--- AnyEvent/lib/AnyEvent.pm 2009/07/09 08:31:16 1.234 +++ AnyEvent/lib/AnyEvent.pm 2010/05/20 23:55:51 1.324 @@ -1,15 +1,18 @@ =head1 NAME -AnyEvent - provide framework for multiple event loops +AnyEvent - the DBI of event loop programming -EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported -event loops. +EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt +and POE are various supported event loops/environments. =head1 SYNOPSIS use AnyEvent; - # file descriptor readable + # if you prefer function calls, look at the AE manpage for + # an alternative API. + + # file handle or descriptor readable my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... }); # one-shot or repeating timers @@ -43,6 +46,14 @@ in a tutorial or some gentle introduction, have a look at the L manpage. +=head1 SUPPORT + +There is a mailinglist for discussing all things AnyEvent, and an IRC +channel, too. + +See the AnyEvent project page at the B, at L, for more info. + =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) Glib, POE, IO::Async, Event... CPAN offers event models by the dozen @@ -175,6 +186,12 @@ =head2 I/O WATCHERS + $w = AnyEvent->io ( + fh => , + poll => <"r" or "w">, + cb => , + ); + You can create an I/O watcher by calling the C<< AnyEvent->io >> method with the following mandatory key-value pairs as arguments: @@ -213,6 +230,14 @@ =head2 TIME WATCHERS + $w = AnyEvent->timer (after => , cb => ); + + $w = AnyEvent->timer ( + after => , + interval => , + cb => , + ); + You can create a time watcher by calling the C<< AnyEvent->timer >> method with the following mandatory arguments: @@ -343,12 +368,21 @@ When this is the case, you can call this method, which will update the event loop's idea of "current time". +A typical example would be a script in a web server (e.g. C) - +when mod_perl executes the script, then the event loop will have the wrong +idea about the "current time" (being potentially far in the past, when the +script ran the last time). In that case you should arrange a call to C<< +AnyEvent->now_update >> each time the web server process wakes up again +(e.g. at the start of your script, or in a handler). + Note that updating the time I cause some events to be handled. =back =head2 SIGNAL WATCHERS + $w = AnyEvent->signal (signal => , cb => ); + You can watch for signals using a signal watcher, C is the signal I in uppercase and without any C prefix, C is the Perl callback to be invoked whenever a signal occurs. @@ -363,23 +397,65 @@ but it is guaranteed not to interrupt any other callbacks. The main advantage of using these watchers is that you can share a signal -between multiple watchers. +between multiple watchers, and AnyEvent will ensure that signals will not +interrupt your program at bad times. -This watcher might use C<%SIG>, so programs overwriting those signals -directly will likely not work correctly. +This watcher might use C<%SIG> (depending on the event loop used), +so programs overwriting those signals directly will likely not work +correctly. Example: exit on SIGINT my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); +=head3 Restart Behaviour + +While restart behaviour is up to the event loop implementation, most will +not restart syscalls (that includes L and AnyEvent's +pure perl implementation). + +=head3 Safe/Unsafe Signals + +Perl signals can be either "safe" (synchronous to opcode handling) or +"unsafe" (asynchronous) - the former might get delayed indefinitely, the +latter might corrupt your memory. + +AnyEvent signal handlers are, in addition, synchronous to the event loop, +i.e. they will not interrupt your running perl program but will only be +called as part of the normal event handling (just like timer, I/O etc. +callbacks, too). + +=head3 Signal Races, Delays and Workarounds + +Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching +callbacks to signals in a generic way, which is a pity, as you cannot +do race-free signal handling in perl, requiring C libraries for +this. AnyEvent will try to do it's best, which means in some cases, +signals will be delayed. The maximum time a signal might be delayed is +specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This +variable can be changed only before the first signal watcher is created, +and should be left alone otherwise. This variable determines how often +AnyEvent polls for signals (in case a wake-up was missed). Higher values +will cause fewer spurious wake-ups, which is better for power and CPU +saving. + +All these problems can be avoided by installing the optional +L module, which works with most event loops. It will not +work with inherently broken event loops such as L or L +(and not with L currently, as POE does it's own workaround with +one-second latency). For those, you just have to suffer the delays. + =head2 CHILD PROCESS WATCHERS + $w = AnyEvent->child (pid => , cb => ); + You can also watch on a child process exit and catch its exit status. -The child process is specified by the C argument (if set to C<0>, it -watches for any child process exit). The watcher will triggered only when -the child process has finished and an exit status is available, not on -any trace events (stopped/continued). +The child process is specified by the C argument (one some backends, +using C<0> watches for any child process exit, on others this will +croak). The watcher will be triggered only when the child process has +finished and an exit status is available, not on any trace events +(stopped/continued). The callback will be called with the pid and exit status (as returned by waitpid), so unlike other watcher types, you I rely on child watcher @@ -406,6 +482,10 @@ watcher before you C the child (alternatively, you can call C). +As most event loops do not support waiting for child events, they will be +emulated by AnyEvent in most cases, in which the latency and race problems +mentioned in the description of signal watchers apply. + Example: fork a process and wait for it my $done = AnyEvent->condvar; @@ -426,16 +506,21 @@ =head2 IDLE WATCHERS -Sometimes there is a need to do something, but it is not so important -to do it instantly, but only when there is nothing better to do. This -"nothing better to do" is usually defined to be "no other events need -attention by the event loop". - -Idle watchers ideally get invoked when the event loop has nothing -better to do, just before it would block the process to wait for new -events. Instead of blocking, the idle watcher is invoked. + $w = AnyEvent->idle (cb => ); -Most event loops unfortunately do not really support idle watchers (only +Repeatedly invoke the callback after the process becomes idle, until +either the watcher is destroyed or new events have been detected. + +Idle watchers are useful when there is a need to do something, but it +is not so important (or wise) to do it instantly. The callback will be +invoked only when there is "nothing better to do", which is usually +defined as "all outstanding events have been handled and no new events +have been detected". That means that idle watchers ideally get invoked +when the event loop has just polled for new events but none have been +detected. Instead of blocking to wait for more events, the idle watchers +will be invoked. + +Unfortunately, most event loops do not really support idle watchers (only EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent will simply call the callback "from time to time". @@ -461,19 +546,25 @@ =head2 CONDITION VARIABLES + $cv = AnyEvent->condvar; + + $cv->send (); + my @res = $cv->recv; + If you are familiar with some event loops you will know that all of them require you to run some blocking "loop", "run" or similar function that will actively watch for new events and call your callbacks. -AnyEvent is different, it expects somebody else to run the event loop and -will only block when necessary (usually when told by the user). +AnyEvent is slightly different: it expects somebody else to run the event +loop and will only block when necessary (usually when told by the user). The instrument to do that is called a "condition variable", so called because they represent a condition that must become true. +Now is probably a good time to look at the examples further below. + Condition variables can be created by calling the C<< AnyEvent->condvar >> method, usually without arguments. The only argument pair allowed is - C, which specifies a callback to be called when the condition variable becomes true, with the condition variable as the first argument (but not the results). @@ -488,7 +579,8 @@ in time where multiple outstanding events have been processed. And yet another way to call them is transactions - each condition variable can be used to represent a transaction, which finishes at some point and delivers -a result. +a result. And yet some people know them as "futures" - a promise to +compute/deliver something that you can wait for. Condition variables are very useful to signal that something has finished, for example, if you write a module that does asynchronous http requests, @@ -519,24 +611,24 @@ Example: wait for a timer. - # wait till the result is ready - my $result_ready = AnyEvent->condvar; + # condition: "wait till the timer is fired" + my $timer_fired = AnyEvent->condvar; - # do something such as adding a timer - # or socket watcher the calls $result_ready->send - # when the "result" is ready. + # create the timer - we could wait for, say + # a handle becomign ready, or even an + # AnyEvent::HTTP request to finish, but # in this case, we simply use a timer: my $w = AnyEvent->timer ( after => 1, - cb => sub { $result_ready->send }, + cb => sub { $timer_fired->send }, ); # this "blocks" (while handling events) till the callback - # calls send - $result_ready->recv; + # calls ->send + $timer_fired->recv; -Example: wait for a timer, but take advantage of the fact that -condition variables are also code references. +Example: wait for a timer, but take advantage of the fact that condition +variables are also callable directly. my $done = AnyEvent->condvar; my $delay = AnyEvent->timer (after => 5, cb => $done); @@ -552,7 +644,7 @@ my @info = $couchdb->info->recv; -And this is how you would just ste a callback to be called whenever the +And this is how you would just set a callback to be called whenever the results are available: $couchdb->info->cb (sub { @@ -580,14 +672,9 @@ Any arguments passed to the C call will be returned by all future C<< ->recv >> calls. -Condition variables are overloaded so one can call them directly -(as a code reference). Calling them directly is the same as calling -C. Note, however, that many C-based event loops do not handle -overloading, so as tempting as it may be, passing a condition variable -instead of a callback does not work. Both the pure perl and EV loops -support overloading, however, as well as all functions that use perl to -invoke a callback (as in L and L for -example). +Condition variables are overloaded so one can call them directly (as if +they were a code reference). Calling them directly is the same as calling +C. =item $cv->croak ($error) @@ -595,7 +682,11 @@ C with the given error message/object/scalar. This can be used to signal any errors to the condition variable -user/consumer. +user/consumer. Doing it this way instead of calling C directly +delays the error detetcion, but has the overwhelmign advantage that it +diagnoses the error at the place where the result is expected, and not +deep in some event clalback without connection to the actual code causing +the problem. =item $cv->begin ([group callback]) @@ -607,9 +698,10 @@ Every call to C<< ->begin >> will increment a counter, and every call to C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end ->>, the (last) callback passed to C will be executed. That callback -is I to call C<< ->send >>, but that is not required. If no -callback was set, C will be called without any arguments. +>>, the (last) callback passed to C will be executed, passing the +condvar as first argument. That callback is I to call C<< ->send +>>, but that is not required. If no group callback was set, C will +be called without any arguments. You can think of C<< $cv->send >> giving you an OR condition (one call sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND @@ -646,7 +738,7 @@ my $cv = AnyEvent->condvar; my %result; - $cv->begin (sub { $cv->send (\%result) }); + $cv->begin (sub { shift->send (\%result) }); for my $host (@list_of_hosts) { $cv->begin; @@ -701,25 +793,21 @@ In list context, all parameters passed to C will be returned, in scalar context only the first one will be returned. +Note that doing a blocking wait in a callback is not supported by any +event loop, that is, recursive invocation of a blocking C<< ->recv +>> is not allowed, and the C call will C if such a +condition is detected. This condition can be slightly loosened by using +L, which allows you to do a blocking C<< ->recv >> from +any thread that doesn't run the event loop itself. + Not all event models support a blocking wait - some die in that case (programs might want to do that to stay interactive), so I, but let the +using this from a module, never require a blocking wait>. Instead, let the caller decide whether the call will block or not (for example, by coupling condition variables with some kind of request results and supporting callbacks so the caller knows that getting the result will not block, while still supporting blocking waits if the caller so desires). -Another reason I to C<< ->recv >> in a module is that you cannot -sensibly have two C<< ->recv >>'s in parallel, as that would require -multiple interpreters or coroutines/threads, none of which C -can supply. - -The L module, however, I and I supply coroutines and, in -fact, L replaces AnyEvent's condvars by coroutine-safe -versions and also integrates coroutines into AnyEvent, making blocking -C<< ->recv >> calls perfectly safe as long as they are done from another -coroutine (one that doesn't run the event loop). - You can ensure that C<< -recv >> never blocks by setting a callback and only calling C<< ->recv >> from within that callback (or at a later time). This will work even when the event loop does not support blocking @@ -735,10 +823,10 @@ This is a mutator function that returns the callback set and optionally replaces it before doing so. -The callback will be called when the condition becomes "true", i.e. when -C or C are called, with the only argument being the condition -variable itself. Calling C inside the callback or at any later time -is guaranteed not to block. +The callback will be called when the condition becomes (or already was) +"true", i.e. when C or C are called (or were called), with +the only argument being the condition variable itself. Calling C +inside the callback or at any later time is guaranteed not to block. =back @@ -751,12 +839,11 @@ =item Backends that are autoprobed when no other event loop can be found. EV is the preferred backend when no other event loop seems to be in -use. If EV is not installed, then AnyEvent will try Event, and, failing -that, will fall back to its own pure-perl implementation, which is -available everywhere as it comes with AnyEvent itself. +use. If EV is not installed, then AnyEvent will fall back to its own +pure-perl implementation, which is available everywhere as it comes with +AnyEvent itself. AnyEvent::Impl::EV based on EV (interface to libev, best choice). - AnyEvent::Impl::Event based on Event, very stable, few glitches. AnyEvent::Impl::Perl pure-perl implementation, fast and portable. =item Backends that are transparently being picked up when they are used. @@ -767,10 +854,12 @@ when the main program loads an event module before anything starts to create watchers. Nothing special needs to be done by the main program. + AnyEvent::Impl::Event based on Event, very stable, few glitches. AnyEvent::Impl::Glib based on Glib, slow but very stable. AnyEvent::Impl::Tk based on Tk, very broken. AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. AnyEvent::Impl::POE based on POE, very slow, some limitations. + AnyEvent::Impl::Irssi used when running within irssi. =item Backends with special needs. @@ -854,8 +943,25 @@ avoid autodetecting the event module at load time. If called in scalar or list context, then it creates and returns an object -that automatically removes the callback again when it is destroyed. See -L for a case where this is useful. +that automatically removes the callback again when it is destroyed (or +C when the hook was immediately executed). See L for +a case where this is useful. + +Example: Create a watcher for the IO::AIO module and store it in +C<$WATCHER>. Only do so after the event loop is initialised, though. + + our WATCHER; + + my $guard = AnyEvent::post_detect { + $WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb); + }; + + # the ||= is important in case post_detect immediately runs the block, + # as to not clobber the newly-created watcher. assigning both watcher and + # post_detect guard to the same variable has the advantage of users being + # able to just C if the watcher causes them grief. + + $WATCHER ||= $guard; =item @AnyEvent::post_detect @@ -868,13 +974,26 @@ array will be ignored. Best use C when your application allows -it,as it takes care of these details. +it, as it takes care of these details. This variable is mainly useful for modules that can do something useful when AnyEvent is used and thus want to know when it is initialised, but do not need to even load it by default. This array provides the means to hook into AnyEvent passively, without loading it. +Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used +together, you could put this into Coro (this is the actual code used by +Coro to accomplish this): + + if (defined $AnyEvent::MODEL) { + # AnyEvent already initialised, so load Coro::AnyEvent + require Coro::AnyEvent; + } else { + # AnyEvent not yet initialised, so make sure to load Coro::AnyEvent + # as soon as it is + push @AnyEvent::post_detect, sub { require Coro::AnyEvent }; + } + =back =head1 WHAT TO DO IN A MODULE @@ -940,7 +1059,7 @@ The following is a non-exhaustive list of additional modules that use AnyEvent as a client and can therefore be mixed easily with other AnyEvent modules and other event loops in the same program. Some of the modules -come with AnyEvent, most are available via CPAN. +come with AnyEvent, the others are available via CPAN. =over 4 @@ -965,60 +1084,48 @@ Provides rich asynchronous DNS resolver capabilities. -=item L - -A simple-to-use HTTP library that is capable of making a lot of concurrent -HTTP requests. - -=item L - -Provides a simple web application server framework. - -=item L +=item L, L, L, L, L, L -The fastest ping in the west. +Implement event-based interfaces to the protocols of the same name (for +the curious, IGS is the International Go Server and FCP is the Freenet +Client Protocol). + +=item L + +Here be danger! + +As Pauli would put it, "Not only is it not right, it's not even wrong!" - +there are so many things wrong with AnyEvent::Handle::UDP, most notably +it's use of a stream-based API with a protocol that isn't streamable, that +the only way to improve it is to delete it. + +It features data corruption (but typically only under load) and general +confusion. On top, the author is not only clueless about UDP but also +fact-resistant - some gems of his understanding: "connect doesn't work +with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not +packets", "I don't need to implement proper error checking as UDP doesn't +support error checking" and so on - he doesn't even understand what's +wrong with his module when it is explained to him. =item L -Executes L requests asynchronously in a proxy process. +Executes L requests asynchronously in a proxy process for you, +notifying you in an event-bnased way when the operation is finished. =item L -Truly asynchronous I/O, should be in the toolbox of every event -programmer. AnyEvent::AIO transparently fuses L and AnyEvent -together. - -=item L - -Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses -L and AnyEvent together. - -=item L - -A non-blocking interface to gpsd, a daemon delivering GPS information. - -=item L - -AnyEvent based IRC client module family (replacing the older Net::IRC3). - -=item L +Truly asynchronous (as opposed to non-blocking) I/O, should be in the +toolbox of every event programmer. AnyEvent::AIO transparently fuses +L and AnyEvent together, giving AnyEvent access to event-based +file I/O, and much more. -AnyEvent based XMPP (Jabber protocol) module family (replacing the older -Net::XMPP2>. - -=item L - -A non-blocking interface to the Internet Go Server protocol (used by -L). - -=item L +=item L -AnyEvent-based implementation of the Freenet Client Protocol, birthplace -of AnyEvent. +A simple embedded webserver. -=item L +=item L -High level API for event-based execution flow control. +The fastest ping in the west. =item L @@ -1030,12 +1137,19 @@ package AnyEvent; -no warnings; -use strict qw(vars subs); +# basically a tuned-down version of common::sense +sub common_sense { + # from common:.sense 1.0 + ${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00"; + # use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl) + $^H |= 0x00000600; +} + +BEGIN { AnyEvent::common_sense } -use Carp; +use Carp (); -our $VERSION = 4.81; +our $VERSION = '5.261'; our $MODEL; our $AUTOLOAD; @@ -1043,17 +1157,21 @@ our @REGISTRY; -our $WIN32; +our $VERBOSE; BEGIN { - eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }"; - eval "sub TAINT(){ " . (${^TAINT}*1) . " }"; + require "AnyEvent/constants.pl"; + + eval "sub TAINT (){" . (${^TAINT}*1) . "}"; delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} if ${^TAINT}; + + $VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1; + } -our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; +our $MAX_SIGNAL_LATENCY = 10; our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred @@ -1065,26 +1183,28 @@ } my @models = ( - [EV:: => AnyEvent::Impl::EV::], - [Event:: => AnyEvent::Impl::Event::], - [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], - # everything below here will not be autoprobed + [EV:: => AnyEvent::Impl::EV:: , 1], + [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1], + # everything below here will not (normally) be autoprobed # as the pureperl backend should work everywhere # and is usually faster - [Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers + [Event:: => AnyEvent::Impl::Event::, 1], + [Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy + [Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package [Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles - [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza [Qt:: => AnyEvent::Impl::Qt::], # requires special main program + [POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza [Wx:: => AnyEvent::Impl::POE::], [Prima:: => AnyEvent::Impl::POE::], # IO::Async is just too broken - we would need workarounds for its # byzantine signal and broken child handling, among others. # IO::Async is rather hard to detect, as it doesn't have any # obvious default class. -# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program -# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program -# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program + [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program + [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program + [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program + [AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program ); our %method = map +($_ => 1), @@ -1095,17 +1215,11 @@ sub post_detect(&) { my ($cb) = @_; - if ($MODEL) { - $cb->(); - - 1 - } else { - push @post_detect, $cb; + push @post_detect, $cb; - defined wantarray - ? bless \$cb, "AnyEvent::Util::postdetect" - : () - } + defined wantarray + ? bless \$cb, "AnyEvent::Util::postdetect" + : () } sub AnyEvent::Util::postdetect::DESTROY { @@ -1113,60 +1227,77 @@ } sub detect() { - unless ($MODEL) { - no strict 'refs'; - local $SIG{__DIE__}; + # free some memory + *detect = sub () { $MODEL }; - if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { - my $model = "AnyEvent::Impl::$1"; - if (eval "require $model") { - $MODEL = $model; - warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; - } else { - warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose; + local $!; # for good measure + local $SIG{__DIE__}; + + if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { + my $model = "AnyEvent::Impl::$1"; + if (eval "require $model") { + $MODEL = $model; + warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2; + } else { + warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE; + } + } + + # check for already loaded models + unless ($MODEL) { + for (@REGISTRY, @models) { + my ($package, $model) = @$_; + if (${"$package\::VERSION"} > 0) { + if (eval "require $model") { + $MODEL = $model; + warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2; + last; + } } } - # check for already loaded models unless ($MODEL) { + # try to autoload a model for (@REGISTRY, @models) { - my ($package, $model) = @$_; - if (${"$package\::VERSION"} > 0) { - if (eval "require $model") { - $MODEL = $model; - warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; - last; - } + my ($package, $model, $autoload) = @$_; + if ( + $autoload + and eval "require $package" + and ${"$package\::VERSION"} > 0 + and eval "require $model" + ) { + $MODEL = $model; + warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2; + last; } } - unless ($MODEL) { - # try to load a model + $MODEL + or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; + } + } - for (@REGISTRY, @models) { - my ($package, $model) = @$_; - if (eval "require $package" - and ${"$package\::VERSION"} > 0 - and eval "require $model") { - $MODEL = $model; - warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; - last; - } - } + @models = (); # free probe data - $MODEL - or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n"; - } - } + push @{"$MODEL\::ISA"}, "AnyEvent::Base"; + unshift @ISA, $MODEL; - push @{"$MODEL\::ISA"}, "AnyEvent::Base"; + # now nuke some methods that are overriden by the backend. + # SUPER is not allowed. + for (qw(time signal child idle)) { + undef &{"AnyEvent::Base::$_"} + if defined &{"$MODEL\::$_"}; + } - unshift @ISA, $MODEL; + require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; - require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT}; + (shift @post_detect)->() while @post_detect; - (shift @post_detect)->() while @post_detect; - } + *post_detect = sub(&) { + shift->(); + + undef + }; $MODEL } @@ -1175,9 +1306,9 @@ (my $func = $AUTOLOAD) =~ s/.*://; $method{$func} - or croak "$func: not a valid method for AnyEvent objects"; + or Carp::croak "$func: not a valid AnyEvent class method"; - detect unless $MODEL; + detect; my $class = shift; $class->$func (@_); @@ -1190,9 +1321,9 @@ my ($poll, $fh, $r, $w) = @_; # cygwin requires the fh mode to be matching, unix doesn't - my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">"); + my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&"); - open my $fh2, "$mode&", $fh + open my $fh2, $mode, $fh or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,"; # we assume CLOEXEC is already set by perl in all important cases @@ -1200,94 +1331,274 @@ ($fh2, $rw) } +=head1 SIMPLIFIED AE API + +Starting with version 5.0, AnyEvent officially supports a second, much +simpler, API that is designed to reduce the calling, typing and memory +overhead by using function call syntax and a fixed number of parameters. + +See the L manpage for details. + +=cut + +package AE; + +our $VERSION = $AnyEvent::VERSION; + +# fall back to the main API by default - backends and AnyEvent::Base +# implementations can overwrite these. + +sub io($$$) { + AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2]) +} + +sub timer($$$) { + AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]) +} + +sub signal($$) { + AnyEvent->signal (signal => $_[0], cb => $_[1]) +} + +sub child($$) { + AnyEvent->child (pid => $_[0], cb => $_[1]) +} + +sub idle($) { + AnyEvent->idle (cb => $_[0]) +} + +sub cv(;&) { + AnyEvent->condvar (@_ ? (cb => $_[0]) : ()) +} + +sub now() { + AnyEvent->now +} + +sub now_update() { + AnyEvent->now_update +} + +sub time() { + AnyEvent->time +} + package AnyEvent::Base; # default implementations for many methods -BEGIN { - if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { - *_time = \&Time::HiRes::time; - # if (eval "use POSIX (); (POSIX::times())... - } else { - *_time = sub { time }; # epic fail - } +sub time { + eval q{ # poor man's autoloading {} + # probe for availability of Time::HiRes + if (eval "use Time::HiRes (); Time::HiRes::time (); 1") { + warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8; + *AE::time = \&Time::HiRes::time; + # if (eval "use POSIX (); (POSIX::times())... + } else { + warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE; + *AE::time = sub (){ time }; # epic fail + } + + *time = sub { AE::time }; # different prototypes + }; + die if $@; + + &time } -sub time { _time } -sub now { _time } +*now = \&time; + sub now_update { } # default implementation for ->condvar sub condvar { - bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" + eval q{ # poor man's autoloading {} + *condvar = sub { + bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar" + }; + + *AE::cv = sub (;&) { + bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar" + }; + }; + die if $@; + + &condvar } # default implementation for ->signal -our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); +our $HAVE_ASYNC_INTERRUPT; -sub _signal_exec { - sysread $SIGPIPE_R, my $dummy, 4; +sub _have_async_interrupt() { + $HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} + && eval "use Async::Interrupt 1.02 (); 1") + unless defined $HAVE_ASYNC_INTERRUPT; - while (%SIG_EV) { - for (keys %SIG_EV) { - delete $SIG_EV{$_}; - $_->() for values %{ $SIG_CB{$_} || {} }; - } - } + $HAVE_ASYNC_INTERRUPT } -sub signal { - my (undef, %arg) = @_; +our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO); +our (%SIG_ASY, %SIG_ASY_W); +our ($SIG_COUNT, $SIG_TW); - unless ($SIGPIPE_R) { - require Fcntl; +# install a dummy wakeup watcher to reduce signal catching latency +# used by Impls +sub _sig_add() { + unless ($SIG_COUNT++) { + # try to align timer on a full-second boundary, if possible + my $NOW = AE::now; + + $SIG_TW = AE::timer + $MAX_SIGNAL_LATENCY - ($NOW - int $NOW), + $MAX_SIGNAL_LATENCY, + sub { } # just for the PERL_ASYNC_CHECK + ; + } +} - if (AnyEvent::WIN32) { - require AnyEvent::Util; +sub _sig_del { + undef $SIG_TW + unless --$SIG_COUNT; +} - ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); - AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R; - AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case +our $_sig_name_init; $_sig_name_init = sub { + eval q{ # poor man's autoloading {} + undef $_sig_name_init; + + if (_have_async_interrupt) { + *sig2num = \&Async::Interrupt::sig2num; + *sig2name = \&Async::Interrupt::sig2name; } else { - pipe $SIGPIPE_R, $SIGPIPE_W; - fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R; - fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case - - # not strictly required, as $^F is normally 2, but let's make sure... - fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; - fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC; + require Config; + + my %signame2num; + @signame2num{ split ' ', $Config::Config{sig_name} } + = split ' ', $Config::Config{sig_num}; + + my @signum2name; + @signum2name[values %signame2num] = keys %signame2num; + + *sig2num = sub($) { + $_[0] > 0 ? shift : $signame2num{+shift} + }; + *sig2name = sub ($) { + $_[0] > 0 ? $signum2name[+shift] : shift + }; } + }; + die if $@; +}; - $SIGPIPE_R - or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; +sub sig2num ($) { &$_sig_name_init; &sig2num } +sub sig2name($) { &$_sig_name_init; &sig2name } - $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec); - } +sub signal { + eval q{ # poor man's autoloading {} + # probe for availability of Async::Interrupt + if (_have_async_interrupt) { + warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8; - my $signal = uc $arg{signal} - or Carp::croak "required option 'signal' is missing"; + $SIGPIPE_R = new Async::Interrupt::EventPipe; + $SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec; - $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; - $SIG{$signal} ||= sub { - local $!; - syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; - undef $SIG_EV{$signal}; - }; + } else { + warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8; - bless [$signal, $arg{cb}], "AnyEvent::Base::signal" -} + if (AnyEvent::WIN32) { + require AnyEvent::Util; + + ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe (); + AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R; + AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case + } else { + pipe $SIGPIPE_R, $SIGPIPE_W; + fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R; + fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case + + # not strictly required, as $^F is normally 2, but let's make sure... + fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC; + fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC; + } + + $SIGPIPE_R + or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n"; -sub AnyEvent::Base::signal::DESTROY { - my ($signal, $cb) = @{$_[0]}; + $SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec; + } - delete $SIG_CB{$signal}{$cb}; + *signal = $HAVE_ASYNC_INTERRUPT + ? sub { + my (undef, %arg) = @_; + + # async::interrupt + my $signal = sig2num $arg{signal}; + $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; + + $SIG_ASY{$signal} ||= new Async::Interrupt + cb => sub { undef $SIG_EV{$signal} }, + signal => $signal, + pipe => [$SIGPIPE_R->filenos], + pipe_autodrain => 0, + ; + + bless [$signal, $arg{cb}], "AnyEvent::Base::signal" + } + : sub { + my (undef, %arg) = @_; + + # pure perl + my $signal = sig2name $arg{signal}; + $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; + + $SIG{$signal} ||= sub { + local $!; + syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV; + undef $SIG_EV{$signal}; + }; + + # can't do signal processing without introducing races in pure perl, + # so limit the signal latency. + _sig_add; + + bless [$signal, $arg{cb}], "AnyEvent::Base::signal" + } + ; + + *AnyEvent::Base::signal::DESTROY = sub { + my ($signal, $cb) = @{$_[0]}; + + _sig_del; + + delete $SIG_CB{$signal}{$cb}; + + $HAVE_ASYNC_INTERRUPT + ? delete $SIG_ASY{$signal} + : # delete doesn't work with older perls - they then + # print weird messages, or just unconditionally exit + # instead of getting the default action. + undef $SIG{$signal} + unless keys %{ $SIG_CB{$signal} }; + }; - # delete doesn't work with older perls - they then - # print weird messages, or just unconditionally exit - # instead of getting the default action. - undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} }; + *_signal_exec = sub { + $HAVE_ASYNC_INTERRUPT + ? $SIGPIPE_R->drain + : sysread $SIGPIPE_R, (my $dummy), 9; + + while (%SIG_EV) { + for (keys %SIG_EV) { + delete $SIG_EV{$_}; + $_->() for values %{ $SIG_CB{$_} || {} }; + } + } + }; + }; + die if $@; + + &signal } # default implementation for ->child @@ -1297,75 +1608,101 @@ our $CHLD_DELAY_W; our $WNOHANG; -sub _sigchld { - while (0 < (my $pid = waitpid -1, $WNOHANG)) { - $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), - (values %{ $PID_CB{0} || {} }); - } +# used by many Impl's +sub _emit_childstatus($$) { + my (undef, $rpid, $rstatus) = @_; + + $_->($rpid, $rstatus) + for values %{ $PID_CB{$rpid} || {} }, + values %{ $PID_CB{0} || {} }; } sub child { - my (undef, %arg) = @_; + eval q{ # poor man's autoloading {} + *_sigchld = sub { + my $pid; + + AnyEvent->_emit_childstatus ($pid, $?) + while ($pid = waitpid -1, $WNOHANG) > 0; + }; - defined (my $pid = $arg{pid} + 0) - or Carp::croak "required option 'pid' is missing"; + *child = sub { + my (undef, %arg) = @_; - $PID_CB{$pid}{$arg{cb}} = $arg{cb}; + defined (my $pid = $arg{pid} + 0) + or Carp::croak "required option 'pid' is missing"; - $WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; + $PID_CB{$pid}{$arg{cb}} = $arg{cb}; - unless ($CHLD_W) { - $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); - # child could be a zombie already, so make at least one round - &_sigchld; - } + # WNOHANG is almost cetrainly 1 everywhere + $WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/ + ? 1 + : eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1; + + unless ($CHLD_W) { + $CHLD_W = AE::signal CHLD => \&_sigchld; + # child could be a zombie already, so make at least one round + &_sigchld; + } - bless [$pid, $arg{cb}], "AnyEvent::Base::child" -} + bless [$pid, $arg{cb}], "AnyEvent::Base::child" + }; + + *AnyEvent::Base::child::DESTROY = sub { + my ($pid, $cb) = @{$_[0]}; -sub AnyEvent::Base::child::DESTROY { - my ($pid, $cb) = @{$_[0]}; + delete $PID_CB{$pid}{$cb}; + delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; - delete $PID_CB{$pid}{$cb}; - delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; + undef $CHLD_W unless keys %PID_CB; + }; + }; + die if $@; - undef $CHLD_W unless keys %PID_CB; + &child } # idle emulation is done by simply using a timer, regardless # of whether the process is idle or not, and not letting # the callback use more than 50% of the time. sub idle { - my (undef, %arg) = @_; + eval q{ # poor man's autoloading {} + *idle = sub { + my (undef, %arg) = @_; + + my ($cb, $w, $rcb) = $arg{cb}; + + $rcb = sub { + if ($cb) { + $w = _time; + &$cb; + $w = _time - $w; + + # never use more then 50% of the time for the idle watcher, + # within some limits + $w = 0.0001 if $w < 0.0001; + $w = 5 if $w > 5; + + $w = AE::timer $w, 0, $rcb; + } else { + # clean up... + undef $w; + undef $rcb; + } + }; - my ($cb, $w, $rcb) = $arg{cb}; + $w = AE::timer 0.05, 0, $rcb; - $rcb = sub { - if ($cb) { - $w = _time; - &$cb; - $w = _time - $w; - - # never use more then 50% of the time for the idle watcher, - # within some limits - $w = 0.0001 if $w < 0.0001; - $w = 5 if $w > 5; + bless \\$cb, "AnyEvent::Base::idle" + }; - $w = AnyEvent->timer (after => $w, cb => $rcb); - } else { - # clean up... - undef $w; - undef $rcb; - } + *AnyEvent::Base::idle::DESTROY = sub { + undef $${$_[0]}; + }; }; + die if $@; - $w = AnyEvent->timer (after => 0.05, cb => $rcb); - - bless \\$cb, "AnyEvent::Base::idle" -} - -sub AnyEvent::Base::idle::DESTROY { - undef $${$_[0]}; + &idle } package AnyEvent::CondVar; @@ -1374,9 +1711,17 @@ package AnyEvent::CondVar::Base; -use overload - '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, - fallback => 1; +#use overload +# '&{}' => sub { my $self = shift; sub { $self->send (@_) } }, +# fallback => 1; + +# save 300+ kilobytes by dirtily hardcoding overloading +${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching. +*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod." +*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{} +${'AnyEvent::CondVar::Base::()'} = 1; # fallback + +our $WAITING; sub _send { # nop @@ -1399,6 +1744,11 @@ } sub _wait { + $WAITING + and !$_[0]{_ae_sent} + and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected"; + + local $WAITING = 1; AnyEvent->one_event while !$_[0]{_ae_sent}; } @@ -1410,8 +1760,14 @@ } sub cb { - $_[0]{_ae_cb} = $_[1] if @_ > 1; - $_[0]{_ae_cb} + my $cv = shift; + + @_ + and $cv->{_ae_cb} = shift + and $cv->{_ae_sent} + and (delete $cv->{_ae_cb})->($cv); + + $cv->{_ae_cb} } sub begin { @@ -1470,6 +1826,9 @@ When set to C<2> or higher, cause AnyEvent to report to STDERR which event model it chooses. +When set to C<8> or higher, then AnyEvent will report extra information on +which optional modules it loads and how it implements certain features. + =item C AnyEvent does not do much argument checking by default, as thorough @@ -1480,9 +1839,10 @@ In other words, enables "strict" mode. -Unlike C, it is definitely recommended to keep it off in -production. Keeping C in your environment while -developing programs can be very useful, however. +Unlike C (or it's modern cousin, C<< use L +>>, it is definitely recommended to keep it off in production. Keeping +C in your environment while developing programs +can be very useful, however. =item C @@ -1555,6 +1915,11 @@ variables exist, they will be used to specify CA certificate locations instead of a system-dependent default. +=item C and C + +When these are set to C<1>, then the respective modules are not +loaded. Mostly good for testing AnyEvent itself. + =back =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE @@ -1621,16 +1986,9 @@ }, ); - my $time_watcher; # can only be used once - - sub new_timer { - $timer = AnyEvent->timer (after => 1, cb => sub { - warn "timeout\n"; # print 'timeout' about every second - &new_timer; # and restart the time - }); - } - - new_timer; # create first timer + my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub { + warn "timeout\n"; # print 'timeout' at most every second + }); $cv->recv; # wait until user enters /^q/i @@ -1713,7 +2071,7 @@ that occurred during request processing. The C method detects whether an exception as thrown (it is stored inside the $txn object) and just throws the exception, which means connection errors and other -problems get reported tot he code that tries to use the result, not in a +problems get reported to the code that tries to use the result, not in a random callback. All of this enables the following usage styles: @@ -1771,7 +2129,8 @@ which it is), lets them fire exactly once and destroys them again. Source code for this benchmark is found as F in the AnyEvent -distribution. +distribution. It uses the L interface, which makes a real difference +for the EV and Perl backends only. =head3 Explanation of the columns @@ -1802,18 +2161,18 @@ =head3 Results name watchers bytes create invoke destroy comment - EV/EV 400000 224 0.47 0.35 0.27 EV native interface - EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers - CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal - Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation - Event/Event 16000 517 32.20 31.80 0.81 Event native interface - Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers - IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll - IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll - Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour - Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers - POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event - POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select + EV/EV 100000 223 0.47 0.43 0.27 EV native interface + EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers + Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal + Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation + Event/Event 16000 516 31.16 31.84 0.82 Event native interface + Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers + IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll + IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll + Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour + Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers + POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event + POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select =head3 Discussion @@ -1835,9 +2194,10 @@ cycles with POE. C is the sole leader regarding speed and memory use, which are both -maximal/minimal, respectively. Even when going through AnyEvent, it uses -far less memory than any other event loop and is still faster than Event -natively. +maximal/minimal, respectively. When using the L API there is zero +overhead (when going through the AnyEvent API create is about 5-6 times +slower, with other times being equal, so still uses far less memory than +any other event loop and is still faster than Event natively). The pure perl implementation is hit in a few sweet spots (both the constant timeout and the use of a single fd hit optimisations in the perl @@ -1921,7 +2281,8 @@ connections, most of which are idle at any one point in time. Source code for this benchmark is found as F in the AnyEvent -distribution. +distribution. It uses the L interface, which makes a real difference +for the EV and Perl backends only. =head3 Explanation of the columns @@ -1939,13 +2300,13 @@ =head3 Results name sockets create request - EV 20000 69.01 11.16 - Perl 20000 73.32 35.87 - IOAsync 20000 157.00 98.14 epoll - IOAsync 20000 159.31 616.06 poll - Event 20000 212.62 257.32 - Glib 20000 651.16 1896.30 - POE 20000 349.67 12317.24 uses POE::Loop::Event + EV 20000 62.66 7.99 + Perl 20000 68.32 32.64 + IOAsync 20000 174.06 101.15 epoll + IOAsync 20000 174.67 610.84 poll + Event 20000 202.69 242.91 + Glib 20000 557.01 1689.52 + POE 20000 341.54 12086.32 uses POE::Loop::Event =head3 Discussion @@ -2081,13 +2442,13 @@ backend easily beats IO::Lambda and POE. And even the 100% non-blocking version written using the high-level (and -slow :) L abstraction beats both POE and IO::Lambda by a -large margin, even though it does all of DNS, tcp-connect and socket I/O -in a non-blocking way. +slow :) L abstraction beats both POE and IO::Lambda +higher level ("unoptimised") abstractions by a large margin, even though +it does all of DNS, tcp-connect and socket I/O in a non-blocking way. The two AnyEvent benchmarks programs can be found as F and F in the AnyEvent distribution, the remaining benchmarks are -part of the IO::lambda distribution and were used without any changes. +part of the IO::Lambda distribution and were used without any changes. =head1 SIGNALS @@ -2102,8 +2463,8 @@ emulation for event loops that do not support them natively. Also, some event loops install a similar handler. -If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will -reset it to default, to avoid losing child exit statuses. +Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then +AnyEvent will reset it to default, to avoid losing child exit statuses. =item SIGPIPE @@ -2131,14 +2492,111 @@ $SIG{PIPE} = sub { } unless defined $SIG{PIPE}; +=head1 RECOMMENDED/OPTIONAL MODULES + +One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and +it's built-in modules) are required to use it. + +That does not mean that AnyEvent won't take advantage of some additional +modules if they are installed. + +This section explains which additional modules will be used, and how they +affect AnyEvent's operation. + +=over 4 + +=item L + +This slightly arcane module is used to implement fast signal handling: To +my knowledge, there is no way to do completely race-free and quick +signal handling in pure perl. To ensure that signals still get +delivered, AnyEvent will start an interval timer to wake up perl (and +catch the signals) with some delay (default is 10 seconds, look for +C<$AnyEvent::MAX_SIGNAL_LATENCY>). + +If this module is available, then it will be used to implement signal +catching, which means that signals will not be delayed, and the event loop +will not be interrupted regularly, which is more efficient (and good for +battery life on laptops). + +This affects not just the pure-perl event loop, but also other event loops +that have no signal handling on their own (e.g. Glib, Tk, Qt). + +Some event loops (POE, Event, Event::Lib) offer signal watchers natively, +and either employ their own workarounds (POE) or use AnyEvent's workaround +(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L +does nothing for those backends. + +=item L + +This module isn't really "optional", as it is simply one of the backend +event loops that AnyEvent can use. However, it is simply the best event +loop available in terms of features, speed and stability: It supports +the AnyEvent API optimally, implements all the watcher types in XS, does +automatic timer adjustments even when no monotonic clock is available, +can take avdantage of advanced kernel interfaces such as C and +C, and is the fastest backend I. You can even embed +L/L in it (or vice versa, see L and L). + +If you only use backends that rely on another event loop (e.g. C), +then this module will do nothing for you. + +=item L + +The guard module, when used, will be used to implement +C. This speeds up guards considerably (and uses a +lot less memory), but otherwise doesn't affect guard operation much. It is +purely used for performance. + +=item L and L + +One of these modules is required when you want to read or write JSON data +via L. L is also written in pure-perl, but can take +advantage of the ultra-high-speed L module when it is installed. + +=item L + +Implementing TLS/SSL in Perl is certainly interesting, but not very +worthwhile: If this module is installed, then L (with +the help of L), gains the ability to do TLS/SSL. + +=item L + +This module is part of perl since release 5.008. It will be used when the +chosen event library does not come with a timing source on it's own. The +pure-perl event loop (L) will additionally use it to +try to use a monotonic clock for timing stability. + +=back + + =head1 FORK Most event libraries are not fork-safe. The ones who are usually are -because they rely on inefficient but fork-safe C or C calls +- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll +are usually badly thought-out hacks that are incompatible with fork in +one way or another. Only L is fully fork-aware and ensures that you +continue event-processing in both parent and child (or both, if you know +what you are doing). + +This means that, in general, you cannot fork and do event processing in +the child if the event library was initialised before the fork (which +usually happens when the first AnyEvent watcher is created, or the library +is loaded). If you have to fork, you must either do so I creating your first -watcher OR you must not use AnyEvent at all in the child. +watcher OR you must not use AnyEvent at all in the child OR you must do +something completely out of the scope of AnyEvent. + +The problem of doing event processing in the parent I the child +is much more complicated: even for backends that I fork-aware or +fork-safe, their behaviour is not usually what you want: fork clones all +watchers, that means all timers, I/O watchers etc. are active in both +parent and child, which is almost never what you want. USing C +to start worker children from some kind of manage rprocess is usually +preferred, because it is much easier and cleaner, at the expense of having +to have another binary. =head1 SECURITY CONSIDERATIONS @@ -2186,7 +2644,7 @@ Implementations: L, L, L, L, L, L, L, -L, L. +L, L, L. Non-blocking file handles, sockets, TCP clients and servers: L, L, L.