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Revision 1.210 by root, Tue Sep 27 01:43:03 2011 UTC vs.
Revision 1.241 by root, Fri Dec 28 07:33:41 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 = '4.18';
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_allocate
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 $pathname, $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 $pathname, $callback->($link) 232 aio_readlink $pathname, $callback->($link)
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 $pathname, $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 $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $pathname, $callback->($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)
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<should> be absolute. The 307The pathnames you pass to these routines I<should> be absolute. The
298reason for this is that at the time the request is being executed, the 308reason for this is that at the time the request is being executed, the
299current working directory could have changed. Alternatively, you can make 309current working directory could have changed. Alternatively, you can
300sure that you never change the current working directory anywhere in 310make sure that you never change the current working directory anywhere
301the program and then use relative paths. Lastly, you can take advantage 311in the program and then use relative paths. You can also take advantage
302of IO::AIOs working directory abstraction - see the description of the 312of IO::AIOs working directory abstraction, that lets you specify paths
313relative to some previously-opened "working directory object" - see the
303C<IO::AIO::WD> class later in this document. 314description of the C<IO::AIO::WD> class later in this document.
304 315
305To 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
306in filenames you got from outside (command line, readdir etc.) without 317in filenames you got from outside (command line, readdir etc.) without
307tinkering, 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
308your pathnames to the locale (or other) encoding in effect in the user 319module and encode your pathnames to the locale (or other) encoding in
309environment, d) use Glib::filename_from_unicode on unicode filenames or e) 320effect in the user environment, d) use Glib::filename_from_unicode on
310use 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.
311 323
312This 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
313handles correctly whether it is set or not. 325handles correctly whether it is set or not.
326
327=head2 AIO REQUEST FUNCTIONS
314 328
315=over 4 329=over 4
316 330
317=item $prev_pri = aioreq_pri [$pri] 331=item $prev_pri = aioreq_pri [$pri]
318 332
348 362
349 363
350=item aio_open $pathname, $flags, $mode, $callback->($fh) 364=item aio_open $pathname, $flags, $mode, $callback->($fh)
351 365
352Asynchronously open or create a file and call the callback with a newly 366Asynchronously open or create a file and call the callback with a newly
353created filehandle for the file. 367created filehandle for the file (or C<undef> in case of an error).
354 368
355The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 369The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
356for an explanation. 370for an explanation.
357 371
358The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 372The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
400 414
401Or 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
402free for reuse until the perl filehandle is closed. 416free for reuse until the perl filehandle is closed.
403 417
404=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".
405 439
406=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
407 441
408=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
409 443
569 namemax => 255, 603 namemax => 255,
570 frsize => 1024, 604 frsize => 1024,
571 fsid => 1810 605 fsid => 1810
572 } 606 }
573 607
608Here is a (likely partial) list of fsid values used by Linux - it is safe
609to hardcode these when the $^O is C<linux>:
610
611 0x0000adf5 adfs
612 0x0000adff affs
613 0x5346414f afs
614 0x09041934 anon-inode filesystem
615 0x00000187 autofs
616 0x42465331 befs
617 0x1badface bfs
618 0x42494e4d binfmt_misc
619 0x9123683e btrfs
620 0x0027e0eb cgroupfs
621 0xff534d42 cifs
622 0x73757245 coda
623 0x012ff7b7 coh
624 0x28cd3d45 cramfs
625 0x453dcd28 cramfs-wend (wrong endianness)
626 0x64626720 debugfs
627 0x00001373 devfs
628 0x00001cd1 devpts
629 0x0000f15f ecryptfs
630 0x00414a53 efs
631 0x0000137d ext
632 0x0000ef53 ext2/ext3
633 0x0000ef51 ext2
634 0x00004006 fat
635 0x65735546 fuseblk
636 0x65735543 fusectl
637 0x0bad1dea futexfs
638 0x01161970 gfs2
639 0x47504653 gpfs
640 0x00004244 hfs
641 0xf995e849 hpfs
642 0x958458f6 hugetlbfs
643 0x2bad1dea inotifyfs
644 0x00009660 isofs
645 0x000072b6 jffs2
646 0x3153464a jfs
647 0x6b414653 k-afs
648 0x0bd00bd0 lustre
649 0x0000137f minix
650 0x0000138f minix 30 char names
651 0x00002468 minix v2
652 0x00002478 minix v2 30 char names
653 0x00004d5a minix v3
654 0x19800202 mqueue
655 0x00004d44 msdos
656 0x0000564c novell
657 0x00006969 nfs
658 0x6e667364 nfsd
659 0x00003434 nilfs
660 0x5346544e ntfs
661 0x00009fa1 openprom
662 0x7461636F ocfs2
663 0x00009fa0 proc
664 0x6165676c pstorefs
665 0x0000002f qnx4
666 0x858458f6 ramfs
667 0x52654973 reiserfs
668 0x00007275 romfs
669 0x67596969 rpc_pipefs
670 0x73636673 securityfs
671 0xf97cff8c selinux
672 0x0000517b smb
673 0x534f434b sockfs
674 0x73717368 squashfs
675 0x62656572 sysfs
676 0x012ff7b6 sysv2
677 0x012ff7b5 sysv4
678 0x01021994 tmpfs
679 0x15013346 udf
680 0x00011954 ufs
681 0x54190100 ufs byteswapped
682 0x00009fa2 usbdevfs
683 0x01021997 v9fs
684 0xa501fcf5 vxfs
685 0xabba1974 xenfs
686 0x012ff7b4 xenix
687 0x58465342 xfs
688 0x012fd16d xia
574 689
575=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 690=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
576 691
577Works like perl's C<utime> function (including the special case of $atime 692Works like perl's C<utime> function (including the special case of $atime
578and $mtime being undef). Fractional times are supported if the underlying 693and $mtime being undef). Fractional times are supported if the underlying
606=item aio_truncate $fh_or_path, $offset, $callback->($status) 721=item aio_truncate $fh_or_path, $offset, $callback->($status)
607 722
608Works like truncate(2) or ftruncate(2). 723Works like truncate(2) or ftruncate(2).
609 724
610 725
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727
728Allocates or freed disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details.
730
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
732to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE |
733IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
734
735The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>.
737
738If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740
741
611=item aio_chmod $fh_or_path, $mode, $callback->($status) 742=item aio_chmod $fh_or_path, $mode, $callback->($status)
612 743
613Works like perl's C<chmod> function. 744Works like perl's C<chmod> function.
614 745
615 746
652 783
653 784
654=item aio_realpath $pathname, $callback->($path) 785=item aio_realpath $pathname, $callback->($path)
655 786
656Asynchronously make the path absolute and resolve any symlinks in 787Asynchronously make the path absolute and resolve any symlinks in
657C<$path>. The resulting path only consists of directories (Same as 788C<$path>. The resulting path only consists of directories (same as
658L<Cwd::realpath>). 789L<Cwd::realpath>).
659 790
660This request can be used to get the absolute path of the current working 791This request can be used to get the absolute path of the current working
661directory by passing it a path of F<.> (a single dot). 792directory by passing it a path of F<.> (a single dot).
662 793
663 794
664=item aio_rename $srcpath, $dstpath, $callback->($status) 795=item aio_rename $srcpath, $dstpath, $callback->($status)
665 796
666Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 797Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
667rename(2) and call the callback with the result code. 798rename(2) and call the callback with the result code.
799
800On systems that support the AIO::WD working directory abstraction
801natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
802of failing, C<rename> is called on the absolute path of C<$wd>.
668 803
669 804
670=item aio_mkdir $pathname, $mode, $callback->($status) 805=item aio_mkdir $pathname, $mode, $callback->($status)
671 806
672Asynchronously mkdir (create) a directory and call the callback with 807Asynchronously mkdir (create) a directory and call the callback with
676 811
677=item aio_rmdir $pathname, $callback->($status) 812=item aio_rmdir $pathname, $callback->($status)
678 813
679Asynchronously rmdir (delete) a directory and call the callback with the 814Asynchronously rmdir (delete) a directory and call the callback with the
680result code. 815result code.
816
817On systems that support the AIO::WD working directory abstraction
818natively, the case C<[$wd, "."]> is specialcased - instead of failing,
819C<rmdir> is called on the absolute path of C<$wd>.
681 820
682 821
683=item aio_readdir $pathname, $callback->($entries) 822=item aio_readdir $pathname, $callback->($entries)
684 823
685Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 824Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
967 my $grp = aio_group $cb; 1106 my $grp = aio_group $cb;
968 1107
969 $maxreq = 4 if $maxreq <= 0; 1108 $maxreq = 4 if $maxreq <= 0;
970 1109
971 # get a wd object 1110 # get a wd object
972
973 aioreq_pri $pri; 1111 aioreq_pri $pri;
974 add $grp aio_wd $path, sub { 1112 add $grp aio_wd $path, sub {
1113 $_[0]
1114 or return $grp->result ();
1115
975 my $wd = [shift, "."]; 1116 my $wd = [shift, "."];
976 1117
977 # stat once 1118 # stat once
978 aioreq_pri $pri; 1119 aioreq_pri $pri;
979 add $grp aio_stat $wd, sub { 1120 add $grp aio_stat $wd, sub {
1048} 1189}
1049 1190
1050=item aio_rmtree $pathname, $callback->($status) 1191=item aio_rmtree $pathname, $callback->($status)
1051 1192
1052Delete a directory tree starting (and including) C<$path>, return the 1193Delete a directory tree starting (and including) C<$path>, return the
1053status of the final C<rmdir> only. This is a composite request that 1194status of the final C<rmdir> only. This is a composite request that
1054uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1195uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1055everything else. 1196everything else.
1056 1197
1057=cut 1198=cut
1058 1199
1178 1319
1179This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1320This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1180scalars. 1321scalars.
1181 1322
1182It touches (reads or writes) all memory pages in the specified 1323It touches (reads or writes) all memory pages in the specified
1183range inside the scalar. All caveats and parameters are the same 1324range inside the scalar. All caveats and parameters are the same
1184as for C<aio_msync>, above, except for flags, which must be either 1325as for C<aio_msync>, above, except for flags, which must be either
1185C<0> (which reads all pages and ensures they are instantiated) or 1326C<0> (which reads all pages and ensures they are instantiated) or
1186C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1327C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1187writing an octet from it, which dirties the page). 1328writing an octet from it, which dirties the page).
1188 1329
1189=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1330=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1190 1331
1191This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1332This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1222documented under L<MISCELLANEOUS FUNCTIONS>. 1363documented under L<MISCELLANEOUS FUNCTIONS>.
1223 1364
1224Example: asynchronously lock all current and future pages into memory. 1365Example: asynchronously lock all current and future pages into memory.
1225 1366
1226 aio_mlockall IO::AIO::MCL_FUTURE; 1367 aio_mlockall IO::AIO::MCL_FUTURE;
1368
1369=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1370
1371Queries the extents of the given file (by calling the Linux C<FIEMAP>
1372ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1373the ioctl is not available on your OS, then this request will fail with
1374C<ENOSYS>.
1375
1376C<$start> is the starting offset to query extents for, C<$length> is the
1377size of the range to query - if it is C<undef>, then the whole file will
1378be queried.
1379
1380C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1381C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1382exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1383the data portion.
1384
1385C<$count> is the maximum number of extent records to return. If it is
1386C<undef>, then IO::AIO queries all extents of the range. As a very special
1387case, if it is C<0>, then the callback receives the number of extents
1388instead of the extents themselves (which is unreliable, see below).
1389
1390If an error occurs, the callback receives no arguments. The special
1391C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1392
1393Otherwise, the callback receives an array reference with extent
1394structures. Each extent structure is an array reference itself, with the
1395following members:
1396
1397 [$logical, $physical, $length, $flags]
1398
1399Flags is any combination of the following flag values (typically either C<0>
1400or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1401
1402C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1403C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1404C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1405C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1406C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1407C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1408
1409At the time of this writing (Linux 3.2), this requets is unreliable unless
1410C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1411it to return all extents of a range for files with large number of
1412extents. The code works around all these issues if C<$count> is undef.
1227 1413
1228=item aio_group $callback->(...) 1414=item aio_group $callback->(...)
1229 1415
1230This is a very special aio request: Instead of doing something, it is a 1416This is a very special aio request: Instead of doing something, it is a
1231container for other aio requests, which is useful if you want to bundle 1417container for other aio requests, which is useful if you want to bundle
1295object. This object stores the canonicalised, absolute version of the 1481object. This object stores the canonicalised, absolute version of the
1296path, and on systems that allow it, also a directory file descriptor. 1482path, and on systems that allow it, also a directory file descriptor.
1297 1483
1298Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> 1484Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1299or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD 1485or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1300object and a pathname instead. If the pathname is absolute, the 1486object and a pathname instead (or the IO::AIO::WD object alone, which
1487gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1301IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative 1488IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1302to that IO::AIO::WD object. 1489to that IO::AIO::WD object.
1303 1490
1304For example, to get a wd object for F</etc> and then stat F<passwd> 1491For example, to get a wd object for F</etc> and then stat F<passwd>
1305inside, you would write: 1492inside, you would write:
1306 1493
1314 aio_stat [$etcdir, "passwd"], sub { 1501 aio_stat [$etcdir, "passwd"], sub {
1315 # yay 1502 # yay
1316 }; 1503 };
1317 }; 1504 };
1318 1505
1319This shows that creating an IO::AIO::WD object is itself a potentially 1506That C<aio_wd> is a request and not a normal function shows that creating
1320blocking operation, which is why it is done asynchronously. 1507an IO::AIO::WD object is itself a potentially blocking operation, which is
1508why it is done asynchronously.
1509
1510To stat the directory obtained with C<aio_wd> above, one could write
1511either of the following three request calls:
1512
1513 aio_lstat "/etc" , sub { ... # pathname as normal string
1514 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1515 aio_lstat $wd , sub { ... # shorthand for the previous
1321 1516
1322As with normal pathnames, IO::AIO keeps a copy of the working directory 1517As with normal pathnames, IO::AIO keeps a copy of the working directory
1323object and the pathname string, so you could write the following without 1518object and the pathname string, so you could write the following without
1324causing any issues due to C<$path> getting reused: 1519causing any issues due to C<$path> getting reused:
1325 1520
1338will still point to the original directory. Most functions accepting a 1533will still point to the original directory. Most functions accepting a
1339pathname will use the directory fd on newer systems, and the string on 1534pathname will use the directory fd on newer systems, and the string on
1340older systems. Some functions (such as realpath) will always rely on the 1535older systems. Some functions (such as realpath) will always rely on the
1341string form of the pathname. 1536string form of the pathname.
1342 1537
1343So this fucntionality is mainly useful to get some protection against 1538So this functionality is mainly useful to get some protection against
1344C<chdir>, to easily get an absolute path out of a relative path for future 1539C<chdir>, to easily get an absolute path out of a relative path for future
1345reference, and to speed up doing many operations in the same directory 1540reference, and to speed up doing many operations in the same directory
1346(e.g. when stat'ing all files in a directory). 1541(e.g. when stat'ing all files in a directory).
1347 1542
1348The following functions implement this working directory abstraction: 1543The following functions implement this working directory abstraction:
1369=item IO::AIO::CWD 1564=item IO::AIO::CWD
1370 1565
1371This is a compiletime constant (object) that represents the process 1566This is a compiletime constant (object) that represents the process
1372current working directory. 1567current working directory.
1373 1568
1374Specifying this object as working directory object for a pathname is as 1569Specifying this object as working directory object for a pathname is as if
1375if the pathname would be specified directly, without a directory object, 1570the pathname would be specified directly, without a directory object. For
1376e.g., these calls are functionally identical: 1571example, these calls are functionally identical:
1377 1572
1378 aio_stat "somefile", sub { ... }; 1573 aio_stat "somefile", sub { ... };
1379 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1574 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1380 1575
1381=back 1576=back
1382 1577
1578To recover the path associated with an IO::AIO::WD object, you can use
1579C<aio_realpath>:
1580
1581 aio_realpath $wd, sub {
1582 warn "path is $_[0]\n";
1583 };
1584
1585Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1586sometimes, fall back to using an absolue path.
1383 1587
1384=head2 IO::AIO::REQ CLASS 1588=head2 IO::AIO::REQ CLASS
1385 1589
1386All non-aggregate C<aio_*> functions return an object of this class when 1590All non-aggregate C<aio_*> functions return an object of this class when
1387called in non-void context. 1591called in non-void context.
1505 1709
1506Sets a feeder/generator on this group: every group can have an attached 1710Sets a feeder/generator on this group: every group can have an attached
1507generator that generates requests if idle. The idea behind this is that, 1711generator that generates requests if idle. The idea behind this is that,
1508although you could just queue as many requests as you want in a group, 1712although you could just queue as many requests as you want in a group,
1509this might starve other requests for a potentially long time. For example, 1713this might starve other requests for a potentially long time. For example,
1510C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1714C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1511delaying any later requests for a long time. 1715requests, delaying any later requests for a long time.
1512 1716
1513To avoid this, and allow incremental generation of requests, you can 1717To avoid this, and allow incremental generation of requests, you can
1514instead a group and set a feeder on it that generates those requests. The 1718instead a group and set a feeder on it that generates those requests. The
1515feed callback will be called whenever there are few enough (see C<limit>, 1719feed callback will be called whenever there are few enough (see C<limit>,
1516below) requests active in the group itself and is expected to queue more 1720below) requests active in the group itself and is expected to queue more
1565 1769
1566See C<poll_cb> for an example. 1770See C<poll_cb> for an example.
1567 1771
1568=item IO::AIO::poll_cb 1772=item IO::AIO::poll_cb
1569 1773
1570Process some outstanding events on the result pipe. You have to call 1774Process some requests that have reached the result phase (i.e. they have
1775been executed but the results are not yet reported). You have to call
1776this "regularly" to finish outstanding requests.
1777
1571this regularly. Returns C<0> if all events could be processed (or there 1778Returns C<0> if all events could be processed (or there were no
1572were no events to process), or C<-1> if it returned earlier for whatever 1779events to process), or C<-1> if it returned earlier for whatever
1573reason. Returns immediately when no events are outstanding. The amount of 1780reason. Returns immediately when no events are outstanding. The amount
1574events processed depends on the settings of C<IO::AIO::max_poll_req> and 1781of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1575C<IO::AIO::max_poll_time>. 1782C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1576 1783
1577If not all requests were processed for whatever reason, the filehandle 1784If not all requests were processed for whatever reason, the poll file
1578will still be ready when C<poll_cb> returns, so normally you don't have to 1785descriptor will still be ready when C<poll_cb> returns, so normally you
1579do anything special to have it called later. 1786don't have to do anything special to have it called later.
1580 1787
1581Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1788Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1582ready, it can be beneficial to call this function from loops which submit 1789ready, it can be beneficial to call this function from loops which submit
1583a lot of requests, to make sure the results get processed when they become 1790a lot of requests, to make sure the results get processed when they become
1584available and not just when the loop is finished and the event loop takes 1791available and not just when the loop is finished and the event loop takes
1593 poll => 'r', async => 1, 1800 poll => 'r', async => 1,
1594 cb => \&IO::AIO::poll_cb); 1801 cb => \&IO::AIO::poll_cb);
1595 1802
1596=item IO::AIO::poll_wait 1803=item IO::AIO::poll_wait
1597 1804
1598If there are any outstanding requests and none of them in the result 1805Wait until either at least one request is in the result phase or no
1599phase, wait till the result filehandle becomes ready for reading (simply 1806requests are outstanding anymore.
1600does a C<select> on the filehandle. This is useful if you want to 1807
1601synchronously wait for some requests to finish). 1808This is useful if you want to synchronously wait for some requests to
1809become ready, without actually handling them.
1602 1810
1603See C<nreqs> for an example. 1811See C<nreqs> for an example.
1604 1812
1605=item IO::AIO::poll 1813=item IO::AIO::poll
1606 1814
1825ENOSYS, otherwise the return value of C<mprotect>. 2033ENOSYS, otherwise the return value of C<mprotect>.
1826 2034
1827=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2035=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1828 2036
1829Memory-maps a file (or anonymous memory range) and attaches it to the 2037Memory-maps a file (or anonymous memory range) and attaches it to the
1830given C<$scalar>, which will act like a string scalar. 2038given C<$scalar>, which will act like a string scalar. Returns true on
2039success, and false otherwise.
1831 2040
1832The only operations allowed on the scalar are C<substr>/C<vec> that don't 2041The only operations allowed on the scalar are C<substr>/C<vec> that don't
1833change the string length, and most read-only operations such as copying it 2042change the string length, and most read-only operations such as copying it
1834or searching it with regexes and so on. 2043or searching it with regexes and so on.
1835 2044
1888Calls the C<munlockall> function. 2097Calls the C<munlockall> function.
1889 2098
1890On systems that do not implement C<munlockall>, this function returns 2099On systems that do not implement C<munlockall>, this function returns
1891ENOSYS, otherwise the return value of C<munlockall>. 2100ENOSYS, otherwise the return value of C<munlockall>.
1892 2101
2102=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2103
2104Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2105C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2106should be the file offset.
2107
2108C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2109silently corrupt the data in this case.
2110
2111The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2112C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2113C<IO::AIO::SPLICE_F_GIFT>.
2114
2115See the C<splice(2)> manpage for details.
2116
2117=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2118
2119Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
2120description for C<IO::AIO::splice> above for details.
2121
1893=back 2122=back
1894 2123
1895=cut 2124=cut
1896 2125
1897min_parallel 8; 2126min_parallel 8;

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