[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.87 by root, Sun Oct 29 00:52:02 2006 UTC vs.
Revision 1.175 by root, Sun Jan 10 20:37:33 2010 UTC

…		…
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", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
30	# AnyEvent integration
31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33
34	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',
37	cb => \&IO::AIO::poll_cb);
38
39	# Glib/Gtk2 integration
40	add_watch Glib::IO IO::AIO::poll_fileno,
41	in => sub { IO::AIO::poll_cb; 1 };
42
43	# Tk integration
44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
45	readable => \&IO::AIO::poll_cb);
46
47	# Danga::Socket integration
48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
49	\&IO::AIO::poll_cb);
50
51	=head1 DESCRIPTION	31	=head1 DESCRIPTION
52		32
53	This module implements asynchronous I/O using whatever means your	33	This module implements asynchronous I/O using whatever means your
54	operating system supports.	34	operating system supports. It is implemented as an interface to C<libeio>
		35	(L<http://software.schmorp.de/pkg/libeio.html>).
55		36
56	Asynchronous means that operations that can normally block your program	37	Asynchronous means that operations that can normally block your program
57	(e.g. reading from disk) will be done asynchronously: the operation	38	(e.g. reading from disk) will be done asynchronously: the operation
58	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
59	is extremely useful for programs that need to stay interactive even	40	is extremely useful for programs that need to stay interactive even
…		…
61	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
62	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
63	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
64	concurrently.	45	concurrently.
65		46
66	While this works on all types of file descriptors (for example sockets),	47	While most of this works on all types of file descriptors (for
67	using these functions on file descriptors that support nonblocking	48	example sockets), using these functions on file descriptors that
68	operation (again, sockets, pipes etc.) is very inefficient. Use an event	49	support nonblocking operation (again, sockets, pipes etc.) is
69	loop for that (such as the L<Event\|Event> module): IO::AIO will naturally	50	very inefficient. Use an event loop for that (such as the L<EV>
70	fit into such an event loop itself.	51	module): IO::AIO will naturally fit into such an event loop itself.
71		52
72	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
73	requests and signal their completion. You don't need thread support	54	requests and signal their completion. You don't need thread support
74	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
75	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
…		…
77	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
78	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
79	aio_write, so the remaining functionality would have to be implemented	60	aio_write, so the remaining functionality would have to be implemented
80	using threads anyway.	61	using threads anyway.
81		62
82	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,
83	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
84	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
85	never call C<poll_cb> (or other C<aio_> functions) recursively.	66	call C<poll_cb> (or other C<aio_> functions) recursively.
86		67
87	=head2 EXAMPLE	68	=head2 EXAMPLE
88		69
89	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
90	F</etc/passwd> asynchronously:	71	F</etc/passwd> asynchronously:
91		72
92	use Fcntl;	73	use Fcntl;
93	use Event;	74	use EV;
94	use IO::AIO;	75	use IO::AIO;
95		76
96	# register the IO::AIO callback with Event	77	# register the IO::AIO callback with EV
97	Event->io (fd => IO::AIO::poll_fileno,	78	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
98	poll => 'r',
99	cb => \&IO::AIO::poll_cb);
100		79
101	# queue the request to open /etc/passwd	80	# queue the request to open /etc/passwd
102	aio_open "/etc/passwd", O_RDONLY, 0, sub {	81	aio_open "/etc/passwd", O_RDONLY, 0, sub {
103	my $fh = $_[0]	82	my $fh = shift
104	or die "error while opening: $!";	83	or die "error while opening: $!";
105		84
106	# stat'ing filehandles is generally non-blocking	85	# stat'ing filehandles is generally non-blocking
107	my $size = -s $fh;	86	my $size = -s $fh;
108		87
…		…
116		95
117	# file contents now in $contents	96	# file contents now in $contents
118	print $contents;	97	print $contents;
119		98
120	# exit event loop and program	99	# exit event loop and program
121	Event::unloop;	100	EV::unloop;
122	};	101	};
123	};	102	};
124		103
125	# possibly queue up other requests, or open GUI windows,	104	# possibly queue up other requests, or open GUI windows,
126	# check for sockets etc. etc.	105	# check for sockets etc. etc.
127		106
128	# process events as long as there are some:	107	# process events as long as there are some:
129	Event::loop;	108	EV::loop;
130		109
131	=head1 REQUEST ANATOMY AND LIFETIME	110	=head1 REQUEST ANATOMY AND LIFETIME
132		111
133	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
134	directly visible to Perl.	113	directly visible to Perl.
…		…
176	Request has reached the end of its lifetime and holds no resources anymore	155	Request has reached the end of its lifetime and holds no resources anymore
177	(except possibly for the Perl object, but its connection to the actual	156	(except possibly for the Perl object, but its connection to the actual
178	aio request is severed and calling its methods will either do nothing or	157	aio request is severed and calling its methods will either do nothing or
179	result in a runtime error).	158	result in a runtime error).
180		159
		160	=back
		161
181	=cut	162	=cut
182		163
183	package IO::AIO;	164	package IO::AIO;
184		165
185	no warnings;	166	use Carp ();
186	use strict 'vars';	167
		168	use common::sense;
187		169
188	use base 'Exporter';	170	use base 'Exporter';
189		171
190	BEGIN {	172	BEGIN {
191	our $VERSION = '2.1';	173	our $VERSION = '3.5';
192		174
193	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
194	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
195	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
196	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_statvfs);
		183
197	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	184	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
198	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	185	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
199	min_parallel max_parallel max_idle	186	min_parallel max_parallel max_idle
200	nreqs nready npending nthreads	187	nreqs nready npending nthreads
201	max_poll_time max_poll_reqs);	188	max_poll_time max_poll_reqs
		189	sendfile fadvise);
		190
		191	push @AIO_REQ, qw(aio_busy); # not exported
202		192
203	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	193	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
204		194
205	require XSLoader;	195	require XSLoader;
206	XSLoader::load ("IO::AIO", $VERSION);	196	XSLoader::load ("IO::AIO", $VERSION);
207	}	197	}
208		198
209	=head1 FUNCTIONS	199	=head1 FUNCTIONS
		200
		201	=head2 QUICK OVERVIEW
		202
		203	This section simply lists the prototypes of the most important functions
		204	for quick reference. See the following sections for function-by-function
		205	documentation.
		206
		207	aio_open $pathname, $flags, $mode, $callback->($fh)
		208	aio_close $fh, $callback->($status)
		209	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		210	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
		211	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
		212	aio_readahead $fh,$offset,$length, $callback->($retval)
		213	aio_stat $fh_or_path, $callback->($status)
		214	aio_lstat $fh, $callback->($status)
		215	aio_statvfs $fh_or_path, $callback->($statvfs)
		216	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		217	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		218	aio_truncate $fh_or_path, $offset, $callback->($status)
		219	aio_chmod $fh_or_path, $mode, $callback->($status)
		220	aio_unlink $pathname, $callback->($status)
		221	aio_mknod $path, $mode, $dev, $callback->($status)
		222	aio_link $srcpath, $dstpath, $callback->($status)
		223	aio_symlink $srcpath, $dstpath, $callback->($status)
		224	aio_readlink $path, $callback->($link)
		225	aio_rename $srcpath, $dstpath, $callback->($status)
		226	aio_mkdir $pathname, $mode, $callback->($status)
		227	aio_rmdir $pathname, $callback->($status)
		228	aio_readdir $pathname, $callback->($entries)
		229	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		230	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
		231	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		232	aio_load $path, $data, $callback->($status)
		233	aio_copy $srcpath, $dstpath, $callback->($status)
		234	aio_move $srcpath, $dstpath, $callback->($status)
		235	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
		236	aio_rmtree $path, $callback->($status)
		237	aio_sync $callback->($status)
		238	aio_fsync $fh, $callback->($status)
		239	aio_fdatasync $fh, $callback->($status)
		240	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		241	aio_pathsync $path, $callback->($status)
		242	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		243	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		244	aio_group $callback->(...)
		245	aio_nop $callback->()
		246
		247	$prev_pri = aioreq_pri [$pri]
		248	aioreq_nice $pri_adjust
		249
		250	IO::AIO::poll_wait
		251	IO::AIO::poll_cb
		252	IO::AIO::poll
		253	IO::AIO::flush
		254	IO::AIO::max_poll_reqs $nreqs
		255	IO::AIO::max_poll_time $seconds
		256	IO::AIO::min_parallel $nthreads
		257	IO::AIO::max_parallel $nthreads
		258	IO::AIO::max_idle $nthreads
		259	IO::AIO::max_outstanding $maxreqs
		260	IO::AIO::nreqs
		261	IO::AIO::nready
		262	IO::AIO::npending
		263
		264	IO::AIO::sendfile $ofh, $ifh, $offset, $count
		265	IO::AIO::fadvise $fh, $offset, $len, $advice
		266	IO::AIO::mlockall $flags
		267	IO::AIO::munlockall
210		268
211	=head2 AIO REQUEST FUNCTIONS	269	=head2 AIO REQUEST FUNCTIONS
212		270
213	All the C<aio_*> calls are more or less thin wrappers around the syscall	271	All the C<aio_*> calls are more or less thin wrappers around the syscall
214	with the same name (sans C<aio_>). The arguments are similar or identical,	272	with the same name (sans C<aio_>). The arguments are similar or identical,
215	and they all accept an additional (and optional) C<$callback> argument	273	and they all accept an additional (and optional) C<$callback> argument
216	which must be a code reference. This code reference will get called with	274	which must be a code reference. This code reference will get called with
217	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	275	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
218	perl, which usually delivers "false") as it's sole argument when the given	276	perl, which usually delivers "false") as its sole argument after the given
219	syscall has been executed asynchronously.	277	syscall has been executed asynchronously.
220		278
221	All functions expecting a filehandle keep a copy of the filehandle	279	All functions expecting a filehandle keep a copy of the filehandle
222	internally until the request has finished.	280	internally until the request has finished.
223		281
…		…
237	your pathnames to the locale (or other) encoding in effect in the user	295	your pathnames to the locale (or other) encoding in effect in the user
238	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	296	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
239	use something else to ensure your scalar has the correct contents.	297	use something else to ensure your scalar has the correct contents.
240		298
241	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	299	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
242	handles correctly wether it is set or not.	300	handles correctly whether it is set or not.
243		301
244	=over 4	302	=over 4
245		303
246	=item $prev_pri = aioreq_pri [$pri]	304	=item $prev_pri = aioreq_pri [$pri]
247		305
…		…
267	aio_read $_[0], ..., sub {	325	aio_read $_[0], ..., sub {
268	...	326	...
269	};	327	};
270	};	328	};
271		329
		330
272	=item aioreq_nice $pri_adjust	331	=item aioreq_nice $pri_adjust
273		332
274	Similar to C<aioreq_pri>, but subtracts the given value from the current	333	Similar to C<aioreq_pri>, but subtracts the given value from the current
275	priority, so the effect is cumulative.	334	priority, so the effect is cumulative.
		335
276		336
277	=item aio_open $pathname, $flags, $mode, $callback->($fh)	337	=item aio_open $pathname, $flags, $mode, $callback->($fh)
278		338
279	Asynchronously open or create a file and call the callback with a newly	339	Asynchronously open or create a file and call the callback with a newly
280	created filehandle for the file.	340	created filehandle for the file.
…		…
286	list. They are the same as used by C<sysopen>.	346	list. They are the same as used by C<sysopen>.
287		347
288	Likewise, C<$mode> specifies the mode of the newly created file, if it	348	Likewise, C<$mode> specifies the mode of the newly created file, if it
289	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	349	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
290	except that it is mandatory (i.e. use C<0> if you don't create new files,	350	except that it is mandatory (i.e. use C<0> if you don't create new files,
291	and C<0666> or C<0777> if you do).	351	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		352	by the umask in effect then the request is being executed, so better never
		353	change the umask.
292		354
293	Example:	355	Example:
294		356
295	aio_open "/etc/passwd", O_RDONLY, 0, sub {	357	aio_open "/etc/passwd", O_RDONLY, 0, sub {
296	if ($_[0]) {	358	if ($_[0]) {
…		…
299	} else {	361	} else {
300	die "open failed: $!\n";	362	die "open failed: $!\n";
301	}	363	}
302	};	364	};
303		365
		366
304	=item aio_close $fh, $callback->($status)	367	=item aio_close $fh, $callback->($status)
305		368
306	Asynchronously close a file and call the callback with the result	369	Asynchronously close a file and call the callback with the result
307	code. I<WARNING:> although accepted, you should not pass in a perl	370	code.
308	filehandle here, as perl will likely close the file descriptor another
309	time when the filehandle is destroyed. Normally, you can safely call perls
310	C<close> or just let filehandles go out of scope.
311		371
312	This is supposed to be a bug in the API, so that might change. It's	372	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
313	therefore best to avoid this function.	373	closing the file descriptor associated with the filehandle itself.
		374
		375	Therefore, C<aio_close> will not close the filehandle - instead it will
		376	use dup2 to overwrite the file descriptor with the write-end of a pipe
		377	(the pipe fd will be created on demand and will be cached).
		378
		379	Or in other words: the file descriptor will be closed, but it will not be
		380	free for reuse until the perl filehandle is closed.
		381
		382	=cut
314		383
315	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	384	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
316		385
317	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	386	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
318		387
319	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	388	Reads or writes C<$length> bytes from or to the specified C<$fh> and
320	into the scalar given by C<data> and offset C<dataoffset> and calls the	389	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
321	callback without the actual number of bytes read (or -1 on error, just	390	and calls the callback without the actual number of bytes read (or -1 on
322	like the syscall).	391	error, just like the syscall).
		392
		393	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		394	offset plus the actual number of bytes read.
		395
		396	If C<$offset> is undefined, then the current file descriptor offset will
		397	be used (and updated), otherwise the file descriptor offset will not be
		398	changed by these calls.
		399
		400	If C<$length> is undefined in C<aio_write>, use the remaining length of
		401	C<$data>.
		402
		403	If C<$dataoffset> is less than zero, it will be counted from the end of
		404	C<$data>.
323		405
324	The C<$data> scalar I<MUST NOT> be modified in any way while the request	406	The C<$data> scalar I<MUST NOT> be modified in any way while the request
325	is outstanding. Modifying it can result in segfaults or WW3 (if the	407	is outstanding. Modifying it can result in segfaults or World War III (if
326	necessary/optional hardware is installed).	408	the necessary/optional hardware is installed).
