ($src, $dst, $cb) = @_;
568		877
569	my $pri = aioreq_pri;	878	my $pri = aioreq_pri;
570	my $grp = aio_group $cb;	879	my $grp = aio_group $cb;
571		880
572	aioreq_pri $pri;	881	aioreq_pri $pri;
573	add $grp aio_rename $src, $dst, sub {	882	add $grp aio_rename $src, $dst, sub {
574	if ($_[0] && $! == EXDEV) {	883	if ($_[0] && $! == EXDEV) {
575	aioreq_pri $pri;	884	aioreq_pri $pri;
576	add $grp aio_copy $src, $dst, sub {	885	add $grp aio_copy $src, $dst, sub {
577	$grp->result ($_[0]);
578
579	if (!$_[0]) {
580	aioreq_pri $pri;
581	add $grp aio_unlink $src;
582	}
583	};
584	} else {
585	$grp->result ($_[0]);	886	$grp->result ($_[0]);
		887
		888	unless ($_[0]) {
		889	aioreq_pri $pri;
		890	add $grp aio_unlink $src;
		891	}
586	}	892	};
		893	} else {
		894	$grp->result ($_[0]);
587	};	895	}
588
589	$grp
590	}	896	};
		897
		898	$grp
591	}	899	}
592		900
593	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	901	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
594		902
595	Scans a directory (similar to C<aio_readdir>) but additionally tries to	903	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
615		923
616	Implementation notes.	924	Implementation notes.
617		925
618	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	926	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
619		927
		928	If readdir returns file type information, then this is used directly to
		929	find directories.
		930
620	After reading the directory, the modification time, size etc. of the	931	Otherwise, after reading the directory, the modification time, size etc.
621	directory before and after the readdir is checked, and if they match (and	932	of the directory before and after the readdir is checked, and if they
622	isn't the current time), the link count will be used to decide how many	933	match (and isn't the current time), the link count will be used to decide
623	entries are directories (if >= 2). Otherwise, no knowledge of the number	934	how many entries are directories (if >= 2). Otherwise, no knowledge of the
624	of subdirectories will be assumed.	935	number of subdirectories will be assumed.
625		936
626	Then entries will be sorted into likely directories (everything without	937	Then entries will be sorted into likely directories a non-initial dot
627	a non-initial dot currently) and likely non-directories (everything	938	currently) and likely non-directories (see C<aio_readdirx>). Then every
628	else). Then every entry plus an appended C</.> will be C<stat>'ed,	939	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
629	likely directories first. If that succeeds, it assumes that the entry	940	in order of their inode numbers. If that succeeds, it assumes that the
630	is a directory or a symlink to directory (which will be checked	941	entry is a directory or a symlink to directory (which will be checked
631	seperately). This is often faster than stat'ing the entry itself because	942	separately). This is often faster than stat'ing the entry itself because
632	filesystems might detect the type of the entry without reading the inode	943	filesystems might detect the type of the entry without reading the inode
633	data (e.g. ext2fs filetype feature).	944	data (e.g. ext2fs filetype feature), even on systems that cannot return
		945	the filetype information on readdir.
634		946
635	If the known number of directories (link count - 2) has been reached, the	947	If the known number of directories (link count - 2) has been reached, the
636	rest of the entries is assumed to be non-directories.	948	rest of the entries is assumed to be non-directories.
637		949
638	This only works with certainty on POSIX (= UNIX) filesystems, which	950	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
643	directory counting heuristic.	955	directory counting heuristic.
644		956
645	=cut	957	=cut
646		958
647	sub aio_scandir($$;$) {	959	sub aio_scandir($$;$) {
648	aio_block {
649	my ($path, $maxreq, $cb) = @_;	960	my ($path, $maxreq, $cb) = @_;
650		961
651	my $pri = aioreq_pri;	962	my $pri = aioreq_pri;
652		963
653	my $grp = aio_group $cb;	964	my $grp = aio_group $cb;
654		965
655	$maxreq = 4 if $maxreq <= 0;	966	$maxreq = 4 if $maxreq <= 0;
656		967
657	# stat once	968	# stat once
		969	aioreq_pri $pri;
		970	add $grp aio_stat $path, sub {
		971	return $grp->result () if $_[0];
		972	my $now = time;
		973	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		974
		975	# read the directory entries
658	aioreq_pri $pri;	976	aioreq_pri $pri;
659	add $grp aio_stat $path, sub {	977	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		978	my $entries = shift
660	return $grp->result () if $_[0];	979	or return $grp->result ();
661	my $now = time;
662	my $hash1 = join ":", (stat _)[0,1,3,7,9];
663		980
664	# read the directory entries	981	# stat the dir another time
665	aioreq_pri $pri;	982	aioreq_pri $pri;
666	add $grp aio_readdir $path, sub {
667	my $entries = shift
668	or return $grp->result ();
669
670	# stat the dir another time
671	aioreq_pri $pri;
672	add $grp aio_stat $path, sub {	983	add $grp aio_stat $path, sub {
673	my $hash2 = join ":", (stat _)[0,1,3,7,9];	984	my $hash2 = join ":", (stat _)[0,1,3,7,9];
674		985
675	my $ndirs;	986	my $ndirs;
676		987
677	# take the slow route if anything looks fishy	988	# take the slow route if anything looks fishy
678	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	989	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
679	$ndirs = -1;	990	$ndirs = -1;
680	} else {	991	} else {
681	# if nlink == 2, we are finished	992	# if nlink == 2, we are finished
682	# on non-posix-fs's, we rely on nlink < 2	993	# for non-posix-fs's, we rely on nlink < 2
683	$ndirs = (stat _)[3] - 2	994	$ndirs = (stat _)[3] - 2
684	or return $grp->result ([], $entries);	995	or return $grp->result ([], $entries);
685	}	996	}
686		997
687	# sort into likely dirs and likely nondirs
688	# dirs == files without ".", short entries first
689	$entries = [map $_->[0],
690	sort { $b->[1] cmp $a->[1] }
691	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
692	@$entries];
693
694	my (@dirs, @nondirs);	998	my (@dirs, @nondirs);
695		999
696	my $statgrp = add $grp aio_group sub {	1000	my $statgrp = add $grp aio_group sub {
697	$grp->result (\@dirs, \@nondirs);	1001	$grp->result (\@dirs, \@nondirs);
698	};	1002	};
699		1003
700	limit $statgrp $maxreq;	1004	limit $statgrp $maxreq;
701	feed $statgrp sub {	1005	feed $statgrp sub {
702	return unless @$entries;	1006	return unless @$entries;
703	my $entry = pop @$entries;	1007	my $entry = shift @$entries;
704		1008
705	aioreq_pri $pri;	1009	aioreq_pri $pri;
706	add $statgrp aio_stat "$path/$entry/.", sub {	1010	add $statgrp aio_stat "$path/$entry/.", sub {
707	if ($_[0] < 0) {	1011	if ($_[0] < 0) {
708	push @nondirs, $entry;	1012	push @nondirs, $entry;
709	} else {	1013	} else {
710	# need to check for real directory	1014	# need to check for real directory
711	aioreq_pri $pri;	1015	aioreq_pri $pri;
712	add $statgrp aio_lstat "$path/$entry", sub {	1016	add $statgrp aio_lstat "$path/$entry", sub {
713	if (-d _) {	1017	if (-d _) {
714	push @dirs, $entry;	1018	push @dirs, $entry;
715		1019
716	unless (--$ndirs) {	1020	unless (--$ndirs) {
717	push @nondirs, @$entries;	1021	push @nondirs, @$entries;
718	feed $statgrp;	1022	feed $statgrp;
719	}
720	} else {
721	push @nondirs, $entry;
722	}	1023	}
		1024	} else {
		1025	push @nondirs, $entry;
723	}	1026	}
724	}	1027	}
725	};	1028	}
726	};	1029	};
727	};	1030	};
728	};	1031	};
729	};	1032	};
730
731	$grp
732	}	1033	};
		1034
		1035	$grp
733	}	1036	}
734		1037
735	=item aio_rmtree $path, $callback->($status)	1038	=item aio_rmtree $path, $callback->($status)
736		1039
737	Delete a directory tree starting (and including) C<$path>, return the	1040	Delete a directory tree starting (and including) C<$path>, return the
…		…
741		1044
742	=cut	1045	=cut
743		1046
744	sub aio_rmtree;	1047	sub aio_rmtree;
745	sub aio_rmtree($;$) {	1048	sub aio_rmtree($;$) {
746	aio_block {
747	my ($path, $cb) = @_;	1049	my ($path, $cb) = @_;
748		1050
749	my $pri = aioreq_pri;	1051	my $pri = aioreq_pri;
750	my $grp = aio_group $cb;	1052	my $grp = aio_group $cb;
751		1053
752	aioreq_pri $pri;	1054	aioreq_pri $pri;
753	add $grp aio_scandir $path, 0, sub {	1055	add $grp aio_scandir $path, 0, sub {
754	my ($dirs, $nondirs) = @_;	1056	my ($dirs, $nondirs) = @_;
755		1057
756	my $dirgrp = aio_group sub {	1058	my $dirgrp = aio_group sub {
757	add $grp aio_rmdir $path, sub {	1059	add $grp aio_rmdir $path, sub {
758	$grp->result ($_[0]);	1060	$grp->result ($_[0]);
759	};
760	};	1061	};
761
762	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
763	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
764
765	add $grp $dirgrp;
766	};	1062	};
767		1063
768	$grp	1064	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1065	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1066
		1067	add $grp $dirgrp;
769	}	1068	};
		1069
		1070	$grp
770	}	1071	}
		1072
		1073	=item aio_sync $callback->($status)
		1074
		1075	Asynchronously call sync and call the callback when finished.
771		1076
772	=item aio_fsync $fh, $callback->($status)	1077	=item aio_fsync $fh, $callback->($status)
773		1078
774	Asynchronously call fsync on the given filehandle and call the callback	1079	Asynchronously call fsync on the given filehandle and call the callback
775	with the fsync result code.	1080	with the fsync result code.
