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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 1.211 by root, Tue Sep 27 12:10:29 2011 UTC

… …
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_truncate $fh_or_path, $offset, $callback->($status) 223 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 224 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_unlink $pathname, $callback->($status) 225 aio_unlink $pathname, $callback->($status)
226 aio_mknod $path, $mode, $dev, $callback->($status) 226 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 227 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 228 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $path, $callback->($link) 229 aio_readlink $pathname, $callback->($link)
230 aio_realpath $path, $callback->($link) 230 aio_realpath $pathname, $callback->($link)
231 aio_rename $srcpath, $dstpath, $callback->($status) 231 aio_rename $srcpath, $dstpath, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 232 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 233 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 234 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 235 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
238 aio_load $path, $data, $callback->($status) 238 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 239 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 240 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $path, $callback->($status) 242 aio_rmtree $pathname, $callback->($status)
243 aio_sync $callback->($status) 243 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 244 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 245 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 246 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $path, $callback->($status) 248 aio_pathsync $pathname, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status) 252 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...) 253 aio_group $callback->(...)
… …
292internally until the request has finished. 292internally until the request has finished.
293 293
294All functions return request objects of type L<IO::AIO::REQ> that allow 294All functions return request objects of type L<IO::AIO::REQ> that allow
295further manipulation of those requests while they are in-flight. 295further manipulation of those requests while they are in-flight.
296 296
297The pathnames you pass to these routines I<must> be absolute and 297The 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 298reason for this is that at the time the request is being executed, the
299request is being executed, the current working directory could have 299current working directory could have changed. Alternatively, you can make
300changed. Alternatively, you can make sure that you never change the 300sure that you never change the current working directory anywhere in
301current working directory anywhere in the program and then use relative 301the program and then use relative paths. Lastly, you can take advantage
302paths. 302of IO::AIOs working directory abstraction - see the description of the
303C<IO::AIO::WD> class later in this document.
303 304
304To encode pathnames as octets, either make sure you either: a) always pass 305To encode pathnames as octets, either make sure you either: a) always pass
305in filenames you got from outside (command line, readdir etc.) without 306in 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 307tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
307your pathnames to the locale (or other) encoding in effect in the user 308your pathnames to the locale (or other) encoding in effect in the user
… …
616 617
617Asynchronously unlink (delete) a file and call the callback with the 618Asynchronously unlink (delete) a file and call the callback with the
618result code. 619result code.
619 620
620 621
621=item aio_mknod $path, $mode, $dev, $callback->($status) 622=item aio_mknod $pathname, $mode, $dev, $callback->($status)
622 623
623[EXPERIMENTAL] 624[EXPERIMENTAL]
624 625
625Asynchronously create a device node (or fifo). See mknod(2). 626Asynchronously create a device node (or fifo). See mknod(2).
626 627
627The only (POSIX-) portable way of calling this function is: 628The only (POSIX-) portable way of calling this function is:
628 629
629 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 630 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
630 631
631See C<aio_stat> for info about some potentially helpful extra constants 632See C<aio_stat> for info about some potentially helpful extra constants
632and functions. 633and functions.
633 634
634=item aio_link $srcpath, $dstpath, $callback->($status) 635=item aio_link $srcpath, $dstpath, $callback->($status)
… …
641 642
642Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 643Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
643the path C<$dstpath> and call the callback with the result code. 644the path C<$dstpath> and call the callback with the result code.
644 645
645 646
646=item aio_readlink $path, $callback->($link) 647=item aio_readlink $pathname, $callback->($link)
647 648
648Asynchronously read the symlink specified by C<$path> and pass it to 649Asynchronously read the symlink specified by C<$path> and pass it to
649the callback. If an error occurs, nothing or undef gets passed to the 650the callback. If an error occurs, nothing or undef gets passed to the
650callback. 651callback.
651 652
652 653
653=item aio_realpath $path, $callback->($path) 654=item aio_realpath $pathname, $callback->($path)
654 655
655Asynchronously make the path absolute and resolve any symlinks in 656Asynchronously make the path absolute and resolve any symlinks in
656C<$path>. The resulting path only consists of directories (Same as 657C<$path>. The resulting path only consists of directories (Same as
657L<Cwd::realpath>). 658L<Cwd::realpath>).
658 659
… …
753C<$type>'s are known, which can be used to speed up some algorithms. 754C<$type>'s are known, which can be used to speed up some algorithms.
754 755
755=back 756=back
756 757
757 758
758=item aio_load $path, $data, $callback->($status) 759=item aio_load $pathname, $data, $callback->($status)
759 760
760This is a composite request that tries to fully load the given file into 761This is a composite request that tries to fully load the given file into
761memory. Status is the same as with aio_read. 762memory. Status is the same as with aio_read.
762 763
763=cut 764=cut
… …
898 }; 899 };
899 900
900 $grp 901 $grp
901} 902}
902 903
903=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 904=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
904 905
905Scans a directory (similar to C<aio_readdir>) but additionally tries to 906Scans a directory (similar to C<aio_readdir>) but additionally tries to
906efficiently separate the entries of directory C<$path> into two sets of 907efficiently separate the entries of directory C<$path> into two sets of
907names, directories you can recurse into (directories), and ones you cannot 908names, directories you can recurse into (directories), and ones you cannot
908recurse into (everything else, including symlinks to directories). 909recurse into (everything else, including symlinks to directories).
… …
965 966
966 my $grp = aio_group $cb; 967 my $grp = aio_group $cb;
967 968
968 $maxreq = 4 if $maxreq <= 0; 969 $maxreq = 4 if $maxreq <= 0;
969 970
970 # stat once 971 # get a wd object
972
971 aioreq_pri $pri; 973 aioreq_pri $pri;
972 add $grp aio_stat $path, sub { 974 add $grp aio_wd $path, sub {
973 return $grp->result () if $_[0]; 975 my $wd = [shift, "."];
974 my $now = time;
975 my $hash1 = join ":", (stat _)[0,1,3,7,9];
976 976
977 # read the directory entries 977 # stat once
978 aioreq_pri $pri; 978 aioreq_pri $pri;
979 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 979 add $grp aio_stat $wd, sub {
980 my $entries = shift
981 or return $grp->result (); 980 return $grp->result () if $_[0];
981 my $now = time;
982 my $hash1 = join ":", (stat _)[0,1,3,7,9];
982 983
983 # stat the dir another time 984 # read the directory entries
984 aioreq_pri $pri; 985 aioreq_pri $pri;
986 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
987 my $entries = shift
988 or return $grp->result ();
989
990 # stat the dir another time
991 aioreq_pri $pri;
985 add $grp aio_stat $path, sub { 992 add $grp aio_stat $wd, sub {
986 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 993 my $hash2 = join ":", (stat _)[0,1,3,7,9];
987 994
988 my $ndirs; 995 my $ndirs;
989 996
990 # take the slow route if anything looks fishy 997 # take the slow route if anything looks fishy
991 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 998 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
992 $ndirs = -1; 999 $ndirs = -1;
993 } else { 1000 } else {
994 # if nlink == 2, we are finished 1001 # if nlink == 2, we are finished
995 # for non-posix-fs's, we rely on nlink < 2 1002 # for non-posix-fs's, we rely on nlink < 2
996 $ndirs = (stat _)[3] - 2 1003 $ndirs = (stat _)[3] - 2
997 or return $grp->result ([], $entries); 1004 or return $grp->result ([], $entries);
998 } 1005 }
999 1006
1000 my (@dirs, @nondirs); 1007 my (@dirs, @nondirs);
1001 1008
1002 my $statgrp = add $grp aio_group sub { 1009 my $statgrp = add $grp aio_group sub {
1003 $grp->result (\@dirs, \@nondirs); 1010 $grp->result (\@dirs, \@nondirs);
1004 }; 1011 };
1005 1012
1006 limit $statgrp $maxreq; 1013 limit $statgrp $maxreq;
1007 feed $statgrp sub { 1014 feed $statgrp sub {
1008 return unless @$entries; 1015 return unless @$entries;
1009 my $entry = shift @$entries; 1016 my $entry = shift @$entries;
1010 1017
1011 aioreq_pri $pri; 1018 aioreq_pri $pri;
1019 $wd->[1] = "$entry/.";
1012 add $statgrp aio_stat "$path/$entry/.", sub { 1020 add $statgrp aio_stat $wd, sub {
1013 if ($_[0] < 0) { 1021 if ($_[0] < 0) {
1014 push @nondirs, $entry; 1022 push @nondirs, $entry;
1015 } else { 1023 } else {
1016 # need to check for real directory 1024 # need to check for real directory
1017 aioreq_pri $pri; 1025 aioreq_pri $pri;
1026 $wd->[1] = $entry;
1018 add $statgrp aio_lstat "$path/$entry", sub { 1027 add $statgrp aio_lstat $wd, sub {
1019 if (-d _) { 1028 if (-d _) {
1020 push @dirs, $entry; 1029 push @dirs, $entry;
1021 1030
1022 unless (--$ndirs) { 1031 unless (--$ndirs) {
1023 push @nondirs, @$entries; 1032 push @nondirs, @$entries;
1024 feed $statgrp; 1033 feed $statgrp;
1034 }
1035 } else {
1036 push @nondirs, $entry;
1025 } 1037 }
1026 } else {
1027 push @nondirs, $entry;
1028 } 1038 }
1029 } 1039 }
1030 } 1040 };
1031 }; 1041 };
1032 }; 1042 };
1033 }; 1043 };
1034 }; 1044 };
1035 }; 1045 };
1036 1046
1037 $grp 1047 $grp
1038} 1048}
1039 1049
1040=item aio_rmtree $path, $callback->($status) 1050=item aio_rmtree $pathname, $callback->($status)
1041 1051
1042Delete a directory tree starting (and including) C<$path>, return the 1052Delete a directory tree starting (and including) C<$path>, return the
1043status of the final C<rmdir> only. This is a composite request that 1053status of the final C<rmdir> only. This is a composite request that
1044uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1054uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1045everything else. 1055everything else.
… …
1106C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1116C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1107C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1117C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1108C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range 1118C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1109manpage for details. 1119manpage for details.
1110 1120
1111=item aio_pathsync $path, $callback->($status) 1121=item aio_pathsync $pathname, $callback->($status)
1112 1122
1113This request tries to open, fsync and close the given path. This is a 1123This request tries to open, fsync and close the given path. This is a
1114composite request intended to sync directories after directory operations 1124composite request intended to sync directories after directory operations
1115(E.g. rename). This might not work on all operating systems or have any 1125(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 1126specific effect, but usually it makes sure that directory changes get
… …
1259immense (it blocks a thread for a long time) so do not use this function 1269immense (it blocks a thread for a long time) so do not use this function
1260except to put your application under artificial I/O pressure. 1270except to put your application under artificial I/O pressure.
1261 1271
1262=back 1272=back
1263 1273
1274
1275=head2 IO::AIO::WD - multiple working directories
1276
1277Your process only has one current working directory, which is used by all
1278threads. This makes it hard to use relative paths (some other component
1279could call C<chdir> at any time, and it is hard to control when the path
1280will be used by IO::AIO).
1281
1282One solution for this is to always use absolute paths. This usually works,
1283but can be quite slow (the kernel has to walk the whole path on every
1284access), and can also be a hassle to implement.
1285
1286Newer POSIX systems have a number of functions (openat, fdopendir,
1287futimensat and so on) that make it possible to specify working directories
1288per operation.
1289
1290For portability, and because the clowns who "designed", or shall I write,
1291perpetrated this new interface were obviously half-drunk, this abstraction
1292cannot be perfect, though.
1293
1294IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1295object. This object stores the canonicalised, absolute version of the
1296path, and on systems that allow it, also a directory file descriptor.
1297
1298Everywhere 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
1300object and a pathname instead. If the pathname is absolute, the
1301IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative
1302to that IO::AIO::WD object.
1303
1304For example, to get a wd object for F</etc> and then stat F<passwd>
1305inside, you would write:
1306
1307 aio_wd "/etc", sub {
1308 my $etcdir = shift;
1309
1310 # although $etcdir can be undef on error, there is generally no reason
1311 # to check for errors here, as aio_stat will fail with ENOENT
1312 # when $etcdir is undef.
1313
1314 aio_stat [$etcdir, "passwd"], sub {
1315 # yay
1316 };
1317 };
1318
1319This shows that creating an IO::AIO::WD object is itself a potentially
1320blocking operation, which is why it is done asynchronously.
1321
1322As with normal pathnames, IO::AIO keeps a copy of the working directory
1323object and the pathname string, so you could write the following without
1324causing any issues due to C<$path> getting reused:
1325
1326 my $path = [$wd, undef];
1327
1328 for my $name (qw(abc def ghi)) {
1329 $path->[1] = $name;
1330 aio_stat $path, sub {
1331 # ...
1332 };
1333 }
1334
1335There are some caveats: when directories get renamed (or deleted), the
1336pathname string doesn't change, so will point to the new directory (or
1337nowhere at all), while the directory fd, if available on the system,
1338will still point to the original directory. Most functions accepting a
1339pathname will use the directory fd on newer systems, and the string on
1340older systems. Some functions (such as realpath) will always rely on the
1341string form of the pathname.
1342
1343So this fucntionality is mainly useful to get some protection against
1344C<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
1346(e.g. when stat'ing all files in a directory).
1347
1348The following functions implement this working directory abstraction:
1349
1350=over 4
1351
1352=item aio_wd $pathname, $callback->($wd)
1353
1354Asynchonously canonicalise the given pathname and convert it to an
1355IO::AIO::WD object representing it. If possible and supported on the
1356system, also open a directory fd to speed up pathname resolution relative
1357to this working directory.
1358
1359If something goes wrong, then C<undef> is passwd to the callback instead
1360of a working directory object and C<$!> is set appropriately. Since
1361passing C<undef> as working directory component of a pathname fails the
1362request with C<ENOENT>, there is often no need for error checking in the
1363C<aio_wd> callback, as future requests using the value will fail in the
1364expected way.
1365
1366If this call isn't available because your OS lacks it or it couldn't be
1367detected, it will be emulated by calling C<fsync> instead.
1368
1369=item IO::AIO::CWD
1370
1371This is a compiletime constant (object) that represents the process
1372current working directory.
1373
1374Specifying this object as working directory object for a pathname is as
1375if the pathname would be specified directly, without a directory object,
1376e.g., these calls are functionally identical:
1377
1378 aio_stat "somefile", sub { ... };
1379 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1380
1381=back
1382
1383
1264=head2 IO::AIO::REQ CLASS 1384=head2 IO::AIO::REQ CLASS
1265 1385
1266All non-aggregate C<aio_*> functions return an object of this class when 1386All non-aggregate C<aio_*> functions return an object of this class when
1267called in non-void context. 1387called in non-void context.
1268 1388
… …
1385 1505
1386Sets a feeder/generator on this group: every group can have an attached 1506Sets a feeder/generator on this group: every group can have an attached
1387generator that generates requests if idle. The idea behind this is that, 1507generator 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, 1508although 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, 1509this might starve other requests for a potentially long time. For example,
1390C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1510C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1391delaying any later requests for a long time. 1511requests, delaying any later requests for a long time.
1392 1512
1393To avoid this, and allow incremental generation of requests, you can 1513To avoid this, and allow incremental generation of requests, you can
1394instead a group and set a feeder on it that generates those requests. The 1514instead 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>, 1515feed 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 1516below) requests active in the group itself and is expected to queue more

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