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 = 0.05;

@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(&) {
   my $pid = new Coro $_[0];
   $pid->ready;
   $pid;
}

=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 {
   local @_;
   # 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>, L<Coro::Event>.

=head1 AUTHOR

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

=cut

Revision:	1.12
Committed:	Sun Jul 15 15:58:16 2001 UTC (22 years, 10 months ago) by root
Branch:	MAIN
Changes since 1.11:	+2 -1 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	1.12	$VERSION = 0.05;
32	root	1.8
33			@EXPORT = qw(async yield schedule);
34			@EXPORT_OK = qw($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	root	1.11	my $pid = new Coro $_[0];
119			$pid->ready;
120			$pid;
121	root	1.8	}
122	root	1.1
123	root	1.8	=item schedule
124	root	1.6
125	root	1.8	Calls the scheduler. Please note that the current process will not be put
126			into the ready queue, so calling this function usually means you will
127			never be called again.
128	root	1.1
129			=cut
130
131	root	1.8	my $prev;
132
133			sub schedule {
134	root	1.12	local @_;
135	root	1.9	# should be done using priorities :(
136			($prev, $current) = ($current, shift @ready \|\| $idle);
137	root	1.8	Coro::State::transfer($prev, $current);
138	root	1.1	}
139
140	root	1.8	=item yield
141	root	1.1
142	root	1.8	Yield to other processes. This function puts the current process into the
143			ready queue and calls C<schedule>.
144	root	1.7
145	root	1.8	=cut
146
147			sub yield {
148			$current->ready;
149			&schedule;
150			}
151	root	1.7
152	root	1.8	=item terminate
153	root	1.7
154	root	1.8	Terminates the current process.
155	root	1.1
156			=cut
157
158	root	1.8	sub terminate {
159			&schedule;
160	root	1.1	}
161	root	1.6
162	root	1.8	=back
163
164			# dynamic methods
165
166			=head2 PROCESS METHODS
167
168			These are the methods you can call on process objects.
169	root	1.6
170	root	1.8	=over 4
171
172			=item new Coro \⊂
173
174			Create a new process and return it. When the sub returns the process
175			automatically terminates. To start the process you must first put it into
176			the ready queue by calling the ready method.
177	root	1.6
178			=cut
179
180	root	1.8	sub new {
181			my $class = shift;
182			my $proc = $_[0];
183			bless {
184			_coro_state => new Coro::State ($proc ? sub { &$proc; &terminate } : $proc),
185			}, $class;
186			}
187	root	1.6
188	root	1.8	=item $process->ready
189	root	1.1
190	root	1.8	Put the current process into the ready queue.
191	root	1.1
192	root	1.8	=cut
193	root	1.1
194	root	1.8	sub ready {
195			push @ready, $_[0];
196			}
197	root	1.1
198	root	1.8	=back
199	root	1.2
200	root	1.8	=cut
201	root	1.2
202	root	1.8	1;
203	root	1.9
204			=head1 SEE ALSO
205
206			L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
207	root	1.10	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
208	root	1.1
209			=head1 AUTHOR
210
211			Marc Lehmann <pcg@goof.com>
212			http://www.goof.com/pcg/marc/
213
214			=cut
215