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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.200 by root, Wed Jun 29 21:45:09 2011 UTC vs.
Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC

…		…
168	use common::sense;	168	use common::sense;
169		169
170	use base 'Exporter';	170	use base 'Exporter';
171		171
172	BEGIN {	172	BEGIN {
173	our $VERSION = '3.93';	173	our $VERSION = '4.0';
174		174
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
		179	aio_pathsync aio_readahead
179	aio_rename aio_link aio_move aio_copy aio_group	180	aio_rename aio_link aio_move aio_copy aio_group
180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181	aio_chmod aio_utime aio_truncate	182	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_mlock aio_mlockall	183	aio_msync aio_mtouch aio_mlock aio_mlockall
183	aio_statvfs);	184	aio_statvfs
		185	aio_wd);
184		186
185	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
186	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
187	min_parallel max_parallel max_idle idle_timeout	189	min_parallel max_parallel max_idle idle_timeout
188	nreqs nready npending nthreads	190	nreqs nready npending nthreads
…		…
204		206
205	This section simply lists the prototypes of the most important functions	207	This section simply lists the prototypes of the most important functions
206	for quick reference. See the following sections for function-by-function	208	for quick reference. See the following sections for function-by-function
207	documentation.	209	documentation.
208		210
		211	aio_wd $pathname, $callback->($wd)
209	aio_open $pathname, $flags, $mode, $callback->($fh)	212	aio_open $pathname, $flags, $mode, $callback->($fh)
210	aio_close $fh, $callback->($status)	213	aio_close $fh, $callback->($status)
211	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
…		…
218	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
220	aio_truncate $fh_or_path, $offset, $callback->($status)	223	aio_truncate $fh_or_path, $offset, $callback->($status)
221	aio_chmod $fh_or_path, $mode, $callback->($status)	224	aio_chmod $fh_or_path, $mode, $callback->($status)
222	aio_unlink $pathname, $callback->($status)	225	aio_unlink $pathname, $callback->($status)
223	aio_mknod $path, $mode, $dev, $callback->($status)	226	aio_mknod $pathname, $mode, $dev, $callback->($status)
224	aio_link $srcpath, $dstpath, $callback->($status)	227	aio_link $srcpath, $dstpath, $callback->($status)
225	aio_symlink $srcpath, $dstpath, $callback->($status)	228	aio_symlink $srcpath, $dstpath, $callback->($status)
226	aio_readlink $path, $callback->($link)	229	aio_readlink $pathname, $callback->($link)
		230	aio_realpath $pathname, $callback->($link)
227	aio_rename $srcpath, $dstpath, $callback->($status)	231	aio_rename $srcpath, $dstpath, $callback->($status)
228	aio_mkdir $pathname, $mode, $callback->($status)	232	aio_mkdir $pathname, $mode, $callback->($status)
229	aio_rmdir $pathname, $callback->($status)	233	aio_rmdir $pathname, $callback->($status)
230	aio_readdir $pathname, $callback->($entries)	234	aio_readdir $pathname, $callback->($entries)
231	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
234	aio_load $path, $data, $callback->($status)	238	aio_load $pathname, $data, $callback->($status)
235	aio_copy $srcpath, $dstpath, $callback->($status)	239	aio_copy $srcpath, $dstpath, $callback->($status)
236	aio_move $srcpath, $dstpath, $callback->($status)	240	aio_move $srcpath, $dstpath, $callback->($status)
237	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238	aio_rmtree $path, $callback->($status)	242	aio_rmtree $pathname, $callback->($status)
239	aio_sync $callback->($status)	243	aio_sync $callback->($status)
		244	aio_syncfs $fh, $callback->($status)
240	aio_fsync $fh, $callback->($status)	245	aio_fsync $fh, $callback->($status)
241	aio_fdatasync $fh, $callback->($status)	246	aio_fdatasync $fh, $callback->($status)
242	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243	aio_pathsync $path, $callback->($status)	248	aio_pathsync $pathname, $callback->($status)
244	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247	aio_mlockall $flags, $callback->($status)	252	aio_mlockall $flags, $callback->($status)
248	aio_group $callback->(...)	253	aio_group $callback->(...)
…		…
276	=head2 AIO REQUEST FUNCTIONS	281	=head2 AIO REQUEST FUNCTIONS
277		282
278	All the C<aio_*> calls are more or less thin wrappers around the syscall	283	All the C<aio_*> calls are more or less thin wrappers around the syscall
279	with the same name (sans C<aio_>). The arguments are similar or identical,	284	with the same name (sans C<aio_>). The arguments are similar or identical,
280	and they all accept an additional (and optional) C<$callback> argument	285	and they all accept an additional (and optional) C<$callback> argument
281	which must be a code reference. This code reference will get called with	286	which must be a code reference. This code reference will be called after
282	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	287	the syscall has been executed in an asynchronous fashion. The results
283	perl, which usually delivers "false") as its sole argument after the given	288	of the request will be passed as arguments to the callback (and, if an
284	syscall has been executed asynchronously.	289	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		290	most syscalls return C<-1> on error, unlike perl, which usually delivers
		291	"false").
		292
		293	Some requests (such as C<aio_readdir>) pass the actual results and
		294	communicate failures by passing C<undef>.
285		295
286	All functions expecting a filehandle keep a copy of the filehandle	296	All functions expecting a filehandle keep a copy of the filehandle
287	internally until the request has finished.	297	internally until the request has finished.
288		298
289	All functions return request objects of type L<IO::AIO::REQ> that allow	299	All functions return request objects of type L<IO::AIO::REQ> that allow
290	further manipulation of those requests while they are in-flight.	300	further manipulation of those requests while they are in-flight.
291		301
292	The pathnames you pass to these routines I<must> be absolute and	302	The pathnames you pass to these routines I<should> be absolute. The
293	encoded as octets. The reason for the former is that at the time the	303	reason for this is that at the time the request is being executed, the
294	request is being executed, the current working directory could have	304	current working directory could have changed. Alternatively, you can
295	changed. Alternatively, you can make sure that you never change the	305	make sure that you never change the current working directory anywhere
296	current working directory anywhere in the program and then use relative	306	in the program and then use relative paths. You can also take advantage
297	paths.	307	of IO::AIOs working directory abstraction, that lets you specify paths
		308	relative to some previously-opened "working directory object" - see the
		309	description of the C<IO::AIO::WD> class later in this document.
298		310
299	To encode pathnames as octets, either make sure you either: a) always pass	311	To encode pathnames as octets, either make sure you either: a) always pass
300	in filenames you got from outside (command line, readdir etc.) without	312	in filenames you got from outside (command line, readdir etc.) without
301	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	313	tinkering, b) are in your native filesystem encoding, c) use the Encode
302	your pathnames to the locale (or other) encoding in effect in the user	314	module and encode your pathnames to the locale (or other) encoding in
303	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	315	effect in the user environment, d) use Glib::filename_from_unicode on
304	use something else to ensure your scalar has the correct contents.	316	unicode filenames or e) use something else to ensure your scalar has the
		317	correct contents.
305		318
306	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	319	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
307	handles correctly whether it is set or not.	320	handles correctly whether it is set or not.
308		321
309	=over 4	322	=over 4
…		…
611		624
612	Asynchronously unlink (delete) a file and call the callback with the	625	Asynchronously unlink (delete) a file and call the callback with the
613	result code.	626	result code.
614		627
615		628
616	=item aio_mknod $path, $mode, $dev, $callback->($status)	629	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
617		630
618	[EXPERIMENTAL]	631	[EXPERIMENTAL]
619		632
620	Asynchronously create a device node (or fifo). See mknod(2).	633	Asynchronously create a device node (or fifo). See mknod(2).
621		634
622	The only (POSIX-) portable way of calling this function is:	635	The only (POSIX-) portable way of calling this function is:
623		636
624	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	637	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
625		638
626	See C<aio_stat> for info about some potentially helpful extra constants	639	See C<aio_stat> for info about some potentially helpful extra constants
627	and functions.	640	and functions.
628		641
629	=item aio_link $srcpath, $dstpath, $callback->($status)	642	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
636		649
637	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	650	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
638	the path C<$dstpath> and call the callback with the result code.	651	the path C<$dstpath> and call the callback with the result code.
639		652
640		653
641	=item aio_readlink $path, $callback->($link)	654	=item aio_readlink $pathname, $callback->($link)
642		655
643	Asynchronously read the symlink specified by C<$path> and pass it to	656	Asynchronously read the symlink specified by C<$path> and pass it to
644	the callback. If an error occurs, nothing or undef gets passed to the	657	the callback. If an error occurs, nothing or undef gets passed to the
645	callback.	658	callback.
646		659
647		660
		661	=item aio_realpath $pathname, $callback->($path)
		662
		663	Asynchronously make the path absolute and resolve any symlinks in
		664	C<$path>. The resulting path only consists of directories (Same as
		665	L<Cwd::realpath>).
		666
		667	This request can be used to get the absolute path of the current working
		668	directory by passing it a path of F<.> (a single dot).
		669
		670
648	=item aio_rename $srcpath, $dstpath, $callback->($status)	671	=item aio_rename $srcpath, $dstpath, $callback->($status)
649		672
650	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	673	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
651	rename(2) and call the callback with the result code.	674	rename(2) and call the callback with the result code.
652		675
…		…
674	array-ref with the filenames.	697	array-ref with the filenames.
675		698
676		699
677	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	700	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
678		701
679	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	702	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
680	behaviour and output format. In case of an error, C<$entries> will be	703	tune behaviour and output format. In case of an error, C<$entries> will be
681	C<undef>.	704	C<undef>.
682		705
683	The flags are a combination of the following constants, ORed together (the	706	The flags are a combination of the following constants, ORed together (the
684	flags will also be passed to the callback, possibly modified):	707	flags will also be passed to the callback, possibly modified):
685		708
…		…
732		755
733	=item IO::AIO::READDIR_FOUND_UNKNOWN	756	=item IO::AIO::READDIR_FOUND_UNKNOWN
734		757
735	This flag should not be set when calling C<aio_readdirx>. Instead, it	758	This flag should not be set when calling C<aio_readdirx>. Instead, it
736	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	759	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
737	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	760	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
738	C<$type>'s are known, which can be used to speed up some algorithms.	761	C<$type>'s are known, which can be used to speed up some algorithms.
739		762
740	=back	763	=back
741		764
742		765
743	=item aio_load $path, $data, $callback->($status)	766	=item aio_load $pathname, $data, $callback->($status)
744		767
745	This is a composite request that tries to fully load the given file into	768	This is a composite request that tries to fully load the given file into
746	memory. Status is the same as with aio_read.	769	memory. Status is the same as with aio_read.
747		770
748	=cut	771	=cut
…		…
883	};	906	};
884		907
885	$grp	908	$grp
886	}	909	}
887		910
888	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	911	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
889		912
890	Scans a directory (similar to C<aio_readdir>) but additionally tries to	913	Scans a directory (similar to C<aio_readdir>) but additionally tries to
891	efficiently separate the entries of directory C<$path> into two sets of	914	efficiently separate the entries of directory C<$path> into two sets of
892	names, directories you can recurse into (directories), and ones you cannot	915	names, directories you can recurse into (directories), and ones you cannot
893	recurse into (everything else, including symlinks to directories).	916	recurse into (everything else, including symlinks to directories).
…		…
924	Then entries will be sorted into likely directories a non-initial dot	947	Then entries will be sorted into likely directories a non-initial dot
925	currently) and likely non-directories (see C<aio_readdirx>). Then every	948	currently) and likely non-directories (see C<aio_readdirx>). Then every
926	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	949	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
927	in order of their inode numbers. If that succeeds, it assumes that the	950	in order of their inode numbers. If that succeeds, it assumes that the
928	entry is a directory or a symlink to directory (which will be checked	951	entry is a directory or a symlink to directory (which will be checked
929	seperately). This is often faster than stat'ing the entry itself because	952	separately). This is often faster than stat'ing the entry itself because
930	filesystems might detect the type of the entry without reading the inode	953	filesystems might detect the type of the entry without reading the inode
931	data (e.g. ext2fs filetype feature), even on systems that cannot return	954	data (e.g. ext2fs filetype feature), even on systems that cannot return
932	the filetype information on readdir.	955	the filetype information on readdir.
933		956
934	If the known number of directories (link count - 2) has been reached, the	957	If the known number of directories (link count - 2) has been reached, the
…		…
950		973
951	my $grp = aio_group $cb;	974	my $grp = aio_group $cb;
952		975
953	$maxreq = 4 if $maxreq <= 0;	976	$maxreq = 4 if $maxreq <= 0;
954		977
955	# stat once	978	# get a wd object
956	aioreq_pri $pri;	979	aioreq_pri $pri;
957	add $grp aio_stat $path, sub {	980	add $grp aio_wd $path, sub {
		981	$_[0]
958	return $grp->result () if $_[0];	982	or return $grp->result ();
959	my $now = time;
960	my $hash1 = join ":", (stat _)[0,1,3,7,9];
961		983
962	# read the directory entries	984	my $wd = [shift, "."];
		985
		986	# stat once
963	aioreq_pri $pri;	987	aioreq_pri $pri;
964	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	988	add $grp aio_stat $wd, sub {
965	my $entries = shift
966	or return $grp->result ();	989	return $grp->result () if $_[0];
		990	my $now = time;
		991	my $hash1 = join ":", (stat _)[0,1,3,7,9];
967		992
968	# stat the dir another time	993	# read the directory entries
969	aioreq_pri $pri;	994	aioreq_pri $pri;
		995	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		996	my $entries = shift
		997	or return $grp->result ();
		998
		999	# stat the dir another time
		1000	aioreq_pri $pri;
970	add $grp aio_stat $path, sub {	1001	add $grp aio_stat $wd, sub {
971	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1002	my $hash2 = join ":", (stat _)[0,1,3,7,9];
972		1003
973	my $ndirs;	1004	my $ndirs;
974		1005
975	# take the slow route if anything looks fishy	1006	# take the slow route if anything looks fishy
976	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1007	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
977	$ndirs = -1;	1008	$ndirs = -1;
978	} else {	1009	} else {
979	# if nlink == 2, we are finished	1010	# if nlink == 2, we are finished
980	# for non-posix-fs's, we rely on nlink < 2	1011	# for non-posix-fs's, we rely on nlink < 2
981	$ndirs = (stat _)[3] - 2	1012	$ndirs = (stat _)[3] - 2
982	or return $grp->result ([], $entries);	1013	or return $grp->result ([], $entries);
983	}	1014	}
984		1015
985	my (@dirs, @nondirs);	1016	my (@dirs, @nondirs);
986		1017
987	my $statgrp = add $grp aio_group sub {	1018	my $statgrp = add $grp aio_group sub {
988	$grp->result (\@dirs, \@nondirs);	1019	$grp->result (\@dirs, \@nondirs);
989	};	1020	};
990		1021
991	limit $statgrp $maxreq;	1022	limit $statgrp $maxreq;
992	feed $statgrp sub {	1023	feed $statgrp sub {
993	return unless @$entries;	1024	return unless @$entries;
994	my $entry = shift @$entries;	1025	my $entry = shift @$entries;
995		1026
996	aioreq_pri $pri;	1027	aioreq_pri $pri;
		1028	$wd->[1] = "$entry/.";
997	add $statgrp aio_stat "$path/$entry/.", sub {	1029	add $statgrp aio_stat $wd, sub {
998	if ($_[0] < 0) {	1030	if ($_[0] < 0) {
999	push @nondirs, $entry;	1031	push @nondirs, $entry;
1000	} else {	1032	} else {
1001	# need to check for real directory	1033	# need to check for real directory
1002	aioreq_pri $pri;	1034	aioreq_pri $pri;
		1035	$wd->[1] = $entry;
1003	add $statgrp aio_lstat "$path/$entry", sub {	1036	add $statgrp aio_lstat $wd, sub {
1004	if (-d _) {	1037	if (-d _) {
1005	push @dirs, $entry;	1038	push @dirs, $entry;
1006		1039
1007	unless (--$ndirs) {	1040	unless (--$ndirs) {
1008	push @nondirs, @$entries;	1041	push @nondirs, @$entries;
1009	feed $statgrp;	1042	feed $statgrp;
		1043	}
		1044	} else {
		1045	push @nondirs, $entry;
1010	}	1046	}
1011	} else {
1012	push @nondirs, $entry;
1013	}	1047	}
1014	}	1048	}
1015	}	1049	};
1016	};	1050	};
1017	};	1051	};
1018	};	1052	};
1019	};	1053	};
1020	};	1054	};
1021		1055
1022	$grp	1056	$grp
1023	}	1057	}
1024		1058
1025	=item aio_rmtree $path, $callback->($status)	1059	=item aio_rmtree $pathname, $callback->($status)
1026		1060
1027	Delete a directory tree starting (and including) C<$path>, return the	1061	Delete a directory tree starting (and including) C<$path>, return the
1028	status of the final C<rmdir> only. This is a composite request that	1062	status of the final C<rmdir> only. This is a composite request that
1029	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1063	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1030	everything else.	1064	everything else.
…		…
1072	callback with the fdatasync result code.	1106	callback with the fdatasync result code.
1073		1107
1074	If this call isn't available because your OS lacks it or it couldn't be	1108	If this call isn't available because your OS lacks it or it couldn't be
1075	detected, it will be emulated by calling C<fsync> instead.	1109	detected, it will be emulated by calling C<fsync> instead.
1076		1110
		1111	=item aio_syncfs $fh, $callback->($status)
		1112
		1113	Asynchronously call the syncfs syscall to sync the filesystem associated
		1114	to the given filehandle and call the callback with the syncfs result
		1115	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1116	errno to C<ENOSYS> nevertheless.
		1117
1077	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1118	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1078		1119
1079	Sync the data portion of the file specified by C<$offset> and C<$length>	1120	Sync the data portion of the file specified by C<$offset> and C<$length>
1080	to disk (but NOT the metadata), by calling the Linux-specific	1121	to disk (but NOT the metadata), by calling the Linux-specific
1081	sync_file_range call. If sync_file_range is not available or it returns	1122	sync_file_range call. If sync_file_range is not available or it returns
…		…
1084	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1125	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1085	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1126	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1086	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1127	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1087	manpage for details.	1128	manpage for details.
1088		1129
1089	=item aio_pathsync $path, $callback->($status)	1130	=item aio_pathsync $pathname, $callback->($status)
1090		1131
1091	This request tries to open, fsync and close the given path. This is a	1132	This request tries to open, fsync and close the given path. This is a
1092	composite request intended to sync directories after directory operations	1133	composite request intended to sync directories after directory operations
1093	(E.g. rename). This might not work on all operating systems or have any	1134	(E.g. rename). This might not work on all operating systems or have any
1094	specific effect, but usually it makes sure that directory changes get	1135	specific effect, but usually it makes sure that directory changes get
…		…
1237	immense (it blocks a thread for a long time) so do not use this function	1278	immense (it blocks a thread for a long time) so do not use this function
1238	except to put your application under artificial I/O pressure.	1279	except to put your application under artificial I/O pressure.
1239		1280
1240	=back	1281	=back
1241		1282
		1283
		1284	=head2 IO::AIO::WD - multiple working directories
		1285
		1286	Your process only has one current working directory, which is used by all
		1287	threads. This makes it hard to use relative paths (some other component
		1288	could call C<chdir> at any time, and it is hard to control when the path
		1289	will be used by IO::AIO).
		1290
		1291	One solution for this is to always use absolute paths. This usually works,
		1292	but can be quite slow (the kernel has to walk the whole path on every
		1293	access), and can also be a hassle to implement.
		1294
		1295	Newer POSIX systems have a number of functions (openat, fdopendir,
		1296	futimensat and so on) that make it possible to specify working directories
		1297	per operation.
		1298
		1299	For portability, and because the clowns who "designed", or shall I write,
		1300	perpetrated this new interface were obviously half-drunk, this abstraction
		1301	cannot be perfect, though.
		1302
		1303	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1304	object. This object stores the canonicalised, absolute version of the
		1305	path, and on systems that allow it, also a directory file descriptor.
		1306
		1307	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1308	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1309	object and a pathname instead. If the pathname is absolute, the
		1310	IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative
		1311	to that IO::AIO::WD object.
		1312
		1313	For example, to get a wd object for F</etc> and then stat F<passwd>
		1314	inside, you would write:
		1315
		1316	aio_wd "/etc", sub {
		1317	my $etcdir = shift;
		1318
		1319	# although $etcdir can be undef on error, there is generally no reason
		1320	# to check for errors here, as aio_stat will fail with ENOENT
		1321	# when $etcdir is undef.
		1322
		1323	aio_stat [$etcdir, "passwd"], sub {
		1324	# yay
		1325	};
		1326	};
		1327
		1328	This shows that creating an IO::AIO::WD object is itself a potentially
		1329	blocking operation, which is why it is done asynchronously.
		1330
		1331	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1332	object and the pathname string, so you could write the following without
		1333	causing any issues due to C<$path> getting reused:
		1334
		1335	my $path = [$wd, undef];
		1336
		1337	for my $name (qw(abc def ghi)) {
		1338	$path->[1] = $name;
		1339	aio_stat $path, sub {
		1340	# ...
		1341	};
		1342	}
		1343
		1344	There are some caveats: when directories get renamed (or deleted), the
		1345	pathname string doesn't change, so will point to the new directory (or
		1346	nowhere at all), while the directory fd, if available on the system,
		1347	will still point to the original directory. Most functions accepting a
		1348	pathname will use the directory fd on newer systems, and the string on
		1349	older systems. Some functions (such as realpath) will always rely on the
		1350	string form of the pathname.
		1351
		1352	So this fucntionality is mainly useful to get some protection against
		1353	C<chdir>, to easily get an absolute path out of a relative path for future
		1354	reference, and to speed up doing many operations in the same directory
		1355	(e.g. when stat'ing all files in a directory).
		1356
		1357	The following functions implement this working directory abstraction:
		1358
		1359	=over 4
		1360
		1361	=item aio_wd $pathname, $callback->($wd)
		1362
		1363	Asynchonously canonicalise the given pathname and convert it to an
		1364	IO::AIO::WD object representing it. If possible and supported on the
		1365	system, also open a directory fd to speed up pathname resolution relative
		1366	to this working directory.
		1367
		1368	If something goes wrong, then C<undef> is passwd to the callback instead
		1369	of a working directory object and C<$!> is set appropriately. Since
		1370	passing C<undef> as working directory component of a pathname fails the
		1371	request with C<ENOENT>, there is often no need for error checking in the
		1372	C<aio_wd> callback, as future requests using the value will fail in the
		1373	expected way.
		1374
		1375	If this call isn't available because your OS lacks it or it couldn't be
		1376	detected, it will be emulated by calling C<fsync> instead.
		1377
		1378	=item IO::AIO::CWD
		1379
		1380	This is a compiletime constant (object) that represents the process
		1381	current working directory.
		1382
		1383	Specifying this object as working directory object for a pathname is as
		1384	if the pathname would be specified directly, without a directory object,
		1385	e.g., these calls are functionally identical:
		1386
		1387	aio_stat "somefile", sub { ... };
		1388	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1389
		1390	=back
		1391
		1392
1242	=head2 IO::AIO::REQ CLASS	1393	=head2 IO::AIO::REQ CLASS
1243		1394
1244	All non-aggregate C<aio_*> functions return an object of this class when	1395	All non-aggregate C<aio_*> functions return an object of this class when
1245	called in non-void context.	1396	called in non-void context.
1246		1397
…		…
1363		1514
1364	Sets a feeder/generator on this group: every group can have an attached	1515	Sets a feeder/generator on this group: every group can have an attached
1365	generator that generates requests if idle. The idea behind this is that,	1516	generator that generates requests if idle. The idea behind this is that,
1366	although you could just queue as many requests as you want in a group,	1517	although you could just queue as many requests as you want in a group,
1367	this might starve other requests for a potentially long time. For example,	1518	this might starve other requests for a potentially long time. For example,
1368	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1519	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1369	delaying any later requests for a long time.	1520	requests, delaying any later requests for a long time.
1370		1521
1371	To avoid this, and allow incremental generation of requests, you can	1522	To avoid this, and allow incremental generation of requests, you can
1372	instead a group and set a feeder on it that generates those requests. The	1523	instead a group and set a feeder on it that generates those requests. The
1373	feed callback will be called whenever there are few enough (see C<limit>,	1524	feed callback will be called whenever there are few enough (see C<limit>,
1374	below) requests active in the group itself and is expected to queue more	1525	below) requests active in the group itself and is expected to queue more
…		…
1653		1804
1654	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1805	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1655		1806
1656	Simply calls the C<posix_fadvise> function (see its	1807	Simply calls the C<posix_fadvise> function (see its
1657	manpage for details). The following advice constants are	1808	manpage for details). The following advice constants are
1658	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1809	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1659	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1810	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1660	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	1811	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1661		1812
1662	On systems that do not implement C<posix_fadvise>, this function returns	1813	On systems that do not implement C<posix_fadvise>, this function returns
1663	ENOSYS, otherwise the return value of C<posix_fadvise>.	1814	ENOSYS, otherwise the return value of C<posix_fadvise>.
1664		1815
1665	=item IO::AIO::madvise $scalar, $offset, $len, $advice	1816	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1666		1817
1667	Simply calls the C<posix_madvise> function (see its	1818	Simply calls the C<posix_madvise> function (see its
1668	manpage for details). The following advice constants are	1819	manpage for details). The following advice constants are
1669	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	1820	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1670	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	1821	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1671		1822
1672	On systems that do not implement C<posix_madvise>, this function returns	1823	On systems that do not implement C<posix_madvise>, this function returns
1673	ENOSYS, otherwise the return value of C<posix_madvise>.	1824	ENOSYS, otherwise the return value of C<posix_madvise>.
1674		1825
1675	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	1826	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1676		1827
1677	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	1828	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1678	$scalar (see its manpage for details). The following protect	1829	$scalar (see its manpage for details). The following protect
1679	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	1830	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1680	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	1831	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1681		1832
1682	On systems that do not implement C<mprotect>, this function returns	1833	On systems that do not implement C<mprotect>, this function returns
1683	ENOSYS, otherwise the return value of C<mprotect>.	1834	ENOSYS, otherwise the return value of C<mprotect>.
1684		1835
…		…
1792	=head2 FORK BEHAVIOUR	1943	=head2 FORK BEHAVIOUR
1793		1944
1794	Usage of pthreads in a program changes the semantics of fork	1945	Usage of pthreads in a program changes the semantics of fork
1795	considerably. Specifically, only async-safe functions can be called after	1946	considerably. Specifically, only async-safe functions can be called after
1796	fork. Perl doesn't know about this, so in general, you cannot call fork	1947	fork. Perl doesn't know about this, so in general, you cannot call fork
1797	with defined behaviour in perl. IO::AIO uses pthreads, so this applies,	1948	with defined behaviour in perl if pthreads are involved. IO::AIO uses
1798	but many other extensions and (for inexplicable reasons) perl itself often	1949	pthreads, so this applies, but many other extensions and (for inexplicable
1799	is linked against pthreads, so this limitation applies.	1950	reasons) perl itself often is linked against pthreads, so this limitation
		1951	applies to quite a lot of perls.
1800		1952
1801	Some operating systems have extensions that allow safe use of fork, and	1953	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1802	this module should do "the right thing" on those, and tries on others. At	1954	only works in the process that loaded it. Forking is fully supported, but
1803	the time of this writing (2011) only GNU/Linux supports these extensions	1955	using IO::AIO in the child is not.
1804	to POSIX.	1956
		1957	You might get around by not I<using> IO::AIO before (or after)
		1958	forking. You could also try to call the L<IO::AIO::reinit> function in the
		1959	child:
		1960
		1961	=over 4
		1962
		1963	=item IO::AIO::reinit
		1964
		1965	Abandons all current requests and I/O threads and simply reinitialises all
		1966	data structures. This is not an operation supported by any standards, but
		1967	happens to work on GNU/Linux and some newer BSD systems.
		1968
		1969	The only reasonable use for this function is to call it after forking, if
		1970	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1971	the process will result in undefined behaviour. Calling it at any time
		1972	will also result in any undefined (by POSIX) behaviour.
		1973
		1974	=back
1805		1975
1806	=head2 MEMORY USAGE	1976	=head2 MEMORY USAGE
1807		1977
1808	Per-request usage:	1978	Per-request usage:
1809		1979

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.200 by root, Wed Jun 29 21:45:09 2011 UTC vs. Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.200 by root, Wed Jun 29 21:45:09 2011 UTC vs.
Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC