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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC vs.
Revision 1.127 by root, Sat May 24 01:15:19 2008 UTC

-=head1 NAME
+=head1 => NAME
 AnyEvent - provide framework for multiple event loops
 EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
    my $w = AnyEvent->timer (after => $seconds, cb => sub {
       ...
    });
    my $w = AnyEvent->condvar; # stores whether a condition was flagged
+   $w->send; # wake up current and all future recv's
-   $w->wait; # enters "main loop" till $condvar gets ->send
+   $w->recv; # enters "main loop" till $condvar gets ->send
-   $w->send; # 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?
 Example: fork a process and wait for it
   my $done = AnyEvent->condvar;
-  AnyEvent::detect; # force event module to be initialised
   my $pid = fork or exit 5;
   my $w = AnyEvent->child (
      pid => $pid,
      cb  => sub {
         $done->send;
      },
   );
   # do something else, then wait for process exit
-  $done->wait;
+  $done->recv;
 =head2 CONDITION VARIABLES
 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
 Condition variables are very useful to signal that something has finished,
 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.
 Condition variables are represented by hash refs in perl, and the keys
       cb    => sub { $result_ready->send },
    );
    # this "blocks" (while handling events) till the callback
    # calls send
-   $result_ready->wait;
+   $result_ready->recv;
 =head3 METHODS FOR PRODUCERS
 These methods should only be used by the producing side, i.e. the
 code/module that eventually sends the signal. Note that it is also
 =over 4
 =item $cv->send (...)
-Flag the condition as ready - a running C<< ->wait >> and all further
+Flag the condition as ready - a running C<< ->recv >> and all further
-calls to C<wait> will (eventually) return after this method has been
+calls to C<recv> 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<send> 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<Carp::croak> with the given error message/object/scalar.
 This can be used to signal any errors to the condition variable
 user/consumer.
 =item $cv->begin ([group callback])
 =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.
 These methods should only be used by the consuming side, i.e. the
 code awaits the condition.
 =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
 normally.
 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 suppporting blocking waits if the caller so desires).
-Another reason I<never> to C<< ->wait >> in a module is that you cannot
+Another reason I<never> to C<< ->recv >> in a module is that you cannot
-sensibly have two C<< ->wait >>'s in parallel, as that would require
+sensibly have two C<< ->recv >>'s in parallel, as that would require
 multiple interpreters or coroutines/threads, none of which C<AnyEvent>
 can supply.
 The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
 fact, L<Coro::AnyEvent> 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
+You can ensure that C<< -recv >> never blocks by setting a callback and
-only calling C<< ->wait >> from within that callback (or at a later
+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.
 =item $bool = $cv->ready
 This is a mutator function that returns the callback set and optionally
 replaces it before doing so.
 The callback will be called when the condition becomes "true", i.e. when
-C<send> or C<croak> are called. Calling C<wait> inside the callback
+C<send> or C<croak> are called. Calling C<recv> inside the callback
 or at any later time is guaranteed not to block.
 =back
 =head1 GLOBAL VARIABLES AND FUNCTIONS
 Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
 if necessary. You should only call this function right before you would
 have created an AnyEvent watcher anyway, that is, as late as possible at
 runtime.
-=item AnyEvent::on_detect { BLOCK }
+=item $guard = AnyEvent::post_detect { BLOCK }
 Arranges for the code block to be executed as soon as the event model is
 autodetected (or immediately if this has already happened).
+If called in scalar or list context, then it creates and returns an object
+that automatically removes the callback again when it is destroyed. See
+L<Coro::BDB> for a case where this is useful.
-=item @AnyEvent::on_detect
+=item @AnyEvent::post_detect
 If there are any code references in this array (you can C<push> to it
 before or after loading AnyEvent), then they will called directly after
 the event loop has been chosen.
 You should check C<$AnyEvent::MODEL> before adding to this array, though:
 if it contains a true value then the event loop has already been detected,
 and the array will be ignored.
-Best use C<AnyEvent::on_detect { BLOCK }> instead.
+Best use C<AnyEvent::post_detect { BLOCK }> instead.
 =back
 =head1 WHAT TO DO IN A MODULE
 Be careful when you create watchers in the module body - AnyEvent will
 decide which event module to use as soon as the first method is called, so
 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<know> that
+Never call C<< ->recv >> on a condition variable unless you I<know> 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<results> that returns the results, it should call C<< ->wait >>
+called C<results> 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
 There will always be a single main program - the only place that should
 Provide read and write buffers and manages watchers for reads and writes.
 =item L<AnyEvent::Socket>
-Provides a means to do non-blocking connects, accepts etc.
+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<AnyEvent::HTTPD>
 Provides a simple web application server framework.
 =item L<AnyEvent::DNS>
-Provides asynchronous DNS resolver capabilities, beyond what
+Provides rich asynchronous DNS resolver capabilities.
-L<AnyEvent::Util> offers.
 =item L<AnyEvent::FastPing>
 The fastest ping in the west.
 =item L<Coro>
 Has special support for AnyEvent via L<Coro::AnyEvent>.
+=item L<AnyEvent::AIO>, L<IO::AIO>
+Truly asynchronous I/O, should be in the toolbox of every event
+programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
+together.
+=item L<AnyEvent::BDB>, L<BDB>
+Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
+IO::AIO and AnyEvent together.
 =item L<IO::Lambda>
 The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
-=item L<IO::AIO>
-Truly asynchronous I/O, should be in the toolbox of every event
-programmer. Can be trivially made to use AnyEvent.
-=item L<BDB>
-Truly asynchronous Berkeley DB access. Can be trivially made to use
-AnyEvent.
 =back
 =cut
 no warnings;
 use strict;
 use Carp;
-our $VERSION = '3.4';
+our $VERSION = '3.6';
 our $MODEL;
 our $AUTOLOAD;
 our @ISA;
 our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
 our @REGISTRY;
+our %PROTOCOL; # (ipv4|ipv6) => (1|2)
+{
+   my $idx;
+   $PROTOCOL{$_} = ++$idx
+      for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
+}
 my @models = (
    [EV::                   => AnyEvent::Impl::EV::],
    [Event::                => AnyEvent::Impl::Event::],
    [Tk::                   => AnyEvent::Impl::Tk::],
    [POE::Kernel::          => AnyEvent::Impl::POE::],      # lasciate ogni speranza
 );
 our %method = map +($_ => 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) {
-      $_[0]->();
+      $cb->();
+      1
    } else {
-      push @on_detect, $_[0];
+      push @post_detect, $cb;
+      defined wantarray
+         ? bless \$cb, "AnyEvent::Util::PostDetect"
+         : ()
    }
+}
+sub AnyEvent::Util::PostDetect::DESTROY {
+   @post_detect = grep $_ != ${$_[0]}, @post_detect;
 }
 sub detect() {
    unless ($MODEL) {
       no strict 'refs';
       }
       unshift @ISA, $MODEL;
       push @{"$MODEL\::ISA"}, "AnyEvent::Base";
-      (shift @on_detect)->() while @on_detect;
+      (shift @post_detect)->() while @post_detect;
    }
    $MODEL
 }
    $class->$func (@_);
 }
 package AnyEvent::Base;
-# default implementation for ->condvar, ->wait, ->broadcast
+# default implementation for ->condvar
 sub condvar {
-   bless \my $flag, "AnyEvent::Base::CondVar"
+   bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
-}
-sub AnyEvent::Base::CondVar::broadcast {
-   ${$_[0]}++;
-}
-sub AnyEvent::Base::CondVar::wait {
-   AnyEvent->one_event while !${$_[0]};
 }
 # default implementation for ->signal
 our %SIG_CB;
    delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
    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 { $_[0]->send } };
+}
+# undocumented/compatibility with pre-3.4
+*broadcast = \&send;
+*wait      = \&_wait;
 =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
 This is an advanced topic that you do not normally need to use AnyEvent in
 a module. This section is only of use to event loop authors who want to
 provide AnyEvent compatibility.
 For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
 could start your program like this:
   PERL_ANYEVENT_MODEL=Perl perl ...
+=item C<PERL_ANYEVENT_PROTOCOLS>
+Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
+for IPv4 or IPv6. The default is unspecified (and might change, or be the result
+of autoprobing).
+Must be set to a comma-separated list of protocols or address families,
+current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
+used, and preference will be given to protocols mentioned earlier in the
+list.
+This variable can effectively be used for denial-of-service attacks
+against local programs (e.g. when setuid), although the impact is likely
+small, as the program has to handle connection errors already-
+Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
+but support both and try to use both.  C<PERL_ANYEVENT_PROTOCOLS=ipv4>
+- only support IPv4, never try to resolve or contact IPv6
+addressses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
+IPv6, but prefer IPv6 over IPv4.
+=item C<PERL_ANYEVENT_EDNS0>
+Used by L<AnyEvent::DNS> to decide wether to use the EDNS0 extension
+for DNS. This extension is generally useful to reduce DNS traffic, but
+some (broken) firewalls drop such DNS packets, which is why it is off by
+default.
+Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
+EDNS0 in its DNS requests.
 =back
 =head1 EXAMPLE PROGRAM
       poll => 'r',
       cb   => sub {
          warn "io event <$_[0]>\n";   # will always output <r>
          chomp (my $input = <STDIN>); # 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
       },
    );
    my $time_watcher; # can only be used once
       });
    }
    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
 Consider the L<Net::FCP> module. It features (among others) the following
 API calls, which are to freenet what HTTP GET requests are to http:
    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
    }
 The C<result> method, finally, just waits for the finished signal (if the
 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 (C<die>s, exceptions)
 that occured during request processing. The C<result> method detects
 whether an exception as thrown (it is stored inside the $txn object)
    my $quit = AnyEvent->condvar;
    $fcp->txn_client_get ($url)->cb (sub {
       ...
-      $quit->broadcast;
+      $quit->send;
    });
-   $quit->wait;
+   $quit->recv;
 =head1 BENCHMARKS
 To give you an idea of the performance and overheads that AnyEvent adds
 all watchers, to avoid adding memory overhead. That means closure creation
 and memory usage is not included in the figures.
 I<invoke> 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<destroy> is the time, in microseconds, that it takes to destroy a single
 watcher.
 probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
 =head1 SEE ALSO
+Utility functions: L<AnyEvent::Util>.
 Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
 L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
 Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
 L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
 L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
 L<AnyEvent::Impl::POE>.
+Non-blocking file handles, sockets, TCP clients and
+servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
+Asynchronous DNS: L<AnyEvent::DNS>.
 Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
-Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
+Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
 =head1 AUTHOR
  Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC vs. Revision 1.127 by root, Sat May 24 01:15:19 2008 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.109 by root, Sat May 10 00:45:18 2008 UTC vs.
Revision 1.127 by root, Sat May 24 01:15:19 2008 UTC