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3 | Coro - coroutine process abstraction |
3 | Coro - coroutine process abstraction |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | use Coro; |
7 | use Coro; |
8 | |
8 | |
9 | async { |
9 | async { |
10 | # some asynchronous thread of execution |
10 | # some asynchronous thread of execution |
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11 | print "2\n"; |
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12 | cede; # yield back to main |
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13 | print "4\n"; |
11 | }; |
14 | }; |
12 | |
15 | print "1\n"; |
13 | # alternatively create an async process like this: |
16 | cede; # yield to coroutine |
14 | |
17 | print "3\n"; |
15 | sub some_func : Coro { |
18 | cede; # and again |
16 | # some more async code |
19 | |
17 | } |
20 | # use locking |
18 | |
21 | my $lock = new Coro::Semaphore; |
19 | cede; |
22 | my $locked; |
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23 | |
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24 | $lock->down; |
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25 | $locked = 1; |
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26 | $lock->up; |
20 | |
27 | |
21 | =head1 DESCRIPTION |
28 | =head1 DESCRIPTION |
22 | |
29 | |
23 | This module collection manages coroutines. Coroutines are similar to |
30 | This module collection manages coroutines. Coroutines are similar to |
24 | threads but don't run in parallel. |
31 | threads but don't (in general) run in parallel at the same time even |
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32 | on SMP machines. The specific flavor of coroutine used in this module |
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33 | also guarantees you that it will not switch between coroutines unless |
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34 | necessary, at easily-identified points in your program, so locking and |
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35 | parallel access are rarely an issue, making coroutine programming much |
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36 | safer and easier than threads programming. |
25 | |
37 | |
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38 | Unlike a normal perl program, however, coroutines allow you to have |
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39 | multiple running interpreters that share data, which is especially useful |
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40 | to code pseudo-parallel processes and for event-based programming, such as |
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41 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
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42 | learn more. |
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43 | |
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44 | Coroutines are also useful because Perl has no support for threads (the so |
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45 | called "threads" that perl offers are nothing more than the (bad) process |
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46 | emulation coming from the Windows platform: On standard operating systems |
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47 | they serve no purpose whatsoever, except by making your programs slow and |
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48 | making them use a lot of memory. Best disable them when building perl, or |
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49 | aks your software vendor/distributor to do it for you). |
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50 | |
26 | In this module, coroutines are defined as "callchain + lexical variables |
51 | In this module, coroutines are defined as "callchain + lexical variables + |
27 | + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own |
52 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
28 | callchain, it's own set of lexicals and it's own set of perl's most |
53 | its own set of lexicals and its own set of perls most important global |
29 | important global variables. |
54 | variables (see L<Coro::State> for more configuration). |
30 | |
55 | |
31 | =cut |
56 | =cut |
32 | |
57 | |
33 | package Coro; |
58 | package Coro; |
34 | |
59 | |
35 | BEGIN { eval { require warnings } && warnings->unimport ("uninitialized") } |
60 | use strict; |
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61 | no warnings "uninitialized"; |
36 | |
62 | |
37 | use Coro::State; |
63 | use Coro::State; |
38 | |
64 | |
39 | use vars qw($idle $main $current); |
65 | use base qw(Coro::State Exporter); |
40 | |
66 | |
41 | use base Exporter; |
67 | our $idle; # idle handler |
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68 | our $main; # main coroutine |
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69 | our $current; # current coroutine |
42 | |
70 | |
43 | $VERSION = 0.95; |
71 | our $VERSION = 4.742; |
44 | |
72 | |
45 | @EXPORT = qw(async cede schedule terminate current); |
73 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
46 | %EXPORT_TAGS = ( |
74 | our %EXPORT_TAGS = ( |
47 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
75 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
48 | ); |
76 | ); |
49 | @EXPORT_OK = @{$EXPORT_TAGS{prio}}; |
77 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
50 | |
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51 | { |
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52 | my @async; |
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53 | my $init; |
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54 | |
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55 | # this way of handling attributes simply is NOT scalable ;() |
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56 | sub import { |
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57 | Coro->export_to_level(1, @_); |
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58 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
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59 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
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60 | my ($package, $ref) = (shift, shift); |
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61 | my @attrs; |
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62 | for (@_) { |
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63 | if ($_ eq "Coro") { |
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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 | } |
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72 | } else { |
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73 | push @attrs, $_; |
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74 | } |
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75 | } |
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76 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
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77 | }; |
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78 | } |
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79 | |
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80 | } |
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81 | |
78 | |
82 | =over 4 |
79 | =over 4 |
83 | |
80 | |
84 | =item $main |
81 | =item $Coro::main |
85 | |
82 | |
86 | This coroutine represents the main program. |
83 | This variable stores the coroutine object that represents the main |
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84 | program. While you cna C<ready> it and do most other things you can do to |
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85 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
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86 | wether you are running in the main program or not. |
87 | |
87 | |
88 | =cut |
88 | =cut |
89 | |
89 | |
90 | $main = new Coro; |
90 | $main = new Coro; |
91 | |
91 | |
92 | =item $current (or as function: current) |
92 | =item $Coro::current |
93 | |
93 | |
94 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
94 | The coroutine object representing the current coroutine (the last |
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95 | coroutine that the Coro scheduler switched to). The initial value is |
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96 | C<$main> (of course). |
95 | |
97 | |
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98 | This variable is B<strictly> I<read-only>. You can take copies of the |
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99 | value stored in it and use it as any other coroutine object, but you must |
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100 | not otherwise modify the variable itself. |
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101 | |
96 | =cut |
102 | =cut |
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103 | |
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104 | $main->{desc} = "[main::]"; |
97 | |
105 | |
98 | # maybe some other module used Coro::Specific before... |
106 | # maybe some other module used Coro::Specific before... |
99 | if ($current) { |
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100 | $main->{specific} = $current->{specific}; |
107 | $main->{_specific} = $current->{_specific} |
101 | } |
108 | if $current; |
102 | |
109 | |
103 | $current = $main; |
110 | _set_current $main; |
104 | |
111 | |
105 | sub current() { $current } |
112 | sub current() { $current } # [DEPRECATED] |
106 | |
113 | |
107 | =item $idle |
114 | =item $Coro::idle |
108 | |
115 | |
109 | The coroutine to switch to when no other coroutine is running. The default |
116 | This variable is mainly useful to integrate Coro into event loops. It is |
110 | implementation prints "FATAL: deadlock detected" and exits. |
117 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
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118 | pretty low-level functionality. |
111 | |
119 | |
112 | =cut |
120 | This variable stores a callback that is called whenever the scheduler |
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121 | finds no ready coroutines to run. The default implementation prints |
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122 | "FATAL: deadlock detected" and exits, because the program has no other way |
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123 | to continue. |
113 | |
124 | |
114 | # should be done using priorities :( |
125 | This hook is overwritten by modules such as C<Coro::Timer> and |
115 | $idle = new Coro sub { |
126 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
116 | print STDERR "FATAL: deadlock detected\n"; |
127 | coroutine so the scheduler can run it. |
117 | exit(51); |
128 | |
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129 | Note that the callback I<must not>, under any circumstances, block |
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130 | the current coroutine. Normally, this is achieved by having an "idle |
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131 | coroutine" that calls the event loop and then blocks again, and then |
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132 | readying that coroutine in the idle handler. |
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133 | |
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134 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
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135 | technique. |
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136 | |
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137 | Please note that if your callback recursively invokes perl (e.g. for event |
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138 | handlers), then it must be prepared to be called recursively itself. |
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139 | |
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140 | =cut |
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141 | |
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142 | $idle = sub { |
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143 | require Carp; |
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144 | Carp::croak ("FATAL: deadlock detected"); |
118 | }; |
145 | }; |
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146 | |
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147 | sub _cancel { |
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148 | my ($self) = @_; |
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149 | |
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150 | # free coroutine data and mark as destructed |
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151 | $self->_destroy |
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152 | or return; |
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153 | |
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154 | # call all destruction callbacks |
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155 | $_->(@{$self->{_status}}) |
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156 | for @{(delete $self->{_on_destroy}) || []}; |
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157 | } |
119 | |
158 | |
120 | # this coroutine is necessary because a coroutine |
159 | # this coroutine is necessary because a coroutine |
121 | # cannot destroy itself. |
160 | # cannot destroy itself. |
122 | my @destroy; |
161 | my @destroy; |
123 | my $manager; |
162 | my $manager; |
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163 | |
124 | $manager = new Coro sub { |
164 | $manager = new Coro sub { |
125 | while () { |
165 | while () { |
126 | # by overwriting the state object with the manager we destroy it |
166 | (shift @destroy)->_cancel |
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) { |
167 | while @destroy; |
132 | my $coro = pop @destroy; |
168 | |
133 | $coro->{status} ||= []; |
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134 | $_->ready for @{delete $coro->{join} || []}; |
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135 | $coro->{_coro_state} = $manager->{_coro_state}; |
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136 | } |
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137 | &schedule; |
169 | &schedule; |
138 | } |
170 | } |
139 | }; |
171 | }; |
140 | |
172 | $manager->desc ("[coro manager]"); |
141 | # static methods. not really. |
173 | $manager->prio (PRIO_MAX); |
142 | |
174 | |
143 | =back |
175 | =back |
144 | |
176 | |
145 | =head2 STATIC METHODS |
177 | =head2 SIMPLE COROUTINE CREATION |
146 | |
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147 | Static methods are actually functions that operate on the current process only. |
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148 | |
178 | |
149 | =over 4 |
179 | =over 4 |
150 | |
180 | |
151 | =item async { ... } [@args...] |
181 | =item async { ... } [@args...] |
152 | |
182 | |
153 | Create a new asynchronous process and return it's process object |
183 | Create a new coroutine and return it's coroutine object (usually |
154 | (usually unused). When the sub returns the new process is automatically |
184 | unused). The coroutine will be put into the ready queue, so |
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185 | it will start running automatically on the next scheduler run. |
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186 | |
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187 | The first argument is a codeblock/closure that should be executed in the |
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188 | coroutine. When it returns argument returns the coroutine is automatically |
155 | terminated. |
189 | terminated. |
156 | |
190 | |
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191 | The remaining arguments are passed as arguments to the closure. |
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192 | |
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193 | See the C<Coro::State::new> constructor for info about the coroutine |
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194 | environment in which coroutines are executed. |
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195 | |
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196 | Calling C<exit> in a coroutine will do the same as calling exit outside |
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197 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
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198 | just as it would in the main program. |
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199 | |
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200 | If you do not want that, you can provide a default C<die> handler, or |
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201 | simply avoid dieing (by use of C<eval>). |
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202 | |
157 | # create a new coroutine that just prints its arguments |
203 | Example: Create a new coroutine that just prints its arguments. |
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204 | |
158 | async { |
205 | async { |
159 | print "@_\n"; |
206 | print "@_\n"; |
160 | } 1,2,3,4; |
207 | } 1,2,3,4; |
161 | |
208 | |
162 | =cut |
209 | =cut |
163 | |
210 | |
164 | sub async(&@) { |
211 | sub async(&@) { |
165 | my $pid = new Coro @_; |
212 | my $coro = new Coro @_; |
166 | $manager->ready; # this ensures that the stack is cloned from the manager |
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167 | $pid->ready; |
213 | $coro->ready; |
168 | $pid; |
214 | $coro |
169 | } |
215 | } |
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216 | |
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217 | =item async_pool { ... } [@args...] |
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218 | |
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219 | Similar to C<async>, but uses a coroutine pool, so you should not call |
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220 | terminate or join on it (although you are allowed to), and you get a |
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221 | coroutine that might have executed other code already (which can be good |
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222 | or bad :). |
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223 | |
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224 | On the plus side, this function is faster than creating (and destroying) |
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225 | a completely new coroutine, so if you need a lot of generic coroutines in |
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226 | quick successsion, use C<async_pool>, not C<async>. |
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227 | |
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228 | The code block is executed in an C<eval> context and a warning will be |
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229 | issued in case of an exception instead of terminating the program, as |
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230 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
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231 | will not work in the expected way, unless you call terminate or cancel, |
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232 | which somehow defeats the purpose of pooling (but is fine in the |
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233 | exceptional case). |
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234 | |
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235 | The priority will be reset to C<0> after each run, tracing will be |
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236 | disabled, the description will be reset and the default output filehandle |
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237 | gets restored, so you can change all these. Otherwise the coroutine will |
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238 | be re-used "as-is": most notably if you change other per-coroutine global |
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239 | stuff such as C<$/> you I<must needs> to revert that change, which is most |
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240 | simply done by using local as in: C< local $/ >. |
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241 | |
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242 | The pool size is limited to C<8> idle coroutines (this can be adjusted by |
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243 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
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244 | required. |
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245 | |
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246 | If you are concerned about pooled coroutines growing a lot because a |
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247 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
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248 | { terminate }> once per second or so to slowly replenish the pool. In |
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249 | addition to that, when the stacks used by a handler grows larger than 16kb |
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250 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
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251 | |
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252 | =cut |
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253 | |
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254 | our $POOL_SIZE = 8; |
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255 | our $POOL_RSS = 16 * 1024; |
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256 | our @async_pool; |
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257 | |
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258 | sub pool_handler { |
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259 | my $cb; |
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260 | |
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261 | while () { |
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262 | eval { |
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263 | while () { |
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264 | _pool_1 $cb; |
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265 | &$cb; |
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266 | _pool_2 $cb; |
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267 | &schedule; |
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268 | } |
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269 | }; |
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270 | |
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271 | last if $@ eq "\3async_pool terminate\2\n"; |
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272 | warn $@ if $@; |
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273 | } |
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274 | } |
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275 | |
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276 | sub async_pool(&@) { |
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277 | # this is also inlined into the unlock_scheduler |
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278 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
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279 | |
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280 | $coro->{_invoke} = [@_]; |
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281 | $coro->ready; |
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282 | |
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283 | $coro |
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284 | } |
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285 | |
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286 | =back |
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287 | |
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288 | =head2 STATIC METHODS |
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289 | |
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290 | Static methods are actually functions that operate on the current coroutine. |
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291 | |
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292 | =over 4 |
170 | |
293 | |
171 | =item schedule |
294 | =item schedule |
172 | |
295 | |
173 | Calls the scheduler. Please note that the current process will not be put |
296 | Calls the scheduler. The scheduler will find the next coroutine that is |
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297 | to be run from the ready queue and switches to it. The next coroutine |
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298 | to be run is simply the one with the highest priority that is longest |
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299 | in its ready queue. If there is no coroutine ready, it will clal the |
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300 | C<$Coro::idle> hook. |
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301 | |
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302 | Please note that the current coroutine will I<not> be put into the ready |
174 | into the ready queue, so calling this function usually means you will |
303 | queue, so calling this function usually means you will never be called |
175 | never be called again. |
304 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
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305 | thus waking you up. |
176 | |
306 | |
177 | =cut |
307 | This makes C<schedule> I<the> generic method to use to block the current |
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308 | coroutine and wait for events: first you remember the current coroutine in |
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309 | a variable, then arrange for some callback of yours to call C<< ->ready |
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310 | >> on that once some event happens, and last you call C<schedule> to put |
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311 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
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312 | so you need to check wether the event indeed happened, e.g. by storing the |
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313 | status in a variable. |
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314 | |
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315 | The canonical way to wait on external events is this: |
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316 | |
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317 | { |
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318 | # remember current coroutine |
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319 | my $current = $Coro::current; |
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320 | |
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321 | # register a hypothetical event handler |
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322 | on_event_invoke sub { |
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323 | # wake up sleeping coroutine |
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324 | $current->ready; |
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325 | undef $current; |
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326 | }; |
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327 | |
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328 | # call schedule until event occurred. |
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329 | # in case we are woken up for other reasons |
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330 | # (current still defined), loop. |
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331 | Coro::schedule while $current; |
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332 | } |
178 | |
333 | |
179 | =item cede |
334 | =item cede |
180 | |
335 | |
181 | "Cede" to other processes. This function puts the current process into the |
336 | "Cede" to other coroutines. This function puts the current coroutine into |
182 | ready queue and calls C<schedule>, which has the effect of giving up the |
337 | the ready queue and calls C<schedule>, which has the effect of giving |
183 | current "timeslice" to other coroutines of the same or higher priority. |
338 | up the current "timeslice" to other coroutines of the same or higher |
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339 | priority. Once your coroutine gets its turn again it will automatically be |
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340 | resumed. |
184 | |
341 | |
185 | =cut |
342 | This function is often called C<yield> in other languages. |
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343 | |
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344 | =item Coro::cede_notself |
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345 | |
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346 | Works like cede, but is not exported by default and will cede to I<any> |
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347 | coroutine, regardless of priority. This is useful sometimes to ensure |
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348 | progress is made. |
186 | |
349 | |
187 | =item terminate [arg...] |
350 | =item terminate [arg...] |
188 | |
351 | |
189 | Terminates the current process. |
352 | Terminates the current coroutine with the given status values (see L<cancel>). |
190 | |
353 | |
191 | Future versions of this function will allow result arguments. |
354 | =item killall |
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355 | |
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356 | Kills/terminates/cancels all coroutines except the currently running |
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357 | one. This is useful after a fork, either in the child or the parent, as |
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358 | usually only one of them should inherit the running coroutines. |
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359 | |
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360 | Note that while this will try to free some of the main programs resources, |
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361 | you cnanot free all of them, so if a coroutine that is not the main |
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362 | program calls this function, there will be some one-time resource leak. |
192 | |
363 | |
193 | =cut |
364 | =cut |
194 | |
365 | |
195 | sub terminate { |
366 | sub terminate { |
196 | $current->{status} = [@_]; |
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197 | $current->cancel; |
367 | $current->cancel (@_); |
198 | &schedule; |
368 | } |
199 | die; # NORETURN |
369 | |
|
|
370 | sub killall { |
|
|
371 | for (Coro::State::list) { |
|
|
372 | $_->cancel |
|
|
373 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
|
|
374 | } |
200 | } |
375 | } |
201 | |
376 | |
202 | =back |
377 | =back |
203 | |
378 | |
204 | # dynamic methods |
|
|
205 | |
|
|
206 | =head2 PROCESS METHODS |
379 | =head2 COROUTINE METHODS |
207 | |
380 | |
208 | These are the methods you can call on process objects. |
381 | These are the methods you can call on coroutine objects (or to create |
|
|
382 | them). |
209 | |
383 | |
210 | =over 4 |
384 | =over 4 |
211 | |
385 | |
212 | =item new Coro \&sub [, @args...] |
386 | =item new Coro \&sub [, @args...] |
213 | |
387 | |
214 | Create a new process and return it. When the sub returns the process |
388 | Create a new coroutine and return it. When the sub returns, the coroutine |
215 | automatically terminates as if C<terminate> with the returned values were |
389 | automatically terminates as if C<terminate> with the returned values were |
216 | called. To make the process run you must first put it into the ready queue |
390 | called. To make the coroutine run you must first put it into the ready |
217 | by calling the ready method. |
391 | queue by calling the ready method. |
218 | |
392 | |
219 | =cut |
393 | See C<async> and C<Coro::State::new> for additional info about the |
|
|
394 | coroutine environment. |
220 | |
395 | |
|
|
396 | =cut |
|
|
397 | |
221 | sub _newcoro { |
398 | sub _run_coro { |
222 | terminate &{+shift}; |
399 | terminate &{+shift}; |
223 | } |
400 | } |
224 | |
401 | |
225 | sub new { |
402 | sub new { |
226 | my $class = shift; |
403 | my $class = shift; |
227 | bless { |
|
|
228 | _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), |
|
|
229 | }, $class; |
|
|
230 | } |
|
|
231 | |
404 | |
232 | =item $process->ready |
405 | $class->SUPER::new (\&_run_coro, @_) |
|
|
406 | } |
233 | |
407 | |
234 | Put the given process into the ready queue. |
408 | =item $success = $coroutine->ready |
235 | |
409 | |
236 | =cut |
410 | Put the given coroutine into the end of its ready queue (there is one |
|
|
411 | queue for each priority) and return true. If the coroutine is already in |
|
|
412 | the ready queue, do nothing and return false. |
237 | |
413 | |
238 | =item $process->cancel |
414 | This ensures that the scheduler will resume this coroutine automatically |
|
|
415 | once all the coroutines of higher priority and all coroutines of the same |
|
|
416 | priority that were put into the ready queue earlier have been resumed. |
239 | |
417 | |
240 | Like C<terminate>, but terminates the specified process instead. |
418 | =item $is_ready = $coroutine->is_ready |
|
|
419 | |
|
|
420 | Return wether the coroutine is currently the ready queue or not, |
|
|
421 | |
|
|
422 | =item $coroutine->cancel (arg...) |
|
|
423 | |
|
|
424 | Terminates the given coroutine and makes it return the given arguments as |
|
|
425 | status (default: the empty list). Never returns if the coroutine is the |
|
|
426 | current coroutine. |
241 | |
427 | |
242 | =cut |
428 | =cut |
243 | |
429 | |
244 | sub cancel { |
430 | sub cancel { |
|
|
431 | my $self = shift; |
|
|
432 | $self->{_status} = [@_]; |
|
|
433 | |
|
|
434 | if ($current == $self) { |
245 | push @destroy, $_[0]; |
435 | push @destroy, $self; |
246 | $manager->ready; |
436 | $manager->ready; |
247 | &schedule if $current == $_[0]; |
437 | &schedule while 1; |
|
|
438 | } else { |
|
|
439 | $self->_cancel; |
|
|
440 | } |
248 | } |
441 | } |
249 | |
442 | |
250 | =item $process->join |
443 | =item $coroutine->join |
251 | |
444 | |
252 | Wait until the coroutine terminates and return any values given to the |
445 | Wait until the coroutine terminates and return any values given to the |
253 | C<terminate> function. C<join> can be called multiple times from multiple |
446 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
254 | processes. |
447 | from multiple coroutines, and all will be resumed and given the status |
|
|
448 | return once the C<$coroutine> terminates. |
255 | |
449 | |
256 | =cut |
450 | =cut |
257 | |
451 | |
258 | sub join { |
452 | sub join { |
259 | my $self = shift; |
453 | my $self = shift; |
|
|
454 | |
260 | unless ($self->{status}) { |
455 | unless ($self->{_status}) { |
261 | push @{$self->{join}}, $current; |
456 | my $current = $current; |
262 | &schedule; |
457 | |
|
|
458 | push @{$self->{_on_destroy}}, sub { |
|
|
459 | $current->ready; |
|
|
460 | undef $current; |
|
|
461 | }; |
|
|
462 | |
|
|
463 | &schedule while $current; |
263 | } |
464 | } |
|
|
465 | |
264 | wantarray ? @{$self->{status}} : $self->{status}[0]; |
466 | wantarray ? @{$self->{_status}} : $self->{_status}[0]; |
265 | } |
467 | } |
266 | |
468 | |
|
|
469 | =item $coroutine->on_destroy (\&cb) |
|
|
470 | |
|
|
471 | Registers a callback that is called when this coroutine gets destroyed, |
|
|
472 | but before it is joined. The callback gets passed the terminate arguments, |
|
|
473 | if any, and I<must not> die, under any circumstances. |
|
|
474 | |
|
|
475 | =cut |
|
|
476 | |
|
|
477 | sub on_destroy { |
|
|
478 | my ($self, $cb) = @_; |
|
|
479 | |
|
|
480 | push @{ $self->{_on_destroy} }, $cb; |
|
|
481 | } |
|
|
482 | |
267 | =item $oldprio = $process->prio($newprio) |
483 | =item $oldprio = $coroutine->prio ($newprio) |
268 | |
484 | |
269 | Sets (or gets, if the argument is missing) the priority of the |
485 | Sets (or gets, if the argument is missing) the priority of the |
270 | process. Higher priority processes get run before lower priority |
486 | coroutine. Higher priority coroutines get run before lower priority |
271 | processes. Priorities are small signed integers (currently -4 .. +3), |
487 | coroutines. Priorities are small signed integers (currently -4 .. +3), |
272 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
488 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
273 | to get then): |
489 | to get then): |
274 | |
490 | |
275 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
491 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
276 | 3 > 1 > 0 > -1 > -3 > -4 |
492 | 3 > 1 > 0 > -1 > -3 > -4 |
… | |
… | |
279 | current->prio(PRIO_HIGH); |
495 | current->prio(PRIO_HIGH); |
280 | |
496 | |
281 | The idle coroutine ($Coro::idle) always has a lower priority than any |
497 | The idle coroutine ($Coro::idle) always has a lower priority than any |
282 | existing coroutine. |
498 | existing coroutine. |
283 | |
499 | |
284 | Changing the priority of the current process will take effect immediately, |
500 | Changing the priority of the current coroutine will take effect immediately, |
285 | but changing the priority of processes in the ready queue (but not |
501 | but changing the priority of coroutines in the ready queue (but not |
286 | running) will only take effect after the next schedule (of that |
502 | running) will only take effect after the next schedule (of that |
287 | process). This is a bug that will be fixed in some future version. |
503 | coroutine). This is a bug that will be fixed in some future version. |
288 | |
504 | |
289 | =cut |
|
|
290 | |
|
|
291 | sub prio { |
|
|
292 | my $old = $_[0]{prio}; |
|
|
293 | $_[0]{prio} = $_[1] if @_ > 1; |
|
|
294 | $old; |
|
|
295 | } |
|
|
296 | |
|
|
297 | =item $newprio = $process->nice($change) |
505 | =item $newprio = $coroutine->nice ($change) |
298 | |
506 | |
299 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
507 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
300 | higher values mean lower priority, just as in unix). |
508 | higher values mean lower priority, just as in unix). |
301 | |
509 | |
302 | =cut |
|
|
303 | |
|
|
304 | sub nice { |
|
|
305 | $_[0]{prio} -= $_[1]; |
|
|
306 | } |
|
|
307 | |
|
|
308 | =item $olddesc = $process->desc($newdesc) |
510 | =item $olddesc = $coroutine->desc ($newdesc) |
309 | |
511 | |
310 | Sets (or gets in case the argument is missing) the description for this |
512 | Sets (or gets in case the argument is missing) the description for this |
311 | process. This is just a free-form string you can associate with a process. |
513 | coroutine. This is just a free-form string you can associate with a coroutine. |
|
|
514 | |
|
|
515 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
|
|
516 | can modify this member directly if you wish. |
|
|
517 | |
|
|
518 | =item $coroutine->throw ([$scalar]) |
|
|
519 | |
|
|
520 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
521 | inside the coroutine at the next convinient point in time (usually after |
|
|
522 | it gains control at the next schedule/transfer/cede). Otherwise clears the |
|
|
523 | exception object. |
|
|
524 | |
|
|
525 | The exception object will be thrown "as is" with the specified scalar in |
|
|
526 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
527 | (unlike with C<die>). |
|
|
528 | |
|
|
529 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
530 | end itself, although there is no guarentee that the exception will lead to |
|
|
531 | termination, and if the exception isn't caught it might well end the whole |
|
|
532 | program. |
312 | |
533 | |
313 | =cut |
534 | =cut |
314 | |
535 | |
315 | sub desc { |
536 | sub desc { |
316 | my $old = $_[0]{desc}; |
537 | my $old = $_[0]{desc}; |
… | |
… | |
318 | $old; |
539 | $old; |
319 | } |
540 | } |
320 | |
541 | |
321 | =back |
542 | =back |
322 | |
543 | |
|
|
544 | =head2 GLOBAL FUNCTIONS |
|
|
545 | |
|
|
546 | =over 4 |
|
|
547 | |
|
|
548 | =item Coro::nready |
|
|
549 | |
|
|
550 | Returns the number of coroutines that are currently in the ready state, |
|
|
551 | i.e. that can be switched to by calling C<schedule> directory or |
|
|
552 | indirectly. The value C<0> means that the only runnable coroutine is the |
|
|
553 | currently running one, so C<cede> would have no effect, and C<schedule> |
|
|
554 | would cause a deadlock unless there is an idle handler that wakes up some |
|
|
555 | coroutines. |
|
|
556 | |
|
|
557 | =item my $guard = Coro::guard { ... } |
|
|
558 | |
|
|
559 | This creates and returns a guard object. Nothing happens until the object |
|
|
560 | gets destroyed, in which case the codeblock given as argument will be |
|
|
561 | executed. This is useful to free locks or other resources in case of a |
|
|
562 | runtime error or when the coroutine gets canceled, as in both cases the |
|
|
563 | guard block will be executed. The guard object supports only one method, |
|
|
564 | C<< ->cancel >>, which will keep the codeblock from being executed. |
|
|
565 | |
|
|
566 | Example: set some flag and clear it again when the coroutine gets canceled |
|
|
567 | or the function returns: |
|
|
568 | |
|
|
569 | sub do_something { |
|
|
570 | my $guard = Coro::guard { $busy = 0 }; |
|
|
571 | $busy = 1; |
|
|
572 | |
|
|
573 | # do something that requires $busy to be true |
|
|
574 | } |
|
|
575 | |
|
|
576 | =cut |
|
|
577 | |
|
|
578 | sub guard(&) { |
|
|
579 | bless \(my $cb = $_[0]), "Coro::guard" |
|
|
580 | } |
|
|
581 | |
|
|
582 | sub Coro::guard::cancel { |
|
|
583 | ${$_[0]} = sub { }; |
|
|
584 | } |
|
|
585 | |
|
|
586 | sub Coro::guard::DESTROY { |
|
|
587 | ${$_[0]}->(); |
|
|
588 | } |
|
|
589 | |
|
|
590 | |
|
|
591 | =item unblock_sub { ... } |
|
|
592 | |
|
|
593 | This utility function takes a BLOCK or code reference and "unblocks" it, |
|
|
594 | returning a new coderef. Unblocking means that calling the new coderef |
|
|
595 | will return immediately without blocking, returning nothing, while the |
|
|
596 | original code ref will be called (with parameters) from within another |
|
|
597 | coroutine. |
|
|
598 | |
|
|
599 | The reason this function exists is that many event libraries (such as the |
|
|
600 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
|
|
601 | of thread-safety). This means you must not block within event callbacks, |
|
|
602 | otherwise you might suffer from crashes or worse. The only event library |
|
|
603 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
|
|
604 | |
|
|
605 | This function allows your callbacks to block by executing them in another |
|
|
606 | coroutine where it is safe to block. One example where blocking is handy |
|
|
607 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
|
|
608 | disk, for example. |
|
|
609 | |
|
|
610 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
|
|
611 | creating event callbacks that want to block. |
|
|
612 | |
|
|
613 | If your handler does not plan to block (e.g. simply sends a message to |
|
|
614 | another coroutine, or puts some other coroutine into the ready queue), |
|
|
615 | there is no reason to use C<unblock_sub>. |
|
|
616 | |
|
|
617 | Note that you also need to use C<unblock_sub> for any other callbacks that |
|
|
618 | are indirectly executed by any C-based event loop. For example, when you |
|
|
619 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
|
|
620 | provides callbacks that are the result of some event callback, then you |
|
|
621 | must not block either, or use C<unblock_sub>. |
|
|
622 | |
|
|
623 | =cut |
|
|
624 | |
|
|
625 | our @unblock_queue; |
|
|
626 | |
|
|
627 | # we create a special coro because we want to cede, |
|
|
628 | # to reduce pressure on the coro pool (because most callbacks |
|
|
629 | # return immediately and can be reused) and because we cannot cede |
|
|
630 | # inside an event callback. |
|
|
631 | our $unblock_scheduler = new Coro sub { |
|
|
632 | while () { |
|
|
633 | while (my $cb = pop @unblock_queue) { |
|
|
634 | # this is an inlined copy of async_pool |
|
|
635 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
636 | |
|
|
637 | $coro->{_invoke} = $cb; |
|
|
638 | $coro->ready; |
|
|
639 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
640 | } |
|
|
641 | schedule; # sleep well |
|
|
642 | } |
|
|
643 | }; |
|
|
644 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
|
|
645 | |
|
|
646 | sub unblock_sub(&) { |
|
|
647 | my $cb = shift; |
|
|
648 | |
|
|
649 | sub { |
|
|
650 | unshift @unblock_queue, [$cb, @_]; |
|
|
651 | $unblock_scheduler->ready; |
|
|
652 | } |
|
|
653 | } |
|
|
654 | |
|
|
655 | =back |
|
|
656 | |
323 | =cut |
657 | =cut |
324 | |
658 | |
325 | 1; |
659 | 1; |
326 | |
660 | |
327 | =head1 BUGS/LIMITATIONS |
661 | =head1 BUGS/LIMITATIONS |
328 | |
662 | |
329 | - you must make very sure that no coro is still active on global |
|
|
330 | destruction. very bad things might happen otherwise (usually segfaults). |
|
|
331 | |
|
|
332 | - this module is not thread-safe. You should only ever use this module |
663 | This module is not perl-pseudo-thread-safe. You should only ever use this |
333 | from the same thread (this requirement might be losened in the future |
664 | module from the same thread (this requirement might be removed in the |
334 | to allow per-thread schedulers, but Coro::State does not yet allow |
665 | future to allow per-thread schedulers, but Coro::State does not yet allow |
335 | this). |
666 | this). I recommend disabling thread support and using processes, as this |
|
|
667 | is much faster and uses less memory. |
336 | |
668 | |
337 | =head1 SEE ALSO |
669 | =head1 SEE ALSO |
338 | |
670 | |
339 | L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
671 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
340 | L<Coro::Signal>, L<Coro::State>, L<Coro::Timer>, L<Coro::Event>, |
672 | |
341 | L<Coro::L<Coro::RWLock>, Handle>, L<Coro::Socket>. |
673 | Debugging: L<Coro::Debug>. |
|
|
674 | |
|
|
675 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
|
|
676 | |
|
|
677 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
|
|
678 | |
|
|
679 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
|
|
680 | |
|
|
681 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
|
|
682 | |
|
|
683 | XS API: L<Coro::MakeMaker>. |
|
|
684 | |
|
|
685 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
342 | |
686 | |
343 | =head1 AUTHOR |
687 | =head1 AUTHOR |
344 | |
688 | |
345 | Marc Lehmann <pcg@goof.com> |
689 | Marc Lehmann <schmorp@schmorp.de> |
346 | http://www.goof.com/pcg/marc/ |
690 | http://home.schmorp.de/ |
347 | |
691 | |
348 | =cut |
692 | =cut |
349 | |
693 | |