1 |
=head1 NAME |
2 |
|
3 |
Coro - coroutine process abstraction |
4 |
|
5 |
=head1 SYNOPSIS |
6 |
|
7 |
use Coro; |
8 |
|
9 |
async { |
10 |
# some asynchronous thread of execution |
11 |
}; |
12 |
|
13 |
# alternatively create an async process like this: |
14 |
|
15 |
sub some_func : Coro { |
16 |
# some more async code |
17 |
} |
18 |
|
19 |
yield; |
20 |
|
21 |
=head1 DESCRIPTION |
22 |
|
23 |
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 |
=cut |
29 |
|
30 |
package Coro; |
31 |
|
32 |
use Coro::State; |
33 |
|
34 |
use base Exporter; |
35 |
|
36 |
$VERSION = 0.09; |
37 |
|
38 |
@EXPORT = qw(async yield schedule terminate current); |
39 |
@EXPORT_OK = qw($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, $ref, @attrs) : @attrs; |
61 |
}; |
62 |
} |
63 |
|
64 |
sub INIT { |
65 |
async pop @async while @async; |
66 |
} |
67 |
} |
68 |
|
69 |
=item $main |
70 |
|
71 |
This coroutine represents the main program. |
72 |
|
73 |
=cut |
74 |
|
75 |
our $main = new Coro; |
76 |
|
77 |
=item $current (or as function: current) |
78 |
|
79 |
The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
80 |
|
81 |
=cut |
82 |
|
83 |
# maybe some other module used Coro::Specific before... |
84 |
if ($current) { |
85 |
$main->{specific} = $current->{specific}; |
86 |
} |
87 |
|
88 |
our $current = $main; |
89 |
|
90 |
sub current() { $current } |
91 |
|
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 |
|
105 |
# we really need priorities... |
106 |
my @ready; # the ready queue. hehe, rather broken ;) |
107 |
|
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 |
=item async { ... } [@args...] |
117 |
|
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 |
# 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 |
=cut |
131 |
|
132 |
sub async(&@) { |
133 |
my $pid = new Coro @_; |
134 |
$pid->ready; |
135 |
$pid; |
136 |
} |
137 |
|
138 |
=item schedule |
139 |
|
140 |
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 |
|
144 |
=cut |
145 |
|
146 |
my $prev; |
147 |
|
148 |
sub schedule { |
149 |
# should be done using priorities :( |
150 |
($prev, $current) = ($current, shift @ready || $idle); |
151 |
Coro::State::transfer($prev, $current); |
152 |
} |
153 |
|
154 |
=item yield |
155 |
|
156 |
Yield to other processes. This function puts the current process into the |
157 |
ready queue and calls C<schedule>. |
158 |
|
159 |
=cut |
160 |
|
161 |
sub yield { |
162 |
$current->ready; |
163 |
&schedule; |
164 |
} |
165 |
|
166 |
=item terminate |
167 |
|
168 |
Terminates the current process. |
169 |
|
170 |
Future versions of this function will allow result arguments. |
171 |
|
172 |
=cut |
173 |
|
174 |
sub terminate { |
175 |
$current->{_results} = [@_]; |
176 |
&schedule; |
177 |
} |
178 |
|
179 |
=back |
180 |
|
181 |
# dynamic methods |
182 |
|
183 |
=head2 PROCESS METHODS |
184 |
|
185 |
These are the methods you can call on process objects. |
186 |
|
187 |
=over 4 |
188 |
|
189 |
=item new Coro \&sub [, @args...] |
190 |
|
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 |
|
195 |
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 |
=cut |
199 |
|
200 |
sub _newcoro { |
201 |
terminate &{+shift}; |
202 |
} |
203 |
|
204 |
sub new { |
205 |
my $class = shift; |
206 |
bless { |
207 |
_coro_state => (new Coro::State $_[0] && \&_newcoro, @_), |
208 |
}, $class; |
209 |
} |
210 |
|
211 |
=item $process->ready |
212 |
|
213 |
Put the current process into the ready queue. |
214 |
|
215 |
=cut |
216 |
|
217 |
sub ready { |
218 |
push @ready, $_[0]; |
219 |
} |
220 |
|
221 |
=back |
222 |
|
223 |
=cut |
224 |
|
225 |
1; |
226 |
|
227 |
=head1 BUGS/LIMITATIONS |
228 |
|
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 |
- 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 |
|
241 |
=head1 SEE ALSO |
242 |
|
243 |
L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
244 |
L<Coro::Signal>, L<Coro::State>, L<Coro::Event>. |
245 |
|
246 |
=head1 AUTHOR |
247 |
|
248 |
Marc Lehmann <pcg@goof.com> |
249 |
http://www.goof.com/pcg/marc/ |
250 |
|
251 |
=cut |
252 |
|