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Revision 1.9 by root, Sun Jul 10 22:20:55 2005 UTC vs.
Revision 1.22 by root, Wed Jul 20 21:55:27 2005 UTC

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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.
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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
54use base 'Exporter'; 61use base 'Exporter';
55 62
56use Fcntl (); 63use Fcntl ();
57 64
58BEGIN { 65BEGIN {
59 $VERSION = 0.2; 66 $VERSION = 0.9;
60 67
61 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink 68 @EXPORT = qw(aio_read aio_write aio_open aio_close aio_stat aio_lstat aio_unlink
62 aio_fsync aio_fdatasync aio_readahead); 69 aio_fsync aio_fdatasync aio_readahead);
63 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs); 70 @EXPORT_OK = qw(poll_fileno poll_cb min_parallel max_parallel max_outstanding nreqs);
64 71
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70 77
71=head2 AIO FUNCTIONS 78=head2 AIO FUNCTIONS
72 79
73All the C<aio_*> calls are more or less thin wrappers around the syscall 80All the C<aio_*> calls are more or less thin wrappers around the syscall
74with the same name (sans C<aio_>). The arguments are similar or identical, 81with the same name (sans C<aio_>). The arguments are similar or identical,
75and they all accept an additional C<$callback> argument which must be 82and they all accept an additional (and optional) C<$callback> argument
76a code reference. This code reference will get called with the syscall 83which 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 84the 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 85perl, which usually delivers "false") as it's sole argument when the given
79been executed asynchronously. 86syscall has been executed asynchronously.
80 87
81All functions that expect a filehandle will also accept a file descriptor. 88All functions that expect a filehandle will also accept a file descriptor.
82 89
83The filenames you pass to these routines I<must> be absolute. The reason 90The 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 91for this is that at the time the request is being executed, the current
85directory could have changed. Alternatively, you can make sure that you 92working directory could have changed. Alternatively, you can make sure
86never change the current working directory. 93that you never change the current working directory.
87 94
88=over 4 95=over 4
89 96
90=item aio_open $pathname, $flags, $mode, $callback 97=item aio_open $pathname, $flags, $mode, $callback
91 98
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93created filehandle for the file. 100created filehandle for the file.
94 101
95The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 102The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
96for an explanation. 103for an explanation.
97 104
98The C<$mode> argument is a bitmask. See the C<Fcntl> module for a 105The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
99list. They are the same as used in C<sysopen>. 106list. They are the same as used by C<sysopen>.
107
108Likewise, C<$mode> specifies the mode of the newly created file, if it
109didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
110except that it is mandatory (i.e. use C<0> if you don't create new files,
111and C<0666> or C<0777> if you do).
100 112
101Example: 113Example:
102 114
103 aio_open "/etc/passwd", O_RDONLY, 0, sub { 115 aio_open "/etc/passwd", O_RDONLY, 0, sub {
104 if ($_[0]) { 116 if ($_[0]) {
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111 123
112=item aio_close $fh, $callback 124=item aio_close $fh, $callback
113 125
114Asynchronously close a file and call the callback with the result 126Asynchronously close a file and call the callback with the result
115code. I<WARNING:> although accepted, you should not pass in a perl 127code. I<WARNING:> although accepted, you should not pass in a perl
116filehandle here, as perl will likely close the file descriptor itself when 128filehandle here, as perl will likely close the file descriptor another
117the filehandle is destroyed. Normally, you can safely call perls C<close> 129time when the filehandle is destroyed. Normally, you can safely call perls
118or just let filehandles go out of scope. 130C<close> or just let filehandles go out of scope.
131
132This is supposed to be a bug in the API, so that might change. It's
133therefore best to avoid this function.
119 134
120=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback 135=item aio_read $fh,$offset,$length, $data,$dataoffset,$callback
121 136
122=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback 137=item aio_write $fh,$offset,$length, $data,$dataoffset,$callback
123 138
124Reads or writes C<length> bytes from the specified C<fh> and C<offset> 139Reads or writes C<length> bytes from the specified C<fh> and C<offset>
125into the scalar given by C<data> and offset C<dataoffset> and calls the 140into the scalar given by C<data> and offset C<dataoffset> and calls the
126callback without the actual number of bytes read (or -1 on error, just 141callback without the actual number of bytes read (or -1 on error, just
127like the syscall). 142like the syscall).
128 143
129Example: Read 15 bytes at offset 7 into scalar C<$buffer>, strating at 144Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
130offset C<0> within the scalar: 145offset C<0> within the scalar:
131 146
132 aio_read $fh, 7, 15, $buffer, 0, sub { 147 aio_read $fh, 7, 15, $buffer, 0, sub {
133 $_[0] > 0 or die "read error: $!"; 148 $_[0] > 0 or die "read error: $!";
134 print "read $_[0] bytes: <$buffer>\n"; 149 print "read $_[0] bytes: <$buffer>\n";
135 }; 150 };
136 151
137=item aio_readahead $fh,$offset,$length, $callback 152=item aio_readahead $fh,$offset,$length, $callback
138 153
139Asynchronously reads the specified byte range into the page cache, using 154Asynchronously reads the specified byte range into the page cache, using
140the C<readahead> syscall. If that syscall doesn't exist the status will be 155the C<readahead> syscall. If that syscall doesn't exist (likely if your OS
141C<-1> and C<$!> is set to ENOSYS. 156isn't Linux) the status will be C<-1> and C<$!> is set to C<ENOSYS>.
142 157
143readahead() populates the page cache with data from a file so that 158C<aio_readahead> populates the page cache with data from a file so that
144subsequent reads from that file will not block on disk I/O. The C<$offset> 159subsequent reads from that file will not block on disk I/O. The C<$offset>
145argument specifies the starting point from which data is to be read and 160argument specifies the starting point from which data is to be read and
146C<$length> specifies the number of bytes to be read. I/O is performed in 161C<$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 162whole 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 163and 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 164(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. 165file. The current file offset of the file is left unchanged.
151 166
152=item aio_stat $fh_or_path, $callback 167=item aio_stat $fh_or_path, $callback
153 168
154=item aio_lstat $fh, $callback 169=item aio_lstat $fh, $callback
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182with the fsync result code. 197with the fsync result code.
183 198
184=item aio_fdatasync $fh, $callback 199=item aio_fdatasync $fh, $callback
185 200
186Asynchronously call fdatasync on the given filehandle and call the 201Asynchronously call fdatasync on the given filehandle and call the
187callback with the fdatasync result code. 202callback with the fdatasync result code. Might set C<$!> to C<ENOSYS> if
203C<fdatasync> is not available.
188 204
189=back 205=back
190 206
191=head2 SUPPORT FUNCTIONS 207=head2 SUPPORT FUNCTIONS
192 208
193=over 4 209=over 4
194 210
195=item $fileno = IO::AIO::poll_fileno 211=item $fileno = IO::AIO::poll_fileno
196 212
197Return the I<request result pipe filehandle>. This filehandle must be 213Return the I<request result pipe file descriptor>. This filehandle must be
198polled for reading by some mechanism outside this module (e.g. Event 214polled 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 215select, see below or the SYNOPSIS). If the pipe becomes readable you have
200C<poll_cb> to check the results. 216to call C<poll_cb> to check the results.
201 217
202See C<poll_cb> for an example. 218See C<poll_cb> for an example.
203 219
204=item IO::AIO::poll_cb 220=item IO::AIO::poll_cb
205 221
206Process all outstanding events on the result pipe. You have to call this 222Process all outstanding events on the result pipe. You have to call this
207regularly. Returns the number of events processed. Returns immediately 223regularly. Returns the number of events processed. Returns immediately
208when no events are outstanding. 224when no events are outstanding.
209 225
210You can use Event to multiplex, e.g.: 226Example: Install an Event watcher that automatically calls
227IO::AIO::poll_cb with high priority:
211 228
212 Event->io (fd => IO::AIO::poll_fileno, 229 Event->io (fd => IO::AIO::poll_fileno,
213 poll => 'r', async => 1, 230 poll => 'r', async => 1,
214 cb => \&IO::AIO::poll_cb); 231 cb => \&IO::AIO::poll_cb);
215 232
216=item IO::AIO::poll_wait 233=item IO::AIO::poll_wait
217 234
218Wait till the result filehandle becomes ready for reading (simply does a 235Wait till the result filehandle becomes ready for reading (simply does a
219select on the filehandle. This is useful if you want to synchronously wait 236C<select> on the filehandle. This is useful if you want to synchronously wait
220for some requests to finish). 237for some requests to finish).
221 238
222See C<nreqs> for an example. 239See C<nreqs> for an example.
223 240
224=item IO::AIO::nreqs 241=item IO::AIO::nreqs
225 242
226Returns the number of requests currently outstanding. 243Returns the number of requests currently outstanding (i.e. for which their
244callback has not been invoked yet).
227 245
228Example: wait till there are no outstanding requests anymore: 246Example: wait till there are no outstanding requests anymore:
229 247
230 IO::AIO::poll_wait, IO::AIO::poll_cb 248 IO::AIO::poll_wait, IO::AIO::poll_cb
231 while IO::AIO::nreqs; 249 while IO::AIO::nreqs;
250
251=item IO::AIO::flush
252
253Wait till all outstanding AIO requests have been handled.
254
255Strictly equivalent to:
256
257 IO::AIO::poll_wait, IO::AIO::poll_cb
258 while IO::AIO::nreqs;
259
260=item IO::AIO::poll
261
262Waits until some requests have been handled.
263
264Strictly equivalent to:
265
266 IO::AIO::poll_wait, IO::AIO::poll_cb
267 if IO::AIO::nreqs;
232 268
233=item IO::AIO::min_parallel $nthreads 269=item IO::AIO::min_parallel $nthreads
234 270
235Set the minimum number of AIO threads to C<$nthreads>. The default is 271Set 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 272C<1>, which means a single asynchronous operation can be done at one time

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