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

This module collection manages coroutines. Coroutines are similar to
Threads but don't run in parallel.

This module is still experimental, see the BUGS section below.

=cut

package Coro;

use Coro::State;

use base Exporter;

$VERSION = 0.05;

@EXPORT = qw(async yield schedule terminate);
@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; #d#
our @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 { ... } [@args...]

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

   # create a new coroutine that just prints its arguments
   async {
      print "@_\n";
   } 1,2,3,4;

The coderef you submit MUST NOT be a closure that refers to variables
in an outer scope. This does NOT work. Pass arguments into it instead.

=cut

sub async(&@) {
   my $pid = new Coro @_;
   $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 {
   # 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.

Future versions of this function will allow result arguments.

=cut

sub terminate {
   $current->{_results} = [@_];
   &schedule;
}

=back

# dynamic methods

=head2 PROCESS METHODS

These are the methods you can call on process objects.

=over 4

=item new Coro \&sub [, @args...]

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.

The coderef you submit MUST NOT be a closure that refers to variables
in an outer scope. This does NOT work. Pass arguments into it instead.

=cut

sub _newcoro {
   terminate &{+shift};
}

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

=item $process->ready

Put the current process into the ready queue.

=cut

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

=back

=cut

1;

=head1 BUGS

 - could be faster, especially when the core would introduce special
   support for coroutines (like it does for threads).
 - there is still a memleak on coroutine termination that I could not
   identify. Could be as small as a single SV.
 - this module is not well-tested.

=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:	1.14
Committed:	Tue Jul 17 02:21:56 2001 UTC (22 years, 10 months ago) by root
Branch:	MAIN
Changes since 1.13:	+13 -0 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	1.14	This module collection manages coroutines. Coroutines are similar to
24			Threads but don't run in parallel.
25
26			This module is still experimental, see the BUGS section below.
27
28	root	1.8	=cut
29
30			package Coro;
31
32			use Coro::State;
33
34			use base Exporter;
35
36	root	1.12	$VERSION = 0.05;
37	root	1.8
38	root	1.13	@EXPORT = qw(async yield schedule terminate);
39	root	1.8	@EXPORT_OK = qw($current);
40
41			{
42			use subs 'async';
43
44			my @async;
45
46			# this way of handling attributes simply is NOT scalable ;()
47			sub import {
48			Coro->export_to_level(1, @_);
49			my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
50			*{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
51			my ($package, $ref) = (shift, shift);
52			my @attrs;
53			for (@_) {
54			if ($_ eq "Coro") {
55			push @async, $ref;
56			} else {
57			push @attrs, @_;
58			}
59			}
60			return $old ? $old->($package, $name, @attrs) : @attrs;
61			};
62			}
63
64			sub INIT {
65			async pop @async while @async;
66			}
67			}
68
69			=item $main
70	root	1.2
71	root	1.8	This coroutine represents the main program.
72	root	1.1
73			=cut
74
75	root	1.9	our $main = new Coro;
76	root	1.8
77			=item $current
78	root	1.1
79	root	1.8	The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
80	root	1.1
81	root	1.8	=cut
82
83			# maybe some other module used Coro::Specific before...
84			if ($current) {
85			$main->{specific} = $current->{specific};
86	root	1.1	}
87
88	root	1.9	our $current = $main;
89
90			=item $idle
91
92			The coroutine to switch to when no other coroutine is running. The default
93			implementation prints "FATAL: deadlock detected" and exits.
94
95			=cut
96
97			# should be done using priorities :(
98			our $idle = new Coro sub {
99			print STDERR "FATAL: deadlock detected\n";
100			exit(51);
101			};
102	root	1.8
103			# we really need priorities...
104	root	1.13	## my @ready; #d#
105			our @ready = (); # the ready queue. hehe, rather broken ;)
106	root	1.8
107			# static methods. not really.
108
109			=head2 STATIC METHODS
110
111			Static methods are actually functions that operate on the current process only.
112
113			=over 4
114
115	root	1.13	=item async { ... } [@args...]
116	root	1.8
117			Create a new asynchronous process and return it's process object
118			(usually unused). When the sub returns the new process is automatically
119			terminated.
120
121	root	1.13	# create a new coroutine that just prints its arguments
122			async {
123			print "@_\n";
124			} 1,2,3,4;
125
126			The coderef you submit MUST NOT be a closure that refers to variables
127			in an outer scope. This does NOT work. Pass arguments into it instead.
128
129	root	1.8	=cut
130
131	root	1.13	sub async(&@) {
132			my $pid = new Coro @_;
133	root	1.11	$pid->ready;
134			$pid;
135	root	1.8	}
136	root	1.1
137	root	1.8	=item schedule
138	root	1.6
139	root	1.8	Calls the scheduler. Please note that the current process will not be put
140			into the ready queue, so calling this function usually means you will
141			never be called again.
142	root	1.1
143			=cut
144
145	root	1.8	my $prev;
146
147			sub schedule {
148	root	1.9	# should be done using priorities :(
149			($prev, $current) = ($current, shift @ready \|\| $idle);
150	root	1.8	Coro::State::transfer($prev, $current);
151	root	1.1	}
152
153	root	1.8	=item yield
154	root	1.1
155	root	1.8	Yield to other processes. This function puts the current process into the
156			ready queue and calls C<schedule>.
157	root	1.7
158	root	1.8	=cut
159
160			sub yield {
161			$current->ready;
162			&schedule;
163			}
164	root	1.7
165	root	1.8	=item terminate
166	root	1.7
167	root	1.8	Terminates the current process.
168	root	1.1
169	root	1.13	Future versions of this function will allow result arguments.
170
171	root	1.1	=cut
172
173	root	1.8	sub terminate {
174	root	1.13	$current->{_results} = [@_];
175	root	1.8	&schedule;
176	root	1.1	}
177	root	1.6
178	root	1.8	=back
179
180			# dynamic methods
181
182			=head2 PROCESS METHODS
183
184			These are the methods you can call on process objects.
185	root	1.6
186	root	1.8	=over 4
187
188	root	1.13	=item new Coro \&sub [, @args...]
189	root	1.8
190			Create a new process and return it. When the sub returns the process
191			automatically terminates. To start the process you must first put it into
192			the ready queue by calling the ready method.
193	root	1.6
194	root	1.13	The coderef you submit MUST NOT be a closure that refers to variables
195			in an outer scope. This does NOT work. Pass arguments into it instead.
196
197	root	1.6	=cut
198
199	root	1.13	sub _newcoro {
200			terminate &{+shift};
201			}
202
203	root	1.8	sub new {
204			my $class = shift;
205			bless {
206	root	1.13	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
207	root	1.8	}, $class;
208			}
209	root	1.6
210	root	1.8	=item $process->ready
211	root	1.1
212	root	1.8	Put the current process into the ready queue.
213	root	1.1
214	root	1.8	=cut
215	root	1.1
216	root	1.8	sub ready {
217			push @ready, $_[0];
218			}
219	root	1.1
220	root	1.8	=back
221	root	1.2
222	root	1.8	=cut
223	root	1.2
224	root	1.8	1;
225	root	1.14
226			=head1 BUGS
227
228			- could be faster, especially when the core would introduce special
229			support for coroutines (like it does for threads).
230			- there is still a memleak on coroutine termination that I could not
231			identify. Could be as small as a single SV.
232			- this module is not well-tested.
233	root	1.9
234			=head1 SEE ALSO
235
236			L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
237	root	1.10	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
238	root	1.1
239			=head1 AUTHOR
240
241			Marc Lehmann <pcg@goof.com>
242			http://www.goof.com/pcg/marc/
243
244			=cut
245