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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.100 by root, Sun Jan 7 21:36:58 2007 UTC vs.
Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC

…		…
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 (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		32	use AnyEvent::AIO;
		33
31	# AnyEvent integration	34	# EV integration
32	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";	35	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
33	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34		36
35	# Event integration	37	# Event integration
36	Event->io (fd => IO::AIO::poll_fileno,	38	Event->io (fd => IO::AIO::poll_fileno,
37	poll => 'r',	39	poll => 'r',
38	cb => \&IO::AIO::poll_cb);	40	cb => \&IO::AIO::poll_cb);
…		…
50	\&IO::AIO::poll_cb);	52	\&IO::AIO::poll_cb);
51		53
52	=head1 DESCRIPTION	54	=head1 DESCRIPTION
53		55
54	This module implements asynchronous I/O using whatever means your	56	This module implements asynchronous I/O using whatever means your
55	operating system supports.	57	operating system supports. It is implemented as an interface to C<libeio>
		58	(L<http://software.schmorp.de/pkg/libeio.html>).
56		59
57	Asynchronous means that operations that can normally block your program	60	Asynchronous means that operations that can normally block your program
58	(e.g. reading from disk) will be done asynchronously: the operation	61	(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	62	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	63	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	65	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	66	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	67	on a RAID volume or over NFS when you do a number of stat operations
65	concurrently.	68	concurrently.
66		69
67	While most of this works on all types of file descriptors (for example	70	While most of this works on all types of file descriptors (for
68	sockets), using these functions on file descriptors that support	71	example sockets), using these functions on file descriptors that
69	nonblocking operation (again, sockets, pipes etc.) is very inefficient or	72	support nonblocking operation (again, sockets, pipes etc.) is
70	might not work (aio_read fails on sockets/pipes/fifos). Use an event loop	73	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	74	module): IO::AIO will naturally fit into such an event loop itself.
72	into such an event loop itself.
73		75
74	In this version, a number of threads are started that execute your	76	In this version, a number of threads are started that execute your
75	requests and signal their completion. You don't need thread support	77	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	78	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	79	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	81	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	82	files currently, for example), and they would only support aio_read and
81	aio_write, so the remaining functionality would have to be implemented	83	aio_write, so the remaining functionality would have to be implemented
82	using threads anyway.	84	using threads anyway.
83		85
84	Although the module will work with in the presence of other (Perl-)	86	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	87	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	88	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.	89	call C<poll_cb> (or other C<aio_> functions) recursively.
88		90
89	=head2 EXAMPLE	91	=head2 EXAMPLE
90		92
91	This is a simple example that uses the Event module and loads	93	This is a simple example that uses the EV module and loads
92	F</etc/passwd> asynchronously:	94	F</etc/passwd> asynchronously:
93		95
94	use Fcntl;	96	use Fcntl;
95	use Event;	97	use EV;
96	use IO::AIO;	98	use IO::AIO;
97		99
98	# register the IO::AIO callback with Event	100	# register the IO::AIO callback with EV
99	Event->io (fd => IO::AIO::poll_fileno,	101	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		102
103	# queue the request to open /etc/passwd	103	# queue the request to open /etc/passwd
104	aio_open "/etc/passwd", O_RDONLY, 0, sub {	104	aio_open "/etc/passwd", O_RDONLY, 0, sub {
105	my $fh = shift	105	my $fh = shift
106	or die "error while opening: $!";	106	or die "error while opening: $!";
…		…
118		118
119	# file contents now in $contents	119	# file contents now in $contents
120	print $contents;	120	print $contents;
121		121
122	# exit event loop and program	122	# exit event loop and program
123	Event::unloop;	123	EV::unloop;
124	};	124	};
125	};	125	};
126		126
127	# possibly queue up other requests, or open GUI windows,	127	# possibly queue up other requests, or open GUI windows,
128	# check for sockets etc. etc.	128	# check for sockets etc. etc.
129		129
130	# process events as long as there are some:	130	# process events as long as there are some:
131	Event::loop;	131	EV::loop;
132		132
133	=head1 REQUEST ANATOMY AND LIFETIME	133	=head1 REQUEST ANATOMY AND LIFETIME
134		134
135	Every C<aio_*> function creates a request. which is a C data structure not	135	Every C<aio_*> function creates a request. which is a C data structure not
136	directly visible to Perl.	136	directly visible to Perl.
…		…
184		184
185	=cut	185	=cut
186		186
187	package IO::AIO;	187	package IO::AIO;
188		188
189	no warnings;	189	use Carp ();
190	use strict 'vars';	190
		191	use common::sense;
191		192
192	use base 'Exporter';	193	use base 'Exporter';
193		194
194	BEGIN {	195	BEGIN {
195	our $VERSION = '2.32';	196	our $VERSION = '3.4';
196		197
197	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	198	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	199	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	200	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
200	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree);	201	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		202	aio_rename aio_link aio_move aio_copy aio_group
		203	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		204	aio_chmod aio_utime aio_truncate
		205	aio_msync aio_mtouch);
		206
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	207	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	208	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	209	min_parallel max_parallel max_idle
204	nreqs nready npending nthreads	210	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	211	max_poll_time max_poll_reqs
		212	sendfile fadvise);
		213
		214	push @AIO_REQ, qw(aio_busy); # not exported
206		215
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		217
209	require XSLoader;	218	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	219	XSLoader::load ("IO::AIO", $VERSION);
…		…
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	226	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	227	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	228	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	229	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	230	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	231	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	232	syscall has been executed asynchronously.
224		233
225	All functions expecting a filehandle keep a copy of the filehandle	234	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	235	internally until the request has finished.
227		236
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	250	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)	251	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	252	use something else to ensure your scalar has the correct contents.
244		253
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	254	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	255	handles correctly whether it is set or not.
247		256
248	=over 4	257	=over 4
249		258
250	=item $prev_pri = aioreq_pri [$pri]	259	=item $prev_pri = aioreq_pri [$pri]
251		260
…		…
271	aio_read $_[0], ..., sub {	280	aio_read $_[0], ..., sub {
272	...	281	...
273	};	282	};
274	};	283	};
275		284
		285
276	=item aioreq_nice $pri_adjust	286	=item aioreq_nice $pri_adjust
277		287
278	Similar to C<aioreq_pri>, but subtracts the given value from the current	288	Similar to C<aioreq_pri>, but subtracts the given value from the current
279	priority, so the effect is cumulative.	289	priority, so the effect is cumulative.
		290
280		291
281	=item aio_open $pathname, $flags, $mode, $callback->($fh)	292	=item aio_open $pathname, $flags, $mode, $callback->($fh)
282		293
283	Asynchronously open or create a file and call the callback with a newly	294	Asynchronously open or create a file and call the callback with a newly
284	created filehandle for the file.	295	created filehandle for the file.
…		…
290	list. They are the same as used by C<sysopen>.	301	list. They are the same as used by C<sysopen>.
291		302
292	Likewise, C<$mode> specifies the mode of the newly created file, if it	303	Likewise, C<$mode> specifies the mode of the newly created file, if it
293	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	304	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
294	except that it is mandatory (i.e. use C<0> if you don't create new files,	305	except that it is mandatory (i.e. use C<0> if you don't create new files,
295	and C<0666> or C<0777> if you do).	306	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		307	by the umask in effect then the request is being executed, so better never
		308	change the umask.
296		309
297	Example:	310	Example:
298		311
299	aio_open "/etc/passwd", O_RDONLY, 0, sub {	312	aio_open "/etc/passwd", O_RDONLY, 0, sub {
300	if ($_[0]) {	313	if ($_[0]) {
…		…
303	} else {	316	} else {
304	die "open failed: $!\n";	317	die "open failed: $!\n";
305	}	318	}
306	};	319	};
307		320
		321
308	=item aio_close $fh, $callback->($status)	322	=item aio_close $fh, $callback->($status)
309		323
310	Asynchronously close a file and call the callback with the result	324	Asynchronously close a file and call the callback with the result
311	code. I<WARNING:> although accepted, you should not pass in a perl	325	code.
312	filehandle here, as perl will likely close the file descriptor another
313	time when the filehandle is destroyed. Normally, you can safely call perls
314	C<close> or just let filehandles go out of scope.
315		326
316	This is supposed to be a bug in the API, so that might change. It's	327	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
317	therefore best to avoid this function.	328	closing the file descriptor associated with the filehandle itself.
		329
		330	Therefore, C<aio_close> will not close the filehandle - instead it will
		331	use dup2 to overwrite the file descriptor with the write-end of a pipe
		332	(the pipe fd will be created on demand and will be cached).
		333
		334	Or in other words: the file descriptor will be closed, but it will not be
		335	free for reuse until the perl filehandle is closed.
		336
		337	=cut
318		338
319	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	339	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320		340
321	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	341	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322		342
323	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	343	Reads or writes C<$length> bytes from or to the specified C<$fh> and
324	into the scalar given by C<data> and offset C<dataoffset> and calls the	344	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
325	callback without the actual number of bytes read (or -1 on error, just	345	and calls the callback without the actual number of bytes read (or -1 on
326	like the syscall).	346	error, just like the syscall).
		347
		348	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		349	offset plus the actual number of bytes read.
		350
		351	If C<$offset> is undefined, then the current file descriptor offset will
		352	be used (and updated), otherwise the file descriptor offset will not be
		353	changed by these calls.
		354
		355	If C<$length> is undefined in C<aio_write>, use the remaining length of
		356	C<$data>.
		357
		358	If C<$dataoffset> is less than zero, it will be counted from the end of
		359	C<$data>.
327		360
328	The C<$data> scalar I<MUST NOT> be modified in any way while the request	361	The C<$data> scalar I<MUST NOT> be modified in any way while the request
329	is outstanding. Modifying it can result in segfaults or WW3 (if the	362	is outstanding. Modifying it can result in segfaults or World War III (if
330	necessary/optional hardware is installed).	363	the necessary/optional hardware is installed).
331		364
332	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	365	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
333	offset C<0> within the scalar:	366	offset C<0> within the scalar:
334		367
335	aio_read $fh, 7, 15, $buffer, 0, sub {	368	aio_read $fh, 7, 15, $buffer, 0, sub {
336	$_[0] > 0 or die "read error: $!";	369	$_[0] > 0 or die "read error: $!";
337	print "read $_[0] bytes: <$buffer>\n";	370	print "read $_[0] bytes: <$buffer>\n";
338	};	371	};
		372
339		373
340	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	374	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
341		375
342	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	376	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
343	reading at byte offset C<$in_offset>, and starts writing at the current	377	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
347		381
348	This call tries to make use of a native C<sendfile> syscall to provide	382	This call tries to make use of a native C<sendfile> syscall to provide
349	zero-copy operation. For this to work, C<$out_fh> should refer to a	383	zero-copy operation. For this to work, C<$out_fh> should refer to a
350	socket, and C<$in_fh> should refer to mmap'able file.	384	socket, and C<$in_fh> should refer to mmap'able file.
351		385
352	If the native sendfile call fails or is not implemented, it will be	386	If a native sendfile cannot be found or it fails with C<ENOSYS>,
		387	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
353	emulated, so you can call C<aio_sendfile> on any type of filehandle	388	it will be emulated, so you can call C<aio_sendfile> on any type of
354	regardless of the limitations of the operating system.	389	filehandle regardless of the limitations of the operating system.
355		390
356	Please note, however, that C<aio_sendfile> can read more bytes from	391	Please note, however, that C<aio_sendfile> can read more bytes from
357	C<$in_fh> than are written, and there is no way to find out how many	392	C<$in_fh> than are written, and there is no way to find out how many
358	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	393	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
359	provides the number of bytes written to C<$out_fh>. Only if the result	394	provides the number of bytes written to C<$out_fh>. Only if the result
360	value equals C<$length> one can assume that C<$length> bytes have been	395	value equals C<$length> one can assume that C<$length> bytes have been
361	read.	396	read.
		397
362		398
363	=item aio_readahead $fh,$offset,$length, $callback->($retval)	399	=item aio_readahead $fh,$offset,$length, $callback->($retval)
364		400
365	C<aio_readahead> populates the page cache with data from a file so that	401	C<aio_readahead> populates the page cache with data from a file so that
366	subsequent reads from that file will not block on disk I/O. The C<$offset>	402	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
372	file. The current file offset of the file is left unchanged.	408	file. The current file offset of the file is left unchanged.
373		409
374	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	410	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
375	emulated by simply reading the data, which would have a similar effect.	411	emulated by simply reading the data, which would have a similar effect.
376		412
		413
377	=item aio_stat $fh_or_path, $callback->($status)	414	=item aio_stat $fh_or_path, $callback->($status)
378		415
379	=item aio_lstat $fh, $callback->($status)	416	=item aio_lstat $fh, $callback->($status)
380		417
381	Works like perl's C<stat> or C<lstat> in void context. The callback will	418	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
394	aio_stat "/etc/passwd", sub {	431	aio_stat "/etc/passwd", sub {
395	$_[0] and die "stat failed: $!";	432	$_[0] and die "stat failed: $!";
396	print "size is ", -s _, "\n";	433	print "size is ", -s _, "\n";
397	};	434	};
398		435
		436
		437	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		438
		439	Works like perl's C<utime> function (including the special case of $atime
		440	and $mtime being undef). Fractional times are supported if the underlying
		441	syscalls support them.
