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Revision 1.117 by root, Sat Oct 6 14:05:19 2007 UTC vs.
Revision 1.166 by root, Thu Nov 12 00:01:52 2009 UTC

… …
26 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
27 27
28 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
29 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
30 30
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
31 # AnyEvent integration 34 # EV integration
32 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!"; 35 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
33 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34 36
35 # Event integration 37 # Event integration
36 Event->io (fd => IO::AIO::poll_fileno, 38 Event->io (fd => IO::AIO::poll_fileno,
37 poll => 'r', 39 poll => 'r',
38 cb => \&IO::AIO::poll_cb); 40 cb => \&IO::AIO::poll_cb);
… …
50 \&IO::AIO::poll_cb); 52 \&IO::AIO::poll_cb);
51 53
52=head1 DESCRIPTION 54=head1 DESCRIPTION
53 55
54This module implements asynchronous I/O using whatever means your 56This module implements asynchronous I/O using whatever means your
55operating system supports. 57operating system supports. It is implemented as an interface to C<libeio>
58(L<http://software.schmorp.de/pkg/libeio.html>).
56 59
57Asynchronous means that operations that can normally block your program 60Asynchronous means that operations that can normally block your program
58(e.g. reading from disk) will be done asynchronously: the operation 61(e.g. reading from disk) will be done asynchronously: the operation
59will still block, but you can do something else in the meantime. This 62will still block, but you can do something else in the meantime. This
60is extremely useful for programs that need to stay interactive even 63is extremely useful for programs that need to stay interactive even
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64on a RAID volume or over NFS when you do a number of stat operations 67on a RAID volume or over NFS when you do a number of stat operations
65concurrently. 68concurrently.
66 69
67While most of this works on all types of file descriptors (for 70While most of this works on all types of file descriptors (for
68example sockets), using these functions on file descriptors that 71example sockets), using these functions on file descriptors that
69support nonblocking operation (again, sockets, pipes etc.) is very 72support nonblocking operation (again, sockets, pipes etc.) is
70inefficient. Use an event loop for that (such as the L<Event|Event> 73very inefficient. Use an event loop for that (such as the L<EV>
71module): IO::AIO will naturally fit into such an event loop itself. 74module): IO::AIO will naturally fit into such an event loop itself.
72 75
73In this version, a number of threads are started that execute your 76In this version, a number of threads are started that execute your
74requests and signal their completion. You don't need thread support 77requests and signal their completion. You don't need thread support
75in perl, and the threads created by this module will not be visible 78in perl, and the threads created by this module will not be visible
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85yourself, always call C<poll_cb> from within the same thread, or never 88yourself, always call C<poll_cb> from within the same thread, or never
86call C<poll_cb> (or other C<aio_> functions) recursively. 89call C<poll_cb> (or other C<aio_> functions) recursively.
87 90
88=head2 EXAMPLE 91=head2 EXAMPLE
89 92
90This is a simple example that uses the Event module and loads 93This is a simple example that uses the EV module and loads
91F</etc/passwd> asynchronously: 94F</etc/passwd> asynchronously:
92 95
93 use Fcntl; 96 use Fcntl;
94 use Event; 97 use EV;
95 use IO::AIO; 98 use IO::AIO;
96 99
97 # register the IO::AIO callback with Event 100 # register the IO::AIO callback with EV
98 Event->io (fd => IO::AIO::poll_fileno, 101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
99 poll => 'r',
100 cb => \&IO::AIO::poll_cb);
101 102
102 # queue the request to open /etc/passwd 103 # queue the request to open /etc/passwd
103 aio_open "/etc/passwd", O_RDONLY, 0, sub { 104 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 my $fh = shift 105 my $fh = shift
105 or die "error while opening: $!"; 106 or die "error while opening: $!";
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117 118
118 # file contents now in $contents 119 # file contents now in $contents
119 print $contents; 120 print $contents;
120 121
121 # exit event loop and program 122 # exit event loop and program
122 Event::unloop; 123 EV::unloop;
123 }; 124 };
124 }; 125 };
125 126
126 # possibly queue up other requests, or open GUI windows, 127 # possibly queue up other requests, or open GUI windows,
127 # check for sockets etc. etc. 128 # check for sockets etc. etc.
128 129
129 # process events as long as there are some: 130 # process events as long as there are some:
130 Event::loop; 131 EV::loop;
131 132
132=head1 REQUEST ANATOMY AND LIFETIME 133=head1 REQUEST ANATOMY AND LIFETIME
133 134
134Every C<aio_*> function creates a request. which is a C data structure not 135Every C<aio_*> function creates a request. which is a C data structure not
135directly visible to Perl. 136directly visible to Perl.
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185 186
186package IO::AIO; 187package IO::AIO;
187 188
188use Carp (); 189use Carp ();
189 190
190no warnings; 191use common::sense;
191use strict 'vars';
192 192
193use base 'Exporter'; 193use base 'Exporter';
194 194
195BEGIN { 195BEGIN {
196 our $VERSION = '2.51'; 196 our $VERSION = '3.3';
197 197
198 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 198 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
199 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 199 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
200 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link 200 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
201 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
202 aio_rename aio_link aio_move aio_copy aio_group
201 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir 203 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
202 aio_chown aio_chmod aio_utime aio_truncate); 204 aio_chmod aio_utime aio_truncate);
205
203 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); 206 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
204 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 207 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
205 min_parallel max_parallel max_idle 208 min_parallel max_parallel max_idle
206 nreqs nready npending nthreads 209 nreqs nready npending nthreads
207 max_poll_time max_poll_reqs); 210 max_poll_time max_poll_reqs
211 sendfile fadvise);
212
213 push @AIO_REQ, qw(aio_busy); # not exported
208 214
209 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 215 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
210 216
211 require XSLoader; 217 require XSLoader;
212 XSLoader::load ("IO::AIO", $VERSION); 218 XSLoader::load ("IO::AIO", $VERSION);
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219All the C<aio_*> calls are more or less thin wrappers around the syscall 225All the C<aio_*> calls are more or less thin wrappers around the syscall
220with the same name (sans C<aio_>). The arguments are similar or identical, 226with the same name (sans C<aio_>). The arguments are similar or identical,
221and they all accept an additional (and optional) C<$callback> argument 227and they all accept an additional (and optional) C<$callback> argument
222which must be a code reference. This code reference will get called with 228which must be a code reference. This code reference will get called with
223the syscall return code (e.g. most syscalls return C<-1> on error, unlike 229the syscall return code (e.g. most syscalls return C<-1> on error, unlike
224perl, which usually delivers "false") as it's sole argument when the given 230perl, which usually delivers "false") as its sole argument after the given
225syscall has been executed asynchronously. 231syscall has been executed asynchronously.
226 232
227All functions expecting a filehandle keep a copy of the filehandle 233All functions expecting a filehandle keep a copy of the filehandle
228internally until the request has finished. 234internally until the request has finished.
229 235
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243your pathnames to the locale (or other) encoding in effect in the user 249your pathnames to the locale (or other) encoding in effect in the user
244environment, d) use Glib::filename_from_unicode on unicode filenames or e) 250environment, d) use Glib::filename_from_unicode on unicode filenames or e)
245use something else to ensure your scalar has the correct contents. 251use something else to ensure your scalar has the correct contents.
246 252
247This works, btw. independent of the internal UTF-8 bit, which IO::AIO 253This works, btw. independent of the internal UTF-8 bit, which IO::AIO
248handles correctly wether it is set or not. 254handles correctly whether it is set or not.
249 255
250=over 4 256=over 4
251 257
252=item $prev_pri = aioreq_pri [$pri] 258=item $prev_pri = aioreq_pri [$pri]
253 259
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316 322
317Asynchronously close a file and call the callback with the result 323Asynchronously close a file and call the callback with the result
318code. 324code.
319 325
320Unfortunately, you can't do this to perl. Perl I<insists> very strongly on 326Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
321closing the file descriptor associated with the filehandle itself. Here is 327closing the file descriptor associated with the filehandle itself.
322what aio_close will try:
323 328
324 1. dup()licate the fd 329Therefore, C<aio_close> will not close the filehandle - instead it will
325 2. asynchronously close() the duplicated fd 330use dup2 to overwrite the file descriptor with the write-end of a pipe
326 3. dup()licate the fd once more 331(the pipe fd will be created on demand and will be cached).
327 4. let perl close() the filehandle
328 5. asynchronously close the duplicated fd
329 332
330The idea is that the first close() flushes stuff to disk that closing an 333Or in other words: the file descriptor will be closed, but it will not be
331fd will flush, so when perl closes the fd, nothing much will need to be 334free for reuse until the perl filehandle is closed.
332flushed. The second async. close() will then flush stuff to disk that
333closing the last fd to the file will flush.
334
335Just FYI, SuSv3 has this to say on close:
336
337 All outstanding record locks owned by the process on the file
338 associated with the file descriptor shall be removed.
339
340 If fildes refers to a socket, close() shall cause the socket to be
341 destroyed. ... close() shall block for up to the current linger
342 interval until all data is transmitted.
343 [this actually sounds like a specification bug, but who knows]
344
345And at least Linux additionally actually flushes stuff on every close,
346even when the file itself is still open.
347
348Sounds enourmously inefficient and complicated? Yes... please show me how
349to nuke perl's fd out of existence...
350 335
351=cut 336=cut
352 337
353sub aio_close($;$) {
354 aio_block {
355 my ($fh, $cb) = @_;
356
357 my $pri = aioreq_pri;
358 my $grp = aio_group $cb;
359
360 my $fd = fileno $fh;
361
362 defined $fd or Carp::croak "aio_close called with fd-less filehandle";
363
364 # if the dups fail we will simply get EBADF
365 my $fd2 = _dup $fd;
366 aioreq_pri $pri;
367 add $grp _aio_close $fd2, sub {
368 my $fd2 = _dup $fd;
369 close $fh;
370 aioreq_pri $pri;
371 add $grp _aio_close $fd2, sub {
372 $grp->result ($_[0]);
373 };
374 };
375
376 $grp
377 }
378}
379
380
381=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 338=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
382 339
383=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 340=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
384 341
385Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 342Reads or writes C<$length> bytes from or to the specified C<$fh> and
386into the scalar given by C<$data> and offset C<$dataoffset> and calls the 343C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
387callback without the actual number of bytes read (or -1 on error, just 344and calls the callback without the actual number of bytes read (or -1 on
388like the syscall). 345error, just like the syscall).
346
347C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
348offset plus the actual number of bytes read.
389 349
390If C<$offset> is undefined, then the current file descriptor offset will 350If C<$offset> is undefined, then the current file descriptor offset will
391be used (and updated), otherwise the file descriptor offset will not be 351be used (and updated), otherwise the file descriptor offset will not be
392changed by these calls. 352changed by these calls.
393 353
394If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 354If C<$length> is undefined in C<aio_write>, use the remaining length of
355C<$data>.
395 356
396If C<$dataoffset> is less than zero, it will be counted from the end of 357If C<$dataoffset> is less than zero, it will be counted from the end of
397C<$data>. 358C<$data>.
398 359
399The C<$data> scalar I<MUST NOT> be modified in any way while the request 360The C<$data> scalar I<MUST NOT> be modified in any way while the request
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571 532
572Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 533Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
573directory (i.e. opendir + readdir + closedir). The entries will not be 534directory (i.e. opendir + readdir + closedir). The entries will not be
574sorted, and will B<NOT> include the C<.> and C<..> entries. 535sorted, and will B<NOT> include the C<.> and C<..> entries.
575 536
576The callback a single argument which is either C<undef> or an array-ref 537The callback is passed a single argument which is either C<undef> or an
577with the filenames. 538array-ref with the filenames.
539
540
541=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
542
543Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
544behaviour and output format. In case of an error, C<$entries> will be
545C<undef>.
546
547The flags are a combination of the following constants, ORed together (the
548flags will also be passed to the callback, possibly modified):
549
550=over 4
551
552=item IO::AIO::READDIR_DENTS
553
554When this flag is off, then the callback gets an arrayref with of names
555only (as with C<aio_readdir>), otherwise it gets an arrayref with
556C<[$name, $type, $inode]> arrayrefs, each describing a single directory
557entry in more detail.
558
559C<$name> is the name of the entry.
560
561C<$type> is one of the C<IO::AIO::DT_xxx> constants:
562
563C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
564C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
565C<IO::AIO::DT_WHT>.
566
567C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
568know, you have to run stat yourself. Also, for speed reasons, the C<$type>
569scalars are read-only: you can not modify them.
570
571C<$inode> is the inode number (which might not be exact on systems with 64
572bit inode numbers and 32 bit perls). This field has unspecified content on
573systems that do not deliver the inode information.
574
575=item IO::AIO::READDIR_DIRS_FIRST
576
577When this flag is set, then the names will be returned in an order where
578likely directories come first. This is useful when you need to quickly
579find directories, or you want to find all directories while avoiding to
580stat() each entry.
581
582If the system returns type information in readdir, then this is used
583to find directories directly. Otherwise, likely directories are files
584beginning with ".", or otherwise files with no dots, of which files with
585short names are tried first.
586
587=item IO::AIO::READDIR_STAT_ORDER
588
589When this flag is set, then the names will be returned in an order
590suitable for stat()'ing each one. That is, when you plan to stat()
591all files in the given directory, then the returned order will likely
592be fastest.
593
594If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
595the likely dirs come first, resulting in a less optimal stat order.
596
597=item IO::AIO::READDIR_FOUND_UNKNOWN
598
599This flag should not be set when calling C<aio_readdirx>. Instead, it
600is being set by C<aio_readdirx>, when any of the C<$type>'s found were
601C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
602C<$type>'s are known, which can be used to speed up some algorithms.
603
604=back
578 605
579 606
580=item aio_load $path, $data, $callback->($status) 607=item aio_load $path, $data, $callback->($status)
581 608
582This is a composite request that tries to fully load the given file into 609This is a composite request that tries to fully load the given file into
583memory. Status is the same as with aio_read. 610memory. Status is the same as with aio_read.
584 611
585=cut 612=cut
586 613
587sub aio_load($$;$) { 614sub aio_load($$;$) {
588 aio_block {
589 my ($path, undef, $cb) = @_; 615 my ($path, undef, $cb) = @_;
590 my $data = \$_[1]; 616 my $data = \$_[1];
591 617
592 my $pri = aioreq_pri; 618 my $pri = aioreq_pri;
593 my $grp = aio_group $cb; 619 my $grp = aio_group $cb;
620
621 aioreq_pri $pri;
622 add $grp aio_open $path, O_RDONLY, 0, sub {
623 my $fh = shift
624 or return $grp->result (-1);
594 625
595 aioreq_pri $pri; 626 aioreq_pri $pri;
596 add $grp aio_open $path, O_RDONLY, 0, sub {
597 my $fh = shift
598 or return $grp->result (-1);
599
600 aioreq_pri $pri;
601 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { 627 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
602 $grp->result ($_[0]); 628 $grp->result ($_[0]);
603 };
604 }; 629 };
605
606 $grp
607 } 630 };
631
632 $grp
608} 633}
609 634
610=item aio_copy $srcpath, $dstpath, $callback->($status) 635=item aio_copy $srcpath, $dstpath, $callback->($status)
611 636
612Try to copy the I<file> (directories not supported as either source or 637Try to copy the I<file> (directories not supported as either source or
613destination) from C<$srcpath> to C<$dstpath> and call the callback with 638destination) from C<$srcpath> to C<$dstpath> and call the callback with
614the C<0> (error) or C<-1> ok. 639a status of C<0> (ok) or C<-1> (error, see C<$!>).
615 640
616This is a composite request that it creates the destination file with 641This is a composite request that creates the destination file with
617mode 0200 and copies the contents of the source file into it using 642mode 0200 and copies the contents of the source file into it using
618C<aio_sendfile>, followed by restoring atime, mtime, access mode and 643C<aio_sendfile>, followed by restoring atime, mtime, access mode and
619uid/gid, in that order. 644uid/gid, in that order.
620 645
621If an error occurs, the partial destination file will be unlinked, if 646If an error occurs, the partial destination file will be unlinked, if
… …
623errors are being ignored. 648errors are being ignored.
624 649
625=cut 650=cut
626 651
627sub aio_copy($$;$) { 652sub aio_copy($$;$) {
628 aio_block {
629 my ($src, $dst, $cb) = @_; 653 my ($src, $dst, $cb) = @_;
630 654
631 my $pri = aioreq_pri; 655 my $pri = aioreq_pri;
632 my $grp = aio_group $cb; 656 my $grp = aio_group $cb;
633 657
634 aioreq_pri $pri; 658 aioreq_pri $pri;
635 add $grp aio_open $src, O_RDONLY, 0, sub { 659 add $grp aio_open $src, O_RDONLY, 0, sub {
636 if (my $src_fh = $_[0]) { 660 if (my $src_fh = $_[0]) {
637 my @stat = stat $src_fh; 661 my @stat = stat $src_fh; # hmm, might block over nfs?
638 662
639 aioreq_pri $pri; 663 aioreq_pri $pri;
640 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 664 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
641 if (my $dst_fh = $_[0]) { 665 if (my $dst_fh = $_[0]) {
642 aioreq_pri $pri; 666 aioreq_pri $pri;
643 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 667 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
644 if ($_[0] == $stat[7]) { 668 if ($_[0] == $stat[7]) {
645 $grp->result (0); 669 $grp->result (0);
646 close $src_fh; 670 close $src_fh;
647 671
648 # those should not normally block. should. should.
649 utime $stat[8], $stat[9], $dst;
650 chmod $stat[2] & 07777, $dst_fh;
651 chown $stat[4], $stat[5], $dst_fh;
652 close $dst_fh;
653 } else { 672 my $ch = sub {
654 $grp->result (-1);
655 close $src_fh;
656 close $dst_fh;
657
658 aioreq $pri; 673 aioreq_pri $pri;
674 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
675 aioreq_pri $pri;
676 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
677 aioreq_pri $pri;
659 add $grp aio_unlink $dst; 678 add $grp aio_close $dst_fh;
679 }
680 };
660 } 681 };
682
683 aioreq_pri $pri;
684 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
685 if ($_[0] < 0 && $! == ENOSYS) {
686 aioreq_pri $pri;
687 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
688 } else {
689 $ch->();
690 }
691 };
692 } else {
693 $grp->result (-1);
694 close $src_fh;
695 close $dst_fh;
696
697 aioreq $pri;
698 add $grp aio_unlink $dst;
661 }; 699 }
662 } else {
663 $grp->result (-1);
664 } 700 };
701 } else {
702 $grp->result (-1);
665 }, 703 }
666
667 } else {
668 $grp->result (-1);
669 } 704 },
705
706 } else {
707 $grp->result (-1);
670 }; 708 }
671
672 $grp
673 } 709 };
710
711 $grp
674} 712}
675 713
676=item aio_move $srcpath, $dstpath, $callback->($status) 714=item aio_move $srcpath, $dstpath, $callback->($status)
677 715
678Try to move the I<file> (directories not supported as either source or 716Try to move the I<file> (directories not supported as either source or
679destination) from C<$srcpath> to C<$dstpath> and call the callback with 717destination) from C<$srcpath> to C<$dstpath> and call the callback with
680the C<0> (error) or C<-1> ok. 718a status of C<0> (ok) or C<-1> (error, see C<$!>).
681 719
682This is a composite request that tries to rename(2) the file first. If 720This is a composite request that tries to rename(2) the file first; if
683rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 721rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
684that is successful, unlinking the C<$srcpath>. 722that is successful, unlinks the C<$srcpath>.
685 723
686=cut 724=cut
687 725
688sub aio_move($$;$) { 726sub aio_move($$;$) {
689 aio_block {
690 my ($src, $dst, $cb) = @_; 727 my ($src, $dst, $cb) = @_;
691 728
692 my $pri = aioreq_pri; 729 my $pri = aioreq_pri;
693 my $grp = aio_group $cb; 730 my $grp = aio_group $cb;
694 731
695 aioreq_pri $pri; 732 aioreq_pri $pri;
696 add $grp aio_rename $src, $dst, sub { 733 add $grp aio_rename $src, $dst, sub {
697 if ($_[0] && $! == EXDEV) { 734 if ($_[0] && $! == EXDEV) {
698 aioreq_pri $pri; 735 aioreq_pri $pri;
699 add $grp aio_copy $src, $dst, sub { 736 add $grp aio_copy $src, $dst, sub {
700 $grp->result ($_[0]);
701
702 if (!$_[0]) {
703 aioreq_pri $pri;
704 add $grp aio_unlink $src;
705 }
706 };
707 } else {
708 $grp->result ($_[0]); 737 $grp->result ($_[0]);
738
739 if (!$_[0]) {
740 aioreq_pri $pri;
741 add $grp aio_unlink $src;
742 }
709 } 743 };
744 } else {
745 $grp->result ($_[0]);
710 }; 746 }
711
712 $grp
713 } 747 };
748
749 $grp
714} 750}
715 751
716=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 752=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
717 753
718Scans a directory (similar to C<aio_readdir>) but additionally tries to 754Scans a directory (similar to C<aio_readdir>) but additionally tries to
… …
738 774
739Implementation notes. 775Implementation notes.
740 776
741The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 777The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
742 778
779If readdir returns file type information, then this is used directly to
780find directories.
781
743After reading the directory, the modification time, size etc. of the 782Otherwise, after reading the directory, the modification time, size etc.
744directory before and after the readdir is checked, and if they match (and 783of the directory before and after the readdir is checked, and if they
745isn't the current time), the link count will be used to decide how many 784match (and isn't the current time), the link count will be used to decide
746entries are directories (if >= 2). Otherwise, no knowledge of the number 785how many entries are directories (if >= 2). Otherwise, no knowledge of the
747of subdirectories will be assumed. 786number of subdirectories will be assumed.
748 787
749Then entries will be sorted into likely directories (everything without 788Then entries will be sorted into likely directories a non-initial dot
750a non-initial dot currently) and likely non-directories (everything 789currently) and likely non-directories (see C<aio_readdirx>). Then every
751else). Then every entry plus an appended C</.> will be C<stat>'ed, 790entry plus an appended C</.> will be C<stat>'ed, likely directories first,
752likely directories first. If that succeeds, it assumes that the entry 791in order of their inode numbers. If that succeeds, it assumes that the
753is a directory or a symlink to directory (which will be checked 792entry is a directory or a symlink to directory (which will be checked
754seperately). This is often faster than stat'ing the entry itself because 793seperately). This is often faster than stat'ing the entry itself because
755filesystems might detect the type of the entry without reading the inode 794filesystems might detect the type of the entry without reading the inode
756data (e.g. ext2fs filetype feature). 795data (e.g. ext2fs filetype feature), even on systems that cannot return
796the filetype information on readdir.
757 797
758If the known number of directories (link count - 2) has been reached, the 798If the known number of directories (link count - 2) has been reached, the
759rest of the entries is assumed to be non-directories. 799rest of the entries is assumed to be non-directories.
760 800
761This only works with certainty on POSIX (= UNIX) filesystems, which 801This only works with certainty on POSIX (= UNIX) filesystems, which
… …
766directory counting heuristic. 806directory counting heuristic.
767 807
768=cut 808=cut
769 809
770sub aio_scandir($$;$) { 810sub aio_scandir($$;$) {
771 aio_block {
772 my ($path, $maxreq, $cb) = @_; 811 my ($path, $maxreq, $cb) = @_;
773 812
774 my $pri = aioreq_pri; 813 my $pri = aioreq_pri;
775 814
776 my $grp = aio_group $cb; 815 my $grp = aio_group $cb;
777 816
778 $maxreq = 4 if $maxreq <= 0; 817 $maxreq = 4 if $maxreq <= 0;
779 818
780 # stat once 819 # stat once
820 aioreq_pri $pri;
821 add $grp aio_stat $path, sub {
822 return $grp->result () if $_[0];
823 my $now = time;
824 my $hash1 = join ":", (stat _)[0,1,3,7,9];
825
826 # read the directory entries
781 aioreq_pri $pri; 827 aioreq_pri $pri;
782 add $grp aio_stat $path, sub { 828 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
829 my $entries = shift
783 return $grp->result () if $_[0]; 830 or return $grp->result ();
784 my $now = time;
785 my $hash1 = join ":", (stat _)[0,1,3,7,9];
786 831
787 # read the directory entries 832 # stat the dir another time
788 aioreq_pri $pri; 833 aioreq_pri $pri;
789 add $grp aio_readdir $path, sub {
790 my $entries = shift
791 or return $grp->result ();
792
793 # stat the dir another time
794 aioreq_pri $pri;
795 add $grp aio_stat $path, sub { 834 add $grp aio_stat $path, sub {
796 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 835 my $hash2 = join ":", (stat _)[0,1,3,7,9];
797 836
798 my $ndirs; 837 my $ndirs;
799 838
800 # take the slow route if anything looks fishy 839 # take the slow route if anything looks fishy
801 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 840 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
802 $ndirs = -1; 841 $ndirs = -1;
803 } else { 842 } else {
804 # if nlink == 2, we are finished 843 # if nlink == 2, we are finished
805 # on non-posix-fs's, we rely on nlink < 2 844 # for non-posix-fs's, we rely on nlink < 2
806 $ndirs = (stat _)[3] - 2 845 $ndirs = (stat _)[3] - 2
807 or return $grp->result ([], $entries); 846 or return $grp->result ([], $entries);
808 } 847 }
809 848
810 # sort into likely dirs and likely nondirs
811 # dirs == files without ".", short entries first
812 $entries = [map $_->[0],
813 sort { $b->[1] cmp $a->[1] }
814 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
815 @$entries];
816
817 my (@dirs, @nondirs); 849 my (@dirs, @nondirs);
818 850
819 my $statgrp = add $grp aio_group sub { 851 my $statgrp = add $grp aio_group sub {
820 $grp->result (\@dirs, \@nondirs); 852 $grp->result (\@dirs, \@nondirs);
821 }; 853 };
822 854
823 limit $statgrp $maxreq; 855 limit $statgrp $maxreq;
824 feed $statgrp sub { 856 feed $statgrp sub {
825 return unless @$entries; 857 return unless @$entries;
826 my $entry = pop @$entries; 858 my $entry = shift @$entries;
827 859
828 aioreq_pri $pri; 860 aioreq_pri $pri;
829 add $statgrp aio_stat "$path/$entry/.", sub { 861 add $statgrp aio_stat "$path/$entry/.", sub {
830 if ($_[0] < 0) { 862 if ($_[0] < 0) {
831 push @nondirs, $entry; 863 push @nondirs, $entry;
832 } else { 864 } else {
833 # need to check for real directory 865 # need to check for real directory
834 aioreq_pri $pri; 866 aioreq_pri $pri;
835 add $statgrp aio_lstat "$path/$entry", sub { 867 add $statgrp aio_lstat "$path/$entry", sub {
836 if (-d _) { 868 if (-d _) {
837 push @dirs, $entry; 869 push @dirs, $entry;
838 870
839 unless (--$ndirs) { 871 unless (--$ndirs) {
840 push @nondirs, @$entries; 872 push @nondirs, @$entries;
841 feed $statgrp; 873 feed $statgrp;
842 }
843 } else {
844 push @nondirs, $entry;
845 } 874 }
875 } else {
876 push @nondirs, $entry;
846 } 877 }
847 } 878 }
848 }; 879 }
849 }; 880 };
850 }; 881 };
851 }; 882 };
852 }; 883 };
853
854 $grp
855 } 884 };
885
886 $grp
856} 887}
857 888
858=item aio_rmtree $path, $callback->($status) 889=item aio_rmtree $path, $callback->($status)
859 890
860Delete a directory tree starting (and including) C<$path>, return the 891Delete a directory tree starting (and including) C<$path>, return the
… …
864 895
865=cut 896=cut
866 897
867sub aio_rmtree; 898sub aio_rmtree;
868sub aio_rmtree($;$) { 899sub aio_rmtree($;$) {
869 aio_block {
870 my ($path, $cb) = @_; 900 my ($path, $cb) = @_;
871 901
872 my $pri = aioreq_pri; 902 my $pri = aioreq_pri;
873 my $grp = aio_group $cb; 903 my $grp = aio_group $cb;
874 904
875 aioreq_pri $pri; 905 aioreq_pri $pri;
876 add $grp aio_scandir $path, 0, sub { 906 add $grp aio_scandir $path, 0, sub {
877 my ($dirs, $nondirs) = @_; 907 my ($dirs, $nondirs) = @_;
878 908
879 my $dirgrp = aio_group sub { 909 my $dirgrp = aio_group sub {
880 add $grp aio_rmdir $path, sub { 910 add $grp aio_rmdir $path, sub {
881 $grp->result ($_[0]); 911 $grp->result ($_[0]);
882 };
883 }; 912 };
884
885 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
886 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
887
888 add $grp $dirgrp;
889 }; 913 };
890 914
891 $grp 915 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
916 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
917
918 add $grp $dirgrp;
892 } 919 };
920
921 $grp
893} 922}
923
924=item aio_sync $callback->($status)
925
926Asynchronously call sync and call the callback when finished.
894 927
895=item aio_fsync $fh, $callback->($status) 928=item aio_fsync $fh, $callback->($status)
896 929
897Asynchronously call fsync on the given filehandle and call the callback 930Asynchronously call fsync on the given filehandle and call the callback
898with the fsync result code. 931with the fsync result code.
… …
902Asynchronously call fdatasync on the given filehandle and call the 935Asynchronously call fdatasync on the given filehandle and call the
903callback with the fdatasync result code. 936callback with the fdatasync result code.
904 937
905If this call isn't available because your OS lacks it or it couldn't be 938If this call isn't available because your OS lacks it or it couldn't be
906detected, it will be emulated by calling C<fsync> instead. 939detected, it will be emulated by calling C<fsync> instead.
940
941=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
942
943Sync the data portion of the file specified by C<$offset> and C<$length>
944to disk (but NOT the metadata), by calling the Linux-specific
945sync_file_range call. If sync_file_range is not available or it returns
946ENOSYS, then fdatasync or fsync is being substituted.
947
948C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
949C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
950C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
951manpage for details.
952
953=item aio_pathsync $path, $callback->($status)
954
955This request tries to open, fsync and close the given path. This is a
956composite request intended to sync directories after directory operations
957(E.g. rename). This might not work on all operating systems or have any
958specific effect, but usually it makes sure that directory changes get
959written to disc. It works for anything that can be opened for read-only,
960not just directories.
961
962Future versions of this function might fall back to other methods when
963C<fsync> on the directory fails (such as calling C<sync>).
964
965Passes C<0> when everything went ok, and C<-1> on error.
966
967=cut
968
969sub aio_pathsync($;$) {
970 my ($path, $cb) = @_;
971
972 my $pri = aioreq_pri;
973 my $grp = aio_group $cb;
974
975 aioreq_pri $pri;
976 add $grp aio_open $path, O_RDONLY, 0, sub {
977 my ($fh) = @_;
978 if ($fh) {
979 aioreq_pri $pri;
980 add $grp aio_fsync $fh, sub {
981 $grp->result ($_[0]);
982
983 aioreq_pri $pri;
984 add $grp aio_close $fh;
985 };
986 } else {
987 $grp->result (-1);
988 }
989 };
990
991 $grp
992}
907 993
908=item aio_group $callback->(...) 994=item aio_group $callback->(...)
909 995
910This is a very special aio request: Instead of doing something, it is a 996This is a very special aio request: Instead of doing something, it is a
911container for other aio requests, which is useful if you want to bundle 997container for other aio requests, which is useful if you want to bundle
… …
961=item cancel $req 1047=item cancel $req
962 1048
963Cancels the request, if possible. Has the effect of skipping execution 1049Cancels the request, if possible. Has the effect of skipping execution
964when entering the B<execute> state and skipping calling the callback when 1050when entering the B<execute> state and skipping calling the callback when
965entering the the B<result> state, but will leave the request otherwise 1051entering the the B<result> state, but will leave the request otherwise
966untouched. That means that requests that currently execute will not be 1052untouched (with the exception of readdir). That means that requests that
967stopped and resources held by the request will not be freed prematurely. 1053currently execute will not be stopped and resources held by the request
1054will not be freed prematurely.
968 1055
969=item cb $req $callback->(...) 1056=item cb $req $callback->(...)
970 1057
971Replace (or simply set) the callback registered to the request. 1058Replace (or simply set) the callback registered to the request.
972 1059
… …
1023Their lifetime, simplified, looks like this: when they are empty, they 1110Their lifetime, simplified, looks like this: when they are empty, they
1024will finish very quickly. If they contain only requests that are in the 1111will finish very quickly. If they contain only requests that are in the
1025C<done> state, they will also finish. Otherwise they will continue to 1112C<done> state, they will also finish. Otherwise they will continue to
1026exist. 1113exist.
1027 1114
1028That means after creating a group you have some time to add requests. And 1115That means after creating a group you have some time to add requests
1029in the callbacks of those requests, you can add further requests to the 1116(precisely before the callback has been invoked, which is only done within
1030group. And only when all those requests have finished will the the group 1117the C<poll_cb>). And in the callbacks of those requests, you can add
1031itself finish. 1118further requests to the group. And only when all those requests have
1119finished will the the group itself finish.
1032 1120
1033=over 4 1121=over 4
1034 1122
1035=item add $grp ... 1123=item add $grp ...
1036 1124
… …
1048itself. Useful when you queued a lot of events but got a result early. 1136itself. Useful when you queued a lot of events but got a result early.
1049 1137
1050=item $grp->result (...) 1138=item $grp->result (...)
1051 1139
1052Set the result value(s) that will be passed to the group callback when all 1140Set the result value(s) that will be passed to the group callback when all
1053subrequests have finished and set thre groups errno to the current value 1141subrequests have finished and set the groups errno to the current value
1054of errno (just like calling C<errno> without an error number). By default, 1142of errno (just like calling C<errno> without an error number). By default,
1055no argument will be passed and errno is zero. 1143no argument will be passed and errno is zero.
1056 1144
1057=item $grp->errno ([$errno]) 1145=item $grp->errno ([$errno])
1058 1146
… …
1069=item feed $grp $callback->($grp) 1157=item feed $grp $callback->($grp)
1070 1158
1071Sets a feeder/generator on this group: every group can have an attached 1159Sets a feeder/generator on this group: every group can have an attached
1072generator that generates requests if idle. The idea behind this is that, 1160generator that generates requests if idle. The idea behind this is that,
1073although you could just queue as many requests as you want in a group, 1161although you could just queue as many requests as you want in a group,
1074this might starve other requests for a potentially long time. For 1162this might starve other requests for a potentially long time. For example,
1075example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1163C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1076requests, delaying any later requests for a long time. 1164delaying any later requests for a long time.
1077 1165
1078To avoid this, and allow incremental generation of requests, you can 1166To avoid this, and allow incremental generation of requests, you can
1079instead a group and set a feeder on it that generates those requests. The 1167instead a group and set a feeder on it that generates those requests. The
1080feed callback will be called whenever there are few enough (see C<limit>, 1168feed callback will be called whenever there are few enough (see C<limit>,
1081below) requests active in the group itself and is expected to queue more 1169below) requests active in the group itself and is expected to queue more
… …
1085not impose any limits). 1173not impose any limits).
1086 1174
1087If the feed does not queue more requests when called, it will be 1175If the feed does not queue more requests when called, it will be
1088automatically removed from the group. 1176automatically removed from the group.
1089 1177
1090If the feed limit is C<0>, it will be set to C<2> automatically. 1178If the feed limit is C<0> when this method is called, it will be set to
1179C<2> automatically.
1091 1180
1092Example: 1181Example:
1093 1182
1094 # stat all files in @files, but only ever use four aio requests concurrently: 1183 # stat all files in @files, but only ever use four aio requests concurrently:
1095 1184
… …
1107Sets the feeder limit for the group: The feeder will be called whenever 1196Sets the feeder limit for the group: The feeder will be called whenever
1108the group contains less than this many requests. 1197the group contains less than this many requests.
1109 1198
1110Setting the limit to C<0> will pause the feeding process. 1199Setting the limit to C<0> will pause the feeding process.
1111 1200
1201The default value for the limit is C<0>, but note that setting a feeder
1202automatically bumps it up to C<2>.
1203
1112=back 1204=back
1113 1205
1114=head2 SUPPORT FUNCTIONS 1206=head2 SUPPORT FUNCTIONS
1115 1207
1116=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1208=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1118=over 4 1210=over 4
1119 1211
1120=item $fileno = IO::AIO::poll_fileno 1212=item $fileno = IO::AIO::poll_fileno
1121 1213
1122Return the I<request result pipe file descriptor>. This filehandle must be 1214Return the I<request result pipe file descriptor>. This filehandle must be
1123polled for reading by some mechanism outside this module (e.g. Event or 1215polled for reading by some mechanism outside this module (e.g. EV, Glib,
1124select, see below or the SYNOPSIS). If the pipe becomes readable you have 1216select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1125to call C<poll_cb> to check the results. 1217you have to call C<poll_cb> to check the results.
1126 1218
1127See C<poll_cb> for an example. 1219See C<poll_cb> for an example.
1128 1220
1129=item IO::AIO::poll_cb 1221=item IO::AIO::poll_cb
1130 1222
1131Process some outstanding events on the result pipe. You have to call this 1223Process some outstanding events on the result pipe. You have to call this
1132regularly. Returns the number of events processed. Returns immediately 1224regularly. Returns C<0> if all events could be processed, or C<-1> if it
1225returned earlier for whatever reason. Returns immediately when no events
1133when no events are outstanding. The amount of events processed depends on 1226are outstanding. The amount of events processed depends on the settings of
1134the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1227C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1135 1228
1136If not all requests were processed for whatever reason, the filehandle 1229If not all requests were processed for whatever reason, the filehandle
1137will still be ready when C<poll_cb> returns. 1230will still be ready when C<poll_cb> returns, so normally you don't have to
1231do anything special to have it called later.
1138 1232
1139Example: Install an Event watcher that automatically calls 1233Example: Install an Event watcher that automatically calls
1140IO::AIO::poll_cb with high priority: 1234IO::AIO::poll_cb with high priority (more examples can be found in the
1235SYNOPSIS section, at the top of this document):
1141 1236
1142 Event->io (fd => IO::AIO::poll_fileno, 1237 Event->io (fd => IO::AIO::poll_fileno,
1143 poll => 'r', async => 1, 1238 poll => 'r', async => 1,
1144 cb => \&IO::AIO::poll_cb); 1239 cb => \&IO::AIO::poll_cb);
1145 1240
… …
1256 1351
1257The default is probably ok in most situations, especially if thread 1352The default is probably ok in most situations, especially if thread
1258creation is fast. If thread creation is very slow on your system you might 1353creation is fast. If thread creation is very slow on your system you might
1259want to use larger values. 1354want to use larger values.
1260 1355
1261=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1356=item IO::AIO::max_outstanding $maxreqs
1262 1357
1263This is a very bad function to use in interactive programs because it 1358This is a very bad function to use in interactive programs because it
1264blocks, and a bad way to reduce concurrency because it is inexact: Better 1359blocks, and a bad way to reduce concurrency because it is inexact: Better
1265use an C<aio_group> together with a feed callback. 1360use an C<aio_group> together with a feed callback.
1266 1361
… …
1271 1366
1272The default value is very large, so there is no practical limit on the 1367The default value is very large, so there is no practical limit on the
1273number of outstanding requests. 1368number of outstanding requests.
1274 1369
1275You can still queue as many requests as you want. Therefore, 1370You can still queue as many requests as you want. Therefore,
1276C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1371C<max_outstanding> is mainly useful in simple scripts (with low values) or
1277as a stop gap to shield against fatal memory overflow (with large values). 1372as a stop gap to shield against fatal memory overflow (with large values).
1278 1373
1279=back 1374=back
1280 1375
1281=head3 STATISTICAL INFORMATION 1376=head3 STATISTICAL INFORMATION
… …
1299 1394
1300=item IO::AIO::npending 1395=item IO::AIO::npending
1301 1396
1302Returns the number of requests currently in the pending state (executed, 1397Returns the number of requests currently in the pending state (executed,
1303but not yet processed by poll_cb). 1398but not yet processed by poll_cb).
1399
1400=back
1401
1402=head3 MISCELLANEOUS FUNCTIONS
1403
1404IO::AIO implements some functions that might be useful, but are not
1405asynchronous.
1406
1407=over 4
1408
1409=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1410
1411Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1412but is blocking (this makes most sense if you know the input data is
1413likely cached already and the output filehandle is set to non-blocking
1414operations).
1415
1416Returns the number of bytes copied, or C<-1> on error.
1417
1418=item IO::AIO::fadvise $fh, $offset, $len, $advice
1419
1420Simply calls the C<posix_fadvise> function (see it's
1421manpage for details). The following advice constants are
1422avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1423C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1424C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1425
1426On systems that do not implement C<posix_fadvise>, this function returns
1427ENOSYS, otherwise the return value of C<posix_fadvise>.
1304 1428
1305=back 1429=back
1306 1430
1307=cut 1431=cut
1308 1432
… …
1351 1475
1352Known bugs will be fixed in the next release. 1476Known bugs will be fixed in the next release.
1353 1477
1354=head1 SEE ALSO 1478=head1 SEE ALSO
1355 1479
1356L<Coro::AIO>. 1480L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1481more natural syntax.
1357 1482
1358=head1 AUTHOR 1483=head1 AUTHOR
1359 1484
1360 Marc Lehmann <schmorp@schmorp.de> 1485 Marc Lehmann <schmorp@schmorp.de>
1361 http://home.schmorp.de/ 1486 http://home.schmorp.de/

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