327		409
328	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	410	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
329	offset C<0> within the scalar:	411	offset C<0> within the scalar:
330		412
331	aio_read $fh, 7, 15, $buffer, 0, sub {	413	aio_read $fh, 7, 15, $buffer, 0, sub {
332	$_[0] > 0 or die "read error: $!";	414	$_[0] > 0 or die "read error: $!";
333	print "read $_[0] bytes: <$buffer>\n";	415	print "read $_[0] bytes: <$buffer>\n";
334	};	416	};
		417
335		418
336	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	419	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
337		420
338	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	421	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
339	reading at byte offset C<$in_offset>, and starts writing at the current	422	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
343		426
344	This call tries to make use of a native C<sendfile> syscall to provide	427	This call tries to make use of a native C<sendfile> syscall to provide
345	zero-copy operation. For this to work, C<$out_fh> should refer to a	428	zero-copy operation. For this to work, C<$out_fh> should refer to a
346	socket, and C<$in_fh> should refer to mmap'able file.	429	socket, and C<$in_fh> should refer to mmap'able file.
347		430
348	If the native sendfile call fails or is not implemented, it will be	431	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		432	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
349	emulated, so you can call C<aio_sendfile> on any type of filehandle	433	it will be emulated, so you can call C<aio_sendfile> on any type of
350	regardless of the limitations of the operating system.	434	filehandle regardless of the limitations of the operating system.
351		435
352	Please note, however, that C<aio_sendfile> can read more bytes from	436	Please note, however, that C<aio_sendfile> can read more bytes from
353	C<$in_fh> than are written, and there is no way to find out how many	437	C<$in_fh> than are written, and there is no way to find out how many
354	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	438	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
355	provides the number of bytes written to C<$out_fh>. Only if the result	439	provides the number of bytes written to C<$out_fh>. Only if the result
356	value equals C<$length> one can assume that C<$length> bytes have been	440	value equals C<$length> one can assume that C<$length> bytes have been
357	read.	441	read.
		442
358		443
359	=item aio_readahead $fh,$offset,$length, $callback->($retval)	444	=item aio_readahead $fh,$offset,$length, $callback->($retval)
360		445
361	C<aio_readahead> populates the page cache with data from a file so that	446	C<aio_readahead> populates the page cache with data from a file so that
362	subsequent reads from that file will not block on disk I/O. The C<$offset>	447	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
368	file. The current file offset of the file is left unchanged.	453	file. The current file offset of the file is left unchanged.
369		454
370	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	455	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
371	emulated by simply reading the data, which would have a similar effect.	456	emulated by simply reading the data, which would have a similar effect.
372		457
		458
373	=item aio_stat $fh_or_path, $callback->($status)	459	=item aio_stat $fh_or_path, $callback->($status)
374		460
375	=item aio_lstat $fh, $callback->($status)	461	=item aio_lstat $fh, $callback->($status)
376		462
377	Works like perl's C<stat> or C<lstat> in void context. The callback will	463	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
390	aio_stat "/etc/passwd", sub {	476	aio_stat "/etc/passwd", sub {
391	$_[0] and die "stat failed: $!";	477	$_[0] and die "stat failed: $!";
392	print "size is ", -s _, "\n";	478	print "size is ", -s _, "\n";
393	};	479	};
394		480
		481
		482	=item aio_statvfs $fh_or_path, $callback->($statvfs)
		483
		484	Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
		485	whether a file handle or path was passed.
		486
		487	On success, the callback is passed a hash reference with the following
		488	members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
		489	C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
		490	is passed.
		491
		492	The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
		493	C<ST_NOSUID>.
		494
		495	The following non-POSIX IO::AIO::ST_* flag masks are defined to
		496	their correct value when available, or to C<0> on systems that do
		497	not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
		498	C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
		499	C<ST_NODIRATIME> and C<ST_RELATIME>.
		500
		501	Example: stat C</wd> and dump out the data if successful.
		502
		503	aio_statvfs "/wd", sub {
		504	my $f = $_[0]
		505	or die "statvfs: $!";
		506
		507	use Data::Dumper;
		508	say Dumper $f;
		509	};
		510
		511	# result:
		512	{
		513	bsize => 1024,
		514	bfree => 4333064312,
		515	blocks => 10253828096,
		516	files => 2050765568,
		517	flag => 4096,
		518	favail => 2042092649,
		519	bavail => 4333064312,
		520	ffree => 2042092649,
		521	namemax => 255,
		522	frsize => 1024,
		523	fsid => 1810
		524	}
		525
		526
		527	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		528
		529	Works like perl's C<utime> function (including the special case of $atime
		530	and $mtime being undef). Fractional times are supported if the underlying
		531	syscalls support them.
		532
		533	When called with a pathname, uses utimes(2) if available, otherwise
		534	utime(2). If called on a file descriptor, uses futimes(2) if available,
		535	otherwise returns ENOSYS, so this is not portable.
		536
		537	Examples:
		538
		539	# set atime and mtime to current time (basically touch(1)):
		540	aio_utime "path", undef, undef;
		541	# set atime to current time and mtime to beginning of the epoch:
		542	aio_utime "path", time, undef; # undef==0
		543
		544
		545	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		546
		547	Works like perl's C<chown> function, except that C<undef> for either $uid
		548	or $gid is being interpreted as "do not change" (but -1 can also be used).
		549
		550	Examples:
		551
		552	# same as "chown root path" in the shell:
		553	aio_chown "path", 0, -1;
		554	# same as above:
		555	aio_chown "path", 0, undef;
		556
		557
		558	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		559
		560	Works like truncate(2) or ftruncate(2).
		561
		562
		563	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		564
		565	Works like perl's C<chmod> function.
		566
		567
395	=item aio_unlink $pathname, $callback->($status)	568	=item aio_unlink $pathname, $callback->($status)
396		569
397	Asynchronously unlink (delete) a file and call the callback with the	570	Asynchronously unlink (delete) a file and call the callback with the
398	result code.	571	result code.
399		572
		573
400	=item aio_mknod $path, $mode, $dev, $callback->($status)	574	=item aio_mknod $path, $mode, $dev, $callback->($status)
401		575
402	[EXPERIMENTAL]	576	[EXPERIMENTAL]
403		577
404	Asynchronously create a device node (or fifo). See mknod(2).	578	Asynchronously create a device node (or fifo). See mknod(2).
405		579
406	The only (POSIX-) portable way of calling this function is:	580	The only (POSIX-) portable way of calling this function is:
407		581
408	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	582	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		583
409		584
410	=item aio_link $srcpath, $dstpath, $callback->($status)	585	=item aio_link $srcpath, $dstpath, $callback->($status)
411		586
412	Asynchronously create a new link to the existing object at C<$srcpath> at	587	Asynchronously create a new link to the existing object at C<$srcpath> at
413	the path C<$dstpath> and call the callback with the result code.	588	the path C<$dstpath> and call the callback with the result code.
414		589
		590
415	=item aio_symlink $srcpath, $dstpath, $callback->($status)	591	=item aio_symlink $srcpath, $dstpath, $callback->($status)
416		592
417	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	593	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
418	the path C<$dstpath> and call the callback with the result code.	594	the path C<$dstpath> and call the callback with the result code.
419		595
		596
		597	=item aio_readlink $path, $callback->($link)
		598
		599	Asynchronously read the symlink specified by C<$path> and pass it to
		600	the callback. If an error occurs, nothing or undef gets passed to the
		601	callback.
		602
		603
420	=item aio_rename $srcpath, $dstpath, $callback->($status)	604	=item aio_rename $srcpath, $dstpath, $callback->($status)
421		605
422	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	606	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
423	rename(2) and call the callback with the result code.	607	rename(2) and call the callback with the result code.
424		608
		609
		610	=item aio_mkdir $pathname, $mode, $callback->($status)
		611
		612	Asynchronously mkdir (create) a directory and call the callback with
		613	the result code. C<$mode> will be modified by the umask at the time the
		614	request is executed, so do not change your umask.
		615
		616
425	=item aio_rmdir $pathname, $callback->($status)	617	=item aio_rmdir $pathname, $callback->($status)
426		618
427	Asynchronously rmdir (delete) a directory and call the callback with the	619	Asynchronously rmdir (delete) a directory and call the callback with the
428	result code.	620	result code.
		621
429		622
430	=item aio_readdir $pathname, $callback->($entries)	623	=item aio_readdir $pathname, $callback->($entries)
431		624
432	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	625	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
433	directory (i.e. opendir + readdir + closedir). The entries will not be	626	directory (i.e. opendir + readdir + closedir). The entries will not be
434	sorted, and will B<NOT> include the C<.> and C<..> entries.	627	sorted, and will B<NOT> include the C<.> and C<..> entries.
435		628
436	The callback a single argument which is either C<undef> or an array-ref	629	The callback is passed a single argument which is either C<undef> or an
437	with the filenames.	630	array-ref with the filenames.
		631
		632
		633	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		634
		635	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		636	behaviour and output format. In case of an error, C<$entries> will be
		637	C<undef>.
		638
		639	The flags are a combination of the following constants, ORed together (the
		640	flags will also be passed to the callback, possibly modified):
		641
		642	=over 4
		643
		644	=item IO::AIO::READDIR_DENTS
		645
		646	When this flag is off, then the callback gets an arrayref with of names
		647	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		648	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		649	entry in more detail.
		650
		651	C<$name> is the name of the entry.
		652
		653	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		654
		655	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		656	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		657	C<IO::AIO::DT_WHT>.
		658
		659	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		660	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		661	scalars are read-only: you can not modify them.
		662
		663	C<$inode> is the inode number (which might not be exact on systems with 64
		664	bit inode numbers and 32 bit perls). This field has unspecified content on
		665	systems that do not deliver the inode information.
		666
		667	=item IO::AIO::READDIR_DIRS_FIRST
		668
		669	When this flag is set, then the names will be returned in an order where
		670	likely directories come first. This is useful when you need to quickly
		671	find directories, or you want to find all directories while avoiding to
		672	stat() each entry.
		673
		674	If the system returns type information in readdir, then this is used
		675	to find directories directly. Otherwise, likely directories are files
		676	beginning with ".", or otherwise files with no dots, of which files with
		677	short names are tried first.
		678
		679	=item IO::AIO::READDIR_STAT_ORDER
		680
		681	When this flag is set, then the names will be returned in an order
		682	suitable for stat()'ing each one. That is, when you plan to stat()
		683	all files in the given directory, then the returned order will likely
		684	be fastest.
		685
		686	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		687	the likely dirs come first, resulting in a less optimal stat order.
		688
		689	=item IO::AIO::READDIR_FOUND_UNKNOWN
		690
		691	This flag should not be set when calling C<aio_readdirx>. Instead, it
		692	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		693	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		694	C<$type>'s are known, which can be used to speed up some algorithms.
		695
		696	=back
		697
		698
		699	=item aio_load $path, $data, $callback->($status)
		700
		701	This is a composite request that tries to fully load the given file into
		702	memory. Status is the same as with aio_read.
		703
		704	=cut
		705
		706	sub aio_load($$;$) {
		707	my ($path, undef, $cb) = @_;
		708	my $data = \$_[1];
		709
		710	my $pri = aioreq_pri;
		711	my $grp = aio_group $cb;
		712
		713	aioreq_pri $pri;
		714	add $grp aio_open $path, O_RDONLY, 0, sub {
		715	my $fh = shift
		716	or return $grp->result (-1);
		717
		718	aioreq_pri $pri;
		719	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		720	$grp->result ($_[0]);
		721	};
		722	};
		723
		724	$grp
		725	}
438		726
439	=item aio_copy $srcpath, $dstpath, $callback->($status)	727	=item aio_copy $srcpath, $dstpath, $callback->($status)
440		728
441	Try to copy the I<file> (directories not supported as either source or	729	Try to copy the I<file> (directories not supported as either source or
442	destination) from C<$srcpath> to C<$dstpath> and call the callback with	730	destination) from C<$srcpath> to C<$dstpath> and call the callback with
443	the C<0> (error) or C<-1> ok.	731	a status of C<0> (ok) or C<-1> (error, see C<$!>).
444		732
445	This is a composite request that it creates the destination file with	733	This is a composite request that creates the destination file with
446	mode 0200 and copies the contents of the source file into it using	734	mode 0200 and copies the contents of the source file into it using
447	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	735	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
448	uid/gid, in that order.	736	uid/gid, in that order.
449		737
450	If an error occurs, the partial destination file will be unlinked, if	738	If an error occurs, the partial destination file will be unlinked, if
…		…
460	my $grp = aio_group $cb;	748	my $grp = aio_group $cb;
461		749
462	aioreq_pri $pri;	750	aioreq_pri $pri;
463	add $grp aio_open $src, O_RDONLY, 0, sub {	751	add $grp aio_open $src, O_RDONLY, 0, sub {
464	if (my $src_fh = $_[0]) {	752	if (my $src_fh = $_[0]) {
465	my @stat = stat $src_fh;	753	my @stat = stat $src_fh; # hmm, might block over nfs?
466		754
467	aioreq_pri $pri;	755	aioreq_pri $pri;
468	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	756	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
469	if (my $dst_fh = $_[0]) {	757	if (my $dst_fh = $_[0]) {
470	aioreq_pri $pri;	758	aioreq_pri $pri;
471	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	759	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
472	if ($_[0] == $stat[7]) {	760	if ($_[0] == $stat[7]) {
473	$grp->result (0);	761	$grp->result (0);
474	close $src_fh;	762	close $src_fh;
475		763
476	# those should not normally block. should. should.	764	my $ch = sub {
		765	aioreq_pri $pri;
		766	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		767	aioreq_pri $pri;
		768	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		769	aioreq_pri $pri;
		770	add $grp aio_close $dst_fh;
		771	}
		772	};
		773	};
		774
		775	aioreq_pri $pri;
		776	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		777	if ($_[0] < 0 && $! == ENOSYS) {
		778	aioreq_pri $pri;
477	utime $stat[8], $stat[9], $dst;	779	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
478	chmod $stat[2] & 07777, $dst_fh;	780	} else {
479	chown $stat[4], $stat[5], $dst_fh;	781	$ch->();
		782	}
480	close $dst_fh;	783	};
481	} else {	784	} else {
482	$grp->result (-1);	785	$grp->result (-1);
483	close $src_fh;	786	close $src_fh;
484	close $dst_fh;	787	close $dst_fh;
485		788
…		…
502		805
503	=item aio_move $srcpath, $dstpath, $callback->($status)	806	=item aio_move $srcpath, $dstpath, $callback->($status)
504		807
505	Try to move the I<file> (directories not supported as either source or	808	Try to move the I<file> (directories not supported as either source or
506	destination) from C<$srcpath> to C<$dstpath> and call the callback with	809	destination) from C<$srcpath> to C<$dstpath> and call the callback with
507	the C<0> (error) or C<-1> ok.	810	a status of C<0> (ok) or C<-1> (error, see C<$!>).
