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Revision 1.95 by root, Sun Nov 26 18:28:37 2006 UTC vs.
Revision 1.156 by root, Tue Jun 16 23:41:59 2009 UTC

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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);
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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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62etc.), but can also be used to easily do operations in parallel that are 65etc.), but can also be used to easily do operations in parallel that are
63normally done sequentially, e.g. stat'ing many files, which is much faster 66normally done sequentially, e.g. stat'ing many files, which is much faster
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 example 70While most of this works on all types of file descriptors (for
68sockets), using these functions on file descriptors that support 71example sockets), using these functions on file descriptors that
69nonblocking operation (again, sockets, pipes etc.) is very inefficient or 72support nonblocking operation (again, sockets, pipes etc.) is
70might not work (aio_read fails on sockets/pipes/fifos). Use an event loop 73very inefficient. Use an event loop for that (such as the L<EV>
71for that (such as the L<Event|Event> module): IO::AIO will naturally fit 74module): IO::AIO will naturally fit into such an event loop itself.
72into such an event loop itself.
73 75
74In this version, a number of threads are started that execute your 76In this version, a number of threads are started that execute your
75requests and signal their completion. You don't need thread support 77requests and signal their completion. You don't need thread support
76in 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
77to perl. In the future, this module might make use of the native aio 79to perl. In the future, this module might make use of the native aio
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79not well-supported or restricted (GNU/Linux doesn't allow them on normal 81not well-supported or restricted (GNU/Linux doesn't allow them on normal
80files currently, for example), and they would only support aio_read and 82files currently, for example), and they would only support aio_read and
81aio_write, so the remaining functionality would have to be implemented 83aio_write, so the remaining functionality would have to be implemented
82using threads anyway. 84using threads anyway.
83 85
84Although the module will work with in the presence of other (Perl-) 86Although the module will work in the presence of other (Perl-) threads,
85threads, it is currently not reentrant in any way, so use appropriate 87it is currently not reentrant in any way, so use appropriate locking
86locking yourself, always call C<poll_cb> from within the same thread, or 88yourself, always call C<poll_cb> from within the same thread, or never
87never call C<poll_cb> (or other C<aio_> functions) recursively. 89call C<poll_cb> (or other C<aio_> functions) recursively.
88 90
89=head2 EXAMPLE 91=head2 EXAMPLE
90 92
91This is a simple example that uses the Event module and loads 93This is a simple example that uses the EV module and loads
92F</etc/passwd> asynchronously: 94F</etc/passwd> asynchronously:
93 95
94 use Fcntl; 96 use Fcntl;
95 use Event; 97 use EV;
96 use IO::AIO; 98 use IO::AIO;
97 99
98 # register the IO::AIO callback with Event 100 # register the IO::AIO callback with EV
99 Event->io (fd => IO::AIO::poll_fileno, 101 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
100 poll => 'r',
101 cb => \&IO::AIO::poll_cb);
102 102
103 # queue the request to open /etc/passwd 103 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub { 104 aio_open "/etc/passwd", O_RDONLY, 0, sub {
105 my $fh = shift 105 my $fh = shift
106 or die "error while opening: $!"; 106 or die "error while opening: $!";
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118 118
119 # file contents now in $contents 119 # file contents now in $contents
120 print $contents; 120 print $contents;
121 121
122 # exit event loop and program 122 # exit event loop and program
123 Event::unloop; 123 EV::unloop;
124 }; 124 };
125 }; 125 };
126 126
127 # possibly queue up other requests, or open GUI windows, 127 # possibly queue up other requests, or open GUI windows,
128 # check for sockets etc. etc. 128 # check for sockets etc. etc.
129 129
130 # process events as long as there are some: 130 # process events as long as there are some:
131 Event::loop; 131 EV::loop;
132 132
133=head1 REQUEST ANATOMY AND LIFETIME 133=head1 REQUEST ANATOMY AND LIFETIME
134 134
135Every 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
136directly visible to Perl. 136directly visible to Perl.
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184 184
185=cut 185=cut
186 186
187package IO::AIO; 187package IO::AIO;
188 188
189use Carp ();
190
189no warnings; 191no warnings;
190use strict 'vars'; 192use strict 'vars';
191 193
192use base 'Exporter'; 194use base 'Exporter';
193 195
194BEGIN { 196BEGIN {
195 our $VERSION = '2.2'; 197 our $VERSION = '3.23';
196 198
197 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
198 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
199 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link 201 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
200 aio_move aio_copy aio_group aio_nop aio_mknod); 202 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
203 aio_rename aio_link aio_move aio_copy aio_group
204 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
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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271 aio_read $_[0], ..., sub { 279 aio_read $_[0], ..., sub {
272 ... 280 ...
273 }; 281 };
274 }; 282 };
275 283
284
276=item aioreq_nice $pri_adjust 285=item aioreq_nice $pri_adjust
277 286
278Similar to C<aioreq_pri>, but subtracts the given value from the current 287Similar to C<aioreq_pri>, but subtracts the given value from the current
279priority, so the effect is cumulative. 288priority, so the effect is cumulative.
289
280 290
281=item aio_open $pathname, $flags, $mode, $callback->($fh) 291=item aio_open $pathname, $flags, $mode, $callback->($fh)
282 292
283Asynchronously open or create a file and call the callback with a newly 293Asynchronously open or create a file and call the callback with a newly
284created filehandle for the file. 294created filehandle for the file.
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290list. They are the same as used by C<sysopen>. 300list. They are the same as used by C<sysopen>.
291 301
292Likewise, C<$mode> specifies the mode of the newly created file, if it 302Likewise, C<$mode> specifies the mode of the newly created file, if it
293didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 303didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
294except that it is mandatory (i.e. use C<0> if you don't create new files, 304except that it is mandatory (i.e. use C<0> if you don't create new files,
295and C<0666> or C<0777> if you do). 305and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
306by the umask in effect then the request is being executed, so better never
307change the umask.
296 308
297Example: 309Example:
298 310
299 aio_open "/etc/passwd", O_RDONLY, 0, sub { 311 aio_open "/etc/passwd", O_RDONLY, 0, sub {
300 if ($_[0]) { 312 if ($_[0]) {
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303 } else { 315 } else {
304 die "open failed: $!\n"; 316 die "open failed: $!\n";
305 } 317 }
306 }; 318 };
307 319
320
308=item aio_close $fh, $callback->($status) 321=item aio_close $fh, $callback->($status)
309 322
310Asynchronously close a file and call the callback with the result 323Asynchronously close a file and call the callback with the result
311code. I<WARNING:> although accepted, you should not pass in a perl 324code.
312filehandle here, as perl will likely close the file descriptor another
313time when the filehandle is destroyed. Normally, you can safely call perls
314C<close> or just let filehandles go out of scope.
315 325
316This 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
317therefore best to avoid this function. 327closing the file descriptor associated with the filehandle itself.
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
318 337
319=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 338=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
320 339
321=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 340=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
322 341
323Reads 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
324into 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<$dataoffset>
325callback without the actual number of bytes read (or -1 on error, just 344and calls the callback without the actual number of bytes read (or -1 on
326like the syscall). 345error, just like the syscall).
346
347C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
348offset plus the actual number of bytes read.
349
350If C<$offset> is undefined, then the current file descriptor offset will
351be used (and updated), otherwise the file descriptor offset will not be
352changed by these calls.
353
354If C<$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<$data>.
327 359
328The C<$data> scalar I<MUST NOT> be modified in any way while the request 360The C<$data> scalar I<MUST NOT> be modified in any way while the request
329is outstanding. Modifying it can result in segfaults or WW3 (if the 361is outstanding. Modifying it can result in segfaults or World War III (if
330necessary/optional hardware is installed). 362the necessary/optional hardware is installed).
331 363
332Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 364Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
333offset C<0> within the scalar: 365offset C<0> within the scalar:
334 366
335 aio_read $fh, 7, 15, $buffer, 0, sub { 367 aio_read $fh, 7, 15, $buffer, 0, sub {
336 $_[0] > 0 or die "read error: $!"; 368 $_[0] > 0 or die "read error: $!";
337 print "read $_[0] bytes: <$buffer>\n"; 369 print "read $_[0] bytes: <$buffer>\n";
338 }; 370 };
371
339 372
340=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 373=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
341 374
342Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 375Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
343reading at byte offset C<$in_offset>, and starts writing at the current 376reading at byte offset C<$in_offset>, and starts writing at the current
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357C<$in_fh> than are written, and there is no way to find out how many 390C<$in_fh> than are written, and there is no way to find out how many
358bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 391bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
359provides the number of bytes written to C<$out_fh>. Only if the result 392provides the number of bytes written to C<$out_fh>. Only if the result
360value equals C<$length> one can assume that C<$length> bytes have been 393value equals C<$length> one can assume that C<$length> bytes have been
361read. 394read.
395
362 396
363=item aio_readahead $fh,$offset,$length, $callback->($retval) 397=item aio_readahead $fh,$offset,$length, $callback->($retval)
364 398
365C<aio_readahead> populates the page cache with data from a file so that 399C<aio_readahead> populates the page cache with data from a file so that
366subsequent reads from that file will not block on disk I/O. The C<$offset> 400subsequent reads from that file will not block on disk I/O. The C<$offset>
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372file. The current file offset of the file is left unchanged. 406file. The current file offset of the file is left unchanged.
373 407
374If that syscall doesn't exist (likely if your OS isn't Linux) it will be 408If that syscall doesn't exist (likely if your OS isn't Linux) it will be
375emulated by simply reading the data, which would have a similar effect. 409emulated by simply reading the data, which would have a similar effect.
376 410
411
377=item aio_stat $fh_or_path, $callback->($status) 412=item aio_stat $fh_or_path, $callback->($status)
378 413
379=item aio_lstat $fh, $callback->($status) 414=item aio_lstat $fh, $callback->($status)
380 415
381Works like perl's C<stat> or C<lstat> in void context. The callback will 416Works like perl's C<stat> or C<lstat> in void context. The callback will
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394 aio_stat "/etc/passwd", sub { 429 aio_stat "/etc/passwd", sub {
395 $_[0] and die "stat failed: $!"; 430 $_[0] and die "stat failed: $!";
396 print "size is ", -s _, "\n"; 431 print "size is ", -s _, "\n";
397 }; 432 };
398 433
434
435=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
436
437Works like perl's C<utime> function (including the special case of $atime
438and $mtime being undef). Fractional times are supported if the underlying
439syscalls support them.
440
441When called with a pathname, uses utimes(2) if available, otherwise
442utime(2). If called on a file descriptor, uses futimes(2) if available,
443otherwise returns ENOSYS, so this is not portable.
444
445Examples:
446
447 # set atime and mtime to current time (basically touch(1)):
448 aio_utime "path", undef, undef;
449 # set atime to current time and mtime to beginning of the epoch:
450 aio_utime "path", time, undef; # undef==0
451
452
453=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
454
455Works like perl's C<chown> function, except that C<undef> for either $uid
456or $gid is being interpreted as "do not change" (but -1 can also be used).
457
458Examples:
459
460 # same as "chown root path" in the shell:
461 aio_chown "path", 0, -1;
462 # same as above:
463 aio_chown "path", 0, undef;
464
465
466=item aio_truncate $fh_or_path, $offset, $callback->($status)
467
468Works like truncate(2) or ftruncate(2).
469
470
471=item aio_chmod $fh_or_path, $mode, $callback->($status)
472
473Works like perl's C<chmod> function.
474
475
399=item aio_unlink $pathname, $callback->($status) 476=item aio_unlink $pathname, $callback->($status)
400 477
401Asynchronously unlink (delete) a file and call the callback with the 478Asynchronously unlink (delete) a file and call the callback with the
402result code. 479result code.
403 480
481
404=item aio_mknod $path, $mode, $dev, $callback->($status) 482=item aio_mknod $path, $mode, $dev, $callback->($status)
405 483
406[EXPERIMENTAL] 484[EXPERIMENTAL]
407 485
408Asynchronously create a device node (or fifo). See mknod(2). 486Asynchronously create a device node (or fifo). See mknod(2).
409 487
410The only (POSIX-) portable way of calling this function is: 488The only (POSIX-) portable way of calling this function is:
411 489
412 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 490 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
491
413 492
414=item aio_link $srcpath, $dstpath, $callback->($status) 493=item aio_link $srcpath, $dstpath, $callback->($status)
415 494
416Asynchronously create a new link to the existing object at C<$srcpath> at 495Asynchronously create a new link to the existing object at C<$srcpath> at
417the path C<$dstpath> and call the callback with the result code. 496the path C<$dstpath> and call the callback with the result code.
418 497
498
419=item aio_symlink $srcpath, $dstpath, $callback->($status) 499=item aio_symlink $srcpath, $dstpath, $callback->($status)
420 500
421Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 501Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
422the path C<$dstpath> and call the callback with the result code. 502the path C<$dstpath> and call the callback with the result code.
503
423 504
424=item aio_readlink $path, $callback->($link) 505=item aio_readlink $path, $callback->($link)
425 506
426Asynchronously read the symlink specified by C<$path> and pass it to 507Asynchronously read the symlink specified by C<$path> and pass it to
427the callback. If an error occurs, nothing or undef gets passed to the 508the callback. If an error occurs, nothing or undef gets passed to the
428callback. 509callback.
429 510
511
430=item aio_rename $srcpath, $dstpath, $callback->($status) 512=item aio_rename $srcpath, $dstpath, $callback->($status)
431 513
432Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 514Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
433rename(2) and call the callback with the result code. 515rename(2) and call the callback with the result code.
434 516
517
518=item aio_mkdir $pathname, $mode, $callback->($status)
519
520Asynchronously mkdir (create) a directory and call the callback with
521the result code. C<$mode> will be modified by the umask at the time the
522request is executed, so do not change your umask.
523
524
435=item aio_rmdir $pathname, $callback->($status) 525=item aio_rmdir $pathname, $callback->($status)
436 526
437Asynchronously rmdir (delete) a directory and call the callback with the 527Asynchronously rmdir (delete) a directory and call the callback with the
438result code. 528result code.
529
439 530
440=item aio_readdir $pathname, $callback->($entries) 531=item aio_readdir $pathname, $callback->($entries)
441 532
442Unlike 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
443directory (i.e. opendir + readdir + closedir). The entries will not be 534directory (i.e. opendir + readdir + closedir). The entries will not be
444sorted, and will B<NOT> include the C<.> and C<..> entries. 535sorted, and will B<NOT> include the C<.> and C<..> entries.
445 536
446The 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
447with 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
605
606
607=item aio_load $path, $data, $callback->($status)
608
609This is a composite request that tries to fully load the given file into
610memory. Status is the same as with aio_read.
611
612=cut
613
614sub aio_load($$;$) {
615 my ($path, undef, $cb) = @_;
616 my $data = \$_[1];
617
618 my $pri = aioreq_pri;
619 my $grp = aio_group $cb;
620
621 aioreq_pri $pri;
622 add $grp aio_open $path, O_RDONLY, 0, sub {
623 my $fh = shift
624 or return $grp->result (-1);
625
626 aioreq_pri $pri;
627 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
628 $grp->result ($_[0]);
629 };
630 };
631
632 $grp
633}
448 634
449=item aio_copy $srcpath, $dstpath, $callback->($status) 635=item aio_copy $srcpath, $dstpath, $callback->($status)
450 636
451Try 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
452destination) from C<$srcpath> to C<$dstpath> and call the callback with 638destination) from C<$srcpath> to C<$dstpath> and call the callback with
453the C<0> (error) or C<-1> ok. 639the C<0> (error) or C<-1> ok.
454 640
455This is a composite request that it creates the destination file with 641This is a composite request that creates the destination file with
456mode 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
457C<aio_sendfile>, followed by restoring atime, mtime, access mode and 643C<aio_sendfile>, followed by restoring atime, mtime, access mode and
458uid/gid, in that order. 644uid/gid, in that order.
459 645
460If an error occurs, the partial destination file will be unlinked, if 646If an error occurs, the partial destination file will be unlinked, if
… …
462errors are being ignored. 648errors are being ignored.
463 649
464=cut 650=cut
465 651
466sub aio_copy($$;$) { 652sub aio_copy($$;$) {
467 aio_block {
468 my ($src, $dst, $cb) = @_; 653 my ($src, $dst, $cb) = @_;
469 654
470 my $pri = aioreq_pri; 655 my $pri = aioreq_pri;
471 my $grp = aio_group $cb; 656 my $grp = aio_group $cb;
472 657
473 aioreq_pri $pri; 658 aioreq_pri $pri;
474 add $grp aio_open $src, O_RDONLY, 0, sub { 659 add $grp aio_open $src, O_RDONLY, 0, sub {
475 if (my $src_fh = $_[0]) { 660 if (my $src_fh = $_[0]) {
476 my @stat = stat $src_fh; 661 my @stat = stat $src_fh; # hmm, might bock over nfs?
477 662
478 aioreq_pri $pri; 663 aioreq_pri $pri;
479 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 {
480 if (my $dst_fh = $_[0]) { 665 if (my $dst_fh = $_[0]) {
481 aioreq_pri $pri; 666 aioreq_pri $pri;
482 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 667 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
483 if ($_[0] == $stat[7]) { 668 if ($_[0] == $stat[7]) {
484 $grp->result (0); 669 $grp->result (0);
485 close $src_fh; 670 close $src_fh;
486 671
487 # those should not normally block. should. should.
488 utime $stat[8], $stat[9], $dst;
489 chmod $stat[2] & 07777, $dst_fh;
490 chown $stat[4], $stat[5], $dst_fh;
491 close $dst_fh;
492 } else { 672 my $ch = sub {
493 $grp->result (-1);
494 close $src_fh;
495 close $dst_fh;
496
497 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;
498 add $grp aio_unlink $dst; 678 add $grp aio_close $dst_fh;
679 }
680 };
499 } 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;
500 }; 699 }
501 } else {
502 $grp->result (-1);
503 } 700 };
701 } else {
702 $grp->result (-1);
504 }, 703 }
505
506 } else {
507 $grp->result (-1);
508 } 704 },
705
706 } else {
707 $grp->result (-1);
509 }; 708 }
510
511 $grp
512 } 709 };
710
711 $grp
513} 712}
514 713
515=item aio_move $srcpath, $dstpath, $callback->($status) 714=item aio_move $srcpath, $dstpath, $callback->($status)
516 715
517Try 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
518destination) from C<$srcpath> to C<$dstpath> and call the callback with 717destination) from C<$srcpath> to C<$dstpath> and call the callback with
519the C<0> (error) or C<-1> ok. 718the C<0> (error) or C<-1> ok.
520 719
521This 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
522rename 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
523that is successful, unlinking the C<$srcpath>. 722that is successful, unlinks the C<$srcpath>.
524 723
525=cut 724=cut
526 725
527sub aio_move($$;$) { 726sub aio_move($$;$) {
528 aio_block {
529 my ($src, $dst, $cb) = @_; 727 my ($src, $dst, $cb) = @_;
530 728
531 my $pri = aioreq_pri; 729 my $pri = aioreq_pri;
532 my $grp = aio_group $cb; 730 my $grp = aio_group $cb;
533 731
534 aioreq_pri $pri; 732 aioreq_pri $pri;
535 add $grp aio_rename $src, $dst, sub { 733 add $grp aio_rename $src, $dst, sub {
536 if ($_[0] && $! == EXDEV) { 734 if ($_[0] && $! == EXDEV) {
537 aioreq_pri $pri; 735 aioreq_pri $pri;
538 add $grp aio_copy $src, $dst, sub { 736 add $grp aio_copy $src, $dst, sub {
539 $grp->result ($_[0]);
540
541 if (!$_[0]) {
542 aioreq_pri $pri;
543 add $grp aio_unlink $src;
544 }
545 };
546 } else {
547 $grp->result ($_[0]); 737 $grp->result ($_[0]);
738
739 if (!$_[0]) {
740 aioreq_pri $pri;
741 add $grp aio_unlink $src;
742 }
548 } 743 };
744 } else {
745 $grp->result ($_[0]);
549 }; 746 }
550
551 $grp
552 } 747 };
748
749 $grp
553} 750}
554 751
555=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 752=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
556 753
557Scans a directory (similar to C<aio_readdir>) but additionally tries to 754Scans a directory (similar to C<aio_readdir>) but additionally tries to
… …
577 774
578Implementation notes. 775Implementation notes.
579 776
580The 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.
581 778
779If readdir returns file type information, then this is used directly to
780find directories.
781
582After reading the directory, the modification time, size etc. of the 782Otherwise, after reading the directory, the modification time, size etc.
583directory 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
584isn'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
585entries are directories (if >= 2). Otherwise, no knowledge of the number 785how many entries are directories (if >= 2). Otherwise, no knowledge of the
586of subdirectories will be assumed. 786number of subdirectories will be assumed.
587 787
588Then entries will be sorted into likely directories (everything without 788Then entries will be sorted into likely directories a non-initial dot
589a non-initial dot currently) and likely non-directories (everything 789currently) and likely non-directories (see C<aio_readdirx>). Then every
590else). 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,
591likely directories first. If that succeeds, it assumes that the entry 791in order of their inode numbers. If that succeeds, it assumes that the
592is a directory or a symlink to directory (which will be checked 792entry is a directory or a symlink to directory (which will be checked
593seperately). This is often faster than stat'ing the entry itself because 793seperately). This is often faster than stat'ing the entry itself because
594filesystems might detect the type of the entry without reading the inode 794filesystems might detect the type of the entry without reading the inode
595data (e.g. ext2fs filetype feature). 795data (e.g. ext2fs filetype feature), even on systems that cannot return
796the filetype information on readdir.
596 797
597If 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
598rest of the entries is assumed to be non-directories. 799rest of the entries is assumed to be non-directories.
599 800
600This only works with certainty on POSIX (= UNIX) filesystems, which 801This only works with certainty on POSIX (= UNIX) filesystems, which
… …
604as those tend to return 0 or 1 as link counts, which disables the 805as those tend to return 0 or 1 as link counts, which disables the
605directory counting heuristic. 806directory counting heuristic.
606 807
607=cut 808=cut
608 809
609sub aio_scandir($$$) { 810sub aio_scandir($$;$) {
610 aio_block {
611 my ($path, $maxreq, $cb) = @_; 811 my ($path, $maxreq, $cb) = @_;
612 812
613 my $pri = aioreq_pri; 813 my $pri = aioreq_pri;
614 814
615 my $grp = aio_group $cb; 815 my $grp = aio_group $cb;
616 816
617 $maxreq = 4 if $maxreq <= 0; 817 $maxreq = 4 if $maxreq <= 0;
618 818
619 # 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
620 aioreq_pri $pri; 827 aioreq_pri $pri;
621 add $grp aio_stat $path, sub { 828 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
829 my $entries = shift
622 return $grp->result () if $_[0]; 830 or return $grp->result ();
623 my $now = time;
624 my $hash1 = join ":", (stat _)[0,1,3,7,9];
625 831
626 # read the directory entries 832 # stat the dir another time
627 aioreq_pri $pri; 833 aioreq_pri $pri;
628 add $grp aio_readdir $path, sub {
629 my $entries = shift
630 or return $grp->result ();
631
632 # stat the dir another time
633 aioreq_pri $pri;
634 add $grp aio_stat $path, sub { 834 add $grp aio_stat $path, sub {
635 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 835 my $hash2 = join ":", (stat _)[0,1,3,7,9];
636 836
637 my $ndirs; 837 my $ndirs;
638 838
639 # take the slow route if anything looks fishy 839 # take the slow route if anything looks fishy
640 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 840 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
641 $ndirs = -1; 841 $ndirs = -1;
642 } else { 842 } else {
643 # if nlink == 2, we are finished 843 # if nlink == 2, we are finished
644 # on non-posix-fs's, we rely on nlink < 2 844 # for non-posix-fs's, we rely on nlink < 2
645 $ndirs = (stat _)[3] - 2 845 $ndirs = (stat _)[3] - 2
646 or return $grp->result ([], $entries); 846 or return $grp->result ([], $entries);
647 } 847 }
648 848
649 # sort into likely dirs and likely nondirs
650 # dirs == files without ".", short entries first
651 $entries = [map $_->[0],
652 sort { $b->[1] cmp $a->[1] }
653 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
654 @$entries];
655
656 my (@dirs, @nondirs); 849 my (@dirs, @nondirs);
657 850
658 my $statgrp = add $grp aio_group sub { 851 my $statgrp = add $grp aio_group sub {
659 $grp->result (\@dirs, \@nondirs); 852 $grp->result (\@dirs, \@nondirs);
660 }; 853 };
661 854
662 limit $statgrp $maxreq; 855 limit $statgrp $maxreq;
663 feed $statgrp sub { 856 feed $statgrp sub {
664 return unless @$entries; 857 return unless @$entries;
665 my $entry = pop @$entries; 858 my $entry = shift @$entries;
666 859
667 aioreq_pri $pri; 860 aioreq_pri $pri;
668 add $statgrp aio_stat "$path/$entry/.", sub { 861 add $statgrp aio_stat "$path/$entry/.", sub {
669 if ($_[0] < 0) { 862 if ($_[0] < 0) {
670 push @nondirs, $entry; 863 push @nondirs, $entry;
671 } else { 864 } else {
672 # need to check for real directory 865 # need to check for real directory
673 aioreq_pri $pri; 866 aioreq_pri $pri;
674 add $statgrp aio_lstat "$path/$entry", sub { 867 add $statgrp aio_lstat "$path/$entry", sub {
675 if (-d _) { 868 if (-d _) {
676 push @dirs, $entry; 869 push @dirs, $entry;
677 870
678 unless (--$ndirs) { 871 unless (--$ndirs) {
679 push @nondirs, @$entries; 872 push @nondirs, @$entries;
680 feed $statgrp; 873 feed $statgrp;
681 }
682 } else {
683 push @nondirs, $entry;
684 } 874 }
875 } else {
876 push @nondirs, $entry;
685 } 877 }
686 } 878 }
687 }; 879 }
688 }; 880 };
689 }; 881 };
690 }; 882 };
691 }; 883 };
692
693 $grp
694 } 884 };
885
886 $grp
695} 887}
888
889=item aio_rmtree $path, $callback->($status)
890
891Delete a directory tree starting (and including) C<$path>, return the
892status of the final C<rmdir> only. This is a composite request that
893uses C<aio_scandir> to recurse into and rmdir directories, and unlink
894everything else.
895
896=cut
897
898sub aio_rmtree;
899sub aio_rmtree($;$) {
900 my ($path, $cb) = @_;
901
902 my $pri = aioreq_pri;
903 my $grp = aio_group $cb;
904
905 aioreq_pri $pri;
906 add $grp aio_scandir $path, 0, sub {
907 my ($dirs, $nondirs) = @_;
908
909 my $dirgrp = aio_group sub {
910 add $grp aio_rmdir $path, sub {
911 $grp->result ($_[0]);
912 };
913 };
914
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;
919 };
920
921 $grp
922}
923
924=item aio_sync $callback->($status)
925
926Asynchronously call sync and call the callback when finished.
696 927
697=item aio_fsync $fh, $callback->($status) 928=item aio_fsync $fh, $callback->($status)
698 929
699Asynchronously call fsync on the given filehandle and call the callback 930Asynchronously call fsync on the given filehandle and call the callback
700with the fsync result code. 931with the fsync result code.
… …
704Asynchronously call fdatasync on the given filehandle and call the 935Asynchronously call fdatasync on the given filehandle and call the
705callback with the fdatasync result code. 936callback with the fdatasync result code.
706 937
707If 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
708detected, 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}
709 990
710=item aio_group $callback->(...) 991=item aio_group $callback->(...)
711 992
712This 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
713container 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
… …
763=item cancel $req 1044=item cancel $req
764 1045
765Cancels the request, if possible. Has the effect of skipping execution 1046Cancels the request, if possible. Has the effect of skipping execution
766when entering the B<execute> state and skipping calling the callback when 1047when entering the B<execute> state and skipping calling the callback when
767entering the the B<result> state, but will leave the request otherwise 1048entering the the B<result> state, but will leave the request otherwise
768untouched. That means that requests that currently execute will not be 1049untouched (with the exception of readdir). That means that requests that
769stopped 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.
770 1052
771=item cb $req $callback->(...) 1053=item cb $req $callback->(...)
772 1054
773Replace (or simply set) the callback registered to the request. 1055Replace (or simply set) the callback registered to the request.
774 1056
… …
825Their lifetime, simplified, looks like this: when they are empty, they 1107Their lifetime, simplified, looks like this: when they are empty, they
826will 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
827C<done> state, they will also finish. Otherwise they will continue to 1109C<done> state, they will also finish. Otherwise they will continue to
828exist. 1110exist.
829 1111
830That 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
831in 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
832group. 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
833itself finish. 1115further requests to the group. And only when all those requests have
1116finished will the the group itself finish.
834 1117
835=over 4 1118=over 4
836 1119
837=item add $grp ... 1120=item add $grp ...
838 1121
… …
850itself. 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.
851 1134
852=item $grp->result (...) 1135=item $grp->result (...)
853 1136
854Set 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
855subrequests have finished and set thre groups errno to the current value 1138subrequests have finished and set the groups errno to the current value
856of 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,
857no argument will be passed and errno is zero. 1140no argument will be passed and errno is zero.
858 1141
859=item $grp->errno ([$errno]) 1142=item $grp->errno ([$errno])
860 1143
… …
871=item feed $grp $callback->($grp) 1154=item feed $grp $callback->($grp)
872 1155
873Sets 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
874generator that generates requests if idle. The idea behind this is that, 1157generator that generates requests if idle. The idea behind this is that,
875although 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,
876this might starve other requests for a potentially long time. For 1159this might starve other requests for a potentially long time. For example,
877example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1160C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
878requests, delaying any later requests for a long time. 1161delaying any later requests for a long time.
879 1162
880To avoid this, and allow incremental generation of requests, you can 1163To avoid this, and allow incremental generation of requests, you can
881instead 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
882feed 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>,
883below) 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
… …
887not impose any limits). 1170not impose any limits).
888 1171
889If 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
890automatically removed from the group. 1173automatically removed from the group.
891 1174
892If 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.
893 1177
894Example: 1178Example:
895 1179
896 # 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:
897 1181
… …
909Sets 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
910the group contains less than this many requests. 1194the group contains less than this many requests.
911 1195
912Setting the limit to C<0> will pause the feeding process. 1196Setting the limit to C<0> will pause the feeding process.
913 1197
1198The default value for the limit is C<0>, but note that setting a feeder
1199automatically bumps it up to C<2>.
1200
914=back 1201=back
915 1202
916=head2 SUPPORT FUNCTIONS 1203=head2 SUPPORT FUNCTIONS
917 1204
918=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1205=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
… …
920=over 4 1207=over 4
921 1208
922=item $fileno = IO::AIO::poll_fileno 1209=item $fileno = IO::AIO::poll_fileno
923 1210
924Return the I<request result pipe file descriptor>. This filehandle must be 1211Return the I<request result pipe file descriptor>. This filehandle must be
925polled 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,
926select, 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
927to call C<poll_cb> to check the results. 1214you have to call C<poll_cb> to check the results.
928 1215
929See C<poll_cb> for an example. 1216See C<poll_cb> for an example.
930 1217
931=item IO::AIO::poll_cb 1218=item IO::AIO::poll_cb
932 1219
933Process 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
934regularly. 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
935when no events are outstanding. The amount of events processed depends on 1223are outstanding. The amount of events processed depends on the settings of
936the 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>.
937 1225
938If not all requests were processed for whatever reason, the filehandle 1226If not all requests were processed for whatever reason, the filehandle
939will 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.
940 1229
941Example: Install an Event watcher that automatically calls 1230Example: Install an Event watcher that automatically calls
942IO::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):
943 1233
944 Event->io (fd => IO::AIO::poll_fileno, 1234 Event->io (fd => IO::AIO::poll_fileno,
945 poll => 'r', async => 1, 1235 poll => 'r', async => 1,
946 cb => \&IO::AIO::poll_cb); 1236 cb => \&IO::AIO::poll_cb);
947 1237
… …
1003Strictly equivalent to: 1293Strictly equivalent to:
1004 1294
1005 IO::AIO::poll_wait, IO::AIO::poll_cb 1295 IO::AIO::poll_wait, IO::AIO::poll_cb
1006 while IO::AIO::nreqs; 1296 while IO::AIO::nreqs;
1007 1297
1298=back
1299
1008=head3 CONTROLLING THE NUMBER OF THREADS 1300=head3 CONTROLLING THE NUMBER OF THREADS
1301
1302=over
1009 1303
1010=item IO::AIO::min_parallel $nthreads 1304=item IO::AIO::min_parallel $nthreads
1011 1305
1012Set the minimum number of AIO threads to C<$nthreads>. The current 1306Set the minimum number of AIO threads to C<$nthreads>. The current
1013default is C<8>, which means eight asynchronous operations can execute 1307default is C<8>, which means eight asynchronous operations can execute
… …
1054 1348
1055The default is probably ok in most situations, especially if thread 1349The default is probably ok in most situations, especially if thread
1056creation 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
1057want to use larger values. 1351want to use larger values.
1058 1352
1059=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1353=item IO::AIO::max_outstanding $maxreqs
1060 1354
1061This is a very bad function to use in interactive programs because it 1355This is a very bad function to use in interactive programs because it
1062blocks, and a bad way to reduce concurrency because it is inexact: Better 1356blocks, and a bad way to reduce concurrency because it is inexact: Better
1063use an C<aio_group> together with a feed callback. 1357use an C<aio_group> together with a feed callback.
1064 1358
1065Sets the maximum number of outstanding requests to C<$nreqs>. If you 1359Sets the maximum number of outstanding requests to C<$nreqs>. If you
1066to 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
1067C<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>)
1068function will block until the limit is no longer exceeded. 1362function will block until the limit is no longer exceeded.
1069 1363
1070The 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
1071number of outstanding requests. 1365number of outstanding requests.
1072 1366
1073You can still queue as many requests as you want. Therefore, 1367You can still queue as many requests as you want. Therefore,
1074C<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
1075as 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).
1076 1370
1371=back
1372
1077=head3 STATISTICAL INFORMATION 1373=head3 STATISTICAL INFORMATION
1374
1375=over
1078 1376
1079=item IO::AIO::nreqs 1377=item IO::AIO::nreqs
1080 1378
1081Returns the number of requests currently in the ready, execute or pending 1379Returns the number of requests currently in the ready, execute or pending
1082states (i.e. for which their callback has not been invoked yet). 1380states (i.e. for which their callback has not been invoked yet).
… …
1097but not yet processed by poll_cb). 1395but not yet processed by poll_cb).
1098 1396
1099=back 1397=back
1100 1398
1101=cut 1399=cut
1102
1103# support function to convert a fd into a perl filehandle
1104sub _fd2fh {
1105 return undef if $_[0] < 0;
1106
1107 # try to generate nice filehandles
1108 my $sym = "IO::AIO::fd#$_[0]";
1109 local *$sym;
1110
1111 open *$sym, "+<&=$_[0]" # usually works under any unix
1112 or open *$sym, "<&=$_[0]" # cygwin needs this
1113 or open *$sym, ">&=$_[0]" # or this
1114 or return undef;
1115
1116 *$sym
1117}
1118 1400
1119min_parallel 8; 1401min_parallel 8;
1120 1402
1121END { flush } 1403END { flush }
1122 1404
… …
1146bytes of memory. In addition, stat requests need a stat buffer (possibly 1428bytes of memory. In addition, stat requests need a stat buffer (possibly
1147a 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
1148scalars 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
1149will consume memory till the request has entered the done state. 1431will consume memory till the request has entered the done state.
1150 1432
1151This 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
1152problem. 1434problem.
1153 1435
1154Per-thread usage: 1436Per-thread usage:
1155 1437
1156In the execution phase, some aio requests require more memory for 1438In the execution phase, some aio requests require more memory for
… …
1161 1443
1162Known bugs will be fixed in the next release. 1444Known bugs will be fixed in the next release.
1163 1445
1164=head1 SEE ALSO 1446=head1 SEE ALSO
1165 1447
1166L<Coro::AIO>. 1448L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1449more natural syntax.
1167 1450
1168=head1 AUTHOR 1451=head1 AUTHOR
1169 1452
1170 Marc Lehmann <schmorp@schmorp.de> 1453 Marc Lehmann <schmorp@schmorp.de>
1171 http://home.schmorp.de/ 1454 http://home.schmorp.de/

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