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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.201 by root, Tue Jul 5 09:24:11 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 = '3.93';	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_realpath 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)
227	aio_realpath $path, $callback->($link)	230	aio_realpath $pathname, $callback->($link)
228	aio_rename $srcpath, $dstpath, $callback->($status)	231	aio_rename $srcpath, $dstpath, $callback->($status)
229	aio_mkdir $pathname, $mode, $callback->($status)	232	aio_mkdir $pathname, $mode, $callback->($status)
230	aio_rmdir $pathname, $callback->($status)	233	aio_rmdir $pathname, $callback->($status)
231	aio_readdir $pathname, $callback->($entries)	234	aio_readdir $pathname, $callback->($entries)
232	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
233	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
234	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
235	aio_load $path, $data, $callback->($status)	238	aio_load $pathname, $data, $callback->($status)
236	aio_copy $srcpath, $dstpath, $callback->($status)	239	aio_copy $srcpath, $dstpath, $callback->($status)
237	aio_move $srcpath, $dstpath, $callback->($status)	240	aio_move $srcpath, $dstpath, $callback->($status)
238	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	241	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
239	aio_rmtree $path, $callback->($status)	242	aio_rmtree $pathname, $callback->($status)
240	aio_sync $callback->($status)	243	aio_sync $callback->($status)
		244	aio_syncfs $fh, $callback->($status)
241	aio_fsync $fh, $callback->($status)	245	aio_fsync $fh, $callback->($status)
242	aio_fdatasync $fh, $callback->($status)	246	aio_fdatasync $fh, $callback->($status)
243	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
244	aio_pathsync $path, $callback->($status)	248	aio_pathsync $pathname, $callback->($status)
245	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
247	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
248	aio_mlockall $flags, $callback->($status)	252	aio_mlockall $flags, $callback->($status)
249	aio_group $callback->(...)	253	aio_group $callback->(...)
…		…
288	internally until the request has finished.	292	internally until the request has finished.
289		293
290	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
291	further manipulation of those requests while they are in-flight.	295	further manipulation of those requests while they are in-flight.
292		296
293	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
294	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
295	request is being executed, the current working directory could have	299	current working directory could have changed. Alternatively, you can make
296	changed. Alternatively, you can make sure that you never change the	300	sure that you never change the current working directory anywhere in
297	current working directory anywhere in the program and then use relative	301	the program and then use relative paths. Lastly, you can take advantage
298	paths.	302	of IO::AIOs working directory abstraction - see the description of the
		303	C<IO::AIO::WD> class later in this document.
299		304
300	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
301	in filenames you got from outside (command line, readdir etc.) without	306	in filenames you got from outside (command line, readdir etc.) without
302	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
303	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
…		…
612		617
613	Asynchronously unlink (delete) a file and call the callback with the	618	Asynchronously unlink (delete) a file and call the callback with the
614	result code.	619	result code.
615		620
616		621
617	=item aio_mknod $path, $mode, $dev, $callback->($status)	622	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
618		623
619	[EXPERIMENTAL]	624	[EXPERIMENTAL]
620		625
621	Asynchronously create a device node (or fifo). See mknod(2).	626	Asynchronously create a device node (or fifo). See mknod(2).
622		627
623	The only (POSIX-) portable way of calling this function is:	628	The only (POSIX-) portable way of calling this function is:
624		629
625	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	630	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
626		631
627	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
628	and functions.	633	and functions.
629		634
630	=item aio_link $srcpath, $dstpath, $callback->($status)	635	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
637		642
638	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
639	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.
640		645
641		646
642	=item aio_readlink $path, $callback->($link)	647	=item aio_readlink $pathname, $callback->($link)
643		648
644	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
645	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
646	callback.	651	callback.
647		652
648		653
649	=item aio_realpath $path, $callback->($path)	654	=item aio_realpath $pathname, $callback->($path)
650		655
651	Asynchronously make the path absolute and resolve any symlinks in	656	Asynchronously make the path absolute and resolve any symlinks in
652	C<$path>. The resulting path only consists of directories.	657	C<$path>. The resulting path only consists of directories (Same as
		658	L<Cwd::realpath>).
653		659
654	This request can be used to get the absolute path of the current working	660	This request can be used to get the absolute path of the current working
655	directory by passing it a path of F<.> (a single dot).	661	directory by passing it a path of F<.> (a single dot).
656		662
657		663
…		…
684	array-ref with the filenames.	690	array-ref with the filenames.
685		691
686		692
687	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	693	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
688		694
689	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	695	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
690	behaviour and output format. In case of an error, C<$entries> will be	696	tune behaviour and output format. In case of an error, C<$entries> will be
691	C<undef>.	697	C<undef>.
692		698
693	The flags are a combination of the following constants, ORed together (the	699	The flags are a combination of the following constants, ORed together (the
694	flags will also be passed to the callback, possibly modified):	700	flags will also be passed to the callback, possibly modified):
695		701
…		…
742		748
743	=item IO::AIO::READDIR_FOUND_UNKNOWN	749	=item IO::AIO::READDIR_FOUND_UNKNOWN
744		750
745	This flag should not be set when calling C<aio_readdirx>. Instead, it	751	This flag should not be set when calling C<aio_readdirx>. Instead, it
746	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	752	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
747	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	753	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
748	C<$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.
749		755
750	=back	756	=back
751		757
752		758
753	=item aio_load $path, $data, $callback->($status)	759	=item aio_load $pathname, $data, $callback->($status)
754		760
755	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
756	memory. Status is the same as with aio_read.	762	memory. Status is the same as with aio_read.
757		763
758	=cut	764	=cut
…		…
893	};	899	};
894		900
895	$grp	901	$grp
896	}	902	}
897		903
898	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	904	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
899		905
900	Scans a directory (similar to C<aio_readdir>) but additionally tries to	906	Scans a directory (similar to C<aio_readdir>) but additionally tries to
901	efficiently separate the entries of directory C<$path> into two sets of	907	efficiently separate the entries of directory C<$path> into two sets of
902	names, directories you can recurse into (directories), and ones you cannot	908	names, directories you can recurse into (directories), and ones you cannot
903	recurse into (everything else, including symlinks to directories).	909	recurse into (everything else, including symlinks to directories).
…		…
934	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
935	currently) and likely non-directories (see C<aio_readdirx>). Then every	941	currently) and likely non-directories (see C<aio_readdirx>). Then every
936	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,
937	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
938	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
939	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
940	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
941	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
942	the filetype information on readdir.	948	the filetype information on readdir.
943		949
944	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
…		…
960		966
961	my $grp = aio_group $cb;	967	my $grp = aio_group $cb;
962		968
963	$maxreq = 4 if $maxreq <= 0;	969	$maxreq = 4 if $maxreq <= 0;
964		970
965	# stat once	971	# get a wd object
		972
966	aioreq_pri $pri;	973	aioreq_pri $pri;
967	add $grp aio_stat $path, sub {	974	add $grp aio_wd $path, sub {
968	return $grp->result () if $_[0];	975	my $wd = [shift, "."];
969	my $now = time;
970	my $hash1 = join ":", (stat _)[0,1,3,7,9];
971		976
972	# read the directory entries	977	# stat once
973	aioreq_pri $pri;	978	aioreq_pri $pri;
974	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	979	add $grp aio_stat $wd, sub {
975	my $entries = shift
976	or return $grp->result ();	980	return $grp->result () if $_[0];
		981	my $now = time;
		982	my $hash1 = join ":", (stat _)[0,1,3,7,9];
977		983
978	# stat the dir another time	984	# read the directory entries
979	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;
980	add $grp aio_stat $path, sub {	992	add $grp aio_stat $wd, sub {
981	my $hash2 = join ":", (stat _)[0,1,3,7,9];	993	my $hash2 = join ":", (stat _)[0,1,3,7,9];
982		994
983	my $ndirs;	995	my $ndirs;
984		996
985	# take the slow route if anything looks fishy	997	# take the slow route if anything looks fishy
986	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	998	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
987	$ndirs = -1;	999	$ndirs = -1;
988	} else {	1000	} else {
989	# if nlink == 2, we are finished	1001	# if nlink == 2, we are finished
990	# for non-posix-fs's, we rely on nlink < 2	1002	# for non-posix-fs's, we rely on nlink < 2
991	$ndirs = (stat _)[3] - 2	1003	$ndirs = (stat _)[3] - 2
992	or return $grp->result ([], $entries);	1004	or return $grp->result ([], $entries);
993	}	1005	}
994		1006
995	my (@dirs, @nondirs);	1007	my (@dirs, @nondirs);
996		1008
997	my $statgrp = add $grp aio_group sub {	1009	my $statgrp = add $grp aio_group sub {
998	$grp->result (\@dirs, \@nondirs);	1010	$grp->result (\@dirs, \@nondirs);
999	};	1011	};
1000		1012
1001	limit $statgrp $maxreq;	1013	limit $statgrp $maxreq;
1002	feed $statgrp sub {	1014	feed $statgrp sub {
1003	return unless @$entries;	1015	return unless @$entries;
1004	my $entry = shift @$entries;	1016	my $entry = shift @$entries;
1005		1017
1006	aioreq_pri $pri;	1018	aioreq_pri $pri;
		1019	$wd->[1] = "$entry/.";
1007	add $statgrp aio_stat "$path/$entry/.", sub {	1020	add $statgrp aio_stat $wd, sub {
1008	if ($_[0] < 0) {	1021	if ($_[0] < 0) {
1009	push @nondirs, $entry;	1022	push @nondirs, $entry;
1010	} else {	1023	} else {
1011	# need to check for real directory	1024	# need to check for real directory
1012	aioreq_pri $pri;	1025	aioreq_pri $pri;
		1026	$wd->[1] = $entry;
1013	add $statgrp aio_lstat "$path/$entry", sub {	1027	add $statgrp aio_lstat $wd, sub {
1014	if (-d _) {	1028	if (-d _) {
1015	push @dirs, $entry;	1029	push @dirs, $entry;
1016		1030
1017	unless (--$ndirs) {	1031	unless (--$ndirs) {
1018	push @nondirs, @$entries;	1032	push @nondirs, @$entries;
1019	feed $statgrp;	1033	feed $statgrp;
		1034	}
		1035	} else {
		1036	push @nondirs, $entry;
1020	}	1037	}
1021	} else {
1022	push @nondirs, $entry;
1023	}	1038	}
1024	}	1039	}
1025	}	1040	};
1026	};	1041	};
1027	};	1042	};
1028	};	1043	};
1029	};	1044	};
1030	};	1045	};
1031		1046
1032	$grp	1047	$grp
1033	}	1048	}
1034		1049
1035	=item aio_rmtree $path, $callback->($status)	1050	=item aio_rmtree $pathname, $callback->($status)
1036		1051
1037	Delete a directory tree starting (and including) C<$path>, return the	1052	Delete a directory tree starting (and including) C<$path>, return the
1038	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
1039	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
1040	everything else.	1055	everything else.
…		…
1082	callback with the fdatasync result code.	1097	callback with the fdatasync result code.
1083		1098
1084	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
1085	detected, it will be emulated by calling C<fsync> instead.	1100	detected, it will be emulated by calling C<fsync> instead.
1086		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
1087	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1109	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1088		1110
1089	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>
1090	to disk (but NOT the metadata), by calling the Linux-specific	1112	to disk (but NOT the metadata), by calling the Linux-specific
1091	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
…		…
1094	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>,
1095	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1117	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1096	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
1097	manpage for details.	1119	manpage for details.
