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Revision 1.77 by root, Wed Oct 25 17:57:30 2006 UTC vs.
Revision 1.107 by root, Fri Jun 1 05:52:59 2007 UTC

… …
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", O_RDONLY, 0, sub {
10 my ($fh) = @_; 10 my $fh = shift
11 or die "/etc/passwd: $!";
11 ... 12 ...
12 }; 13 };
13 14
14 aio_unlink "/tmp/file", sub { }; 15 aio_unlink "/tmp/file", sub { };
15 16
… …
50 51
51=head1 DESCRIPTION 52=head1 DESCRIPTION
52 53
53This module implements asynchronous I/O using whatever means your 54This module implements asynchronous I/O using whatever means your
54operating system supports. 55operating system supports.
56
57Asynchronous means that operations that can normally block your program
58(e.g. reading from disk) will be done asynchronously: the operation
59will still block, but you can do something else in the meantime. This
60is extremely useful for programs that need to stay interactive even
61when doing heavy I/O (GUI programs, high performance network servers
62etc.), 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
64on a RAID volume or over NFS when you do a number of stat operations
65concurrently.
66
67While most of this works on all types of file descriptors (for example
68sockets), using these functions on file descriptors that support
69nonblocking operation (again, sockets, pipes etc.) is very inefficient or
70might not work (aio_read fails on sockets/pipes/fifos). Use an event loop
71for that (such as the L<Event|Event> module): IO::AIO will naturally fit
72into such an event loop itself.
55 73
56In this version, a number of threads are started that execute your 74In this version, a number of threads are started that execute your
57requests and signal their completion. You don't need thread support 75requests and signal their completion. You don't need thread support
58in perl, and the threads created by this module will not be visible 76in perl, and the threads created by this module will not be visible
59to perl. In the future, this module might make use of the native aio 77to perl. In the future, this module might make use of the native aio
60functions available on many operating systems. However, they are often 78functions available on many operating systems. However, they are often
61not well-supported or restricted (Linux doesn't allow them on normal 79not well-supported or restricted (GNU/Linux doesn't allow them on normal
62files currently, for example), and they would only support aio_read and 80files currently, for example), and they would only support aio_read and
63aio_write, so the remaining functionality would have to be implemented 81aio_write, so the remaining functionality would have to be implemented
64using threads anyway. 82using threads anyway.
65 83
66Although the module will work with in the presence of other (Perl-) 84Although the module will work with in the presence of other (Perl-)
67threads, it is currently not reentrant in any way, so use appropriate 85threads, it is currently not reentrant in any way, so use appropriate
68locking yourself, always call C<poll_cb> from within the same thread, or 86locking yourself, always call C<poll_cb> from within the same thread, or
69never call C<poll_cb> (or other C<aio_> functions) recursively. 87never call C<poll_cb> (or other C<aio_> functions) recursively.
70 88
89=head2 EXAMPLE
90
91This is a simple example that uses the Event module and loads
92F</etc/passwd> asynchronously:
93
94 use Fcntl;
95 use Event;
96 use IO::AIO;
97
98 # register the IO::AIO callback with Event
99 Event->io (fd => IO::AIO::poll_fileno,
100 poll => 'r',
101 cb => \&IO::AIO::poll_cb);
102
103 # queue the request to open /etc/passwd
104 aio_open "/etc/passwd", O_RDONLY, 0, sub {
105 my $fh = shift
106 or die "error while opening: $!";
107
108 # stat'ing filehandles is generally non-blocking
109 my $size = -s $fh;
110
111 # queue a request to read the file
112 my $contents;
113 aio_read $fh, 0, $size, $contents, 0, sub {
114 $_[0] == $size
115 or die "short read: $!";
116
117 close $fh;
118
119 # file contents now in $contents
120 print $contents;
121
122 # exit event loop and program
123 Event::unloop;
124 };
125 };
126
127 # possibly queue up other requests, or open GUI windows,
128 # check for sockets etc. etc.
129
130 # process events as long as there are some:
131 Event::loop;
132
71=head1 REQUEST ANATOMY AND LIFETIME 133=head1 REQUEST ANATOMY AND LIFETIME
72 134
73Every 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
74directly visible to Perl. 136directly visible to Perl.
75 137
… …
116Request has reached the end of its lifetime and holds no resources anymore 178Request has reached the end of its lifetime and holds no resources anymore
117(except possibly for the Perl object, but its connection to the actual 179(except possibly for the Perl object, but its connection to the actual
118aio request is severed and calling its methods will either do nothing or 180aio request is severed and calling its methods will either do nothing or
119result in a runtime error). 181result in a runtime error).
120 182
183=back
184
121=cut 185=cut
122 186
123package IO::AIO; 187package IO::AIO;
124 188
125no warnings; 189no warnings;
126use strict 'vars'; 190use strict 'vars';
127 191
128use base 'Exporter'; 192use base 'Exporter';
129 193
130BEGIN { 194BEGIN {
131 our $VERSION = '2.0'; 195 our $VERSION = '2.4';
132 196
133 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 197 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
134 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 198 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
135 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 199 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
136 aio_group aio_nop); 200 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
201 aio_chown aio_chmod aio_utime);
137 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 202 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 203 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139 min_parallel max_parallel nreqs); 204 min_parallel max_parallel max_idle
205 nreqs nready npending nthreads
206 max_poll_time max_poll_reqs);
140 207
141 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 208 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142 209
143 require XSLoader; 210 require XSLoader;
144 XSLoader::load ("IO::AIO", $VERSION); 211 XSLoader::load ("IO::AIO", $VERSION);
145} 212}
146 213
147=head1 FUNCTIONS 214=head1 FUNCTIONS
148 215
149=head2 AIO FUNCTIONS 216=head2 AIO REQUEST FUNCTIONS
150 217
151All the C<aio_*> calls are more or less thin wrappers around the syscall 218All the C<aio_*> calls are more or less thin wrappers around the syscall
152with the same name (sans C<aio_>). The arguments are similar or identical, 219with the same name (sans C<aio_>). The arguments are similar or identical,
153and they all accept an additional (and optional) C<$callback> argument 220and they all accept an additional (and optional) C<$callback> argument
154which must be a code reference. This code reference will get called with 221which must be a code reference. This code reference will get called with
… …
157syscall has been executed asynchronously. 224syscall has been executed asynchronously.
158 225
159All functions expecting a filehandle keep a copy of the filehandle 226All functions expecting a filehandle keep a copy of the filehandle
160internally until the request has finished. 227internally until the request has finished.
161 228
162All requests return objects of type L<IO::AIO::REQ> that allow further 229All functions return request objects of type L<IO::AIO::REQ> that allow
163manipulation of those requests while they are in-flight. 230further manipulation of those requests while they are in-flight.
164 231
165The pathnames you pass to these routines I<must> be absolute and 232The pathnames you pass to these routines I<must> be absolute and
166encoded in byte form. The reason for the former is that at the time the 233encoded as octets. The reason for the former is that at the time the
167request is being executed, the current working directory could have 234request is being executed, the current working directory could have
168changed. Alternatively, you can make sure that you never change the 235changed. Alternatively, you can make sure that you never change the
169current working directory. 236current working directory anywhere in the program and then use relative
237paths.
170 238
171To encode pathnames to byte form, either make sure you either: a) 239To encode pathnames as octets, either make sure you either: a) always pass
172always pass in filenames you got from outside (command line, readdir 240in filenames you got from outside (command line, readdir etc.) without
173etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode 241tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174your pathnames to the locale (or other) encoding in effect in the user 242your pathnames to the locale (or other) encoding in effect in the user
175environment, d) use Glib::filename_from_unicode on unicode filenames or e) 243environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176use something else. 244use something else to ensure your scalar has the correct contents.
245
246This works, btw. independent of the internal UTF-8 bit, which IO::AIO
247handles correctly wether it is set or not.
177 248
178=over 4 249=over 4
179 250
180=item aioreq_pri $pri 251=item $prev_pri = aioreq_pri [$pri]
181 252
182Sets the priority for the next aio request. The default priority 253Returns the priority value that would be used for the next request and, if
254C<$pri> is given, sets the priority for the next aio request.
255
183is C<0>, the minimum and maximum priorities are C<-4> and C<4>, 256The default priority is C<0>, the minimum and maximum priorities are C<-4>
184respectively. Requests with higher priority will be serviced first. 257and C<4>, respectively. Requests with higher priority will be serviced
258first.
185 259
186The priority will be reset to C<0> after each call to one of the C<aio_> 260The priority will be reset to C<0> after each call to one of the C<aio_*>
187functions. 261functions.
188 262
189Example: open a file with low priority, then read something from it with 263Example: open a file with low priority, then read something from it with
190higher priority so the read request is serviced before other low priority 264higher priority so the read request is serviced before other low priority
191open requests (potentially spamming the cache): 265open requests (potentially spamming the cache):
… …
198 aio_read $_[0], ..., sub { 272 aio_read $_[0], ..., sub {
199 ... 273 ...
200 }; 274 };
201 }; 275 };
202 276
277
203=item aioreq_nice $pri_adjust 278=item aioreq_nice $pri_adjust
204 279
205Similar to C<aioreq_pri>, but subtracts the given value from the current 280Similar to C<aioreq_pri>, but subtracts the given value from the current
206priority, so effects are cumulative. 281priority, so the effect is cumulative.
282
207 283
208=item aio_open $pathname, $flags, $mode, $callback->($fh) 284=item aio_open $pathname, $flags, $mode, $callback->($fh)
209 285
210Asynchronously open or create a file and call the callback with a newly 286Asynchronously open or create a file and call the callback with a newly
211created filehandle for the file. 287created filehandle for the file.
… …
217list. They are the same as used by C<sysopen>. 293list. They are the same as used by C<sysopen>.
218 294
219Likewise, C<$mode> specifies the mode of the newly created file, if it 295Likewise, C<$mode> specifies the mode of the newly created file, if it
220didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 296didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
221except that it is mandatory (i.e. use C<0> if you don't create new files, 297except that it is mandatory (i.e. use C<0> if you don't create new files,
222and C<0666> or C<0777> if you do). 298and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
299by the umask in effect then the request is being executed, so better never
300change the umask.
223 301
224Example: 302Example:
225 303
226 aio_open "/etc/passwd", O_RDONLY, 0, sub { 304 aio_open "/etc/passwd", O_RDONLY, 0, sub {
227 if ($_[0]) { 305 if ($_[0]) {
… …
230 } else { 308 } else {
231 die "open failed: $!\n"; 309 die "open failed: $!\n";
232 } 310 }
233 }; 311 };
234 312
313
235=item aio_close $fh, $callback->($status) 314=item aio_close $fh, $callback->($status)
236 315
237Asynchronously close a file and call the callback with the result 316Asynchronously close a file and call the callback with the result
238code. I<WARNING:> although accepted, you should not pass in a perl 317code. I<WARNING:> although accepted, you should not pass in a perl
239filehandle here, as perl will likely close the file descriptor another 318filehandle here, as perl will likely close the file descriptor another
… …
241C<close> or just let filehandles go out of scope. 320C<close> or just let filehandles go out of scope.
242 321
243This is supposed to be a bug in the API, so that might change. It's 322This is supposed to be a bug in the API, so that might change. It's
244therefore best to avoid this function. 323therefore best to avoid this function.
245 324
325
246=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 326=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
247 327
248=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 328=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
249 329
250Reads or writes C<length> bytes from the specified C<fh> and C<offset> 330Reads or writes C<length> bytes from the specified C<fh> and C<offset>
… …
262 aio_read $fh, 7, 15, $buffer, 0, sub { 342 aio_read $fh, 7, 15, $buffer, 0, sub {
263 $_[0] > 0 or die "read error: $!"; 343 $_[0] > 0 or die "read error: $!";
264 print "read $_[0] bytes: <$buffer>\n"; 344 print "read $_[0] bytes: <$buffer>\n";
265 }; 345 };
266 346
267=item aio_move $srcpath, $dstpath, $callback->($status)
268
269Try to move the I<file> (directories not supported as either source or
270destination) from C<$srcpath> to C<$dstpath> and call the callback with
271the C<0> (error) or C<-1> ok.
272
273This is a composite request that tries to rename(2) the file first. If
274rename files with C<EXDEV>, it creates the destination file with mode 0200
275and copies the contents of the source file into it using C<aio_sendfile>,
276followed by restoring atime, mtime, access mode and uid/gid, in that
277order, and unlinking the C<$srcpath>.
278
279If an error occurs, the partial destination file will be unlinked, if
280possible, except when setting atime, mtime, access mode and uid/gid, where
281errors are being ignored.
282
283=cut
284
285sub aio_move($$$) {
286 my ($src, $dst, $cb) = @_;
287
288 my $grp = aio_group $cb;
289
290 add $grp aio_rename $src, $dst, sub {
291 if ($_[0] && $! == EXDEV) {
292 add $grp aio_open $src, O_RDONLY, 0, sub {
293 if (my $src_fh = $_[0]) {
294 my @stat = stat $src_fh;
295
296 add $grp aio_open $dst, O_WRONLY, 0200, sub {
297 if (my $dst_fh = $_[0]) {
298 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
299 close $src_fh;
300
301 if ($_[0] == $stat[7]) {
302 utime $stat[8], $stat[9], $dst;
303 chmod $stat[2] & 07777, $dst_fh;
304 chown $stat[4], $stat[5], $dst_fh;
305 close $dst_fh;
306
307 add $grp aio_unlink $src, sub {
308 $grp->result ($_[0]);
309 };
310 } else {
311 my $errno = $!;
312 add $grp aio_unlink $dst, sub {
313 $! = $errno;
314 $grp->result (-1);
315 };
316 }
317 };
318 } else {
319 $grp->result (-1);
320 }
321 },
322
323 } else {
324 $grp->result (-1);
325 }
326 };
327 } else {
328 $grp->result ($_[0]);
329 }
330 };
331
332 $grp
333}
334 347
335=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 348=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
336 349
337Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 350Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
338reading at byte offset C<$in_offset>, and starts writing at the current 351reading at byte offset C<$in_offset>, and starts writing at the current
… …
352C<$in_fh> than are written, and there is no way to find out how many 365C<$in_fh> than are written, and there is no way to find out how many
353bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 366bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
354provides the number of bytes written to C<$out_fh>. Only if the result 367provides the number of bytes written to C<$out_fh>. Only if the result
355value equals C<$length> one can assume that C<$length> bytes have been 368value equals C<$length> one can assume that C<$length> bytes have been
356read. 369read.
370
357 371
358=item aio_readahead $fh,$offset,$length, $callback->($retval) 372=item aio_readahead $fh,$offset,$length, $callback->($retval)
359 373
360C<aio_readahead> populates the page cache with data from a file so that 374C<aio_readahead> populates the page cache with data from a file so that
361subsequent reads from that file will not block on disk I/O. The C<$offset> 375subsequent reads from that file will not block on disk I/O. The C<$offset>
… …
367file. The current file offset of the file is left unchanged. 381file. The current file offset of the file is left unchanged.
368 382
369If that syscall doesn't exist (likely if your OS isn't Linux) it will be 383If that syscall doesn't exist (likely if your OS isn't Linux) it will be
370emulated by simply reading the data, which would have a similar effect. 384emulated by simply reading the data, which would have a similar effect.
371 385
386
372=item aio_stat $fh_or_path, $callback->($status) 387=item aio_stat $fh_or_path, $callback->($status)
373 388
374=item aio_lstat $fh, $callback->($status) 389=item aio_lstat $fh, $callback->($status)
375 390
376Works like perl's C<stat> or C<lstat> in void context. The callback will 391Works like perl's C<stat> or C<lstat> in void context. The callback will
… …
389 aio_stat "/etc/passwd", sub { 404 aio_stat "/etc/passwd", sub {
390 $_[0] and die "stat failed: $!"; 405 $_[0] and die "stat failed: $!";
391 print "size is ", -s _, "\n"; 406 print "size is ", -s _, "\n";
392 }; 407 };
393 408
409
410=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
411
412Works like perl's C<utime> function (including the special case of $atime
413and $mtime being undef). Fractional times are supported if the underlying
414syscalls support them.
415
416When called with a pathname, uses utimes(2) if available, otherwise
417utime(2). If called on a file descriptor, uses futimes(2) if available,
418otherwise returns ENOSYS, so this is not portable.
419
420Examples:
421
422 # set atime and mtime to current time (basically touch(1)):
423 aio_utime "path", undef, undef;
424 # set atime to current time and mtime to beginning of the epoch:
425 aio_utime "path", time, undef; # undef==0
426
427
428=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
429
430Works like perl's C<chown> function, except that C<undef> for either $uid
431or $gid is being interpreted as "do not change" (but -1 can also be used).
432
433Examples:
434
435 # same as "chown root path" in the shell:
436 aio_chown "path", 0, -1;
437 # same as above:
438 aio_chown "path", 0, undef;
439
440
441=item aio_chmod $fh_or_path, $mode, $callback->($status)
442
443Works like perl's C<chmod> function.
444
445
394=item aio_unlink $pathname, $callback->($status) 446=item aio_unlink $pathname, $callback->($status)
395 447
396Asynchronously unlink (delete) a file and call the callback with the 448Asynchronously unlink (delete) a file and call the callback with the
397result code. 449result code.
398 450
451
452=item aio_mknod $path, $mode, $dev, $callback->($status)
453
454[EXPERIMENTAL]
455
456Asynchronously create a device node (or fifo). See mknod(2).
457
458The only (POSIX-) portable way of calling this function is:
459
460 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
461
462
399=item aio_link $srcpath, $dstpath, $callback->($status) 463=item aio_link $srcpath, $dstpath, $callback->($status)
400 464
401Asynchronously create a new link to the existing object at C<$srcpath> at 465Asynchronously create a new link to the existing object at C<$srcpath> at
402the path C<$dstpath> and call the callback with the result code. 466the path C<$dstpath> and call the callback with the result code.
403 467
468
404=item aio_symlink $srcpath, $dstpath, $callback->($status) 469=item aio_symlink $srcpath, $dstpath, $callback->($status)
405 470
406Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 471Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
407the path C<$dstpath> and call the callback with the result code. 472the path C<$dstpath> and call the callback with the result code.
408 473
474
475=item aio_readlink $path, $callback->($link)
476
477Asynchronously read the symlink specified by C<$path> and pass it to
478the callback. If an error occurs, nothing or undef gets passed to the
479callback.
480
481
409=item aio_rename $srcpath, $dstpath, $callback->($status) 482=item aio_rename $srcpath, $dstpath, $callback->($status)
410 483
411Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 484Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
412rename(2) and call the callback with the result code. 485rename(2) and call the callback with the result code.
413 486
487
488=item aio_mkdir $pathname, $mode, $callback->($status)
489
490Asynchronously mkdir (create) a directory and call the callback with
491the result code. C<$mode> will be modified by the umask at the time the
492request is executed, so do not change your umask.
493
494
414=item aio_rmdir $pathname, $callback->($status) 495=item aio_rmdir $pathname, $callback->($status)
415 496
416Asynchronously rmdir (delete) a directory and call the callback with the 497Asynchronously rmdir (delete) a directory and call the callback with the
417result code. 498result code.
499
418 500
419=item aio_readdir $pathname, $callback->($entries) 501=item aio_readdir $pathname, $callback->($entries)
420 502
421Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 503Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
422directory (i.e. opendir + readdir + closedir). The entries will not be 504directory (i.e. opendir + readdir + closedir). The entries will not be
423sorted, and will B<NOT> include the C<.> and C<..> entries. 505sorted, and will B<NOT> include the C<.> and C<..> entries.
424 506
425The callback a single argument which is either C<undef> or an array-ref 507The callback a single argument which is either C<undef> or an array-ref
426with the filenames. 508with the filenames.
509
510
511=item aio_load $path, $data, $callback->($status)
512
513This is a composite request that tries to fully load the given file into
514memory. Status is the same as with aio_read.
515
516=cut
517
518sub aio_load($$;$) {
519 aio_block {
520 my ($path, undef, $cb) = @_;
521 my $data = \$_[1];
522
523 my $pri = aioreq_pri;
524 my $grp = aio_group $cb;
525
526 aioreq_pri $pri;
527 add $grp aio_open $path, O_RDONLY, 0, sub {
528 my $fh = shift
529 or return $grp->result (-1);
530
531 aioreq_pri $pri;
532 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
533 $grp->result ($_[0]);
534 };
535 };
536
537 $grp
538 }
539}
540
541=item aio_copy $srcpath, $dstpath, $callback->($status)
542
543Try to copy the I<file> (directories not supported as either source or
544destination) from C<$srcpath> to C<$dstpath> and call the callback with
545the C<0> (error) or C<-1> ok.
546
547This is a composite request that it creates the destination file with
548mode 0200 and copies the contents of the source file into it using
549C<aio_sendfile>, followed by restoring atime, mtime, access mode and
550uid/gid, in that order.
551
552If an error occurs, the partial destination file will be unlinked, if
553possible, except when setting atime, mtime, access mode and uid/gid, where
554errors are being ignored.
555
556=cut
557
558sub aio_copy($$;$) {
559 aio_block {
560 my ($src, $dst, $cb) = @_;
561
562 my $pri = aioreq_pri;
563 my $grp = aio_group $cb;
564
565 aioreq_pri $pri;
566 add $grp aio_open $src, O_RDONLY, 0, sub {
567 if (my $src_fh = $_[0]) {
568 my @stat = stat $src_fh;
569
570 aioreq_pri $pri;
571 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
572 if (my $dst_fh = $_[0]) {
573 aioreq_pri $pri;
574 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
575 if ($_[0] == $stat[7]) {
576 $grp->result (0);
577 close $src_fh;
578
579 # those should not normally block. should. should.
580 utime $stat[8], $stat[9], $dst;
581 chmod $stat[2] & 07777, $dst_fh;
582 chown $stat[4], $stat[5], $dst_fh;
583 close $dst_fh;
584 } else {
585 $grp->result (-1);
586 close $src_fh;
587 close $dst_fh;
588
589 aioreq $pri;
590 add $grp aio_unlink $dst;
591 }
592 };
593 } else {
594 $grp->result (-1);
595 }
596 },
597
598 } else {
599 $grp->result (-1);
600 }
601 };
602
603 $grp
604 }
605}
606
607=item aio_move $srcpath, $dstpath, $callback->($status)
608
609Try to move the I<file> (directories not supported as either source or
610destination) from C<$srcpath> to C<$dstpath> and call the callback with
611the C<0> (error) or C<-1> ok.
612
613This is a composite request that tries to rename(2) the file first. If
614rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if
615that is successful, unlinking the C<$srcpath>.
616
617=cut
618
619sub aio_move($$;$) {
620 aio_block {
621 my ($src, $dst, $cb) = @_;
622
623 my $pri = aioreq_pri;
624 my $grp = aio_group $cb;
625
626 aioreq_pri $pri;
627 add $grp aio_rename $src, $dst, sub {
628 if ($_[0] && $! == EXDEV) {
629 aioreq_pri $pri;
630 add $grp aio_copy $src, $dst, sub {
631 $grp->result ($_[0]);
632
633 if (!$_[0]) {
634 aioreq_pri $pri;
635 add $grp aio_unlink $src;
636 }
637 };
638 } else {
639 $grp->result ($_[0]);
640 }
641 };
642
643 $grp
644 }
645}
427 646
428=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 647=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
429 648
430Scans a directory (similar to C<aio_readdir>) but additionally tries to 649Scans a directory (similar to C<aio_readdir>) but additionally tries to
431efficiently separate the entries of directory C<$path> into two sets of 650efficiently separate the entries of directory C<$path> into two sets of
… …
433recurse into (everything else, including symlinks to directories). 652recurse into (everything else, including symlinks to directories).
434 653
435C<aio_scandir> is a composite request that creates of many sub requests_ 654C<aio_scandir> is a composite request that creates of many sub requests_
436C<$maxreq> specifies the maximum number of outstanding aio requests that 655C<$maxreq> specifies the maximum number of outstanding aio requests that
437this function generates. If it is C<< <= 0 >>, then a suitable default 656this function generates. If it is C<< <= 0 >>, then a suitable default
438will be chosen (currently 6). 657will be chosen (currently 4).
439 658
440On error, the callback is called without arguments, otherwise it receives 659On error, the callback is called without arguments, otherwise it receives
441two array-refs with path-relative entry names. 660two array-refs with path-relative entry names.
442 661
443Example: 662Example:
… …
477as those tend to return 0 or 1 as link counts, which disables the 696as those tend to return 0 or 1 as link counts, which disables the
478directory counting heuristic. 697directory counting heuristic.
479 698
480=cut 699=cut
481 700
482sub aio_scandir($$$) { 701sub aio_scandir($$;$) {
702 aio_block {
483 my ($path, $maxreq, $cb) = @_; 703 my ($path, $maxreq, $cb) = @_;
484 704
705 my $pri = aioreq_pri;
706
485 my $grp = aio_group $cb; 707 my $grp = aio_group $cb;
486 708
487 $maxreq = 6 if $maxreq <= 0; 709 $maxreq = 4 if $maxreq <= 0;
488 710
489 # stat once 711 # stat once
712 aioreq_pri $pri;
490 add $grp aio_stat $path, sub { 713 add $grp aio_stat $path, sub {
491 return $grp->result () if $_[0]; 714 return $grp->result () if $_[0];
492 my $now = time; 715 my $now = time;
493 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 716 my $hash1 = join ":", (stat _)[0,1,3,7,9];
494 717
495 # read the directory entries 718 # read the directory entries
719 aioreq_pri $pri;
496 add $grp aio_readdir $path, sub { 720 add $grp aio_readdir $path, sub {
497 my $entries = shift 721 my $entries = shift
498 or return $grp->result (); 722 or return $grp->result ();
499 723
500 # stat the dir another time 724 # stat the dir another time
725 aioreq_pri $pri;
501 add $grp aio_stat $path, sub { 726 add $grp aio_stat $path, sub {
502 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 727 my $hash2 = join ":", (stat _)[0,1,3,7,9];
503 728
504 my $ndirs; 729 my $ndirs;
505 730
506 # take the slow route if anything looks fishy 731 # take the slow route if anything looks fishy
507 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 732 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
508 $ndirs = -1; 733 $ndirs = -1;
509 } else { 734 } else {
510 # if nlink == 2, we are finished 735 # if nlink == 2, we are finished
511 # on non-posix-fs's, we rely on nlink < 2 736 # on non-posix-fs's, we rely on nlink < 2
512 $ndirs = (stat _)[3] - 2 737 $ndirs = (stat _)[3] - 2
513 or return $grp->result ([], $entries); 738 or return $grp->result ([], $entries);
514 } 739 }
515 740
516 # sort into likely dirs and likely nondirs 741 # sort into likely dirs and likely nondirs
517 # dirs == files without ".", short entries first 742 # dirs == files without ".", short entries first
518 $entries = [map $_->[0], 743 $entries = [map $_->[0],
519 sort { $b->[1] cmp $a->[1] } 744 sort { $b->[1] cmp $a->[1] }
520 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length], 745 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
521 @$entries]; 746 @$entries];
522 747
523 my (@dirs, @nondirs); 748 my (@dirs, @nondirs);
524 749
525 my $statgrp = add $grp aio_group sub { 750 my $statgrp = add $grp aio_group sub {
526 $grp->result (\@dirs, \@nondirs); 751 $grp->result (\@dirs, \@nondirs);
527 }; 752 };
528 753
529 limit $statgrp $maxreq; 754 limit $statgrp $maxreq;
530 feed $statgrp sub { 755 feed $statgrp sub {
531 return unless @$entries; 756 return unless @$entries;
532 my $entry = pop @$entries; 757 my $entry = pop @$entries;
533 758
759 aioreq_pri $pri;
534 add $statgrp aio_stat "$path/$entry/.", sub { 760 add $statgrp aio_stat "$path/$entry/.", sub {
535 if ($_[0] < 0) { 761 if ($_[0] < 0) {
536 push @nondirs, $entry; 762 push @nondirs, $entry;
537 } else { 763 } else {
538 # need to check for real directory 764 # need to check for real directory
765 aioreq_pri $pri;
539 add $statgrp aio_lstat "$path/$entry", sub { 766 add $statgrp aio_lstat "$path/$entry", sub {
540 if (-d _) { 767 if (-d _) {
541 push @dirs, $entry; 768 push @dirs, $entry;
542 769
543 unless (--$ndirs) { 770 unless (--$ndirs) {
544 push @nondirs, @$entries; 771 push @nondirs, @$entries;
545 feed $statgrp; 772 feed $statgrp;
773 }
774 } else {
775 push @nondirs, $entry;
546 } 776 }
547 } else {
548 push @nondirs, $entry;
549 } 777 }
550 } 778 }
551 } 779 };
552 }; 780 };
553 }; 781 };
554 }; 782 };
555 }; 783 };
784
785 $grp
556 }; 786 }
787}
557 788
789=item aio_rmtree $path, $callback->($status)
790
791Delete a directory tree starting (and including) C<$path>, return the
792status of the final C<rmdir> only. This is a composite request that
793uses C<aio_scandir> to recurse into and rmdir directories, and unlink
794everything else.
795
796=cut
797
798sub aio_rmtree;
799sub aio_rmtree($;$) {
800 aio_block {
801 my ($path, $cb) = @_;
802
803 my $pri = aioreq_pri;
804 my $grp = aio_group $cb;
805
806 aioreq_pri $pri;
807 add $grp aio_scandir $path, 0, sub {
808 my ($dirs, $nondirs) = @_;
809
810 my $dirgrp = aio_group sub {
811 add $grp aio_rmdir $path, sub {
812 $grp->result ($_[0]);
813 };
814 };
815
816 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
817 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
818
819 add $grp $dirgrp;
820 };
821
558 $grp 822 $grp
823 }
559} 824}
560 825
561=item aio_fsync $fh, $callback->($status) 826=item aio_fsync $fh, $callback->($status)
562 827
563Asynchronously call fsync on the given filehandle and call the callback 828Asynchronously call fsync on the given filehandle and call the callback
… …
714itself. Useful when you queued a lot of events but got a result early. 979itself. Useful when you queued a lot of events but got a result early.
715 980
716=item $grp->result (...) 981=item $grp->result (...)
717 982
718Set the result value(s) that will be passed to the group callback when all 983Set the result value(s) that will be passed to the group callback when all
719subrequests have finished. By default, no argument will be passed. 984subrequests have finished and set thre groups errno to the current value
985of errno (just like calling C<errno> without an error number). By default,
986no argument will be passed and errno is zero.
987
988=item $grp->errno ([$errno])
989
990Sets the group errno value to C<$errno>, or the current value of errno
991when the argument is missing.
992
993Every aio request has an associated errno value that is restored when
994the callback is invoked. This method lets you change this value from its
995default (0).
996
997Calling C<result> will also set errno, so make sure you either set C<$!>
998before the call to C<result>, or call c<errno> after it.
720 999
721=item feed $grp $callback->($grp) 1000=item feed $grp $callback->($grp)
722 1001
723Sets a feeder/generator on this group: every group can have an attached 1002Sets a feeder/generator on this group: every group can have an attached
724generator that generates requests if idle. The idea behind this is that, 1003generator that generates requests if idle. The idea behind this is that,
… …
763 1042
764=back 1043=back
765 1044
766=head2 SUPPORT FUNCTIONS 1045=head2 SUPPORT FUNCTIONS
767 1046
1047=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1048
768=over 4 1049=over 4
769 1050
770=item $fileno = IO::AIO::poll_fileno 1051=item $fileno = IO::AIO::poll_fileno
771 1052
772Return the I<request result pipe file descriptor>. This filehandle must be 1053Return the I<request result pipe file descriptor>. This filehandle must be
… …
776 1057
777See C<poll_cb> for an example. 1058See C<poll_cb> for an example.
778 1059
779=item IO::AIO::poll_cb 1060=item IO::AIO::poll_cb
780 1061
781Process all outstanding events on the result pipe. You have to call this 1062Process some outstanding events on the result pipe. You have to call this
782regularly. Returns the number of events processed. Returns immediately 1063regularly. Returns the number of events processed. Returns immediately
783when no events are outstanding. 1064when no events are outstanding. The amount of events processed depends on
1065the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1066
1067If not all requests were processed for whatever reason, the filehandle
1068will still be ready when C<poll_cb> returns.
784 1069
785Example: Install an Event watcher that automatically calls 1070Example: Install an Event watcher that automatically calls
786IO::AIO::poll_cb with high priority: 1071IO::AIO::poll_cb with high priority:
787 1072
788 Event->io (fd => IO::AIO::poll_fileno, 1073 Event->io (fd => IO::AIO::poll_fileno,
789 poll => 'r', async => 1, 1074 poll => 'r', async => 1,
790 cb => \&IO::AIO::poll_cb); 1075 cb => \&IO::AIO::poll_cb);
791 1076
1077=item IO::AIO::max_poll_reqs $nreqs
1078
1079=item IO::AIO::max_poll_time $seconds
1080
1081These set the maximum number of requests (default C<0>, meaning infinity)
1082that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1083the maximum amount of time (default C<0>, meaning infinity) spent in
1084C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1085of time C<poll_cb> is allowed to use).
1086
1087Setting C<max_poll_time> to a non-zero value creates an overhead of one
1088syscall per request processed, which is not normally a problem unless your
1089callbacks are really really fast or your OS is really really slow (I am
1090not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1091
1092Setting these is useful if you want to ensure some level of
1093interactiveness when perl is not fast enough to process all requests in
1094time.
1095
1096For interactive programs, values such as C<0.01> to C<0.1> should be fine.
1097
1098Example: Install an Event watcher that automatically calls
1099IO::AIO::poll_cb with low priority, to ensure that other parts of the
1100program get the CPU sometimes even under high AIO load.
1101
1102 # try not to spend much more than 0.1s in poll_cb
1103 IO::AIO::max_poll_time 0.1;
1104
1105 # use a low priority so other tasks have priority
1106 Event->io (fd => IO::AIO::poll_fileno,
1107 poll => 'r', nice => 1,
1108 cb => &IO::AIO::poll_cb);
1109
792=item IO::AIO::poll_wait 1110=item IO::AIO::poll_wait
793 1111
1112If there are any outstanding requests and none of them in the result
794Wait till the result filehandle becomes ready for reading (simply does a 1113phase, wait till the result filehandle becomes ready for reading (simply
795C<select> on the filehandle. This is useful if you want to synchronously wait 1114does a C<select> on the filehandle. This is useful if you want to
796for some requests to finish). 1115synchronously wait for some requests to finish).
797 1116
798See C<nreqs> for an example. 1117See C<nreqs> for an example.
799 1118
1119=item IO::AIO::poll
1120
1121Waits until some requests have been handled.
1122
1123Returns the number of requests processed, but is otherwise strictly
1124equivalent to:
1125
1126 IO::AIO::poll_wait, IO::AIO::poll_cb
1127
800=item IO::AIO::nreqs 1128=item IO::AIO::flush
801 1129
802Returns the number of requests currently outstanding (i.e. for which their 1130Wait till all outstanding AIO requests have been handled.
803callback has not been invoked yet).
804 1131
805Example: wait till there are no outstanding requests anymore: 1132Strictly equivalent to:
806 1133
807 IO::AIO::poll_wait, IO::AIO::poll_cb 1134 IO::AIO::poll_wait, IO::AIO::poll_cb
808 while IO::AIO::nreqs; 1135 while IO::AIO::nreqs;
809 1136
810=item IO::AIO::flush 1137=back
811 1138
812Wait till all outstanding AIO requests have been handled. 1139=head3 CONTROLLING THE NUMBER OF THREADS
813 1140
814Strictly equivalent to: 1141=over
815
816 IO::AIO::poll_wait, IO::AIO::poll_cb
817 while IO::AIO::nreqs;
818
819=item IO::AIO::poll
820
821Waits until some requests have been handled.
822
823Strictly equivalent to:
824
825 IO::AIO::poll_wait, IO::AIO::poll_cb
826 if IO::AIO::nreqs;
827 1142
828=item IO::AIO::min_parallel $nthreads 1143=item IO::AIO::min_parallel $nthreads
829 1144
830Set the minimum number of AIO threads to C<$nthreads>. The current 1145Set the minimum number of AIO threads to C<$nthreads>. The current
831default is C<8>, which means eight asynchronous operations can execute 1146default is C<8>, which means eight asynchronous operations can execute
832concurrently at any one time (the number of outstanding requests, 1147concurrently at any one time (the number of outstanding requests,
833however, is unlimited). 1148however, is unlimited).
834 1149
835IO::AIO starts threads only on demand, when an AIO request is queued and 1150IO::AIO starts threads only on demand, when an AIO request is queued and
836no free thread exists. 1151no free thread exists. Please note that queueing up a hundred requests can
1152create demand for a hundred threads, even if it turns out that everything
1153is in the cache and could have been processed faster by a single thread.
837 1154
838It is recommended to keep the number of threads relatively low, as some 1155It is recommended to keep the number of threads relatively low, as some
839Linux kernel versions will scale negatively with the number of threads 1156Linux kernel versions will scale negatively with the number of threads
840(higher parallelity => MUCH higher latency). With current Linux 2.6 1157(higher parallelity => MUCH higher latency). With current Linux 2.6
841versions, 4-32 threads should be fine. 1158versions, 4-32 threads should be fine.
… …
855This module automatically runs C<max_parallel 0> at program end, to ensure 1172This module automatically runs C<max_parallel 0> at program end, to ensure
856that all threads are killed and that there are no outstanding requests. 1173that all threads are killed and that there are no outstanding requests.
857 1174
858Under normal circumstances you don't need to call this function. 1175Under normal circumstances you don't need to call this function.
859 1176
1177=item IO::AIO::max_idle $nthreads
1178
1179Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1180threads that did not get a request to process within 10 seconds). That
1181means if a thread becomes idle while C<$nthreads> other threads are also
1182idle, it will free its resources and exit.
1183
1184This is useful when you allow a large number of threads (e.g. 100 or 1000)
1185to allow for extremely high load situations, but want to free resources
1186under normal circumstances (1000 threads can easily consume 30MB of RAM).
1187
1188The default is probably ok in most situations, especially if thread
1189creation is fast. If thread creation is very slow on your system you might
1190want to use larger values.
1191
860=item $oldnreqs = IO::AIO::max_outstanding $nreqs 1192=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
861 1193
862[REMOVED] 1194This is a very bad function to use in interactive programs because it
1195blocks, and a bad way to reduce concurrency because it is inexact: Better
1196use an C<aio_group> together with a feed callback.
863 1197
864Pre-2.x versions used max_outstanding for a crude request queue length limit.
865
866In 2.x+ you are advised to use a group and a feeder to limit
867concurrency. The max_outstanding feature ran very unstable (endless
868recursions causing segfaults, bad interaction with groups etc.) and was
869removed.
870
871I am deeply sorry, but I am still on the hunt for a good limiting interface.
872
873Original description was as follows:
874
875Sets the maximum number of outstanding requests to C<$nreqs>. If you try 1198Sets the maximum number of outstanding requests to C<$nreqs>. If you
876to queue up more than this number of requests, the caller will block until 1199to queue up more than this number of requests, the next call to the
877some requests have been handled. 1200C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1201function will block until the limit is no longer exceeded.
1202
1203The default value is very large, so there is no practical limit on the
1204number of outstanding requests.
1205
1206You can still queue as many requests as you want. Therefore,
1207C<max_oustsanding> is mainly useful in simple scripts (with low values) or
1208as a stop gap to shield against fatal memory overflow (with large values).
1209
1210=back
1211
1212=head3 STATISTICAL INFORMATION
1213
1214=over
1215
1216=item IO::AIO::nreqs
1217
1218Returns the number of requests currently in the ready, execute or pending
1219states (i.e. for which their callback has not been invoked yet).
1220
1221Example: wait till there are no outstanding requests anymore:
1222
1223 IO::AIO::poll_wait, IO::AIO::poll_cb
1224 while IO::AIO::nreqs;
1225
1226=item IO::AIO::nready
1227
1228Returns the number of requests currently in the ready state (not yet
1229executed).
1230
1231=item IO::AIO::npending
1232
1233Returns the number of requests currently in the pending state (executed,
1234but not yet processed by poll_cb).
878 1235
879=back 1236=back
880 1237
881=cut 1238=cut
882 1239
… …
896 *$sym 1253 *$sym
897} 1254}
898 1255
899min_parallel 8; 1256min_parallel 8;
900 1257
901END { 1258END { flush }
902 max_parallel 0;
903}
904 1259
9051; 12601;
906 1261
907=head2 FORK BEHAVIOUR 1262=head2 FORK BEHAVIOUR
908 1263

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