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Revision 1.115 by root, Mon Sep 24 18:14:00 2007 UTC vs.
Revision 1.229 by root, Wed Jul 25 16:32:30 2012 UTC

4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub { 9 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
10 my $fh = shift 10 my $fh = shift
11 or die "/etc/passwd: $!"; 11 or die "/etc/passwd: $!";
12 ... 12 ...
13 }; 13 };
14 14
26 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
27 27
28 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
29 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
30 30
31 # AnyEvent integration
32 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
33 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
34
35 # Event integration
36 Event->io (fd => IO::AIO::poll_fileno,
37 poll => 'r',
38 cb => \&IO::AIO::poll_cb);
39
40 # Glib/Gtk2 integration
41 add_watch Glib::IO IO::AIO::poll_fileno,
42 in => sub { IO::AIO::poll_cb; 1 };
43
44 # Tk integration
45 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
46 readable => \&IO::AIO::poll_cb);
47
48 # Danga::Socket integration
49 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
50 \&IO::AIO::poll_cb);
51
52=head1 DESCRIPTION 31=head1 DESCRIPTION
53 32
54This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
55operating system supports. 34operating system supports. It is implemented as an interface to C<libeio>
35(L<http://software.schmorp.de/pkg/libeio.html>).
56 36
57Asynchronous means that operations that can normally block your program 37Asynchronous means that operations that can normally block your program
58(e.g. reading from disk) will be done asynchronously: the operation 38(e.g. reading from disk) will be done asynchronously: the operation
59will still block, but you can do something else in the meantime. This 39will still block, but you can do something else in the meantime. This
60is extremely useful for programs that need to stay interactive even 40is extremely useful for programs that need to stay interactive even
64on a RAID volume or over NFS when you do a number of stat operations 44on a RAID volume or over NFS when you do a number of stat operations
65concurrently. 45concurrently.
66 46
67While most of this works on all types of file descriptors (for 47While most of this works on all types of file descriptors (for
68example sockets), using these functions on file descriptors that 48example sockets), using these functions on file descriptors that
69support nonblocking operation (again, sockets, pipes etc.) is very 49support nonblocking operation (again, sockets, pipes etc.) is
70inefficient. Use an event loop for that (such as the L<Event|Event> 50very inefficient. Use an event loop for that (such as the L<EV>
71module): IO::AIO will naturally fit into such an event loop itself. 51module): IO::AIO will naturally fit into such an event loop itself.
72 52
73In this version, a number of threads are started that execute your 53In this version, a number of threads are started that execute your
74requests and signal their completion. You don't need thread support 54requests and signal their completion. You don't need thread support
75in perl, and the threads created by this module will not be visible 55in perl, and the threads created by this module will not be visible
85yourself, always call C<poll_cb> from within the same thread, or never 65yourself, always call C<poll_cb> from within the same thread, or never
86call C<poll_cb> (or other C<aio_> functions) recursively. 66call C<poll_cb> (or other C<aio_> functions) recursively.
87 67
88=head2 EXAMPLE 68=head2 EXAMPLE
89 69
90This is a simple example that uses the Event module and loads 70This is a simple example that uses the EV module and loads
91F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
92 72
93 use Fcntl; 73 use Fcntl;
94 use Event; 74 use EV;
95 use IO::AIO; 75 use IO::AIO;
96 76
97 # register the IO::AIO callback with Event 77 # register the IO::AIO callback with EV
98 Event->io (fd => IO::AIO::poll_fileno, 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
99 poll => 'r',
100 cb => \&IO::AIO::poll_cb);
101 79
102 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
103 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
104 my $fh = shift 82 my $fh = shift
105 or die "error while opening: $!"; 83 or die "error while opening: $!";
106 84
107 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
108 my $size = -s $fh; 86 my $size = -s $fh;
117 95
118 # file contents now in $contents 96 # file contents now in $contents
119 print $contents; 97 print $contents;
120 98
121 # exit event loop and program 99 # exit event loop and program
122 Event::unloop; 100 EV::unloop;
123 }; 101 };
124 }; 102 };
125 103
126 # possibly queue up other requests, or open GUI windows, 104 # possibly queue up other requests, or open GUI windows,
127 # check for sockets etc. etc. 105 # check for sockets etc. etc.
128 106
129 # process events as long as there are some: 107 # process events as long as there are some:
130 Event::loop; 108 EV::loop;
131 109
132=head1 REQUEST ANATOMY AND LIFETIME 110=head1 REQUEST ANATOMY AND LIFETIME
133 111
134Every C<aio_*> function creates a request. which is a C data structure not 112Every C<aio_*> function creates a request. which is a C data structure not
135directly visible to Perl. 113directly visible to Perl.
183 161
184=cut 162=cut
185 163
186package IO::AIO; 164package IO::AIO;
187 165
188no warnings; 166use Carp ();
189use strict 'vars'; 167
168use common::sense;
190 169
191use base 'Exporter'; 170use base 'Exporter';
192 171
193BEGIN { 172BEGIN {
194 our $VERSION = '2.41'; 173 our $VERSION = '4.15';
195 174
196 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
197 aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
198 aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
179 aio_pathsync aio_readahead aio_fiemap
180 aio_rename aio_link aio_move aio_copy aio_group
199 aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
200 aio_chown aio_chmod aio_utime aio_truncate); 182 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs
185 aio_wd);
186
201 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
202 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
203 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
204 nreqs nready npending nthreads 190 nreqs nready npending nthreads
205 max_poll_time max_poll_reqs); 191 max_poll_time max_poll_reqs
192 sendfile fadvise madvise
193 mmap munmap munlock munlockall);
194
195 push @AIO_REQ, qw(aio_busy); # not exported
206 196
207 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
208 198
209 require XSLoader; 199 require XSLoader;
210 XSLoader::load ("IO::AIO", $VERSION); 200 XSLoader::load ("IO::AIO", $VERSION);
211} 201}
212 202
213=head1 FUNCTIONS 203=head1 FUNCTIONS
214 204
215=head2 AIO REQUEST FUNCTIONS 205=head2 QUICK OVERVIEW
206
207This section simply lists the prototypes of the most important functions
208for quick reference. See the following sections for function-by-function
209documentation.
210
211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status)
214 aio_seek $fh,$offset,$whence, $callback->($offs)
215 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
217 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
218 aio_readahead $fh,$offset,$length, $callback->($retval)
219 aio_stat $fh_or_path, $callback->($status)
220 aio_lstat $fh, $callback->($status)
221 aio_statvfs $fh_or_path, $callback->($statvfs)
222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
223 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_truncate $fh_or_path, $offset, $callback->($status)
226 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
227 aio_unlink $pathname, $callback->($status)
228 aio_mknod $pathname, $mode, $dev, $callback->($status)
229 aio_link $srcpath, $dstpath, $callback->($status)
230 aio_symlink $srcpath, $dstpath, $callback->($status)
231 aio_readlink $pathname, $callback->($link)
232 aio_realpath $pathname, $callback->($link)
233 aio_rename $srcpath, $dstpath, $callback->($status)
234 aio_mkdir $pathname, $mode, $callback->($status)
235 aio_rmdir $pathname, $callback->($status)
236 aio_readdir $pathname, $callback->($entries)
237 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
238 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
239 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
240 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
241 aio_load $pathname, $data, $callback->($status)
242 aio_copy $srcpath, $dstpath, $callback->($status)
243 aio_move $srcpath, $dstpath, $callback->($status)
244 aio_rmtree $pathname, $callback->($status)
245 aio_sync $callback->($status)
246 aio_syncfs $fh, $callback->($status)
247 aio_fsync $fh, $callback->($status)
248 aio_fdatasync $fh, $callback->($status)
249 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
250 aio_pathsync $pathname, $callback->($status)
251 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
252 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
253 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
254 aio_mlockall $flags, $callback->($status)
255 aio_group $callback->(...)
256 aio_nop $callback->()
257
258 $prev_pri = aioreq_pri [$pri]
259 aioreq_nice $pri_adjust
260
261 IO::AIO::poll_wait
262 IO::AIO::poll_cb
263 IO::AIO::poll
264 IO::AIO::flush
265 IO::AIO::max_poll_reqs $nreqs
266 IO::AIO::max_poll_time $seconds
267 IO::AIO::min_parallel $nthreads
268 IO::AIO::max_parallel $nthreads
269 IO::AIO::max_idle $nthreads
270 IO::AIO::idle_timeout $seconds
271 IO::AIO::max_outstanding $maxreqs
272 IO::AIO::nreqs
273 IO::AIO::nready
274 IO::AIO::npending
275
276 IO::AIO::sendfile $ofh, $ifh, $offset, $count
277 IO::AIO::fadvise $fh, $offset, $len, $advice
278 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
279 IO::AIO::munmap $scalar
280 IO::AIO::madvise $scalar, $offset, $length, $advice
281 IO::AIO::mprotect $scalar, $offset, $length, $protect
282 IO::AIO::munlock $scalar, $offset = 0, $length = undef
283 IO::AIO::munlockall
284
285=head2 API NOTES
216 286
217All the C<aio_*> calls are more or less thin wrappers around the syscall 287All the C<aio_*> calls are more or less thin wrappers around the syscall
218with the same name (sans C<aio_>). The arguments are similar or identical, 288with the same name (sans C<aio_>). The arguments are similar or identical,
219and they all accept an additional (and optional) C<$callback> argument 289and they all accept an additional (and optional) C<$callback> argument
220which must be a code reference. This code reference will get called with 290which must be a code reference. This code reference will be called after
221the syscall return code (e.g. most syscalls return C<-1> on error, unlike 291the syscall has been executed in an asynchronous fashion. The results
222perl, which usually delivers "false") as it's sole argument when the given 292of the request will be passed as arguments to the callback (and, if an
223syscall has been executed asynchronously. 293error occured, in C<$!>) - for most requests the syscall return code (e.g.
294most syscalls return C<-1> on error, unlike perl, which usually delivers
295"false").
296
297Some requests (such as C<aio_readdir>) pass the actual results and
298communicate failures by passing C<undef>.
224 299
225All functions expecting a filehandle keep a copy of the filehandle 300All functions expecting a filehandle keep a copy of the filehandle
226internally until the request has finished. 301internally until the request has finished.
227 302
228All functions return request objects of type L<IO::AIO::REQ> that allow 303All functions return request objects of type L<IO::AIO::REQ> that allow
229further manipulation of those requests while they are in-flight. 304further manipulation of those requests while they are in-flight.
230 305
231The pathnames you pass to these routines I<must> be absolute and 306The pathnames you pass to these routines I<should> be absolute. The
232encoded as octets. The reason for the former is that at the time the 307reason for this is that at the time the request is being executed, the
233request is being executed, the current working directory could have 308current working directory could have changed. Alternatively, you can
234changed. Alternatively, you can make sure that you never change the 309make sure that you never change the current working directory anywhere
235current working directory anywhere in the program and then use relative 310in the program and then use relative paths. You can also take advantage
236paths. 311of IO::AIOs working directory abstraction, that lets you specify paths
312relative to some previously-opened "working directory object" - see the
313description of the C<IO::AIO::WD> class later in this document.
237 314
238To encode pathnames as octets, either make sure you either: a) always pass 315To encode pathnames as octets, either make sure you either: a) always pass
239in filenames you got from outside (command line, readdir etc.) without 316in filenames you got from outside (command line, readdir etc.) without
240tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 317tinkering, b) are in your native filesystem encoding, c) use the Encode
241your pathnames to the locale (or other) encoding in effect in the user 318module and encode your pathnames to the locale (or other) encoding in
242environment, d) use Glib::filename_from_unicode on unicode filenames or e) 319effect in the user environment, d) use Glib::filename_from_unicode on
243use something else to ensure your scalar has the correct contents. 320unicode filenames or e) use something else to ensure your scalar has the
321correct contents.
244 322
245This works, btw. independent of the internal UTF-8 bit, which IO::AIO 323This works, btw. independent of the internal UTF-8 bit, which IO::AIO
246handles correctly wether it is set or not. 324handles correctly whether it is set or not.
325
326=head2 AIO REQUEST FUNCTIONS
247 327
248=over 4 328=over 4
249 329
250=item $prev_pri = aioreq_pri [$pri] 330=item $prev_pri = aioreq_pri [$pri]
251 331
298by the umask in effect then the request is being executed, so better never 378by the umask in effect then the request is being executed, so better never
299change the umask. 379change the umask.
300 380
301Example: 381Example:
302 382
303 aio_open "/etc/passwd", O_RDONLY, 0, sub { 383 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
304 if ($_[0]) { 384 if ($_[0]) {
305 print "open successful, fh is $_[0]\n"; 385 print "open successful, fh is $_[0]\n";
306 ... 386 ...
307 } else { 387 } else {
308 die "open failed: $!\n"; 388 die "open failed: $!\n";
309 } 389 }
310 }; 390 };
311 391
392In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
393C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
394following POSIX and non-POSIX constants are available (missing ones on
395your system are, as usual, C<0>):
396
397C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
398C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
399C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
400
312 401
313=item aio_close $fh, $callback->($status) 402=item aio_close $fh, $callback->($status)
314 403
315Asynchronously close a file and call the callback with the result 404Asynchronously close a file and call the callback with the result
316code. I<WARNING:> although accepted, you should not pass in a perl 405code.
317filehandle here, as perl will likely close the file descriptor another
318time when the filehandle is destroyed. Normally, you can safely call perls
319C<close> or just let filehandles go out of scope.
320 406
321This is supposed to be a bug in the API, so that might change. It's 407Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
322therefore best to avoid this function. 408closing the file descriptor associated with the filehandle itself.
323 409
410Therefore, C<aio_close> will not close the filehandle - instead it will
411use dup2 to overwrite the file descriptor with the write-end of a pipe
412(the pipe fd will be created on demand and will be cached).
413
414Or in other words: the file descriptor will be closed, but it will not be
415free for reuse until the perl filehandle is closed.
416
417=cut
418
419=item aio_seek $fh, $offset, $whence, $callback->($offs)
420
421Seeks the filehandle to the new C<$offset>, similarly to perl's
422C<sysseek>. The C<$whence> can use the traditional values (C<0> for
423C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
424C<IO::AIO::SEEK_END>).
425
426The resulting absolute offset will be passed to the callback, or C<-1> in
427case of an error.
428
429In theory, the C<$whence> constants could be different than the
430corresponding values from L<Fcntl>, but perl guarantees they are the same,
431so don't panic.
432
433As a GNU/Linux (and maybe Solaris) extension, also the constants
434C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
435could be found. No guarantees about suitability for use in C<aio_seek> or
436Perl's C<sysseek> can be made though, although I would naively assume they
437"just work".
324 438
325=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 439=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
326 440
327=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 441=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
328 442
329Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 443Reads or writes C<$length> bytes from or to the specified C<$fh> and
330into the scalar given by C<$data> and offset C<$dataoffset> and calls the 444C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
331callback without the actual number of bytes read (or -1 on error, just 445and calls the callback without the actual number of bytes read (or -1 on
332like the syscall). 446error, just like the syscall).
447
448C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
449offset plus the actual number of bytes read.
333 450
334If C<$offset> is undefined, then the current file descriptor offset will 451If C<$offset> is undefined, then the current file descriptor offset will
335be used (and updated), otherwise the file descriptor offset will not be 452be used (and updated), otherwise the file descriptor offset will not be
336changed by these calls. 453changed by these calls.
337 454
338If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 455If C<$length> is undefined in C<aio_write>, use the remaining length of
456C<$data>.
339 457
340If C<$dataoffset> is less than zero, it will be counted from the end of 458If C<$dataoffset> is less than zero, it will be counted from the end of
341C<$data>. 459C<$data>.
342 460
343The C<$data> scalar I<MUST NOT> be modified in any way while the request 461The C<$data> scalar I<MUST NOT> be modified in any way while the request
357 475
358Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 476Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
359reading at byte offset C<$in_offset>, and starts writing at the current 477reading at byte offset C<$in_offset>, and starts writing at the current
360file offset of C<$out_fh>. Because of that, it is not safe to issue more 478file offset of C<$out_fh>. Because of that, it is not safe to issue more
361than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 479than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
362other. 480other. The same C<$in_fh> works fine though, as this function does not
481move or use the file offset of C<$in_fh>.
363 482
483Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
484are written, and there is no way to find out how many more bytes have been
485read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
486number of bytes written to C<$out_fh>. Only if the result value equals
487C<$length> one can assume that C<$length> bytes have been read.
488
489Unlike with other C<aio_> functions, it makes a lot of sense to use
490C<aio_sendfile> on non-blocking sockets, as long as one end (typically
491the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
492the socket I/O will be non-blocking. Note, however, that you can run
493into a trap where C<aio_sendfile> reads some data with readahead, then
494fails to write all data, and when the socket is ready the next time, the
495data in the cache is already lost, forcing C<aio_sendfile> to again hit
496the disk. Explicit C<aio_read> + C<aio_write> let's you better control
497resource usage.
498
364This call tries to make use of a native C<sendfile> syscall to provide 499This call tries to make use of a native C<sendfile>-like syscall to
365zero-copy operation. For this to work, C<$out_fh> should refer to a 500provide zero-copy operation. For this to work, C<$out_fh> should refer to
366socket, and C<$in_fh> should refer to mmap'able file. 501a socket, and C<$in_fh> should refer to an mmap'able file.
367 502
368If the native sendfile call fails or is not implemented, it will be 503If a native sendfile cannot be found or it fails with C<ENOSYS>,
369emulated, so you can call C<aio_sendfile> on any type of filehandle 504C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
505C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
370regardless of the limitations of the operating system. 506type of filehandle regardless of the limitations of the operating system.
371 507
372Please note, however, that C<aio_sendfile> can read more bytes from 508As native sendfile syscalls (as practically any non-POSIX interface hacked
373C<$in_fh> than are written, and there is no way to find out how many 509together in a hurry to improve benchmark numbers) tend to be rather buggy
374bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 510on many systems, this implementation tries to work around some known bugs
375provides the number of bytes written to C<$out_fh>. Only if the result 511in Linux and FreeBSD kernels (probably others, too), but that might fail,
376value equals C<$length> one can assume that C<$length> bytes have been 512so you really really should check the return value of C<aio_sendfile> -
377read. 513fewre bytes than expected might have been transferred.
378 514
379 515
380=item aio_readahead $fh,$offset,$length, $callback->($retval) 516=item aio_readahead $fh,$offset,$length, $callback->($retval)
381 517
382C<aio_readahead> populates the page cache with data from a file so that 518C<aio_readahead> populates the page cache with data from a file so that
405 541
406Currently, the stats are always 64-bit-stats, i.e. instead of returning an 542Currently, the stats are always 64-bit-stats, i.e. instead of returning an
407error when stat'ing a large file, the results will be silently truncated 543error when stat'ing a large file, the results will be silently truncated
408unless perl itself is compiled with large file support. 544unless perl itself is compiled with large file support.
409 545
546To help interpret the mode and dev/rdev stat values, IO::AIO offers the
547following constants and functions (if not implemented, the constants will
548be C<0> and the functions will either C<croak> or fall back on traditional
549behaviour).
550
551C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
552C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
553C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
554
410Example: Print the length of F</etc/passwd>: 555Example: Print the length of F</etc/passwd>:
411 556
412 aio_stat "/etc/passwd", sub { 557 aio_stat "/etc/passwd", sub {
413 $_[0] and die "stat failed: $!"; 558 $_[0] and die "stat failed: $!";
414 print "size is ", -s _, "\n"; 559 print "size is ", -s _, "\n";
415 }; 560 };
416 561
417 562
563=item aio_statvfs $fh_or_path, $callback->($statvfs)
564
565Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
566whether a file handle or path was passed.
567
568On success, the callback is passed a hash reference with the following
569members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
570C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
571is passed.
572
573The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
574C<ST_NOSUID>.
575
576The following non-POSIX IO::AIO::ST_* flag masks are defined to
577their correct value when available, or to C<0> on systems that do
578not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
579C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
580C<ST_NODIRATIME> and C<ST_RELATIME>.
581
582Example: stat C</wd> and dump out the data if successful.
583
584 aio_statvfs "/wd", sub {
585 my $f = $_[0]
586 or die "statvfs: $!";
587
588 use Data::Dumper;
589 say Dumper $f;
590 };
591
592 # result:
593 {
594 bsize => 1024,
595 bfree => 4333064312,
596 blocks => 10253828096,
597 files => 2050765568,
598 flag => 4096,
599 favail => 2042092649,
600 bavail => 4333064312,
601 ffree => 2042092649,
602 namemax => 255,
603 frsize => 1024,
604 fsid => 1810
605 }
606
607
418=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 608=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
419 609
420Works like perl's C<utime> function (including the special case of $atime 610Works like perl's C<utime> function (including the special case of $atime
421and $mtime being undef). Fractional times are supported if the underlying 611and $mtime being undef). Fractional times are supported if the underlying
422syscalls support them. 612syscalls support them.
449=item aio_truncate $fh_or_path, $offset, $callback->($status) 639=item aio_truncate $fh_or_path, $offset, $callback->($status)
450 640
451Works like truncate(2) or ftruncate(2). 641Works like truncate(2) or ftruncate(2).
452 642
453 643
644=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
645
646Allocates or freed disk space according to the C<$mode> argument. See the
647linux C<fallocate> docuemntation for details.
648
649C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
650to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE |
651IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
652
653The file system block size used by C<fallocate> is presumably the
654C<f_bsize> returned by C<statvfs>.
655
656If C<fallocate> isn't available or cannot be emulated (currently no
657emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
658
659
454=item aio_chmod $fh_or_path, $mode, $callback->($status) 660=item aio_chmod $fh_or_path, $mode, $callback->($status)
455 661
456Works like perl's C<chmod> function. 662Works like perl's C<chmod> function.
457 663
458 664
460 666
461Asynchronously unlink (delete) a file and call the callback with the 667Asynchronously unlink (delete) a file and call the callback with the
462result code. 668result code.
463 669
464 670
465=item aio_mknod $path, $mode, $dev, $callback->($status) 671=item aio_mknod $pathname, $mode, $dev, $callback->($status)
466 672
467[EXPERIMENTAL] 673[EXPERIMENTAL]
468 674
469Asynchronously create a device node (or fifo). See mknod(2). 675Asynchronously create a device node (or fifo). See mknod(2).
470 676
471The only (POSIX-) portable way of calling this function is: 677The only (POSIX-) portable way of calling this function is:
472 678
473 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 679 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
474 680
681See C<aio_stat> for info about some potentially helpful extra constants
682and functions.
475 683
476=item aio_link $srcpath, $dstpath, $callback->($status) 684=item aio_link $srcpath, $dstpath, $callback->($status)
477 685
478Asynchronously create a new link to the existing object at C<$srcpath> at 686Asynchronously create a new link to the existing object at C<$srcpath> at
479the path C<$dstpath> and call the callback with the result code. 687the path C<$dstpath> and call the callback with the result code.
483 691
484Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 692Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
485the path C<$dstpath> and call the callback with the result code. 693the path C<$dstpath> and call the callback with the result code.
486 694
487 695
488=item aio_readlink $path, $callback->($link) 696=item aio_readlink $pathname, $callback->($link)
489 697
490Asynchronously read the symlink specified by C<$path> and pass it to 698Asynchronously read the symlink specified by C<$path> and pass it to
491the callback. If an error occurs, nothing or undef gets passed to the 699the callback. If an error occurs, nothing or undef gets passed to the
492callback. 700callback.
493 701
494 702
703=item aio_realpath $pathname, $callback->($path)
704
705Asynchronously make the path absolute and resolve any symlinks in
706C<$path>. The resulting path only consists of directories (Same as
707L<Cwd::realpath>).
708
709This request can be used to get the absolute path of the current working
710directory by passing it a path of F<.> (a single dot).
711
712
495=item aio_rename $srcpath, $dstpath, $callback->($status) 713=item aio_rename $srcpath, $dstpath, $callback->($status)
496 714
497Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 715Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
498rename(2) and call the callback with the result code. 716rename(2) and call the callback with the result code.
499 717
515 733
516Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 734Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
517directory (i.e. opendir + readdir + closedir). The entries will not be 735directory (i.e. opendir + readdir + closedir). The entries will not be
518sorted, and will B<NOT> include the C<.> and C<..> entries. 736sorted, and will B<NOT> include the C<.> and C<..> entries.
519 737
520The callback a single argument which is either C<undef> or an array-ref 738The callback is passed a single argument which is either C<undef> or an
521with the filenames. 739array-ref with the filenames.
522 740
523 741
742=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
743
744Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
745tune behaviour and output format. In case of an error, C<$entries> will be
746C<undef>.
747
748The flags are a combination of the following constants, ORed together (the
749flags will also be passed to the callback, possibly modified):
750
751=over 4
752
753=item IO::AIO::READDIR_DENTS
754
755When this flag is off, then the callback gets an arrayref consisting of
756names only (as with C<aio_readdir>), otherwise it gets an arrayref with
757C<[$name, $type, $inode]> arrayrefs, each describing a single directory
758entry in more detail.
759
760C<$name> is the name of the entry.
761
762C<$type> is one of the C<IO::AIO::DT_xxx> constants:
763
764C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
765C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
766C<IO::AIO::DT_WHT>.
767
768C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
769know, you have to run stat yourself. Also, for speed reasons, the C<$type>
770scalars are read-only: you can not modify them.
771
772C<$inode> is the inode number (which might not be exact on systems with 64
773bit inode numbers and 32 bit perls). This field has unspecified content on
774systems that do not deliver the inode information.
775
776=item IO::AIO::READDIR_DIRS_FIRST
777
778When this flag is set, then the names will be returned in an order where
779likely directories come first, in optimal stat order. This is useful when
780you need to quickly find directories, or you want to find all directories
781while avoiding to stat() each entry.
782
783If the system returns type information in readdir, then this is used
784to find directories directly. Otherwise, likely directories are names
785beginning with ".", or otherwise names with no dots, of which names with
786short names are tried first.
787
788=item IO::AIO::READDIR_STAT_ORDER
789
790When this flag is set, then the names will be returned in an order
791suitable for stat()'ing each one. That is, when you plan to stat()
792all files in the given directory, then the returned order will likely
793be fastest.
794
795If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
796the likely dirs come first, resulting in a less optimal stat order.
797
798=item IO::AIO::READDIR_FOUND_UNKNOWN
799
800This flag should not be set when calling C<aio_readdirx>. Instead, it
801is being set by C<aio_readdirx>, when any of the C<$type>'s found were
802C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
803C<$type>'s are known, which can be used to speed up some algorithms.
804
805=back
806
807
524=item aio_load $path, $data, $callback->($status) 808=item aio_load $pathname, $data, $callback->($status)
525 809
526This is a composite request that tries to fully load the given file into 810This is a composite request that tries to fully load the given file into
527memory. Status is the same as with aio_read. 811memory. Status is the same as with aio_read.
528 812
529=cut 813=cut
530 814
531sub aio_load($$;$) { 815sub aio_load($$;$) {
532 aio_block {
533 my ($path, undef, $cb) = @_; 816 my ($path, undef, $cb) = @_;
534 my $data = \$_[1]; 817 my $data = \$_[1];
535 818
536 my $pri = aioreq_pri; 819 my $pri = aioreq_pri;
537 my $grp = aio_group $cb; 820 my $grp = aio_group $cb;
821
822 aioreq_pri $pri;
823 add $grp aio_open $path, O_RDONLY, 0, sub {
824 my $fh = shift
825 or return $grp->result (-1);
538 826
539 aioreq_pri $pri; 827 aioreq_pri $pri;
540 add $grp aio_open $path, O_RDONLY, 0, sub {
541 my $fh = shift
542 or return $grp->result (-1);
543
544 aioreq_pri $pri;
545 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { 828 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
546 $grp->result ($_[0]); 829 $grp->result ($_[0]);
547 };
548 }; 830 };
549
550 $grp
551 } 831 };
832
833 $grp
552} 834}
553 835
554=item aio_copy $srcpath, $dstpath, $callback->($status) 836=item aio_copy $srcpath, $dstpath, $callback->($status)
555 837
556Try to copy the I<file> (directories not supported as either source or 838Try to copy the I<file> (directories not supported as either source or
557destination) from C<$srcpath> to C<$dstpath> and call the callback with 839destination) from C<$srcpath> to C<$dstpath> and call the callback with
558the C<0> (error) or C<-1> ok. 840a status of C<0> (ok) or C<-1> (error, see C<$!>).
559 841
560This is a composite request that it creates the destination file with 842This is a composite request that creates the destination file with
561mode 0200 and copies the contents of the source file into it using 843mode 0200 and copies the contents of the source file into it using
562C<aio_sendfile>, followed by restoring atime, mtime, access mode and 844C<aio_sendfile>, followed by restoring atime, mtime, access mode and
563uid/gid, in that order. 845uid/gid, in that order.
564 846
565If an error occurs, the partial destination file will be unlinked, if 847If an error occurs, the partial destination file will be unlinked, if
567errors are being ignored. 849errors are being ignored.
568 850
569=cut 851=cut
570 852
571sub aio_copy($$;$) { 853sub aio_copy($$;$) {
572 aio_block {
573 my ($src, $dst, $cb) = @_; 854 my ($src, $dst, $cb) = @_;
574 855
575 my $pri = aioreq_pri; 856 my $pri = aioreq_pri;
576 my $grp = aio_group $cb; 857 my $grp = aio_group $cb;
577 858
578 aioreq_pri $pri; 859 aioreq_pri $pri;
579 add $grp aio_open $src, O_RDONLY, 0, sub { 860 add $grp aio_open $src, O_RDONLY, 0, sub {
580 if (my $src_fh = $_[0]) { 861 if (my $src_fh = $_[0]) {
581 my @stat = stat $src_fh; 862 my @stat = stat $src_fh; # hmm, might block over nfs?
582 863
583 aioreq_pri $pri; 864 aioreq_pri $pri;
584 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 865 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
585 if (my $dst_fh = $_[0]) { 866 if (my $dst_fh = $_[0]) {
586 aioreq_pri $pri; 867 aioreq_pri $pri;
587 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 868 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
588 if ($_[0] == $stat[7]) { 869 if ($_[0] == $stat[7]) {
589 $grp->result (0); 870 $grp->result (0);
590 close $src_fh; 871 close $src_fh;
591 872
592 # those should not normally block. should. should.
593 utime $stat[8], $stat[9], $dst;
594 chmod $stat[2] & 07777, $dst_fh;
595 chown $stat[4], $stat[5], $dst_fh;
596 close $dst_fh;
597 } else { 873 my $ch = sub {
598 $grp->result (-1);
599 close $src_fh;
600 close $dst_fh;
601
602 aioreq $pri; 874 aioreq_pri $pri;
875 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
876 aioreq_pri $pri;
877 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
878 aioreq_pri $pri;
603 add $grp aio_unlink $dst; 879 add $grp aio_close $dst_fh;
880 }
881 };
604 } 882 };
883
884 aioreq_pri $pri;
885 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
886 if ($_[0] < 0 && $! == ENOSYS) {
887 aioreq_pri $pri;
888 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
889 } else {
890 $ch->();
891 }
892 };
893 } else {
894 $grp->result (-1);
895 close $src_fh;
896 close $dst_fh;
897
898 aioreq $pri;
899 add $grp aio_unlink $dst;
605 }; 900 }
606 } else {
607 $grp->result (-1);
608 } 901 };
902 } else {
903 $grp->result (-1);
609 }, 904 }
610
611 } else {
612 $grp->result (-1);
613 } 905 },
906
907 } else {
908 $grp->result (-1);
614 }; 909 }
615
616 $grp
617 } 910 };
911
912 $grp
618} 913}
619 914
620=item aio_move $srcpath, $dstpath, $callback->($status) 915=item aio_move $srcpath, $dstpath, $callback->($status)
621 916
622Try to move the I<file> (directories not supported as either source or 917Try to move the I<file> (directories not supported as either source or
623destination) from C<$srcpath> to C<$dstpath> and call the callback with 918destination) from C<$srcpath> to C<$dstpath> and call the callback with
624the C<0> (error) or C<-1> ok. 919a status of C<0> (ok) or C<-1> (error, see C<$!>).
625 920
626This is a composite request that tries to rename(2) the file first. If 921This is a composite request that tries to rename(2) the file first; if
627rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 922rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
628that is successful, unlinking the C<$srcpath>. 923that is successful, unlinks the C<$srcpath>.
629 924
630=cut 925=cut
631 926
632sub aio_move($$;$) { 927sub aio_move($$;$) {
633 aio_block {
634 my ($src, $dst, $cb) = @_; 928 my ($src, $dst, $cb) = @_;
635 929
636 my $pri = aioreq_pri; 930 my $pri = aioreq_pri;
637 my $grp = aio_group $cb; 931 my $grp = aio_group $cb;
638 932
639 aioreq_pri $pri; 933 aioreq_pri $pri;
640 add $grp aio_rename $src, $dst, sub { 934 add $grp aio_rename $src, $dst, sub {
641 if ($_[0] && $! == EXDEV) { 935 if ($_[0] && $! == EXDEV) {
642 aioreq_pri $pri; 936 aioreq_pri $pri;
643 add $grp aio_copy $src, $dst, sub { 937 add $grp aio_copy $src, $dst, sub {
644 $grp->result ($_[0]);
645
646 if (!$_[0]) {
647 aioreq_pri $pri;
648 add $grp aio_unlink $src;
649 }
650 };
651 } else {
652 $grp->result ($_[0]); 938 $grp->result ($_[0]);
939
940 unless ($_[0]) {
941 aioreq_pri $pri;
942 add $grp aio_unlink $src;
943 }
653 } 944 };
945 } else {
946 $grp->result ($_[0]);
654 }; 947 }
655
656 $grp
657 } 948 };
949
950 $grp
658} 951}
659 952
660=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 953=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
661 954
662Scans a directory (similar to C<aio_readdir>) but additionally tries to 955Scans a directory (similar to C<aio_readdir>) but additionally tries to
663efficiently separate the entries of directory C<$path> into two sets of 956efficiently separate the entries of directory C<$path> into two sets of
664names, directories you can recurse into (directories), and ones you cannot 957names, directories you can recurse into (directories), and ones you cannot
665recurse into (everything else, including symlinks to directories). 958recurse into (everything else, including symlinks to directories).
682 975
683Implementation notes. 976Implementation notes.
684 977
685The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 978The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
686 979
980If readdir returns file type information, then this is used directly to
981find directories.
982
687After reading the directory, the modification time, size etc. of the 983Otherwise, after reading the directory, the modification time, size etc.
688directory before and after the readdir is checked, and if they match (and 984of the directory before and after the readdir is checked, and if they
689isn't the current time), the link count will be used to decide how many 985match (and isn't the current time), the link count will be used to decide
690entries are directories (if >= 2). Otherwise, no knowledge of the number 986how many entries are directories (if >= 2). Otherwise, no knowledge of the
691of subdirectories will be assumed. 987number of subdirectories will be assumed.
692 988
693Then entries will be sorted into likely directories (everything without 989Then entries will be sorted into likely directories a non-initial dot
694a non-initial dot currently) and likely non-directories (everything 990currently) and likely non-directories (see C<aio_readdirx>). Then every
695else). Then every entry plus an appended C</.> will be C<stat>'ed, 991entry plus an appended C</.> will be C<stat>'ed, likely directories first,
696likely directories first. If that succeeds, it assumes that the entry 992in order of their inode numbers. If that succeeds, it assumes that the
697is a directory or a symlink to directory (which will be checked 993entry is a directory or a symlink to directory (which will be checked
698seperately). This is often faster than stat'ing the entry itself because 994separately). This is often faster than stat'ing the entry itself because
699filesystems might detect the type of the entry without reading the inode 995filesystems might detect the type of the entry without reading the inode
700data (e.g. ext2fs filetype feature). 996data (e.g. ext2fs filetype feature), even on systems that cannot return
997the filetype information on readdir.
701 998
702If the known number of directories (link count - 2) has been reached, the 999If the known number of directories (link count - 2) has been reached, the
703rest of the entries is assumed to be non-directories. 1000rest of the entries is assumed to be non-directories.
704 1001
705This only works with certainty on POSIX (= UNIX) filesystems, which 1002This only works with certainty on POSIX (= UNIX) filesystems, which
710directory counting heuristic. 1007directory counting heuristic.
711 1008
712=cut 1009=cut
713 1010
714sub aio_scandir($$;$) { 1011sub aio_scandir($$;$) {
715 aio_block {
716 my ($path, $maxreq, $cb) = @_; 1012 my ($path, $maxreq, $cb) = @_;
717 1013
718 my $pri = aioreq_pri; 1014 my $pri = aioreq_pri;
719 1015
720 my $grp = aio_group $cb; 1016 my $grp = aio_group $cb;
721 1017
722 $maxreq = 4 if $maxreq <= 0; 1018 $maxreq = 4 if $maxreq <= 0;
1019
1020 # get a wd object
1021 aioreq_pri $pri;
1022 add $grp aio_wd $path, sub {
1023 $_[0]
1024 or return $grp->result ();
1025
1026 my $wd = [shift, "."];
723 1027
724 # stat once 1028 # stat once
725 aioreq_pri $pri; 1029 aioreq_pri $pri;
726 add $grp aio_stat $path, sub { 1030 add $grp aio_stat $wd, sub {
727 return $grp->result () if $_[0]; 1031 return $grp->result () if $_[0];
728 my $now = time; 1032 my $now = time;
729 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1033 my $hash1 = join ":", (stat _)[0,1,3,7,9];
730 1034
731 # read the directory entries 1035 # read the directory entries
732 aioreq_pri $pri; 1036 aioreq_pri $pri;
733 add $grp aio_readdir $path, sub { 1037 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
734 my $entries = shift 1038 my $entries = shift
735 or return $grp->result (); 1039 or return $grp->result ();
736 1040
737 # stat the dir another time 1041 # stat the dir another time
738 aioreq_pri $pri; 1042 aioreq_pri $pri;
739 add $grp aio_stat $path, sub { 1043 add $grp aio_stat $wd, sub {
740 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1044 my $hash2 = join ":", (stat _)[0,1,3,7,9];
741 1045
742 my $ndirs; 1046 my $ndirs;
743 1047
744 # take the slow route if anything looks fishy 1048 # take the slow route if anything looks fishy
745 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1049 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
746 $ndirs = -1; 1050 $ndirs = -1;
747 } else { 1051 } else {
748 # if nlink == 2, we are finished 1052 # if nlink == 2, we are finished
749 # on non-posix-fs's, we rely on nlink < 2 1053 # for non-posix-fs's, we rely on nlink < 2
750 $ndirs = (stat _)[3] - 2 1054 $ndirs = (stat _)[3] - 2
751 or return $grp->result ([], $entries); 1055 or return $grp->result ([], $entries);
752 } 1056 }
753 1057
754 # sort into likely dirs and likely nondirs
755 # dirs == files without ".", short entries first
756 $entries = [map $_->[0],
757 sort { $b->[1] cmp $a->[1] }
758 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
759 @$entries];
760
761 my (@dirs, @nondirs); 1058 my (@dirs, @nondirs);
762 1059
763 my $statgrp = add $grp aio_group sub { 1060 my $statgrp = add $grp aio_group sub {
764 $grp->result (\@dirs, \@nondirs); 1061 $grp->result (\@dirs, \@nondirs);
765 }; 1062 };
766 1063
767 limit $statgrp $maxreq; 1064 limit $statgrp $maxreq;
768 feed $statgrp sub { 1065 feed $statgrp sub {
769 return unless @$entries; 1066 return unless @$entries;
770 my $entry = pop @$entries; 1067 my $entry = shift @$entries;
771 1068
772 aioreq_pri $pri; 1069 aioreq_pri $pri;
1070 $wd->[1] = "$entry/.";
773 add $statgrp aio_stat "$path/$entry/.", sub { 1071 add $statgrp aio_stat $wd, sub {
774 if ($_[0] < 0) { 1072 if ($_[0] < 0) {
775 push @nondirs, $entry; 1073 push @nondirs, $entry;
776 } else { 1074 } else {
777 # need to check for real directory 1075 # need to check for real directory
778 aioreq_pri $pri; 1076 aioreq_pri $pri;
1077 $wd->[1] = $entry;
779 add $statgrp aio_lstat "$path/$entry", sub { 1078 add $statgrp aio_lstat $wd, sub {
780 if (-d _) { 1079 if (-d _) {
781 push @dirs, $entry; 1080 push @dirs, $entry;
782 1081
783 unless (--$ndirs) { 1082 unless (--$ndirs) {
784 push @nondirs, @$entries; 1083 push @nondirs, @$entries;
792 }; 1091 };
793 }; 1092 };
794 }; 1093 };
795 }; 1094 };
796 }; 1095 };
797
798 $grp
799 } 1096 };
1097
1098 $grp
800} 1099}
801 1100
802=item aio_rmtree $path, $callback->($status) 1101=item aio_rmtree $pathname, $callback->($status)
803 1102
804Delete a directory tree starting (and including) C<$path>, return the 1103Delete a directory tree starting (and including) C<$path>, return the
805status of the final C<rmdir> only. This is a composite request that 1104status of the final C<rmdir> only. This is a composite request that
806uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1105uses C<aio_scandir> to recurse into and rmdir directories, and unlink
807everything else. 1106everything else.
808 1107
809=cut 1108=cut
810 1109
811sub aio_rmtree; 1110sub aio_rmtree;
812sub aio_rmtree($;$) { 1111sub aio_rmtree($;$) {
813 aio_block {
814 my ($path, $cb) = @_; 1112 my ($path, $cb) = @_;
815 1113
816 my $pri = aioreq_pri; 1114 my $pri = aioreq_pri;
817 my $grp = aio_group $cb; 1115 my $grp = aio_group $cb;
818 1116
819 aioreq_pri $pri; 1117 aioreq_pri $pri;
820 add $grp aio_scandir $path, 0, sub { 1118 add $grp aio_scandir $path, 0, sub {
821 my ($dirs, $nondirs) = @_; 1119 my ($dirs, $nondirs) = @_;
822 1120
823 my $dirgrp = aio_group sub { 1121 my $dirgrp = aio_group sub {
824 add $grp aio_rmdir $path, sub { 1122 add $grp aio_rmdir $path, sub {
825 $grp->result ($_[0]); 1123 $grp->result ($_[0]);
826 };
827 }; 1124 };
828
829 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
830 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
831
832 add $grp $dirgrp;
833 }; 1125 };
834 1126
835 $grp 1127 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
1128 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
1129
1130 add $grp $dirgrp;
836 } 1131 };
1132
1133 $grp
837} 1134}
1135
1136=item aio_sync $callback->($status)
1137
1138Asynchronously call sync and call the callback when finished.
838 1139
839=item aio_fsync $fh, $callback->($status) 1140=item aio_fsync $fh, $callback->($status)
840 1141
841Asynchronously call fsync on the given filehandle and call the callback 1142Asynchronously call fsync on the given filehandle and call the callback
842with the fsync result code. 1143with the fsync result code.
846Asynchronously call fdatasync on the given filehandle and call the 1147Asynchronously call fdatasync on the given filehandle and call the
847callback with the fdatasync result code. 1148callback with the fdatasync result code.
848 1149
849If this call isn't available because your OS lacks it or it couldn't be 1150If this call isn't available because your OS lacks it or it couldn't be
850detected, it will be emulated by calling C<fsync> instead. 1151detected, it will be emulated by calling C<fsync> instead.
1152
1153=item aio_syncfs $fh, $callback->($status)
1154
1155Asynchronously call the syncfs syscall to sync the filesystem associated
1156to the given filehandle and call the callback with the syncfs result
1157code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1158errno to C<ENOSYS> nevertheless.
1159
1160=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1161
1162Sync the data portion of the file specified by C<$offset> and C<$length>
1163to disk (but NOT the metadata), by calling the Linux-specific
1164sync_file_range call. If sync_file_range is not available or it returns
1165ENOSYS, then fdatasync or fsync is being substituted.
1166
1167C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1168C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1169C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1170manpage for details.
1171
1172=item aio_pathsync $pathname, $callback->($status)
1173
1174This request tries to open, fsync and close the given path. This is a
1175composite request intended to sync directories after directory operations
1176(E.g. rename). This might not work on all operating systems or have any
1177specific effect, but usually it makes sure that directory changes get
1178written to disc. It works for anything that can be opened for read-only,
1179not just directories.
1180
1181Future versions of this function might fall back to other methods when
1182C<fsync> on the directory fails (such as calling C<sync>).
1183
1184Passes C<0> when everything went ok, and C<-1> on error.
1185
1186=cut
1187
1188sub aio_pathsync($;$) {
1189 my ($path, $cb) = @_;
1190
1191 my $pri = aioreq_pri;
1192 my $grp = aio_group $cb;
1193
1194 aioreq_pri $pri;
1195 add $grp aio_open $path, O_RDONLY, 0, sub {
1196 my ($fh) = @_;
1197 if ($fh) {
1198 aioreq_pri $pri;
1199 add $grp aio_fsync $fh, sub {
1200 $grp->result ($_[0]);
1201
1202 aioreq_pri $pri;
1203 add $grp aio_close $fh;
1204 };
1205 } else {
1206 $grp->result (-1);
1207 }
1208 };
1209
1210 $grp
1211}
1212
1213=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1214
1215This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1216scalars (see the C<IO::AIO::mmap> function, although it also works on data
1217scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1218scalar must only be modified in-place while an aio operation is pending on
1219it).
1220
1221It calls the C<msync> function of your OS, if available, with the memory
1222area starting at C<$offset> in the string and ending C<$length> bytes
1223later. If C<$length> is negative, counts from the end, and if C<$length>
1224is C<undef>, then it goes till the end of the string. The flags can be
1225a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1226C<IO::AIO::MS_SYNC>.
1227
1228=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1229
1230This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1231scalars.
1232
1233It touches (reads or writes) all memory pages in the specified
1234range inside the scalar. All caveats and parameters are the same
1235as for C<aio_msync>, above, except for flags, which must be either
1236C<0> (which reads all pages and ensures they are instantiated) or
1237C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1238writing an octet from it, which dirties the page).
1239
1240=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1241
1242This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1243scalars.
1244
1245It reads in all the pages of the underlying storage into memory (if any)
1246and locks them, so they are not getting swapped/paged out or removed.
1247
1248If C<$length> is undefined, then the scalar will be locked till the end.
1249
1250On systems that do not implement C<mlock>, this function returns C<-1>
1251and sets errno to C<ENOSYS>.
1252
1253Note that the corresponding C<munlock> is synchronous and is
1254documented under L<MISCELLANEOUS FUNCTIONS>.
1255
1256Example: open a file, mmap and mlock it - both will be undone when
1257C<$data> gets destroyed.
1258
1259 open my $fh, "<", $path or die "$path: $!";
1260 my $data;
1261 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1262 aio_mlock $data; # mlock in background
1263
1264=item aio_mlockall $flags, $callback->($status)
1265
1266Calls the C<mlockall> function with the given C<$flags> (a combination of
1267C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1268
1269On systems that do not implement C<mlockall>, this function returns C<-1>
1270and sets errno to C<ENOSYS>.
1271
1272Note that the corresponding C<munlockall> is synchronous and is
1273documented under L<MISCELLANEOUS FUNCTIONS>.
1274
1275Example: asynchronously lock all current and future pages into memory.
1276
1277 aio_mlockall IO::AIO::MCL_FUTURE;
1278
1279=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1280
1281Queries the extents of the given file (by calling the Linux FIEMAP ioctl,
1282see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the
1283C<ioctl> is not available on your OS, then this rquiest will fail with
1284C<ENOSYS>.
1285
1286C<$start> is the starting offset to query extents for, C<$length> is the
1287size of the range to query - if it is C<undef>, then the whole file will
1288be queried.
1289
1290C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1291C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1292exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1293the data portion.
1294
1295C<$count> is the maximum number of extent records to return. If it is
1296C<undef>, then IO::AIO queries all extents of the file. As a very special
1297case, if it is C<0>, then the callback receives the number of extents
1298instead of the extents themselves.
1299
1300If an error occurs, the callback receives no arguments. The special
1301C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1302
1303Otherwise, the callback receives an array reference with extent
1304structures. Each extent structure is an array reference itself, with the
1305following members:
1306
1307 [$logical, $physical, $length, $flags]
1308
1309Flags is any combination of the following flag values (typically either C<0>
1310or C<IO::AIO::FIEMAP_EXTENT_LAST>):
1311
1312C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1313C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1314C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1315C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1316C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1317C<IO::AIO::FIEMAP_EXTENT_SHARED>.
851 1318
852=item aio_group $callback->(...) 1319=item aio_group $callback->(...)
853 1320
854This is a very special aio request: Instead of doing something, it is a 1321This is a very special aio request: Instead of doing something, it is a
855container for other aio requests, which is useful if you want to bundle 1322container for other aio requests, which is useful if you want to bundle
893immense (it blocks a thread for a long time) so do not use this function 1360immense (it blocks a thread for a long time) so do not use this function
894except to put your application under artificial I/O pressure. 1361except to put your application under artificial I/O pressure.
895 1362
896=back 1363=back
897 1364
1365
1366=head2 IO::AIO::WD - multiple working directories
1367
1368Your process only has one current working directory, which is used by all
1369threads. This makes it hard to use relative paths (some other component
1370could call C<chdir> at any time, and it is hard to control when the path
1371will be used by IO::AIO).
1372
1373One solution for this is to always use absolute paths. This usually works,
1374but can be quite slow (the kernel has to walk the whole path on every
1375access), and can also be a hassle to implement.
1376
1377Newer POSIX systems have a number of functions (openat, fdopendir,
1378futimensat and so on) that make it possible to specify working directories
1379per operation.
1380
1381For portability, and because the clowns who "designed", or shall I write,
1382perpetrated this new interface were obviously half-drunk, this abstraction
1383cannot be perfect, though.
1384
1385IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1386object. This object stores the canonicalised, absolute version of the
1387path, and on systems that allow it, also a directory file descriptor.
1388
1389Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1390or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1391object and a pathname instead (or the IO::AIO::WD object alone, which
1392gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1393IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1394to that IO::AIO::WD object.
1395
1396For example, to get a wd object for F</etc> and then stat F<passwd>
1397inside, you would write:
1398
1399 aio_wd "/etc", sub {
1400 my $etcdir = shift;
1401
1402 # although $etcdir can be undef on error, there is generally no reason
1403 # to check for errors here, as aio_stat will fail with ENOENT
1404 # when $etcdir is undef.
1405
1406 aio_stat [$etcdir, "passwd"], sub {
1407 # yay
1408 };
1409 };
1410
1411That C<aio_wd> is a request and not a normal function shows that creating
1412an IO::AIO::WD object is itself a potentially blocking operation, which is
1413why it is done asynchronously.
1414
1415To stat the directory obtained with C<aio_wd> above, one could write
1416either of the following three request calls:
1417
1418 aio_lstat "/etc" , sub { ... # pathname as normal string
1419 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1420 aio_lstat $wd , sub { ... # shorthand for the previous
1421
1422As with normal pathnames, IO::AIO keeps a copy of the working directory
1423object and the pathname string, so you could write the following without
1424causing any issues due to C<$path> getting reused:
1425
1426 my $path = [$wd, undef];
1427
1428 for my $name (qw(abc def ghi)) {
1429 $path->[1] = $name;
1430 aio_stat $path, sub {
1431 # ...
1432 };
1433 }
1434
1435There are some caveats: when directories get renamed (or deleted), the
1436pathname string doesn't change, so will point to the new directory (or
1437nowhere at all), while the directory fd, if available on the system,
1438will still point to the original directory. Most functions accepting a
1439pathname will use the directory fd on newer systems, and the string on
1440older systems. Some functions (such as realpath) will always rely on the
1441string form of the pathname.
1442
1443So this fucntionality is mainly useful to get some protection against
1444C<chdir>, to easily get an absolute path out of a relative path for future
1445reference, and to speed up doing many operations in the same directory
1446(e.g. when stat'ing all files in a directory).
1447
1448The following functions implement this working directory abstraction:
1449
1450=over 4
1451
1452=item aio_wd $pathname, $callback->($wd)
1453
1454Asynchonously canonicalise the given pathname and convert it to an
1455IO::AIO::WD object representing it. If possible and supported on the
1456system, also open a directory fd to speed up pathname resolution relative
1457to this working directory.
1458
1459If something goes wrong, then C<undef> is passwd to the callback instead
1460of a working directory object and C<$!> is set appropriately. Since
1461passing C<undef> as working directory component of a pathname fails the
1462request with C<ENOENT>, there is often no need for error checking in the
1463C<aio_wd> callback, as future requests using the value will fail in the
1464expected way.
1465
1466If this call isn't available because your OS lacks it or it couldn't be
1467detected, it will be emulated by calling C<fsync> instead.
1468
1469=item IO::AIO::CWD
1470
1471This is a compiletime constant (object) that represents the process
1472current working directory.
1473
1474Specifying this object as working directory object for a pathname is as
1475if the pathname would be specified directly, without a directory object,
1476e.g., these calls are functionally identical:
1477
1478 aio_stat "somefile", sub { ... };
1479 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1480
1481=back
1482
1483
898=head2 IO::AIO::REQ CLASS 1484=head2 IO::AIO::REQ CLASS
899 1485
900All non-aggregate C<aio_*> functions return an object of this class when 1486All non-aggregate C<aio_*> functions return an object of this class when
901called in non-void context. 1487called in non-void context.
902 1488
905=item cancel $req 1491=item cancel $req
906 1492
907Cancels the request, if possible. Has the effect of skipping execution 1493Cancels the request, if possible. Has the effect of skipping execution
908when entering the B<execute> state and skipping calling the callback when 1494when entering the B<execute> state and skipping calling the callback when
909entering the the B<result> state, but will leave the request otherwise 1495entering the the B<result> state, but will leave the request otherwise
910untouched. That means that requests that currently execute will not be 1496untouched (with the exception of readdir). That means that requests that
911stopped and resources held by the request will not be freed prematurely. 1497currently execute will not be stopped and resources held by the request
1498will not be freed prematurely.
912 1499
913=item cb $req $callback->(...) 1500=item cb $req $callback->(...)
914 1501
915Replace (or simply set) the callback registered to the request. 1502Replace (or simply set) the callback registered to the request.
916 1503
967Their lifetime, simplified, looks like this: when they are empty, they 1554Their lifetime, simplified, looks like this: when they are empty, they
968will finish very quickly. If they contain only requests that are in the 1555will finish very quickly. If they contain only requests that are in the
969C<done> state, they will also finish. Otherwise they will continue to 1556C<done> state, they will also finish. Otherwise they will continue to
970exist. 1557exist.
971 1558
972That means after creating a group you have some time to add requests. And 1559That means after creating a group you have some time to add requests
973in the callbacks of those requests, you can add further requests to the 1560(precisely before the callback has been invoked, which is only done within
974group. And only when all those requests have finished will the the group 1561the C<poll_cb>). And in the callbacks of those requests, you can add
975itself finish. 1562further requests to the group. And only when all those requests have
1563finished will the the group itself finish.
976 1564
977=over 4 1565=over 4
978 1566
979=item add $grp ... 1567=item add $grp ...
980 1568
989=item $grp->cancel_subs 1577=item $grp->cancel_subs
990 1578
991Cancel all subrequests and clears any feeder, but not the group request 1579Cancel all subrequests and clears any feeder, but not the group request
992itself. Useful when you queued a lot of events but got a result early. 1580itself. Useful when you queued a lot of events but got a result early.
993 1581
1582The group request will finish normally (you cannot add requests to the
1583group).
1584
994=item $grp->result (...) 1585=item $grp->result (...)
995 1586
996Set the result value(s) that will be passed to the group callback when all 1587Set the result value(s) that will be passed to the group callback when all
997subrequests have finished and set thre groups errno to the current value 1588subrequests have finished and set the groups errno to the current value
998of errno (just like calling C<errno> without an error number). By default, 1589of errno (just like calling C<errno> without an error number). By default,
999no argument will be passed and errno is zero. 1590no argument will be passed and errno is zero.
1000 1591
1001=item $grp->errno ([$errno]) 1592=item $grp->errno ([$errno])
1002 1593
1013=item feed $grp $callback->($grp) 1604=item feed $grp $callback->($grp)
1014 1605
1015Sets a feeder/generator on this group: every group can have an attached 1606Sets a feeder/generator on this group: every group can have an attached
1016generator that generates requests if idle. The idea behind this is that, 1607generator that generates requests if idle. The idea behind this is that,
1017although you could just queue as many requests as you want in a group, 1608although you could just queue as many requests as you want in a group,
1018this might starve other requests for a potentially long time. For 1609this might starve other requests for a potentially long time. For example,
1019example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1610C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1020requests, delaying any later requests for a long time. 1611requests, delaying any later requests for a long time.
1021 1612
1022To avoid this, and allow incremental generation of requests, you can 1613To avoid this, and allow incremental generation of requests, you can
1023instead a group and set a feeder on it that generates those requests. The 1614instead a group and set a feeder on it that generates those requests. The
1024feed callback will be called whenever there are few enough (see C<limit>, 1615feed callback will be called whenever there are few enough (see C<limit>,
1029not impose any limits). 1620not impose any limits).
1030 1621
1031If the feed does not queue more requests when called, it will be 1622If the feed does not queue more requests when called, it will be
1032automatically removed from the group. 1623automatically removed from the group.
1033 1624
1034If the feed limit is C<0>, it will be set to C<2> automatically. 1625If the feed limit is C<0> when this method is called, it will be set to
1626C<2> automatically.
1035 1627
1036Example: 1628Example:
1037 1629
1038 # stat all files in @files, but only ever use four aio requests concurrently: 1630 # stat all files in @files, but only ever use four aio requests concurrently:
1039 1631
1051Sets the feeder limit for the group: The feeder will be called whenever 1643Sets the feeder limit for the group: The feeder will be called whenever
1052the group contains less than this many requests. 1644the group contains less than this many requests.
1053 1645
1054Setting the limit to C<0> will pause the feeding process. 1646Setting the limit to C<0> will pause the feeding process.
1055 1647
1648The default value for the limit is C<0>, but note that setting a feeder
1649automatically bumps it up to C<2>.
1650
1056=back 1651=back
1057 1652
1058=head2 SUPPORT FUNCTIONS 1653=head2 SUPPORT FUNCTIONS
1059 1654
1060=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1655=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1062=over 4 1657=over 4
1063 1658
1064=item $fileno = IO::AIO::poll_fileno 1659=item $fileno = IO::AIO::poll_fileno
1065 1660
1066Return the I<request result pipe file descriptor>. This filehandle must be 1661Return the I<request result pipe file descriptor>. This filehandle must be
1067polled for reading by some mechanism outside this module (e.g. Event or 1662polled for reading by some mechanism outside this module (e.g. EV, Glib,
1068select, see below or the SYNOPSIS). If the pipe becomes readable you have 1663select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1069to call C<poll_cb> to check the results. 1664you have to call C<poll_cb> to check the results.
1070 1665
1071See C<poll_cb> for an example. 1666See C<poll_cb> for an example.
1072 1667
1073=item IO::AIO::poll_cb 1668=item IO::AIO::poll_cb
1074 1669
1075Process some outstanding events on the result pipe. You have to call this 1670Process some outstanding events on the result pipe. You have to call
1076regularly. Returns the number of events processed. Returns immediately 1671this regularly. Returns C<0> if all events could be processed (or there
1077when no events are outstanding. The amount of events processed depends on 1672were no events to process), or C<-1> if it returned earlier for whatever
1078the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1673reason. Returns immediately when no events are outstanding. The amount of
1674events processed depends on the settings of C<IO::AIO::max_poll_req> and
1675C<IO::AIO::max_poll_time>.
1079 1676
1080If not all requests were processed for whatever reason, the filehandle 1677If not all requests were processed for whatever reason, the filehandle
1081will still be ready when C<poll_cb> returns. 1678will still be ready when C<poll_cb> returns, so normally you don't have to
1679do anything special to have it called later.
1680
1681Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1682ready, it can be beneficial to call this function from loops which submit
1683a lot of requests, to make sure the results get processed when they become
1684available and not just when the loop is finished and the event loop takes
1685over again. This function returns very fast when there are no outstanding
1686requests.
1082 1687
1083Example: Install an Event watcher that automatically calls 1688Example: Install an Event watcher that automatically calls
1084IO::AIO::poll_cb with high priority: 1689IO::AIO::poll_cb with high priority (more examples can be found in the
1690SYNOPSIS section, at the top of this document):
1085 1691
1086 Event->io (fd => IO::AIO::poll_fileno, 1692 Event->io (fd => IO::AIO::poll_fileno,
1087 poll => 'r', async => 1, 1693 poll => 'r', async => 1,
1088 cb => \&IO::AIO::poll_cb); 1694 cb => \&IO::AIO::poll_cb);
1695
1696=item IO::AIO::poll_wait
1697
1698If there are any outstanding requests and none of them in the result
1699phase, wait till the result filehandle becomes ready for reading (simply
1700does a C<select> on the filehandle. This is useful if you want to
1701synchronously wait for some requests to finish).
1702
1703See C<nreqs> for an example.
1704
1705=item IO::AIO::poll
1706
1707Waits until some requests have been handled.
1708
1709Returns the number of requests processed, but is otherwise strictly
1710equivalent to:
1711
1712 IO::AIO::poll_wait, IO::AIO::poll_cb
1713
1714=item IO::AIO::flush
1715
1716Wait till all outstanding AIO requests have been handled.
1717
1718Strictly equivalent to:
1719
1720 IO::AIO::poll_wait, IO::AIO::poll_cb
1721 while IO::AIO::nreqs;
1089 1722
1090=item IO::AIO::max_poll_reqs $nreqs 1723=item IO::AIO::max_poll_reqs $nreqs
1091 1724
1092=item IO::AIO::max_poll_time $seconds 1725=item IO::AIO::max_poll_time $seconds
1093 1726
1118 # use a low priority so other tasks have priority 1751 # use a low priority so other tasks have priority
1119 Event->io (fd => IO::AIO::poll_fileno, 1752 Event->io (fd => IO::AIO::poll_fileno,
1120 poll => 'r', nice => 1, 1753 poll => 'r', nice => 1,
1121 cb => &IO::AIO::poll_cb); 1754 cb => &IO::AIO::poll_cb);
1122 1755
1123=item IO::AIO::poll_wait
1124
1125If there are any outstanding requests and none of them in the result
1126phase, wait till the result filehandle becomes ready for reading (simply
1127does a C<select> on the filehandle. This is useful if you want to
1128synchronously wait for some requests to finish).
1129
1130See C<nreqs> for an example.
1131
1132=item IO::AIO::poll
1133
1134Waits until some requests have been handled.
1135
1136Returns the number of requests processed, but is otherwise strictly
1137equivalent to:
1138
1139 IO::AIO::poll_wait, IO::AIO::poll_cb
1140
1141=item IO::AIO::flush
1142
1143Wait till all outstanding AIO requests have been handled.
1144
1145Strictly equivalent to:
1146
1147 IO::AIO::poll_wait, IO::AIO::poll_cb
1148 while IO::AIO::nreqs;
1149
1150=back 1756=back
1151 1757
1152=head3 CONTROLLING THE NUMBER OF THREADS 1758=head3 CONTROLLING THE NUMBER OF THREADS
1153 1759
1154=over 1760=over
1187 1793
1188Under normal circumstances you don't need to call this function. 1794Under normal circumstances you don't need to call this function.
1189 1795
1190=item IO::AIO::max_idle $nthreads 1796=item IO::AIO::max_idle $nthreads
1191 1797
1192Limit the number of threads (default: 4) that are allowed to idle (i.e., 1798Limit the number of threads (default: 4) that are allowed to idle
1193threads that did not get a request to process within 10 seconds). That 1799(i.e., threads that did not get a request to process within the idle
1194means if a thread becomes idle while C<$nthreads> other threads are also 1800timeout (default: 10 seconds). That means if a thread becomes idle while
1195idle, it will free its resources and exit. 1801C<$nthreads> other threads are also idle, it will free its resources and
1802exit.
1196 1803
1197This is useful when you allow a large number of threads (e.g. 100 or 1000) 1804This is useful when you allow a large number of threads (e.g. 100 or 1000)
1198to allow for extremely high load situations, but want to free resources 1805to allow for extremely high load situations, but want to free resources
1199under normal circumstances (1000 threads can easily consume 30MB of RAM). 1806under normal circumstances (1000 threads can easily consume 30MB of RAM).
1200 1807
1201The default is probably ok in most situations, especially if thread 1808The default is probably ok in most situations, especially if thread
1202creation is fast. If thread creation is very slow on your system you might 1809creation is fast. If thread creation is very slow on your system you might
1203want to use larger values. 1810want to use larger values.
1204 1811
1812=item IO::AIO::idle_timeout $seconds
1813
1814Sets the minimum idle timeout (default 10) after which worker threads are
1815allowed to exit. SEe C<IO::AIO::max_idle>.
1816
1205=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1817=item IO::AIO::max_outstanding $maxreqs
1818
1819Sets the maximum number of outstanding requests to C<$nreqs>. If
1820you do queue up more than this number of requests, the next call to
1821C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1822C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1823longer exceeded.
1824
1825In other words, this setting does not enforce a queue limit, but can be
1826used to make poll functions block if the limit is exceeded.
1206 1827
1207This is a very bad function to use in interactive programs because it 1828This is a very bad function to use in interactive programs because it
1208blocks, and a bad way to reduce concurrency because it is inexact: Better 1829blocks, and a bad way to reduce concurrency because it is inexact: Better
1209use an C<aio_group> together with a feed callback. 1830use an C<aio_group> together with a feed callback.
1210 1831
1211Sets the maximum number of outstanding requests to C<$nreqs>. If you 1832It's main use is in scripts without an event loop - when you want to stat
1212do queue up more than this number of requests, the next call to the 1833a lot of files, you can write somehting like this:
1213C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1214function will block until the limit is no longer exceeded.
1215 1834
1216The default value is very large, so there is no practical limit on the 1835 IO::AIO::max_outstanding 32;
1217number of outstanding requests.
1218 1836
1219You can still queue as many requests as you want. Therefore, 1837 for my $path (...) {
1220C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1838 aio_stat $path , ...;
1221as a stop gap to shield against fatal memory overflow (with large values). 1839 IO::AIO::poll_cb;
1840 }
1841
1842 IO::AIO::flush;
1843
1844The call to C<poll_cb> inside the loop will normally return instantly, but
1845as soon as more thna C<32> reqeusts are in-flight, it will block until
1846some requests have been handled. This keeps the loop from pushing a large
1847number of C<aio_stat> requests onto the queue.
1848
1849The default value for C<max_outstanding> is very large, so there is no
1850practical limit on the number of outstanding requests.
1222 1851
1223=back 1852=back
1224 1853
1225=head3 STATISTICAL INFORMATION 1854=head3 STATISTICAL INFORMATION
1226 1855
1246Returns the number of requests currently in the pending state (executed, 1875Returns the number of requests currently in the pending state (executed,
1247but not yet processed by poll_cb). 1876but not yet processed by poll_cb).
1248 1877
1249=back 1878=back
1250 1879
1880=head3 MISCELLANEOUS FUNCTIONS
1881
1882IO::AIO implements some functions that might be useful, but are not
1883asynchronous.
1884
1885=over 4
1886
1887=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1888
1889Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1890but is blocking (this makes most sense if you know the input data is
1891likely cached already and the output filehandle is set to non-blocking
1892operations).
1893
1894Returns the number of bytes copied, or C<-1> on error.
1895
1896=item IO::AIO::fadvise $fh, $offset, $len, $advice
1897
1898Simply calls the C<posix_fadvise> function (see its
1899manpage for details). The following advice constants are
1900available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1901C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1902C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1903
1904On systems that do not implement C<posix_fadvise>, this function returns
1905ENOSYS, otherwise the return value of C<posix_fadvise>.
1906
1907=item IO::AIO::madvise $scalar, $offset, $len, $advice
1908
1909Simply calls the C<posix_madvise> function (see its
1910manpage for details). The following advice constants are
1911available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1912C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1913
1914On systems that do not implement C<posix_madvise>, this function returns
1915ENOSYS, otherwise the return value of C<posix_madvise>.
1916
1917=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1918
1919Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1920$scalar (see its manpage for details). The following protect
1921constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1922C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1923
1924On systems that do not implement C<mprotect>, this function returns
1925ENOSYS, otherwise the return value of C<mprotect>.
1926
1927=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1928
1929Memory-maps a file (or anonymous memory range) and attaches it to the
1930given C<$scalar>, which will act like a string scalar. Returns true on
1931success, and false otherwise.
1932
1933The only operations allowed on the scalar are C<substr>/C<vec> that don't
1934change the string length, and most read-only operations such as copying it
1935or searching it with regexes and so on.
1936
1937Anything else is unsafe and will, at best, result in memory leaks.
1938
1939The memory map associated with the C<$scalar> is automatically removed
1940when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1941C<IO::AIO::munmap> functions are called.
1942
1943This calls the C<mmap>(2) function internally. See your system's manual
1944page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1945
1946The C<$length> must be larger than zero and smaller than the actual
1947filesize.
1948
1949C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1950C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1951
1952C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1953C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1954not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1955(which is set to C<MAP_ANON> if your system only provides this
1956constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1957C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1958C<IO::AIO::MAP_NONBLOCK>
1959
1960If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1961
1962C<$offset> is the offset from the start of the file - it generally must be
1963a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1964
1965Example:
1966
1967 use Digest::MD5;
1968 use IO::AIO;
1969
1970 open my $fh, "<verybigfile"
1971 or die "$!";
1972
1973 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1974 or die "verybigfile: $!";
1975
1976 my $fast_md5 = md5 $data;
1977
1978=item IO::AIO::munmap $scalar
1979
1980Removes a previous mmap and undefines the C<$scalar>.
1981
1982=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1983
1984Calls the C<munlock> function, undoing the effects of a previous
1985C<aio_mlock> call (see its description for details).
1986
1987=item IO::AIO::munlockall
1988
1989Calls the C<munlockall> function.
1990
1991On systems that do not implement C<munlockall>, this function returns
1992ENOSYS, otherwise the return value of C<munlockall>.
1993
1994=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1995
1996Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1997C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
1998should be the file offset.
1999
2000C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2001silently corrupt the data in this case.
2002
2003The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2004C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2005C<IO::AIO::SPLICE_F_GIFT>.
2006
2007See the C<splice(2)> manpage for details.
2008
2009=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2010
2011Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
2012description for C<IO::AIO::splice> above for details.
2013
2014=back
2015
1251=cut 2016=cut
1252 2017
1253# support function to convert a fd into a perl filehandle
1254sub _fd2fh {
1255 return undef if $_[0] < 0;
1256
1257 # try to generate nice filehandles
1258 my $sym = "IO::AIO::fd#$_[0]";
1259 local *$sym;
1260
1261 open *$sym, "+<&=$_[0]" # usually works under any unix
1262 or open *$sym, "<&=$_[0]" # cygwin needs this
1263 or open *$sym, ">&=$_[0]" # or this
1264 or return undef;
1265
1266 *$sym
1267}
1268
1269min_parallel 8; 2018min_parallel 8;
1270 2019
1271END { flush } 2020END { flush }
1272 2021
12731; 20221;
1274 2023
2024=head1 EVENT LOOP INTEGRATION
2025
2026It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
2027automatically into many event loops:
2028
2029 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
2030 use AnyEvent::AIO;
2031
2032You can also integrate IO::AIO manually into many event loops, here are
2033some examples of how to do this:
2034
2035 # EV integration
2036 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
2037
2038 # Event integration
2039 Event->io (fd => IO::AIO::poll_fileno,
2040 poll => 'r',
2041 cb => \&IO::AIO::poll_cb);
2042
2043 # Glib/Gtk2 integration
2044 add_watch Glib::IO IO::AIO::poll_fileno,
2045 in => sub { IO::AIO::poll_cb; 1 };
2046
2047 # Tk integration
2048 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
2049 readable => \&IO::AIO::poll_cb);
2050
2051 # Danga::Socket integration
2052 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
2053 \&IO::AIO::poll_cb);
2054
1275=head2 FORK BEHAVIOUR 2055=head2 FORK BEHAVIOUR
1276 2056
1277This module should do "the right thing" when the process using it forks: 2057Usage of pthreads in a program changes the semantics of fork
2058considerably. Specifically, only async-safe functions can be called after
2059fork. Perl doesn't know about this, so in general, you cannot call fork
2060with defined behaviour in perl if pthreads are involved. IO::AIO uses
2061pthreads, so this applies, but many other extensions and (for inexplicable
2062reasons) perl itself often is linked against pthreads, so this limitation
2063applies to quite a lot of perls.
1278 2064
1279Before the fork, IO::AIO enters a quiescent state where no requests 2065This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1280can be added in other threads and no results will be processed. After 2066only works in the process that loaded it. Forking is fully supported, but
1281the fork the parent simply leaves the quiescent state and continues 2067using IO::AIO in the child is not.
1282request/result processing, while the child frees the request/result queue
1283(so that the requests started before the fork will only be handled in the
1284parent). Threads will be started on demand until the limit set in the
1285parent process has been reached again.
1286 2068
1287In short: the parent will, after a short pause, continue as if fork had 2069You might get around by not I<using> IO::AIO before (or after)
1288not been called, while the child will act as if IO::AIO has not been used 2070forking. You could also try to call the L<IO::AIO::reinit> function in the
1289yet. 2071child:
2072
2073=over 4
2074
2075=item IO::AIO::reinit
2076
2077Abandons all current requests and I/O threads and simply reinitialises all
2078data structures. This is not an operation supported by any standards, but
2079happens to work on GNU/Linux and some newer BSD systems.
2080
2081The only reasonable use for this function is to call it after forking, if
2082C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
2083the process will result in undefined behaviour. Calling it at any time
2084will also result in any undefined (by POSIX) behaviour.
2085
2086=back
1290 2087
1291=head2 MEMORY USAGE 2088=head2 MEMORY USAGE
1292 2089
1293Per-request usage: 2090Per-request usage:
1294 2091
1311 2108
1312Known bugs will be fixed in the next release. 2109Known bugs will be fixed in the next release.
1313 2110
1314=head1 SEE ALSO 2111=head1 SEE ALSO
1315 2112
1316L<Coro::AIO>. 2113L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2114more natural syntax.
1317 2115
1318=head1 AUTHOR 2116=head1 AUTHOR
1319 2117
1320 Marc Lehmann <schmorp@schmorp.de> 2118 Marc Lehmann <schmorp@schmorp.de>
1321 http://home.schmorp.de/ 2119 http://home.schmorp.de/

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