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Revision 1.6 by root, Sun Jul 10 22:19:48 2005 UTC vs.
Revision 1.32 by root, Wed Aug 17 05:26:20 2005 UTC

… …
12 }; 12 };
13 13
14 aio_unlink "/tmp/file", sub { }; 14 aio_unlink "/tmp/file", sub { };
15 15
16 aio_read $fh, 30000, 1024, $buffer, 0, sub { 16 aio_read $fh, 30000, 1024, $buffer, 0, sub {
17 $_[0] >= 0 or die "read error: $!"; 17 $_[0] > 0 or die "read error: $!";
18 }; 18 };
19 19
20 # Event 20 # Event
21 Event->io (fd => IO::AIO::poll_fileno, 21 Event->io (fd => IO::AIO::poll_fileno,
22 poll => 'r', async => 1, 22 poll => 'r',
23 cb => \&IO::AIO::poll_cb); 23 cb => \&IO::AIO::poll_cb);
24 24
25 # Glib/Gtk2 25 # Glib/Gtk2
26 add_watch Glib::IO IO::AIO::poll_fileno, 26 add_watch Glib::IO IO::AIO::poll_fileno,
27 \&IO::AIO::poll_cb; 27 in => sub { IO::AIO::poll_cb; 1 };
28 28
29 # Tk 29 # Tk
30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "", 30 Tk::Event::IO->fileevent (IO::AIO::poll_fileno, "",
31 readable => \&IO::AIO::poll_cb); 31 readable => \&IO::AIO::poll_cb);
32
33 # Danga::Socket
34 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
35 \&IO::AIO::poll_cb);
36
32 37
33=head1 DESCRIPTION 38=head1 DESCRIPTION
34 39
35This module implements asynchronous I/O using whatever means your 40This module implements asynchronous I/O using whatever means your
36operating system supports. 41operating system supports.
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43not well-supported (Linux doesn't allow them on normal files currently, 48not well-supported (Linux doesn't allow them on normal files currently,
44for example), and they would only support aio_read and aio_write, so the 49for example), and they would only support aio_read and aio_write, so the
45remaining functionality would have to be implemented using threads anyway. 50remaining functionality would have to be implemented using threads anyway.
46 51
47Although the module will work with in the presence of other threads, it is 52Although the module will work with in the presence of other threads, it is
48currently not reentrant, so use appropriate locking yourself. 53currently not reentrant, so use appropriate locking yourself, always call
54C<poll_cb> from within the same thread, or never call C<poll_cb> (or other
55C<aio_> functions) recursively.
49 56
50=cut 57=cut
51 58
52package IO::AIO; 59package IO::AIO;
53 60
61no warnings;
62
54use base 'Exporter'; 63use base 'Exporter';
55 64
56use Fcntl (); 65use Fcntl ();
57 66
58BEGIN { 67BEGIN {
59 $VERSION = 0.2; 68 $VERSION = 1.3;
69
60 70
61 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 71 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
62 aio_fsync aio_fdatasync aio_readahead); 72 aio_rmdir aio_symlink aio_fsync aio_fdatasync aio_readahead);
63 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); 73 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
64 74
65 require XSLoader; 75 require XSLoader;
66 XSLoader::load IO::AIO, $VERSION; 76 XSLoader::load IO::AIO, $VERSION;
67} 77}
… …
70 80
71=head2 AIO FUNCTIONS 81=head2 AIO FUNCTIONS
72 82
73All the C<aio_*> calls are more or less thin wrappers around the syscall 83All the C<aio_*> calls are more or less thin wrappers around the syscall
74with the same name (sans C<aio_>). The arguments are similar or identical, 84with the same name (sans C<aio_>). The arguments are similar or identical,
75and they all accept an additional C<$callback> argument which must be 85and they all accept an additional (and optional) C<$callback> argument
76a code reference. This code reference will get called with the syscall 86which must be a code reference. This code reference will get called with
77return code (e.g. most syscalls return C<-1> on error, unlike perl, which 87the syscall return code (e.g. most syscalls return C<-1> on error, unlike
78usually delivers "false") as it's sole argument when the given syscall has 88perl, which usually delivers "false") as it's sole argument when the given
79been executed asynchronously. 89syscall has been executed asynchronously.
