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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs.
Revision 1.154 by root, Sat Jun 13 14:58:33 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 $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);
…		…
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.
		58
		59	Asynchronous means that operations that can normally block your program
		60	(e.g. reading from disk) will be done asynchronously: the operation
		61	will still block, but you can do something else in the meantime. This
		62	is extremely useful for programs that need to stay interactive even
		63	when doing heavy I/O (GUI programs, high performance network servers
		64	etc.), but can also be used to easily do operations in parallel that are
		65	normally done sequentially, e.g. stat'ing many files, which is much faster
		66	on a RAID volume or over NFS when you do a number of stat operations
		67	concurrently.
		68
		69	While most of this works on all types of file descriptors (for
		70	example sockets), using these functions on file descriptors that
		71	support nonblocking operation (again, sockets, pipes etc.) is very
		72	inefficient. Use an event loop for that (such as the L<Event\|Event>
		73	module): IO::AIO will naturally fit into such an event loop itself.
55		74
56	In this version, a number of threads are started that execute your	75	In this version, a number of threads are started that execute your
57	requests and signal their completion. You don't need thread support	76	requests and signal their completion. You don't need thread support
58	in perl, and the threads created by this module will not be visible	77	in perl, and the threads created by this module will not be visible
59	to perl. In the future, this module might make use of the native aio	78	to perl. In the future, this module might make use of the native aio
60	functions available on many operating systems. However, they are often	79	functions available on many operating systems. However, they are often
61	not well-supported or restricted (Linux doesn't allow them on normal	80	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	files currently, for example), and they would only support aio_read and	81	files currently, for example), and they would only support aio_read and
63	aio_write, so the remaining functionality would have to be implemented	82	aio_write, so the remaining functionality would have to be implemented
64	using threads anyway.	83	using threads anyway.
65		84
66	Although the module will work with in the presence of other (Perl-)	85	Although the module will work in the presence of other (Perl-) threads,
67	threads, it is currently not reentrant in any way, so use appropriate	86	it is currently not reentrant in any way, so use appropriate locking
68	locking yourself, always call C<poll_cb> from within the same thread, or	87	yourself, always call C<poll_cb> from within the same thread, or never
69	never call C<poll_cb> (or other C<aio_> functions) recursively.	88	call C<poll_cb> (or other C<aio_> functions) recursively.
		89
		90	=head2 EXAMPLE
		91
		92	This is a simple example that uses the Event module and loads
		93	F</etc/passwd> asynchronously:
		94
		95	use Fcntl;
		96	use Event;
		97	use IO::AIO;
		98
		99	# register the IO::AIO callback with Event
		100	Event->io (fd => IO::AIO::poll_fileno,
		101	poll => 'r',
		102	cb => \&IO::AIO::poll_cb);
		103
		104	# queue the request to open /etc/passwd
		105	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		106	my $fh = shift
		107	or die "error while opening: $!";
		108
		109	# stat'ing filehandles is generally non-blocking
		110	my $size = -s $fh;
		111
		112	# queue a request to read the file
		113	my $contents;
		114	aio_read $fh, 0, $size, $contents, 0, sub {
		115	$_[0] == $size
		116	or die "short read: $!";
		117
		118	close $fh;
		119
		120	# file contents now in $contents
		121	print $contents;
		122
		123	# exit event loop and program
		124	Event::unloop;
		125	};
		126	};
		127
		128	# possibly queue up other requests, or open GUI windows,
		129	# check for sockets etc. etc.
		130
		131	# process events as long as there are some:
		132	Event::loop;
70		133
71	=head1 REQUEST ANATOMY AND LIFETIME	134	=head1 REQUEST ANATOMY AND LIFETIME
72		135
73	Every C<aio_*> function creates a request. which is a C data structure not	136	Every C<aio_*> function creates a request. which is a C data structure not
74	directly visible to Perl.	137	directly visible to Perl.
…		…
116	Request has reached the end of its lifetime and holds no resources anymore	179	Request has reached the end of its lifetime and holds no resources anymore
117	(except possibly for the Perl object, but its connection to the actual	180	(except possibly for the Perl object, but its connection to the actual
118	aio request is severed and calling its methods will either do nothing or	181	aio request is severed and calling its methods will either do nothing or
119	result in a runtime error).	182	result in a runtime error).
120		183
		184	=back
		185
121	=cut	186	=cut
122		187
123	package IO::AIO;	188	package IO::AIO;
		189
		190	use Carp ();
124		191
125	no warnings;	192	no warnings;
126	use strict 'vars';	193	use strict 'vars';
127		194
128	use base 'Exporter';	195	use base 'Exporter';
129		196
130	BEGIN {	197	BEGIN {
131	our $VERSION = '2.0';	198	our $VERSION = '3.23';
132		199
133	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	200	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
134	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	201	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	202	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
136	aio_copy aio_group aio_nop aio_mknod);	203	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
		204	aio_rename aio_link aio_move aio_copy aio_group
		205	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
		206	aio_chmod aio_utime aio_truncate);
		207
137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	208	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	209	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139	min_parallel max_parallel nreqs nready npending);	210	min_parallel max_parallel max_idle
		211	nreqs nready npending nthreads
		212	max_poll_time max_poll_reqs);
		213
		214	push @AIO_REQ, qw(aio_busy); # not exported
140		215
141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	216	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142		217
143	require XSLoader;	218	require XSLoader;
144	XSLoader::load ("IO::AIO", $VERSION);	219	XSLoader::load ("IO::AIO", $VERSION);
145	}	220	}
146		221
147	=head1 FUNCTIONS	222	=head1 FUNCTIONS
148		223
149	=head2 AIO FUNCTIONS	224	=head2 AIO REQUEST FUNCTIONS
150		225
151	All the C<aio_*> calls are more or less thin wrappers around the syscall	226	All the C<aio_*> calls are more or less thin wrappers around the syscall
152	with the same name (sans C<aio_>). The arguments are similar or identical,	227	with the same name (sans C<aio_>). The arguments are similar or identical,
153	and they all accept an additional (and optional) C<$callback> argument	228	and they all accept an additional (and optional) C<$callback> argument
154	which must be a code reference. This code reference will get called with	229	which must be a code reference. This code reference will get called with
155	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	230	the syscall return code (e.g. most syscalls return C<-1> on error, unlike
156	perl, which usually delivers "false") as it's sole argument when the given	231	perl, which usually delivers "false") as its sole argument after the given
157	syscall has been executed asynchronously.	232	syscall has been executed asynchronously.
158		233
159	All functions expecting a filehandle keep a copy of the filehandle	234	All functions expecting a filehandle keep a copy of the filehandle
160	internally until the request has finished.	235	internally until the request has finished.
161		236
162	All requests return objects of type L<IO::AIO::REQ> that allow further	237	All functions return request objects of type L<IO::AIO::REQ> that allow
163	manipulation of those requests while they are in-flight.	238	further manipulation of those requests while they are in-flight.
164		239
165	The pathnames you pass to these routines I<must> be absolute and	240	The pathnames you pass to these routines I<must> be absolute and
166	encoded in byte form. The reason for the former is that at the time the	241	encoded as octets. The reason for the former is that at the time the
167	request is being executed, the current working directory could have	242	request is being executed, the current working directory could have
168	changed. Alternatively, you can make sure that you never change the	243	changed. Alternatively, you can make sure that you never change the
169	current working directory.	244	current working directory anywhere in the program and then use relative
		245	paths.
170		246
171	To encode pathnames to byte form, either make sure you either: a)	247	To encode pathnames as octets, either make sure you either: a) always pass
172	always pass in filenames you got from outside (command line, readdir	248	in filenames you got from outside (command line, readdir etc.) without
173	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	249	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174	your pathnames to the locale (or other) encoding in effect in the user	250	your pathnames to the locale (or other) encoding in effect in the user
175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	251	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176	use something else.	252	use something else to ensure your scalar has the correct contents.
		253
		254	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		255	handles correctly whether it is set or not.
177		256
178	=over 4	257	=over 4
179		258
180	=item $prev_pri = aioreq_pri [$pri]	259	=item $prev_pri = aioreq_pri [$pri]
181		260
…		…
201	aio_read $_[0], ..., sub {	280	aio_read $_[0], ..., sub {
202	...	281	...
203	};	282	};
204	};	283	};
205		284
		285
206	=item aioreq_nice $pri_adjust	286	=item aioreq_nice $pri_adjust
207		287
208	Similar to C<aioreq_pri>, but subtracts the given value from the current	288	Similar to C<aioreq_pri>, but subtracts the given value from the current
209	priority, so effects are cumulative.	289	priority, so the effect is cumulative.
		290
210		291
211	=item aio_open $pathname, $flags, $mode, $callback->($fh)	292	=item aio_open $pathname, $flags, $mode, $callback->($fh)
212		293
213	Asynchronously open or create a file and call the callback with a newly	294	Asynchronously open or create a file and call the callback with a newly
214	created filehandle for the file.	295	created filehandle for the file.
…		…
220	list. They are the same as used by C<sysopen>.	301	list. They are the same as used by C<sysopen>.
221		302
222	Likewise, C<$mode> specifies the mode of the newly created file, if it	303	Likewise, C<$mode> specifies the mode of the newly created file, if it
223	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	304	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
224	except that it is mandatory (i.e. use C<0> if you don't create new files,	305	except that it is mandatory (i.e. use C<0> if you don't create new files,
225	and C<0666> or C<0777> if you do).	306	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		307	by the umask in effect then the request is being executed, so better never
		308	change the umask.
226		309
227	Example:	310	Example:
228		311
229	aio_open "/etc/passwd", O_RDONLY, 0, sub {	312	aio_open "/etc/passwd", O_RDONLY, 0, sub {
230	if ($_[0]) {	313	if ($_[0]) {
…		…
233	} else {	316	} else {
234	die "open failed: $!\n";	317	die "open failed: $!\n";
235	}	318	}
236	};	319	};
237		320
		321
238	=item aio_close $fh, $callback->($status)	322	=item aio_close $fh, $callback->($status)
239		323
240	Asynchronously close a file and call the callback with the result	324	Asynchronously close a file and call the callback with the result
241	code. I<WARNING:> although accepted, you should not pass in a perl	325	code.
242	filehandle here, as perl will likely close the file descriptor another
243	time when the filehandle is destroyed. Normally, you can safely call perls
244	C<close> or just let filehandles go out of scope.
245		326
246	This is supposed to be a bug in the API, so that might change. It's	327	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247	therefore best to avoid this function.	328	closing the file descriptor associated with the filehandle itself.
		329
		330	Therefore, C<aio_close> will not close the filehandle - instead it will
		331	use dup2 to overwrite the file descriptor with the write-end of a pipe
		332	(the pipe fd will be created on demand and will be cached).
		333
		334	Or in other words: the file descriptor will be closed, but it will not be
		335	free for reuse until the perl filehandle is closed.
		336
		337	=cut
248		338
249	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	339	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250		340
251	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	341	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252		342
253	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	343	Reads or writes C<$length> bytes from or to the specified C<$fh> and
254	into the scalar given by C<data> and offset C<dataoffset> and calls the	344	C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
255	callback without the actual number of bytes read (or -1 on error, just	345	and calls the callback without the actual number of bytes read (or -1 on
256	like the syscall).	346	error, just like the syscall).
		347
		348	C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
		349	offset plus the actual number of bytes read.
		350
		351	If C<$offset> is undefined, then the current file descriptor offset will
		352	be used (and updated), otherwise the file descriptor offset will not be
		353	changed by these calls.
		354
		355	If C<$length> is undefined in C<aio_write>, use the remaining length of
		356	C<$data>.
		357
		358	If C<$dataoffset> is less than zero, it will be counted from the end of
		359	C<$data>.
257		360
258	The C<$data> scalar I<MUST NOT> be modified in any way while the request	361	The C<$data> scalar I<MUST NOT> be modified in any way while the request
259	is outstanding. Modifying it can result in segfaults or WW3 (if the	362	is outstanding. Modifying it can result in segfaults or World War III (if
260	necessary/optional hardware is installed).	363	the necessary/optional hardware is installed).
261		364
262	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	365	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263	offset C<0> within the scalar:	366	offset C<0> within the scalar:
264		367
265	aio_read $fh, 7, 15, $buffer, 0, sub {	368	aio_read $fh, 7, 15, $buffer, 0, sub {
266	$_[0] > 0 or die "read error: $!";	369	$_[0] > 0 or die "read error: $!";
267	print "read $_[0] bytes: <$buffer>\n";	370	print "read $_[0] bytes: <$buffer>\n";
268	};	371	};
		372
269		373
270	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	374	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
271		375
272	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	376	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
273	reading at byte offset C<$in_offset>, and starts writing at the current	377	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
287	C<$in_fh> than are written, and there is no way to find out how many	391	C<$in_fh> than are written, and there is no way to find out how many
288	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	392	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
289	provides the number of bytes written to C<$out_fh>. Only if the result	393	provides the number of bytes written to C<$out_fh>. Only if the result
290	value equals C<$length> one can assume that C<$length> bytes have been	394	value equals C<$length> one can assume that C<$length> bytes have been
291	read.	395	read.
		396
292		397
293	=item aio_readahead $fh,$offset,$length, $callback->($retval)	398	=item aio_readahead $fh,$offset,$length, $callback->($retval)
294		399
295	C<aio_readahead> populates the page cache with data from a file so that	400	C<aio_readahead> populates the page cache with data from a file so that
296	subsequent reads from that file will not block on disk I/O. The C<$offset>	401	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
302	file. The current file offset of the file is left unchanged.	407	file. The current file offset of the file is left unchanged.
303		408
304	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	409	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
305	emulated by simply reading the data, which would have a similar effect.	410	emulated by simply reading the data, which would have a similar effect.
306		411
		412
307	=item aio_stat $fh_or_path, $callback->($status)	413	=item aio_stat $fh_or_path, $callback->($status)
308		414
309	=item aio_lstat $fh, $callback->($status)	415	=item aio_lstat $fh, $callback->($status)
310		416
311	Works like perl's C<stat> or C<lstat> in void context. The callback will	417	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
324	aio_stat "/etc/passwd", sub {	430	aio_stat "/etc/passwd", sub {
325	$_[0] and die "stat failed: $!";	431	$_[0] and die "stat failed: $!";
326	print "size is ", -s _, "\n";	432	print "size is ", -s _, "\n";
327	};	433	};
328		434
		435
		436	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		437
		438	Works like perl's C<utime> function (including the special case of $atime
		439	and $mtime being undef). Fractional times are supported if the underlying
		440	syscalls support them.
		441
		442	When called with a pathname, uses utimes(2) if available, otherwise
		443	utime(2). If called on a file descriptor, uses futimes(2) if available,
		444	otherwise returns ENOSYS, so this is not portable.
		445
		446	Examples:
		447
		448	# set atime and mtime to current time (basically touch(1)):
		449	aio_utime "path", undef, undef;
		450	# set atime to current time and mtime to beginning of the epoch:
		451	aio_utime "path", time, undef; # undef==0
		452
		453
		454	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		455
		456	Works like perl's C<chown> function, except that C<undef> for either $uid
		457	or $gid is being interpreted as "do not change" (but -1 can also be used).
		458
		459	Examples:
		460
		461	# same as "chown root path" in the shell:
		462	aio_chown "path", 0, -1;
		463	# same as above:
		464	aio_chown "path", 0, undef;
		465
		466
		467	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		468
		469	Works like truncate(2) or ftruncate(2).
		470
		471
		472	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		473
		474	Works like perl's C<chmod> function.
		475
		476
329	=item aio_unlink $pathname, $callback->($status)	477	=item aio_unlink $pathname, $callback->($status)
330		478
331	Asynchronously unlink (delete) a file and call the callback with the	479	Asynchronously unlink (delete) a file and call the callback with the
332	result code.	480	result code.
333		481
		482
334	=item aio_mknod $path, $mode, $dev, $callback->($status)	483	=item aio_mknod $path, $mode, $dev, $callback->($status)
335		484
		485	[EXPERIMENTAL]
		486
336	Asynchronously create a device node (or fifo). See mknod(2): the only	487	Asynchronously create a device node (or fifo). See mknod(2).
337	portable value for C<$mode> is C<S_IFIFO> ored with permissions, and C<0>	488
338	for C<$dev>.	489	The only (POSIX-) portable way of calling this function is:
		490
		491	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		492
339		493
340	=item aio_link $srcpath, $dstpath, $callback->($status)	494	=item aio_link $srcpath, $dstpath, $callback->($status)
341		495
342	Asynchronously create a new link to the existing object at C<$srcpath> at	496	Asynchronously create a new link to the existing object at C<$srcpath> at
343	the path C<$dstpath> and call the callback with the result code.	497	the path C<$dstpath> and call the callback with the result code.
344		498
		499
345	=item aio_symlink $srcpath, $dstpath, $callback->($status)	500	=item aio_symlink $srcpath, $dstpath, $callback->($status)
346		501
347	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	502	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
348	the path C<$dstpath> and call the callback with the result code.	503	the path C<$dstpath> and call the callback with the result code.
349		504
		505
		506	=item aio_readlink $path, $callback->($link)
		507
		508	Asynchronously read the symlink specified by C<$path> and pass it to
		509	the callback. If an error occurs, nothing or undef gets passed to the
		510	callback.
		511
		512
350	=item aio_rename $srcpath, $dstpath, $callback->($status)	513	=item aio_rename $srcpath, $dstpath, $callback->($status)
351		514
352	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	515	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
353	rename(2) and call the callback with the result code.	516	rename(2) and call the callback with the result code.
354		517
		518
		519	=item aio_mkdir $pathname, $mode, $callback->($status)
		520
		521	Asynchronously mkdir (create) a directory and call the callback with
		522	the result code. C<$mode> will be modified by the umask at the time the
		523	request is executed, so do not change your umask.
		524
		525
355	=item aio_rmdir $pathname, $callback->($status)	526	=item aio_rmdir $pathname, $callback->($status)
356		527
357	Asynchronously rmdir (delete) a directory and call the callback with the	528	Asynchronously rmdir (delete) a directory and call the callback with the
358	result code.	529	result code.
		530
359		531
360	=item aio_readdir $pathname, $callback->($entries)	532	=item aio_readdir $pathname, $callback->($entries)
361		533
362	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	534	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
363	directory (i.e. opendir + readdir + closedir). The entries will not be	535	directory (i.e. opendir + readdir + closedir). The entries will not be
364	sorted, and will B<NOT> include the C<.> and C<..> entries.	536	sorted, and will B<NOT> include the C<.> and C<..> entries.
365		537
366	The callback a single argument which is either C<undef> or an array-ref	538	The callback is passed a single argument which is either C<undef> or an
367	with the filenames.	539	array-ref with the filenames.
		540
		541
		542	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
		543
		544	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
		545	behaviour and output format. In case of an error, C<$entries> will be
		546	C<undef>.
		547
		548	The flags are a combination of the following constants, ORed together (the
		549	flags will also be passed to the callback, possibly modified):
		550
		551	=over 4
		552
		553	=item IO::AIO::READDIR_DENTS
		554
		555	When this flag is off, then the callback gets an arrayref with of names
		556	only (as with C<aio_readdir>), otherwise it gets an arrayref with
		557	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
		558	entry in more detail.
		559
		560	C<$name> is the name of the entry.
		561
		562	C<$type> is one of the C<IO::AIO::DT_xxx> constants:
		563
		564	C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
		565	C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
		566	C<IO::AIO::DT_WHT>.
		567
		568	C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
		569	know, you have to run stat yourself. Also, for speed reasons, the C<$type>
		570	scalars are read-only: you can not modify them.
		571
		572	C<$inode> is the inode number (which might not be exact on systems with 64
		573	bit inode numbers and 32 bit perls). On systems that do not deliver the
		574	inode information, this will always be zero.
		575
		576	=item IO::AIO::READDIR_DIRS_FIRST
		577
		578	When this flag is set, then the names will be returned in an order where
		579	likely directories come first. This is useful when you need to quickly
		580	find directories, or you want to find all directories while avoiding to
		581	stat() each entry.
		582
		583	If the system returns type information in readdir, then this is used
		584	to find directories directly. Otherwise, likely directories are files
		585	beginning with ".", or otherwise files with no dots, of which files with
		586	short names are tried first.
		587
		588	=item IO::AIO::READDIR_STAT_ORDER
		589
		590	When this flag is set, then the names will be returned in an order
		591	suitable for stat()'ing each one. That is, when you plan to stat()
		592	all files in the given directory, then the returned order will likely
		593	be fastest.
		594
		595	If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
		596	the likely dirs come first, resulting in a less optimal stat order.
		597
		598	=item IO::AIO::READDIR_FOUND_UNKNOWN
		599
		600	This flag should not be set when calling C<aio_readdirx>. Instead, it
		601	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
		602	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
		603	C<$type>'s are known, which can be used to speed up some algorithms.
		604
		605	=back
		606
		607
		608	=item aio_load $path, $data, $callback->($status)
		609
		610	This is a composite request that tries to fully load the given file into
		611	memory. Status is the same as with aio_read.
		612
		613	=cut
		614
		615	sub aio_load($$;$) {
		616	my ($path, undef, $cb) = @_;
		617	my $data = \$_[1];
		618
		619	my $pri = aioreq_pri;
		620	my $grp = aio_group $cb;
		621
		622	aioreq_pri $pri;
		623	add $grp aio_open $path, O_RDONLY, 0, sub {
		624	my $fh = shift
		625	or return $grp->result (-1);
		626
		627	aioreq_pri $pri;
		628	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		629	$grp->result ($_[0]);
		630	};
		631	};
		632
		633	$grp
		634	}
368		635
369	=item aio_copy $srcpath, $dstpath, $callback->($status)	636	=item aio_copy $srcpath, $dstpath, $callback->($status)
370		637
371	Try to copy the I<file> (directories not supported as either source or	638	Try to copy the I<file> (directories not supported as either source or
372	destination) from C<$srcpath> to C<$dstpath> and call the callback with	639	destination) from C<$srcpath> to C<$dstpath> and call the callback with
373	the C<0> (error) or C<-1> ok.	640	the C<0> (error) or C<-1> ok.
374		641
375	This is a composite request that it creates the destination file with	642	This is a composite request that creates the destination file with
376	mode 0200 and copies the contents of the source file into it using	643	mode 0200 and copies the contents of the source file into it using
377	C<aio_sendfile>, followed by restoring atime, mtime, access mode and	644	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
378	uid/gid, in that order.	645	uid/gid, in that order.
379		646
380	If an error occurs, the partial destination file will be unlinked, if	647	If an error occurs, the partial destination file will be unlinked, if
…		…
390	my $grp = aio_group $cb;	657	my $grp = aio_group $cb;
391		658
392	aioreq_pri $pri;	659	aioreq_pri $pri;
393	add $grp aio_open $src, O_RDONLY, 0, sub {	660	add $grp aio_open $src, O_RDONLY, 0, sub {
394	if (my $src_fh = $_[0]) {	661	if (my $src_fh = $_[0]) {
395	my @stat = stat $src_fh;	662	my @stat = stat $src_fh; # hmm, might bock over nfs?
396		663
397	aioreq_pri $pri;	664	aioreq_pri $pri;
398	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	665	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
399	if (my $dst_fh = $_[0]) {	666	if (my $dst_fh = $_[0]) {
400	aioreq_pri $pri;	667	aioreq_pri $pri;
401	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	668	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
402	if ($_[0] == $stat[7]) {	669	if ($_[0] == $stat[7]) {
403	$grp->result (0);	670	$grp->result (0);
404	close $src_fh;	671	close $src_fh;
405		672
406	# those should not normally block. should. should.	673	my $ch = sub {
		674	aioreq_pri $pri;
		675	add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
		676	aioreq_pri $pri;
		677	add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
		678	aioreq_pri $pri;
		679	add $grp aio_close $dst_fh;
		680	}
		681	};
		682	};
		683
		684	aioreq_pri $pri;
		685	add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
		686	if ($_[0] < 0 && $! == ENOSYS) {
		687	aioreq_pri $pri;
407	utime $stat[8], $stat[9], $dst;	688	add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
408	chmod $stat[2] & 07777, $dst_fh;	689	} else {
409	chown $stat[4], $stat[5], $dst_fh;	690	$ch->();
		691	}
410	close $dst_fh;	692	};
411	} else {	693	} else {
412	$grp->result (-1);	694	$grp->result (-1);
413	close $src_fh;	695	close $src_fh;
414	close $dst_fh;	696	close $dst_fh;
415		697
…		…
434		716
435	Try to move the I<file> (directories not supported as either source or	717	Try to move the I<file> (directories not supported as either source or
436	destination) from C<$srcpath> to C<$dstpath> and call the callback with	718	destination) from C<$srcpath> to C<$dstpath> and call the callback with
437	the C<0> (error) or C<-1> ok.	719	the C<0> (error) or C<-1> ok.
438		720
439	This is a composite request that tries to rename(2) the file first. If	721	This is a composite request that tries to rename(2) the file first; if
440	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if	722	rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
441	that is successful, unlinking the C<$srcpath>.	723	that is successful, unlinks the C<$srcpath>.
442		724
443	=cut	725	=cut
444		726
445	sub aio_move($$;$) {	727	sub aio_move($$;$) {
446	my ($src, $dst, $cb) = @_;	728	my ($src, $dst, $cb) = @_;
…		…
493		775
494	Implementation notes.	776	Implementation notes.
495		777
496	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.	778	The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
497		779
		780	If readdir returns file type information, then this is used directly to
		781	find directories.
		782
498	After reading the directory, the modification time, size etc. of the	783	Otherwise, after reading the directory, the modification time, size etc.
499	directory before and after the readdir is checked, and if they match (and	784	of the directory before and after the readdir is checked, and if they
500	isn't the current time), the link count will be used to decide how many	785	match (and isn't the current time), the link count will be used to decide
501	entries are directories (if >= 2). Otherwise, no knowledge of the number	786	how many entries are directories (if >= 2). Otherwise, no knowledge of the
502	of subdirectories will be assumed.	787	number of subdirectories will be assumed.
503		788
504	Then entries will be sorted into likely directories (everything without	789	Then entries will be sorted into likely directories a non-initial dot
505	a non-initial dot currently) and likely non-directories (everything	790	currently) and likely non-directories (see C<aio_readdirx>). Then every
506	else). Then every entry plus an appended C</.> will be C<stat>'ed,	791	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
507	likely directories first. If that succeeds, it assumes that the entry	792	in order of their inode numbers. If that succeeds, it assumes that the
508	is a directory or a symlink to directory (which will be checked	793	entry is a directory or a symlink to directory (which will be checked
509	seperately). This is often faster than stat'ing the entry itself because	794	seperately). This is often faster than stat'ing the entry itself because
510	filesystems might detect the type of the entry without reading the inode	795	filesystems might detect the type of the entry without reading the inode
511	data (e.g. ext2fs filetype feature).	796	data (e.g. ext2fs filetype feature), even on systems that cannot return
		797	the filetype information on readdir.
512		798
513	If the known number of directories (link count - 2) has been reached, the	799	If the known number of directories (link count - 2) has been reached, the
514	rest of the entries is assumed to be non-directories.	800	rest of the entries is assumed to be non-directories.
515		801
516	This only works with certainty on POSIX (= UNIX) filesystems, which	802	This only works with certainty on POSIX (= UNIX) filesystems, which
…		…
520	as those tend to return 0 or 1 as link counts, which disables the	806	as those tend to return 0 or 1 as link counts, which disables the
521	directory counting heuristic.	807	directory counting heuristic.
522		808
523	=cut	809	=cut
524		810
525	sub aio_scandir($$$) {	811	sub aio_scandir($$;$) {
526	my ($path, $maxreq, $cb) = @_;	812	my ($path, $maxreq, $cb) = @_;
527		813
528	my $pri = aioreq_pri;	814	my $pri = aioreq_pri;
529		815
530	my $grp = aio_group $cb;	816	my $grp = aio_group $cb;
…		…
538	my $now = time;	824	my $now = time;
539	my $hash1 = join ":", (stat _)[0,1,3,7,9];	825	my $hash1 = join ":", (stat _)[0,1,3,7,9];
540		826
541	# read the directory entries	827	# read the directory entries
542	aioreq_pri $pri;	828	aioreq_pri $pri;
543	add $grp aio_readdir $path, sub {	829	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
544	my $entries = shift	830	my $entries = shift
545	or return $grp->result ();	831	or return $grp->result ();
546		832
547	# stat the dir another time	833	# stat the dir another time
548	aioreq_pri $pri;	834	aioreq_pri $pri;
…		…
554	# take the slow route if anything looks fishy	840	# take the slow route if anything looks fishy
555	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	841	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
556	$ndirs = -1;	842	$ndirs = -1;
557	} else {	843	} else {
558	# if nlink == 2, we are finished	844	# if nlink == 2, we are finished
559	# on non-posix-fs's, we rely on nlink < 2	845	# for non-posix-fs's, we rely on nlink < 2
560	$ndirs = (stat _)[3] - 2	846	$ndirs = (stat _)[3] - 2
561	or return $grp->result ([], $entries);	847	or return $grp->result ([], $entries);
562	}	848	}
563		849
564	# sort into likely dirs and likely nondirs
565	# dirs == files without ".", short entries first
566	$entries = [map $_->[0],
567	sort { $b->[1] cmp $a->[1] }
568	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
569	@$entries];
570
571	my (@dirs, @nondirs);	850	my (@dirs, @nondirs);
572		851
573	my $statgrp = add $grp aio_group sub {	852	my $statgrp = add $grp aio_group sub {
574	$grp->result (\@dirs, \@nondirs);	853	$grp->result (\@dirs, \@nondirs);
575	};	854	};
576		855
577	limit $statgrp $maxreq;	856	limit $statgrp $maxreq;
578	feed $statgrp sub {	857	feed $statgrp sub {
579	return unless @$entries;	858	return unless @$entries;
580	my $entry = pop @$entries;	859	my $entry = shift @$entries;
581		860
582	aioreq_pri $pri;	861	aioreq_pri $pri;
583	add $statgrp aio_stat "$path/$entry/.", sub {	862	add $statgrp aio_stat "$path/$entry/.", sub {
584	if ($_[0] < 0) {	863	if ($_[0] < 0) {
585	push @nondirs, $entry;	864	push @nondirs, $entry;
…		…
606	};	885	};
607		886
608	$grp	887	$grp
609	}	888	}
610		889
		890	=item aio_rmtree $path, $callback->($status)
		891
		892	Delete a directory tree starting (and including) C<$path>, return the
		893	status of the final C<rmdir> only. This is a composite request that
		894	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		895	everything else.
		896
		897	=cut
		898
		899	sub aio_rmtree;
		900	sub aio_rmtree($;$) {
		901	my ($path, $cb) = @_;
		902
		903	my $pri = aioreq_pri;
		904	my $grp = aio_group $cb;
		905
		906	aioreq_pri $pri;
		907	add $grp aio_scandir $path, 0, sub {
		908	my ($dirs, $nondirs) = @_;
		909
		910	my $dirgrp = aio_group sub {
		911	add $grp aio_rmdir $path, sub {
		912	$grp->result ($_[0]);
		913	};
		914	};
		915
		916	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		917	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		918
		919	add $grp $dirgrp;
		920	};
		921
		922	$grp
		923	}
		924
		925	=item aio_sync $callback->($status)
		926
		927	Asynchronously call sync and call the callback when finished.
		928
611	=item aio_fsync $fh, $callback->($status)	929	=item aio_fsync $fh, $callback->($status)
612		930
613	Asynchronously call fsync on the given filehandle and call the callback	931	Asynchronously call fsync on the given filehandle and call the callback
614	with the fsync result code.	932	with the fsync result code.
615		933
…		…
618	Asynchronously call fdatasync on the given filehandle and call the	936	Asynchronously call fdatasync on the given filehandle and call the
619	callback with the fdatasync result code.	937	callback with the fdatasync result code.
620		938
621	If this call isn't available because your OS lacks it or it couldn't be	939	If this call isn't available because your OS lacks it or it couldn't be
622	detected, it will be emulated by calling C<fsync> instead.	940	detected, it will be emulated by calling C<fsync> instead.
		941
		942	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
		943
		944	Sync the data portion of the file specified by C<$offset> and C<$length>
		945	to disk (but NOT the metadata), by calling the Linux-specific
		946	sync_file_range call. If sync_file_range is not available or it returns
		947	ENOSYS, then fdatasync or fsync is being substituted.
		948
		949	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
		950	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
		951	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
		952	manpage for details.
		953
		954	=item aio_pathsync $path, $callback->($status)
		955
		956	This request tries to open, fsync and close the given path. This is a
		957	composite request intended to sync directories after directory operations
		958	(E.g. rename). This might not work on all operating systems or have any
		959	specific effect, but usually it makes sure that directory changes get
		960	written to disc. It works for anything that can be opened for read-only,
		961	not just directories.
		962
		963	Passes C<0> when everything went ok, and C<-1> on error.
		964
		965	=cut
		966
		967	sub aio_pathsync($;$) {
		968	my ($path, $cb) = @_;
		969
		970	my $pri = aioreq_pri;
		971	my $grp = aio_group $cb;
		972
		973	aioreq_pri $pri;
		974	add $grp aio_open $path, O_RDONLY, 0, sub {
		975	my ($fh) = @_;
		976	if ($fh) {
		977	aioreq_pri $pri;
		978	add $grp aio_fsync $fh, sub {
		979	$grp->result ($_[0]);
		980
		981	aioreq_pri $pri;
		982	add $grp aio_close $fh;
		983	};
		984	} else {
		985	$grp->result (-1);
		986	}
		987	};
		988
		989	$grp
		990	}
623		991
624	=item aio_group $callback->(...)	992	=item aio_group $callback->(...)
625		993
626	This is a very special aio request: Instead of doing something, it is a	994	This is a very special aio request: Instead of doing something, it is a
627	container for other aio requests, which is useful if you want to bundle	995	container for other aio requests, which is useful if you want to bundle
…		…
677	=item cancel $req	1045	=item cancel $req
678		1046
679	Cancels the request, if possible. Has the effect of skipping execution	1047	Cancels the request, if possible. Has the effect of skipping execution
680	when entering the B<execute> state and skipping calling the callback when	1048	when entering the B<execute> state and skipping calling the callback when
681	entering the the B<result> state, but will leave the request otherwise	1049	entering the the B<result> state, but will leave the request otherwise
682	untouched. That means that requests that currently execute will not be	1050	untouched (with the exception of readdir). That means that requests that
683	stopped and resources held by the request will not be freed prematurely.	1051	currently execute will not be stopped and resources held by the request
		1052	will not be freed prematurely.
684		1053
685	=item cb $req $callback->(...)	1054	=item cb $req $callback->(...)
686		1055
687	Replace (or simply set) the callback registered to the request.	1056	Replace (or simply set) the callback registered to the request.
688		1057
…		…
739	Their lifetime, simplified, looks like this: when they are empty, they	1108	Their lifetime, simplified, looks like this: when they are empty, they
740	will finish very quickly. If they contain only requests that are in the	1109	will finish very quickly. If they contain only requests that are in the
741	C<done> state, they will also finish. Otherwise they will continue to	1110	C<done> state, they will also finish. Otherwise they will continue to
742	exist.	1111	exist.
743		1112
744	That means after creating a group you have some time to add requests. And	1113	That means after creating a group you have some time to add requests
745	in the callbacks of those requests, you can add further requests to the	1114	(precisely before the callback has been invoked, which is only done within
746	group. And only when all those requests have finished will the the group	1115	the C<poll_cb>). And in the callbacks of those requests, you can add
747	itself finish.	1116	further requests to the group. And only when all those requests have
		1117	finished will the the group itself finish.
748		1118
749	=over 4	1119	=over 4
750		1120
751	=item add $grp ...	1121	=item add $grp ...
752		1122
…		…
764	itself. Useful when you queued a lot of events but got a result early.	1134	itself. Useful when you queued a lot of events but got a result early.
765		1135
766	=item $grp->result (...)	1136	=item $grp->result (...)
767		1137
768	Set the result value(s) that will be passed to the group callback when all	1138	Set the result value(s) that will be passed to the group callback when all
769	subrequests have finished and set thre groups errno to the current value	1139	subrequests have finished and set the groups errno to the current value
770	of errno (just like calling C<errno> without an error number). By default,	1140	of errno (just like calling C<errno> without an error number). By default,
771	no argument will be passed and errno is zero.	1141	no argument will be passed and errno is zero.
772		1142
773	=item $grp->errno ([$errno])	1143	=item $grp->errno ([$errno])
774		1144
…		…
785	=item feed $grp $callback->($grp)	1155	=item feed $grp $callback->($grp)
786		1156
787	Sets a feeder/generator on this group: every group can have an attached	1157	Sets a feeder/generator on this group: every group can have an attached
788	generator that generates requests if idle. The idea behind this is that,	1158	generator that generates requests if idle. The idea behind this is that,
789	although you could just queue as many requests as you want in a group,	1159	although you could just queue as many requests as you want in a group,
790	this might starve other requests for a potentially long time. For	1160	this might starve other requests for a potentially long time. For example,
791	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>	1161	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
792	requests, delaying any later requests for a long time.	1162	delaying any later requests for a long time.
793		1163
794	To avoid this, and allow incremental generation of requests, you can	1164	To avoid this, and allow incremental generation of requests, you can
795	instead a group and set a feeder on it that generates those requests. The	1165	instead a group and set a feeder on it that generates those requests. The
796	feed callback will be called whenever there are few enough (see C<limit>,	1166	feed callback will be called whenever there are few enough (see C<limit>,
797	below) requests active in the group itself and is expected to queue more	1167	below) requests active in the group itself and is expected to queue more
…		…
801	not impose any limits).	1171	not impose any limits).
802		1172
803	If the feed does not queue more requests when called, it will be	1173	If the feed does not queue more requests when called, it will be
804	automatically removed from the group.	1174	automatically removed from the group.
805		1175
806	If the feed limit is C<0>, it will be set to C<2> automatically.	1176	If the feed limit is C<0> when this method is called, it will be set to
		1177	C<2> automatically.
807		1178
808	Example:	1179	Example:
809		1180
810	# stat all files in @files, but only ever use four aio requests concurrently:	1181	# stat all files in @files, but only ever use four aio requests concurrently:
811		1182
…		…
823	Sets the feeder limit for the group: The feeder will be called whenever	1194	Sets the feeder limit for the group: The feeder will be called whenever
824	the group contains less than this many requests.	1195	the group contains less than this many requests.
825		1196
826	Setting the limit to C<0> will pause the feeding process.	1197	Setting the limit to C<0> will pause the feeding process.
827		1198
		1199	The default value for the limit is C<0>, but note that setting a feeder
		1200	automatically bumps it up to C<2>.
		1201
828	=back	1202	=back
829		1203
830	=head2 SUPPORT FUNCTIONS	1204	=head2 SUPPORT FUNCTIONS
		1205
		1206	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
831		1207
832	=over 4	1208	=over 4
833		1209
834	=item $fileno = IO::AIO::poll_fileno	1210	=item $fileno = IO::AIO::poll_fileno
835		1211
…		…
840		1216
841	See C<poll_cb> for an example.	1217	See C<poll_cb> for an example.
842		1218
843	=item IO::AIO::poll_cb	1219	=item IO::AIO::poll_cb
844		1220
845	Process all outstanding events on the result pipe. You have to call this	1221	Process some outstanding events on the result pipe. You have to call this
846	regularly. Returns the number of events processed. Returns immediately	1222	regularly. Returns C<0> if all events could be processed, or C<-1> if it
847	when no events are outstanding.	1223	returned earlier for whatever reason. Returns immediately when no events
		1224	are outstanding. The amount of events processed depends on the settings of
		1225	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
848		1226
849	If not all requests were processed for whatever reason, the filehandle	1227	If not all requests were processed for whatever reason, the filehandle
850	will still be ready when C<poll_cb> returns.	1228	will still be ready when C<poll_cb> returns, so normally you don't have to
		1229	do anything special to have it called later.
851		1230
852	Example: Install an Event watcher that automatically calls	1231	Example: Install an Event watcher that automatically calls
853	IO::AIO::poll_cb with high priority:	1232	IO::AIO::poll_cb with high priority:
854		1233
855	Event->io (fd => IO::AIO::poll_fileno,	1234	Event->io (fd => IO::AIO::poll_fileno,
856	poll => 'r', async => 1,	1235	poll => 'r', async => 1,
857	cb => \&IO::AIO::poll_cb);	1236	cb => \&IO::AIO::poll_cb);
858		1237
859	=item IO::AIO::poll_some $max_requests	1238	=item IO::AIO::max_poll_reqs $nreqs
860		1239
861	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests	1240	=item IO::AIO::max_poll_time $seconds
862	at a time.
863		1241
864	Useful if you want to ensure some level of interactiveness when perl is	1242	These set the maximum number of requests (default C<0>, meaning infinity)
865	not fast enough to process all requests in time.	1243	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1244	the maximum amount of time (default C<0>, meaning infinity) spent in
		1245	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1246	of time C<poll_cb> is allowed to use).
		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
		1253	Setting these is useful if you want to ensure some level of
		1254	interactiveness when perl is not fast enough to process all requests in
		1255	time.
		1256
		1257	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
866		1258
867	Example: Install an Event watcher that automatically calls	1259	Example: Install an Event watcher that automatically calls
868	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
869	program get the CPU sometimes even under high AIO load.	1261	program get the CPU sometimes even under high AIO load.
870		1262
		1263	# try not to spend much more than 0.1s in poll_cb
		1264	IO::AIO::max_poll_time 0.1;
		1265
		1266	# use a low priority so other tasks have priority
871	Event->io (fd => IO::AIO::poll_fileno,	1267	Event->io (fd => IO::AIO::poll_fileno,
872	poll => 'r', nice => 1,	1268	poll => 'r', nice => 1,
873	cb => sub { IO::AIO::poll_some 256 });	1269	cb => &IO::AIO::poll_cb);
874		1270
875	=item IO::AIO::poll_wait	1271	=item IO::AIO::poll_wait
876		1272
		1273	If there are any outstanding requests and none of them in the result
877	Wait till the result filehandle becomes ready for reading (simply does a	1274	phase, wait till the result filehandle becomes ready for reading (simply
878	C<select> on the filehandle. This is useful if you want to synchronously wait	1275	does a C<select> on the filehandle. This is useful if you want to
879	for some requests to finish).	1276	synchronously wait for some requests to finish).
880		1277
881	See C<nreqs> for an example.	1278	See C<nreqs> for an example.
882		1279
		1280	=item IO::AIO::poll
		1281
		1282	Waits until some requests have been handled.
		1283
		1284	Returns the number of requests processed, but is otherwise strictly
		1285	equivalent to:
		1286
		1287	IO::AIO::poll_wait, IO::AIO::poll_cb
		1288
883	=item IO::AIO::nreqs	1289	=item IO::AIO::flush
884		1290
885	Returns the number of requests currently in the ready, execute or pending	1291	Wait till all outstanding AIO requests have been handled.
886	states (i.e. for which their callback has not been invoked yet).
887		1292
888	Example: wait till there are no outstanding requests anymore:	1293	Strictly equivalent to:
889		1294
890	IO::AIO::poll_wait, IO::AIO::poll_cb	1295	IO::AIO::poll_wait, IO::AIO::poll_cb
891	while IO::AIO::nreqs;	1296	while IO::AIO::nreqs;
892		1297
893	=item IO::AIO::nready	1298	=back
894		1299
895	Returns the number of requests currently in the ready state (not yet	1300	=head3 CONTROLLING THE NUMBER OF THREADS
896	executed).
897		1301
898	=item IO::AIO::npending	1302	=over
899
900	Returns the number of requests currently in the pending state (executed,
901	but not yet processed by poll_cb).
902
903	=item IO::AIO::flush
904
905	Wait till all outstanding AIO requests have been handled.
906
907	Strictly equivalent to:
908
909	IO::AIO::poll_wait, IO::AIO::poll_cb
910	while IO::AIO::nreqs;
911
912	=item IO::AIO::poll
913
914	Waits until some requests have been handled.
915
916	Strictly equivalent to:
917
918	IO::AIO::poll_wait, IO::AIO::poll_cb
919	if IO::AIO::nreqs;
920		1303
921	=item IO::AIO::min_parallel $nthreads	1304	=item IO::AIO::min_parallel $nthreads
922		1305
923	Set the minimum number of AIO threads to C<$nthreads>. The current	1306	Set the minimum number of AIO threads to C<$nthreads>. The current
924	default is C<8>, which means eight asynchronous operations can execute	1307	default is C<8>, which means eight asynchronous operations can execute
925	concurrently at any one time (the number of outstanding requests,	1308	concurrently at any one time (the number of outstanding requests,
926	however, is unlimited).	1309	however, is unlimited).
927		1310
928	IO::AIO starts threads only on demand, when an AIO request is queued and	1311	IO::AIO starts threads only on demand, when an AIO request is queued and
929	no free thread exists.	1312	no free thread exists. Please note that queueing up a hundred requests can
		1313	create demand for a hundred threads, even if it turns out that everything
		1314	is in the cache and could have been processed faster by a single thread.
930		1315
931	It is recommended to keep the number of threads relatively low, as some	1316	It is recommended to keep the number of threads relatively low, as some
932	Linux kernel versions will scale negatively with the number of threads	1317	Linux kernel versions will scale negatively with the number of threads
933	(higher parallelity => MUCH higher latency). With current Linux 2.6	1318	(higher parallelity => MUCH higher latency). With current Linux 2.6
934	versions, 4-32 threads should be fine.	1319	versions, 4-32 threads should be fine.
…		…
948	This module automatically runs C<max_parallel 0> at program end, to ensure	1333	This module automatically runs C<max_parallel 0> at program end, to ensure
949	that all threads are killed and that there are no outstanding requests.	1334	that all threads are killed and that there are no outstanding requests.
950		1335
951	Under normal circumstances you don't need to call this function.	1336	Under normal circumstances you don't need to call this function.
952		1337
		1338	=item IO::AIO::max_idle $nthreads
		1339
		1340	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1341	threads that did not get a request to process within 10 seconds). That
		1342	means if a thread becomes idle while C<$nthreads> other threads are also
		1343	idle, it will free its resources and exit.
		1344
		1345	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1346	to allow for extremely high load situations, but want to free resources
		1347	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1348
		1349	The default is probably ok in most situations, especially if thread
		1350	creation is fast. If thread creation is very slow on your system you might
		1351	want to use larger values.
		1352
953	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1353	=item IO::AIO::max_outstanding $maxreqs
954		1354
955	This is a very bad function to use in interactive programs because it	1355	This is a very bad function to use in interactive programs because it
956	blocks, and a bad way to reduce concurrency because it is inexact: Better	1356	blocks, and a bad way to reduce concurrency because it is inexact: Better
957	use an C<aio_group> together with a feed callback.	1357	use an C<aio_group> together with a feed callback.
958		1358
959	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1359	Sets the maximum number of outstanding requests to C<$nreqs>. If you
960	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
961	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>)
962	function will block until the limit is no longer exceeded.	1362	function will block until the limit is no longer exceeded.
963		1363
964	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
965	number of outstanding requests.	1365	number of outstanding requests.
966		1366
967	You can still queue as many requests as you want. Therefore,	1367	You can still queue as many requests as you want. Therefore,
968	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
969	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).
970		1370
971	=back	1371	=back
972		1372
		1373	=head3 STATISTICAL INFORMATION
		1374
		1375	=over
		1376
		1377	=item IO::AIO::nreqs
		1378
		1379	Returns the number of requests currently in the ready, execute or pending
		1380	states (i.e. for which their callback has not been invoked yet).
		1381
		1382	Example: wait till there are no outstanding requests anymore:
		1383
		1384	IO::AIO::poll_wait, IO::AIO::poll_cb
		1385	while IO::AIO::nreqs;
		1386
		1387	=item IO::AIO::nready
		1388
		1389	Returns the number of requests currently in the ready state (not yet
		1390	executed).
		1391
		1392	=item IO::AIO::npending
		1393
		1394	Returns the number of requests currently in the pending state (executed,
		1395	but not yet processed by poll_cb).
		1396
		1397	=back
		1398
973	=cut	1399	=cut
974		1400
975	# support function to convert a fd into a perl filehandle
976	sub _fd2fh {
977	return undef if $_[0] < 0;
978
979	# try to generate nice filehandles
980	my $sym = "IO::AIO::fd#$_[0]";
981	local *$sym;
982
983	open *$sym, "+<&=$_[0]" # usually works under any unix
984	or open *$sym, "<&=$_[0]" # cygwin needs this
985	or open *$sym, ">&=$_[0]" # or this
986	or return undef;
987
988	*$sym
989	}
990
991	min_parallel 8;	1401	min_parallel 8;
992		1402
993	END {	1403	END { flush }
994	flush;
995	};
996		1404
997	1;	1405	1;
998		1406
999	=head2 FORK BEHAVIOUR	1407	=head2 FORK BEHAVIOUR
1000		1408
…		…
1020	bytes of memory. In addition, stat requests need a stat buffer (possibly	1428	bytes of memory. In addition, stat requests need a stat buffer (possibly
1021	a few hundred bytes), readdir requires a result buffer and so on. Perl	1429	a few hundred bytes), readdir requires a result buffer and so on. Perl
1022	scalars and other data passed into aio requests will also be locked and	1430	scalars and other data passed into aio requests will also be locked and
1023	will consume memory till the request has entered the done state.	1431	will consume memory till the request has entered the done state.
1024		1432
1025	This is now awfully much, so queuing lots of requests is not usually a	1433	This is not awfully much, so queuing lots of requests is not usually a
1026	problem.	1434	problem.
1027		1435
1028	Per-thread usage:	1436	Per-thread usage:
1029		1437
1030	In the execution phase, some aio requests require more memory for	1438	In the execution phase, some aio requests require more memory for
…		…
1035		1443
1036	Known bugs will be fixed in the next release.	1444	Known bugs will be fixed in the next release.
1037		1445
1038	=head1 SEE ALSO	1446	=head1 SEE ALSO
1039		1447
1040	L<Coro::AIO>.	1448	L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
		1449	more natural syntax.
1041		1450
1042	=head1 AUTHOR	1451	=head1 AUTHOR
1043		1452
1044	Marc Lehmann <schmorp@schmorp.de>	1453	Marc Lehmann <schmorp@schmorp.de>
1045	http://home.schmorp.de/	1454	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs. Revision 1.154 by root, Sat Jun 13 14:58:33 2009 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs.
Revision 1.154 by root, Sat Jun 13 14:58:33 2009 UTC