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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.380 by root, Thu Sep 1 04:07:18 2011 UTC vs.
Revision 1.389 by root, Tue Oct 4 05:34:50 2011 UTC

 not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
 pure perl implementation).
 =head3 Safe/Unsafe Signals
-Perl signals can be either "safe" (synchronous to opcode handling) or
+Perl signals can be either "safe" (synchronous to opcode handling)
-"unsafe" (asynchronous) - the former might get delayed indefinitely, the
+or "unsafe" (asynchronous) - the former might delay signal delivery
-latter might corrupt your memory.
+indefinitely, the latter might corrupt your memory.
 AnyEvent signal handlers are, in addition, synchronous to the event loop,
 i.e. they will not interrupt your running perl program but will only be
 called as part of the normal event handling (just like timer, I/O etc.
 callbacks, too).
 =head3 Signal Races, Delays and Workarounds
-Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
+Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
-callbacks to signals in a generic way, which is a pity, as you cannot
+attaching callbacks to signals in a generic way, which is a pity,
-do race-free signal handling in perl, requiring C libraries for
+as you cannot do race-free signal handling in perl, requiring
-this. AnyEvent will try to do its best, which means in some cases,
+C libraries for this. AnyEvent will try to do its best, which
-signals will be delayed. The maximum time a signal might be delayed is
+means in some cases, signals will be delayed. The maximum time
-specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
+a signal might be delayed is 10 seconds by default, but can
-variable can be changed only before the first signal watcher is created,
+be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
-and should be left alone otherwise. This variable determines how often
+C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the Ö<ENVIRONMENT VARIABLES>
-AnyEvent polls for signals (in case a wake-up was missed). Higher values
+section for details.
-will cause fewer spurious wake-ups, which is better for power and CPU
-saving.
 All these problems can be avoided by installing the optional
 L<Async::Interrupt> module, which works with most event loops. It will not
 work with inherently broken event loops such as L<Event> or L<Event::Lib>
-(and not with L<POE> currently, as POE does its own workaround with
+(and not with L<POE> currently). For those, you just have to suffer the
-one-second latency). For those, you just have to suffer the delays.
+delays.
 =head2 CHILD PROCESS WATCHERS
    $w = AnyEvent->child (pid => <process id>, cb => <callback>);
 use Carp ();
 our $VERSION = '6.02';
 our $MODEL;
 our @ISA;
 our @REGISTRY;
 our $VERBOSE;
+our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
+our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
 BEGIN {
    require "AnyEvent/constants.pl";
    eval "sub TAINT (){" . (${^TAINT}*1) . "}";
       for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
    @ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
       if ${^TAINT};
+   # $ENV{PERL_ANYEVENT_xxx} now valid
-   $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 3;
+   $VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
-}
-our $MAX_SIGNAL_LATENCY = 10;
-our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
-{
    my $idx;
    $PROTOCOL{$_} = ++$idx
       for reverse split /\s*,\s*/,
              $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
 }
    ()
 }
 sub log($$;@) {
    # only load the big bloated module when we actually are about to log something
-   if ($_[0] <= $VERBOSE) { # also catches non-numeric levels(!)
+   if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
-      require AnyEvent::Log;
+      local ($!, $@);
+      require AnyEvent::Log; # among other things, sets $VERBOSE to 9
       # AnyEvent::Log overwrites this function
       goto &log;
    }
    0 # not logged
 }
+sub _logger($;$) {
+   my ($level, $renabled) = @_;
+   $$renabled = $level <= $VERBOSE;
+   my $logger = [(caller)[0], $level, $renabled];
+   $AnyEvent::Log::LOGGER{$logger+0} = $logger;
+#   return unless defined wantarray;
+#
+#   require AnyEvent::Util;
+#   my $guard = AnyEvent::Util::guard (sub {
+#      # "clean up"
+#      delete $LOGGER{$logger+0};
+#   });
+#
+#   sub {
+#      return 0 unless $$renabled;
+#
+#      $guard if 0; # keep guard alive, but don't cause runtime overhead
+#      require AnyEvent::Log unless $AnyEvent::Log::VERSION;
+#      package AnyEvent::Log;
+#      _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
+#   }
+}
 if (length $ENV{PERL_ANYEVENT_LOG}) {
    require AnyEvent::Log; # AnyEvent::Log does the thing for us
 }
 our @models = (
-   [EV::                   => AnyEvent::Impl::EV::   , 1],
+   [EV::                   => AnyEvent::Impl::EV::],
-   [AnyEvent::Loop::       => AnyEvent::Impl::Perl:: , 1],
+   [AnyEvent::Loop::       => AnyEvent::Impl::Perl::],
    # everything below here will not (normally) be autoprobed
    # as the pure perl backend should work everywhere
    # and is usually faster
+   [Irssi::                => AnyEvent::Impl::Irssi::],    # Irssi has a bogus "Event" package, so msut be near the top
-   [Event::                => AnyEvent::Impl::Event::, 1],
+   [Event::                => AnyEvent::Impl::Event::],    # slow, stable
-   [Glib::                 => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
+   [Glib::                 => AnyEvent::Impl::Glib::],     # becomes extremely slow with many watchers
+   # everything below here should not be autoloaded
    [Event::Lib::           => AnyEvent::Impl::EventLib::], # too buggy
-   [Irssi::                => AnyEvent::Impl::Irssi::],    # Irssi has a bogus "Event" package
    [Tk::                   => AnyEvent::Impl::Tk::],       # crashes with many handles
    [Qt::                   => AnyEvent::Impl::Qt::],       # requires special main program
    [POE::Kernel::          => AnyEvent::Impl::POE::],      # lasciate ogni speranza
    [Wx::                   => AnyEvent::Impl::POE::],
    [Prima::                => AnyEvent::Impl::POE::],
 our @methods = qw(io timer time now now_update signal child idle condvar);
 sub detect() {
    return $MODEL if $MODEL; # some programs keep references to detect
+   # IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
+   # the author knows about the problems and what it does to AnyEvent as a whole
+   # (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
+   # anyway.
+   AnyEvent::log fatal => "AnyEvent: IO::Async::Loop::AnyEvent detected - this module is broken by design,\n"
+                          . "abuses internals and breaks AnyEvent, will not continue."
+      if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
    local $!; # for good measure
    local $SIG{__DIE__}; # we use eval
    # free some memory
    *detect = sub () { $MODEL };
       $model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
       if (eval "require $model") {
          AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
          $MODEL = $model;
       } else {
-         AnyEvent::log 5 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
+         AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
       }
    }
    # check for already loaded models
    unless ($MODEL) {
       }
       unless ($MODEL) {
          # try to autoload a model
          for (@REGISTRY, @models) {
-            my ($package, $model, $autoload) = @$_;
+            my ($package, $model) = @$_;
             if (
-               $autoload
-               and eval "require $package"
+               eval "require $package"
                and ${"$package\::VERSION"} > 0
                and eval "require $model"
             ) {
                AnyEvent::log 7 => "autoloaded model '$model', using it.";
                $MODEL = $model;
                last;
             }
          }
          $MODEL
-           or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
+           or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
       }
    }
    # free memory only needed for probing
    undef @models;
 C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
 can be very useful, however.
 =item C<PERL_ANYEVENT_DEBUG_SHELL>
-If this env variable is set, then its contents will be interpreted by
+If this env variable is nonempty, then its contents will be interpreted by
-C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
+C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
-C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
+replacing every occurance of C<$$> by the process pid). The shell object
-that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
+is saved in C<$AnyEvent::Debug::SHELL>.
 This happens when the first watcher is created.
 For example, to bind a debug shell on a unix domain socket in
 F<< /tmp/debug<pid>.sock >>, you could use this:
    PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
+   # connect with e.g.: socat readline /tmp/debug123.sock
+Or to bind to tcp port 4545 on localhost:
+   PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
+   # connect with e.g.: telnet localhost 4545
-Note that creating sockets in F</tmp> is very unsafe on multiuser
+Note that creating sockets in F</tmp> or on localhost is very unsafe on
-systems.
+multiuser systems.
 =item C<PERL_ANYEVENT_DEBUG_WRAP>
 Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
 debugging purposes. See C<AnyEvent::Debug::wrap> for details.
 =item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
 The default value for the C<max_outstanding> parameter for the default DNS
 resolver - this is the maximum number of parallel DNS requests that are
 sent to the DNS server.
+=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
+Perl has inherently racy signal handling (you can basically choose between
+losing signals and memory corruption) - pure perl event loops (including
+C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
+have to poll regularly to avoid losing signals.
+Some event loops are racy, but don't poll regularly, and some event loops
+are written in C but are still racy. For those event loops, AnyEvent
+installs a timer that regularly wakes up the event loop.
+By default, the interval for this timer is C<10> seconds, but you can
+override this delay with this environment variable (or by setting
+the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
+watchers).
+Lower values increase CPU (and energy) usage, higher values can introduce
+long delays when reaping children or waiting for signals.
+The L<AnyEvent::Async> module, if available, will be used to avoid this
+polling (with most event loops).
 =item C<PERL_ANYEVENT_RESOLV_CONF>
 The absolute path to a F<resolv.conf>-style file to use instead of
 F</etc/resolv.conf> (or the OS-specific configuration) in the default

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.380 by root, Thu Sep 1 04:07:18 2011 UTC vs. Revision 1.389 by root, Tue Oct 4 05:34:50 2011 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.380 by root, Thu Sep 1 04:07:18 2011 UTC vs.
Revision 1.389 by root, Tue Oct 4 05:34:50 2011 UTC