ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/Coro/Coro.pm
(Generate patch)

Comparing Coro/Coro.pm (file contents):
Revision 1.1 by root, Tue Jul 3 02:53:34 2001 UTC vs.
Revision 1.20 by root, Sat Jul 21 18:21:45 2001 UTC

1=head1 NAME 1=head1 NAME
2 2
3Coro - create an manage coroutines 3Coro - coroutine process abstraction
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use Coro; 7 use Coro;
8 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
9=head1 DESCRIPTION 21=head1 DESCRIPTION
10 22
23This module collection manages coroutines. Coroutines are similar to
24Threads but don't run in parallel.
25
26This module is still experimental, see the BUGS section below.
27
28In this module, coroutines are defined as "callchain + lexical variables
29+ @_ + $_ + $@ + $^W), that is, a coroutine has it's own callchain, it's
30own set of lexicals and it's own set of perl's most important global
31variables.
32
33=cut
34
35package Coro;
36
37use Coro::State;
38
39use base Exporter;
40
41$VERSION = 0.10;
42
43@EXPORT = qw(async yield schedule terminate current);
44@EXPORT_OK = qw($current);
45
46{
47 my @async;
48
49 # this way of handling attributes simply is NOT scalable ;()
50 sub import {
51 Coro->export_to_level(1, @_);
52 my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE};
53 *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub {
54 my ($package, $ref) = (shift, shift);
55 my @attrs;
56 for (@_) {
57 if ($_ eq "Coro") {
58 push @async, $ref;
59 } else {
60 push @attrs, $_;
61 }
62 }
63 return $old ? $old->($package, $ref, @attrs) : @attrs;
64 };
65 }
66
67 sub INIT {
68 &async(pop @async) while @async;
69 }
70}
71
72=item $main
73
74This coroutine represents the main program.
75
76=cut
77
78our $main = new Coro;
79
80=item $current (or as function: current)
81
82The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
83
84=cut
85
86# maybe some other module used Coro::Specific before...
87if ($current) {
88 $main->{specific} = $current->{specific};
89}
90
91our $current = $main;
92
93sub current() { $current }
94
95=item $idle
96
97The coroutine to switch to when no other coroutine is running. The default
98implementation prints "FATAL: deadlock detected" and exits.
99
100=cut
101
102# should be done using priorities :(
103our $idle = new Coro sub {
104 print STDERR "FATAL: deadlock detected\n";
105 exit(51);
106};
107
108# we really need priorities...
109my @ready; # the ready queue. hehe, rather broken ;)
110
111# static methods. not really.
112
113=head2 STATIC METHODS
114
115Static methods are actually functions that operate on the current process only.
116
11=over 4 117=over 4
12 118
13=cut 119=item async { ... } [@args...]
14 120
15package Coro; 121Create a new asynchronous process and return it's process object
122(usually unused). When the sub returns the new process is automatically
123terminated.
16 124
17BEGIN { 125 # create a new coroutine that just prints its arguments
18 $VERSION = 0.01; 126 async {
127 print "@_\n";
128 } 1,2,3,4;
19 129
20 require XSLoader; 130The coderef you submit MUST NOT be a closure that refers to variables
21 XSLoader::load Coro, $VERSION; 131in an outer scope. This does NOT work. Pass arguments into it instead.
22}
23 132
24=item $main
25
26This coroutine represents the main program.
27
28=item $current
29
30The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course).
31
32=cut 133=cut
33 134
34$main = $current = _newprocess { 135sub async(&@) {
35 # never being called 136 my $pid = new Coro @_;
36}; 137 $pid->ready;
138 $pid;
139}
37 140
38=item $error, $error_msg, $error_coro 141=item schedule
39 142
40This coroutine will be called on fatal errors. C<$error_msg> and 143Calls the scheduler. Please note that the current process will not be put
41C<$error_coro> return the error message and the error-causing coroutine, 144into the ready queue, so calling this function usually means you will
42respectively. 145never be called again.
43 146
44=cut 147=cut
45 148
46$error_msg = 149my $prev;
47$error_coro = undef;
48 150
49$error = _newprocess { 151sub schedule {
50 print STDERR "FATAL: $error_msg, program aborted\n"; 152 # should be done using priorities :(
51 exit 250; 153 ($prev, $current) = ($current, shift @ready || $idle);
52}; 154 Coro::State::transfer($prev, $current);
155}
53 156
54=item $coro = new $coderef [, @args] 157=item yield
55 158
56Create a new coroutine and return it. The first C<resume> call to this 159Yield to other processes. This function puts the current process into the
57coroutine will start execution at the given coderef. If it returns it 160ready queue and calls C<schedule>.
58should return a coroutine to switch to. If, after returning, the coroutine
59is C<resume>d again it starts execution again at the givne coderef.
60 161
61=cut 162=cut
163
164sub yield {
165 $current->ready;
166 &schedule;
167}
168
169=item terminate
170
171Terminates the current process.
172
173Future versions of this function will allow result arguments.
174
175=cut
176
177sub terminate {
178 $current->{_results} = [@_];
179 &schedule;
180}
181
182=back
183
184# dynamic methods
185
186=head2 PROCESS METHODS
187
188These are the methods you can call on process objects.
189
190=over 4
191
192=item new Coro \&sub [, @args...]
193
194Create a new process and return it. When the sub returns the process
195automatically terminates. To start the process you must first put it into
196the ready queue by calling the ready method.
197
198The coderef you submit MUST NOT be a closure that refers to variables
199in an outer scope. This does NOT work. Pass arguments into it instead.
200
201=cut
202
203sub _newcoro {
204 terminate &{+shift};
205}
62 206
63sub new { 207sub new {
64 my $class = $_[0]; 208 my $class = shift;
65 my $proc = $_[1]; 209 bless {
66 bless _newprocess { 210 _coro_state => (new Coro::State $_[0] && \&_newcoro, @_),
67 do {
68 eval { &$proc->resume };
69 if ($@) {
70 ($error_msg, $error_coro) = ($@, $current);
71 $error->resume;
72 }
73 } while ();
74 }, $class; 211 }, $class;
75} 212}
76 213
77=item $coro->resume 214=item $process->ready
78 215
79Resume execution at the given coroutine. 216Put the current process into the ready queue.
80 217
81=cut 218=cut
82 219
83my $prev; 220sub ready {
84 221 push @ready, $_[0];
85sub resume {
86 $prev = $current; $current = $_[0];
87 _transfer($prev, $current);
88} 222}
223
224=back
225
226=cut
89 227
901; 2281;
91 229
92=back 230=head1 BUGS/LIMITATIONS
93 231
94=head1 BUGS 232 - could be faster, especially when the core would introduce special
233 support for coroutines (like it does for threads).
234 - there is still a memleak on coroutine termination that I could not
235 identify. Could be as small as a single SV.
236 - this module is not well-tested.
237 - if variables or arguments "disappear" (become undef) or become
238 corrupted please contact the author so he cen iron out the
239 remaining bugs.
240 - this module is not thread-safe. You must only ever use this module from
241 the same thread (this requirement might be loosened in the future to
242 allow per-thread schedulers, but Coro::State does not yet allow this).
95 243
96This module has not yet been extensively tested. 244=head1 SEE ALSO
245
246L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>,
247L<Coro::Signal>, L<Coro::State>, L<Coro::Event>.
97 248
98=head1 AUTHOR 249=head1 AUTHOR
99 250
100 Marc Lehmann <pcg@goof.com> 251 Marc Lehmann <pcg@goof.com>
101 http://www.goof.com/pcg/marc/ 252 http://www.goof.com/pcg/marc/

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines