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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.96 by root, Fri Dec 22 04:05:50 2006 UTC vs.
Revision 1.167 by root, Thu Nov 12 01:15:36 2009 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 = '2.21';	196	our $VERSION = '3.31';
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);	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
201	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));	206	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	207	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203	min_parallel max_parallel max_idle	208	min_parallel max_parallel max_idle
204	nreqs nready npending nthreads	209	nreqs nready npending nthreads
205	max_poll_time max_poll_reqs);	210	max_poll_time max_poll_reqs
		211	sendfile fadvise);
		212
		213	push @AIO_REQ, qw(aio_busy); # not exported
206		214
207	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	215	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208		216
209	require XSLoader;	217	require XSLoader;
210	XSLoader::load ("IO::AIO", $VERSION);	218	XSLoader::load ("IO::AIO", $VERSION);
…		…
217	All the C<aio_*> calls are more or less thin wrappers around the syscall	225	All the C<aio_*> calls are more or less thin wrappers around the syscall
218	with the same name (sans C<aio_>). The arguments are similar or identical,	226	with the same name (sans C<aio_>). The arguments are similar or identical,
219	and they all accept an additional (and optional) C<$callback> argument	227	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	228	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	229	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	230	perl, which usually delivers "false") as its sole argument after the given
223	syscall has been executed asynchronously.	231	syscall has been executed asynchronously.
224		232
225	All functions expecting a filehandle keep a copy of the filehandle	233	All functions expecting a filehandle keep a copy of the filehandle
226	internally until the request has finished.	234	internally until the request has finished.
227		235
…		…
241	your pathnames to the locale (or other) encoding in effect in the user	249	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)	250	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243	use something else to ensure your scalar has the correct contents.	251	use something else to ensure your scalar has the correct contents.
244		252
245	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	253	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246	handles correctly wether it is set or not.	254	handles correctly whether it is set or not.
247		255
248	=over 4	256	=over 4
249		257
250	=item $prev_pri = aioreq_pri [$pri]	258	=item $prev_pri = aioreq_pri [$pri]
251		259
…		…
271	aio_read $_[0], ..., sub {	279	aio_read $_[0], ..., sub {
272	...	280	...
273	};	281	};
274	};	282	};
275		283
		284
276	=item aioreq_nice $pri_adjust	285	=item aioreq_nice $pri_adjust
277		286
278	Similar to C<aioreq_pri>, but subtracts the given value from the current	287	Similar to C<aioreq_pri>, but subtracts the given value from the current
279	priority, so the effect is cumulative.	288	priority, so the effect is cumulative.
		289
280		290
281	=item aio_open $pathname, $flags, $mode, $callback->($fh)	291	=item aio_open $pathname, $flags, $mode, $callback->($fh)
282		292
283	Asynchronously open or create a file and call the callback with a newly	293	Asynchronously open or create a file and call the callback with a newly
284	created filehandle for the file.	294	created filehandle for the file.
…		…
290	list. They are the same as used by C<sysopen>.	300	list. They are the same as used by C<sysopen>.
291		301
292	Likewise, C<$mode> specifies the mode of the newly created file, if it	302	Likewise, C<$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>,	303	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,	304	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).	305	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		306	by the umask in effect then the request is being executed, so better never
		307	change the umask.
296		308
297	Example:	309	Example:
298		310
299	aio_open "/etc/passwd", O_RDONLY, 0, sub {	311	aio_open "/etc/passwd", O_RDONLY, 0, sub {
300	if ($_[0]) {	312	if ($_[0]) {
…		…
303	} else {	315	} else {
304	die "open failed: $!\n";	316	die "open failed: $!\n";
305	}	317	}
306	};	318	};
307		319
		320
308	=item aio_close $fh, $callback->($status)	321	=item aio_close $fh, $callback->($status)
309		322
310	Asynchronously close a file and call the callback with the result	323	Asynchronously close a file and call the callback with the result
311	code. I<WARNING:> although accepted, you should not pass in a perl	324	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		325
316	This is supposed to be a bug in the API, so that might change. It's	326	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
317	therefore best to avoid this function.	327	closing the file descriptor associated with the filehandle itself.
		328
		329	Therefore, C<aio_close> will not close the filehandle - instead it will
		330	use dup2 to overwrite the file descriptor with the write-end of a pipe
		331	(the pipe fd will be created on demand and will be cached).
		332
		333	Or in other words: the file descriptor will be closed, but it will not be
		334	free for reuse until the perl filehandle is closed.
		335
		336	=cut
318		337
319	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	338	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320		339
321	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	340	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322		341
323	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	342	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	343	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
325	callback without the actual number of bytes read (or -1 on error, just	344	and calls the callback without the actual number of bytes read (or -1 on
326	like the syscall).	345	error, just like the syscall).
		346
		347	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		348	offset plus the actual number of bytes read.
		349
		350	If C<$offset> is undefined, then the current file descriptor offset will
		351	be used (and updated), otherwise the file descriptor offset will not be
		352	changed by these calls.
		353
		354	If C<$length> is undefined in C<aio_write>, use the remaining length of
		355	C<$data>.
		356
		357	If C<$dataoffset> is less than zero, it will be counted from the end of
		358	C<$data>.
327		359
328	The C<$data> scalar I<MUST NOT> be modified in any way while the request	360	The C<$data> scalar I<MUST NOT> be modified in any way while the request
329	is outstanding. Modifying it can result in segfaults or WW3 (if the	361	is outstanding. Modifying it can result in segfaults or World War III (if
330	necessary/optional hardware is installed).	362	the necessary/optional hardware is installed).
331		363
332	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	364	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
333	offset C<0> within the scalar:	365	offset C<0> within the scalar:
334		366
335	aio_read $fh, 7, 15, $buffer, 0, sub {	367	aio_read $fh, 7, 15, $buffer, 0, sub {
336	$_[0] > 0 or die "read error: $!";	368	$_[0] > 0 or die "read error: $!";
337	print "read $_[0] bytes: <$buffer>\n";	369	print "read $_[0] bytes: <$buffer>\n";
338	};	370	};
		371
339		372
340	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	373	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
341		374
342	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	375	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
343	reading at byte offset C<$in_offset>, and starts writing at the current	376	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
357	C<$in_fh> than are written, and there is no way to find out how many	390	C<$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	391	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
359	provides the number of bytes written to C<$out_fh>. Only if the result	392	provides the number of bytes written to C<$out_fh>. Only if the result
360	value equals C<$length> one can assume that C<$length> bytes have been	393	value equals C<$length> one can assume that C<$length> bytes have been
361	read.	394	read.
		395
362		396
363	=item aio_readahead $fh,$offset,$length, $callback->($retval)	397	=item aio_readahead $fh,$offset,$length, $callback->($retval)
364		398
365	C<aio_readahead> populates the page cache with data from a file so that	399	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<$offset>	400	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
372	file. The current file offset of the file is left unchanged.	406	file. The current file offset of the file is left unchanged.
373		407
374	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	408	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.	409	emulated by simply reading the data, which would have a similar effect.
376		410
		411
377	=item aio_stat $fh_or_path, $callback->($status)	412	=item aio_stat $fh_or_path, $callback->($status)
378		413
379	=item aio_lstat $fh, $callback->($status)	414	=item aio_lstat $fh, $callback->($status)
380		415
381	Works like perl's C<stat> or C<lstat> in void context. The callback will	416	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
394	aio_stat "/etc/passwd", sub {	429	aio_stat "/etc/passwd", sub {
395	$_[0] and die "stat failed: $!";	430	$_[0] and die "stat failed: $!";
396	print "size is ", -s _, "\n";	431	print "size is ", -s _, "\n";
397	};	432	};
398		433
		434
		435	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		436
		437	Works like perl's C<utime> function (including the special case of $atime
		438	and $mtime being undef). Fractional times are supported if the underlying
		439	syscalls support them.
		440
		441	When called with a pathname, uses utimes(2) if available, otherwise
		442	utime(2). If called on a file descriptor, uses futimes(2) if available,
		443	otherwise returns ENOSYS, so this is not portable.
		444
		445	Examples:
		446
		447	# set atime and mtime to current time (basically touch(1)):
		448	aio_utime "path", undef, undef;
		449	# set atime to current time and mtime to beginning of the epoch:
		450	aio_utime "path", time, undef; # undef==0
		451
		452
		453	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		454
		455	Works like perl's C<chown> function, except that C<undef> for either $uid
		456	or $gid is being interpreted as "do not change" (but -1 can also be used).
		457
		458	Examples:
		459
		460	# same as "chown root path" in the shell:
		461	aio_chown "path", 0, -1;
		462	# same as above:
		463	aio_chown "path", 0, undef;
		464
		465
		466	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		467
		468	Works like truncate(2) or ftruncate(2).
		469
		470
		471	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		472
		473	Works like perl's C<chmod> function.
		474
		475
399	=item aio_unlink $pathname, $callback->($status)	476	=item aio_unlink $pathname, $callback->($status)
400		477
401	Asynchronously unlink (delete) a file and call the callback with the	478	Asynchronously unlink (delete) a file and call the callback with the
402	result code.	479	result code.
403		480
		481
404	=item aio_mknod $path, $mode, $dev, $callback->($status)	482	=item aio_mknod $path, $mode, $dev, $callback->($status)
405		483
406	[EXPERIMENTAL]	484	[EXPERIMENTAL]
407		485
408	Asynchronously create a device node (or fifo). See mknod(2).	486	Asynchronously create a device node (or fifo). See mknod(2).
409		487
410	The only (POSIX-) portable way of calling this function is:	488	The only (POSIX-) portable way of calling this function is:
411		489
412	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	490	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		491
413		492
414	=item aio_link $srcpath, $dstpath, $callback->($status)	493	=item aio_link $srcpath, $dstpath, $callback->($status)
415		494
416	Asynchronously create a new link to the existing object at C<$srcpath> at	495	Asynchronously create a new link to the existing object at C<$srcpath> at
417	the path C<$dstpath> and call the callback with the result code.	496	the path C<$dstpath> and call the callback with the result code.
418		497
		498
419	=item aio_symlink $srcpath, $dstpath, $callback->($status)	499	=item aio_symlink $srcpath, $dstpath, $callback->($status)
420		500
421	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	501	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
422	the path C<$dstpath> and call the callback with the result code.	502	the path C<$dstpath> and call the callback with the result code.
		503
423		504
424	=item aio_readlink $path, $callback->($link)	505	=item aio_readlink $path, $callback->($link)
425		506
426	Asynchronously read the symlink specified by C<$path> and pass it to	507	Asynchronously read the symlink specified by C<$path> and pass it to
427	the callback. If an error occurs, nothing or undef gets passed to the	508	the callback. If an error occurs, nothing or undef gets passed to the
428	callback.	509	callback.
429		510
		511
430	=item aio_rename $srcpath, $dstpath, $callback->($status)	512	=item aio_rename $srcpath, $dstpath, $callback->($status)
431		513
432	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	514	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
433	rename(2) and call the callback with the result code.	515	rename(2) and call the callback with the result code.
434		516
		517
		518	=item aio_mkdir $pathname, $mode, $callback->($status)
		519
		520	Asynchronously mkdir (create) a directory and call the callback with
		521	the result code. C<$mode> will be modified by the umask at the time the
		522	request is executed, so do not change your umask.
		523
		524
435	=item aio_rmdir $pathname, $callback->($status)	525	=item aio_rmdir $pathname, $callback->($status)
436		526
437	Asynchronously rmdir (delete) a directory and call the callback with the	527	Asynchronously rmdir (delete) a directory and call the callback with the
438	result code.	528	result code.
		529
439		530
440	=item aio_readdir $pathname, $callback->($entries)	531	=item aio_readdir $pathname, $callback->($entries)
441		532
442	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	533	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	534	directory (i.e. opendir + readdir + closedir). The entries will not be
444	sorted, and will B<NOT> include the C<.> and C<..> entries.	535	sorted, and will B<NOT> include the C<.> and C<..> entries.
445		536
446	The callback a single argument which is either C<undef> or an array-ref	537	The callback is passed a single argument which is either C<undef> or an
447	with the filenames.	538	array-ref with the filenames.
		539
		540
		541	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		542
		543	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		544	behaviour and output format. In case of an error, C<$entries> will be
		545	C<undef>.
		546
		547	The flags are a combination of the following constants, ORed together (the
		548	flags will also be passed to the callback, possibly modified):
		549
		550	=over 4
		551
		552	=item IO::AIO::READDIR_DENTS
		553
		554	When this flag is off, then the callback gets an arrayref with of names
		555	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		556	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		557	entry in more detail.
		558
		559	C<$name> is the name of the entry.
		560
		561	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		562
		563	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		564	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		565	C<IO::AIO::DT_WHT>.
		566
		567	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		568	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		569	scalars are read-only: you can not modify them.
		570
		571	C<$inode> is the inode number (which might not be exact on systems with 64
		572	bit inode numbers and 32 bit perls). This field has unspecified content on
		573	systems that do not deliver the inode information.
		574
		575	=item IO::AIO::READDIR_DIRS_FIRST
		576
		577	When this flag is set, then the names will be returned in an order where
		578	likely directories come first. This is useful when you need to quickly
		579	find directories, or you want to find all directories while avoiding to
		580	stat() each entry.
		581
		582	If the system returns type information in readdir, then this is used
		583	to find directories directly. Otherwise, likely directories are files
		584	beginning with ".", or otherwise files with no dots, of which files with
		585	short names are tried first.
		586
		587	=item IO::AIO::READDIR_STAT_ORDER
		588
		589	When this flag is set, then the names will be returned in an order
		590	suitable for stat()'ing each one. That is, when you plan to stat()
		591	all files in the given directory, then the returned order will likely
		592	be fastest.
		593
		594	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		595	the likely dirs come first, resulting in a less optimal stat order.
		596
		597	=item IO::AIO::READDIR_FOUND_UNKNOWN
		598
		599	This flag should not be set when calling C<aio_readdirx>. Instead, it
		600	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		601	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		602	C<$type>'s are known, which can be used to speed up some algorithms.
		603
		604	=back
		605
		606
		607	=item aio_load $path, $data, $callback->($status)
		608
		609	This is a composite request that tries to fully load the given file into
		610	memory. Status is the same as with aio_read.
		611
		612	=cut
		613
		614	sub aio_load($$;$) {
		615	my ($path, undef, $cb) = @_;
		616	my $data = \$_[1];
		617
		618	my $pri = aioreq_pri;
		619	my $grp = aio_group $cb;
		620
		621	aioreq_pri $pri;
		622	add $grp aio_open $path, O_RDONLY, 0, sub {
		623	my $fh = shift
		624	or return $grp->result (-1);
		625
		626	aioreq_pri $pri;
		627	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		628	$grp->result ($_[0]);
		629	};
		630	};
		631
		632	$grp
		633	}
448		634
449	=item aio_copy $srcpath, $dstpath, $callback->($status)	635	=item aio_copy $srcpath, $dstpath, $callback->($status)
450		636
451	Try to copy the I<file> (directories not supported as either source or	637	Try to copy the I<file> (directories not supported as either source or
452	destination) from C<$srcpath> to C<$dstpath> and call the callback with	638	destination) from C<$srcpath> to C<$dstpath> and call the callback with
453	the C<0> (error) or C<-1> ok.	639	a status of C<0> (ok) or C<-1> (error, see C<$!>).
454		640
455	This is a composite request that it creates the destination file with	641	This is a composite request that creates the destination file with
456	mode 0200 and copies the contents of the source file into it using	642	mode 0200 and copies the contents of the source file into it using
457	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	643	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
458	uid/gid, in that order.	644	uid/gid, in that order.
459		645
460	If an error occurs, the partial destination file will be unlinked, if	646	If an error occurs, the partial destination file will be unlinked, if
…		…
462	errors are being ignored.	648	errors are being ignored.
463		649
464	=cut	650	=cut
465		651
466	sub aio_copy($$;$) {	652	sub aio_copy($$;$) {
467	aio_block {
468	my ($src, $dst, $cb) = @_;	653	my ($src, $dst, $cb) = @_;
469		654
470	my $pri = aioreq_pri;	655	my $pri = aioreq_pri;
471	my $grp = aio_group $cb;	656	my $grp = aio_group $cb;
472		657
473	aioreq_pri $pri;	658	aioreq_pri $pri;
474	add $grp aio_open $src, O_RDONLY, 0, sub {	659	add $grp aio_open $src, O_RDONLY, 0, sub {
475	if (my $src_fh = $_[0]) {	660	if (my $src_fh = $_[0]) {
476	my @stat = stat $src_fh;	661	my @stat = stat $src_fh; # hmm, might block over nfs?
