| 1 |
=head1 NAME |
| 2 |
|
| 3 |
EV - perl interface to libevent, monkey.org/~provos/libevent/ |
| 4 |
|
| 5 |
=head1 SYNOPSIS |
| 6 |
|
| 7 |
use EV; |
| 8 |
|
| 9 |
# TIMER |
| 10 |
|
| 11 |
my $w = EV::timer 2, 0, sub { |
| 12 |
warn "is called after 2s"; |
| 13 |
}; |
| 14 |
|
| 15 |
my $w = EV::timer 2, 1, sub { |
| 16 |
warn "is called roughly every 2s (repeat = 1)"; |
| 17 |
}; |
| 18 |
|
| 19 |
undef $w; # destroy event watcher again |
| 20 |
|
| 21 |
my $w = EV::timer_abs 0, 60, sub { |
| 22 |
warn "is called every minute, on the minute, exactly"; |
| 23 |
}; |
| 24 |
|
| 25 |
# IO |
| 26 |
|
| 27 |
my $w = EV::io \*STDIN, EV::READ | EV::PERSIST, sub { |
| 28 |
my ($w, $events) = @_; # all callbacks get the watcher object and event mask |
| 29 |
if ($events & EV::TIMEOUT) { |
| 30 |
warn "nothing received on stdin for 10 seconds, retrying"; |
| 31 |
} else { |
| 32 |
warn "stdin is readable, you entered: ", <STDIN>; |
| 33 |
} |
| 34 |
}; |
| 35 |
$w->timeout (10); |
| 36 |
|
| 37 |
my $w = EV::timed_io \*STDIN, EV::READ, 30, sub { |
| 38 |
my ($w, $events) = @_; |
| 39 |
if ($_[1] & EV::TIMEOUT) { |
| 40 |
warn "nothing entered within 30 seconds, bye bye.\n"; |
| 41 |
$w->stop; |
| 42 |
} else { |
| 43 |
my $line = <STDIN>; |
| 44 |
warn "you entered something, you again have 30 seconds.\n"; |
| 45 |
} |
| 46 |
}; |
| 47 |
|
| 48 |
# SIGNALS |
| 49 |
|
| 50 |
my $w = EV::signal 'QUIT', sub { |
| 51 |
warn "sigquit received\n"; |
| 52 |
}; |
| 53 |
|
| 54 |
my $w = EV::signal 3, sub { |
| 55 |
warn "sigquit received (this is GNU/Linux, right?)\n"; |
| 56 |
}; |
| 57 |
|
| 58 |
# MAINLOOP |
| 59 |
EV::dispatch; # loop as long as watchers are active |
| 60 |
EV::loop; # the same thing |
| 61 |
EV::loop EV::LOOP_ONCE; # block until some events could be handles |
| 62 |
EV::loop EV::LOOP_NONBLOCK; # check and handle some events, but do not wait |
| 63 |
|
| 64 |
=head1 DESCRIPTION |
| 65 |
|
| 66 |
This module provides an interface to libevent |
| 67 |
(L<http://monkey.org/~provos/libevent/>). You probably should acquaint |
| 68 |
yourself with its documentation and source code to be able to use this |
| 69 |
module fully. |
| 70 |
|
| 71 |
Please note thta this module disables the libevent EPOLL method by |
| 72 |
default, see BUGS, below, if you need to enable it. |
| 73 |
|
| 74 |
=cut |
| 75 |
|
| 76 |
package EV; |
| 77 |
|
| 78 |
use strict; |
| 79 |
|
| 80 |
BEGIN { |
| 81 |
our $VERSION = '0.02'; |
| 82 |
use XSLoader; |
| 83 |
XSLoader::load "EV", $VERSION; |
| 84 |
} |
| 85 |
|
| 86 |
=head1 BASIC INTERFACE |
| 87 |
|
| 88 |
=over 4 |
| 89 |
|
| 90 |
=item $EV::NPRI |
| 91 |
|
| 92 |
How many priority levels are available. |
| 93 |
|
| 94 |
=item $EV::DIED |
| 95 |
|
| 96 |
Must contain a reference to a function that is called when a callback |
| 97 |
throws an exception (with $@ containing thr error). The default prints an |
| 98 |
informative message and continues. |
| 99 |
|
| 100 |
If this callback throws an exception it will be silently ignored. |
| 101 |
|
| 102 |
=item $time = EV::now |
| 103 |
|
| 104 |
Returns the time in (fractional) seconds since the epoch. |
| 105 |
|
| 106 |
=item $version = EV::version |
| 107 |
|
| 108 |
=item $method = EV::method |
| 109 |
|
| 110 |
Return version string and event polling method used. |
| 111 |
|
| 112 |
=item EV::loop $flags # EV::LOOP_ONCE, EV::LOOP_ONESHOT |
| 113 |
|
| 114 |
=item EV::loopexit $after |
| 115 |
|
| 116 |
Exit any active loop or dispatch after C<$after> seconds or immediately if |
| 117 |
C<$after> is missing or zero. |
| 118 |
|
| 119 |
=item EV::dispatch |
| 120 |
|
| 121 |
Same as C<EV::loop 0>. |
| 122 |
|
| 123 |
=item EV::event $callback |
| 124 |
|
| 125 |
Creates a new event watcher waiting for nothing, calling the given callback. |
| 126 |
|
| 127 |
=item my $w = EV::io $fileno_or_fh, $eventmask, $callback |
| 128 |
|
| 129 |
=item my $w = EV::io_ns $fileno_or_fh, $eventmask, $callback |
| 130 |
|
| 131 |
As long as the returned watcher object is alive, call the C<$callback> |
| 132 |
when the events specified in C<$eventmask> happen. Initially, the timeout |
| 133 |
is disabled. |
| 134 |
|
| 135 |
You can additionall set a timeout to occur on the watcher, but note that |
| 136 |
this timeout will not be reset when you get an I/O event in the EV::PERSIST |
| 137 |
case, and reaching a timeout will always stop the watcher even in the |
| 138 |
EV::PERSIST case. |
| 139 |
|
| 140 |
If you want a timeout to occur only after a specific time of inactivity, set |
| 141 |
a repeating timeout and do NOT use EV::PERSIST. |
| 142 |
|
| 143 |
Eventmask can be one or more of these constants ORed together: |
| 144 |
|
| 145 |
EV::READ wait until read() wouldn't block anymore |
| 146 |
EV::WRITE wait until write() wouldn't block anymore |
| 147 |
EV::PERSIST stay active after a (non-timeout) event occured |
| 148 |
|
| 149 |
The C<io_ns> variant doesn't add/start the newly created watcher. |
| 150 |
|
| 151 |
=item my $w = EV::timed_io $fileno_or_fh, $eventmask, $timeout, $callback |
| 152 |
|
| 153 |
=item my $w = EV::timed_io_ns $fileno_or_fh, $eventmask, $timeout, $callback |
| 154 |
|
| 155 |
Same as C<io> and C<io_ns>, but also specifies a timeout (as if there was |
| 156 |
a call to C<< $w->timeout ($timout, 1) >>. The persist flag is not allowed |
| 157 |
and will automatically be cleared. The watcher will be restarted after each event. |
| 158 |
|
| 159 |
If the timeout is zero or undef, no timeout will be set, and a normal |
| 160 |
watcher (with the persist flag set!) will be created. |
| 161 |
|
| 162 |
This has the effect of timing out after the specified period of inactivity |
| 163 |
has happened. |
| 164 |
|
| 165 |
Due to the design of libevent, this is also relatively inefficient, having |
| 166 |
one or two io watchers and a separate timeout watcher that you reset on |
| 167 |
activity (by calling its C<start> method) is usually more efficient. |
| 168 |
|
| 169 |
=item my $w = EV::timer $after, $repeat, $callback |
| 170 |
|
| 171 |
=item my $w = EV::timer_ns $after, $repeat, $callback |
| 172 |
|
| 173 |
Calls the callback after C<$after> seconds. If C<$repeat> is true, the |
| 174 |
timer will be restarted after the callback returns. This means that the |
| 175 |
callback would be called roughly every C<$after> seconds, prolonged by the |
| 176 |
time the callback takes. |
| 177 |
|
| 178 |
The C<timer_ns> variant doesn't add/start the newly created watcher. |
| 179 |
|
| 180 |
=item my $w = EV::timer_abs $at, $interval, $callback |
| 181 |
|
| 182 |
=item my $w = EV::timer_abs_ns $at, $interval, $callback |
| 183 |
|
| 184 |
Similar to EV::timer, but the time is given as an absolute point in time |
| 185 |
(C<$at>), plus an optional C<$interval>. |
| 186 |
|
| 187 |
If the C<$interval> is zero, then the callback will be called at the time |
| 188 |
C<$at> if that is in the future, or as soon as possible if its in the |
| 189 |
past. It will not automatically repeat. |
| 190 |
|
| 191 |
If the C<$interval> is nonzero, then the watcher will always be scheduled |
| 192 |
to time out at the next C<$at + integer * $interval> time. |
| 193 |
|
| 194 |
This can be used to schedule a callback to run at very regular intervals, |
| 195 |
as long as the processing time is less then the interval (otherwise |
| 196 |
obviously events will be skipped). |
| 197 |
|
| 198 |
Another way to think about it (for the mathematically inclined) is that |
| 199 |
C<timer_abs> will try to tun the callback at the next possible time where |
| 200 |
C<$time = $at (mod $interval)>, regardless of any time jumps. |
| 201 |
|
| 202 |
The C<timer_abs_ns> variant doesn't add/start the newly created watcher. |
| 203 |
|
| 204 |
=item my $w = EV::signal $signal, $callback |
| 205 |
|
| 206 |
=item my $w = EV::signal_ns $signal, $callback |
| 207 |
|
| 208 |
Call the callback when $signal is received (the signal can be specified |
| 209 |
by number or by name, just as with kill or %SIG). Signal watchers are |
| 210 |
persistent no natter what. |
| 211 |
|
| 212 |
EV will grab the signal for the process (the kernel only allows one |
| 213 |
component to receive signals) when you start a signal watcher, and |
| 214 |
removes it again when you stop it. Pelr does the same when you add/remove |
| 215 |
callbacks to %SIG, so watch out. |
| 216 |
|
| 217 |
Unfortunately, only one handler can be registered per signal. Screw |
| 218 |
libevent. |
| 219 |
|
| 220 |
The C<signal_ns> variant doesn't add/start the newly created watcher. |
| 221 |
|
| 222 |
=back |
| 223 |
|
| 224 |
=head1 THE EV::Event CLASS |
| 225 |
|
| 226 |
All EV functions creating an event watcher (designated by C<my $w => |
| 227 |
above) support the following methods on the returned watcher object: |
| 228 |
|
| 229 |
=over 4 |
| 230 |
|
| 231 |
=item $w->add ($timeout) |
| 232 |
|
| 233 |
Stops and (re-)starts the event watcher, setting the optional timeout to |
| 234 |
the given value, or clearing the timeout if none is given. |
| 235 |
|
| 236 |
=item $w->start |
| 237 |
|
| 238 |
Stops and (re-)starts the event watcher without touching the timeout. |
| 239 |
|
| 240 |
=item $w->del |
| 241 |
|
| 242 |
=item $w->stop |
| 243 |
|
| 244 |
Stop the event watcher if it was started. |
| 245 |
|
| 246 |
=item $current_callback = $w->cb |
| 247 |
|
| 248 |
=item $old_callback = $w->cb ($new_callback) |
| 249 |
|
| 250 |
Return the previously set callback and optionally set a new one. |
| 251 |
|
| 252 |
=item $current_fh = $w->fh |
| 253 |
|
| 254 |
=item $old_fh = $w->fh ($new_fh) |
| 255 |
|
| 256 |
Returns the previously set filehandle and optionally set a new one (also |
| 257 |
clears the EV::SIGNAL flag when setting a filehandle). |
| 258 |
|
| 259 |
=item $current_signal = $w->signal |
| 260 |
|
| 261 |
=item $old_signal = $w->signal ($new_signal) |
| 262 |
|
| 263 |
Returns the previously set signal number and optionally set a new one (also sets |
| 264 |
the EV::SIGNAL flag when setting a signal). |
| 265 |
|
| 266 |
=item $current_eventmask = $w->events |
| 267 |
|
| 268 |
=item $old_eventmask = $w->events ($new_eventmask) |
| 269 |
|
| 270 |
Returns the previously set event mask and optionally set a new one. |
| 271 |
|
| 272 |
=item $w->timeout ($after, $repeat) |
| 273 |
|
| 274 |
Resets the timeout (see C<EV::timer> for details). |
| 275 |
|
| 276 |
=item $w->timeout_abs ($at, $interval) |
| 277 |
|
| 278 |
Resets the timeout (see C<EV::timer_abs> for details). |
| 279 |
|
| 280 |
=item $w->priority_set ($priority) |
| 281 |
|
| 282 |
Set the priority of the watcher to C<$priority> (0 <= $priority < $EV::NPRI). |
| 283 |
|
| 284 |
=back |
| 285 |
|
| 286 |
=head1 BUGS |
| 287 |
|
| 288 |
Lots. Libevent itself isn't well tested and rather buggy, and this module |
| 289 |
is quite new at the moment. |
| 290 |
|
| 291 |
Please note that the epoll method is not, in general, reliable in programs |
| 292 |
that use fork (even if no libveent calls are being made in the forked |
| 293 |
process). If your program behaves erratically, try setting the environment |
| 294 |
variable C<EVENT_NOEPOLL> first when running the program. |
| 295 |
|
| 296 |
In general, if you fork, then you can only use the EV module in one of the |
| 297 |
children. |
| 298 |
|
| 299 |
=cut |
| 300 |
|
| 301 |
our $DIED = sub { |
| 302 |
warn "EV: error in callback (ignoring): $@"; |
| 303 |
}; |
| 304 |
|
| 305 |
our $NPRI = 4; |
| 306 |
our $BASE = init; |
| 307 |
priority_init $NPRI; |
| 308 |
|
| 309 |
push @AnyEvent::REGISTRY, [EV => "EV::AnyEvent"]; |
| 310 |
|
| 311 |
1; |
| 312 |
|
| 313 |
=head1 SEE ALSO |
| 314 |
|
| 315 |
L<EV::DNS>, L<event(3)>, L<event.h>, L<evdns.h>. |
| 316 |
L<EV::AnyEvent>. |
| 317 |
|
| 318 |
=head1 AUTHOR |
| 319 |
|
| 320 |
Marc Lehmann <schmorp@schmorp.de> |
| 321 |
http://home.schmorp.de/ |
| 322 |
|
| 323 |
=cut |
| 324 |
|
