Coro/Event/Event.pm

=head1 NAME

Coro::Event - do events the coro-way

=head1 SYNOPSIS

 use Coro;
 use Coro::Event;

 sub keyboard : Coro {
    my $w = Coro::Event->io(fd => *STDIN, poll => 'r');
    while() {
       print "cmd> ";
       my $ev = $w->next; my $cmd = <STDIN>;
       unloop unless $cmd ne "";
       print "data> ";
       my $ev = $w->next; my $data = <STDIN>;
    }
 }

 &loop;

=head1 DESCRIPTION

This module enables you to create programs using the powerful Event model
(and module), while retaining the linear style known from simple or
threaded programs.

This module provides a method and a function for every watcher type
(I<flavour>) (see L<Event>). The only difference between these and the
watcher constructors from Event is that you do not specify a callback
function - it will be managed by this module.

Your application should just create all necessary coroutines and then call
Coro::Event->main.

=over 4

=cut

package Coro::Event;

no warnings;

use Carp;

use Coro;
use Event qw(unloop); # we are re-exporting this, cooool!

use base 'Exporter';

@EXPORT = qw(loop unloop sweep);

$VERSION = 0.45;

=item $w = Coro::Event->flavour(args...)

Create and return a watcher of the given type.

Examples:

  my $reader = Coro::Event->io(fd => $filehandle, poll => 'r');
  $reader->next;

=cut

=item $w->next

Return the next event of the event queue of the watcher.

=cut

=item do_flavour(args...)

Create a watcher of the given type and immediately call it's next
method. This is less efficient then calling the constructor once and the
next method often, but it does save typing sometimes.

=cut

#Event->add_hooks(prepare => sub {
#   &Coro::cede while &Coro::nready;
#   1e6;
#});

sub std_cb {
   my $w = $_[0]->w;
   my $q = $w->private;
   $q->[1] = $_[0];
   if ($q->[0]) { # somebody waiting?
      $q->[0]->ready;
      &Coro::schedule;
   } else {
      $w->stop;
   }
}

for my $flavour (qw(idle var timer io signal)) {
   push @EXPORT, "do_$flavour";
   my $new = \&{"Event::$flavour"};
   my $class = "Coro::Event::$flavour";
   @{"${class}::ISA"} = (Coro::Event::, "Event::$flavour");
   my $coronew = sub {
      # how does one do method-call-by-name?
      # my $w = $class->SUPER::$flavour(@_);

      $_[0] eq Coro::Event::
         or croak "event constructor \"Coro::Event->$flavour\" must be called as a static method";

      my $q = []; # [$coro, $event]
      my $w = $new->(
            desc => $flavour,
            @_,
            cb => \&std_cb,
      );
      $w->private($q); # using private as attribute is pretty useless...
      bless $w, $class; # reblessing due to broken Event
   };
   *{    $flavour } = $coronew;
   *{"do_$flavour"} = sub {
      unshift @_, Coro::Event::;
      my $e = (&$coronew)->next;
      $e->w->cancel;
      $e;
   };
}

sub next {
   my $w = $_[0];
   my $q = $w->private;
   if ($q->[1]) { # event waiting?
      $w->again unless $w->is_cancelled;
   } elsif ($q->[0]) {
      croak "only one coroutine can wait for an event";
   } else {
      local $q->[0] = $Coro::current;
      &Coro::schedule;
   }
   pop @$q;
}

=item sweep

Similar to Event::one_event and Event::sweep: The idle task is called once
(this has the effect of jumping back into the Event loop once to serve new
events).

The reason this function exists is that you sometimes want to serve events
while doing other work. Calling C<Coro::cede> does not work because
C<cede> implies that the current coroutine is runnable and does not call
into the Event dispatcher.

=cut

sub sweep {
   one_event(0); # for now
}

=item $result = loop([$timeout])

This is the version of C<loop> you should use instead of C<Event::loop>
when using this module - it will ensure correct scheduling in the presence
of events.

=begin comment

Unlike loop's counterpart it is not an error when no watchers are active -
loop silently returns in this case, as if unloop(undef) were called.

=end comment

=cut

sub loop(;$) {
   local $Coro::idle = $Coro::current;
   Coro::schedule; # become idle task, which is implicitly ready
   &Event::loop;
}

=item unloop([$result])

Same as Event::unloop (provided here for your convinience only).

=cut

$Coro::idle = new Coro sub {
   while () {
      Event::one_event; # inefficient
      Coro::schedule;
   }
};

1;

=head1 AUTHOR

 Marc Lehmann <pcg@goof.com>
 http://www.goof.com/pcg/marc/

=cut

Revision:	1.1
Committed:	Thu Aug 16 21:55:34 2001 UTC (22 years, 10 months ago) by root
Branch:	MAIN
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			Coro::Event - do events the coro-way
4
5			=head1 SYNOPSIS
6
7			use Coro;
8			use Coro::Event;
9
10			sub keyboard : Coro {
11			my $w = Coro::Event->io(fd => *STDIN, poll => 'r');
12			while() {
13			print "cmd> ";
14			my $ev = $w->next; my $cmd = <STDIN>;
15			unloop unless $cmd ne "";
16			print "data> ";
17			my $ev = $w->next; my $data = <STDIN>;
18			}
19			}
20
21			&loop;
22
23			=head1 DESCRIPTION
24
25			This module enables you to create programs using the powerful Event model
26			(and module), while retaining the linear style known from simple or
27			threaded programs.
28
29			This module provides a method and a function for every watcher type
30			(I<flavour>) (see L<Event>). The only difference between these and the
31			watcher constructors from Event is that you do not specify a callback
32			function - it will be managed by this module.
33
34			Your application should just create all necessary coroutines and then call
35			Coro::Event->main.
36
37			=over 4
38
39			=cut
40
41			package Coro::Event;
42
43			no warnings;
44
45			use Carp;
46
47			use Coro;
48			use Event qw(unloop); # we are re-exporting this, cooool!
49
50			use base 'Exporter';
51
52			@EXPORT = qw(loop unloop sweep);
53
54			$VERSION = 0.45;
55
56			=item $w = Coro::Event->flavour(args...)
57
58			Create and return a watcher of the given type.
59
60			Examples:
61
62			my $reader = Coro::Event->io(fd => $filehandle, poll => 'r');
63			$reader->next;
64
65			=cut
66
67			=item $w->next
68
69			Return the next event of the event queue of the watcher.
70
71			=cut
72
73			=item do_flavour(args...)
74
75			Create a watcher of the given type and immediately call it's next
76			method. This is less efficient then calling the constructor once and the
77			next method often, but it does save typing sometimes.
78
79			=cut
80
81			#Event->add_hooks(prepare => sub {
82			# &Coro::cede while &Coro::nready;
83			# 1e6;
84			#});
85
86			sub std_cb {
87			my $w = $_[0]->w;
88			my $q = $w->private;
89			$q->[1] = $_[0];
90			if ($q->[0]) { # somebody waiting?
91			$q->[0]->ready;
92			&Coro::schedule;
93			} else {
94			$w->stop;
95			}
96			}
97
98			for my $flavour (qw(idle var timer io signal)) {
99			push @EXPORT, "do_$flavour";
100			my $new = \&{"Event::$flavour"};
101			my $class = "Coro::Event::$flavour";
102			@{"${class}::ISA"} = (Coro::Event::, "Event::$flavour");
103			my $coronew = sub {
104			# how does one do method-call-by-name?
105			# my $w = $class->SUPER::$flavour(@_);
106
107			$_[0] eq Coro::Event::
108			or croak "event constructor \"Coro::Event->$flavour\" must be called as a static method";
109
110			my $q = []; # [$coro, $event]
111			my $w = $new->(
112			desc => $flavour,
113			@_,
114			cb => \&std_cb,
115			);
116			$w->private($q); # using private as attribute is pretty useless...
117			bless $w, $class; # reblessing due to broken Event
118			};
119			*{ $flavour } = $coronew;
120			*{"do_$flavour"} = sub {
121			unshift @_, Coro::Event::;
122			my $e = (&$coronew)->next;
123			$e->w->cancel;
124			$e;
125			};
126			}
127
128			sub next {
129			my $w = $_[0];
130			my $q = $w->private;
131			if ($q->[1]) { # event waiting?
132			$w->again unless $w->is_cancelled;
133			} elsif ($q->[0]) {
134			croak "only one coroutine can wait for an event";
135			} else {
136			local $q->[0] = $Coro::current;
137			&Coro::schedule;
138			}
139			pop @$q;
140			}
141
142			=item sweep
143
144			Similar to Event::one_event and Event::sweep: The idle task is called once
145			(this has the effect of jumping back into the Event loop once to serve new
146			events).
147
148			The reason this function exists is that you sometimes want to serve events
149			while doing other work. Calling C<Coro::cede> does not work because
150			C<cede> implies that the current coroutine is runnable and does not call
151			into the Event dispatcher.
152
153			=cut
154
155			sub sweep {
156			one_event(0); # for now
157			}
158
159			=item $result = loop([$timeout])
160
161			This is the version of C<loop> you should use instead of C<Event::loop>
162			when using this module - it will ensure correct scheduling in the presence
163			of events.
164
165			=begin comment
166
167			Unlike loop's counterpart it is not an error when no watchers are active -
168			loop silently returns in this case, as if unloop(undef) were called.
169
170			=end comment
171
172			=cut
173
174			sub loop(;$) {
175			local $Coro::idle = $Coro::current;
176			Coro::schedule; # become idle task, which is implicitly ready
177			&Event::loop;
178			}
179
180			=item unloop([$result])
181
182			Same as Event::unloop (provided here for your convinience only).
183
184			=cut
185
186			$Coro::idle = new Coro sub {
187			while () {
188			Event::one_event; # inefficient
189			Coro::schedule;
190			}
191			};
192
193			1;
194
195			=head1 AUTHOR
196
197			Marc Lehmann <pcg@goof.com>
198			http://www.goof.com/pcg/marc/
199
200			=cut
201