1098		1120
1099	=item aio_pathsync $path, $callback->($status)	1121	=item aio_pathsync $pathname, $callback->($status)
1100		1122
1101	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
1102	composite request intended to sync directories after directory operations	1124	composite request intended to sync directories after directory operations
1103	(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
1104	specific effect, but usually it makes sure that directory changes get	1126	specific effect, but usually it makes sure that directory changes get
…		…
1247	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
1248	except to put your application under artificial I/O pressure.	1270	except to put your application under artificial I/O pressure.
1249		1271
1250	=back	1272	=back
1251		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
1252	=head2 IO::AIO::REQ CLASS	1384	=head2 IO::AIO::REQ CLASS
1253		1385
1254	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
1255	called in non-void context.	1387	called in non-void context.
1256		1388
…		…
1373		1505
1374	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
1375	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,
1376	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,
1377	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,
1378	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>
1379	delaying any later requests for a long time.	1511	requests, delaying any later requests for a long time.
1380		1512
1381	To avoid this, and allow incremental generation of requests, you can	1513	To avoid this, and allow incremental generation of requests, you can
1382	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
1383	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>,
1384	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
…		…
1663		1795
1664	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1796	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1665		1797
1666	Simply calls the C<posix_fadvise> function (see its	1798	Simply calls the C<posix_fadvise> function (see its
1667	manpage for details). The following advice constants are	1799	manpage for details). The following advice constants are
1668	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1800	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1669	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1801	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1670	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	1802	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1671		1803
1672	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
1673	ENOSYS, otherwise the return value of C<posix_fadvise>.	1805	ENOSYS, otherwise the return value of C<posix_fadvise>.
1674		1806
1675	=item IO::AIO::madvise $scalar, $offset, $len, $advice	1807	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1676		1808
1677	Simply calls the C<posix_madvise> function (see its	1809	Simply calls the C<posix_madvise> function (see its
1678	manpage for details). The following advice constants are	1810	manpage for details). The following advice constants are
1679	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	1811	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1680	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>.
1681		1813
1682	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
1683	ENOSYS, otherwise the return value of C<posix_madvise>.	1815	ENOSYS, otherwise the return value of C<posix_madvise>.
1684		1816
1685	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	1817	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1686		1818
1687	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
1688	$scalar (see its manpage for details). The following protect	1820	$scalar (see its manpage for details). The following protect
1689	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>,
1690	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	1822	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1691		1823
1692	On systems that do not implement C<mprotect>, this function returns	1824	On systems that do not implement C<mprotect>, this function returns
1693	ENOSYS, otherwise the return value of C<mprotect>.	1825	ENOSYS, otherwise the return value of C<mprotect>.
1694		1826
…		…
1802	=head2 FORK BEHAVIOUR	1934	=head2 FORK BEHAVIOUR
1803		1935
1804	Usage of pthreads in a program changes the semantics of fork	1936	Usage of pthreads in a program changes the semantics of fork
1805	considerably. Specifically, only async-safe functions can be called after	1937	considerably. Specifically, only async-safe functions can be called after
1806	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
1807	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
1808	but many other extensions and (for inexplicable reasons) perl itself often	1940	pthreads, so this applies, but many other extensions and (for inexplicable
1809	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.
1810		1943
1811	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
1812	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
1813	the time of this writing (2011) only GNU/Linux supports these extensions	1946	using IO::AIO in the child is not.
1814	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
1815		1966
1816	=head2 MEMORY USAGE	1967	=head2 MEMORY USAGE
1817		1968
1818	Per-request usage:	1969	Per-request usage:
1819		1970

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.201 by root, Tue Jul 5 09:24:11 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 1.201 by root, Tue Jul 5 09:24:11 2011 UTC vs.
Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC