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Revision 1.212 by root, Thu Sep 29 22:42:15 2011 UTC vs.
Revision 1.253 by root, Thu Jun 25 13:34:28 2015 UTC

68=head2 EXAMPLE 68=head2 EXAMPLE
69 69
70This is a simple example that uses the EV module and loads 70This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
72 72
73 use Fcntl;
74 use EV; 73 use EV;
75 use IO::AIO; 74 use IO::AIO;
76 75
77 # register the IO::AIO callback with EV 76 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 77 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
168use common::sense; 167use common::sense;
169 168
170use base 'Exporter'; 169use base 'Exporter';
171 170
172BEGIN { 171BEGIN {
173 our $VERSION = '4.0'; 172 our $VERSION = 4.32;
174 173
175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 174 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 175 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 176 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate 177 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
179 aio_pathsync aio_readahead 178 aio_pathsync aio_readahead aio_fiemap
180 aio_rename aio_link aio_move aio_copy aio_group 179 aio_rename aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 180 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 181 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 182 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 183 aio_statvfs
202 201
203=head1 FUNCTIONS 202=head1 FUNCTIONS
204 203
205=head2 QUICK OVERVIEW 204=head2 QUICK OVERVIEW
206 205
207This section simply lists the prototypes of the most important functions 206This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 207quick reference. See the following sections for function-by-function
209documentation. 208documentation.
210 209
211 aio_wd $pathname, $callback->($wd) 210 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 211 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 212 aio_close $fh, $callback->($status)
213 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 217 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 218 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 219 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 220 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 222 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
223 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 224 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 225 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
226 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 227 aio_unlink $pathname, $callback->($status)
226 aio_mknod $pathname, $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 $pathname, $callback->($link) 231 aio_readlink $pathname, $callback->($link)
230 aio_realpath $pathname, $callback->($link) 232 aio_realpath $pathname, $callback->($path)
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 $pathname, $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 $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $pathname, $callback->($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)
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 be called after 290which must be a code reference. This code reference will be called after
317correct contents. 321correct contents.
318 322
319This 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
320handles correctly whether it is set or not. 324handles correctly whether it is set or not.
321 325
326=head2 AIO REQUEST FUNCTIONS
327
322=over 4 328=over 4
323 329
324=item $prev_pri = aioreq_pri [$pri] 330=item $prev_pri = aioreq_pri [$pri]
325 331
326Returns the priority value that would be used for the next request and, if 332Returns the priority value that would be used for the next request and, if
355 361
356 362
357=item aio_open $pathname, $flags, $mode, $callback->($fh) 363=item aio_open $pathname, $flags, $mode, $callback->($fh)
358 364
359Asynchronously open or create a file and call the callback with a newly 365Asynchronously open or create a file and call the callback with a newly
360created filehandle for the file. 366created filehandle for the file (or C<undef> in case of an error).
361 367
362The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 368The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
363for an explanation. 369for an explanation.
364 370
365The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 371The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
407 413
408Or 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
409free for reuse until the perl filehandle is closed. 415free for reuse until the perl filehandle is closed.
410 416
411=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".
412 438
413=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 439=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
414 440
415=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 441=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
416 442
576 namemax => 255, 602 namemax => 255,
577 frsize => 1024, 603 frsize => 1024,
578 fsid => 1810 604 fsid => 1810
579 } 605 }
580 606
607Here is a (likely partial - send me updates!) list of fsid values used by
608Linux - it is safe to hardcode these when C<$^O> is C<linux>:
609
610 0x0000adf5 adfs
611 0x0000adff affs
612 0x5346414f afs
613 0x09041934 anon-inode filesystem
614 0x00000187 autofs
615 0x42465331 befs
616 0x1badface bfs
617 0x42494e4d binfmt_misc
618 0x9123683e btrfs
619 0x0027e0eb cgroupfs
620 0xff534d42 cifs
621 0x73757245 coda
622 0x012ff7b7 coh
623 0x28cd3d45 cramfs
624 0x453dcd28 cramfs-wend (wrong endianness)
625 0x64626720 debugfs
626 0x00001373 devfs
627 0x00001cd1 devpts
628 0x0000f15f ecryptfs
629 0x00414a53 efs
630 0x0000137d ext
631 0x0000ef53 ext2/ext3
632 0x0000ef51 ext2
633 0x00004006 fat
634 0x65735546 fuseblk
635 0x65735543 fusectl
636 0x0bad1dea futexfs
637 0x01161970 gfs2
638 0x47504653 gpfs
639 0x00004244 hfs
640 0xf995e849 hpfs
641 0x958458f6 hugetlbfs
642 0x2bad1dea inotifyfs
643 0x00009660 isofs
644 0x000072b6 jffs2
645 0x3153464a jfs
646 0x6b414653 k-afs
647 0x0bd00bd0 lustre
648 0x0000137f minix
649 0x0000138f minix 30 char names
650 0x00002468 minix v2
651 0x00002478 minix v2 30 char names
652 0x00004d5a minix v3
653 0x19800202 mqueue
654 0x00004d44 msdos
655 0x0000564c novell
656 0x00006969 nfs
657 0x6e667364 nfsd
658 0x00003434 nilfs
659 0x5346544e ntfs
660 0x00009fa1 openprom
661 0x7461636F ocfs2
662 0x00009fa0 proc
663 0x6165676c pstorefs
664 0x0000002f qnx4
665 0x858458f6 ramfs
666 0x52654973 reiserfs
667 0x00007275 romfs
668 0x67596969 rpc_pipefs
669 0x73636673 securityfs
670 0xf97cff8c selinux
671 0x0000517b smb
672 0x534f434b sockfs
673 0x73717368 squashfs
674 0x62656572 sysfs
675 0x012ff7b6 sysv2
676 0x012ff7b5 sysv4
677 0x01021994 tmpfs
678 0x15013346 udf
679 0x00011954 ufs
680 0x54190100 ufs byteswapped
681 0x00009fa2 usbdevfs
682 0x01021997 v9fs
683 0xa501fcf5 vxfs
684 0xabba1974 xenfs
685 0x012ff7b4 xenix
686 0x58465342 xfs
687 0x012fd16d xia
581 688
582=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 689=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
583 690
584Works like perl's C<utime> function (including the special case of $atime 691Works like perl's C<utime> function (including the special case of $atime
585and $mtime being undef). Fractional times are supported if the underlying 692and $mtime being undef). Fractional times are supported if the underlying
613=item aio_truncate $fh_or_path, $offset, $callback->($status) 720=item aio_truncate $fh_or_path, $offset, $callback->($status)
614 721
615Works like truncate(2) or ftruncate(2). 722Works like truncate(2) or ftruncate(2).
616 723
617 724
725=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
726
727Allocates or frees disk space according to the C<$mode> argument. See the
728linux C<fallocate> documentation for details.
729
730C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
731space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
732to deallocate a file range.
733
734IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
735(without leaving a hole) and C<FALLOC_FL_ZERO_RANGE>, to zero a range (see
736your L<fallocate(2)> manpage).
737
738The file system block size used by C<fallocate> is presumably the
739C<f_bsize> returned by C<statvfs>.
740
741If C<fallocate> isn't available or cannot be emulated (currently no
742emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
743
744
618=item aio_chmod $fh_or_path, $mode, $callback->($status) 745=item aio_chmod $fh_or_path, $mode, $callback->($status)
619 746
620Works like perl's C<chmod> function. 747Works like perl's C<chmod> function.
621 748
622 749
659 786
660 787
661=item aio_realpath $pathname, $callback->($path) 788=item aio_realpath $pathname, $callback->($path)
662 789
663Asynchronously make the path absolute and resolve any symlinks in 790Asynchronously make the path absolute and resolve any symlinks in
664C<$path>. The resulting path only consists of directories (Same as 791C<$path>. The resulting path only consists of directories (same as
665L<Cwd::realpath>). 792L<Cwd::realpath>).
666 793
667This request can be used to get the absolute path of the current working 794This request can be used to get the absolute path of the current working
668directory by passing it a path of F<.> (a single dot). 795directory by passing it a path of F<.> (a single dot).
669 796
670 797
671=item aio_rename $srcpath, $dstpath, $callback->($status) 798=item aio_rename $srcpath, $dstpath, $callback->($status)
672 799
673Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 800Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
674rename(2) and call the callback with the result code. 801rename(2) and call the callback with the result code.
802
803On systems that support the AIO::WD working directory abstraction
804natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
805of failing, C<rename> is called on the absolute path of C<$wd>.
675 806
676 807
677=item aio_mkdir $pathname, $mode, $callback->($status) 808=item aio_mkdir $pathname, $mode, $callback->($status)
678 809
679Asynchronously mkdir (create) a directory and call the callback with 810Asynchronously mkdir (create) a directory and call the callback with
683 814
684=item aio_rmdir $pathname, $callback->($status) 815=item aio_rmdir $pathname, $callback->($status)
685 816
686Asynchronously rmdir (delete) a directory and call the callback with the 817Asynchronously rmdir (delete) a directory and call the callback with the
687result code. 818result code.
819
820On systems that support the AIO::WD working directory abstraction
821natively, the case C<[$wd, "."]> is specialcased - instead of failing,
822C<rmdir> is called on the absolute path of C<$wd>.
688 823
689 824
690=item aio_readdir $pathname, $callback->($entries) 825=item aio_readdir $pathname, $callback->($entries)
691 826
692Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 827Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
1057} 1192}
1058 1193
1059=item aio_rmtree $pathname, $callback->($status) 1194=item aio_rmtree $pathname, $callback->($status)
1060 1195
1061Delete a directory tree starting (and including) C<$path>, return the 1196Delete a directory tree starting (and including) C<$path>, return the
1062status of the final C<rmdir> only. This is a composite request that 1197status of the final C<rmdir> only. This is a composite request that
1063uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1198uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1064everything else. 1199everything else.
1065 1200
1066=cut 1201=cut
1067 1202
1187 1322
1188This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1323This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1189scalars. 1324scalars.
1190 1325
1191It touches (reads or writes) all memory pages in the specified 1326It touches (reads or writes) all memory pages in the specified
1192range inside the scalar. All caveats and parameters are the same 1327range inside the scalar. All caveats and parameters are the same
1193as for C<aio_msync>, above, except for flags, which must be either 1328as for C<aio_msync>, above, except for flags, which must be either
1194C<0> (which reads all pages and ensures they are instantiated) or 1329C<0> (which reads all pages and ensures they are instantiated) or
1195C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1330C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1196writing an octet from it, which dirties the page). 1331writing an octet from it, which dirties the page).
1197 1332
1198=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1333=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1199 1334
1200This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1335This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1231documented under L<MISCELLANEOUS FUNCTIONS>. 1366documented under L<MISCELLANEOUS FUNCTIONS>.
1232 1367
1233Example: asynchronously lock all current and future pages into memory. 1368Example: asynchronously lock all current and future pages into memory.
1234 1369
1235 aio_mlockall IO::AIO::MCL_FUTURE; 1370 aio_mlockall IO::AIO::MCL_FUTURE;
1371
1372=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1373
1374Queries the extents of the given file (by calling the Linux C<FIEMAP>
1375ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1376the ioctl is not available on your OS, then this request will fail with
1377C<ENOSYS>.
1378
1379C<$start> is the starting offset to query extents for, C<$length> is the
1380size of the range to query - if it is C<undef>, then the whole file will
1381be queried.
1382
1383C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1384C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1385exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1386the data portion.
1387
1388C<$count> is the maximum number of extent records to return. If it is
1389C<undef>, then IO::AIO queries all extents of the range. As a very special
1390case, if it is C<0>, then the callback receives the number of extents
1391instead of the extents themselves (which is unreliable, see below).
1392
1393If an error occurs, the callback receives no arguments. The special
1394C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1395
1396Otherwise, the callback receives an array reference with extent
1397structures. Each extent structure is an array reference itself, with the
1398following members:
1399
1400 [$logical, $physical, $length, $flags]
1401
1402Flags is any combination of the following flag values (typically either C<0>
1403or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1404
1405C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1406C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1407C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1408C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1409C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1410C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1411
1412At the time of this writing (Linux 3.2), this requets is unreliable unless
1413C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1414it to return all extents of a range for files with large number of
1415extents. The code works around all these issues if C<$count> is undef.
1236 1416
1237=item aio_group $callback->(...) 1417=item aio_group $callback->(...)
1238 1418
1239This is a very special aio request: Instead of doing something, it is a 1419This is a very special aio request: Instead of doing something, it is a
1240container for other aio requests, which is useful if you want to bundle 1420container for other aio requests, which is useful if you want to bundle
1304object. This object stores the canonicalised, absolute version of the 1484object. This object stores the canonicalised, absolute version of the
1305path, and on systems that allow it, also a directory file descriptor. 1485path, and on systems that allow it, also a directory file descriptor.
1306 1486
1307Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> 1487Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1308or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD 1488or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1309object and a pathname instead. If the pathname is absolute, the 1489object and a pathname instead (or the IO::AIO::WD object alone, which
1490gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1310IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative 1491IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1311to that IO::AIO::WD object. 1492to that IO::AIO::WD object.
1312 1493
1313For example, to get a wd object for F</etc> and then stat F<passwd> 1494For example, to get a wd object for F</etc> and then stat F<passwd>
1314inside, you would write: 1495inside, you would write:
1315 1496
1323 aio_stat [$etcdir, "passwd"], sub { 1504 aio_stat [$etcdir, "passwd"], sub {
1324 # yay 1505 # yay
1325 }; 1506 };
1326 }; 1507 };
1327 1508
1509The fact that C<aio_wd> is a request and not a normal function shows that
1328This shows that creating an IO::AIO::WD object is itself a potentially 1510creating an IO::AIO::WD object is itself a potentially blocking operation,
1329blocking operation, which is why it is done asynchronously. 1511which is why it is done asynchronously.
1512
1513To stat the directory obtained with C<aio_wd> above, one could write
1514either of the following three request calls:
1515
1516 aio_lstat "/etc" , sub { ... # pathname as normal string
1517 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1518 aio_lstat $wd , sub { ... # shorthand for the previous
1330 1519
1331As with normal pathnames, IO::AIO keeps a copy of the working directory 1520As with normal pathnames, IO::AIO keeps a copy of the working directory
1332object and the pathname string, so you could write the following without 1521object and the pathname string, so you could write the following without
1333causing any issues due to C<$path> getting reused: 1522causing any issues due to C<$path> getting reused:
1334 1523
1347will still point to the original directory. Most functions accepting a 1536will still point to the original directory. Most functions accepting a
1348pathname will use the directory fd on newer systems, and the string on 1537pathname will use the directory fd on newer systems, and the string on
1349older systems. Some functions (such as realpath) will always rely on the 1538older systems. Some functions (such as realpath) will always rely on the
1350string form of the pathname. 1539string form of the pathname.
1351 1540
1352So this fucntionality is mainly useful to get some protection against 1541So this functionality is mainly useful to get some protection against
1353C<chdir>, to easily get an absolute path out of a relative path for future 1542C<chdir>, to easily get an absolute path out of a relative path for future
1354reference, and to speed up doing many operations in the same directory 1543reference, and to speed up doing many operations in the same directory
1355(e.g. when stat'ing all files in a directory). 1544(e.g. when stat'ing all files in a directory).
1356 1545
1357The following functions implement this working directory abstraction: 1546The following functions implement this working directory abstraction:
1370passing C<undef> as working directory component of a pathname fails the 1559passing C<undef> as working directory component of a pathname fails the
1371request with C<ENOENT>, there is often no need for error checking in the 1560request with C<ENOENT>, there is often no need for error checking in the
1372C<aio_wd> callback, as future requests using the value will fail in the 1561C<aio_wd> callback, as future requests using the value will fail in the
1373expected way. 1562expected way.
1374 1563
1375If this call isn't available because your OS lacks it or it couldn't be
1376detected, it will be emulated by calling C<fsync> instead.
1377
1378=item IO::AIO::CWD 1564=item IO::AIO::CWD
1379 1565
1380This is a compiletime constant (object) that represents the process 1566This is a compiletime constant (object) that represents the process
1381current working directory. 1567current working directory.
1382 1568
1383Specifying this object as working directory object for a pathname is as 1569Specifying this object as working directory object for a pathname is as if
1384if the pathname would be specified directly, without a directory object, 1570the pathname would be specified directly, without a directory object. For
1385e.g., these calls are functionally identical: 1571example, these calls are functionally identical:
1386 1572
1387 aio_stat "somefile", sub { ... }; 1573 aio_stat "somefile", sub { ... };
1388 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1574 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1389 1575
1390=back 1576=back
1391 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.
1392 1587
1393=head2 IO::AIO::REQ CLASS 1588=head2 IO::AIO::REQ CLASS
1394 1589
1395All 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
1396called in non-void context. 1591called in non-void context.
1574 1769
1575See C<poll_cb> for an example. 1770See C<poll_cb> for an example.
1576 1771
1577=item IO::AIO::poll_cb 1772=item IO::AIO::poll_cb
1578 1773
1579Process 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
1580this 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
1581were 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
1582reason. Returns immediately when no events are outstanding. The amount of 1780reason. Returns immediately when no events are outstanding. The amount
1583events 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>,
1584C<IO::AIO::max_poll_time>. 1782C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1585 1783
1586If not all requests were processed for whatever reason, the filehandle 1784If not all requests were processed for whatever reason, the poll file
1587will 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
1588do anything special to have it called later. 1786don't have to do anything special to have it called later.
1589 1787
1590Apart 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
1591ready, 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
1592a 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
1593available 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
1602 poll => 'r', async => 1, 1800 poll => 'r', async => 1,
1603 cb => \&IO::AIO::poll_cb); 1801 cb => \&IO::AIO::poll_cb);
1604 1802
1605=item IO::AIO::poll_wait 1803=item IO::AIO::poll_wait
1606 1804
1607If 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
1608phase, wait till the result filehandle becomes ready for reading (simply 1806requests are outstanding anymore.
1609does a C<select> on the filehandle. This is useful if you want to 1807
1610synchronously 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.
1611 1810
1612See C<nreqs> for an example. 1811See C<nreqs> for an example.
1613 1812
1614=item IO::AIO::poll 1813=item IO::AIO::poll
1615 1814
1736 1935
1737This is a very bad function to use in interactive programs because it 1936This is a very bad function to use in interactive programs because it
1738blocks, and a bad way to reduce concurrency because it is inexact: Better 1937blocks, and a bad way to reduce concurrency because it is inexact: Better
1739use an C<aio_group> together with a feed callback. 1938use an C<aio_group> together with a feed callback.
1740 1939
1741It's main use is in scripts without an event loop - when you want to stat 1940Its main use is in scripts without an event loop - when you want to stat
1742a lot of files, you can write somehting like this: 1941a lot of files, you can write somehting like this:
1743 1942
1744 IO::AIO::max_outstanding 32; 1943 IO::AIO::max_outstanding 32;
1745 1944
1746 for my $path (...) { 1945 for my $path (...) {
1786 1985
1787=back 1986=back
1788 1987
1789=head3 MISCELLANEOUS FUNCTIONS 1988=head3 MISCELLANEOUS FUNCTIONS
1790 1989
1791IO::AIO implements some functions that might be useful, but are not 1990IO::AIO implements some functions that are useful when you want to use
1792asynchronous. 1991some "Advanced I/O" function not available to in Perl, without going the
1992"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
1993counterpart.
1793 1994
1794=over 4 1995=over 4
1795 1996
1796=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 1997=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1797 1998
1834ENOSYS, otherwise the return value of C<mprotect>. 2035ENOSYS, otherwise the return value of C<mprotect>.
1835 2036
1836=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2037=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1837 2038
1838Memory-maps a file (or anonymous memory range) and attaches it to the 2039Memory-maps a file (or anonymous memory range) and attaches it to the
1839given C<$scalar>, which will act like a string scalar. 2040given C<$scalar>, which will act like a string scalar. Returns true on
2041success, and false otherwise.
1840 2042
1841The only operations allowed on the scalar are C<substr>/C<vec> that don't 2043The only operations allowed on the scalar are C<substr>/C<vec> that don't
1842change the string length, and most read-only operations such as copying it 2044change the string length, and most read-only operations such as copying it
1843or searching it with regexes and so on. 2045or searching it with regexes and so on.
1844 2046
1897Calls the C<munlockall> function. 2099Calls the C<munlockall> function.
1898 2100
1899On systems that do not implement C<munlockall>, this function returns 2101On systems that do not implement C<munlockall>, this function returns
1900ENOSYS, otherwise the return value of C<munlockall>. 2102ENOSYS, otherwise the return value of C<munlockall>.
1901 2103
2104=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2105
2106Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2107C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2108should be the file offset.
2109
2110C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2111silently corrupt the data in this case.
2112
2113The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2114C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2115C<IO::AIO::SPLICE_F_GIFT>.
2116
2117See the C<splice(2)> manpage for details.
2118
2119=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2120
2121Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2122description for C<IO::AIO::splice> above for details.
2123
2124=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2125
2126Attempts to query or change the pipe buffer size. Obviously works only
2127on pipes, and currently works only on GNU/Linux systems, and fails with
2128C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2129size on other systems, drop me a note.
2130
2131=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2132
2133This is a direct interface to the Linux L<pipe2(2)> system call. If
2134C<$flags> is missing or C<0>, then this should be the same as a call to
2135perl's built-in C<pipe> function and create a new pipe, and should work
2136everywhere.
2137
2138If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2139the given flags (Linux 2.6.27, glibc 2.9).
2140
2141On success, the read and write file handles are returned.
2142
2143On error, nothing will be returned. If the pipe2 syscall is missing and
2144C<$flags> is non-zero, fails with C<ENOSYS>.
2145
2146Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2147time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2148C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2149
1902=back 2150=back
1903 2151
1904=cut 2152=cut
1905 2153
1906min_parallel 8; 2154min_parallel 8;

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