477		662
478	aioreq_pri $pri;	663	aioreq_pri $pri;
479	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	664	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
480	if (my $dst_fh = $_[0]) {	665	if (my $dst_fh = $_[0]) {
481	aioreq_pri $pri;	666	aioreq_pri $pri;
482	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	667	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
483	if ($_[0] == $stat[7]) {	668	if ($_[0] == $stat[7]) {
484	$grp->result (0);	669	$grp->result (0);
485	close $src_fh;	670	close $src_fh;
486		671
487	# those should not normally block. should. should.
488	utime $stat[8], $stat[9], $dst;
489	chmod $stat[2] & 07777, $dst_fh;
490	chown $stat[4], $stat[5], $dst_fh;
491	close $dst_fh;
492	} else {	672	my $ch = sub {
493	$grp->result (-1);
494	close $src_fh;
495	close $dst_fh;
496
497	aioreq $pri;	673	aioreq_pri $pri;
		674	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		675	aioreq_pri $pri;
		676	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		677	aioreq_pri $pri;
498	add $grp aio_unlink $dst;	678	add $grp aio_close $dst_fh;
		679	}
		680	};
499	}	681	};
		682
		683	aioreq_pri $pri;
		684	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		685	if ($_[0] < 0 && $! == ENOSYS) {
		686	aioreq_pri $pri;
		687	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
		688	} else {
		689	$ch->();
		690	}
		691	};
		692	} else {
		693	$grp->result (-1);
		694	close $src_fh;
		695	close $dst_fh;
		696
		697	aioreq $pri;
		698	add $grp aio_unlink $dst;
500	};	699	}
501	} else {
502	$grp->result (-1);
503	}	700	};
		701	} else {
		702	$grp->result (-1);
504	},	703	}
505
506	} else {
507	$grp->result (-1);
508	}	704	},
		705
		706	} else {
		707	$grp->result (-1);
509	};	708	}
510
511	$grp
512	}	709	};
		710
		711	$grp
513	}	712	}
514		713
515	=item aio_move $srcpath, $dstpath, $callback->($status)	714	=item aio_move $srcpath, $dstpath, $callback->($status)
516		715
517	Try to move the I<file> (directories not supported as either source or	716	Try to move the I<file> (directories not supported as either source or
518	destination) from C<$srcpath> to C<$dstpath> and call the callback with	717	destination) from C<$srcpath> to C<$dstpath> and call the callback with
519	the C<0> (error) or C<-1> ok.	718	a status of C<0> (ok) or C<-1> (error, see C<$!>).
520		719
521	This is a composite request that tries to rename(2) the file first. If	720	This is a composite request that tries to rename(2) the file first; if
522	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	721	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
523	that is successful, unlinking the C<$srcpath>.	722	that is successful, unlinks the C<$srcpath>.
524		723
525	=cut	724	=cut
526		725
527	sub aio_move($$;$) {	726	sub aio_move($$;$) {
528	aio_block {
529	my ($src, $dst, $cb) = @_;	727	my ($src, $dst, $cb) = @_;
530		728
531	my $pri = aioreq_pri;	729	my $pri = aioreq_pri;
532	my $grp = aio_group $cb;	730	my $grp = aio_group $cb;
533		731
534	aioreq_pri $pri;	732	aioreq_pri $pri;
535	add $grp aio_rename $src, $dst, sub {	733	add $grp aio_rename $src, $dst, sub {
536	if ($_[0] && $! == EXDEV) {	734	if ($_[0] && $! == EXDEV) {
537	aioreq_pri $pri;	735	aioreq_pri $pri;
538	add $grp aio_copy $src, $dst, sub {	736	add $grp aio_copy $src, $dst, sub {
539	$grp->result ($_[0]);
540
541	if (!$_[0]) {
542	aioreq_pri $pri;
543	add $grp aio_unlink $src;
544	}
545	};
546	} else {
547	$grp->result ($_[0]);	737	$grp->result ($_[0]);
		738
		739	if (!$_[0]) {
		740	aioreq_pri $pri;
		741	add $grp aio_unlink $src;
		742	}
548	}	743	};
		744	} else {
		745	$grp->result ($_[0]);
549	};	746	}
550
551	$grp
552	}	747	};
		748
		749	$grp
553	}	750	}
554		751
555	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	752	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
556		753
557	Scans a directory (similar to C<aio_readdir>) but additionally tries to	754	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
577		774
578	Implementation notes.	775	Implementation notes.
579		776
580	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	777	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
581		778
		779	If readdir returns file type information, then this is used directly to
		780	find directories.
		781
582	After reading the directory, the modification time, size etc. of the	782	Otherwise, after reading the directory, the modification time, size etc.
583	directory before and after the readdir is checked, and if they match (and	783	of the directory before and after the readdir is checked, and if they
584	isn't the current time), the link count will be used to decide how many	784	match (and isn't the current time), the link count will be used to decide
585	entries are directories (if >= 2). Otherwise, no knowledge of the number	785	how many entries are directories (if >= 2). Otherwise, no knowledge of the
586	of subdirectories will be assumed.	786	number of subdirectories will be assumed.
587		787
588	Then entries will be sorted into likely directories (everything without	788	Then entries will be sorted into likely directories a non-initial dot
589	a non-initial dot currently) and likely non-directories (everything	789	currently) and likely non-directories (see C<aio_readdirx>). Then every
590	else). Then every entry plus an appended C</.> will be C<stat>'ed,	790	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
591	likely directories first. If that succeeds, it assumes that the entry	791	in order of their inode numbers. If that succeeds, it assumes that the
592	is a directory or a symlink to directory (which will be checked	792	entry is a directory or a symlink to directory (which will be checked
593	seperately). This is often faster than stat'ing the entry itself because	793	seperately). This is often faster than stat'ing the entry itself because
594	filesystems might detect the type of the entry without reading the inode	794	filesystems might detect the type of the entry without reading the inode
595	data (e.g. ext2fs filetype feature).	795	data (e.g. ext2fs filetype feature), even on systems that cannot return
		796	the filetype information on readdir.
596		797
597	If the known number of directories (link count - 2) has been reached, the	798	If the known number of directories (link count - 2) has been reached, the
598	rest of the entries is assumed to be non-directories.	799	rest of the entries is assumed to be non-directories.
599		800
600	This only works with certainty on POSIX (= UNIX) filesystems, which	801	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
604	as those tend to return 0 or 1 as link counts, which disables the	805	as those tend to return 0 or 1 as link counts, which disables the
605	directory counting heuristic.	806	directory counting heuristic.
606		807
607	=cut	808	=cut
608		809
609	sub aio_scandir($$$) {	810	sub aio_scandir($$;$) {
610	aio_block {
611	my ($path, $maxreq, $cb) = @_;	811	my ($path, $maxreq, $cb) = @_;
612		812
613	my $pri = aioreq_pri;	813	my $pri = aioreq_pri;
614		814
615	my $grp = aio_group $cb;	815	my $grp = aio_group $cb;
616		816
617	$maxreq = 4 if $maxreq <= 0;	817	$maxreq = 4 if $maxreq <= 0;
618		818
619	# stat once	819	# stat once
		820	aioreq_pri $pri;
		821	add $grp aio_stat $path, sub {
		822	return $grp->result () if $_[0];
		823	my $now = time;
		824	my $hash1 = join ":", (stat _)[0,1,3,7,9];
		825
		826	# read the directory entries
620	aioreq_pri $pri;	827	aioreq_pri $pri;
621	add $grp aio_stat $path, sub {	828	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
		829	my $entries = shift
622	return $grp->result () if $_[0];	830	or return $grp->result ();
623	my $now = time;
624	my $hash1 = join ":", (stat _)[0,1,3,7,9];
625		831
626	# read the directory entries	832	# stat the dir another time
627	aioreq_pri $pri;	833	aioreq_pri $pri;
628	add $grp aio_readdir $path, sub {
629	my $entries = shift
630	or return $grp->result ();
631
632	# stat the dir another time
633	aioreq_pri $pri;
634	add $grp aio_stat $path, sub {	834	add $grp aio_stat $path, sub {
635	my $hash2 = join ":", (stat _)[0,1,3,7,9];	835	my $hash2 = join ":", (stat _)[0,1,3,7,9];
636		836
637	my $ndirs;	837	my $ndirs;
638		838
639	# take the slow route if anything looks fishy	839	# take the slow route if anything looks fishy
640	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	840	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
641	$ndirs = -1;	841	$ndirs = -1;
642	} else {	842	} else {
643	# if nlink == 2, we are finished	843	# if nlink == 2, we are finished
644	# on non-posix-fs's, we rely on nlink < 2	844	# for non-posix-fs's, we rely on nlink < 2
645	$ndirs = (stat _)[3] - 2	845	$ndirs = (stat _)[3] - 2
646	or return $grp->result ([], $entries);	846	or return $grp->result ([], $entries);
647	}	847	}
648		848
649	# sort into likely dirs and likely nondirs
650	# dirs == files without ".", short entries first
651	$entries = [map $_->[0],
652	sort { $b->[1] cmp $a->[1] }
653	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
654	@$entries];
655
656	my (@dirs, @nondirs);	849	my (@dirs, @nondirs);
657		850
658	my $statgrp = add $grp aio_group sub {	851	my $statgrp = add $grp aio_group sub {
659	$grp->result (\@dirs, \@nondirs);	852	$grp->result (\@dirs, \@nondirs);
660	};	853	};
661		854
662	limit $statgrp $maxreq;	855	limit $statgrp $maxreq;
663	feed $statgrp sub {	856	feed $statgrp sub {
664	return unless @$entries;	857	return unless @$entries;
665	my $entry = pop @$entries;	858	my $entry = shift @$entries;
666		859
667	aioreq_pri $pri;	860	aioreq_pri $pri;
668	add $statgrp aio_stat "$path/$entry/.", sub {	861	add $statgrp aio_stat "$path/$entry/.", sub {
669	if ($_[0] < 0) {	862	if ($_[0] < 0) {
670	push @nondirs, $entry;	863	push @nondirs, $entry;
671	} else {	864	} else {
672	# need to check for real directory	865	# need to check for real directory
673	aioreq_pri $pri;	866	aioreq_pri $pri;
674	add $statgrp aio_lstat "$path/$entry", sub {	867	add $statgrp aio_lstat "$path/$entry", sub {
675	if (-d _) {	868	if (-d _) {
676	push @dirs, $entry;	869	push @dirs, $entry;
677		870
678	unless (--$ndirs) {	871	unless (--$ndirs) {
679	push @nondirs, @$entries;	872	push @nondirs, @$entries;
680	feed $statgrp;	873	feed $statgrp;
681	}
682	} else {
683	push @nondirs, $entry;
684	}	874	}
		875	} else {
		876	push @nondirs, $entry;
685	}	877	}
686	}	878	}
687	};	879	}
688	};	880	};
689	};	881	};
690	};	882	};
691	};	883	};
692
693	$grp
694	}	884	};
		885
		886	$grp
695	}	887	}
		888
		889	=item aio_rmtree $path, $callback->($status)
		890
		891	Delete a directory tree starting (and including) C<$path>, return the
		892	status of the final C<rmdir> only. This is a composite request that
		893	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		894	everything else.
		895
		896	=cut
		897
		898	sub aio_rmtree;
		899	sub aio_rmtree($;$) {
		900	my ($path, $cb) = @_;
		901
		902	my $pri = aioreq_pri;
		903	my $grp = aio_group $cb;
		904
		905	aioreq_pri $pri;
		906	add $grp aio_scandir $path, 0, sub {
		907	my ($dirs, $nondirs) = @_;
		908
		909	my $dirgrp = aio_group sub {
		910	add $grp aio_rmdir $path, sub {
		911	$grp->result ($_[0]);
		912	};
		913	};
		914
		915	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		916	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		917
		918	add $grp $dirgrp;
		919	};
		920
		921	$grp
		922	}
		923
		924	=item aio_sync $callback->($status)
		925
		926	Asynchronously call sync and call the callback when finished.
696		927
697	=item aio_fsync $fh, $callback->($status)	928	=item aio_fsync $fh, $callback->($status)
698		929
699	Asynchronously call fsync on the given filehandle and call the callback	930	Asynchronously call fsync on the given filehandle and call the callback
700	with the fsync result code.	931	with the fsync result code.
…		…
704	Asynchronously call fdatasync on the given filehandle and call the	935	Asynchronously call fdatasync on the given filehandle and call the
705	callback with the fdatasync result code.	936	callback with the fdatasync result code.
706		937
707	If this call isn't available because your OS lacks it or it couldn't be	938	If this call isn't available because your OS lacks it or it couldn't be
708	detected, it will be emulated by calling C<fsync> instead.	939	detected, it will be emulated by calling C<fsync> instead.
		940
		941	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		942
		943	Sync the data portion of the file specified by C<$offset> and C<$length>
		944	to disk (but NOT the metadata), by calling the Linux-specific
		945	sync_file_range call. If sync_file_range is not available or it returns
		946	ENOSYS, then fdatasync or fsync is being substituted.
		947
		948	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		949	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		950	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		951	manpage for details.
		952
		953	=item aio_pathsync $path, $callback->($status)
		954
		955	This request tries to open, fsync and close the given path. This is a
		956	composite request intended to sync directories after directory operations
		957	(E.g. rename). This might not work on all operating systems or have any
		958	specific effect, but usually it makes sure that directory changes get
		959	written to disc. It works for anything that can be opened for read-only,
		960	not just directories.
		961
		962	Future versions of this function might fall back to other methods when
		963	C<fsync> on the directory fails (such as calling C<sync>).
		964
		965	Passes C<0> when everything went ok, and C<-1> on error.
		966
		967	=cut
		968
		969	sub aio_pathsync($;$) {
		970	my ($path, $cb) = @_;
		971
		972	my $pri = aioreq_pri;
		973	my $grp = aio_group $cb;
		974
		975	aioreq_pri $pri;
		976	add $grp aio_open $path, O_RDONLY, 0, sub {
		977	my ($fh) = @_;
		978	if ($fh) {
		979	aioreq_pri $pri;
		980	add $grp aio_fsync $fh, sub {
		981	$grp->result ($_[0]);
		982
		983	aioreq_pri $pri;
		984	add $grp aio_close $fh;
		985	};
		986	} else {
		987	$grp->result (-1);
		988	}
		989	};
		990
		991	$grp
		992	}
709		993
710	=item aio_group $callback->(...)	994	=item aio_group $callback->(...)
711		995
712	This is a very special aio request: Instead of doing something, it is a	996	This is a very special aio request: Instead of doing something, it is a
713	container for other aio requests, which is useful if you want to bundle	997	container for other aio requests, which is useful if you want to bundle
…		…
763	=item cancel $req	1047	=item cancel $req
764		1048
765	Cancels the request, if possible. Has the effect of skipping execution	1049	Cancels the request, if possible. Has the effect of skipping execution
766	when entering the B<execute> state and skipping calling the callback when	1050	when entering the B<execute> state and skipping calling the callback when
767	entering the the B<result> state, but will leave the request otherwise	1051	entering the the B<result> state, but will leave the request otherwise
768	untouched. That means that requests that currently execute will not be	1052	untouched (with the exception of readdir). That means that requests that
769	stopped and resources held by the request will not be freed prematurely.	1053	currently execute will not be stopped and resources held by the request
		1054	will not be freed prematurely.
770		1055
771	=item cb $req $callback->(...)	1056	=item cb $req $callback->(...)
772		1057
773	Replace (or simply set) the callback registered to the request.	1058	Replace (or simply set) the callback registered to the request.
774		1059
…		…
825	Their lifetime, simplified, looks like this: when they are empty, they	1110	Their lifetime, simplified, looks like this: when they are empty, they
826	will finish very quickly. If they contain only requests that are in the	1111	will finish very quickly. If they contain only requests that are in the
827	C<done> state, they will also finish. Otherwise they will continue to	1112	C<done> state, they will also finish. Otherwise they will continue to
828	exist.	1113	exist.
829		1114
830	That means after creating a group you have some time to add requests. And	1115	That means after creating a group you have some time to add requests
831	in the callbacks of those requests, you can add further requests to the	1116	(precisely before the callback has been invoked, which is only done within
832	group. And only when all those requests have finished will the the group	1117	the C<poll_cb>). And in the callbacks of those requests, you can add
833	itself finish.	1118	further requests to the group. And only when all those requests have
		1119	finished will the the group itself finish.
834		1120
835	=over 4	1121	=over 4
836		1122
837	=item add $grp ...	1123	=item add $grp ...
838		1124
…		…
850	itself. Useful when you queued a lot of events but got a result early.	1136	itself. Useful when you queued a lot of events but got a result early.
851		1137
852	=item $grp->result (...)	1138	=item $grp->result (...)
853		1139
854	Set the result value(s) that will be passed to the group callback when all	1140	Set the result value(s) that will be passed to the group callback when all
855	subrequests have finished and set thre groups errno to the current value	1141	subrequests have finished and set the groups errno to the current value
856	of errno (just like calling C<errno> without an error number). By default,	1142	of errno (just like calling C<errno> without an error number). By default,
857	no argument will be passed and errno is zero.	1143	no argument will be passed and errno is zero.
858		1144
859	=item $grp->errno ([$errno])	1145	=item $grp->errno ([$errno])
860		1146
…		…
871	=item feed $grp $callback->($grp)	1157	=item feed $grp $callback->($grp)
872		1158
873	Sets a feeder/generator on this group: every group can have an attached	1159	Sets a feeder/generator on this group: every group can have an attached
874	generator that generates requests if idle. The idea behind this is that,	1160	generator that generates requests if idle. The idea behind this is that,
875	although you could just queue as many requests as you want in a group,	1161	although you could just queue as many requests as you want in a group,
876	this might starve other requests for a potentially long time. For	1162	this might starve other requests for a potentially long time. For example,
877	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1163	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
878	requests, delaying any later requests for a long time.	1164	delaying any later requests for a long time.
879		1165
880	To avoid this, and allow incremental generation of requests, you can	1166	To avoid this, and allow incremental generation of requests, you can
881	instead a group and set a feeder on it that generates those requests. The	1167	instead a group and set a feeder on it that generates those requests. The
882	feed callback will be called whenever there are few enough (see C<limit>,	1168	feed callback will be called whenever there are few enough (see C<limit>,
883	below) requests active in the group itself and is expected to queue more	1169	below) requests active in the group itself and is expected to queue more
…		…
887	not impose any limits).	1173	not impose any limits).
888		1174
889	If the feed does not queue more requests when called, it will be	1175	If the feed does not queue more requests when called, it will be
890	automatically removed from the group.	1176	automatically removed from the group.
891		1177
892	If the feed limit is C<0>, it will be set to C<2> automatically.	1178	If the feed limit is C<0> when this method is called, it will be set to
		1179	C<2> automatically.
893		1180
894	Example:	1181	Example:
895		1182
896	# stat all files in @files, but only ever use four aio requests concurrently:	1183	# stat all files in @files, but only ever use four aio requests concurrently:
897		1184
…		…
909	Sets the feeder limit for the group: The feeder will be called whenever	1196	Sets the feeder limit for the group: The feeder will be called whenever
910	the group contains less than this many requests.	1197	the group contains less than this many requests.
911		1198
912	Setting the limit to C<0> will pause the feeding process.	1199	Setting the limit to C<0> will pause the feeding process.
913		1200
		1201	The default value for the limit is C<0>, but note that setting a feeder
		1202	automatically bumps it up to C<2>.
		1203
914	=back	1204	=back
915		1205
916	=head2 SUPPORT FUNCTIONS	1206	=head2 SUPPORT FUNCTIONS
917		1207
918	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1208	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
920	=over 4	1210	=over 4
921		1211
922	=item $fileno = IO::AIO::poll_fileno	1212	=item $fileno = IO::AIO::poll_fileno
923		1213
924	Return the I<request result pipe file descriptor>. This filehandle must be	1214	Return the I<request result pipe file descriptor>. This filehandle must be
925	polled for reading by some mechanism outside this module (e.g. Event or	1215	polled for reading by some mechanism outside this module (e.g. EV, Glib,
926	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1216	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
927	to call C<poll_cb> to check the results.	1217	you have to call C<poll_cb> to check the results.
928		1218
929	See C<poll_cb> for an example.	1219	See C<poll_cb> for an example.
930		1220
931	=item IO::AIO::poll_cb	1221	=item IO::AIO::poll_cb
932		1222
933	Process some outstanding events on the result pipe. You have to call this	1223	Process some outstanding events on the result pipe. You have to call this
934	regularly. Returns the number of events processed. Returns immediately	1224	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1225	returned earlier for whatever reason. Returns immediately when no events
935	when no events are outstanding. The amount of events processed depends on	1226	are outstanding. The amount of events processed depends on the settings of
936	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1227	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
937		1228
938	If not all requests were processed for whatever reason, the filehandle	1229	If not all requests were processed for whatever reason, the filehandle
939	will still be ready when C<poll_cb> returns.	1230	will still be ready when C<poll_cb> returns, so normally you don't have to
		1231	do anything special to have it called later.
940		1232
941	Example: Install an Event watcher that automatically calls	1233	Example: Install an Event watcher that automatically calls
942	IO::AIO::poll_cb with high priority:	1234	IO::AIO::poll_cb with high priority (more examples can be found in the
		1235	SYNOPSIS section, at the top of this document):
943		1236
944	Event->io (fd => IO::AIO::poll_fileno,	1237	Event->io (fd => IO::AIO::poll_fileno,
945	poll => 'r', async => 1,	1238	poll => 'r', async => 1,
946	cb => \&IO::AIO::poll_cb);	1239	cb => \&IO::AIO::poll_cb);
947		1240
…		…
1003	Strictly equivalent to:	1296	Strictly equivalent to:
1004		1297
1005	IO::AIO::poll_wait, IO::AIO::poll_cb	1298	IO::AIO::poll_wait, IO::AIO::poll_cb
1006	while IO::AIO::nreqs;	1299	while IO::AIO::nreqs;
1007		1300
		1301	=back
		1302
1008	=head3 CONTROLLING THE NUMBER OF THREADS	1303	=head3 CONTROLLING THE NUMBER OF THREADS
		1304
		1305	=over
1009		1306
1010	=item IO::AIO::min_parallel $nthreads	1307	=item IO::AIO::min_parallel $nthreads
1011		1308
1012	Set the minimum number of AIO threads to C<$nthreads>. The current	1309	Set the minimum number of AIO threads to C<$nthreads>. The current
1013	default is C<8>, which means eight asynchronous operations can execute	1310	default is C<8>, which means eight asynchronous operations can execute
…		…
1054		1351
1055	The default is probably ok in most situations, especially if thread	1352	The default is probably ok in most situations, especially if thread
1056	creation is fast. If thread creation is very slow on your system you might	1353	creation is fast. If thread creation is very slow on your system you might
1057	want to use larger values.	1354	want to use larger values.
1058		1355
1059	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1356	=item IO::AIO::max_outstanding $maxreqs
1060		1357
1061	This is a very bad function to use in interactive programs because it	1358	This is a very bad function to use in interactive programs because it
1062	blocks, and a bad way to reduce concurrency because it is inexact: Better	1359	blocks, and a bad way to reduce concurrency because it is inexact: Better
1063	use an C<aio_group> together with a feed callback.	1360	use an C<aio_group> together with a feed callback.
1064		1361
1065	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1362	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1066	to queue up more than this number of requests, the next call to the	1363	do queue up more than this number of requests, the next call to the
1067	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1364	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1068	function will block until the limit is no longer exceeded.	1365	function will block until the limit is no longer exceeded.
1069		1366
1070	The default value is very large, so there is no practical limit on the	1367	The default value is very large, so there is no practical limit on the
1071	number of outstanding requests.	1368	number of outstanding requests.
1072		1369
1073	You can still queue as many requests as you want. Therefore,	1370	You can still queue as many requests as you want. Therefore,
1074	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1371	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1075	as a stop gap to shield against fatal memory overflow (with large values).	1372	as a stop gap to shield against fatal memory overflow (with large values).
1076		1373
		1374	=back
		1375
1077	=head3 STATISTICAL INFORMATION	1376	=head3 STATISTICAL INFORMATION
		1377
		1378	=over
1078		1379
1079	=item IO::AIO::nreqs	1380	=item IO::AIO::nreqs
1080		1381
1081	Returns the number of requests currently in the ready, execute or pending	1382	Returns the number of requests currently in the ready, execute or pending
1082	states (i.e. for which their callback has not been invoked yet).	1383	states (i.e. for which their callback has not been invoked yet).
…		…
1096	Returns the number of requests currently in the pending state (executed,	1397	Returns the number of requests currently in the pending state (executed,
1097	but not yet processed by poll_cb).	1398	but not yet processed by poll_cb).
1098		1399
1099	=back	1400	=back
1100		1401
		1402	=head3 MISCELLANEOUS FUNCTIONS
		1403
		1404	IO::AIO implements some functions that might be useful, but are not
		1405	asynchronous.
		1406
		1407	=over 4
		1408
		1409	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1410
		1411	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1412	but is blocking (this makes most sense if you know the input data is
		1413	likely cached already and the output filehandle is set to non-blocking
		1414	operations).
		1415
		1416	Returns the number of bytes copied, or C<-1> on error.
		1417
		1418	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1419
		1420	Simply calls the C<posix_fadvise> function (see it's
		1421	manpage for details). The following advice constants are
		1422	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1423	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1424	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1425
		1426	On systems that do not implement C<posix_fadvise>, this function returns
		1427	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1428
		1429	=back
		1430
1101	=cut	1431	=cut
1102
1103	# support function to convert a fd into a perl filehandle
1104	sub _fd2fh {
1105	return undef if $_[0] < 0;
1106
1107	# try to generate nice filehandles
1108	my $sym = "IO::AIO::fd#$_[0]";
1109	local *$sym;
1110
1111	open *$sym, "+<&=$_[0]" # usually works under any unix
1112	or open *$sym, "<&=$_[0]" # cygwin needs this
1113	or open *$sym, ">&=$_[0]" # or this
1114	or return undef;
1115
1116	*$sym
1117	}
1118		1432
1119	min_parallel 8;	1433	min_parallel 8;
1120		1434
1121	END { flush }	1435	END { flush }
1122		1436
…		…
1146	bytes of memory. In addition, stat requests need a stat buffer (possibly	1460	bytes of memory. In addition, stat requests need a stat buffer (possibly
1147	a few hundred bytes), readdir requires a result buffer and so on. Perl	1461	a few hundred bytes), readdir requires a result buffer and so on. Perl
1148	scalars and other data passed into aio requests will also be locked and	1462	scalars and other data passed into aio requests will also be locked and
1149	will consume memory till the request has entered the done state.	1463	will consume memory till the request has entered the done state.
1150		1464
1151	This is now awfully much, so queuing lots of requests is not usually a	1465	This is not awfully much, so queuing lots of requests is not usually a
1152	problem.	1466	problem.
1153		1467
1154	Per-thread usage:	1468	Per-thread usage:
1155		1469
1156	In the execution phase, some aio requests require more memory for	1470	In the execution phase, some aio requests require more memory for
…		…
1161		1475
1162	Known bugs will be fixed in the next release.	1476	Known bugs will be fixed in the next release.
1163		1477
1164	=head1 SEE ALSO	1478	=head1 SEE ALSO
1165		1479
1166	L<Coro::AIO>.	1480	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1481	more natural syntax.
1167		1482
1168	=head1 AUTHOR	1483	=head1 AUTHOR
1169		1484
1170	Marc Lehmann <schmorp@schmorp.de>	1485	Marc Lehmann <schmorp@schmorp.de>
1171	http://home.schmorp.de/	1486	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.96 by root, Fri Dec 22 04:05:50 2006 UTC vs. Revision 1.167 by root, Thu Nov 12 01:15:36 2009 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.96 by root, Fri Dec 22 04:05:50 2006 UTC vs.
Revision 1.167 by root, Thu Nov 12 01:15:36 2009 UTC