--- AnyEvent/lib/AnyEvent.pm 2008/05/10 20:30:35 1.113 +++ AnyEvent/lib/AnyEvent.pm 2008/05/24 02:50:45 1.128 @@ -1,4 +1,4 @@ -=head1 NAME +=head1 => NAME AnyEvent - provide framework for multiple event loops @@ -17,8 +17,8 @@ }); my $w = AnyEvent->condvar; # stores whether a condition was flagged - $w->wait; # enters "main loop" till $condvar gets ->send - $w->send; # wake up current and all future wait's + $w->send; # wake up current and all future recv's + $w->recv; # enters "main loop" till $condvar gets ->send =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) @@ -59,7 +59,7 @@ In addition to being free of having to use I, AnyEvent also is free of bloat and policy: with POE or similar -modules, you get an enourmous amount of code and strict rules you have to +modules, you get an enormous amount of code and strict rules you have to follow. AnyEvent, on the other hand, is lean and up to the point, by only offering the functionality that is necessary, in as thin as a wrapper as technically possible. @@ -110,7 +110,7 @@ AnyEvent has the central concept of a I, which is an object that stores relevant data for each kind of event you are waiting for, such as -the callback to call, the filehandle to watch, etc. +the callback to call, the file handle to watch, etc. These watchers are normal Perl objects with normal Perl lifetime. After creating a watcher it will immediately "watch" for events and invoke the @@ -281,8 +281,6 @@ my $done = AnyEvent->condvar; - AnyEvent::detect; # force event module to be initialised - my $pid = fork or exit 5; my $w = AnyEvent->child ( @@ -295,7 +293,7 @@ ); # do something else, then wait for process exit - $done->wait; + $done->recv; =head2 CONDITION VARIABLES @@ -328,15 +326,15 @@ for example, if you write a module that does asynchronous http requests, then a condition variable would be the ideal candidate to signal the availability of results. The user can either act when the callback is -called or can synchronously C<< ->wait >> for the results. +called or can synchronously C<< ->recv >> for the results. You can also use them to simulate traditional event loops - for example, you can block your main program until an event occurs - for example, you -could C<< ->wait >> in your main program until the user clicks the Quit +could C<< ->recv >> in your main program until the user clicks the Quit button of your app, which would C<< ->send >> the "quit" event. Note that condition variables recurse into the event loop - if you have -two pieces of code that call C<< ->wait >> in a round-robbin fashion, you +two pieces of code that call C<< ->recv >> in a round-robbin fashion, you lose. Therefore, condition variables are good to export to your caller, but you should avoid making a blocking wait yourself, at least in callbacks, as this asks for trouble. @@ -367,7 +365,7 @@ # this "blocks" (while handling events) till the callback # calls send - $result_ready->wait; + $result_ready->recv; =head3 METHODS FOR PRODUCERS @@ -380,19 +378,19 @@ =item $cv->send (...) -Flag the condition as ready - a running C<< ->wait >> and all further -calls to C will (eventually) return after this method has been +Flag the condition as ready - a running C<< ->recv >> and all further +calls to C will (eventually) return after this method has been called. If nobody is waiting the send will be remembered. If a callback has been set on the condition variable, it is called immediately from within send. Any arguments passed to the C call will be returned by all -future C<< ->wait >> calls. +future C<< ->recv >> calls. =item $cv->croak ($error) -Similar to send, but causes all call's wait C<< ->wait >> to invoke +Similar to send, but causes all call's to C<< ->recv >> to invoke C with the given error message/object/scalar. This can be used to signal any errors to the condition variable @@ -402,6 +400,8 @@ =item $cv->end +These two methods are EXPERIMENTAL and MIGHT CHANGE. + These two methods can be used to combine many transactions/events into one. For example, a function that pings many hosts in parallel might want to use a condition variable for the whole process. @@ -456,7 +456,7 @@ =over 4 -=item $cv->wait +=item $cv->recv Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak >> methods have been called on c<$cv>, while servicing other watchers @@ -479,19 +479,19 @@ callbacks so the caller knows that getting the result will not block, while still suppporting blocking waits if the caller so desires). -Another reason I to C<< ->wait >> in a module is that you cannot -sensibly have two C<< ->wait >>'s in parallel, as that would require +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<< ->wait >> calls perfectly safe as long as they are done from another +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<< -wait >> never blocks by setting a callback and -only calling C<< ->wait >> from within that callback (or at a later +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 waits otherwise. @@ -506,7 +506,7 @@ replaces it before doing so. The callback will be called when the condition becomes "true", i.e. when -C or C are called. Calling C inside the callback +C or C are called. Calling C inside the callback or at any later time is guaranteed not to block. =back @@ -584,14 +584,14 @@ by calling AnyEvent in your module body you force the user of your module to load the event module first. -Never call C<< ->wait >> on a condition variable unless you I that +Never call C<< ->recv >> on a condition variable unless you I that the C<< ->send >> method has been called on it already. This is because it will stall the whole program, and the whole point of using events is to stay interactive. -It is fine, however, to call C<< ->wait >> when the user of your module +It is fine, however, to call C<< ->recv >> when the user of your module requests it (i.e. if you create a http request object ad have a method -called C that returns the results, it should call C<< ->wait >> +called C that returns the results, it should call C<< ->recv >> freely, as the user of your module knows what she is doing. always). =head1 WHAT TO DO IN THE MAIN PROGRAM @@ -633,14 +633,19 @@ Provide read and write buffers and manages watchers for reads and writes. +=item L + +Provides various utility functions for (internet protocol) sockets, +addresses and name resolution. Also functions to create non-blocking tcp +connections or tcp servers, with IPv6 and SRV record support and more. + =item L Provides a simple web application server framework. =item L -Provides asynchronous DNS resolver capabilities, beyond what -L offers. +Provides rich asynchronous DNS resolver capabilities. =item L @@ -693,7 +698,7 @@ use Carp; -our $VERSION = '3.4'; +our $VERSION = '3.6'; our $MODEL; our $AUTOLOAD; @@ -703,6 +708,14 @@ our @REGISTRY; +our %PROTOCOL; # (ipv4|ipv6) => (1|2) + +{ + my $idx; + $PROTOCOL{$_} = ++$idx + for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6"; +} + my @models = ( [EV:: => AnyEvent::Impl::EV::], [Event:: => AnyEvent::Impl::Event::], @@ -732,12 +745,12 @@ push @post_detect, $cb; defined wantarray - ? bless \$cb, "AnyEvent::Util::Guard" + ? bless \$cb, "AnyEvent::Util::PostDetect" : () } } -sub AnyEvent::Util::Guard::DESTROY { +sub AnyEvent::Util::PostDetect::DESTROY { @post_detect = grep $_ != ${$_[0]}, @post_detect; } @@ -810,18 +823,10 @@ package AnyEvent::Base; -# default implementation for ->condvar, ->wait, ->broadcast +# default implementation for ->condvar sub condvar { - bless \my $flag, "AnyEvent::Base::CondVar" -} - -sub AnyEvent::Base::CondVar::broadcast { - ${$_[0]}++; -} - -sub AnyEvent::Base::CondVar::wait { - AnyEvent->one_event while !${$_[0]}; + bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar:: } # default implementation for ->signal @@ -905,6 +910,62 @@ undef $CHLD_W unless keys %PID_CB; } +package AnyEvent::CondVar; + +our @ISA = AnyEvent::CondVar::Base::; + +package AnyEvent::CondVar::Base; + +sub _send { + # nop +} + +sub send { + my $cv = shift; + $cv->{_ae_sent} = [@_]; + (delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb}; + $cv->_send; +} + +sub croak { + $_[0]{_ae_croak} = $_[1]; + $_[0]->send; +} + +sub ready { + $_[0]{_ae_sent} +} + +sub _wait { + AnyEvent->one_event while !$_[0]{_ae_sent}; +} + +sub recv { + $_[0]->_wait; + + Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak}; + wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0] +} + +sub cb { + $_[0]{_ae_cb} = $_[1] if @_ > 1; + $_[0]{_ae_cb} +} + +sub begin { + ++$_[0]{_ae_counter}; + $_[0]{_ae_end_cb} = $_[1] if @_ > 1; +} + +sub end { + return if --$_[0]{_ae_counter}; + &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } }; +} + +# undocumented/compatibility with pre-3.4 +*broadcast = \&send; +*wait = \&_wait; + =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE This is an advanced topic that you do not normally need to use AnyEvent in @@ -970,11 +1031,11 @@ =item C This can be used to specify the event model to be used by AnyEvent, before -autodetection and -probing kicks in. It must be a string consisting +auto detection and -probing kicks in. It must be a string consisting entirely of ASCII letters. The string C gets prepended and the resulting module name is loaded and if the load was successful, used as event model. If it fails to load AnyEvent will proceed with -autodetection and -probing. +auto detection and -probing. This functionality might change in future versions. @@ -983,6 +1044,37 @@ PERL_ANYEVENT_MODEL=Perl perl ... +=item C + +Used by both L and L to determine preferences +for IPv4 or IPv6. The default is unspecified (and might change, or be the result +of auto probing). + +Must be set to a comma-separated list of protocols or address families, +current supported: C and C. Only protocols mentioned will be +used, and preference will be given to protocols mentioned earlier in the +list. + +This variable can effectively be used for denial-of-service attacks +against local programs (e.g. when setuid), although the impact is likely +small, as the program has to handle connection errors already- + +Examples: C - prefer IPv4 over IPv6, +but support both and try to use both. C +- only support IPv4, never try to resolve or contact IPv6 +addresses. C support either IPv4 or +IPv6, but prefer IPv6 over IPv4. + +=item C + +Used by L to decide whether to use the EDNS0 extension +for DNS. This extension is generally useful to reduce DNS traffic, but +some (broken) firewalls drop such DNS packets, which is why it is off by +default. + +Setting this variable to C<1> will cause L to announce +EDNS0 in its DNS requests. + =back =head1 EXAMPLE PROGRAM @@ -1002,7 +1094,7 @@ warn "io event <$_[0]>\n"; # will always output chomp (my $input = ); # read a line warn "read: $input\n"; # output what has been read - $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i + $cv->send if $input =~ /^q/i; # quit program if /^q/i }, ); @@ -1017,7 +1109,7 @@ new_timer; # create first timer - $cv->wait; # wait until user enters /^q/i + $cv->recv; # wait until user enters /^q/i =head1 REAL-WORLD EXAMPLE @@ -1077,13 +1169,13 @@ $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); Again, C waits till all data has arrived, and then stores the -result and signals any possible waiters that the request ahs finished: +result and signals any possible waiters that the request has finished: sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; if (end-of-file or data complete) { $txn->{result} = $txn->{buf}; - $txn->{finished}->broadcast; + $txn->{finished}->send; $txb->{cb}->($txn) of $txn->{cb}; # also call callback } @@ -1091,11 +1183,11 @@ request was already finished, it doesn't wait, of course, and returns the data: - $txn->{finished}->wait; + $txn->{finished}->recv; return $txn->{result}; The actual code goes further and collects all errors (Cs, exceptions) -that occured during request processing. The C method detects +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 @@ -1136,10 +1228,10 @@ $fcp->txn_client_get ($url)->cb (sub { ... - $quit->broadcast; + $quit->send; }); - $quit->wait; + $quit->recv; =head1 BENCHMARKS @@ -1151,7 +1243,7 @@ =head2 BENCHMARKING ANYEVENT OVERHEAD Here is a benchmark of various supported event models used natively and -through anyevent. The benchmark creates a lot of timers (with a zero +through AnyEvent. The benchmark creates a lot of timers (with a zero timeout) and I/O watchers (watching STDOUT, a pty, to become writable, which it is), lets them fire exactly once and destroys them again. @@ -1178,7 +1270,7 @@ I is the time, in microseconds, used to invoke a simple callback. The callback simply counts down a Perl variable and after it was -invoked "watcher" times, it would C<< ->broadcast >> a condvar once to +invoked "watcher" times, it would C<< ->send >> a condvar once to signal the end of this phase. I is the time, in microseconds, that it takes to destroy a single @@ -1284,19 +1376,19 @@ =head2 BENCHMARKING THE LARGE SERVER CASE -This benchmark atcually benchmarks the event loop itself. It works by -creating a number of "servers": each server consists of a socketpair, a +This benchmark actually benchmarks the event loop itself. It works by +creating a number of "servers": each server consists of a socket pair, a timeout watcher that gets reset on activity (but never fires), and an I/O watcher waiting for input on one side of the socket. Each time the socket watcher reads a byte it will write that byte to a random other "server". The effect is that there will be a lot of I/O watchers, only part of which are active at any one point (so there is a constant number of active -fds for each loop iterstaion, but which fds these are is random). The +fds for each loop iteration, but which fds these are is random). The timeout is reset each time something is read because that reflects how most timeouts work (and puts extra pressure on the event loops). -In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 +In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100 (1%) are active. This mirrors the activity of large servers with many connections, most of which are idle at any one point in time. @@ -1308,7 +1400,7 @@ I is the number of sockets, and twice the number of "servers" (as each server has a read and write socket end). -I is the time it takes to create a socketpair (which is +I is the time it takes to create a socket pair (which is nontrivial) and two watchers: an I/O watcher and a timeout watcher. I, the most important value, is the time it takes to handle a @@ -1441,6 +1533,8 @@ =head1 SEE ALSO +Utility functions: L. + Event modules: L, L, L, L, L, L, L, L, L, L. @@ -1449,9 +1543,14 @@ L, L, L. +Non-blocking file handles, sockets, TCP clients and +servers: L, L. + +Asynchronous DNS: L. + Coroutine support: L, L, L, L, -Nontrivial usage examples: L, L. +Nontrivial usage examples: L, L, L. =head1 AUTHOR