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Revision 1.23 by root, Mon Jan 22 15:59:52 2007 UTC vs.
Revision 1.29 by root, Wed Apr 16 16:45:30 2008 UTC

24 $req->cancel; # cancel request if still in queue 24 $req->cancel; # cancel request if still in queue
25 25
26 my $grp = aio_group sub { print "all stats done\n" }; 26 my $grp = aio_group sub { print "all stats done\n" };
27 add $grp aio_stat "..." for ...; 27 add $grp aio_stat "..." for ...;
28 28
29 # AnyEvent integration 29 # AnyEvent integration (EV, Event, Glib, Tk, urxvt, pureperl...)
30 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; 30 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
31 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb }); 31 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
32
33 # EV integration
34 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
32 35
33 # Event integration 36 # Event integration
34 Event->io (fd => IO::AIO::poll_fileno, 37 Event->io (fd => IO::AIO::poll_fileno,
35 poll => 'r', 38 poll => 'r',
36 cb => \&IO::AIO::poll_cb); 39 cb => \&IO::AIO::poll_cb);
61 faster on a RAID volume or over NFS when you do a number of stat 64 faster on a RAID volume or over NFS when you do a number of stat
62 operations concurrently. 65 operations concurrently.
63 66
64 While most of this works on all types of file descriptors (for example 67 While most of this works on all types of file descriptors (for example
65 sockets), using these functions on file descriptors that support 68 sockets), using these functions on file descriptors that support
66 nonblocking operation (again, sockets, pipes etc.) is very inefficient 69 nonblocking operation (again, sockets, pipes etc.) is very inefficient.
67 or might not work (aio_read fails on sockets/pipes/fifos). Use an event
68 loop for that (such as the Event module): IO::AIO will naturally fit 70 Use an event loop for that (such as the Event module): IO::AIO will
69 into such an event loop itself. 71 naturally fit into such an event loop itself.
70 72
71 In this version, a number of threads are started that execute your 73 In this version, a number of threads are started that execute your
72 requests and signal their completion. You don't need thread support in 74 requests and signal their completion. You don't need thread support in
73 perl, and the threads created by this module will not be visible to 75 perl, and the threads created by this module will not be visible to
74 perl. In the future, this module might make use of the native aio 76 perl. In the future, this module might make use of the native aio
76 not well-supported or restricted (GNU/Linux doesn't allow them on normal 78 not well-supported or restricted (GNU/Linux doesn't allow them on normal
77 files currently, for example), and they would only support aio_read and 79 files currently, for example), and they would only support aio_read and
78 aio_write, so the remaining functionality would have to be implemented 80 aio_write, so the remaining functionality would have to be implemented
79 using threads anyway. 81 using threads anyway.
80 82
81 Although the module will work with in the presence of other (Perl-) 83 Although the module will work in the presence of other (Perl-) threads,
82 threads, it is currently not reentrant in any way, so use appropriate 84 it is currently not reentrant in any way, so use appropriate locking
83 locking yourself, always call "poll_cb" from within the same thread, or 85 yourself, always call "poll_cb" from within the same thread, or never
84 never call "poll_cb" (or other "aio_" functions) recursively. 86 call "poll_cb" (or other "aio_" functions) recursively.
85 87
86 EXAMPLE 88 EXAMPLE
87 This is a simple example that uses the Event module and loads 89 This is a simple example that uses the Event module and loads
88 /etc/passwd asynchronously: 90 /etc/passwd asynchronously:
89 91
259 } 261 }
260 }; 262 };
261 263
262 aio_close $fh, $callback->($status) 264 aio_close $fh, $callback->($status)
263 Asynchronously close a file and call the callback with the result 265 Asynchronously close a file and call the callback with the result
264 code. *WARNING:* although accepted, you should not pass in a perl 266 code.
265 filehandle here, as perl will likely close the file descriptor
266 another time when the filehandle is destroyed. Normally, you can
267 safely call perls "close" or just let filehandles go out of scope.
268 267
269 This is supposed to be a bug in the API, so that might change. It's 268 Unfortunately, you can't do this to perl. Perl *insists* very
270 therefore best to avoid this function. 269 strongly on closing the file descriptor associated with the
270 filehandle itself.
271
272 Therefore, "aio_close" will not close the filehandle - instead it
273 will use dup2 to overwrite the file descriptor with the write-end of
274 a pipe (the pipe fd will be created on demand and will be cached).
275
276 Or in other words: the file descriptor will be closed, but it will
277 not be free for reuse until the perl filehandle is closed.
271 278
272 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 279 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
273 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 280 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
274 Reads or writes "length" bytes from the specified "fh" and "offset" 281 Reads or writes $length bytes from the specified $fh and $offset
275 into the scalar given by "data" and offset "dataoffset" and calls 282 into the scalar given by $data and offset $dataoffset and calls the
276 the callback without the actual number of bytes read (or -1 on 283 callback without the actual number of bytes read (or -1 on error,
277 error, just like the syscall). 284 just like the syscall).
285
286 If $offset is undefined, then the current file descriptor offset
287 will be used (and updated), otherwise the file descriptor offset
288 will not be changed by these calls.
289
290 If $length is undefined in "aio_write", use the remaining length of
291 $data.
292
293 If $dataoffset is less than zero, it will be counted from the end of
294 $data.
278 295
279 The $data scalar *MUST NOT* be modified in any way while the request 296 The $data scalar *MUST NOT* be modified in any way while the request
280 is outstanding. Modifying it can result in segfaults or WW3 (if the 297 is outstanding. Modifying it can result in segfaults or World War
281 necessary/optional hardware is installed). 298 III (if the necessary/optional hardware is installed).
282 299
283 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at 300 Example: Read 15 bytes at offset 7 into scalar $buffer, starting at
284 offset 0 within the scalar: 301 offset 0 within the scalar:
285 302
286 aio_read $fh, 7, 15, $buffer, 0, sub { 303 aio_read $fh, 7, 15, $buffer, 0, sub {
344 aio_stat "/etc/passwd", sub { 361 aio_stat "/etc/passwd", sub {
345 $_[0] and die "stat failed: $!"; 362 $_[0] and die "stat failed: $!";
346 print "size is ", -s _, "\n"; 363 print "size is ", -s _, "\n";
347 }; 364 };
348 365
366 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
367 Works like perl's "utime" function (including the special case of
368 $atime and $mtime being undef). Fractional times are supported if
369 the underlying syscalls support them.
370
371 When called with a pathname, uses utimes(2) if available, otherwise
372 utime(2). If called on a file descriptor, uses futimes(2) if
373 available, otherwise returns ENOSYS, so this is not portable.
374
375 Examples:
376
377 # set atime and mtime to current time (basically touch(1)):
378 aio_utime "path", undef, undef;
379 # set atime to current time and mtime to beginning of the epoch:
380 aio_utime "path", time, undef; # undef==0
381
382 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
383 Works like perl's "chown" function, except that "undef" for either
384 $uid or $gid is being interpreted as "do not change" (but -1 can
385 also be used).
386
387 Examples:
388
389 # same as "chown root path" in the shell:
390 aio_chown "path", 0, -1;
391 # same as above:
392 aio_chown "path", 0, undef;
393
394 aio_truncate $fh_or_path, $offset, $callback->($status)
395 Works like truncate(2) or ftruncate(2).
396
397 aio_chmod $fh_or_path, $mode, $callback->($status)
398 Works like perl's "chmod" function.
399
349 aio_unlink $pathname, $callback->($status) 400 aio_unlink $pathname, $callback->($status)
350 Asynchronously unlink (delete) a file and call the callback with the 401 Asynchronously unlink (delete) a file and call the callback with the
351 result code. 402 result code.
352 403
353 aio_mknod $path, $mode, $dev, $callback->($status) 404 aio_mknod $path, $mode, $dev, $callback->($status)
478 Delete a directory tree starting (and including) $path, return the 529 Delete a directory tree starting (and including) $path, return the
479 status of the final "rmdir" only. This is a composite request that 530 status of the final "rmdir" only. This is a composite request that
480 uses "aio_scandir" to recurse into and rmdir directories, and unlink 531 uses "aio_scandir" to recurse into and rmdir directories, and unlink
481 everything else. 532 everything else.
482 533
534 aio_sync $callback->($status)
535 Asynchronously call sync and call the callback when finished.
536
483 aio_fsync $fh, $callback->($status) 537 aio_fsync $fh, $callback->($status)
484 Asynchronously call fsync on the given filehandle and call the 538 Asynchronously call fsync on the given filehandle and call the
485 callback with the fsync result code. 539 callback with the fsync result code.
486 540
487 aio_fdatasync $fh, $callback->($status) 541 aio_fdatasync $fh, $callback->($status)
488 Asynchronously call fdatasync on the given filehandle and call the 542 Asynchronously call fdatasync on the given filehandle and call the
489 callback with the fdatasync result code. 543 callback with the fdatasync result code.
490 544
491 If this call isn't available because your OS lacks it or it couldn't 545 If this call isn't available because your OS lacks it or it couldn't
492 be detected, it will be emulated by calling "fsync" instead. 546 be detected, it will be emulated by calling "fsync" instead.
547
548 aio_pathsync $path, $callback->($status)
549 This request tries to open, fsync and close the given path. This is
550 a composite request intended tosync directories after directory
551 operations (E.g. rename). This might not work on all operating
552 systems or have any specific effect, but usually it makes sure that
553 directory changes get written to disc. It works for anything that
554 can be opened for read-only, not just directories.
555
556 Passes 0 when everything went ok, and -1 on error.
493 557
494 aio_group $callback->(...) 558 aio_group $callback->(...)
495 This is a very special aio request: Instead of doing something, it 559 This is a very special aio request: Instead of doing something, it
496 is a container for other aio requests, which is useful if you want 560 is a container for other aio requests, which is useful if you want
497 to bundle many requests into a single, composite, request with a 561 to bundle many requests into a single, composite, request with a
579 }; 643 };
580 644
581 This makes it very easy to create composite requests (see the source of 645 This makes it very easy to create composite requests (see the source of
582 "aio_move" for an application) that work and feel like simple requests. 646 "aio_move" for an application) that work and feel like simple requests.
583 647
584 * The IO::AIO::GRP objects will be cleaned up during calls to 648 * The IO::AIO::GRP objects will be cleaned up during calls to
585 "IO::AIO::poll_cb", just like any other request. 649 "IO::AIO::poll_cb", just like any other request.
650
586 * They can be canceled like any other request. Canceling will cancel not 651 * They can be canceled like any other request. Canceling will cancel
587 only the request itself, but also all requests it contains. 652 not only the request itself, but also all requests it contains.
653
588 * They can also can also be added to other IO::AIO::GRP objects. 654 * They can also can also be added to other IO::AIO::GRP objects.
655
589 * You must not add requests to a group from within the group callback 656 * You must not add requests to a group from within the group callback
590 (or any later time). 657 (or any later time).
591 658
592 Their lifetime, simplified, looks like this: when they are empty, they 659 Their lifetime, simplified, looks like this: when they are empty, they
593 will finish very quickly. If they contain only requests that are in the 660 will finish very quickly. If they contain only requests that are in the
594 "done" state, they will also finish. Otherwise they will continue to 661 "done" state, they will also finish. Otherwise they will continue to
595 exist. 662 exist.
612 request itself. Useful when you queued a lot of events but got a 679 request itself. Useful when you queued a lot of events but got a
613 result early. 680 result early.
614 681
615 $grp->result (...) 682 $grp->result (...)
616 Set the result value(s) that will be passed to the group callback 683 Set the result value(s) that will be passed to the group callback
617 when all subrequests have finished and set thre groups errno to the 684 when all subrequests have finished and set the groups errno to the
618 current value of errno (just like calling "errno" without an error 685 current value of errno (just like calling "errno" without an error
619 number). By default, no argument will be passed and errno is zero. 686 number). By default, no argument will be passed and errno is zero.
620 687
621 $grp->errno ([$errno]) 688 $grp->errno ([$errno])
622 Sets the group errno value to $errno, or the current value of errno 689 Sets the group errno value to $errno, or the current value of errno
808 $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 875 $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
809 This is a very bad function to use in interactive programs because 876 This is a very bad function to use in interactive programs because
810 it blocks, and a bad way to reduce concurrency because it is 877 it blocks, and a bad way to reduce concurrency because it is
811 inexact: Better use an "aio_group" together with a feed callback. 878 inexact: Better use an "aio_group" together with a feed callback.
812 879
813 Sets the maximum number of outstanding requests to $nreqs. If you to 880 Sets the maximum number of outstanding requests to $nreqs. If you do
814 queue up more than this number of requests, the next call to the 881 queue up more than this number of requests, the next call to the
815 "poll_cb" (and "poll_some" and other functions calling "poll_cb") 882 "poll_cb" (and "poll_some" and other functions calling "poll_cb")
816 function will block until the limit is no longer exceeded. 883 function will block until the limit is no longer exceeded.
817 884
818 The default value is very large, so there is no practical limit on 885 The default value is very large, so there is no practical limit on
864 bytes of memory. In addition, stat requests need a stat buffer (possibly 931 bytes of memory. In addition, stat requests need a stat buffer (possibly
865 a few hundred bytes), readdir requires a result buffer and so on. Perl 932 a few hundred bytes), readdir requires a result buffer and so on. Perl
866 scalars and other data passed into aio requests will also be locked and 933 scalars and other data passed into aio requests will also be locked and
867 will consume memory till the request has entered the done state. 934 will consume memory till the request has entered the done state.
868 935
869 This is now awfully much, so queuing lots of requests is not usually a 936 This is not awfully much, so queuing lots of requests is not usually a
870 problem. 937 problem.
871 938
872 Per-thread usage: 939 Per-thread usage:
873 940
874 In the execution phase, some aio requests require more memory for 941 In the execution phase, some aio requests require more memory for

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