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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.195 by root, Wed Mar 25 17:33:11 2009 UTC vs.
Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC

 =head1 SYNOPSIS
    use AnyEvent;
+   # file descriptor readable
-   my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ...  });
+   my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ...  });
+   # one-shot or repeating timers
    my $w = AnyEvent->timer (after => $seconds, cb => sub { ...  });
    my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
    print AnyEvent->now;  # prints current event loop time
    print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
+   # POSIX signal
    my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
+   # child process exit
    my $w = AnyEvent->child (pid => $pid, cb => sub {
       my ($pid, $status) = @_;
       ...
    });
+   # called when event loop idle (if applicable)
+   my $w = AnyEvent->idle (cb => sub { ... });
    my $w = AnyEvent->condvar; # stores whether a condition was flagged
    $w->send; # wake up current and all future recv's
    $w->recv; # enters "main loop" till $condvar gets ->send
    # use a condvar in callback mode:
 These watchers are normal Perl objects with normal Perl lifetime. After
 creating a watcher it will immediately "watch" for events and invoke the
 callback when the event occurs (of course, only when the event model
 is in control).
+Note that B<callbacks must not permanently change global variables>
+potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
+callbacks must not C<die> >>. The former is good programming practise in
+Perl and the latter stems from the fact that exception handling differs
+widely between event loops.
 To disable the watcher you have to destroy it (e.g. by setting the
 variable you store it in to C<undef> or otherwise deleting all references
 to it).
 All watchers are created by calling a method on the C<AnyEvent> class.
 =head2 I/O WATCHERS
 You can create an I/O watcher by calling the C<< AnyEvent->io >> method
 with the following mandatory key-value pairs as arguments:
-C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
+C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
-(AnyEvent might or might not keep a reference to this file handle). C<poll>
+for events (AnyEvent might or might not keep a reference to this file
+handle). Note that only file handles pointing to things for which
+non-blocking operation makes sense are allowed. This includes sockets,
+most character devices, pipes, fifos and so on, but not for example files
+or block devices.
-must be a string that is either C<r> or C<w>, which creates a watcher
+C<poll> must be a string that is either C<r> or C<w>, which creates a
-waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
+watcher waiting for "r"eadable or "w"ritable events, respectively.
-callback to invoke each time the file handle becomes ready.
+C<cb> is the callback to invoke each time the file handle becomes ready.
 Although the callback might get passed parameters, their value and
 presence is undefined and you cannot rely on them. Portable AnyEvent
 callbacks cannot use arguments passed to I/O watcher callbacks.
 In either case, if you care (and in most cases, you don't), then you
 can get whatever behaviour you want with any event loop, by taking the
 difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
 account.
+=item AnyEvent->now_update
+Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
+the current time for each loop iteration (see the discussion of L<<
+AnyEvent->now >>, above).
+When a callback runs for a long time (or when the process sleeps), then
+this "current" time will differ substantially from the real time, which
+might affect timers and time-outs.
+When this is the case, you can call this method, which will update the
+event loop's idea of "current time".
+Note that updating the time I<might> cause some events to be handled.
 =back
 =head2 SIGNAL WATCHERS
    );
    # do something else, then wait for process exit
    $done->recv;
+=head2 IDLE WATCHERS
+Sometimes there is a need to do something, but it is not so important
+to do it instantly, but only when there is nothing better to do. This
+"nothing better to do" is usually defined to be "no other events need
+attention by the event loop".
+Idle watchers ideally get invoked when the event loop has nothing
+better to do, just before it would block the process to wait for new
+events. Instead of blocking, the idle watcher is invoked.
+Most event loops unfortunately do not really support idle watchers (only
+EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
+will simply call the callback "from time to time".
+Example: read lines from STDIN, but only process them when the
+program is otherwise idle:
+   my @lines; # read data
+   my $idle_w;
+   my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
+      push @lines, scalar <STDIN>;
+      # start an idle watcher, if not already done
+      $idle_w ||= AnyEvent->idle (cb => sub {
+         # handle only one line, when there are lines left
+         if (my $line = shift @lines) {
+            print "handled when idle: $line";
+         } else {
+            # otherwise disable the idle watcher again
+            undef $idle_w;
+         }
+      });
+   });
 =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
 will actively watch for new events and call your callbacks.
 no warnings;
 use strict qw(vars subs);
 use Carp;
-our $VERSION = 4.341;
+our $VERSION = 4.4;
 our $MODEL;
 our $AUTOLOAD;
 our @ISA;
    [POE::Kernel::          => AnyEvent::Impl::POE::],      # lasciate ogni speranza
    [Wx::                   => AnyEvent::Impl::POE::],
    [Prima::                => AnyEvent::Impl::POE::],
 );
-our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
+our %method = map +($_ => 1),
+   qw(io timer time now now_update signal child idle condvar one_event DESTROY);
 our @post_detect;
 sub post_detect(&) {
    my ($cb) = @_;
       1
    } else {
       push @post_detect, $cb;
       defined wantarray
-         ? bless \$cb, "AnyEvent::Util::PostDetect"
+         ? bless \$cb, "AnyEvent::Util::postdetect"
          : ()
    }
 }
-sub AnyEvent::Util::PostDetect::DESTROY {
+sub AnyEvent::Util::postdetect::DESTROY {
    @post_detect = grep $_ != ${$_[0]}, @post_detect;
 }
 sub detect() {
    unless ($MODEL) {
                   last;
                }
             }
             $MODEL
-              or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
+              or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
          }
       }
       push @{"$MODEL\::ISA"}, "AnyEvent::Base";
    my ($rw, $mode) = $poll eq "r" ? ($r, "<")
                    : $poll eq "w" ? ($w, ">")
                    : Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
    open my $fh2, "$mode&" . fileno $fh
-      or die "cannot dup() filehandle: $!";
+      or die "cannot dup() filehandle: $!,";
    # we assume CLOEXEC is already set by perl in all important cases
    ($fh2, $rw)
 }
 package AnyEvent::Base;
-# default implementation for now and time
+# default implementations for many methods
 BEGIN {
-   if (eval "use Time::HiRes (); time (); 1") {
+   if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
       *_time = \&Time::HiRes::time;
       # if (eval "use POSIX (); (POSIX::times())...
    } else {
       *_time = sub { time }; # epic fail
    }
 }
 sub time { _time }
 sub now  { _time }
+sub now_update { }
 # default implementation for ->condvar
 sub condvar {
-   bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
+   bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
 }
 # default implementation for ->signal
 our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
 sub _signal_exec {
+   sysread $SIGPIPE_R, my $dummy, 4;
    while (%SIG_EV) {
-      sysread $SIGPIPE_R, my $dummy, 4;
       for (keys %SIG_EV) {
          delete $SIG_EV{$_};
          $_->() for values %{ $SIG_CB{$_} || {} };
       }
    }
 sub signal {
    my (undef, %arg) = @_;
    unless ($SIGPIPE_R) {
+      require Fcntl;
       if (AnyEvent::WIN32) {
+         require AnyEvent::Util;
          ($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
          AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
          AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
       } else {
          pipe $SIGPIPE_R, $SIGPIPE_W;
-         require Fcntl;
          fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
          fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
       }
       $SIGPIPE_R
          or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
+      # not strictly required, as $^F is normally 2, but let's make sure...
+      fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
+      fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
       $SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
    }
    my $signal = uc $arg{signal}
       or Carp::croak "required option 'signal' is missing";
    $SIG_CB{$signal}{$arg{cb}} = $arg{cb};
    $SIG{$signal} ||= sub {
+      local $!;
       syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
       undef $SIG_EV{$signal};
    };
-   bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
+   bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
 }
-sub AnyEvent::Base::Signal::DESTROY {
+sub AnyEvent::Base::signal::DESTROY {
    my ($signal, $cb) = @{$_[0]};
    delete $SIG_CB{$signal}{$cb};
    delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
       $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
       # child could be a zombie already, so make at least one round
       &_sigchld;
    }
-   bless [$pid, $arg{cb}], "AnyEvent::Base::Child"
+   bless [$pid, $arg{cb}], "AnyEvent::Base::child"
 }
-sub AnyEvent::Base::Child::DESTROY {
+sub AnyEvent::Base::child::DESTROY {
    my ($pid, $cb) = @{$_[0]};
    delete $PID_CB{$pid}{$cb};
    delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
    undef $CHLD_W unless keys %PID_CB;
+}
+# idle emulation is done by simply using a timer, regardless
+# of whether the proces sis idle or not, and not letting
+# the callback use more than 50% of the time.
+sub idle {
+   my (undef, %arg) = @_;
+   my ($cb, $w, $rcb) = $arg{cb};
+   $rcb = sub {
+      if ($cb) {
+         $w = _time;
+         &$cb;
+         $w = _time - $w;
+         # never use more then 50% of the time for the idle watcher,
+         # within some limits
+         $w = 0.0001 if $w < 0.0001;
+         $w = 5      if $w > 5;
+         $w = AnyEvent->timer (after => $w, cb => $rcb);
+      } else {
+         # clean up...
+         undef $w;
+         undef $rcb;
+      }
+   };
+   $w = AnyEvent->timer (after => 0.05, cb => $rcb);
+   bless \\$cb, "AnyEvent::Base::idle"
+}
+sub AnyEvent::Base::idle::DESTROY {
+   undef $${$_[0]};
 }
 package AnyEvent::CondVar;
 our @ISA = AnyEvent::CondVar::Base::;
 =head1 BUGS
 Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
 to work around. If you suffer from memleaks, first upgrade to Perl 5.10
 and check wether the leaks still show up. (Perl 5.10.0 has other annoying
-mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
+memleaks, such as leaking on C<map> and C<grep> but it is usually not as
 pronounced).
 =head1 SEE ALSO

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.195 by root, Wed Mar 25 17:33:11 2009 UTC vs. Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.195 by root, Wed Mar 25 17:33:11 2009 UTC vs.
Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC