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Revision 1.120 by root, Sun Dec 2 21:51:36 2007 UTC vs.
Revision 1.226 by root, Mon May 28 17:00:19 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 = '2.6'; 173 our $VERSION = '4.15';
200 174
201 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
202 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
203 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_fallocate
204 aio_fdatasync aio_pathsync aio_readahead 179 aio_pathsync aio_readahead aio_fiemap
205 aio_rename aio_link aio_move aio_copy aio_group 180 aio_rename aio_link aio_move aio_copy aio_group
206 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
207 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);
208 186
209 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
210 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
211 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
212 nreqs nready npending nthreads 190 nreqs nready npending nthreads
213 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
214 196
215 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
216 198
217 require XSLoader; 199 require XSLoader;
218 XSLoader::load ("IO::AIO", $VERSION); 200 XSLoader::load ("IO::AIO", $VERSION);
219} 201}
220 202
221=head1 FUNCTIONS 203=head1 FUNCTIONS
222 204
223=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::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
278 IO::AIO::munmap $scalar
279 IO::AIO::madvise $scalar, $offset, $length, $advice
280 IO::AIO::mprotect $scalar, $offset, $length, $protect
281 IO::AIO::munlock $scalar, $offset = 0, $length = undef
282 IO::AIO::munlockall
283
284=head2 API NOTES
224 285
225All the C<aio_*> calls are more or less thin wrappers around the syscall 286All the C<aio_*> calls are more or less thin wrappers around the syscall
226with the same name (sans C<aio_>). The arguments are similar or identical, 287with the same name (sans C<aio_>). The arguments are similar or identical,
227and they all accept an additional (and optional) C<$callback> argument 288and they all accept an additional (and optional) C<$callback> argument
228which must be a code reference. This code reference will get called with 289which must be a code reference. This code reference will be called after
229the syscall return code (e.g. most syscalls return C<-1> on error, unlike 290the syscall has been executed in an asynchronous fashion. The results
230perl, which usually delivers "false") as it's sole argument when the given 291of the request will be passed as arguments to the callback (and, if an
231syscall has been executed asynchronously. 292error occured, in C<$!>) - for most requests the syscall return code (e.g.
293most syscalls return C<-1> on error, unlike perl, which usually delivers
294"false").
295
296Some requests (such as C<aio_readdir>) pass the actual results and
297communicate failures by passing C<undef>.
232 298
233All functions expecting a filehandle keep a copy of the filehandle 299All functions expecting a filehandle keep a copy of the filehandle
234internally until the request has finished. 300internally until the request has finished.
235 301
236All functions return request objects of type L<IO::AIO::REQ> that allow 302All functions return request objects of type L<IO::AIO::REQ> that allow
237further manipulation of those requests while they are in-flight. 303further manipulation of those requests while they are in-flight.
238 304
239The pathnames you pass to these routines I<must> be absolute and 305The pathnames you pass to these routines I<should> be absolute. The
240encoded as octets. The reason for the former is that at the time the 306reason for this is that at the time the request is being executed, the
241request is being executed, the current working directory could have 307current working directory could have changed. Alternatively, you can
242changed. Alternatively, you can make sure that you never change the 308make sure that you never change the current working directory anywhere
243current working directory anywhere in the program and then use relative 309in the program and then use relative paths. You can also take advantage
244paths. 310of IO::AIOs working directory abstraction, that lets you specify paths
311relative to some previously-opened "working directory object" - see the
312description of the C<IO::AIO::WD> class later in this document.
245 313
246To encode pathnames as octets, either make sure you either: a) always pass 314To encode pathnames as octets, either make sure you either: a) always pass
247in filenames you got from outside (command line, readdir etc.) without 315in filenames you got from outside (command line, readdir etc.) without
248tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 316tinkering, b) are in your native filesystem encoding, c) use the Encode
249your pathnames to the locale (or other) encoding in effect in the user 317module and encode your pathnames to the locale (or other) encoding in
250environment, d) use Glib::filename_from_unicode on unicode filenames or e) 318effect in the user environment, d) use Glib::filename_from_unicode on
251use something else to ensure your scalar has the correct contents. 319unicode filenames or e) use something else to ensure your scalar has the
320correct contents.
252 321
253This works, btw. independent of the internal UTF-8 bit, which IO::AIO 322This works, btw. independent of the internal UTF-8 bit, which IO::AIO
254handles correctly wether it is set or not. 323handles correctly whether it is set or not.
324
325=head2 AIO REQUEST FUNCTIONS
255 326
256=over 4 327=over 4
257 328
258=item $prev_pri = aioreq_pri [$pri] 329=item $prev_pri = aioreq_pri [$pri]
259 330
306by the umask in effect then the request is being executed, so better never 377by the umask in effect then the request is being executed, so better never
307change the umask. 378change the umask.
308 379
309Example: 380Example:
310 381
311 aio_open "/etc/passwd", O_RDONLY, 0, sub { 382 aio_open "/etc/passwd", IO::AIO::O_RDONLY, 0, sub {
312 if ($_[0]) { 383 if ($_[0]) {
313 print "open successful, fh is $_[0]\n"; 384 print "open successful, fh is $_[0]\n";
314 ... 385 ...
315 } else { 386 } else {
316 die "open failed: $!\n"; 387 die "open failed: $!\n";
317 } 388 }
318 }; 389 };
319 390
391In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
392C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
393following POSIX and non-POSIX constants are available (missing ones on
394your system are, as usual, C<0>):
395
396C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
397C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
398C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
399
320 400
321=item aio_close $fh, $callback->($status) 401=item aio_close $fh, $callback->($status)
322 402
323Asynchronously close a file and call the callback with the result 403Asynchronously close a file and call the callback with the result
324code. 404code.
325 405
326Unfortunately, you can't do this to perl. Perl I<insists> very strongly on 406Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
327closing the file descriptor associated with the filehandle itself. Here is 407closing the file descriptor associated with the filehandle itself.
328what aio_close will try:
329 408
330 1. dup()licate the fd 409Therefore, C<aio_close> will not close the filehandle - instead it will
331 2. asynchronously close() the duplicated fd 410use dup2 to overwrite the file descriptor with the write-end of a pipe
332 3. dup()licate the fd once more 411(the pipe fd will be created on demand and will be cached).
333 4. let perl close() the filehandle
334 5. asynchronously close the duplicated fd
335 412
336The idea is that the first close() flushes stuff to disk that closing an 413Or in other words: the file descriptor will be closed, but it will not be
337fd will flush, so when perl closes the fd, nothing much will need to be 414free for reuse until the perl filehandle is closed.
338flushed. The second async. close() will then flush stuff to disk that
339closing the last fd to the file will flush.
340
341Just FYI, SuSv3 has this to say on close:
342
343 All outstanding record locks owned by the process on the file
344 associated with the file descriptor shall be removed.
345
346 If fildes refers to a socket, close() shall cause the socket to be
347 destroyed. ... close() shall block for up to the current linger
348 interval until all data is transmitted.
349 [this actually sounds like a specification bug, but who knows]
350
351And at least Linux additionally actually flushes stuff on every close,
352even when the file itself is still open.
353
354Sounds enourmously inefficient and complicated? Yes... please show me how
355to nuke perl's fd out of existence...
356 415
357=cut 416=cut
358 417
359sub aio_close($;$) { 418=item aio_seek $fh, $offset, $whence, $callback->($offs)
360 aio_block {
361 my ($fh, $cb) = @_;
362 419
363 my $pri = aioreq_pri; 420Seeks the filehandle to the new C<$offset>, similarly to perl's
364 my $grp = aio_group $cb; 421C<sysseek>. The C<$whence> can use the traditional values (C<0> for
422C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
423C<IO::AIO::SEEK_END>).
365 424
366 my $fd = fileno $fh; 425The resulting absolute offset will be passed to the callback, or C<-1> in
426case of an error.
367 427
368 defined $fd or Carp::croak "aio_close called with fd-less filehandle"; 428In theory, the C<$whence> constants could be different than the
429corresponding values from L<Fcntl>, but perl guarantees they are the same,
430so don't panic.
369 431
370 # if the dups fail we will simply get EBADF 432As a GNU/Linux (and maybe Solaris) extension, also the constants
371 my $fd2 = _dup $fd; 433C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
372 aioreq_pri $pri; 434could be found. No guarantees about suitability for use in C<aio_seek> or
373 add $grp _aio_close $fd2, sub { 435Perl's C<sysseek> can be made though, although I would naively assume they
374 my $fd2 = _dup $fd; 436"just work".
375 close $fh;
376 aioreq_pri $pri;
377 add $grp _aio_close $fd2, sub {
378 $grp->result ($_[0]);
379 };
380 };
381
382 $grp
383 }
384}
385
386 437
387=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 438=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
388 439
389=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 440=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
390 441
391Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset> 442Reads or writes C<$length> bytes from or to the specified C<$fh> and
392into the scalar given by C<$data> and offset C<$dataoffset> and calls the 443C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
393callback without the actual number of bytes read (or -1 on error, just 444and calls the callback without the actual number of bytes read (or -1 on
394like the syscall). 445error, just like the syscall).
446
447C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
448offset plus the actual number of bytes read.
395 449
396If C<$offset> is undefined, then the current file descriptor offset will 450If C<$offset> is undefined, then the current file descriptor offset will
397be used (and updated), otherwise the file descriptor offset will not be 451be used (and updated), otherwise the file descriptor offset will not be
398changed by these calls. 452changed by these calls.
399 453
400If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>. 454If C<$length> is undefined in C<aio_write>, use the remaining length of
455C<$data>.
401 456
402If C<$dataoffset> is less than zero, it will be counted from the end of 457If C<$dataoffset> is less than zero, it will be counted from the end of
403C<$data>. 458C<$data>.
404 459
405The C<$data> scalar I<MUST NOT> be modified in any way while the request 460The C<$data> scalar I<MUST NOT> be modified in any way while the request
419 474
420Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 475Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
421reading at byte offset C<$in_offset>, and starts writing at the current 476reading at byte offset C<$in_offset>, and starts writing at the current
422file offset of C<$out_fh>. Because of that, it is not safe to issue more 477file offset of C<$out_fh>. Because of that, it is not safe to issue more
423than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 478than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
424other. 479other. The same C<$in_fh> works fine though, as this function does not
480move or use the file offset of C<$in_fh>.
425 481
482Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
483are written, and there is no way to find out how many more bytes have been
484read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
485number of bytes written to C<$out_fh>. Only if the result value equals
486C<$length> one can assume that C<$length> bytes have been read.
487
488Unlike with other C<aio_> functions, it makes a lot of sense to use
489C<aio_sendfile> on non-blocking sockets, as long as one end (typically
490the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
491the socket I/O will be non-blocking. Note, however, that you can run
492into a trap where C<aio_sendfile> reads some data with readahead, then
493fails to write all data, and when the socket is ready the next time, the
494data in the cache is already lost, forcing C<aio_sendfile> to again hit
495the disk. Explicit C<aio_read> + C<aio_write> let's you better control
496resource usage.
497
426This call tries to make use of a native C<sendfile> syscall to provide 498This call tries to make use of a native C<sendfile>-like syscall to
427zero-copy operation. For this to work, C<$out_fh> should refer to a 499provide zero-copy operation. For this to work, C<$out_fh> should refer to
428socket, and C<$in_fh> should refer to mmap'able file. 500a socket, and C<$in_fh> should refer to an mmap'able file.
429 501
430If the native sendfile call fails or is not implemented, it will be 502If a native sendfile cannot be found or it fails with C<ENOSYS>,
431emulated, so you can call C<aio_sendfile> on any type of filehandle 503C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
504C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
432regardless of the limitations of the operating system. 505type of filehandle regardless of the limitations of the operating system.
433 506
434Please note, however, that C<aio_sendfile> can read more bytes from 507As native sendfile syscalls (as practically any non-POSIX interface hacked
435C<$in_fh> than are written, and there is no way to find out how many 508together in a hurry to improve benchmark numbers) tend to be rather buggy
436bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 509on many systems, this implementation tries to work around some known bugs
437provides the number of bytes written to C<$out_fh>. Only if the result 510in Linux and FreeBSD kernels (probably others, too), but that might fail,
438value equals C<$length> one can assume that C<$length> bytes have been 511so you really really should check the return value of C<aio_sendfile> -
439read. 512fewre bytes than expected might have been transferred.
440 513
441 514
442=item aio_readahead $fh,$offset,$length, $callback->($retval) 515=item aio_readahead $fh,$offset,$length, $callback->($retval)
443 516
444C<aio_readahead> populates the page cache with data from a file so that 517C<aio_readahead> populates the page cache with data from a file so that
467 540
468Currently, the stats are always 64-bit-stats, i.e. instead of returning an 541Currently, the stats are always 64-bit-stats, i.e. instead of returning an
469error when stat'ing a large file, the results will be silently truncated 542error when stat'ing a large file, the results will be silently truncated
470unless perl itself is compiled with large file support. 543unless perl itself is compiled with large file support.
471 544
545To help interpret the mode and dev/rdev stat values, IO::AIO offers the
546following constants and functions (if not implemented, the constants will
547be C<0> and the functions will either C<croak> or fall back on traditional
548behaviour).
549
550C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
551C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
552C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
553
472Example: Print the length of F</etc/passwd>: 554Example: Print the length of F</etc/passwd>:
473 555
474 aio_stat "/etc/passwd", sub { 556 aio_stat "/etc/passwd", sub {
475 $_[0] and die "stat failed: $!"; 557 $_[0] and die "stat failed: $!";
476 print "size is ", -s _, "\n"; 558 print "size is ", -s _, "\n";
477 }; 559 };
478 560
479 561
562=item aio_statvfs $fh_or_path, $callback->($statvfs)
563
564Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
565whether a file handle or path was passed.
566
567On success, the callback is passed a hash reference with the following
568members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
569C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
570is passed.
571
572The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
573C<ST_NOSUID>.
574
575The following non-POSIX IO::AIO::ST_* flag masks are defined to
576their correct value when available, or to C<0> on systems that do
577not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
578C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
579C<ST_NODIRATIME> and C<ST_RELATIME>.
580
581Example: stat C</wd> and dump out the data if successful.
582
583 aio_statvfs "/wd", sub {
584 my $f = $_[0]
585 or die "statvfs: $!";
586
587 use Data::Dumper;
588 say Dumper $f;
589 };
590
591 # result:
592 {
593 bsize => 1024,
594 bfree => 4333064312,
595 blocks => 10253828096,
596 files => 2050765568,
597 flag => 4096,
598 favail => 2042092649,
599 bavail => 4333064312,
600 ffree => 2042092649,
601 namemax => 255,
602 frsize => 1024,
603 fsid => 1810
604 }
605
606
480=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 607=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
481 608
482Works like perl's C<utime> function (including the special case of $atime 609Works like perl's C<utime> function (including the special case of $atime
483and $mtime being undef). Fractional times are supported if the underlying 610and $mtime being undef). Fractional times are supported if the underlying
484syscalls support them. 611syscalls support them.
522 649
523Asynchronously unlink (delete) a file and call the callback with the 650Asynchronously unlink (delete) a file and call the callback with the
524result code. 651result code.
525 652
526 653
527=item aio_mknod $path, $mode, $dev, $callback->($status) 654=item aio_mknod $pathname, $mode, $dev, $callback->($status)
528 655
529[EXPERIMENTAL] 656[EXPERIMENTAL]
530 657
531Asynchronously create a device node (or fifo). See mknod(2). 658Asynchronously create a device node (or fifo). See mknod(2).
532 659
533The only (POSIX-) portable way of calling this function is: 660The only (POSIX-) portable way of calling this function is:
534 661
535 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 662 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
536 663
664See C<aio_stat> for info about some potentially helpful extra constants
665and functions.
537 666
538=item aio_link $srcpath, $dstpath, $callback->($status) 667=item aio_link $srcpath, $dstpath, $callback->($status)
539 668
540Asynchronously create a new link to the existing object at C<$srcpath> at 669Asynchronously create a new link to the existing object at C<$srcpath> at
541the path C<$dstpath> and call the callback with the result code. 670the path C<$dstpath> and call the callback with the result code.
545 674
546Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 675Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
547the path C<$dstpath> and call the callback with the result code. 676the path C<$dstpath> and call the callback with the result code.
548 677
549 678
550=item aio_readlink $path, $callback->($link) 679=item aio_readlink $pathname, $callback->($link)
551 680
552Asynchronously read the symlink specified by C<$path> and pass it to 681Asynchronously read the symlink specified by C<$path> and pass it to
553the callback. If an error occurs, nothing or undef gets passed to the 682the callback. If an error occurs, nothing or undef gets passed to the
554callback. 683callback.
555 684
556 685
686=item aio_realpath $pathname, $callback->($path)
687
688Asynchronously make the path absolute and resolve any symlinks in
689C<$path>. The resulting path only consists of directories (Same as
690L<Cwd::realpath>).
691
692This request can be used to get the absolute path of the current working
693directory by passing it a path of F<.> (a single dot).
694
695
557=item aio_rename $srcpath, $dstpath, $callback->($status) 696=item aio_rename $srcpath, $dstpath, $callback->($status)
558 697
559Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 698Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
560rename(2) and call the callback with the result code. 699rename(2) and call the callback with the result code.
561 700
577 716
578Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 717Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
579directory (i.e. opendir + readdir + closedir). The entries will not be 718directory (i.e. opendir + readdir + closedir). The entries will not be
580sorted, and will B<NOT> include the C<.> and C<..> entries. 719sorted, and will B<NOT> include the C<.> and C<..> entries.
581 720
582The callback a single argument which is either C<undef> or an array-ref 721The callback is passed a single argument which is either C<undef> or an
583with the filenames. 722array-ref with the filenames.
584 723
585 724
725=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
726
727Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
728tune behaviour and output format. In case of an error, C<$entries> will be
729C<undef>.
730
731The flags are a combination of the following constants, ORed together (the
732flags will also be passed to the callback, possibly modified):
733
734=over 4
735
736=item IO::AIO::READDIR_DENTS
737
738When this flag is off, then the callback gets an arrayref consisting of
739names only (as with C<aio_readdir>), otherwise it gets an arrayref with
740C<[$name, $type, $inode]> arrayrefs, each describing a single directory
741entry in more detail.
742
743C<$name> is the name of the entry.
744
745C<$type> is one of the C<IO::AIO::DT_xxx> constants:
746
747C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
748C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
749C<IO::AIO::DT_WHT>.
750
751C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
752know, you have to run stat yourself. Also, for speed reasons, the C<$type>
753scalars are read-only: you can not modify them.
754
755C<$inode> is the inode number (which might not be exact on systems with 64
756bit inode numbers and 32 bit perls). This field has unspecified content on
757systems that do not deliver the inode information.
758
759=item IO::AIO::READDIR_DIRS_FIRST
760
761When this flag is set, then the names will be returned in an order where
762likely directories come first, in optimal stat order. This is useful when
763you need to quickly find directories, or you want to find all directories
764while avoiding to stat() each entry.
765
766If the system returns type information in readdir, then this is used
767to find directories directly. Otherwise, likely directories are names
768beginning with ".", or otherwise names with no dots, of which names with
769short names are tried first.
770
771=item IO::AIO::READDIR_STAT_ORDER
772
773When this flag is set, then the names will be returned in an order
774suitable for stat()'ing each one. That is, when you plan to stat()
775all files in the given directory, then the returned order will likely
776be fastest.
777
778If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
779the likely dirs come first, resulting in a less optimal stat order.
780
781=item IO::AIO::READDIR_FOUND_UNKNOWN
782
783This flag should not be set when calling C<aio_readdirx>. Instead, it
784is being set by C<aio_readdirx>, when any of the C<$type>'s found were
785C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
786C<$type>'s are known, which can be used to speed up some algorithms.
787
788=back
789
790
586=item aio_load $path, $data, $callback->($status) 791=item aio_load $pathname, $data, $callback->($status)
587 792
588This is a composite request that tries to fully load the given file into 793This is a composite request that tries to fully load the given file into
589memory. Status is the same as with aio_read. 794memory. Status is the same as with aio_read.
590 795
591=cut 796=cut
592 797
593sub aio_load($$;$) { 798sub aio_load($$;$) {
594 aio_block {
595 my ($path, undef, $cb) = @_; 799 my ($path, undef, $cb) = @_;
596 my $data = \$_[1]; 800 my $data = \$_[1];
597 801
598 my $pri = aioreq_pri; 802 my $pri = aioreq_pri;
599 my $grp = aio_group $cb; 803 my $grp = aio_group $cb;
804
805 aioreq_pri $pri;
806 add $grp aio_open $path, O_RDONLY, 0, sub {
807 my $fh = shift
808 or return $grp->result (-1);
600 809
601 aioreq_pri $pri; 810 aioreq_pri $pri;
602 add $grp aio_open $path, O_RDONLY, 0, sub {
603 my $fh = shift
604 or return $grp->result (-1);
605
606 aioreq_pri $pri;
607 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub { 811 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
608 $grp->result ($_[0]); 812 $grp->result ($_[0]);
609 };
610 }; 813 };
611
612 $grp
613 } 814 };
815
816 $grp
614} 817}
615 818
616=item aio_copy $srcpath, $dstpath, $callback->($status) 819=item aio_copy $srcpath, $dstpath, $callback->($status)
617 820
618Try to copy the I<file> (directories not supported as either source or 821Try to copy the I<file> (directories not supported as either source or
619destination) from C<$srcpath> to C<$dstpath> and call the callback with 822destination) from C<$srcpath> to C<$dstpath> and call the callback with
620the C<0> (error) or C<-1> ok. 823a status of C<0> (ok) or C<-1> (error, see C<$!>).
621 824
622This is a composite request that it creates the destination file with 825This is a composite request that creates the destination file with
623mode 0200 and copies the contents of the source file into it using 826mode 0200 and copies the contents of the source file into it using
624C<aio_sendfile>, followed by restoring atime, mtime, access mode and 827C<aio_sendfile>, followed by restoring atime, mtime, access mode and
625uid/gid, in that order. 828uid/gid, in that order.
626 829
627If an error occurs, the partial destination file will be unlinked, if 830If an error occurs, the partial destination file will be unlinked, if
629errors are being ignored. 832errors are being ignored.
630 833
631=cut 834=cut
632 835
633sub aio_copy($$;$) { 836sub aio_copy($$;$) {
634 aio_block {
635 my ($src, $dst, $cb) = @_; 837 my ($src, $dst, $cb) = @_;
636 838
637 my $pri = aioreq_pri; 839 my $pri = aioreq_pri;
638 my $grp = aio_group $cb; 840 my $grp = aio_group $cb;
639 841
640 aioreq_pri $pri; 842 aioreq_pri $pri;
641 add $grp aio_open $src, O_RDONLY, 0, sub { 843 add $grp aio_open $src, O_RDONLY, 0, sub {
642 if (my $src_fh = $_[0]) { 844 if (my $src_fh = $_[0]) {
643 my @stat = stat $src_fh; 845 my @stat = stat $src_fh; # hmm, might block over nfs?
644 846
645 aioreq_pri $pri; 847 aioreq_pri $pri;
646 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 848 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
647 if (my $dst_fh = $_[0]) { 849 if (my $dst_fh = $_[0]) {
648 aioreq_pri $pri; 850 aioreq_pri $pri;
649 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 851 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
650 if ($_[0] == $stat[7]) { 852 if ($_[0] == $stat[7]) {
651 $grp->result (0); 853 $grp->result (0);
652 close $src_fh; 854 close $src_fh;
653 855
654 # those should not normally block. should. should. 856 my $ch = sub {
655 utime $stat[8], $stat[9], $dst;
656 chmod $stat[2] & 07777, $dst_fh;
657 chown $stat[4], $stat[5], $dst_fh;
658
659 aioreq_pri $pri; 857 aioreq_pri $pri;
858 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
859 aioreq_pri $pri;
860 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
861 aioreq_pri $pri;
660 add $grp aio_close $dst_fh; 862 add $grp aio_close $dst_fh;
661 } else { 863 }
662 $grp->result (-1);
663 close $src_fh;
664 close $dst_fh;
665
666 aioreq $pri; 864 };
667 add $grp aio_unlink $dst;
668 } 865 };
866
867 aioreq_pri $pri;
868 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
869 if ($_[0] < 0 && $! == ENOSYS) {
870 aioreq_pri $pri;
871 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
872 } else {
873 $ch->();
874 }
875 };
876 } else {
877 $grp->result (-1);
878 close $src_fh;
879 close $dst_fh;
880
881 aioreq $pri;
882 add $grp aio_unlink $dst;
669 }; 883 }
670 } else {
671 $grp->result (-1);
672 } 884 };
885 } else {
886 $grp->result (-1);
673 }, 887 }
674
675 } else {
676 $grp->result (-1);
677 } 888 },
889
890 } else {
891 $grp->result (-1);
678 }; 892 }
679
680 $grp
681 } 893 };
894
895 $grp
682} 896}
683 897
684=item aio_move $srcpath, $dstpath, $callback->($status) 898=item aio_move $srcpath, $dstpath, $callback->($status)
685 899
686Try to move the I<file> (directories not supported as either source or 900Try to move the I<file> (directories not supported as either source or
687destination) from C<$srcpath> to C<$dstpath> and call the callback with 901destination) from C<$srcpath> to C<$dstpath> and call the callback with
688the C<0> (error) or C<-1> ok. 902a status of C<0> (ok) or C<-1> (error, see C<$!>).
689 903
690This is a composite request that tries to rename(2) the file first. If 904This is a composite request that tries to rename(2) the file first; if
691rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 905rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
692that is successful, unlinking the C<$srcpath>. 906that is successful, unlinks the C<$srcpath>.
693 907
694=cut 908=cut
695 909
696sub aio_move($$;$) { 910sub aio_move($$;$) {
697 aio_block {
698 my ($src, $dst, $cb) = @_; 911 my ($src, $dst, $cb) = @_;
699 912
700 my $pri = aioreq_pri; 913 my $pri = aioreq_pri;
701 my $grp = aio_group $cb; 914 my $grp = aio_group $cb;
702 915
703 aioreq_pri $pri; 916 aioreq_pri $pri;
704 add $grp aio_rename $src, $dst, sub { 917 add $grp aio_rename $src, $dst, sub {
705 if ($_[0] && $! == EXDEV) { 918 if ($_[0] && $! == EXDEV) {
706 aioreq_pri $pri; 919 aioreq_pri $pri;
707 add $grp aio_copy $src, $dst, sub { 920 add $grp aio_copy $src, $dst, sub {
708 $grp->result ($_[0]);
709
710 if (!$_[0]) {
711 aioreq_pri $pri;
712 add $grp aio_unlink $src;
713 }
714 };
715 } else {
716 $grp->result ($_[0]); 921 $grp->result ($_[0]);
922
923 unless ($_[0]) {
924 aioreq_pri $pri;
925 add $grp aio_unlink $src;
926 }
717 } 927 };
928 } else {
929 $grp->result ($_[0]);
718 }; 930 }
719
720 $grp
721 } 931 };
932
933 $grp
722} 934}
723 935
724=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 936=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
725 937
726Scans a directory (similar to C<aio_readdir>) but additionally tries to 938Scans a directory (similar to C<aio_readdir>) but additionally tries to
727efficiently separate the entries of directory C<$path> into two sets of 939efficiently separate the entries of directory C<$path> into two sets of
728names, directories you can recurse into (directories), and ones you cannot 940names, directories you can recurse into (directories), and ones you cannot
729recurse into (everything else, including symlinks to directories). 941recurse into (everything else, including symlinks to directories).
746 958
747Implementation notes. 959Implementation notes.
748 960
749The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 961The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
750 962
963If readdir returns file type information, then this is used directly to
964find directories.
965
751After reading the directory, the modification time, size etc. of the 966Otherwise, after reading the directory, the modification time, size etc.
752directory before and after the readdir is checked, and if they match (and 967of the directory before and after the readdir is checked, and if they
753isn't the current time), the link count will be used to decide how many 968match (and isn't the current time), the link count will be used to decide
754entries are directories (if >= 2). Otherwise, no knowledge of the number 969how many entries are directories (if >= 2). Otherwise, no knowledge of the
755of subdirectories will be assumed. 970number of subdirectories will be assumed.
756 971
757Then entries will be sorted into likely directories (everything without 972Then entries will be sorted into likely directories a non-initial dot
758a non-initial dot currently) and likely non-directories (everything 973currently) and likely non-directories (see C<aio_readdirx>). Then every
759else). Then every entry plus an appended C</.> will be C<stat>'ed, 974entry plus an appended C</.> will be C<stat>'ed, likely directories first,
760likely directories first. If that succeeds, it assumes that the entry 975in order of their inode numbers. If that succeeds, it assumes that the
761is a directory or a symlink to directory (which will be checked 976entry is a directory or a symlink to directory (which will be checked
762seperately). This is often faster than stat'ing the entry itself because 977separately). This is often faster than stat'ing the entry itself because
763filesystems might detect the type of the entry without reading the inode 978filesystems might detect the type of the entry without reading the inode
764data (e.g. ext2fs filetype feature). 979data (e.g. ext2fs filetype feature), even on systems that cannot return
980the filetype information on readdir.
765 981
766If the known number of directories (link count - 2) has been reached, the 982If the known number of directories (link count - 2) has been reached, the
767rest of the entries is assumed to be non-directories. 983rest of the entries is assumed to be non-directories.
768 984
769This only works with certainty on POSIX (= UNIX) filesystems, which 985This only works with certainty on POSIX (= UNIX) filesystems, which
774directory counting heuristic. 990directory counting heuristic.
775 991
776=cut 992=cut
777 993
778sub aio_scandir($$;$) { 994sub aio_scandir($$;$) {
779 aio_block {
780 my ($path, $maxreq, $cb) = @_; 995 my ($path, $maxreq, $cb) = @_;
781 996
782 my $pri = aioreq_pri; 997 my $pri = aioreq_pri;
783 998
784 my $grp = aio_group $cb; 999 my $grp = aio_group $cb;
785 1000
786 $maxreq = 4 if $maxreq <= 0; 1001 $maxreq = 4 if $maxreq <= 0;
1002
1003 # get a wd object
1004 aioreq_pri $pri;
1005 add $grp aio_wd $path, sub {
1006 $_[0]
1007 or return $grp->result ();
1008
1009 my $wd = [shift, "."];
787 1010
788 # stat once 1011 # stat once
789 aioreq_pri $pri; 1012 aioreq_pri $pri;
790 add $grp aio_stat $path, sub { 1013 add $grp aio_stat $wd, sub {
791 return $grp->result () if $_[0]; 1014 return $grp->result () if $_[0];
792 my $now = time; 1015 my $now = time;
793 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 1016 my $hash1 = join ":", (stat _)[0,1,3,7,9];
794 1017
795 # read the directory entries 1018 # read the directory entries
796 aioreq_pri $pri; 1019 aioreq_pri $pri;
797 add $grp aio_readdir $path, sub { 1020 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
798 my $entries = shift 1021 my $entries = shift
799 or return $grp->result (); 1022 or return $grp->result ();
800 1023
801 # stat the dir another time 1024 # stat the dir another time
802 aioreq_pri $pri; 1025 aioreq_pri $pri;
803 add $grp aio_stat $path, sub { 1026 add $grp aio_stat $wd, sub {
804 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1027 my $hash2 = join ":", (stat _)[0,1,3,7,9];
805 1028
806 my $ndirs; 1029 my $ndirs;
807 1030
808 # take the slow route if anything looks fishy 1031 # take the slow route if anything looks fishy
809 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1032 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
810 $ndirs = -1; 1033 $ndirs = -1;
811 } else { 1034 } else {
812 # if nlink == 2, we are finished 1035 # if nlink == 2, we are finished
813 # on non-posix-fs's, we rely on nlink < 2 1036 # for non-posix-fs's, we rely on nlink < 2
814 $ndirs = (stat _)[3] - 2 1037 $ndirs = (stat _)[3] - 2
815 or return $grp->result ([], $entries); 1038 or return $grp->result ([], $entries);
816 } 1039 }
817 1040
818 # sort into likely dirs and likely nondirs
819 # dirs == files without ".", short entries first
820 $entries = [map $_->[0],
821 sort { $b->[1] cmp $a->[1] }
822 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
823 @$entries];
824
825 my (@dirs, @nondirs); 1041 my (@dirs, @nondirs);
826 1042
827 my $statgrp = add $grp aio_group sub { 1043 my $statgrp = add $grp aio_group sub {
828 $grp->result (\@dirs, \@nondirs); 1044 $grp->result (\@dirs, \@nondirs);
829 }; 1045 };
830 1046
831 limit $statgrp $maxreq; 1047 limit $statgrp $maxreq;
832 feed $statgrp sub { 1048 feed $statgrp sub {
833 return unless @$entries; 1049 return unless @$entries;
834 my $entry = pop @$entries; 1050 my $entry = shift @$entries;
835 1051
836 aioreq_pri $pri; 1052 aioreq_pri $pri;
1053 $wd->[1] = "$entry/.";
837 add $statgrp aio_stat "$path/$entry/.", sub { 1054 add $statgrp aio_stat $wd, sub {
838 if ($_[0] < 0) { 1055 if ($_[0] < 0) {
839 push @nondirs, $entry; 1056 push @nondirs, $entry;
840 } else { 1057 } else {
841 # need to check for real directory 1058 # need to check for real directory
842 aioreq_pri $pri; 1059 aioreq_pri $pri;
1060 $wd->[1] = $entry;
843 add $statgrp aio_lstat "$path/$entry", sub { 1061 add $statgrp aio_lstat $wd, sub {
844 if (-d _) { 1062 if (-d _) {
845 push @dirs, $entry; 1063 push @dirs, $entry;
846 1064
847 unless (--$ndirs) { 1065 unless (--$ndirs) {
848 push @nondirs, @$entries; 1066 push @nondirs, @$entries;
856 }; 1074 };
857 }; 1075 };
858 }; 1076 };
859 }; 1077 };
860 }; 1078 };
861
862 $grp
863 } 1079 };
1080
1081 $grp
864} 1082}
865 1083
866=item aio_rmtree $path, $callback->($status) 1084=item aio_rmtree $pathname, $callback->($status)
867 1085
868Delete a directory tree starting (and including) C<$path>, return the 1086Delete a directory tree starting (and including) C<$path>, return the
869status of the final C<rmdir> only. This is a composite request that 1087status of the final C<rmdir> only. This is a composite request that
870uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1088uses C<aio_scandir> to recurse into and rmdir directories, and unlink
871everything else. 1089everything else.
872 1090
873=cut 1091=cut
874 1092
875sub aio_rmtree; 1093sub aio_rmtree;
876sub aio_rmtree($;$) { 1094sub aio_rmtree($;$) {
877 aio_block {
878 my ($path, $cb) = @_; 1095 my ($path, $cb) = @_;
879 1096
880 my $pri = aioreq_pri; 1097 my $pri = aioreq_pri;
881 my $grp = aio_group $cb; 1098 my $grp = aio_group $cb;
882 1099
883 aioreq_pri $pri; 1100 aioreq_pri $pri;
884 add $grp aio_scandir $path, 0, sub { 1101 add $grp aio_scandir $path, 0, sub {
885 my ($dirs, $nondirs) = @_; 1102 my ($dirs, $nondirs) = @_;
886 1103
887 my $dirgrp = aio_group sub { 1104 my $dirgrp = aio_group sub {
888 add $grp aio_rmdir $path, sub { 1105 add $grp aio_rmdir $path, sub {
889 $grp->result ($_[0]); 1106 $grp->result ($_[0]);
890 };
891 }; 1107 };
892
893 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
894 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
895
896 add $grp $dirgrp;
897 }; 1108 };
898 1109
899 $grp 1110 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
1111 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
1112
1113 add $grp $dirgrp;
900 } 1114 };
1115
1116 $grp
901} 1117}
902 1118
903=item aio_sync $callback->($status) 1119=item aio_sync $callback->($status)
904 1120
905Asynchronously call sync and call the callback when finished. 1121Asynchronously call sync and call the callback when finished.
915callback with the fdatasync result code. 1131callback with the fdatasync result code.
916 1132
917If this call isn't available because your OS lacks it or it couldn't be 1133If this call isn't available because your OS lacks it or it couldn't be
918detected, it will be emulated by calling C<fsync> instead. 1134detected, it will be emulated by calling C<fsync> instead.
919 1135
1136=item aio_syncfs $fh, $callback->($status)
1137
1138Asynchronously call the syncfs syscall to sync the filesystem associated
1139to the given filehandle and call the callback with the syncfs result
1140code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1141errno to C<ENOSYS> nevertheless.
1142
1143=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1144
1145Sync the data portion of the file specified by C<$offset> and C<$length>
1146to disk (but NOT the metadata), by calling the Linux-specific
1147sync_file_range call. If sync_file_range is not available or it returns
1148ENOSYS, then fdatasync or fsync is being substituted.
1149
1150C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1151C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1152C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1153manpage for details.
1154
920=item aio_pathsync $path, $callback->($status) 1155=item aio_pathsync $pathname, $callback->($status)
921 1156
922This request tries to open, fsync and close the given path. This is a 1157This request tries to open, fsync and close the given path. This is a
923composite request intended tosync directories after directory operations 1158composite request intended to sync directories after directory operations
924(E.g. rename). This might not work on all operating systems or have any 1159(E.g. rename). This might not work on all operating systems or have any
925specific effect, but usually it makes sure that directory changes get 1160specific effect, but usually it makes sure that directory changes get
926written to disc. It works for anything that can be opened for read-only, 1161written to disc. It works for anything that can be opened for read-only,
927not just directories. 1162not just directories.
928 1163
1164Future versions of this function might fall back to other methods when
1165C<fsync> on the directory fails (such as calling C<sync>).
1166
929Passes C<0> when everything went ok, and C<-1> on error. 1167Passes C<0> when everything went ok, and C<-1> on error.
930 1168
931=cut 1169=cut
932 1170
933sub aio_pathsync($;$) { 1171sub aio_pathsync($;$) {
934 aio_block {
935 my ($path, $cb) = @_; 1172 my ($path, $cb) = @_;
936 1173
937 my $pri = aioreq_pri; 1174 my $pri = aioreq_pri;
938 my $grp = aio_group $cb; 1175 my $grp = aio_group $cb;
939 1176
940 aioreq_pri $pri; 1177 aioreq_pri $pri;
941 add $grp aio_open $path, O_RDONLY, 0, sub { 1178 add $grp aio_open $path, O_RDONLY, 0, sub {
942 my ($fh) = @_; 1179 my ($fh) = @_;
943 if ($fh) { 1180 if ($fh) {
1181 aioreq_pri $pri;
1182 add $grp aio_fsync $fh, sub {
1183 $grp->result ($_[0]);
1184
944 aioreq_pri $pri; 1185 aioreq_pri $pri;
945 add $grp aio_fsync $fh, sub {
946 $grp->result ($_[0]);
947
948 aioreq_pri $pri;
949 add $grp aio_close $fh; 1186 add $grp aio_close $fh;
950 };
951 } else {
952 $grp->result (-1);
953 } 1187 };
1188 } else {
1189 $grp->result (-1);
954 }; 1190 }
955
956 $grp
957 } 1191 };
1192
1193 $grp
958} 1194}
1195
1196=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1197
1198This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1199scalars (see the C<IO::AIO::mmap> function, although it also works on data
1200scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1201scalar must only be modified in-place while an aio operation is pending on
1202it).
1203
1204It calls the C<msync> function of your OS, if available, with the memory
1205area starting at C<$offset> in the string and ending C<$length> bytes
1206later. If C<$length> is negative, counts from the end, and if C<$length>
1207is C<undef>, then it goes till the end of the string. The flags can be
1208a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1209C<IO::AIO::MS_SYNC>.
1210
1211=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1212
1213This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1214scalars.
1215
1216It touches (reads or writes) all memory pages in the specified
1217range inside the scalar. All caveats and parameters are the same
1218as for C<aio_msync>, above, except for flags, which must be either
1219C<0> (which reads all pages and ensures they are instantiated) or
1220C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1221writing an octet from it, which dirties the page).
1222
1223=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1224
1225This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1226scalars.
1227
1228It reads in all the pages of the underlying storage into memory (if any)
1229and locks them, so they are not getting swapped/paged out or removed.
1230
1231If C<$length> is undefined, then the scalar will be locked till the end.
1232
1233On systems that do not implement C<mlock>, this function returns C<-1>
1234and sets errno to C<ENOSYS>.
1235
1236Note that the corresponding C<munlock> is synchronous and is
1237documented under L<MISCELLANEOUS FUNCTIONS>.
1238
1239Example: open a file, mmap and mlock it - both will be undone when
1240C<$data> gets destroyed.
1241
1242 open my $fh, "<", $path or die "$path: $!";
1243 my $data;
1244 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1245 aio_mlock $data; # mlock in background
1246
1247=item aio_mlockall $flags, $callback->($status)
1248
1249Calls the C<mlockall> function with the given C<$flags> (a combination of
1250C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1251
1252On systems that do not implement C<mlockall>, this function returns C<-1>
1253and sets errno to C<ENOSYS>.
1254
1255Note that the corresponding C<munlockall> is synchronous and is
1256documented under L<MISCELLANEOUS FUNCTIONS>.
1257
1258Example: asynchronously lock all current and future pages into memory.
1259
1260 aio_mlockall IO::AIO::MCL_FUTURE;
1261
1262=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1263
1264Queries the extents of the given file (by calling the Linux FIEMAP ioctl,
1265see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If the
1266C<ioctl> is not available on your OS, then this rquiest will fail with
1267C<ENOSYS>.
1268
1269C<$start> is the starting offset to query extents for, C<$length> is the
1270size of the range to query - if it is C<undef>, then the whole file will
1271be queried.
1272
1273C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1274C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1275exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1276the data portion.
1277
1278C<$count> is the maximum number of extent records to return. If it is
1279C<undef>, then IO::AIO queries all extents of the file. As a very special
1280case, if it is C<0>, then the callback receives the number of extents
1281instead of the extents themselves.
1282
1283If an error occurs, the callback receives no arguments. The special
1284C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1285
1286Otherwise, the callback receives an array reference with extent
1287structures. Each extent structure is an array reference itself, with the
1288following members:
1289
1290 [$logical, $physical, $length, $flags]
1291
1292Flags is any combination of the following flag values (typically either C<0>
1293or C<IO::AIO::FIEMAP_EXTENT_LAST>):
1294
1295C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1296C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1297C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1298C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1299C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1300C<IO::AIO::FIEMAP_EXTENT_SHARED>.
959 1301
960=item aio_group $callback->(...) 1302=item aio_group $callback->(...)
