Coro/Coro.pm

=head1 NAME

Coro - coroutine process abstraction

=head1 SYNOPSIS

 use Coro;

 async {
    # some asynchronous thread of execution
 };

 # alternatively create an async process like this:

 sub some_func : Coro {
    # some more async code
 }

 yield;

=head1 DESCRIPTION

=cut

package Coro;

use Coro::State;

use base Exporter;

$VERSION = 0.04;

@EXPORT = qw(async yield schedule);
@EXPORT_OK = qw($current);

{
   use subs 'async';

   my @async;

   # this way of handling attributes simply is NOT scalable ;()
   sub import {
      Coro->export_to_level(1, @_);
      my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
      *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
         my ($package, $ref) = (shift, shift);
         my @attrs;
         for (@_) {
            if ($_ eq "Coro") {
               push @async, $ref;
            } else {
               push @attrs, @_;
            }
         }
         return $old ? $old->($package, $name, @attrs) : @attrs;
      };
   }

   sub INIT {
      async pop @async while @async;
   }
}

=item $main

This coroutine represents the main program.

=cut

our $main = new Coro;

=item $current

The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).

=cut

# maybe some other module used Coro::Specific before...
if ($current) {
   $main->{specific} = $current->{specific};
}

our $current = $main;

=item $idle

The coroutine to switch to when no other coroutine is running. The default
implementation prints "FATAL: deadlock detected" and exits.

=cut

# should be done using priorities :(
our $idle = new Coro sub {
   print STDERR "FATAL: deadlock detected\n";
   exit(51);
};

# we really need priorities...
my @ready = (); # the ready queue. hehe, rather broken ;)

# static methods. not really.

=head2 STATIC METHODS

Static methods are actually functions that operate on the current process only.

=over 4

=item async { ... };

Create a new asynchronous process and return it's process object
(usually unused). When the sub returns the new process is automatically
terminated.

=cut

sub async(&) {
   (new Coro $_[0])->ready;
}

=item schedule

Calls the scheduler. Please note that the current process will not be put
into the ready queue, so calling this function usually means you will
never be called again.

=cut

my $prev;

sub schedule {
   # should be done using priorities :(
   ($prev, $current) = ($current, shift @ready || $idle);
   Coro::State::transfer($prev, $current);
}

=item yield

Yield to other processes. This function puts the current process into the
ready queue and calls C<schedule>.

=cut

sub yield {
   $current->ready;
   &schedule;
}

=item terminate

Terminates the current process.

=cut

sub terminate {
   &schedule;
}

=back

# dynamic methods

=head2 PROCESS METHODS

These are the methods you can call on process objects.

=over 4

=item new Coro \&sub;

Create a new process and return it. When the sub returns the process
automatically terminates. To start the process you must first put it into
the ready queue by calling the ready method.

=cut

sub new {
   my $class = shift;
   my $proc = $_[0];
   bless {
      _coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc),
   }, $class;
}

=item $process->ready

Put the current process into the ready queue.

=cut

sub ready {
   push @ready, $_[0];
}

=back

=cut

1;

=head1 SEE ALSO

L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
L<Coro::Signal>, L<Coro::State>.

=head1 AUTHOR

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

=cut

Revision:	1.9
Committed:	Sun Jul 15 02:35:52 2001 UTC (22 years, 10 months ago) by root
Branch:	MAIN
Changes since 1.8:	+23 -8 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3	root	1.8	Coro - coroutine process abstraction
4	root	1.1
5			=head1 SYNOPSIS
6
7			use Coro;
8
9	root	1.8	async {
10			# some asynchronous thread of execution
11	root	1.2	};
12
13	root	1.8	# alternatively create an async process like this:
14	root	1.6
15	root	1.8	sub some_func : Coro {
16			# some more async code
17			}
18
19			yield;
20	root	1.2
21	root	1.1	=head1 DESCRIPTION
22
23	root	1.8	=cut
24
25			package Coro;
26
27			use Coro::State;
28
29			use base Exporter;
30
31	root	1.9	$VERSION = 0.04;
32	root	1.8
33			@EXPORT = qw(async yield schedule);
34			@EXPORT_OK = qw($current);
35
36			{
37			use subs 'async';
38
39			my @async;
40
41			# this way of handling attributes simply is NOT scalable ;()
42			sub import {
43			Coro->export_to_level(1, @_);
44			my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
45			*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
46			my ($package, $ref) = (shift, shift);
47			my @attrs;
48			for (@_) {
49			if ($_ eq "Coro") {
50			push @async, $ref;
51			} else {
52			push @attrs, @_;
53			}
54			}
55			return $old ? $old->($package, $name, @attrs) : @attrs;
56			};
57			}
58
59			sub INIT {
60			async pop @async while @async;
61			}
62			}
63
64			=item $main
65	root	1.2
66	root	1.8	This coroutine represents the main program.
67	root	1.1
68			=cut
69
70	root	1.9	our $main = new Coro;
71	root	1.8
72			=item $current
73	root	1.1
74	root	1.8	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
75	root	1.1
76	root	1.8	=cut
77
78			# maybe some other module used Coro::Specific before...
79			if ($current) {
80			$main->{specific} = $current->{specific};
81	root	1.1	}
82
83	root	1.9	our $current = $main;
84
85			=item $idle
86
87			The coroutine to switch to when no other coroutine is running. The default
88			implementation prints "FATAL: deadlock detected" and exits.
89
90			=cut
91
92			# should be done using priorities :(
93			our $idle = new Coro sub {
94			print STDERR "FATAL: deadlock detected\n";
95			exit(51);
96			};
97	root	1.8
98			# we really need priorities...
99			my @ready = (); # the ready queue. hehe, rather broken ;)
100
101			# static methods. not really.
102
103			=head2 STATIC METHODS
104
105			Static methods are actually functions that operate on the current process only.
106
107			=over 4
108
109			=item async { ... };
110
111			Create a new asynchronous process and return it's process object
112			(usually unused). When the sub returns the new process is automatically
113			terminated.
114
115			=cut
116
117			sub async(&) {
118			(new Coro $_[0])->ready;
119			}
120	root	1.1
121	root	1.8	=item schedule
122	root	1.6
123	root	1.8	Calls the scheduler. Please note that the current process will not be put
124			into the ready queue, so calling this function usually means you will
125			never be called again.
126	root	1.1
127			=cut
128
129	root	1.8	my $prev;
130
131			sub schedule {
132	root	1.9	# should be done using priorities :(
133			($prev, $current) = ($current, shift @ready \|\| $idle);
134	root	1.8	Coro::State::transfer($prev, $current);
135	root	1.1	}
136
137	root	1.8	=item yield
138	root	1.1
139	root	1.8	Yield to other processes. This function puts the current process into the
140			ready queue and calls C<schedule>.
141	root	1.7
142	root	1.8	=cut
143
144			sub yield {
145			$current->ready;
146			&schedule;
147			}
148	root	1.7
149	root	1.8	=item terminate
150	root	1.7
151	root	1.8	Terminates the current process.
152	root	1.1
153			=cut
154
155	root	1.8	sub terminate {
156			&schedule;
157	root	1.1	}
158	root	1.6
159	root	1.8	=back
160
161			# dynamic methods
162
163			=head2 PROCESS METHODS
164
165			These are the methods you can call on process objects.
166	root	1.6
167	root	1.8	=over 4
168
169			=item new Coro \⊂
170
171			Create a new process and return it. When the sub returns the process
172			automatically terminates. To start the process you must first put it into
173			the ready queue by calling the ready method.
174	root	1.6
175			=cut
176
177	root	1.8	sub new {
178			my $class = shift;
179			my $proc = $_[0];
180			bless {
181			_coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc),
182			}, $class;
183			}
184	root	1.6
185	root	1.8	=item $process->ready
186	root	1.1
187	root	1.8	Put the current process into the ready queue.
188	root	1.1
189	root	1.8	=cut
190	root	1.1
191	root	1.8	sub ready {
192			push @ready, $_[0];
193			}
194	root	1.1
195	root	1.8	=back
196	root	1.2
197	root	1.8	=cut
198	root	1.2
199	root	1.8	1;
200	root	1.9
201			=head1 SEE ALSO
202
203			L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
204			L<Coro::Signal>, L<Coro::State>.
205	root	1.1
206			=head1 AUTHOR
207
208			Marc Lehmann <pcg@goof.com>
209			http://www.goof.com/pcg/marc/
210
211			=cut
212