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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.13 by root, Mon Jul 11 01:49:14 2005 UTC vs.
Revision 1.32 by root, Wed Aug 17 05:26:20 2005 UTC

… …
22 poll => 'r', 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 32
… …
48not well-supported (Linux doesn't allow them on normal files currently, 48not well-supported (Linux doesn't allow them on normal files currently,
49for 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
50remaining functionality would have to be implemented using threads anyway. 50remaining functionality would have to be implemented using threads anyway.
51 51
52Although 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
53currently 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.
54 56
55=cut 57=cut
56 58
57package IO::AIO; 59package IO::AIO;
58 60
61no warnings;
62
59use base 'Exporter'; 63use base 'Exporter';
60 64
61use Fcntl (); 65use Fcntl ();
62 66
63BEGIN { 67BEGIN {
64 $VERSION = 0.3; 68 $VERSION = 1.3;
69
65 70
66 @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
67 aio_fsync aio_fdatasync aio_readahead); 72 aio_rmdir aio_symlink aio_fsync aio_fdatasync aio_readahead);
68 @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);
69 74
70 require XSLoader; 75 require XSLoader;
71 XSLoader::load IO::AIO, $VERSION; 76 XSLoader::load IO::AIO, $VERSION;
72} 77}
… …
75 80
76=head2 AIO FUNCTIONS 81=head2 AIO FUNCTIONS
77 82
78All the C<aio_*> calls are more or less thin wrappers around the syscall 83All the C<aio_*> calls are more or less thin wrappers around the syscall
79with the same name (sans C<aio_>). The arguments are similar or identical, 84with the same name (sans C<aio_>). The arguments are similar or identical,
80and they all accept an additional C<$callback> argument which must be 85and they all accept an additional (and optional) C<$callback> argument
81a code reference. This code reference will get called with the syscall 86which must be a code reference. This code reference will get called with
82return 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
83usually 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
84been executed asynchronously. 89syscall has been executed asynchronously.
85 90
86All 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.
87 93
88The filenames you pass to these routines I<must> be absolute. The reason 94The pathnames you pass to these routines I<must> be absolute and
89is 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
90directory 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
91never 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.
92 106
93=over 4 107=over 4
94 108
95=item aio_open $pathname, $flags, $mode, $callback 109=item aio_open $pathname, $flags, $mode, $callback
96 110
… …
98created filehandle for the file. 112created filehandle for the file.
99 113
100The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 114The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
101for an explanation. 115for an explanation.
102 116
103The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 117The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
104list. They are the same as used in C<sysopen>. 118list. They are the same as used by C<sysopen>.
119
120Likewise, C<$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).
105 124
106Example: 125Example:
107 126
108 aio_open "/etc/passwd", O_RDONLY, 0, sub { 127 aio_open "/etc/passwd", O_RDONLY, 0, sub {
109 if ($_[0]) { 128 if ($_[0]) {
… …
116 135
117=item aio_close $fh, $callback 136=item aio_close $fh, $callback
118 137
119Asynchronously close a file and call the callback with the result 138Asynchronously close a file and call the callback with the result
120code. I<WARNING:> although accepted, you should not pass in a perl 139code. I<WARNING:> although accepted, you should not pass in a perl
121filehandle here, as perl will likely close the file descriptor itself when 140filehandle here, as perl will likely close the file descriptor another
122the filehandle is destroyed. Normally, you can safely call perls C<close> 141time when the filehandle is destroyed. Normally, you can safely call perls
123or 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.
124 146
125=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 147=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
126 148
127=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 149=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
128 150
129Reads or writes C<length> bytes from the specified C<fh> and C<offset> 151Reads or writes C<length> bytes from the specified C<fh> and C<offset>
130into the scalar given by C<data> and offset C<dataoffset> and calls the 152into the scalar given by C<data> and offset C<dataoffset> and calls the
131callback without the actual number of bytes read (or -1 on error, just 153callback without the actual number of bytes read (or -1 on error, just
132like the syscall). 154like the syscall).
133 155
156The C<$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
134Example: 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
135offset C<0> within the scalar: 161offset C<0> within the scalar:
136 162
137 aio_read $fh, 7, 15, $buffer, 0, sub { 163 aio_read $fh, 7, 15, $buffer, 0, sub {
138 $_[0] > 0 or die "read error: $!"; 164 $_[0] > 0 or die "read error: $!";
139 print "read $_[0] bytes: <$buffer>\n"; 165 print "read $_[0] bytes: <$buffer>\n";
140 }; 166 };
141 167
142=item aio_readahead $fh,$offset,$length, $callback 168=item aio_readahead $fh,$offset,$length, $callback
143 169
144Asynchronously reads the specified byte range into the page cache, using
145the C<readahead> syscall. If that syscall doesn't exist the status will be
146C<-1> and C<$!> is set to ENOSYS.
147
148readahead() 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
149subsequent 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>
150argument 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
151C<$length> specifies the number of bytes to be read. I/O is performed in 173C<$length> specifies the number of bytes to be read. I/O is performed in
152whole 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
153and 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
154(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
155file. 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.
156 181
157=item aio_stat $fh_or_path, $callback 182=item aio_stat $fh_or_path, $callback
158 183
159=item aio_lstat $fh, $callback 184=item aio_lstat $fh, $callback
160 185
… …
179=item aio_unlink $pathname, $callback 204=item aio_unlink $pathname, $callback
180 205
181Asynchronously unlink (delete) a file and call the callback with the 206Asynchronously unlink (delete) a file and call the callback with the
182result code. 207result code.
183 208
209=item aio_rmdir $pathname, $callback
210
211Asynchronously rmdir (delete) a directory and call the callback with the
212result code.
213
184=item aio_fsync $fh, $callback 214=item aio_fsync $fh, $callback
185 215
186Asynchronously call fsync on the given filehandle and call the callback 216Asynchronously call fsync on the given filehandle and call the callback
187with the fsync result code. 217with the fsync result code.
188 218
189=item aio_fdatasync $fh, $callback 219=item aio_fdatasync $fh, $callback
190 220
191Asynchronously call fdatasync on the given filehandle and call the 221Asynchronously call fdatasync on the given filehandle and call the
192callback with the fdatasync result code. 222callback with the fdatasync result code.
193 223
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
194=back 227=back
195 228
196=head2 SUPPORT FUNCTIONS 229=head2 SUPPORT FUNCTIONS
197 230
198=over 4 231=over 4
199 232
200=item $fileno = IO::AIO::poll_fileno 233=item $fileno = IO::AIO::poll_fileno
201 234
202Return the I<request result pipe filehandle>. This filehandle must be 235Return the I<request result pipe file descriptor>. This filehandle must be
203polled for reading by some mechanism outside this module (e.g. Event 236polled for reading by some mechanism outside this module (e.g. Event or
204or 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
205C<poll_cb> to check the results. 238to call C<poll_cb> to check the results.
206 239
207See C<poll_cb> for an example. 240See C<poll_cb> for an example.
208 241
209=item IO::AIO::poll_cb 242=item IO::AIO::poll_cb
210 243
211Process 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
212regularly. Returns the number of events processed. Returns immediately 245regularly. Returns the number of events processed. Returns immediately
213when no events are outstanding. 246when no events are outstanding.
214 247
215You can use Event to multiplex, e.g.: 248Example: Install an Event watcher that automatically calls
249IO::AIO::poll_cb with high priority:
216 250
217 Event->io (fd => IO::AIO::poll_fileno, 251 Event->io (fd => IO::AIO::poll_fileno,
218 poll => 'r', async => 1, 252 poll => 'r', async => 1,
219 cb => \&IO::AIO::poll_cb); 253 cb => \&IO::AIO::poll_cb);
220 254
221=item IO::AIO::poll_wait 255=item IO::AIO::poll_wait
222 256
223Wait till the result filehandle becomes ready for reading (simply does a 257Wait till the result filehandle becomes ready for reading (simply does a
224select 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
225for some requests to finish). 259for some requests to finish).
226 260
227See C<nreqs> for an example. 261See C<nreqs> for an example.
228 262
229=item IO::AIO::nreqs 263=item IO::AIO::nreqs
230 264
231Returns the number of requests currently outstanding. 265Returns the number of requests currently outstanding (i.e. for which their
266callback has not been invoked yet).
232 267
233Example: wait till there are no outstanding requests anymore: 268Example: wait till there are no outstanding requests anymore:
234 269
235 IO::AIO::poll_wait, IO::AIO::poll_cb 270 IO::AIO::poll_wait, IO::AIO::poll_cb
236 while IO::AIO::nreqs; 271 while IO::AIO::nreqs;
… …
297 332
298# support function to convert a fd into a perl filehandle 333# support function to convert a fd into a perl filehandle
299sub _fd2fh { 334sub _fd2fh {
300 return undef if $_[0] < 0; 335 return undef if $_[0] < 0;
301 336
302 # try to be perl5.6-compatible 337 # try to generate nice filehandles
303 local *AIO_FH; 338 my $sym = "IO::AIO::fd#$_[0]";
304 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
305 or return undef; 344 or return undef;
306 345
307 *AIO_FH 346 *$sym
308} 347}
309 348
310min_parallel 4; 349min_parallel 4;
311 350
312END { 351END {
313 max_parallel 0; 352 max_parallel 0;
314} 353}
315 354
3161; 3551;
317 356
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
318=head1 SEE ALSO 365=head1 SEE ALSO
319 366
320L<Coro>, L<Linux::AIO>. 367L<Coro>, L<Linux::AIO>.
321 368
322=head1 AUTHOR 369=head1 AUTHOR

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