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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.32 by root, Sat Nov 3 09:29:51 2007 UTC vs.
Revision 1.51 by root, Wed Apr 16 15:10:10 2008 UTC

 =head1 NAME
 AnyEvent - provide framework for multiple event loops
-Event, Coro, Glib, Tk, Perl - various supported event loops
+EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl - various supported event loops
 =head1 SYNOPSIS
    use AnyEvent;
    });
    my $w = AnyEvent->condvar; # stores wether a condition was flagged
    $w->wait; # enters "main loop" till $condvar gets ->broadcast
    $w->broadcast; # wake up current and all future wait's
+=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
+Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
+nowadays. So what is different about AnyEvent?
+Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
+policy> and AnyEvent is I<small and efficient>.
+First and foremost, I<AnyEvent is not an event model> itself, it only
+interfaces to whatever event model the main program happens to use in a
+pragmatic way. For event models and certain classes of immortals alike,
+the statement "there can only be one" is a bitter reality, and AnyEvent
+helps hiding the differences.
+The goal of AnyEvent is to offer module authors the ability to do event
+programming (waiting for I/O or timer events) without subscribing to a
+religion, a way of living, and most importantly: without forcing your
+module users into the same thing by forcing them to use the same event
+model you use.
+For modules like POE or IO::Async (which is actually doing all I/O
+I<synchronously>...), using them in your module is like joining a
+cult: After you joined, you are dependent on them and you cannot use
+anything else, as it is simply incompatible to everything that isn't
+itself.
+AnyEvent + POE works fine. AnyEvent + Glib works fine. AnyEvent + Tk
+works fine etc. etc. but none of these work together with the rest: POE
++ IO::Async? no go. Tk + Event? no go. If your module uses one of
+those, every user of your module has to use it, too. If your module
+uses AnyEvent, it works transparently with all event models it supports
+(including stuff like POE and IO::Async).
+In addition of being free of having to use I<the one and only true event
+model>, 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 follow. AnyEvent, on the other hand, is lean and to the point by only
+offering the functionality that is useful, in as thin as a wrapper as
+technically possible.
+Of course, if you want lots of policy (this can arguably be somewhat
+useful) and you want to force your users to use the one and only event
+model, you should I<not> use this module.
 =head1 DESCRIPTION
 L<AnyEvent> provides an identical interface to multiple event loops. This
 allows module authors to utilise an event loop without forcing module
 The interface itself is vaguely similar but not identical to the Event
 module.
 On the first call of any method, the module tries to detect the currently
 loaded event loop by probing wether any of the following modules is
-loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is
+loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, L<Event>, L<Glib>, L<Tk>. The
-used. If none is found, the module tries to load these modules in the
+first one found is used. If none are found, the module tries to load these
-order given. The first one that could be successfully loaded will be
+modules in the order given. The first one that could be successfully
-used. If still none could be found, AnyEvent will fall back to a pure-perl
+loaded will be used. If still none could be found, AnyEvent will fall back
-event loop, which is also not very efficient.
+to a pure-perl event loop, which is also not very efficient.
 Because AnyEvent first checks for modules that are already loaded, loading
 an Event model explicitly before first using AnyEvent will likely make
 that model the default. For example:
 You can create I/O watcher by calling the C<< AnyEvent->io >> method with
 the following mandatory arguments:
 C<fh> the Perl I<filehandle> (not filedescriptor) to watch for
 events. C<poll> must be a string that is either C<r> or C<w>, that creates
-a watcher waiting for "r"eadable or "w"ritable events. C<cb> teh callback
+a watcher waiting for "r"eadable or "w"ritable events. C<cb> the callback
 to invoke everytime the filehandle becomes ready.
-Only one io watcher per C<fh> and C<poll> combination is allowed (i.e. on
-a socket you can have one r + one w, not any more (limitation comes from
-Tk - if you are sure you are not using Tk this limitation is gone).
 Filehandles will be kept alive, so as long as the watcher exists, the
 filehandle exists, too.
 Example:
    my $w = AnyEvent->timer (after => 7.7, cb => sub {
       warn "timeout\n";
    });
    # to cancel the timer:
-   undef $w
+   undef $w;
 =head2 CONDITION WATCHERS
 Condition watchers can be created by calling the C<< AnyEvent->condvar >>
 method without any arguments.
 A condition watcher watches for a condition - precisely that the C<<
 ->broadcast >> method has been called.
+Note that condition watchers recurse into the event loop - if you have
+two watchers that call C<< ->wait >> in a round-robbin fashion, you
+lose. Therefore, condition watchers are good to export to your caller, but
+you should avoid making a blocking wait, at least in callbacks, as this
+usually asks for trouble.
 The watcher has only two methods:
 =over 4
 =item $cv->wait
 Wait (blocking if necessary) until the C<< ->broadcast >> method has been
 called on c<$cv>, while servicing other watchers normally.
-Not all event models support a blocking wait - some die in that case, so
-if you are using this from a module, never require a blocking wait, but
-let the caller decide wether 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 suppporting blockign waits if the caller so desires).
 You can only wait once on a condition - additional calls will return
 immediately.
+Not all event models support a blocking wait - some die in that case
+(programs might want to do that so they stay interactive), so I<if you
+are using this from a module, never require a blocking wait>, but let the
+caller decide wether 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 suppporting blocking waits if the caller so desires).
+Another reason I<never> to C<< ->wait >> in a module is that you cannot
+sensibly have two C<< ->wait >>'s in parallel, as that would require
+multiple interpreters or coroutines/threads, none of which C<AnyEvent>
+can supply (the coroutine-aware backends C<Coro::EV> and C<Coro::Event>
+explicitly support concurrent C<< ->wait >>'s from different coroutines,
+however).
 =item $cv->broadcast
 Flag the condition as ready - a running C<< ->wait >> and all further
 calls to C<wait> will return after this method has been called. If nobody
 C<AnyEvent::Impl:xxx> modules, but can be any other class in the case
 AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).
 The known classes so far are:
-   EV::AnyEvent              based on EV (an interface to libev, best choice)
+   AnyEvent::Impl::CoroEV    based on Coro::EV, best choice.
-   AnyEvent::Impl::Coro      based on Coro::Event, second best choice.
+   AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
+   AnyEvent::Impl::EV        based on EV (an interface to libev, also best choice).
    AnyEvent::Impl::Event     based on Event, also second best choice :)
-   AnyEvent::Impl::Glib      based on Glib, second-best choice.
+   AnyEvent::Impl::Glib      based on Glib, third-best choice.
    AnyEvent::Impl::Tk        based on Tk, very bad choice.
-   AnyEvent::Impl::Perl      pure-perl implementation, inefficient.
+   AnyEvent::Impl::Perl      pure-perl implementation, inefficient but portable.
 =item AnyEvent::detect
 Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model if
 necessary. You should only call this function right before you would have
 no warnings;
 use strict;
 use Carp;
-our $VERSION = '2.55';
+our $VERSION = '3.1';
 our $MODEL;
 our $AUTOLOAD;
 our @ISA;
 our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
 our @REGISTRY;
 my @models = (
+   [Coro::EV::             => AnyEvent::Impl::CoroEV::],
-   [Coro::Event::          => AnyEvent::Impl::Coro::],
+   [Coro::Event::          => AnyEvent::Impl::CoroEvent::],
-   [EV::                   => EV::AnyEvent::],
+   [EV::                   => AnyEvent::Impl::EV::],
    [Event::                => AnyEvent::Impl::Event::],
    [Glib::                 => AnyEvent::Impl::Glib::],
    [Tk::                   => AnyEvent::Impl::Tk::],
    [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
 );
                last;
             }
          }
          $MODEL
-           or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Event (or Coro+Event), Glib or Tk.";
+           or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event), Glib or Tk.";
       }
       unshift @ISA, $MODEL;
       push @{"$MODEL\::ISA"}, "AnyEvent::Base";
    }
 # default implementation for ->child
 our %PID_CB;
 our $CHLD_W;
+our $CHLD_DELAY_W;
 our $PID_IDLE;
 our $WNOHANG;
 sub _child_wait {
-   while (0 <= (my $pid = waitpid -1, $WNOHANG)) {
+   while (0 < (my $pid = waitpid -1, $WNOHANG)) {
       $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
                          (values %{ $PID_CB{0}    || {} });
    }
    undef $PID_IDLE;
 }
+sub _sigchld {
+   # make sure we deliver these changes "synchronous" with the event loop.
+   $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
+      undef $CHLD_DELAY_W;
+      &_child_wait;
+   });
+}
 sub child {
    my (undef, %arg) = @_;
    defined (my $pid = $arg{pid} + 0)
       or Carp::croak "required option 'pid' is missing";
    unless ($WNOHANG) {
       $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;
    }
    unless ($CHLD_W) {
-      $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_child_wait);
+      $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
-      # child could be a zombie already
+      # child could be a zombie already, so make at least one round
-      $PID_IDLE ||= AnyEvent->timer (after => 0, cb => \&_child_wait);
+      &_sigchld;
    }
    bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
 }
 1. Blocking:
    my $data = $fcp->client_get ($url);
-2. Blocking, but parallelizing:
+2. Blocking, but running in parallel:
    my @datas = map $_->result,
                   map $fcp->txn_client_get ($_),
                      @urls;
 Both blocking examples work without the module user having to know
 anything about events.
-3a. Event-based in a main program, using any support Event module:
+3a. Event-based in a main program, using any supported event module:
-   use Event;
+   use EV;
    $fcp->txn_client_get ($url)->cb (sub {
       my $txn = shift;
       my $data = $txn->result;
       ...
    });
-   Event::loop;
+   EV::loop;
 3b. The module user could use AnyEvent, too:
    use AnyEvent;
    $quit->wait;
 =head1 SEE ALSO
-Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>.
+Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,
+L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>.
-Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>.
+Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,
+L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>,
+L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>.
-Nontrivial usage example: L<Net::FCP>.
+Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
 =head1
 =cut

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.32 by root, Sat Nov 3 09:29:51 2007 UTC vs. Revision 1.51 by root, Wed Apr 16 15:10:10 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.32 by root, Sat Nov 3 09:29:51 2007 UTC vs.
Revision 1.51 by root, Wed Apr 16 15:10:10 2008 UTC