ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/IO-AIO/AIO.pm
(Generate patch)

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.9 by root, Sun Jul 10 22:20:55 2005 UTC vs.
Revision 1.27 by root, Tue Aug 16 22:22:18 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
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.
… …
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 = 1.1;
60 69
61 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 70 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
62 aio_fsync aio_fdatasync aio_readahead); 71 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); 72 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
64 73
65 require XSLoader; 74 require XSLoader;
66 XSLoader::load IO::AIO, $VERSION; 75 XSLoader::load IO::AIO, $VERSION;
67} 76}
… …
70 79
71=head2 AIO FUNCTIONS 80=head2 AIO FUNCTIONS
72 81
73All the C<aio_*> calls are more or less thin wrappers around the syscall 82All the C<aio_*> calls are more or less thin wrappers around the syscall
74with the same name (sans C<aio_>). The arguments are similar or identical, 83with the same name (sans C<aio_>). The arguments are similar or identical,
75and they all accept an additional C<$callback> argument which must be 84and they all accept an additional (and optional) C<$callback> argument
76a code reference. This code reference will get called with the syscall 85which 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 86the 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 87perl, which usually delivers "false") as it's sole argument when the given
79been executed asynchronously. 88syscall has been executed asynchronously.
80 89
81All functions that expect a filehandle will also accept a file descriptor. 90All functions expecting a filehandle keep a copy of the filehandle
91internally until the request has finished.
82 92
83The filenames you pass to these routines I<must> be absolute. The reason 93The filenames you pass to these routines I<must> be absolute. The reason
84is that at the time the request is being executed, the current working 94for this is that at the time the request is being executed, the current
85directory could have changed. Alternatively, you can make sure that you 95working directory could have changed. Alternatively, you can make sure
86never change the current working directory. 96that you never change the current working directory.
87 97
88=over 4 98=over 4
89 99
90=item aio_open $pathname, $flags, $mode, $callback 100=item aio_open $pathname, $flags, $mode, $callback
91 101
… …
93created filehandle for the file. 103created filehandle for the file.
94 104
95The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 105The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
96for an explanation. 106for an explanation.
97 107
98The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 108The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
99list. They are the same as used in C<sysopen>. 109list. They are the same as used by C<sysopen>.
110
111Likewise, C<$mode> specifies the mode of the newly created file, if it
112didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
113except that it is mandatory (i.e. use C<0> if you don't create new files,
114and C<0666> or C<0777> if you do).
100 115
101Example: 116Example:
102 117
103 aio_open "/etc/passwd", O_RDONLY, 0, sub { 118 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 if ($_[0]) { 119 if ($_[0]) {
… …
111 126
112=item aio_close $fh, $callback 127=item aio_close $fh, $callback
113 128
114Asynchronously close a file and call the callback with the result 129Asynchronously close a file and call the callback with the result
115code. I<WARNING:> although accepted, you should not pass in a perl 130code. I<WARNING:> although accepted, you should not pass in a perl
116filehandle here, as perl will likely close the file descriptor itself when 131filehandle here, as perl will likely close the file descriptor another
117the filehandle is destroyed. Normally, you can safely call perls C<close> 132time when the filehandle is destroyed. Normally, you can safely call perls
118or just let filehandles go out of scope. 133C<close> or just let filehandles go out of scope.
134
135This is supposed to be a bug in the API, so that might change. It's
136therefore best to avoid this function.
119 137
120=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 138=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
121 139
122=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 140=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
123 141
124Reads or writes C<length> bytes from the specified C<fh> and C<offset> 142Reads or writes C<length> bytes from the specified C<fh> and C<offset>
125into the scalar given by C<data> and offset C<dataoffset> and calls the 143into the scalar given by C<data> and offset C<dataoffset> and calls the
126callback without the actual number of bytes read (or -1 on error, just 144callback without the actual number of bytes read (or -1 on error, just
127like the syscall). 145like the syscall).
128 146
129Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 147Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
130offset C<0> within the scalar: 148offset C<0> within the scalar:
131 149
132 aio_read $fh, 7, 15, $buffer, 0, sub { 150 aio_read $fh, 7, 15, $buffer, 0, sub {
133 $_[0] > 0 or die "read error: $!"; 151 $_[0] > 0 or die "read error: $!";
134 print "read $_[0] bytes: <$buffer>\n"; 152 print "read $_[0] bytes: <$buffer>\n";
135 }; 153 };
136 154
137=item aio_readahead $fh,$offset,$length, $callback 155=item aio_readahead $fh,$offset,$length, $callback
138 156
139Asynchronously reads the specified byte range into the page cache, using
140the C<readahead> syscall. If that syscall doesn't exist the status will be
141C<-1> and C<$!> is set to ENOSYS.
142
143readahead() populates the page cache with data from a file so that 157C<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<$offset> 158subsequent reads from that file will not block on disk I/O. The C<$offset>
145argument specifies the starting point from which data is to be read and 159argument specifies the starting point from which data is to be read and
146C<$length> specifies the number of bytes to be read. I/O is performed in 160C<$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 161whole 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 162and 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 163(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. 164file. The current file offset of the file is left unchanged.
165
166If that syscall doesn't exist (likely if your OS isn't Linux) it will be
167emulated by simply reading the data, which would have a similar effect.
151 168
152=item aio_stat $fh_or_path, $callback 169=item aio_stat $fh_or_path, $callback
153 170
154=item aio_lstat $fh, $callback 171=item aio_lstat $fh, $callback
155 172
… …
174=item aio_unlink $pathname, $callback 191=item aio_unlink $pathname, $callback
175 192
176Asynchronously unlink (delete) a file and call the callback with the 193Asynchronously unlink (delete) a file and call the callback with the
177result code. 194result code.
178 195
196=item aio_rmdir $pathname, $callback
197
198Asynchronously rmdir (delete) a directory and call the callback with the
199result code.
200
179=item aio_fsync $fh, $callback 201=item aio_fsync $fh, $callback
180 202
181Asynchronously call fsync on the given filehandle and call the callback 203Asynchronously call fsync on the given filehandle and call the callback
182with the fsync result code. 204with the fsync result code.
183 205
184=item aio_fdatasync $fh, $callback 206=item aio_fdatasync $fh, $callback
185 207
186Asynchronously call fdatasync on the given filehandle and call the 208Asynchronously call fdatasync on the given filehandle and call the
187callback with the fdatasync result code. 209callback with the fdatasync result code.
188 210
211If this call isn't available because your OS lacks it or it couldn't be
212detected, it will be emulated by calling C<fsync> instead.
213
189=back 214=back
190 215
191=head2 SUPPORT FUNCTIONS 216=head2 SUPPORT FUNCTIONS
192 217
193=over 4 218=over 4
194 219
195=item $fileno = IO::AIO::poll_fileno 220=item $fileno = IO::AIO::poll_fileno
196 221
197Return the I<request result pipe filehandle>. This filehandle must be 222Return the I<request result pipe file descriptor>. This filehandle must be
198polled for reading by some mechanism outside this module (e.g. Event 223polled 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 224select, see below or the SYNOPSIS). If the pipe becomes readable you have
200C<poll_cb> to check the results. 225to call C<poll_cb> to check the results.
201 226
202See C<poll_cb> for an example. 227See C<poll_cb> for an example.
203 228
204=item IO::AIO::poll_cb 229=item IO::AIO::poll_cb
205 230
206Process all outstanding events on the result pipe. You have to call this 231Process all outstanding events on the result pipe. You have to call this
207regularly. Returns the number of events processed. Returns immediately 232regularly. Returns the number of events processed. Returns immediately
208when no events are outstanding. 233when no events are outstanding.
209 234
210You can use Event to multiplex, e.g.: 235Example: Install an Event watcher that automatically calls
236IO::AIO::poll_cb with high priority:
211 237
212 Event->io (fd => IO::AIO::poll_fileno, 238 Event->io (fd => IO::AIO::poll_fileno,
213 poll => 'r', async => 1, 239 poll => 'r', async => 1,
214 cb => \&IO::AIO::poll_cb); 240 cb => \&IO::AIO::poll_cb);
215 241
216=item IO::AIO::poll_wait 242=item IO::AIO::poll_wait
217 243
218Wait till the result filehandle becomes ready for reading (simply does a 244Wait till the result filehandle becomes ready for reading (simply does a
219select on the filehandle. This is useful if you want to synchronously wait 245C<select> on the filehandle. This is useful if you want to synchronously wait
220for some requests to finish). 246for some requests to finish).
221 247
222See C<nreqs> for an example. 248See C<nreqs> for an example.
223 249
224=item IO::AIO::nreqs 250=item IO::AIO::nreqs
225 251
226Returns the number of requests currently outstanding. 252Returns the number of requests currently outstanding (i.e. for which their
253callback has not been invoked yet).
227 254
228Example: wait till there are no outstanding requests anymore: 255Example: wait till there are no outstanding requests anymore:
229 256
230 IO::AIO::poll_wait, IO::AIO::poll_cb 257 IO::AIO::poll_wait, IO::AIO::poll_cb
231 while IO::AIO::nreqs; 258 while IO::AIO::nreqs;
259
260=item IO::AIO::flush
261
262Wait till all outstanding AIO requests have been handled.
263
264Strictly equivalent to:
265
266 IO::AIO::poll_wait, IO::AIO::poll_cb
267 while IO::AIO::nreqs;
268
269=item IO::AIO::poll
270
271Waits until some requests have been handled.
272
273Strictly equivalent to:
274
275 IO::AIO::poll_wait, IO::AIO::poll_cb
276 if IO::AIO::nreqs;
232 277
233=item IO::AIO::min_parallel $nthreads 278=item IO::AIO::min_parallel $nthreads
234 279
235Set the minimum number of AIO threads to C<$nthreads>. The default is 280Set 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 281C<1>, which means a single asynchronous operation can be done at one time
… …
274 319
275# support function to convert a fd into a perl filehandle 320# support function to convert a fd into a perl filehandle
276sub _fd2fh { 321sub _fd2fh {
277 return undef if $_[0] < 0; 322 return undef if $_[0] < 0;
278 323
279 # try to be perl5.6-compatible 324 # try to generate nice filehandles
280 local *AIO_FH; 325 my $sym = "IO::AIO::fd#$_[0]";
281 open AIO_FH, "+<&=$_[0]" 326 local *$sym;
327
328 open *$sym, "+<&=$_[0]" # usually works under any unix
329 or open *$sym, "<&=$_[0]" # cygwin needs this
330 or open *$sym, ">&=$_[0]" # or this
282 or return undef; 331 or return undef;
283 332
284 *AIO_FH 333 *$sym
285} 334}
286 335
287min_parallel 4; 336min_parallel 4;
288 337
289END { 338END {
290 max_parallel 0; 339 max_parallel 0;
291} 340}
292 341
2931; 3421;
294 343
344=head2 FORK BEHAVIOUR
345
346IO::AIO handles all outstanding AIO requests before the fork, destroys all
347AIO threads, and recreates them in both the parent and the child after the
348fork.
349
350
295=head1 SEE ALSO 351=head1 SEE ALSO
296 352
297L<Coro>, L<Linux::AIO>. 353L<Coro>, L<Linux::AIO>.
298 354
299=head1 AUTHOR 355=head1 AUTHOR

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines