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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.208 by root, Mon Sep 26 20:19:08 2011 UTC vs.
Revision 1.232 by root, Mon Jul 30 16:46:30 2012 UTC

… …
168use common::sense; 168use common::sense;
169 169
170use base 'Exporter'; 170use base 'Exporter';
171 171
172BEGIN { 172BEGIN {
173 our $VERSION = '4.0'; 173 our $VERSION = '4.15';
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_seek 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 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178 aio_fsync aio_syncfs 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 aio_fiemap
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
… …
202 202
203=head1 FUNCTIONS 203=head1 FUNCTIONS
204 204
205=head2 QUICK OVERVIEW 205=head2 QUICK OVERVIEW
206 206
207This section simply lists the prototypes of the most important functions 207This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 208quick reference. See the following sections for function-by-function
209documentation. 209documentation.
210 210
211 aio_wd $pathname, $callback->($wd) 211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 213 aio_close $fh, $callback->($status)
214 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 216 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 217 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 218 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 219 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 220 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 221 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 223 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 225 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 226 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
227 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 228 aio_unlink $pathname, $callback->($status)
226 aio_mknod $path, $mode, $dev, $callback->($status) 229 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 230 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 231 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $path, $callback->($link) 232 aio_readlink $pathname, $callback->($link)
230 aio_realpath $path, $callback->($link) 233 aio_realpath $pathname, $callback->($link)
231 aio_rename $srcpath, $dstpath, $callback->($status) 234 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 235 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 236 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 237 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 238 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 240 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238 aio_load $path, $data, $callback->($status) 242 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 243 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 244 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $path, $callback->($status) 245 aio_rmtree $pathname, $callback->($status)
243 aio_sync $callback->($status) 246 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 247 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 248 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 249 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 250 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $path, $callback->($status) 251 aio_pathsync $pathname, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 252 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 253 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 254 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status) 255 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...) 256 aio_group $callback->(...)
… …
271 IO::AIO::nready 274 IO::AIO::nready
272 IO::AIO::npending 275 IO::AIO::npending
273 276
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 277 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 278 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 281 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 282 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 283 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 284 IO::AIO::munlockall
280 285
281=head2 AIO REQUEST FUNCTIONS 286=head2 API NOTES
282 287
283All the C<aio_*> calls are more or less thin wrappers around the syscall 288All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 289with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 290and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will get called with 291which must be a code reference. This code reference will be called after
287the syscall return code (e.g. most syscalls return C<-1> on error, unlike 292the syscall has been executed in an asynchronous fashion. The results
288perl, which usually delivers "false") as its sole argument after the given 293of the request will be passed as arguments to the callback (and, if an
289syscall has been executed asynchronously. 294error occured, in C<$!>) - for most requests the syscall return code (e.g.
295most syscalls return C<-1> on error, unlike perl, which usually delivers
296"false").
297
298Some requests (such as C<aio_readdir>) pass the actual results and
299communicate failures by passing C<undef>.
290 300
291All functions expecting a filehandle keep a copy of the filehandle 301All functions expecting a filehandle keep a copy of the filehandle
292internally until the request has finished. 302internally until the request has finished.
293 303
294All functions return request objects of type L<IO::AIO::REQ> that allow 304All functions return request objects of type L<IO::AIO::REQ> that allow
295further manipulation of those requests while they are in-flight. 305further manipulation of those requests while they are in-flight.
296 306
297The pathnames you pass to these routines I<must> be absolute and 307The pathnames you pass to these routines I<should> be absolute. The
298encoded as octets. The reason for the former is that at the time the 308reason for this is that at the time the request is being executed, the
299request is being executed, the current working directory could have 309current working directory could have changed. Alternatively, you can
300changed. Alternatively, you can make sure that you never change the 310make sure that you never change the current working directory anywhere
301current working directory anywhere in the program and then use relative 311in the program and then use relative paths. You can also take advantage
302paths. 312of IO::AIOs working directory abstraction, that lets you specify paths
313relative to some previously-opened "working directory object" - see the
314description of the C<IO::AIO::WD> class later in this document.
303 315
304To encode pathnames as octets, either make sure you either: a) always pass 316To encode pathnames as octets, either make sure you either: a) always pass
305in filenames you got from outside (command line, readdir etc.) without 317in filenames you got from outside (command line, readdir etc.) without
306tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 318tinkering, b) are in your native filesystem encoding, c) use the Encode
307your pathnames to the locale (or other) encoding in effect in the user 319module and encode your pathnames to the locale (or other) encoding in
308environment, d) use Glib::filename_from_unicode on unicode filenames or e) 320effect in the user environment, d) use Glib::filename_from_unicode on
309use something else to ensure your scalar has the correct contents. 321unicode filenames or e) use something else to ensure your scalar has the
322correct contents.
310 323
311This works, btw. independent of the internal UTF-8 bit, which IO::AIO 324This works, btw. independent of the internal UTF-8 bit, which IO::AIO
312handles correctly whether it is set or not. 325handles correctly whether it is set or not.
326
327=head2 AIO REQUEST FUNCTIONS
313 328
314=over 4 329=over 4
315 330
316=item $prev_pri = aioreq_pri [$pri] 331=item $prev_pri = aioreq_pri [$pri]
317 332
… …
399 414
400Or in other words: the file descriptor will be closed, but it will not be 415Or in other words: the file descriptor will be closed, but it will not be
401free for reuse until the perl filehandle is closed. 416free for reuse until the perl filehandle is closed.
402 417
403=cut 418=cut
419
420=item aio_seek $fh, $offset, $whence, $callback->($offs)
421
422Seeks the filehandle to the new C<$offset>, similarly to perl's
423C<sysseek>. The C<$whence> can use the traditional values (C<0> for
424C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
425C<IO::AIO::SEEK_END>).
426
427The resulting absolute offset will be passed to the callback, or C<-1> in
428case of an error.
429
430In theory, the C<$whence> constants could be different than the
431corresponding values from L<Fcntl>, but perl guarantees they are the same,
432so don't panic.
433
434As a GNU/Linux (and maybe Solaris) extension, also the constants
435C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
436could be found. No guarantees about suitability for use in C<aio_seek> or
437Perl's C<sysseek> can be made though, although I would naively assume they
438"just work".
404 439
405=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
406 441
407=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
408 443
… …
605=item aio_truncate $fh_or_path, $offset, $callback->($status) 640=item aio_truncate $fh_or_path, $offset, $callback->($status)
606 641
607Works like truncate(2) or ftruncate(2). 642Works like truncate(2) or ftruncate(2).
608 643
609 644
645=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
646
647Allocates or freed disk space according to the C<$mode> argument. See the
648linux C<fallocate> docuemntation for details.
649
650C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
651to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE |
652IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
653
654The file system block size used by C<fallocate> is presumably the
655C<f_bsize> returned by C<statvfs>.
656
657If C<fallocate> isn't available or cannot be emulated (currently no
658emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
659
660
610=item aio_chmod $fh_or_path, $mode, $callback->($status) 661=item aio_chmod $fh_or_path, $mode, $callback->($status)
611 662
612Works like perl's C<chmod> function. 663Works like perl's C<chmod> function.
613 664
614 665
… …
616 667
617Asynchronously unlink (delete) a file and call the callback with the 668Asynchronously unlink (delete) a file and call the callback with the
618result code. 669result code.
619 670
620 671
621=item aio_mknod $path, $mode, $dev, $callback->($status) 672=item aio_mknod $pathname, $mode, $dev, $callback->($status)
622 673
623[EXPERIMENTAL] 674[EXPERIMENTAL]
624 675
625Asynchronously create a device node (or fifo). See mknod(2). 676Asynchronously create a device node (or fifo). See mknod(2).
626 677
627The only (POSIX-) portable way of calling this function is: 678The only (POSIX-) portable way of calling this function is:
628 679
629 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 680 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
630 681
631See C<aio_stat> for info about some potentially helpful extra constants 682See C<aio_stat> for info about some potentially helpful extra constants
632and functions. 683and functions.
633 684
634=item aio_link $srcpath, $dstpath, $callback->($status) 685=item aio_link $srcpath, $dstpath, $callback->($status)
… …
641 692
642Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 693Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
643the path C<$dstpath> and call the callback with the result code. 694the path C<$dstpath> and call the callback with the result code.
644 695
645 696
646=item aio_readlink $path, $callback->($link) 697=item aio_readlink $pathname, $callback->($link)
647 698
648Asynchronously read the symlink specified by C<$path> and pass it to 699Asynchronously read the symlink specified by C<$path> and pass it to
649the callback. If an error occurs, nothing or undef gets passed to the 700the callback. If an error occurs, nothing or undef gets passed to the
650callback. 701callback.
651 702
652 703
653=item aio_realpath $path, $callback->($path) 704=item aio_realpath $pathname, $callback->($path)
654 705
655Asynchronously make the path absolute and resolve any symlinks in 706Asynchronously make the path absolute and resolve any symlinks in
656C<$path>. The resulting path only consists of directories (Same as 707C<$path>. The resulting path only consists of directories (Same as
657L<Cwd::realpath>). 708L<Cwd::realpath>).
658 709
… …
753C<$type>'s are known, which can be used to speed up some algorithms. 804C<$type>'s are known, which can be used to speed up some algorithms.
754 805
755=back 806=back
756 807
757 808
758=item aio_load $path, $data, $callback->($status) 809=item aio_load $pathname, $data, $callback->($status)
759 810
760This is a composite request that tries to fully load the given file into 811This is a composite request that tries to fully load the given file into
761memory. Status is the same as with aio_read. 812memory. Status is the same as with aio_read.
762 813
763=cut 814=cut
… …
898 }; 949 };
899 950
900 $grp 951 $grp
901} 952}
902 953
903=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 954=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
904 955
905Scans a directory (similar to C<aio_readdir>) but additionally tries to 956Scans a directory (similar to C<aio_readdir>) but additionally tries to
906efficiently separate the entries of directory C<$path> into two sets of 957efficiently separate the entries of directory C<$path> into two sets of
907names, directories you can recurse into (directories), and ones you cannot 958names, directories you can recurse into (directories), and ones you cannot
908recurse into (everything else, including symlinks to directories). 959recurse into (everything else, including symlinks to directories).
… …
965 1016
966 my $grp = aio_group $cb; 1017 my $grp = aio_group $cb;
967 1018
968 $maxreq = 4 if $maxreq <= 0; 1019 $maxreq = 4 if $maxreq <= 0;
969 1020
970 # stat once 1021 # get a wd object
971 aioreq_pri $pri; 1022 aioreq_pri $pri;
972 add $grp aio_stat $path, sub { 1023 add $grp aio_wd $path, sub {
1024 $_[0]
973 return $grp->result () if $_[0]; 1025 or return $grp->result ();
974 my $now = time;
975 my $hash1 = join ":", (stat _)[0,1,3,7,9];
976 1026
977 # read the directory entries 1027 my $wd = [shift, "."];
1028
1029 # stat once
978 aioreq_pri $pri; 1030 aioreq_pri $pri;
979 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1031 add $grp aio_stat $wd, sub {
980 my $entries = shift
981 or return $grp->result (); 1032 return $grp->result () if $_[0];
1033 my $now = time;
1034 my $hash1 = join ":", (stat _)[0,1,3,7,9];
982 1035
983 # stat the dir another time 1036 # read the directory entries
984 aioreq_pri $pri; 1037 aioreq_pri $pri;
1038 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
1039 my $entries = shift
1040 or return $grp->result ();
1041
1042 # stat the dir another time
1043 aioreq_pri $pri;
985 add $grp aio_stat $path, sub { 1044 add $grp aio_stat $wd, sub {
986 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1045 my $hash2 = join ":", (stat _)[0,1,3,7,9];
987 1046
988 my $ndirs; 1047 my $ndirs;
989 1048
990 # take the slow route if anything looks fishy 1049 # take the slow route if anything looks fishy
991 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1050 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
992 $ndirs = -1; 1051 $ndirs = -1;
993 } else { 1052 } else {
994 # if nlink == 2, we are finished 1053 # if nlink == 2, we are finished
995 # for non-posix-fs's, we rely on nlink < 2 1054 # for non-posix-fs's, we rely on nlink < 2
996 $ndirs = (stat _)[3] - 2 1055 $ndirs = (stat _)[3] - 2
997 or return $grp->result ([], $entries); 1056 or return $grp->result ([], $entries);
998 } 1057 }
999 1058
1000 my (@dirs, @nondirs); 1059 my (@dirs, @nondirs);
1001 1060
1002 my $statgrp = add $grp aio_group sub { 1061 my $statgrp = add $grp aio_group sub {
1003 $grp->result (\@dirs, \@nondirs); 1062 $grp->result (\@dirs, \@nondirs);
1004 }; 1063 };
1005 1064
1006 limit $statgrp $maxreq; 1065 limit $statgrp $maxreq;
1007 feed $statgrp sub { 1066 feed $statgrp sub {
1008 return unless @$entries; 1067 return unless @$entries;
1009 my $entry = shift @$entries; 1068 my $entry = shift @$entries;
1010 1069
1011 aioreq_pri $pri; 1070 aioreq_pri $pri;
1071 $wd->[1] = "$entry/.";
1012 add $statgrp aio_stat "$path/$entry/.", sub { 1072 add $statgrp aio_stat $wd, sub {
1013 if ($_[0] < 0) { 1073 if ($_[0] < 0) {
1014 push @nondirs, $entry; 1074 push @nondirs, $entry;
1015 } else { 1075 } else {
1016 # need to check for real directory 1076 # need to check for real directory
1017 aioreq_pri $pri; 1077 aioreq_pri $pri;
1078 $wd->[1] = $entry;
1018 add $statgrp aio_lstat "$path/$entry", sub { 1079 add $statgrp aio_lstat $wd, sub {
1019 if (-d _) { 1080 if (-d _) {
1020 push @dirs, $entry; 1081 push @dirs, $entry;
1021 1082
1022 unless (--$ndirs) { 1083 unless (--$ndirs) {
1023 push @nondirs, @$entries; 1084 push @nondirs, @$entries;
1024 feed $statgrp; 1085 feed $statgrp;
1086 }
1087 } else {
1088 push @nondirs, $entry;
1025 } 1089 }
1026 } else {
1027 push @nondirs, $entry;
1028 } 1090 }
1029 } 1091 }
1030 } 1092 };
1031 }; 1093 };
1032 }; 1094 };
1033 }; 1095 };
1034 }; 1096 };
1035 }; 1097 };
1036 1098
1037 $grp 1099 $grp
1038} 1100}
1039 1101
1040=item aio_rmtree $path, $callback->($status) 1102=item aio_rmtree $pathname, $callback->($status)
1041 1103
1042Delete a directory tree starting (and including) C<$path>, return the 1104Delete a directory tree starting (and including) C<$path>, return the
1043status of the final C<rmdir> only. This is a composite request that 1105status of the final C<rmdir> only. This is a composite request that
1044uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1106uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1045everything else. 1107everything else.
… …
1106C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1168C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1107C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1169C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1108C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range 1170C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1109manpage for details. 1171manpage for details.
1110 1172
1111=item aio_pathsync $path, $callback->($status) 1173=item aio_pathsync $pathname, $callback->($status)
1112 1174
1113This request tries to open, fsync and close the given path. This is a 1175This request tries to open, fsync and close the given path. This is a
1114composite request intended to sync directories after directory operations 1176composite request intended to sync directories after directory operations
1115(E.g. rename). This might not work on all operating systems or have any 1177(E.g. rename). This might not work on all operating systems or have any
1116specific effect, but usually it makes sure that directory changes get 1178specific effect, but usually it makes sure that directory changes get
… …
1213 1275
1214Example: asynchronously lock all current and future pages into memory. 1276Example: asynchronously lock all current and future pages into memory.
1215 1277
1216 aio_mlockall IO::AIO::MCL_FUTURE; 1278 aio_mlockall IO::AIO::MCL_FUTURE;
1217 1279
1280=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1281
1282Queries the extents of the given file (by calling the Linux FIEMAP ioctl,
1283see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the
1284C<ioctl> is not available on your OS, then this request will fail with
1285C<ENOSYS>.
1286
1287C<$start> is the starting offset to query extents for, C<$length> is the
1288size of the range to query - if it is C<undef>, then the whole file will
1289be queried.
1290
1291C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1292C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1293exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1294the data portion.
1295
1296C<$count> is the maximum number of extent records to return. If it is
1297C<undef>, then IO::AIO queries all extents of the range. As a very special
1298case, if it is C<0>, then the callback receives the number of extents
1299instead of the extents themselves (which is unreliable, see below).
1300
1301If an error occurs, the callback receives no arguments. The special
1302C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1303
1304Otherwise, the callback receives an array reference with extent
1305structures. Each extent structure is an array reference itself, with the
1306following members:
1307
1308 [$logical, $physical, $length, $flags]
1309
1310Flags is any combination of the following flag values (typically either C<0>
1311or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1312
1313C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1314C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1315C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1316C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1317C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1318C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1319
1320At the time of this writing (Linux 3.2), this requets is unreliable unless
1321C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1322it to return all extents of a range for files with large number of
1323extents. The code works around all these issues if C<$count> is undef.
1324
1218=item aio_group $callback->(...) 1325=item aio_group $callback->(...)
1219 1326
1220This is a very special aio request: Instead of doing something, it is a 1327This is a very special aio request: Instead of doing something, it is a
1221container for other aio requests, which is useful if you want to bundle 1328container for other aio requests, which is useful if you want to bundle
1222many requests into a single, composite, request with a definite callback 1329many requests into a single, composite, request with a definite callback
… …
1258like sleep and file handle readable/writable, the overhead this creates is 1365like sleep and file handle readable/writable, the overhead this creates is
1259immense (it blocks a thread for a long time) so do not use this function 1366immense (it blocks a thread for a long time) so do not use this function
1260except to put your application under artificial I/O pressure. 1367except to put your application under artificial I/O pressure.
1261 1368
1262=back 1369=back
1370
1371
1372=head2 IO::AIO::WD - multiple working directories
1373
1374Your process only has one current working directory, which is used by all
1375threads. This makes it hard to use relative paths (some other component
1376could call C<chdir> at any time, and it is hard to control when the path
1377will be used by IO::AIO).
1378
1379One solution for this is to always use absolute paths. This usually works,
1380but can be quite slow (the kernel has to walk the whole path on every
1381access), and can also be a hassle to implement.
1382
1383Newer POSIX systems have a number of functions (openat, fdopendir,
1384futimensat and so on) that make it possible to specify working directories
1385per operation.
1386
1387For portability, and because the clowns who "designed", or shall I write,
1388perpetrated this new interface were obviously half-drunk, this abstraction
1389cannot be perfect, though.
1390
1391IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1392object. This object stores the canonicalised, absolute version of the
1393path, and on systems that allow it, also a directory file descriptor.
1394
1395Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1396or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1397object and a pathname instead (or the IO::AIO::WD object alone, which
1398gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1399IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1400to that IO::AIO::WD object.
1401
1402For example, to get a wd object for F</etc> and then stat F<passwd>
1403inside, you would write:
1404
1405 aio_wd "/etc", sub {
1406 my $etcdir = shift;
1407
1408 # although $etcdir can be undef on error, there is generally no reason
1409 # to check for errors here, as aio_stat will fail with ENOENT
1410 # when $etcdir is undef.
1411
1412 aio_stat [$etcdir, "passwd"], sub {
1413 # yay
1414 };
1415 };
1416
1417That C<aio_wd> is a request and not a normal function shows that creating
1418an IO::AIO::WD object is itself a potentially blocking operation, which is
1419why it is done asynchronously.
1420
1421To stat the directory obtained with C<aio_wd> above, one could write
1422either of the following three request calls:
1423
1424 aio_lstat "/etc" , sub { ... # pathname as normal string
1425 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1426 aio_lstat $wd , sub { ... # shorthand for the previous
1427
1428As with normal pathnames, IO::AIO keeps a copy of the working directory
1429object and the pathname string, so you could write the following without
1430causing any issues due to C<$path> getting reused:
1431
1432 my $path = [$wd, undef];
1433
1434 for my $name (qw(abc def ghi)) {
1435 $path->[1] = $name;
1436 aio_stat $path, sub {
1437 # ...
1438 };
1439 }
1440
1441There are some caveats: when directories get renamed (or deleted), the
1442pathname string doesn't change, so will point to the new directory (or
1443nowhere at all), while the directory fd, if available on the system,
1444will still point to the original directory. Most functions accepting a
1445pathname will use the directory fd on newer systems, and the string on
1446older systems. Some functions (such as realpath) will always rely on the
1447string form of the pathname.
1448
1449So this fucntionality is mainly useful to get some protection against
1450C<chdir>, to easily get an absolute path out of a relative path for future
1451reference, and to speed up doing many operations in the same directory
1452(e.g. when stat'ing all files in a directory).
1453
1454The following functions implement this working directory abstraction:
1455
1456=over 4
1457
1458=item aio_wd $pathname, $callback->($wd)
1459
1460Asynchonously canonicalise the given pathname and convert it to an
1461IO::AIO::WD object representing it. If possible and supported on the
1462system, also open a directory fd to speed up pathname resolution relative
1463to this working directory.
1464
1465If something goes wrong, then C<undef> is passwd to the callback instead
1466of a working directory object and C<$!> is set appropriately. Since
1467passing C<undef> as working directory component of a pathname fails the
1468request with C<ENOENT>, there is often no need for error checking in the
1469C<aio_wd> callback, as future requests using the value will fail in the
1470expected way.
1471
1472If this call isn't available because your OS lacks it or it couldn't be
1473detected, it will be emulated by calling C<fsync> instead.
1474
1475=item IO::AIO::CWD
1476
1477This is a compiletime constant (object) that represents the process
1478current working directory.
1479
1480Specifying this object as working directory object for a pathname is as
1481if the pathname would be specified directly, without a directory object,
1482e.g., these calls are functionally identical:
1483
1484 aio_stat "somefile", sub { ... };
1485 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1486
1487=back
1488
1263 1489
1264=head2 IO::AIO::REQ CLASS 1490=head2 IO::AIO::REQ CLASS
1265 1491
1266All non-aggregate C<aio_*> functions return an object of this class when 1492All non-aggregate C<aio_*> functions return an object of this class when
1267called in non-void context. 1493called in non-void context.
… …
1385 1611
1386Sets a feeder/generator on this group: every group can have an attached 1612Sets a feeder/generator on this group: every group can have an attached
1387generator that generates requests if idle. The idea behind this is that, 1613generator that generates requests if idle. The idea behind this is that,
1388although you could just queue as many requests as you want in a group, 1614although you could just queue as many requests as you want in a group,
1389this might starve other requests for a potentially long time. For example, 1615this might starve other requests for a potentially long time. For example,
1390C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1616C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1391delaying any later requests for a long time. 1617requests, delaying any later requests for a long time.
1392 1618
1393To avoid this, and allow incremental generation of requests, you can 1619To avoid this, and allow incremental generation of requests, you can
1394instead a group and set a feeder on it that generates those requests. The 1620instead a group and set a feeder on it that generates those requests. The
1395feed callback will be called whenever there are few enough (see C<limit>, 1621feed callback will be called whenever there are few enough (see C<limit>,
1396below) requests active in the group itself and is expected to queue more 1622below) requests active in the group itself and is expected to queue more
… …
1705ENOSYS, otherwise the return value of C<mprotect>. 1931ENOSYS, otherwise the return value of C<mprotect>.
1706 1932
1707=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1933=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1708 1934
1709Memory-maps a file (or anonymous memory range) and attaches it to the 1935Memory-maps a file (or anonymous memory range) and attaches it to the
1710given C<$scalar>, which will act like a string scalar. 1936given C<$scalar>, which will act like a string scalar. Returns true on
1937success, and false otherwise.
1711 1938
1712The only operations allowed on the scalar are C<substr>/C<vec> that don't 1939The only operations allowed on the scalar are C<substr>/C<vec> that don't
1713change the string length, and most read-only operations such as copying it 1940change the string length, and most read-only operations such as copying it
1714or searching it with regexes and so on. 1941or searching it with regexes and so on.
1715 1942
… …
1768Calls the C<munlockall> function. 1995Calls the C<munlockall> function.
1769 1996
1770On systems that do not implement C<munlockall>, this function returns 1997On systems that do not implement C<munlockall>, this function returns
1771ENOSYS, otherwise the return value of C<munlockall>. 1998ENOSYS, otherwise the return value of C<munlockall>.
1772 1999
2000=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2001
2002Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2003C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2004should be the file offset.
2005
2006C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2007silently corrupt the data in this case.
2008
2009The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2010C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2011C<IO::AIO::SPLICE_F_GIFT>.
2012
2013See the C<splice(2)> manpage for details.
2014
2015=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2016
2017Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
2018description for C<IO::AIO::splice> above for details.
2019
1773=back 2020=back
1774 2021
1775=cut 2022=cut
1776 2023
1777min_parallel 8; 2024min_parallel 8;

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