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Revision 1.172 by root, Thu Jan 7 18:08:21 2010 UTC vs.
Revision 1.225 by root, Tue Apr 10 05:01:33 2012 UTC

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4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub { 9 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10 my $fh = shift 10 my $fh = shift
11 or die "/etc/passwd: $!"; 11 or die "/etc/passwd: $!";
12 ... 12 ...
13 }; 13 };
14 14
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25 my $req = aio_unlink "/tmp/file", sub { }; 25 my $req = aio_unlink "/tmp/file", sub { };
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
31 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
32 use AnyEvent::AIO;
33
34 # EV integration
35 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
36
37 # Event integration
38 Event->io (fd => IO::AIO::poll_fileno,
39 poll => 'r',
40 cb => \&IO::AIO::poll_cb);
41
42 # Glib/Gtk2 integration
43 add_watch Glib::IO IO::AIO::poll_fileno,
44 in => sub { IO::AIO::poll_cb; 1 };
45
46 # Tk integration
47 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
48 readable => \&IO::AIO::poll_cb);
49
50 # Danga::Socket integration
51 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
52 \&IO::AIO::poll_cb);
53 30
54=head1 DESCRIPTION 31=head1 DESCRIPTION
55 32
56This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
57operating system supports. It is implemented as an interface to C<libeio> 34operating system supports. It is implemented as an interface to C<libeio>
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99 76
100 # register the IO::AIO callback with EV 77 # register the IO::AIO callback with EV
101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102 79
103 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
105 my $fh = shift 82 my $fh = shift
106 or die "error while opening: $!"; 83 or die "error while opening: $!";
107 84
108 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
109 my $size = -s $fh; 86 my $size = -s $fh;
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191use common::sense; 168use common::sense;
192 169
193use base 'Exporter'; 170use base 'Exporter';
194 171
195BEGIN { 172BEGIN {
196 our $VERSION = '3.4'; 173 our $VERSION = '4.15';
197 174
198 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
199 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
200 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
201 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
179 aio_pathsync aio_readahead aio_fiemap
202 aio_rename aio_link aio_move aio_copy aio_group 180 aio_rename aio_link aio_move aio_copy aio_group
203 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
204 aio_chmod aio_utime aio_truncate 182 aio_chmod aio_utime aio_truncate
205 aio_msync aio_mtouch aio_statvfs); 183 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs
185 aio_wd);
206 186
207 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
208 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
209 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
210 nreqs nready npending nthreads 190 nreqs nready npending nthreads
211 max_poll_time max_poll_reqs 191 max_poll_time max_poll_reqs
212 sendfile fadvise); 192 sendfile fadvise madvise
193 mmap munmap munlock munlockall);
213 194
214 push @AIO_REQ, qw(aio_busy); # not exported 195 push @AIO_REQ, qw(aio_busy); # not exported
215 196
216 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
217 198
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219 XSLoader::load ("IO::AIO", $VERSION); 200 XSLoader::load ("IO::AIO", $VERSION);
220} 201}
221 202
222=head1 FUNCTIONS 203=head1 FUNCTIONS
223 204
224=head2 AIO REQUEST FUNCTIONS 205=head2 QUICK OVERVIEW
206
207This section simply lists the prototypes of the most important functions
208for quick reference. See the following sections for function-by-function
209documentation.
210
211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status)
214 aio_seek $fh,$offset,$whence, $callback->($offs)
215 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
217 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
218 aio_readahead $fh,$offset,$length, $callback->($retval)
219 aio_stat $fh_or_path, $callback->($status)
220 aio_lstat $fh, $callback->($status)
221 aio_statvfs $fh_or_path, $callback->($statvfs)
222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
223 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_truncate $fh_or_path, $offset, $callback->($status)
226 aio_unlink $pathname, $callback->($status)
227 aio_mknod $pathname, $mode, $dev, $callback->($status)
228 aio_link $srcpath, $dstpath, $callback->($status)
229 aio_symlink $srcpath, $dstpath, $callback->($status)
230 aio_readlink $pathname, $callback->($link)
231 aio_realpath $pathname, $callback->($link)
232 aio_rename $srcpath, $dstpath, $callback->($status)
233 aio_mkdir $pathname, $mode, $callback->($status)
234 aio_rmdir $pathname, $callback->($status)
235 aio_readdir $pathname, $callback->($entries)
236 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
237 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
238 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
239 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
240 aio_load $pathname, $data, $callback->($status)
241 aio_copy $srcpath, $dstpath, $callback->($status)
242 aio_move $srcpath, $dstpath, $callback->($status)
243 aio_rmtree $pathname, $callback->($status)
244 aio_sync $callback->($status)
245 aio_syncfs $fh, $callback->($status)
246 aio_fsync $fh, $callback->($status)
247 aio_fdatasync $fh, $callback->($status)
248 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
249 aio_pathsync $pathname, $callback->($status)
250 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
252 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
253 aio_mlockall $flags, $callback->($status)
254 aio_group $callback->(...)
255 aio_nop $callback->()
256
257 $prev_pri = aioreq_pri [$pri]
258 aioreq_nice $pri_adjust
259
260 IO::AIO::poll_wait
261 IO::AIO::poll_cb
262 IO::AIO::poll
263 IO::AIO::flush
264 IO::AIO::max_poll_reqs $nreqs
265 IO::AIO::max_poll_time $seconds
266 IO::AIO::min_parallel $nthreads
267 IO::AIO::max_parallel $nthreads
268 IO::AIO::max_idle $nthreads
269 IO::AIO::idle_timeout $seconds
270 IO::AIO::max_outstanding $maxreqs
271 IO::AIO::nreqs
272 IO::AIO::nready
273 IO::AIO::npending
274
275 IO::AIO::sendfile $ofh, $ifh, $offset, $count
276 IO::AIO::fadvise $fh, $offset, $len, $advice
277 IO::AIO::madvise $scalar, $offset, $length, $advice
278 IO::AIO::mprotect $scalar, $offset, $length, $protect
279 IO::AIO::munlock $scalar, $offset = 0, $length = undef
280 IO::AIO::munlockall
281
282=head2 API NOTES
225 283
226All the C<aio_*> calls are more or less thin wrappers around the syscall 284All the C<aio_*> calls are more or less thin wrappers around the syscall
227with the same name (sans C<aio_>). The arguments are similar or identical, 285with the same name (sans C<aio_>). The arguments are similar or identical,
228and they all accept an additional (and optional) C<$callback> argument 286and they all accept an additional (and optional) C<$callback> argument
229which must be a code reference. This code reference will get called with 287which must be a code reference. This code reference will be called after
230the syscall return code (e.g. most syscalls return C<-1> on error, unlike 288the syscall has been executed in an asynchronous fashion. The results
231perl, which usually delivers "false") as its sole argument after the given 289of the request will be passed as arguments to the callback (and, if an
232syscall has been executed asynchronously. 290error occured, in C<$!>) - for most requests the syscall return code (e.g.
291most syscalls return C<-1> on error, unlike perl, which usually delivers
292"false").
293
294Some requests (such as C<aio_readdir>) pass the actual results and
295communicate failures by passing C<undef>.
233 296
234All functions expecting a filehandle keep a copy of the filehandle 297All functions expecting a filehandle keep a copy of the filehandle
235internally until the request has finished. 298internally until the request has finished.
236 299
237All functions return request objects of type L<IO::AIO::REQ> that allow 300All functions return request objects of type L<IO::AIO::REQ> that allow
238further manipulation of those requests while they are in-flight. 301further manipulation of those requests while they are in-flight.
239 302
240The pathnames you pass to these routines I<must> be absolute and 303The pathnames you pass to these routines I<should> be absolute. The
241encoded as octets. The reason for the former is that at the time the 304reason for this is that at the time the request is being executed, the
242request is being executed, the current working directory could have 305current working directory could have changed. Alternatively, you can
243changed. Alternatively, you can make sure that you never change the 306make sure that you never change the current working directory anywhere
244current working directory anywhere in the program and then use relative 307in the program and then use relative paths. You can also take advantage
245paths. 308of IO::AIOs working directory abstraction, that lets you specify paths
309relative to some previously-opened "working directory object" - see the
310description of the C<IO::AIO::WD> class later in this document.
246 311
247To encode pathnames as octets, either make sure you either: a) always pass 312To encode pathnames as octets, either make sure you either: a) always pass
248in filenames you got from outside (command line, readdir etc.) without 313in filenames you got from outside (command line, readdir etc.) without
249tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 314tinkering, b) are in your native filesystem encoding, c) use the Encode
250your pathnames to the locale (or other) encoding in effect in the user 315module and encode your pathnames to the locale (or other) encoding in
251environment, d) use Glib::filename_from_unicode on unicode filenames or e) 316effect in the user environment, d) use Glib::filename_from_unicode on
252use something else to ensure your scalar has the correct contents. 317unicode filenames or e) use something else to ensure your scalar has the
318correct contents.
253 319
254This works, btw. independent of the internal UTF-8 bit, which IO::AIO 320This works, btw. independent of the internal UTF-8 bit, which IO::AIO
255handles correctly whether it is set or not. 321handles correctly whether it is set or not.
322
323=head2 AIO REQUEST FUNCTIONS
256 324
257=over 4 325=over 4
258 326
259=item $prev_pri = aioreq_pri [$pri] 327=item $prev_pri = aioreq_pri [$pri]
260 328
… …
307by the umask in effect then the request is being executed, so better never 375by the umask in effect then the request is being executed, so better never
308change the umask. 376change the umask.
309 377
310Example: 378Example:
311 379
312 aio_open "/etc/passwd", O_RDONLY, 0, sub { 380 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
313 if ($_[0]) { 381 if ($_[0]) {
314 print "open successful, fh is $_[0]\n"; 382 print "open successful, fh is $_[0]\n";
315 ... 383 ...
316 } else { 384 } else {
317 die "open failed: $!\n"; 385 die "open failed: $!\n";
318 } 386 }
319 }; 387 };
320 388
389In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
390C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
391following POSIX and non-POSIX constants are available (missing ones on
392your system are, as usual, C<0>):
393
394C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
395C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
396C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
397
321 398
322=item aio_close $fh, $callback->($status) 399=item aio_close $fh, $callback->($status)
323 400
324Asynchronously close a file and call the callback with the result 401Asynchronously close a file and call the callback with the result
325code. 402code.
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333 410
334Or in other words: the file descriptor will be closed, but it will not be 411Or in other words: the file descriptor will be closed, but it will not be
335free for reuse until the perl filehandle is closed. 412free for reuse until the perl filehandle is closed.
336 413
337=cut 414=cut
415
416=item aio_seek $fh, $offset, $whence, $callback->($offs)
417
418Seeks the filehandle to the new C<$offset>, similarly to perl's
419C<sysseek>. The C<$whence> can use the traditional values (C<0> for
420C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
421C<IO::AIO::SEEK_END>).
422
423The resulting absolute offset will be passed to the callback, or C<-1> in
424case of an error.
425
426In theory, the C<$whence> constants could be different than the
427corresponding values from L<Fcntl>, but perl guarantees they are the same,
428so don't panic.
429
430As a GNU/Linux (and maybe Solaris) extension, also the constants
431C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
432could be found. No guarantees about suitability for use in C<aio_seek> or
433Perl's C<sysseek> can be made though, although I would naively assume they
434"just work".
338 435
339=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 436=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
340 437
341=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 438=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
342 439
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375 472
376Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 473Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
377reading at byte offset C<$in_offset>, and starts writing at the current 474reading at byte offset C<$in_offset>, and starts writing at the current
378file offset of C<$out_fh>. Because of that, it is not safe to issue more 475file offset of C<$out_fh>. Because of that, it is not safe to issue more
379than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 476than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
380other. 477other. The same C<$in_fh> works fine though, as this function does not
478move or use the file offset of C<$in_fh>.
381 479
480Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
481are written, and there is no way to find out how many more bytes have been
482read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
483number of bytes written to C<$out_fh>. Only if the result value equals
484C<$length> one can assume that C<$length> bytes have been read.
485
486Unlike with other C<aio_> functions, it makes a lot of sense to use
487C<aio_sendfile> on non-blocking sockets, as long as one end (typically
488the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
489the socket I/O will be non-blocking. Note, however, that you can run
490into a trap where C<aio_sendfile> reads some data with readahead, then
491fails to write all data, and when the socket is ready the next time, the
492data in the cache is already lost, forcing C<aio_sendfile> to again hit
493the disk. Explicit C<aio_read> + C<aio_write> let's you better control
494resource usage.
495
382This call tries to make use of a native C<sendfile> syscall to provide 496This call tries to make use of a native C<sendfile>-like syscall to
383zero-copy operation. For this to work, C<$out_fh> should refer to a 497provide zero-copy operation. For this to work, C<$out_fh> should refer to
384socket, and C<$in_fh> should refer to mmap'able file. 498a socket, and C<$in_fh> should refer to an mmap'able file.
385 499
386If a native sendfile cannot be found or it fails with C<ENOSYS>, 500If a native sendfile cannot be found or it fails with C<ENOSYS>,
387C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 501C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
388it will be emulated, so you can call C<aio_sendfile> on any type of 502C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
389filehandle regardless of the limitations of the operating system. 503type of filehandle regardless of the limitations of the operating system.
390 504
391Please note, however, that C<aio_sendfile> can read more bytes from 505As native sendfile syscalls (as practically any non-POSIX interface hacked
392C<$in_fh> than are written, and there is no way to find out how many 506together in a hurry to improve benchmark numbers) tend to be rather buggy
393bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 507on many systems, this implementation tries to work around some known bugs
394provides the number of bytes written to C<$out_fh>. Only if the result 508in Linux and FreeBSD kernels (probably others, too), but that might fail,
395value equals C<$length> one can assume that C<$length> bytes have been 509so you really really should check the return value of C<aio_sendfile> -
396read. 510fewre bytes than expected might have been transferred.
397 511
398 512
399=item aio_readahead $fh,$offset,$length, $callback->($retval) 513=item aio_readahead $fh,$offset,$length, $callback->($retval)
400 514
401C<aio_readahead> populates the page cache with data from a file so that 515C<aio_readahead> populates the page cache with data from a file so that
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424 538
425Currently, the stats are always 64-bit-stats, i.e. instead of returning an 539Currently, the stats are always 64-bit-stats, i.e. instead of returning an
426error when stat'ing a large file, the results will be silently truncated 540error when stat'ing a large file, the results will be silently truncated
427unless perl itself is compiled with large file support. 541unless perl itself is compiled with large file support.
428 542
543To help interpret the mode and dev/rdev stat values, IO::AIO offers the
544following constants and functions (if not implemented, the constants will
545be C<0> and the functions will either C<croak> or fall back on traditional
546behaviour).
547
548C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
549C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
550C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
551
429Example: Print the length of F</etc/passwd>: 552Example: Print the length of F</etc/passwd>:
430 553
431 aio_stat "/etc/passwd", sub { 554 aio_stat "/etc/passwd", sub {
432 $_[0] and die "stat failed: $!"; 555 $_[0] and die "stat failed: $!";
433 print "size is ", -s _, "\n"; 556 print "size is ", -s _, "\n";
434 }; 557 };
435 558
436 559
437=item aio_statvfs $fh_or_path, $callback->($statvfs) 560=item aio_statvfs $fh_or_path, $callback->($statvfs)
438 561
439Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on 562Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
440whether a file handle or path was passed. 563whether a file handle or path was passed.
441 564
442On success, the callback is passed a hash reference with the following 565On success, the callback is passed a hash reference with the following
… …
524 647
525Asynchronously unlink (delete) a file and call the callback with the 648Asynchronously unlink (delete) a file and call the callback with the
526result code. 649result code.
527 650
528 651
529=item aio_mknod $path, $mode, $dev, $callback->($status) 652=item aio_mknod $pathname, $mode, $dev, $callback->($status)
530 653
531[EXPERIMENTAL] 654[EXPERIMENTAL]
532 655
533Asynchronously create a device node (or fifo). See mknod(2). 656Asynchronously create a device node (or fifo). See mknod(2).
534 657
535The only (POSIX-) portable way of calling this function is: 658The only (POSIX-) portable way of calling this function is:
536 659
537 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 660 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
538 661
662See C<aio_stat> for info about some potentially helpful extra constants
663and functions.
539 664
540=item aio_link $srcpath, $dstpath, $callback->($status) 665=item aio_link $srcpath, $dstpath, $callback->($status)
541 666
542Asynchronously create a new link to the existing object at C<$srcpath> at 667Asynchronously create a new link to the existing object at C<$srcpath> at
543the path C<$dstpath> and call the callback with the result code. 668the path C<$dstpath> and call the callback with the result code.
… …
547 672
548Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 673Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
549the path C<$dstpath> and call the callback with the result code. 674the path C<$dstpath> and call the callback with the result code.
550 675
551 676
552=item aio_readlink $path, $callback->($link) 677=item aio_readlink $pathname, $callback->($link)
553 678
554Asynchronously read the symlink specified by C<$path> and pass it to 679Asynchronously read the symlink specified by C<$path> and pass it to
555the callback. If an error occurs, nothing or undef gets passed to the 680the callback. If an error occurs, nothing or undef gets passed to the
556callback. 681callback.
557 682
558 683
684=item aio_realpath $pathname, $callback->($path)
685
686Asynchronously make the path absolute and resolve any symlinks in
687C<$path>. The resulting path only consists of directories (Same as
688L<Cwd::realpath>).
689
690This request can be used to get the absolute path of the current working
691directory by passing it a path of F<.> (a single dot).
692
693
559=item aio_rename $srcpath, $dstpath, $callback->($status) 694=item aio_rename $srcpath, $dstpath, $callback->($status)
560 695
561Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 696Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
562rename(2) and call the callback with the result code. 697rename(2) and call the callback with the result code.
563 698
… …
585array-ref with the filenames. 720array-ref with the filenames.
586 721
587 722
588=item aio_readdirx $pathname, $flags, $callback->($entries, $flags) 723=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
589 724
590Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune 725Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
591behaviour and output format. In case of an error, C<$entries> will be 726tune behaviour and output format. In case of an error, C<$entries> will be
592C<undef>. 727C<undef>.
593 728
594The flags are a combination of the following constants, ORed together (the 729The flags are a combination of the following constants, ORed together (the
595flags will also be passed to the callback, possibly modified): 730flags will also be passed to the callback, possibly modified):
596 731
597=over 4 732=over 4
598 733
599=item IO::AIO::READDIR_DENTS 734=item IO::AIO::READDIR_DENTS
600 735
601When this flag is off, then the callback gets an arrayref with of names 736When this flag is off, then the callback gets an arrayref consisting of
602only (as with C<aio_readdir>), otherwise it gets an arrayref with 737names only (as with C<aio_readdir>), otherwise it gets an arrayref with
603C<[$name, $type, $inode]> arrayrefs, each describing a single directory 738C<[$name, $type, $inode]> arrayrefs, each describing a single directory
604entry in more detail. 739entry in more detail.
605 740
606C<$name> is the name of the entry. 741C<$name> is the name of the entry.
607 742
… …
620systems that do not deliver the inode information. 755systems that do not deliver the inode information.
621 756
622=item IO::AIO::READDIR_DIRS_FIRST 757=item IO::AIO::READDIR_DIRS_FIRST
623 758
624When this flag is set, then the names will be returned in an order where 759When this flag is set, then the names will be returned in an order where
625likely directories come first. This is useful when you need to quickly 760likely directories come first, in optimal stat order. This is useful when
626find directories, or you want to find all directories while avoiding to 761you need to quickly find directories, or you want to find all directories
627stat() each entry. 762while avoiding to stat() each entry.
628 763
629If the system returns type information in readdir, then this is used 764If the system returns type information in readdir, then this is used
630to find directories directly. Otherwise, likely directories are files 765to find directories directly. Otherwise, likely directories are names
631beginning with ".", or otherwise files with no dots, of which files with 766beginning with ".", or otherwise names with no dots, of which names with
632short names are tried first. 767short names are tried first.
633 768
634=item IO::AIO::READDIR_STAT_ORDER 769=item IO::AIO::READDIR_STAT_ORDER
635 770
636When this flag is set, then the names will be returned in an order 771When this flag is set, then the names will be returned in an order
… …
643 778
644=item IO::AIO::READDIR_FOUND_UNKNOWN 779=item IO::AIO::READDIR_FOUND_UNKNOWN
645 780
646This flag should not be set when calling C<aio_readdirx>. Instead, it 781This flag should not be set when calling C<aio_readdirx>. Instead, it
647is being set by C<aio_readdirx>, when any of the C<$type>'s found were 782is being set by C<aio_readdirx>, when any of the C<$type>'s found were
648C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all 783C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
649C<$type>'s are known, which can be used to speed up some algorithms. 784C<$type>'s are known, which can be used to speed up some algorithms.
650 785
651=back 786=back
652 787
653 788
654=item aio_load $path, $data, $callback->($status) 789=item aio_load $pathname, $data, $callback->($status)
655 790
656This is a composite request that tries to fully load the given file into 791This is a composite request that tries to fully load the given file into
657memory. Status is the same as with aio_read. 792memory. Status is the same as with aio_read.
658 793
659=cut 794=cut
… …
781 if ($_[0] && $! == EXDEV) { 916 if ($_[0] && $! == EXDEV) {
782 aioreq_pri $pri; 917 aioreq_pri $pri;
783 add $grp aio_copy $src, $dst, sub { 918 add $grp aio_copy $src, $dst, sub {
784 $grp->result ($_[0]); 919 $grp->result ($_[0]);
785 920
786 if (!$_[0]) { 921 unless ($_[0]) {
787 aioreq_pri $pri; 922 aioreq_pri $pri;
788 add $grp aio_unlink $src; 923 add $grp aio_unlink $src;
789 } 924 }
790 }; 925 };
791 } else { 926 } else {
… …
794 }; 929 };
795 930
796 $grp 931 $grp
797} 932}
798 933
799=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 934=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
800 935
801Scans a directory (similar to C<aio_readdir>) but additionally tries to 936Scans a directory (similar to C<aio_readdir>) but additionally tries to
802efficiently separate the entries of directory C<$path> into two sets of 937efficiently separate the entries of directory C<$path> into two sets of
803names, directories you can recurse into (directories), and ones you cannot 938names, directories you can recurse into (directories), and ones you cannot
804recurse into (everything else, including symlinks to directories). 939recurse into (everything else, including symlinks to directories).
… …
835Then entries will be sorted into likely directories a non-initial dot 970Then entries will be sorted into likely directories a non-initial dot
836currently) and likely non-directories (see C<aio_readdirx>). Then every 971currently) and likely non-directories (see C<aio_readdirx>). Then every
837entry plus an appended C</.> will be C<stat>'ed, likely directories first, 972entry plus an appended C</.> will be C<stat>'ed, likely directories first,
838in order of their inode numbers. If that succeeds, it assumes that the 973in order of their inode numbers. If that succeeds, it assumes that the
839entry is a directory or a symlink to directory (which will be checked 974entry is a directory or a symlink to directory (which will be checked
840seperately). This is often faster than stat'ing the entry itself because 975separately). This is often faster than stat'ing the entry itself because
841filesystems might detect the type of the entry without reading the inode 976filesystems might detect the type of the entry without reading the inode
842data (e.g. ext2fs filetype feature), even on systems that cannot return 977data (e.g. ext2fs filetype feature), even on systems that cannot return
843the filetype information on readdir. 978the filetype information on readdir.
844 979
845If the known number of directories (link count - 2) has been reached, the 980If the known number of directories (link count - 2) has been reached, the
… …
861 996
862 my $grp = aio_group $cb; 997 my $grp = aio_group $cb;
863 998
864 $maxreq = 4 if $maxreq <= 0; 999 $maxreq = 4 if $maxreq <= 0;
865 1000
866 # stat once 1001 # get a wd object
867 aioreq_pri $pri; 1002 aioreq_pri $pri;
868 add $grp aio_stat $path, sub { 1003 add $grp aio_wd $path, sub {
1004 $_[0]
869 return $grp->result () if $_[0]; 1005 or return $grp->result ();
870 my $now = time;
871 my $hash1 = join ":", (stat _)[0,1,3,7,9];
872 1006
873 # read the directory entries 1007 my $wd = [shift, "."];
1008
1009 # stat once
874 aioreq_pri $pri; 1010 aioreq_pri $pri;
875 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1011 add $grp aio_stat $wd, sub {
876 my $entries = shift
877 or return $grp->result (); 1012 return $grp->result () if $_[0];
1013 my $now = time;
1014 my $hash1 = join ":", (stat _)[0,1,3,7,9];
878 1015
879 # stat the dir another time 1016 # read the directory entries
880 aioreq_pri $pri; 1017 aioreq_pri $pri;
1018 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
1019 my $entries = shift
1020 or return $grp->result ();
1021
1022 # stat the dir another time
1023 aioreq_pri $pri;
881 add $grp aio_stat $path, sub { 1024 add $grp aio_stat $wd, sub {
882 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1025 my $hash2 = join ":", (stat _)[0,1,3,7,9];
883 1026
884 my $ndirs; 1027 my $ndirs;
885 1028
886 # take the slow route if anything looks fishy 1029 # take the slow route if anything looks fishy
887 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1030 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
888 $ndirs = -1; 1031 $ndirs = -1;
889 } else { 1032 } else {
890 # if nlink == 2, we are finished 1033 # if nlink == 2, we are finished
891 # for non-posix-fs's, we rely on nlink < 2 1034 # for non-posix-fs's, we rely on nlink < 2
892 $ndirs = (stat _)[3] - 2 1035 $ndirs = (stat _)[3] - 2
893 or return $grp->result ([], $entries); 1036 or return $grp->result ([], $entries);
894 } 1037 }
895 1038
896 my (@dirs, @nondirs); 1039 my (@dirs, @nondirs);
897 1040
898 my $statgrp = add $grp aio_group sub { 1041 my $statgrp = add $grp aio_group sub {
899 $grp->result (\@dirs, \@nondirs); 1042 $grp->result (\@dirs, \@nondirs);
900 }; 1043 };
901 1044
902 limit $statgrp $maxreq; 1045 limit $statgrp $maxreq;
903 feed $statgrp sub { 1046 feed $statgrp sub {
904 return unless @$entries; 1047 return unless @$entries;
905 my $entry = shift @$entries; 1048 my $entry = shift @$entries;
906 1049
907 aioreq_pri $pri; 1050 aioreq_pri $pri;
1051 $wd->[1] = "$entry/.";
908 add $statgrp aio_stat "$path/$entry/.", sub { 1052 add $statgrp aio_stat $wd, sub {
909 if ($_[0] < 0) { 1053 if ($_[0] < 0) {
910 push @nondirs, $entry; 1054 push @nondirs, $entry;
911 } else { 1055 } else {
912 # need to check for real directory 1056 # need to check for real directory
913 aioreq_pri $pri; 1057 aioreq_pri $pri;
1058 $wd->[1] = $entry;
914 add $statgrp aio_lstat "$path/$entry", sub { 1059 add $statgrp aio_lstat $wd, sub {
915 if (-d _) { 1060 if (-d _) {
916 push @dirs, $entry; 1061 push @dirs, $entry;
917 1062
918 unless (--$ndirs) { 1063 unless (--$ndirs) {
919 push @nondirs, @$entries; 1064 push @nondirs, @$entries;
920 feed $statgrp; 1065 feed $statgrp;
1066 }
1067 } else {
1068 push @nondirs, $entry;
921 } 1069 }
922 } else {
923 push @nondirs, $entry;
924 } 1070 }
925 } 1071 }
926 } 1072 };
927 }; 1073 };
928 }; 1074 };
929 }; 1075 };
930 }; 1076 };
931 }; 1077 };
932 1078
933 $grp 1079 $grp
934} 1080}
935 1081
936=item aio_rmtree $path, $callback->($status) 1082=item aio_rmtree $pathname, $callback->($status)
937 1083
938Delete a directory tree starting (and including) C<$path>, return the 1084Delete a directory tree starting (and including) C<$path>, return the
939status of the final C<rmdir> only. This is a composite request that 1085status of the final C<rmdir> only. This is a composite request that
940uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1086uses C<aio_scandir> to recurse into and rmdir directories, and unlink
941everything else. 1087everything else.
… …
983callback with the fdatasync result code. 1129callback with the fdatasync result code.
984 1130
985If this call isn't available because your OS lacks it or it couldn't be 1131If this call isn't available because your OS lacks it or it couldn't be
986detected, it will be emulated by calling C<fsync> instead. 1132detected, it will be emulated by calling C<fsync> instead.
987 1133
1134=item aio_syncfs $fh, $callback->($status)
1135
1136Asynchronously call the syncfs syscall to sync the filesystem associated
1137to the given filehandle and call the callback with the syncfs result
1138code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1139errno to C<ENOSYS> nevertheless.
1140
988=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 1141=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
989 1142
990Sync the data portion of the file specified by C<$offset> and C<$length> 1143Sync the data portion of the file specified by C<$offset> and C<$length>
991to disk (but NOT the metadata), by calling the Linux-specific 1144to disk (but NOT the metadata), by calling the Linux-specific
992sync_file_range call. If sync_file_range is not available or it returns 1145sync_file_range call. If sync_file_range is not available or it returns
… …
995C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1148C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
996C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1149C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
997C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range 1150C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
998manpage for details. 1151manpage for details.
999 1152
1000=item aio_pathsync $path, $callback->($status) 1153=item aio_pathsync $pathname, $callback->($status)
1001 1154
1002This request tries to open, fsync and close the given path. This is a 1155This request tries to open, fsync and close the given path. This is a
1003composite request intended to sync directories after directory operations 1156composite request intended to sync directories after directory operations
1004(E.g. rename). This might not work on all operating systems or have any 1157(E.g. rename). This might not work on all operating systems or have any
1005specific effect, but usually it makes sure that directory changes get 1158specific effect, but usually it makes sure that directory changes get
… …
1039} 1192}
1040 1193
1041=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1194=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1042 1195
1043This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1196This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1044scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note 1197scalars (see the C<IO::AIO::mmap> function, although it also works on data
1198scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1045that the scalar must only be modified in-place while an aio operation is 1199scalar must only be modified in-place while an aio operation is pending on
1046pending on it). 1200it).
1047 1201
1048It calls the C<msync> function of your OS, if available, with the memory 1202It calls the C<msync> function of your OS, if available, with the memory
1049area starting at C<$offset> in the string and ending C<$length> bytes 1203area starting at C<$offset> in the string and ending C<$length> bytes
1050later. If C<$length> is negative, counts from the end, and if C<$length> 1204later. If C<$length> is negative, counts from the end, and if C<$length>
1051is C<undef>, then it goes till the end of the string. The flags can be 1205is C<undef>, then it goes till the end of the string. The flags can be
… …
1062as for C<aio_msync>, above, except for flags, which must be either 1216as for C<aio_msync>, above, except for flags, which must be either
1063C<0> (which reads all pages and ensures they are instantiated) or 1217C<0> (which reads all pages and ensures they are instantiated) or
1064C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1218C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1065writing an octet from it, which dirties the page). 1219writing an octet from it, which dirties the page).
1066 1220
1221=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1222
1223This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1224scalars.
1225
1226It reads in all the pages of the underlying storage into memory (if any)
1227and locks them, so they are not getting swapped/paged out or removed.
1228
1229If C<$length> is undefined, then the scalar will be locked till the end.
1230
1231On systems that do not implement C<mlock>, this function returns C<-1>
1232and sets errno to C<ENOSYS>.
1233
1234Note that the corresponding C<munlock> is synchronous and is
1235documented under L<MISCELLANEOUS FUNCTIONS>.
1236
1237Example: open a file, mmap and mlock it - both will be undone when
1238C<$data> gets destroyed.
1239
1240 open my $fh, "<", $path or die "$path: $!";
1241 my $data;
1242 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1243 aio_mlock $data; # mlock in background
1244
1245=item aio_mlockall $flags, $callback->($status)
1246
1247Calls the C<mlockall> function with the given C<$flags> (a combination of
1248C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1249
1250On systems that do not implement C<mlockall>, this function returns C<-1>
1251and sets errno to C<ENOSYS>.
1252
1253Note that the corresponding C<munlockall> is synchronous and is
1254documented under L<MISCELLANEOUS FUNCTIONS>.
1255
1256Example: asynchronously lock all current and future pages into memory.
1257
1258 aio_mlockall IO::AIO::MCL_FUTURE;
1259
1260=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1261
1262Queries the extents of the given file (by calling the Linux FIEMAP ioctl,
1263see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the
1264C<ioctl> is not available on your OS, then this rquiest will fail with
1265C<ENOSYS>.
1266
1267C<$start> is the starting offset to query extents for, C<$length> is the
1268size of the range to query - if it is C<undef>, then the whole file will
1269be queried.
1270
1271C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1272C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1273exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1274the data portion.
1275
1276C<$count> is the maximum number of extent records to return. If it is
1277C<undef>, then IO::AIO queries all extents of the file. As a very special
1278case, if it is C<0>, then the callback receives the number of extents
1279instead of the extents themselves.
1280
1281If an error occurs, the callback receives no arguments. The special
1282C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1283
1284Otherwise, the callback receives an array reference with extent
1285structures. Each extent structure is an array reference itself, with the
1286following members:
1287
1288 [$logical, $physical, $length, $flags]
1289
1290Flags is any combination of the following flag values (typically either C<0>
1291or C<IO::AIO::FIEMAP_EXTENT_LAST>):
1292
1293C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1294C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1295C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1296C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1297C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1298C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1299
1067=item aio_group $callback->(...) 1300=item aio_group $callback->(...)
1068 1301
1069This is a very special aio request: Instead of doing something, it is a 1302This is a very special aio request: Instead of doing something, it is a
1070container for other aio requests, which is useful if you want to bundle 1303container for other aio requests, which is useful if you want to bundle
1071many requests into a single, composite, request with a definite callback 1304many requests into a single, composite, request with a definite callback
… …
1107like sleep and file handle readable/writable, the overhead this creates is 1340like sleep and file handle readable/writable, the overhead this creates is
1108immense (it blocks a thread for a long time) so do not use this function 1341immense (it blocks a thread for a long time) so do not use this function
1109except to put your application under artificial I/O pressure. 1342except to put your application under artificial I/O pressure.
1110 1343
1111=back 1344=back
1345
1346
1347=head2 IO::AIO::WD - multiple working directories
1348
1349Your process only has one current working directory, which is used by all
1350threads. This makes it hard to use relative paths (some other component
1351could call C<chdir> at any time, and it is hard to control when the path
1352will be used by IO::AIO).
1353
1354One solution for this is to always use absolute paths. This usually works,
1355but can be quite slow (the kernel has to walk the whole path on every
1356access), and can also be a hassle to implement.
1357
1358Newer POSIX systems have a number of functions (openat, fdopendir,
1359futimensat and so on) that make it possible to specify working directories
1360per operation.
1361
1362For portability, and because the clowns who "designed", or shall I write,
1363perpetrated this new interface were obviously half-drunk, this abstraction
1364cannot be perfect, though.
1365
1366IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1367object. This object stores the canonicalised, absolute version of the
1368path, and on systems that allow it, also a directory file descriptor.
1369
1370Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1371or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1372object and a pathname instead (or the IO::AIO::WD object alone, which
1373gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1374IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1375to that IO::AIO::WD object.
1376
1377For example, to get a wd object for F</etc> and then stat F<passwd>
1378inside, you would write:
1379
1380 aio_wd "/etc", sub {
1381 my $etcdir = shift;
1382
1383 # although $etcdir can be undef on error, there is generally no reason
1384 # to check for errors here, as aio_stat will fail with ENOENT
1385 # when $etcdir is undef.
1386
1387 aio_stat [$etcdir, "passwd"], sub {
1388 # yay
1389 };
1390 };
1391
1392That C<aio_wd> is a request and not a normal function shows that creating
1393an IO::AIO::WD object is itself a potentially blocking operation, which is
1394why it is done asynchronously.
1395
1396To stat the directory obtained with C<aio_wd> above, one could write
1397either of the following three request calls:
1398
1399 aio_lstat "/etc" , sub { ... # pathname as normal string
1400 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1401 aio_lstat $wd , sub { ... # shorthand for the previous
1402
1403As with normal pathnames, IO::AIO keeps a copy of the working directory
1404object and the pathname string, so you could write the following without
1405causing any issues due to C<$path> getting reused:
1406
1407 my $path = [$wd, undef];
1408
1409 for my $name (qw(abc def ghi)) {
1410 $path->[1] = $name;
1411 aio_stat $path, sub {
1412 # ...
1413 };
1414 }
1415
1416There are some caveats: when directories get renamed (or deleted), the
1417pathname string doesn't change, so will point to the new directory (or
1418nowhere at all), while the directory fd, if available on the system,
1419will still point to the original directory. Most functions accepting a
1420pathname will use the directory fd on newer systems, and the string on
1421older systems. Some functions (such as realpath) will always rely on the
1422string form of the pathname.
1423
1424So this fucntionality is mainly useful to get some protection against
1425C<chdir>, to easily get an absolute path out of a relative path for future
1426reference, and to speed up doing many operations in the same directory
1427(e.g. when stat'ing all files in a directory).
1428
1429The following functions implement this working directory abstraction:
1430
1431=over 4
1432
1433=item aio_wd $pathname, $callback->($wd)
1434
1435Asynchonously canonicalise the given pathname and convert it to an
1436IO::AIO::WD object representing it. If possible and supported on the
1437system, also open a directory fd to speed up pathname resolution relative
1438to this working directory.
1439
1440If something goes wrong, then C<undef> is passwd to the callback instead
1441of a working directory object and C<$!> is set appropriately. Since
1442passing C<undef> as working directory component of a pathname fails the
1443request with C<ENOENT>, there is often no need for error checking in the
1444C<aio_wd> callback, as future requests using the value will fail in the
1445expected way.
1446
1447If this call isn't available because your OS lacks it or it couldn't be
1448detected, it will be emulated by calling C<fsync> instead.
1449
1450=item IO::AIO::CWD
1451
1452This is a compiletime constant (object) that represents the process
1453current working directory.
1454
1455Specifying this object as working directory object for a pathname is as
1456if the pathname would be specified directly, without a directory object,
1457e.g., these calls are functionally identical:
1458
1459 aio_stat "somefile", sub { ... };
1460 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1461
1462=back
1463
1112 1464
1113=head2 IO::AIO::REQ CLASS 1465=head2 IO::AIO::REQ CLASS
1114 1466
1115All non-aggregate C<aio_*> functions return an object of this class when 1467All non-aggregate C<aio_*> functions return an object of this class when
1116called in non-void context. 1468called in non-void context.
… …
1234 1586
1235Sets a feeder/generator on this group: every group can have an attached 1587Sets a feeder/generator on this group: every group can have an attached
1236generator that generates requests if idle. The idea behind this is that, 1588generator that generates requests if idle. The idea behind this is that,
1237although you could just queue as many requests as you want in a group, 1589although you could just queue as many requests as you want in a group,
1238this might starve other requests for a potentially long time. For example, 1590this might starve other requests for a potentially long time. For example,
1239C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1591C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1240delaying any later requests for a long time. 1592requests, delaying any later requests for a long time.
1241 1593
1242To avoid this, and allow incremental generation of requests, you can 1594To avoid this, and allow incremental generation of requests, you can
1243instead a group and set a feeder on it that generates those requests. The 1595instead a group and set a feeder on it that generates those requests. The
1244feed callback will be called whenever there are few enough (see C<limit>, 1596feed callback will be called whenever there are few enough (see C<limit>,
1245below) requests active in the group itself and is expected to queue more 1597below) requests active in the group itself and is expected to queue more
… …
1294 1646
1295See C<poll_cb> for an example. 1647See C<poll_cb> for an example.
1296 1648
1297=item IO::AIO::poll_cb 1649=item IO::AIO::poll_cb
1298 1650
1299Process some outstanding events on the result pipe. You have to call this 1651Process some outstanding events on the result pipe. You have to call
1300regularly. Returns C<0> if all events could be processed, or C<-1> if it 1652this regularly. Returns C<0> if all events could be processed (or there
1301returned earlier for whatever reason. Returns immediately when no events 1653were no events to process), or C<-1> if it returned earlier for whatever
1302are outstanding. The amount of events processed depends on the settings of 1654reason. Returns immediately when no events are outstanding. The amount of
1303C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1655events processed depends on the settings of C<IO::AIO::max_poll_req> and
1656C<IO::AIO::max_poll_time>.
1304 1657
1305If not all requests were processed for whatever reason, the filehandle 1658If not all requests were processed for whatever reason, the filehandle
1306will still be ready when C<poll_cb> returns, so normally you don't have to 1659will still be ready when C<poll_cb> returns, so normally you don't have to
1307do anything special to have it called later. 1660do anything special to have it called later.
1308 1661
1662Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1663ready, it can be beneficial to call this function from loops which submit
1664a lot of requests, to make sure the results get processed when they become
1665available and not just when the loop is finished and the event loop takes
1666over again. This function returns very fast when there are no outstanding
1667requests.
1668
1309Example: Install an Event watcher that automatically calls 1669Example: Install an Event watcher that automatically calls
1310IO::AIO::poll_cb with high priority (more examples can be found in the 1670IO::AIO::poll_cb with high priority (more examples can be found in the
1311SYNOPSIS section, at the top of this document): 1671SYNOPSIS section, at the top of this document):
1312 1672
1313 Event->io (fd => IO::AIO::poll_fileno, 1673 Event->io (fd => IO::AIO::poll_fileno,
1314 poll => 'r', async => 1, 1674 poll => 'r', async => 1,
1315 cb => \&IO::AIO::poll_cb); 1675 cb => \&IO::AIO::poll_cb);
1676
1677=item IO::AIO::poll_wait
1678
1679If there are any outstanding requests and none of them in the result
1680phase, wait till the result filehandle becomes ready for reading (simply
1681does a C<select> on the filehandle. This is useful if you want to
1682synchronously wait for some requests to finish).
1683
1684See C<nreqs> for an example.
1685
1686=item IO::AIO::poll
1687
1688Waits until some requests have been handled.
1689
1690Returns the number of requests processed, but is otherwise strictly
1691equivalent to:
1692
1693 IO::AIO::poll_wait, IO::AIO::poll_cb
1694
1695=item IO::AIO::flush
1696
1697Wait till all outstanding AIO requests have been handled.
1698
1699Strictly equivalent to:
1700
1701 IO::AIO::poll_wait, IO::AIO::poll_cb
1702 while IO::AIO::nreqs;
1316 1703
1317=item IO::AIO::max_poll_reqs $nreqs 1704=item IO::AIO::max_poll_reqs $nreqs
1318 1705
1319=item IO::AIO::max_poll_time $seconds 1706=item IO::AIO::max_poll_time $seconds
1320 1707
… …
1345 # use a low priority so other tasks have priority 1732 # use a low priority so other tasks have priority
1346 Event->io (fd => IO::AIO::poll_fileno, 1733 Event->io (fd => IO::AIO::poll_fileno,
1347 poll => 'r', nice => 1, 1734 poll => 'r', nice => 1,
1348 cb => &IO::AIO::poll_cb); 1735 cb => &IO::AIO::poll_cb);
1349 1736
1350=item IO::AIO::poll_wait
1351
1352If there are any outstanding requests and none of them in the result
1353phase, wait till the result filehandle becomes ready for reading (simply
1354does a C<select> on the filehandle. This is useful if you want to
1355synchronously wait for some requests to finish).
1356
1357See C<nreqs> for an example.
1358
1359=item IO::AIO::poll
1360
1361Waits until some requests have been handled.
1362
1363Returns the number of requests processed, but is otherwise strictly
1364equivalent to:
1365
1366 IO::AIO::poll_wait, IO::AIO::poll_cb
1367
1368=item IO::AIO::flush
1369
1370Wait till all outstanding AIO requests have been handled.
1371
1372Strictly equivalent to:
1373
1374 IO::AIO::poll_wait, IO::AIO::poll_cb
1375 while IO::AIO::nreqs;
1376
1377=back 1737=back
1378 1738
1379=head3 CONTROLLING THE NUMBER OF THREADS 1739=head3 CONTROLLING THE NUMBER OF THREADS
1380 1740
1381=over 1741=over
… …
1414 1774
1415Under normal circumstances you don't need to call this function. 1775Under normal circumstances you don't need to call this function.
1416 1776
1417=item IO::AIO::max_idle $nthreads 1777=item IO::AIO::max_idle $nthreads
1418 1778
1419Limit the number of threads (default: 4) that are allowed to idle (i.e., 1779Limit the number of threads (default: 4) that are allowed to idle
1420threads that did not get a request to process within 10 seconds). That 1780(i.e., threads that did not get a request to process within the idle
1421means if a thread becomes idle while C<$nthreads> other threads are also 1781timeout (default: 10 seconds). That means if a thread becomes idle while
1422idle, it will free its resources and exit. 1782C<$nthreads> other threads are also idle, it will free its resources and
1783exit.
1423 1784
1424This is useful when you allow a large number of threads (e.g. 100 or 1000) 1785This is useful when you allow a large number of threads (e.g. 100 or 1000)
1425to allow for extremely high load situations, but want to free resources 1786to allow for extremely high load situations, but want to free resources
1426under normal circumstances (1000 threads can easily consume 30MB of RAM). 1787under normal circumstances (1000 threads can easily consume 30MB of RAM).
1427 1788
1428The default is probably ok in most situations, especially if thread 1789The default is probably ok in most situations, especially if thread
1429creation is fast. If thread creation is very slow on your system you might 1790creation is fast. If thread creation is very slow on your system you might
1430want to use larger values. 1791want to use larger values.
1431 1792
1793=item IO::AIO::idle_timeout $seconds
1794
1795Sets the minimum idle timeout (default 10) after which worker threads are
1796allowed to exit. SEe C<IO::AIO::max_idle>.
1797
1432=item IO::AIO::max_outstanding $maxreqs 1798=item IO::AIO::max_outstanding $maxreqs
1799
1800Sets the maximum number of outstanding requests to C<$nreqs>. If
1801you do queue up more than this number of requests, the next call to
1802C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1803C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1804longer exceeded.
1805
1806In other words, this setting does not enforce a queue limit, but can be
1807used to make poll functions block if the limit is exceeded.
1433 1808
1434This is a very bad function to use in interactive programs because it 1809This is a very bad function to use in interactive programs because it
1435blocks, and a bad way to reduce concurrency because it is inexact: Better 1810blocks, and a bad way to reduce concurrency because it is inexact: Better
1436use an C<aio_group> together with a feed callback. 1811use an C<aio_group> together with a feed callback.
1437 1812
1438Sets the maximum number of outstanding requests to C<$nreqs>. If you 1813It's main use is in scripts without an event loop - when you want to stat
1439do queue up more than this number of requests, the next call to the 1814a lot of files, you can write somehting like this:
1440C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1441function will block until the limit is no longer exceeded.
1442 1815
1443The default value is very large, so there is no practical limit on the 1816 IO::AIO::max_outstanding 32;
1444number of outstanding requests.
1445 1817
1446You can still queue as many requests as you want. Therefore, 1818 for my $path (...) {
1447C<max_outstanding> is mainly useful in simple scripts (with low values) or 1819 aio_stat $path , ...;
1448as a stop gap to shield against fatal memory overflow (with large values). 1820 IO::AIO::poll_cb;
1821 }
1822
1823 IO::AIO::flush;
1824
1825The call to C<poll_cb> inside the loop will normally return instantly, but
1826as soon as more thna C<32> reqeusts are in-flight, it will block until
1827some requests have been handled. This keeps the loop from pushing a large
1828number of C<aio_stat> requests onto the queue.
1829
1830The default value for C<max_outstanding> is very large, so there is no
1831practical limit on the number of outstanding requests.
1449 1832
1450=back 1833=back
1451 1834
1452=head3 STATISTICAL INFORMATION 1835=head3 STATISTICAL INFORMATION
1453 1836
… …
1491 1874
1492Returns the number of bytes copied, or C<-1> on error. 1875Returns the number of bytes copied, or C<-1> on error.
1493 1876
1494=item IO::AIO::fadvise $fh, $offset, $len, $advice 1877=item IO::AIO::fadvise $fh, $offset, $len, $advice
1495 1878
1496Simply calls the C<posix_fadvise> function (see it's 1879Simply calls the C<posix_fadvise> function (see its
1497manpage for details). The following advice constants are 1880manpage for details). The following advice constants are
1498avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1881available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1499C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1882C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1500C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1883C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1501 1884
1502On systems that do not implement C<posix_fadvise>, this function returns 1885On systems that do not implement C<posix_fadvise>, this function returns
1503ENOSYS, otherwise the return value of C<posix_fadvise>. 1886ENOSYS, otherwise the return value of C<posix_fadvise>.
1504 1887
1888=item IO::AIO::madvise $scalar, $offset, $len, $advice
1889
1890Simply calls the C<posix_madvise> function (see its
1891manpage for details). The following advice constants are
1892available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1893C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1894
1895On systems that do not implement C<posix_madvise>, this function returns
1896ENOSYS, otherwise the return value of C<posix_madvise>.
1897
1898=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1899
1900Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1901$scalar (see its manpage for details). The following protect
1902constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1903C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1904
1905On systems that do not implement C<mprotect>, this function returns
1906ENOSYS, otherwise the return value of C<mprotect>.
1907
1908=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1909
1910Memory-maps a file (or anonymous memory range) and attaches it to the
1911given C<$scalar>, which will act like a string scalar.
1912
1913The only operations allowed on the scalar are C<substr>/C<vec> that don't
1914change the string length, and most read-only operations such as copying it
1915or searching it with regexes and so on.
1916
1917Anything else is unsafe and will, at best, result in memory leaks.
1918
1919The memory map associated with the C<$scalar> is automatically removed
1920when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1921C<IO::AIO::munmap> functions are called.
1922
1923This calls the C<mmap>(2) function internally. See your system's manual
1924page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1925
1926The C<$length> must be larger than zero and smaller than the actual
1927filesize.
1928
1929C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1930C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1931
1932C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1933C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1934not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1935(which is set to C<MAP_ANON> if your system only provides this
1936constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1937C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1938C<IO::AIO::MAP_NONBLOCK>
1939
1940If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1941
1942C<$offset> is the offset from the start of the file - it generally must be
1943a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1944
1945Example:
1946
1947 use Digest::MD5;
1948 use IO::AIO;
1949
1950 open my $fh, "<verybigfile"
1951 or die "$!";
1952
1953 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1954 or die "verybigfile: $!";
1955
1956 my $fast_md5 = md5 $data;
1957
1958=item IO::AIO::munmap $scalar
1959
1960Removes a previous mmap and undefines the C<$scalar>.
1961
1962=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1963
1964Calls the C<munlock> function, undoing the effects of a previous
1965C<aio_mlock> call (see its description for details).
1966
1967=item IO::AIO::munlockall
1968
1969Calls the C<munlockall> function.
1970
1971On systems that do not implement C<munlockall>, this function returns
1972ENOSYS, otherwise the return value of C<munlockall>.
1973
1974=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1975
1976Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1977C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
1978should be the file offset.
1979
1980The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
1981C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
1982C<IO::AIO::SPLICE_F_GIFT>.
1983
1984See the C<splice(2)> manpage for details.
1985
1986=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
1987
1988Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
1989description for C<IO::AIO::splice> above for details.
1990
1505=back 1991=back
1506 1992
1507=cut 1993=cut
1508 1994
1509min_parallel 8; 1995min_parallel 8;
1510 1996
1511END { flush } 1997END { flush }
1512 1998
15131; 19991;
1514 2000
2001=head1 EVENT LOOP INTEGRATION
2002
2003It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
2004automatically into many event loops:
2005
2006 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
2007 use AnyEvent::AIO;
2008
2009You can also integrate IO::AIO manually into many event loops, here are
2010some examples of how to do this:
2011
2012 # EV integration
2013 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
2014
2015 # Event integration
2016 Event->io (fd => IO::AIO::poll_fileno,
2017 poll => 'r',
2018 cb => \&IO::AIO::poll_cb);
2019
2020 # Glib/Gtk2 integration
2021 add_watch Glib::IO IO::AIO::poll_fileno,
2022 in => sub { IO::AIO::poll_cb; 1 };
2023
2024 # Tk integration
2025 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
2026 readable => \&IO::AIO::poll_cb);
2027
2028 # Danga::Socket integration
2029 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
2030 \&IO::AIO::poll_cb);
2031
1515=head2 FORK BEHAVIOUR 2032=head2 FORK BEHAVIOUR
1516 2033
1517This module should do "the right thing" when the process using it forks: 2034Usage of pthreads in a program changes the semantics of fork
2035considerably. Specifically, only async-safe functions can be called after
2036fork. Perl doesn't know about this, so in general, you cannot call fork
2037with defined behaviour in perl if pthreads are involved. IO::AIO uses
2038pthreads, so this applies, but many other extensions and (for inexplicable
2039reasons) perl itself often is linked against pthreads, so this limitation
2040applies to quite a lot of perls.
1518 2041
1519Before the fork, IO::AIO enters a quiescent state where no requests 2042This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1520can be added in other threads and no results will be processed. After 2043only works in the process that loaded it. Forking is fully supported, but
1521the fork the parent simply leaves the quiescent state and continues 2044using IO::AIO in the child is not.
1522request/result processing, while the child frees the request/result queue
1523(so that the requests started before the fork will only be handled in the
1524parent). Threads will be started on demand until the limit set in the
1525parent process has been reached again.
1526 2045
1527In short: the parent will, after a short pause, continue as if fork had 2046You might get around by not I<using> IO::AIO before (or after)
1528not been called, while the child will act as if IO::AIO has not been used 2047forking. You could also try to call the L<IO::AIO::reinit> function in the
1529yet. 2048child:
2049
2050=over 4
2051
2052=item IO::AIO::reinit
2053
2054Abandons all current requests and I/O threads and simply reinitialises all
2055data structures. This is not an operation supported by any standards, but
2056happens to work on GNU/Linux and some newer BSD systems.
2057
2058The only reasonable use for this function is to call it after forking, if
2059C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
2060the process will result in undefined behaviour. Calling it at any time
2061will also result in any undefined (by POSIX) behaviour.
2062
2063=back
1530 2064
1531=head2 MEMORY USAGE 2065=head2 MEMORY USAGE
1532 2066
1533Per-request usage: 2067Per-request usage:
1534 2068

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