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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.207 by root, Mon Jul 25 16:50:33 2011 UTC vs.
Revision 1.211 by root, Tue Sep 27 12:10:29 2011 UTC

… …
179 aio_pathsync aio_readahead 179 aio_pathsync aio_readahead
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
185 aio_wd);
185 186
186 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
187 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
188 min_parallel max_parallel max_idle idle_timeout 189 min_parallel max_parallel max_idle idle_timeout
189 nreqs nready npending nthreads 190 nreqs nready npending nthreads
… …
205 206
206This section simply lists the prototypes of the most important functions 207This section simply lists the prototypes of the most important functions
207for quick reference. See the following sections for function-by-function 208for quick reference. See the following sections for function-by-function
208documentation. 209documentation.
209 210
211 aio_wd $pathname, $callback->($wd)
210 aio_open $pathname, $flags, $mode, $callback->($fh) 212 aio_open $pathname, $flags, $mode, $callback->($fh)
211 aio_close $fh, $callback->($status) 213 aio_close $fh, $callback->($status)
212 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
214 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
… …
219 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
220 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 222 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
221 aio_truncate $fh_or_path, $offset, $callback->($status) 223 aio_truncate $fh_or_path, $offset, $callback->($status)
222 aio_chmod $fh_or_path, $mode, $callback->($status) 224 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_unlink $pathname, $callback->($status) 225 aio_unlink $pathname, $callback->($status)
224 aio_mknod $path, $mode, $dev, $callback->($status) 226 aio_mknod $pathname, $mode, $dev, $callback->($status)
225 aio_link $srcpath, $dstpath, $callback->($status) 227 aio_link $srcpath, $dstpath, $callback->($status)
226 aio_symlink $srcpath, $dstpath, $callback->($status) 228 aio_symlink $srcpath, $dstpath, $callback->($status)
227 aio_readlink $path, $callback->($link) 229 aio_readlink $pathname, $callback->($link)
228 aio_realpath $path, $callback->($link) 230 aio_realpath $pathname, $callback->($link)
229 aio_rename $srcpath, $dstpath, $callback->($status) 231 aio_rename $srcpath, $dstpath, $callback->($status)
230 aio_mkdir $pathname, $mode, $callback->($status) 232 aio_mkdir $pathname, $mode, $callback->($status)
231 aio_rmdir $pathname, $callback->($status) 233 aio_rmdir $pathname, $callback->($status)
232 aio_readdir $pathname, $callback->($entries) 234 aio_readdir $pathname, $callback->($entries)
233 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 235 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
234 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
235 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
236 aio_load $path, $data, $callback->($status) 238 aio_load $pathname, $data, $callback->($status)
237 aio_copy $srcpath, $dstpath, $callback->($status) 239 aio_copy $srcpath, $dstpath, $callback->($status)
238 aio_move $srcpath, $dstpath, $callback->($status) 240 aio_move $srcpath, $dstpath, $callback->($status)
239 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
240 aio_rmtree $path, $callback->($status) 242 aio_rmtree $pathname, $callback->($status)
241 aio_sync $callback->($status) 243 aio_sync $callback->($status)
242 aio_syncfs $fh, $callback->($status) 244 aio_syncfs $fh, $callback->($status)
243 aio_fsync $fh, $callback->($status) 245 aio_fsync $fh, $callback->($status)
244 aio_fdatasync $fh, $callback->($status) 246 aio_fdatasync $fh, $callback->($status)
245 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
246 aio_pathsync $path, $callback->($status) 248 aio_pathsync $pathname, $callback->($status)
247 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
248 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
249 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
250 aio_mlockall $flags, $callback->($status) 252 aio_mlockall $flags, $callback->($status)
251 aio_group $callback->(...) 253 aio_group $callback->(...)
… …
290internally until the request has finished. 292internally until the request has finished.
291 293
292All 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
293further manipulation of those requests while they are in-flight. 295further manipulation of those requests while they are in-flight.
294 296
295The pathnames you pass to these routines I<must> be absolute and 297The pathnames you pass to these routines I<should> be absolute. The
296encoded 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
297request is being executed, the current working directory could have 299current working directory could have changed. Alternatively, you can make
298changed. Alternatively, you can make sure that you never change the 300sure that you never change the current working directory anywhere in
299current working directory anywhere in the program and then use relative 301the program and then use relative paths. Lastly, you can take advantage
300paths. 302of IO::AIOs working directory abstraction - see the description of the
303C<IO::AIO::WD> class later in this document.
301 304
302To 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
303in filenames you got from outside (command line, readdir etc.) without 306in filenames you got from outside (command line, readdir etc.) without
304tinkering, 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
305your 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
… …
614 617
615Asynchronously unlink (delete) a file and call the callback with the 618Asynchronously unlink (delete) a file and call the callback with the
616result code. 619result code.
617 620
618 621
619=item aio_mknod $path, $mode, $dev, $callback->($status) 622=item aio_mknod $pathname, $mode, $dev, $callback->($status)
620 623
621[EXPERIMENTAL] 624[EXPERIMENTAL]
622 625
623Asynchronously create a device node (or fifo). See mknod(2). 626Asynchronously create a device node (or fifo). See mknod(2).
624 627
625The only (POSIX-) portable way of calling this function is: 628The only (POSIX-) portable way of calling this function is:
626 629
627 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 630 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
628 631
629See C<aio_stat> for info about some potentially helpful extra constants 632See C<aio_stat> for info about some potentially helpful extra constants
630and functions. 633and functions.
631 634
632=item aio_link $srcpath, $dstpath, $callback->($status) 635=item aio_link $srcpath, $dstpath, $callback->($status)
… …
639 642
640Asynchronously 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
641the path C<$dstpath> and call the callback with the result code. 644the path C<$dstpath> and call the callback with the result code.
642 645
643 646
644=item aio_readlink $path, $callback->($link) 647=item aio_readlink $pathname, $callback->($link)
645 648
646Asynchronously read the symlink specified by C<$path> and pass it to 649Asynchronously read the symlink specified by C<$path> and pass it to
647the 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
648callback. 651callback.
649 652
650 653
651=item aio_realpath $path, $callback->($path) 654=item aio_realpath $pathname, $callback->($path)
652 655
653Asynchronously make the path absolute and resolve any symlinks in 656Asynchronously make the path absolute and resolve any symlinks in
654C<$path>. The resulting path only consists of directories (Same as 657C<$path>. The resulting path only consists of directories (Same as
655L<Cwd::realpath>). 658L<Cwd::realpath>).
656 659
… …
751C<$type>'s are known, which can be used to speed up some algorithms. 754C<$type>'s are known, which can be used to speed up some algorithms.
752 755
753=back 756=back
754 757
755 758
756=item aio_load $path, $data, $callback->($status) 759=item aio_load $pathname, $data, $callback->($status)
757 760
758This 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
759memory. Status is the same as with aio_read. 762memory. Status is the same as with aio_read.
760 763
761=cut 764=cut
… …
896 }; 899 };
897 900
898 $grp 901 $grp
899} 902}
900 903
901=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 904=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
902 905
903Scans a directory (similar to C<aio_readdir>) but additionally tries to 906Scans a directory (similar to C<aio_readdir>) but additionally tries to
904efficiently separate the entries of directory C<$path> into two sets of 907efficiently separate the entries of directory C<$path> into two sets of
905names, directories you can recurse into (directories), and ones you cannot 908names, directories you can recurse into (directories), and ones you cannot
906recurse into (everything else, including symlinks to directories). 909recurse into (everything else, including symlinks to directories).
… …
963 966
964 my $grp = aio_group $cb; 967 my $grp = aio_group $cb;
965 968
966 $maxreq = 4 if $maxreq <= 0; 969 $maxreq = 4 if $maxreq <= 0;
967 970
968 # stat once 971 # get a wd object
972
969 aioreq_pri $pri; 973 aioreq_pri $pri;
970 add $grp aio_stat $path, sub { 974 add $grp aio_wd $path, sub {
971 return $grp->result () if $_[0]; 975 my $wd = [shift, "."];
972 my $now = time;
973 my $hash1 = join ":", (stat _)[0,1,3,7,9];
974 976
975 # read the directory entries 977 # stat once
976 aioreq_pri $pri; 978 aioreq_pri $pri;
977 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 979 add $grp aio_stat $wd, sub {
978 my $entries = shift
979 or return $grp->result (); 980 return $grp->result () if $_[0];
981 my $now = time;
982 my $hash1 = join ":", (stat _)[0,1,3,7,9];
980 983
981 # stat the dir another time 984 # read the directory entries
982 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;
983 add $grp aio_stat $path, sub { 992 add $grp aio_stat $wd, sub {
984 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 993 my $hash2 = join ":", (stat _)[0,1,3,7,9];
985 994
986 my $ndirs; 995 my $ndirs;
987 996
988 # take the slow route if anything looks fishy 997 # take the slow route if anything looks fishy
989 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 998 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
990 $ndirs = -1; 999 $ndirs = -1;
991 } else { 1000 } else {
992 # if nlink == 2, we are finished 1001 # if nlink == 2, we are finished
993 # for non-posix-fs's, we rely on nlink < 2 1002 # for non-posix-fs's, we rely on nlink < 2
994 $ndirs = (stat _)[3] - 2 1003 $ndirs = (stat _)[3] - 2
995 or return $grp->result ([], $entries); 1004 or return $grp->result ([], $entries);
996 } 1005 }
997 1006
998 my (@dirs, @nondirs); 1007 my (@dirs, @nondirs);
999 1008
1000 my $statgrp = add $grp aio_group sub { 1009 my $statgrp = add $grp aio_group sub {
1001 $grp->result (\@dirs, \@nondirs); 1010 $grp->result (\@dirs, \@nondirs);
1002 }; 1011 };
1003 1012
1004 limit $statgrp $maxreq; 1013 limit $statgrp $maxreq;
1005 feed $statgrp sub { 1014 feed $statgrp sub {
1006 return unless @$entries; 1015 return unless @$entries;
1007 my $entry = shift @$entries; 1016 my $entry = shift @$entries;
1008 1017
1009 aioreq_pri $pri; 1018 aioreq_pri $pri;
1019 $wd->[1] = "$entry/.";
1010 add $statgrp aio_stat "$path/$entry/.", sub { 1020 add $statgrp aio_stat $wd, sub {
1011 if ($_[0] < 0) { 1021 if ($_[0] < 0) {
1012 push @nondirs, $entry; 1022 push @nondirs, $entry;
1013 } else { 1023 } else {
1014 # need to check for real directory 1024 # need to check for real directory
1015 aioreq_pri $pri; 1025 aioreq_pri $pri;
1026 $wd->[1] = $entry;
1016 add $statgrp aio_lstat "$path/$entry", sub { 1027 add $statgrp aio_lstat $wd, sub {
1017 if (-d _) { 1028 if (-d _) {
1018 push @dirs, $entry; 1029 push @dirs, $entry;
1019 1030
1020 unless (--$ndirs) { 1031 unless (--$ndirs) {
1021 push @nondirs, @$entries; 1032 push @nondirs, @$entries;
1022 feed $statgrp; 1033 feed $statgrp;
1034 }
1035 } else {
1036 push @nondirs, $entry;
1023 } 1037 }
1024 } else {
1025 push @nondirs, $entry;
1026 } 1038 }
1027 } 1039 }
1028 } 1040 };
1029 }; 1041 };
1030 }; 1042 };
1031 }; 1043 };
1032 }; 1044 };
1033 }; 1045 };
1034 1046
1035 $grp 1047 $grp
1036} 1048}
1037 1049
1038=item aio_rmtree $path, $callback->($status) 1050=item aio_rmtree $pathname, $callback->($status)
1039 1051
1040Delete a directory tree starting (and including) C<$path>, return the 1052Delete a directory tree starting (and including) C<$path>, return the
1041status 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
1042uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1054uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1043everything else. 1055everything else.
… …
1104C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1116C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1105C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1117C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1106C<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
1107manpage for details. 1119manpage for details.
1108 1120
1109=item aio_pathsync $path, $callback->($status) 1121=item aio_pathsync $pathname, $callback->($status)
1110 1122
1111This 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
1112composite request intended to sync directories after directory operations 1124composite request intended to sync directories after directory operations
1113(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
1114specific effect, but usually it makes sure that directory changes get 1126specific effect, but usually it makes sure that directory changes get
… …
1257immense (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
1258except to put your application under artificial I/O pressure. 1270except to put your application under artificial I/O pressure.
1259 1271
1260=back 1272=back
1261 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
1262=head2 IO::AIO::REQ CLASS 1384=head2 IO::AIO::REQ CLASS
1263 1385
1264All 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
1265called in non-void context. 1387called in non-void context.
1266 1388
… …
1383 1505
1384Sets 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
1385generator that generates requests if idle. The idea behind this is that, 1507generator that generates requests if idle. The idea behind this is that,
1386although 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,
1387this might starve other requests for a potentially long time. For example, 1509this might starve other requests for a potentially long time. For example,
1388C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1510C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1389delaying any later requests for a long time. 1511requests, delaying any later requests for a long time.
1390 1512
1391To avoid this, and allow incremental generation of requests, you can 1513To avoid this, and allow incremental generation of requests, you can
1392instead 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
1393feed 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>,
1394below) 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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