ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/AnyEvent/lib/AnyEvent.pm
(Generate patch)

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.184 by root, Wed Oct 1 16:53:27 2008 UTC vs.
Revision 1.196 by root, Thu Mar 26 07:47:42 2009 UTC

… …
136 136
137These watchers are normal Perl objects with normal Perl lifetime. After 137These watchers are normal Perl objects with normal Perl lifetime. After
138creating a watcher it will immediately "watch" for events and invoke the 138creating a watcher it will immediately "watch" for events and invoke the
139callback when the event occurs (of course, only when the event model 139callback when the event occurs (of course, only when the event model
140is in control). 140is in control).
141
142Note that B<callbacks must not permanently change global variables>
143potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
144callbacks must not C<die> >>. The former is good programming practise in
145Perl and the latter stems from the fact that exception handling differs
146widely between event loops.
141 147
142To disable the watcher you have to destroy it (e.g. by setting the 148To disable the watcher you have to destroy it (e.g. by setting the
143variable you store it in to C<undef> or otherwise deleting all references 149variable you store it in to C<undef> or otherwise deleting all references
144to it). 150to it).
145 151
… …
861no warnings; 867no warnings;
862use strict qw(vars subs); 868use strict qw(vars subs);
863 869
864use Carp; 870use Carp;
865 871
866our $VERSION = 4.3; 872our $VERSION = 4.341;
867our $MODEL; 873our $MODEL;
868 874
869our $AUTOLOAD; 875our $AUTOLOAD;
870our @ISA; 876our @ISA;
871 877
… …
1004# to support binding more than one watcher per filehandle (they usually 1010# to support binding more than one watcher per filehandle (they usually
1005# allow only one watcher per fd, so we dup it to get a different one). 1011# allow only one watcher per fd, so we dup it to get a different one).
1006sub _dupfh($$$$) { 1012sub _dupfh($$$$) {
1007 my ($poll, $fh, $r, $w) = @_; 1013 my ($poll, $fh, $r, $w) = @_;
1008 1014
1009 require Fcntl;
1010
1011 # cygwin requires the fh mode to be matching, unix doesn't 1015 # cygwin requires the fh mode to be matching, unix doesn't
1012 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1016 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1013 : $poll eq "w" ? ($w, ">") 1017 : $poll eq "w" ? ($w, ">")
1014 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'"; 1018 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1015 1019
… …
1043 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1047 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1044} 1048}
1045 1049
1046# default implementation for ->signal 1050# default implementation for ->signal
1047 1051
1048our %SIG_CB; 1052our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1053
1054sub _signal_exec {
1055 while (%SIG_EV) {
1056 sysread $SIGPIPE_R, my $dummy, 4;
1057 for (keys %SIG_EV) {
1058 delete $SIG_EV{$_};
1059 $_->() for values %{ $SIG_CB{$_} || {} };
1060 }
1061 }
1062}
1049 1063
1050sub signal { 1064sub signal {
1051 my (undef, %arg) = @_; 1065 my (undef, %arg) = @_;
1052 1066
1067 unless ($SIGPIPE_R) {
1068 if (AnyEvent::WIN32) {
1069 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1070 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1071 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1072 } else {
1073 pipe $SIGPIPE_R, $SIGPIPE_W;
1074 require Fcntl;
1075 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1076 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1077 }
1078
1079 $SIGPIPE_R
1080 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1081
1082 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1083 }
1084
1053 my $signal = uc $arg{signal} 1085 my $signal = uc $arg{signal}
1054 or Carp::croak "required option 'signal' is missing"; 1086 or Carp::croak "required option 'signal' is missing";
1055 1087
1056 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1088 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1057 $SIG{$signal} ||= sub { 1089 $SIG{$signal} ||= sub {
1058 $_->() for values %{ $SIG_CB{$signal} || {} }; 1090 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1091 undef $SIG_EV{$signal};
1059 }; 1092 };
1060 1093
1061 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1094 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
1062} 1095}
1063 1096
… …
1263used, and preference will be given to protocols mentioned earlier in the 1296used, and preference will be given to protocols mentioned earlier in the
1264list. 1297list.
1265 1298
1266This variable can effectively be used for denial-of-service attacks 1299This variable can effectively be used for denial-of-service attacks
1267against local programs (e.g. when setuid), although the impact is likely 1300against local programs (e.g. when setuid), although the impact is likely
1268small, as the program has to handle connection errors already- 1301small, as the program has to handle conenction and other failures anyways.
1269 1302
1270Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6, 1303Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1271but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4> 1304but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1272- only support IPv4, never try to resolve or contact IPv6 1305- only support IPv4, never try to resolve or contact IPv6
1273addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or 1306addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
… …
1533watcher. 1566watcher.
1534 1567
1535=head3 Results 1568=head3 Results
1536 1569
1537 name watchers bytes create invoke destroy comment 1570 name watchers bytes create invoke destroy comment
1538 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1571 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1539 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1572 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1540 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1573 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1541 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1574 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1542 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1575 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1543 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1576 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1544 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1577 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1545 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1578 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1546 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1579 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1547 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1580 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1548 1581
1549=head3 Discussion 1582=head3 Discussion
1550 1583
1551The benchmark does I<not> measure scalability of the event loop very 1584The benchmark does I<not> measure scalability of the event loop very
1552well. For example, a select-based event loop (such as the pure perl one) 1585well. For example, a select-based event loop (such as the pure perl one)
… …
1754watchers, as the management overhead dominates. 1787watchers, as the management overhead dominates.
1755 1788
1756=back 1789=back
1757 1790
1758 1791
1792=head1 SIGNALS
1793
1794AnyEvent currently installs handlers for these signals:
1795
1796=over 4
1797
1798=item SIGCHLD
1799
1800A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1801emulation for event loops that do not support them natively. Also, some
1802event loops install a similar handler.
1803
1804=item SIGPIPE
1805
1806A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1807when AnyEvent gets loaded.
1808
1809The rationale for this is that AnyEvent users usually do not really depend
1810on SIGPIPE delivery (which is purely an optimisation for shell use, or
1811badly-written programs), but C<SIGPIPE> can cause spurious and rare
1812program exits as a lot of people do not expect C<SIGPIPE> when writing to
1813some random socket.
1814
1815The rationale for installing a no-op handler as opposed to ignoring it is
1816that this way, the handler will be restored to defaults on exec.
1817
1818Feel free to install your own handler, or reset it to defaults.
1819
1820=back
1821
1822=cut
1823
1824$SIG{PIPE} = sub { }
1825 unless defined $SIG{PIPE};
1826
1827
1759=head1 FORK 1828=head1 FORK
1760 1829
1761Most event libraries are not fork-safe. The ones who are usually are 1830Most event libraries are not fork-safe. The ones who are usually are
1762because they rely on inefficient but fork-safe C<select> or C<poll> 1831because they rely on inefficient but fork-safe C<select> or C<poll>
1763calls. Only L<EV> is fully fork-aware. 1832calls. Only L<EV> is fully fork-aware.

Diff Legend

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