80 90
81All functions that expect a filehandle will also accept a file descriptor. 91All functions expecting a filehandle keep a copy of the filehandle
92internally until the request has finished.
82 93
83The filenames you pass to these routines I<must> be absolute. The reason 94The pathnames you pass to these routines I<must> be absolute and
84is that at the time the request is being executed, the current working 95encoded in byte form. The reason for the former is that at the time the
85directory could have changed. Alternatively, you can make sure that you 96request is being executed, the current working directory could have
97changed. Alternatively, you can make sure that you never change the
86never change the current working directory. 98current working directory.
99
100To encode pathnames to byte form, either make sure you either: a)
101always pass in filenames you got from outside (command line, readdir
102etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode
103your pathnames to the locale (or other) encoding in effect in the user
104environment, d) use Glib::filename_from_unicode on unicode filenames or e)
105use something else.
87 106
88=over 4 107=over 4
89 108
90=item aio_open $pathname, $flags, $mode, $callback 109=item aio_open $pathname, $flags, $mode, $callback
91 110
… …
93created filehandle for the file. 112created filehandle for the file.
94 113
95The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 114The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
96for an explanation. 115for an explanation.
97 116
98The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 117The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
99list. They are the same as used in C<sysopen>. 118list. They are the same as used by C<sysopen>.
119
120Likewise, C<$mode> specifies the mode of the newly created file, if it
121didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
122except that it is mandatory (i.e. use C<0> if you don't create new files,
123and C<0666> or C<0777> if you do).
100 124
101Example: 125Example:
102 126
103 aio_open "/etc/passwd", O_RDONLY, 0, sub { 127 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 if ($_[0]) { 128 if ($_[0]) {
… …
111 135
112=item aio_close $fh, $callback 136=item aio_close $fh, $callback
113 137
114Asynchronously close a file and call the callback with the result 138Asynchronously close a file and call the callback with the result
115code. I<WARNING:> although accepted, you should not pass in a perl 139code. I<WARNING:> although accepted, you should not pass in a perl
116filehandle here, as perl will likely close the file descriptor itself when 140filehandle here, as perl will likely close the file descriptor another
117the filehandle is destroyed. Normally, you can safely call perls C<close> 141time when the filehandle is destroyed. Normally, you can safely call perls
118or just let filehandles go out of scope. 142C<close> or just let filehandles go out of scope.
143
144This is supposed to be a bug in the API, so that might change. It's
145therefore best to avoid this function.
119 146
120=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 147=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
121 148
122=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 149=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
123 150
124Reads or writes C<length> bytes from the specified C<fh> and C<offset> 151Reads or writes C<length> bytes from the specified C<fh> and C<offset>
125into the scalar given by C<data> and offset C<dataoffset> and calls the 152into the scalar given by C<data> and offset C<dataoffset> and calls the
126callback without the actual number of bytes read (or -1 on error, just 153callback without the actual number of bytes read (or -1 on error, just
127like the syscall). 154like the syscall).
128 155
156The C<$data> scalar I<MUST NOT> be modified in any way while the request
157is outstanding. Modifying it can result in segfaults or WW3 (if the
158necessary/optional hardware is installed).
159
129Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 160Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
130offset C<0> within the scalar: 161offset C<0> within the scalar:
131 162
132 aio_read $fh, 7, 15, $buffer, 0, sub { 163 aio_read $fh, 7, 15, $buffer, 0, sub {
133 $_[0] >= 0 or die "read error: $!"; 164 $_[0] > 0 or die "read error: $!";
134 print "read <$buffer>\n"; 165 print "read $_[0] bytes: <$buffer>\n";
135 }; 166 };
136 167
137=item aio_readahead $fh,$offset,$length, $callback 168=item aio_readahead $fh,$offset,$length, $callback
138 169
139Asynchronously reads the specified byte range into the page cache, using
140the C<readahead> syscall. If that syscall doesn't exist the status will be
141C<-1> and C<$!> is set to ENOSYS.
142
143readahead() populates the page cache with data from a file so that 170C<aio_readahead> populates the page cache with data from a file so that
144subsequent reads from that file will not block on disk I/O. The C<$offset> 171subsequent reads from that file will not block on disk I/O. The C<$offset>
145argument specifies the starting point from which data is to be read and 172argument specifies the starting point from which data is to be read and
146C<$length> specifies the number of bytes to be read. I/O is performed in 173C<$length> specifies the number of bytes to be read. I/O is performed in
147whole pages, so that offset is effectively rounded down to a page boundary 174whole pages, so that offset is effectively rounded down to a page boundary
148and bytes are read up to the next page boundary greater than or equal to 175and bytes are read up to the next page boundary greater than or equal to
149(off-set+length). aio_readahead() does not read beyond the end of the 176(off-set+length). C<aio_readahead> does not read beyond the end of the
150file. The current file offset of the file is left unchanged. 177file. The current file offset of the file is left unchanged.
178
179If that syscall doesn't exist (likely if your OS isn't Linux) it will be
180emulated by simply reading the data, which would have a similar effect.
151 181
152=item aio_stat $fh_or_path, $callback 182=item aio_stat $fh_or_path, $callback
153 183
154=item aio_lstat $fh, $callback 184=item aio_lstat $fh, $callback
155 185
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174=item aio_unlink $pathname, $callback 204=item aio_unlink $pathname, $callback
175 205
176Asynchronously unlink (delete) a file and call the callback with the 206Asynchronously unlink (delete) a file and call the callback with the
177result code. 207result code.
178 208
209=item aio_rmdir $pathname, $callback
210
211Asynchronously rmdir (delete) a directory and call the callback with the
212result code.
213
179=item aio_fsync $fh, $callback 214=item aio_fsync $fh, $callback
180 215
181Asynchronously call fsync on the given filehandle and call the callback 216Asynchronously call fsync on the given filehandle and call the callback
182with the fsync result code. 217with the fsync result code.
183 218
184=item aio_fdatasync $fh, $callback 219=item aio_fdatasync $fh, $callback
185 220
186Asynchronously call fdatasync on the given filehandle and call the 221Asynchronously call fdatasync on the given filehandle and call the
187callback with the fdatasync result code. 222callback with the fdatasync result code.
188 223
224If this call isn't available because your OS lacks it or it couldn't be
225detected, it will be emulated by calling C<fsync> instead.
226
189=back 227=back
190 228
191=head2 SUPPORT FUNCTIONS 229=head2 SUPPORT FUNCTIONS
192 230
193=over 4 231=over 4
194 232
195=item $fileno = IO::AIO::poll_fileno 233=item $fileno = IO::AIO::poll_fileno
196 234
197Return the I<request result pipe filehandle>. This filehandle must be 235Return the I<request result pipe file descriptor>. This filehandle must be
198polled for reading by some mechanism outside this module (e.g. Event 236polled for reading by some mechanism outside this module (e.g. Event or
199or select, see below). If the pipe becomes readable you have to call 237select, see below or the SYNOPSIS). If the pipe becomes readable you have
200C<poll_cb> to check the results. 238to call C<poll_cb> to check the results.
201 239
202See C<poll_cb> for an example. 240See C<poll_cb> for an example.
203 241
204=item IO::AIO::poll_cb 242=item IO::AIO::poll_cb
205 243
206Process all outstanding events on the result pipe. You have to call this 244Process all outstanding events on the result pipe. You have to call this
207regularly. Returns the number of events processed. Returns immediately 245regularly. Returns the number of events processed. Returns immediately
208when no events are outstanding. 246when no events are outstanding.
209 247
210You can use Event to multiplex, e.g.: 248Example: Install an Event watcher that automatically calls
249IO::AIO::poll_cb with high priority:
211 250
212 Event->io (fd => IO::AIO::poll_fileno, 251 Event->io (fd => IO::AIO::poll_fileno,
213 poll => 'r', async => 1, 252 poll => 'r', async => 1,
214 cb => \&IO::AIO::poll_cb); 253 cb => \&IO::AIO::poll_cb);
215 254
216=item IO::AIO::poll_wait 255=item IO::AIO::poll_wait
217 256
218Wait till the result filehandle becomes ready for reading (simply does a 257Wait till the result filehandle becomes ready for reading (simply does a
219select on the filehandle. This is useful if you want to synchronously wait 258C<select> on the filehandle. This is useful if you want to synchronously wait
220for some requests to finish). 259for some requests to finish).
221 260
222See C<nreqs> for an example. 261See C<nreqs> for an example.
223 262
224=item IO::AIO::nreqs 263=item IO::AIO::nreqs
225 264
226Returns the number of requests currently outstanding. 265Returns the number of requests currently outstanding (i.e. for which their
266callback has not been invoked yet).
227 267
228Example: wait till there are no outstanding requests anymore: 268Example: wait till there are no outstanding requests anymore:
229 269
230 IO::AIO::poll_wait, IO::AIO::poll_cb 270 IO::AIO::poll_wait, IO::AIO::poll_cb
231 while IO::AIO::nreqs; 271 while IO::AIO::nreqs;
272
273=item IO::AIO::flush
274
275Wait till all outstanding AIO requests have been handled.
276
277Strictly equivalent to:
278
279 IO::AIO::poll_wait, IO::AIO::poll_cb
280 while IO::AIO::nreqs;
281
282=item IO::AIO::poll
283
284Waits until some requests have been handled.
285
286Strictly equivalent to:
287
288 IO::AIO::poll_wait, IO::AIO::poll_cb
289 if IO::AIO::nreqs;
232 290
233=item IO::AIO::min_parallel $nthreads 291=item IO::AIO::min_parallel $nthreads
234 292
235Set the minimum number of AIO threads to C<$nthreads>. The default is 293Set the minimum number of AIO threads to C<$nthreads>. The default is
236C<1>, which means a single asynchronous operation can be done at one time 294C<1>, which means a single asynchronous operation can be done at one time
… …
274 332
275# support function to convert a fd into a perl filehandle 333# support function to convert a fd into a perl filehandle
276sub _fd2fh { 334sub _fd2fh {
277 return undef if $_[0] < 0; 335 return undef if $_[0] < 0;
278 336
279 # try to be perl5.6-compatible 337 # try to generate nice filehandles
280 local *AIO_FH; 338 my $sym = "IO::AIO::fd#$_[0]";
281 open AIO_FH, "+<&=$_[0]" 339 local *$sym;
340
341 open *$sym, "+<&=$_[0]" # usually works under any unix
342 or open *$sym, "<&=$_[0]" # cygwin needs this
343 or open *$sym, ">&=$_[0]" # or this
282 or return undef; 344 or return undef;
283 345
284 *AIO_FH 346 *$sym
285} 347}
286 348
287min_parallel 4; 349min_parallel 4;
288 350
289END { 351END {
290 max_parallel 0; 352 max_parallel 0;
291} 353}
292 354
2931; 3551;
294 356
357=head2 FORK BEHAVIOUR
358
359Before the fork IO::AIO enters a quiescent state where no requests can be
360added in other threads and no results will be processed. After the fork
361the parent simply leaves the quiescent state and continues request/result
362processing, while the child clears the request/result queue and starts the
363same number of threads as were in use by the parent.
364
295=head1 SEE ALSO 365=head1 SEE ALSO
296 366
297L<Coro>, L<Linux::AIO>. 367L<Coro>, L<Linux::AIO>.
298 368
299=head1 AUTHOR 369=head1 AUTHOR

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