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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.52 by root, Sat Oct 21 23:06:04 2006 UTC vs.
Revision 1.87 by root, Sun Oct 29 00:52:02 2006 UTC

…		…
15		15
16	aio_read $fh, 30000, 1024, $buffer, 0, sub {	16	aio_read $fh, 30000, 1024, $buffer, 0, sub {
17	$_[0] > 0 or die "read error: $!";	17	$_[0] > 0 or die "read error: $!";
18	};	18	};
19		19
20	use IO::AIO 2; # version has aio objects	20	# version 2+ has request and group objects
		21	use IO::AIO 2;
21		22
		23	aioreq_pri 4; # give next request a very high priority
22	my $req = aio_unlink "/tmp/file", sub { };	24	my $req = aio_unlink "/tmp/file", sub { };
23	$req->cancel; # cancel request if still in queue	25	$req->cancel; # cancel request if still in queue
24		26
25	# AnyEvent	27	my $grp = aio_group sub { print "all stats done\n" };
		28	add $grp aio_stat "..." for ...;
		29
		30	# AnyEvent integration
26	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";	31	open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
27	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });	32	my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
28		33
29	# Event	34	# Event integration
30	Event->io (fd => IO::AIO::poll_fileno,	35	Event->io (fd => IO::AIO::poll_fileno,
31	poll => 'r',	36	poll => 'r',
32	cb => \&IO::AIO::poll_cb);	37	cb => \&IO::AIO::poll_cb);
33		38
34	# Glib/Gtk2	39	# Glib/Gtk2 integration
35	add_watch Glib::IO IO::AIO::poll_fileno,	40	add_watch Glib::IO IO::AIO::poll_fileno,
36	in => sub { IO::AIO::poll_cb; 1 };	41	in => sub { IO::AIO::poll_cb; 1 };
37		42
38	# Tk	43	# Tk integration
39	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",	44	Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
40	readable => \&IO::AIO::poll_cb);	45	readable => \&IO::AIO::poll_cb);
41		46
42	# Danga::Socket	47	# Danga::Socket integration
43	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	48	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
44	\&IO::AIO::poll_cb);	49	\&IO::AIO::poll_cb);
45		50
46
47	=head1 DESCRIPTION	51	=head1 DESCRIPTION
48		52
49	This module implements asynchronous I/O using whatever means your	53	This module implements asynchronous I/O using whatever means your
50	operating system supports.	54	operating system supports.
51		55
		56	Asynchronous means that operations that can normally block your program
		57	(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
		59	is extremely useful for programs that need to stay interactive even
		60	when doing heavy I/O (GUI programs, high performance network servers
		61	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
		63	on a RAID volume or over NFS when you do a number of stat operations
		64	concurrently.
		65
		66	While this works on all types of file descriptors (for example sockets),
		67	using these functions on file descriptors that support nonblocking
		68	operation (again, sockets, pipes etc.) is very inefficient. Use an event
		69	loop for that (such as the L<Event\|Event> module): IO::AIO will naturally
		70	fit into such an event loop itself.
		71
52	Currently, a number of threads are started that execute your read/writes	72	In this version, a number of threads are started that execute your
53	and signal their completion. You don't need thread support in your libc or	73	requests and signal their completion. You don't need thread support
54	perl, and the threads created by this module will not be visible to the	74	in perl, and the threads created by this module will not be visible
55	pthreads library. In the future, this module might make use of the native	75	to perl. In the future, this module might make use of the native aio
56	aio functions available on many operating systems. However, they are often	76	functions available on many operating systems. However, they are often
57	not well-supported (Linux doesn't allow them on normal files currently,	77	not well-supported or restricted (GNU/Linux doesn't allow them on normal
58	for example), and they would only support aio_read and aio_write, so the	78	files currently, for example), and they would only support aio_read and
59	remaining functionality would have to be implemented using threads anyway.	79	aio_write, so the remaining functionality would have to be implemented
		80	using threads anyway.
60		81
61	Although the module will work with in the presence of other threads, it is	82	Although the module will work with in the presence of other (Perl-)
62	currently not reentrant, so use appropriate locking yourself, always call	83	threads, it is currently not reentrant in any way, so use appropriate
63	C<poll_cb> from within the same thread, or never call C<poll_cb> (or other	84	locking yourself, always call C<poll_cb> from within the same thread, or
64	C<aio_> functions) recursively.	85	never call C<poll_cb> (or other C<aio_> functions) recursively.
		86
		87	=head2 EXAMPLE
		88
		89	This is a simple example that uses the Event module and loads
		90	F</etc/passwd> asynchronously:
		91
		92	use Fcntl;
		93	use Event;
		94	use IO::AIO;
		95
		96	# register the IO::AIO callback with Event
		97	Event->io (fd => IO::AIO::poll_fileno,
		98	poll => 'r',
		99	cb => \&IO::AIO::poll_cb);
		100
		101	# queue the request to open /etc/passwd
		102	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		103	my $fh = $_[0]
		104	or die "error while opening: $!";
		105
		106	# stat'ing filehandles is generally non-blocking
		107	my $size = -s $fh;
		108
		109	# queue a request to read the file
		110	my $contents;
		111	aio_read $fh, 0, $size, $contents, 0, sub {
		112	$_[0] == $size
		113	or die "short read: $!";
		114
		115	close $fh;
		116
		117	# file contents now in $contents
		118	print $contents;
		119
		120	# exit event loop and program
		121	Event::unloop;
		122	};
		123	};
		124
		125	# possibly queue up other requests, or open GUI windows,
		126	# check for sockets etc. etc.
		127
		128	# process events as long as there are some:
		129	Event::loop;
		130
		131	=head1 REQUEST ANATOMY AND LIFETIME
		132
		133	Every C<aio_*> function creates a request. which is a C data structure not
		134	directly visible to Perl.
		135
		136	If called in non-void context, every request function returns a Perl
		137	object representing the request. In void context, nothing is returned,
		138	which saves a bit of memory.
		139
		140	The perl object is a fairly standard ref-to-hash object. The hash contents
		141	are not used by IO::AIO so you are free to store anything you like in it.
		142
		143	During their existance, aio requests travel through the following states,
		144	in order:
		145
		146	=over 4
		147
		148	=item ready
		149
		150	Immediately after a request is created it is put into the ready state,
		151	waiting for a thread to execute it.
		152
		153	=item execute
		154
		155	A thread has accepted the request for processing and is currently
		156	executing it (e.g. blocking in read).
		157
		158	=item pending
		159
		160	The request has been executed and is waiting for result processing.
		161
		162	While request submission and execution is fully asynchronous, result
		163	processing is not and relies on the perl interpreter calling C<poll_cb>
		164	(or another function with the same effect).
		165
		166	=item result
		167
		168	The request results are processed synchronously by C<poll_cb>.
		169
		170	The C<poll_cb> function will process all outstanding aio requests by
		171	calling their callbacks, freeing memory associated with them and managing
		172	any groups they are contained in.
		173
		174	=item done
		175
		176	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
		178	aio request is severed and calling its methods will either do nothing or
		179	result in a runtime error).
65		180
66	=cut	181	=cut
67		182
68	package IO::AIO;	183	package IO::AIO;
69		184
…		…
71	use strict 'vars';	186	use strict 'vars';
72		187
73	use base 'Exporter';	188	use base 'Exporter';
74		189
75	BEGIN {	190	BEGIN {
76	our $VERSION = '1.8';	191	our $VERSION = '2.1';
77		192
78	our @EXPORT = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	193	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
79	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	194	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
80	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move);	195	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move
81	our @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);	196	aio_copy aio_group aio_nop aio_mknod);
		197	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
		198	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
		199	min_parallel max_parallel max_idle
		200	nreqs nready npending nthreads
		201	max_poll_time max_poll_reqs);
		202
		203	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
82		204
83	require XSLoader;	205	require XSLoader;
84	XSLoader::load ("IO::AIO", $VERSION);	206	XSLoader::load ("IO::AIO", $VERSION);
85	}	207	}
86		208
87	=head1 FUNCTIONS	209	=head1 FUNCTIONS
88		210
89	=head2 AIO FUNCTIONS	211	=head2 AIO REQUEST FUNCTIONS
90		212
91	All the C<aio_*> calls are more or less thin wrappers around the syscall	213	All the C<aio_*> calls are more or less thin wrappers around the syscall
92	with the same name (sans C<aio_>). The arguments are similar or identical,	214	with the same name (sans C<aio_>). The arguments are similar or identical,
93	and they all accept an additional (and optional) C<$callback> argument	215	and they all accept an additional (and optional) C<$callback> argument
94	which must be a code reference. This code reference will get called with	216	which must be a code reference. This code reference will get called with
…		…
97	syscall has been executed asynchronously.	219	syscall has been executed asynchronously.
98		220
99	All functions expecting a filehandle keep a copy of the filehandle	221	All functions expecting a filehandle keep a copy of the filehandle
100	internally until the request has finished.	222	internally until the request has finished.
101		223
102	All non-composite requests (requests that are not broken down into
103	multiple requests) return objects of type L<IO::AIO::REQ> that allow	224	All functions return request objects of type L<IO::AIO::REQ> that allow
104	further manipulation of running requests.	225	further manipulation of those requests while they are in-flight.
105		226
106	The pathnames you pass to these routines I<must> be absolute and	227	The pathnames you pass to these routines I<must> be absolute and
107	encoded in byte form. The reason for the former is that at the time the	228	encoded as octets. The reason for the former is that at the time the
108	request is being executed, the current working directory could have	229	request is being executed, the current working directory could have
109	changed. Alternatively, you can make sure that you never change the	230	changed. Alternatively, you can make sure that you never change the
110	current working directory.	231	current working directory anywhere in the program and then use relative
		232	paths.
111		233
112	To encode pathnames to byte form, either make sure you either: a)	234	To encode pathnames as octets, either make sure you either: a) always pass
113	always pass in filenames you got from outside (command line, readdir	235	in filenames you got from outside (command line, readdir etc.) without
114	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	236	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
115	your pathnames to the locale (or other) encoding in effect in the user	237	your pathnames to the locale (or other) encoding in effect in the user
116	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	238	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
117	use something else.	239	use something else to ensure your scalar has the correct contents.
		240
		241	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		242	handles correctly wether it is set or not.
118		243
119	=over 4	244	=over 4
		245
		246	=item $prev_pri = aioreq_pri [$pri]
		247
		248	Returns the priority value that would be used for the next request and, if
		249	C<$pri> is given, sets the priority for the next aio request.
		250
		251	The default priority is C<0>, the minimum and maximum priorities are C<-4>
		252	and C<4>, respectively. Requests with higher priority will be serviced
		253	first.
		254
		255	The priority will be reset to C<0> after each call to one of the C<aio_*>
		256	functions.
		257
		258	Example: open a file with low priority, then read something from it with
		259	higher priority so the read request is serviced before other low priority
		260	open requests (potentially spamming the cache):
		261
		262	aioreq_pri -3;
		263	aio_open ..., sub {
		264	return unless $_[0];
		265
		266	aioreq_pri -2;
		267	aio_read $_[0], ..., sub {
		268	...
		269	};
		270	};
		271
		272	=item aioreq_nice $pri_adjust
		273
		274	Similar to C<aioreq_pri>, but subtracts the given value from the current
		275	priority, so the effect is cumulative.
120		276
121	=item aio_open $pathname, $flags, $mode, $callback->($fh)	277	=item aio_open $pathname, $flags, $mode, $callback->($fh)
122		278
123	Asynchronously open or create a file and call the callback with a newly	279	Asynchronously open or create a file and call the callback with a newly
124	created filehandle for the file.	280	created filehandle for the file.
…		…
174		330
175	aio_read $fh, 7, 15, $buffer, 0, sub {	331	aio_read $fh, 7, 15, $buffer, 0, sub {
176	$_[0] > 0 or die "read error: $!";	332	$_[0] > 0 or die "read error: $!";
177	print "read $_[0] bytes: <$buffer>\n";	333	print "read $_[0] bytes: <$buffer>\n";
178	};	334	};
179
180	=item aio_move $srcpath, $dstpath, $callback->($status)
181
182	Try to move the I<file> (directories not supported as either source or
183	destination) from C<$srcpath> to C<$dstpath> and call the callback with
184	the C<0> (error) or C<-1> ok.
185
186	This is a composite request that tries to rename(2) the file first. If
187	rename files with C<EXDEV>, it creates the destination file with mode 0200
188	and copies the contents of the source file into it using C<aio_sendfile>,
189	followed by restoring atime, mtime, access mode and uid/gid, in that
190	order, and unlinking the C<$srcpath>.
191
192	If an error occurs, the partial destination file will be unlinked, if
193	possible, except when setting atime, mtime, access mode and uid/gid, where
194	errors are being ignored.
195
196	=cut
197
198	sub aio_move($$$) {
199	my ($src, $dst, $cb) = @_;
200
201	aio_rename $src, $dst, sub {
202	if ($_[0] && $! == EXDEV) {
203	aio_open $src, O_RDONLY, 0, sub {
204	if (my $src_fh = $_[0]) {
205	my @stat = stat $src_fh;
206
207	aio_open $dst, O_WRONLY, 0200, sub {
208	if (my $dst_fh = $_[0]) {
209	aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
210	close $src_fh;
211
212	if ($_[0] == $stat[7]) {
213	utime $stat[8], $stat[9], $dst;
214	chmod $stat[2] & 07777, $dst_fh;
215	chown $stat[4], $stat[5], $dst_fh;
216	close $dst_fh;
217
218	aio_unlink $src, sub {
219	$cb->($_[0]);
220	};
221	} else {
222	my $errno = $!;
223	aio_unlink $dst, sub {
224	$! = $errno;
225	$cb->(-1);
226	};
227	}
228	};
229	} else {
230	$cb->(-1);
231	}
232	},
233
234	} else {
235	$cb->(-1);
236	}
237	};
238	} else {
239	$cb->($_[0]);
240	}
241	};
242	}
243		335
244	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	336	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
245		337
246	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	338	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
247	reading at byte offset C<$in_offset>, and starts writing at the current	339	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
303	=item aio_unlink $pathname, $callback->($status)	395	=item aio_unlink $pathname, $callback->($status)
304		396
305	Asynchronously unlink (delete) a file and call the callback with the	397	Asynchronously unlink (delete) a file and call the callback with the
306	result code.	398	result code.
307		399
		400	=item aio_mknod $path, $mode, $dev, $callback->($status)
		401
		402	[EXPERIMENTAL]
		403
		404	Asynchronously create a device node (or fifo). See mknod(2).
		405
		406	The only (POSIX-) portable way of calling this function is:
		407
		408	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		409
308	=item aio_link $srcpath, $dstpath, $callback->($status)	410	=item aio_link $srcpath, $dstpath, $callback->($status)
309		411
310	Asynchronously create a new link to the existing object at C<$srcpath> at	412	Asynchronously create a new link to the existing object at C<$srcpath> at
311	the path C<$dstpath> and call the callback with the result code.	413	the path C<$dstpath> and call the callback with the result code.
312		414
…		…
332	sorted, and will B<NOT> include the C<.> and C<..> entries.	434	sorted, and will B<NOT> include the C<.> and C<..> entries.
333		435
334	The callback a single argument which is either C<undef> or an array-ref	436	The callback a single argument which is either C<undef> or an array-ref
335	with the filenames.	437	with the filenames.
336		438
		439	=item aio_copy $srcpath, $dstpath, $callback->($status)
		440
		441	Try to copy the I<file> (directories not supported as either source or
		442	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		443	the C<0> (error) or C<-1> ok.
		444
		445	This is a composite request that it creates the destination file with
		446	mode 0200 and copies the contents of the source file into it using
		447	C<aio_sendfile>, followed by restoring atime, mtime, access mode and
		448	uid/gid, in that order.
		449
		450	If an error occurs, the partial destination file will be unlinked, if
		451	possible, except when setting atime, mtime, access mode and uid/gid, where
		452	errors are being ignored.
		453
		454	=cut
		455
		456	sub aio_copy($$;$) {
		457	my ($src, $dst, $cb) = @_;
		458
		459	my $pri = aioreq_pri;
		460	my $grp = aio_group $cb;
		461
		462	aioreq_pri $pri;
		463	add $grp aio_open $src, O_RDONLY, 0, sub {
		464	if (my $src_fh = $_[0]) {
		465	my @stat = stat $src_fh;
		466
		467	aioreq_pri $pri;
		468	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
		469	if (my $dst_fh = $_[0]) {
		470	aioreq_pri $pri;
		471	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
		472	if ($_[0] == $stat[7]) {
		473	$grp->result (0);
		474	close $src_fh;
		475
		476	# those should not normally block. should. should.
		477	utime $stat[8], $stat[9], $dst;
		478	chmod $stat[2] & 07777, $dst_fh;
		479	chown $stat[4], $stat[5], $dst_fh;
		480	close $dst_fh;
		481	} else {
		482	$grp->result (-1);
		483	close $src_fh;
		484	close $dst_fh;
		485
		486	aioreq $pri;
		487	add $grp aio_unlink $dst;
		488	}
		489	};
		490	} else {
		491	$grp->result (-1);
		492	}
		493	},
		494
		495	} else {
		496	$grp->result (-1);
		497	}
		498	};
		499
		500	$grp
		501	}
		502
		503	=item aio_move $srcpath, $dstpath, $callback->($status)
		504
		505	Try to move the I<file> (directories not supported as either source or
		506	destination) from C<$srcpath> to C<$dstpath> and call the callback with
		507	the C<0> (error) or C<-1> ok.
		508
		509	This is a composite request that tries to rename(2) the file first. If
		510	rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
		511	that is successful, unlinking the C<$srcpath>.
		512
		513	=cut
		514
		515	sub aio_move($$;$) {
		516	my ($src, $dst, $cb) = @_;
		517
		518	my $pri = aioreq_pri;
		519	my $grp = aio_group $cb;
		520
		521	aioreq_pri $pri;
		522	add $grp aio_rename $src, $dst, sub {
		523	if ($_[0] && $! == EXDEV) {
		524	aioreq_pri $pri;
		525	add $grp aio_copy $src, $dst, sub {
		526	$grp->result ($_[0]);
		527
		528	if (!$_[0]) {
		529	aioreq_pri $pri;
		530	add $grp aio_unlink $src;
		531	}
		532	};
		533	} else {
		534	$grp->result ($_[0]);
		535	}
		536	};
		537
		538	$grp
		539	}
		540
337	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	541	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
338		542
339	Scans a directory (similar to C<aio_readdir>) but additionally tries to	543	Scans a directory (similar to C<aio_readdir>) but additionally tries to
340	separate the entries of directory C<$path> into two sets of names, ones	544	efficiently separate the entries of directory C<$path> into two sets of
341	you can recurse into (directories or links to them), and ones you cannot	545	names, directories you can recurse into (directories), and ones you cannot
342	recurse into (everything else).	546	recurse into (everything else, including symlinks to directories).
343		547
344	C<aio_scandir> is a composite request that consists of many sub	548	C<aio_scandir> is a composite request that creates of many sub requests_
345	requests. C<$maxreq> specifies the maximum number of outstanding aio	549	C<$maxreq> specifies the maximum number of outstanding aio requests that
346	requests that this function generates. If it is C<< <= 0 >>, then a	550	this function generates. If it is C<< <= 0 >>, then a suitable default
347	suitable default will be chosen (currently 8).	551	will be chosen (currently 4).
348		552
349	On error, the callback is called without arguments, otherwise it receives	553	On error, the callback is called without arguments, otherwise it receives
350	two array-refs with path-relative entry names.	554	two array-refs with path-relative entry names.
351		555
352	Example:	556	Example:
…		…
389	=cut	593	=cut
390		594
391	sub aio_scandir($$$) {	595	sub aio_scandir($$$) {
392	my ($path, $maxreq, $cb) = @_;	596	my ($path, $maxreq, $cb) = @_;
393		597
		598	my $pri = aioreq_pri;
		599
		600	my $grp = aio_group $cb;
		601
394	$maxreq = 8 if $maxreq <= 0;	602	$maxreq = 4 if $maxreq <= 0;
395		603
396	# stat once	604	# stat once
		605	aioreq_pri $pri;
397	aio_stat $path, sub {	606	add $grp aio_stat $path, sub {
398	return $cb->() if $_[0];	607	return $grp->result () if $_[0];
399	my $now = time;	608	my $now = time;
400	my $hash1 = join ":", (stat _)[0,1,3,7,9];	609	my $hash1 = join ":", (stat _)[0,1,3,7,9];
401		610
402	# read the directory entries	611	# read the directory entries
		612	aioreq_pri $pri;
403	aio_readdir $path, sub {	613	add $grp aio_readdir $path, sub {
404	my $entries = shift	614	my $entries = shift
405	or return $cb->();	615	or return $grp->result ();
406		616
407	# stat the dir another time	617	# stat the dir another time
		618	aioreq_pri $pri;
408	aio_stat $path, sub {	619	add $grp aio_stat $path, sub {
409	my $hash2 = join ":", (stat _)[0,1,3,7,9];	620	my $hash2 = join ":", (stat _)[0,1,3,7,9];
410		621
411	my $ndirs;	622	my $ndirs;
412		623
413	# take the slow route if anything looks fishy	624	# take the slow route if anything looks fishy
…		…
415	$ndirs = -1;	626	$ndirs = -1;
416	} else {	627	} else {
417	# if nlink == 2, we are finished	628	# if nlink == 2, we are finished
418	# on non-posix-fs's, we rely on nlink < 2	629	# on non-posix-fs's, we rely on nlink < 2
419	$ndirs = (stat _)[3] - 2	630	$ndirs = (stat _)[3] - 2
420	or return $cb->([], $entries);	631	or return $grp->result ([], $entries);
421	}	632	}
422		633
423	# sort into likely dirs and likely nondirs	634	# sort into likely dirs and likely nondirs
424	# dirs == files without ".", short entries first	635	# dirs == files without ".", short entries first
425	$entries = [map $_->[0],	636	$entries = [map $_->[0],
…		…
427	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	638	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
428	@$entries];	639	@$entries];
429		640
430	my (@dirs, @nondirs);	641	my (@dirs, @nondirs);
431		642
432	my ($statcb, $schedcb);	643	my $statgrp = add $grp aio_group sub {
433	my $nreq = 0;	644	$grp->result (\@dirs, \@nondirs);
		645	};
434		646
435	$schedcb = sub {	647	limit $statgrp $maxreq;
436	if (@$entries) {	648	feed $statgrp sub {
437	if ($nreq < $maxreq) {	649	return unless @$entries;
438	my $ent = pop @$entries;	650	my $entry = pop @$entries;
		651
		652	aioreq_pri $pri;
		653	add $statgrp aio_stat "$path/$entry/.", sub {
		654	if ($_[0] < 0) {
		655	push @nondirs, $entry;
		656	} else {
		657	# need to check for real directory
		658	aioreq_pri $pri;
		659	add $statgrp aio_lstat "$path/$entry", sub {
		660	if (-d _) {
		661	push @dirs, $entry;
		662
		663	unless (--$ndirs) {
		664	push @nondirs, @$entries;
		665	feed $statgrp;
		666	}
		667	} else {
		668	push @nondirs, $entry;
		669	}
439	$nreq++;	670	}
440	aio_stat "$path/$ent/.", sub { $statcb->($_[0], $ent) };
441	}	671	}
442	} elsif (!$nreq) {
443	# finished
444	undef $statcb;
445	undef $schedcb;
446	$cb->(\@dirs, \@nondirs) if $cb;
447	undef $cb;
448	}	672	};
449	};	673	};
450	$statcb = sub {
451	my ($status, $entry) = @_;
452
453	if ($status < 0) {
454	$nreq--;
455	push @nondirs, $entry;
456	&$schedcb;
457	} else {
458	# need to check for real directory
459	aio_lstat "$path/$entry", sub {
460	$nreq--;
461
462	if (-d _) {
463	push @dirs, $entry;
464
465	if (!--$ndirs) {
466	push @nondirs, @$entries;
467	$entries = [];
468	}
469	} else {
470	push @nondirs, $entry;
471	}
472
473	&$schedcb;
474	}
475	}
476	};
477
478	&$schedcb while @$entries && $nreq < $maxreq;
479	};	674	};
480	};	675	};
481	};	676	};
		677
		678	$grp
482	}	679	}
483		680
484	=item aio_fsync $fh, $callback->($status)	681	=item aio_fsync $fh, $callback->($status)
485		682
486	Asynchronously call fsync on the given filehandle and call the callback	683	Asynchronously call fsync on the given filehandle and call the callback
…		…
492	callback with the fdatasync result code.	689	callback with the fdatasync result code.
493		690
494	If this call isn't available because your OS lacks it or it couldn't be	691	If this call isn't available because your OS lacks it or it couldn't be
495	detected, it will be emulated by calling C<fsync> instead.	692	detected, it will be emulated by calling C<fsync> instead.
496		693
		694	=item aio_group $callback->(...)
		695
		696	This is a very special aio request: Instead of doing something, it is a
		697	container for other aio requests, which is useful if you want to bundle
		698	many requests into a single, composite, request with a definite callback
		699	and the ability to cancel the whole request with its subrequests.
		700
		701	Returns an object of class L<IO::AIO::GRP>. See its documentation below
		702	for more info.
		703
		704	Example:
		705
		706	my $grp = aio_group sub {
		707	print "all stats done\n";
		708	};
		709
		710	add $grp
		711	(aio_stat ...),
		712	(aio_stat ...),
		713	...;
		714
		715	=item aio_nop $callback->()
		716
		717	This is a special request - it does nothing in itself and is only used for
		718	side effects, such as when you want to add a dummy request to a group so
		719	that finishing the requests in the group depends on executing the given
		720	code.
		721
		722	While this request does nothing, it still goes through the execution
		723	phase and still requires a worker thread. Thus, the callback will not
		724	be executed immediately but only after other requests in the queue have
		725	entered their execution phase. This can be used to measure request
		726	latency.
		727
		728	=item IO::AIO::aio_busy $fractional_seconds, $callback->() NOT EXPORTED
		729
		730	Mainly used for debugging and benchmarking, this aio request puts one of
		731	the request workers to sleep for the given time.
		732
		733	While it is theoretically handy to have simple I/O scheduling requests
		734	like sleep and file handle readable/writable, the overhead this creates is
		735	immense (it blocks a thread for a long time) so do not use this function
		736	except to put your application under artificial I/O pressure.
		737
497	=back	738	=back
498		739
499	=head2 IO::AIO::CB CLASS	740	=head2 IO::AIO::REQ CLASS
500		741
501	All non-aggregate C<aio_*> functions return an object of this class when	742	All non-aggregate C<aio_*> functions return an object of this class when
502	called in non-void context.	743	called in non-void context.
503		744
504	A request always moves through the following five states in its lifetime,
505	in order: B<ready> (request has been created, but has not been executed
506	yet), B<execute> (request is currently being executed), B<pending>
507	(request has been executed but callback has not been called yet),
508	B<result> (results are being processed synchronously, includes calling the
509	callback) and B<done> (request has reached the end of its lifetime and
510	holds no resources anymore).
511
512	=over 4	745	=over 4
513		746
514	=item $req->cancel	747	=item cancel $req
515		748
516	Cancels the request, if possible. Has the effect of skipping execution	749	Cancels the request, if possible. Has the effect of skipping execution
517	when entering the B<execute> state and skipping calling the callback when	750	when entering the B<execute> state and skipping calling the callback when
518	entering the the B<result> state, but will leave the request otherwise	751	entering the the B<result> state, but will leave the request otherwise
519	untouched. That means that requests that currently execute will not be	752	untouched. That means that requests that currently execute will not be
520	stopped and resources held by the request will not be freed prematurely.	753	stopped and resources held by the request will not be freed prematurely.
521		754
		755	=item cb $req $callback->(...)
		756
		757	Replace (or simply set) the callback registered to the request.
		758
522	=back	759	=back
523		760
		761	=head2 IO::AIO::GRP CLASS
		762
		763	This class is a subclass of L<IO::AIO::REQ>, so all its methods apply to
		764	objects of this class, too.
		765
		766	A IO::AIO::GRP object is a special request that can contain multiple other
		767	aio requests.
		768
		769	You create one by calling the C<aio_group> constructing function with a
		770	callback that will be called when all contained requests have entered the
		771	C<done> state:
		772
		773	my $grp = aio_group sub {
		774	print "all requests are done\n";
		775	};
		776
		777	You add requests by calling the C<add> method with one or more
		778	C<IO::AIO::REQ> objects:
		779
		780	$grp->add (aio_unlink "...");
		781
		782	add $grp aio_stat "...", sub {
		783	$_[0] or return $grp->result ("error");
		784
		785	# add another request dynamically, if first succeeded
		786	add $grp aio_open "...", sub {
		787	$grp->result ("ok");
		788	};
		789	};
		790
		791	This makes it very easy to create composite requests (see the source of
		792	C<aio_move> for an application) that work and feel like simple requests.
		793
		794	=over 4
		795
		796	=item * The IO::AIO::GRP objects will be cleaned up during calls to
		797	C<IO::AIO::poll_cb>, just like any other request.
		798
		799	=item * They can be canceled like any other request. Canceling will cancel not
		800	only the request itself, but also all requests it contains.
		801
		802	=item * They can also can also be added to other IO::AIO::GRP objects.
		803
		804	=item * You must not add requests to a group from within the group callback (or
		805	any later time).
		806
		807	=back
		808
		809	Their lifetime, simplified, looks like this: when they are empty, they
		810	will finish very quickly. If they contain only requests that are in the
		811	C<done> state, they will also finish. Otherwise they will continue to
		812	exist.
		813
		814	That means after creating a group you have some time to add requests. And
		815	in the callbacks of those requests, you can add further requests to the
		816	group. And only when all those requests have finished will the the group
		817	itself finish.
		818
		819	=over 4
		820
		821	=item add $grp ...
		822
		823	=item $grp->add (...)
		824
		825	Add one or more requests to the group. Any type of L<IO::AIO::REQ> can
		826	be added, including other groups, as long as you do not create circular
		827	dependencies.
		828
		829	Returns all its arguments.
		830
		831	=item $grp->cancel_subs
		832
		833	Cancel all subrequests and clears any feeder, but not the group request
		834	itself. Useful when you queued a lot of events but got a result early.
		835
		836	=item $grp->result (...)
		837
		838	Set the result value(s) that will be passed to the group callback when all
		839	subrequests have finished and set thre groups errno to the current value
		840	of errno (just like calling C<errno> without an error number). By default,
		841	no argument will be passed and errno is zero.
		842
		843	=item $grp->errno ([$errno])
		844
		845	Sets the group errno value to C<$errno>, or the current value of errno
		846	when the argument is missing.
		847
		848	Every aio request has an associated errno value that is restored when
		849	the callback is invoked. This method lets you change this value from its
		850	default (0).
		851
		852	Calling C<result> will also set errno, so make sure you either set C<$!>
		853	before the call to C<result>, or call c<errno> after it.
		854
		855	=item feed $grp $callback->($grp)
		856
		857	Sets a feeder/generator on this group: every group can have an attached
		858	generator that generates requests if idle. The idea behind this is that,
		859	although you could just queue as many requests as you want in a group,
		860	this might starve other requests for a potentially long time. For
		861	example, C<aio_scandir> might generate hundreds of thousands C<aio_stat>
		862	requests, delaying any later requests for a long time.
		863
		864	To avoid this, and allow incremental generation of requests, you can
		865	instead a group and set a feeder on it that generates those requests. The
		866	feed callback will be called whenever there are few enough (see C<limit>,
		867	below) requests active in the group itself and is expected to queue more
		868	requests.
		869
		870	The feed callback can queue as many requests as it likes (i.e. C<add> does
		871	not impose any limits).
		872
		873	If the feed does not queue more requests when called, it will be
		874	automatically removed from the group.
		875
		876	If the feed limit is C<0>, it will be set to C<2> automatically.
		877
		878	Example:
		879
		880	# stat all files in @files, but only ever use four aio requests concurrently:
		881
		882	my $grp = aio_group sub { print "finished\n" };
		883	limit $grp 4;
		884	feed $grp sub {
		885	my $file = pop @files
		886	or return;
		887
		888	add $grp aio_stat $file, sub { ... };
		889	};
		890
		891	=item limit $grp $num
		892
		893	Sets the feeder limit for the group: The feeder will be called whenever
		894	the group contains less than this many requests.
		895
		896	Setting the limit to C<0> will pause the feeding process.
		897
		898	=back
		899
524	=head2 SUPPORT FUNCTIONS	900	=head2 SUPPORT FUNCTIONS
		901
		902	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
525		903
526	=over 4	904	=over 4
527		905
528	=item $fileno = IO::AIO::poll_fileno	906	=item $fileno = IO::AIO::poll_fileno
529		907
…		…
534		912
535	See C<poll_cb> for an example.	913	See C<poll_cb> for an example.
536		914
537	=item IO::AIO::poll_cb	915	=item IO::AIO::poll_cb
538		916
539	Process all outstanding events on the result pipe. You have to call this	917	Process some outstanding events on the result pipe. You have to call this
540	regularly. Returns the number of events processed. Returns immediately	918	regularly. Returns the number of events processed. Returns immediately
541	when no events are outstanding.	919	when no events are outstanding. The amount of events processed depends on
		920	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
		921
		922	If not all requests were processed for whatever reason, the filehandle
		923	will still be ready when C<poll_cb> returns.
542		924
543	Example: Install an Event watcher that automatically calls	925	Example: Install an Event watcher that automatically calls
544	IO::AIO::poll_cb with high priority:	926	IO::AIO::poll_cb with high priority:
545		927
546	Event->io (fd => IO::AIO::poll_fileno,	928	Event->io (fd => IO::AIO::poll_fileno,
547	poll => 'r', async => 1,	929	poll => 'r', async => 1,
548	cb => \&IO::AIO::poll_cb);	930	cb => \&IO::AIO::poll_cb);
549		931
		932	=item IO::AIO::max_poll_reqs $nreqs
		933
		934	=item IO::AIO::max_poll_time $seconds
		935
		936	These set the maximum number of requests (default C<0>, meaning infinity)
		937	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		938	the maximum amount of time (default C<0>, meaning infinity) spent in
		939	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		940	of time C<poll_cb> is allowed to use).
		941
		942	Setting these is useful if you want to ensure some level of
		943	interactiveness when perl is not fast enough to process all requests in
		944	time.
		945
		946	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
		947
		948	Example: Install an Event watcher that automatically calls
		949	IO::AIO::poll_some with low priority, to ensure that other parts of the
		950	program get the CPU sometimes even under high AIO load.
		951
		952	# try not to spend much more than 0.1s in poll_cb
		953	IO::AIO::max_poll_time 0.1;
		954
		955	# use a low priority so other tasks have priority
		956	Event->io (fd => IO::AIO::poll_fileno,
		957	poll => 'r', nice => 1,
		958	cb => &IO::AIO::poll_cb);
		959
550	=item IO::AIO::poll_wait	960	=item IO::AIO::poll_wait
551		961
552	Wait till the result filehandle becomes ready for reading (simply does a	962	Wait till the result filehandle becomes ready for reading (simply does a
553	C<select> on the filehandle. This is useful if you want to synchronously wait	963	C<select> on the filehandle. This is useful if you want to synchronously
554	for some requests to finish).	964	wait for some requests to finish).
555		965
556	See C<nreqs> for an example.	966	See C<nreqs> for an example.
557		967
		968	=item IO::AIO::poll
		969
		970	Waits until some requests have been handled.
		971
		972	Strictly equivalent to:
		973
		974	IO::AIO::poll_wait, IO::AIO::poll_cb
		975	if IO::AIO::nreqs;
		976
558	=item IO::AIO::nreqs	977	=item IO::AIO::flush
559		978
560	Returns the number of requests currently outstanding (i.e. for which their	979	Wait till all outstanding AIO requests have been handled.
561	callback has not been invoked yet).
562		980
563	Example: wait till there are no outstanding requests anymore:	981	Strictly equivalent to:
564		982
565	IO::AIO::poll_wait, IO::AIO::poll_cb	983	IO::AIO::poll_wait, IO::AIO::poll_cb
566	while IO::AIO::nreqs;	984	while IO::AIO::nreqs;
567		985
568	=item IO::AIO::flush	986	=head3 CONTROLLING THE NUMBER OF THREADS
569
570	Wait till all outstanding AIO requests have been handled.
571
572	Strictly equivalent to:
573
574	IO::AIO::poll_wait, IO::AIO::poll_cb
575	while IO::AIO::nreqs;
576
577	=item IO::AIO::poll
578
579	Waits until some requests have been handled.
580
581	Strictly equivalent to:
582
583	IO::AIO::poll_wait, IO::AIO::poll_cb
584	if IO::AIO::nreqs;
585		987
586	=item IO::AIO::min_parallel $nthreads	988	=item IO::AIO::min_parallel $nthreads
587		989
588	Set the minimum number of AIO threads to C<$nthreads>. The current default	990	Set the minimum number of AIO threads to C<$nthreads>. The current
589	is C<4>, which means four asynchronous operations can be done at one time	991	default is C<8>, which means eight asynchronous operations can execute
590	(the number of outstanding operations, however, is unlimited).	992	concurrently at any one time (the number of outstanding requests,
		993	however, is unlimited).
591		994
592	IO::AIO starts threads only on demand, when an AIO request is queued and	995	IO::AIO starts threads only on demand, when an AIO request is queued and
593	no free thread exists.	996	no free thread exists. Please note that queueing up a hundred requests can
		997	create demand for a hundred threads, even if it turns out that everything
		998	is in the cache and could have been processed faster by a single thread.
594		999
595	It is recommended to keep the number of threads low, as some Linux	1000	It is recommended to keep the number of threads relatively low, as some
596	kernel versions will scale negatively with the number of threads (higher	1001	Linux kernel versions will scale negatively with the number of threads
597	parallelity => MUCH higher latency). With current Linux 2.6 versions, 4-32	1002	(higher parallelity => MUCH higher latency). With current Linux 2.6
598	threads should be fine.	1003	versions, 4-32 threads should be fine.
599		1004
600	Under most circumstances you don't need to call this function, as the	1005	Under most circumstances you don't need to call this function, as the
601	module selects a default that is suitable for low to moderate load.	1006	module selects a default that is suitable for low to moderate load.
602		1007
603	=item IO::AIO::max_parallel $nthreads	1008	=item IO::AIO::max_parallel $nthreads
…		…
612	This module automatically runs C<max_parallel 0> at program end, to ensure	1017	This module automatically runs C<max_parallel 0> at program end, to ensure
613	that all threads are killed and that there are no outstanding requests.	1018	that all threads are killed and that there are no outstanding requests.
614		1019
615	Under normal circumstances you don't need to call this function.	1020	Under normal circumstances you don't need to call this function.
616		1021
		1022	=item IO::AIO::max_idle $nthreads
		1023
		1024	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1025	threads that did not get a request to process within 10 seconds). That
		1026	means if a thread becomes idle while C<$nthreads> other threads are also
		1027	idle, it will free its resources and exit.
		1028
		1029	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1030	to allow for extremely high load situations, but want to free resources
		1031	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1032
		1033	The default is probably ok in most situations, especially if thread
		1034	creation is fast. If thread creation is very slow on your system you might
		1035	want to use larger values.
		1036
617	=item $oldnreqs = IO::AIO::max_outstanding $nreqs	1037	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
		1038
		1039	This is a very bad function to use in interactive programs because it
		1040	blocks, and a bad way to reduce concurrency because it is inexact: Better
		1041	use an C<aio_group> together with a feed callback.
618		1042
619	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1043	Sets the maximum number of outstanding requests to C<$nreqs>. If you
620	try to queue up more than this number of requests, the caller will block until	1044	to queue up more than this number of requests, the next call to the
621	some requests have been handled.	1045	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
		1046	function will block until the limit is no longer exceeded.
622		1047
623	The default is very large, so normally there is no practical limit. If you	1048	The default value is very large, so there is no practical limit on the
624	queue up many requests in a loop it often improves speed if you set	1049	number of outstanding requests.
625	this to a relatively low number, such as C<100>.
626		1050
627	Under normal circumstances you don't need to call this function.	1051	You can still queue as many requests as you want. Therefore,
		1052	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
		1053	as a stop gap to shield against fatal memory overflow (with large values).
		1054
		1055	=head3 STATISTICAL INFORMATION
		1056
		1057	=item IO::AIO::nreqs
		1058
		1059	Returns the number of requests currently in the ready, execute or pending
		1060	states (i.e. for which their callback has not been invoked yet).
		1061
		1062	Example: wait till there are no outstanding requests anymore:
		1063
		1064	IO::AIO::poll_wait, IO::AIO::poll_cb
		1065	while IO::AIO::nreqs;
		1066
		1067	=item IO::AIO::nready
		1068
		1069	Returns the number of requests currently in the ready state (not yet
		1070	executed).
		1071
		1072	=item IO::AIO::npending
		1073
		1074	Returns the number of requests currently in the pending state (executed,
		1075	but not yet processed by poll_cb).
628		1076
629	=back	1077	=back
630		1078
631	=cut	1079	=cut
632		1080
…		…
644	or return undef;	1092	or return undef;
645		1093
646	*$sym	1094	*$sym
647	}	1095	}
648		1096
649	min_parallel 4;	1097	min_parallel 8;
650		1098
651	END {	1099	END {
652	max_parallel 0;	1100	min_parallel 1;
653	}	1101	flush;
		1102	};
654		1103
655	1;	1104	1;
656		1105
657	=head2 FORK BEHAVIOUR	1106	=head2 FORK BEHAVIOUR
658		1107
659	This module should do "the right thing" when the process using it forks:	1108	This module should do "the right thing" when the process using it forks:
660		1109
661	Before the fork, IO::AIO enters a quiescent state where no requests	1110	Before the fork, IO::AIO enters a quiescent state where no requests
662	can be added in other threads and no results will be processed. After	1111	can be added in other threads and no results will be processed. After
663	the fork the parent simply leaves the quiescent state and continues	1112	the fork the parent simply leaves the quiescent state and continues
664	request/result processing, while the child clears the request/result	1113	request/result processing, while the child frees the request/result queue
665	queue (so the requests started before the fork will only be handled in	1114	(so that the requests started before the fork will only be handled in the
666	the parent). Threads will be started on demand until the limit ste in the	1115	parent). Threads will be started on demand until the limit set in the
667	parent process has been reached again.	1116	parent process has been reached again.
668		1117
669	In short: the parent will, after a short pause, continue as if fork had	1118	In short: the parent will, after a short pause, continue as if fork had
670	not been called, while the child will act as if IO::AIO has not been used	1119	not been called, while the child will act as if IO::AIO has not been used
671	yet.	1120	yet.
672		1121
		1122	=head2 MEMORY USAGE
		1123
		1124	Per-request usage:
		1125
		1126	Each aio request uses - depending on your architecture - around 100-200
		1127	bytes of memory. In addition, stat requests need a stat buffer (possibly
		1128	a few hundred bytes), readdir requires a result buffer and so on. Perl
		1129	scalars and other data passed into aio requests will also be locked and
		1130	will consume memory till the request has entered the done state.
		1131
		1132	This is now awfully much, so queuing lots of requests is not usually a
		1133	problem.
		1134
		1135	Per-thread usage:
		1136
		1137	In the execution phase, some aio requests require more memory for
		1138	temporary buffers, and each thread requires a stack and other data
		1139	structures (usually around 16k-128k, depending on the OS).
		1140
		1141	=head1 KNOWN BUGS
		1142
		1143	Known bugs will be fixed in the next release.
		1144
673	=head1 SEE ALSO	1145	=head1 SEE ALSO
674		1146
675	L<Coro>, L<Linux::AIO> (obsolete).	1147	L<Coro::AIO>.
676		1148
677	=head1 AUTHOR	1149	=head1 AUTHOR
678		1150
679	Marc Lehmann <schmorp@schmorp.de>	1151	Marc Lehmann <schmorp@schmorp.de>
680	http://home.schmorp.de/	1152	http://home.schmorp.de/

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.52 by root, Sat Oct 21 23:06:04 2006 UTC vs. Revision 1.87 by root, Sun Oct 29 00:52:02 2006 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.52 by root, Sat Oct 21 23:06:04 2006 UTC vs.
Revision 1.87 by root, Sun Oct 29 00:52:02 2006 UTC