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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 1.229 by root, Wed Jul 25 16:32:30 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
… …
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)
225 aio_unlink $pathname, $callback->($status) 227 aio_unlink $pathname, $callback->($status)
226 aio_mknod $path, $mode, $dev, $callback->($status) 228 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 229 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 230 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $path, $callback->($link) 231 aio_readlink $pathname, $callback->($link)
230 aio_realpath $path, $callback->($link) 232 aio_realpath $pathname, $callback->($link)
231 aio_rename $srcpath, $dstpath, $callback->($status) 233 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 234 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 235 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 236 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 237 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 238 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 239 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
240 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238 aio_load $path, $data, $callback->($status) 241 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 242 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 243 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $path, $callback->($status) 244 aio_rmtree $pathname, $callback->($status)
243 aio_sync $callback->($status) 245 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 246 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 247 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 248 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 249 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $path, $callback->($status) 250 aio_pathsync $pathname, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 251 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 252 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 253 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status) 254 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...) 255 aio_group $callback->(...)
… …
271 IO::AIO::nready 273 IO::AIO::nready
272 IO::AIO::npending 274 IO::AIO::npending
273 275
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 276 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 277 IO::AIO::fadvise $fh, $offset, $len, $advice
278 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
279 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 280 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 281 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 282 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 283 IO::AIO::munlockall
280 284
281=head2 AIO REQUEST FUNCTIONS 285=head2 API NOTES
282 286
283All the C<aio_*> calls are more or less thin wrappers around the syscall 287All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 288with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 289and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will get called with 290which must be a code reference. This code reference will be called after
287the syscall return code (e.g. most syscalls return C<-1> on error, unlike 291the syscall has been executed in an asynchronous fashion. The results
288perl, which usually delivers "false") as its sole argument after the given 292of the request will be passed as arguments to the callback (and, if an
289syscall has been executed asynchronously. 293error occured, in C<$!>) - for most requests the syscall return code (e.g.
294most syscalls return C<-1> on error, unlike perl, which usually delivers
295"false").
296
297Some requests (such as C<aio_readdir>) pass the actual results and
298communicate failures by passing C<undef>.
290 299
291All functions expecting a filehandle keep a copy of the filehandle 300All functions expecting a filehandle keep a copy of the filehandle
292internally until the request has finished. 301internally until the request has finished.
293 302
294All functions return request objects of type L<IO::AIO::REQ> that allow 303All functions return request objects of type L<IO::AIO::REQ> that allow
295further manipulation of those requests while they are in-flight. 304further manipulation of those requests while they are in-flight.
296 305
297The pathnames you pass to these routines I<must> be absolute and 306The 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 307reason for this is that at the time the request is being executed, the
299request is being executed, the current working directory could have 308current working directory could have changed. Alternatively, you can
300changed. Alternatively, you can make sure that you never change the 309make sure that you never change the current working directory anywhere
301current working directory anywhere in the program and then use relative 310in the program and then use relative paths. You can also take advantage
302paths. 311of IO::AIOs working directory abstraction, that lets you specify paths
312relative to some previously-opened "working directory object" - see the
313description of the C<IO::AIO::WD> class later in this document.
303 314
304To encode pathnames as octets, either make sure you either: a) always pass 315To encode pathnames as octets, either make sure you either: a) always pass
305in filenames you got from outside (command line, readdir etc.) without 316in 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 317tinkering, b) are in your native filesystem encoding, c) use the Encode
307your pathnames to the locale (or other) encoding in effect in the user 318module and encode your pathnames to the locale (or other) encoding in
308environment, d) use Glib::filename_from_unicode on unicode filenames or e) 319effect in the user environment, d) use Glib::filename_from_unicode on
309use something else to ensure your scalar has the correct contents. 320unicode filenames or e) use something else to ensure your scalar has the
321correct contents.
310 322
311This works, btw. independent of the internal UTF-8 bit, which IO::AIO 323This works, btw. independent of the internal UTF-8 bit, which IO::AIO
312handles correctly whether it is set or not. 324handles correctly whether it is set or not.
325
326=head2 AIO REQUEST FUNCTIONS
313 327
314=over 4 328=over 4
315 329
316=item $prev_pri = aioreq_pri [$pri] 330=item $prev_pri = aioreq_pri [$pri]
317 331
… …
399 413
400Or in other words: the file descriptor will be closed, but it will not be 414Or in other words: the file descriptor will be closed, but it will not be
401free for reuse until the perl filehandle is closed. 415free for reuse until the perl filehandle is closed.
402 416
403=cut 417=cut
418
419=item aio_seek $fh, $offset, $whence, $callback->($offs)
420
421Seeks the filehandle to the new C<$offset>, similarly to perl's
422C<sysseek>. The C<$whence> can use the traditional values (C<0> for
423C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
424C<IO::AIO::SEEK_END>).
425
426The resulting absolute offset will be passed to the callback, or C<-1> in
427case of an error.
428
429In theory, the C<$whence> constants could be different than the
430corresponding values from L<Fcntl>, but perl guarantees they are the same,
431so don't panic.
432
433As a GNU/Linux (and maybe Solaris) extension, also the constants
434C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
435could be found. No guarantees about suitability for use in C<aio_seek> or
436Perl's C<sysseek> can be made though, although I would naively assume they
437"just work".
404 438
405=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 439=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
406 440
407=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 441=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
408 442
… …
605=item aio_truncate $fh_or_path, $offset, $callback->($status) 639=item aio_truncate $fh_or_path, $offset, $callback->($status)
606 640
607Works like truncate(2) or ftruncate(2). 641Works like truncate(2) or ftruncate(2).
608 642
609 643
644=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
645
646Allocates or freed disk space according to the C<$mode> argument. See the
647linux C<fallocate> docuemntation for details.
648
649C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
650to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE |
651IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
652
653The file system block size used by C<fallocate> is presumably the
654C<f_bsize> returned by C<statvfs>.
655
656If C<fallocate> isn't available or cannot be emulated (currently no
657emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
658
659
610=item aio_chmod $fh_or_path, $mode, $callback->($status) 660=item aio_chmod $fh_or_path, $mode, $callback->($status)
611 661
612Works like perl's C<chmod> function. 662Works like perl's C<chmod> function.
613 663
614 664
… …
616 666
617Asynchronously unlink (delete) a file and call the callback with the 667Asynchronously unlink (delete) a file and call the callback with the
618result code. 668result code.
619 669
620 670
621=item aio_mknod $path, $mode, $dev, $callback->($status) 671=item aio_mknod $pathname, $mode, $dev, $callback->($status)
622 672
623[EXPERIMENTAL] 673[EXPERIMENTAL]
624 674
625Asynchronously create a device node (or fifo). See mknod(2). 675Asynchronously create a device node (or fifo). See mknod(2).
626 676
627The only (POSIX-) portable way of calling this function is: 677The only (POSIX-) portable way of calling this function is:
628 678
629 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 679 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
630 680
631See C<aio_stat> for info about some potentially helpful extra constants 681See C<aio_stat> for info about some potentially helpful extra constants
632and functions. 682and functions.
633 683
634=item aio_link $srcpath, $dstpath, $callback->($status) 684=item aio_link $srcpath, $dstpath, $callback->($status)
… …
641 691
642Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 692Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
643the path C<$dstpath> and call the callback with the result code. 693the path C<$dstpath> and call the callback with the result code.
644 694
645 695
646=item aio_readlink $path, $callback->($link) 696=item aio_readlink $pathname, $callback->($link)
647 697
648Asynchronously read the symlink specified by C<$path> and pass it to 698Asynchronously read the symlink specified by C<$path> and pass it to
649the callback. If an error occurs, nothing or undef gets passed to the 699the callback. If an error occurs, nothing or undef gets passed to the
650callback. 700callback.
651 701
652 702
653=item aio_realpath $path, $callback->($path) 703=item aio_realpath $pathname, $callback->($path)
654 704
655Asynchronously make the path absolute and resolve any symlinks in 705Asynchronously make the path absolute and resolve any symlinks in
656C<$path>. The resulting path only consists of directories (Same as 706C<$path>. The resulting path only consists of directories (Same as
657L<Cwd::realpath>). 707L<Cwd::realpath>).
658 708
… …
753C<$type>'s are known, which can be used to speed up some algorithms. 803C<$type>'s are known, which can be used to speed up some algorithms.
754 804
755=back 805=back
756 806
757 807
758=item aio_load $path, $data, $callback->($status) 808=item aio_load $pathname, $data, $callback->($status)
759 809
760This is a composite request that tries to fully load the given file into 810This is a composite request that tries to fully load the given file into
761memory. Status is the same as with aio_read. 811memory. Status is the same as with aio_read.
762 812
763=cut 813=cut
… …
898 }; 948 };
899 949
900 $grp 950 $grp
901} 951}
902 952
903=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 953=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
904 954
905Scans a directory (similar to C<aio_readdir>) but additionally tries to 955Scans a directory (similar to C<aio_readdir>) but additionally tries to
906efficiently separate the entries of directory C<$path> into two sets of 956efficiently separate the entries of directory C<$path> into two sets of
907names, directories you can recurse into (directories), and ones you cannot 957names, directories you can recurse into (directories), and ones you cannot
908recurse into (everything else, including symlinks to directories). 958recurse into (everything else, including symlinks to directories).
… …
965 1015
966 my $grp = aio_group $cb; 1016 my $grp = aio_group $cb;
967 1017
968 $maxreq = 4 if $maxreq <= 0; 1018 $maxreq = 4 if $maxreq <= 0;
969 1019
970 # stat once 1020 # get a wd object
971 aioreq_pri $pri; 1021 aioreq_pri $pri;
972 add $grp aio_stat $path, sub { 1022 add $grp aio_wd $path, sub {
1023 $_[0]
973 return $grp->result () if $_[0]; 1024 or return $grp->result ();
974 my $now = time;
975 my $hash1 = join ":", (stat _)[0,1,3,7,9];
976 1025
977 # read the directory entries 1026 my $wd = [shift, "."];
1027
1028 # stat once
978 aioreq_pri $pri; 1029 aioreq_pri $pri;
979 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1030 add $grp aio_stat $wd, sub {
980 my $entries = shift
981 or return $grp->result (); 1031 return $grp->result () if $_[0];
1032 my $now = time;
1033 my $hash1 = join ":", (stat _)[0,1,3,7,9];
982 1034
983 # stat the dir another time 1035 # read the directory entries
984 aioreq_pri $pri; 1036 aioreq_pri $pri;
1037 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
1038 my $entries = shift
1039 or return $grp->result ();
1040
1041 # stat the dir another time
1042 aioreq_pri $pri;
985 add $grp aio_stat $path, sub { 1043 add $grp aio_stat $wd, sub {
986 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1044 my $hash2 = join ":", (stat _)[0,1,3,7,9];
987 1045
988 my $ndirs; 1046 my $ndirs;
989 1047
990 # take the slow route if anything looks fishy 1048 # take the slow route if anything looks fishy
991 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1049 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
992 $ndirs = -1; 1050 $ndirs = -1;
993 } else { 1051 } else {
994 # if nlink == 2, we are finished 1052 # if nlink == 2, we are finished
995 # for non-posix-fs's, we rely on nlink < 2 1053 # for non-posix-fs's, we rely on nlink < 2
996 $ndirs = (stat _)[3] - 2 1054 $ndirs = (stat _)[3] - 2
997 or return $grp->result ([], $entries); 1055 or return $grp->result ([], $entries);
998 } 1056 }
999 1057
1000 my (@dirs, @nondirs); 1058 my (@dirs, @nondirs);
1001 1059
1002 my $statgrp = add $grp aio_group sub { 1060 my $statgrp = add $grp aio_group sub {
1003 $grp->result (\@dirs, \@nondirs); 1061 $grp->result (\@dirs, \@nondirs);
1004 }; 1062 };
1005 1063
1006 limit $statgrp $maxreq; 1064 limit $statgrp $maxreq;
1007 feed $statgrp sub { 1065 feed $statgrp sub {
1008 return unless @$entries; 1066 return unless @$entries;
1009 my $entry = shift @$entries; 1067 my $entry = shift @$entries;
1010 1068
1011 aioreq_pri $pri; 1069 aioreq_pri $pri;
1070 $wd->[1] = "$entry/.";
1012 add $statgrp aio_stat "$path/$entry/.", sub { 1071 add $statgrp aio_stat $wd, sub {
1013 if ($_[0] < 0) { 1072 if ($_[0] < 0) {
1014 push @nondirs, $entry; 1073 push @nondirs, $entry;
1015 } else { 1074 } else {
1016 # need to check for real directory 1075 # need to check for real directory
1017 aioreq_pri $pri; 1076 aioreq_pri $pri;
1077 $wd->[1] = $entry;
1018 add $statgrp aio_lstat "$path/$entry", sub { 1078 add $statgrp aio_lstat $wd, sub {
1019 if (-d _) { 1079 if (-d _) {
1020 push @dirs, $entry; 1080 push @dirs, $entry;
1021 1081
1022 unless (--$ndirs) { 1082 unless (--$ndirs) {
1023 push @nondirs, @$entries; 1083 push @nondirs, @$entries;
1024 feed $statgrp; 1084 feed $statgrp;
1085 }
1086 } else {
1087 push @nondirs, $entry;
1025 } 1088 }
1026 } else {
1027 push @nondirs, $entry;
1028 } 1089 }
1029 } 1090 }
1030 } 1091 };
1031 }; 1092 };
1032 }; 1093 };
1033 }; 1094 };
1034 }; 1095 };
1035 }; 1096 };
1036 1097
1037 $grp 1098 $grp
1038} 1099}
1039 1100
1040=item aio_rmtree $path, $callback->($status) 1101=item aio_rmtree $pathname, $callback->($status)
1041 1102
1042Delete a directory tree starting (and including) C<$path>, return the 1103Delete a directory tree starting (and including) C<$path>, return the
1043status of the final C<rmdir> only. This is a composite request that 1104status of the final C<rmdir> only. This is a composite request that
1044uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1105uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1045everything else. 1106everything else.
… …
1106C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1167C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1107C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1168C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1108C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range 1169C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1109manpage for details. 1170manpage for details.
1110 1171
1111=item aio_pathsync $path, $callback->($status) 1172=item aio_pathsync $pathname, $callback->($status)
1112 1173
1113This request tries to open, fsync and close the given path. This is a 1174This request tries to open, fsync and close the given path. This is a
1114composite request intended to sync directories after directory operations 1175composite request intended to sync directories after directory operations
1115(E.g. rename). This might not work on all operating systems or have any 1176(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 1177specific effect, but usually it makes sure that directory changes get
… …
1213 1274
1214Example: asynchronously lock all current and future pages into memory. 1275Example: asynchronously lock all current and future pages into memory.
1215 1276
1216 aio_mlockall IO::AIO::MCL_FUTURE; 1277 aio_mlockall IO::AIO::MCL_FUTURE;
1217 1278
1279=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1280
1281Queries the extents of the given file (by calling the Linux FIEMAP ioctl,
1282see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the
1283C<ioctl> is not available on your OS, then this rquiest will fail with
1284C<ENOSYS>.
1285
1286C<$start> is the starting offset to query extents for, C<$length> is the
1287size of the range to query - if it is C<undef>, then the whole file will
1288be queried.
1289
1290C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1291C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1292exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1293the data portion.
1294
1295C<$count> is the maximum number of extent records to return. If it is
1296C<undef>, then IO::AIO queries all extents of the file. As a very special
1297case, if it is C<0>, then the callback receives the number of extents
1298instead of the extents themselves.
1299
1300If an error occurs, the callback receives no arguments. The special
1301C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1302
1303Otherwise, the callback receives an array reference with extent
1304structures. Each extent structure is an array reference itself, with the
1305following members:
1306
1307 [$logical, $physical, $length, $flags]
1308
1309Flags is any combination of the following flag values (typically either C<0>
1310or C<IO::AIO::FIEMAP_EXTENT_LAST>):
1311
1312C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1313C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1314C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1315C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1316C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1317C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1318
1218=item aio_group $callback->(...) 1319=item aio_group $callback->(...)
1219 1320
1220This is a very special aio request: Instead of doing something, it is a 1321This 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 1322container for other aio requests, which is useful if you want to bundle
1222many requests into a single, composite, request with a definite callback 1323many requests into a single, composite, request with a definite callback
… …
1258like sleep and file handle readable/writable, the overhead this creates is 1359like 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 1360immense (it blocks a thread for a long time) so do not use this function
1260except to put your application under artificial I/O pressure. 1361except to put your application under artificial I/O pressure.
1261 1362
1262=back 1363=back
1364
1365
1366=head2 IO::AIO::WD - multiple working directories
1367
1368Your process only has one current working directory, which is used by all
1369threads. This makes it hard to use relative paths (some other component
1370could call C<chdir> at any time, and it is hard to control when the path
1371will be used by IO::AIO).
1372
1373One solution for this is to always use absolute paths. This usually works,
1374but can be quite slow (the kernel has to walk the whole path on every
1375access), and can also be a hassle to implement.
1376
1377Newer POSIX systems have a number of functions (openat, fdopendir,
1378futimensat and so on) that make it possible to specify working directories
1379per operation.
1380
1381For portability, and because the clowns who "designed", or shall I write,
1382perpetrated this new interface were obviously half-drunk, this abstraction
1383cannot be perfect, though.
1384
1385IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1386object. This object stores the canonicalised, absolute version of the
1387path, and on systems that allow it, also a directory file descriptor.
1388
1389Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1390or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1391object and a pathname instead (or the IO::AIO::WD object alone, which
1392gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1393IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1394to that IO::AIO::WD object.
1395
1396For example, to get a wd object for F</etc> and then stat F<passwd>
1397inside, you would write:
1398
1399 aio_wd "/etc", sub {
1400 my $etcdir = shift;
1401
1402 # although $etcdir can be undef on error, there is generally no reason
1403 # to check for errors here, as aio_stat will fail with ENOENT
1404 # when $etcdir is undef.
1405
1406 aio_stat [$etcdir, "passwd"], sub {
1407 # yay
1408 };
1409 };
1410
1411That C<aio_wd> is a request and not a normal function shows that creating
1412an IO::AIO::WD object is itself a potentially blocking operation, which is
1413why it is done asynchronously.
1414
1415To stat the directory obtained with C<aio_wd> above, one could write
1416either of the following three request calls:
1417
1418 aio_lstat "/etc" , sub { ... # pathname as normal string
1419 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1420 aio_lstat $wd , sub { ... # shorthand for the previous
1421
1422As with normal pathnames, IO::AIO keeps a copy of the working directory
1423object and the pathname string, so you could write the following without
1424causing any issues due to C<$path> getting reused:
1425
1426 my $path = [$wd, undef];
1427
1428 for my $name (qw(abc def ghi)) {
1429 $path->[1] = $name;
1430 aio_stat $path, sub {
1431 # ...
1432 };
1433 }
1434
1435There are some caveats: when directories get renamed (or deleted), the
1436pathname string doesn't change, so will point to the new directory (or
1437nowhere at all), while the directory fd, if available on the system,
1438will still point to the original directory. Most functions accepting a
1439pathname will use the directory fd on newer systems, and the string on
1440older systems. Some functions (such as realpath) will always rely on the
1441string form of the pathname.
1442
1443So this fucntionality is mainly useful to get some protection against
1444C<chdir>, to easily get an absolute path out of a relative path for future
1445reference, and to speed up doing many operations in the same directory
1446(e.g. when stat'ing all files in a directory).
1447
1448The following functions implement this working directory abstraction:
1449
1450=over 4
1451
1452=item aio_wd $pathname, $callback->($wd)
1453
1454Asynchonously canonicalise the given pathname and convert it to an
1455IO::AIO::WD object representing it. If possible and supported on the
1456system, also open a directory fd to speed up pathname resolution relative
1457to this working directory.
1458
1459If something goes wrong, then C<undef> is passwd to the callback instead
1460of a working directory object and C<$!> is set appropriately. Since
1461passing C<undef> as working directory component of a pathname fails the
1462request with C<ENOENT>, there is often no need for error checking in the
1463C<aio_wd> callback, as future requests using the value will fail in the
1464expected way.
1465
1466If this call isn't available because your OS lacks it or it couldn't be
1467detected, it will be emulated by calling C<fsync> instead.
1468
1469=item IO::AIO::CWD
1470
1471This is a compiletime constant (object) that represents the process
1472current working directory.
1473
1474Specifying this object as working directory object for a pathname is as
1475if the pathname would be specified directly, without a directory object,
1476e.g., these calls are functionally identical:
1477
1478 aio_stat "somefile", sub { ... };
1479 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1480
1481=back
1482
1263 1483
1264=head2 IO::AIO::REQ CLASS 1484=head2 IO::AIO::REQ CLASS
1265 1485
1266All non-aggregate C<aio_*> functions return an object of this class when 1486All non-aggregate C<aio_*> functions return an object of this class when
1267called in non-void context. 1487called in non-void context.
… …
1385 1605
1386Sets a feeder/generator on this group: every group can have an attached 1606Sets a feeder/generator on this group: every group can have an attached
1387generator that generates requests if idle. The idea behind this is that, 1607generator 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, 1608although 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, 1609this might starve other requests for a potentially long time. For example,
1390C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1610C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1391delaying any later requests for a long time. 1611requests, delaying any later requests for a long time.
1392 1612
1393To avoid this, and allow incremental generation of requests, you can 1613To avoid this, and allow incremental generation of requests, you can
1394instead a group and set a feeder on it that generates those requests. The 1614instead 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>, 1615feed 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 1616below) requests active in the group itself and is expected to queue more
… …
1705ENOSYS, otherwise the return value of C<mprotect>. 1925ENOSYS, otherwise the return value of C<mprotect>.
1706 1926
1707=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 1927=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1708 1928
1709Memory-maps a file (or anonymous memory range) and attaches it to the 1929Memory-maps a file (or anonymous memory range) and attaches it to the
1710given C<$scalar>, which will act like a string scalar. 1930given C<$scalar>, which will act like a string scalar. Returns true on
1931success, and false otherwise.
1711 1932
1712The only operations allowed on the scalar are C<substr>/C<vec> that don't 1933The 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 1934change the string length, and most read-only operations such as copying it
1714or searching it with regexes and so on. 1935or searching it with regexes and so on.
1715 1936
… …
1768Calls the C<munlockall> function. 1989Calls the C<munlockall> function.
1769 1990
1770On systems that do not implement C<munlockall>, this function returns 1991On systems that do not implement C<munlockall>, this function returns
1771ENOSYS, otherwise the return value of C<munlockall>. 1992ENOSYS, otherwise the return value of C<munlockall>.
1772 1993
1994=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1995
1996Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1997C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
1998should be the file offset.
1999
2000C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2001silently corrupt the data in this case.
2002
2003The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2004C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2005C<IO::AIO::SPLICE_F_GIFT>.
2006
2007See the C<splice(2)> manpage for details.
2008
2009=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2010
2011Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
2012description for C<IO::AIO::splice> above for details.
2013
1773=back 2014=back
1774 2015
1775=cut 2016=cut
1776 2017
1777min_parallel 8; 2018min_parallel 8;

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