…		…
779	Asynchronously call fdatasync on the given filehandle and call the	1084	Asynchronously call fdatasync on the given filehandle and call the
780	callback with the fdatasync result code.	1085	callback with the fdatasync result code.
781		1086
782	If this call isn't available because your OS lacks it or it couldn't be	1087	If this call isn't available because your OS lacks it or it couldn't be
783	detected, it will be emulated by calling C<fsync> instead.	1088	detected, it will be emulated by calling C<fsync> instead.
		1089
		1090	=item aio_syncfs $fh, $callback->($status)
		1091
		1092	Asynchronously call the syncfs syscall to sync the filesystem associated
		1093	to the given filehandle and call the callback with the syncfs result
		1094	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1095	errno to C<ENOSYS> nevertheless.
		1096
		1097	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1098
		1099	Sync the data portion of the file specified by C<$offset> and C<$length>
		1100	to disk (but NOT the metadata), by calling the Linux-specific
		1101	sync_file_range call. If sync_file_range is not available or it returns
		1102	ENOSYS, then fdatasync or fsync is being substituted.
		1103
		1104	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1105	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1106	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1107	manpage for details.
		1108
		1109	=item aio_pathsync $path, $callback->($status)
		1110
		1111	This request tries to open, fsync and close the given path. This is a
		1112	composite request intended to sync directories after directory operations
		1113	(E.g. rename). This might not work on all operating systems or have any
		1114	specific effect, but usually it makes sure that directory changes get
		1115	written to disc. It works for anything that can be opened for read-only,
		1116	not just directories.
		1117
		1118	Future versions of this function might fall back to other methods when
		1119	C<fsync> on the directory fails (such as calling C<sync>).
		1120
		1121	Passes C<0> when everything went ok, and C<-1> on error.
		1122
		1123	=cut
		1124
		1125	sub aio_pathsync($;$) {
		1126	my ($path, $cb) = @_;
		1127
		1128	my $pri = aioreq_pri;
		1129	my $grp = aio_group $cb;
		1130
		1131	aioreq_pri $pri;
		1132	add $grp aio_open $path, O_RDONLY, 0, sub {
		1133	my ($fh) = @_;
		1134	if ($fh) {
		1135	aioreq_pri $pri;
		1136	add $grp aio_fsync $fh, sub {
		1137	$grp->result ($_[0]);
		1138
		1139	aioreq_pri $pri;
		1140	add $grp aio_close $fh;
		1141	};
		1142	} else {
		1143	$grp->result (-1);
		1144	}
		1145	};
		1146
		1147	$grp
		1148	}
		1149
		1150	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1151
		1152	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1153	scalars (see the C<IO::AIO::mmap> function, although it also works on data
		1154	scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
		1155	scalar must only be modified in-place while an aio operation is pending on
		1156	it).
		1157
		1158	It calls the C<msync> function of your OS, if available, with the memory
		1159	area starting at C<$offset> in the string and ending C<$length> bytes
		1160	later. If C<$length> is negative, counts from the end, and if C<$length>
		1161	is C<undef>, then it goes till the end of the string. The flags can be
		1162	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1163	C<IO::AIO::MS_SYNC>.
		1164
		1165	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1166
		1167	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1168	scalars.
		1169
		1170	It touches (reads or writes) all memory pages in the specified
		1171	range inside the scalar. All caveats and parameters are the same
		1172	as for C<aio_msync>, above, except for flags, which must be either
		1173	C<0> (which reads all pages and ensures they are instantiated) or
		1174	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1175	writing an octet from it, which dirties the page).
		1176
		1177	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
		1178
		1179	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1180	scalars.
		1181
		1182	It reads in all the pages of the underlying storage into memory (if any)
		1183	and locks them, so they are not getting swapped/paged out or removed.
		1184
		1185	If C<$length> is undefined, then the scalar will be locked till the end.
		1186
		1187	On systems that do not implement C<mlock>, this function returns C<-1>
		1188	and sets errno to C<ENOSYS>.
		1189
		1190	Note that the corresponding C<munlock> is synchronous and is
		1191	documented under L<MISCELLANEOUS FUNCTIONS>.
		1192
		1193	Example: open a file, mmap and mlock it - both will be undone when
		1194	C<$data> gets destroyed.
		1195
		1196	open my $fh, "<", $path or die "$path: $!";
		1197	my $data;
		1198	IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
		1199	aio_mlock $data; # mlock in background
		1200
		1201	=item aio_mlockall $flags, $callback->($status)
		1202
		1203	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1204	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
		1205
		1206	On systems that do not implement C<mlockall>, this function returns C<-1>
		1207	and sets errno to C<ENOSYS>.
		1208
		1209	Note that the corresponding C<munlockall> is synchronous and is
		1210	documented under L<MISCELLANEOUS FUNCTIONS>.
		1211
		1212	Example: asynchronously lock all current and future pages into memory.
		1213
		1214	aio_mlockall IO::AIO::MCL_FUTURE;
784		1215
785	=item aio_group $callback->(...)	1216	=item aio_group $callback->(...)
786		1217
787	This is a very special aio request: Instead of doing something, it is a	1218	This is a very special aio request: Instead of doing something, it is a
788	container for other aio requests, which is useful if you want to bundle	1219	container for other aio requests, which is useful if you want to bundle
…		…
838	=item cancel $req	1269	=item cancel $req
839		1270
840	Cancels the request, if possible. Has the effect of skipping execution	1271	Cancels the request, if possible. Has the effect of skipping execution
841	when entering the B<execute> state and skipping calling the callback when	1272	when entering the B<execute> state and skipping calling the callback when
842	entering the the B<result> state, but will leave the request otherwise	1273	entering the the B<result> state, but will leave the request otherwise
843	untouched. That means that requests that currently execute will not be	1274	untouched (with the exception of readdir). That means that requests that
844	stopped and resources held by the request will not be freed prematurely.	1275	currently execute will not be stopped and resources held by the request
		1276	will not be freed prematurely.
845		1277
846	=item cb $req $callback->(...)	1278	=item cb $req $callback->(...)
847		1279
848	Replace (or simply set) the callback registered to the request.	1280	Replace (or simply set) the callback registered to the request.
849		1281
…		…
900	Their lifetime, simplified, looks like this: when they are empty, they	1332	Their lifetime, simplified, looks like this: when they are empty, they
901	will finish very quickly. If they contain only requests that are in the	1333	will finish very quickly. If they contain only requests that are in the
902	C<done> state, they will also finish. Otherwise they will continue to	1334	C<done> state, they will also finish. Otherwise they will continue to
903	exist.	1335	exist.
904		1336
905	That means after creating a group you have some time to add requests. And	1337	That means after creating a group you have some time to add requests
906	in the callbacks of those requests, you can add further requests to the	1338	(precisely before the callback has been invoked, which is only done within
907	group. And only when all those requests have finished will the the group	1339	the C<poll_cb>). And in the callbacks of those requests, you can add
908	itself finish.	1340	further requests to the group. And only when all those requests have
		1341	finished will the the group itself finish.
909		1342
910	=over 4	1343	=over 4
911		1344
912	=item add $grp ...	1345	=item add $grp ...
913		1346
…		…
922	=item $grp->cancel_subs	1355	=item $grp->cancel_subs
923		1356
924	Cancel all subrequests and clears any feeder, but not the group request	1357	Cancel all subrequests and clears any feeder, but not the group request
925	itself. Useful when you queued a lot of events but got a result early.	1358	itself. Useful when you queued a lot of events but got a result early.
926		1359
		1360	The group request will finish normally (you cannot add requests to the
		1361	group).
		1362
927	=item $grp->result (...)	1363	=item $grp->result (...)
928		1364
929	Set the result value(s) that will be passed to the group callback when all	1365	Set the result value(s) that will be passed to the group callback when all
930	subrequests have finished and set thre groups errno to the current value	1366	subrequests have finished and set the groups errno to the current value
931	of errno (just like calling C<errno> without an error number). By default,	1367	of errno (just like calling C<errno> without an error number). By default,
932	no argument will be passed and errno is zero.	1368	no argument will be passed and errno is zero.
933		1369
934	=item $grp->errno ([$errno])	1370	=item $grp->errno ([$errno])
935		1371
…		…
946	=item feed $grp $callback->($grp)	1382	=item feed $grp $callback->($grp)
947		1383
948	Sets a feeder/generator on this group: every group can have an attached	1384	Sets a feeder/generator on this group: every group can have an attached
949	generator that generates requests if idle. The idea behind this is that,	1385	generator that generates requests if idle. The idea behind this is that,
950	although you could just queue as many requests as you want in a group,	1386	although you could just queue as many requests as you want in a group,
951	this might starve other requests for a potentially long time. For	1387	this might starve other requests for a potentially long time. For example,
952	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1388	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
953	requests, delaying any later requests for a long time.	1389	delaying any later requests for a long time.
954		1390
955	To avoid this, and allow incremental generation of requests, you can	1391	To avoid this, and allow incremental generation of requests, you can
956	instead a group and set a feeder on it that generates those requests. The	1392	instead a group and set a feeder on it that generates those requests. The
957	feed callback will be called whenever there are few enough (see C<limit>,	1393	feed callback will be called whenever there are few enough (see C<limit>,
958	below) requests active in the group itself and is expected to queue more	1394	below) requests active in the group itself and is expected to queue more
…		…
962	not impose any limits).	1398	not impose any limits).
963		1399
964	If the feed does not queue more requests when called, it will be	1400	If the feed does not queue more requests when called, it will be
965	automatically removed from the group.	1401	automatically removed from the group.
966		1402
967	If the feed limit is C<0>, it will be set to C<2> automatically.	1403	If the feed limit is C<0> when this method is called, it will be set to
		1404	C<2> automatically.
968		1405
969	Example:	1406	Example:
970		1407
971	# stat all files in @files, but only ever use four aio requests concurrently:	1408	# stat all files in @files, but only ever use four aio requests concurrently:
972		1409
…		…
984	Sets the feeder limit for the group: The feeder will be called whenever	1421	Sets the feeder limit for the group: The feeder will be called whenever
985	the group contains less than this many requests.	1422	the group contains less than this many requests.
986		1423
987	Setting the limit to C<0> will pause the feeding process.	1424	Setting the limit to C<0> will pause the feeding process.
988		1425
		1426	The default value for the limit is C<0>, but note that setting a feeder
		1427	automatically bumps it up to C<2>.
		1428
989	=back	1429	=back
990		1430
991	=head2 SUPPORT FUNCTIONS	1431	=head2 SUPPORT FUNCTIONS
992		1432
993	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1433	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
995	=over 4	1435	=over 4
996		1436
997	=item $fileno = IO::AIO::poll_fileno	1437	=item $fileno = IO::AIO::poll_fileno
998		1438
999	Return the I<request result pipe file descriptor>. This filehandle must be	1439	Return the I<request result pipe file descriptor>. This filehandle must be
1000	polled for reading by some mechanism outside this module (e.g. Event or	1440	polled for reading by some mechanism outside this module (e.g. EV, Glib,
1001	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1441	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1002	to call C<poll_cb> to check the results.	1442	you have to call C<poll_cb> to check the results.
1003		1443
1004	See C<poll_cb> for an example.	1444	See C<poll_cb> for an example.
1005		1445
1006	=item IO::AIO::poll_cb	1446	=item IO::AIO::poll_cb
1007		1447
1008	Process some outstanding events on the result pipe. You have to call this	1448	Process some outstanding events on the result pipe. You have to call
1009	regularly. Returns the number of events processed. Returns immediately	1449	this regularly. Returns C<0> if all events could be processed (or there
1010	when no events are outstanding. The amount of events processed depends on	1450	were no events to process), or C<-1> if it returned earlier for whatever
1011	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1451	reason. Returns immediately when no events are outstanding. The amount of
		1452	events processed depends on the settings of C<IO::AIO::max_poll_req> and
		1453	C<IO::AIO::max_poll_time>.
1012		1454
1013	If not all requests were processed for whatever reason, the filehandle	1455	If not all requests were processed for whatever reason, the filehandle
1014	will still be ready when C<poll_cb> returns.	1456	will still be ready when C<poll_cb> returns, so normally you don't have to
		1457	do anything special to have it called later.
		1458
		1459	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1460	ready, it can be beneficial to call this function from loops which submit
		1461	a lot of requests, to make sure the results get processed when they become
		1462	available and not just when the loop is finished and the event loop takes
		1463	over again. This function returns very fast when there are no outstanding
		1464	requests.
1015		1465
1016	Example: Install an Event watcher that automatically calls	1466	Example: Install an Event watcher that automatically calls
1017	IO::AIO::poll_cb with high priority:	1467	IO::AIO::poll_cb with high priority (more examples can be found in the
		1468	SYNOPSIS section, at the top of this document):
1018		1469
1019	Event->io (fd => IO::AIO::poll_fileno,	1470	Event->io (fd => IO::AIO::poll_fileno,
1020	poll => 'r', async => 1,	1471	poll => 'r', async => 1,
1021	cb => \&IO::AIO::poll_cb);	1472	cb => \&IO::AIO::poll_cb);
		1473
		1474	=item IO::AIO::poll_wait
		1475
		1476	If there are any outstanding requests and none of them in the result
		1477	phase, wait till the result filehandle becomes ready for reading (simply
		1478	does a C<select> on the filehandle. This is useful if you want to
		1479	synchronously wait for some requests to finish).
		1480
		1481	See C<nreqs> for an example.
		1482
		1483	=item IO::AIO::poll
		1484
		1485	Waits until some requests have been handled.
		1486
		1487	Returns the number of requests processed, but is otherwise strictly
		1488	equivalent to:
		1489
		1490	IO::AIO::poll_wait, IO::AIO::poll_cb
		1491
		1492	=item IO::AIO::flush
		1493
		1494	Wait till all outstanding AIO requests have been handled.
		1495
		1496	Strictly equivalent to:
		1497
		1498	IO::AIO::poll_wait, IO::AIO::poll_cb
		1499	while IO::AIO::nreqs;
1022		1500
1023	=item IO::AIO::max_poll_reqs $nreqs	1501	=item IO::AIO::max_poll_reqs $nreqs
1024		1502
1025	=item IO::AIO::max_poll_time $seconds	1503	=item IO::AIO::max_poll_time $seconds
1026		1504
…		…
1051	# use a low priority so other tasks have priority	1529	# use a low priority so other tasks have priority
1052	Event->io (fd => IO::AIO::poll_fileno,	1530	Event->io (fd => IO::AIO::poll_fileno,
1053	poll => 'r', nice => 1,	1531	poll => 'r', nice => 1,
1054	cb => &IO::AIO::poll_cb);	1532	cb => &IO::AIO::poll_cb);
1055		1533
1056	=item IO::AIO::poll_wait
1057
1058	If there are any outstanding requests and none of them in the result
1059	phase, wait till the result filehandle becomes ready for reading (simply
1060	does a C<select> on the filehandle. This is useful if you want to
1061	synchronously wait for some requests to finish).
1062
1063	See C<nreqs> for an example.
1064
1065	=item IO::AIO::poll
1066
1067	Waits until some requests have been handled.
1068
1069	Returns the number of requests processed, but is otherwise strictly
1070	equivalent to:
1071
1072	IO::AIO::poll_wait, IO::AIO::poll_cb
1073
1074	=item IO::AIO::flush
1075
1076	Wait till all outstanding AIO requests have been handled.
1077
1078	Strictly equivalent to:
1079
1080	IO::AIO::poll_wait, IO::AIO::poll_cb
1081	while IO::AIO::nreqs;
1082
1083	=back	1534	=back
1084		1535
1085	=head3 CONTROLLING THE NUMBER OF THREADS	1536	=head3 CONTROLLING THE NUMBER OF THREADS
1086		1537
1087	=over	1538	=over
…		…
1120		1571
1121	Under normal circumstances you don't need to call this function.	1572	Under normal circumstances you don't need to call this function.
1122		1573
1123	=item IO::AIO::max_idle $nthreads	1574	=item IO::AIO::max_idle $nthreads
1124		1575
1125	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1576	Limit the number of threads (default: 4) that are allowed to idle
1126	threads that did not get a request to process within 10 seconds). That	1577	(i.e., threads that did not get a request to process within the idle
1127	means if a thread becomes idle while C<$nthreads> other threads are also	1578	timeout (default: 10 seconds). That means if a thread becomes idle while
1128	idle, it will free its resources and exit.	1579	C<$nthreads> other threads are also idle, it will free its resources and
		1580	exit.
1129		1581
1130	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1582	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1131	to allow for extremely high load situations, but want to free resources	1583	to allow for extremely high load situations, but want to free resources
1132	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1584	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1133		1585
1134	The default is probably ok in most situations, especially if thread	1586	The default is probably ok in most situations, especially if thread
1135	creation is fast. If thread creation is very slow on your system you might	1587	creation is fast. If thread creation is very slow on your system you might
1136	want to use larger values.	1588	want to use larger values.
1137		1589
		1590	=item IO::AIO::idle_timeout $seconds
		1591
		1592	Sets the minimum idle timeout (default 10) after which worker threads are
		1593	allowed to exit. SEe C<IO::AIO::max_idle>.
		1594
1138	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1595	=item IO::AIO::max_outstanding $maxreqs
		1596
		1597	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1598	you do queue up more than this number of requests, the next call to
		1599	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1600	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1601	longer exceeded.
		1602
		1603	In other words, this setting does not enforce a queue limit, but can be
		1604	used to make poll functions block if the limit is exceeded.
1139		1605
1140	This is a very bad function to use in interactive programs because it	1606	This is a very bad function to use in interactive programs because it
1141	blocks, and a bad way to reduce concurrency because it is inexact: Better	1607	blocks, and a bad way to reduce concurrency because it is inexact: Better
1142	use an C<aio_group> together with a feed callback.	1608	use an C<aio_group> together with a feed callback.
1143		1609
1144	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1610	It's main use is in scripts without an event loop - when you want to stat
1145	to queue up more than this number of requests, the next call to the	1611	a lot of files, you can write somehting like this:
1146	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1147	function will block until the limit is no longer exceeded.
1148		1612
1149	The default value is very large, so there is no practical limit on the	1613	IO::AIO::max_outstanding 32;
1150	number of outstanding requests.
1151		1614
1152	You can still queue as many requests as you want. Therefore,	1615	for my $path (...) {
1153	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1616	aio_stat $path , ...;
1154	as a stop gap to shield against fatal memory overflow (with large values).	1617	IO::AIO::poll_cb;
		1618	}
		1619
		1620	IO::AIO::flush;
		1621
		1622	The call to C<poll_cb> inside the loop will normally return instantly, but
		1623	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1624	some requests have been handled. This keeps the loop from pushing a large
		1625	number of C<aio_stat> requests onto the queue.
