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Revision 1.85 by root, Sat Oct 28 01:40:30 2006 UTC vs.
Revision 1.175 by root, Sun Jan 10 20:37:33 2010 UTC

5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
9 aio_open "/etc/passwd", O_RDONLY, 0, sub { 9 aio_open "/etc/passwd", O_RDONLY, 0, sub {
10 my ($fh) = @_; 10 my $fh = shift
11 or die "/etc/passwd: $!";
11 ... 12 ...
12 }; 13 };
13 14
14 aio_unlink "/tmp/file", sub { }; 15 aio_unlink "/tmp/file", sub { };
15 16
25 $req->cancel; # cancel request if still in queue 26 $req->cancel; # cancel request if still in queue
26 27
27 my $grp = aio_group sub { print "all stats done\n" }; 28 my $grp = aio_group sub { print "all stats done\n" };
28 add $grp aio_stat "..." for ...; 29 add $grp aio_stat "..." for ...;
29 30
30 # AnyEvent integration
31 open my $fh, "<&=" . IO::AIO::poll_fileno or die "$!";
32 my $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { IO::AIO::poll_cb });
33
34 # Event integration
35 Event->io (fd => IO::AIO::poll_fileno,
36 poll => 'r',
37 cb => \&IO::AIO::poll_cb);
38
39 # Glib/Gtk2 integration
40 add_watch Glib::IO IO::AIO::poll_fileno,
41 in => sub { IO::AIO::poll_cb; 1 };
42
43 # Tk integration
44 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
45 readable => \&IO::AIO::poll_cb);
46
47 # Danga::Socket integration
48 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
49 \&IO::AIO::poll_cb);
50
51=head1 DESCRIPTION 31=head1 DESCRIPTION
52 32
53This module implements asynchronous I/O using whatever means your 33This module implements asynchronous I/O using whatever means your
54operating system supports. 34operating system supports. It is implemented as an interface to C<libeio>
35(L<http://software.schmorp.de/pkg/libeio.html>).
55 36
56Asynchronous means that operations that can normally block your program 37Asynchronous means that operations that can normally block your program
57(e.g. reading from disk) will be done asynchronously: the operation 38(e.g. reading from disk) will be done asynchronously: the operation
58will 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
59is extremely useful for programs that need to stay interactive even 40is extremely useful for programs that need to stay interactive even
61etc.), but can also be used to easily do operations in parallel that are 42etc.), but can also be used to easily do operations in parallel that are
62normally done sequentially, e.g. stat'ing many files, which is much faster 43normally done sequentially, e.g. stat'ing many files, which is much faster
63on 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
64concurrently. 45concurrently.
65 46
66While this works on all types of file descriptors (for example sockets), 47While most of this works on all types of file descriptors (for
67using these functions on file descriptors that support nonblocking 48example sockets), using these functions on file descriptors that
68operation (again, sockets, pipes etc.) is very inefficient. Use an event 49support nonblocking operation (again, sockets, pipes etc.) is
69loop for that (such as the L<Event|Event> module): IO::AIO will naturally 50very inefficient. Use an event loop for that (such as the L<EV>
70fit into such an event loop itself. 51module): IO::AIO will naturally fit into such an event loop itself.
71 52
72In this version, a number of threads are started that execute your 53In this version, a number of threads are started that execute your
73requests and signal their completion. You don't need thread support 54requests and signal their completion. You don't need thread support
74in 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
75to perl. In the future, this module might make use of the native aio 56to perl. In the future, this module might make use of the native aio
77not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
78files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
79aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
80using threads anyway. 61using threads anyway.
81 62
82Although the module will work with in the presence of other (Perl-) 63Although the module will work in the presence of other (Perl-) threads,
83threads, it is currently not reentrant in any way, so use appropriate 64it is currently not reentrant in any way, so use appropriate locking
84locking yourself, always call C<poll_cb> from within the same thread, or 65yourself, always call C<poll_cb> from within the same thread, or never
85never call C<poll_cb> (or other C<aio_> functions) recursively. 66call C<poll_cb> (or other C<aio_> functions) recursively.
67
68=head2 EXAMPLE
69
70This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously:
72
73 use Fcntl;
74 use EV;
75 use IO::AIO;
76
77 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
79
80 # queue the request to open /etc/passwd
81 aio_open "/etc/passwd", O_RDONLY, 0, sub {
82 my $fh = shift
83 or die "error while opening: $!";
84
85 # stat'ing filehandles is generally non-blocking
86 my $size = -s $fh;
87
88 # queue a request to read the file
89 my $contents;
90 aio_read $fh, 0, $size, $contents, 0, sub {
91 $_[0] == $size
92 or die "short read: $!";
93
94 close $fh;
95
96 # file contents now in $contents
97 print $contents;
98
99 # exit event loop and program
100 EV::unloop;
101 };
102 };
103
104 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc.
106
107 # process events as long as there are some:
108 EV::loop;
86 109
87=head1 REQUEST ANATOMY AND LIFETIME 110=head1 REQUEST ANATOMY AND LIFETIME
88 111
89Every 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
90directly visible to Perl. 113directly visible to Perl.
132Request has reached the end of its lifetime and holds no resources anymore 155Request has reached the end of its lifetime and holds no resources anymore
133(except possibly for the Perl object, but its connection to the actual 156(except possibly for the Perl object, but its connection to the actual
134aio request is severed and calling its methods will either do nothing or 157aio request is severed and calling its methods will either do nothing or
135result in a runtime error). 158result in a runtime error).
136 159
160=back
161
137=cut 162=cut
138 163
139package IO::AIO; 164package IO::AIO;
140 165
141no warnings; 166use Carp ();
142use strict 'vars'; 167
168use common::sense;
143 169
144use base 'Exporter'; 170use base 'Exporter';
145 171
146BEGIN { 172BEGIN {
147 our $VERSION = '2.0'; 173 our $VERSION = '3.5';
148 174
149 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat 175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close
150 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
151 aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move 177 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync
152 aio_copy aio_group aio_nop aio_mknod); 178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead
179 aio_rename aio_link aio_move aio_copy aio_group
180 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181 aio_chmod aio_utime aio_truncate
182 aio_msync aio_mtouch aio_statvfs);
183
153 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 184 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
154 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 185 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
155 min_parallel max_parallel nreqs nready npending); 186 min_parallel max_parallel max_idle
187 nreqs nready npending nthreads
188 max_poll_time max_poll_reqs
189 sendfile fadvise);
190
191 push @AIO_REQ, qw(aio_busy); # not exported
156 192
157 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 193 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
158 194
159 require XSLoader; 195 require XSLoader;
160 XSLoader::load ("IO::AIO", $VERSION); 196 XSLoader::load ("IO::AIO", $VERSION);
161} 197}
162 198
163=head1 FUNCTIONS 199=head1 FUNCTIONS
164 200
201=head2 QUICK OVERVIEW
202
203This section simply lists the prototypes of the most important functions
204for quick reference. See the following sections for function-by-function
205documentation.
206
207 aio_open $pathname, $flags, $mode, $callback->($fh)
208 aio_close $fh, $callback->($status)
209 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
210 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
211 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
212 aio_readahead $fh,$offset,$length, $callback->($retval)
213 aio_stat $fh_or_path, $callback->($status)
214 aio_lstat $fh, $callback->($status)
215 aio_statvfs $fh_or_path, $callback->($statvfs)
216 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
217 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
218 aio_truncate $fh_or_path, $offset, $callback->($status)
219 aio_chmod $fh_or_path, $mode, $callback->($status)
220 aio_unlink $pathname, $callback->($status)
221 aio_mknod $path, $mode, $dev, $callback->($status)
222 aio_link $srcpath, $dstpath, $callback->($status)
223 aio_symlink $srcpath, $dstpath, $callback->($status)
224 aio_readlink $path, $callback->($link)
225 aio_rename $srcpath, $dstpath, $callback->($status)
226 aio_mkdir $pathname, $mode, $callback->($status)
227 aio_rmdir $pathname, $callback->($status)
228 aio_readdir $pathname, $callback->($entries)
229 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
230 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
231 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
232 aio_load $path, $data, $callback->($status)
233 aio_copy $srcpath, $dstpath, $callback->($status)
234 aio_move $srcpath, $dstpath, $callback->($status)
235 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
236 aio_rmtree $path, $callback->($status)
237 aio_sync $callback->($status)
238 aio_fsync $fh, $callback->($status)
239 aio_fdatasync $fh, $callback->($status)
240 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
241 aio_pathsync $path, $callback->($status)
242 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
243 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
244 aio_group $callback->(...)
