--- AnyEvent/lib/AnyEvent.pm 2008/05/10 00:57:31 1.110 +++ AnyEvent/lib/AnyEvent.pm 2008/05/23 20:41:25 1.123 @@ -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) @@ -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 @@ -551,15 +551,16 @@ have created an AnyEvent watcher anyway, that is, as late as possible at runtime. -=item $guard = AnyEvent::on_detect { BLOCK } +=item $guard = AnyEvent::post_detect { BLOCK } Arranges for the code block to be executed as soon as the event model is autodetected (or immediately if this has already happened). If called in scalar or list context, then it creates and returns an object -that automatically removes the callback again when it is destroyed. +that automatically removes the callback again when it is destroyed. See +L for a case where this is useful. -=item @AnyEvent::on_detect +=item @AnyEvent::post_detect If there are any code references in this array (you can C to it before or after loading AnyEvent), then they will called directly after @@ -569,7 +570,7 @@ if it contains a true value then the event loop has already been detected, and the array will be ignored. -Best use C instead. +Best use C instead. =back @@ -583,14 +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 @@ -632,10 +633,6 @@ Provide read and write buffers and manages watchers for reads and writes. -=item L - -Provides a means to do non-blocking connects, accepts etc. - =item L Provides a simple web application server framework. @@ -670,19 +667,20 @@ Has special support for AnyEvent via L. -=item L +=item L, L -The lambda approach to I/O - don't ask, look there. Can use AnyEvent. +Truly asynchronous I/O, should be in the toolbox of every event +programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent +together. -=item L +=item L, L -Truly asynchronous I/O, should be in the toolbox of every event -programmer. Can be trivially made to use AnyEvent. +Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses +IO::AIO and AnyEvent together. -=item L +=item L -Truly asynchronous Berkeley DB access. Can be trivially made to use -AnyEvent. +The lambda approach to I/O - don't ask, look there. Can use AnyEvent. =back @@ -695,7 +693,7 @@ use Carp; -our $VERSION = '3.4'; +our $VERSION = '3.6'; our $MODEL; our $AUTOLOAD; @@ -721,9 +719,9 @@ our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY); -our @on_detect; +our @post_detect; -sub on_detect(&) { +sub post_detect(&) { my ($cb) = @_; if ($MODEL) { @@ -731,16 +729,16 @@ 1 } else { - push @on_detect, $cb; + push @post_detect, $cb; defined wantarray - ? bless \$cb, "AnyEvent::Util::Guard" + ? bless \$cb, "AnyEvent::Util::PostDetect" : () } } -sub AnyEvent::Util::Guard::DESTROY { - @on_detect = grep $_ != ${$_[0]}, @on_detect; +sub AnyEvent::Util::PostDetect::DESTROY { + @post_detect = grep $_ != ${$_[0]}, @post_detect; } sub detect() { @@ -792,7 +790,7 @@ unshift @ISA, $MODEL; push @{"$MODEL\::ISA"}, "AnyEvent::Base"; - (shift @on_detect)->() while @on_detect; + (shift @post_detect)->() while @post_detect; } $MODEL @@ -812,18 +810,10 @@ 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 {}, AnyEvent::CondVar:: } # default implementation for ->signal @@ -907,6 +897,62 @@ 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} } if $_[0]{_ae_end_cb}; +} + +# undocumented/compatibility with pre-3.4 +*broadcast = \&send; +*wait = \&_wait; + =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE This is an advanced topic that you do not normally need to use AnyEvent in @@ -1004,7 +1050,7 @@ warn "io event <$_[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 }, ); @@ -1019,7 +1065,7 @@ 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 @@ -1085,7 +1131,7 @@ 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 } @@ -1093,7 +1139,7 @@ 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) @@ -1138,10 +1184,10 @@ $fcp->txn_client_get ($url)->cb (sub { ... - $quit->broadcast; + $quit->send; }); - $quit->wait; + $quit->recv; =head1 BENCHMARKS @@ -1180,7 +1226,7 @@ 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 @@ -1451,6 +1497,8 @@ L, L, L. +Asynchronous DNS: L. + Coroutine support: L, L, L, L, Nontrivial usage examples: L, L.