		1626
		1627	The default value for C<max_outstanding> is very large, so there is no
		1628	practical limit on the number of outstanding requests.
1155		1629
1156	=back	1630	=back
1157		1631
1158	=head3 STATISTICAL INFORMATION	1632	=head3 STATISTICAL INFORMATION
1159		1633
…		…
1179	Returns the number of requests currently in the pending state (executed,	1653	Returns the number of requests currently in the pending state (executed,
1180	but not yet processed by poll_cb).	1654	but not yet processed by poll_cb).
1181		1655
1182	=back	1656	=back
1183		1657
		1658	=head3 MISCELLANEOUS FUNCTIONS
		1659
		1660	IO::AIO implements some functions that might be useful, but are not
		1661	asynchronous.
		1662
		1663	=over 4
		1664
		1665	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1666
		1667	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1668	but is blocking (this makes most sense if you know the input data is
		1669	likely cached already and the output filehandle is set to non-blocking
		1670	operations).
		1671
		1672	Returns the number of bytes copied, or C<-1> on error.
		1673
		1674	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1675
		1676	Simply calls the C<posix_fadvise> function (see its
		1677	manpage for details). The following advice constants are
		1678	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1679	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1680	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1681
		1682	On systems that do not implement C<posix_fadvise>, this function returns
		1683	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1684
		1685	=item IO::AIO::madvise $scalar, $offset, $len, $advice
		1686
		1687	Simply calls the C<posix_madvise> function (see its
		1688	manpage for details). The following advice constants are
		1689	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
		1690	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
		1691
		1692	On systems that do not implement C<posix_madvise>, this function returns
		1693	ENOSYS, otherwise the return value of C<posix_madvise>.
		1694
		1695	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
		1696
		1697	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
		1698	$scalar (see its manpage for details). The following protect
		1699	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
		1700	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
		1701
		1702	On systems that do not implement C<mprotect>, this function returns
		1703	ENOSYS, otherwise the return value of C<mprotect>.
		1704
		1705	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
		1706
		1707	Memory-maps a file (or anonymous memory range) and attaches it to the
		1708	given C<$scalar>, which will act like a string scalar.
		1709
		1710	The only operations allowed on the scalar are C<substr>/C<vec> that don't
		1711	change the string length, and most read-only operations such as copying it
		1712	or searching it with regexes and so on.
		1713
		1714	Anything else is unsafe and will, at best, result in memory leaks.
		1715
		1716	The memory map associated with the C<$scalar> is automatically removed
		1717	when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
		1718	C<IO::AIO::munmap> functions are called.
		1719
		1720	This calls the C<mmap>(2) function internally. See your system's manual
		1721	page for details on the C<$length>, C<$prot> and C<$flags> parameters.
		1722
		1723	The C<$length> must be larger than zero and smaller than the actual
		1724	filesize.
		1725
		1726	C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
		1727	C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
		1728
		1729	C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
		1730	C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
		1731	not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
		1732	(which is set to C<MAP_ANON> if your system only provides this
		1733	constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
		1734	C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
		1735	C<IO::AIO::MAP_NONBLOCK>
		1736
		1737	If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
		1738
		1739	C<$offset> is the offset from the start of the file - it generally must be
		1740	a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
		1741
		1742	Example:
		1743
		1744	use Digest::MD5;
		1745	use IO::AIO;
		1746
		1747	open my $fh, "<verybigfile"
		1748	or die "$!";
		1749
		1750	IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
		1751	or die "verybigfile: $!";
		1752
		1753	my $fast_md5 = md5 $data;
		1754
		1755	=item IO::AIO::munmap $scalar
		1756
		1757	Removes a previous mmap and undefines the C<$scalar>.
		1758
		1759	=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
		1760
		1761	Calls the C<munlock> function, undoing the effects of a previous
		1762	C<aio_mlock> call (see its description for details).
		1763
		1764	=item IO::AIO::munlockall
		1765
		1766	Calls the C<munlockall> function.
		1767
		1768	On systems that do not implement C<munlockall>, this function returns
		1769	ENOSYS, otherwise the return value of C<munlockall>.
		1770
		1771	=back
		1772
1184	=cut	1773	=cut
1185		1774
1186	# support function to convert a fd into a perl filehandle
1187	sub _fd2fh {
1188	return undef if $_[0] < 0;
1189
1190	# try to generate nice filehandles
1191	my $sym = "IO::AIO::fd#$_[0]";
1192	local *$sym;
1193
1194	open *$sym, "+<&=$_[0]" # usually works under any unix
1195	or open *$sym, "<&=$_[0]" # cygwin needs this
1196	or open *$sym, ">&=$_[0]" # or this
1197	or return undef;
1198
1199	*$sym
1200	}
1201
1202	min_parallel 8;	1775	min_parallel 8;
1203		1776
1204	END { flush }	1777	END { flush }
1205		1778
1206	1;	1779	1;
1207		1780
		1781	=head1 EVENT LOOP INTEGRATION
		1782
		1783	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1784	automatically into many event loops:
		1785
		1786	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1787	use AnyEvent::AIO;
		1788
		1789	You can also integrate IO::AIO manually into many event loops, here are
		1790	some examples of how to do this:
		1791
		1792	# EV integration
		1793	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1794
		1795	# Event integration
		1796	Event->io (fd => IO::AIO::poll_fileno,
		1797	poll => 'r',
		1798	cb => \&IO::AIO::poll_cb);
		1799
		1800	# Glib/Gtk2 integration
		1801	add_watch Glib::IO IO::AIO::poll_fileno,
		1802	in => sub { IO::AIO::poll_cb; 1 };
		1803
		1804	# Tk integration
		1805	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1806	readable => \&IO::AIO::poll_cb);
		1807
		1808	# Danga::Socket integration
		1809	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1810	\&IO::AIO::poll_cb);
		1811
1208	=head2 FORK BEHAVIOUR	1812	=head2 FORK BEHAVIOUR
1209		1813
1210	This module should do "the right thing" when the process using it forks:	1814	Usage of pthreads in a program changes the semantics of fork
		1815	considerably. Specifically, only async-safe functions can be called after
		1816	fork. Perl doesn't know about this, so in general, you cannot call fork
		1817	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		1818	pthreads, so this applies, but many other extensions and (for inexplicable
		1819	reasons) perl itself often is linked against pthreads, so this limitation
		1820	applies to quite a lot of perls.
1211		1821
1212	Before the fork, IO::AIO enters a quiescent state where no requests	1822	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1213	can be added in other threads and no results will be processed. After	1823	only works in the process that loaded it. Forking is fully supported, but
1214	the fork the parent simply leaves the quiescent state and continues	1824	using IO::AIO in the child is not.
1215	request/result processing, while the child frees the request/result queue
1216	(so that the requests started before the fork will only be handled in the
1217	parent). Threads will be started on demand until the limit set in the
1218	parent process has been reached again.
1219		1825
1220	In short: the parent will, after a short pause, continue as if fork had	1826	You might get around by not I<using> IO::AIO before (or after)
1221	not been called, while the child will act as if IO::AIO has not been used	1827	forking. You could also try to call the L<IO::AIO::reinit> function in the
1222	yet.	1828	child:
		1829
		1830	=over 4
		1831
		1832	=item IO::AIO::reinit
		1833
		1834	Abandons all current requests and I/O threads and simply reinitialises all
		1835	data structures. This is not an operation supported by any standards, but
		1836	happens to work on GNU/Linux and some newer BSD systems.
		1837
		1838	The only reasonable use for this function is to call it after forking, if
		1839	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1840	the process will result in undefined behaviour. Calling it at any time
		1841	will also result in any undefined (by POSIX) behaviour.
		1842
		1843	=back
1223		1844
1224	=head2 MEMORY USAGE	1845	=head2 MEMORY USAGE
1225		1846
1226	Per-request usage:	1847	Per-request usage:
1227		1848
…		…
1229	bytes of memory. In addition, stat requests need a stat buffer (possibly	1850	bytes of memory. In addition, stat requests need a stat buffer (possibly
1230	a few hundred bytes), readdir requires a result buffer and so on. Perl	1851	a few hundred bytes), readdir requires a result buffer and so on. Perl
1231	scalars and other data passed into aio requests will also be locked and	1852	scalars and other data passed into aio requests will also be locked and
1232	will consume memory till the request has entered the done state.	1853	will consume memory till the request has entered the done state.
1233		1854
1234	This is now awfully much, so queuing lots of requests is not usually a	1855	This is not awfully much, so queuing lots of requests is not usually a
1235	problem.	1856	problem.
1236		1857
1237	Per-thread usage:	1858	Per-thread usage:
1238		1859
1239	In the execution phase, some aio requests require more memory for	1860	In the execution phase, some aio requests require more memory for
…		…
1244		1865
1245	Known bugs will be fixed in the next release.	1866	Known bugs will be fixed in the next release.
1246		1867
1247	=head1 SEE ALSO	1868	=head1 SEE ALSO
1248		1869
1249	L<Coro::AIO>.	1870	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1871	more natural syntax.
1250		1872
1251	=head1 AUTHOR	1873	=head1 AUTHOR
1252		1874
1253	Marc Lehmann <schmorp@schmorp.de>	1875	Marc Lehmann <schmorp@schmorp.de>
1254	http://home.schmorp.de/	1876	http://home.schmorp.de/

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