245 aio_nop $callback->()
246
247 $prev_pri = aioreq_pri [$pri]
248 aioreq_nice $pri_adjust
249
250 IO::AIO::poll_wait
251 IO::AIO::poll_cb
252 IO::AIO::poll
253 IO::AIO::flush
254 IO::AIO::max_poll_reqs $nreqs
255 IO::AIO::max_poll_time $seconds
256 IO::AIO::min_parallel $nthreads
257 IO::AIO::max_parallel $nthreads
258 IO::AIO::max_idle $nthreads
259 IO::AIO::max_outstanding $maxreqs
260 IO::AIO::nreqs
261 IO::AIO::nready
262 IO::AIO::npending
263
264 IO::AIO::sendfile $ofh, $ifh, $offset, $count
265 IO::AIO::fadvise $fh, $offset, $len, $advice
266 IO::AIO::mlockall $flags
267 IO::AIO::munlockall
268
165=head2 AIO FUNCTIONS 269=head2 AIO REQUEST FUNCTIONS
166 270
167All the C<aio_*> calls are more or less thin wrappers around the syscall 271All the C<aio_*> calls are more or less thin wrappers around the syscall
168with the same name (sans C<aio_>). The arguments are similar or identical, 272with the same name (sans C<aio_>). The arguments are similar or identical,
169and they all accept an additional (and optional) C<$callback> argument 273and they all accept an additional (and optional) C<$callback> argument
170which must be a code reference. This code reference will get called with 274which must be a code reference. This code reference will get called with
171the syscall return code (e.g. most syscalls return C<-1> on error, unlike 275the syscall return code (e.g. most syscalls return C<-1> on error, unlike
172perl, which usually delivers "false") as it's sole argument when the given 276perl, which usually delivers "false") as its sole argument after the given
173syscall has been executed asynchronously. 277syscall has been executed asynchronously.
174 278
175All functions expecting a filehandle keep a copy of the filehandle 279All functions expecting a filehandle keep a copy of the filehandle
176internally until the request has finished. 280internally until the request has finished.
177 281
178All requests return objects of type L<IO::AIO::REQ> that allow further 282All functions return request objects of type L<IO::AIO::REQ> that allow
179manipulation of those requests while they are in-flight. 283further manipulation of those requests while they are in-flight.
180 284
181The pathnames you pass to these routines I<must> be absolute and 285The pathnames you pass to these routines I<must> be absolute and
182encoded in byte form. The reason for the former is that at the time the 286encoded as octets. The reason for the former is that at the time the
183request is being executed, the current working directory could have 287request is being executed, the current working directory could have
184changed. Alternatively, you can make sure that you never change the 288changed. Alternatively, you can make sure that you never change the
185current working directory. 289current working directory anywhere in the program and then use relative
290paths.
186 291
187To encode pathnames to byte form, either make sure you either: a) 292To encode pathnames as octets, either make sure you either: a) always pass
188always pass in filenames you got from outside (command line, readdir 293in filenames you got from outside (command line, readdir etc.) without
189etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode 294tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
190your pathnames to the locale (or other) encoding in effect in the user 295your pathnames to the locale (or other) encoding in effect in the user
191environment, d) use Glib::filename_from_unicode on unicode filenames or e) 296environment, d) use Glib::filename_from_unicode on unicode filenames or e)
192use something else. 297use something else to ensure your scalar has the correct contents.
298
299This works, btw. independent of the internal UTF-8 bit, which IO::AIO
300handles correctly whether it is set or not.
193 301
194=over 4 302=over 4
195 303
196=item $prev_pri = aioreq_pri [$pri] 304=item $prev_pri = aioreq_pri [$pri]
197 305
217 aio_read $_[0], ..., sub { 325 aio_read $_[0], ..., sub {
218 ... 326 ...
219 }; 327 };
220 }; 328 };
221 329
330
222=item aioreq_nice $pri_adjust 331=item aioreq_nice $pri_adjust
223 332
224Similar to C<aioreq_pri>, but subtracts the given value from the current 333Similar to C<aioreq_pri>, but subtracts the given value from the current
225priority, so effects are cumulative. 334priority, so the effect is cumulative.
335
226 336
227=item aio_open $pathname, $flags, $mode, $callback->($fh) 337=item aio_open $pathname, $flags, $mode, $callback->($fh)
228 338
229Asynchronously open or create a file and call the callback with a newly 339Asynchronously open or create a file and call the callback with a newly
230created filehandle for the file. 340created filehandle for the file.
236list. They are the same as used by C<sysopen>. 346list. They are the same as used by C<sysopen>.
237 347
238Likewise, C<$mode> specifies the mode of the newly created file, if it 348Likewise, C<$mode> specifies the mode of the newly created file, if it
239didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>, 349didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
240except that it is mandatory (i.e. use C<0> if you don't create new files, 350except that it is mandatory (i.e. use C<0> if you don't create new files,
241and C<0666> or C<0777> if you do). 351and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
352by the umask in effect then the request is being executed, so better never
353change the umask.
242 354
243Example: 355Example:
244 356
245 aio_open "/etc/passwd", O_RDONLY, 0, sub { 357 aio_open "/etc/passwd", O_RDONLY, 0, sub {
246 if ($_[0]) { 358 if ($_[0]) {
249 } else { 361 } else {
250 die "open failed: $!\n"; 362 die "open failed: $!\n";
251 } 363 }
252 }; 364 };
253 365
366
254=item aio_close $fh, $callback->($status) 367=item aio_close $fh, $callback->($status)
255 368
256Asynchronously close a file and call the callback with the result 369Asynchronously close a file and call the callback with the result
257code. I<WARNING:> although accepted, you should not pass in a perl 370code.
258filehandle here, as perl will likely close the file descriptor another
259time when the filehandle is destroyed. Normally, you can safely call perls
260C<close> or just let filehandles go out of scope.
261 371
262This is supposed to be a bug in the API, so that might change. It's 372Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
263therefore best to avoid this function. 373closing the file descriptor associated with the filehandle itself.
374
375Therefore, C<aio_close> will not close the filehandle - instead it will
376use dup2 to overwrite the file descriptor with the write-end of a pipe
377(the pipe fd will be created on demand and will be cached).
378
379Or in other words: the file descriptor will be closed, but it will not be
380free for reuse until the perl filehandle is closed.
381
382=cut
264 383
265=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 384=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
266 385
267=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 386=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
268 387
269Reads or writes C<length> bytes from the specified C<fh> and C<offset> 388Reads or writes C<$length> bytes from or to the specified C<$fh> and
270into the scalar given by C<data> and offset C<dataoffset> and calls the 389C<$offset> into the scalar given by C<$data> and offset C<$dataoffset>
271callback without the actual number of bytes read (or -1 on error, just 390and calls the callback without the actual number of bytes read (or -1 on
272like the syscall). 391error, just like the syscall).
392
393C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
394offset plus the actual number of bytes read.
395
396If C<$offset> is undefined, then the current file descriptor offset will
397be used (and updated), otherwise the file descriptor offset will not be
398changed by these calls.
399
400If C<$length> is undefined in C<aio_write>, use the remaining length of
401C<$data>.
402
403If C<$dataoffset> is less than zero, it will be counted from the end of
404C<$data>.
273 405
274The C<$data> scalar I<MUST NOT> be modified in any way while the request 406The C<$data> scalar I<MUST NOT> be modified in any way while the request
275is outstanding. Modifying it can result in segfaults or WW3 (if the 407is outstanding. Modifying it can result in segfaults or World War III (if
276necessary/optional hardware is installed). 408the necessary/optional hardware is installed).
277 409
278Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at 410Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
279offset C<0> within the scalar: 411offset C<0> within the scalar:
280 412
281 aio_read $fh, 7, 15, $buffer, 0, sub { 413 aio_read $fh, 7, 15, $buffer, 0, sub {
282 $_[0] > 0 or die "read error: $!"; 414 $_[0] > 0 or die "read error: $!";
283 print "read $_[0] bytes: <$buffer>\n"; 415 print "read $_[0] bytes: <$buffer>\n";
284 }; 416 };
417
285 418
286=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 419=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
287 420
288Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 421Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
289reading at byte offset C<$in_offset>, and starts writing at the current 422reading at byte offset C<$in_offset>, and starts writing at the current
293 426
294This call tries to make use of a native C<sendfile> syscall to provide 427This call tries to make use of a native C<sendfile> syscall to provide
295zero-copy operation. For this to work, C<$out_fh> should refer to a 428zero-copy operation. For this to work, C<$out_fh> should refer to a
296socket, and C<$in_fh> should refer to mmap'able file. 429socket, and C<$in_fh> should refer to mmap'able file.
297 430
298If the native sendfile call fails or is not implemented, it will be 431If a native sendfile cannot be found or it fails with C<ENOSYS>,
432C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,
299emulated, so you can call C<aio_sendfile> on any type of filehandle 433it will be emulated, so you can call C<aio_sendfile> on any type of
300regardless of the limitations of the operating system. 434filehandle regardless of the limitations of the operating system.
301 435
302Please note, however, that C<aio_sendfile> can read more bytes from 436Please note, however, that C<aio_sendfile> can read more bytes from
303C<$in_fh> than are written, and there is no way to find out how many 437C<$in_fh> than are written, and there is no way to find out how many
304bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 438bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
305provides the number of bytes written to C<$out_fh>. Only if the result 439provides the number of bytes written to C<$out_fh>. Only if the result
306value equals C<$length> one can assume that C<$length> bytes have been 440value equals C<$length> one can assume that C<$length> bytes have been
307read. 441read.
442
308 443
309=item aio_readahead $fh,$offset,$length, $callback->($retval) 444=item aio_readahead $fh,$offset,$length, $callback->($retval)
310 445
311C<aio_readahead> populates the page cache with data from a file so that 446C<aio_readahead> populates the page cache with data from a file so that
312subsequent reads from that file will not block on disk I/O. The C<$offset> 447subsequent reads from that file will not block on disk I/O. The C<$offset>
318file. The current file offset of the file is left unchanged. 453file. The current file offset of the file is left unchanged.
319 454
320If that syscall doesn't exist (likely if your OS isn't Linux) it will be 455If that syscall doesn't exist (likely if your OS isn't Linux) it will be
321emulated by simply reading the data, which would have a similar effect. 456emulated by simply reading the data, which would have a similar effect.
322 457
458
323=item aio_stat $fh_or_path, $callback->($status) 459=item aio_stat $fh_or_path, $callback->($status)
324 460
325=item aio_lstat $fh, $callback->($status) 461=item aio_lstat $fh, $callback->($status)
326 462
327Works like perl's C<stat> or C<lstat> in void context. The callback will 463Works like perl's C<stat> or C<lstat> in void context. The callback will
340 aio_stat "/etc/passwd", sub { 476 aio_stat "/etc/passwd", sub {
341 $_[0] and die "stat failed: $!"; 477 $_[0] and die "stat failed: $!";
342 print "size is ", -s _, "\n"; 478 print "size is ", -s _, "\n";
343 }; 479 };
344 480
481
482=item aio_statvfs $fh_or_path, $callback->($statvfs)
483
484Works like the POSIX C<statvfs> or C<fstatvfs> syscalls, depending on
485whether a file handle or path was passed.
486
487On success, the callback is passed a hash reference with the following
488members: C<bsize>, C<frsize>, C<blocks>, C<bfree>, C<bavail>, C<files>,
489C<ffree>, C<favail>, C<fsid>, C<flag> and C<namemax>. On failure, C<undef>
490is passed.
491
492The following POSIX IO::AIO::ST_* constants are defined: C<ST_RDONLY> and
493C<ST_NOSUID>.
494
495The following non-POSIX IO::AIO::ST_* flag masks are defined to
496their correct value when available, or to C<0> on systems that do
497not support them: C<ST_NODEV>, C<ST_NOEXEC>, C<ST_SYNCHRONOUS>,
498C<ST_MANDLOCK>, C<ST_WRITE>, C<ST_APPEND>, C<ST_IMMUTABLE>, C<ST_NOATIME>,
499C<ST_NODIRATIME> and C<ST_RELATIME>.
500
501Example: stat C</wd> and dump out the data if successful.
502
503 aio_statvfs "/wd", sub {
504 my $f = $_[0]
505 or die "statvfs: $!";
506
507 use Data::Dumper;
508 say Dumper $f;
509 };
510
511 # result:
512 {
513 bsize => 1024,
514 bfree => 4333064312,
515 blocks => 10253828096,
516 files => 2050765568,
517 flag => 4096,
518 favail => 2042092649,
519 bavail => 4333064312,
520 ffree => 2042092649,
521 namemax => 255,
522 frsize => 1024,
523 fsid => 1810
524 }
525
526
527=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
528
529Works like perl's C<utime> function (including the special case of $atime
530and $mtime being undef). Fractional times are supported if the underlying
531syscalls support them.
532
533When called with a pathname, uses utimes(2) if available, otherwise
534utime(2). If called on a file descriptor, uses futimes(2) if available,
535otherwise returns ENOSYS, so this is not portable.
536
537Examples:
538
539 # set atime and mtime to current time (basically touch(1)):
540 aio_utime "path", undef, undef;
541 # set atime to current time and mtime to beginning of the epoch:
542 aio_utime "path", time, undef; # undef==0
543
544
545=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
546
547Works like perl's C<chown> function, except that C<undef> for either $uid
548or $gid is being interpreted as "do not change" (but -1 can also be used).
549
550Examples:
551
552 # same as "chown root path" in the shell:
553 aio_chown "path", 0, -1;
554 # same as above:
555 aio_chown "path", 0, undef;
556
557
558=item aio_truncate $fh_or_path, $offset, $callback->($status)
559
560Works like truncate(2) or ftruncate(2).
561
562
563=item aio_chmod $fh_or_path, $mode, $callback->($status)
564
565Works like perl's C<chmod> function.
566
567
345=item aio_unlink $pathname, $callback->($status) 568=item aio_unlink $pathname, $callback->($status)
346 569
347Asynchronously unlink (delete) a file and call the callback with the 570Asynchronously unlink (delete) a file and call the callback with the
348result code. 571result code.
349 572
573
350=item aio_mknod $path, $mode, $dev, $callback->($status) 574=item aio_mknod $path, $mode, $dev, $callback->($status)
351 575
576[EXPERIMENTAL]
577
352Asynchronously create a device node (or fifo). See mknod(2). 578Asynchronously create a device node (or fifo). See mknod(2).
353 579
354The only portable (POSIX) way of calling this function is: 580The only (POSIX-) portable way of calling this function is:
355 581
356 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 582 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ...
583
357 584
358=item aio_link $srcpath, $dstpath, $callback->($status) 585=item aio_link $srcpath, $dstpath, $callback->($status)
359 586
360Asynchronously create a new link to the existing object at C<$srcpath> at 587Asynchronously create a new link to the existing object at C<$srcpath> at
361the path C<$dstpath> and call the callback with the result code. 588the path C<$dstpath> and call the callback with the result code.
362 589
590
363=item aio_symlink $srcpath, $dstpath, $callback->($status) 591=item aio_symlink $srcpath, $dstpath, $callback->($status)
364 592
365Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 593Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
366the path C<$dstpath> and call the callback with the result code. 594the path C<$dstpath> and call the callback with the result code.
