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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.198 by root, Wed Jun 29 11:25:17 2011 UTC vs.
Revision 1.211 by root, Tue Sep 27 12:10:29 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 = '3.91';	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->(...)
…		…
287	internally until the request has finished.	292	internally until the request has finished.
288		293
289	All functions return request objects of type L<IO::AIO::REQ> that allow	294	All functions return request objects of type L<IO::AIO::REQ> that allow
290	further manipulation of those requests while they are in-flight.	295	further manipulation of those requests while they are in-flight.
291		296
292	The pathnames you pass to these routines I<must> be absolute and	297	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	298	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	299	current working directory could have changed. Alternatively, you can make
295	changed. Alternatively, you can make sure that you never change the	300	sure that you never change the current working directory anywhere in
296	current working directory anywhere in the program and then use relative	301	the program and then use relative paths. Lastly, you can take advantage
297	paths.	302	of IO::AIOs working directory abstraction - see the description of the
		303	C<IO::AIO::WD> class later in this document.
298		304
299	To encode pathnames as octets, either make sure you either: a) always pass	305	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	306	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	307	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
302	your pathnames to the locale (or other) encoding in effect in the user	308	your pathnames to the locale (or other) encoding in effect in the user
…		…
611		617
612	Asynchronously unlink (delete) a file and call the callback with the	618	Asynchronously unlink (delete) a file and call the callback with the
613	result code.	619	result code.
614		620
615		621
616	=item aio_mknod $path, $mode, $dev, $callback->($status)	622	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
617		623
618	[EXPERIMENTAL]	624	[EXPERIMENTAL]
619		625
620	Asynchronously create a device node (or fifo). See mknod(2).	626	Asynchronously create a device node (or fifo). See mknod(2).
621		627
622	The only (POSIX-) portable way of calling this function is:	628	The only (POSIX-) portable way of calling this function is:
623		629
624	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	630	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
625		631
626	See C<aio_stat> for info about some potentially helpful extra constants	632	See C<aio_stat> for info about some potentially helpful extra constants
627	and functions.	633	and functions.
628		634
629	=item aio_link $srcpath, $dstpath, $callback->($status)	635	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
636		642
637	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	643	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
638	the path C<$dstpath> and call the callback with the result code.	644	the path C<$dstpath> and call the callback with the result code.
639		645
640		646
641	=item aio_readlink $path, $callback->($link)	647	=item aio_readlink $pathname, $callback->($link)
642		648
643	Asynchronously read the symlink specified by C<$path> and pass it to	649	Asynchronously read the symlink specified by C<$path> and pass it to
644	the callback. If an error occurs, nothing or undef gets passed to the	650	the callback. If an error occurs, nothing or undef gets passed to the
645	callback.	651	callback.
646		652
647		653
		654	=item aio_realpath $pathname, $callback->($path)
		655
		656	Asynchronously make the path absolute and resolve any symlinks in
		657	C<$path>. The resulting path only consists of directories (Same as
		658	L<Cwd::realpath>).
		659
		660	This request can be used to get the absolute path of the current working
		661	directory by passing it a path of F<.> (a single dot).
		662
		663
648	=item aio_rename $srcpath, $dstpath, $callback->($status)	664	=item aio_rename $srcpath, $dstpath, $callback->($status)
649		665
650	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	666	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
651	rename(2) and call the callback with the result code.	667	rename(2) and call the callback with the result code.
652		668
…		…
674	array-ref with the filenames.	690	array-ref with the filenames.
675		691
676		692
677	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	693	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
678		694
679	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	695	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	696	tune behaviour and output format. In case of an error, C<$entries> will be
681	C<undef>.	697	C<undef>.
682		698
683	The flags are a combination of the following constants, ORed together (the	699	The flags are a combination of the following constants, ORed together (the
684	flags will also be passed to the callback, possibly modified):	700	flags will also be passed to the callback, possibly modified):
685		701
…		…
732		748
733	=item IO::AIO::READDIR_FOUND_UNKNOWN	749	=item IO::AIO::READDIR_FOUND_UNKNOWN
734		750
735	This flag should not be set when calling C<aio_readdirx>. Instead, it	751	This flag should not be set when calling C<aio_readdirx>. Instead, it
736	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	752	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
737	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	753	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
738	C<$type>'s are known, which can be used to speed up some algorithms.	754	C<$type>'s are known, which can be used to speed up some algorithms.
739		755
740	=back	756	=back
741		757
742		758
743	=item aio_load $path, $data, $callback->($status)	759	=item aio_load $pathname, $data, $callback->($status)
744		760
745	This is a composite request that tries to fully load the given file into	761	This is a composite request that tries to fully load the given file into
746	memory. Status is the same as with aio_read.	762	memory. Status is the same as with aio_read.
747		763
748	=cut	764	=cut
…		…
883	};	899	};
884		900
885	$grp	901	$grp
886	}	902	}
887		903
888	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	904	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
889		905
890	Scans a directory (similar to C<aio_readdir>) but additionally tries to	906	Scans a directory (similar to C<aio_readdir>) but additionally tries to
891	efficiently separate the entries of directory C<$path> into two sets of	907	efficiently separate the entries of directory C<$path> into two sets of
892	names, directories you can recurse into (directories), and ones you cannot	908	names, directories you can recurse into (directories), and ones you cannot
893	recurse into (everything else, including symlinks to directories).	909	recurse into (everything else, including symlinks to directories).
…		…
924	Then entries will be sorted into likely directories a non-initial dot	940	Then entries will be sorted into likely directories a non-initial dot
925	currently) and likely non-directories (see C<aio_readdirx>). Then every	941	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,	942	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	943	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	944	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	945	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	946	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	947	data (e.g. ext2fs filetype feature), even on systems that cannot return
932	the filetype information on readdir.	948	the filetype information on readdir.
933		949
934	If the known number of directories (link count - 2) has been reached, the	950	If the known number of directories (link count - 2) has been reached, the
…		…
950		966
951	my $grp = aio_group $cb;	967	my $grp = aio_group $cb;
952		968
953	$maxreq = 4 if $maxreq <= 0;	969	$maxreq = 4 if $maxreq <= 0;
954		970
955	# stat once	971	# get a wd object
		972
956	aioreq_pri $pri;	973	aioreq_pri $pri;
957	add $grp aio_stat $path, sub {	974	add $grp aio_wd $path, sub {
958	return $grp->result () if $_[0];	975	my $wd = [shift, "."];
959	my $now = time;
960	my $hash1 = join ":", (stat _)[0,1,3,7,9];
961		976
962	# read the directory entries	977	# stat once
963	aioreq_pri $pri;	978	aioreq_pri $pri;
964	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	979	add $grp aio_stat $wd, sub {
965	my $entries = shift
966	or return $grp->result ();	980	return $grp->result () if $_[0];
		981	my $now = time;
		982	my $hash1 = join ":", (stat _)[0,1,3,7,9];
967		983
968	# stat the dir another time	984	# read the directory entries
969	aioreq_pri $pri;	985	aioreq_pri $pri;
		986	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		987	my $entries = shift
		988	or return $grp->result ();
		989
		990	# stat the dir another time
		991	aioreq_pri $pri;
970	add $grp aio_stat $path, sub {	992	add $grp aio_stat $wd, sub {
971	my $hash2 = join ":", (stat _)[0,1,3,7,9];	993	my $hash2 = join ":", (stat _)[0,1,3,7,9];
972		994
973	my $ndirs;	995	my $ndirs;
974		996
975	# take the slow route if anything looks fishy	997	# take the slow route if anything looks fishy
976	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	998	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
977	$ndirs = -1;	999	$ndirs = -1;
978	} else {	1000	} else {
979	# if nlink == 2, we are finished	1001	# if nlink == 2, we are finished
980	# for non-posix-fs's, we rely on nlink < 2	1002	# for non-posix-fs's, we rely on nlink < 2
981	$ndirs = (stat _)[3] - 2	1003	$ndirs = (stat _)[3] - 2
982	or return $grp->result ([], $entries);	1004	or return $grp->result ([], $entries);
983	}	1005	}
984		1006
985	my (@dirs, @nondirs);	1007	my (@dirs, @nondirs);
986		1008
987	my $statgrp = add $grp aio_group sub {	1009	my $statgrp = add $grp aio_group sub {
988	$grp->result (\@dirs, \@nondirs);	1010	$grp->result (\@dirs, \@nondirs);
989	};	1011	};
990		1012
991	limit $statgrp $maxreq;	1013	limit $statgrp $maxreq;
992	feed $statgrp sub {	1014	feed $statgrp sub {
993	return unless @$entries;	1015	return unless @$entries;
994	my $entry = shift @$entries;	1016	my $entry = shift @$entries;
995		1017
996	aioreq_pri $pri;	1018	aioreq_pri $pri;
		1019	$wd->[1] = "$entry/.";
997	add $statgrp aio_stat "$path/$entry/.", sub {	1020	add $statgrp aio_stat $wd, sub {
998	if ($_[0] < 0) {	1021	if ($_[0] < 0) {
999	push @nondirs, $entry;	1022	push @nondirs, $entry;
1000	} else {	1023	} else {
1001	# need to check for real directory	1024	# need to check for real directory
1002	aioreq_pri $pri;	1025	aioreq_pri $pri;
		1026	$wd->[1] = $entry;
1003	add $statgrp aio_lstat "$path/$entry", sub {	1027	add $statgrp aio_lstat $wd, sub {
1004	if (-d _) {	1028	if (-d _) {
1005	push @dirs, $entry;	1029	push @dirs, $entry;
1006		1030
1007	unless (--$ndirs) {	1031	unless (--$ndirs) {
1008	push @nondirs, @$entries;	1032	push @nondirs, @$entries;
1009	feed $statgrp;	1033	feed $statgrp;
		1034	}
		1035	} else {
		1036	push @nondirs, $entry;
1010	}	1037	}
1011	} else {
1012	push @nondirs, $entry;
1013	}	1038	}
1014	}	1039	}
1015	}	1040	};
1016	};	1041	};
1017	};	1042	};
1018	};	1043	};
1019	};	1044	};
1020	};	1045	};
1021		1046
1022	$grp	1047	$grp
1023	}	1048	}
1024		1049
1025	=item aio_rmtree $path, $callback->($status)	1050	=item aio_rmtree $pathname, $callback->($status)
1026		1051
1027	Delete a directory tree starting (and including) C<$path>, return the	1052	Delete a directory tree starting (and including) C<$path>, return the
1028	status of the final C<rmdir> only. This is a composite request that	1053	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	1054	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1030	everything else.	1055	everything else.
…		…
1072	callback with the fdatasync result code.	1097	callback with the fdatasync result code.
1073		1098
1074	If this call isn't available because your OS lacks it or it couldn't be	1099	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.	1100	detected, it will be emulated by calling C<fsync> instead.
1076		1101
		1102	=item aio_syncfs $fh, $callback->($status)
		1103
		1104	Asynchronously call the syncfs syscall to sync the filesystem associated
		1105	to the given filehandle and call the callback with the syncfs result
		1106	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1107	errno to C<ENOSYS> nevertheless.
		1108
1077	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1109	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1078		1110
1079	Sync the data portion of the file specified by C<$offset> and C<$length>	1111	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	1112	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	1113	sync_file_range call. If sync_file_range is not available or it returns
…		…
1084	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1116	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1085	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1117	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1086	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1118	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1087	manpage for details.	1119	manpage for details.
1088		1120
1089	=item aio_pathsync $path, $callback->($status)	1121	=item aio_pathsync $pathname, $callback->($status)
1090		1122
1091	This request tries to open, fsync and close the given path. This is a	1123	This request tries to open, fsync and close the given path. This is a
1092	composite request intended to sync directories after directory operations	1124	composite request intended to sync directories after directory operations
1093	(E.g. rename). This might not work on all operating systems or have any	1125	(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	1126	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	1269	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.	1270	except to put your application under artificial I/O pressure.
1239		1271
1240	=back	1272	=back
1241		1273
		1274
		1275	=head2 IO::AIO::WD - multiple working directories
		1276
		1277	Your process only has one current working directory, which is used by all
		1278	threads. This makes it hard to use relative paths (some other component
		1279	could call C<chdir> at any time, and it is hard to control when the path
		1280	will be used by IO::AIO).
		1281
		1282	One solution for this is to always use absolute paths. This usually works,
		1283	but can be quite slow (the kernel has to walk the whole path on every
		1284	access), and can also be a hassle to implement.
		1285
		1286	Newer POSIX systems have a number of functions (openat, fdopendir,
		1287	futimensat and so on) that make it possible to specify working directories
		1288	per operation.
		1289
		1290	For portability, and because the clowns who "designed", or shall I write,
		1291	perpetrated this new interface were obviously half-drunk, this abstraction
		1292	cannot be perfect, though.
		1293
		1294	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1295	object. This object stores the canonicalised, absolute version of the
		1296	path, and on systems that allow it, also a directory file descriptor.
		1297
		1298	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1299	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1300	object and a pathname instead. If the pathname is absolute, the
		1301	IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative
		1302	to that IO::AIO::WD object.
		1303
		1304	For example, to get a wd object for F</etc> and then stat F<passwd>
		1305	inside, you would write:
		1306
		1307	aio_wd "/etc", sub {
		1308	my $etcdir = shift;
		1309
		1310	# although $etcdir can be undef on error, there is generally no reason
		1311	# to check for errors here, as aio_stat will fail with ENOENT
		1312	# when $etcdir is undef.
		1313
		1314	aio_stat [$etcdir, "passwd"], sub {
		1315	# yay
		1316	};
		1317	};
		1318
		1319	This shows that creating an IO::AIO::WD object is itself a potentially
		1320	blocking operation, which is why it is done asynchronously.
		1321
		1322	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1323	object and the pathname string, so you could write the following without
		1324	causing any issues due to C<$path> getting reused:
		1325
		1326	my $path = [$wd, undef];
		1327
		1328	for my $name (qw(abc def ghi)) {
		1329	$path->[1] = $name;
		1330	aio_stat $path, sub {
		1331	# ...
		1332	};
		1333	}
		1334
		1335	There are some caveats: when directories get renamed (or deleted), the
		1336	pathname string doesn't change, so will point to the new directory (or
		1337	nowhere at all), while the directory fd, if available on the system,
		1338	will still point to the original directory. Most functions accepting a
		1339	pathname will use the directory fd on newer systems, and the string on
		1340	older systems. Some functions (such as realpath) will always rely on the
		1341	string form of the pathname.
		1342
		1343	So this fucntionality is mainly useful to get some protection against
		1344	C<chdir>, to easily get an absolute path out of a relative path for future
		1345	reference, and to speed up doing many operations in the same directory
		1346	(e.g. when stat'ing all files in a directory).
		1347
		1348	The following functions implement this working directory abstraction:
		1349
		1350	=over 4
		1351
		1352	=item aio_wd $pathname, $callback->($wd)
		1353
		1354	Asynchonously canonicalise the given pathname and convert it to an
		1355	IO::AIO::WD object representing it. If possible and supported on the
		1356	system, also open a directory fd to speed up pathname resolution relative
		1357	to this working directory.
		1358
		1359	If something goes wrong, then C<undef> is passwd to the callback instead
		1360	of a working directory object and C<$!> is set appropriately. Since
		1361	passing C<undef> as working directory component of a pathname fails the
		1362	request with C<ENOENT>, there is often no need for error checking in the
		1363	C<aio_wd> callback, as future requests using the value will fail in the
		1364	expected way.
		1365
		1366	If this call isn't available because your OS lacks it or it couldn't be
		1367	detected, it will be emulated by calling C<fsync> instead.
		1368
		1369	=item IO::AIO::CWD
		1370
		1371	This is a compiletime constant (object) that represents the process
		1372	current working directory.
		1373
		1374	Specifying this object as working directory object for a pathname is as
		1375	if the pathname would be specified directly, without a directory object,
		1376	e.g., these calls are functionally identical:
		1377
		1378	aio_stat "somefile", sub { ... };
		1379	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1380
		1381	=back
		1382
		1383
1242	=head2 IO::AIO::REQ CLASS	1384	=head2 IO::AIO::REQ CLASS
1243		1385
1244	All non-aggregate C<aio_*> functions return an object of this class when	1386	All non-aggregate C<aio_*> functions return an object of this class when
1245	called in non-void context.	1387	called in non-void context.
1246		1388
…		…
1363		1505
1364	Sets a feeder/generator on this group: every group can have an attached	1506	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,	1507	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,	1508	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,	1509	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,	1510	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1369	delaying any later requests for a long time.	1511	requests, delaying any later requests for a long time.
1370		1512
1371	To avoid this, and allow incremental generation of requests, you can	1513	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	1514	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>,	1515	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	1516	below) requests active in the group itself and is expected to queue more
…		…
1653		1795
1654	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1796	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1655		1797
1656	Simply calls the C<posix_fadvise> function (see its	1798	Simply calls the C<posix_fadvise> function (see its
1657	manpage for details). The following advice constants are	1799	manpage for details). The following advice constants are
1658	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1800	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1659	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1801	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1660	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	1802	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1661		1803
1662	On systems that do not implement C<posix_fadvise>, this function returns	1804	On systems that do not implement C<posix_fadvise>, this function returns
1663	ENOSYS, otherwise the return value of C<posix_fadvise>.	1805	ENOSYS, otherwise the return value of C<posix_fadvise>.
1664		1806
1665	=item IO::AIO::madvise $scalar, $offset, $len, $advice	1807	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1666		1808
1667	Simply calls the C<posix_madvise> function (see its	1809	Simply calls the C<posix_madvise> function (see its
1668	manpage for details). The following advice constants are	1810	manpage for details). The following advice constants are
1669	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	1811	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>.	1812	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1671		1813
1672	On systems that do not implement C<posix_madvise>, this function returns	1814	On systems that do not implement C<posix_madvise>, this function returns
1673	ENOSYS, otherwise the return value of C<posix_madvise>.	1815	ENOSYS, otherwise the return value of C<posix_madvise>.
1674		1816
1675	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	1817	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1676		1818
1677	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	1819	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1678	$scalar (see its manpage for details). The following protect	1820	$scalar (see its manpage for details). The following protect
1679	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	1821	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1680	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	1822	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1681		1823
1682	On systems that do not implement C<mprotect>, this function returns	1824	On systems that do not implement C<mprotect>, this function returns
1683	ENOSYS, otherwise the return value of C<mprotect>.	1825	ENOSYS, otherwise the return value of C<mprotect>.
1684		1826
…		…
1792	=head2 FORK BEHAVIOUR	1934	=head2 FORK BEHAVIOUR
1793		1935
1794	Usage of pthreads in a program changes the semantics of fork	1936	Usage of pthreads in a program changes the semantics of fork
1795	considerably. Specifically, only async-safe functions can be called after	1937	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	1938	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,	1939	with defined behaviour in perl if pthreads are involved. IO::AIO uses
1798	but many other extensions and (for inexplicable reasons) perl itself often	1940	pthreads, so this applies, but many other extensions and (for inexplicable
1799	is linked against pthreads, so this limitation applies.	1941	reasons) perl itself often is linked against pthreads, so this limitation
		1942	applies to quite a lot of perls.
1800		1943
1801	Some operating systems have extensions that allow safe use of fork, and	1944	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	1945	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	1946	using IO::AIO in the child is not.
1804	to POSIX.	1947
		1948	You might get around by not I<using> IO::AIO before (or after)
		1949	forking. You could also try to call the L<IO::AIO::reinit> function in the
		1950	child:
		1951
		1952	=over 4
		1953
		1954	=item IO::AIO::reinit
		1955
		1956	Abandons all current requests and I/O threads and simply reinitialises all
		1957	data structures. This is not an operation supported by any standards, but
		1958	happens to work on GNU/Linux and some newer BSD systems.
		1959
		1960	The only reasonable use for this function is to call it after forking, if
		1961	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1962	the process will result in undefined behaviour. Calling it at any time
		1963	will also result in any undefined (by POSIX) behaviour.
		1964
		1965	=back
1805		1966
1806	=head2 MEMORY USAGE	1967	=head2 MEMORY USAGE
1807		1968
1808	Per-request usage:	1969	Per-request usage:
1809		1970

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.198 by root, Wed Jun 29 11:25:17 2011 UTC vs. Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.198 by root, Wed Jun 29 11:25:17 2011 UTC vs.
Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC