--- AnyEvent/lib/AnyEvent.pm 2008/05/10 01:04:42 1.112 +++ AnyEvent/lib/AnyEvent.pm 2008/05/10 22:30:28 1.116 @@ -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 @@ -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 @@ -633,10 +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. @@ -671,19 +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 @@ -813,18 +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 @@ -908,6 +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