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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs.
Revision 1.161 by root, Tue Jul 14 00:32:27 2009 UTC

…		…
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
25	$req->cancel; # cancel request if still in queue	26	$req->cancel; # cancel request if still in queue
26		27
27	my $grp = aio_group sub { print "all stats done\n" };	28	my $grp = aio_group sub { print "all stats done\n" };
28	add $grp aio_stat "..." for ...;	29	add $grp aio_stat "..." for ...;
29		30
		31	# AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
		32	use AnyEvent::AIO;
		33
30	# AnyEvent integration	34	# EV integration
31	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;
32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33		36
34	# Event integration	37	# Event integration
35	Event->io (fd => IO::AIO::poll_fileno,	38	Event->io (fd => IO::AIO::poll_fileno,
36	poll => 'r',	39	poll => 'r',
37	cb => \&IO::AIO::poll_cb);	40	cb => \&IO::AIO::poll_cb);
…		…
49	\&IO::AIO::poll_cb);	52	\&IO::AIO::poll_cb);
50		53
51	=head1 DESCRIPTION	54	=head1 DESCRIPTION
52		55
53	This module implements asynchronous I/O using whatever means your	56	This module implements asynchronous I/O using whatever means your
54	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>).
55		59
56	Asynchronous means that operations that can normally block your program	60	Asynchronous means that operations that can normally block your program
57	(e.g. reading from disk) will be done asynchronously: the operation	61	(e.g. reading from disk) will be done asynchronously: the operation
58	will still block, but you can do something else in the meantime. This	62	will still block, but you can do something else in the meantime. This
59	is extremely useful for programs that need to stay interactive even	63	is extremely useful for programs that need to stay interactive even
…		…
61	etc.), but can also be used to easily do operations in parallel that are	65	etc.), but can also be used to easily do operations in parallel that are
62	normally done sequentially, e.g. stat'ing many files, which is much faster	66	normally done sequentially, e.g. stat'ing many files, which is much faster
63	on a RAID volume or over NFS when you do a number of stat operations	67	on a RAID volume or over NFS when you do a number of stat operations
64	concurrently.	68	concurrently.
65		69
66	While this works on all types of file descriptors (for example sockets),	70	While most of this works on all types of file descriptors (for
67	using these functions on file descriptors that support nonblocking	71	example sockets), using these functions on file descriptors that
68	operation (again, sockets, pipes etc.) is very inefficient. Use an event	72	support nonblocking operation (again, sockets, pipes etc.) is
69	loop for that (such as the L<Event\|Event> module): IO::AIO will naturally	73	very inefficient. Use an event loop for that (such as the L<EV>
70	fit into such an event loop itself.	74	module): IO::AIO will naturally fit into such an event loop itself.
71		75
72	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
73	requests and signal their completion. You don't need thread support	77	requests and signal their completion. You don't need thread support
74	in perl, and the threads created by this module will not be visible	78	in perl, and the threads created by this module will not be visible
75	to perl. In the future, this module might make use of the native aio	79	to perl. In the future, this module might make use of the native aio
…		…
77	not well-supported or restricted (GNU/Linux doesn't allow them on normal	81	not well-supported or restricted (GNU/Linux doesn't allow them on normal
78	files currently, for example), and they would only support aio_read and	82	files currently, for example), and they would only support aio_read and
79	aio_write, so the remaining functionality would have to be implemented	83	aio_write, so the remaining functionality would have to be implemented
80	using threads anyway.	84	using threads anyway.
81		85
82	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,
83	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
84	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
85	never call C<poll_cb> (or other C<aio_> functions) recursively.	89	call C<poll_cb> (or other C<aio_> functions) recursively.
86		90
87	=head2 EXAMPLE	91	=head2 EXAMPLE
88		92
89	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
90	F</etc/passwd> asynchronously:	94	F</etc/passwd> asynchronously:
91		95
92	use Fcntl;	96	use Fcntl;
93	use Event;	97	use EV;
94	use IO::AIO;	98	use IO::AIO;
95		99
96	# register the IO::AIO callback with Event	100	# register the IO::AIO callback with EV
97	Event->io (fd => IO::AIO::poll_fileno,	101	my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
98	poll => 'r',
99	cb => \&IO::AIO::poll_cb);
100		102
101	# queue the request to open /etc/passwd	103	# queue the request to open /etc/passwd
102	aio_open "/etc/passwd", O_RDONLY, 0, sub {	104	aio_open "/etc/passwd", O_RDONLY, 0, sub {
103	my $fh = $_[0]	105	my $fh = shift
104	or die "error while opening: $!";	106	or die "error while opening: $!";
105		107
106	# stat'ing filehandles is generally non-blocking	108	# stat'ing filehandles is generally non-blocking
107	my $size = -s $fh;	109	my $size = -s $fh;
108		110
…		…
116		118
117	# file contents now in $contents	119	# file contents now in $contents
118	print $contents;	120	print $contents;
119		121
120	# exit event loop and program	122	# exit event loop and program
121	Event::unloop;	123	EV::unloop;
122	};	124	};
123	};	125	};
124		126
125	# possibly queue up other requests, or open GUI windows,	127	# possibly queue up other requests, or open GUI windows,
126	# check for sockets etc. etc.	128	# check for sockets etc. etc.
127		129
128	# process events as long as there are some:	130	# process events as long as there are some:
129	Event::loop;	131	EV::loop;
130		132
131	=head1 REQUEST ANATOMY AND LIFETIME	133	=head1 REQUEST ANATOMY AND LIFETIME
132		134
133	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
134	directly visible to Perl.	136	directly visible to Perl.
…		…
176	Request has reached the end of its lifetime and holds no resources anymore	178	Request has reached the end of its lifetime and holds no resources anymore
177	(except possibly for the Perl object, but its connection to the actual	179	(except possibly for the Perl object, but its connection to the actual
178	aio request is severed and calling its methods will either do nothing or	180	aio request is severed and calling its methods will either do nothing or
179	result in a runtime error).	181	result in a runtime error).
180		182
		183	=back
		184
181	=cut	185	=cut
182		186
183	package IO::AIO;	187	package IO::AIO;
184		188
185	no warnings;	189	use Carp ();
186	use strict 'vars';	190
		191	use common::sense;
187		192
188	use base 'Exporter';	193	use base 'Exporter';
189		194
190	BEGIN {	195	BEGIN {
191	our $VERSION = '2.1';	196	our $VERSION = '3.261';
192		197
193	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
194	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
195	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	200	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
196	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
197	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	206	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
198	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	207	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
199	min_parallel max_parallel max_idle	208	min_parallel max_parallel max_idle
200	nreqs nready npending nthreads	209	nreqs nready npending nthreads
201	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
202		214
203	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	215	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
204		216
205	require XSLoader;	217	require XSLoader;
206	XSLoader::load ("IO::AIO", $VERSION);	218	XSLoader::load ("IO::AIO", $VERSION);
207	}	219	}
208		220
209	=head1 FUNCTIONS	221	=head1 FUNCTIONS
210		222
211	=head2 AIO FUNCTIONS	223	=head2 AIO REQUEST FUNCTIONS
212		224
213	All the C<aio_*> calls are more or less thin wrappers around the syscall	225	All the C<aio_*> calls are more or less thin wrappers around the syscall
214	with the same name (sans C<aio_>). The arguments are similar or identical,	226	with the same name (sans C<aio_>). The arguments are similar or identical,
215	and they all accept an additional (and optional) C<$callback> argument	227	and they all accept an additional (and optional) C<$callback> argument
216	which must be a code reference. This code reference will get called with	228	which must be a code reference. This code reference will get called with
217	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	229	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
218	perl, which usually delivers "false") as it's sole argument when the given	230	perl, which usually delivers "false") as its sole argument after the given
219	syscall has been executed asynchronously.	231	syscall has been executed asynchronously.
220		232
221	All functions expecting a filehandle keep a copy of the filehandle	233	All functions expecting a filehandle keep a copy of the filehandle
222	internally until the request has finished.	234	internally until the request has finished.
223		235
224	All requests return objects of type L<IO::AIO::REQ> that allow further	236	All functions return request objects of type L<IO::AIO::REQ> that allow
225	manipulation of those requests while they are in-flight.	237	further manipulation of those requests while they are in-flight.
226		238
227	The pathnames you pass to these routines I<must> be absolute and	239	The pathnames you pass to these routines I<must> be absolute and
228	encoded in byte form. The reason for the former is that at the time the	240	encoded as octets. The reason for the former is that at the time the
229	request is being executed, the current working directory could have	241	request is being executed, the current working directory could have
230	changed. Alternatively, you can make sure that you never change the	242	changed. Alternatively, you can make sure that you never change the
231	current working directory.	243	current working directory anywhere in the program and then use relative
		244	paths.
232		245
233	To encode pathnames to byte form, either make sure you either: a)	246	To encode pathnames as octets, either make sure you either: a) always pass
234	always pass in filenames you got from outside (command line, readdir	247	in filenames you got from outside (command line, readdir etc.) without
235	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	248	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
236	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
237	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)
238	use something else.	251	use something else to ensure your scalar has the correct contents.
		252
		253	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		254	handles correctly whether it is set or not.
239		255
240	=over 4	256	=over 4
241		257
242	=item $prev_pri = aioreq_pri [$pri]	258	=item $prev_pri = aioreq_pri [$pri]
243		259
…		…
263	aio_read $_[0], ..., sub {	279	aio_read $_[0], ..., sub {
264	...	280	...
265	};	281	};
266	};	282	};
267		283
		284
268	=item aioreq_nice $pri_adjust	285	=item aioreq_nice $pri_adjust
269		286
270	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
271	priority, so effects are cumulative.	288	priority, so the effect is cumulative.
		289
272		290
273	=item aio_open $pathname, $flags, $mode, $callback->($fh)	291	=item aio_open $pathname, $flags, $mode, $callback->($fh)
274		292
275	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
276	created filehandle for the file.	294	created filehandle for the file.
…		…
282	list. They are the same as used by C<sysopen>.	300	list. They are the same as used by C<sysopen>.
283		301
284	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
285	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>,
286	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,
287	and C<0666> or C<0777> if you do).	305	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		306	by the umask in effect then the request is being executed, so better never
		307	change the umask.
288		308
289	Example:	309	Example:
290		310
291	aio_open "/etc/passwd", O_RDONLY, 0, sub {	311	aio_open "/etc/passwd", O_RDONLY, 0, sub {
292	if ($_[0]) {	312	if ($_[0]) {
…		…
295	} else {	315	} else {
296	die "open failed: $!\n";	316	die "open failed: $!\n";
297	}	317	}
298	};	318	};
299		319
		320
300	=item aio_close $fh, $callback->($status)	321	=item aio_close $fh, $callback->($status)
301		322
302	Asynchronously close a file and call the callback with the result	323	Asynchronously close a file and call the callback with the result
303	code. I<WARNING:> although accepted, you should not pass in a perl	324	code.
304	filehandle here, as perl will likely close the file descriptor another
305	time when the filehandle is destroyed. Normally, you can safely call perls
306	C<close> or just let filehandles go out of scope.
307		325
308	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
309	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
310		337
311	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	338	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
312		339
313	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	340	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
314		341
315	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
316	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<$dataoffset>
317	callback without the actual number of bytes read (or -1 on error, just	344	and calls the callback without the actual number of bytes read (or -1 on
318	like the syscall).	345	error, just like the syscall).
		346
		347	C<aio_read> will, like C<sysread>, shrink or grow the C<$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<$data>.
319		359
320	The C<$data> scalar I<MUST NOT> be modified in any way while the request	360	The C<$data> scalar I<MUST NOT> be modified in any way while the request
321	is outstanding. Modifying it can result in segfaults or WW3 (if the	361	is outstanding. Modifying it can result in segfaults or World War III (if
322	necessary/optional hardware is installed).	362	the necessary/optional hardware is installed).
323		363
324	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	364	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
325	offset C<0> within the scalar:	365	offset C<0> within the scalar:
326		366
327	aio_read $fh, 7, 15, $buffer, 0, sub {	367	aio_read $fh, 7, 15, $buffer, 0, sub {
328	$_[0] > 0 or die "read error: $!";	368	$_[0] > 0 or die "read error: $!";
329	print "read $_[0] bytes: <$buffer>\n";	369	print "read $_[0] bytes: <$buffer>\n";
330	};	370	};
		371
331		372
332	=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)
333		374
334	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
335	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
…		…
349	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
350	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
351	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
352	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
353	read.	394	read.
		395
354		396
355	=item aio_readahead $fh,$offset,$length, $callback->($retval)	397	=item aio_readahead $fh,$offset,$length, $callback->($retval)
356		398
357	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
358	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>
…		…
364	file. The current file offset of the file is left unchanged.	406	file. The current file offset of the file is left unchanged.
365		407
366	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
367	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.
368		410
		411
369	=item aio_stat $fh_or_path, $callback->($status)	412	=item aio_stat $fh_or_path, $callback->($status)
370		413
371	=item aio_lstat $fh, $callback->($status)	414	=item aio_lstat $fh, $callback->($status)
372		415
373	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
…		…
386	aio_stat "/etc/passwd", sub {	429	aio_stat "/etc/passwd", sub {
387	$_[0] and die "stat failed: $!";	430	$_[0] and die "stat failed: $!";
388	print "size is ", -s _, "\n";	431	print "size is ", -s _, "\n";
389	};	432	};
390		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
391	=item aio_unlink $pathname, $callback->($status)	476	=item aio_unlink $pathname, $callback->($status)
392		477
393	Asynchronously unlink (delete) a file and call the callback with the	478	Asynchronously unlink (delete) a file and call the callback with the
394	result code.	479	result code.
395		480
		481
396	=item aio_mknod $path, $mode, $dev, $callback->($status)	482	=item aio_mknod $path, $mode, $dev, $callback->($status)
397		483
398	[EXPERIMENTAL]	484	[EXPERIMENTAL]
399		485
400	Asynchronously create a device node (or fifo). See mknod(2).	486	Asynchronously create a device node (or fifo). See mknod(2).
401		487
402	The only (POSIX-) portable way of calling this function is:	488	The only (POSIX-) portable way of calling this function is:
403		489
404	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	490	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		491
405		492
406	=item aio_link $srcpath, $dstpath, $callback->($status)	493	=item aio_link $srcpath, $dstpath, $callback->($status)
407		494
408	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
409	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.
410		497
		498
411	=item aio_symlink $srcpath, $dstpath, $callback->($status)	499	=item aio_symlink $srcpath, $dstpath, $callback->($status)
412		500
413	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
414	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.
415		503
		504
		505	=item aio_readlink $path, $callback->($link)
		506
		507	Asynchronously read the symlink specified by C<$path> and pass it to
		508	the callback. If an error occurs, nothing or undef gets passed to the
		509	callback.
		510
		511
416	=item aio_rename $srcpath, $dstpath, $callback->($status)	512	=item aio_rename $srcpath, $dstpath, $callback->($status)
417		513
418	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
419	rename(2) and call the callback with the result code.	515	rename(2) and call the callback with the result code.
420		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
421	=item aio_rmdir $pathname, $callback->($status)	525	=item aio_rmdir $pathname, $callback->($status)
422		526
423	Asynchronously rmdir (delete) a directory and call the callback with the	527	Asynchronously rmdir (delete) a directory and call the callback with the
424	result code.	528	result code.
		529
425		530
426	=item aio_readdir $pathname, $callback->($entries)	531	=item aio_readdir $pathname, $callback->($entries)
427		532
428	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
429	directory (i.e. opendir + readdir + closedir). The entries will not be	534	directory (i.e. opendir + readdir + closedir). The entries will not be
430	sorted, and will B<NOT> include the C<.> and C<..> entries.	535	sorted, and will B<NOT> include the C<.> and C<..> entries.
431		536
432	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
433	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	}
434		634
435	=item aio_copy $srcpath, $dstpath, $callback->($status)	635	=item aio_copy $srcpath, $dstpath, $callback->($status)
436		636
437	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
438	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
439	the C<0> (error) or C<-1> ok.	639	the C<0> (error) or C<-1> ok.
440		640
441	This is a composite request that it creates the destination file with	641	This is a composite request that creates the destination file with
442	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
443	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	643	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
444	uid/gid, in that order.	644	uid/gid, in that order.
445		645
446	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
…		…
456	my $grp = aio_group $cb;	656	my $grp = aio_group $cb;
457		657
458	aioreq_pri $pri;	658	aioreq_pri $pri;
459	add $grp aio_open $src, O_RDONLY, 0, sub {	659	add $grp aio_open $src, O_RDONLY, 0, sub {
460	if (my $src_fh = $_[0]) {	660	if (my $src_fh = $_[0]) {
461	my @stat = stat $src_fh;	661	my @stat = stat $src_fh; # hmm, might bock over nfs?
462		662
463	aioreq_pri $pri;	663	aioreq_pri $pri;
464	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 {
465	if (my $dst_fh = $_[0]) {	665	if (my $dst_fh = $_[0]) {
466	aioreq_pri $pri;	666	aioreq_pri $pri;
467	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	667	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
468	if ($_[0] == $stat[7]) {	668	if ($_[0] == $stat[7]) {
469	$grp->result (0);	669	$grp->result (0);
470	close $src_fh;	670	close $src_fh;
471		671
472	# those should not normally block. should. should.	672	my $ch = sub {
		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;
		678	add $grp aio_close $dst_fh;
		679	}
		680	};
		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;
473	utime $stat[8], $stat[9], $dst;	687	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
474	chmod $stat[2] & 07777, $dst_fh;	688	} else {
475	chown $stat[4], $stat[5], $dst_fh;	689	$ch->();
		690	}
476	close $dst_fh;	691	};
477	} else {	692	} else {
478	$grp->result (-1);	693	$grp->result (-1);
479	close $src_fh;	694	close $src_fh;
480	close $dst_fh;	695	close $dst_fh;
481		696
…		…
500		715
501	Try to move the I<file> (directories not supported as either source or	716	Try to move the I<file> (directories not supported as either source or
502	destination) from C<$srcpath> to C<$dstpath> and call the callback with	717	destination) from C<$srcpath> to C<$dstpath> and call the callback with
503	the C<0> (error) or C<-1> ok.	718	the C<0> (error) or C<-1> ok.
504		719
505	This is a composite request that tries to rename(2) the file first. If	720	This is a composite request that tries to rename(2) the file first; if
506	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	721	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
507	that is successful, unlinking the C<$srcpath>.	722	that is successful, unlinks the C<$srcpath>.
508		723
509	=cut	724	=cut
510		725
511	sub aio_move($$;$) {	726	sub aio_move($$;$) {
512	my ($src, $dst, $cb) = @_;	727	my ($src, $dst, $cb) = @_;
…		…
559		774
560	Implementation notes.	775	Implementation notes.
561		776
562	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.
563		778
		779	If readdir returns file type information, then this is used directly to
		780	find directories.
		781
564	After reading the directory, the modification time, size etc. of the	782	Otherwise, after reading the directory, the modification time, size etc.
565	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
566	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
567	entries are directories (if >= 2). Otherwise, no knowledge of the number	785	how many entries are directories (if >= 2). Otherwise, no knowledge of the
568	of subdirectories will be assumed.	786	number of subdirectories will be assumed.
569		787
570	Then entries will be sorted into likely directories (everything without	788	Then entries will be sorted into likely directories a non-initial dot
571	a non-initial dot currently) and likely non-directories (everything	789	currently) and likely non-directories (see C<aio_readdirx>). Then every
572	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,
573	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
574	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
575	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
576	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
577	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.
578		797
579	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
580	rest of the entries is assumed to be non-directories.	799	rest of the entries is assumed to be non-directories.
581		800
582	This only works with certainty on POSIX (= UNIX) filesystems, which	801	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
586	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
587	directory counting heuristic.	806	directory counting heuristic.
588		807
589	=cut	808	=cut
590		809
591	sub aio_scandir($$$) {	810	sub aio_scandir($$;$) {
592	my ($path, $maxreq, $cb) = @_;	811	my ($path, $maxreq, $cb) = @_;
593		812
594	my $pri = aioreq_pri;	813	my $pri = aioreq_pri;
595		814
596	my $grp = aio_group $cb;	815	my $grp = aio_group $cb;
…		…
604	my $now = time;	823	my $now = time;
605	my $hash1 = join ":", (stat _)[0,1,3,7,9];	824	my $hash1 = join ":", (stat _)[0,1,3,7,9];
606		825
607	# read the directory entries	826	# read the directory entries
608	aioreq_pri $pri;	827	aioreq_pri $pri;
609	add $grp aio_readdir $path, sub {	828	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
610	my $entries = shift	829	my $entries = shift
611	or return $grp->result ();	830	or return $grp->result ();
612		831
613	# stat the dir another time	832	# stat the dir another time
614	aioreq_pri $pri;	833	aioreq_pri $pri;
…		…
620	# take the slow route if anything looks fishy	839	# take the slow route if anything looks fishy
621	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	840	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
622	$ndirs = -1;	841	$ndirs = -1;
623	} else {	842	} else {
624	# if nlink == 2, we are finished	843	# if nlink == 2, we are finished
625	# on non-posix-fs's, we rely on nlink < 2	844	# for non-posix-fs's, we rely on nlink < 2
626	$ndirs = (stat _)[3] - 2	845	$ndirs = (stat _)[3] - 2
627	or return $grp->result ([], $entries);	846	or return $grp->result ([], $entries);
628	}	847	}
629		848
630	# sort into likely dirs and likely nondirs
631	# dirs == files without ".", short entries first
632	$entries = [map $_->[0],
633	sort { $b->[1] cmp $a->[1] }
634	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
635	@$entries];
636
637	my (@dirs, @nondirs);	849	my (@dirs, @nondirs);
638		850
639	my $statgrp = add $grp aio_group sub {	851	my $statgrp = add $grp aio_group sub {
640	$grp->result (\@dirs, \@nondirs);	852	$grp->result (\@dirs, \@nondirs);
641	};	853	};
642		854
643	limit $statgrp $maxreq;	855	limit $statgrp $maxreq;
644	feed $statgrp sub {	856	feed $statgrp sub {
645	return unless @$entries;	857	return unless @$entries;
646	my $entry = pop @$entries;	858	my $entry = shift @$entries;
647		859
648	aioreq_pri $pri;	860	aioreq_pri $pri;
649	add $statgrp aio_stat "$path/$entry/.", sub {	861	add $statgrp aio_stat "$path/$entry/.", sub {
650	if ($_[0] < 0) {	862	if ($_[0] < 0) {
651	push @nondirs, $entry;	863	push @nondirs, $entry;
…		…
672	};	884	};
673		885
674	$grp	886	$grp
675	}	887	}
676		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.
		927
677	=item aio_fsync $fh, $callback->($status)	928	=item aio_fsync $fh, $callback->($status)
678		929
679	Asynchronously call fsync on the given filehandle and call the callback	930	Asynchronously call fsync on the given filehandle and call the callback
680	with the fsync result code.	931	with the fsync result code.
681		932
…		…
684	Asynchronously call fdatasync on the given filehandle and call the	935	Asynchronously call fdatasync on the given filehandle and call the
685	callback with the fdatasync result code.	936	callback with the fdatasync result code.
686		937
687	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
688	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	Passes C<0> when everything went ok, and C<-1> on error.
		963
		964	=cut
		965
		966	sub aio_pathsync($;$) {
		967	my ($path, $cb) = @_;
		968
		969	my $pri = aioreq_pri;
		970	my $grp = aio_group $cb;
		971
		972	aioreq_pri $pri;
		973	add $grp aio_open $path, O_RDONLY, 0, sub {
		974	my ($fh) = @_;
		975	if ($fh) {
		976	aioreq_pri $pri;
		977	add $grp aio_fsync $fh, sub {
		978	$grp->result ($_[0]);
		979
		980	aioreq_pri $pri;
		981	add $grp aio_close $fh;
		982	};
		983	} else {
		984	$grp->result (-1);
		985	}
		986	};
		987
		988	$grp
		989	}
689		990
690	=item aio_group $callback->(...)	991	=item aio_group $callback->(...)
691		992
692	This is a very special aio request: Instead of doing something, it is a	993	This is a very special aio request: Instead of doing something, it is a
693	container for other aio requests, which is useful if you want to bundle	994	container for other aio requests, which is useful if you want to bundle
…		…
743	=item cancel $req	1044	=item cancel $req
744		1045
745	Cancels the request, if possible. Has the effect of skipping execution	1046	Cancels the request, if possible. Has the effect of skipping execution
746	when entering the B<execute> state and skipping calling the callback when	1047	when entering the B<execute> state and skipping calling the callback when
747	entering the the B<result> state, but will leave the request otherwise	1048	entering the the B<result> state, but will leave the request otherwise
748	untouched. That means that requests that currently execute will not be	1049	untouched (with the exception of readdir). That means that requests that
749	stopped and resources held by the request will not be freed prematurely.	1050	currently execute will not be stopped and resources held by the request
		1051	will not be freed prematurely.
750		1052
751	=item cb $req $callback->(...)	1053	=item cb $req $callback->(...)
752		1054
753	Replace (or simply set) the callback registered to the request.	1055	Replace (or simply set) the callback registered to the request.
754		1056
…		…
805	Their lifetime, simplified, looks like this: when they are empty, they	1107	Their lifetime, simplified, looks like this: when they are empty, they
806	will finish very quickly. If they contain only requests that are in the	1108	will finish very quickly. If they contain only requests that are in the
807	C<done> state, they will also finish. Otherwise they will continue to	1109	C<done> state, they will also finish. Otherwise they will continue to
808	exist.	1110	exist.
809		1111
810	That means after creating a group you have some time to add requests. And	1112	That means after creating a group you have some time to add requests
811	in the callbacks of those requests, you can add further requests to the	1113	(precisely before the callback has been invoked, which is only done within
812	group. And only when all those requests have finished will the the group	1114	the C<poll_cb>). And in the callbacks of those requests, you can add
813	itself finish.	1115	further requests to the group. And only when all those requests have
		1116	finished will the the group itself finish.
814		1117
815	=over 4	1118	=over 4
816		1119
817	=item add $grp ...	1120	=item add $grp ...
818		1121
…		…
830	itself. Useful when you queued a lot of events but got a result early.	1133	itself. Useful when you queued a lot of events but got a result early.
831		1134
832	=item $grp->result (...)	1135	=item $grp->result (...)
833		1136
834	Set the result value(s) that will be passed to the group callback when all	1137	Set the result value(s) that will be passed to the group callback when all
835	subrequests have finished and set thre groups errno to the current value	1138	subrequests have finished and set the groups errno to the current value
836	of errno (just like calling C<errno> without an error number). By default,	1139	of errno (just like calling C<errno> without an error number). By default,
837	no argument will be passed and errno is zero.	1140	no argument will be passed and errno is zero.
838		1141
839	=item $grp->errno ([$errno])	1142	=item $grp->errno ([$errno])
840		1143
…		…
851	=item feed $grp $callback->($grp)	1154	=item feed $grp $callback->($grp)
852		1155
853	Sets a feeder/generator on this group: every group can have an attached	1156	Sets a feeder/generator on this group: every group can have an attached
854	generator that generates requests if idle. The idea behind this is that,	1157	generator that generates requests if idle. The idea behind this is that,
855	although you could just queue as many requests as you want in a group,	1158	although you could just queue as many requests as you want in a group,
856	this might starve other requests for a potentially long time. For	1159	this might starve other requests for a potentially long time. For example,
857	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1160	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
858	requests, delaying any later requests for a long time.	1161	delaying any later requests for a long time.
859		1162
860	To avoid this, and allow incremental generation of requests, you can	1163	To avoid this, and allow incremental generation of requests, you can
861	instead a group and set a feeder on it that generates those requests. The	1164	instead a group and set a feeder on it that generates those requests. The
862	feed callback will be called whenever there are few enough (see C<limit>,	1165	feed callback will be called whenever there are few enough (see C<limit>,
863	below) requests active in the group itself and is expected to queue more	1166	below) requests active in the group itself and is expected to queue more
…		…
867	not impose any limits).	1170	not impose any limits).
868		1171
869	If the feed does not queue more requests when called, it will be	1172	If the feed does not queue more requests when called, it will be
870	automatically removed from the group.	1173	automatically removed from the group.
871		1174
872	If the feed limit is C<0>, it will be set to C<2> automatically.	1175	If the feed limit is C<0> when this method is called, it will be set to
		1176	C<2> automatically.
873		1177
874	Example:	1178	Example:
875		1179
876	# stat all files in @files, but only ever use four aio requests concurrently:	1180	# stat all files in @files, but only ever use four aio requests concurrently:
877		1181
…		…
889	Sets the feeder limit for the group: The feeder will be called whenever	1193	Sets the feeder limit for the group: The feeder will be called whenever
890	the group contains less than this many requests.	1194	the group contains less than this many requests.
891		1195
892	Setting the limit to C<0> will pause the feeding process.	1196	Setting the limit to C<0> will pause the feeding process.
893		1197
		1198	The default value for the limit is C<0>, but note that setting a feeder
		1199	automatically bumps it up to C<2>.
		1200
894	=back	1201	=back
895		1202
896	=head2 SUPPORT FUNCTIONS	1203	=head2 SUPPORT FUNCTIONS
897		1204
898	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	1205	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
…		…
900	=over 4	1207	=over 4
901		1208
902	=item $fileno = IO::AIO::poll_fileno	1209	=item $fileno = IO::AIO::poll_fileno
903		1210
904	Return the I<request result pipe file descriptor>. This filehandle must be	1211	Return the I<request result pipe file descriptor>. This filehandle must be
905	polled for reading by some mechanism outside this module (e.g. Event or	1212	polled for reading by some mechanism outside this module (e.g. EV, Glib,
906	select, see below or the SYNOPSIS). If the pipe becomes readable you have	1213	select and so on, see below or the SYNOPSIS). If the pipe becomes readable
907	to call C<poll_cb> to check the results.	1214	you have to call C<poll_cb> to check the results.
908		1215
909	See C<poll_cb> for an example.	1216	See C<poll_cb> for an example.
910		1217
911	=item IO::AIO::poll_cb	1218	=item IO::AIO::poll_cb
912		1219
913	Process some outstanding events on the result pipe. You have to call this	1220	Process some outstanding events on the result pipe. You have to call this
914	regularly. Returns the number of events processed. Returns immediately	1221	regularly. Returns C<0> if all events could be processed, or C<-1> if it
		1222	returned earlier for whatever reason. Returns immediately when no events
915	when no events are outstanding. The amount of events processed depends on	1223	are outstanding. The amount of events processed depends on the settings of
916	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.	1224	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
917		1225
918	If not all requests were processed for whatever reason, the filehandle	1226	If not all requests were processed for whatever reason, the filehandle
919	will still be ready when C<poll_cb> returns.	1227	will still be ready when C<poll_cb> returns, so normally you don't have to
		1228	do anything special to have it called later.
920		1229
921	Example: Install an Event watcher that automatically calls	1230	Example: Install an Event watcher that automatically calls
922	IO::AIO::poll_cb with high priority:	1231	IO::AIO::poll_cb with high priority (more examples can be found in the
		1232	SYNOPSIS section, at the top of this document):
923		1233
924	Event->io (fd => IO::AIO::poll_fileno,	1234	Event->io (fd => IO::AIO::poll_fileno,
925	poll => 'r', async => 1,	1235	poll => 'r', async => 1,
926	cb => \&IO::AIO::poll_cb);	1236	cb => \&IO::AIO::poll_cb);
927		1237
…		…
933	that are being processed by C<IO::AIO::poll_cb> in one call, respectively	1243	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
934	the maximum amount of time (default C<0>, meaning infinity) spent in	1244	the maximum amount of time (default C<0>, meaning infinity) spent in
935	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount	1245	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
936	of time C<poll_cb> is allowed to use).	1246	of time C<poll_cb> is allowed to use).
937		1247
		1248	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1249	syscall per request processed, which is not normally a problem unless your
		1250	callbacks are really really fast or your OS is really really slow (I am
		1251	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1252
938	Setting these is useful if you want to ensure some level of	1253	Setting these is useful if you want to ensure some level of
939	interactiveness when perl is not fast enough to process all requests in	1254	interactiveness when perl is not fast enough to process all requests in
940	time.	1255	time.
941		1256
942	For interactive programs, values such as C<0.01> to C<0.1> should be fine.	1257	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
943		1258
944	Example: Install an Event watcher that automatically calls	1259	Example: Install an Event watcher that automatically calls
945	IO::AIO::poll_some with low priority, to ensure that other parts of the	1260	IO::AIO::poll_cb with low priority, to ensure that other parts of the
946	program get the CPU sometimes even under high AIO load.	1261	program get the CPU sometimes even under high AIO load.
947		1262
948	# try not to spend much more than 0.1s in poll_cb	1263	# try not to spend much more than 0.1s in poll_cb
949	IO::AIO::max_poll_time 0.1;	1264	IO::AIO::max_poll_time 0.1;
950		1265
…		…
953	poll => 'r', nice => 1,	1268	poll => 'r', nice => 1,
954	cb => &IO::AIO::poll_cb);	1269	cb => &IO::AIO::poll_cb);
955		1270
956	=item IO::AIO::poll_wait	1271	=item IO::AIO::poll_wait
957		1272
		1273	If there are any outstanding requests and none of them in the result
958	Wait till the result filehandle becomes ready for reading (simply does a	1274	phase, wait till the result filehandle becomes ready for reading (simply
959	C<select> on the filehandle. This is useful if you want to synchronously	1275	does a C<select> on the filehandle. This is useful if you want to
960	wait for some requests to finish).	1276	synchronously wait for some requests to finish).
961		1277
962	See C<nreqs> for an example.	1278	See C<nreqs> for an example.
963		1279
964	=item IO::AIO::poll	1280	=item IO::AIO::poll
965		1281
966	Waits until some requests have been handled.	1282	Waits until some requests have been handled.
967		1283
		1284	Returns the number of requests processed, but is otherwise strictly
968	Strictly equivalent to:	1285	equivalent to:
969		1286
970	IO::AIO::poll_wait, IO::AIO::poll_cb	1287	IO::AIO::poll_wait, IO::AIO::poll_cb
971	if IO::AIO::nreqs;
972		1288
973	=item IO::AIO::flush	1289	=item IO::AIO::flush
974		1290
975	Wait till all outstanding AIO requests have been handled.	1291	Wait till all outstanding AIO requests have been handled.
976		1292
977	Strictly equivalent to:	1293	Strictly equivalent to:
978		1294
979	IO::AIO::poll_wait, IO::AIO::poll_cb	1295	IO::AIO::poll_wait, IO::AIO::poll_cb
980	while IO::AIO::nreqs;	1296	while IO::AIO::nreqs;
981		1297
		1298	=back
		1299
982	=head3 CONTROLLING THE NUMBER OF THREADS	1300	=head3 CONTROLLING THE NUMBER OF THREADS
		1301
		1302	=over
983		1303
984	=item IO::AIO::min_parallel $nthreads	1304	=item IO::AIO::min_parallel $nthreads
985		1305
986	Set the minimum number of AIO threads to C<$nthreads>. The current	1306	Set the minimum number of AIO threads to C<$nthreads>. The current
987	default is C<8>, which means eight asynchronous operations can execute	1307	default is C<8>, which means eight asynchronous operations can execute
…		…
1028		1348
1029	The default is probably ok in most situations, especially if thread	1349	The default is probably ok in most situations, especially if thread
1030	creation is fast. If thread creation is very slow on your system you might	1350	creation is fast. If thread creation is very slow on your system you might
1031	want to use larger values.	1351	want to use larger values.
1032		1352
1033	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1353	=item IO::AIO::max_outstanding $maxreqs
1034		1354
1035	This is a very bad function to use in interactive programs because it	1355	This is a very bad function to use in interactive programs because it
1036	blocks, and a bad way to reduce concurrency because it is inexact: Better	1356	blocks, and a bad way to reduce concurrency because it is inexact: Better
1037	use an C<aio_group> together with a feed callback.	1357	use an C<aio_group> together with a feed callback.
1038		1358
1039	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1359	Sets the maximum number of outstanding requests to C<$nreqs>. If you
1040	to queue up more than this number of requests, the next call to the	1360	do queue up more than this number of requests, the next call to the
1041	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1361	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1042	function will block until the limit is no longer exceeded.	1362	function will block until the limit is no longer exceeded.
1043		1363
1044	The default value is very large, so there is no practical limit on the	1364	The default value is very large, so there is no practical limit on the
1045	number of outstanding requests.	1365	number of outstanding requests.
1046		1366
1047	You can still queue as many requests as you want. Therefore,	1367	You can still queue as many requests as you want. Therefore,
1048	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1368	C<max_outstanding> is mainly useful in simple scripts (with low values) or
1049	as a stop gap to shield against fatal memory overflow (with large values).	1369	as a stop gap to shield against fatal memory overflow (with large values).
1050		1370
		1371	=back
		1372
1051	=head3 STATISTICAL INFORMATION	1373	=head3 STATISTICAL INFORMATION
		1374
		1375	=over
1052		1376
1053	=item IO::AIO::nreqs	1377	=item IO::AIO::nreqs
1054		1378
1055	Returns the number of requests currently in the ready, execute or pending	1379	Returns the number of requests currently in the ready, execute or pending
1056	states (i.e. for which their callback has not been invoked yet).	1380	states (i.e. for which their callback has not been invoked yet).
…		…
1070	Returns the number of requests currently in the pending state (executed,	1394	Returns the number of requests currently in the pending state (executed,
1071	but not yet processed by poll_cb).	1395	but not yet processed by poll_cb).
1072		1396
1073	=back	1397	=back
1074		1398
		1399	=head3 MISCELLANEOUS FUNCTIONS
		1400
		1401	IO::AIO implements some functions that might be useful, but are not
		1402	asynchronous.
		1403
		1404	=over 4
		1405
		1406	=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
		1407
		1408	Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
		1409	but is blocking (this makes most sense if you know the input data is
		1410	likely cached already and the output filehandle is set to non-blocking
		1411	operations).
		1412
		1413	Returns the number of bytes copied, or C<-1> on error.
		1414
		1415	=item IO::AIO::fadvise $fh, $offset, $len, $advice
		1416
		1417	Simply calls the C<posix_fadvise> function (see it's
		1418	manpage for details). The following advice constants are
		1419	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
		1420	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
		1421	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
		1422
		1423	On systems that do not implement C<posix_fadvise>, this function returns
		1424	ENOSYS, otherwise the return value of C<posix_fadvise>.
		1425
		1426	=back
		1427
1075	=cut	1428	=cut
1076		1429
1077	# support function to convert a fd into a perl filehandle
1078	sub _fd2fh {
1079	return undef if $_[0] < 0;
1080
1081	# try to generate nice filehandles
1082	my $sym = "IO::AIO::fd#$_[0]";
1083	local *$sym;
1084
1085	open *$sym, "+<&=$_[0]" # usually works under any unix
1086	or open *$sym, "<&=$_[0]" # cygwin needs this
1087	or open *$sym, ">&=$_[0]" # or this
1088	or return undef;
1089
1090	*$sym
1091	}
1092
1093	min_parallel 8;	1430	min_parallel 8;
1094		1431
1095	END {	1432	END { flush }
1096	min_parallel 1;
1097	flush;
1098	};
1099		1433
1100	1;	1434	1;
1101		1435
1102	=head2 FORK BEHAVIOUR	1436	=head2 FORK BEHAVIOUR
1103		1437
…		…
1123	bytes of memory. In addition, stat requests need a stat buffer (possibly	1457	bytes of memory. In addition, stat requests need a stat buffer (possibly
1124	a few hundred bytes), readdir requires a result buffer and so on. Perl	1458	a few hundred bytes), readdir requires a result buffer and so on. Perl
1125	scalars and other data passed into aio requests will also be locked and	1459	scalars and other data passed into aio requests will also be locked and
1126	will consume memory till the request has entered the done state.	1460	will consume memory till the request has entered the done state.
1127		1461
1128	This is now awfully much, so queuing lots of requests is not usually a	1462	This is not awfully much, so queuing lots of requests is not usually a
1129	problem.	1463	problem.
1130		1464
1131	Per-thread usage:	1465	Per-thread usage:
1132		1466
1133	In the execution phase, some aio requests require more memory for	1467	In the execution phase, some aio requests require more memory for
…		…
1138		1472
1139	Known bugs will be fixed in the next release.	1473	Known bugs will be fixed in the next release.
1140		1474
1141	=head1 SEE ALSO	1475	=head1 SEE ALSO
1142		1476
1143	L<Coro::AIO>.	1477	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1478	more natural syntax.
1144		1479
1145	=head1 AUTHOR	1480	=head1 AUTHOR
1146		1481
1147	Marc Lehmann <schmorp@schmorp.de>	1482	Marc Lehmann <schmorp@schmorp.de>
1148	http://home.schmorp.de/	1483	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs. Revision 1.161 by root, Tue Jul 14 00:32:27 2009 UTC

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Revision 1.86 by root, Sat Oct 28 23:32:29 2006 UTC vs.
Revision 1.161 by root, Tue Jul 14 00:32:27 2009 UTC