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Revision 1.198 by root, Thu Mar 26 20:17:44 2009 UTC vs.
Revision 1.221 by root, Fri Jun 26 06:33:17 2009 UTC

1=head1 NAME 1=head1 NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
6event loops.
6 7
7=head1 SYNOPSIS 8=head1 SYNOPSIS
8 9
9 use AnyEvent; 10 use AnyEvent;
10 11
12 # file descriptor readable
11 my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... }); 13 my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12 14
15 # one-shot or repeating timers
13 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... }); 16 my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ... 17 my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15 18
16 print AnyEvent->now; # prints current event loop time 19 print AnyEvent->now; # prints current event loop time
17 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time. 20 print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18 21
22 # POSIX signal
19 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... }); 23 my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20 24
25 # child process exit
21 my $w = AnyEvent->child (pid => $pid, cb => sub { 26 my $w = AnyEvent->child (pid => $pid, cb => sub {
22 my ($pid, $status) = @_; 27 my ($pid, $status) = @_;
23 ... 28 ...
24 }); 29 });
30
31 # called when event loop idle (if applicable)
32 my $w = AnyEvent->idle (cb => sub { ... });
25 33
26 my $w = AnyEvent->condvar; # stores whether a condition was flagged 34 my $w = AnyEvent->condvar; # stores whether a condition was flagged
27 $w->send; # wake up current and all future recv's 35 $w->send; # wake up current and all future recv's
28 $w->recv; # enters "main loop" till $condvar gets ->send 36 $w->recv; # enters "main loop" till $condvar gets ->send
29 # use a condvar in callback mode: 37 # use a condvar in callback mode:
168=head2 I/O WATCHERS 176=head2 I/O WATCHERS
169 177
170You can create an I/O watcher by calling the C<< AnyEvent->io >> method 178You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
172 180
173C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events 181C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
174(AnyEvent might or might not keep a reference to this file handle). C<poll> 182for events (AnyEvent might or might not keep a reference to this file
183handle). Note that only file handles pointing to things for which
184non-blocking operation makes sense are allowed. This includes sockets,
185most character devices, pipes, fifos and so on, but not for example files
186or block devices.
187
175must be a string that is either C<r> or C<w>, which creates a watcher 188C<poll> must be a string that is either C<r> or C<w>, which creates a
176waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the 189watcher waiting for "r"eadable or "w"ritable events, respectively.
190
177callback to invoke each time the file handle becomes ready. 191C<cb> is the callback to invoke each time the file handle becomes ready.
178 192
179Although the callback might get passed parameters, their value and 193Although the callback might get passed parameters, their value and
180presence is undefined and you cannot rely on them. Portable AnyEvent 194presence is undefined and you cannot rely on them. Portable AnyEvent
181callbacks cannot use arguments passed to I/O watcher callbacks. 195callbacks cannot use arguments passed to I/O watcher callbacks.
182 196
314In either case, if you care (and in most cases, you don't), then you 328In either case, if you care (and in most cases, you don't), then you
315can get whatever behaviour you want with any event loop, by taking the 329can get whatever behaviour you want with any event loop, by taking the
316difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 330difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
317account. 331account.
318 332
333=item AnyEvent->now_update
334
335Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
336the current time for each loop iteration (see the discussion of L<<
337AnyEvent->now >>, above).
338
339When a callback runs for a long time (or when the process sleeps), then
340this "current" time will differ substantially from the real time, which
341might affect timers and time-outs.
342
343When this is the case, you can call this method, which will update the
344event loop's idea of "current time".
345
346Note that updating the time I<might> cause some events to be handled.
347
319=back 348=back
320 349
321=head2 SIGNAL WATCHERS 350=head2 SIGNAL WATCHERS
322 351
323You can watch for signals using a signal watcher, C<signal> is the signal 352You can watch for signals using a signal watcher, C<signal> is the signal
363 392
364There is a slight catch to child watchers, however: you usually start them 393There is a slight catch to child watchers, however: you usually start them
365I<after> the child process was created, and this means the process could 394I<after> the child process was created, and this means the process could
366have exited already (and no SIGCHLD will be sent anymore). 395have exited already (and no SIGCHLD will be sent anymore).