		442
		443	When called with a pathname, uses utimes(2) if available, otherwise
		444	utime(2). If called on a file descriptor, uses futimes(2) if available,
		445	otherwise returns ENOSYS, so this is not portable.
		446
		447	Examples:
		448
		449	# set atime and mtime to current time (basically touch(1)):
		450	aio_utime "path", undef, undef;
		451	# set atime to current time and mtime to beginning of the epoch:
		452	aio_utime "path", time, undef; # undef==0
		453
		454
		455	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		456
		457	Works like perl's C<chown> function, except that C<undef> for either $uid
		458	or $gid is being interpreted as "do not change" (but -1 can also be used).
		459
		460	Examples:
		461
		462	# same as "chown root path" in the shell:
		463	aio_chown "path", 0, -1;
		464	# same as above:
		465	aio_chown "path", 0, undef;
		466
		467
		468	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		469
		470	Works like truncate(2) or ftruncate(2).
		471
		472
		473	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		474
		475	Works like perl's C<chmod> function.
		476
		477
399	=item aio_unlink $pathname, $callback->($status)	478	=item aio_unlink $pathname, $callback->($status)
400		479
401	Asynchronously unlink (delete) a file and call the callback with the	480	Asynchronously unlink (delete) a file and call the callback with the
402	result code.	481	result code.
403		482
		483
404	=item aio_mknod $path, $mode, $dev, $callback->($status)	484	=item aio_mknod $path, $mode, $dev, $callback->($status)
405		485
406	[EXPERIMENTAL]	486	[EXPERIMENTAL]
407		487
408	Asynchronously create a device node (or fifo). See mknod(2).	488	Asynchronously create a device node (or fifo). See mknod(2).
409		489
410	The only (POSIX-) portable way of calling this function is:	490	The only (POSIX-) portable way of calling this function is:
411		491
412	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	492	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		493
413		494
414	=item aio_link $srcpath, $dstpath, $callback->($status)	495	=item aio_link $srcpath, $dstpath, $callback->($status)
415		496
416	Asynchronously create a new link to the existing object at C<$srcpath> at	497	Asynchronously create a new link to the existing object at C<$srcpath> at
417	the path C<$dstpath> and call the callback with the result code.	498	the path C<$dstpath> and call the callback with the result code.
418		499
		500
419	=item aio_symlink $srcpath, $dstpath, $callback->($status)	501	=item aio_symlink $srcpath, $dstpath, $callback->($status)
420		502
421	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	503	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
422	the path C<$dstpath> and call the callback with the result code.	504	the path C<$dstpath> and call the callback with the result code.
		505
423		506
424	=item aio_readlink $path, $callback->($link)	507	=item aio_readlink $path, $callback->($link)
425		508
426	Asynchronously read the symlink specified by C<$path> and pass it to	509	Asynchronously read the symlink specified by C<$path> and pass it to
427	the callback. If an error occurs, nothing or undef gets passed to the	510	the callback. If an error occurs, nothing or undef gets passed to the
428	callback.	511	callback.
429		512
		513
430	=item aio_rename $srcpath, $dstpath, $callback->($status)	514	=item aio_rename $srcpath, $dstpath, $callback->($status)
431		515
432	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	516	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
433	rename(2) and call the callback with the result code.	517	rename(2) and call the callback with the result code.
434		518
		519
		520	=item aio_mkdir $pathname, $mode, $callback->($status)
		521
		522	Asynchronously mkdir (create) a directory and call the callback with
		523	the result code. C<$mode> will be modified by the umask at the time the
		524	request is executed, so do not change your umask.
		525
		526
435	=item aio_rmdir $pathname, $callback->($status)	527	=item aio_rmdir $pathname, $callback->($status)
436		528
437	Asynchronously rmdir (delete) a directory and call the callback with the	529	Asynchronously rmdir (delete) a directory and call the callback with the
438	result code.	530	result code.
		531
439		532
440	=item aio_readdir $pathname, $callback->($entries)	533	=item aio_readdir $pathname, $callback->($entries)
441		534
442	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	535	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
443	directory (i.e. opendir + readdir + closedir). The entries will not be	536	directory (i.e. opendir + readdir + closedir). The entries will not be
444	sorted, and will B<NOT> include the C<.> and C<..> entries.	537	sorted, and will B<NOT> include the C<.> and C<..> entries.
445		538
446	The callback a single argument which is either C<undef> or an array-ref	539	The callback is passed a single argument which is either C<undef> or an
447	with the filenames.	540	array-ref with the filenames.
		541
		542
		543	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		544
		545	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		546	behaviour and output format. In case of an error, C<$entries> will be
		547	C<undef>.
		548
		549	The flags are a combination of the following constants, ORed together (the
		550	flags will also be passed to the callback, possibly modified):
		551
		552	=over 4
		553
		554	=item IO::AIO::READDIR_DENTS
		555
		556	When this flag is off, then the callback gets an arrayref with of names
		557	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		558	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		559	entry in more detail.
		560
		561	C<$name> is the name of the entry.
		562
		563	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		564
		565	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		566	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		567	C<IO::AIO::DT_WHT>.
		568
		569	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		570	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		571	scalars are read-only: you can not modify them.
		572
		573	C<$inode> is the inode number (which might not be exact on systems with 64
		574	bit inode numbers and 32 bit perls). This field has unspecified content on
		575	systems that do not deliver the inode information.
		576
		577	=item IO::AIO::READDIR_DIRS_FIRST
		578
		579	When this flag is set, then the names will be returned in an order where
		580	likely directories come first. This is useful when you need to quickly
		581	find directories, or you want to find all directories while avoiding to
		582	stat() each entry.
		583
		584	If the system returns type information in readdir, then this is used
		585	to find directories directly. Otherwise, likely directories are files
		586	beginning with ".", or otherwise files with no dots, of which files with
		587	short names are tried first.
		588
		589	=item IO::AIO::READDIR_STAT_ORDER
		590
		591	When this flag is set, then the names will be returned in an order
		592	suitable for stat()'ing each one. That is, when you plan to stat()
		593	all files in the given directory, then the returned order will likely
		594	be fastest.
		595
		596	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		597	the likely dirs come first, resulting in a less optimal stat order.
		598
		599	=item IO::AIO::READDIR_FOUND_UNKNOWN
		600
		601	This flag should not be set when calling C<aio_readdirx>. Instead, it
		602	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		603	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		604	C<$type>'s are known, which can be used to speed up some algorithms.
		605
		606	=back
		607
448		608
449	=item aio_load $path, $data, $callback->($status)	609	=item aio_load $path, $data, $callback->($status)
450		610
451	This is a composite request that tries to fully load the given file into	611	This is a composite request that tries to fully load the given file into
452	memory. Status is the same as with aio_read.	612	memory. Status is the same as with aio_read.
453		613
454	=cut	614	=cut
455		615
456	sub aio_load($$;$) {	616	sub aio_load($$;$) {
457	aio_block {
458	my ($path, undef, $cb) = @_;	617	my ($path, undef, $cb) = @_;
459	my $data = \$_[1];	618	my $data = \$_[1];
460		619
461	my $pri = aioreq_pri;	620	my $pri = aioreq_pri;
462	my $grp = aio_group $cb;	621	my $grp = aio_group $cb;
		622
		623	aioreq_pri $pri;
		624	add $grp aio_open $path, O_RDONLY, 0, sub {
		625	my $fh = shift
		626	or return $grp->result (-1);
463		627
464	aioreq_pri $pri;	628	aioreq_pri $pri;
465	add $grp aio_open $path, O_RDONLY, 0, sub {
466	my ($fh) = @_
467	or return $grp->result (-1);
468
469	aioreq_pri $pri;
470	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {	629	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
471	$grp->result ($_[0]);	630	$grp->result ($_[0]);
472	};
473	};	631	};
474
475	$grp
476	}	632	};
		633
		634	$grp
477	}	635	}
478		636
479	=item aio_copy $srcpath, $dstpath, $callback->($status)	637	=item aio_copy $srcpath, $dstpath, $callback->($status)
480		638
481	Try to copy the I<file> (directories not supported as either source or	639	Try to copy the I<file> (directories not supported as either source or
482	destination) from C<$srcpath> to C<$dstpath> and call the callback with	640	destination) from C<$srcpath> to C<$dstpath> and call the callback with
483	the C<0> (error) or C<-1> ok.	641	a status of C<0> (ok) or C<-1> (error, see C<$!>).
484		642
485	This is a composite request that it creates the destination file with	643	This is a composite request that creates the destination file with
486	mode 0200 and copies the contents of the source file into it using	644	mode 0200 and copies the contents of the source file into it using
487	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	645	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
488	uid/gid, in that order.	646	uid/gid, in that order.
489		647
490	If an error occurs, the partial destination file will be unlinked, if	648	If an error occurs, the partial destination file will be unlinked, if
…		…
492	errors are being ignored.	650	errors are being ignored.
493		651
494	=cut	652	=cut
495		653
496	sub aio_copy($$;$) {	654	sub aio_copy($$;$) {
497	aio_block {
498	my ($src, $dst, $cb) = @_;	655	my ($src, $dst, $cb) = @_;
499		656
500	my $pri = aioreq_pri;	657	my $pri = aioreq_pri;
501	my $grp = aio_group $cb;	658	my $grp = aio_group $cb;
502		659
503	aioreq_pri $pri;	660	aioreq_pri $pri;
504	add $grp aio_open $src, O_RDONLY, 0, sub {	661	add $grp aio_open $src, O_RDONLY, 0, sub {
505	if (my $src_fh = $_[0]) {	662	if (my $src_fh = $_[0]) {
506	my @stat = stat $src_fh;	663	my @stat = stat $src_fh; # hmm, might block over nfs?
507		664
508	aioreq_pri $pri;	665	aioreq_pri $pri;
509	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	666	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
510	if (my $dst_fh = $_[0]) {	667	if (my $dst_fh = $_[0]) {
511	aioreq_pri $pri;	668	aioreq_pri $pri;
512	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	669	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
513	if ($_[0] == $stat[7]) {	670	if ($_[0] == $stat[7]) {
514	$grp->result (0);	671	$grp->result (0);
515	close $src_fh;	672	close $src_fh;
516		673
517	# those should not normally block. should. should.
518	utime $stat[8], $stat[9], $dst;
519	chmod $stat[2] & 07777, $dst_fh;
520	chown $stat[4], $stat[5], $dst_fh;
521	close $dst_fh;
522	} else {	674	my $ch = sub {
523	$grp->result (-1);
524	close $src_fh;
525	close $dst_fh;
526
527	aioreq $pri;	675	aioreq_pri $pri;
		676	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		677	aioreq_pri $pri;
		678	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		679	aioreq_pri $pri;
528	add $grp aio_unlink $dst;	680	add $grp aio_close $dst_fh;
		681	}
		682	};
529	}	683	};
		684
		685	aioreq_pri $pri;
		686	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		687	if ($_[0] < 0 && $! == ENOSYS) {
		688	aioreq_pri $pri;
		689	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		690	} else {
		691	$ch->();
		692	}
		693	};
		694	} else {
		695	$grp->result (-1);
		696	close $src_fh;
		697	close $dst_fh;
		698
		699	aioreq $pri;
		700	add $grp aio_unlink $dst;
530	};	701	}
531	} else {
532	$grp->result (-1);
533	}	702	};
		703	} else {
		704	$grp->result (-1);
534	},	705	}
535
536	} else {
537	$grp->result (-1);
538	}	706	},
		707
		708	} else {
		709	$grp->result (-1);
539	};	710	}
540
541	$grp
542	}	711	};
		712
		713	$grp
543	}	714	}
544		715
545	=item aio_move $srcpath, $dstpath, $callback->($status)	716	=item aio_move $srcpath, $dstpath, $callback->($status)
546		717
547	Try to move the I<file> (directories not supported as either source or	718	Try to move the I<file> (directories not supported as either source or
548	destination) from C<$srcpath> to C<$dstpath> and call the callback with	719	destination) from C<$srcpath> to C<$dstpath> and call the callback with
549	the C<0> (error) or C<-1> ok.	720	a status of C<0> (ok) or C<-1> (error, see C<$!>).
550		721
551	This is a composite request that tries to rename(2) the file first. If	722	This is a composite request that tries to rename(2) the file first; if
552	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	723	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
553	that is successful, unlinking the C<$srcpath>.	724	that is successful, unlinks the C<$srcpath>.
554		725
555	=cut	726	=cut
556		727
557	sub aio_move($$;$) {	728	sub aio_move($$;$) {
558	aio_block {
559	my ($src, $dst, $cb) = @_;	729	my ($src, $dst, $cb) = @_;
560		730
561	my $pri = aioreq_pri;	731	my $pri = aioreq_pri;
562	my $grp = aio_group $cb;	732	my $grp = aio_group $cb;
563		733
564	aioreq_pri $pri;	734	aioreq_pri $pri;
565	add $grp aio_rename $src, $dst, sub {	735	add $grp aio_rename $src, $dst, sub {
566	if ($_[0] && $! == EXDEV) {	736	if ($_[0] && $! == EXDEV) {
567	aioreq_pri $pri;	737	aioreq_pri $pri;
568	add $grp aio_copy $src, $dst, sub {	738	add $grp aio_copy $src, $dst, sub {
569	$grp->result ($_[0]);
570
571	if (!$_[0]) {
572	aioreq_pri $pri;
573	add $grp aio_unlink $src;
574	}
575	};
576	} else {
577	$grp->result ($_[0]);	739	$grp->result ($_[0]);
		740
		741	if (!$_[0]) {
		742	aioreq_pri $pri;
		743	add $grp aio_unlink $src;
		744	}
578	}	745	};
		746	} else {
		747	$grp->result ($_[0]);
579	};	748	}
580
581	$grp
582	}	749	};
		750
		751	$grp
583	}	752	}
584		753
585	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	754	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
586		755
587	Scans a directory (similar to C<aio_readdir>) but additionally tries to	756	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
607		776
608	Implementation notes.	777	Implementation notes.
609		778
610	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	779	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
611		780
		781	If readdir returns file type information, then this is used directly to
		782	find directories.
		783
612	After reading the directory, the modification time, size etc. of the	784	Otherwise, after reading the directory, the modification time, size etc.
613	directory before and after the readdir is checked, and if they match (and	785	of the directory before and after the readdir is checked, and if they
614	isn't the current time), the link count will be used to decide how many	786	match (and isn't the current time), the link count will be used to decide
615	entries are directories (if >= 2). Otherwise, no knowledge of the number	787	how many entries are directories (if >= 2). Otherwise, no knowledge of the
616	of subdirectories will be assumed.	788	number of subdirectories will be assumed.
617		789
618	Then entries will be sorted into likely directories (everything without	790	Then entries will be sorted into likely directories a non-initial dot
619	a non-initial dot currently) and likely non-directories (everything	791	currently) and likely non-directories (see C<aio_readdirx>). Then every
620	else). Then every entry plus an appended C</.> will be C<stat>'ed,	792	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
621	likely directories first. If that succeeds, it assumes that the entry	793	in order of their inode numbers. If that succeeds, it assumes that the
622	is a directory or a symlink to directory (which will be checked	794	entry is a directory or a symlink to directory (which will be checked
623	seperately). This is often faster than stat'ing the entry itself because	795	seperately). This is often faster than stat'ing the entry itself because
624	filesystems might detect the type of the entry without reading the inode	796	filesystems might detect the type of the entry without reading the inode
625	data (e.g. ext2fs filetype feature).	797	data (e.g. ext2fs filetype feature), even on systems that cannot return
		798	the filetype information on readdir.
626		799
627	If the known number of directories (link count - 2) has been reached, the	800	If the known number of directories (link count - 2) has been reached, the
628	rest of the entries is assumed to be non-directories.	801	rest of the entries is assumed to be non-directories.
629		802
630	This only works with certainty on POSIX (= UNIX) filesystems, which	803	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
635	directory counting heuristic.	808	directory counting heuristic.
636		809
637	=cut	810	=cut
638		811
639	sub aio_scandir($$;$) {	812	sub aio_scandir($$;$) {
640	aio_block {
641	my ($path, $maxreq, $cb) = @_;	813	my ($path, $maxreq, $cb) = @_;
642		814
643	my $pri = aioreq_pri;	815	my $pri = aioreq_pri;
644		816
645	my $grp = aio_group $cb;	817	my $grp = aio_group $cb;
646		818
647	$maxreq = 4 if $maxreq <= 0;	819	$maxreq = 4 if $maxreq <= 0;
648		820
649	# stat once	821	# stat once
		822	aioreq_pri $pri;
		823	add $grp aio_stat $path, sub {
		824	return $grp->result () if $_[0];
		825	my $now = time;
		826	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		827
		828	# read the directory entries
650	aioreq_pri $pri;	829	aioreq_pri $pri;
651	add $grp aio_stat $path, sub {	830	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		831	my $entries = shift
652	return $grp->result () if $_[0];	832	or return $grp->result ();
653	my $now = time;
654	my $hash1 = join ":", (stat _)[0,1,3,7,9];
655		833
656	# read the directory entries	834	# stat the dir another time
657	aioreq_pri $pri;	835	aioreq_pri $pri;
658	add $grp aio_readdir $path, sub {
659	my $entries = shift
660	or return $grp->result ();
661
662	# stat the dir another time
663	aioreq_pri $pri;
664	add $grp aio_stat $path, sub {	836	add $grp aio_stat $path, sub {
665	my $hash2 = join ":", (stat _)[0,1,3,7,9];	837	my $hash2 = join ":", (stat _)[0,1,3,7,9];
666		838
667	my $ndirs;	839	my $ndirs;
668		840
669	# take the slow route if anything looks fishy	841	# take the slow route if anything looks fishy
670	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	842	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
671	$ndirs = -1;	843	$ndirs = -1;
672	} else {	844	} else {
673	# if nlink == 2, we are finished	845	# if nlink == 2, we are finished
674	# on non-posix-fs's, we rely on nlink < 2	846	# for non-posix-fs's, we rely on nlink < 2
675	$ndirs = (stat _)[3] - 2	847	$ndirs = (stat _)[3] - 2
676	or return $grp->result ([], $entries);	848	or return $grp->result ([], $entries);
677	}	849	}
678		850
679	# sort into likely dirs and likely nondirs
680	# dirs == files without ".", short entries first
681	$entries = [map $_->[0],
682	sort { $b->[1] cmp $a->[1] }
683	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
684	@$entries];
685
686	my (@dirs, @nondirs);	851	my (@dirs, @nondirs);
687		852
688	my $statgrp = add $grp aio_group sub {	853	my $statgrp = add $grp aio_group sub {
689	$grp->result (\@dirs, \@nondirs);	854	$grp->result (\@dirs, \@nondirs);
690	};	855	};
691		856
692	limit $statgrp $maxreq;	857	limit $statgrp $maxreq;
693	feed $statgrp sub {	858	feed $statgrp sub {
694	return unless @$entries;	859	return unless @$entries;
695	my $entry = pop @$entries;	860	my $entry = shift @$entries;
696		861
697	aioreq_pri $pri;	862	aioreq_pri $pri;
698	add $statgrp aio_stat "$path/$entry/.", sub {	863	add $statgrp aio_stat "$path/$entry/.", sub {
699	if ($_[0] < 0) {	864	if ($_[0] < 0) {
700	push @nondirs, $entry;	865	push @nondirs, $entry;
701	} else {	866	} else {
702	# need to check for real directory	867	# need to check for real directory
703	aioreq_pri $pri;	868	aioreq_pri $pri;
704	add $statgrp aio_lstat "$path/$entry", sub {	869	add $statgrp aio_lstat "$path/$entry", sub {
705	if (-d _) {	870	if (-d _) {
706	push @dirs, $entry;	871	push @dirs, $entry;
707		872
708	unless (--$ndirs) {	873	unless (--$ndirs) {
709	push @nondirs, @$entries;	874	push @nondirs, @$entries;
710	feed $statgrp;	875	feed $statgrp;
711	}
712	} else {
713	push @nondirs, $entry;
714	}	876	}
		877	} else {
		878	push @nondirs, $entry;
715	}	879	}
716	}	880	}
717	};	881	}
718	};	882	};
719	};	883	};
720	};	884	};
721	};	885	};
722
723	$grp
724	}	886	};
		887
		888	$grp
725	}	889	}
726		890
727	=item aio_rmtree $path, $callback->($status)	891	=item aio_rmtree $path, $callback->($status)
728		892
729	Delete a directory tree starting (and including) C<$path>, return the	893	Delete a directory tree starting (and including) C<$path>, return the
…		…
733		897
734	=cut	898	=cut
735		899
736	sub aio_rmtree;	900	sub aio_rmtree;
737	sub aio_rmtree($;$) {	901	sub aio_rmtree($;$) {
738	aio_block {
739	my ($path, $cb) = @_;	902	my ($path, $cb) = @_;
740		903
741	my $pri = aioreq_pri;	904	my $pri = aioreq_pri;
742	my $grp = aio_group $cb;	905	my $grp = aio_group $cb;
743		906
744	aioreq_pri $pri;	907	aioreq_pri $pri;
745	add $grp aio_scandir $path, 0, sub {	908	add $grp aio_scandir $path, 0, sub {
746	my ($dirs, $nondirs) = @_;	909	my ($dirs, $nondirs) = @_;
747		910
748	my $dirgrp = aio_group sub {	911	my $dirgrp = aio_group sub {
749	add $grp aio_rmdir $path, sub {	912	add $grp aio_rmdir $path, sub {
750	$grp->result ($_[0]);	913	$grp->result ($_[0]);
751	};
752	};	914	};
753
754	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
755	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
756
757	add $grp $dirgrp;
758	};	915	};
759		916
760	$grp	917	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		918	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		919
		920	add $grp $dirgrp;
761	}	921	};
		922
		923	$grp
762	}	924	}
		925
		926	=item aio_sync $callback->($status)
		927
		928	Asynchronously call sync and call the callback when finished.
763		929
764	=item aio_fsync $fh, $callback->($status)	930	=item aio_fsync $fh, $callback->($status)
765		931
766	Asynchronously call fsync on the given filehandle and call the callback	932	Asynchronously call fsync on the given filehandle and call the callback
767	with the fsync result code.	933	with the fsync result code.
…		…
771	Asynchronously call fdatasync on the given filehandle and call the	937	Asynchronously call fdatasync on the given filehandle and call the
772	callback with the fdatasync result code.	938	callback with the fdatasync result code.
773		939
774	If this call isn't available because your OS lacks it or it couldn't be	940	If this call isn't available because your OS lacks it or it couldn't be
775	detected, it will be emulated by calling C<fsync> instead.	941	detected, it will be emulated by calling C<fsync> instead.
		942
		943	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		944
		945	Sync the data portion of the file specified by C<$offset> and C<$length>
		946	to disk (but NOT the metadata), by calling the Linux-specific
		947	sync_file_range call. If sync_file_range is not available or it returns
		948	ENOSYS, then fdatasync or fsync is being substituted.
		949
		950	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		951	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		952	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		953	manpage for details.
		954
		955	=item aio_pathsync $path, $callback->($status)
		956
		957	This request tries to open, fsync and close the given path. This is a
		958	composite request intended to sync directories after directory operations
		959	(E.g. rename). This might not work on all operating systems or have any
		960	specific effect, but usually it makes sure that directory changes get
		961	written to disc. It works for anything that can be opened for read-only,
		962	not just directories.
		963
		964	Future versions of this function might fall back to other methods when
		965	C<fsync> on the directory fails (such as calling C<sync>).
		966
		967	Passes C<0> when everything went ok, and C<-1> on error.
		968
		969	=cut
		970
		971	sub aio_pathsync($;$) {
		972	my ($path, $cb) = @_;
		973
		974	my $pri = aioreq_pri;
		975	my $grp = aio_group $cb;
		976
		977	aioreq_pri $pri;
		978	add $grp aio_open $path, O_RDONLY, 0, sub {
		979	my ($fh) = @_;
		980	if ($fh) {
		981	aioreq_pri $pri;
		982	add $grp aio_fsync $fh, sub {
		983	$grp->result ($_[0]);
		984
		985	aioreq_pri $pri;
		986	add $grp aio_close $fh;
		987	};
		988	} else {
		989	$grp->result (-1);
		990	}
		991	};
		992
		993	$grp
		994	}
		995
		996	=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		997
		998	This is a rather advanced IO::AIO call, which only works on mmap(2)ed
		999	scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note
		1000	that the scalar must only be modified in-place while an aio operation is
		1001	pending on it).
		1002
		1003	It calls the C<msync> function of your OS, if available, with the memory
		1004	area starting at C<$offset> in the string and ending C<$length> bytes
		1005	later. If C<$length> is negative, counts from the end, and if C<$length>
		1006	is C<undef>, then it goes till the end of the string. The flags can be
		1007	a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
		1008	C<IO::AIO::MS_SYNC>.
		1009
		1010	=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
		1011
		1012	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
		1013	scalars.
		1014
		1015	It touches (reads or writes) all memory pages in the specified
		1016	range inside the scalar. All caveats and parameters are the same
		1017	as for C<aio_msync>, above, except for flags, which must be either
		1018	C<0> (which reads all pages and ensures they are instantiated) or
		1019	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
		1020	writing an octet from it, which dirties the page).
776		1021
777	=item aio_group $callback->(...)	1022	=item aio_group $callback->(...)
778		1023
779	This is a very special aio request: Instead of doing something, it is a	1024	This is a very special aio request: Instead of doing something, it is a
780	container for other aio requests, which is useful if you want to bundle	1025	container for other aio requests, which is useful if you want to bundle
…		…
830	=item cancel $req	1075	=item cancel $req
831		1076
832	Cancels the request, if possible. Has the effect of skipping execution	1077	Cancels the request, if possible. Has the effect of skipping execution
833	when entering the B<execute> state and skipping calling the callback when	1078	when entering the B<execute> state and skipping calling the callback when
834	entering the the B<result> state, but will leave the request otherwise	1079	entering the the B<result> state, but will leave the request otherwise
835	untouched. That means that requests that currently execute will not be	1080	untouched (with the exception of readdir). That means that requests that
836	stopped and resources held by the request will not be freed prematurely.	1081	currently execute will not be stopped and resources held by the request
		1082	will not be freed prematurely.
837		1083
838	=item cb $req $callback->(...)	1084	=item cb $req $callback->(...)
839		1085
840	Replace (or simply set) the callback registered to the request.	1086	Replace (or simply set) the callback registered to the request.
841		1087
…		…
892	Their lifetime, simplified, looks like this: when they are empty, they	1138	Their lifetime, simplified, looks like this: when they are empty, they
893	will finish very quickly. If they contain only requests that are in the	1139	will finish very quickly. If they contain only requests that are in the
894	C<done> state, they will also finish. Otherwise they will continue to	1140	C<done> state, they will also finish. Otherwise they will continue to
895	exist.	1141	exist.
896		1142
897	That means after creating a group you have some time to add requests. And	1143	That means after creating a group you have some time to add requests
898	in the callbacks of those requests, you can add further requests to the	1144	(precisely before the callback has been invoked, which is only done within
899	group. And only when all those requests have finished will the the group	1145	the C<poll_cb>). And in the callbacks of those requests, you can add
900	itself finish.	1146	further requests to the group. And only when all those requests have
		1147	finished will the the group itself finish.
901		1148
902	=over 4	1149	=over 4
903		1150
904	=item add $grp ...	1151	=item add $grp ...
905		1152
…		…
914	=item $grp->cancel_subs	1161	=item $grp->cancel_subs
915		1162
916	Cancel all subrequests and clears any feeder, but not the group request	1163	Cancel all subrequests and clears any feeder, but not the group request
917	itself. Useful when you queued a lot of events but got a result early.	1164	itself. Useful when you queued a lot of events but got a result early.
918		1165
		1166	The group request will finish normally (you cannot add requests to the
		1167	group).
		1168
919	=item $grp->result (...)	1169	=item $grp->result (...)
920		1170
921	Set the result value(s) that will be passed to the group callback when all	1171	Set the result value(s) that will be passed to the group callback when all
922	subrequests have finished and set thre groups errno to the current value	1172	subrequests have finished and set the groups errno to the current value
923	of errno (just like calling C<errno> without an error number). By default,	1173	of errno (just like calling C<errno> without an error number). By default,
924	no argument will be passed and errno is zero.	1174	no argument will be passed and errno is zero.
925		1175
926	=item $grp->errno ([$errno])	1176	=item $grp->errno ([$errno])
927		1177
…		…
938	=item feed $grp $callback->($grp)	1188	=item feed $grp $callback->($grp)
939		1189
940	Sets a feeder/generator on this group: every group can have an attached	1190	Sets a feeder/generator on this group: every group can have an attached
941	generator that generates requests if idle. The idea behind this is that,	1191	generator that generates requests if idle. The idea behind this is that,
942	although you could just queue as many requests as you want in a group,	1192	although you could just queue as many requests as you want in a group,
943	this might starve other requests for a potentially long time. For	1193	this might starve other requests for a potentially long time. For example,
944	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1194	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
945	requests, delaying any later requests for a long time.	1195	delaying any later requests for a long time.
946		1196
947	To avoid this, and allow incremental generation of requests, you can	1197	To avoid this, and allow incremental generation of requests, you can
948	instead a group and set a feeder on it that generates those requests. The	1198	instead a group and set a feeder on it that generates those requests. The
949	feed callback will be called whenever there are few enough (see C<limit>,	1199	feed callback will be called whenever there are few enough (see C<limit>,
950	below) requests active in the group itself and is expected to queue more	1200	below) requests active in the group itself and is expected to queue more
…		…
954	not impose any limits).	1204	not impose any limits).
955		1205
956	If the feed does not queue more requests when called, it will be	1206	If the feed does not queue more requests when called, it will be
957	automatically removed from the group.	1207	automatically removed from the group.
958		1208
959	If the feed limit is C<0>, it will be set to C<2> automatically.	1209	If the feed limit is C<0> when this method is called, it will be set to
		1210	C<2> automatically.
960		1211
961	Example:	1212	Example:
962		1213
963	# stat all files in @files, but only ever use four aio requests concurrently:	1214	# stat all files in @files, but only ever use four aio requests concurrently:
964		1215
…		…
976	Sets the feeder limit for the group: The feeder will be called whenever	1227	Sets the feeder limit for the group: The feeder will be called whenever
977	the group contains less than this many requests.	1228	the group contains less than this many requests.
978		1229
979	Setting the limit to C<0> will pause the feeding process.	1230	Setting the limit to C<0> will pause the feeding process.
980		1231
		1232	The default value for the limit is C<0>, but note that setting a feeder
		1233	automatically bumps it up to C<2>.
		1234
981	=back	1235	=back
982		1236
983	=head2 SUPPORT FUNCTIONS	1237	=head2 SUPPORT FUNCTIONS
984		1238
985	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1239	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
987	=over 4	1241	=over 4
988		1242
989	=item $fileno = IO::AIO::poll_fileno	1243	=item $fileno = IO::AIO::poll_fileno
990		1244
991	Return the I<request result pipe file descriptor>. This filehandle must be	1245	Return the I<request result pipe file descriptor>. This filehandle must be
992	polled for reading by some mechanism outside this module (e.g. Event or	1246	polled for reading by some mechanism outside this module (e.g. EV, Glib,
993	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1247	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
994	to call C<poll_cb> to check the results.	1248	you have to call C<poll_cb> to check the results.
995		1249
996	See C<poll_cb> for an example.	1250	See C<poll_cb> for an example.
997		1251
998	=item IO::AIO::poll_cb	1252	=item IO::AIO::poll_cb
999		1253
1000	Process some outstanding events on the result pipe. You have to call this	1254	Process some outstanding events on the result pipe. You have to call this
1001	regularly. Returns the number of events processed. Returns immediately	1255	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1256	returned earlier for whatever reason. Returns immediately when no events
1002	when no events are outstanding. The amount of events processed depends on	1257	are outstanding. The amount of events processed depends on the settings of
1003	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1258	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1004		1259
1005	If not all requests were processed for whatever reason, the filehandle	1260	If not all requests were processed for whatever reason, the filehandle
1006	will still be ready when C<poll_cb> returns.	1261	will still be ready when C<poll_cb> returns, so normally you don't have to
		1262	do anything special to have it called later.
1007		1263
1008	Example: Install an Event watcher that automatically calls	1264	Example: Install an Event watcher that automatically calls
1009	IO::AIO::poll_cb with high priority:	1265	IO::AIO::poll_cb with high priority (more examples can be found in the
		1266	SYNOPSIS section, at the top of this document):
1010		1267
1011	Event->io (fd => IO::AIO::poll_fileno,	1268	Event->io (fd => IO::AIO::poll_fileno,
1012	poll => 'r', async => 1,	1269	poll => 'r', async => 1,
1013	cb => \&IO::AIO::poll_cb);	1270	cb => \&IO::AIO::poll_cb);
1014		1271
…		…
1070	Strictly equivalent to:	1327	Strictly equivalent to:
1071		1328
1072	IO::AIO::poll_wait, IO::AIO::poll_cb	1329	IO::AIO::poll_wait, IO::AIO::poll_cb
1073	while IO::AIO::nreqs;	1330	while IO::AIO::nreqs;
1074		1331
		1332	=back
		1333
1075	=head3 CONTROLLING THE NUMBER OF THREADS	1334	=head3 CONTROLLING THE NUMBER OF THREADS
		1335
		1336	=over
1076		1337
1077	=item IO::AIO::min_parallel $nthreads	1338	=item IO::AIO::min_parallel $nthreads
1078		1339
1079	Set the minimum number of AIO threads to C<$nthreads>. The current	1340	Set the minimum number of AIO threads to C<$nthreads>. The current
1080	default is C<8>, which means eight asynchronous operations can execute	1341	default is C<8>, which means eight asynchronous operations can execute
…		…
1121		1382
1122	The default is probably ok in most situations, especially if thread	1383	The default is probably ok in most situations, especially if thread
1123	creation is fast. If thread creation is very slow on your system you might	1384	creation is fast. If thread creation is very slow on your system you might
1124	want to use larger values.	1385	want to use larger values.
1125		1386
1126	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1387	=item IO::AIO::max_outstanding $maxreqs
1127		1388
1128	This is a very bad function to use in interactive programs because it	1389	This is a very bad function to use in interactive programs because it
1129	blocks, and a bad way to reduce concurrency because it is inexact: Better	1390	blocks, and a bad way to reduce concurrency because it is inexact: Better
1130	use an C<aio_group> together with a feed callback.	1391	use an C<aio_group> together with a feed callback.
1131		1392
1132	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1393	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1133	to queue up more than this number of requests, the next call to the	1394	do queue up more than this number of requests, the next call to the
1134	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1395	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1135	function will block until the limit is no longer exceeded.	1396	function will block until the limit is no longer exceeded.
1136		1397
1137	The default value is very large, so there is no practical limit on the	1398	The default value is very large, so there is no practical limit on the
1138	number of outstanding requests.	1399	number of outstanding requests.
1139		1400
1140	You can still queue as many requests as you want. Therefore,	1401	You can still queue as many requests as you want. Therefore,
1141	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1402	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1142	as a stop gap to shield against fatal memory overflow (with large values).	1403	as a stop gap to shield against fatal memory overflow (with large values).
1143		1404
		1405	=back
		1406
1144	=head3 STATISTICAL INFORMATION	1407	=head3 STATISTICAL INFORMATION
		1408
		1409	=over
1145		1410
1146	=item IO::AIO::nreqs	1411	=item IO::AIO::nreqs
1147		1412
1148	Returns the number of requests currently in the ready, execute or pending	1413	Returns the number of requests currently in the ready, execute or pending
1149	states (i.e. for which their callback has not been invoked yet).	1414	states (i.e. for which their callback has not been invoked yet).
…		…
1163	Returns the number of requests currently in the pending state (executed,	1428	Returns the number of requests currently in the pending state (executed,
1164	but not yet processed by poll_cb).	1429	but not yet processed by poll_cb).
1165		1430
1166	=back	1431	=back
1167		1432
		1433	=head3 MISCELLANEOUS FUNCTIONS
		1434
		1435	IO::AIO implements some functions that might be useful, but are not
		1436	asynchronous.
		1437
		1438	=over 4
		1439
		1440	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1441
		1442	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1443	but is blocking (this makes most sense if you know the input data is
		1444	likely cached already and the output filehandle is set to non-blocking
		1445	operations).
		1446
		1447	Returns the number of bytes copied, or C<-1> on error.
		1448
		1449	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1450
		1451	Simply calls the C<posix_fadvise> function (see it's
		1452	manpage for details). The following advice constants are
		1453	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1454	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1455	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1456
		1457	On systems that do not implement C<posix_fadvise>, this function returns
		1458	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1459
		1460	=back
		1461
1168	=cut	1462	=cut
1169
1170	# support function to convert a fd into a perl filehandle
1171	sub _fd2fh {
1172	return undef if $_[0] < 0;
1173
1174	# try to generate nice filehandles
1175	my $sym = "IO::AIO::fd#$_[0]";
1176	local *$sym;
1177
1178	open *$sym, "+<&=$_[0]" # usually works under any unix
1179	or open *$sym, "<&=$_[0]" # cygwin needs this
1180	or open *$sym, ">&=$_[0]" # or this
1181	or return undef;
1182
1183	*$sym
1184	}
1185		1463
1186	min_parallel 8;	1464	min_parallel 8;
1187		1465
1188	END { flush }	1466	END { flush }
1189		1467
…		…
1213	bytes of memory. In addition, stat requests need a stat buffer (possibly	1491	bytes of memory. In addition, stat requests need a stat buffer (possibly
1214	a few hundred bytes), readdir requires a result buffer and so on. Perl	1492	a few hundred bytes), readdir requires a result buffer and so on. Perl
1215	scalars and other data passed into aio requests will also be locked and	1493	scalars and other data passed into aio requests will also be locked and
1216	will consume memory till the request has entered the done state.	1494	will consume memory till the request has entered the done state.
1217		1495
1218	This is now awfully much, so queuing lots of requests is not usually a	1496	This is not awfully much, so queuing lots of requests is not usually a
1219	problem.	1497	problem.
1220		1498
1221	Per-thread usage:	1499	Per-thread usage:
1222		1500
1223	In the execution phase, some aio requests require more memory for	1501	In the execution phase, some aio requests require more memory for
…		…
1228		1506
1229	Known bugs will be fixed in the next release.	1507	Known bugs will be fixed in the next release.
1230		1508
1231	=head1 SEE ALSO	1509	=head1 SEE ALSO
1232		1510
1233	L<Coro::AIO>.	1511	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1512	more natural syntax.
1234		1513
1235	=head1 AUTHOR	1514	=head1 AUTHOR
1236		1515
1237	Marc Lehmann <schmorp@schmorp.de>	1516	Marc Lehmann <schmorp@schmorp.de>
1238	http://home.schmorp.de/	1517	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.100 by root, Sun Jan 7 21:36:58 2007 UTC vs. Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.100 by root, Sun Jan 7 21:36:58 2007 UTC vs.
Revision 1.171 by root, Sat Jan 2 14:24:32 2010 UTC