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 1.179 by root, Thu Sep 4 10:58:58 2008 UTC vs.
Revision 1.219 by root, Thu Jun 25 11:16:08 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 $condvar gets ->send
29 # use a condvar in callback mode: 37 # use a condvar in callback mode:
137These watchers are normal Perl objects with normal Perl lifetime. After 145These watchers are normal Perl objects with normal Perl lifetime. After
138creating a watcher it will immediately "watch" for events and invoke the 146creating a watcher it will immediately "watch" for events and invoke the
139callback when the event occurs (of course, only when the event model 147callback when the event occurs (of course, only when the event model
140is in control). 148is in control).
141 149
150Note that B<callbacks must not permanently change global variables>
151potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152callbacks must not C<die> >>. The former is good programming practise in
153Perl and the latter stems from the fact that exception handling differs
154widely between event loops.
155
142To disable the watcher you have to destroy it (e.g. by setting the 156To 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 157variable you store it in to C<undef> or otherwise deleting all references
144to it). 158to it).
145 159
146All watchers are created by calling a method on the C<AnyEvent> class. 160All watchers are created by calling a method on the C<AnyEvent> class.
162=head2 I/O WATCHERS 176=head2 I/O WATCHERS
163 177
164You 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
165with the following mandatory key-value pairs as arguments: 179with the following mandatory key-value pairs as arguments:
166 180
167C<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
168(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
169must 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
170waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the 189watcher waiting for "r"eadable or "w"ritable events, respectively.
190
171callback to invoke each time the file handle becomes ready. 191C<cb> is the callback to invoke each time the file handle becomes ready.
172 192
173Although the callback might get passed parameters, their value and 193Although the callback might get passed parameters, their value and
174presence is undefined and you cannot rely on them. Portable AnyEvent 194presence is undefined and you cannot rely on them. Portable AnyEvent
175callbacks cannot use arguments passed to I/O watcher callbacks. 195callbacks cannot use arguments passed to I/O watcher callbacks.
176 196
308In 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
309can 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
310difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into 330difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311account. 331account.
312 332
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
313=back 348=back
314 349
315=head2 SIGNAL WATCHERS 350=head2 SIGNAL WATCHERS
316 351
317You 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
340=head2 CHILD PROCESS WATCHERS 375=head2 CHILD PROCESS WATCHERS
341 376
342You can also watch on a child process exit and catch its exit status. 377You can also watch on a child process exit and catch its exit status.
343 378
344The child process is specified by the C<pid> argument (if set to C<0>, it 379The child process is specified by the C<pid> argument (if set to C<0>, it
345watches for any child process exit). The watcher will trigger as often 380watches for any child process exit). The watcher will triggered only when
346as status change for the child are received. This works by installing a 381the child process has finished and an exit status is available, not on
347signal handler for C<SIGCHLD>. The callback will be called with the pid 382any trace events (stopped/continued).
348and exit status (as returned by waitpid), so unlike other watcher types, 383
349you I<can> rely on child watcher callback arguments. 384The callback will be called with the pid and exit status (as returned by
385waitpid), so unlike other watcher types, you I<can> rely on child watcher
386callback arguments.
387
388This watcher type works by installing a signal handler for C<SIGCHLD>,
389and since it cannot be shared, nothing else should use SIGCHLD or reap
390random child processes (waiting for specific child processes, e.g. inside
391C<system>, is just fine).
350 392
351There 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
352I<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
353have exited already (and no SIGCHLD will be sent anymore). 395have exited already (and no SIGCHLD will be sent anymore).
354 396
355Not 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
356event 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
357loaded 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.
358 403
359This 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
360AnyEvent 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
361C<fork> the child (alternatively, you can call C<AnyEvent::detect>). 406watcher before you C<fork> the child (alternatively, you can call
407C<AnyEvent::detect>).
362 408
363Example: fork a process and wait for it 409Example: fork a process and wait for it
364 410
365 my $done = AnyEvent->condvar; 411 my $done = AnyEvent->condvar;
366 412
376 ); 422 );
377 423
378 # do something else, then wait for process exit 424 # do something else, then wait for process exit
379 $done->recv; 425 $done->recv;
380 426
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
381=head2 CONDITION VARIABLES 462=head2 CONDITION VARIABLES
382 463
383If 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
384require you to run some blocking "loop", "run" or similar function that 465require you to run some blocking "loop", "run" or similar function that
385will actively watch for new events and call your callbacks. 466will actively watch for new events and call your callbacks.
653 AnyEvent::Impl::Tk based on Tk, very bad choice. 734 AnyEvent::Impl::Tk based on Tk, very bad choice.
654 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).
655 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. 736 AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656 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.
657 738
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
658There is no support for WxWidgets, as WxWidgets has no support for 743There is no support for WxWidgets, as WxWidgets has no support for
659watching file handles. However, you can use WxWidgets through the 744watching file handles. However, you can use WxWidgets through the
660POE 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
661second, which was considered to be too horrible to even consider for 746second, which was considered to be too horrible to even consider for
662AnyEvent. Likewise, other POE backends can be used by AnyEvent by using 747AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
818=item L<AnyEvent::IGS> 903=item L<AnyEvent::IGS>
819 904
820A non-blocking interface to the Internet Go Server protocol (used by 905A non-blocking interface to the Internet Go Server protocol (used by
821L<App::IGS>). 906L<App::IGS>).
822 907
823=item L<Net::IRC3> 908=item L<AnyEvent::IRC>
824 909
825AnyEvent based IRC client module family. 910AnyEvent based IRC client module family (replacing the older Net::IRC3).
826 911
827=item L<Net::XMPP2> 912=item L<Net::XMPP2>
828 913
829AnyEvent based XMPP (Jabber protocol) module family. 914AnyEvent based XMPP (Jabber protocol) module family.
830 915
850=cut 935=cut
851 936
852package AnyEvent; 937package AnyEvent;
853 938
854no warnings; 939no warnings;
855use strict; 940use strict qw(vars subs);
856 941
857use Carp; 942use Carp;
858 943
859our $VERSION = 4.233; 944our $VERSION = 4.412;
860our $MODEL; 945our $MODEL;
861 946
862our $AUTOLOAD; 947our $AUTOLOAD;
863our @ISA; 948our @ISA;
864 949
865our @REGISTRY; 950our @REGISTRY;
866 951
867our $WIN32; 952our $WIN32;
868 953
869BEGIN { 954BEGIN {
870 my $win32 = ! ! ($^O =~ /mswin32/i); 955 eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871 eval "sub WIN32(){ $win32 }"; 956 eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
957
958 delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
959 if ${^TAINT};
872} 960}
873 961
874our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 962our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
875 963
876our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred 964our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
894 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy 982 [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
895 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program 983 [Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza 984 [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897 [Wx:: => AnyEvent::Impl::POE::], 985 [Wx:: => AnyEvent::Impl::POE::],
898 [Prima:: => AnyEvent::Impl::POE::], 986 [Prima:: => AnyEvent::Impl::POE::],
987 # IO::Async is just too broken - we would need workaorunds for its
988 # byzantine signal and broken child handling, among others.
989 # IO::Async is rather hard to detect, as it doesn't have any
990 # obvious default class.
991# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
992# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
993# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
899); 994);
900 995
901our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY); 996our %method = map +($_ => 1),
997 qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902 998
903our @post_detect; 999our @post_detect;
904 1000
905sub post_detect(&) { 1001sub post_detect(&) {
906 my ($cb) = @_; 1002 my ($cb) = @_;
911 1 1007 1
912 } else { 1008 } else {
913 push @post_detect, $cb; 1009 push @post_detect, $cb;
914 1010
915 defined wantarray 1011 defined wantarray
916 ? bless \$cb, "AnyEvent::Util::PostDetect" 1012 ? bless \$cb, "AnyEvent::Util::postdetect"
917 : () 1013 : ()
918 } 1014 }
919} 1015}
920 1016
921sub AnyEvent::Util::PostDetect::DESTROY { 1017sub AnyEvent::Util::postdetect::DESTROY {
922 @post_detect = grep $_ != ${$_[0]}, @post_detect; 1018 @post_detect = grep $_ != ${$_[0]}, @post_detect;
923} 1019}
924 1020
925sub detect() { 1021sub detect() {
926 unless ($MODEL) { 1022 unless ($MODEL) {
963 last; 1059 last;
964 } 1060 }
965 } 1061 }
966 1062
967 $MODEL 1063 $MODEL
968 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib."; 1064 or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969 } 1065 }
970 } 1066 }
971 1067
972 push @{"$MODEL\::ISA"}, "AnyEvent::Base"; 1068 push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973 1069
994} 1090}
995 1091
996# 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
997# to support binding more than one watcher per filehandle (they usually 1093# to support binding more than one watcher per filehandle (they usually
998# 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).
999sub _dupfh($$$$) { 1095sub _dupfh($$;$$) {
1000 my ($poll, $fh, $r, $w) = @_; 1096 my ($poll, $fh, $r, $w) = @_;
1001
1002 require Fcntl;
1003 1097
1004 # cygwin requires the fh mode to be matching, unix doesn't 1098 # cygwin requires the fh mode to be matching, unix doesn't
1005 my ($rw, $mode) = $poll eq "r" ? ($r, "<") 1099 my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1006 : $poll eq "w" ? ($w, ">") 1100 : $poll eq "w" ? ($w, ">")
1007 : 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'";
1008 1102
1009 open my $fh2, "$mode&" . fileno $fh 1103 open my $fh2, "$mode&" . fileno $fh
1010 or die "cannot dup() filehandle: $!"; 1104 or die "cannot dup() filehandle: $!,";
1011 1105
1012 # 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
1013 1107
1014 ($fh2, $rw) 1108 ($fh2, $rw)
1015} 1109}
1016 1110
1017package AnyEvent::Base; 1111package AnyEvent::Base;
1018 1112
1019# default implementation for now and time 1113# default implementations for many methods
1020 1114
1021BEGIN { 1115BEGIN {
1022 if (eval "use Time::HiRes (); time (); 1") { 1116 if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1023 *_time = \&Time::HiRes::time; 1117 *_time = \&Time::HiRes::time;
1024 # if (eval "use POSIX (); (POSIX::times())... 1118 # if (eval "use POSIX (); (POSIX::times())...
1025 } else { 1119 } else {
1026 *_time = \&CORE::time; # epic fail 1120 *_time = sub { time }; # epic fail
1027 } 1121 }
1028} 1122}
1029 1123
1030sub time { _time } 1124sub time { _time }
1031sub now { _time } 1125sub now { _time }
1126sub now_update { }
1032 1127
1033# default implementation for ->condvar 1128# default implementation for ->condvar
1034 1129
1035sub condvar { 1130sub condvar {
1036 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: 1131 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1037} 1132}
1038 1133
1039# default implementation for ->signal 1134# default implementation for ->signal
1040 1135
1041our %SIG_CB; 1136our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1137
1138sub _signal_exec {
1139 sysread $SIGPIPE_R, my $dummy, 4;
1140
1141 while (%SIG_EV) {
1142 for (keys %SIG_EV) {
1143 delete $SIG_EV{$_};
1144 $_->() for values %{ $SIG_CB{$_} || {} };
1145 }
1146 }
1147}
1042 1148
1043sub signal { 1149sub signal {
1044 my (undef, %arg) = @_; 1150 my (undef, %arg) = @_;
1045 1151
1152 unless ($SIGPIPE_R) {
1153 require Fcntl;
1154
1155 if (AnyEvent::WIN32) {
1156 require AnyEvent::Util;
1157
1158 ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1159 AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1160 AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1161 } else {
1162 pipe $SIGPIPE_R, $SIGPIPE_W;
1163 fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
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;
1169 }
1170
1171 $SIGPIPE_R
1172 or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1173
1174 $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1175 }
1176
1046 my $signal = uc $arg{signal} 1177 my $signal = uc $arg{signal}
1047 or Carp::croak "required option 'signal' is missing"; 1178 or Carp::croak "required option 'signal' is missing";
1048 1179
1049 $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; 1180 $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1050 $SIG{$signal} ||= sub { 1181 $SIG{$signal} ||= sub {
1051 $_->() for values %{ $SIG_CB{$signal} || {} }; 1182 local $!;
1183 syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1184 undef $SIG_EV{$signal};
1052 }; 1185 };
1053 1186
1054 bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" 1187 bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1055} 1188}
1056 1189
1057sub AnyEvent::Base::Signal::DESTROY { 1190sub AnyEvent::Base::signal::DESTROY {
1058 my ($signal, $cb) = @{$_[0]}; 1191 my ($signal, $cb) = @{$_[0]};
1059 1192
1060 delete $SIG_CB{$signal}{$cb}; 1193 delete $SIG_CB{$signal}{$cb};
1061 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.
1062 delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; 1198 undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1063} 1199}
1064 1200
1065# default implementation for ->child 1201# default implementation for ->child
1066 1202
1067our %PID_CB; 1203our %PID_CB;
1068our $CHLD_W; 1204our $CHLD_W;
1069our $CHLD_DELAY_W; 1205our $CHLD_DELAY_W;
1070our $PID_IDLE;
1071our $WNOHANG; 1206our $WNOHANG;
1072 1207
1073sub _child_wait { 1208sub _sigchld {
1074 while (0 < (my $pid = waitpid -1, $WNOHANG)) { 1209 while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1075 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), 1210 $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
1076 (values %{ $PID_CB{0} || {} }); 1211 (values %{ $PID_CB{0} || {} });
1077 } 1212 }
1078
1079 undef $PID_IDLE;
1080}
1081
1082sub _sigchld {
1083 # make sure we deliver these changes "synchronous" with the event loop.
1084 $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1085 undef $CHLD_DELAY_W;
1086 &_child_wait;
1087 });
1088} 1213}
1089 1214
1090sub child { 1215sub child {
1091 my (undef, %arg) = @_; 1216 my (undef, %arg) = @_;
1092 1217
1093 defined (my $pid = $arg{pid} + 0) 1218 defined (my $pid = $arg{pid} + 0)
1094 or Carp::croak "required option 'pid' is missing"; 1219 or Carp::croak "required option 'pid' is missing";
1095 1220
1096 $PID_CB{$pid}{$arg{cb}} = $arg{cb}; 1221 $PID_CB{$pid}{$arg{cb}} = $arg{cb};
1097 1222
1098 unless ($WNOHANG) {
1099 $WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; 1223 $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1100 }
1101 1224
1102 unless ($CHLD_W) { 1225 unless ($CHLD_W) {
1103 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); 1226 $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1104 # 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
1105 &_sigchld; 1228 &_sigchld;
1106 } 1229 }
1107 1230
1108 bless [$pid, $arg{cb}], "AnyEvent::Base::Child" 1231 bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1109} 1232}
1110 1233
1111sub AnyEvent::Base::Child::DESTROY { 1234sub AnyEvent::Base::child::DESTROY {
1112 my ($pid, $cb) = @{$_[0]}; 1235 my ($pid, $cb) = @{$_[0]};
1113 1236
1114 delete $PID_CB{$pid}{$cb}; 1237 delete $PID_CB{$pid}{$cb};
1115 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; 1238 delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1116 1239
1117 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 $${$_[0]};
1118} 1277}
1119 1278
1120package AnyEvent::CondVar; 1279package AnyEvent::CondVar;
1121 1280
1122our @ISA = AnyEvent::CondVar::Base::; 1281our @ISA = AnyEvent::CondVar::Base::;
1174} 1333}
1175 1334
1176# undocumented/compatibility with pre-3.4 1335# undocumented/compatibility with pre-3.4
1177*broadcast = \&send; 1336*broadcast = \&send;
1178*wait = \&_wait; 1337*wait = \&_wait;
1338
1339=head1 ERROR AND EXCEPTION HANDLING
1340
1341In general, AnyEvent does not do any error handling - it relies on the
1342caller to do that if required. The L<AnyEvent::Strict> module (see also
1343the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
1344checking of all AnyEvent methods, however, which is highly useful during
1345development.
1346
1347As for exception handling (i.e. runtime errors and exceptions thrown while
1348executing a callback), this is not only highly event-loop specific, but
1349also not in any way wrapped by this module, as this is the job of the main
1350program.
1351
1352The pure perl event loop simply re-throws the exception (usually
1353within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1354$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1355so on.
1356
1357=head1 ENVIRONMENT VARIABLES
1358
1359The following environment variables are used by this module or its
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.
1365
1366=over 4
1367
1368=item C<PERL_ANYEVENT_VERBOSE>
1369
1370By default, AnyEvent will be completely silent except in fatal
1371conditions. You can set this environment variable to make AnyEvent more
1372talkative.
1373
1374When set to C<1> or higher, causes AnyEvent to warn about unexpected
1375conditions, such as not being able to load the event model specified by
1376C<PERL_ANYEVENT_MODEL>.
1377
1378When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1379model it chooses.
1380
1381=item C<PERL_ANYEVENT_STRICT>
1382
1383AnyEvent does not do much argument checking by default, as thorough
1384argument checking is very costly. Setting this variable to a true value
1385will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1386check the arguments passed to most method calls. If it finds any problems,
1387it will croak.
1388
1389In other words, enables "strict" mode.
1390
1391Unlike C<use strict>, it is definitely recommended to keep it off in
1392production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
1393developing programs can be very useful, however.
1394
1395=item C<PERL_ANYEVENT_MODEL>
1396
1397This can be used to specify the event model to be used by AnyEvent, before
1398auto detection and -probing kicks in. It must be a string consisting
1399entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1400and the resulting module name is loaded and if the load was successful,
1401used as event model. If it fails to load AnyEvent will proceed with
1402auto detection and -probing.
1403
1404This functionality might change in future versions.
1405
1406For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1407could start your program like this:
1408
1409 PERL_ANYEVENT_MODEL=Perl perl ...
1410
1411=item C<PERL_ANYEVENT_PROTOCOLS>
1412
1413Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1414for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1415of auto probing).
1416
1417Must be set to a comma-separated list of protocols or address families,
1418current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1419used, and preference will be given to protocols mentioned earlier in the
1420list.
1421
1422This variable can effectively be used for denial-of-service attacks
1423against local programs (e.g. when setuid), although the impact is likely
1424small, as the program has to handle conenction and other failures anyways.
1425
1426Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1427but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1428- only support IPv4, never try to resolve or contact IPv6
1429addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1430IPv6, but prefer IPv6 over IPv4.
1431
1432=item C<PERL_ANYEVENT_EDNS0>
1433
1434Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1435for DNS. This extension is generally useful to reduce DNS traffic, but
1436some (broken) firewalls drop such DNS packets, which is why it is off by
1437default.
1438
1439Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1440EDNS0 in its DNS requests.
1441
1442=item C<PERL_ANYEVENT_MAX_FORKS>
1443
1444The maximum number of child processes that C<AnyEvent::Util::fork_call>
1445will create in parallel.
1446
1447=back
1179 1448
1180=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE 1449=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1181 1450
1182This is an advanced topic that you do not normally need to use AnyEvent in 1451This is an advanced topic that you do not normally need to use AnyEvent in
1183a module. This section is only of use to event loop authors who want to 1452a module. This section is only of use to event loop authors who want to
1217 1486
1218I<rxvt-unicode> also cheats a bit by not providing blocking access to 1487I<rxvt-unicode> also cheats a bit by not providing blocking access to
1219condition variables: code blocking while waiting for a condition will 1488condition variables: code blocking while waiting for a condition will
1220C<die>. This still works with most modules/usages, and blocking calls must 1489C<die>. This still works with most modules/usages, and blocking calls must
1221not be done in an interactive application, so it makes sense. 1490not be done in an interactive application, so it makes sense.
1222
1223=head1 ENVIRONMENT VARIABLES
1224
1225The following environment variables are used by this module:
1226
1227=over 4
1228
1229=item C<PERL_ANYEVENT_VERBOSE>
1230
1231By default, AnyEvent will be completely silent except in fatal
1232conditions. You can set this environment variable to make AnyEvent more
1233talkative.
1234
1235When set to C<1> or higher, causes AnyEvent to warn about unexpected
1236conditions, such as not being able to load the event model specified by
1237C<PERL_ANYEVENT_MODEL>.
1238
1239When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1240model it chooses.
1241
1242=item C<PERL_ANYEVENT_STRICT>
1243
1244AnyEvent does not do much argument checking by default, as thorough
1245argument checking is very costly. Setting this variable to a true value
1246will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1247check the arguments passed to most method calls. If it finds any problems
1248it will croak.
1249
1250In other words, enables "strict" mode.
1251
1252Unlike C<use strict> it is definitely recommended ot keep it off in
1253production.
1254
1255=item C<PERL_ANYEVENT_MODEL>
1256
1257This can be used to specify the event model to be used by AnyEvent, before
1258auto detection and -probing kicks in. It must be a string consisting
1259entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1260and the resulting module name is loaded and if the load was successful,
1261used as event model. If it fails to load AnyEvent will proceed with
1262auto detection and -probing.
1263
1264This functionality might change in future versions.
1265
1266For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1267could start your program like this:
1268
1269 PERL_ANYEVENT_MODEL=Perl perl ...
1270
1271=item C<PERL_ANYEVENT_PROTOCOLS>
1272
1273Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1274for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1275of auto probing).
1276
1277Must be set to a comma-separated list of protocols or address families,
1278current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1279used, and preference will be given to protocols mentioned earlier in the
1280list.
1281
1282This variable can effectively be used for denial-of-service attacks
1283against local programs (e.g. when setuid), although the impact is likely
1284small, as the program has to handle connection errors already-
1285
1286Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1287but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1288- only support IPv4, never try to resolve or contact IPv6
1289addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1290IPv6, but prefer IPv6 over IPv4.
1291
1292=item C<PERL_ANYEVENT_EDNS0>
1293
1294Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1295for DNS. This extension is generally useful to reduce DNS traffic, but
1296some (broken) firewalls drop such DNS packets, which is why it is off by
1297default.
1298
1299Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1300EDNS0 in its DNS requests.
1301
1302=item C<PERL_ANYEVENT_MAX_FORKS>
1303
1304The maximum number of child processes that C<AnyEvent::Util::fork_call>
1305will create in parallel.
1306
1307=back
1308 1491
1309=head1 EXAMPLE PROGRAM 1492=head1 EXAMPLE PROGRAM
1310 1493
1311The following program uses an I/O watcher to read data from STDIN, a timer 1494The following program uses an I/O watcher to read data from STDIN, a timer
1312to display a message once per second, and a condition variable to quit the 1495to display a message once per second, and a condition variable to quit the
1506watcher. 1689watcher.
1507 1690
1508=head3 Results 1691=head3 Results
1509 1692
1510 name watchers bytes create invoke destroy comment 1693 name watchers bytes create invoke destroy comment
1511 EV/EV 400000 244 0.56 0.46 0.31 EV native interface 1694 EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1512 EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers 1695 EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1513 CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal 1696 CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1514 Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation 1697 Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1515 Event/Event 16000 516 31.88 31.30 0.85 Event native interface 1698 Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1516 Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers 1699 Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1517 Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour 1700 Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1518 Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers 1701 Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1519 POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event 1702 POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1520 POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select 1703 POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1521 1704
1522=head3 Discussion 1705=head3 Discussion
1523 1706
1524The benchmark does I<not> measure scalability of the event loop very 1707The benchmark does I<not> measure scalability of the event loop very
1525well. For example, a select-based event loop (such as the pure perl one) 1708well. For example, a select-based event loop (such as the pure perl one)
1726=item * C-based event loops perform very well with small number of 1909=item * C-based event loops perform very well with small number of
1727watchers, as the management overhead dominates. 1910watchers, as the management overhead dominates.
1728 1911
1729=back 1912=back
1730 1913
1914=head2 THE IO::Lambda BENCHMARK
1915
1916Recently I was told about the benchmark in the IO::Lambda manpage, which
1917could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
1918simply compares IO::Lambda with POE, and IO::Lambda looks better (which
1919shouldn't come as a surprise to anybody). As such, the benchmark is
1920fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
1921very optimal. But how would AnyEvent compare when used without the extra
1922baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
1923
1924The benchmark itself creates an echo-server, and then, for 500 times,
1925connects to the echo server, sends a line, waits for the reply, and then
1926creates the next connection. This is a rather bad benchmark, as it doesn't
1927test the efficiency of the framework or much non-blocking I/O, but it is a
1928benchmark nevertheless.
1929
1930 name runtime
1931 Lambda/select 0.330 sec
1932 + optimized 0.122 sec
1933 Lambda/AnyEvent 0.327 sec
1934 + optimized 0.138 sec
1935 Raw sockets/select 0.077 sec
1936 POE/select, components 0.662 sec
1937 POE/select, raw sockets 0.226 sec
1938 POE/select, optimized 0.404 sec
1939
1940 AnyEvent/select/nb 0.085 sec
1941 AnyEvent/EV/nb 0.068 sec
1942 +state machine 0.134 sec
1943
1944The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
1945benchmarks actually make blocking connects and use 100% blocking I/O,
1946defeating the purpose of an event-based solution. All of the newly
1947written AnyEvent benchmarks use 100% non-blocking connects (using
1948AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
1949resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
1950generally require a lot more bookkeeping and event handling than blocking
1951connects (which involve a single syscall only).
1952
1953The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
1954offers similar expressive power as POE and IO::Lambda, using conventional
1955Perl syntax. This means that both the echo server and the client are 100%
1956non-blocking, further placing it at a disadvantage.
1957
1958As you can see, the AnyEvent + EV combination even beats the
1959hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1960backend easily beats IO::Lambda and POE.
1961
1962And even the 100% non-blocking version written using the high-level (and
1963slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
1964large margin, even though it does all of DNS, tcp-connect and socket I/O
1965in a non-blocking way.
1966
1967The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1968F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1969part of the IO::lambda distribution and were used without any changes.
1970
1971
1972=head1 SIGNALS
1973
1974AnyEvent currently installs handlers for these signals:
1975
1976=over 4
1977
1978=item SIGCHLD
1979
1980A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1981emulation for event loops that do not support them natively. Also, some
1982event loops install a similar handler.
1983
1984If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
1985reset it to default, to avoid losing child exit statuses.
1986
1987=item SIGPIPE
1988
1989A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1990when AnyEvent gets loaded.
1991
1992The rationale for this is that AnyEvent users usually do not really depend
1993on SIGPIPE delivery (which is purely an optimisation for shell use, or
1994badly-written programs), but C<SIGPIPE> can cause spurious and rare
1995program exits as a lot of people do not expect C<SIGPIPE> when writing to
1996some random socket.
1997
1998The rationale for installing a no-op handler as opposed to ignoring it is
1999that this way, the handler will be restored to defaults on exec.
2000
2001Feel free to install your own handler, or reset it to defaults.
2002
2003=back
2004
2005=cut
2006
2007undef $SIG{CHLD}
2008 if $SIG{CHLD} eq 'IGNORE';
2009
2010$SIG{PIPE} = sub { }
2011 unless defined $SIG{PIPE};
1731 2012
1732=head1 FORK 2013=head1 FORK
1733 2014
1734Most event libraries are not fork-safe. The ones who are usually are 2015Most event libraries are not fork-safe. The ones who are usually are
1735because they rely on inefficient but fork-safe C<select> or C<poll> 2016because they rely on inefficient but fork-safe C<select> or C<poll>
1756 use AnyEvent; 2037 use AnyEvent;
1757 2038
1758Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can 2039Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1759be used to probe what backend is used and gain other information (which is 2040be used to probe what backend is used and gain other information (which is
1760probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and 2041probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1761$ENV{PERL_ANYEGENT_STRICT}. 2042$ENV{PERL_ANYEVENT_STRICT}.
2043
2044Note that AnyEvent will remove I<all> environment variables starting with
2045C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
2046enabled.
1762 2047
1763 2048
1764=head1 BUGS 2049=head1 BUGS
1765 2050
1766Perl 5.8 has numerous memleaks that sometimes hit this module and are hard 2051Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1767to work around. If you suffer from memleaks, first upgrade to Perl 5.10 2052to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1768and check wether the leaks still show up. (Perl 5.10.0 has other annoying 2053and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1769mamleaks, such as leaking on C<map> and C<grep> but it is usually not as 2054memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1770pronounced). 2055pronounced).
1771 2056
1772 2057
1773=head1 SEE ALSO 2058=head1 SEE ALSO
1774 2059

Diff Legend

Removed lines
+ Added lines
< Changed lines
> Changed lines