508		811
509	This is a composite request that tries to rename(2) the file first. If	812	This is a composite request that tries to rename(2) the file first; if
510	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	813	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
511	that is successful, unlinking the C<$srcpath>.	814	that is successful, unlinks the C<$srcpath>.
512		815
513	=cut	816	=cut
514		817
515	sub aio_move($$;$) {	818	sub aio_move($$;$) {
516	my ($src, $dst, $cb) = @_;	819	my ($src, $dst, $cb) = @_;
…		…
563		866
564	Implementation notes.	867	Implementation notes.
565		868
566	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	869	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
567		870
		871	If readdir returns file type information, then this is used directly to
		872	find directories.
		873
568	After reading the directory, the modification time, size etc. of the	874	Otherwise, after reading the directory, the modification time, size etc.
569	directory before and after the readdir is checked, and if they match (and	875	of the directory before and after the readdir is checked, and if they
570	isn't the current time), the link count will be used to decide how many	876	match (and isn't the current time), the link count will be used to decide
571	entries are directories (if >= 2). Otherwise, no knowledge of the number	877	how many entries are directories (if >= 2). Otherwise, no knowledge of the
572	of subdirectories will be assumed.	878	number of subdirectories will be assumed.
573		879
574	Then entries will be sorted into likely directories (everything without	880	Then entries will be sorted into likely directories a non-initial dot
575	a non-initial dot currently) and likely non-directories (everything	881	currently) and likely non-directories (see C<aio_readdirx>). Then every
576	else). Then every entry plus an appended C</.> will be C<stat>'ed,	882	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
577	likely directories first. If that succeeds, it assumes that the entry	883	in order of their inode numbers. If that succeeds, it assumes that the
578	is a directory or a symlink to directory (which will be checked	884	entry is a directory or a symlink to directory (which will be checked
579	seperately). This is often faster than stat'ing the entry itself because	885	seperately). This is often faster than stat'ing the entry itself because
580	filesystems might detect the type of the entry without reading the inode	886	filesystems might detect the type of the entry without reading the inode
581	data (e.g. ext2fs filetype feature).	887	data (e.g. ext2fs filetype feature), even on systems that cannot return
		888	the filetype information on readdir.
582		889
583	If the known number of directories (link count - 2) has been reached, the	890	If the known number of directories (link count - 2) has been reached, the
584	rest of the entries is assumed to be non-directories.	891	rest of the entries is assumed to be non-directories.
585		892
586	This only works with certainty on POSIX (= UNIX) filesystems, which	893	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
590	as those tend to return 0 or 1 as link counts, which disables the	897	as those tend to return 0 or 1 as link counts, which disables the
591	directory counting heuristic.	898	directory counting heuristic.
592		899
593	=cut	900	=cut
594		901
595	sub aio_scandir($$$) {	902	sub aio_scandir($$;$) {
596	my ($path, $maxreq, $cb) = @_;	903	my ($path, $maxreq, $cb) = @_;
597		904
598	my $pri = aioreq_pri;	905	my $pri = aioreq_pri;
599		906
600	my $grp = aio_group $cb;	907	my $grp = aio_group $cb;
…		…
608	my $now = time;	915	my $now = time;
609	my $hash1 = join ":", (stat _)[0,1,3,7,9];	916	my $hash1 = join ":", (stat _)[0,1,3,7,9];
610		917
611	# read the directory entries	918	# read the directory entries
612	aioreq_pri $pri;	919	aioreq_pri $pri;
613	add $grp aio_readdir $path, sub {	920	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
614	my $entries = shift	921	my $entries = shift
615	or return $grp->result ();	922	or return $grp->result ();
616		923
617	# stat the dir another time	924	# stat the dir another time
618	aioreq_pri $pri;	925	aioreq_pri $pri;
…		…
624	# take the slow route if anything looks fishy	931	# take the slow route if anything looks fishy
625	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	932	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
626	$ndirs = -1;	933	$ndirs = -1;
627	} else {	934	} else {
628	# if nlink == 2, we are finished	935	# if nlink == 2, we are finished
629	# on non-posix-fs's, we rely on nlink < 2	936	# for non-posix-fs's, we rely on nlink < 2
630	$ndirs = (stat _)[3] - 2	937	$ndirs = (stat _)[3] - 2
631	or return $grp->result ([], $entries);	938	or return $grp->result ([], $entries);
632	}	939	}
633		940
634	# sort into likely dirs and likely nondirs
635	# dirs == files without ".", short entries first
636	$entries = [map $_->[0],
637	sort { $b->[1] cmp $a->[1] }
638	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
639	@$entries];
640
641	my (@dirs, @nondirs);	941	my (@dirs, @nondirs);
642		942
643	my $statgrp = add $grp aio_group sub {	943	my $statgrp = add $grp aio_group sub {
644	$grp->result (\@dirs, \@nondirs);	944	$grp->result (\@dirs, \@nondirs);
645	};	945	};
646		946
647	limit $statgrp $maxreq;	947	limit $statgrp $maxreq;
648	feed $statgrp sub {	948	feed $statgrp sub {
649	return unless @$entries;	949	return unless @$entries;
650	my $entry = pop @$entries;	950	my $entry = shift @$entries;
651		951
652	aioreq_pri $pri;	952	aioreq_pri $pri;
653	add $statgrp aio_stat "$path/$entry/.", sub {	953	add $statgrp aio_stat "$path/$entry/.", sub {
654	if ($_[0] < 0) {	954	if ($_[0] < 0) {
655	push @nondirs, $entry;	955	push @nondirs, $entry;
…		…
676	};	976	};
677		977
678	$grp	978	$grp
679	}	979	}
680		980
		981	=item aio_rmtree $path, $callback->($status)
		982
		983	Delete a directory tree starting (and including) C<$path>, return the
		984	status of the final C<rmdir> only. This is a composite request that
		985	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		986	everything else.
		987
		988	=cut
		989
		990	sub aio_rmtree;
		991	sub aio_rmtree($;$) {
		992	my ($path, $cb) = @_;
		993
		994	my $pri = aioreq_pri;
		995	my $grp = aio_group $cb;
		996
		997	aioreq_pri $pri;
		998	add $grp aio_scandir $path, 0, sub {
		999	my ($dirs, $nondirs) = @_;
		1000
		1001	my $dirgrp = aio_group sub {
		1002	add $grp aio_rmdir $path, sub {
		1003	$grp->result ($_[0]);
		1004	};
		1005	};
		1006
		1007	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		1008	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		1009
		1010	add $grp $dirgrp;
		1011	};
		1012
		1013	$grp
		1014	}
		1015
		1016	=item aio_sync $callback->($status)
		1017
		1018	Asynchronously call sync and call the callback when finished.
		1019
681	=item aio_fsync $fh, $callback->($status)	1020	=item aio_fsync $fh, $callback->($status)
682		1021
683	Asynchronously call fsync on the given filehandle and call the callback	1022	Asynchronously call fsync on the given filehandle and call the callback
684	with the fsync result code.	1023	with the fsync result code.
685		1024
…		…
688	Asynchronously call fdatasync on the given filehandle and call the	1027	Asynchronously call fdatasync on the given filehandle and call the
689	callback with the fdatasync result code.	1028	callback with the fdatasync result code.
690		1029
691	If this call isn't available because your OS lacks it or it couldn't be	1030	If this call isn't available because your OS lacks it or it couldn't be
692	detected, it will be emulated by calling C<fsync> instead.	1031	detected, it will be emulated by calling C<fsync> instead.
