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Revision 1.118 by root, Thu Nov 29 20:57:02 2007 UTC vs.
Revision 1.225 by root, Tue Apr 10 05:01:33 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 (EV, Event, Glib, Tk, urxvt, pureperl...)
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 # EV integration
36 my $w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
37
38 # Event integration
39 Event->io (fd => IO::AIO::poll_fileno,
40 poll => 'r',
41 cb => \&IO::AIO::poll_cb);
42
43 # Glib/Gtk2 integration
44 add_watch Glib::IO IO::AIO::poll_fileno,
45 in => sub { IO::AIO::poll_cb; 1 };
46
47 # Tk integration
48 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
49 readable => \&IO::AIO::poll_cb);
50
51 # Danga::Socket integration
52 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
53 \&IO::AIO::poll_cb);
54
55=head1 DESCRIPTION 31=head1 DESCRIPTION
56 32
57This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
58operating system supports. 34operating system supports. It is implemented as an interface to C<libeio>
35(L<http://software.schmorp.de/pkg/libeio.html>).
59 36
60Asynchronous means that operations that can normally block your program 37Asynchronous means that operations that can normally block your program
61(e.g. reading from disk) will be done asynchronously: the operation 38(e.g. reading from disk) will be done asynchronously: the operation
62will 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
63is extremely useful for programs that need to stay interactive even 40is extremely useful for programs that need to stay interactive even
67on 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
68concurrently. 45concurrently.
69 46
70While most of this works on all types of file descriptors (for 47While most of this works on all types of file descriptors (for
71example sockets), using these functions on file descriptors that 48example sockets), using these functions on file descriptors that
72support nonblocking operation (again, sockets, pipes etc.) is very 49support nonblocking operation (again, sockets, pipes etc.) is
73inefficient. 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>
74module): IO::AIO will naturally fit into such an event loop itself. 51module): IO::AIO will naturally fit into such an event loop itself.
75 52
76In this version, a number of threads are started that execute your 53In this version, a number of threads are started that execute your
77requests and signal their completion. You don't need thread support 54requests and signal their completion. You don't need thread support
78in 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
88yourself, 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
89call C<poll_cb> (or other C<aio_> functions) recursively. 66call C<poll_cb> (or other C<aio_> functions) recursively.
90 67
91=head2 EXAMPLE 68=head2 EXAMPLE
92 69
93This is a simple example that uses the Event module and loads 70This is a simple example that uses the EV module and loads
94F</etc/passwd> asynchronously: 71F</etc/passwd> asynchronously:
95 72
96 use Fcntl; 73 use Fcntl;
97 use Event; 74 use EV;
98 use IO::AIO; 75 use IO::AIO;
99 76
100 # register the IO::AIO callback with Event 77 # register the IO::AIO callback with EV
101 Event->io (fd => IO::AIO::poll_fileno, 78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
102 poll => 'r',
103 cb => \&IO::AIO::poll_cb);
104 79
105 # queue the request to open /etc/passwd 80 # queue the request to open /etc/passwd
106 aio_open "/etc/passwd", O_RDONLY, 0, sub { 81 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
107 my $fh = shift 82 my $fh = shift
108 or die "error while opening: $!"; 83 or die "error while opening: $!";
109 84
110 # stat'ing filehandles is generally non-blocking 85 # stat'ing filehandles is generally non-blocking
111 my $size = -s $fh; 86 my $size = -s $fh;
120 95
121 # file contents now in $contents 96 # file contents now in $contents
122 print $contents; 97 print $contents;
123 98
124 # exit event loop and program 99 # exit event loop and program
125 Event::unloop; 100 EV::unloop;
126 }; 101 };
127 }; 102 };
128 103
129 # possibly queue up other requests, or open GUI windows, 104 # possibly queue up other requests, or open GUI windows,
130 # check for sockets etc. etc. 105 # check for sockets etc. etc.
131 106
132 # process events as long as there are some: 107 # process events as long as there are some:
133 Event::loop; 108 EV::loop;
134 109
135=head1 REQUEST ANATOMY AND LIFETIME 110=head1 REQUEST ANATOMY AND LIFETIME
136 111
137Every 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
138directly visible to Perl. 113directly visible to Perl.
188 163
189package IO::AIO; 164package IO::AIO;
190 165
191use Carp (); 166use Carp ();
192 167
193no warnings; 168use common::sense;
194use strict 'vars';
195 169
196use base 'Exporter'; 170use base 'Exporter';
197 171
198BEGIN { 172BEGIN {
199 our $VERSION = '2.51'; 173 our $VERSION = '4.15';
200 174
201 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
202 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
203 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
204 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
205 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
206 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
207 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
208 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
209 nreqs nready npending nthreads 190 nreqs nready npending nthreads
210 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
211 196
212 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
213 198
214 require XSLoader; 199 require XSLoader;
215 XSLoader::load ("IO::AIO", $VERSION); 200 XSLoader::load ("IO::AIO", $VERSION);
216} 201}
217 202
218=head1 FUNCTIONS 203=head1 FUNCTIONS
219 204
220=head2 AIO REQUEST FUNCTIONS 205=head2 QUICK OVERVIEW
206
207This section simply lists the prototypes of the most important functions
208for quick reference. See the following sections for function-by-function
209documentation.
210
211 aio_wd $pathname, $callback->($wd)
212 aio_open $pathname, $flags, $mode, $callback->($fh)
213 aio_close $fh, $callback->($status)
214 aio_seek $fh,$offset,$whence, $callback->($offs)
215 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
216 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
217 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
218 aio_readahead $fh,$offset,$length, $callback->($retval)
219 aio_stat $fh_or_path, $callback->($status)
220 aio_lstat $fh, $callback->($status)
221 aio_statvfs $fh_or_path, $callback->($statvfs)
222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
223 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
225 aio_truncate $fh_or_path, $offset, $callback->($status)
226 aio_unlink $pathname, $callback->($status)
227 aio_mknod $pathname, $mode, $dev, $callback->($status)
228 aio_link $srcpath, $dstpath, $callback->($status)
229 aio_symlink $srcpath, $dstpath, $callback->($status)
230 aio_readlink $pathname, $callback->($link)
231 aio_realpath $pathname, $callback->($link)
232 aio_rename $srcpath, $dstpath, $callback->($status)
233 aio_mkdir $pathname, $mode, $callback->($status)
234 aio_rmdir $pathname, $callback->($status)
235 aio_readdir $pathname, $callback->($entries)
236 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
237 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
238 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
239 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
240 aio_load $pathname, $data, $callback->($status)
241 aio_copy $srcpath, $dstpath, $callback->($status)
242 aio_move $srcpath, $dstpath, $callback->($status)
243 aio_rmtree $pathname, $callback->($status)
244 aio_sync $callback->($status)
245 aio_syncfs $fh, $callback->($status)
246 aio_fsync $fh, $callback->($status)
247 aio_fdatasync $fh, $callback->($status)
248 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
249 aio_pathsync $pathname, $callback->($status)
250 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
251 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
252 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
253 aio_mlockall $flags, $callback->($status)
254 aio_group $callback->(...)
255 aio_nop $callback->()
256
257 $prev_pri = aioreq_pri [$pri]
258 aioreq_nice $pri_adjust
259
260 IO::AIO::poll_wait
261 IO::AIO::poll_cb
262 IO::AIO::poll
263 IO::AIO::flush
264 IO::AIO::max_poll_reqs $nreqs
265 IO::AIO::max_poll_time $seconds
266 IO::AIO::min_parallel $nthreads
267 IO::AIO::max_parallel $nthreads
268 IO::AIO::max_idle $nthreads
269 IO::AIO::idle_timeout $seconds
270 IO::AIO::max_outstanding $maxreqs
271 IO::AIO::nreqs
272 IO::AIO::nready
273 IO::AIO::npending
274
275 IO::AIO::sendfile $ofh, $ifh, $offset, $count
276 IO::AIO::fadvise $fh, $offset, $len, $advice
277 IO::AIO::madvise $scalar, $offset, $length, $advice
278 IO::AIO::mprotect $scalar, $offset, $length, $protect
279 IO::AIO::munlock $scalar, $offset = 0, $length = undef
280 IO::AIO::munlockall
281
282=head2 API NOTES
221 283
222All the C<aio_*> calls are more or less thin wrappers around the syscall 284All the C<aio_*> calls are more or less thin wrappers around the syscall
223with the same name (sans C<aio_>). The arguments are similar or identical, 285with the same name (sans C<aio_>). The arguments are similar or identical,
224and they all accept an additional (and optional) C<$callback> argument 286and they all accept an additional (and optional) C<$callback> argument
225which must be a code reference. This code reference will get called with 287which must be a code reference. This code reference will be called after
226the syscall return code (e.g. most syscalls return C<-1> on error, unlike 288the syscall has been executed in an asynchronous fashion. The results
227perl, which usually delivers "false") as it's sole argument when the given 289of the request will be passed as arguments to the callback (and, if an
228syscall has been executed asynchronously. 290error occured, in C<$!>) - for most requests the syscall return code (e.g.
291most syscalls return C<-1> on error, unlike perl, which usually delivers
292"false").
293
294Some requests (such as C<aio_readdir>) pass the actual results and
295communicate failures by passing C<undef>.
229 296
230All functions expecting a filehandle keep a copy of the filehandle 297All functions expecting a filehandle keep a copy of the filehandle
231internally until the request has finished. 298internally until the request has finished.
232 299
233All functions return request objects of type L<IO::AIO::REQ> that allow 300All functions return request objects of type L<IO::AIO::REQ> that allow
234further manipulation of those requests while they are in-flight. 301further manipulation of those requests while they are in-flight.
235 302
236The pathnames you pass to these routines I<must> be absolute and 303The pathnames you pass to these routines I<should> be absolute. The
237encoded as octets. The reason for the former is that at the time the 304reason for this is that at the time the request is being executed, the
238request is being executed, the current working directory could have 305current working directory could have changed. Alternatively, you can
239changed. Alternatively, you can make sure that you never change the 306make sure that you never change the current working directory anywhere
240current working directory anywhere in the program and then use relative 307in the program and then use relative paths. You can also take advantage
241paths. 308of IO::AIOs working directory abstraction, that lets you specify paths
309relative to some previously-opened "working directory object" - see the
310description of the C<IO::AIO::WD> class later in this document.
242 311
243To encode pathnames as octets, either make sure you either: a) always pass 312To encode pathnames as octets, either make sure you either: a) always pass
244in filenames you got from outside (command line, readdir etc.) without 313in filenames you got from outside (command line, readdir etc.) without
245tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 314tinkering, b) are in your native filesystem encoding, c) use the Encode
246your pathnames to the locale (or other) encoding in effect in the user 315module and encode your pathnames to the locale (or other) encoding in
247environment, d) use Glib::filename_from_unicode on unicode filenames or e) 316effect in the user environment, d) use Glib::filename_from_unicode on
248use something else to ensure your scalar has the correct contents. 317unicode filenames or e) use something else to ensure your scalar has the
318correct contents.
249 319
250This works, btw. independent of the internal UTF-8 bit, which IO::AIO 320This works, btw. independent of the internal UTF-8 bit, which IO::AIO
251handles correctly wether it is set or not. 321handles correctly whether it is set or not.
322
323=head2 AIO REQUEST FUNCTIONS
252 324
253=over 4 325=over 4
254 326
255=item $prev_pri = aioreq_pri [$pri] 327=item $prev_pri = aioreq_pri [$pri]
256 328
303by the umask in effect then the request is being executed, so better never 375by the umask in effect then the request is being executed, so better never
304change the umask. 376change the umask.
305 377
306Example: 378Example:
307 379
308 aio_open "/etc/passwd", O_RDONLY, 0, sub { 380 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
309 if ($_[0]) { 381 if ($_[0]) {
310 print "open successful, fh is $_[0]\n"; 382 print "open successful, fh is $_[0]\n";
311 ... 383 ...
312 } else { 384 } else {
313 die "open failed: $!\n"; 385 die "open failed: $!\n";
314 } 386 }
315 }; 387 };
316 388
389In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
390C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
391following POSIX and non-POSIX constants are available (missing ones on
392your system are, as usual, C<0>):
393
394C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
395C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
396C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
397
317 398
318=item aio_close $fh, $callback->($status) 399=item aio_close $fh, $callback->($status)
319 400
320Asynchronously close a file and call the callback with the result 401Asynchronously close a file and call the callback with the result
321code. 402code.
322 403
323Unfortunately, you can't do this to perl. Perl I<insists> very strongly on 404Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
324closing the file descriptor associated with the filehandle itself. Here is 405closing the file descriptor associated with the filehandle itself.
325what aio_close will try:
326 406
327 1. dup()licate the fd 407Therefore, C<aio_close> will not close the filehandle - instead it will
328 2. asynchronously close() the duplicated fd 408use dup2 to overwrite the file descriptor with the write-end of a pipe
329 3. dup()licate the fd once more 409(the pipe fd will be created on demand and will be cached).
330 4. let perl close() the filehandle
331 5. asynchronously close the duplicated fd
332 410
333The idea is that the first close() flushes stuff to disk that closing an 411Or in other words: the file descriptor will be closed, but it will not be
334fd will flush, so when perl closes the fd, nothing much will need to be 412free for reuse until the perl filehandle is closed.
335flushed. The second async. close() will then flush stuff to disk that
336closing the last fd to the file will flush.
337
338Just FYI, SuSv3 has this to say on close:
339
340 All outstanding record locks owned by the process on the file
341 associated with the file descriptor shall be removed.
342
343 If fildes refers to a socket, close() shall cause the socket to be
344 destroyed. ... close() shall block for up to the current linger
345 interval until all data is transmitted.
346 [this actually sounds like a specification bug, but who knows]
347
348And at least Linux additionally actually flushes stuff on every close,
349even when the file itself is still open.
350
351Sounds enourmously inefficient and complicated? Yes... please show me how
352to nuke perl's fd out of existence...
353 413
354=cut 414=cut
355 415
356sub aio_close($;$) { 416=item aio_seek $fh, $offset, $whence, $callback->($offs)
357 aio_block {
358 my ($fh, $cb) = @_;
359 417
360 my $pri = aioreq_pri; 418Seeks the filehandle to the new C<$offset>, similarly to perl's
361 my $grp = aio_group $cb; 419C<sysseek>. The C<$whence> can use the traditional values (C<0> for
420C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
421C<IO::AIO::SEEK_END>).
362 422
363 my $fd = fileno $fh; 423The resulting absolute offset will be passed to the callback, or C<-1> in
424case of an error.
364 425
365 defined $fd or Carp::croak "aio_close called with fd-less filehandle"; 426In theory, the C<$whence> constants could be different than the
427corresponding values from L<Fcntl>, but perl guarantees they are the same,
428so don't panic.
366 429
367 # if the dups fail we will simply get EBADF 430As a GNU/Linux (and maybe Solaris) extension, also the constants
368 my $fd2 = _dup $fd; 431C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
369 aioreq_pri $pri; 432could be found. No guarantees about suitability for use in C<aio_seek> or
370 add $grp _aio_close $fd2, sub { 433Perl's C<sysseek> can be made though, although I would naively assume they
371 my $fd2 = _dup $fd; 434"just work".
372 close $fh;
373 aioreq_pri $pri;
374 add $grp _aio_close $fd2, sub {
375 $grp->result ($_[0]);
376 };
377 };
378
379 $grp
380 }
381}
382
383 435
384=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 436=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
385 437
386=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 438=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
387 439
388Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 440Reads or writes C<$length> bytes from or to the specified C<$fh> and
389into the scalar given by C<$data> and offset C<$dataoffset> and calls the 441C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
390callback without the actual number of bytes read (or -1 on error, just 442and calls the callback without the actual number of bytes read (or -1 on
391like the syscall). 443error, just like the syscall).
444
445C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
446offset plus the actual number of bytes read.
392 447
393If C<$offset> is undefined, then the current file descriptor offset will 448If C<$offset> is undefined, then the current file descriptor offset will
394be used (and updated), otherwise the file descriptor offset will not be 449be used (and updated), otherwise the file descriptor offset will not be
395changed by these calls. 450changed by these calls.
396 451
397If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 452If C<$length> is undefined in C<aio_write>, use the remaining length of
453C<$data>.
398 454
399If C<$dataoffset> is less than zero, it will be counted from the end of 455If C<$dataoffset> is less than zero, it will be counted from the end of
400C<$data>. 456C<$data>.
401 457
402The C<$data> scalar I<MUST NOT> be modified in any way while the request 458The C<$data> scalar I<MUST NOT> be modified in any way while the request
416 472
417Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 473Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
418reading at byte offset C<$in_offset>, and starts writing at the current 474reading at byte offset C<$in_offset>, and starts writing at the current
419file offset of C<$out_fh>. Because of that, it is not safe to issue more 475file offset of C<$out_fh>. Because of that, it is not safe to issue more
420than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 476than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
421other. 477other. The same C<$in_fh> works fine though, as this function does not
478move or use the file offset of C<$in_fh>.
422 479
480Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
481are written, and there is no way to find out how many more bytes have been
482read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
483number of bytes written to C<$out_fh>. Only if the result value equals
484C<$length> one can assume that C<$length> bytes have been read.
485
486Unlike with other C<aio_> functions, it makes a lot of sense to use
487C<aio_sendfile> on non-blocking sockets, as long as one end (typically
488the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
489the socket I/O will be non-blocking. Note, however, that you can run
490into a trap where C<aio_sendfile> reads some data with readahead, then
491fails to write all data, and when the socket is ready the next time, the
492data in the cache is already lost, forcing C<aio_sendfile> to again hit
493the disk. Explicit C<aio_read> + C<aio_write> let's you better control
494resource usage.
495
423This call tries to make use of a native C<sendfile> syscall to provide 496This call tries to make use of a native C<sendfile>-like syscall to
424zero-copy operation. For this to work, C<$out_fh> should refer to a 497provide zero-copy operation. For this to work, C<$out_fh> should refer to
425socket, and C<$in_fh> should refer to mmap'able file. 498a socket, and C<$in_fh> should refer to an mmap'able file.
426 499
427If the native sendfile call fails or is not implemented, it will be 500If a native sendfile cannot be found or it fails with C<ENOSYS>,
428emulated, so you can call C<aio_sendfile> on any type of filehandle 501C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
502C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
429regardless of the limitations of the operating system. 503type of filehandle regardless of the limitations of the operating system.
