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 = 0.09;

@EXPORT = qw(async yield schedule terminate current);
@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, $ref, @attrs) : @attrs;
      };
   }

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

=item $main

This coroutine represents the main program.

=cut

our $main = new Coro;

=item $current (or as function: 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;

sub current() { $current }

=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 { ... } [@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/LIMITATIONS

 - 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.
 - if variables or arguments "disappear" (become undef) or become
   corrupted please contact the author so he cen iron out the
   remaining bugs.
 - this module is not thread-safe. You must only ever use this module from
   the same thread (this requirement might be loosened in the future to
   allow per-thread schedulers, but Coro::Satte does not yet allow this).

=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:	1.19
Committed:	Sat Jul 21 03:44:06 2001 UTC (22 years, 10 months ago) by root
Branch:	MAIN
Changes since 1.18:	+4 -2 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	1.18	$VERSION = 0.09;
37	root	1.8
38	root	1.19	@EXPORT = qw(async yield schedule terminate current);
39	root	1.8	@EXPORT_OK = qw($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	root	1.17	push @attrs, $_;
58	root	1.8	}
59			}
60	root	1.17	return $old ? $old->($package, $ref, @attrs) : @attrs;
61	root	1.8	};
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	root	1.19	=item $current (or as function: current)
78	root	1.1
79	root	1.8	The current coroutine (the last coroutine switched to). The initial value is C<$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	root	1.19
90			sub current() { $current }
91	root	1.9
92			=item $idle
93
94			The coroutine to switch to when no other coroutine is running. The default
95			implementation prints "FATAL: deadlock detected" and exits.
96
97			=cut
98
99			# should be done using priorities :(
100			our $idle = new Coro sub {
101			print STDERR "FATAL: deadlock detected\n";
102			exit(51);
103			};
104	root	1.8
105			# we really need priorities...
106	root	1.16	my @ready; # the ready queue. hehe, rather broken ;)
107	root	1.8
108			# static methods. not really.
109
110			=head2 STATIC METHODS
111
112			Static methods are actually functions that operate on the current process only.
113
114			=over 4
115
116	root	1.13	=item async { ... } [@args...]
117	root	1.8
118			Create a new asynchronous process and return it's process object
119			(usually unused). When the sub returns the new process is automatically
120			terminated.
121
122	root	1.13	# create a new coroutine that just prints its arguments
123			async {
124			print "@_\n";
125			} 1,2,3,4;
126
127			The coderef you submit MUST NOT be a closure that refers to variables
128			in an outer scope. This does NOT work. Pass arguments into it instead.
129
130	root	1.8	=cut
131
132	root	1.13	sub async(&@) {
133			my $pid = new Coro @_;
134	root	1.11	$pid->ready;
135			$pid;
136	root	1.8	}
137	root	1.1
138	root	1.8	=item schedule
139	root	1.6
140	root	1.8	Calls the scheduler. Please note that the current process will not be put
141			into the ready queue, so calling this function usually means you will
142			never be called again.
143	root	1.1
144			=cut
145
146	root	1.8	my $prev;
147
148			sub schedule {
149	root	1.9	# should be done using priorities :(
150			($prev, $current) = ($current, shift @ready \|\| $idle);
151	root	1.8	Coro::State::transfer($prev, $current);
152	root	1.1	}
153
154	root	1.8	=item yield
155	root	1.1
156	root	1.8	Yield to other processes. This function puts the current process into the
157			ready queue and calls C<schedule>.
158	root	1.7
159	root	1.8	=cut
160
161			sub yield {
162			$current->ready;
163			&schedule;
164			}
165	root	1.7
166	root	1.8	=item terminate
167	root	1.7
168	root	1.8	Terminates the current process.
169	root	1.1
170	root	1.13	Future versions of this function will allow result arguments.
171
172	root	1.1	=cut
173
174	root	1.8	sub terminate {
175	root	1.13	$current->{_results} = [@_];
176	root	1.8	&schedule;
177	root	1.1	}
178	root	1.6
179	root	1.8	=back
180
181			# dynamic methods
182
183			=head2 PROCESS METHODS
184
185			These are the methods you can call on process objects.
186	root	1.6
187	root	1.8	=over 4
188
189	root	1.13	=item new Coro \&sub [, @args...]
190	root	1.8
191			Create a new process and return it. When the sub returns the process
192			automatically terminates. To start the process you must first put it into
193			the ready queue by calling the ready method.
194	root	1.6
195	root	1.13	The coderef you submit MUST NOT be a closure that refers to variables
196			in an outer scope. This does NOT work. Pass arguments into it instead.
197
198	root	1.6	=cut
199
200	root	1.13	sub _newcoro {
201			terminate &{+shift};
202			}
203
204	root	1.8	sub new {
205			my $class = shift;
206			bless {
207	root	1.13	_coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
208	root	1.8	}, $class;
209			}
210	root	1.6
211	root	1.8	=item $process->ready
212	root	1.1
213	root	1.8	Put the current process into the ready queue.
214	root	1.1
215	root	1.8	=cut
216	root	1.1
217	root	1.8	sub ready {
218			push @ready, $_[0];
219			}
220	root	1.1
221	root	1.8	=back
222	root	1.2
223	root	1.8	=cut
224	root	1.2
225	root	1.8	1;
226	root	1.14
227	root	1.17	=head1 BUGS/LIMITATIONS
228	root	1.14
229			- could be faster, especially when the core would introduce special
230			support for coroutines (like it does for threads).
231			- there is still a memleak on coroutine termination that I could not
232			identify. Could be as small as a single SV.
233			- this module is not well-tested.
234	root	1.17	- if variables or arguments "disappear" (become undef) or become
235			corrupted please contact the author so he cen iron out the
236			remaining bugs.
237			- this module is not thread-safe. You must only ever use this module from
238			the same thread (this requirement might be loosened in the future to
239			allow per-thread schedulers, but Coro::Satte does not yet allow this).
240	root	1.9
241			=head1 SEE ALSO
242
243			L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
244	root	1.10	L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
245	root	1.1
246			=head1 AUTHOR
247
248			Marc Lehmann <pcg@goof.com>
249			http://www.goof.com/pcg/marc/
250
251			=cut
252