		1032
		1033	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		1034
		1035	Sync the data portion of the file specified by C<$offset> and C<$length>
		1036	to disk (but NOT the metadata), by calling the Linux-specific
		1037	sync_file_range call. If sync_file_range is not available or it returns
		1038	ENOSYS, then fdatasync or fsync is being substituted.
		1039
		1040	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		1041	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		1042	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		1043	manpage for details.
		1044
		1045	=item aio_pathsync $path, $callback->($status)
		1046
		1047	This request tries to open, fsync and close the given path. This is a
		1048	composite request intended to sync directories after directory operations
		1049	(E.g. rename). This might not work on all operating systems or have any
		1050	specific effect, but usually it makes sure that directory changes get
		1051	written to disc. It works for anything that can be opened for read-only,
		1052	not just directories.
		1053
		1054	Future versions of this function might fall back to other methods when
		1055	C<fsync> on the directory fails (such as calling C<sync>).
		1056
		1057	Passes C<0> when everything went ok, and C<-1> on error.
		1058
		1059	=cut
		1060
		1061	sub aio_pathsync($;$) {
		1062	my ($path, $cb) = @_;
		1063
		1064	my $pri = aioreq_pri;
		1065	my $grp = aio_group $cb;
		1066
		1067	aioreq_pri $pri;
		1068	add $grp aio_open $path, O_RDONLY, 0, sub {
		1069	my ($fh) = @_;
		1070	if ($fh) {
		1071	aioreq_pri $pri;
		1072	add $grp aio_fsync $fh, sub {
		1073	$grp->result ($_[0]);
		1074
		1075	aioreq_pri $pri;
		1076	add $grp aio_close $fh;
		1077	};
		1078	} else {
		1079	$grp->result (-1);
		1080	}
		1081	};
		1082
		1083	$grp
		1084	}
		1085
		1086	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1087
		1088	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		1089	scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note
		1090	that the scalar must only be modified in-place while an aio operation is
		1091	pending on it).
		1092
		1093	It calls the C<msync> function of your OS, if available, with the memory
		1094	area starting at C<$offset> in the string and ending C<$length> bytes
		1095	later. If C<$length> is negative, counts from the end, and if C<$length>
		1096	is C<undef>, then it goes till the end of the string. The flags can be
		1097	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1098	C<IO::AIO::MS_SYNC>.
		1099
		1100	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1101
		1102	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1103	scalars.
		1104
		1105	It touches (reads or writes) all memory pages in the specified
		1106	range inside the scalar. All caveats and parameters are the same
		1107	as for C<aio_msync>, above, except for flags, which must be either
		1108	C<0> (which reads all pages and ensures they are instantiated) or
		1109	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1110	writing an octet from it, which dirties the page).
693		1111
694	=item aio_group $callback->(...)	1112	=item aio_group $callback->(...)
695		1113
696	This is a very special aio request: Instead of doing something, it is a	1114	This is a very special aio request: Instead of doing something, it is a
697	container for other aio requests, which is useful if you want to bundle	1115	container for other aio requests, which is useful if you want to bundle
…		…
747	=item cancel $req	1165	=item cancel $req
748		1166
749	Cancels the request, if possible. Has the effect of skipping execution	1167	Cancels the request, if possible. Has the effect of skipping execution
750	when entering the B<execute> state and skipping calling the callback when	1168	when entering the B<execute> state and skipping calling the callback when
751	entering the the B<result> state, but will leave the request otherwise	1169	entering the the B<result> state, but will leave the request otherwise
752	untouched. That means that requests that currently execute will not be	1170	untouched (with the exception of readdir). That means that requests that
753	stopped and resources held by the request will not be freed prematurely.	1171	currently execute will not be stopped and resources held by the request
		1172	will not be freed prematurely.
754		1173
755	=item cb $req $callback->(...)	1174	=item cb $req $callback->(...)
756		1175
757	Replace (or simply set) the callback registered to the request.	1176	Replace (or simply set) the callback registered to the request.
758		1177
…		…
809	Their lifetime, simplified, looks like this: when they are empty, they	1228	Their lifetime, simplified, looks like this: when they are empty, they
810	will finish very quickly. If they contain only requests that are in the	1229	will finish very quickly. If they contain only requests that are in the
811	C<done> state, they will also finish. Otherwise they will continue to	1230	C<done> state, they will also finish. Otherwise they will continue to
812	exist.	1231	exist.
813		1232
814	That means after creating a group you have some time to add requests. And	1233	That means after creating a group you have some time to add requests
815	in the callbacks of those requests, you can add further requests to the	1234	(precisely before the callback has been invoked, which is only done within
816	group. And only when all those requests have finished will the the group	1235	the C<poll_cb>). And in the callbacks of those requests, you can add
817	itself finish.	1236	further requests to the group. And only when all those requests have
		1237	finished will the the group itself finish.
818		1238
819	=over 4	1239	=over 4
820		1240
821	=item add $grp ...	1241	=item add $grp ...
822		1242
…		…
831	=item $grp->cancel_subs	1251	=item $grp->cancel_subs
832		1252
833	Cancel all subrequests and clears any feeder, but not the group request	1253	Cancel all subrequests and clears any feeder, but not the group request
834	itself. Useful when you queued a lot of events but got a result early.	1254	itself. Useful when you queued a lot of events but got a result early.
835		1255
		1256	The group request will finish normally (you cannot add requests to the
		1257	group).
		1258
836	=item $grp->result (...)	1259	=item $grp->result (...)
837		1260
838	Set the result value(s) that will be passed to the group callback when all	1261	Set the result value(s) that will be passed to the group callback when all
839	subrequests have finished and set thre groups errno to the current value	1262	subrequests have finished and set the groups errno to the current value
840	of errno (just like calling C<errno> without an error number). By default,	1263	of errno (just like calling C<errno> without an error number). By default,
841	no argument will be passed and errno is zero.	1264	no argument will be passed and errno is zero.
842		1265
843	=item $grp->errno ([$errno])	1266	=item $grp->errno ([$errno])
844		1267
…		…
855	=item feed $grp $callback->($grp)	1278	=item feed $grp $callback->($grp)
856		1279
857	Sets a feeder/generator on this group: every group can have an attached	1280	Sets a feeder/generator on this group: every group can have an attached
858	generator that generates requests if idle. The idea behind this is that,	1281	generator that generates requests if idle. The idea behind this is that,
859	although you could just queue as many requests as you want in a group,	1282	although you could just queue as many requests as you want in a group,
860	this might starve other requests for a potentially long time. For	1283	this might starve other requests for a potentially long time. For example,
861	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1284	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
862	requests, delaying any later requests for a long time.	1285	delaying any later requests for a long time.
863		1286
864	To avoid this, and allow incremental generation of requests, you can	1287	To avoid this, and allow incremental generation of requests, you can
865	instead a group and set a feeder on it that generates those requests. The	1288	instead a group and set a feeder on it that generates those requests. The
866	feed callback will be called whenever there are few enough (see C<limit>,	1289	feed callback will be called whenever there are few enough (see C<limit>,
867	below) requests active in the group itself and is expected to queue more	1290	below) requests active in the group itself and is expected to queue more
…		…
871	not impose any limits).	1294	not impose any limits).
872		1295
873	If the feed does not queue more requests when called, it will be	1296	If the feed does not queue more requests when called, it will be
874	automatically removed from the group.	1297	automatically removed from the group.
875		1298
876	If the feed limit is C<0>, it will be set to C<2> automatically.	1299	If the feed limit is C<0> when this method is called, it will be set to
		1300	C<2> automatically.
877		1301
878	Example:	1302	Example:
879		1303
880	# stat all files in @files, but only ever use four aio requests concurrently:	1304	# stat all files in @files, but only ever use four aio requests concurrently:
881		1305
…		…
893	Sets the feeder limit for the group: The feeder will be called whenever	1317	Sets the feeder limit for the group: The feeder will be called whenever
894	the group contains less than this many requests.	1318	the group contains less than this many requests.
895		1319
896	Setting the limit to C<0> will pause the feeding process.	1320	Setting the limit to C<0> will pause the feeding process.
897		1321
		1322	The default value for the limit is C<0>, but note that setting a feeder
		1323	automatically bumps it up to C<2>.
		1324
898	=back	1325	=back
899		1326
900	=head2 SUPPORT FUNCTIONS	1327	=head2 SUPPORT FUNCTIONS
901		1328
902	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1329	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
904	=over 4	1331	=over 4
905		1332
906	=item $fileno = IO::AIO::poll_fileno	1333	=item $fileno = IO::AIO::poll_fileno
907		1334
908	Return the I<request result pipe file descriptor>. This filehandle must be	1335	Return the I<request result pipe file descriptor>. This filehandle must be
909	polled for reading by some mechanism outside this module (e.g. Event or	1336	polled for reading by some mechanism outside this module (e.g. EV, Glib,
910	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1337	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
911	to call C<poll_cb> to check the results.	1338	you have to call C<poll_cb> to check the results.
912		1339
913	See C<poll_cb> for an example.	1340	See C<poll_cb> for an example.
914		1341
915	=item IO::AIO::poll_cb	1342	=item IO::AIO::poll_cb
916		1343
917	Process some outstanding events on the result pipe. You have to call this	1344	Process some outstanding events on the result pipe. You have to call this
918	regularly. Returns the number of events processed. Returns immediately	1345	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1346	returned earlier for whatever reason. Returns immediately when no events
919	when no events are outstanding. The amount of events processed depends on	1347	are outstanding. The amount of events processed depends on the settings of
920	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1348	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
921		1349
922	If not all requests were processed for whatever reason, the filehandle	1350	If not all requests were processed for whatever reason, the filehandle
923	will still be ready when C<poll_cb> returns.	1351	will still be ready when C<poll_cb> returns, so normally you don't have to
		1352	do anything special to have it called later.
924		1353
925	Example: Install an Event watcher that automatically calls	1354	Example: Install an Event watcher that automatically calls
926	IO::AIO::poll_cb with high priority:	1355	IO::AIO::poll_cb with high priority (more examples can be found in the
		1356	SYNOPSIS section, at the top of this document):
927		1357
928	Event->io (fd => IO::AIO::poll_fileno,	1358	Event->io (fd => IO::AIO::poll_fileno,
929	poll => 'r', async => 1,	1359	poll => 'r', async => 1,
930	cb => \&IO::AIO::poll_cb);	1360	cb => \&IO::AIO::poll_cb);
		1361
		1362	=item IO::AIO::poll_wait
		1363
		1364	If there are any outstanding requests and none of them in the result
		1365	phase, wait till the result filehandle becomes ready for reading (simply
		1366	does a C<select> on the filehandle. This is useful if you want to
		1367	synchronously wait for some requests to finish).
		1368
		1369	See C<nreqs> for an example.
		1370
		1371	=item IO::AIO::poll
		1372
		1373	Waits until some requests have been handled.
		1374
		1375	Returns the number of requests processed, but is otherwise strictly
		1376	equivalent to:
		1377
		1378	IO::AIO::poll_wait, IO::AIO::poll_cb
		1379
		1380	=item IO::AIO::flush
		1381
		1382	Wait till all outstanding AIO requests have been handled.
		1383
		1384	Strictly equivalent to:
		1385
		1386	IO::AIO::poll_wait, IO::AIO::poll_cb
		1387	while IO::AIO::nreqs;
931		1388
932	=item IO::AIO::max_poll_reqs $nreqs	1389	=item IO::AIO::max_poll_reqs $nreqs
933		1390
934	=item IO::AIO::max_poll_time $seconds	1391	=item IO::AIO::max_poll_time $seconds
935		1392
…		…
937	that are being processed by C<IO::AIO::poll_cb> in one call, respectively	1394	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
938	the maximum amount of time (default C<0>, meaning infinity) spent in	1395	the maximum amount of time (default C<0>, meaning infinity) spent in
939	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount	1396	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
940	of time C<poll_cb> is allowed to use).	1397	of time C<poll_cb> is allowed to use).
941		1398
		1399	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1400	syscall per request processed, which is not normally a problem unless your
		1401	callbacks are really really fast or your OS is really really slow (I am
		1402	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1403
942	Setting these is useful if you want to ensure some level of	1404	Setting these is useful if you want to ensure some level of
943	interactiveness when perl is not fast enough to process all requests in	1405	interactiveness when perl is not fast enough to process all requests in
944	time.	1406	time.
945		1407
946	For interactive programs, values such as C<0.01> to C<0.1> should be fine.	1408	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
947		1409
948	Example: Install an Event watcher that automatically calls	1410	Example: Install an Event watcher that automatically calls
949	IO::AIO::poll_some with low priority, to ensure that other parts of the	1411	IO::AIO::poll_cb with low priority, to ensure that other parts of the
950	program get the CPU sometimes even under high AIO load.	1412	program get the CPU sometimes even under high AIO load.
951		1413
952	# try not to spend much more than 0.1s in poll_cb	1414	# try not to spend much more than 0.1s in poll_cb
953	IO::AIO::max_poll_time 0.1;	1415	IO::AIO::max_poll_time 0.1;
954		1416
955	# use a low priority so other tasks have priority	1417	# use a low priority so other tasks have priority
956	Event->io (fd => IO::AIO::poll_fileno,	1418	Event->io (fd => IO::AIO::poll_fileno,
957	poll => 'r', nice => 1,	1419	poll => 'r', nice => 1,
958	cb => &IO::AIO::poll_cb);	1420	cb => &IO::AIO::poll_cb);
959		1421
960	=item IO::AIO::poll_wait	1422	=back
961
962	Wait till the result filehandle becomes ready for reading (simply does a
963	C<select> on the filehandle. This is useful if you want to synchronously
964	wait for some requests to finish).
965
966	See C<nreqs> for an example.
967
968	=item IO::AIO::poll
969
970	Waits until some requests have been handled.
971
972	Strictly equivalent to:
973
974	IO::AIO::poll_wait, IO::AIO::poll_cb
975	if IO::AIO::nreqs;
976
977	=item IO::AIO::flush
978
979	Wait till all outstanding AIO requests have been handled.
980
981	Strictly equivalent to:
982
983	IO::AIO::poll_wait, IO::AIO::poll_cb
984	while IO::AIO::nreqs;
985		1423
986	=head3 CONTROLLING THE NUMBER OF THREADS	1424	=head3 CONTROLLING THE NUMBER OF THREADS
		1425
		1426	=over
987		1427
988	=item IO::AIO::min_parallel $nthreads	1428	=item IO::AIO::min_parallel $nthreads
989		1429
990	Set the minimum number of AIO threads to C<$nthreads>. The current	1430	Set the minimum number of AIO threads to C<$nthreads>. The current
991	default is C<8>, which means eight asynchronous operations can execute	1431	default is C<8>, which means eight asynchronous operations can execute
…		…
1032		1472
1033	The default is probably ok in most situations, especially if thread	1473	The default is probably ok in most situations, especially if thread
1034	creation is fast. If thread creation is very slow on your system you might	1474	creation is fast. If thread creation is very slow on your system you might
1035	want to use larger values.	1475	want to use larger values.
