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;

 # wait for input on stdin for one second
 
 Coro::Event::do_io (fd => \*STDIN, timeout => 1) & Event::Watcher::R
    or die "no input received";

=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::loop.

Please note that even programs or modules (such as
L<Coro::Handle|Coro::Handle>) that use "traditional"
event-based/continuation style will run more efficient with this module
then when using only Event.

=head1 WARNING

Please note that Event does not support coroutines or threads. That
means that you B<MUST NOT> block in an event callback. Again: In Event
callbacks, you I<must never ever> call a Coroutine fucntion that blocks
the current coroutine.

While this seems to work superficially, it will eventually cause memory
corruption.

=head1 SEMANTICS

Whenever Event blocks (e.g. in a call to C<one_event>, C<loop> etc.),
this module cede's to all other coroutines with the same or higher
priority. When any coroutines of lower priority are ready, it will not
block but run one of them and then check for events.

The effect is that coroutines with the same or higher priority than
the blocking coroutine will keep Event from checking for events, while
coroutines with lower priority are being run, but Event checks for new
events after every cede.

=head1 FUNCTIONS

=over 4

=cut

package Coro::Event;

no warnings;

use Carp;
no warnings;

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

use XSLoader;

use base Exporter::;

our @EXPORT = qw(loop unloop sweep);

BEGIN {
   our $VERSION = '2.1';

   local $^W = 0; # avoid redefine warning for Coro::ready;
   XSLoader::load __PACKAGE__, $VERSION;
}

=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

Wait for and return the next event of the event queue of the watcher. The
returned event objects support two methods only: C<hits> and C<got>, both
of which return integers: the number this watcher was hit for this event,
and the mask of poll events received.

=cut

=item do_flavour args...

Create a watcher of the given type and immediately call it's next method,
returning the event.

This is less efficient then calling the constructor once and the next
method often, but it does save typing sometimes.

=cut

for my $flavour (qw(idle var timer io signal)) {
   push @EXPORT, "do_$flavour";
   my $new = \&{"Event::$flavour"};
   my $class = "Coro::Event::$flavour";
   my $type = $flavour eq "io" ? 1 : 0;
   @{"${class}::ISA"} = (Coro::Event::, "Event::$flavour");
   my $coronew = sub {
      # how does one do method-call-by-name?
      # my $w = $class->SUPER::$flavour(@_);

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

      my $w = $new->($class,
         desc   => $flavour,
         @_,
         parked => 1,
      );

      _install_std_cb $w, $type;
      
      # reblessing due to Event being broken
      bless $w, $class
   };
   *{    $flavour } = $coronew;
   *{"do_$flavour"} = sub {
      unshift @_, Coro::Event::;
      next_cancel (&$coronew);
   };
}

sub Coro::Event::Event::hits { $_[0][3] }
sub Coro::Event::Event::got  { $_[0][4] }

=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 {
   Event::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.

=item unloop([$result])

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

=cut

$Coro::idle = \&Event::one_event; # inefficient

1;

=back

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

Revision:	1.49
Committed:	Tue Oct 9 22:29:27 2007 UTC (16 years, 9 months ago) by root
Branch:	MAIN
Changes since 1.48:	+4 -15 lines
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	pcg	1.21	my $w = Coro::Event->io(fd => \*STDIN, poll => 'r');
12	root	1.1	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	root	1.8	loop;
22	root	1.1
23	root	1.47	# wait for input on stdin for one second
24
25			Coro::Event::do_io (fd => \*STDIN, timeout => 1) & Event::Watcher::R
26			or die "no input received";
27
28	root	1.1	=head1 DESCRIPTION
29
30			This module enables you to create programs using the powerful Event model
31			(and module), while retaining the linear style known from simple or
32			threaded programs.
33
34			This module provides a method and a function for every watcher type
35			(I<flavour>) (see L<Event>). The only difference between these and the
36			watcher constructors from Event is that you do not specify a callback
37			function - it will be managed by this module.
38
39			Your application should just create all necessary coroutines and then call
40	root	1.12	Coro::Event::loop.
41	root	1.1
42	root	1.37	Please note that even programs or modules (such as
43			L<Coro::Handle\|Coro::Handle>) that use "traditional"
44			event-based/continuation style will run more efficient with this module
45			then when using only Event.
46
47	root	1.42	=head1 WARNING
48
49			Please note that Event does not support coroutines or threads. That
50			means that you B<MUST NOT> block in an event callback. Again: In Event
51			callbacks, you I<must never ever> call a Coroutine fucntion that blocks
52			the current coroutine.
53
54			While this seems to work superficially, it will eventually cause memory
55			corruption.
56
57	root	1.45	=head1 SEMANTICS
58
59	root	1.46	Whenever Event blocks (e.g. in a call to C<one_event>, C<loop> etc.),
60	root	1.45	this module cede's to all other coroutines with the same or higher
61			priority. When any coroutines of lower priority are ready, it will not
62			block but run one of them and then check for events.
63
64			The effect is that coroutines with the same or higher priority than
65			the blocking coroutine will keep Event from checking for events, while
66			coroutines with lower priority are being run, but Event checks for new
67			events after every cede.
68
69	root	1.42	=head1 FUNCTIONS
70
71	root	1.1	=over 4
72
73			=cut
74
75			package Coro::Event;
76
77	root	1.42	no warnings;
78	root	1.1
79			use Carp;
80	root	1.30	no warnings;
81	root	1.1
82			use Coro;
83	root	1.40	use Coro::Timer;
84	root	1.8	use Event qw(loop unloop); # we are re-exporting this, cooool!
85	root	1.1
86	root	1.30	use XSLoader;
87	root	1.1
88	root	1.30	use base Exporter::;
89
90	root	1.41	our @EXPORT = qw(loop unloop sweep);
91	root	1.1
92	root	1.2	BEGIN {
93	root	1.48	our $VERSION = '2.1';
94	root	1.2
95	root	1.13	local $^W = 0; # avoid redefine warning for Coro::ready;
96	root	1.30	XSLoader::load __PACKAGE__, $VERSION;
97	root	1.2	}
98	root	1.1
99	root	1.42	=item $w = Coro::Event->flavour (args...)
100	root	1.1
101			Create and return a watcher of the given type.
102
103			Examples:
104
105			my $reader = Coro::Event->io(fd => $filehandle, poll => 'r');
106			$reader->next;
107
108			=cut
109
110			=item $w->next
111
112	root	1.47	Wait for and return the next event of the event queue of the watcher. The
113			returned event objects support two methods only: C<hits> and C<got>, both
114			of which return integers: the number this watcher was hit for this event,
115			and the mask of poll events received.
116	root	1.1
117			=cut
118
119	root	1.42	=item do_flavour args...
120	root	1.1
121	root	1.47	Create a watcher of the given type and immediately call it's next method,
122			returning the event.
123
124			This is less efficient then calling the constructor once and the next
125			method often, but it does save typing sometimes.
126	root	1.1
127			=cut
128
129			for my $flavour (qw(idle var timer io signal)) {
130			push @EXPORT, "do_$flavour";
131			my $new = \&{"Event::$flavour"};
132			my $class = "Coro::Event::$flavour";
133	root	1.2	my $type = $flavour eq "io" ? 1 : 0;
134	root	1.1	@{"${class}::ISA"} = (Coro::Event::, "Event::$flavour");
135			my $coronew = sub {
136			# how does one do method-call-by-name?
137			# my $w = $class->SUPER::$flavour(@_);
138
139	root	1.10	shift eq Coro::Event::
140	root	1.1	or croak "event constructor \"Coro::Event->$flavour\" must be called as a static method";
141
142	root	1.10	my $w = $new->($class,
143	root	1.49	desc => $flavour,
144			@_,
145			parked => 1,
146	root	1.1	);
147	root	1.43
148			_install_std_cb $w, $type;
149
150			# reblessing due to Event being broken
151			bless $w, $class
152	root	1.1	};
153			*{ $flavour } = $coronew;
154			*{"do_$flavour"} = sub {
155			unshift @_, Coro::Event::;
156	root	1.49	next_cancel (&$coronew);
157	root	1.1	};
158			}
159
160	root	1.47	sub Coro::Event::Event::hits { $_[0][3] }
161			sub Coro::Event::Event::got { $_[0][4] }
162	root	1.1
163			=item sweep
164
165			Similar to Event::one_event and Event::sweep: The idle task is called once
166			(this has the effect of jumping back into the Event loop once to serve new
167			events).
168
169			The reason this function exists is that you sometimes want to serve events
170			while doing other work. Calling C<Coro::cede> does not work because
171			C<cede> implies that the current coroutine is runnable and does not call
172			into the Event dispatcher.
173
174			=cut
175
176			sub sweep {
177	root	1.42	Event::one_event 0; # for now
178	root	1.1	}
179
180			=item $result = loop([$timeout])
181
182			This is the version of C<loop> you should use instead of C<Event::loop>
183			when using this module - it will ensure correct scheduling in the presence
184			of events.
185
186			=item unloop([$result])
187
188			Same as Event::unloop (provided here for your convinience only).
189
190			=cut
191
192	root	1.40	$Coro::idle = \&Event::one_event; # inefficient
193	root	1.9
194	root	1.1	1;
195
196	root	1.36	=back
197
198	root	1.1	=head1 AUTHOR
199
200	root	1.27	Marc Lehmann <schmorp@schmorp.de>
201	root	1.25	http://home.schmorp.de/
202	root	1.1
203			=cut
204