… | |
… | |
19 | cede; |
19 | cede; |
20 | |
20 | |
21 | =head1 DESCRIPTION |
21 | =head1 DESCRIPTION |
22 | |
22 | |
23 | This module collection manages coroutines. Coroutines are similar to |
23 | This module collection manages coroutines. Coroutines are similar to |
24 | Threads but don't run in parallel. |
24 | threads but don't run in parallel. |
25 | |
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26 | This module is still experimental, see the BUGS section below. |
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27 | |
25 | |
28 | In this module, coroutines are defined as "callchain + lexical variables |
26 | In this module, coroutines are defined as "callchain + lexical variables |
29 | + @_ + $_ + $@ + $^W), that is, a coroutine has it's own callchain, it's |
27 | + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own |
30 | own set of lexicals and it's own set of perl's most important global |
28 | callchain, it's own set of lexicals and it's own set of perl's most |
31 | variables. |
29 | important global variables. |
32 | |
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33 | WARNING: When using this module, make sure that, at program end, no |
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34 | coroutines are still running OR just call exit before falling off the |
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35 | end. The reason for this is that some coroutine of yours might have called |
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36 | into a C function, and falling off the end of main:: results in returning |
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37 | to that C function instead if to the main C interpreter. |
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38 | |
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39 | WARNING: Unless you really know what you are doing, do NOT do context |
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40 | switches inside callbacks from the XS level. The reason for this is |
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41 | similar to the reason above: A callback calls a perl function, this |
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42 | perl function does a context switch, some other callback is called, the |
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43 | original function returns from it - to what? To the wrong XS function, |
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44 | with totally different return values. Unfortunately, this includes |
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45 | callbacks done by perl itself (tie'd variables!). |
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46 | |
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47 | The only workaround for this is to do coroutines on C level. |
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48 | |
30 | |
49 | =cut |
31 | =cut |
50 | |
32 | |
51 | package Coro; |
33 | package Coro; |
52 | |
34 | |
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35 | BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") } |
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36 | |
53 | use Coro::State; |
37 | use Coro::State; |
54 | |
38 | |
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39 | use vars qw($idle $main $current); |
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40 | |
55 | use base Exporter; |
41 | use base Exporter; |
56 | |
42 | |
57 | $VERSION = 0.10; |
43 | $VERSION = '1.4'; |
58 | |
44 | |
59 | @EXPORT = qw(async cede schedule terminate current); |
45 | @EXPORT = qw(async cede schedule terminate current); |
60 | @EXPORT_OK = qw($current); |
46 | %EXPORT_TAGS = ( |
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47 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
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48 | ); |
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49 | @EXPORT_OK = @{$EXPORT_TAGS{prio}}; |
61 | |
50 | |
62 | { |
51 | { |
63 | my @async; |
52 | my @async; |
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53 | my $init; |
64 | |
54 | |
65 | # this way of handling attributes simply is NOT scalable ;() |
55 | # this way of handling attributes simply is NOT scalable ;() |
66 | sub import { |
56 | sub import { |
67 | Coro->export_to_level(1, @_); |
57 | Coro->export_to_level(1, @_); |
68 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
58 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
… | |
… | |
70 | my ($package, $ref) = (shift, shift); |
60 | my ($package, $ref) = (shift, shift); |
71 | my @attrs; |
61 | my @attrs; |
72 | for (@_) { |
62 | for (@_) { |
73 | if ($_ eq "Coro") { |
63 | if ($_ eq "Coro") { |
74 | push @async, $ref; |
64 | push @async, $ref; |
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65 | unless ($init++) { |
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66 | eval q{ |
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67 | sub INIT { |
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68 | &async(pop @async) while @async; |
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69 | } |
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70 | }; |
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71 | } |
75 | } else { |
72 | } else { |
76 | push @attrs, $_; |
73 | push @attrs, $_; |
77 | } |
74 | } |
78 | } |
75 | } |
79 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
76 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
80 | }; |
77 | }; |
81 | } |
78 | } |
82 | |
79 | |
83 | sub INIT { |
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84 | &async(pop @async) while @async; |
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85 | } |
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86 | } |
80 | } |
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81 | |
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82 | =over 4 |
87 | |
83 | |
88 | =item $main |
84 | =item $main |
89 | |
85 | |
90 | This coroutine represents the main program. |
86 | This coroutine represents the main program. |
91 | |
87 | |
92 | =cut |
88 | =cut |
93 | |
89 | |
94 | our $main = new Coro; |
90 | $main = new Coro; |
95 | |
91 | |
96 | =item $current (or as function: current) |
92 | =item $current (or as function: current) |
97 | |
93 | |
98 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
94 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
99 | |
95 | |
… | |
… | |
102 | # maybe some other module used Coro::Specific before... |
98 | # maybe some other module used Coro::Specific before... |
103 | if ($current) { |
99 | if ($current) { |
104 | $main->{specific} = $current->{specific}; |
100 | $main->{specific} = $current->{specific}; |
105 | } |
101 | } |
106 | |
102 | |
107 | our $current = $main; |
103 | $current = $main; |
108 | |
104 | |
109 | sub current() { $current } |
105 | sub current() { $current } |
110 | |
106 | |
111 | =item $idle |
107 | =item $idle |
112 | |
108 | |
… | |
… | |
114 | implementation prints "FATAL: deadlock detected" and exits. |
110 | implementation prints "FATAL: deadlock detected" and exits. |
115 | |
111 | |
116 | =cut |
112 | =cut |
117 | |
113 | |
118 | # should be done using priorities :( |
114 | # should be done using priorities :( |
119 | our $idle = new Coro sub { |
115 | $idle = new Coro sub { |
120 | print STDERR "FATAL: deadlock detected\n"; |
116 | print STDERR "FATAL: deadlock detected\n"; |
121 | exit(51); |
117 | exit(51); |
122 | }; |
118 | }; |
123 | |
119 | |
124 | # we really need priorities... |
120 | # this coroutine is necessary because a coroutine |
125 | my @ready; # the ready queue. hehe, rather broken ;) |
121 | # cannot destroy itself. |
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122 | my @destroy; |
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123 | my $manager; |
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124 | $manager = new Coro sub { |
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125 | while () { |
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126 | # by overwriting the state object with the manager we destroy it |
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127 | # while still being able to schedule this coroutine (in case it has |
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128 | # been readied multiple times. this is harmless since the manager |
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129 | # can be called as many times as neccessary and will always |
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130 | # remove itself from the runqueue |
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131 | while (@destroy) { |
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132 | my $coro = pop @destroy; |
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133 | $coro->{status} ||= []; |
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134 | $_->ready for @{delete $coro->{join} || []}; |
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135 | |
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136 | # the next line destroys the _coro_state, but keeps the |
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137 | # process itself intact (we basically make it a zombie |
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138 | # process that always runs the manager thread, so it's possible |
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139 | # to transfer() to this process). |
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140 | $coro->{_coro_state} = $manager->{_coro_state}; |
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141 | } |
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142 | &schedule; |
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143 | } |
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144 | }; |
126 | |
145 | |
127 | # static methods. not really. |
146 | # static methods. not really. |
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147 | |
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148 | =back |
128 | |
149 | |
129 | =head2 STATIC METHODS |
150 | =head2 STATIC METHODS |
130 | |
151 | |
131 | Static methods are actually functions that operate on the current process only. |
152 | Static methods are actually functions that operate on the current process only. |
132 | |
153 | |
… | |
… | |
141 | # create a new coroutine that just prints its arguments |
162 | # create a new coroutine that just prints its arguments |
142 | async { |
163 | async { |
143 | print "@_\n"; |
164 | print "@_\n"; |
144 | } 1,2,3,4; |
165 | } 1,2,3,4; |
145 | |
166 | |
146 | The coderef you submit MUST NOT be a closure that refers to variables |
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147 | in an outer scope. This does NOT work. Pass arguments into it instead. |
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148 | |
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149 | =cut |
167 | =cut |
150 | |
168 | |
151 | sub async(&@) { |
169 | sub async(&@) { |
152 | my $pid = new Coro @_; |
170 | my $pid = new Coro @_; |
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171 | $manager->ready; # this ensures that the stack is cloned from the manager |
153 | $pid->ready; |
172 | $pid->ready; |
154 | $pid; |
173 | $pid; |
155 | } |
174 | } |
156 | |
175 | |
157 | =item schedule |
176 | =item schedule |
… | |
… | |
160 | into the ready queue, so calling this function usually means you will |
179 | into the ready queue, so calling this function usually means you will |
161 | never be called again. |
180 | never be called again. |
162 | |
181 | |
163 | =cut |
182 | =cut |
164 | |
183 | |
165 | my $prev; |
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166 | |
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167 | sub schedule { |
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168 | # should be done using priorities :( |
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169 | ($prev, $current) = ($current, shift @ready || $idle); |
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170 | Coro::State::transfer($prev, $current); |
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171 | } |
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172 | |
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173 | =item cede |
184 | =item cede |
174 | |
185 | |
175 | "Cede" to other processes. This function puts the current process into the |
186 | "Cede" to other processes. This function puts the current process into the |
176 | ready queue and calls C<schedule>, which has the effect of giving up the |
187 | ready queue and calls C<schedule>, which has the effect of giving up the |
177 | current "timeslice" to other coroutines of the same or higher priority. |
188 | current "timeslice" to other coroutines of the same or higher priority. |
178 | |
189 | |
179 | =cut |
190 | =cut |
180 | |
191 | |
181 | sub cede { |
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182 | $current->ready; |
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183 | &schedule; |
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184 | } |
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185 | |
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186 | =item terminate |
192 | =item terminate [arg...] |
187 | |
193 | |
188 | Terminates the current process. |
194 | Terminates the current process with the given status values (see L<cancel>). |
189 | |
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190 | Future versions of this function will allow result arguments. |
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191 | |
195 | |
192 | =cut |
196 | =cut |
193 | |
197 | |
194 | sub terminate { |
198 | sub terminate { |
195 | my $self = $current; |
199 | $current->cancel (@_); |
196 | $self->{_results} = [@_]; |
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197 | $current = shift @ready || $idle; |
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198 | Coro::State::transfer(delete $self->{_coro_state}, $current); |
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199 | # cannot return |
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200 | die; |
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201 | } |
200 | } |
202 | |
201 | |
203 | =back |
202 | =back |
204 | |
203 | |
205 | # dynamic methods |
204 | # dynamic methods |
… | |
… | |
211 | =over 4 |
210 | =over 4 |
212 | |
211 | |
213 | =item new Coro \&sub [, @args...] |
212 | =item new Coro \&sub [, @args...] |
214 | |
213 | |
215 | Create a new process and return it. When the sub returns the process |
214 | Create a new process and return it. When the sub returns the process |
216 | automatically terminates. To start the process you must first put it into |
215 | automatically terminates as if C<terminate> with the returned values were |
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216 | called. To make the process run you must first put it into the ready queue |
217 | the ready queue by calling the ready method. |
217 | by calling the ready method. |
218 | |
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219 | The coderef you submit MUST NOT be a closure that refers to variables |
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220 | in an outer scope. This does NOT work. Pass arguments into it instead. |
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221 | |
218 | |
222 | =cut |
219 | =cut |
223 | |
220 | |
224 | sub _newcoro { |
221 | sub _newcoro { |
225 | terminate &{+shift}; |
222 | terminate &{+shift}; |
… | |
… | |
232 | }, $class; |
229 | }, $class; |
233 | } |
230 | } |
234 | |
231 | |
235 | =item $process->ready |
232 | =item $process->ready |
236 | |
233 | |
237 | Put the current process into the ready queue. |
234 | Put the given process into the ready queue. |
238 | |
235 | |
239 | =cut |
236 | =cut |
240 | |
237 | |
241 | sub ready { |
238 | =item $process->cancel (arg...) |
242 | push @ready, $_[0]; |
239 | |
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240 | Temrinates the given process and makes it return the given arguments as |
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241 | status (default: the empty list). |
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242 | |
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243 | =cut |
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244 | |
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245 | sub cancel { |
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246 | my $self = shift; |
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247 | $self->{status} = [@_]; |
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248 | push @destroy, $self; |
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249 | $manager->ready; |
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250 | &schedule if $current == $self; |
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251 | } |
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252 | |
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253 | =item $process->join |
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254 | |
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255 | Wait until the coroutine terminates and return any values given to the |
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256 | C<terminate> or C<cancel> functions. C<join> can be called multiple times |
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257 | from multiple processes. |
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258 | |
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259 | =cut |
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260 | |
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261 | sub join { |
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262 | my $self = shift; |
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263 | unless ($self->{status}) { |
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264 | push @{$self->{join}}, $current; |
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265 | &schedule; |
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266 | } |
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267 | wantarray ? @{$self->{status}} : $self->{status}[0]; |
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268 | } |
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269 | |
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270 | =item $oldprio = $process->prio($newprio) |
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271 | |
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272 | Sets (or gets, if the argument is missing) the priority of the |
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273 | process. Higher priority processes get run before lower priority |
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274 | processes. Priorities are small signed integers (currently -4 .. +3), |
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275 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
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276 | to get then): |
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277 | |
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278 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
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279 | 3 > 1 > 0 > -1 > -3 > -4 |
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280 | |
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281 | # set priority to HIGH |
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282 | current->prio(PRIO_HIGH); |
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283 | |
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284 | The idle coroutine ($Coro::idle) always has a lower priority than any |
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285 | existing coroutine. |
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286 | |
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287 | Changing the priority of the current process will take effect immediately, |
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288 | but changing the priority of processes in the ready queue (but not |
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289 | running) will only take effect after the next schedule (of that |
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290 | process). This is a bug that will be fixed in some future version. |
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291 | |
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292 | =cut |
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293 | |
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294 | sub prio { |
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295 | my $old = $_[0]{prio}; |
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296 | $_[0]{prio} = $_[1] if @_ > 1; |
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297 | $old; |
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298 | } |
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299 | |
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300 | =item $newprio = $process->nice($change) |
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301 | |
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302 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
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303 | higher values mean lower priority, just as in unix). |
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304 | |
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305 | =cut |
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306 | |
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307 | sub nice { |
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308 | $_[0]{prio} -= $_[1]; |
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309 | } |
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310 | |
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311 | =item $olddesc = $process->desc($newdesc) |
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312 | |
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313 | Sets (or gets in case the argument is missing) the description for this |
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314 | process. This is just a free-form string you can associate with a process. |
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315 | |
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316 | =cut |
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317 | |
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318 | sub desc { |
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319 | my $old = $_[0]{desc}; |
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320 | $_[0]{desc} = $_[1] if @_ > 1; |
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321 | $old; |
243 | } |
322 | } |
244 | |
323 | |
245 | =back |
324 | =back |
246 | |
325 | |
247 | =cut |
326 | =cut |
248 | |
327 | |
249 | 1; |
328 | 1; |
250 | |
329 | |
251 | =head1 BUGS/LIMITATIONS |
330 | =head1 BUGS/LIMITATIONS |
252 | |
331 | |
253 | - could be faster, especially when the core would introduce special |
332 | - you must make very sure that no coro is still active on global |
254 | support for coroutines (like it does for threads). |
333 | destruction. very bad things might happen otherwise (usually segfaults). |
255 | - there is still a memleak on coroutine termination that I could not |
334 | |
256 | identify. Could be as small as a single SV. |
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257 | - this module is not well-tested. |
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258 | - if variables or arguments "disappear" (become undef) or become |
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259 | corrupted please contact the author so he cen iron out the |
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260 | remaining bugs. |
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261 | - this module is not thread-safe. You must only ever use this module from |
335 | - this module is not thread-safe. You should only ever use this module |
262 | the same thread (this requirement might be loosened in the future to |
336 | from the same thread (this requirement might be losened in the future |
263 | allow per-thread schedulers, but Coro::State does not yet allow this). |
337 | to allow per-thread schedulers, but Coro::State does not yet allow |
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338 | this). |
264 | |
339 | |
265 | =head1 SEE ALSO |
340 | =head1 SEE ALSO |
266 | |
341 | |
267 | L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
342 | Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
268 | L<Coro::Signal>, L<Coro::State>, L<Coro::Event>. |
343 | |
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344 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
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345 | |
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346 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
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347 | |
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348 | Embedding: L<Coro:MakeMaker> |
269 | |
349 | |
270 | =head1 AUTHOR |
350 | =head1 AUTHOR |
271 | |
351 | |
272 | Marc Lehmann <pcg@goof.com> |
352 | Marc Lehmann <schmorp@schmorp.de> |
273 | http://www.goof.com/pcg/marc/ |
353 | http://home.schmorp.de/ |
274 | |
354 | |
275 | =cut |
355 | =cut |
276 | |
356 | |