1036		1476
1037	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1477	=item IO::AIO::max_outstanding $maxreqs
1038		1478
1039	This is a very bad function to use in interactive programs because it	1479	This is a very bad function to use in interactive programs because it
1040	blocks, and a bad way to reduce concurrency because it is inexact: Better	1480	blocks, and a bad way to reduce concurrency because it is inexact: Better
1041	use an C<aio_group> together with a feed callback.	1481	use an C<aio_group> together with a feed callback.
1042		1482
1043	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1483	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1044	to queue up more than this number of requests, the next call to the	1484	do queue up more than this number of requests, the next call to the
1045	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1485	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1046	function will block until the limit is no longer exceeded.	1486	function will block until the limit is no longer exceeded.
1047		1487
1048	The default value is very large, so there is no practical limit on the	1488	The default value is very large, so there is no practical limit on the
1049	number of outstanding requests.	1489	number of outstanding requests.
1050		1490
1051	You can still queue as many requests as you want. Therefore,	1491	You can still queue as many requests as you want. Therefore,
1052	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1492	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1053	as a stop gap to shield against fatal memory overflow (with large values).	1493	as a stop gap to shield against fatal memory overflow (with large values).
1054		1494
		1495	=back
		1496
1055	=head3 STATISTICAL INFORMATION	1497	=head3 STATISTICAL INFORMATION
		1498
		1499	=over
1056		1500
1057	=item IO::AIO::nreqs	1501	=item IO::AIO::nreqs
1058		1502
1059	Returns the number of requests currently in the ready, execute or pending	1503	Returns the number of requests currently in the ready, execute or pending
1060	states (i.e. for which their callback has not been invoked yet).	1504	states (i.e. for which their callback has not been invoked yet).
…		…
1074	Returns the number of requests currently in the pending state (executed,	1518	Returns the number of requests currently in the pending state (executed,
1075	but not yet processed by poll_cb).	1519	but not yet processed by poll_cb).
1076		1520
1077	=back	1521	=back
1078		1522
		1523	=head3 MISCELLANEOUS FUNCTIONS
		1524
		1525	IO::AIO implements some functions that might be useful, but are not
		1526	asynchronous.
		1527
		1528	=over 4
		1529
		1530	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1531
		1532	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1533	but is blocking (this makes most sense if you know the input data is
		1534	likely cached already and the output filehandle is set to non-blocking
		1535	operations).
		1536
		1537	Returns the number of bytes copied, or C<-1> on error.
		1538
		1539	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1540
		1541	Simply calls the C<posix_fadvise> function (see it's
		1542	manpage for details). The following advice constants are
		1543	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1544	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1545	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1546
		1547	On systems that do not implement C<posix_fadvise>, this function returns
		1548	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1549
		1550	=item IO::AIO::mlockall $flags
		1551
		1552	Calls the C<mlockall> function with the given C<$flags> (a combination of
		1553	C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL__FUTURE>).
		1554
		1555	On systems that do not implement C<mlockall>, this function returns
		1556	ENOSYS, otherwise the return value of C<mlockall>.
		1557
		1558	=item IO::AIO::munlockall
		1559
		1560	Calls the C<munlockall> function.
		1561
		1562	On systems that do not implement C<munlockall>, this function returns
		1563	ENOSYS, otherwise the return value of C<munlockall>.
		1564
		1565	=back
		1566
1079	=cut	1567	=cut
1080		1568
1081	# support function to convert a fd into a perl filehandle
1082	sub _fd2fh {
1083	return undef if $_[0] < 0;
1084
1085	# try to generate nice filehandles
1086	my $sym = "IO::AIO::fd#$_[0]";
1087	local *$sym;
1088
1089	open *$sym, "+<&=$_[0]" # usually works under any unix
1090	or open *$sym, "<&=$_[0]" # cygwin needs this
1091	or open *$sym, ">&=$_[0]" # or this
1092	or return undef;
1093
1094	*$sym
1095	}
1096
1097	min_parallel 8;	1569	min_parallel 8;
1098		1570
1099	END {	1571	END { flush }
1100	min_parallel 1;
1101	flush;
1102	};
1103		1572
1104	1;	1573	1;
		1574
		1575	=head1 EVENT LOOP INTEGRATION
		1576
		1577	It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
		1578	automatically into many event loops:
		1579
		1580	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		1581	use AnyEvent::AIO;
		1582
		1583	You can also integrate IO::AIO manually into many event loops, here are
		1584	some examples of how to do this:
		1585
		1586	# EV integration
		1587	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
		1588
		1589	# Event integration
		1590	Event->io (fd => IO::AIO::poll_fileno,
		1591	poll => 'r',
		1592	cb => \&IO::AIO::poll_cb);
		1593
		1594	# Glib/Gtk2 integration
		1595	add_watch Glib::IO IO::AIO::poll_fileno,
		1596	in => sub { IO::AIO::poll_cb; 1 };
		1597
		1598	# Tk integration
		1599	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
		1600	readable => \&IO::AIO::poll_cb);
		1601
		1602	# Danga::Socket integration
		1603	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
		1604	\&IO::AIO::poll_cb);
1105		1605
1106	=head2 FORK BEHAVIOUR	1606	=head2 FORK BEHAVIOUR
1107		1607
1108	This module should do "the right thing" when the process using it forks:	1608	This module should do "the right thing" when the process using it forks:
1109		1609
…		…
1127	bytes of memory. In addition, stat requests need a stat buffer (possibly	1627	bytes of memory. In addition, stat requests need a stat buffer (possibly
1128	a few hundred bytes), readdir requires a result buffer and so on. Perl	1628	a few hundred bytes), readdir requires a result buffer and so on. Perl
1129	scalars and other data passed into aio requests will also be locked and	1629	scalars and other data passed into aio requests will also be locked and
1130	will consume memory till the request has entered the done state.	1630	will consume memory till the request has entered the done state.
1131		1631
1132	This is now awfully much, so queuing lots of requests is not usually a	1632	This is not awfully much, so queuing lots of requests is not usually a
1133	problem.	1633	problem.
1134		1634
1135	Per-thread usage:	1635	Per-thread usage:
1136		1636
1137	In the execution phase, some aio requests require more memory for	1637	In the execution phase, some aio requests require more memory for
…		…
1142		1642
1143	Known bugs will be fixed in the next release.	1643	Known bugs will be fixed in the next release.
1144		1644
1145	=head1 SEE ALSO	1645	=head1 SEE ALSO
1146		1646
1147	L<Coro::AIO>.	1647	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1648	more natural syntax.
1148		1649
1149	=head1 AUTHOR	1650	=head1 AUTHOR
1150		1651
1151	Marc Lehmann <schmorp@schmorp.de>	1652	Marc Lehmann <schmorp@schmorp.de>
1152	http://home.schmorp.de/	1653	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.87 by root, Sun Oct 29 00:52:02 2006 UTC vs. Revision 1.175 by root, Sun Jan 10 20:37:33 2010 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.87 by root, Sun Oct 29 00:52:02 2006 UTC vs.
Revision 1.175 by root, Sun Jan 10 20:37:33 2010 UTC