367 396
368Not all event models handle this correctly (POE doesn't), but even for 397Not all event models handle this correctly (neither POE nor IO::Async do,
398see their AnyEvent::Impl manpages for details), but even for event models
369event models that I<do> handle this correctly, they usually need to be 399that I<do> handle this correctly, they usually need to be loaded before
370loaded before the process exits (i.e. before you fork in the first place). 400the process exits (i.e. before you fork in the first place). AnyEvent's
401pure perl event loop handles all cases correctly regardless of when you
402start the watcher.
371 403
372This means you cannot create a child watcher as the very first thing in an 404This means you cannot create a child watcher as the very first
373AnyEvent program, you I<have> to create at least one watcher before you 405thing in an AnyEvent program, you I<have> to create at least one
374C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 406watcher before you C<fork> the child (alternatively, you can call
407C<AnyEvent::detect>).
375 408
376Example: fork a process and wait for it 409Example: fork a process and wait for it
377 410
378 my $done = AnyEvent->condvar; 411 my $done = AnyEvent->condvar;
379 412
389 ); 422 );
390 423
391 # do something else, then wait for process exit 424 # do something else, then wait for process exit
392 $done->recv; 425 $done->recv;
393 426
427=head2 IDLE WATCHERS
428
429Sometimes there is a need to do something, but it is not so important
430to do it instantly, but only when there is nothing better to do. This
431"nothing better to do" is usually defined to be "no other events need
432attention by the event loop".
433
434Idle watchers ideally get invoked when the event loop has nothing
435better to do, just before it would block the process to wait for new
436events. Instead of blocking, the idle watcher is invoked.
437
438Most event loops unfortunately do not really support idle watchers (only
439EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440will simply call the callback "from time to time".
441
442Example: read lines from STDIN, but only process them when the
443program is otherwise idle:
444
445 my @lines; # read data
446 my $idle_w;
447 my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
448 push @lines, scalar <STDIN>;
449
450 # start an idle watcher, if not already done
451 $idle_w ||= AnyEvent->idle (cb => sub {
452 # handle only one line, when there are lines left
453 if (my $line = shift @lines) {
454 print "handled when idle: $line";
455 } else {
456 # otherwise disable the idle watcher again
457 undef $idle_w;
458 }
459 });
460 });
461
394=head2 CONDITION VARIABLES 462=head2 CONDITION VARIABLES
395 463
396If you are familiar with some event loops you will know that all of them 464If you are familiar with some event loops you will know that all of them
397require you to run some blocking "loop", "run" or similar function that 465require you to run some blocking "loop", "run" or similar function that
398will actively watch for new events and call your callbacks. 466will actively watch for new events and call your callbacks.
666 AnyEvent::Impl::Tk based on Tk, very bad choice. 734 AnyEvent::Impl::Tk based on Tk, very bad choice.
667 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). 735 AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
668 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 736 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
669 AnyEvent::Impl::POE based on POE, not generic enough for full support. 737 AnyEvent::Impl::POE based on POE, not generic enough for full support.
670 738
739 # warning, support for IO::Async is only partial, as it is too broken
740 # and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
741 AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
742
671There is no support for WxWidgets, as WxWidgets has no support for 743There is no support for WxWidgets, as WxWidgets has no support for
672watching file handles. However, you can use WxWidgets through the 744watching file handles. However, you can use WxWidgets through the
673POE Adaptor, as POE has a Wx backend that simply polls 20 times per 745POE Adaptor, as POE has a Wx backend that simply polls 20 times per
674second, which was considered to be too horrible to even consider for 746second, which was considered to be too horrible to even consider for
675AnyEvent. Likewise, other POE backends can be used by AnyEvent by using 747AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
867no warnings; 939no warnings;
868use strict qw(vars subs); 940use strict qw(vars subs);
869 941
870use Carp; 942use Carp;
871 943
872our $VERSION = 4.341; 944our $VERSION = 4.42;
873our $MODEL; 945our $MODEL;
874 946
875our $AUTOLOAD; 947our $AUTOLOAD;
876our @ISA; 948our @ISA;
877 949
878our @REGISTRY; 950our @REGISTRY;
879 951
880our $WIN32; 952our $WIN32;
881 953
882BEGIN { 954BEGIN {
883 my $win32 = ! ! ($^O =~ /mswin32/i); 955 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
884 eval "sub WIN32(){ $win32 }"; 956 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
957
958 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
959 if ${^TAINT};
885} 960}
886 961
887our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 962our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
888 963
889our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 964our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
907 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 982 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
908 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 983 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
909 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 984 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
910 [Wx:: => AnyEvent::Impl::POE::], 985 [Wx:: => AnyEvent::Impl::POE::],
911 [Prima:: => AnyEvent::Impl::POE::], 986 [Prima:: => AnyEvent::Impl::POE::],
987 # IO::Async is just too broken - we would need workaorunds for its
988 # byzantine signal and broken child handling, among others.
989 # IO::Async is rather hard to detect, as it doesn't have any
990 # obvious default class.
991# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
992# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
993# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
912); 994);
913 995
914our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 996our %method = map +($_ => 1),
997 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
915 998
916our @post_detect; 999our @post_detect;
917 1000
918sub post_detect(&) { 1001sub post_detect(&) {
919 my ($cb) = @_; 1002 my ($cb) = @_;
924 1 1007 1
925 } else { 1008 } else {
926 push @post_detect, $cb; 1009 push @post_detect, $cb;
927 1010
928 defined wantarray 1011 defined wantarray
929 ? bless \$cb, "AnyEvent::Util::PostDetect" 1012 ? bless \$cb, "AnyEvent::Util::postdetect"
930 : () 1013 : ()
931 } 1014 }
932} 1015}
933 1016
934sub AnyEvent::Util::PostDetect::DESTROY { 1017sub AnyEvent::Util::postdetect::DESTROY {
935 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1018 @post_detect = grep $_ != ${$_[0]}, @post_detect;
936} 1019}
937 1020
938sub detect() { 1021sub detect() {
939 unless ($MODEL) { 1022 unless ($MODEL) {
976 last; 1059 last;
977 } 1060 }
978 } 1061 }
979 1062
980 $MODEL 1063 $MODEL
981 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1064 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
982 } 1065 }
983 } 1066 }
984 1067
985 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1068 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
986 1069
1007} 1090}
1008 1091
1009# utility function to dup a filehandle. this is used by many backends 1092# utility function to dup a filehandle. this is used by many backends
1010# to support binding more than one watcher per filehandle (they usually 1093# to support binding more than one watcher per filehandle (they usually
1011# allow only one watcher per fd, so we dup it to get a different one). 1094# allow only one watcher per fd, so we dup it to get a different one).
1012sub _dupfh($$$$) { 1095sub _dupfh($$;$$) {
1013 my ($poll, $fh, $r, $w) = @_; 1096 my ($poll, $fh, $r, $w) = @_;
1014 1097
1015 # cygwin requires the fh mode to be matching, unix doesn't 1098 # cygwin requires the fh mode to be matching, unix doesn't
1016 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1099 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1017 : $poll eq "w" ? ($w, ">") 1100 : $poll eq "w" ? ($w, ">")
1018 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'"; 1101 : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1019 1102
1020 open my $fh2, "$mode&" . fileno $fh 1103 open my $fh2, "$mode&" . fileno $fh
1021 or die "cannot dup() filehandle: $!"; 1104 or die "cannot dup() filehandle: $!,";
1022 1105
1023 # we assume CLOEXEC is already set by perl in all important cases 1106 # we assume CLOEXEC is already set by perl in all important cases
1024 1107
1025 ($fh2, $rw) 1108 ($fh2, $rw)
1026} 1109}
1027 1110
1028package AnyEvent::Base; 1111package AnyEvent::Base;
1029 1112
1030# default implementation for now and time 1113# default implementations for many methods
1031 1114
1032BEGIN { 1115BEGIN {
1033 if (eval "use Time::HiRes (); time (); 1") { 1116 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1034 *_time = \&Time::HiRes::time; 1117 *_time = \&Time::HiRes::time;
1035 # if (eval "use POSIX (); (POSIX::times())... 1118 # if (eval "use POSIX (); (POSIX::times())...
1036 } else { 1119 } else {
1037 *_time = sub { time }; # epic fail 1120 *_time = sub { time }; # epic fail
1038 } 1121 }
1039} 1122}
1040 1123
1041sub time { _time } 1124sub time { _time }
1042sub now { _time } 1125sub now { _time }
1126sub now_update { }
1043 1127
1044# default implementation for ->condvar 1128# default implementation for ->condvar
1045 1129
1046sub condvar { 1130sub condvar {
1047 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1131 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1048} 1132}
1049 1133
1050# default implementation for ->signal 1134# default implementation for ->signal
1051 1135
1052our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); 1136our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1064 1148
1065sub signal { 1149sub signal {
1066 my (undef, %arg) = @_; 1150 my (undef, %arg) = @_;
1067 1151
1068 unless ($SIGPIPE_R) { 1152 unless ($SIGPIPE_R) {
1153 require Fcntl;
1154
1069 if (AnyEvent::WIN32) { 1155 if (AnyEvent::WIN32) {
1156 require AnyEvent::Util;
1157
1070 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); 1158 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1071 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R; 1159 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1072 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case 1160 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1073 } else { 1161 } else {
1074 pipe $SIGPIPE_R, $SIGPIPE_W; 1162 pipe $SIGPIPE_R, $SIGPIPE_W;
1075 require Fcntl;
1076 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; 1163 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1077 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case 1164 fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1165
1166 # not strictly required, as $^F is normally 2, but let's make sure...
1167 fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1168 fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1078 } 1169 }
1079 1170
1080 $SIGPIPE_R 1171 $SIGPIPE_R
1081 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; 1172 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1082 1173
1086 my $signal = uc $arg{signal} 1177 my $signal = uc $arg{signal}
1087 or Carp::croak "required option 'signal' is missing"; 1178 or Carp::croak "required option 'signal' is missing";
1088 1179
1089 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1180 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1090 $SIG{$signal} ||= sub { 1181 $SIG{$signal} ||= sub {
1182 local $!;
1091 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; 1183 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1092 undef $SIG_EV{$signal}; 1184 undef $SIG_EV{$signal};
1093 }; 1185 };
1094 1186
1095 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1187 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1096} 1188}
1097 1189
1098sub AnyEvent::Base::Signal::DESTROY { 1190sub AnyEvent::Base::signal::DESTROY {
1099 my ($signal, $cb) = @{$_[0]}; 1191 my ($signal, $cb) = @{$_[0]};
1100 1192
1101 delete $SIG_CB{$signal}{$cb}; 1193 delete $SIG_CB{$signal}{$cb};
1102 1194
1195 # delete doesn't work with older perls - they then
1196 # print weird messages, or just unconditionally exit
1197 # instead of getting the default action.
1103 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1198 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1104} 1199}
1105 1200
1106# default implementation for ->child 1201# default implementation for ->child
1107 1202
1108our %PID_CB; 1203our %PID_CB;
1109our $CHLD_W; 1204our $CHLD_W;
1110our $CHLD_DELAY_W; 1205our $CHLD_DELAY_W;
1111our $PID_IDLE;
1112our $WNOHANG; 1206our $WNOHANG;
1113 1207
1114sub _child_wait { 1208sub _sigchld {
1115 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1209 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1116 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1210 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1117 (values %{ $PID_CB{0} || {} }); 1211 (values %{ $PID_CB{0} || {} });
1118 } 1212 }
1119
1120 undef $PID_IDLE;
1121}
1122
1123sub _sigchld {
1124 # make sure we deliver these changes "synchronous" with the event loop.
1125 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1126 undef $CHLD_DELAY_W;
1127 &_child_wait;
1128 });
1129} 1213}
1130 1214
1131sub child { 1215sub child {
1132 my (undef, %arg) = @_; 1216 my (undef, %arg) = @_;
1133 1217
1134 defined (my $pid = $arg{pid} + 0) 1218 defined (my $pid = $arg{pid} + 0)
1135 or Carp::croak "required option 'pid' is missing"; 1219 or Carp::croak "required option 'pid' is missing";
1136 1220
1137 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1221 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1138 1222
1139 unless ($WNOHANG) {
1140 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1223 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1141 }
1142 1224
1143 unless ($CHLD_W) { 1225 unless ($CHLD_W) {
1144 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1226 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1145 # child could be a zombie already, so make at least one round 1227 # child could be a zombie already, so make at least one round
1146 &_sigchld; 1228 &_sigchld;
1147 } 1229 }
1148 1230
1149 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 1231 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1150} 1232}
1151 1233
1152sub AnyEvent::Base::Child::DESTROY { 1234sub AnyEvent::Base::child::DESTROY {
1153 my ($pid, $cb) = @{$_[0]}; 1235 my ($pid, $cb) = @{$_[0]};
1154 1236
1155 delete $PID_CB{$pid}{$cb}; 1237 delete $PID_CB{$pid}{$cb};
1156 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1238 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1157 1239
1158 undef $CHLD_W unless keys %PID_CB; 1240 undef $CHLD_W unless keys %PID_CB;
1241}
1242
1243# idle emulation is done by simply using a timer, regardless
1244# of whether the process is idle or not, and not letting
1245# the callback use more than 50% of the time.
1246sub idle {
1247 my (undef, %arg) = @_;
1248
1249 my ($cb, $w, $rcb) = $arg{cb};
1250
1251 $rcb = sub {
1252 if ($cb) {
1253 $w = _time;
1254 &$cb;
1255 $w = _time - $w;
1256
1257 # never use more then 50% of the time for the idle watcher,
1258 # within some limits
1259 $w = 0.0001 if $w < 0.0001;
1260 $w = 5 if $w > 5;
1261
1262 $w = AnyEvent->timer (after => $w, cb => $rcb);
1263 } else {
1264 # clean up...
1265 undef $w;
1266 undef $rcb;
1267 }
1268 };
1269
1270 $w = AnyEvent->timer (after => 0.05, cb => $rcb);
1271
1272 bless \\$cb, "AnyEvent::Base::idle"
1273}
1274
1275sub AnyEvent::Base::idle::DESTROY {
1276 undef $${$_[0]};
1159} 1277}
1160 1278
1161package AnyEvent::CondVar; 1279package AnyEvent::CondVar;
1162 1280
1163our @ISA = AnyEvent::CondVar::Base::; 1281our @ISA = AnyEvent::CondVar::Base::;
1237so on. 1355so on.
1238 1356
1239=head1 ENVIRONMENT VARIABLES 1357=head1 ENVIRONMENT VARIABLES
1240 1358
1241The following environment variables are used by this module or its 1359The following environment variables are used by this module or its
1242submodules: 1360submodules.
1361
1362Note that AnyEvent will remove I<all> environment variables starting with
1363C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
1364enabled.
1243 1365
1244=over 4 1366=over 4
1245 1367
1246=item C<PERL_ANYEVENT_VERBOSE> 1368=item C<PERL_ANYEVENT_VERBOSE>
1247 1369
1259=item C<PERL_ANYEVENT_STRICT> 1381=item C<PERL_ANYEVENT_STRICT>
1260 1382
1261AnyEvent does not do much argument checking by default, as thorough 1383AnyEvent does not do much argument checking by default, as thorough
1262argument checking is very costly. Setting this variable to a true value 1384argument checking is very costly. Setting this variable to a true value
1263will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly 1385will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1264check the arguments passed to most method calls. If it finds any problems 1386check the arguments passed to most method calls. If it finds any problems,
1265it will croak. 1387it will croak.
1266 1388
1267In other words, enables "strict" mode. 1389In other words, enables "strict" mode.
1268 1390
1269Unlike C<use strict>, it is definitely recommended ot keep it off in 1391Unlike C<use strict>, it is definitely recommended to keep it off in
1270production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while 1392production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1271developing programs can be very useful, however. 1393developing programs can be very useful, however.
1272 1394
1273=item C<PERL_ANYEVENT_MODEL> 1395=item C<PERL_ANYEVENT_MODEL>
1274 1396
1573 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers 1695 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1574 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal 1696 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1575 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation 1697 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1576 Event/Event 16000 517 32.20 31.80 0.81 Event native interface 1698 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1577 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers 1699 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1700 IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
1701 IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1578 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour 1702 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1579 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers 1703 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1580 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event 1704 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1581 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select 1705 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1582 1706
1611performance becomes really bad with lots of file descriptors (and few of 1735performance becomes really bad with lots of file descriptors (and few of
1612them active), of course, but this was not subject of this benchmark. 1736them active), of course, but this was not subject of this benchmark.
1613 1737
1614The C<Event> module has a relatively high setup and callback invocation 1738The C<Event> module has a relatively high setup and callback invocation
1615cost, but overall scores in on the third place. 1739cost, but overall scores in on the third place.
1740
1741C<IO::Async> performs admirably well, about on par with C<Event>, even
1742when using its pure perl backend.
1616 1743
1617C<Glib>'s memory usage is quite a bit higher, but it features a 1744C<Glib>'s memory usage is quite a bit higher, but it features a
1618faster callback invocation and overall ends up in the same class as 1745faster callback invocation and overall ends up in the same class as
1619C<Event>. However, Glib scales extremely badly, doubling the number of 1746C<Event>. However, Glib scales extremely badly, doubling the number of
1620watchers increases the processing time by more than a factor of four, 1747watchers increases the processing time by more than a factor of four,
1698it to another server. This includes deleting the old timeout and creating 1825it to another server. This includes deleting the old timeout and creating
1699a new one that moves the timeout into the future. 1826a new one that moves the timeout into the future.
1700 1827
1701=head3 Results 1828=head3 Results
1702 1829
1703 name sockets create request 1830 name sockets create request
1704 EV 20000 69.01 11.16 1831 EV 20000 69.01 11.16
1705 Perl 20000 73.32 35.87 1832 Perl 20000 73.32 35.87
1833 IOAsync 20000 157.00 98.14 epoll
1834 IOAsync 20000 159.31 616.06 poll
1706 Event 20000 212.62 257.32 1835 Event 20000 212.62 257.32
1707 Glib 20000 651.16 1896.30 1836 Glib 20000 651.16 1896.30
1708 POE 20000 349.67 12317.24 uses POE::Loop::Event 1837 POE 20000 349.67 12317.24 uses POE::Loop::Event
1709 1838
1710=head3 Discussion 1839=head3 Discussion
1711 1840
1712This benchmark I<does> measure scalability and overall performance of the 1841This benchmark I<does> measure scalability and overall performance of the
1713particular event loop. 1842particular event loop.
1715EV is again fastest. Since it is using epoll on my system, the setup time 1844EV is again fastest. Since it is using epoll on my system, the setup time
1716is relatively high, though. 1845is relatively high, though.
1717 1846
1718Perl surprisingly comes second. It is much faster than the C-based event 1847Perl surprisingly comes second. It is much faster than the C-based event
1719loops Event and Glib. 1848loops Event and Glib.
1849
1850IO::Async performs very well when using its epoll backend, and still quite
1851good compared to Glib when using its pure perl backend.
1720 1852
1721Event suffers from high setup time as well (look at its code and you will 1853Event suffers from high setup time as well (look at its code and you will
1722understand why). Callback invocation also has a high overhead compared to 1854understand why). Callback invocation also has a high overhead compared to
1723the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event 1855the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1724uses select or poll in basically all documented configurations. 1856uses select or poll in basically all documented configurations.
1787=item * C-based event loops perform very well with small number of 1919=item * C-based event loops perform very well with small number of
1788watchers, as the management overhead dominates. 1920watchers, as the management overhead dominates.
1789 1921
1790=back 1922=back
1791 1923
1924=head2 THE IO::Lambda BENCHMARK
1925
1926Recently I was told about the benchmark in the IO::Lambda manpage, which
1927could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1928simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1929shouldn't come as a surprise to anybody). As such, the benchmark is
1930fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1931very optimal. But how would AnyEvent compare when used without the extra
1932baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1933
1934The benchmark itself creates an echo-server, and then, for 500 times,
1935connects to the echo server, sends a line, waits for the reply, and then
1936creates the next connection. This is a rather bad benchmark, as it doesn't
1937test the efficiency of the framework or much non-blocking I/O, but it is a
1938benchmark nevertheless.
1939
1940 name runtime
1941 Lambda/select 0.330 sec
1942 + optimized 0.122 sec
1943 Lambda/AnyEvent 0.327 sec
1944 + optimized 0.138 sec
1945 Raw sockets/select 0.077 sec
1946 POE/select, components 0.662 sec
1947 POE/select, raw sockets 0.226 sec
1948 POE/select, optimized 0.404 sec
1949
1950 AnyEvent/select/nb 0.085 sec
1951 AnyEvent/EV/nb 0.068 sec
1952 +state machine 0.134 sec
1953
1954The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1955benchmarks actually make blocking connects and use 100% blocking I/O,
1956defeating the purpose of an event-based solution. All of the newly
1957written AnyEvent benchmarks use 100% non-blocking connects (using
1958AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1959resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1960generally require a lot more bookkeeping and event handling than blocking
1961connects (which involve a single syscall only).
1962
1963The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1964offers similar expressive power as POE and IO::Lambda, using conventional
1965Perl syntax. This means that both the echo server and the client are 100%
1966non-blocking, further placing it at a disadvantage.
1967
1968As you can see, the AnyEvent + EV combination even beats the
1969hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1970backend easily beats IO::Lambda and POE.
1971
1972And even the 100% non-blocking version written using the high-level (and
1973slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
1974large margin, even though it does all of DNS, tcp-connect and socket I/O
1975in a non-blocking way.
1976
1977The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1978F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1979part of the IO::lambda distribution and were used without any changes.
1980
1792 1981
1793=head1 SIGNALS 1982=head1 SIGNALS
1794 1983
1795AnyEvent currently installs handlers for these signals: 1984AnyEvent currently installs handlers for these signals:
1796 1985
1799=item SIGCHLD 1988=item SIGCHLD
1800 1989
1801A handler for C<SIGCHLD> is installed by AnyEvent's child watcher 1990A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1802emulation for event loops that do not support them natively. Also, some 1991emulation for event loops that do not support them natively. Also, some
1803event loops install a similar handler. 1992event loops install a similar handler.
1993
1994If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
1995reset it to default, to avoid losing child exit statuses.
1804 1996
1805=item SIGPIPE 1997=item SIGPIPE
1806 1998
1807A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef> 1999A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1808when AnyEvent gets loaded. 2000when AnyEvent gets loaded.
1820 2012
1821=back 2013=back
1822 2014
1823=cut 2015=cut
1824 2016
2017undef $SIG{CHLD}
2018 if $SIG{CHLD} eq 'IGNORE';
2019
1825$SIG{PIPE} = sub { } 2020$SIG{PIPE} = sub { }
1826 unless defined $SIG{PIPE}; 2021 unless defined $SIG{PIPE};
1827
1828 2022
1829=head1 FORK 2023=head1 FORK
1830 2024
1831Most event libraries are not fork-safe. The ones who are usually are 2025Most event libraries are not fork-safe. The ones who are usually are
1832because they rely on inefficient but fork-safe C<select> or C<poll> 2026because they rely on inefficient but fork-safe C<select> or C<poll>
1853 use AnyEvent; 2047 use AnyEvent;
1854 2048
1855Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2049Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1856be used to probe what backend is used and gain other information (which is 2050be used to probe what backend is used and gain other information (which is
1857probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2051probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1858$ENV{PERL_ANYEGENT_STRICT}. 2052$ENV{PERL_ANYEVENT_STRICT}.
2053
2054Note that AnyEvent will remove I<all> environment variables starting with
2055C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2056enabled.
1859 2057
1860 2058
1861=head1 BUGS 2059=head1 BUGS
1862 2060
1863Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2061Perl 5.8 has numerous memleaks that sometimes hit this module and are hard

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