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Revision 1.209 by root, Tue Sep 27 00:41:51 2011 UTC vs.
Revision 1.280 by root, Mon Feb 19 13:37:13 2018 UTC

1=head1 NAME 1=head1 NAME
2 2
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous/Advanced Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
58not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
59files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
60aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
61using threads anyway. 61using threads anyway.
62 62
63In addition to asynchronous I/O, this module also exports some rather
64arcane interfaces, such as C<madvise> or linux's C<splice> system call,
65which is why the C<A> in C<AIO> can also mean I<advanced>.
66
63Although the module will work in the presence of other (Perl-) threads, 67Although the module will work in the presence of other (Perl-) threads,
64it is currently not reentrant in any way, so use appropriate locking 68it is currently not reentrant in any way, so use appropriate locking
65yourself, always call C<poll_cb> from within the same thread, or never 69yourself, always call C<poll_cb> from within the same thread, or never
66call C<poll_cb> (or other C<aio_> functions) recursively. 70call C<poll_cb> (or other C<aio_> functions) recursively.
67 71
68=head2 EXAMPLE 72=head2 EXAMPLE
69 73
70This is a simple example that uses the EV module and loads 74This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 75F</etc/passwd> asynchronously:
72 76
73 use Fcntl;
74 use EV; 77 use EV;
75 use IO::AIO; 78 use IO::AIO;
76 79
77 # register the IO::AIO callback with EV 80 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 81 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
95 98
96 # file contents now in $contents 99 # file contents now in $contents
97 print $contents; 100 print $contents;
98 101
99 # exit event loop and program 102 # exit event loop and program
100 EV::unloop; 103 EV::break;
101 }; 104 };
102 }; 105 };
103 106
104 # possibly queue up other requests, or open GUI windows, 107 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 108 # check for sockets etc. etc.
106 109
107 # process events as long as there are some: 110 # process events as long as there are some:
108 EV::loop; 111 EV::run;
109 112
110=head1 REQUEST ANATOMY AND LIFETIME 113=head1 REQUEST ANATOMY AND LIFETIME
111 114
112Every C<aio_*> function creates a request. which is a C data structure not 115Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 116directly visible to Perl.
168use common::sense; 171use common::sense;
169 172
170use base 'Exporter'; 173use base 'Exporter';
171 174
172BEGIN { 175BEGIN {
173 our $VERSION = '4.0'; 176 our $VERSION = 4.4;
174 177
175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 178 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 179 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
180 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 184 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 187 aio_statvfs
188 aio_slurp
185 aio_wd); 189 aio_wd);
186 190
187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 191 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 192 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
189 min_parallel max_parallel max_idle idle_timeout 193 min_parallel max_parallel max_idle idle_timeout
202 206
203=head1 FUNCTIONS 207=head1 FUNCTIONS
204 208
205=head2 QUICK OVERVIEW 209=head2 QUICK OVERVIEW
206 210
207This section simply lists the prototypes of the most important functions 211This section simply lists the prototypes most of the functions for
208for quick reference. See the following sections for function-by-function 212quick reference. See the following sections for function-by-function
209documentation. 213documentation.
210 214
211 aio_wd $pathname, $callback->($wd) 215 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh) 216 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status) 217 aio_close $fh, $callback->($status)
218 aio_seek $fh,$offset,$whence, $callback->($offs)
214 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 219 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
215 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 220 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 221 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
217 aio_readahead $fh,$offset,$length, $callback->($retval) 222 aio_readahead $fh,$offset,$length, $callback->($retval)
218 aio_stat $fh_or_path, $callback->($status) 223 aio_stat $fh_or_path, $callback->($status)
219 aio_lstat $fh, $callback->($status) 224 aio_lstat $fh, $callback->($status)
220 aio_statvfs $fh_or_path, $callback->($statvfs) 225 aio_statvfs $fh_or_path, $callback->($statvfs)
221 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 226 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
222 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 227 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
228 aio_chmod $fh_or_path, $mode, $callback->($status)
223 aio_truncate $fh_or_path, $offset, $callback->($status) 229 aio_truncate $fh_or_path, $offset, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status) 230 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
231 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
225 aio_unlink $pathname, $callback->($status) 232 aio_unlink $pathname, $callback->($status)
226 aio_mknod $pathname, $mode, $dev, $callback->($status) 233 aio_mknod $pathname, $mode, $dev, $callback->($status)
227 aio_link $srcpath, $dstpath, $callback->($status) 234 aio_link $srcpath, $dstpath, $callback->($status)
228 aio_symlink $srcpath, $dstpath, $callback->($status) 235 aio_symlink $srcpath, $dstpath, $callback->($status)
229 aio_readlink $pathname, $callback->($link) 236 aio_readlink $pathname, $callback->($link)
230 aio_realpath $pathname, $callback->($link) 237 aio_realpath $pathname, $callback->($path)
231 aio_rename $srcpath, $dstpath, $callback->($status) 238 aio_rename $srcpath, $dstpath, $callback->($status)
239 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
232 aio_mkdir $pathname, $mode, $callback->($status) 240 aio_mkdir $pathname, $mode, $callback->($status)
233 aio_rmdir $pathname, $callback->($status) 241 aio_rmdir $pathname, $callback->($status)
234 aio_readdir $pathname, $callback->($entries) 242 aio_readdir $pathname, $callback->($entries)
235 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 243 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
236 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 244 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
237 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 245 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
246 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
238 aio_load $pathname, $data, $callback->($status) 247 aio_load $pathname, $data, $callback->($status)
239 aio_copy $srcpath, $dstpath, $callback->($status) 248 aio_copy $srcpath, $dstpath, $callback->($status)
240 aio_move $srcpath, $dstpath, $callback->($status) 249 aio_move $srcpath, $dstpath, $callback->($status)
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_rmtree $pathname, $callback->($status) 250 aio_rmtree $pathname, $callback->($status)
251 aio_fcntl $fh, $cmd, $arg, $callback->($status)
252 aio_ioctl $fh, $request, $buf, $callback->($status)
243 aio_sync $callback->($status) 253 aio_sync $callback->($status)
244 aio_syncfs $fh, $callback->($status) 254 aio_syncfs $fh, $callback->($status)
245 aio_fsync $fh, $callback->($status) 255 aio_fsync $fh, $callback->($status)
246 aio_fdatasync $fh, $callback->($status) 256 aio_fdatasync $fh, $callback->($status)
247 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 257 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
248 aio_pathsync $pathname, $callback->($status) 258 aio_pathsync $pathname, $callback->($status)
249 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
250 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 260 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 261 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
252 aio_mlockall $flags, $callback->($status) 262 aio_mlockall $flags, $callback->($status)
253 aio_group $callback->(...) 263 aio_group $callback->(...)
254 aio_nop $callback->() 264 aio_nop $callback->()
268 IO::AIO::idle_timeout $seconds 278 IO::AIO::idle_timeout $seconds
269 IO::AIO::max_outstanding $maxreqs 279 IO::AIO::max_outstanding $maxreqs
270 IO::AIO::nreqs 280 IO::AIO::nreqs
271 IO::AIO::nready 281 IO::AIO::nready
272 IO::AIO::npending 282 IO::AIO::npending
283 $nfd = IO::AIO::get_fdlimit [EXPERIMENTAL]
284 IO::AIO::min_fdlimit $nfd [EXPERIMENTAL]
273 285
274 IO::AIO::sendfile $ofh, $ifh, $offset, $count 286 IO::AIO::sendfile $ofh, $ifh, $offset, $count
275 IO::AIO::fadvise $fh, $offset, $len, $advice 287 IO::AIO::fadvise $fh, $offset, $len, $advice
288 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
289 IO::AIO::munmap $scalar
276 IO::AIO::madvise $scalar, $offset, $length, $advice 290 IO::AIO::madvise $scalar, $offset, $length, $advice
277 IO::AIO::mprotect $scalar, $offset, $length, $protect 291 IO::AIO::mprotect $scalar, $offset, $length, $protect
278 IO::AIO::munlock $scalar, $offset = 0, $length = undef 292 IO::AIO::munlock $scalar, $offset = 0, $length = undef
279 IO::AIO::munlockall 293 IO::AIO::munlockall
280 294
281=head2 AIO REQUEST FUNCTIONS 295=head2 API NOTES
282 296
283All the C<aio_*> calls are more or less thin wrappers around the syscall 297All the C<aio_*> calls are more or less thin wrappers around the syscall
284with the same name (sans C<aio_>). The arguments are similar or identical, 298with the same name (sans C<aio_>). The arguments are similar or identical,
285and they all accept an additional (and optional) C<$callback> argument 299and they all accept an additional (and optional) C<$callback> argument
286which must be a code reference. This code reference will get called with 300which must be a code reference. This code reference will be called after
287the syscall return code (e.g. most syscalls return C<-1> on error, unlike 301the syscall has been executed in an asynchronous fashion. The results
288perl, which usually delivers "false") as its sole argument after the given 302of the request will be passed as arguments to the callback (and, if an
289syscall has been executed asynchronously. 303error occured, in C<$!>) - for most requests the syscall return code (e.g.
304most syscalls return C<-1> on error, unlike perl, which usually delivers
305"false").
306
307Some requests (such as C<aio_readdir>) pass the actual results and
308communicate failures by passing C<undef>.
290 309
291All functions expecting a filehandle keep a copy of the filehandle 310All functions expecting a filehandle keep a copy of the filehandle
292internally until the request has finished. 311internally until the request has finished.
293 312
294All functions return request objects of type L<IO::AIO::REQ> that allow 313All functions return request objects of type L<IO::AIO::REQ> that allow
295further manipulation of those requests while they are in-flight. 314further manipulation of those requests while they are in-flight.
296 315
297The pathnames you pass to these routines I<should> be absolute. The 316The pathnames you pass to these routines I<should> be absolute. The
298reason for this is that at the time the request is being executed, the 317reason for this is that at the time the request is being executed, the
299current working directory could have changed. Alternatively, you can make 318current working directory could have changed. Alternatively, you can
300sure that you never change the current working directory anywhere in 319make sure that you never change the current working directory anywhere
301the program and then use relative paths. Lastly, you can take advantage 320in the program and then use relative paths. You can also take advantage
302of IO::AIOs working directory abstraction - see the description of the 321of IO::AIOs working directory abstraction, that lets you specify paths
322relative to some previously-opened "working directory object" - see the
303C<IO::AIO::WD> class later in this document. 323description of the C<IO::AIO::WD> class later in this document.
304 324
305To encode pathnames as octets, either make sure you either: a) always pass 325To encode pathnames as octets, either make sure you either: a) always pass
306in filenames you got from outside (command line, readdir etc.) without 326in filenames you got from outside (command line, readdir etc.) without
307tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 327tinkering, b) are in your native filesystem encoding, c) use the Encode
308your pathnames to the locale (or other) encoding in effect in the user 328module and encode your pathnames to the locale (or other) encoding in
309environment, d) use Glib::filename_from_unicode on unicode filenames or e) 329effect in the user environment, d) use Glib::filename_from_unicode on
310use something else to ensure your scalar has the correct contents. 330unicode filenames or e) use something else to ensure your scalar has the
331correct contents.
311 332
312This works, btw. independent of the internal UTF-8 bit, which IO::AIO 333This works, btw. independent of the internal UTF-8 bit, which IO::AIO
313handles correctly whether it is set or not. 334handles correctly whether it is set or not.
335
336=head2 AIO REQUEST FUNCTIONS
314 337
315=over 4 338=over 4
316 339
317=item $prev_pri = aioreq_pri [$pri] 340=item $prev_pri = aioreq_pri [$pri]
318 341
348 371
349 372
350=item aio_open $pathname, $flags, $mode, $callback->($fh) 373=item aio_open $pathname, $flags, $mode, $callback->($fh)
351 374
352Asynchronously open or create a file and call the callback with a newly 375Asynchronously open or create a file and call the callback with a newly
353created filehandle for the file. 376created filehandle for the file (or C<undef> in case of an error).
354 377
355The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 378The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
356for an explanation. 379for an explanation.
357 380
358The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 381The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
381following POSIX and non-POSIX constants are available (missing ones on 404following POSIX and non-POSIX constants are available (missing ones on
382your system are, as usual, C<0>): 405your system are, as usual, C<0>):
383 406
384C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 407C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
385C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>, 408C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
386C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>. 409C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
387 410
388 411
389=item aio_close $fh, $callback->($status) 412=item aio_close $fh, $callback->($status)
390 413
391Asynchronously close a file and call the callback with the result 414Asynchronously close a file and call the callback with the result
401Or in other words: the file descriptor will be closed, but it will not be 424Or in other words: the file descriptor will be closed, but it will not be
402free for reuse until the perl filehandle is closed. 425free for reuse until the perl filehandle is closed.
403 426
404=cut 427=cut
405 428
429=item aio_seek $fh, $offset, $whence, $callback->($offs)
430
431Seeks the filehandle to the new C<$offset>, similarly to perl's
432C<sysseek>. The C<$whence> can use the traditional values (C<0> for
433C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
434C<IO::AIO::SEEK_END>).
435
436The resulting absolute offset will be passed to the callback, or C<-1> in
437case of an error.
438
439In theory, the C<$whence> constants could be different than the
440corresponding values from L<Fcntl>, but perl guarantees they are the same,
441so don't panic.
442
443As a GNU/Linux (and maybe Solaris) extension, also the constants
444C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
445could be found. No guarantees about suitability for use in C<aio_seek> or
446Perl's C<sysseek> can be made though, although I would naively assume they
447"just work".
448
406=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 449=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
407 450
408=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 451=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
409 452
410Reads or writes C<$length> bytes from or to the specified C<$fh> and 453Reads or writes C<$length> bytes from or to the specified C<$fh> and
411C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 454C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
412and calls the callback without the actual number of bytes read (or -1 on 455calls the callback with the actual number of bytes transferred (or -1 on
413error, just like the syscall). 456error, just like the syscall).
414 457
415C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 458C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
416offset plus the actual number of bytes read. 459offset plus the actual number of bytes read.
417 460
475As native sendfile syscalls (as practically any non-POSIX interface hacked 518As native sendfile syscalls (as practically any non-POSIX interface hacked
476together in a hurry to improve benchmark numbers) tend to be rather buggy 519together in a hurry to improve benchmark numbers) tend to be rather buggy
477on many systems, this implementation tries to work around some known bugs 520on many systems, this implementation tries to work around some known bugs
478in Linux and FreeBSD kernels (probably others, too), but that might fail, 521in Linux and FreeBSD kernels (probably others, too), but that might fail,
479so you really really should check the return value of C<aio_sendfile> - 522so you really really should check the return value of C<aio_sendfile> -
480fewre bytes than expected might have been transferred. 523fewer bytes than expected might have been transferred.
481 524
482 525
483=item aio_readahead $fh,$offset,$length, $callback->($retval) 526=item aio_readahead $fh,$offset,$length, $callback->($retval)
484 527
485C<aio_readahead> populates the page cache with data from a file so that 528C<aio_readahead> populates the page cache with data from a file so that
489whole pages, so that offset is effectively rounded down to a page boundary 532whole pages, so that offset is effectively rounded down to a page boundary
490and bytes are read up to the next page boundary greater than or equal to 533and bytes are read up to the next page boundary greater than or equal to
491(off-set+length). C<aio_readahead> does not read beyond the end of the 534(off-set+length). C<aio_readahead> does not read beyond the end of the
492file. The current file offset of the file is left unchanged. 535file. The current file offset of the file is left unchanged.
493 536
494If that syscall doesn't exist (likely if your OS isn't Linux) it will be 537If that syscall doesn't exist (likely if your kernel isn't Linux) it will
495emulated by simply reading the data, which would have a similar effect. 538be emulated by simply reading the data, which would have a similar effect.
496 539
497 540
498=item aio_stat $fh_or_path, $callback->($status) 541=item aio_stat $fh_or_path, $callback->($status)
499 542
500=item aio_lstat $fh, $callback->($status) 543=item aio_lstat $fh, $callback->($status)
569 namemax => 255, 612 namemax => 255,
570 frsize => 1024, 613 frsize => 1024,
571 fsid => 1810 614 fsid => 1810
572 } 615 }
573 616
574
575=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 617=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
576 618
577Works like perl's C<utime> function (including the special case of $atime 619Works like perl's C<utime> function (including the special case of $atime
578and $mtime being undef). Fractional times are supported if the underlying 620and $mtime being undef). Fractional times are supported if the underlying
579syscalls support them. 621syscalls support them.
606=item aio_truncate $fh_or_path, $offset, $callback->($status) 648=item aio_truncate $fh_or_path, $offset, $callback->($status)
607 649
608Works like truncate(2) or ftruncate(2). 650Works like truncate(2) or ftruncate(2).
609 651
610 652
653=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
654
655Allocates or frees disk space according to the C<$mode> argument. See the
656linux C<fallocate> documentation for details.
657
658C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
659space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
660to deallocate a file range.
661
662IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
663(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
664C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
665to unshare shared blocks (see your L<fallocate(2)> manpage).
666
667The file system block size used by C<fallocate> is presumably the
668C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
669can dictate other limitations.
670
671If C<fallocate> isn't available or cannot be emulated (currently no
672emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
673
674
611=item aio_chmod $fh_or_path, $mode, $callback->($status) 675=item aio_chmod $fh_or_path, $mode, $callback->($status)
612 676
613Works like perl's C<chmod> function. 677Works like perl's C<chmod> function.
614 678
615 679
652 716
653 717
654=item aio_realpath $pathname, $callback->($path) 718=item aio_realpath $pathname, $callback->($path)
655 719
656Asynchronously make the path absolute and resolve any symlinks in 720Asynchronously make the path absolute and resolve any symlinks in
657C<$path>. The resulting path only consists of directories (Same as 721C<$path>. The resulting path only consists of directories (same as
658L<Cwd::realpath>). 722L<Cwd::realpath>).
659 723
660This request can be used to get the absolute path of the current working 724This request can be used to get the absolute path of the current working
661directory by passing it a path of F<.> (a single dot). 725directory by passing it a path of F<.> (a single dot).
662 726
663 727
664=item aio_rename $srcpath, $dstpath, $callback->($status) 728=item aio_rename $srcpath, $dstpath, $callback->($status)
665 729
666Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 730Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
667rename(2) and call the callback with the result code. 731rename(2) and call the callback with the result code.
732
733On systems that support the AIO::WD working directory abstraction
734natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
735of failing, C<rename> is called on the absolute path of C<$wd>.
736
737
738=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
739
740Basically a version of C<aio_rename> with an additional C<$flags>
741argument. Calling this with C<$flags=0> is the same as calling
742C<aio_rename>.
743
744Non-zero flags are currently only supported on GNU/Linux systems that
745support renameat2. Other systems fail with C<ENOSYS> in this case.
746
747The following constants are available (missing ones are, as usual C<0>),
748see renameat2(2) for details:
749
750C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
751and C<IO::AIO::RENAME_WHITEOUT>.
668 752
669 753
670=item aio_mkdir $pathname, $mode, $callback->($status) 754=item aio_mkdir $pathname, $mode, $callback->($status)
671 755
672Asynchronously mkdir (create) a directory and call the callback with 756Asynchronously mkdir (create) a directory and call the callback with
676 760
677=item aio_rmdir $pathname, $callback->($status) 761=item aio_rmdir $pathname, $callback->($status)
678 762
679Asynchronously rmdir (delete) a directory and call the callback with the 763Asynchronously rmdir (delete) a directory and call the callback with the
680result code. 764result code.
765
766On systems that support the AIO::WD working directory abstraction
767natively, the case C<[$wd, "."]> is specialcased - instead of failing,
768C<rmdir> is called on the absolute path of C<$wd>.
681 769
682 770
683=item aio_readdir $pathname, $callback->($entries) 771=item aio_readdir $pathname, $callback->($entries)
684 772
685Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 773Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
754C<$type>'s are known, which can be used to speed up some algorithms. 842C<$type>'s are known, which can be used to speed up some algorithms.
755 843
756=back 844=back
757 845
758 846
847=item aio_slurp $pathname, $offset, $length, $data, $callback->($status)
848
849Opens, reads and closes the given file. The data is put into C<$data>,
850which is resized as required.
851
852If C<$offset> is negative, then it is counted from the end of the file.
853
854If C<$length> is zero, then the remaining length of the file is
855used. Also, in this case, the same limitations to modifying C<$data> apply
856as when IO::AIO::mmap is used, i.e. it must only be modified in-place
857with C<substr>. If the size of the file is known, specifying a non-zero
858C<$length> results in a performance advantage.
859
860This request is similar to the older C<aio_load> request, but since it is
861a single request, it might be more efficient to use.
862
863Example: load F</etc/passwd> into C<$passwd>.
864
865 my $passwd;
866 aio_slurp "/etc/passwd", 0, 0, $passwd, sub {
867 $_[0] >= 0
868 or die "/etc/passwd: $!\n";
869
870 printf "/etc/passwd is %d bytes long, and contains:\n", length $passwd;
871 print $passwd;
872 };
873 IO::AIO::flush;
874
875
759=item aio_load $pathname, $data, $callback->($status) 876=item aio_load $pathname, $data, $callback->($status)
760 877
761This is a composite request that tries to fully load the given file into 878This is a composite request that tries to fully load the given file into
762memory. Status is the same as with aio_read. 879memory. Status is the same as with aio_read.
880
881Using C<aio_slurp> might be more efficient, as it is a single request.
763 882
764=cut 883=cut
765 884
766sub aio_load($$;$) { 885sub aio_load($$;$) {
767 my ($path, undef, $cb) = @_; 886 my ($path, undef, $cb) = @_;
787=item aio_copy $srcpath, $dstpath, $callback->($status) 906=item aio_copy $srcpath, $dstpath, $callback->($status)
788 907
789Try to copy the I<file> (directories not supported as either source or 908Try to copy the I<file> (directories not supported as either source or
790destination) from C<$srcpath> to C<$dstpath> and call the callback with 909destination) from C<$srcpath> to C<$dstpath> and call the callback with
791a status of C<0> (ok) or C<-1> (error, see C<$!>). 910a status of C<0> (ok) or C<-1> (error, see C<$!>).
911
912Existing destination files will be truncated.
792 913
793This is a composite request that creates the destination file with 914This is a composite request that creates the destination file with
794mode 0200 and copies the contents of the source file into it using 915mode 0200 and copies the contents of the source file into it using
795C<aio_sendfile>, followed by restoring atime, mtime, access mode and 916C<aio_sendfile>, followed by restoring atime, mtime, access mode and
796uid/gid, in that order. 917uid/gid, in that order.
906Scans a directory (similar to C<aio_readdir>) but additionally tries to 1027Scans a directory (similar to C<aio_readdir>) but additionally tries to
907efficiently separate the entries of directory C<$path> into two sets of 1028efficiently separate the entries of directory C<$path> into two sets of
908names, directories you can recurse into (directories), and ones you cannot 1029names, directories you can recurse into (directories), and ones you cannot
909recurse into (everything else, including symlinks to directories). 1030recurse into (everything else, including symlinks to directories).
910 1031
911C<aio_scandir> is a composite request that creates of many sub requests_ 1032C<aio_scandir> is a composite request that generates many sub requests.
912C<$maxreq> specifies the maximum number of outstanding aio requests that 1033C<$maxreq> specifies the maximum number of outstanding aio requests that
913this function generates. If it is C<< <= 0 >>, then a suitable default 1034this function generates. If it is C<< <= 0 >>, then a suitable default
914will be chosen (currently 4). 1035will be chosen (currently 4).
915 1036
916On error, the callback is called without arguments, otherwise it receives 1037On error, the callback is called without arguments, otherwise it receives
966 1087
967 my $grp = aio_group $cb; 1088 my $grp = aio_group $cb;
968 1089
969 $maxreq = 4 if $maxreq <= 0; 1090 $maxreq = 4 if $maxreq <= 0;
970 1091
971 # stat once 1092 # get a wd object
972 aioreq_pri $pri; 1093 aioreq_pri $pri;
973 add $grp aio_stat $path, sub { 1094 add $grp aio_wd $path, sub {
1095 $_[0]
974 return $grp->result () if $_[0]; 1096 or return $grp->result ();
975 my $now = time;
976 my $hash1 = join ":", (stat _)[0,1,3,7,9];
977 1097
978 # read the directory entries 1098 my $wd = [shift, "."];
1099
1100 # stat once
979 aioreq_pri $pri; 1101 aioreq_pri $pri;
980 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1102 add $grp aio_stat $wd, sub {
981 my $entries = shift
982 or return $grp->result (); 1103 return $grp->result () if $_[0];
1104 my $now = time;
1105 my $hash1 = join ":", (stat _)[0,1,3,7,9];
983 1106
984 # stat the dir another time 1107 # read the directory entries
985 aioreq_pri $pri; 1108 aioreq_pri $pri;
1109 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
1110 my $entries = shift
1111 or return $grp->result ();
1112
1113 # stat the dir another time
1114 aioreq_pri $pri;
986 add $grp aio_stat $path, sub { 1115 add $grp aio_stat $wd, sub {
987 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1116 my $hash2 = join ":", (stat _)[0,1,3,7,9];
988 1117
989 my $ndirs; 1118 my $ndirs;
990 1119
991 # take the slow route if anything looks fishy 1120 # take the slow route if anything looks fishy
992 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1121 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
993 $ndirs = -1; 1122 $ndirs = -1;
994 } else { 1123 } else {
995 # if nlink == 2, we are finished 1124 # if nlink == 2, we are finished
996 # for non-posix-fs's, we rely on nlink < 2 1125 # for non-posix-fs's, we rely on nlink < 2
997 $ndirs = (stat _)[3] - 2 1126 $ndirs = (stat _)[3] - 2
998 or return $grp->result ([], $entries); 1127 or return $grp->result ([], $entries);
999 } 1128 }
1000 1129
1001 my (@dirs, @nondirs); 1130 my (@dirs, @nondirs);
1002 1131
1003 my $statgrp = add $grp aio_group sub { 1132 my $statgrp = add $grp aio_group sub {
1004 $grp->result (\@dirs, \@nondirs); 1133 $grp->result (\@dirs, \@nondirs);
1005 }; 1134 };
1006 1135
1007 limit $statgrp $maxreq; 1136 limit $statgrp $maxreq;
1008 feed $statgrp sub { 1137 feed $statgrp sub {
1009 return unless @$entries; 1138 return unless @$entries;
1010 my $entry = shift @$entries; 1139 my $entry = shift @$entries;
1011 1140
1012 aioreq_pri $pri; 1141 aioreq_pri $pri;
1142 $wd->[1] = "$entry/.";
1013 add $statgrp aio_stat "$path/$entry/.", sub { 1143 add $statgrp aio_stat $wd, sub {
1014 if ($_[0] < 0) { 1144 if ($_[0] < 0) {
1015 push @nondirs, $entry; 1145 push @nondirs, $entry;
1016 } else { 1146 } else {
1017 # need to check for real directory 1147 # need to check for real directory
1018 aioreq_pri $pri; 1148 aioreq_pri $pri;
1149 $wd->[1] = $entry;
1019 add $statgrp aio_lstat "$path/$entry", sub { 1150 add $statgrp aio_lstat $wd, sub {
1020 if (-d _) { 1151 if (-d _) {
1021 push @dirs, $entry; 1152 push @dirs, $entry;
1022 1153
1023 unless (--$ndirs) { 1154 unless (--$ndirs) {
1024 push @nondirs, @$entries; 1155 push @nondirs, @$entries;
1025 feed $statgrp; 1156 feed $statgrp;
1157 }
1158 } else {
1159 push @nondirs, $entry;
1026 } 1160 }
1027 } else {
1028 push @nondirs, $entry;
1029 } 1161 }
1030 } 1162 }
1031 } 1163 };
1032 }; 1164 };
1033 }; 1165 };
1034 }; 1166 };
1035 }; 1167 };
1036 }; 1168 };
1039} 1171}
1040 1172
1041=item aio_rmtree $pathname, $callback->($status) 1173=item aio_rmtree $pathname, $callback->($status)
1042 1174
1043Delete a directory tree starting (and including) C<$path>, return the 1175Delete a directory tree starting (and including) C<$path>, return the
1044status of the final C<rmdir> only. This is a composite request that 1176status of the final C<rmdir> only. This is a composite request that
1045uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1177uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1046everything else. 1178everything else.
1047 1179
1048=cut 1180=cut
1049 1181
1070 add $grp $dirgrp; 1202 add $grp $dirgrp;
1071 }; 1203 };
1072 1204
1073 $grp 1205 $grp
1074} 1206}
1207
1208=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1209
1210=item aio_ioctl $fh, $request, $buf, $callback->($status)
1211
1212These work just like the C<fcntl> and C<ioctl> built-in functions, except
1213they execute asynchronously and pass the return value to the callback.
1214
1215Both calls can be used for a lot of things, some of which make more sense
1216to run asynchronously in their own thread, while some others make less
1217sense. For example, calls that block waiting for external events, such
1218as locking, will also lock down an I/O thread while it is waiting, which
1219can deadlock the whole I/O system. At the same time, there might be no
1220alternative to using a thread to wait.
1221
1222So in general, you should only use these calls for things that do
1223(filesystem) I/O, not for things that wait for other events (network,
1224other processes), although if you are careful and know what you are doing,
1225you still can.
1226
1227The following constants are available (missing ones are, as usual C<0>):
1228
1229C<F_DUPFD_CLOEXEC>,
1230
1231C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1232
1233C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1234
1235C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1236C<FS_IOC_FIEMAP>.
1237
1238C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1239C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1240
1241C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1242C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1243C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1244C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1245C<FS_FL_USER_MODIFIABLE>.
1246
1247C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1248C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1249C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1250C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1075 1251
1076=item aio_sync $callback->($status) 1252=item aio_sync $callback->($status)
1077 1253
1078Asynchronously call sync and call the callback when finished. 1254Asynchronously call sync and call the callback when finished.
1079 1255
1148 }; 1324 };
1149 1325
1150 $grp 1326 $grp
1151} 1327}
1152 1328
1153=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1329=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1154 1330
1155This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1331This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1156scalars (see the C<IO::AIO::mmap> function, although it also works on data 1332scalars (see the C<IO::AIO::mmap> function, although it also works on data
1157scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1333scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1158scalar must only be modified in-place while an aio operation is pending on 1334scalar must only be modified in-place while an aio operation is pending on
1160 1336
1161It calls the C<msync> function of your OS, if available, with the memory 1337It calls the C<msync> function of your OS, if available, with the memory
1162area starting at C<$offset> in the string and ending C<$length> bytes 1338area starting at C<$offset> in the string and ending C<$length> bytes
1163later. If C<$length> is negative, counts from the end, and if C<$length> 1339later. If C<$length> is negative, counts from the end, and if C<$length>
1164is C<undef>, then it goes till the end of the string. The flags can be 1340is C<undef>, then it goes till the end of the string. The flags can be
1165a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1341either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1166C<IO::AIO::MS_SYNC>. 1342C<IO::AIO::MS_INVALIDATE>.
1167 1343
1168=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1344=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1169 1345
1170This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1346This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1171scalars. 1347scalars.
1172 1348
1173It touches (reads or writes) all memory pages in the specified 1349It touches (reads or writes) all memory pages in the specified
1174range inside the scalar. All caveats and parameters are the same 1350range inside the scalar. All caveats and parameters are the same
1175as for C<aio_msync>, above, except for flags, which must be either 1351as for C<aio_msync>, above, except for flags, which must be either
1176C<0> (which reads all pages and ensures they are instantiated) or 1352C<0> (which reads all pages and ensures they are instantiated) or
1177C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1353C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1178writing an octet from it, which dirties the page). 1354writing an octet from it, which dirties the page).
1179 1355
1180=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 1356=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1181 1357
1182This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1358This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1213documented under L<MISCELLANEOUS FUNCTIONS>. 1389documented under L<MISCELLANEOUS FUNCTIONS>.
1214 1390
1215Example: asynchronously lock all current and future pages into memory. 1391Example: asynchronously lock all current and future pages into memory.
1216 1392
1217 aio_mlockall IO::AIO::MCL_FUTURE; 1393 aio_mlockall IO::AIO::MCL_FUTURE;
1394
1395=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1396
1397Queries the extents of the given file (by calling the Linux C<FIEMAP>
1398ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1399the ioctl is not available on your OS, then this request will fail with
1400C<ENOSYS>.
1401
1402C<$start> is the starting offset to query extents for, C<$length> is the
1403size of the range to query - if it is C<undef>, then the whole file will
1404be queried.
1405
1406C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1407C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1408exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1409the data portion.
1410
1411C<$count> is the maximum number of extent records to return. If it is
1412C<undef>, then IO::AIO queries all extents of the range. As a very special
1413case, if it is C<0>, then the callback receives the number of extents
1414instead of the extents themselves (which is unreliable, see below).
1415
1416If an error occurs, the callback receives no arguments. The special
1417C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1418
1419Otherwise, the callback receives an array reference with extent
1420structures. Each extent structure is an array reference itself, with the
1421following members:
1422
1423 [$logical, $physical, $length, $flags]
1424
1425Flags is any combination of the following flag values (typically either C<0>
1426or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1427
1428C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1429C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1430C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1431C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1432C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1433C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1434
1435At the time of this writing (Linux 3.2), this request is unreliable unless
1436C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1437it to return all extents of a range for files with a large number of
1438extents. The code (only) works around all these issues if C<$count> is
1439C<undef>.
1218 1440
1219=item aio_group $callback->(...) 1441=item aio_group $callback->(...)
1220 1442
1221This is a very special aio request: Instead of doing something, it is a 1443This is a very special aio request: Instead of doing something, it is a
1222container for other aio requests, which is useful if you want to bundle 1444container for other aio requests, which is useful if you want to bundle
1286object. This object stores the canonicalised, absolute version of the 1508object. This object stores the canonicalised, absolute version of the
1287path, and on systems that allow it, also a directory file descriptor. 1509path, and on systems that allow it, also a directory file descriptor.
1288 1510
1289Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat> 1511Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1290or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD 1512or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1291object and a pathname instead. If the pathname is absolute, the 1513object and a pathname instead (or the IO::AIO::WD object alone, which
1514gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1292IO::AIO::WD objetc is ignored, otherwise the pathname is resolved relative 1515IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1293to that IO::AIO::WD object. 1516to that IO::AIO::WD object.
1294 1517
1295For example, to get a wd object for F</etc> and then stat F<passwd> 1518For example, to get a wd object for F</etc> and then stat F<passwd>
1296inside, you would write: 1519inside, you would write:
1297 1520
1305 aio_stat [$etcdir, "passwd"], sub { 1528 aio_stat [$etcdir, "passwd"], sub {
1306 # yay 1529 # yay
1307 }; 1530 };
1308 }; 1531 };
1309 1532
1533The fact that C<aio_wd> is a request and not a normal function shows that
1310This shows that creating an IO::AIO::WD object is itself a potentially 1534creating an IO::AIO::WD object is itself a potentially blocking operation,
1311blocking operation, which is why it is done asynchronously. 1535which is why it is done asynchronously.
1536
1537To stat the directory obtained with C<aio_wd> above, one could write
1538either of the following three request calls:
1539
1540 aio_lstat "/etc" , sub { ... # pathname as normal string
1541 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1542 aio_lstat $wd , sub { ... # shorthand for the previous
1312 1543
1313As with normal pathnames, IO::AIO keeps a copy of the working directory 1544As with normal pathnames, IO::AIO keeps a copy of the working directory
1314object and the pathname string, so you could write the following without 1545object and the pathname string, so you could write the following without
1315causing any issues due to C<$path> getting reused: 1546causing any issues due to C<$path> getting reused:
1316 1547
1326There are some caveats: when directories get renamed (or deleted), the 1557There are some caveats: when directories get renamed (or deleted), the
1327pathname string doesn't change, so will point to the new directory (or 1558pathname string doesn't change, so will point to the new directory (or
1328nowhere at all), while the directory fd, if available on the system, 1559nowhere at all), while the directory fd, if available on the system,
1329will still point to the original directory. Most functions accepting a 1560will still point to the original directory. Most functions accepting a
1330pathname will use the directory fd on newer systems, and the string on 1561pathname will use the directory fd on newer systems, and the string on
1331older systems. Some functions (such as realpath) will always rely on the 1562older systems. Some functions (such as C<aio_realpath>) will always rely on
1332string form of the pathname. 1563the string form of the pathname.
1333 1564
1334So this fucntionality is mainly useful to get some protection against 1565So this functionality is mainly useful to get some protection against
1335C<chdir>, to easily get an absolute path out of a relative path for future 1566C<chdir>, to easily get an absolute path out of a relative path for future
1336reference, and to speed up doing many operations in the same directory 1567reference, and to speed up doing many operations in the same directory
1337(e.g. when stat'ing all files in a directory). 1568(e.g. when stat'ing all files in a directory).
1338 1569
1339The following functions implement this working directory abstraction: 1570The following functions implement this working directory abstraction:
1352passing C<undef> as working directory component of a pathname fails the 1583passing C<undef> as working directory component of a pathname fails the
1353request with C<ENOENT>, there is often no need for error checking in the 1584request with C<ENOENT>, there is often no need for error checking in the
1354C<aio_wd> callback, as future requests using the value will fail in the 1585C<aio_wd> callback, as future requests using the value will fail in the
1355expected way. 1586expected way.
1356 1587
1357If this call isn't available because your OS lacks it or it couldn't be
1358detected, it will be emulated by calling C<fsync> instead.
1359
1360=item IO::AIO::CWD 1588=item IO::AIO::CWD
1361 1589
1362This is a compiletime constant (object) that represents the process 1590This is a compiletime constant (object) that represents the process
1363current working directory. 1591current working directory.
1364 1592
1365Specifying this object as working directory object for a pathname is as 1593Specifying this object as working directory object for a pathname is as if
1366if the pathname would be specified directly, without a directory object, 1594the pathname would be specified directly, without a directory object. For
1367e.g., these calls are functionally identical: 1595example, these calls are functionally identical:
1368 1596
1369 aio_stat "somefile", sub { ... }; 1597 aio_stat "somefile", sub { ... };
1370 aio_stat [IO::AIO::CWD, "somefile"], sub { ... }; 1598 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1371 1599
1372=back 1600=back
1373 1601
1602To recover the path associated with an IO::AIO::WD object, you can use
1603C<aio_realpath>:
1604
1605 aio_realpath $wd, sub {
1606 warn "path is $_[0]\n";
1607 };
1608
1609Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1610sometimes, fall back to using an absolue path.
1374 1611
1375=head2 IO::AIO::REQ CLASS 1612=head2 IO::AIO::REQ CLASS
1376 1613
1377All non-aggregate C<aio_*> functions return an object of this class when 1614All non-aggregate C<aio_*> functions return an object of this class when
1378called in non-void context. 1615called in non-void context.
1496 1733
1497Sets a feeder/generator on this group: every group can have an attached 1734Sets a feeder/generator on this group: every group can have an attached
1498generator that generates requests if idle. The idea behind this is that, 1735generator that generates requests if idle. The idea behind this is that,
1499although you could just queue as many requests as you want in a group, 1736although you could just queue as many requests as you want in a group,
1500this might starve other requests for a potentially long time. For example, 1737this might starve other requests for a potentially long time. For example,
1501C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1738C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1502delaying any later requests for a long time. 1739requests, delaying any later requests for a long time.
1503 1740
1504To avoid this, and allow incremental generation of requests, you can 1741To avoid this, and allow incremental generation of requests, you can
1505instead a group and set a feeder on it that generates those requests. The 1742instead a group and set a feeder on it that generates those requests. The
1506feed callback will be called whenever there are few enough (see C<limit>, 1743feed callback will be called whenever there are few enough (see C<limit>,
1507below) requests active in the group itself and is expected to queue more 1744below) requests active in the group itself and is expected to queue more
1556 1793
1557See C<poll_cb> for an example. 1794See C<poll_cb> for an example.
1558 1795
1559=item IO::AIO::poll_cb 1796=item IO::AIO::poll_cb
1560 1797
1561Process some outstanding events on the result pipe. You have to call 1798Process some requests that have reached the result phase (i.e. they have
1799been executed but the results are not yet reported). You have to call
1800this "regularly" to finish outstanding requests.
1801
1562this regularly. Returns C<0> if all events could be processed (or there 1802Returns C<0> if all events could be processed (or there were no
1563were no events to process), or C<-1> if it returned earlier for whatever 1803events to process), or C<-1> if it returned earlier for whatever
1564reason. Returns immediately when no events are outstanding. The amount of 1804reason. Returns immediately when no events are outstanding. The amount
1565events processed depends on the settings of C<IO::AIO::max_poll_req> and 1805of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1566C<IO::AIO::max_poll_time>. 1806C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1567 1807
1568If not all requests were processed for whatever reason, the filehandle 1808If not all requests were processed for whatever reason, the poll file
1569will still be ready when C<poll_cb> returns, so normally you don't have to 1809descriptor will still be ready when C<poll_cb> returns, so normally you
1570do anything special to have it called later. 1810don't have to do anything special to have it called later.
1571 1811
1572Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes 1812Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1573ready, it can be beneficial to call this function from loops which submit 1813ready, it can be beneficial to call this function from loops which submit
1574a lot of requests, to make sure the results get processed when they become 1814a lot of requests, to make sure the results get processed when they become
1575available and not just when the loop is finished and the event loop takes 1815available and not just when the loop is finished and the event loop takes
1584 poll => 'r', async => 1, 1824 poll => 'r', async => 1,
1585 cb => \&IO::AIO::poll_cb); 1825 cb => \&IO::AIO::poll_cb);
1586 1826
1587=item IO::AIO::poll_wait 1827=item IO::AIO::poll_wait
1588 1828
1589If there are any outstanding requests and none of them in the result 1829Wait until either at least one request is in the result phase or no
1590phase, wait till the result filehandle becomes ready for reading (simply 1830requests are outstanding anymore.
1591does a C<select> on the filehandle. This is useful if you want to 1831
1592synchronously wait for some requests to finish). 1832This is useful if you want to synchronously wait for some requests to
1833become ready, without actually handling them.
1593 1834
1594See C<nreqs> for an example. 1835See C<nreqs> for an example.
1595 1836
1596=item IO::AIO::poll 1837=item IO::AIO::poll
1597 1838
1718 1959
1719This is a very bad function to use in interactive programs because it 1960This is a very bad function to use in interactive programs because it
1720blocks, and a bad way to reduce concurrency because it is inexact: Better 1961blocks, and a bad way to reduce concurrency because it is inexact: Better
1721use an C<aio_group> together with a feed callback. 1962use an C<aio_group> together with a feed callback.
1722 1963
1723It's main use is in scripts without an event loop - when you want to stat 1964Its main use is in scripts without an event loop - when you want to stat
1724a lot of files, you can write somehting like this: 1965a lot of files, you can write something like this:
1725 1966
1726 IO::AIO::max_outstanding 32; 1967 IO::AIO::max_outstanding 32;
1727 1968
1728 for my $path (...) { 1969 for my $path (...) {
1729 aio_stat $path , ...; 1970 aio_stat $path , ...;
1768 2009
1769=back 2010=back
1770 2011
1771=head3 MISCELLANEOUS FUNCTIONS 2012=head3 MISCELLANEOUS FUNCTIONS
1772 2013
1773IO::AIO implements some functions that might be useful, but are not 2014IO::AIO implements some functions that are useful when you want to use
1774asynchronous. 2015some "Advanced I/O" function not available to in Perl, without going the
2016"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2017counterpart.
1775 2018
1776=over 4 2019=over 4
2020
2021=item $numfd = IO::AIO::get_fdlimit
2022
2023This function is I<EXPERIMENTAL> and subject to change.
2024
2025Tries to find the current file descriptor limit and returns it, or
2026C<undef> and sets C<$!> in case of an error. The limit is one larger than
2027the highest valid file descriptor number.
2028
2029=item IO::AIO::min_fdlimit [$numfd]
2030
2031This function is I<EXPERIMENTAL> and subject to change.
2032
2033Try to increase the current file descriptor limit(s) to at least C<$numfd>
2034by changing the soft or hard file descriptor resource limit. If C<$numfd>
2035is missing, it will try to set a very high limit, although this is not
2036recommended when you know the actual minimum that you require.
2037
2038If the limit cannot be raised enough, the function makes a best-effort
2039attempt to increase the limit as much as possible, using various
2040tricks, while still failing. You can query the resulting limit using
2041C<IO::AIO::get_fdlimit>.
2042
2043If an error occurs, returns C<undef> and sets C<$!>, otherwise returns
2044true.
1777 2045
1778=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2046=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1779 2047
1780Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2048Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1781but is blocking (this makes most sense if you know the input data is 2049but is blocking (this makes most sense if you know the input data is
1798=item IO::AIO::madvise $scalar, $offset, $len, $advice 2066=item IO::AIO::madvise $scalar, $offset, $len, $advice
1799 2067
1800Simply calls the C<posix_madvise> function (see its 2068Simply calls the C<posix_madvise> function (see its
1801manpage for details). The following advice constants are 2069manpage for details). The following advice constants are
1802available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2070available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1803C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2071C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2072C<IO::AIO::MADV_DONTNEED>.
2073
2074If C<$offset> is negative, counts from the end. If C<$length> is negative,
2075the remaining length of the C<$scalar> is used. If possible, C<$length>
2076will be reduced to fit into the C<$scalar>.
1804 2077
1805On systems that do not implement C<posix_madvise>, this function returns 2078On systems that do not implement C<posix_madvise>, this function returns
1806ENOSYS, otherwise the return value of C<posix_madvise>. 2079ENOSYS, otherwise the return value of C<posix_madvise>.
1807 2080
1808=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2081=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1810Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2083Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1811$scalar (see its manpage for details). The following protect 2084$scalar (see its manpage for details). The following protect
1812constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2085constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1813C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2086C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1814 2087
2088If C<$offset> is negative, counts from the end. If C<$length> is negative,
2089the remaining length of the C<$scalar> is used. If possible, C<$length>
2090will be reduced to fit into the C<$scalar>.
2091
1815On systems that do not implement C<mprotect>, this function returns 2092On systems that do not implement C<mprotect>, this function returns
1816ENOSYS, otherwise the return value of C<mprotect>. 2093ENOSYS, otherwise the return value of C<mprotect>.
1817 2094
1818=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2095=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1819 2096
1820Memory-maps a file (or anonymous memory range) and attaches it to the 2097Memory-maps a file (or anonymous memory range) and attaches it to the
1821given C<$scalar>, which will act like a string scalar. 2098given C<$scalar>, which will act like a string scalar. Returns true on
2099success, and false otherwise.
1822 2100
2101The scalar must exist, but its contents do not matter - this means you
2102cannot use a nonexistant array or hash element. When in doubt, C<undef>
2103the scalar first.
2104
1823The only operations allowed on the scalar are C<substr>/C<vec> that don't 2105The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
1824change the string length, and most read-only operations such as copying it 2106which don't change the string length, and most read-only operations such
1825or searching it with regexes and so on. 2107as copying it or searching it with regexes and so on.
1826 2108
1827Anything else is unsafe and will, at best, result in memory leaks. 2109Anything else is unsafe and will, at best, result in memory leaks.
1828 2110
1829The memory map associated with the C<$scalar> is automatically removed 2111The memory map associated with the C<$scalar> is automatically removed
1830when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2112when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
1831C<IO::AIO::munmap> functions are called. 2113or C<IO::AIO::munmap> functions are called on it.
1832 2114
1833This calls the C<mmap>(2) function internally. See your system's manual 2115This calls the C<mmap>(2) function internally. See your system's manual
1834page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2116page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1835 2117
1836The C<$length> must be larger than zero and smaller than the actual 2118The C<$length> must be larger than zero and smaller than the actual
1837filesize. 2119filesize.
1838 2120
1839C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2121C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1840C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2122C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1841 2123
1842C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2124C<$flags> can be a combination of
1843C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2125C<IO::AIO::MAP_SHARED> or
1844not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2126C<IO::AIO::MAP_PRIVATE>,
2127or a number of system-specific flags (when not available, the are C<0>):
1845(which is set to C<MAP_ANON> if your system only provides this 2128C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
1846constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2129C<IO::AIO::MAP_LOCKED>,
1847C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2130C<IO::AIO::MAP_NORESERVE>,
2131C<IO::AIO::MAP_POPULATE>,
1848C<IO::AIO::MAP_NONBLOCK> 2132C<IO::AIO::MAP_NONBLOCK>,
2133C<IO::AIO::MAP_FIXED>,
2134C<IO::AIO::MAP_GROWSDOWN>,
2135C<IO::AIO::MAP_32BIT>,
2136C<IO::AIO::MAP_HUGETLB> or
2137C<IO::AIO::MAP_STACK>.
1849 2138
1850If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2139If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1851 2140
1852C<$offset> is the offset from the start of the file - it generally must be 2141C<$offset> is the offset from the start of the file - it generally must be
1853a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2142a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1878 2167
1879Calls the C<munlockall> function. 2168Calls the C<munlockall> function.
1880 2169
1881On systems that do not implement C<munlockall>, this function returns 2170On systems that do not implement C<munlockall>, this function returns
1882ENOSYS, otherwise the return value of C<munlockall>. 2171ENOSYS, otherwise the return value of C<munlockall>.
2172
2173=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2174
2175Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2176C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2177should be the file offset.
2178
2179C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2180silently corrupt the data in this case.
2181
2182The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2183C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2184C<IO::AIO::SPLICE_F_GIFT>.
2185
2186See the C<splice(2)> manpage for details.
2187
2188=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2189
2190Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2191description for C<IO::AIO::splice> above for details.
2192
2193=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2194
2195Attempts to query or change the pipe buffer size. Obviously works only
2196on pipes, and currently works only on GNU/Linux systems, and fails with
2197C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2198size on other systems, drop me a note.
2199
2200=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2201
2202This is a direct interface to the Linux L<pipe2(2)> system call. If
2203C<$flags> is missing or C<0>, then this should be the same as a call to
2204perl's built-in C<pipe> function and create a new pipe, and works on
2205systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2206(..., 4096, O_BINARY)>.
2207
2208If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2209the given flags (Linux 2.6.27, glibc 2.9).
2210
2211On success, the read and write file handles are returned.
2212
2213On error, nothing will be returned. If the pipe2 syscall is missing and
2214C<$flags> is non-zero, fails with C<ENOSYS>.
2215
2216Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2217time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2218C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
1883 2219
1884=back 2220=back
1885 2221
1886=cut 2222=cut
1887 2223

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