[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.168 by root, Tue Jul 8 23:53:37 2008 UTC vs.
Revision 1.215 by root, Tue Jun 23 12:19:33 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event 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 { ... });
		14
		15	# one-shot or repeating timers
		16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		18
		19	print AnyEvent->now; # prints current event loop time
		20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		21
		22	# POSIX signal
		23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		24
		25	# child process exit
		26	my $w = AnyEvent->child (pid => $pid, cb => sub {
		27	my ($pid, $status) = @_;
12	...	28	...
13	});	29	});
14		30
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	31	# called when event loop idle (if applicable)
16	...	32	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		33
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
		37	# use a condvar in callback mode:
		38	$w->cb (sub { $_[0]->recv });
22		39
23	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
24		41
25	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
128	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
131	is in control).	148	is in control).
132		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		152	callbacks must not C<die> >>. The former is good programming practise in
		153	Perl and the latter stems from the fact that exception handling differs
		154	widely between event loops.
		155
133	To disable the watcher you have to destroy it (e.g. by setting the	156	To disable the watcher you have to destroy it (e.g. by setting the
134	variable you store it in to C<undef> or otherwise deleting all references	157	variable you store it in to C<undef> or otherwise deleting all references
135	to it).	158	to it).
136		159
137	All watchers are created by calling a method on the C<AnyEvent> class.	160	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
153	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
154		177
155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
156	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
157		180
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
159	(AnyEvent might or might not keep a reference to this file handle). C<poll>	182	for events (AnyEvent might or might not keep a reference to this file
		183	handle). Note that only file handles pointing to things for which
		184	non-blocking operation makes sense are allowed. This includes sockets,
		185	most character devices, pipes, fifos and so on, but not for example files
		186	or block devices.
		187
160	must be a string that is either C<r> or C<w>, which creates a watcher	188	C<poll> must be a string that is either C<r> or C<w>, which creates a
161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	189	watcher waiting for "r"eadable or "w"ritable events, respectively.
		190
162	callback to invoke each time the file handle becomes ready.	191	C<cb> is the callback to invoke each time the file handle becomes ready.
163		192
164	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
167		196
…		…
299	In either case, if you care (and in most cases, you don't), then you	328	In either case, if you care (and in most cases, you don't), then you
300	can get whatever behaviour you want with any event loop, by taking the	329	can get whatever behaviour you want with any event loop, by taking the
301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
302	account.	331	account.
303		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
304	=back	348	=back
305		349
306	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
307		351
308	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
331	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
332		376
333	You can also watch on a child process exit and catch its exit status.	377	You can also watch on a child process exit and catch its exit status.
334		378
335	The child process is specified by the C<pid> argument (if set to C<0>, it	379	The child process is specified by the C<pid> argument (if set to C<0>, it
336	watches for any child process exit). The watcher will trigger as often	380	watches for any child process exit). The watcher will triggered only when
337	as status change for the child are received. This works by installing a	381	the child process has finished and an exit status is available, not on
338	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
339	and exit status (as returned by waitpid), so unlike other watcher types,	383
340	you I<can> rely on child watcher callback arguments.	384	The callback will be called with the pid and exit status (as returned by
		385	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		386	callback arguments.
		387
		388	This watcher type works by installing a signal handler for C<SIGCHLD>,
		389	and since it cannot be shared, nothing else should use SIGCHLD or reap
		390	random child processes (waiting for specific child processes, e.g. inside
		391	C<system>, is just fine).
341		392
342	There is a slight catch to child watchers, however: you usually start them	393	There is a slight catch to child watchers, however: you usually start them
343	I<after> the child process was created, and this means the process could	394	I<after> the child process was created, and this means the process could
344	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
345		396
…		…
367	);	418	);
368		419
369	# do something else, then wait for process exit	420	# do something else, then wait for process exit
370	$done->recv;	421	$done->recv;
371		422
		423	=head2 IDLE WATCHERS
		424
		425	Sometimes there is a need to do something, but it is not so important
		426	to do it instantly, but only when there is nothing better to do. This
		427	"nothing better to do" is usually defined to be "no other events need
		428	attention by the event loop".
		429
		430	Idle watchers ideally get invoked when the event loop has nothing
		431	better to do, just before it would block the process to wait for new
		432	events. Instead of blocking, the idle watcher is invoked.
		433
		434	Most event loops unfortunately do not really support idle watchers (only
		435	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		436	will simply call the callback "from time to time".
		437
		438	Example: read lines from STDIN, but only process them when the
		439	program is otherwise idle:
		440
		441	my @lines; # read data
		442	my $idle_w;
		443	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		444	push @lines, scalar <STDIN>;
		445
		446	# start an idle watcher, if not already done
		447	$idle_w \|\|= AnyEvent->idle (cb => sub {
		448	# handle only one line, when there are lines left
		449	if (my $line = shift @lines) {
		450	print "handled when idle: $line";
		451	} else {
		452	# otherwise disable the idle watcher again
		453	undef $idle_w;
		454	}
		455	});
		456	});
		457
372	=head2 CONDITION VARIABLES	458	=head2 CONDITION VARIABLES
373		459
374	If you are familiar with some event loops you will know that all of them	460	If you are familiar with some event loops you will know that all of them
375	require you to run some blocking "loop", "run" or similar function that	461	require you to run some blocking "loop", "run" or similar function that
376	will actively watch for new events and call your callbacks.	462	will actively watch for new events and call your callbacks.
…		…
381	The instrument to do that is called a "condition variable", so called	467	The instrument to do that is called a "condition variable", so called
382	because they represent a condition that must become true.	468	because they represent a condition that must become true.
383		469
384	Condition variables can be created by calling the C<< AnyEvent->condvar	470	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	471	>> method, usually without arguments. The only argument pair allowed is
		472
386	C<cb>, which specifies a callback to be called when the condition variable	473	C<cb>, which specifies a callback to be called when the condition variable
387	becomes true.	474	becomes true, with the condition variable as the first argument (but not
		475	the results).
388		476
389	After creation, the condition variable is "false" until it becomes "true"	477	After creation, the condition variable is "false" until it becomes "true"
390	by calling the C<send> method (or calling the condition variable as if it	478	by calling the C<send> method (or calling the condition variable as if it
391	were a callback, read about the caveats in the description for the C<<	479	were a callback, read about the caveats in the description for the C<<
392	->send >> method).	480	->send >> method).
…		…
448		536
449	my $done = AnyEvent->condvar;	537	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	538	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	539	$done->recv;
452		540
		541	Example: Imagine an API that returns a condvar and doesn't support
		542	callbacks. This is how you make a synchronous call, for example from
		543	the main program:
		544
		545	use AnyEvent::CouchDB;
		546
		547	...
		548
		549	my @info = $couchdb->info->recv;
		550
		551	And this is how you would just ste a callback to be called whenever the
		552	results are available:
		553
		554	$couchdb->info->cb (sub {
		555	my @info = $_[0]->recv;
		556	});
		557
453	=head3 METHODS FOR PRODUCERS	558	=head3 METHODS FOR PRODUCERS
454		559
455	These methods should only be used by the producing side, i.e. the	560	These methods should only be used by the producing side, i.e. the
456	code/module that eventually sends the signal. Note that it is also	561	code/module that eventually sends the signal. Note that it is also
457	the producer side which creates the condvar in most cases, but it isn't	562	the producer side which creates the condvar in most cases, but it isn't
…		…
590	=item $bool = $cv->ready	695	=item $bool = $cv->ready
591		696
592	Returns true when the condition is "true", i.e. whether C<send> or	697	Returns true when the condition is "true", i.e. whether C<send> or
593	C<croak> have been called.	698	C<croak> have been called.
594		699
595	=item $cb = $cv->cb ([new callback])	700	=item $cb = $cv->cb ($cb->($cv))
596		701
597	This is a mutator function that returns the callback set and optionally	702	This is a mutator function that returns the callback set and optionally
598	replaces it before doing so.	703	replaces it before doing so.
599		704
600	The callback will be called when the condition becomes "true", i.e. when	705	The callback will be called when the condition becomes "true", i.e. when
…		…
790	=item L<AnyEvent::IGS>	895	=item L<AnyEvent::IGS>
791		896
792	A non-blocking interface to the Internet Go Server protocol (used by	897	A non-blocking interface to the Internet Go Server protocol (used by
793	L<App::IGS>).	898	L<App::IGS>).
794		899
795	=item L<Net::IRC3>	900	=item L<AnyEvent::IRC>
796		901
797	AnyEvent based IRC client module family.	902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
798		903
799	=item L<Net::XMPP2>	904	=item L<Net::XMPP2>
800		905
801	AnyEvent based XMPP (Jabber protocol) module family.	906	AnyEvent based XMPP (Jabber protocol) module family.
802		907
…		…
822	=cut	927	=cut
823		928
824	package AnyEvent;	929	package AnyEvent;
825		930
826	no warnings;	931	no warnings;
827	use strict;	932	use strict qw(vars subs);
828		933
829	use Carp;	934	use Carp;
830		935
831	our $VERSION = 4.2;	936	our $VERSION = 4.411;
832	our $MODEL;	937	our $MODEL;
833		938
834	our $AUTOLOAD;	939	our $AUTOLOAD;
835	our @ISA;	940	our @ISA;
836		941
837	our @REGISTRY;	942	our @REGISTRY;
838		943
839	our $WIN32;	944	our $WIN32;
840		945
841	BEGIN {	946	BEGIN {
842	my $win32 = ! ! ($^O =~ /mswin32/i);	947	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
843	eval "sub WIN32(){ $win32 }";	948	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		949
		950	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		951	if ${^TAINT};
844	}	952	}
845		953
846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	954	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
847		955
848	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	956	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	976	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
869	[Wx:: => AnyEvent::Impl::POE::],	977	[Wx:: => AnyEvent::Impl::POE::],
870	[Prima:: => AnyEvent::Impl::POE::],	978	[Prima:: => AnyEvent::Impl::POE::],
871	);	979	);
872		980
873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	981	our %method = map +($_ => 1),
		982	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
874		983
875	our @post_detect;	984	our @post_detect;
876		985
877	sub post_detect(&) {	986	sub post_detect(&) {
878	my ($cb) = @_;	987	my ($cb) = @_;
…		…
883	1	992	1
884	} else {	993	} else {
885	push @post_detect, $cb;	994	push @post_detect, $cb;
886		995
887	defined wantarray	996	defined wantarray
888	? bless \$cb, "AnyEvent::Util::PostDetect"	997	? bless \$cb, "AnyEvent::Util::postdetect"
889	: ()	998	: ()
890	}	999	}
891	}	1000	}
892		1001
893	sub AnyEvent::Util::PostDetect::DESTROY {	1002	sub AnyEvent::Util::postdetect::DESTROY {
894	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1003	@post_detect = grep $_ != ${$_[0]}, @post_detect;
895	}	1004	}
896		1005
897	sub detect() {	1006	sub detect() {
898	unless ($MODEL) {	1007	unless ($MODEL) {
…		…
935	last;	1044	last;
936	}	1045	}
937	}	1046	}
938		1047
939	$MODEL	1048	$MODEL
940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1049	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
941	}	1050	}
942	}	1051	}
943		1052
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1053	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
945		1054
…		…
963		1072
964	my $class = shift;	1073	my $class = shift;
965	$class->$func (@_);	1074	$class->$func (@_);
966	}	1075	}
967		1076
		1077	# utility function to dup a filehandle. this is used by many backends
		1078	# to support binding more than one watcher per filehandle (they usually
		1079	# allow only one watcher per fd, so we dup it to get a different one).
		1080	sub _dupfh($$$$) {
		1081	my ($poll, $fh, $r, $w) = @_;
		1082
		1083	# cygwin requires the fh mode to be matching, unix doesn't
		1084	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1085	: $poll eq "w" ? ($w, ">")
		1086	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1087
		1088	open my $fh2, "$mode&" . fileno $fh
		1089	or die "cannot dup() filehandle: $!,";
		1090
		1091	# we assume CLOEXEC is already set by perl in all important cases
		1092
		1093	($fh2, $rw)
		1094	}
		1095
968	package AnyEvent::Base;	1096	package AnyEvent::Base;
969		1097
970	# default implementation for now and time	1098	# default implementations for many methods
971		1099
972	use Time::HiRes ();	1100	BEGIN {
		1101	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1102	*_time = \&Time::HiRes::time;
		1103	# if (eval "use POSIX (); (POSIX::times())...
		1104	} else {
		1105	*_time = sub { time }; # epic fail
		1106	}
		1107	}
973		1108
974	sub time { Time::HiRes::time }	1109	sub time { _time }
975	sub now { Time::HiRes::time }	1110	sub now { _time }
		1111	sub now_update { }
976		1112
977	# default implementation for ->condvar	1113	# default implementation for ->condvar
978		1114
979	sub condvar {	1115	sub condvar {
980	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1116	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
981	}	1117	}
982		1118
983	# default implementation for ->signal	1119	# default implementation for ->signal
984		1120
985	our %SIG_CB;	1121	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1122
		1123	sub _signal_exec {
		1124	sysread $SIGPIPE_R, my $dummy, 4;
		1125
		1126	while (%SIG_EV) {
		1127	for (keys %SIG_EV) {
		1128	delete $SIG_EV{$_};
		1129	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1130	}
		1131	}
		1132	}
986		1133
987	sub signal {	1134	sub signal {
988	my (undef, %arg) = @_;	1135	my (undef, %arg) = @_;
989		1136
		1137	unless ($SIGPIPE_R) {
		1138	require Fcntl;
		1139
		1140	if (AnyEvent::WIN32) {
		1141	require AnyEvent::Util;
		1142
		1143	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1144	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1145	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1146	} else {
		1147	pipe $SIGPIPE_R, $SIGPIPE_W;
		1148	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1149	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1150
		1151	# not strictly required, as $^F is normally 2, but let's make sure...
		1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1154	}
		1155
		1156	$SIGPIPE_R
		1157	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1158
		1159	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1160	}
		1161
990	my $signal = uc $arg{signal}	1162	my $signal = uc $arg{signal}
991	or Carp::croak "required option 'signal' is missing";	1163	or Carp::croak "required option 'signal' is missing";
992		1164
993	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1165	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
994	$SIG{$signal} \|\|= sub {	1166	$SIG{$signal} \|\|= sub {
995	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1167	local $!;
		1168	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1169	undef $SIG_EV{$signal};
996	};	1170	};
997		1171
998	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1172	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
999	}	1173	}
1000		1174
1001	sub AnyEvent::Base::Signal::DESTROY {	1175	sub AnyEvent::Base::signal::DESTROY {
1002	my ($signal, $cb) = @{$_[0]};	1176	my ($signal, $cb) = @{$_[0]};
1003		1177
1004	delete $SIG_CB{$signal}{$cb};	1178	delete $SIG_CB{$signal}{$cb};
1005		1179
		1180	# delete doesn't work with older perls - they then
		1181	# print weird messages, or just unconditionally exit
		1182	# instead of getting the default action.
1006	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1183	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1007	}	1184	}
1008		1185
1009	# default implementation for ->child	1186	# default implementation for ->child
1010		1187
1011	our %PID_CB;	1188	our %PID_CB;
1012	our $CHLD_W;	1189	our $CHLD_W;
1013	our $CHLD_DELAY_W;	1190	our $CHLD_DELAY_W;
1014	our $PID_IDLE;
1015	our $WNOHANG;	1191	our $WNOHANG;
1016		1192
1017	sub _child_wait {	1193	sub _sigchld {
1018	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1194	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1019	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1195	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1020	(values %{ $PID_CB{0} \|\| {} });	1196	(values %{ $PID_CB{0} \|\| {} });
1021	}	1197	}
1022
1023	undef $PID_IDLE;
1024	}
1025
1026	sub _sigchld {
1027	# make sure we deliver these changes "synchronous" with the event loop.
1028	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1029	undef $CHLD_DELAY_W;
1030	&_child_wait;
1031	});
1032	}	1198	}
1033		1199
1034	sub child {	1200	sub child {
1035	my (undef, %arg) = @_;	1201	my (undef, %arg) = @_;
1036		1202
1037	defined (my $pid = $arg{pid} + 0)	1203	defined (my $pid = $arg{pid} + 0)
1038	or Carp::croak "required option 'pid' is missing";	1204	or Carp::croak "required option 'pid' is missing";
1039		1205
1040	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1206	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1041		1207
1042	unless ($WNOHANG) {
1043	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1208	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1044	}
1045		1209
1046	unless ($CHLD_W) {	1210	unless ($CHLD_W) {
1047	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1211	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1048	# child could be a zombie already, so make at least one round	1212	# child could be a zombie already, so make at least one round
1049	&_sigchld;	1213	&_sigchld;
1050	}	1214	}
1051		1215
1052	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1216	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1053	}	1217	}
1054		1218
1055	sub AnyEvent::Base::Child::DESTROY {	1219	sub AnyEvent::Base::child::DESTROY {
1056	my ($pid, $cb) = @{$_[0]};	1220	my ($pid, $cb) = @{$_[0]};
1057		1221
1058	delete $PID_CB{$pid}{$cb};	1222	delete $PID_CB{$pid}{$cb};
1059	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1223	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1060		1224
1061	undef $CHLD_W unless keys %PID_CB;	1225	undef $CHLD_W unless keys %PID_CB;
		1226	}
		1227
		1228	# idle emulation is done by simply using a timer, regardless
		1229	# of whether the process is idle or not, and not letting
		1230	# the callback use more than 50% of the time.
		1231	sub idle {
		1232	my (undef, %arg) = @_;
		1233
		1234	my ($cb, $w, $rcb) = $arg{cb};
		1235
		1236	$rcb = sub {
		1237	if ($cb) {
		1238	$w = _time;
		1239	&$cb;
		1240	$w = _time - $w;
		1241
		1242	# never use more then 50% of the time for the idle watcher,
		1243	# within some limits
		1244	$w = 0.0001 if $w < 0.0001;
		1245	$w = 5 if $w > 5;
		1246
		1247	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1248	} else {
		1249	# clean up...
		1250	undef $w;
		1251	undef $rcb;
		1252	}
		1253	};
		1254
		1255	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1256
		1257	bless \\$cb, "AnyEvent::Base::idle"
		1258	}
		1259
		1260	sub AnyEvent::Base::idle::DESTROY {
		1261	undef $${$_[0]};
1062	}	1262	}
1063		1263
1064	package AnyEvent::CondVar;	1264	package AnyEvent::CondVar;
1065		1265
1066	our @ISA = AnyEvent::CondVar::Base::;	1266	our @ISA = AnyEvent::CondVar::Base::;
…		…
1118	}	1318	}
1119		1319
1120	# undocumented/compatibility with pre-3.4	1320	# undocumented/compatibility with pre-3.4
1121	*broadcast = \&send;	1321	*broadcast = \&send;
1122	*wait = \&_wait;	1322	*wait = \&_wait;
		1323
		1324	=head1 ERROR AND EXCEPTION HANDLING
		1325
		1326	In general, AnyEvent does not do any error handling - it relies on the
		1327	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1328	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1329	checking of all AnyEvent methods, however, which is highly useful during
		1330	development.
		1331
		1332	As for exception handling (i.e. runtime errors and exceptions thrown while
		1333	executing a callback), this is not only highly event-loop specific, but
		1334	also not in any way wrapped by this module, as this is the job of the main
		1335	program.
		1336
		1337	The pure perl event loop simply re-throws the exception (usually
		1338	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1339	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1340	so on.
		1341
		1342	=head1 ENVIRONMENT VARIABLES
		1343
		1344	The following environment variables are used by this module or its
		1345	submodules.
		1346
		1347	Note that AnyEvent will remove I<all> environment variables starting with
		1348	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1349	enabled.
		1350
		1351	=over 4
		1352
		1353	=item C<PERL_ANYEVENT_VERBOSE>
		1354
		1355	By default, AnyEvent will be completely silent except in fatal
		1356	conditions. You can set this environment variable to make AnyEvent more
		1357	talkative.
		1358
		1359	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1360	conditions, such as not being able to load the event model specified by
		1361	C<PERL_ANYEVENT_MODEL>.
		1362
		1363	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1364	model it chooses.
		1365
		1366	=item C<PERL_ANYEVENT_STRICT>
		1367
		1368	AnyEvent does not do much argument checking by default, as thorough
		1369	argument checking is very costly. Setting this variable to a true value
		1370	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1371	check the arguments passed to most method calls. If it finds any problems
		1372	it will croak.
		1373
		1374	In other words, enables "strict" mode.
		1375
		1376	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1377	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1378	developing programs can be very useful, however.
		1379
		1380	=item C<PERL_ANYEVENT_MODEL>
		1381
		1382	This can be used to specify the event model to be used by AnyEvent, before
		1383	auto detection and -probing kicks in. It must be a string consisting
		1384	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1385	and the resulting module name is loaded and if the load was successful,
		1386	used as event model. If it fails to load AnyEvent will proceed with
		1387	auto detection and -probing.
		1388
		1389	This functionality might change in future versions.
		1390
		1391	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1392	could start your program like this:
		1393
		1394	PERL_ANYEVENT_MODEL=Perl perl ...
		1395
		1396	=item C<PERL_ANYEVENT_PROTOCOLS>
		1397
		1398	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1399	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1400	of auto probing).
		1401
		1402	Must be set to a comma-separated list of protocols or address families,
		1403	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1404	used, and preference will be given to protocols mentioned earlier in the
		1405	list.
		1406
		1407	This variable can effectively be used for denial-of-service attacks
		1408	against local programs (e.g. when setuid), although the impact is likely
		1409	small, as the program has to handle conenction and other failures anyways.
		1410
		1411	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1412	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1413	- only support IPv4, never try to resolve or contact IPv6
		1414	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1415	IPv6, but prefer IPv6 over IPv4.
		1416
		1417	=item C<PERL_ANYEVENT_EDNS0>
		1418
		1419	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1420	for DNS. This extension is generally useful to reduce DNS traffic, but
		1421	some (broken) firewalls drop such DNS packets, which is why it is off by
		1422	default.
		1423
		1424	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1425	EDNS0 in its DNS requests.
		1426
		1427	=item C<PERL_ANYEVENT_MAX_FORKS>
		1428
		1429	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1430	will create in parallel.
		1431
		1432	=back
1123		1433
1124	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1434	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1125		1435
1126	This is an advanced topic that you do not normally need to use AnyEvent in	1436	This is an advanced topic that you do not normally need to use AnyEvent in
1127	a module. This section is only of use to event loop authors who want to	1437	a module. This section is only of use to event loop authors who want to
…		…
1161		1471
1162	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1472	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1163	condition variables: code blocking while waiting for a condition will	1473	condition variables: code blocking while waiting for a condition will
1164	C<die>. This still works with most modules/usages, and blocking calls must	1474	C<die>. This still works with most modules/usages, and blocking calls must
1165	not be done in an interactive application, so it makes sense.	1475	not be done in an interactive application, so it makes sense.
1166
1167	=head1 ENVIRONMENT VARIABLES
1168
1169	The following environment variables are used by this module:
1170
1171	=over 4
1172
1173	=item C<PERL_ANYEVENT_VERBOSE>
1174
1175	By default, AnyEvent will be completely silent except in fatal
1176	conditions. You can set this environment variable to make AnyEvent more
1177	talkative.
1178
1179	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1180	conditions, such as not being able to load the event model specified by
1181	C<PERL_ANYEVENT_MODEL>.
1182
1183	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1184	model it chooses.
1185
1186	=item C<PERL_ANYEVENT_STRICT>
1187
1188	AnyEvent does not do much argument checking by default, as thorough
1189	argument checking is very costly. Setting this variable to a true value
1190	will cause AnyEvent to thoroughly check the arguments passed to most
1191	method calls and croaks if it finds any problems. In other words, enables
1192	"strict" mode. Unlike C<use strict> it is definitely recommended ot keep
1193	it off in production.
1194
1195	=item C<PERL_ANYEVENT_MODEL>
1196
1197	This can be used to specify the event model to be used by AnyEvent, before
1198	auto detection and -probing kicks in. It must be a string consisting
1199	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1200	and the resulting module name is loaded and if the load was successful,
1201	used as event model. If it fails to load AnyEvent will proceed with
1202	auto detection and -probing.
1203
1204	This functionality might change in future versions.
1205
1206	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1207	could start your program like this:
1208
1209	PERL_ANYEVENT_MODEL=Perl perl ...
1210
1211	=item C<PERL_ANYEVENT_PROTOCOLS>
1212
1213	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1214	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1215	of auto probing).
1216
1217	Must be set to a comma-separated list of protocols or address families,
1218	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1219	used, and preference will be given to protocols mentioned earlier in the
1220	list.
1221
1222	This variable can effectively be used for denial-of-service attacks
1223	against local programs (e.g. when setuid), although the impact is likely
1224	small, as the program has to handle connection errors already-
1225
1226	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1227	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1228	- only support IPv4, never try to resolve or contact IPv6
1229	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1230	IPv6, but prefer IPv6 over IPv4.
1231
1232	=item C<PERL_ANYEVENT_EDNS0>
1233
1234	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1235	for DNS. This extension is generally useful to reduce DNS traffic, but
1236	some (broken) firewalls drop such DNS packets, which is why it is off by
1237	default.
1238
1239	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1240	EDNS0 in its DNS requests.
1241
1242	=item C<PERL_ANYEVENT_MAX_FORKS>
1243
1244	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1245	will create in parallel.
1246
1247	=back
1248		1476
1249	=head1 EXAMPLE PROGRAM	1477	=head1 EXAMPLE PROGRAM
1250		1478
1251	The following program uses an I/O watcher to read data from STDIN, a timer	1479	The following program uses an I/O watcher to read data from STDIN, a timer
1252	to display a message once per second, and a condition variable to quit the	1480	to display a message once per second, and a condition variable to quit the
…		…
1446	watcher.	1674	watcher.
1447		1675
1448	=head3 Results	1676	=head3 Results
1449		1677
1450	name watchers bytes create invoke destroy comment	1678	name watchers bytes create invoke destroy comment
1451	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1679	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1452	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1680	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1453	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1681	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1454	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1682	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1455	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1683	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1456	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1684	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1457	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1685	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1458	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1686	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1459	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1687	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1460	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1688	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1461		1689
1462	=head3 Discussion	1690	=head3 Discussion
1463		1691
1464	The benchmark does I<not> measure scalability of the event loop very	1692	The benchmark does I<not> measure scalability of the event loop very
1465	well. For example, a select-based event loop (such as the pure perl one)	1693	well. For example, a select-based event loop (such as the pure perl one)
…		…
1666	=item * C-based event loops perform very well with small number of	1894	=item * C-based event loops perform very well with small number of
1667	watchers, as the management overhead dominates.	1895	watchers, as the management overhead dominates.
1668		1896
1669	=back	1897	=back
1670		1898
		1899	=head2 THE IO::Lambda BENCHMARK
		1900
		1901	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1902	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1903	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		1904	shouldn't come as a surprise to anybody). As such, the benchmark is
		1905	fine, and shows that the AnyEvent backend from IO::Lambda isn't very
		1906	optimal. But how would AnyEvent compare when used without the extra
		1907	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		1908
		1909	The benchmark itself creates an echo-server, and then, for 500 times,
		1910	connects to the echo server, sends a line, waits for the reply, and then
		1911	creates the next connection. This is a rather bad benchmark, as it doesn't
		1912	test the efficiency of the framework, but it is a benchmark nevertheless.
		1913
		1914	name runtime
		1915	Lambda/select 0.330 sec
		1916	+ optimized 0.122 sec
		1917	Lambda/AnyEvent 0.327 sec
		1918	+ optimized 0.138 sec
		1919	Raw sockets/select 0.077 sec
		1920	POE/select, components 0.662 sec
		1921	POE/select, raw sockets 0.226 sec
		1922	POE/select, optimized 0.404 sec
		1923
		1924	AnyEvent/select/nb 0.085 sec
		1925	AnyEvent/EV/nb 0.068 sec
		1926	+state machine 0.134 sec
		1927
		1928	The benchmark is also a bit unfair (my fault) - the IO::Lambda
		1929	benchmarks actually make blocking connects and use 100% blocking I/O,
		1930	defeating the purpose of an event-based solution. All of the newly
		1931	written AnyEvent benchmarks use 100% non-blocking connects (using
		1932	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		1933	resolver), so AnyEvent is at a disadvantage here as non-blocking connects
		1934	generally require a lot more bookkeeping and event handling than blocking
		1935	connects (which involve a single syscall only).
		1936
		1937	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		1938	offers similar expressive power as POE and IO::Lambda (using conventional
		1939	Perl syntax), which means both the echo server and the client are 100%
		1940	non-blocking w.r.t. I/O, further placing it at a disadvantage.
		1941
		1942	As you can see, AnyEvent + EV even beats the hand-optimised "raw sockets
		1943	benchmark", while AnyEvent + its pure perl backend easily beats
		1944	IO::Lambda and POE.
		1945
		1946	And even the 100% non-blocking version written using the high-level (and
		1947	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda,
		1948	even thought it does all of DNS, tcp-connect and socket I/O in a
		1949	non-blocking way.
		1950
		1951
		1952	=head1 SIGNALS
		1953
		1954	AnyEvent currently installs handlers for these signals:
		1955
		1956	=over 4
		1957
		1958	=item SIGCHLD
		1959
		1960	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1961	emulation for event loops that do not support them natively. Also, some
		1962	event loops install a similar handler.
		1963
		1964	=item SIGPIPE
		1965
		1966	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1967	when AnyEvent gets loaded.
		1968
		1969	The rationale for this is that AnyEvent users usually do not really depend
		1970	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1971	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1972	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1973	some random socket.
		1974
		1975	The rationale for installing a no-op handler as opposed to ignoring it is
		1976	that this way, the handler will be restored to defaults on exec.
		1977
		1978	Feel free to install your own handler, or reset it to defaults.
		1979
		1980	=back
		1981
		1982	=cut
		1983
		1984	$SIG{PIPE} = sub { }
		1985	unless defined $SIG{PIPE};
		1986
1671		1987
1672	=head1 FORK	1988	=head1 FORK
1673		1989
1674	Most event libraries are not fork-safe. The ones who are usually are	1990	Most event libraries are not fork-safe. The ones who are usually are
1675	because they rely on inefficient but fork-safe C<select> or C<poll>	1991	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1696	use AnyEvent;	2012	use AnyEvent;
1697		2013
1698	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2014	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1699	be used to probe what backend is used and gain other information (which is	2015	be used to probe what backend is used and gain other information (which is
1700	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2016	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1701	$ENV{PERL_ANYEGENT_STRICT}.	2017	$ENV{PERL_ANYEVENT_STRICT}.
1702		2018
1703		2019
1704	=head1 BUGS	2020	=head1 BUGS
1705		2021
1706	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2022	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1707	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2023	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1708	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2024	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1709	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2025	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1710	pronounced).	2026	pronounced).
1711		2027
1712		2028
1713	=head1 SEE ALSO	2029	=head1 SEE ALSO
1714		2030

Diff Legend

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

Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.168 by root, Tue Jul 8 23:53:37 2008 UTC vs. Revision 1.215 by root, Tue Jun 23 12:19:33 2009 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.168 by root, Tue Jul 8 23:53:37 2008 UTC vs.
Revision 1.215 by root, Tue Jun 23 12:19:33 2009 UTC