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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs.
Revision 1.219 by root, Tue Mar 27 18:54:45 2012 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 = '4.12';
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_fallocate	178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
179	aio_pathsync aio_readahead	179	aio_pathsync aio_readahead
180	aio_rename aio_link aio_move aio_copy aio_group	180	aio_rename aio_link aio_move aio_copy aio_group
181	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
182	aio_chmod aio_utime aio_truncate	182	aio_chmod aio_utime aio_truncate
183	aio_msync aio_mtouch aio_mlock aio_mlockall	183	aio_msync aio_mtouch aio_mlock aio_mlockall
184	aio_statvfs);	184	aio_statvfs
		185	aio_wd);
185		186
186	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	187	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
187	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	188	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
188	min_parallel max_parallel max_idle idle_timeout	189	min_parallel max_parallel max_idle idle_timeout
189	nreqs nready npending nthreads	190	nreqs nready npending nthreads
…		…
205		206
206	This section simply lists the prototypes of the most important functions	207	This section simply lists the prototypes of the most important functions
207	for quick reference. See the following sections for function-by-function	208	for quick reference. See the following sections for function-by-function
208	documentation.	209	documentation.
209		210
		211	aio_wd $pathname, $callback->($wd)
210	aio_open $pathname, $flags, $mode, $callback->($fh)	212	aio_open $pathname, $flags, $mode, $callback->($fh)
211	aio_close $fh, $callback->($status)	213	aio_close $fh, $callback->($status)
212	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	214	aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	215	aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
214	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	216	aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
…		…
219	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	221	aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
220	aio_chown $fh_or_path, $uid, $gid, $callback->($status)	222	aio_chown $fh_or_path, $uid, $gid, $callback->($status)
221	aio_truncate $fh_or_path, $offset, $callback->($status)	223	aio_truncate $fh_or_path, $offset, $callback->($status)
222	aio_chmod $fh_or_path, $mode, $callback->($status)	224	aio_chmod $fh_or_path, $mode, $callback->($status)
223	aio_unlink $pathname, $callback->($status)	225	aio_unlink $pathname, $callback->($status)
224	aio_mknod $path, $mode, $dev, $callback->($status)	226	aio_mknod $pathname, $mode, $dev, $callback->($status)
225	aio_link $srcpath, $dstpath, $callback->($status)	227	aio_link $srcpath, $dstpath, $callback->($status)
226	aio_symlink $srcpath, $dstpath, $callback->($status)	228	aio_symlink $srcpath, $dstpath, $callback->($status)
227	aio_readlink $path, $callback->($link)	229	aio_readlink $pathname, $callback->($link)
228	aio_realpath $path, $callback->($link)	230	aio_realpath $pathname, $callback->($link)
229	aio_rename $srcpath, $dstpath, $callback->($status)	231	aio_rename $srcpath, $dstpath, $callback->($status)
230	aio_mkdir $pathname, $mode, $callback->($status)	232	aio_mkdir $pathname, $mode, $callback->($status)
231	aio_rmdir $pathname, $callback->($status)	233	aio_rmdir $pathname, $callback->($status)
232	aio_readdir $pathname, $callback->($entries)	234	aio_readdir $pathname, $callback->($entries)
233	aio_readdirx $pathname, $flags, $callback->($entries, $flags)	235	aio_readdirx $pathname, $flags, $callback->($entries, $flags)
234	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST	236	IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
235	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN	237	IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
		238	aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
236	aio_load $path, $data, $callback->($status)	239	aio_load $pathname, $data, $callback->($status)
237	aio_copy $srcpath, $dstpath, $callback->($status)	240	aio_copy $srcpath, $dstpath, $callback->($status)
238	aio_move $srcpath, $dstpath, $callback->($status)	241	aio_move $srcpath, $dstpath, $callback->($status)
239	aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
240	aio_rmtree $path, $callback->($status)	242	aio_rmtree $pathname, $callback->($status)
241	aio_sync $callback->($status)	243	aio_sync $callback->($status)
		244	aio_syncfs $fh, $callback->($status)
242	aio_fsync $fh, $callback->($status)	245	aio_fsync $fh, $callback->($status)
243	aio_fdatasync $fh, $callback->($status)	246	aio_fdatasync $fh, $callback->($status)
244	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	247	aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
245	aio_pathsync $path, $callback->($status)	248	aio_pathsync $pathname, $callback->($status)
246	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	249	aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
247	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)	250	aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
248	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	251	aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
249	aio_mlockall $flags, $callback->($status)	252	aio_mlockall $flags, $callback->($status)
250	aio_group $callback->(...)	253	aio_group $callback->(...)
…		…
273	IO::AIO::madvise $scalar, $offset, $length, $advice	276	IO::AIO::madvise $scalar, $offset, $length, $advice
274	IO::AIO::mprotect $scalar, $offset, $length, $protect	277	IO::AIO::mprotect $scalar, $offset, $length, $protect
275	IO::AIO::munlock $scalar, $offset = 0, $length = undef	278	IO::AIO::munlock $scalar, $offset = 0, $length = undef
276	IO::AIO::munlockall	279	IO::AIO::munlockall
277		280
278	=head2 AIO REQUEST FUNCTIONS	281	=head2 API NOTES
279		282
280	All the C<aio_*> calls are more or less thin wrappers around the syscall	283	All the C<aio_*> calls are more or less thin wrappers around the syscall
281	with the same name (sans C<aio_>). The arguments are similar or identical,	284	with the same name (sans C<aio_>). The arguments are similar or identical,
282	and they all accept an additional (and optional) C<$callback> argument	285	and they all accept an additional (and optional) C<$callback> argument
283	which must be a code reference. This code reference will get called with	286	which must be a code reference. This code reference will be called after
284	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	287	the syscall has been executed in an asynchronous fashion. The results
285	perl, which usually delivers "false") as its sole argument after the given	288	of the request will be passed as arguments to the callback (and, if an
286	syscall has been executed asynchronously.	289	error occured, in C<$!>) - 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>.
287		295
288	All functions expecting a filehandle keep a copy of the filehandle	296	All functions expecting a filehandle keep a copy of the filehandle
289	internally until the request has finished.	297	internally until the request has finished.
290		298
291	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
292	further manipulation of those requests while they are in-flight.	300	further manipulation of those requests while they are in-flight.
293		301
294	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
295	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
296	request is being executed, the current working directory could have	304	current working directory could have changed. Alternatively, you can
297	changed. Alternatively, you can make sure that you never change the	305	make sure that you never change the current working directory anywhere
298	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
299	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.
300		310
301	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
302	in filenames you got from outside (command line, readdir etc.) without	312	in filenames you got from outside (command line, readdir etc.) without
303	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
304	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
305	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
306	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.
307		318
308	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
309	handles correctly whether it is set or not.	320	handles correctly whether it is set or not.
		321
		322	=head2 AIO REQUEST FUNCTIONS
310		323
311	=over 4	324	=over 4
312		325
313	=item $prev_pri = aioreq_pri [$pri]	326	=item $prev_pri = aioreq_pri [$pri]
314		327
…		…
613		626
614	Asynchronously unlink (delete) a file and call the callback with the	627	Asynchronously unlink (delete) a file and call the callback with the
615	result code.	628	result code.
616		629
617		630
618	=item aio_mknod $path, $mode, $dev, $callback->($status)	631	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
619		632
620	[EXPERIMENTAL]	633	[EXPERIMENTAL]
621		634
622	Asynchronously create a device node (or fifo). See mknod(2).	635	Asynchronously create a device node (or fifo). See mknod(2).
623		636
624	The only (POSIX-) portable way of calling this function is:	637	The only (POSIX-) portable way of calling this function is:
625		638
626	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	639	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
627		640
628	See C<aio_stat> for info about some potentially helpful extra constants	641	See C<aio_stat> for info about some potentially helpful extra constants
629	and functions.	642	and functions.
630		643
631	=item aio_link $srcpath, $dstpath, $callback->($status)	644	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
638		651
639	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	652	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
640	the path C<$dstpath> and call the callback with the result code.	653	the path C<$dstpath> and call the callback with the result code.
641		654
642		655
643	=item aio_readlink $path, $callback->($link)	656	=item aio_readlink $pathname, $callback->($link)
644		657
645	Asynchronously read the symlink specified by C<$path> and pass it to	658	Asynchronously read the symlink specified by C<$path> and pass it to
646	the callback. If an error occurs, nothing or undef gets passed to the	659	the callback. If an error occurs, nothing or undef gets passed to the
647	callback.	660	callback.
648		661
649		662
650	=item aio_realpath $path, $callback->($path)	663	=item aio_realpath $pathname, $callback->($path)
651		664
652	Asynchronously make the path absolute and resolve any symlinks in	665	Asynchronously make the path absolute and resolve any symlinks in
653	C<$path>. The resulting path only consists of directories (Same as	666	C<$path>. The resulting path only consists of directories (Same as
654	L<Cwd::realpath>).	667	L<Cwd::realpath>).
655		668
…		…
686	array-ref with the filenames.	699	array-ref with the filenames.
687		700
688		701
689	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	702	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
690		703
691	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	704	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
692	behaviour and output format. In case of an error, C<$entries> will be	705	tune behaviour and output format. In case of an error, C<$entries> will be
693	C<undef>.	706	C<undef>.
694		707
695	The flags are a combination of the following constants, ORed together (the	708	The flags are a combination of the following constants, ORed together (the
696	flags will also be passed to the callback, possibly modified):	709	flags will also be passed to the callback, possibly modified):
697		710
…		…
744		757
745	=item IO::AIO::READDIR_FOUND_UNKNOWN	758	=item IO::AIO::READDIR_FOUND_UNKNOWN
746		759
747	This flag should not be set when calling C<aio_readdirx>. Instead, it	760	This flag should not be set when calling C<aio_readdirx>. Instead, it
748	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	761	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
749	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	762	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
750	C<$type>'s are known, which can be used to speed up some algorithms.	763	C<$type>'s are known, which can be used to speed up some algorithms.
751		764
752	=back	765	=back
753		766
754		767
755	=item aio_load $path, $data, $callback->($status)	768	=item aio_load $pathname, $data, $callback->($status)
756		769
757	This is a composite request that tries to fully load the given file into	770	This is a composite request that tries to fully load the given file into
758	memory. Status is the same as with aio_read.	771	memory. Status is the same as with aio_read.
759		772
760	=cut	773	=cut
…		…
895	};	908	};
896		909
897	$grp	910	$grp
898	}	911	}
899		912
900	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	913	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
901		914
902	Scans a directory (similar to C<aio_readdir>) but additionally tries to	915	Scans a directory (similar to C<aio_readdir>) but additionally tries to
903	efficiently separate the entries of directory C<$path> into two sets of	916	efficiently separate the entries of directory C<$path> into two sets of
904	names, directories you can recurse into (directories), and ones you cannot	917	names, directories you can recurse into (directories), and ones you cannot
905	recurse into (everything else, including symlinks to directories).	918	recurse into (everything else, including symlinks to directories).
…		…
936	Then entries will be sorted into likely directories a non-initial dot	949	Then entries will be sorted into likely directories a non-initial dot
937	currently) and likely non-directories (see C<aio_readdirx>). Then every	950	currently) and likely non-directories (see C<aio_readdirx>). Then every
938	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	951	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
939	in order of their inode numbers. If that succeeds, it assumes that the	952	in order of their inode numbers. If that succeeds, it assumes that the
940	entry is a directory or a symlink to directory (which will be checked	953	entry is a directory or a symlink to directory (which will be checked
941	seperately). This is often faster than stat'ing the entry itself because	954	separately). This is often faster than stat'ing the entry itself because
942	filesystems might detect the type of the entry without reading the inode	955	filesystems might detect the type of the entry without reading the inode
943	data (e.g. ext2fs filetype feature), even on systems that cannot return	956	data (e.g. ext2fs filetype feature), even on systems that cannot return
944	the filetype information on readdir.	957	the filetype information on readdir.
945		958
946	If the known number of directories (link count - 2) has been reached, the	959	If the known number of directories (link count - 2) has been reached, the
…		…
962		975
963	my $grp = aio_group $cb;	976	my $grp = aio_group $cb;
964		977
965	$maxreq = 4 if $maxreq <= 0;	978	$maxreq = 4 if $maxreq <= 0;
966		979
967	# stat once	980	# get a wd object
968	aioreq_pri $pri;	981	aioreq_pri $pri;
969	add $grp aio_stat $path, sub {	982	add $grp aio_wd $path, sub {
		983	$_[0]
970	return $grp->result () if $_[0];	984	or return $grp->result ();
971	my $now = time;
972	my $hash1 = join ":", (stat _)[0,1,3,7,9];
973		985
974	# read the directory entries	986	my $wd = [shift, "."];
		987
		988	# stat once
975	aioreq_pri $pri;	989	aioreq_pri $pri;
976	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	990	add $grp aio_stat $wd, sub {
977	my $entries = shift
978	or return $grp->result ();	991	return $grp->result () if $_[0];
		992	my $now = time;
		993	my $hash1 = join ":", (stat _)[0,1,3,7,9];
979		994
980	# stat the dir another time	995	# read the directory entries
981	aioreq_pri $pri;	996	aioreq_pri $pri;
		997	add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
		998	my $entries = shift
		999	or return $grp->result ();
		1000
		1001	# stat the dir another time
		1002	aioreq_pri $pri;
982	add $grp aio_stat $path, sub {	1003	add $grp aio_stat $wd, sub {
983	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1004	my $hash2 = join ":", (stat _)[0,1,3,7,9];
984		1005
985	my $ndirs;	1006	my $ndirs;
986		1007
987	# take the slow route if anything looks fishy	1008	# take the slow route if anything looks fishy
988	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1009	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
989	$ndirs = -1;	1010	$ndirs = -1;
990	} else {	1011	} else {
991	# if nlink == 2, we are finished	1012	# if nlink == 2, we are finished
992	# for non-posix-fs's, we rely on nlink < 2	1013	# for non-posix-fs's, we rely on nlink < 2
993	$ndirs = (stat _)[3] - 2	1014	$ndirs = (stat _)[3] - 2
994	or return $grp->result ([], $entries);	1015	or return $grp->result ([], $entries);
995	}	1016	}
996		1017
997	my (@dirs, @nondirs);	1018	my (@dirs, @nondirs);
998		1019
999	my $statgrp = add $grp aio_group sub {	1020	my $statgrp = add $grp aio_group sub {
1000	$grp->result (\@dirs, \@nondirs);	1021	$grp->result (\@dirs, \@nondirs);
1001	};	1022	};
1002		1023
1003	limit $statgrp $maxreq;	1024	limit $statgrp $maxreq;
1004	feed $statgrp sub {	1025	feed $statgrp sub {
1005	return unless @$entries;	1026	return unless @$entries;
1006	my $entry = shift @$entries;	1027	my $entry = shift @$entries;
1007		1028
1008	aioreq_pri $pri;	1029	aioreq_pri $pri;
		1030	$wd->[1] = "$entry/.";
1009	add $statgrp aio_stat "$path/$entry/.", sub {	1031	add $statgrp aio_stat $wd, sub {
1010	if ($_[0] < 0) {	1032	if ($_[0] < 0) {
1011	push @nondirs, $entry;	1033	push @nondirs, $entry;
1012	} else {	1034	} else {
1013	# need to check for real directory	1035	# need to check for real directory
1014	aioreq_pri $pri;	1036	aioreq_pri $pri;
		1037	$wd->[1] = $entry;
1015	add $statgrp aio_lstat "$path/$entry", sub {	1038	add $statgrp aio_lstat $wd, sub {
1016	if (-d _) {	1039	if (-d _) {
1017	push @dirs, $entry;	1040	push @dirs, $entry;
1018		1041
1019	unless (--$ndirs) {	1042	unless (--$ndirs) {
1020	push @nondirs, @$entries;	1043	push @nondirs, @$entries;
1021	feed $statgrp;	1044	feed $statgrp;
		1045	}
		1046	} else {
		1047	push @nondirs, $entry;
1022	}	1048	}
1023	} else {
1024	push @nondirs, $entry;
1025	}	1049	}
1026	}	1050	}
1027	}	1051	};
1028	};	1052	};
1029	};	1053	};
1030	};	1054	};
1031	};	1055	};
1032	};	1056	};
1033		1057
1034	$grp	1058	$grp
1035	}	1059	}
1036		1060
1037	=item aio_rmtree $path, $callback->($status)	1061	=item aio_rmtree $pathname, $callback->($status)
1038		1062
1039	Delete a directory tree starting (and including) C<$path>, return the	1063	Delete a directory tree starting (and including) C<$path>, return the
1040	status of the final C<rmdir> only. This is a composite request that	1064	status of the final C<rmdir> only. This is a composite request that
1041	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1065	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1042	everything else.	1066	everything else.
…		…
1084	callback with the fdatasync result code.	1108	callback with the fdatasync result code.
1085		1109
1086	If this call isn't available because your OS lacks it or it couldn't be	1110	If this call isn't available because your OS lacks it or it couldn't be
1087	detected, it will be emulated by calling C<fsync> instead.	1111	detected, it will be emulated by calling C<fsync> instead.
1088		1112
		1113	=item aio_syncfs $fh, $callback->($status)
		1114
		1115	Asynchronously call the syncfs syscall to sync the filesystem associated
		1116	to the given filehandle and call the callback with the syncfs result
		1117	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1118	errno to C<ENOSYS> nevertheless.
		1119
1089	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1120	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1090		1121
1091	Sync the data portion of the file specified by C<$offset> and C<$length>	1122	Sync the data portion of the file specified by C<$offset> and C<$length>
1092	to disk (but NOT the metadata), by calling the Linux-specific	1123	to disk (but NOT the metadata), by calling the Linux-specific
1093	sync_file_range call. If sync_file_range is not available or it returns	1124	sync_file_range call. If sync_file_range is not available or it returns
…		…
1096	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1127	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1097	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1128	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1098	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1129	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1099	manpage for details.	1130	manpage for details.
1100		1131
1101	=item aio_pathsync $path, $callback->($status)	1132	=item aio_pathsync $pathname, $callback->($status)
1102		1133
1103	This request tries to open, fsync and close the given path. This is a	1134	This request tries to open, fsync and close the given path. This is a
1104	composite request intended to sync directories after directory operations	1135	composite request intended to sync directories after directory operations
1105	(E.g. rename). This might not work on all operating systems or have any	1136	(E.g. rename). This might not work on all operating systems or have any
1106	specific effect, but usually it makes sure that directory changes get	1137	specific effect, but usually it makes sure that directory changes get
…		…
1249	immense (it blocks a thread for a long time) so do not use this function	1280	immense (it blocks a thread for a long time) so do not use this function
1250	except to put your application under artificial I/O pressure.	1281	except to put your application under artificial I/O pressure.
1251		1282
1252	=back	1283	=back
1253		1284
		1285
		1286	=head2 IO::AIO::WD - multiple working directories
		1287
		1288	Your process only has one current working directory, which is used by all
		1289	threads. This makes it hard to use relative paths (some other component
		1290	could call C<chdir> at any time, and it is hard to control when the path
		1291	will be used by IO::AIO).
		1292
		1293	One solution for this is to always use absolute paths. This usually works,
		1294	but can be quite slow (the kernel has to walk the whole path on every
		1295	access), and can also be a hassle to implement.
		1296
		1297	Newer POSIX systems have a number of functions (openat, fdopendir,
		1298	futimensat and so on) that make it possible to specify working directories
		1299	per operation.
		1300
		1301	For portability, and because the clowns who "designed", or shall I write,
		1302	perpetrated this new interface were obviously half-drunk, this abstraction
		1303	cannot be perfect, though.
		1304
		1305	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1306	object. This object stores the canonicalised, absolute version of the
		1307	path, and on systems that allow it, also a directory file descriptor.
		1308
		1309	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1310	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1311	object and a pathname instead (or the IO::AIO::WD object alone, which
		1312	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1313	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1314	to that IO::AIO::WD object.
		1315
		1316	For example, to get a wd object for F</etc> and then stat F<passwd>
		1317	inside, you would write:
		1318
		1319	aio_wd "/etc", sub {
		1320	my $etcdir = shift;
		1321
		1322	# although $etcdir can be undef on error, there is generally no reason
		1323	# to check for errors here, as aio_stat will fail with ENOENT
		1324	# when $etcdir is undef.
		1325
		1326	aio_stat [$etcdir, "passwd"], sub {
		1327	# yay
		1328	};
		1329	};
		1330
		1331	That C<aio_wd> is a request and not a normal function shows that creating
		1332	an IO::AIO::WD object is itself a potentially blocking operation, which is
		1333	why it is done asynchronously.
		1334
		1335	To stat the directory obtained with C<aio_wd> above, one could write
		1336	either of the following three request calls:
		1337
		1338	aio_lstat "/etc" , sub { ... # pathname as normal string
		1339	aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
		1340	aio_lstat $wd , sub { ... # shorthand for the previous
		1341
		1342	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1343	object and the pathname string, so you could write the following without
		1344	causing any issues due to C<$path> getting reused:
		1345
		1346	my $path = [$wd, undef];
		1347
		1348	for my $name (qw(abc def ghi)) {
		1349	$path->[1] = $name;
		1350	aio_stat $path, sub {
		1351	# ...
		1352	};
		1353	}
		1354
		1355	There are some caveats: when directories get renamed (or deleted), the
		1356	pathname string doesn't change, so will point to the new directory (or
		1357	nowhere at all), while the directory fd, if available on the system,
		1358	will still point to the original directory. Most functions accepting a
		1359	pathname will use the directory fd on newer systems, and the string on
		1360	older systems. Some functions (such as realpath) will always rely on the
		1361	string form of the pathname.
		1362
		1363	So this fucntionality is mainly useful to get some protection against
		1364	C<chdir>, to easily get an absolute path out of a relative path for future
		1365	reference, and to speed up doing many operations in the same directory
		1366	(e.g. when stat'ing all files in a directory).
		1367
		1368	The following functions implement this working directory abstraction:
		1369
		1370	=over 4
		1371
		1372	=item aio_wd $pathname, $callback->($wd)
		1373
		1374	Asynchonously canonicalise the given pathname and convert it to an
		1375	IO::AIO::WD object representing it. If possible and supported on the
		1376	system, also open a directory fd to speed up pathname resolution relative
		1377	to this working directory.
		1378
		1379	If something goes wrong, then C<undef> is passwd to the callback instead
		1380	of a working directory object and C<$!> is set appropriately. Since
		1381	passing C<undef> as working directory component of a pathname fails the
		1382	request with C<ENOENT>, there is often no need for error checking in the
		1383	C<aio_wd> callback, as future requests using the value will fail in the
		1384	expected way.
		1385
		1386	If this call isn't available because your OS lacks it or it couldn't be
		1387	detected, it will be emulated by calling C<fsync> instead.
		1388
		1389	=item IO::AIO::CWD
		1390
		1391	This is a compiletime constant (object) that represents the process
		1392	current working directory.
		1393
		1394	Specifying this object as working directory object for a pathname is as
		1395	if the pathname would be specified directly, without a directory object,
		1396	e.g., these calls are functionally identical:
		1397
		1398	aio_stat "somefile", sub { ... };
		1399	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1400
		1401	=back
		1402
		1403
1254	=head2 IO::AIO::REQ CLASS	1404	=head2 IO::AIO::REQ CLASS
1255		1405
1256	All non-aggregate C<aio_*> functions return an object of this class when	1406	All non-aggregate C<aio_*> functions return an object of this class when
1257	called in non-void context.	1407	called in non-void context.
1258		1408
…		…
1375		1525
1376	Sets a feeder/generator on this group: every group can have an attached	1526	Sets a feeder/generator on this group: every group can have an attached
1377	generator that generates requests if idle. The idea behind this is that,	1527	generator that generates requests if idle. The idea behind this is that,
1378	although you could just queue as many requests as you want in a group,	1528	although you could just queue as many requests as you want in a group,
1379	this might starve other requests for a potentially long time. For example,	1529	this might starve other requests for a potentially long time. For example,
1380	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1530	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1381	delaying any later requests for a long time.	1531	requests, delaying any later requests for a long time.
1382		1532
1383	To avoid this, and allow incremental generation of requests, you can	1533	To avoid this, and allow incremental generation of requests, you can
1384	instead a group and set a feeder on it that generates those requests. The	1534	instead a group and set a feeder on it that generates those requests. The
1385	feed callback will be called whenever there are few enough (see C<limit>,	1535	feed callback will be called whenever there are few enough (see C<limit>,
1386	below) requests active in the group itself and is expected to queue more	1536	below) requests active in the group itself and is expected to queue more
…		…
1665		1815
1666	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1816	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1667		1817
1668	Simply calls the C<posix_fadvise> function (see its	1818	Simply calls the C<posix_fadvise> function (see its
1669	manpage for details). The following advice constants are	1819	manpage for details). The following advice constants are
1670	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1820	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1671	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1821	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1672	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	1822	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1673		1823
1674	On systems that do not implement C<posix_fadvise>, this function returns	1824	On systems that do not implement C<posix_fadvise>, this function returns
1675	ENOSYS, otherwise the return value of C<posix_fadvise>.	1825	ENOSYS, otherwise the return value of C<posix_fadvise>.
1676		1826
1677	=item IO::AIO::madvise $scalar, $offset, $len, $advice	1827	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1678		1828
1679	Simply calls the C<posix_madvise> function (see its	1829	Simply calls the C<posix_madvise> function (see its
1680	manpage for details). The following advice constants are	1830	manpage for details). The following advice constants are
1681	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	1831	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1682	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	1832	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1683		1833
1684	On systems that do not implement C<posix_madvise>, this function returns	1834	On systems that do not implement C<posix_madvise>, this function returns
1685	ENOSYS, otherwise the return value of C<posix_madvise>.	1835	ENOSYS, otherwise the return value of C<posix_madvise>.
1686		1836
1687	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	1837	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1688		1838
1689	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	1839	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1690	$scalar (see its manpage for details). The following protect	1840	$scalar (see its manpage for details). The following protect
1691	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	1841	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1692	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	1842	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1693		1843
1694	On systems that do not implement C<mprotect>, this function returns	1844	On systems that do not implement C<mprotect>, this function returns
1695	ENOSYS, otherwise the return value of C<mprotect>.	1845	ENOSYS, otherwise the return value of C<mprotect>.
1696		1846
…		…
1804	=head2 FORK BEHAVIOUR	1954	=head2 FORK BEHAVIOUR
1805		1955
1806	Usage of pthreads in a program changes the semantics of fork	1956	Usage of pthreads in a program changes the semantics of fork
1807	considerably. Specifically, only async-safe functions can be called after	1957	considerably. Specifically, only async-safe functions can be called after
1808	fork. Perl doesn't know about this, so in general, you cannot call fork	1958	fork. Perl doesn't know about this, so in general, you cannot call fork
1809	with defined behaviour in perl. IO::AIO uses pthreads, so this applies,	1959	with defined behaviour in perl if pthreads are involved. IO::AIO uses
1810	but many other extensions and (for inexplicable reasons) perl itself often	1960	pthreads, so this applies, but many other extensions and (for inexplicable
1811	is linked against pthreads, so this limitation applies.	1961	reasons) perl itself often is linked against pthreads, so this limitation
		1962	applies to quite a lot of perls.
1812		1963
1813	Some operating systems have extensions that allow safe use of fork, and	1964	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1814	this module should do "the right thing" on those, and tries on others. At	1965	only works in the process that loaded it. Forking is fully supported, but
1815	the time of this writing (2011) only GNU/Linux supports these extensions	1966	using IO::AIO in the child is not.
1816	to POSIX.	1967
		1968	You might get around by not I<using> IO::AIO before (or after)
		1969	forking. You could also try to call the L<IO::AIO::reinit> function in the
		1970	child:
		1971
		1972	=over 4
		1973
		1974	=item IO::AIO::reinit
		1975
		1976	Abandons all current requests and I/O threads and simply reinitialises all
		1977	data structures. This is not an operation supported by any standards, but
		1978	happens to work on GNU/Linux and some newer BSD systems.
		1979
		1980	The only reasonable use for this function is to call it after forking, if
		1981	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		1982	the process will result in undefined behaviour. Calling it at any time
		1983	will also result in any undefined (by POSIX) behaviour.
		1984
		1985	=back
1817		1986
1818	=head2 MEMORY USAGE	1987	=head2 MEMORY USAGE
1819		1988
1820	Per-request usage:	1989	Per-request usage:
1821		1990

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs. Revision 1.219 by root, Tue Mar 27 18:54:45 2012 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.203 by root, Thu Jul 7 22:36:18 2011 UTC vs.
Revision 1.219 by root, Tue Mar 27 18:54:45 2012 UTC