430 504
431Please note, however, that C<aio_sendfile> can read more bytes from 505As native sendfile syscalls (as practically any non-POSIX interface hacked
432C<$in_fh> than are written, and there is no way to find out how many 506together in a hurry to improve benchmark numbers) tend to be rather buggy
433bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 507on many systems, this implementation tries to work around some known bugs
434provides the number of bytes written to C<$out_fh>. Only if the result 508in Linux and FreeBSD kernels (probably others, too), but that might fail,
435value equals C<$length> one can assume that C<$length> bytes have been 509so you really really should check the return value of C<aio_sendfile> -
436read. 510fewre bytes than expected might have been transferred.
437 511
438 512
439=item aio_readahead $fh,$offset,$length, $callback->($retval) 513=item aio_readahead $fh,$offset,$length, $callback->($retval)
440 514
441C<aio_readahead> populates the page cache with data from a file so that 515C<aio_readahead> populates the page cache with data from a file so that
464 538
465Currently, the stats are always 64-bit-stats, i.e. instead of returning an 539Currently, the stats are always 64-bit-stats, i.e. instead of returning an
466error when stat'ing a large file, the results will be silently truncated 540error when stat'ing a large file, the results will be silently truncated
467unless perl itself is compiled with large file support. 541unless perl itself is compiled with large file support.
468 542
543To help interpret the mode and dev/rdev stat values, IO::AIO offers the
544following constants and functions (if not implemented, the constants will
545be C<0> and the functions will either C<croak> or fall back on traditional
546behaviour).
547
548C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
549C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
550C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
551
469Example: Print the length of F</etc/passwd>: 552Example: Print the length of F</etc/passwd>:
470 553
471 aio_stat "/etc/passwd", sub { 554 aio_stat "/etc/passwd", sub {
472 $_[0] and die "stat failed: $!"; 555 $_[0] and die "stat failed: $!";
473 print "size is ", -s _, "\n"; 556 print "size is ", -s _, "\n";
474 }; 557 };
475 558
476 559
560=item aio_statvfs $fh_or_path, $callback->($statvfs)
561
562Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
563whether a file handle or path was passed.
564
565On success, the callback is passed a hash reference with the following
566members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
567C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
568is passed.
569
570The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
571C<ST_NOSUID>.
572
573The following non-POSIX IO::AIO::ST_* flag masks are defined to
574their correct value when available, or to C<0> on systems that do
575not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
576C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
577C<ST_NODIRATIME> and C<ST_RELATIME>.
578
579Example: stat C</wd> and dump out the data if successful.
580
581 aio_statvfs "/wd", sub {
582 my $f = $_[0]
583 or die "statvfs: $!";
584
585 use Data::Dumper;
586 say Dumper $f;
587 };
588
589 # result:
590 {
591 bsize => 1024,
592 bfree => 4333064312,
593 blocks => 10253828096,
594 files => 2050765568,
595 flag => 4096,
596 favail => 2042092649,
597 bavail => 4333064312,
598 ffree => 2042092649,
599 namemax => 255,
600 frsize => 1024,
601 fsid => 1810
602 }
603
604
477=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 605=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
478 606
479Works like perl's C<utime> function (including the special case of $atime 607Works like perl's C<utime> function (including the special case of $atime
480and $mtime being undef). Fractional times are supported if the underlying 608and $mtime being undef). Fractional times are supported if the underlying
481syscalls support them. 609syscalls support them.
519 647
520Asynchronously unlink (delete) a file and call the callback with the 648Asynchronously unlink (delete) a file and call the callback with the
521result code. 649result code.
522 650
523 651
524=item aio_mknod $path, $mode, $dev, $callback->($status) 652=item aio_mknod $pathname, $mode, $dev, $callback->($status)
525 653
526[EXPERIMENTAL] 654[EXPERIMENTAL]
527 655
528Asynchronously create a device node (or fifo). See mknod(2). 656Asynchronously create a device node (or fifo). See mknod(2).
529 657
530The only (POSIX-) portable way of calling this function is: 658The only (POSIX-) portable way of calling this function is:
531 659
532 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 660 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
533 661
662See C<aio_stat> for info about some potentially helpful extra constants
663and functions.
534 664
535=item aio_link $srcpath, $dstpath, $callback->($status) 665=item aio_link $srcpath, $dstpath, $callback->($status)
536 666
537Asynchronously create a new link to the existing object at C<$srcpath> at 667Asynchronously create a new link to the existing object at C<$srcpath> at
538the path C<$dstpath> and call the callback with the result code. 668the path C<$dstpath> and call the callback with the result code.
542 672
543Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 673Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
544the path C<$dstpath> and call the callback with the result code. 674the path C<$dstpath> and call the callback with the result code.
545 675
546 676
547=item aio_readlink $path, $callback->($link) 677=item aio_readlink $pathname, $callback->($link)
548 678
549Asynchronously read the symlink specified by C<$path> and pass it to 679Asynchronously read the symlink specified by C<$path> and pass it to
550the callback. If an error occurs, nothing or undef gets passed to the 680the callback. If an error occurs, nothing or undef gets passed to the
551callback. 681callback.
552 682
553 683
684=item aio_realpath $pathname, $callback->($path)
685
686Asynchronously make the path absolute and resolve any symlinks in
687C<$path>. The resulting path only consists of directories (Same as
688L<Cwd::realpath>).
689
690This request can be used to get the absolute path of the current working
691directory by passing it a path of F<.> (a single dot).
692
693
554=item aio_rename $srcpath, $dstpath, $callback->($status) 694=item aio_rename $srcpath, $dstpath, $callback->($status)
555 695
556Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 696Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
557rename(2) and call the callback with the result code. 697rename(2) and call the callback with the result code.
558 698
574 714
575Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 715Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
576directory (i.e. opendir + readdir + closedir). The entries will not be 716directory (i.e. opendir + readdir + closedir). The entries will not be
577sorted, and will B<NOT> include the C<.> and C<..> entries. 717sorted, and will B<NOT> include the C<.> and C<..> entries.
578 718
579The callback a single argument which is either C<undef> or an array-ref 719The callback is passed a single argument which is either C<undef> or an
580with the filenames. 720array-ref with the filenames.
581 721
582 722
723=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
724
725Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
726tune behaviour and output format. In case of an error, C<$entries> will be
727C<undef>.
728
729The flags are a combination of the following constants, ORed together (the
730flags will also be passed to the callback, possibly modified):
731
732=over 4
733
734=item IO::AIO::READDIR_DENTS
735
736When this flag is off, then the callback gets an arrayref consisting of
737names only (as with C<aio_readdir>), otherwise it gets an arrayref with
738C<[$name, $type, $inode]> arrayrefs, each describing a single directory
739entry in more detail.
740
741C<$name> is the name of the entry.
742
743C<$type> is one of the C<IO::AIO::DT_xxx> constants:
744
745C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
746C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
747C<IO::AIO::DT_WHT>.
748
749C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
750know, you have to run stat yourself. Also, for speed reasons, the C<$type>
751scalars are read-only: you can not modify them.
752
753C<$inode> is the inode number (which might not be exact on systems with 64
754bit inode numbers and 32 bit perls). This field has unspecified content on
755systems that do not deliver the inode information.
756
757=item IO::AIO::READDIR_DIRS_FIRST
758
759When this flag is set, then the names will be returned in an order where
760likely directories come first, in optimal stat order. This is useful when
761you need to quickly find directories, or you want to find all directories
762while avoiding to stat() each entry.
763
764If the system returns type information in readdir, then this is used
765to find directories directly. Otherwise, likely directories are names
766beginning with ".", or otherwise names with no dots, of which names with
767short names are tried first.
768
769=item IO::AIO::READDIR_STAT_ORDER
770
771When this flag is set, then the names will be returned in an order
772suitable for stat()'ing each one. That is, when you plan to stat()
773all files in the given directory, then the returned order will likely
774be fastest.
775
776If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
777the likely dirs come first, resulting in a less optimal stat order.
778
779=item IO::AIO::READDIR_FOUND_UNKNOWN
780
781This flag should not be set when calling C<aio_readdirx>. Instead, it
782is being set by C<aio_readdirx>, when any of the C<$type>'s found were
783C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
784C<$type>'s are known, which can be used to speed up some algorithms.
785
786=back
787
788
583=item aio_load $path, $data, $callback->($status) 789=item aio_load $pathname, $data, $callback->($status)
584 790
585This is a composite request that tries to fully load the given file into 791This is a composite request that tries to fully load the given file into
586memory. Status is the same as with aio_read. 792memory. Status is the same as with aio_read.
587 793
588=cut 794=cut
589 795
590sub aio_load($$;$) { 796sub aio_load($$;$) {
591 aio_block {
592 my ($path, undef, $cb) = @_; 797 my ($path, undef, $cb) = @_;
593 my $data = \$_[1]; 798 my $data = \$_[1];
594 799
595 my $pri = aioreq_pri; 800 my $pri = aioreq_pri;
596 my $grp = aio_group $cb; 801 my $grp = aio_group $cb;
802
803 aioreq_pri $pri;
804 add $grp aio_open $path, O_RDONLY, 0, sub {
805 my $fh = shift
806 or return $grp->result (-1);
597 807
598 aioreq_pri $pri; 808 aioreq_pri $pri;
599 add $grp aio_open $path, O_RDONLY, 0, sub {
600 my $fh = shift
601 or return $grp->result (-1);
602
603 aioreq_pri $pri;
604 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { 809 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
605 $grp->result ($_[0]); 810 $grp->result ($_[0]);
606 };
607 }; 811 };
608
609 $grp
610 } 812 };
813
814 $grp
611} 815}
612 816
613=item aio_copy $srcpath, $dstpath, $callback->($status) 817=item aio_copy $srcpath, $dstpath, $callback->($status)
614 818
615Try to copy the I<file> (directories not supported as either source or 819Try to copy the I<file> (directories not supported as either source or
616destination) from C<$srcpath> to C<$dstpath> and call the callback with 820destination) from C<$srcpath> to C<$dstpath> and call the callback with
617the C<0> (error) or C<-1> ok. 821a status of C<0> (ok) or C<-1> (error, see C<$!>).
618 822
619This is a composite request that it creates the destination file with 823This is a composite request that creates the destination file with
620mode 0200 and copies the contents of the source file into it using 824mode 0200 and copies the contents of the source file into it using
621C<aio_sendfile>, followed by restoring atime, mtime, access mode and 825C<aio_sendfile>, followed by restoring atime, mtime, access mode and
622uid/gid, in that order. 826uid/gid, in that order.
623 827
624If an error occurs, the partial destination file will be unlinked, if 828If an error occurs, the partial destination file will be unlinked, if
626errors are being ignored. 830errors are being ignored.
627 831
628=cut 832=cut
629 833
630sub aio_copy($$;$) { 834sub aio_copy($$;$) {
631 aio_block {
632 my ($src, $dst, $cb) = @_; 835 my ($src, $dst, $cb) = @_;
633 836
634 my $pri = aioreq_pri; 837 my $pri = aioreq_pri;
635 my $grp = aio_group $cb; 838 my $grp = aio_group $cb;
636 839
637 aioreq_pri $pri; 840 aioreq_pri $pri;
638 add $grp aio_open $src, O_RDONLY, 0, sub { 841 add $grp aio_open $src, O_RDONLY, 0, sub {
639 if (my $src_fh = $_[0]) { 842 if (my $src_fh = $_[0]) {
640 my @stat = stat $src_fh; 843 my @stat = stat $src_fh; # hmm, might block over nfs?
641 844
642 aioreq_pri $pri; 845 aioreq_pri $pri;
643 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 846 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
644 if (my $dst_fh = $_[0]) { 847 if (my $dst_fh = $_[0]) {
645 aioreq_pri $pri; 848 aioreq_pri $pri;
646 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 849 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
647 if ($_[0] == $stat[7]) { 850 if ($_[0] == $stat[7]) {
648 $grp->result (0); 851 $grp->result (0);
649 close $src_fh; 852 close $src_fh;
650 853
651 # those should not normally block. should. should.
652 utime $stat[8], $stat[9], $dst;
653 chmod $stat[2] & 07777, $dst_fh;
654 chown $stat[4], $stat[5], $dst_fh;
655 close $dst_fh;
656 } else { 854 my $ch = sub {
657 $grp->result (-1);
658 close $src_fh;
659 close $dst_fh;
660
661 aioreq $pri; 855 aioreq_pri $pri;
856 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
857 aioreq_pri $pri;
858 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
859 aioreq_pri $pri;
662 add $grp aio_unlink $dst; 860 add $grp aio_close $dst_fh;
861 }
862 };
663 } 863 };
864
865 aioreq_pri $pri;
866 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
867 if ($_[0] < 0 && $! == ENOSYS) {
868 aioreq_pri $pri;
869 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
870 } else {
871 $ch->();
872 }
873 };
874 } else {
875 $grp->result (-1);
876 close $src_fh;
877 close $dst_fh;
878
879 aioreq $pri;
880 add $grp aio_unlink $dst;
664 }; 881 }
665 } else {
666 $grp->result (-1);
667 } 882 };
883 } else {
884 $grp->result (-1);
668 }, 885 }
669
670 } else {
671 $grp->result (-1);
672 } 886 },
887
888 } else {
889 $grp->result (-1);
673 }; 890 }
674
675 $grp
676 } 891 };
892
893 $grp
677} 894}
678 895
679=item aio_move $srcpath, $dstpath, $callback->($status) 896=item aio_move $srcpath, $dstpath, $callback->($status)
680 897
681Try to move the I<file> (directories not supported as either source or 898Try to move the I<file> (directories not supported as either source or
682destination) from C<$srcpath> to C<$dstpath> and call the callback with 899destination) from C<$srcpath> to C<$dstpath> and call the callback with
683the C<0> (error) or C<-1> ok. 900a status of C<0> (ok) or C<-1> (error, see C<$!>).
684 901
685This is a composite request that tries to rename(2) the file first. If 902This is a composite request that tries to rename(2) the file first; if
686rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 903rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
687that is successful, unlinking the C<$srcpath>. 904that is successful, unlinks the C<$srcpath>.
688 905
689=cut 906=cut
690 907
691sub aio_move($$;$) { 908sub aio_move($$;$) {
692 aio_block {
693 my ($src, $dst, $cb) = @_; 909 my ($src, $dst, $cb) = @_;
694 910
695 my $pri = aioreq_pri; 911 my $pri = aioreq_pri;
696 my $grp = aio_group $cb; 912 my $grp = aio_group $cb;
697 913
698 aioreq_pri $pri; 914 aioreq_pri $pri;
699 add $grp aio_rename $src, $dst, sub { 915 add $grp aio_rename $src, $dst, sub {
700 if ($_[0] && $! == EXDEV) { 916 if ($_[0] && $! == EXDEV) {
701 aioreq_pri $pri; 917 aioreq_pri $pri;
702 add $grp aio_copy $src, $dst, sub { 918 add $grp aio_copy $src, $dst, sub {
703 $grp->result ($_[0]);
704
705 if (!$_[0]) {
706 aioreq_pri $pri;
707 add $grp aio_unlink $src;
708 }
709 };
710 } else {
711 $grp->result ($_[0]); 919 $grp->result ($_[0]);
920
921 unless ($_[0]) {
922 aioreq_pri $pri;
923 add $grp aio_unlink $src;
924 }
712 } 925 };
926 } else {
927 $grp->result ($_[0]);
713 }; 928 }
714
715 $grp
716 } 929 };
930
931 $grp
717} 932}
718 933
719=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 934=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
720 935
721Scans a directory (similar to C<aio_readdir>) but additionally tries to 936Scans a directory (similar to C<aio_readdir>) but additionally tries to
722efficiently separate the entries of directory C<$path> into two sets of 937efficiently separate the entries of directory C<$path> into two sets of
723names, directories you can recurse into (directories), and ones you cannot 938names, directories you can recurse into (directories), and ones you cannot
724recurse into (everything else, including symlinks to directories). 939recurse into (everything else, including symlinks to directories).
741 956
742Implementation notes. 957Implementation notes.
743 958
744The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 959The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
745 960
961If readdir returns file type information, then this is used directly to
962find directories.
963
746After reading the directory, the modification time, size etc. of the 964Otherwise, after reading the directory, the modification time, size etc.
747directory before and after the readdir is checked, and if they match (and 965of the directory before and after the readdir is checked, and if they
748isn't the current time), the link count will be used to decide how many 966match (and isn't the current time), the link count will be used to decide
749entries are directories (if >= 2). Otherwise, no knowledge of the number 967how many entries are directories (if >= 2). Otherwise, no knowledge of the
750of subdirectories will be assumed. 968number of subdirectories will be assumed.
751 969
752Then entries will be sorted into likely directories (everything without 970Then entries will be sorted into likely directories a non-initial dot
753a non-initial dot currently) and likely non-directories (everything 971currently) and likely non-directories (see C<aio_readdirx>). Then every
754else). Then every entry plus an appended C</.> will be C<stat>'ed, 972entry plus an appended C</.> will be C<stat>'ed, likely directories first,
755likely directories first. If that succeeds, it assumes that the entry 973in order of their inode numbers. If that succeeds, it assumes that the
756is a directory or a symlink to directory (which will be checked 974entry is a directory or a symlink to directory (which will be checked
757seperately). This is often faster than stat'ing the entry itself because 975separately). This is often faster than stat'ing the entry itself because
758filesystems might detect the type of the entry without reading the inode 976filesystems might detect the type of the entry without reading the inode
759data (e.g. ext2fs filetype feature). 977data (e.g. ext2fs filetype feature), even on systems that cannot return
978the filetype information on readdir.
760 979
761If the known number of directories (link count - 2) has been reached, the 980If the known number of directories (link count - 2) has been reached, the
762rest of the entries is assumed to be non-directories. 981rest of the entries is assumed to be non-directories.
763 982
764This only works with certainty on POSIX (= UNIX) filesystems, which 983This only works with certainty on POSIX (= UNIX) filesystems, which
769directory counting heuristic. 988directory counting heuristic.
770 989
771=cut 990=cut
772 991
773sub aio_scandir($$;$) { 992sub aio_scandir($$;$) {
774 aio_block {
775 my ($path, $maxreq, $cb) = @_; 993 my ($path, $maxreq, $cb) = @_;
776 994
777 my $pri = aioreq_pri; 995 my $pri = aioreq_pri;
778 996
779 my $grp = aio_group $cb; 997 my $grp = aio_group $cb;
780 998
781 $maxreq = 4 if $maxreq <= 0; 999 $maxreq = 4 if $maxreq <= 0;
1000
1001 # get a wd object
1002 aioreq_pri $pri;
1003 add $grp aio_wd $path, sub {
1004 $_[0]
1005 or return $grp->result ();
1006
1007 my $wd = [shift, "."];
782 1008
783 # stat once 1009 # stat once
784 aioreq_pri $pri; 1010 aioreq_pri $pri;
785 add $grp aio_stat $path, sub { 1011 add $grp aio_stat $wd, sub {
786 return $grp->result () if $_[0]; 1012 return $grp->result () if $_[0];
787 my $now = time; 1013 my $now = time;
788 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1014 my $hash1 = join ":", (stat _)[0,1,3,7,9];
789 1015
790 # read the directory entries 1016 # read the directory entries
791 aioreq_pri $pri; 1017 aioreq_pri $pri;
792 add $grp aio_readdir $path, sub { 1018 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
793 my $entries = shift 1019 my $entries = shift
794 or return $grp->result (); 1020 or return $grp->result ();
795 1021
796 # stat the dir another time 1022 # stat the dir another time
797 aioreq_pri $pri; 1023 aioreq_pri $pri;
798 add $grp aio_stat $path, sub { 1024 add $grp aio_stat $wd, sub {
799 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1025 my $hash2 = join ":", (stat _)[0,1,3,7,9];
800 1026
801 my $ndirs; 1027 my $ndirs;
802 1028
803 # take the slow route if anything looks fishy 1029 # take the slow route if anything looks fishy
804 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1030 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
805 $ndirs = -1; 1031 $ndirs = -1;
806 } else { 1032 } else {
807 # if nlink == 2, we are finished 1033 # if nlink == 2, we are finished
808 # on non-posix-fs's, we rely on nlink < 2 1034 # for non-posix-fs's, we rely on nlink < 2
809 $ndirs = (stat _)[3] - 2 1035 $ndirs = (stat _)[3] - 2
810 or return $grp->result ([], $entries); 1036 or return $grp->result ([], $entries);
811 } 1037 }
812 1038
813 # sort into likely dirs and likely nondirs
814 # dirs == files without ".", short entries first
815 $entries = [map $_->[0],
816 sort { $b->[1] cmp $a->[1] }
817 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
818 @$entries];
819
820 my (@dirs, @nondirs); 1039 my (@dirs, @nondirs);
821 1040
822 my $statgrp = add $grp aio_group sub { 1041 my $statgrp = add $grp aio_group sub {
823 $grp->result (\@dirs, \@nondirs); 1042 $grp->result (\@dirs, \@nondirs);
824 }; 1043 };
825 1044
826 limit $statgrp $maxreq; 1045 limit $statgrp $maxreq;
827 feed $statgrp sub { 1046 feed $statgrp sub {
828 return unless @$entries; 1047 return unless @$entries;
829 my $entry = pop @$entries; 1048 my $entry = shift @$entries;
830 1049
831 aioreq_pri $pri; 1050 aioreq_pri $pri;
1051 $wd->[1] = "$entry/.";
832 add $statgrp aio_stat "$path/$entry/.", sub { 1052 add $statgrp aio_stat $wd, sub {
833 if ($_[0] < 0) { 1053 if ($_[0] < 0) {
834 push @nondirs, $entry; 1054 push @nondirs, $entry;
835 } else { 1055 } else {
836 # need to check for real directory 1056 # need to check for real directory
837 aioreq_pri $pri; 1057 aioreq_pri $pri;
1058 $wd->[1] = $entry;
838 add $statgrp aio_lstat "$path/$entry", sub { 1059 add $statgrp aio_lstat $wd, sub {
839 if (-d _) { 1060 if (-d _) {
840 push @dirs, $entry; 1061 push @dirs, $entry;
841 1062
842 unless (--$ndirs) { 1063 unless (--$ndirs) {
843 push @nondirs, @$entries; 1064 push @nondirs, @$entries;
851 }; 1072 };
852 }; 1073 };
853 }; 1074 };
854 }; 1075 };
855 }; 1076 };
856
857 $grp
858 } 1077 };
1078
1079 $grp
859} 1080}
860 1081
861=item aio_rmtree $path, $callback->($status) 1082=item aio_rmtree $pathname, $callback->($status)
862 1083
863Delete a directory tree starting (and including) C<$path>, return the 1084Delete a directory tree starting (and including) C<$path>, return the
864status of the final C<rmdir> only. This is a composite request that 1085status of the final C<rmdir> only. This is a composite request that
865uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1086uses C<aio_scandir> to recurse into and rmdir directories, and unlink
866everything else. 1087everything else.
867 1088
868=cut 1089=cut
869 1090
870sub aio_rmtree; 1091sub aio_rmtree;
871sub aio_rmtree($;$) { 1092sub aio_rmtree($;$) {
872 aio_block {
873 my ($path, $cb) = @_; 1093 my ($path, $cb) = @_;
874 1094
875 my $pri = aioreq_pri; 1095 my $pri = aioreq_pri;
876 my $grp = aio_group $cb; 1096 my $grp = aio_group $cb;
877 1097
878 aioreq_pri $pri; 1098 aioreq_pri $pri;
879 add $grp aio_scandir $path, 0, sub { 1099 add $grp aio_scandir $path, 0, sub {
880 my ($dirs, $nondirs) = @_; 1100 my ($dirs, $nondirs) = @_;
881 1101
882 my $dirgrp = aio_group sub { 1102 my $dirgrp = aio_group sub {
883 add $grp aio_rmdir $path, sub { 1103 add $grp aio_rmdir $path, sub {
884 $grp->result ($_[0]); 1104 $grp->result ($_[0]);
885 };
886 }; 1105 };
887
888 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
889 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
890
891 add $grp $dirgrp;
892 }; 1106 };
893 1107
894 $grp 1108 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
1109 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
1110
1111 add $grp $dirgrp;
895 } 1112 };
1113
1114 $grp
896} 1115}
1116
1117=item aio_sync $callback->($status)
1118
1119Asynchronously call sync and call the callback when finished.
897 1120
898=item aio_fsync $fh, $callback->($status) 1121=item aio_fsync $fh, $callback->($status)
899 1122
900Asynchronously call fsync on the given filehandle and call the callback 1123Asynchronously call fsync on the given filehandle and call the callback
901with the fsync result code. 1124with the fsync result code.
905Asynchronously call fdatasync on the given filehandle and call the 1128Asynchronously call fdatasync on the given filehandle and call the
906callback with the fdatasync result code. 1129callback with the fdatasync result code.
907 1130
908If this call isn't available because your OS lacks it or it couldn't be 1131If this call isn't available because your OS lacks it or it couldn't be
909detected, it will be emulated by calling C<fsync> instead. 1132detected, it will be emulated by calling C<fsync> instead.
1133
1134=item aio_syncfs $fh, $callback->($status)
1135
1136Asynchronously call the syncfs syscall to sync the filesystem associated
1137to the given filehandle and call the callback with the syncfs result
1138code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1139errno to C<ENOSYS> nevertheless.
1140
1141=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1142
1143Sync the data portion of the file specified by C<$offset> and C<$length>
1144to disk (but NOT the metadata), by calling the Linux-specific
1145sync_file_range call. If sync_file_range is not available or it returns
1146ENOSYS, then fdatasync or fsync is being substituted.
1147
1148C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1149C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1150C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1151manpage for details.
1152
1153=item aio_pathsync $pathname, $callback->($status)
1154
1155This request tries to open, fsync and close the given path. This is a
1156composite request intended to sync directories after directory operations
1157(E.g. rename). This might not work on all operating systems or have any
1158specific effect, but usually it makes sure that directory changes get
1159written to disc. It works for anything that can be opened for read-only,
1160not just directories.
1161
1162Future versions of this function might fall back to other methods when
1163C<fsync> on the directory fails (such as calling C<sync>).
1164
1165Passes C<0> when everything went ok, and C<-1> on error.
1166
1167=cut
1168
1169sub aio_pathsync($;$) {
1170 my ($path, $cb) = @_;
1171
1172 my $pri = aioreq_pri;
1173 my $grp = aio_group $cb;
1174
1175 aioreq_pri $pri;
1176 add $grp aio_open $path, O_RDONLY, 0, sub {
1177 my ($fh) = @_;
1178 if ($fh) {
1179 aioreq_pri $pri;
1180 add $grp aio_fsync $fh, sub {
1181 $grp->result ($_[0]);
1182
1183 aioreq_pri $pri;
1184 add $grp aio_close $fh;
1185 };
1186 } else {
1187 $grp->result (-1);
1188 }
1189 };
1190
1191 $grp
1192}
1193
1194=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1195
1196This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1197scalars (see the C<IO::AIO::mmap> function, although it also works on data
1198scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1199scalar must only be modified in-place while an aio operation is pending on
1200it).
1201
1202It calls the C<msync> function of your OS, if available, with the memory
1203area starting at C<$offset> in the string and ending C<$length> bytes
1204later. If C<$length> is negative, counts from the end, and if C<$length>
1205is C<undef>, then it goes till the end of the string. The flags can be
1206a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1207C<IO::AIO::MS_SYNC>.
1208
1209=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1210
1211This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1212scalars.
1213
1214It touches (reads or writes) all memory pages in the specified
1215range inside the scalar. All caveats and parameters are the same
1216as for C<aio_msync>, above, except for flags, which must be either
1217C<0> (which reads all pages and ensures they are instantiated) or
1218C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1219writing an octet from it, which dirties the page).
1220
1221=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1222
1223This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1224scalars.
1225
1226It reads in all the pages of the underlying storage into memory (if any)
1227and locks them, so they are not getting swapped/paged out or removed.
1228
1229If C<$length> is undefined, then the scalar will be locked till the end.
1230
1231On systems that do not implement C<mlock>, this function returns C<-1>
1232and sets errno to C<ENOSYS>.
1233
1234Note that the corresponding C<munlock> is synchronous and is
1235documented under L<MISCELLANEOUS FUNCTIONS>.
1236
1237Example: open a file, mmap and mlock it - both will be undone when
1238C<$data> gets destroyed.
1239
1240 open my $fh, "<", $path or die "$path: $!";
1241 my $data;
1242 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1243 aio_mlock $data; # mlock in background
1244
1245=item aio_mlockall $flags, $callback->($status)
1246
1247Calls the C<mlockall> function with the given C<$flags> (a combination of
1248C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1249
1250On systems that do not implement C<mlockall>, this function returns C<-1>
1251and sets errno to C<ENOSYS>.
1252
1253Note that the corresponding C<munlockall> is synchronous and is
1254documented under L<MISCELLANEOUS FUNCTIONS>.
1255
1256Example: asynchronously lock all current and future pages into memory.
1257
1258 aio_mlockall IO::AIO::MCL_FUTURE;
1259
1260=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1261
1262Queries the extents of the given file (by calling the Linux FIEMAP ioctl,
1263see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the
1264C<ioctl> is not available on your OS, then this rquiest will fail with
1265C<ENOSYS>.
1266
1267C<$start> is the starting offset to query extents for, C<$length> is the
1268size of the range to query - if it is C<undef>, then the whole file will
1269be queried.
1270
1271C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1272C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1273exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1274the data portion.
1275
1276C<$count> is the maximum number of extent records to return. If it is
1277C<undef>, then IO::AIO queries all extents of the file. As a very special
1278case, if it is C<0>, then the callback receives the number of extents
1279instead of the extents themselves.
1280
1281If an error occurs, the callback receives no arguments. The special
1282C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1283
1284Otherwise, the callback receives an array reference with extent
1285structures. Each extent structure is an array reference itself, with the
1286following members:
1287
1288 [$logical, $physical, $length, $flags]
1289
1290Flags is any combination of the following flag values (typically either C<0>
1291or C<IO::AIO::FIEMAP_EXTENT_LAST>):
1292
1293C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1294C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1295C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1296C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1297C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1298C<IO::AIO::FIEMAP_EXTENT_SHARED>.
910 1299
911=item aio_group $callback->(...) 1300=item aio_group $callback->(...)
912 1301
913This is a very special aio request: Instead of doing something, it is a 1302This is a very special aio request: Instead of doing something, it is a
914container for other aio requests, which is useful if you want to bundle 1303container for other aio requests, which is useful if you want to bundle
952immense (it blocks a thread for a long time) so do not use this function 1341immense (it blocks a thread for a long time) so do not use this function
953except to put your application under artificial I/O pressure. 1342except to put your application under artificial I/O pressure.
954 1343
955=back 1344=back
956 1345
1346
1347=head2 IO::AIO::WD - multiple working directories
1348
1349Your process only has one current working directory, which is used by all
1350threads. This makes it hard to use relative paths (some other component
1351could call C<chdir> at any time, and it is hard to control when the path
1352will be used by IO::AIO).
1353
1354One solution for this is to always use absolute paths. This usually works,
1355but can be quite slow (the kernel has to walk the whole path on every
1356access), and can also be a hassle to implement.
1357
1358Newer POSIX systems have a number of functions (openat, fdopendir,
1359futimensat and so on) that make it possible to specify working directories
1360per operation.
1361
1362For portability, and because the clowns who "designed", or shall I write,
1363perpetrated this new interface were obviously half-drunk, this abstraction
1364cannot be perfect, though.
1365
1366IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1367object. This object stores the canonicalised, absolute version of the
1368path, and on systems that allow it, also a directory file descriptor.
1369
1370Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1371or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1372object and a pathname instead (or the IO::AIO::WD object alone, which
1373gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1374IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1375to that IO::AIO::WD object.
1376
1377For example, to get a wd object for F</etc> and then stat F<passwd>
1378inside, you would write:
1379
1380 aio_wd "/etc", sub {
1381 my $etcdir = shift;
1382
1383 # although $etcdir can be undef on error, there is generally no reason
1384 # to check for errors here, as aio_stat will fail with ENOENT
1385 # when $etcdir is undef.
1386
1387 aio_stat [$etcdir, "passwd"], sub {
1388 # yay
1389 };
1390 };
1391
1392That C<aio_wd> is a request and not a normal function shows that creating
1393an IO::AIO::WD object is itself a potentially blocking operation, which is
1394why it is done asynchronously.
1395
1396To stat the directory obtained with C<aio_wd> above, one could write
1397either of the following three request calls:
1398
1399 aio_lstat "/etc" , sub { ... # pathname as normal string
1400 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1401 aio_lstat $wd , sub { ... # shorthand for the previous
1402
1403As with normal pathnames, IO::AIO keeps a copy of the working directory
1404object and the pathname string, so you could write the following without
1405causing any issues due to C<$path> getting reused:
1406
1407 my $path = [$wd, undef];
1408
1409 for my $name (qw(abc def ghi)) {
1410 $path->[1] = $name;
1411 aio_stat $path, sub {
1412 # ...
1413 };
1414 }
1415
1416There are some caveats: when directories get renamed (or deleted), the
1417pathname string doesn't change, so will point to the new directory (or
1418nowhere at all), while the directory fd, if available on the system,
1419will still point to the original directory. Most functions accepting a
1420pathname will use the directory fd on newer systems, and the string on
1421older systems. Some functions (such as realpath) will always rely on the
1422string form of the pathname.
1423
1424So this fucntionality is mainly useful to get some protection against
1425C<chdir>, to easily get an absolute path out of a relative path for future
1426reference, and to speed up doing many operations in the same directory
1427(e.g. when stat'ing all files in a directory).
1428
1429The following functions implement this working directory abstraction:
1430
1431=over 4
1432
1433=item aio_wd $pathname, $callback->($wd)
1434
1435Asynchonously canonicalise the given pathname and convert it to an
1436IO::AIO::WD object representing it. If possible and supported on the
1437system, also open a directory fd to speed up pathname resolution relative
1438to this working directory.
1439
1440If something goes wrong, then C<undef> is passwd to the callback instead
1441of a working directory object and C<$!> is set appropriately. Since
1442passing C<undef> as working directory component of a pathname fails the
1443request with C<ENOENT>, there is often no need for error checking in the
1444C<aio_wd> callback, as future requests using the value will fail in the
1445expected way.
1446
1447If this call isn't available because your OS lacks it or it couldn't be
1448detected, it will be emulated by calling C<fsync> instead.
1449
1450=item IO::AIO::CWD
1451
1452This is a compiletime constant (object) that represents the process
1453current working directory.
1454
1455Specifying this object as working directory object for a pathname is as
1456if the pathname would be specified directly, without a directory object,
1457e.g., these calls are functionally identical:
1458
1459 aio_stat "somefile", sub { ... };
1460 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1461
1462=back
1463
1464
957=head2 IO::AIO::REQ CLASS 1465=head2 IO::AIO::REQ CLASS
958 1466
959All non-aggregate C<aio_*> functions return an object of this class when 1467All non-aggregate C<aio_*> functions return an object of this class when
960called in non-void context. 1468called in non-void context.
961 1469
964=item cancel $req 1472=item cancel $req
965 1473
966Cancels the request, if possible. Has the effect of skipping execution 1474Cancels the request, if possible. Has the effect of skipping execution
967when entering the B<execute> state and skipping calling the callback when 1475when entering the B<execute> state and skipping calling the callback when
968entering the the B<result> state, but will leave the request otherwise 1476entering the the B<result> state, but will leave the request otherwise
969untouched. That means that requests that currently execute will not be 1477untouched (with the exception of readdir). That means that requests that
970stopped and resources held by the request will not be freed prematurely. 1478currently execute will not be stopped and resources held by the request
1479will not be freed prematurely.
971 1480
972=item cb $req $callback->(...) 1481=item cb $req $callback->(...)
973 1482
974Replace (or simply set) the callback registered to the request. 1483Replace (or simply set) the callback registered to the request.
975 1484
1026Their lifetime, simplified, looks like this: when they are empty, they 1535Their lifetime, simplified, looks like this: when they are empty, they
1027will finish very quickly. If they contain only requests that are in the 1536will finish very quickly. If they contain only requests that are in the
1028C<done> state, they will also finish. Otherwise they will continue to 1537C<done> state, they will also finish. Otherwise they will continue to
1029exist. 1538exist.
1030 1539
1031That means after creating a group you have some time to add requests. And 1540That means after creating a group you have some time to add requests
1032in the callbacks of those requests, you can add further requests to the 1541(precisely before the callback has been invoked, which is only done within
1033group. And only when all those requests have finished will the the group 1542the C<poll_cb>). And in the callbacks of those requests, you can add
1034itself finish. 1543further requests to the group. And only when all those requests have
1544finished will the the group itself finish.
1035 1545
1036=over 4 1546=over 4
1037 1547
1038=item add $grp ... 1548=item add $grp ...
1039 1549
1048=item $grp->cancel_subs 1558=item $grp->cancel_subs
1049 1559
1050Cancel all subrequests and clears any feeder, but not the group request 1560Cancel all subrequests and clears any feeder, but not the group request
1051itself. Useful when you queued a lot of events but got a result early. 1561itself. Useful when you queued a lot of events but got a result early.
1052 1562
1563The group request will finish normally (you cannot add requests to the
1564group).
1565
1053=item $grp->result (...) 1566=item $grp->result (...)
1054 1567
1055Set the result value(s) that will be passed to the group callback when all 1568Set the result value(s) that will be passed to the group callback when all
1056subrequests have finished and set thre groups errno to the current value 1569subrequests have finished and set the groups errno to the current value
1057of errno (just like calling C<errno> without an error number). By default, 1570of errno (just like calling C<errno> without an error number). By default,
1058no argument will be passed and errno is zero. 1571no argument will be passed and errno is zero.
1059 1572
1060=item $grp->errno ([$errno]) 1573=item $grp->errno ([$errno])
1061 1574
1072=item feed $grp $callback->($grp) 1585=item feed $grp $callback->($grp)
1073 1586
1074Sets a feeder/generator on this group: every group can have an attached 1587Sets a feeder/generator on this group: every group can have an attached
1075generator that generates requests if idle. The idea behind this is that, 1588generator that generates requests if idle. The idea behind this is that,
1076although you could just queue as many requests as you want in a group, 1589although you could just queue as many requests as you want in a group,
1077this might starve other requests for a potentially long time. For 1590this might starve other requests for a potentially long time. For example,
1078example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1591C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1079requests, delaying any later requests for a long time. 1592requests, delaying any later requests for a long time.
1080 1593
1081To avoid this, and allow incremental generation of requests, you can 1594To avoid this, and allow incremental generation of requests, you can
1082instead a group and set a feeder on it that generates those requests. The 1595instead a group and set a feeder on it that generates those requests. The
1083feed callback will be called whenever there are few enough (see C<limit>, 1596feed callback will be called whenever there are few enough (see C<limit>,
1088not impose any limits). 1601not impose any limits).
1089 1602
1090If the feed does not queue more requests when called, it will be 1603If the feed does not queue more requests when called, it will be
1091automatically removed from the group. 1604automatically removed from the group.
1092 1605
1093If the feed limit is C<0>, it will be set to C<2> automatically. 1606If the feed limit is C<0> when this method is called, it will be set to
1607C<2> automatically.
1094 1608
1095Example: 1609Example:
1096 1610
1097 # stat all files in @files, but only ever use four aio requests concurrently: 1611 # stat all files in @files, but only ever use four aio requests concurrently:
1098 1612
1110Sets the feeder limit for the group: The feeder will be called whenever 1624Sets the feeder limit for the group: The feeder will be called whenever
1111the group contains less than this many requests. 1625the group contains less than this many requests.
1112 1626
1113Setting the limit to C<0> will pause the feeding process. 1627Setting the limit to C<0> will pause the feeding process.
1114 1628
1629The default value for the limit is C<0>, but note that setting a feeder
1630automatically bumps it up to C<2>.
1631
1115=back 1632=back
1116 1633
1117=head2 SUPPORT FUNCTIONS 1634=head2 SUPPORT FUNCTIONS
1118 1635
1119=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1636=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1121=over 4 1638=over 4
1122 1639
1123=item $fileno = IO::AIO::poll_fileno 1640=item $fileno = IO::AIO::poll_fileno
1124 1641
1125Return the I<request result pipe file descriptor>. This filehandle must be 1642Return the I<request result pipe file descriptor>. This filehandle must be
1126polled for reading by some mechanism outside this module (e.g. Event or 1643polled for reading by some mechanism outside this module (e.g. EV, Glib,
1127select, see below or the SYNOPSIS). If the pipe becomes readable you have 1644select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1128to call C<poll_cb> to check the results. 1645you have to call C<poll_cb> to check the results.
1129 1646
1130See C<poll_cb> for an example. 1647See C<poll_cb> for an example.
1131 1648
1132=item IO::AIO::poll_cb 1649=item IO::AIO::poll_cb
1133 1650
1134Process some outstanding events on the result pipe. You have to call this 1651Process some outstanding events on the result pipe. You have to call
1135regularly. Returns the number of events processed. Returns immediately 1652this regularly. Returns C<0> if all events could be processed (or there
1136when no events are outstanding. The amount of events processed depends on 1653were no events to process), or C<-1> if it returned earlier for whatever
1137the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1654reason. Returns immediately when no events are outstanding. The amount of
1655events processed depends on the settings of C<IO::AIO::max_poll_req> and
1656C<IO::AIO::max_poll_time>.
1138 1657
1139If not all requests were processed for whatever reason, the filehandle 1658If not all requests were processed for whatever reason, the filehandle
1140will still be ready when C<poll_cb> returns. 1659will still be ready when C<poll_cb> returns, so normally you don't have to
1660do anything special to have it called later.
1661
1662Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1663ready, it can be beneficial to call this function from loops which submit
1664a lot of requests, to make sure the results get processed when they become
1665available and not just when the loop is finished and the event loop takes
1666over again. This function returns very fast when there are no outstanding
1667requests.
1141 1668
1142Example: Install an Event watcher that automatically calls 1669Example: Install an Event watcher that automatically calls
1143IO::AIO::poll_cb with high priority: 1670IO::AIO::poll_cb with high priority (more examples can be found in the
1671SYNOPSIS section, at the top of this document):
1144 1672
1145 Event->io (fd => IO::AIO::poll_fileno, 1673 Event->io (fd => IO::AIO::poll_fileno,
1146 poll => 'r', async => 1, 1674 poll => 'r', async => 1,
1147 cb => \&IO::AIO::poll_cb); 1675 cb => \&IO::AIO::poll_cb);
1676
1677=item IO::AIO::poll_wait
1678
1679If there are any outstanding requests and none of them in the result
1680phase, wait till the result filehandle becomes ready for reading (simply
1681does a C<select> on the filehandle. This is useful if you want to
1682synchronously wait for some requests to finish).
1683
1684See C<nreqs> for an example.
1685
1686=item IO::AIO::poll
1687
1688Waits until some requests have been handled.
1689
1690Returns the number of requests processed, but is otherwise strictly
1691equivalent to:
1692
1693 IO::AIO::poll_wait, IO::AIO::poll_cb
1694
1695=item IO::AIO::flush
1696
1697Wait till all outstanding AIO requests have been handled.
1698
1699Strictly equivalent to:
1700
1701 IO::AIO::poll_wait, IO::AIO::poll_cb
1702 while IO::AIO::nreqs;
1148 1703
1149=item IO::AIO::max_poll_reqs $nreqs 1704=item IO::AIO::max_poll_reqs $nreqs
1150 1705
1151=item IO::AIO::max_poll_time $seconds 1706=item IO::AIO::max_poll_time $seconds
1152 1707
1177 # use a low priority so other tasks have priority 1732 # use a low priority so other tasks have priority
1178 Event->io (fd => IO::AIO::poll_fileno, 1733 Event->io (fd => IO::AIO::poll_fileno,
1179 poll => 'r', nice => 1, 1734 poll => 'r', nice => 1,
1180 cb => &IO::AIO::poll_cb); 1735 cb => &IO::AIO::poll_cb);
1181 1736
1182=item IO::AIO::poll_wait
1183
1184If there are any outstanding requests and none of them in the result
1185phase, wait till the result filehandle becomes ready for reading (simply
1186does a C<select> on the filehandle. This is useful if you want to
1187synchronously wait for some requests to finish).
1188
1189See C<nreqs> for an example.
1190
1191=item IO::AIO::poll
1192
1193Waits until some requests have been handled.
1194
1195Returns the number of requests processed, but is otherwise strictly
1196equivalent to:
1197
1198 IO::AIO::poll_wait, IO::AIO::poll_cb
1199
1200=item IO::AIO::flush
1201
1202Wait till all outstanding AIO requests have been handled.
1203
1204Strictly equivalent to:
1205
1206 IO::AIO::poll_wait, IO::AIO::poll_cb
1207 while IO::AIO::nreqs;
1208
1209=back 1737=back
1210 1738
1211=head3 CONTROLLING THE NUMBER OF THREADS 1739=head3 CONTROLLING THE NUMBER OF THREADS
1212 1740
1213=over 1741=over
1246 1774
1247Under normal circumstances you don't need to call this function. 1775Under normal circumstances you don't need to call this function.
1248 1776
1249=item IO::AIO::max_idle $nthreads 1777=item IO::AIO::max_idle $nthreads
1250 1778
1251Limit the number of threads (default: 4) that are allowed to idle (i.e., 1779Limit the number of threads (default: 4) that are allowed to idle
1252threads that did not get a request to process within 10 seconds). That 1780(i.e., threads that did not get a request to process within the idle
1253means if a thread becomes idle while C<$nthreads> other threads are also 1781timeout (default: 10 seconds). That means if a thread becomes idle while
1254idle, it will free its resources and exit. 1782C<$nthreads> other threads are also idle, it will free its resources and
1783exit.
1255 1784
1256This is useful when you allow a large number of threads (e.g. 100 or 1000) 1785This is useful when you allow a large number of threads (e.g. 100 or 1000)
1257to allow for extremely high load situations, but want to free resources 1786to allow for extremely high load situations, but want to free resources
1258under normal circumstances (1000 threads can easily consume 30MB of RAM). 1787under normal circumstances (1000 threads can easily consume 30MB of RAM).
1259 1788
1260The default is probably ok in most situations, especially if thread 1789The default is probably ok in most situations, especially if thread
1261creation is fast. If thread creation is very slow on your system you might 1790creation is fast. If thread creation is very slow on your system you might
1262want to use larger values. 1791want to use larger values.
1263 1792
1793=item IO::AIO::idle_timeout $seconds
1794
1795Sets the minimum idle timeout (default 10) after which worker threads are
1796allowed to exit. SEe C<IO::AIO::max_idle>.
1797
1264=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1798=item IO::AIO::max_outstanding $maxreqs
1799
1800Sets the maximum number of outstanding requests to C<$nreqs>. If
1801you do queue up more than this number of requests, the next call to
1802C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1803C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1804longer exceeded.
1805
1806In other words, this setting does not enforce a queue limit, but can be
1807used to make poll functions block if the limit is exceeded.
1265 1808
1266This is a very bad function to use in interactive programs because it 1809This is a very bad function to use in interactive programs because it
1267blocks, and a bad way to reduce concurrency because it is inexact: Better 1810blocks, and a bad way to reduce concurrency because it is inexact: Better
1268use an C<aio_group> together with a feed callback. 1811use an C<aio_group> together with a feed callback.
1269 1812
1270Sets the maximum number of outstanding requests to C<$nreqs>. If you 1813It's main use is in scripts without an event loop - when you want to stat
1271do queue up more than this number of requests, the next call to the 1814a lot of files, you can write somehting like this:
1272C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1273function will block until the limit is no longer exceeded.
1274 1815
1275The default value is very large, so there is no practical limit on the 1816 IO::AIO::max_outstanding 32;
1276number of outstanding requests.
1277 1817
1278You can still queue as many requests as you want. Therefore, 1818 for my $path (...) {
1279C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1819 aio_stat $path , ...;
1280as a stop gap to shield against fatal memory overflow (with large values). 1820 IO::AIO::poll_cb;
1821 }
1822
1823 IO::AIO::flush;
1824
1825The call to C<poll_cb> inside the loop will normally return instantly, but
1826as soon as more thna C<32> reqeusts are in-flight, it will block until
1827some requests have been handled. This keeps the loop from pushing a large
1828number of C<aio_stat> requests onto the queue.
1829
1830The default value for C<max_outstanding> is very large, so there is no
1831practical limit on the number of outstanding requests.
1281 1832
1282=back 1833=back
1283 1834
1284=head3 STATISTICAL INFORMATION 1835=head3 STATISTICAL INFORMATION
1285 1836
1305Returns the number of requests currently in the pending state (executed, 1856Returns the number of requests currently in the pending state (executed,
1306but not yet processed by poll_cb). 1857but not yet processed by poll_cb).
1307 1858
1308=back 1859=back
1309 1860
1861=head3 MISCELLANEOUS FUNCTIONS
1862
1863IO::AIO implements some functions that might be useful, but are not
1864asynchronous.
1865
1866=over 4
1867
1868=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1869
1870Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1871but is blocking (this makes most sense if you know the input data is
1872likely cached already and the output filehandle is set to non-blocking
1873operations).
1874
1875Returns the number of bytes copied, or C<-1> on error.
1876
1877=item IO::AIO::fadvise $fh, $offset, $len, $advice
1878
1879Simply calls the C<posix_fadvise> function (see its
1880manpage for details). The following advice constants are
1881available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1882C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1883C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1884
1885On systems that do not implement C<posix_fadvise>, this function returns
1886ENOSYS, otherwise the return value of C<posix_fadvise>.
1887
1888=item IO::AIO::madvise $scalar, $offset, $len, $advice
1889
1890Simply calls the C<posix_madvise> function (see its
1891manpage for details). The following advice constants are
1892available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1893C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1894
1895On systems that do not implement C<posix_madvise>, this function returns
1896ENOSYS, otherwise the return value of C<posix_madvise>.
1897
1898=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1899
1900Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1901$scalar (see its manpage for details). The following protect
1902constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1903C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1904
1905On systems that do not implement C<mprotect>, this function returns
1906ENOSYS, otherwise the return value of C<mprotect>.
1907
1908=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1909
1910Memory-maps a file (or anonymous memory range) and attaches it to the
1911given C<$scalar>, which will act like a string scalar.
1912
1913The only operations allowed on the scalar are C<substr>/C<vec> that don't
1914change the string length, and most read-only operations such as copying it
1915or searching it with regexes and so on.
1916
1917Anything else is unsafe and will, at best, result in memory leaks.
1918
1919The memory map associated with the C<$scalar> is automatically removed
1920when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1921C<IO::AIO::munmap> functions are called.
1922
1923This calls the C<mmap>(2) function internally. See your system's manual
1924page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1925
1926The C<$length> must be larger than zero and smaller than the actual
1927filesize.
1928
1929C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1930C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1931
1932C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1933C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1934not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1935(which is set to C<MAP_ANON> if your system only provides this
1936constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1937C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1938C<IO::AIO::MAP_NONBLOCK>
1939
1940If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1941
1942C<$offset> is the offset from the start of the file - it generally must be
1943a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1944
1945Example:
1946
1947 use Digest::MD5;
1948 use IO::AIO;
1949
1950 open my $fh, "<verybigfile"
1951 or die "$!";
1952
1953 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1954 or die "verybigfile: $!";
1955
1956 my $fast_md5 = md5 $data;
1957
1958=item IO::AIO::munmap $scalar
1959
1960Removes a previous mmap and undefines the C<$scalar>.
1961
1962=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1963
1964Calls the C<munlock> function, undoing the effects of a previous
1965C<aio_mlock> call (see its description for details).
1966
1967=item IO::AIO::munlockall
1968
1969Calls the C<munlockall> function.
1970
1971On systems that do not implement C<munlockall>, this function returns
1972ENOSYS, otherwise the return value of C<munlockall>.
1973
1974=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1975
1976Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1977C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
1978should be the file offset.
1979
1980The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
1981C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
1982C<IO::AIO::SPLICE_F_GIFT>.
1983
1984See the C<splice(2)> manpage for details.
1985
1986=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
1987
1988Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
1989description for C<IO::AIO::splice> above for details.
1990
1991=back
1992
1310=cut 1993=cut
1311 1994
1312min_parallel 8; 1995min_parallel 8;
1313 1996
1314END { flush } 1997END { flush }
1315 1998
13161; 19991;
1317 2000
2001=head1 EVENT LOOP INTEGRATION
2002
2003It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
2004automatically into many event loops:
2005
2006 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
2007 use AnyEvent::AIO;
2008
2009You can also integrate IO::AIO manually into many event loops, here are
2010some examples of how to do this:
2011
2012 # EV integration
2013 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
2014
2015 # Event integration
2016 Event->io (fd => IO::AIO::poll_fileno,
2017 poll => 'r',
2018 cb => \&IO::AIO::poll_cb);
2019
2020 # Glib/Gtk2 integration
2021 add_watch Glib::IO IO::AIO::poll_fileno,
2022 in => sub { IO::AIO::poll_cb; 1 };
2023
2024 # Tk integration
2025 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
2026 readable => \&IO::AIO::poll_cb);
2027
2028 # Danga::Socket integration
2029 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
2030 \&IO::AIO::poll_cb);
2031
1318=head2 FORK BEHAVIOUR 2032=head2 FORK BEHAVIOUR
1319 2033
1320This module should do "the right thing" when the process using it forks: 2034Usage of pthreads in a program changes the semantics of fork
2035considerably. Specifically, only async-safe functions can be called after
2036fork. Perl doesn't know about this, so in general, you cannot call fork
2037with defined behaviour in perl if pthreads are involved. IO::AIO uses
2038pthreads, so this applies, but many other extensions and (for inexplicable
2039reasons) perl itself often is linked against pthreads, so this limitation
2040applies to quite a lot of perls.
1321 2041
1322Before the fork, IO::AIO enters a quiescent state where no requests 2042This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1323can be added in other threads and no results will be processed. After 2043only works in the process that loaded it. Forking is fully supported, but
1324the fork the parent simply leaves the quiescent state and continues 2044using IO::AIO in the child is not.
1325request/result processing, while the child frees the request/result queue
1326(so that the requests started before the fork will only be handled in the
1327parent). Threads will be started on demand until the limit set in the
1328parent process has been reached again.
1329 2045
1330In short: the parent will, after a short pause, continue as if fork had 2046You might get around by not I<using> IO::AIO before (or after)
1331not been called, while the child will act as if IO::AIO has not been used 2047forking. You could also try to call the L<IO::AIO::reinit> function in the
1332yet. 2048child:
2049
2050=over 4
2051
2052=item IO::AIO::reinit
2053
2054Abandons all current requests and I/O threads and simply reinitialises all
2055data structures. This is not an operation supported by any standards, but
2056happens to work on GNU/Linux and some newer BSD systems.
2057
2058The only reasonable use for this function is to call it after forking, if
2059C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
2060the process will result in undefined behaviour. Calling it at any time
2061will also result in any undefined (by POSIX) behaviour.
2062
2063=back
1333 2064
1334=head2 MEMORY USAGE 2065=head2 MEMORY USAGE
1335 2066
1336Per-request usage: 2067Per-request usage:
1337 2068
1354 2085
1355Known bugs will be fixed in the next release. 2086Known bugs will be fixed in the next release.
1356 2087
1357=head1 SEE ALSO 2088=head1 SEE ALSO
1358 2089
1359L<Coro::AIO>. 2090L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2091more natural syntax.
1360 2092
1361=head1 AUTHOR 2093=head1 AUTHOR
1362 2094
1363 Marc Lehmann <schmorp@schmorp.de> 2095 Marc Lehmann <schmorp@schmorp.de>
1364 http://home.schmorp.de/ 2096 http://home.schmorp.de/

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