961 1303
962This is a very special aio request: Instead of doing something, it is a 1304This is a very special aio request: Instead of doing something, it is a
963container for other aio requests, which is useful if you want to bundle 1305container for other aio requests, which is useful if you want to bundle
1001immense (it blocks a thread for a long time) so do not use this function 1343immense (it blocks a thread for a long time) so do not use this function
1002except to put your application under artificial I/O pressure. 1344except to put your application under artificial I/O pressure.
1003 1345
1004=back 1346=back
1005 1347
1348
1349=head2 IO::AIO::WD - multiple working directories
1350
1351Your process only has one current working directory, which is used by all
1352threads. This makes it hard to use relative paths (some other component
1353could call C<chdir> at any time, and it is hard to control when the path
1354will be used by IO::AIO).
1355
1356One solution for this is to always use absolute paths. This usually works,
1357but can be quite slow (the kernel has to walk the whole path on every
1358access), and can also be a hassle to implement.
1359
1360Newer POSIX systems have a number of functions (openat, fdopendir,
1361futimensat and so on) that make it possible to specify working directories
1362per operation.
1363
1364For portability, and because the clowns who "designed", or shall I write,
1365perpetrated this new interface were obviously half-drunk, this abstraction
1366cannot be perfect, though.
1367
1368IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1369object. This object stores the canonicalised, absolute version of the
1370path, and on systems that allow it, also a directory file descriptor.
1371
1372Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1373or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1374object and a pathname instead (or the IO::AIO::WD object alone, which
1375gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1376IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1377to that IO::AIO::WD object.
1378
1379For example, to get a wd object for F</etc> and then stat F<passwd>
1380inside, you would write:
1381
1382 aio_wd "/etc", sub {
1383 my $etcdir = shift;
1384
1385 # although $etcdir can be undef on error, there is generally no reason
1386 # to check for errors here, as aio_stat will fail with ENOENT
1387 # when $etcdir is undef.
1388
1389 aio_stat [$etcdir, "passwd"], sub {
1390 # yay
1391 };
1392 };
1393
1394That C<aio_wd> is a request and not a normal function shows that creating
1395an IO::AIO::WD object is itself a potentially blocking operation, which is
1396why it is done asynchronously.
1397
1398To stat the directory obtained with C<aio_wd> above, one could write
1399either of the following three request calls:
1400
1401 aio_lstat "/etc" , sub { ... # pathname as normal string
1402 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1403 aio_lstat $wd , sub { ... # shorthand for the previous
1404
1405As with normal pathnames, IO::AIO keeps a copy of the working directory
1406object and the pathname string, so you could write the following without
1407causing any issues due to C<$path> getting reused:
1408
1409 my $path = [$wd, undef];
1410
1411 for my $name (qw(abc def ghi)) {
1412 $path->[1] = $name;
1413 aio_stat $path, sub {
1414 # ...
1415 };
1416 }
1417
1418There are some caveats: when directories get renamed (or deleted), the
1419pathname string doesn't change, so will point to the new directory (or
1420nowhere at all), while the directory fd, if available on the system,
1421will still point to the original directory. Most functions accepting a
1422pathname will use the directory fd on newer systems, and the string on
1423older systems. Some functions (such as realpath) will always rely on the
1424string form of the pathname.
1425
1426So this fucntionality is mainly useful to get some protection against
1427C<chdir>, to easily get an absolute path out of a relative path for future
1428reference, and to speed up doing many operations in the same directory
1429(e.g. when stat'ing all files in a directory).
1430
1431The following functions implement this working directory abstraction:
1432
1433=over 4
1434
1435=item aio_wd $pathname, $callback->($wd)
1436
1437Asynchonously canonicalise the given pathname and convert it to an
1438IO::AIO::WD object representing it. If possible and supported on the
1439system, also open a directory fd to speed up pathname resolution relative
1440to this working directory.
1441
1442If something goes wrong, then C<undef> is passwd to the callback instead
1443of a working directory object and C<$!> is set appropriately. Since
1444passing C<undef> as working directory component of a pathname fails the
1445request with C<ENOENT>, there is often no need for error checking in the
1446C<aio_wd> callback, as future requests using the value will fail in the
1447expected way.
1448
1449If this call isn't available because your OS lacks it or it couldn't be
1450detected, it will be emulated by calling C<fsync> instead.
1451
1452=item IO::AIO::CWD
1453
1454This is a compiletime constant (object) that represents the process
1455current working directory.
1456
1457Specifying this object as working directory object for a pathname is as
1458if the pathname would be specified directly, without a directory object,
1459e.g., these calls are functionally identical:
1460
1461 aio_stat "somefile", sub { ... };
1462 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1463
1464=back
1465
1466
1006=head2 IO::AIO::REQ CLASS 1467=head2 IO::AIO::REQ CLASS
1007 1468
1008All non-aggregate C<aio_*> functions return an object of this class when 1469All non-aggregate C<aio_*> functions return an object of this class when
1009called in non-void context. 1470called in non-void context.
1010 1471
1013=item cancel $req 1474=item cancel $req
1014 1475
1015Cancels the request, if possible. Has the effect of skipping execution 1476Cancels the request, if possible. Has the effect of skipping execution
1016when entering the B<execute> state and skipping calling the callback when 1477when entering the B<execute> state and skipping calling the callback when
1017entering the the B<result> state, but will leave the request otherwise 1478entering the the B<result> state, but will leave the request otherwise
1018untouched. That means that requests that currently execute will not be 1479untouched (with the exception of readdir). That means that requests that
1019stopped and resources held by the request will not be freed prematurely. 1480currently execute will not be stopped and resources held by the request
1481will not be freed prematurely.
1020 1482
1021=item cb $req $callback->(...) 1483=item cb $req $callback->(...)
1022 1484
1023Replace (or simply set) the callback registered to the request. 1485Replace (or simply set) the callback registered to the request.
1024 1486
1075Their lifetime, simplified, looks like this: when they are empty, they 1537Their lifetime, simplified, looks like this: when they are empty, they
1076will finish very quickly. If they contain only requests that are in the 1538will finish very quickly. If they contain only requests that are in the
1077C<done> state, they will also finish. Otherwise they will continue to 1539C<done> state, they will also finish. Otherwise they will continue to
1078exist. 1540exist.
1079 1541
1080That means after creating a group you have some time to add requests. And 1542That means after creating a group you have some time to add requests
1081in the callbacks of those requests, you can add further requests to the 1543(precisely before the callback has been invoked, which is only done within
1082group. And only when all those requests have finished will the the group 1544the C<poll_cb>). And in the callbacks of those requests, you can add
1083itself finish. 1545further requests to the group. And only when all those requests have
1546finished will the the group itself finish.
1084 1547
1085=over 4 1548=over 4
1086 1549
1087=item add $grp ... 1550=item add $grp ...
1088 1551
1096 1559
1097=item $grp->cancel_subs 1560=item $grp->cancel_subs
1098 1561
1099Cancel all subrequests and clears any feeder, but not the group request 1562Cancel all subrequests and clears any feeder, but not the group request
1100itself. Useful when you queued a lot of events but got a result early. 1563itself. Useful when you queued a lot of events but got a result early.
1564
1565The group request will finish normally (you cannot add requests to the
1566group).
1101 1567
1102=item $grp->result (...) 1568=item $grp->result (...)
1103 1569
1104Set the result value(s) that will be passed to the group callback when all 1570Set the result value(s) that will be passed to the group callback when all
1105subrequests have finished and set the groups errno to the current value 1571subrequests have finished and set the groups errno to the current value
1121=item feed $grp $callback->($grp) 1587=item feed $grp $callback->($grp)
1122 1588
1123Sets a feeder/generator on this group: every group can have an attached 1589Sets a feeder/generator on this group: every group can have an attached
1124generator that generates requests if idle. The idea behind this is that, 1590generator that generates requests if idle. The idea behind this is that,
1125although you could just queue as many requests as you want in a group, 1591although you could just queue as many requests as you want in a group,
1126this might starve other requests for a potentially long time. For 1592this might starve other requests for a potentially long time. For example,
1127example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1593C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1128requests, delaying any later requests for a long time. 1594requests, delaying any later requests for a long time.
1129 1595
1130To avoid this, and allow incremental generation of requests, you can 1596To avoid this, and allow incremental generation of requests, you can
1131instead a group and set a feeder on it that generates those requests. The 1597instead a group and set a feeder on it that generates those requests. The
1132feed callback will be called whenever there are few enough (see C<limit>, 1598feed callback will be called whenever there are few enough (see C<limit>,
1137not impose any limits). 1603not impose any limits).
1138 1604
1139If the feed does not queue more requests when called, it will be 1605If the feed does not queue more requests when called, it will be
1140automatically removed from the group. 1606automatically removed from the group.
1141 1607
1142If the feed limit is C<0>, it will be set to C<2> automatically. 1608If the feed limit is C<0> when this method is called, it will be set to
1609C<2> automatically.
1143 1610
1144Example: 1611Example:
1145 1612
1146 # stat all files in @files, but only ever use four aio requests concurrently: 1613 # stat all files in @files, but only ever use four aio requests concurrently:
1147 1614
1159Sets the feeder limit for the group: The feeder will be called whenever 1626Sets the feeder limit for the group: The feeder will be called whenever
1160the group contains less than this many requests. 1627the group contains less than this many requests.
1161 1628
1162Setting the limit to C<0> will pause the feeding process. 1629Setting the limit to C<0> will pause the feeding process.
1163 1630
1631The default value for the limit is C<0>, but note that setting a feeder
1632automatically bumps it up to C<2>.
1633
1164=back 1634=back
1165 1635
1166=head2 SUPPORT FUNCTIONS 1636=head2 SUPPORT FUNCTIONS
1167 1637
1168=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 1638=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1170=over 4 1640=over 4
1171 1641
1172=item $fileno = IO::AIO::poll_fileno 1642=item $fileno = IO::AIO::poll_fileno
1173 1643
1174Return the I<request result pipe file descriptor>. This filehandle must be 1644Return the I<request result pipe file descriptor>. This filehandle must be
1175polled for reading by some mechanism outside this module (e.g. Event or 1645polled for reading by some mechanism outside this module (e.g. EV, Glib,
1176select, see below or the SYNOPSIS). If the pipe becomes readable you have 1646select and so on, see below or the SYNOPSIS). If the pipe becomes readable
1177to call C<poll_cb> to check the results. 1647you have to call C<poll_cb> to check the results.
1178 1648
1179See C<poll_cb> for an example. 1649See C<poll_cb> for an example.
1180 1650
1181=item IO::AIO::poll_cb 1651=item IO::AIO::poll_cb
1182 1652
1183Process some outstanding events on the result pipe. You have to call this 1653Process some outstanding events on the result pipe. You have to call
1184regularly. Returns the number of events processed. Returns immediately 1654this regularly. Returns C<0> if all events could be processed (or there
1185when no events are outstanding. The amount of events processed depends on 1655were no events to process), or C<-1> if it returned earlier for whatever
1186the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>. 1656reason. Returns immediately when no events are outstanding. The amount of
1657events processed depends on the settings of C<IO::AIO::max_poll_req> and
1658C<IO::AIO::max_poll_time>.
1187 1659
1188If not all requests were processed for whatever reason, the filehandle 1660If not all requests were processed for whatever reason, the filehandle
1189will still be ready when C<poll_cb> returns. 1661will still be ready when C<poll_cb> returns, so normally you don't have to
1662do anything special to have it called later.
1663
1664Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1665ready, it can be beneficial to call this function from loops which submit
1666a lot of requests, to make sure the results get processed when they become
1667available and not just when the loop is finished and the event loop takes
1668over again. This function returns very fast when there are no outstanding
1669requests.
1190 1670
1191Example: Install an Event watcher that automatically calls 1671Example: Install an Event watcher that automatically calls
1192IO::AIO::poll_cb with high priority: 1672IO::AIO::poll_cb with high priority (more examples can be found in the
1673SYNOPSIS section, at the top of this document):
1193 1674
1194 Event->io (fd => IO::AIO::poll_fileno, 1675 Event->io (fd => IO::AIO::poll_fileno,
1195 poll => 'r', async => 1, 1676 poll => 'r', async => 1,
1196 cb => \&IO::AIO::poll_cb); 1677 cb => \&IO::AIO::poll_cb);
1678
1679=item IO::AIO::poll_wait
1680
1681If there are any outstanding requests and none of them in the result
1682phase, wait till the result filehandle becomes ready for reading (simply
1683does a C<select> on the filehandle. This is useful if you want to
1684synchronously wait for some requests to finish).
1685
1686See C<nreqs> for an example.
1687
1688=item IO::AIO::poll
1689
1690Waits until some requests have been handled.
1691
1692Returns the number of requests processed, but is otherwise strictly
1693equivalent to:
1694
1695 IO::AIO::poll_wait, IO::AIO::poll_cb
1696
1697=item IO::AIO::flush
1698
1699Wait till all outstanding AIO requests have been handled.
1700
1701Strictly equivalent to:
1702
1703 IO::AIO::poll_wait, IO::AIO::poll_cb
1704 while IO::AIO::nreqs;
1197 1705
1198=item IO::AIO::max_poll_reqs $nreqs 1706=item IO::AIO::max_poll_reqs $nreqs
1199 1707
1200=item IO::AIO::max_poll_time $seconds 1708=item IO::AIO::max_poll_time $seconds
1201 1709
1226 # use a low priority so other tasks have priority 1734 # use a low priority so other tasks have priority
1227 Event->io (fd => IO::AIO::poll_fileno, 1735 Event->io (fd => IO::AIO::poll_fileno,
1228 poll => 'r', nice => 1, 1736 poll => 'r', nice => 1,
1229 cb => &IO::AIO::poll_cb); 1737 cb => &IO::AIO::poll_cb);
1230 1738
1231=item IO::AIO::poll_wait
1232
1233If there are any outstanding requests and none of them in the result
1234phase, wait till the result filehandle becomes ready for reading (simply
1235does a C<select> on the filehandle. This is useful if you want to
1236synchronously wait for some requests to finish).
1237
1238See C<nreqs> for an example.
1239
1240=item IO::AIO::poll
1241
1242Waits until some requests have been handled.
1243
1244Returns the number of requests processed, but is otherwise strictly
1245equivalent to:
1246
1247 IO::AIO::poll_wait, IO::AIO::poll_cb
1248
1249=item IO::AIO::flush
1250
1251Wait till all outstanding AIO requests have been handled.
1252
1253Strictly equivalent to:
1254
1255 IO::AIO::poll_wait, IO::AIO::poll_cb
1256 while IO::AIO::nreqs;
1257
1258=back 1739=back
1259 1740
1260=head3 CONTROLLING THE NUMBER OF THREADS 1741=head3 CONTROLLING THE NUMBER OF THREADS
1261 1742
1262=over 1743=over
1295 1776
1296Under normal circumstances you don't need to call this function. 1777Under normal circumstances you don't need to call this function.
1297 1778
1298=item IO::AIO::max_idle $nthreads 1779=item IO::AIO::max_idle $nthreads
1299 1780
1300Limit the number of threads (default: 4) that are allowed to idle (i.e., 1781Limit the number of threads (default: 4) that are allowed to idle
1301threads that did not get a request to process within 10 seconds). That 1782(i.e., threads that did not get a request to process within the idle
1302means if a thread becomes idle while C<$nthreads> other threads are also 1783timeout (default: 10 seconds). That means if a thread becomes idle while
1303idle, it will free its resources and exit. 1784C<$nthreads> other threads are also idle, it will free its resources and
1785exit.
1304 1786
1305This is useful when you allow a large number of threads (e.g. 100 or 1000) 1787This is useful when you allow a large number of threads (e.g. 100 or 1000)
1306to allow for extremely high load situations, but want to free resources 1788to allow for extremely high load situations, but want to free resources
1307under normal circumstances (1000 threads can easily consume 30MB of RAM). 1789under normal circumstances (1000 threads can easily consume 30MB of RAM).
1308 1790
1309The default is probably ok in most situations, especially if thread 1791The default is probably ok in most situations, especially if thread
1310creation is fast. If thread creation is very slow on your system you might 1792creation is fast. If thread creation is very slow on your system you might
1311want to use larger values. 1793want to use larger values.
1312 1794
1795=item IO::AIO::idle_timeout $seconds
1796
1797Sets the minimum idle timeout (default 10) after which worker threads are
1798allowed to exit. SEe C<IO::AIO::max_idle>.
1799
1313=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1800=item IO::AIO::max_outstanding $maxreqs
1801
1802Sets the maximum number of outstanding requests to C<$nreqs>. If
1803you do queue up more than this number of requests, the next call to
1804C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1805C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1806longer exceeded.
1807
1808In other words, this setting does not enforce a queue limit, but can be
1809used to make poll functions block if the limit is exceeded.
1314 1810
1315This is a very bad function to use in interactive programs because it 1811This is a very bad function to use in interactive programs because it
1316blocks, and a bad way to reduce concurrency because it is inexact: Better 1812blocks, and a bad way to reduce concurrency because it is inexact: Better
1317use an C<aio_group> together with a feed callback. 1813use an C<aio_group> together with a feed callback.
1318 1814
1319Sets the maximum number of outstanding requests to C<$nreqs>. If you 1815It's main use is in scripts without an event loop - when you want to stat
1320do queue up more than this number of requests, the next call to the 1816a lot of files, you can write somehting like this:
1321C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1322function will block until the limit is no longer exceeded.
1323 1817
1324The default value is very large, so there is no practical limit on the 1818 IO::AIO::max_outstanding 32;
1325number of outstanding requests.
1326 1819
1327You can still queue as many requests as you want. Therefore, 1820 for my $path (...) {
1328C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1821 aio_stat $path , ...;
1329as a stop gap to shield against fatal memory overflow (with large values). 1822 IO::AIO::poll_cb;
1823 }
1824
1825 IO::AIO::flush;
1826
1827The call to C<poll_cb> inside the loop will normally return instantly, but
1828as soon as more thna C<32> reqeusts are in-flight, it will block until
1829some requests have been handled. This keeps the loop from pushing a large
1830number of C<aio_stat> requests onto the queue.
1831
1832The default value for C<max_outstanding> is very large, so there is no
1833practical limit on the number of outstanding requests.
1330 1834
1331=back 1835=back
1332 1836
1333=head3 STATISTICAL INFORMATION 1837=head3 STATISTICAL INFORMATION
1334 1838
1354Returns the number of requests currently in the pending state (executed, 1858Returns the number of requests currently in the pending state (executed,
1355but not yet processed by poll_cb). 1859but not yet processed by poll_cb).
1356 1860
1357=back 1861=back
1358 1862
1863=head3 MISCELLANEOUS FUNCTIONS
1864
1865IO::AIO implements some functions that might be useful, but are not
1866asynchronous.
1867
1868=over 4
1869
1870=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1871
1872Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1873but is blocking (this makes most sense if you know the input data is
1874likely cached already and the output filehandle is set to non-blocking
1875operations).
1876
1877Returns the number of bytes copied, or C<-1> on error.
1878
1879=item IO::AIO::fadvise $fh, $offset, $len, $advice
1880
1881Simply calls the C<posix_fadvise> function (see its
1882manpage for details). The following advice constants are
1883available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1884C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1885C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1886
1887On systems that do not implement C<posix_fadvise>, this function returns
1888ENOSYS, otherwise the return value of C<posix_fadvise>.
1889
1890=item IO::AIO::madvise $scalar, $offset, $len, $advice
1891
1892Simply calls the C<posix_madvise> function (see its
1893manpage for details). The following advice constants are
1894available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1895C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1896
1897On systems that do not implement C<posix_madvise>, this function returns
1898ENOSYS, otherwise the return value of C<posix_madvise>.
1899
1900=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1901
1902Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1903$scalar (see its manpage for details). The following protect
1904constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1905C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1906
1907On systems that do not implement C<mprotect>, this function returns
1908ENOSYS, otherwise the return value of C<mprotect>.
1909
1910=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1911
1912Memory-maps a file (or anonymous memory range) and attaches it to the
1913given C<$scalar>, which will act like a string scalar.
1914
1915The only operations allowed on the scalar are C<substr>/C<vec> that don't
1916change the string length, and most read-only operations such as copying it
1917or searching it with regexes and so on.
1918
1919Anything else is unsafe and will, at best, result in memory leaks.
1920
1921The memory map associated with the C<$scalar> is automatically removed
1922when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or
1923C<IO::AIO::munmap> functions are called.
1924
1925This calls the C<mmap>(2) function internally. See your system's manual
1926page for details on the C<$length>, C<$prot> and C<$flags> parameters.
1927
1928The C<$length> must be larger than zero and smaller than the actual
1929filesize.
1930
1931C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
1932C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
1933
1934C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or
1935C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when
1936not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS>
1937(which is set to C<MAP_ANON> if your system only provides this
1938constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>,
1939C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or
1940C<IO::AIO::MAP_NONBLOCK>
1941
1942If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
1943
1944C<$offset> is the offset from the start of the file - it generally must be
1945a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
1946
1947Example:
1948
1949 use Digest::MD5;
1950 use IO::AIO;
1951
1952 open my $fh, "<verybigfile"
1953 or die "$!";
1954
1955 IO::AIO::mmap my $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh
1956 or die "verybigfile: $!";
1957
1958 my $fast_md5 = md5 $data;
1959
1960=item IO::AIO::munmap $scalar
1961
1962Removes a previous mmap and undefines the C<$scalar>.
1963
1964=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1965
1966Calls the C<munlock> function, undoing the effects of a previous
1967C<aio_mlock> call (see its description for details).
1968
1969=item IO::AIO::munlockall
1970
1971Calls the C<munlockall> function.
1972
1973On systems that do not implement C<munlockall>, this function returns
1974ENOSYS, otherwise the return value of C<munlockall>.
1975
1976=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
1977
1978Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
1979C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
1980should be the file offset.
1981
1982The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
1983C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
1984C<IO::AIO::SPLICE_F_GIFT>.
1985
1986See the C<splice(2)> manpage for details.
1987
1988=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
1989
1990Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
1991description for C<IO::AIO::splice> above for details.
1992
1993=back
1994
1359=cut 1995=cut
1360 1996
1361min_parallel 8; 1997min_parallel 8;
1362 1998
1363END { flush } 1999END { flush }
1364 2000
13651; 20011;
1366 2002
2003=head1 EVENT LOOP INTEGRATION
2004
2005It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
2006automatically into many event loops:
2007
2008 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
2009 use AnyEvent::AIO;
2010
2011You can also integrate IO::AIO manually into many event loops, here are
2012some examples of how to do this:
2013
2014 # EV integration
2015 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
2016
2017 # Event integration
2018 Event->io (fd => IO::AIO::poll_fileno,
2019 poll => 'r',
2020 cb => \&IO::AIO::poll_cb);
2021
2022 # Glib/Gtk2 integration
2023 add_watch Glib::IO IO::AIO::poll_fileno,
2024 in => sub { IO::AIO::poll_cb; 1 };
2025
2026 # Tk integration
2027 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
2028 readable => \&IO::AIO::poll_cb);
2029
2030 # Danga::Socket integration
2031 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
2032 \&IO::AIO::poll_cb);
2033
1367=head2 FORK BEHAVIOUR 2034=head2 FORK BEHAVIOUR
1368 2035
1369This module should do "the right thing" when the process using it forks: 2036Usage of pthreads in a program changes the semantics of fork
2037considerably. Specifically, only async-safe functions can be called after
2038fork. Perl doesn't know about this, so in general, you cannot call fork
2039with defined behaviour in perl if pthreads are involved. IO::AIO uses
2040pthreads, so this applies, but many other extensions and (for inexplicable
2041reasons) perl itself often is linked against pthreads, so this limitation
2042applies to quite a lot of perls.
1370 2043
1371Before the fork, IO::AIO enters a quiescent state where no requests 2044This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1372can be added in other threads and no results will be processed. After 2045only works in the process that loaded it. Forking is fully supported, but
1373the fork the parent simply leaves the quiescent state and continues 2046using IO::AIO in the child is not.
1374request/result processing, while the child frees the request/result queue
1375(so that the requests started before the fork will only be handled in the
1376parent). Threads will be started on demand until the limit set in the
1377parent process has been reached again.
1378 2047
1379In short: the parent will, after a short pause, continue as if fork had 2048You might get around by not I<using> IO::AIO before (or after)
1380not been called, while the child will act as if IO::AIO has not been used 2049forking. You could also try to call the L<IO::AIO::reinit> function in the
1381yet. 2050child:
2051
2052=over 4
2053
2054=item IO::AIO::reinit
2055
2056Abandons all current requests and I/O threads and simply reinitialises all
2057data structures. This is not an operation supported by any standards, but
2058happens to work on GNU/Linux and some newer BSD systems.
2059
2060The only reasonable use for this function is to call it after forking, if
2061C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
2062the process will result in undefined behaviour. Calling it at any time
2063will also result in any undefined (by POSIX) behaviour.
2064
2065=back
1382 2066
1383=head2 MEMORY USAGE 2067=head2 MEMORY USAGE
1384 2068
1385Per-request usage: 2069Per-request usage:
1386 2070
1403 2087
1404Known bugs will be fixed in the next release. 2088Known bugs will be fixed in the next release.
1405 2089
1406=head1 SEE ALSO 2090=head1 SEE ALSO
1407 2091
1408L<Coro::AIO>. 2092L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
2093more natural syntax.
1409 2094
1410=head1 AUTHOR 2095=head1 AUTHOR
1411 2096
1412 Marc Lehmann <schmorp@schmorp.de> 2097 Marc Lehmann <schmorp@schmorp.de>
1413 http://home.schmorp.de/ 2098 http://home.schmorp.de/

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