367 595
596
597=item aio_readlink $path, $callback->($link)
598
599Asynchronously read the symlink specified by C<$path> and pass it to
600the callback. If an error occurs, nothing or undef gets passed to the
601callback.
602
603
368=item aio_rename $srcpath, $dstpath, $callback->($status) 604=item aio_rename $srcpath, $dstpath, $callback->($status)
369 605
370Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 606Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
371rename(2) and call the callback with the result code. 607rename(2) and call the callback with the result code.
372 608
609
610=item aio_mkdir $pathname, $mode, $callback->($status)
611
612Asynchronously mkdir (create) a directory and call the callback with
613the result code. C<$mode> will be modified by the umask at the time the
614request is executed, so do not change your umask.
615
616
373=item aio_rmdir $pathname, $callback->($status) 617=item aio_rmdir $pathname, $callback->($status)
374 618
375Asynchronously rmdir (delete) a directory and call the callback with the 619Asynchronously rmdir (delete) a directory and call the callback with the
376result code. 620result code.
621
377 622
378=item aio_readdir $pathname, $callback->($entries) 623=item aio_readdir $pathname, $callback->($entries)
379 624
380Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 625Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
381directory (i.e. opendir + readdir + closedir). The entries will not be 626directory (i.e. opendir + readdir + closedir). The entries will not be
382sorted, and will B<NOT> include the C<.> and C<..> entries. 627sorted, and will B<NOT> include the C<.> and C<..> entries.
383 628
384The callback a single argument which is either C<undef> or an array-ref 629The callback is passed a single argument which is either C<undef> or an
385with the filenames. 630array-ref with the filenames.
631
632
633=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
634
635Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune
636behaviour and output format. In case of an error, C<$entries> will be
637C<undef>.
638
639The flags are a combination of the following constants, ORed together (the
640flags will also be passed to the callback, possibly modified):
641
642=over 4
643
644=item IO::AIO::READDIR_DENTS
645
646When this flag is off, then the callback gets an arrayref with of names
647only (as with C<aio_readdir>), otherwise it gets an arrayref with
648C<[$name, $type, $inode]> arrayrefs, each describing a single directory
649entry in more detail.
650
651C<$name> is the name of the entry.
652
653C<$type> is one of the C<IO::AIO::DT_xxx> constants:
654
655C<IO::AIO::DT_UNKNOWN>, C<IO::AIO::DT_FIFO>, C<IO::AIO::DT_CHR>, C<IO::AIO::DT_DIR>,
656C<IO::AIO::DT_BLK>, C<IO::AIO::DT_REG>, C<IO::AIO::DT_LNK>, C<IO::AIO::DT_SOCK>,
657C<IO::AIO::DT_WHT>.
658
659C<IO::AIO::DT_UNKNOWN> means just that: readdir does not know. If you need to
660know, you have to run stat yourself. Also, for speed reasons, the C<$type>
661scalars are read-only: you can not modify them.
662
663C<$inode> is the inode number (which might not be exact on systems with 64
664bit inode numbers and 32 bit perls). This field has unspecified content on
665systems that do not deliver the inode information.
666
667=item IO::AIO::READDIR_DIRS_FIRST
668
669When this flag is set, then the names will be returned in an order where
670likely directories come first. This is useful when you need to quickly
671find directories, or you want to find all directories while avoiding to
672stat() each entry.
673
674If the system returns type information in readdir, then this is used
675to find directories directly. Otherwise, likely directories are files
676beginning with ".", or otherwise files with no dots, of which files with
677short names are tried first.
678
679=item IO::AIO::READDIR_STAT_ORDER
680
681When this flag is set, then the names will be returned in an order
682suitable for stat()'ing each one. That is, when you plan to stat()
683all files in the given directory, then the returned order will likely
684be fastest.
685
686If both this flag and C<IO::AIO::READDIR_DIRS_FIRST> are specified, then
687the likely dirs come first, resulting in a less optimal stat order.
688
689=item IO::AIO::READDIR_FOUND_UNKNOWN
690
691This flag should not be set when calling C<aio_readdirx>. Instead, it
692is being set by C<aio_readdirx>, when any of the C<$type>'s found were
693C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all
694C<$type>'s are known, which can be used to speed up some algorithms.
695
696=back
697
698
699=item aio_load $path, $data, $callback->($status)
700
701This is a composite request that tries to fully load the given file into
702memory. Status is the same as with aio_read.
703
704=cut
705
706sub aio_load($$;$) {
707 my ($path, undef, $cb) = @_;
708 my $data = \$_[1];
709
710 my $pri = aioreq_pri;
711 my $grp = aio_group $cb;
712
713 aioreq_pri $pri;
714 add $grp aio_open $path, O_RDONLY, 0, sub {
715 my $fh = shift
716 or return $grp->result (-1);
717
718 aioreq_pri $pri;
719 add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
720 $grp->result ($_[0]);
721 };
722 };
723
724 $grp
725}
386 726
387=item aio_copy $srcpath, $dstpath, $callback->($status) 727=item aio_copy $srcpath, $dstpath, $callback->($status)
388 728
389Try to copy the I<file> (directories not supported as either source or 729Try to copy the I<file> (directories not supported as either source or
390destination) from C<$srcpath> to C<$dstpath> and call the callback with 730destination) from C<$srcpath> to C<$dstpath> and call the callback with
391the C<0> (error) or C<-1> ok. 731a status of C<0> (ok) or C<-1> (error, see C<$!>).
392 732
393This is a composite request that it creates the destination file with 733This is a composite request that creates the destination file with
394mode 0200 and copies the contents of the source file into it using 734mode 0200 and copies the contents of the source file into it using
395C<aio_sendfile>, followed by restoring atime, mtime, access mode and 735C<aio_sendfile>, followed by restoring atime, mtime, access mode and
396uid/gid, in that order. 736uid/gid, in that order.
397 737
398If an error occurs, the partial destination file will be unlinked, if 738If an error occurs, the partial destination file will be unlinked, if
408 my $grp = aio_group $cb; 748 my $grp = aio_group $cb;
409 749
410 aioreq_pri $pri; 750 aioreq_pri $pri;
411 add $grp aio_open $src, O_RDONLY, 0, sub { 751 add $grp aio_open $src, O_RDONLY, 0, sub {
412 if (my $src_fh = $_[0]) { 752 if (my $src_fh = $_[0]) {
413 my @stat = stat $src_fh; 753 my @stat = stat $src_fh; # hmm, might block over nfs?
414 754
415 aioreq_pri $pri; 755 aioreq_pri $pri;
416 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub { 756 add $grp aio_open $dst, O_CREAT | O_WRONLY | O_TRUNC, 0200, sub {
417 if (my $dst_fh = $_[0]) { 757 if (my $dst_fh = $_[0]) {
418 aioreq_pri $pri; 758 aioreq_pri $pri;
419 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub { 759 add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
420 if ($_[0] == $stat[7]) { 760 if ($_[0] == $stat[7]) {
421 $grp->result (0); 761 $grp->result (0);
422 close $src_fh; 762 close $src_fh;
423 763
424 # those should not normally block. should. should. 764 my $ch = sub {
765 aioreq_pri $pri;
766 add $grp aio_chmod $dst_fh, $stat[2] & 07777, sub {
767 aioreq_pri $pri;
768 add $grp aio_chown $dst_fh, $stat[4], $stat[5], sub {
769 aioreq_pri $pri;
770 add $grp aio_close $dst_fh;
771 }
772 };
773 };
774
775 aioreq_pri $pri;
776 add $grp aio_utime $dst_fh, $stat[8], $stat[9], sub {
777 if ($_[0] < 0 && $! == ENOSYS) {
778 aioreq_pri $pri;
425 utime $stat[8], $stat[9], $dst; 779 add $grp aio_utime $dst, $stat[8], $stat[9], $ch;
426 chmod $stat[2] & 07777, $dst_fh; 780 } else {
427 chown $stat[4], $stat[5], $dst_fh; 781 $ch->();
782 }
428 close $dst_fh; 783 };
429 } else { 784 } else {
430 $grp->result (-1); 785 $grp->result (-1);
431 close $src_fh; 786 close $src_fh;
432 close $dst_fh; 787 close $dst_fh;
433 788
450 805
451=item aio_move $srcpath, $dstpath, $callback->($status) 806=item aio_move $srcpath, $dstpath, $callback->($status)
452 807
453Try to move the I<file> (directories not supported as either source or 808Try to move the I<file> (directories not supported as either source or
454destination) from C<$srcpath> to C<$dstpath> and call the callback with 809destination) from C<$srcpath> to C<$dstpath> and call the callback with
455the C<0> (error) or C<-1> ok. 810a status of C<0> (ok) or C<-1> (error, see C<$!>).
456 811
457This is a composite request that tries to rename(2) the file first. If 812This is a composite request that tries to rename(2) the file first; if
458rename files with C<EXDEV>, it copies the file with C<aio_copy> and, if 813rename fails with C<EXDEV>, it copies the file with C<aio_copy> and, if
459that is successful, unlinking the C<$srcpath>. 814that is successful, unlinks the C<$srcpath>.
460 815
461=cut 816=cut
462 817
463sub aio_move($$;$) { 818sub aio_move($$;$) {
464 my ($src, $dst, $cb) = @_; 819 my ($src, $dst, $cb) = @_;
511 866
512Implementation notes. 867Implementation notes.
513 868
514The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can. 869The C<aio_readdir> cannot be avoided, but C<stat()>'ing every entry can.
515 870
871If readdir returns file type information, then this is used directly to
872find directories.
873
516After reading the directory, the modification time, size etc. of the 874Otherwise, after reading the directory, the modification time, size etc.
517directory before and after the readdir is checked, and if they match (and 875of the directory before and after the readdir is checked, and if they
518isn't the current time), the link count will be used to decide how many 876match (and isn't the current time), the link count will be used to decide
519entries are directories (if >= 2). Otherwise, no knowledge of the number 877how many entries are directories (if >= 2). Otherwise, no knowledge of the
520of subdirectories will be assumed. 878number of subdirectories will be assumed.
521 879
522Then entries will be sorted into likely directories (everything without 880Then entries will be sorted into likely directories a non-initial dot
523a non-initial dot currently) and likely non-directories (everything 881currently) and likely non-directories (see C<aio_readdirx>). Then every
524else). Then every entry plus an appended C</.> will be C<stat>'ed, 882entry plus an appended C</.> will be C<stat>'ed, likely directories first,
525likely directories first. If that succeeds, it assumes that the entry 883in order of their inode numbers. If that succeeds, it assumes that the
526is a directory or a symlink to directory (which will be checked 884entry is a directory or a symlink to directory (which will be checked
527seperately). This is often faster than stat'ing the entry itself because 885seperately). This is often faster than stat'ing the entry itself because
528filesystems might detect the type of the entry without reading the inode 886filesystems might detect the type of the entry without reading the inode
529data (e.g. ext2fs filetype feature). 887data (e.g. ext2fs filetype feature), even on systems that cannot return
888the filetype information on readdir.
530 889
531If the known number of directories (link count - 2) has been reached, the 890If the known number of directories (link count - 2) has been reached, the
532rest of the entries is assumed to be non-directories. 891rest of the entries is assumed to be non-directories.
533 892
534This only works with certainty on POSIX (= UNIX) filesystems, which 893This only works with certainty on POSIX (= UNIX) filesystems, which
538as those tend to return 0 or 1 as link counts, which disables the 897as those tend to return 0 or 1 as link counts, which disables the
539directory counting heuristic. 898directory counting heuristic.
540 899
541=cut 900=cut
542 901
543sub aio_scandir($$$) { 902sub aio_scandir($$;$) {
544 my ($path, $maxreq, $cb) = @_; 903 my ($path, $maxreq, $cb) = @_;
545 904
546 my $pri = aioreq_pri; 905 my $pri = aioreq_pri;
547 906
548 my $grp = aio_group $cb; 907 my $grp = aio_group $cb;
556 my $now = time; 915 my $now = time;
557 my $hash1 = join ":", (stat _)[0,1,3,7,9]; 916 my $hash1 = join ":", (stat _)[0,1,3,7,9];
558 917
559 # read the directory entries 918 # read the directory entries
560 aioreq_pri $pri; 919 aioreq_pri $pri;
561 add $grp aio_readdir $path, sub { 920 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {
562 my $entries = shift 921 my $entries = shift
563 or return $grp->result (); 922 or return $grp->result ();
564 923
565 # stat the dir another time 924 # stat the dir another time
566 aioreq_pri $pri; 925 aioreq_pri $pri;
572 # take the slow route if anything looks fishy 931 # take the slow route if anything looks fishy
573 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 932 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
574 $ndirs = -1; 933 $ndirs = -1;
575 } else { 934 } else {
576 # if nlink == 2, we are finished 935 # if nlink == 2, we are finished
577 # on non-posix-fs's, we rely on nlink < 2 936 # for non-posix-fs's, we rely on nlink < 2
578 $ndirs = (stat _)[3] - 2 937 $ndirs = (stat _)[3] - 2
579 or return $grp->result ([], $entries); 938 or return $grp->result ([], $entries);
580 } 939 }
581 940
582 # sort into likely dirs and likely nondirs
583 # dirs == files without ".", short entries first
584 $entries = [map $_->[0],
585 sort { $b->[1] cmp $a->[1] }
586 map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
587 @$entries];
588
589 my (@dirs, @nondirs); 941 my (@dirs, @nondirs);
590 942
591 my $statgrp = add $grp aio_group sub { 943 my $statgrp = add $grp aio_group sub {
592 $grp->result (\@dirs, \@nondirs); 944 $grp->result (\@dirs, \@nondirs);
593 }; 945 };
594 946
595 limit $statgrp $maxreq; 947 limit $statgrp $maxreq;
596 feed $statgrp sub { 948 feed $statgrp sub {
597 return unless @$entries; 949 return unless @$entries;
598 my $entry = pop @$entries; 950 my $entry = shift @$entries;
599 951
600 aioreq_pri $pri; 952 aioreq_pri $pri;
601 add $statgrp aio_stat "$path/$entry/.", sub { 953 add $statgrp aio_stat "$path/$entry/.", sub {
602 if ($_[0] < 0) { 954 if ($_[0] < 0) {
603 push @nondirs, $entry; 955 push @nondirs, $entry;
624 }; 976 };
625 977
626 $grp 978 $grp
627} 979}
628 980
981=item aio_rmtree $path, $callback->($status)
982
983Delete a directory tree starting (and including) C<$path>, return the
984status of the final C<rmdir> only. This is a composite request that
985uses C<aio_scandir> to recurse into and rmdir directories, and unlink
986everything else.
987
988=cut
989
990sub aio_rmtree;
991sub aio_rmtree($;$) {
992 my ($path, $cb) = @_;
993
994 my $pri = aioreq_pri;
995 my $grp = aio_group $cb;
996
997 aioreq_pri $pri;
998 add $grp aio_scandir $path, 0, sub {
999 my ($dirs, $nondirs) = @_;
1000
1001 my $dirgrp = aio_group sub {
1002 add $grp aio_rmdir $path, sub {
1003 $grp->result ($_[0]);
1004 };
1005 };
1006
1007 (aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
1008 (aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
1009
1010 add $grp $dirgrp;
1011 };
1012
1013 $grp
1014}
1015
1016=item aio_sync $callback->($status)
1017
1018Asynchronously call sync and call the callback when finished.
1019
629=item aio_fsync $fh, $callback->($status) 1020=item aio_fsync $fh, $callback->($status)
630 1021
631Asynchronously call fsync on the given filehandle and call the callback 1022Asynchronously call fsync on the given filehandle and call the callback
632with the fsync result code. 1023with the fsync result code.
633 1024
636Asynchronously call fdatasync on the given filehandle and call the 1027Asynchronously call fdatasync on the given filehandle and call the
637callback with the fdatasync result code. 1028callback with the fdatasync result code.
638 1029
639If this call isn't available because your OS lacks it or it couldn't be 1030If this call isn't available because your OS lacks it or it couldn't be
640detected, it will be emulated by calling C<fsync> instead. 1031detected, it will be emulated by calling C<fsync> instead.
1032
1033=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1034
1035Sync the data portion of the file specified by C<$offset> and C<$length>
1036to disk (but NOT the metadata), by calling the Linux-specific
1037sync_file_range call. If sync_file_range is not available or it returns
1038ENOSYS, then fdatasync or fsync is being substituted.
1039
1040C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1041C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1042C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1043manpage for details.
1044
1045=item aio_pathsync $path, $callback->($status)
1046
1047This request tries to open, fsync and close the given path. This is a
1048composite request intended to sync directories after directory operations
1049(E.g. rename). This might not work on all operating systems or have any
1050specific effect, but usually it makes sure that directory changes get
1051written to disc. It works for anything that can be opened for read-only,
1052not just directories.
1053
1054Future versions of this function might fall back to other methods when
1055C<fsync> on the directory fails (such as calling C<sync>).
1056
1057Passes C<0> when everything went ok, and C<-1> on error.
1058
1059=cut
1060
1061sub aio_pathsync($;$) {
1062 my ($path, $cb) = @_;
1063
1064 my $pri = aioreq_pri;
1065 my $grp = aio_group $cb;
1066
1067 aioreq_pri $pri;
1068 add $grp aio_open $path, O_RDONLY, 0, sub {
1069 my ($fh) = @_;
1070 if ($fh) {
1071 aioreq_pri $pri;
1072 add $grp aio_fsync $fh, sub {
1073 $grp->result ($_[0]);
1074
1075 aioreq_pri $pri;
1076 add $grp aio_close $fh;
1077 };
1078 } else {
1079 $grp->result (-1);
1080 }
1081 };
1082
1083 $grp
1084}
1085
1086=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1087
1088This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1089scalars (see the L<Sys::Mmap> or L<Mmap> modules for details on this, note
1090that the scalar must only be modified in-place while an aio operation is
1091pending on it).
1092
1093It calls the C<msync> function of your OS, if available, with the memory
1094area starting at C<$offset> in the string and ending C<$length> bytes
1095later. If C<$length> is negative, counts from the end, and if C<$length>
1096is C<undef>, then it goes till the end of the string. The flags can be
1097a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and
1098C<IO::AIO::MS_SYNC>.
1099
1100=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1101
1102This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1103scalars.
1104
1105It touches (reads or writes) all memory pages in the specified
1106range inside the scalar. All caveats and parameters are the same
1107as for C<aio_msync>, above, except for flags, which must be either
1108C<0> (which reads all pages and ensures they are instantiated) or
1109C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and
1110writing an octet from it, which dirties the page).
641 1111
642=item aio_group $callback->(...) 1112=item aio_group $callback->(...)
643 1113
644This is a very special aio request: Instead of doing something, it is a 1114This is a very special aio request: Instead of doing something, it is a
645container for other aio requests, which is useful if you want to bundle 1115container for other aio requests, which is useful if you want to bundle
695=item cancel $req 1165=item cancel $req
696 1166
697Cancels the request, if possible. Has the effect of skipping execution 1167Cancels the request, if possible. Has the effect of skipping execution
698when entering the B<execute> state and skipping calling the callback when 1168when entering the B<execute> state and skipping calling the callback when
699entering the the B<result> state, but will leave the request otherwise 1169entering the the B<result> state, but will leave the request otherwise
700untouched. That means that requests that currently execute will not be 1170untouched (with the exception of readdir). That means that requests that
701stopped and resources held by the request will not be freed prematurely. 1171currently execute will not be stopped and resources held by the request
1172will not be freed prematurely.
702 1173
703=item cb $req $callback->(...) 1174=item cb $req $callback->(...)
704 1175
705Replace (or simply set) the callback registered to the request. 1176Replace (or simply set) the callback registered to the request.
706 1177
757Their lifetime, simplified, looks like this: when they are empty, they 1228Their lifetime, simplified, looks like this: when they are empty, they
758will finish very quickly. If they contain only requests that are in the 1229will finish very quickly. If they contain only requests that are in the
759C<done> state, they will also finish. Otherwise they will continue to 1230C<done> state, they will also finish. Otherwise they will continue to
760exist. 1231exist.
761 1232
762That means after creating a group you have some time to add requests. And 1233That means after creating a group you have some time to add requests
763in the callbacks of those requests, you can add further requests to the 1234(precisely before the callback has been invoked, which is only done within
764group. And only when all those requests have finished will the the group 1235the C<poll_cb>). And in the callbacks of those requests, you can add
765itself finish. 1236further requests to the group. And only when all those requests have
1237finished will the the group itself finish.
766 1238
767=over 4 1239=over 4
768 1240
769=item add $grp ... 1241=item add $grp ...
770 1242
779=item $grp->cancel_subs 1251=item $grp->cancel_subs
780 1252
781Cancel all subrequests and clears any feeder, but not the group request 1253Cancel all subrequests and clears any feeder, but not the group request
782itself. Useful when you queued a lot of events but got a result early. 1254itself. Useful when you queued a lot of events but got a result early.
783 1255
1256The group request will finish normally (you cannot add requests to the
1257group).
1258
784=item $grp->result (...) 1259=item $grp->result (...)
785 1260
786Set the result value(s) that will be passed to the group callback when all 1261Set the result value(s) that will be passed to the group callback when all
787subrequests have finished and set thre groups errno to the current value 1262subrequests have finished and set the groups errno to the current value
788of errno (just like calling C<errno> without an error number). By default, 1263of errno (just like calling C<errno> without an error number). By default,
789no argument will be passed and errno is zero. 1264no argument will be passed and errno is zero.
790 1265
791=item $grp->errno ([$errno]) 1266=item $grp->errno ([$errno])
792 1267
803=item feed $grp $callback->($grp) 1278=item feed $grp $callback->($grp)
804 1279
805Sets a feeder/generator on this group: every group can have an attached 1280Sets a feeder/generator on this group: every group can have an attached
806generator that generates requests if idle. The idea behind this is that, 1281generator that generates requests if idle. The idea behind this is that,
807although you could just queue as many requests as you want in a group, 1282although you could just queue as many requests as you want in a group,
808this might starve other requests for a potentially long time. For 1283this might starve other requests for a potentially long time. For example,
809example, C<aio_scandir> might generate hundreds of thousands C<aio_stat> 1284C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,
810requests, delaying any later requests for a long time. 1285delaying any later requests for a long time.
811 1286
812To avoid this, and allow incremental generation of requests, you can 1287To avoid this, and allow incremental generation of requests, you can
813instead a group and set a feeder on it that generates those requests. The 1288instead a group and set a feeder on it that generates those requests. The
814feed callback will be called whenever there are few enough (see C<limit>, 1289feed callback will be called whenever there are few enough (see C<limit>,
815below) requests active in the group itself and is expected to queue more 1290below) requests active in the group itself and is expected to queue more
819not impose any limits). 1294not impose any limits).
820 1295
821If the feed does not queue more requests when called, it will be 1296If the feed does not queue more requests when called, it will be
822automatically removed from the group. 1297automatically removed from the group.
823 1298
824If the feed limit is C<0>, it will be set to C<2> automatically. 1299If the feed limit is C<0> when this method is called, it will be set to
1300C<2> automatically.
825 1301
826Example: 1302Example:
827 1303
828 # stat all files in @files, but only ever use four aio requests concurrently: 1304 # stat all files in @files, but only ever use four aio requests concurrently:
829 1305
841Sets the feeder limit for the group: The feeder will be called whenever 1317Sets the feeder limit for the group: The feeder will be called whenever
842the group contains less than this many requests. 1318the group contains less than this many requests.
843 1319
844Setting the limit to C<0> will pause the feeding process. 1320Setting the limit to C<0> will pause the feeding process.
845 1321
1322The default value for the limit is C<0>, but note that setting a feeder
1323automatically bumps it up to C<2>.
1324
846=back 1325=back
847 1326
848=head2 SUPPORT FUNCTIONS 1327=head2 SUPPORT FUNCTIONS
849 1328
1329=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
1330
850=over 4 1331=over 4
851 1332
852=item $fileno = IO::AIO::poll_fileno 1333=item $fileno = IO::AIO::poll_fileno
853 1334
854Return the I<request result pipe file descriptor>. This filehandle must be 1335Return the I<request result pipe file descriptor>. This filehandle must be
855polled for reading by some mechanism outside this module (e.g. Event or 1336polled for reading by some mechanism outside this module (e.g. EV, Glib,
856select, see below or the SYNOPSIS). If the pipe becomes readable you have 1337select and so on, see below or the SYNOPSIS). If the pipe becomes readable
857to call C<poll_cb> to check the results. 1338you have to call C<poll_cb> to check the results.
858 1339
859See C<poll_cb> for an example. 1340See C<poll_cb> for an example.
860 1341
861=item IO::AIO::poll_cb 1342=item IO::AIO::poll_cb
862 1343
863Process all outstanding events on the result pipe. You have to call this 1344Process some outstanding events on the result pipe. You have to call this
864regularly. Returns the number of events processed. Returns immediately 1345regularly. Returns C<0> if all events could be processed, or C<-1> if it
865when no events are outstanding. 1346returned earlier for whatever reason. Returns immediately when no events
1347are outstanding. The amount of events processed depends on the settings of
1348C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
866 1349
867If not all requests were processed for whatever reason, the filehandle 1350If not all requests were processed for whatever reason, the filehandle
868will still be ready when C<poll_cb> returns. 1351will still be ready when C<poll_cb> returns, so normally you don't have to
1352do anything special to have it called later.
869 1353
870Example: Install an Event watcher that automatically calls 1354Example: Install an Event watcher that automatically calls
871IO::AIO::poll_cb with high priority: 1355IO::AIO::poll_cb with high priority (more examples can be found in the
1356SYNOPSIS section, at the top of this document):
872 1357
873 Event->io (fd => IO::AIO::poll_fileno, 1358 Event->io (fd => IO::AIO::poll_fileno,
874 poll => 'r', async => 1, 1359 poll => 'r', async => 1,
875 cb => \&IO::AIO::poll_cb); 1360 cb => \&IO::AIO::poll_cb);
876 1361
877=item IO::AIO::poll_some $max_requests 1362=item IO::AIO::poll_wait
878 1363
879Similar to C<poll_cb>, but only processes up to C<$max_requests> requests 1364If there are any outstanding requests and none of them in the result
880at a time. 1365phase, wait till the result filehandle becomes ready for reading (simply
1366does a C<select> on the filehandle. This is useful if you want to
1367synchronously wait for some requests to finish).
881 1368
882Useful if you want to ensure some level of interactiveness when perl is 1369See C<nreqs> for an example.
883not fast enough to process all requests in time. 1370
1371=item IO::AIO::poll
1372
1373Waits until some requests have been handled.
1374
1375Returns the number of requests processed, but is otherwise strictly
1376equivalent to:
1377
1378 IO::AIO::poll_wait, IO::AIO::poll_cb
1379
1380=item IO::AIO::flush
1381
1382Wait till all outstanding AIO requests have been handled.
1383
1384Strictly equivalent to:
1385
1386 IO::AIO::poll_wait, IO::AIO::poll_cb
1387 while IO::AIO::nreqs;
1388
1389=item IO::AIO::max_poll_reqs $nreqs
1390
1391=item IO::AIO::max_poll_time $seconds
1392
1393These set the maximum number of requests (default C<0>, meaning infinity)
1394that are being processed by C<IO::AIO::poll_cb> in one call, respectively
1395the maximum amount of time (default C<0>, meaning infinity) spent in
1396C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
1397of time C<poll_cb> is allowed to use).
1398
1399Setting C<max_poll_time> to a non-zero value creates an overhead of one
1400syscall per request processed, which is not normally a problem unless your
1401callbacks are really really fast or your OS is really really slow (I am
1402not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
1403
1404Setting these is useful if you want to ensure some level of
1405interactiveness when perl is not fast enough to process all requests in
1406time.
1407
1408For interactive programs, values such as C<0.01> to C<0.1> should be fine.
884 1409
885Example: Install an Event watcher that automatically calls 1410Example: Install an Event watcher that automatically calls
886IO::AIO::poll_some with low priority, to ensure that other parts of the 1411IO::AIO::poll_cb with low priority, to ensure that other parts of the
887program get the CPU sometimes even under high AIO load. 1412program get the CPU sometimes even under high AIO load.
888 1413
1414 # try not to spend much more than 0.1s in poll_cb
1415 IO::AIO::max_poll_time 0.1;
1416
1417 # use a low priority so other tasks have priority
889 Event->io (fd => IO::AIO::poll_fileno, 1418 Event->io (fd => IO::AIO::poll_fileno,
890 poll => 'r', nice => 1, 1419 poll => 'r', nice => 1,
891 cb => sub { IO::AIO::poll_some 256 }); 1420 cb => &IO::AIO::poll_cb);
892 1421
893=item IO::AIO::poll_wait 1422=back
894 1423
895Wait till the result filehandle becomes ready for reading (simply does a 1424=head3 CONTROLLING THE NUMBER OF THREADS
896C<select> on the filehandle. This is useful if you want to synchronously wait
897for some requests to finish).
898 1425
899See C<nreqs> for an example. 1426=over
900
901=item IO::AIO::nreqs
902
903Returns the number of requests currently in the ready, execute or pending
904states (i.e. for which their callback has not been invoked yet).
905
906Example: wait till there are no outstanding requests anymore:
907
908 IO::AIO::poll_wait, IO::AIO::poll_cb
909 while IO::AIO::nreqs;
910
911=item IO::AIO::nready
912
913Returns the number of requests currently in the ready state (not yet
914executed).
915
916=item IO::AIO::npending
917
918Returns the number of requests currently in the pending state (executed,
919but not yet processed by poll_cb).
920
921=item IO::AIO::flush
922
923Wait till all outstanding AIO requests have been handled.
924
925Strictly equivalent to:
926
927 IO::AIO::poll_wait, IO::AIO::poll_cb
928 while IO::AIO::nreqs;
929
930=item IO::AIO::poll
931
932Waits until some requests have been handled.
933
934Strictly equivalent to:
935
936 IO::AIO::poll_wait, IO::AIO::poll_cb
937 if IO::AIO::nreqs;
938 1427
939=item IO::AIO::min_parallel $nthreads 1428=item IO::AIO::min_parallel $nthreads
940 1429
941Set the minimum number of AIO threads to C<$nthreads>. The current 1430Set the minimum number of AIO threads to C<$nthreads>. The current
942default is C<8>, which means eight asynchronous operations can execute 1431default is C<8>, which means eight asynchronous operations can execute
943concurrently at any one time (the number of outstanding requests, 1432concurrently at any one time (the number of outstanding requests,
944however, is unlimited). 1433however, is unlimited).
945 1434
946IO::AIO starts threads only on demand, when an AIO request is queued and 1435IO::AIO starts threads only on demand, when an AIO request is queued and
947no free thread exists. 1436no free thread exists. Please note that queueing up a hundred requests can
1437create demand for a hundred threads, even if it turns out that everything
1438is in the cache and could have been processed faster by a single thread.
948 1439
949It is recommended to keep the number of threads relatively low, as some 1440It is recommended to keep the number of threads relatively low, as some
950Linux kernel versions will scale negatively with the number of threads 1441Linux kernel versions will scale negatively with the number of threads
951(higher parallelity => MUCH higher latency). With current Linux 2.6 1442(higher parallelity => MUCH higher latency). With current Linux 2.6
952versions, 4-32 threads should be fine. 1443versions, 4-32 threads should be fine.
966This module automatically runs C<max_parallel 0> at program end, to ensure 1457This module automatically runs C<max_parallel 0> at program end, to ensure
967that all threads are killed and that there are no outstanding requests. 1458that all threads are killed and that there are no outstanding requests.
968 1459
969Under normal circumstances you don't need to call this function. 1460Under normal circumstances you don't need to call this function.
970 1461
1462=item IO::AIO::max_idle $nthreads
1463
1464Limit the number of threads (default: 4) that are allowed to idle (i.e.,
1465threads that did not get a request to process within 10 seconds). That
1466means if a thread becomes idle while C<$nthreads> other threads are also
1467idle, it will free its resources and exit.
1468
1469This is useful when you allow a large number of threads (e.g. 100 or 1000)
1470to allow for extremely high load situations, but want to free resources
1471under normal circumstances (1000 threads can easily consume 30MB of RAM).
1472
1473The default is probably ok in most situations, especially if thread
1474creation is fast. If thread creation is very slow on your system you might
1475want to use larger values.
1476
971=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs 1477=item IO::AIO::max_outstanding $maxreqs
972 1478
973This is a very bad function to use in interactive programs because it 1479This is a very bad function to use in interactive programs because it
974blocks, and a bad way to reduce concurrency because it is inexact: Better 1480blocks, and a bad way to reduce concurrency because it is inexact: Better
975use an C<aio_group> together with a feed callback. 1481use an C<aio_group> together with a feed callback.
976 1482
977Sets the maximum number of outstanding requests to C<$nreqs>. If you 1483Sets the maximum number of outstanding requests to C<$nreqs>. If you
978to queue up more than this number of requests, the next call to the 1484do queue up more than this number of requests, the next call to the
979C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>) 1485C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
980function will block until the limit is no longer exceeded. 1486function will block until the limit is no longer exceeded.
981 1487
982The default value is very large, so there is no practical limit on the 1488The default value is very large, so there is no practical limit on the
983number of outstanding requests. 1489number of outstanding requests.
984 1490
985You can still queue as many requests as you want. Therefore, 1491You can still queue as many requests as you want. Therefore,
986C<max_oustsanding> is mainly useful in simple scripts (with low values) or 1492C<max_outstanding> is mainly useful in simple scripts (with low values) or
987as a stop gap to shield against fatal memory overflow (with large values). 1493as a stop gap to shield against fatal memory overflow (with large values).
988 1494
989=back 1495=back
990 1496
1497=head3 STATISTICAL INFORMATION
1498
1499=over
1500
1501=item IO::AIO::nreqs
1502
1503Returns the number of requests currently in the ready, execute or pending
1504states (i.e. for which their callback has not been invoked yet).
1505
1506Example: wait till there are no outstanding requests anymore:
1507
1508 IO::AIO::poll_wait, IO::AIO::poll_cb
1509 while IO::AIO::nreqs;
1510
1511=item IO::AIO::nready
1512
1513Returns the number of requests currently in the ready state (not yet
1514executed).
1515
1516=item IO::AIO::npending
1517
1518Returns the number of requests currently in the pending state (executed,
1519but not yet processed by poll_cb).
1520
1521=back
1522
1523=head3 MISCELLANEOUS FUNCTIONS
1524
1525IO::AIO implements some functions that might be useful, but are not
1526asynchronous.
1527
1528=over 4
1529
1530=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1531
1532Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1533but is blocking (this makes most sense if you know the input data is
1534likely cached already and the output filehandle is set to non-blocking
1535operations).
1536
1537Returns the number of bytes copied, or C<-1> on error.
1538
1539=item IO::AIO::fadvise $fh, $offset, $len, $advice
1540
1541Simply calls the C<posix_fadvise> function (see it's
1542manpage for details). The following advice constants are
1543avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1544C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1545C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1546
1547On systems that do not implement C<posix_fadvise>, this function returns
1548ENOSYS, otherwise the return value of C<posix_fadvise>.
1549
1550=item IO::AIO::mlockall $flags
1551
1552Calls the C<mlockall> function with the given C<$flags> (a combination of
1553C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL__FUTURE>).
1554
1555On systems that do not implement C<mlockall>, this function returns
1556ENOSYS, otherwise the return value of C<mlockall>.
1557
1558=item IO::AIO::munlockall
1559
1560Calls the C<munlockall> function.
1561
1562On systems that do not implement C<munlockall>, this function returns
1563ENOSYS, otherwise the return value of C<munlockall>.
1564
1565=back
1566
991=cut 1567=cut
992 1568
993# support function to convert a fd into a perl filehandle
994sub _fd2fh {
995 return undef if $_[0] < 0;
996
997 # try to generate nice filehandles
998 my $sym = "IO::AIO::fd#$_[0]";
999 local *$sym;
1000
1001 open *$sym, "+<&=$_[0]" # usually works under any unix
1002 or open *$sym, "<&=$_[0]" # cygwin needs this
1003 or open *$sym, ">&=$_[0]" # or this
1004 or return undef;
1005
1006 *$sym
1007}
1008
1009min_parallel 8; 1569min_parallel 8;
1010 1570
1011END { 1571END { flush }
1012 min_parallel 1;
1013 flush;
1014};
1015 1572
10161; 15731;
1574
1575=head1 EVENT LOOP INTEGRATION
1576
1577It is recommended to use L<AnyEvent::AIO> to integrate IO::AIO
1578automatically into many event loops:
1579
1580 # AnyEvent integration (EV, Event, Glib, Tk, POE, urxvt, pureperl...)
1581 use AnyEvent::AIO;
1582
1583You can also integrate IO::AIO manually into many event loops, here are
1584some examples of how to do this:
1585
1586 # EV integration
1587 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
1588
1589 # Event integration
1590 Event->io (fd => IO::AIO::poll_fileno,
1591 poll => 'r',
1592 cb => \&IO::AIO::poll_cb);
1593
1594 # Glib/Gtk2 integration
1595 add_watch Glib::IO IO::AIO::poll_fileno,
1596 in => sub { IO::AIO::poll_cb; 1 };
1597
1598 # Tk integration
1599 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
1600 readable => \&IO::AIO::poll_cb);
1601
1602 # Danga::Socket integration
1603 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1604 \&IO::AIO::poll_cb);
1017 1605
1018=head2 FORK BEHAVIOUR 1606=head2 FORK BEHAVIOUR
1019 1607
1020This module should do "the right thing" when the process using it forks: 1608This module should do "the right thing" when the process using it forks:
1021 1609
1039bytes of memory. In addition, stat requests need a stat buffer (possibly 1627bytes of memory. In addition, stat requests need a stat buffer (possibly
1040a few hundred bytes), readdir requires a result buffer and so on. Perl 1628a few hundred bytes), readdir requires a result buffer and so on. Perl
1041scalars and other data passed into aio requests will also be locked and 1629scalars and other data passed into aio requests will also be locked and
1042will consume memory till the request has entered the done state. 1630will consume memory till the request has entered the done state.
1043 1631
1044This is now awfully much, so queuing lots of requests is not usually a 1632This is not awfully much, so queuing lots of requests is not usually a
1045problem. 1633problem.
1046 1634
1047Per-thread usage: 1635Per-thread usage:
1048 1636
1049In the execution phase, some aio requests require more memory for 1637In the execution phase, some aio requests require more memory for
1054 1642
1055Known bugs will be fixed in the next release. 1643Known bugs will be fixed in the next release.
1056 1644
1057=head1 SEE ALSO 1645=head1 SEE ALSO
1058 1646
1059L<Coro::AIO>. 1647L<AnyEvent::AIO> for easy integration into event loops, L<Coro::AIO> for a
1648more natural syntax.
1060 1649
1061=head1 AUTHOR 1650=head1 AUTHOR
1062 1651
1063 Marc Lehmann <schmorp@schmorp.de> 1652 Marc Lehmann <schmorp@schmorp.de>
1064 http://home.schmorp.de/ 1653 http://home.schmorp.de/

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