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Revision 1.108 by root, Fri Jun 1 13:25:50 2007 UTC vs.
Revision 1.156 by root, Tue Jun 16 23:41:59 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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183 184
184=cut 185=cut
185 186
186package IO::AIO; 187package IO::AIO;
187 188
189use Carp ();
190
188no warnings; 191no warnings;
189use strict 'vars'; 192use strict 'vars';
190 193
191use base 'Exporter'; 194use base 'Exporter';
192 195
193BEGIN { 196BEGIN {
194 our $VERSION = '2.4'; 197 our $VERSION = '3.23';
195 198
196 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 199 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
197 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 200 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
198 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link 201 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
202 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
203 aio_rename aio_link aio_move aio_copy aio_group
199 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir 204 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
200 aio_chown aio_chmod aio_utime); 205 aio_chmod aio_utime aio_truncate);
206
201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); 207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203 min_parallel max_parallel max_idle 209 min_parallel max_parallel max_idle
204 nreqs nready npending nthreads 210 nreqs nready npending nthreads
205 max_poll_time max_poll_reqs); 211 max_poll_time max_poll_reqs);
212
213 push @AIO_REQ, qw(aio_busy); # not exported
206 214
207 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 215 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208 216
209 require XSLoader; 217 require XSLoader;
210 XSLoader::load ("IO::AIO", $VERSION); 218 XSLoader::load ("IO::AIO", $VERSION);
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217All the C<aio_*> calls are more or less thin wrappers around the syscall 225All the C<aio_*> calls are more or less thin wrappers around the syscall
218with the same name (sans C<aio_>). The arguments are similar or identical, 226with the same name (sans C<aio_>). The arguments are similar or identical,
219and they all accept an additional (and optional) C<$callback> argument 227and they all accept an additional (and optional) C<$callback> argument
220which 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
221the 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
222perl, which usually delivers "false") as it's sole argument when the given 230perl, which usually delivers "false") as its sole argument after the given
223syscall has been executed asynchronously. 231syscall has been executed asynchronously.
224 232
225All functions expecting a filehandle keep a copy of the filehandle 233All functions expecting a filehandle keep a copy of the filehandle
226internally until the request has finished. 234internally until the request has finished.
227 235
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241your 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
242environment, d) use Glib::filename_from_unicode on unicode filenames or e) 250environment, d) use Glib::filename_from_unicode on unicode filenames or e)
243use something else to ensure your scalar has the correct contents. 251use something else to ensure your scalar has the correct contents.
244 252
245This 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
246handles correctly wether it is set or not. 254handles correctly whether it is set or not.
247 255
248=over 4 256=over 4
249 257
250=item $prev_pri = aioreq_pri [$pri] 258=item $prev_pri = aioreq_pri [$pri]
251 259
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311 319
312 320
313=item aio_close $fh, $callback->($status) 321=item aio_close $fh, $callback->($status)
314 322
315Asynchronously close a file and call the callback with the result 323Asynchronously close a file and call the callback with the result
316code. I<WARNING:> although accepted, you should not pass in a perl 324code.
317filehandle here, as perl will likely close the file descriptor another
318time when the filehandle is destroyed. Normally, you can safely call perls
319C<close> or just let filehandles go out of scope.
320 325
321This is supposed to be a bug in the API, so that might change. It's 326Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
322therefore best to avoid this function. 327closing the file descriptor associated with the filehandle itself.
323 328
329Therefore, C<aio_close> will not close the filehandle - instead it will
330use dup2 to overwrite the file descriptor with the write-end of a pipe
331(the pipe fd will be created on demand and will be cached).
332
333Or in other words: the file descriptor will be closed, but it will not be
334free for reuse until the perl filehandle is closed.
335
336=cut
324 337
325=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 338=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
326 339
327=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 340=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
328 341
329Reads 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
330into 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<$dataoffset>
331callback without the actual number of bytes read (or -1 on error, just 344and calls the callback without the actual number of bytes read (or -1 on
345error, just like the syscall).
346
347C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
348offset plus the actual number of bytes read.
349
332like the syscall). If C<offset> is undefined, then the current file offset 350If C<$offset> is undefined, then the current file descriptor offset will
333will be used (and updated), otherwise the file offset will not be changed 351be used (and updated), otherwise the file descriptor offset will not be
334by these calls. 352changed by these calls.
353
354If C<$length> is undefined in C<aio_write>, use the remaining length of
355C<$data>.
356
357If C<$dataoffset> is less than zero, it will be counted from the end of
358C<$data>.
335 359
336The C<$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
337is outstanding. Modifying it can result in segfaults or World War III (if 361is outstanding. Modifying it can result in segfaults or World War III (if
338the necessary/optional hardware is installed). 362the necessary/optional hardware is installed).
339 363
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437 aio_chown "path", 0, -1; 461 aio_chown "path", 0, -1;
438 # same as above: 462 # same as above:
439 aio_chown "path", 0, undef; 463 aio_chown "path", 0, undef;
440 464
441 465
466=item aio_truncate $fh_or_path, $offset, $callback->($status)
467
468Works like truncate(2) or ftruncate(2).
469
470
442=item aio_chmod $fh_or_path, $mode, $callback->($status) 471=item aio_chmod $fh_or_path, $mode, $callback->($status)
443 472
444Works like perl's C<chmod> function. 473Works like perl's C<chmod> function.
445 474
446 475
… …
503 532
504Unlike 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
505directory (i.e. opendir + readdir + closedir). The entries will not be 534directory (i.e. opendir + readdir + closedir). The entries will not be
506sorted, and will B<NOT> include the C<.> and C<..> entries. 535sorted, and will B<NOT> include the C<.> and C<..> entries.
507 536
508The 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
509with 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
510 605
511 606
512=item aio_load $path, $data, $callback->($status) 607=item aio_load $path, $data, $callback->($status)
513 608
514This 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
515memory. Status is the same as with aio_read. 610memory. Status is the same as with aio_read.
516 611
517=cut 612=cut
518 613
519sub aio_load($$;$) { 614sub aio_load($$;$) {
520 aio_block {
521 my ($path, undef, $cb) = @_; 615 my ($path, undef, $cb) = @_;
522 my $data = \$_[1]; 616 my $data = \$_[1];
523 617
524 my $pri = aioreq_pri; 618 my $pri = aioreq_pri;
525 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);
526 625
527 aioreq_pri $pri; 626 aioreq_pri $pri;
528 add $grp aio_open $path, O_RDONLY, 0, sub {
529 my $fh = shift
530 or return $grp->result (-1);
531
532 aioreq_pri $pri;
533 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { 627 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
534 $grp->result ($_[0]); 628 $grp->result ($_[0]);
535 };
536 }; 629 };
537
538 $grp
539 } 630 };
631
632 $grp
540} 633}
541 634
542=item aio_copy $srcpath, $dstpath, $callback->($status) 635=item aio_copy $srcpath, $dstpath, $callback->($status)
543 636
544Try 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
545destination) from C<$srcpath> to C<$dstpath> and call the callback with 638destination) from C<$srcpath> to C<$dstpath> and call the callback with
546the C<0> (error) or C<-1> ok. 639the C<0> (error) or C<-1> ok.
547 640
548This is a composite request that it creates the destination file with 641This is a composite request that creates the destination file with
549mode 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
550C<aio_sendfile>, followed by restoring atime, mtime, access mode and 643C<aio_sendfile>, followed by restoring atime, mtime, access mode and
551uid/gid, in that order. 644uid/gid, in that order.
552 645
553If an error occurs, the partial destination file will be unlinked, if 646If an error occurs, the partial destination file will be unlinked, if
… …
555errors are being ignored. 648errors are being ignored.
556 649
557=cut 650=cut
558 651
559sub aio_copy($$;$) { 652sub aio_copy($$;$) {
560 aio_block {
561 my ($src, $dst, $cb) = @_; 653 my ($src, $dst, $cb) = @_;
562 654
563 my $pri = aioreq_pri; 655 my $pri = aioreq_pri;
564 my $grp = aio_group $cb; 656 my $grp = aio_group $cb;
565 657
566 aioreq_pri $pri; 658 aioreq_pri $pri;
567 add $grp aio_open $src, O_RDONLY, 0, sub { 659 add $grp aio_open $src, O_RDONLY, 0, sub {
568 if (my $src_fh = $_[0]) { 660 if (my $src_fh = $_[0]) {
569 my @stat = stat $src_fh; 661 my @stat = stat $src_fh; # hmm, might bock over nfs?
570 662
571 aioreq_pri $pri; 663 aioreq_pri $pri;
572 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 {
573 if (my $dst_fh = $_[0]) { 665 if (my $dst_fh = $_[0]) {
574 aioreq_pri $pri; 666 aioreq_pri $pri;
575 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 667 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
576 if ($_[0] == $stat[7]) { 668 if ($_[0] == $stat[7]) {
577 $grp->result (0); 669 $grp->result (0);
578 close $src_fh; 670 close $src_fh;
579 671
580 # those should not normally block. should. should.
581 utime $stat[8], $stat[9], $dst;
582 chmod $stat[2] & 07777, $dst_fh;
583 chown $stat[4], $stat[5], $dst_fh;
584 close $dst_fh;
585 } else { 672 my $ch = sub {
586 $grp->result (-1);
587 close $src_fh;
588 close $dst_fh;
589
590 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;
591 add $grp aio_unlink $dst; 678 add $grp aio_close $dst_fh;
679 }
680 };
592 } 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;
593 }; 699 }
594 } else {
595 $grp->result (-1);
596 } 700 };
701 } else {
702 $grp->result (-1);
597 }, 703 }
598
599 } else {
600 $grp->result (-1);
601 } 704 },
705
706 } else {
707 $grp->result (-1);
602 }; 708 }
603
604 $grp
605 } 709 };
710
711 $grp
606} 712}
607 713
608=item aio_move $srcpath, $dstpath, $callback->($status) 714=item aio_move $srcpath, $dstpath, $callback->($status)
609 715
610Try 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
611destination) from C<$srcpath> to C<$dstpath> and call the callback with 717destination) from C<$srcpath> to C<$dstpath> and call the callback with
612the C<0> (error) or C<-1> ok. 718the C<0> (error) or C<-1> ok.
613 719
614This 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
615rename 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
616that is successful, unlinking the C<$srcpath>. 722that is successful, unlinks the C<$srcpath>.
617 723
618=cut 724=cut
619 725
620sub aio_move($$;$) { 726sub aio_move($$;$) {
621 aio_block {
622 my ($src, $dst, $cb) = @_; 727 my ($src, $dst, $cb) = @_;
623 728
624 my $pri = aioreq_pri; 729 my $pri = aioreq_pri;
625 my $grp = aio_group $cb; 730 my $grp = aio_group $cb;
626 731
627 aioreq_pri $pri; 732 aioreq_pri $pri;
628 add $grp aio_rename $src, $dst, sub { 733 add $grp aio_rename $src, $dst, sub {
629 if ($_[0] && $! == EXDEV) { 734 if ($_[0] && $! == EXDEV) {
630 aioreq_pri $pri; 735 aioreq_pri $pri;
631 add $grp aio_copy $src, $dst, sub { 736 add $grp aio_copy $src, $dst, sub {
632 $grp->result ($_[0]);
633
634 if (!$_[0]) {
635 aioreq_pri $pri;
636 add $grp aio_unlink $src;
637 }
638 };
639 } else {
640 $grp->result ($_[0]); 737 $grp->result ($_[0]);
738
739 if (!$_[0]) {
740 aioreq_pri $pri;
741 add $grp aio_unlink $src;
742 }
641 } 743 };
744 } else {
745 $grp->result ($_[0]);
642 }; 746 }
643
644 $grp
645 } 747 };
748
749 $grp
646} 750}
647 751
648=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 752=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
649 753
650Scans a directory (similar to C<aio_readdir>) but additionally tries to 754Scans a directory (similar to C<aio_readdir>) but additionally tries to
… …
670 774
671Implementation notes. 775Implementation notes.
672 776
673The 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.
674 778
779If readdir returns file type information, then this is used directly to
780find directories.
781
675After reading the directory, the modification time, size etc. of the 782Otherwise, after reading the directory, the modification time, size etc.
676directory 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
677isn'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
678entries are directories (if >= 2). Otherwise, no knowledge of the number 785how many entries are directories (if >= 2). Otherwise, no knowledge of the
679of subdirectories will be assumed. 786number of subdirectories will be assumed.
680 787
681Then entries will be sorted into likely directories (everything without 788Then entries will be sorted into likely directories a non-initial dot
682a non-initial dot currently) and likely non-directories (everything 789currently) and likely non-directories (see C<aio_readdirx>). Then every
683else). 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,
684likely directories first. If that succeeds, it assumes that the entry 791in order of their inode numbers. If that succeeds, it assumes that the
685is a directory or a symlink to directory (which will be checked 792entry is a directory or a symlink to directory (which will be checked
686seperately). This is often faster than stat'ing the entry itself because 793seperately). This is often faster than stat'ing the entry itself because
687filesystems might detect the type of the entry without reading the inode 794filesystems might detect the type of the entry without reading the inode
688data (e.g. ext2fs filetype feature). 795data (e.g. ext2fs filetype feature), even on systems that cannot return
796the filetype information on readdir.
689 797
690If 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
691rest of the entries is assumed to be non-directories. 799rest of the entries is assumed to be non-directories.
692 800
693This only works with certainty on POSIX (= UNIX) filesystems, which 801This only works with certainty on POSIX (= UNIX) filesystems, which
… …
698directory counting heuristic. 806directory counting heuristic.
699 807
700=cut 808=cut
701 809
702sub aio_scandir($$;$) { 810sub aio_scandir($$;$) {
703 aio_block {
704 my ($path, $maxreq, $cb) = @_; 811 my ($path, $maxreq, $cb) = @_;
705 812
706 my $pri = aioreq_pri; 813 my $pri = aioreq_pri;
707 814
708 my $grp = aio_group $cb; 815 my $grp = aio_group $cb;
709 816
710 $maxreq = 4 if $maxreq <= 0; 817 $maxreq = 4 if $maxreq <= 0;
711 818
712 # 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
713 aioreq_pri $pri; 827 aioreq_pri $pri;
714 add $grp aio_stat $path, sub { 828 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
829 my $entries = shift
715 return $grp->result () if $_[0]; 830 or return $grp->result ();
716 my $now = time;
717 my $hash1 = join ":", (stat _)[0,1,3,7,9];
718 831
719 # read the directory entries 832 # stat the dir another time
720 aioreq_pri $pri; 833 aioreq_pri $pri;
721 add $grp aio_readdir $path, sub {
722 my $entries = shift
723 or return $grp->result ();
724
725 # stat the dir another time
726 aioreq_pri $pri;
727 add $grp aio_stat $path, sub { 834 add $grp aio_stat $path, sub {
728 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 835 my $hash2 = join ":", (stat _)[0,1,3,7,9];
729 836
730 my $ndirs; 837 my $ndirs;
731 838
732 # take the slow route if anything looks fishy 839 # take the slow route if anything looks fishy
733 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 840 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
734 $ndirs = -1; 841 $ndirs = -1;
735 } else { 842 } else {
736 # if nlink == 2, we are finished 843 # if nlink == 2, we are finished
737 # on non-posix-fs's, we rely on nlink < 2 844 # for non-posix-fs's, we rely on nlink < 2
738 $ndirs = (stat _)[3] - 2 845 $ndirs = (stat _)[3] - 2
739 or return $grp->result ([], $entries); 846 or return $grp->result ([], $entries);
740 } 847 }
741 848
742 # sort into likely dirs and likely nondirs
743 # dirs == files without ".", short entries first
744 $entries = [map $_->[0],
745 sort { $b->[1] cmp $a->[1] }
746 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
747 @$entries];
748
749 my (@dirs, @nondirs); 849 my (@dirs, @nondirs);
750 850
751 my $statgrp = add $grp aio_group sub { 851 my $statgrp = add $grp aio_group sub {
752 $grp->result (\@dirs, \@nondirs); 852 $grp->result (\@dirs, \@nondirs);
753 }; 853 };
754 854
755 limit $statgrp $maxreq; 855 limit $statgrp $maxreq;
756 feed $statgrp sub { 856 feed $statgrp sub {
757 return unless @$entries; 857 return unless @$entries;
758 my $entry = pop @$entries; 858 my $entry = shift @$entries;
759 859
760 aioreq_pri $pri; 860 aioreq_pri $pri;
761 add $statgrp aio_stat "$path/$entry/.", sub { 861 add $statgrp aio_stat "$path/$entry/.", sub {
762 if ($_[0] < 0) { 862 if ($_[0] < 0) {
763 push @nondirs, $entry; 863 push @nondirs, $entry;
764 } else { 864 } else {
765 # need to check for real directory 865 # need to check for real directory
766 aioreq_pri $pri; 866 aioreq_pri $pri;
767 add $statgrp aio_lstat "$path/$entry", sub { 867 add $statgrp aio_lstat "$path/$entry", sub {
768 if (-d _) { 868 if (-d _) {
769 push @dirs, $entry; 869 push @dirs, $entry;
770 870
771 unless (--$ndirs) { 871 unless (--$ndirs) {
772 push @nondirs, @$entries; 872 push @nondirs, @$entries;
773 feed $statgrp; 873 feed $statgrp;
774 }
775 } else {
776 push @nondirs, $entry;
777 } 874 }
875 } else {
876 push @nondirs, $entry;
778 } 877 }
779 } 878 }
780 }; 879 }
781 }; 880 };
782 }; 881 };
783 }; 882 };
784 }; 883 };
785
786 $grp
787 } 884 };
885
886 $grp
788} 887}
789 888
790=item aio_rmtree $path, $callback->($status) 889=item aio_rmtree $path, $callback->($status)
791 890
792Delete a directory tree starting (and including) C<$path>, return the 891Delete a directory tree starting (and including) C<$path>, return the
… …
796 895
797=cut 896=cut
798 897
799sub aio_rmtree; 898sub aio_rmtree;
800sub aio_rmtree($;$) { 899sub aio_rmtree($;$) {
801 aio_block {
802 my ($path, $cb) = @_; 900 my ($path, $cb) = @_;
803 901
804 my $pri = aioreq_pri; 902 my $pri = aioreq_pri;
805 my $grp = aio_group $cb; 903 my $grp = aio_group $cb;
806 904
807 aioreq_pri $pri; 905 aioreq_pri $pri;
808 add $grp aio_scandir $path, 0, sub { 906 add $grp aio_scandir $path, 0, sub {
809 my ($dirs, $nondirs) = @_; 907 my ($dirs, $nondirs) = @_;
810 908
811 my $dirgrp = aio_group sub { 909 my $dirgrp = aio_group sub {
812 add $grp aio_rmdir $path, sub { 910 add $grp aio_rmdir $path, sub {
813 $grp->result ($_[0]); 911 $grp->result ($_[0]);
814 };
815 }; 912 };
816
817 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
818 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
819
820 add $grp $dirgrp;
821 }; 913 };
822 914
823 $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;
824 } 919 };
920
921 $grp
825} 922}
923
924=item aio_sync $callback->($status)
925
926Asynchronously call sync and call the callback when finished.
826 927
827=item aio_fsync $fh, $callback->($status) 928=item aio_fsync $fh, $callback->($status)
828 929
829Asynchronously call fsync on the given filehandle and call the callback 930Asynchronously call fsync on the given filehandle and call the callback
830with the fsync result code. 931with the fsync result code.
… …
834Asynchronously call fdatasync on the given filehandle and call the 935Asynchronously call fdatasync on the given filehandle and call the
835callback with the fdatasync result code. 936callback with the fdatasync result code.
836 937
837If 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
838detected, 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
962Passes C<0> when everything went ok, and C<-1> on error.
963
964=cut
965
966sub aio_pathsync($;$) {
967 my ($path, $cb) = @_;
968
969 my $pri = aioreq_pri;
970 my $grp = aio_group $cb;
971
972 aioreq_pri $pri;
973 add $grp aio_open $path, O_RDONLY, 0, sub {
974 my ($fh) = @_;
975 if ($fh) {
976 aioreq_pri $pri;
977 add $grp aio_fsync $fh, sub {
978 $grp->result ($_[0]);
979
980 aioreq_pri $pri;
981 add $grp aio_close $fh;
982 };
983 } else {
984 $grp->result (-1);
985 }
986 };
987
988 $grp
989}
839 990
840=item aio_group $callback->(...) 991=item aio_group $callback->(...)
841 992
842This is a very special aio request: Instead of doing something, it is a 993This is a very special aio request: Instead of doing something, it is a
843container for other aio requests, which is useful if you want to bundle 994container for other aio requests, which is useful if you want to bundle
… …
893=item cancel $req 1044=item cancel $req
894 1045
895Cancels the request, if possible. Has the effect of skipping execution 1046Cancels the request, if possible. Has the effect of skipping execution
896when entering the B<execute> state and skipping calling the callback when 1047when entering the B<execute> state and skipping calling the callback when
897entering the the B<result> state, but will leave the request otherwise 1048entering the the B<result> state, but will leave the request otherwise
898untouched. That means that requests that currently execute will not be 1049untouched (with the exception of readdir). That means that requests that
899stopped and resources held by the request will not be freed prematurely. 1050currently execute will not be stopped and resources held by the request
1051will not be freed prematurely.
900 1052
901=item cb $req $callback->(...) 1053=item cb $req $callback->(...)
902 1054
903Replace (or simply set) the callback registered to the request. 1055Replace (or simply set) the callback registered to the request.
904 1056
… …
955Their lifetime, simplified, looks like this: when they are empty, they 1107Their lifetime, simplified, looks like this: when they are empty, they
956will finish very quickly. If they contain only requests that are in the 1108will finish very quickly. If they contain only requests that are in the
957C<done> state, they will also finish. Otherwise they will continue to 1109C<done> state, they will also finish. Otherwise they will continue to
958exist. 1110exist.
959 1111
960That means after creating a group you have some time to add requests. And 1112That means after creating a group you have some time to add requests
961in the callbacks of those requests, you can add further requests to the 1113(precisely before the callback has been invoked, which is only done within
962group. And only when all those requests have finished will the the group 1114the C<poll_cb>). And in the callbacks of those requests, you can add
963itself finish. 1115further requests to the group. And only when all those requests have
1116finished will the the group itself finish.
964 1117
965=over 4 1118=over 4
966 1119
967=item add $grp ... 1120=item add $grp ...
968 1121
… …
980itself. Useful when you queued a lot of events but got a result early. 1133itself. Useful when you queued a lot of events but got a result early.
981 1134
982=item $grp->result (...) 1135=item $grp->result (...)
983 1136
984Set the result value(s) that will be passed to the group callback when all 1137Set the result value(s) that will be passed to the group callback when all
985subrequests have finished and set thre groups errno to the current value 1138subrequests have finished and set the groups errno to the current value
986of errno (just like calling C<errno> without an error number). By default, 1139of errno (just like calling C<errno> without an error number). By default,
987no argument will be passed and errno is zero. 1140no argument will be passed and errno is zero.
988 1141
989=item $grp->errno ([$errno]) 1142=item $grp->errno ([$errno])
990 1143
… …
1001=item feed $grp $callback->($grp) 1154=item feed $grp $callback->($grp)
1002 1155
1003Sets a feeder/generator on this group: every group can have an attached 1156Sets a feeder/generator on this group: every group can have an attached
1004generator that generates requests if idle. The idea behind this is that, 1157generator that generates requests if idle. The idea behind this is that,
1005although you could just queue as many requests as you want in a group, 1158although you could just queue as many requests as you want in a group,
1006this might starve other requests for a potentially long time. For 1159this might starve other requests for a potentially long time. For example,
1007example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1160C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
1008requests, delaying any later requests for a long time. 1161delaying any later requests for a long time.
1009 1162
1010To avoid this, and allow incremental generation of requests, you can 1163To avoid this, and allow incremental generation of requests, you can
1011instead a group and set a feeder on it that generates those requests. The 1164instead a group and set a feeder on it that generates those requests. The
1012feed callback will be called whenever there are few enough (see C<limit>, 1165feed callback will be called whenever there are few enough (see C<limit>,
1013below) requests active in the group itself and is expected to queue more 1166below) requests active in the group itself and is expected to queue more
… …
1017not impose any limits). 1170not impose any limits).
1018 1171
1019If the feed does not queue more requests when called, it will be 1172If the feed does not queue more requests when called, it will be
1020automatically removed from the group. 1173automatically removed from the group.
1021 1174
1022If the feed limit is C<0>, it will be set to C<2> automatically. 1175If the feed limit is C<0> when this method is called, it will be set to
1176C<2> automatically.
1023 1177
1024Example: 1178Example:
1025 1179
1026 # stat all files in @files, but only ever use four aio requests concurrently: 1180 # stat all files in @files, but only ever use four aio requests concurrently:
1027 1181
… …
1039Sets the feeder limit for the group: The feeder will be called whenever 1193Sets the feeder limit for the group: The feeder will be called whenever
1040the group contains less than this many requests. 1194the group contains less than this many requests.
1041 1195
1042Setting the limit to C<0> will pause the feeding process. 1196Setting the limit to C<0> will pause the feeding process.
1043 1197
1198The default value for the limit is C<0>, but note that setting a feeder
1199automatically bumps it up to C<2>.
1200
1044=back 1201=back
1045 1202
1046=head2 SUPPORT FUNCTIONS 1203=head2 SUPPORT FUNCTIONS
1047 1204
1048=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1205=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
1050=over 4 1207=over 4
1051 1208
1052=item $fileno = IO::AIO::poll_fileno 1209=item $fileno = IO::AIO::poll_fileno
1053 1210
1054Return the I<request result pipe file descriptor>. This filehandle must be 1211Return the I<request result pipe file descriptor>. This filehandle must be
1055polled for reading by some mechanism outside this module (e.g. Event or 1212polled for reading by some mechanism outside this module (e.g. EV, Glib,
1056select, see below or the SYNOPSIS). If the pipe becomes readable you have 1213select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1057to call C<poll_cb> to check the results. 1214you have to call C<poll_cb> to check the results.
1058 1215
1059See C<poll_cb> for an example. 1216See C<poll_cb> for an example.
1060 1217
1061=item IO::AIO::poll_cb 1218=item IO::AIO::poll_cb
1062 1219
1063Process some outstanding events on the result pipe. You have to call this 1220Process some outstanding events on the result pipe. You have to call this
1064regularly. Returns the number of events processed. Returns immediately 1221regularly. Returns C<0> if all events could be processed, or C<-1> if it
1222returned earlier for whatever reason. Returns immediately when no events
1065when no events are outstanding. The amount of events processed depends on 1223are outstanding. The amount of events processed depends on the settings of
1066the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1224C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1067 1225
1068If not all requests were processed for whatever reason, the filehandle 1226If not all requests were processed for whatever reason, the filehandle
1069will still be ready when C<poll_cb> returns. 1227will still be ready when C<poll_cb> returns, so normally you don't have to
1228do anything special to have it called later.
1070 1229
1071Example: Install an Event watcher that automatically calls 1230Example: Install an Event watcher that automatically calls
1072IO::AIO::poll_cb with high priority: 1231IO::AIO::poll_cb with high priority (more examples can be found in the
1232SYNOPSIS section, at the top of this document):
1073 1233
1074 Event->io (fd => IO::AIO::poll_fileno, 1234 Event->io (fd => IO::AIO::poll_fileno,
1075 poll => 'r', async => 1, 1235 poll => 'r', async => 1,
1076 cb => \&IO::AIO::poll_cb); 1236 cb => \&IO::AIO::poll_cb);
1077 1237
… …
1188 1348
1189The default is probably ok in most situations, especially if thread 1349The default is probably ok in most situations, especially if thread
1190creation is fast. If thread creation is very slow on your system you might 1350creation is fast. If thread creation is very slow on your system you might
1191want to use larger values. 1351want to use larger values.
1192 1352
1193=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1353=item IO::AIO::max_outstanding $maxreqs
1194 1354
1195This is a very bad function to use in interactive programs because it 1355This is a very bad function to use in interactive programs because it
1196blocks, and a bad way to reduce concurrency because it is inexact: Better 1356blocks, and a bad way to reduce concurrency because it is inexact: Better
1197use an C<aio_group> together with a feed callback. 1357use an C<aio_group> together with a feed callback.
1198 1358
1199Sets the maximum number of outstanding requests to C<$nreqs>. If you 1359Sets the maximum number of outstanding requests to C<$nreqs>. If you
1200to queue up more than this number of requests, the next call to the 1360do queue up more than this number of requests, the next call to the
1201C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) 1361C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1202function will block until the limit is no longer exceeded. 1362function will block until the limit is no longer exceeded.
1203 1363
1204The default value is very large, so there is no practical limit on the 1364The default value is very large, so there is no practical limit on the
1205number of outstanding requests. 1365number of outstanding requests.
1206 1366
1207You can still queue as many requests as you want. Therefore, 1367You can still queue as many requests as you want. Therefore,
1208C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1368C<max_outstanding> is mainly useful in simple scripts (with low values) or
1209as a stop gap to shield against fatal memory overflow (with large values). 1369as a stop gap to shield against fatal memory overflow (with large values).
1210 1370
1211=back 1371=back
1212 1372
1213=head3 STATISTICAL INFORMATION 1373=head3 STATISTICAL INFORMATION
… …
1235but not yet processed by poll_cb). 1395but not yet processed by poll_cb).
1236 1396
1237=back 1397=back
1238 1398
1239=cut 1399=cut
1240
1241# support function to convert a fd into a perl filehandle
1242sub _fd2fh {
1243 return undef if $_[0] < 0;
1244
1245 # try to generate nice filehandles
1246 my $sym = "IO::AIO::fd#$_[0]";
1247 local *$sym;
1248
1249 open *$sym, "+<&=$_[0]" # usually works under any unix
1250 or open *$sym, "<&=$_[0]" # cygwin needs this
1251 or open *$sym, ">&=$_[0]" # or this
1252 or return undef;
1253
1254 *$sym
1255}
1256 1400
1257min_parallel 8; 1401min_parallel 8;
1258 1402
1259END { flush } 1403END { flush }
1260 1404
… …
1284bytes of memory. In addition, stat requests need a stat buffer (possibly 1428bytes of memory. In addition, stat requests need a stat buffer (possibly
1285a few hundred bytes), readdir requires a result buffer and so on. Perl 1429a few hundred bytes), readdir requires a result buffer and so on. Perl
1286scalars and other data passed into aio requests will also be locked and 1430scalars and other data passed into aio requests will also be locked and
1287will consume memory till the request has entered the done state. 1431will consume memory till the request has entered the done state.
1288 1432
1289This is now awfully much, so queuing lots of requests is not usually a 1433This is not awfully much, so queuing lots of requests is not usually a
1290problem. 1434problem.
1291 1435
1292Per-thread usage: 1436Per-thread usage:
1293 1437
1294In the execution phase, some aio requests require more memory for 1438In the execution phase, some aio requests require more memory for
… …
1299 1443
1300Known bugs will be fixed in the next release. 1444Known bugs will be fixed in the next release.
1301 1445
1302=head1 SEE ALSO 1446=head1 SEE ALSO
1303 1447
1304L<Coro::AIO>. 1448L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1449more natural syntax.
1305 1450
1306=head1 AUTHOR 1451=head1 AUTHOR
1307 1452
1308 Marc Lehmann <schmorp@schmorp.de> 1453 Marc Lehmann <schmorp@schmorp.de>
1309 http://home.schmorp.de/ 1454 http://home.schmorp.de/

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