… | |
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2 | |
2 | |
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 coroutine 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 | use Coro::Semaphore; |
19 | cede; |
22 | my $lock = new Coro::Semaphore; |
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23 | my $locked; |
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24 | |
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25 | $lock->down; |
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26 | $locked = 1; |
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27 | $lock->up; |
20 | |
28 | |
21 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
22 | |
30 | |
23 | This module collection manages coroutines. Coroutines are similar |
31 | This module collection manages coroutines. Coroutines are similar to |
24 | to threads but don't run in parallel at the same time even on SMP |
32 | threads but don't (in general) run in parallel at the same time even |
25 | machines. The specific flavor of coroutine used in this module also |
33 | on SMP machines. The specific flavor of coroutine used in this module |
26 | guarantees you that it will not switch between coroutines unless |
34 | also guarantees you that it will not switch between coroutines unless |
27 | necessary, at easily-identified points in your program, so locking and |
35 | necessary, at easily-identified points in your program, so locking and |
28 | parallel access are rarely an issue, making coroutine programming much |
36 | parallel access are rarely an issue, making coroutine programming much |
29 | safer than threads programming. |
37 | safer and easier than threads programming. |
30 | |
38 | |
31 | (Perl, however, does not natively support real threads but instead does a |
39 | Unlike a normal perl program, however, coroutines allow you to have |
32 | very slow and memory-intensive emulation of processes using threads. This |
40 | multiple running interpreters that share data, which is especially useful |
33 | is a performance win on Windows machines, and a loss everywhere else). |
41 | to code pseudo-parallel processes and for event-based programming, such as |
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42 | multiple HTTP-GET requests running concurrently. See L<Coro::AnyEvent> to |
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43 | learn more. |
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44 | |
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45 | Coroutines are also useful because Perl has no support for threads (the so |
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46 | called "threads" that perl offers are nothing more than the (bad) process |
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47 | emulation coming from the Windows platform: On standard operating systems |
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48 | they serve no purpose whatsoever, except by making your programs slow and |
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49 | making them use a lot of memory. Best disable them when building perl, or |
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50 | aks your software vendor/distributor to do it for you). |
34 | |
51 | |
35 | In this module, coroutines are defined as "callchain + lexical variables + |
52 | In this module, coroutines are defined as "callchain + lexical variables + |
36 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
53 | @_ + $_ + $@ + $/ + C stack), that is, a coroutine has its own callchain, |
37 | its own set of lexicals and its own set of perls most important global |
54 | its own set of lexicals and its own set of perls most important global |
38 | variables. |
55 | variables (see L<Coro::State> for more configuration). |
39 | |
56 | |
40 | =cut |
57 | =cut |
41 | |
58 | |
42 | package Coro; |
59 | package Coro; |
43 | |
60 | |
44 | use strict; |
61 | use strict qw(vars subs); |
45 | no warnings "uninitialized"; |
62 | no warnings "uninitialized"; |
46 | |
63 | |
47 | use Coro::State; |
64 | use Coro::State; |
48 | |
65 | |
49 | use base qw(Coro::State Exporter); |
66 | use base qw(Coro::State Exporter); |
50 | |
67 | |
51 | our $idle; # idle handler |
68 | our $idle; # idle handler |
52 | our $main; # main coroutine |
69 | our $main; # main coroutine |
53 | our $current; # current coroutine |
70 | our $current; # current coroutine |
54 | |
71 | |
55 | our $VERSION = '4.0'; |
72 | our $VERSION = "5.0"; |
56 | |
73 | |
57 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
74 | our @EXPORT = qw(async async_pool cede schedule terminate current unblock_sub); |
58 | our %EXPORT_TAGS = ( |
75 | our %EXPORT_TAGS = ( |
59 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
76 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
60 | ); |
77 | ); |
61 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
78 | our @EXPORT_OK = (@{$EXPORT_TAGS{prio}}, qw(nready)); |
62 | |
79 | |
63 | { |
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64 | my @async; |
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65 | my $init; |
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66 | |
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67 | # this way of handling attributes simply is NOT scalable ;() |
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68 | sub import { |
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69 | no strict 'refs'; |
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70 | |
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71 | Coro->export_to_level (1, @_); |
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72 | |
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73 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
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74 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
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75 | my ($package, $ref) = (shift, shift); |
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76 | my @attrs; |
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77 | for (@_) { |
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78 | if ($_ eq "Coro") { |
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79 | push @async, $ref; |
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80 | unless ($init++) { |
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81 | eval q{ |
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82 | sub INIT { |
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83 | &async(pop @async) while @async; |
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84 | } |
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85 | }; |
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86 | } |
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87 | } else { |
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88 | push @attrs, $_; |
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89 | } |
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90 | } |
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91 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
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92 | }; |
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93 | } |
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94 | |
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95 | } |
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96 | |
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97 | =over 4 |
80 | =over 4 |
98 | |
81 | |
99 | =item $main |
82 | =item $Coro::main |
100 | |
83 | |
101 | This coroutine represents the main program. |
84 | This variable stores the coroutine object that represents the main |
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85 | program. While you cna C<ready> it and do most other things you can do to |
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86 | coroutines, it is mainly useful to compare again C<$Coro::current>, to see |
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87 | whether you are running in the main program or not. |
102 | |
88 | |
103 | =cut |
89 | =cut |
104 | |
90 | |
105 | $main = new Coro; |
91 | # $main is now being initialised by Coro::State |
106 | |
92 | |
107 | =item $current (or as function: current) |
93 | =item $Coro::current |
108 | |
94 | |
109 | The current coroutine (the last coroutine switched to). The initial value |
95 | The coroutine object representing the current coroutine (the last |
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96 | coroutine that the Coro scheduler switched to). The initial value is |
110 | is C<$main> (of course). |
97 | C<$Coro::main> (of course). |
111 | |
98 | |
112 | This variable is B<strictly> I<read-only>. It is provided for performance |
99 | This variable is B<strictly> I<read-only>. You can take copies of the |
113 | reasons. If performance is not essential you are encouraged to use the |
100 | value stored in it and use it as any other coroutine object, but you must |
114 | C<Coro::current> function instead. |
101 | not otherwise modify the variable itself. |
115 | |
102 | |
116 | =cut |
103 | =cut |
117 | |
104 | |
118 | $main->{desc} = "[main::]"; |
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119 | |
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120 | # maybe some other module used Coro::Specific before... |
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121 | $main->{_specific} = $current->{_specific} |
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122 | if $current; |
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123 | |
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124 | _set_current $main; |
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125 | |
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126 | sub current() { $current } |
105 | sub current() { $current } # [DEPRECATED] |
127 | |
106 | |
128 | =item $idle |
107 | =item $Coro::idle |
129 | |
108 | |
130 | A callback that is called whenever the scheduler finds no ready coroutines |
109 | This variable is mainly useful to integrate Coro into event loops. It is |
131 | to run. The default implementation prints "FATAL: deadlock detected" and |
110 | usually better to rely on L<Coro::AnyEvent> or LC<Coro::EV>, as this is |
132 | exits, because the program has no other way to continue. |
111 | pretty low-level functionality. |
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112 | |
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113 | This variable stores a callback that is called whenever the scheduler |
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114 | finds no ready coroutines to run. The default implementation prints |
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115 | "FATAL: deadlock detected" and exits, because the program has no other way |
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116 | to continue. |
133 | |
117 | |
134 | This hook is overwritten by modules such as C<Coro::Timer> and |
118 | This hook is overwritten by modules such as C<Coro::Timer> and |
135 | C<Coro::Event> to wait on an external event that hopefully wake up a |
119 | C<Coro::AnyEvent> to wait on an external event that hopefully wake up a |
136 | coroutine so the scheduler can run it. |
120 | coroutine so the scheduler can run it. |
137 | |
121 | |
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122 | Note that the callback I<must not>, under any circumstances, block |
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123 | the current coroutine. Normally, this is achieved by having an "idle |
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124 | coroutine" that calls the event loop and then blocks again, and then |
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125 | readying that coroutine in the idle handler. |
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126 | |
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127 | See L<Coro::Event> or L<Coro::AnyEvent> for examples of using this |
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128 | technique. |
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129 | |
138 | Please note that if your callback recursively invokes perl (e.g. for event |
130 | Please note that if your callback recursively invokes perl (e.g. for event |
139 | handlers), then it must be prepared to be called recursively. |
131 | handlers), then it must be prepared to be called recursively itself. |
140 | |
132 | |
141 | =cut |
133 | =cut |
142 | |
134 | |
143 | $idle = sub { |
135 | $idle = sub { |
144 | require Carp; |
136 | require Carp; |
145 | Carp::croak ("FATAL: deadlock detected"); |
137 | Carp::croak ("FATAL: deadlock detected"); |
146 | }; |
138 | }; |
147 | |
139 | |
148 | sub _cancel { |
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149 | my ($self) = @_; |
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150 | |
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151 | # free coroutine data and mark as destructed |
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152 | $self->_destroy |
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153 | or return; |
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154 | |
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155 | # call all destruction callbacks |
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156 | $_->(@{$self->{_status}}) |
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157 | for @{(delete $self->{_on_destroy}) || []}; |
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158 | } |
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159 | |
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160 | # this coroutine is necessary because a coroutine |
140 | # this coroutine is necessary because a coroutine |
161 | # cannot destroy itself. |
141 | # cannot destroy itself. |
162 | my @destroy; |
142 | our @destroy; |
163 | my $manager; |
143 | our $manager; |
164 | |
144 | |
165 | $manager = new Coro sub { |
145 | $manager = new Coro sub { |
166 | while () { |
146 | while () { |
167 | (shift @destroy)->_cancel |
147 | Coro::_cancel shift @destroy |
168 | while @destroy; |
148 | while @destroy; |
169 | |
149 | |
170 | &schedule; |
150 | &schedule; |
171 | } |
151 | } |
172 | }; |
152 | }; |
173 | $manager->desc ("[coro manager]"); |
153 | $manager->{desc} = "[coro manager]"; |
174 | $manager->prio (PRIO_MAX); |
154 | $manager->prio (PRIO_MAX); |
175 | |
155 | |
176 | # static methods. not really. |
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177 | |
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178 | =back |
156 | =back |
179 | |
157 | |
180 | =head2 STATIC METHODS |
158 | =head2 SIMPLE COROUTINE CREATION |
181 | |
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182 | Static methods are actually functions that operate on the current coroutine only. |
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183 | |
159 | |
184 | =over 4 |
160 | =over 4 |
185 | |
161 | |
186 | =item async { ... } [@args...] |
162 | =item async { ... } [@args...] |
187 | |
163 | |
188 | Create a new asynchronous coroutine and return it's coroutine object |
164 | Create a new coroutine and return it's coroutine object (usually |
189 | (usually unused). When the sub returns the new coroutine is automatically |
165 | unused). The coroutine will be put into the ready queue, so |
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166 | it will start running automatically on the next scheduler run. |
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167 | |
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168 | The first argument is a codeblock/closure that should be executed in the |
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169 | coroutine. When it returns argument returns the coroutine is automatically |
190 | terminated. |
170 | terminated. |
191 | |
171 | |
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172 | The remaining arguments are passed as arguments to the closure. |
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173 | |
192 | See the C<Coro::State::new> constructor for info about the coroutine |
174 | See the C<Coro::State::new> constructor for info about the coroutine |
193 | environment. |
175 | environment in which coroutines are executed. |
194 | |
176 | |
195 | Calling C<exit> in a coroutine will do the same as calling exit outside |
177 | Calling C<exit> in a coroutine will do the same as calling exit outside |
196 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
178 | the coroutine. Likewise, when the coroutine dies, the program will exit, |
197 | just as it would in the main program. |
179 | just as it would in the main program. |
198 | |
180 | |
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181 | If you do not want that, you can provide a default C<die> handler, or |
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182 | simply avoid dieing (by use of C<eval>). |
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183 | |
199 | # create a new coroutine that just prints its arguments |
184 | Example: Create a new coroutine that just prints its arguments. |
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185 | |
200 | async { |
186 | async { |
201 | print "@_\n"; |
187 | print "@_\n"; |
202 | } 1,2,3,4; |
188 | } 1,2,3,4; |
203 | |
189 | |
204 | =cut |
190 | =cut |
… | |
… | |
210 | } |
196 | } |
211 | |
197 | |
212 | =item async_pool { ... } [@args...] |
198 | =item async_pool { ... } [@args...] |
213 | |
199 | |
214 | Similar to C<async>, but uses a coroutine pool, so you should not call |
200 | Similar to C<async>, but uses a coroutine pool, so you should not call |
215 | terminate or join (although you are allowed to), and you get a coroutine |
201 | terminate or join on it (although you are allowed to), and you get a |
216 | that might have executed other code already (which can be good or bad :). |
202 | coroutine that might have executed other code already (which can be good |
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203 | or bad :). |
217 | |
204 | |
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205 | On the plus side, this function is about twice as fast as creating (and |
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206 | destroying) a completely new coroutine, so if you need a lot of generic |
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207 | coroutines in quick successsion, use C<async_pool>, not C<async>. |
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208 | |
218 | Also, the block is executed in an C<eval> context and a warning will be |
209 | The code block is executed in an C<eval> context and a warning will be |
219 | issued in case of an exception instead of terminating the program, as |
210 | issued in case of an exception instead of terminating the program, as |
220 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
211 | C<async> does. As the coroutine is being reused, stuff like C<on_destroy> |
221 | will not work in the expected way, unless you call terminate or cancel, |
212 | will not work in the expected way, unless you call terminate or cancel, |
222 | which somehow defeats the purpose of pooling. |
213 | which somehow defeats the purpose of pooling (but is fine in the |
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214 | exceptional case). |
223 | |
215 | |
224 | The priority will be reset to C<0> after each job, tracing will be |
216 | The priority will be reset to C<0> after each run, tracing will be |
225 | disabled, the description will be reset and the default output filehandle |
217 | disabled, the description will be reset and the default output filehandle |
226 | gets restored, so you can change alkl these. Otherwise the coroutine will |
218 | gets restored, so you can change all these. Otherwise the coroutine will |
227 | be re-used "as-is": most notably if you change other per-coroutine global |
219 | be re-used "as-is": most notably if you change other per-coroutine global |
228 | stuff such as C<$/> you need to revert that change, which is most simply |
220 | stuff such as C<$/> you I<must needs> revert that change, which is most |
229 | done by using local as in C< local $/ >. |
221 | simply done by using local as in: C<< local $/ >>. |
230 | |
222 | |
231 | The pool size is limited to 8 idle coroutines (this can be adjusted by |
223 | The idle pool size is limited to C<8> idle coroutines (this can be |
232 | changing $Coro::POOL_SIZE), and there can be as many non-idle coros as |
224 | adjusted by changing $Coro::POOL_SIZE), but there can be as many non-idle |
233 | required. |
225 | coros as required. |
234 | |
226 | |
235 | If you are concerned about pooled coroutines growing a lot because a |
227 | If you are concerned about pooled coroutines growing a lot because a |
236 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
228 | single C<async_pool> used a lot of stackspace you can e.g. C<async_pool |
237 | { terminate }> once per second or so to slowly replenish the pool. In |
229 | { terminate }> once per second or so to slowly replenish the pool. In |
238 | addition to that, when the stacks used by a handler grows larger than 16kb |
230 | addition to that, when the stacks used by a handler grows larger than 32kb |
239 | (adjustable with $Coro::POOL_RSS) it will also exit. |
231 | (adjustable via $Coro::POOL_RSS) it will also be destroyed. |
240 | |
232 | |
241 | =cut |
233 | =cut |
242 | |
234 | |
243 | our $POOL_SIZE = 8; |
235 | our $POOL_SIZE = 8; |
244 | our $POOL_RSS = 16 * 1024; |
236 | our $POOL_RSS = 32 * 1024; |
245 | our @async_pool; |
237 | our @async_pool; |
246 | |
238 | |
247 | sub pool_handler { |
239 | sub pool_handler { |
248 | my $cb; |
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249 | |
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250 | while () { |
240 | while () { |
251 | eval { |
241 | eval { |
252 | while () { |
242 | &{&_pool_handler} while 1; |
253 | _pool_1 $cb; |
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254 | &$cb; |
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255 | _pool_2 $cb; |
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256 | &schedule; |
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257 | } |
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258 | }; |
243 | }; |
259 | |
244 | |
260 | last if $@ eq "\3terminate\2\n"; |
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261 | warn $@ if $@; |
245 | warn $@ if $@; |
262 | } |
246 | } |
263 | } |
247 | } |
264 | |
248 | |
265 | sub async_pool(&@) { |
249 | =back |
266 | # this is also inlined into the unlock_scheduler |
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267 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
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268 | |
250 | |
269 | $coro->{_invoke} = [@_]; |
251 | =head2 STATIC METHODS |
270 | $coro->ready; |
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271 | |
252 | |
272 | $coro |
253 | Static methods are actually functions that operate on the current coroutine. |
273 | } |
254 | |
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255 | =over 4 |
274 | |
256 | |
275 | =item schedule |
257 | =item schedule |
276 | |
258 | |
277 | Calls the scheduler. Please note that the current coroutine will not be put |
259 | Calls the scheduler. The scheduler will find the next coroutine that is |
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260 | to be run from the ready queue and switches to it. The next coroutine |
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261 | to be run is simply the one with the highest priority that is longest |
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262 | in its ready queue. If there is no coroutine ready, it will clal the |
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263 | C<$Coro::idle> hook. |
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264 | |
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265 | Please note that the current coroutine will I<not> be put into the ready |
278 | into the ready queue, so calling this function usually means you will |
266 | queue, so calling this function usually means you will never be called |
279 | never be called again unless something else (e.g. an event handler) calls |
267 | again unless something else (e.g. an event handler) calls C<< ->ready >>, |
280 | ready. |
268 | thus waking you up. |
281 | |
269 | |
282 | The canonical way to wait on external events is this: |
270 | This makes C<schedule> I<the> generic method to use to block the current |
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271 | coroutine and wait for events: first you remember the current coroutine in |
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272 | a variable, then arrange for some callback of yours to call C<< ->ready |
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273 | >> on that once some event happens, and last you call C<schedule> to put |
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274 | yourself to sleep. Note that a lot of things can wake your coroutine up, |
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275 | so you need to check whether the event indeed happened, e.g. by storing the |
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276 | status in a variable. |
283 | |
277 | |
284 | { |
278 | See B<HOW TO WAIT FOR A CALLBACK>, below, for some ways to wait for callbacks. |
285 | # remember current coroutine |
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286 | my $current = $Coro::current; |
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287 | |
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288 | # register a hypothetical event handler |
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289 | on_event_invoke sub { |
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290 | # wake up sleeping coroutine |
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291 | $current->ready; |
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292 | undef $current; |
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293 | }; |
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294 | |
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295 | # call schedule until event occurred. |
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296 | # in case we are woken up for other reasons |
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297 | # (current still defined), loop. |
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298 | Coro::schedule while $current; |
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299 | } |
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300 | |
279 | |
301 | =item cede |
280 | =item cede |
302 | |
281 | |
303 | "Cede" to other coroutines. This function puts the current coroutine into the |
282 | "Cede" to other coroutines. This function puts the current coroutine into |
304 | ready queue and calls C<schedule>, which has the effect of giving up the |
283 | the ready queue and calls C<schedule>, which has the effect of giving |
305 | current "timeslice" to other coroutines of the same or higher priority. |
284 | up the current "timeslice" to other coroutines of the same or higher |
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285 | priority. Once your coroutine gets its turn again it will automatically be |
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286 | resumed. |
306 | |
287 | |
307 | Returns true if at least one coroutine switch has happened. |
288 | This function is often called C<yield> in other languages. |
308 | |
289 | |
309 | =item Coro::cede_notself |
290 | =item Coro::cede_notself |
310 | |
291 | |
311 | Works like cede, but is not exported by default and will cede to any |
292 | Works like cede, but is not exported by default and will cede to I<any> |
312 | coroutine, regardless of priority, once. |
293 | coroutine, regardless of priority. This is useful sometimes to ensure |
313 | |
294 | progress is made. |
314 | Returns true if at least one coroutine switch has happened. |
|
|
315 | |
295 | |
316 | =item terminate [arg...] |
296 | =item terminate [arg...] |
317 | |
297 | |
318 | Terminates the current coroutine with the given status values (see L<cancel>). |
298 | Terminates the current coroutine with the given status values (see L<cancel>). |
319 | |
299 | |
… | |
… | |
321 | |
301 | |
322 | Kills/terminates/cancels all coroutines except the currently running |
302 | Kills/terminates/cancels all coroutines except the currently running |
323 | one. This is useful after a fork, either in the child or the parent, as |
303 | one. This is useful after a fork, either in the child or the parent, as |
324 | usually only one of them should inherit the running coroutines. |
304 | usually only one of them should inherit the running coroutines. |
325 | |
305 | |
326 | =cut |
306 | Note that while this will try to free some of the main programs resources, |
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|
307 | you cannot free all of them, so if a coroutine that is not the main |
|
|
308 | program calls this function, there will be some one-time resource leak. |
327 | |
309 | |
328 | sub terminate { |
310 | =cut |
329 | $current->cancel (@_); |
|
|
330 | } |
|
|
331 | |
311 | |
332 | sub killall { |
312 | sub killall { |
333 | for (Coro::State::list) { |
313 | for (Coro::State::list) { |
334 | $_->cancel |
314 | $_->cancel |
335 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
315 | if $_ != $current && UNIVERSAL::isa $_, "Coro"; |
336 | } |
316 | } |
337 | } |
317 | } |
338 | |
318 | |
339 | =back |
319 | =back |
340 | |
320 | |
341 | # dynamic methods |
|
|
342 | |
|
|
343 | =head2 COROUTINE METHODS |
321 | =head2 COROUTINE METHODS |
344 | |
322 | |
345 | These are the methods you can call on coroutine objects. |
323 | These are the methods you can call on coroutine objects (or to create |
|
|
324 | them). |
346 | |
325 | |
347 | =over 4 |
326 | =over 4 |
348 | |
327 | |
349 | =item new Coro \&sub [, @args...] |
328 | =item new Coro \&sub [, @args...] |
350 | |
329 | |
351 | Create a new coroutine and return it. When the sub returns the coroutine |
330 | Create a new coroutine and return it. When the sub returns, the coroutine |
352 | automatically terminates as if C<terminate> with the returned values were |
331 | automatically terminates as if C<terminate> with the returned values were |
353 | called. To make the coroutine run you must first put it into the ready queue |
332 | called. To make the coroutine run you must first put it into the ready |
354 | by calling the ready method. |
333 | queue by calling the ready method. |
355 | |
334 | |
356 | See C<async> and C<Coro::State::new> for additional info about the |
335 | See C<async> and C<Coro::State::new> for additional info about the |
357 | coroutine environment. |
336 | coroutine environment. |
358 | |
337 | |
359 | =cut |
338 | =cut |
360 | |
339 | |
361 | sub _run_coro { |
340 | sub _terminate { |
362 | terminate &{+shift}; |
341 | terminate &{+shift}; |
363 | } |
342 | } |
364 | |
343 | |
365 | sub new { |
|
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366 | my $class = shift; |
|
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367 | |
|
|
368 | $class->SUPER::new (\&_run_coro, @_) |
|
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369 | } |
|
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370 | |
|
|
371 | =item $success = $coroutine->ready |
344 | =item $success = $coroutine->ready |
372 | |
345 | |
373 | Put the given coroutine into the ready queue (according to it's priority) |
346 | Put the given coroutine into the end of its ready queue (there is one |
374 | and return true. If the coroutine is already in the ready queue, do nothing |
347 | queue for each priority) and return true. If the coroutine is already in |
375 | and return false. |
348 | the ready queue, do nothing and return false. |
|
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349 | |
|
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350 | This ensures that the scheduler will resume this coroutine automatically |
|
|
351 | once all the coroutines of higher priority and all coroutines of the same |
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352 | priority that were put into the ready queue earlier have been resumed. |
376 | |
353 | |
377 | =item $is_ready = $coroutine->is_ready |
354 | =item $is_ready = $coroutine->is_ready |
378 | |
355 | |
379 | Return wether the coroutine is currently the ready queue or not, |
356 | Return whether the coroutine is currently the ready queue or not, |
380 | |
357 | |
381 | =item $coroutine->cancel (arg...) |
358 | =item $coroutine->cancel (arg...) |
382 | |
359 | |
383 | Terminates the given coroutine and makes it return the given arguments as |
360 | Terminates the given coroutine and makes it return the given arguments as |
384 | status (default: the empty list). Never returns if the coroutine is the |
361 | status (default: the empty list). Never returns if the coroutine is the |
… | |
… | |
386 | |
363 | |
387 | =cut |
364 | =cut |
388 | |
365 | |
389 | sub cancel { |
366 | sub cancel { |
390 | my $self = shift; |
367 | my $self = shift; |
391 | $self->{_status} = [@_]; |
|
|
392 | |
368 | |
393 | if ($current == $self) { |
369 | if ($current == $self) { |
394 | push @destroy, $self; |
370 | terminate @_; |
395 | $manager->ready; |
|
|
396 | &schedule while 1; |
|
|
397 | } else { |
371 | } else { |
|
|
372 | $self->{_status} = [@_]; |
398 | $self->_cancel; |
373 | $self->_cancel; |
399 | } |
374 | } |
400 | } |
375 | } |
|
|
376 | |
|
|
377 | =item $coroutine->schedule_to |
|
|
378 | |
|
|
379 | Puts the current coroutine to sleep (like C<Coro::schedule>), but instead |
|
|
380 | of continuing with the next coro from the ready queue, always switch to |
|
|
381 | the given coroutine object (regardless of priority etc.). The readyness |
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382 | state of that coroutine isn't changed. |
|
|
383 | |
|
|
384 | This is an advanced method for special cases - I'd love to hear about any |
|
|
385 | uses for this one. |
|
|
386 | |
|
|
387 | =item $coroutine->cede_to |
|
|
388 | |
|
|
389 | Like C<schedule_to>, but puts the current coroutine into the ready |
|
|
390 | queue. This has the effect of temporarily switching to the given |
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391 | coroutine, and continuing some time later. |
|
|
392 | |
|
|
393 | This is an advanced method for special cases - I'd love to hear about any |
|
|
394 | uses for this one. |
|
|
395 | |
|
|
396 | =item $coroutine->throw ([$scalar]) |
|
|
397 | |
|
|
398 | If C<$throw> is specified and defined, it will be thrown as an exception |
|
|
399 | inside the coroutine at the next convenient point in time. Otherwise |
|
|
400 | clears the exception object. |
|
|
401 | |
|
|
402 | Coro will check for the exception each time a schedule-like-function |
|
|
403 | returns, i.e. after each C<schedule>, C<cede>, C<< Coro::Semaphore->down |
|
|
404 | >>, C<< Coro::Handle->readable >> and so on. Most of these functions |
|
|
405 | detect this case and return early in case an exception is pending. |
|
|
406 | |
|
|
407 | The exception object will be thrown "as is" with the specified scalar in |
|
|
408 | C<$@>, i.e. if it is a string, no line number or newline will be appended |
|
|
409 | (unlike with C<die>). |
|
|
410 | |
|
|
411 | This can be used as a softer means than C<cancel> to ask a coroutine to |
|
|
412 | end itself, although there is no guarantee that the exception will lead to |
|
|
413 | termination, and if the exception isn't caught it might well end the whole |
|
|
414 | program. |
|
|
415 | |
|
|
416 | You might also think of C<throw> as being the moral equivalent of |
|
|
417 | C<kill>ing a coroutine with a signal (in this case, a scalar). |
401 | |
418 | |
402 | =item $coroutine->join |
419 | =item $coroutine->join |
403 | |
420 | |
404 | Wait until the coroutine terminates and return any values given to the |
421 | Wait until the coroutine terminates and return any values given to the |
405 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
422 | C<terminate> or C<cancel> functions. C<join> can be called concurrently |
406 | from multiple coroutines. |
423 | from multiple coroutines, and all will be resumed and given the status |
|
|
424 | return once the C<$coroutine> terminates. |
407 | |
425 | |
408 | =cut |
426 | =cut |
409 | |
427 | |
410 | sub join { |
428 | sub join { |
411 | my $self = shift; |
429 | my $self = shift; |
… | |
… | |
426 | |
444 | |
427 | =item $coroutine->on_destroy (\&cb) |
445 | =item $coroutine->on_destroy (\&cb) |
428 | |
446 | |
429 | Registers a callback that is called when this coroutine gets destroyed, |
447 | Registers a callback that is called when this coroutine gets destroyed, |
430 | but before it is joined. The callback gets passed the terminate arguments, |
448 | but before it is joined. The callback gets passed the terminate arguments, |
431 | if any. |
449 | if any, and I<must not> die, under any circumstances. |
432 | |
450 | |
433 | =cut |
451 | =cut |
434 | |
452 | |
435 | sub on_destroy { |
453 | sub on_destroy { |
436 | my ($self, $cb) = @_; |
454 | my ($self, $cb) = @_; |
… | |
… | |
466 | higher values mean lower priority, just as in unix). |
484 | higher values mean lower priority, just as in unix). |
467 | |
485 | |
468 | =item $olddesc = $coroutine->desc ($newdesc) |
486 | =item $olddesc = $coroutine->desc ($newdesc) |
469 | |
487 | |
470 | Sets (or gets in case the argument is missing) the description for this |
488 | Sets (or gets in case the argument is missing) the description for this |
471 | coroutine. This is just a free-form string you can associate with a coroutine. |
489 | coroutine. This is just a free-form string you can associate with a |
|
|
490 | coroutine. |
472 | |
491 | |
473 | This method simply sets the C<< $coroutine->{desc} >> member to the given string. You |
492 | This method simply sets the C<< $coroutine->{desc} >> member to the given |
474 | can modify this member directly if you wish. |
493 | string. You can modify this member directly if you wish. |
475 | |
494 | |
476 | =cut |
495 | =cut |
477 | |
496 | |
478 | sub desc { |
497 | sub desc { |
479 | my $old = $_[0]{desc}; |
498 | my $old = $_[0]{desc}; |
480 | $_[0]{desc} = $_[1] if @_ > 1; |
499 | $_[0]{desc} = $_[1] if @_ > 1; |
481 | $old; |
500 | $old; |
482 | } |
501 | } |
483 | |
502 | |
|
|
503 | sub transfer { |
|
|
504 | require Carp; |
|
|
505 | Carp::croak ("You must not call ->transfer on Coro objects. Use Coro::State objects or the ->schedule_to method. Caught"); |
|
|
506 | } |
|
|
507 | |
484 | =back |
508 | =back |
485 | |
509 | |
486 | =head2 GLOBAL FUNCTIONS |
510 | =head2 GLOBAL FUNCTIONS |
487 | |
511 | |
488 | =over 4 |
512 | =over 4 |
489 | |
513 | |
490 | =item Coro::nready |
514 | =item Coro::nready |
491 | |
515 | |
492 | Returns the number of coroutines that are currently in the ready state, |
516 | Returns the number of coroutines that are currently in the ready state, |
493 | i.e. that can be switched to. The value C<0> means that the only runnable |
517 | i.e. that can be switched to by calling C<schedule> directory or |
|
|
518 | indirectly. The value C<0> means that the only runnable coroutine is the |
494 | coroutine is the currently running one, so C<cede> would have no effect, |
519 | currently running one, so C<cede> would have no effect, and C<schedule> |
495 | and C<schedule> would cause a deadlock unless there is an idle handler |
520 | would cause a deadlock unless there is an idle handler that wakes up some |
496 | that wakes up some coroutines. |
521 | coroutines. |
497 | |
522 | |
498 | =item my $guard = Coro::guard { ... } |
523 | =item my $guard = Coro::guard { ... } |
499 | |
524 | |
500 | This creates and returns a guard object. Nothing happens until the object |
525 | This creates and returns a guard object. Nothing happens until the object |
501 | gets destroyed, in which case the codeblock given as argument will be |
526 | gets destroyed, in which case the codeblock given as argument will be |
… | |
… | |
530 | |
555 | |
531 | |
556 | |
532 | =item unblock_sub { ... } |
557 | =item unblock_sub { ... } |
533 | |
558 | |
534 | This utility function takes a BLOCK or code reference and "unblocks" it, |
559 | This utility function takes a BLOCK or code reference and "unblocks" it, |
535 | returning the new coderef. This means that the new coderef will return |
560 | returning a new coderef. Unblocking means that calling the new coderef |
536 | immediately without blocking, returning nothing, while the original code |
561 | will return immediately without blocking, returning nothing, while the |
537 | ref will be called (with parameters) from within its own coroutine. |
562 | original code ref will be called (with parameters) from within another |
|
|
563 | coroutine. |
538 | |
564 | |
539 | The reason this function exists is that many event libraries (such as the |
565 | The reason this function exists is that many event libraries (such as the |
540 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
566 | venerable L<Event|Event> module) are not coroutine-safe (a weaker form |
541 | of thread-safety). This means you must not block within event callbacks, |
567 | of thread-safety). This means you must not block within event callbacks, |
542 | otherwise you might suffer from crashes or worse. |
568 | otherwise you might suffer from crashes or worse. The only event library |
|
|
569 | currently known that is safe to use without C<unblock_sub> is L<EV>. |
543 | |
570 | |
544 | This function allows your callbacks to block by executing them in another |
571 | This function allows your callbacks to block by executing them in another |
545 | coroutine where it is safe to block. One example where blocking is handy |
572 | coroutine where it is safe to block. One example where blocking is handy |
546 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
573 | is when you use the L<Coro::AIO|Coro::AIO> functions to save results to |
547 | disk. |
574 | disk, for example. |
548 | |
575 | |
549 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
576 | In short: simply use C<unblock_sub { ... }> instead of C<sub { ... }> when |
550 | creating event callbacks that want to block. |
577 | creating event callbacks that want to block. |
|
|
578 | |
|
|
579 | If your handler does not plan to block (e.g. simply sends a message to |
|
|
580 | another coroutine, or puts some other coroutine into the ready queue), |
|
|
581 | there is no reason to use C<unblock_sub>. |
|
|
582 | |
|
|
583 | Note that you also need to use C<unblock_sub> for any other callbacks that |
|
|
584 | are indirectly executed by any C-based event loop. For example, when you |
|
|
585 | use a module that uses L<AnyEvent> (and you use L<Coro::AnyEvent>) and it |
|
|
586 | provides callbacks that are the result of some event callback, then you |
|
|
587 | must not block either, or use C<unblock_sub>. |
551 | |
588 | |
552 | =cut |
589 | =cut |
553 | |
590 | |
554 | our @unblock_queue; |
591 | our @unblock_queue; |
555 | |
592 | |
… | |
… | |
558 | # return immediately and can be reused) and because we cannot cede |
595 | # return immediately and can be reused) and because we cannot cede |
559 | # inside an event callback. |
596 | # inside an event callback. |
560 | our $unblock_scheduler = new Coro sub { |
597 | our $unblock_scheduler = new Coro sub { |
561 | while () { |
598 | while () { |
562 | while (my $cb = pop @unblock_queue) { |
599 | while (my $cb = pop @unblock_queue) { |
563 | # this is an inlined copy of async_pool |
600 | &async_pool (@$cb); |
564 | my $coro = (pop @async_pool) || new Coro \&pool_handler; |
|
|
565 | |
601 | |
566 | $coro->{_invoke} = $cb; |
|
|
567 | $coro->ready; |
|
|
568 | cede; # for short-lived callbacks, this reduces pressure on the coro pool |
602 | # for short-lived callbacks, this reduces pressure on the coro pool |
|
|
603 | # as the chance is very high that the async_poll coro will be back |
|
|
604 | # in the idle state when cede returns |
|
|
605 | cede; |
569 | } |
606 | } |
570 | schedule; # sleep well |
607 | schedule; # sleep well |
571 | } |
608 | } |
572 | }; |
609 | }; |
573 | $unblock_scheduler->desc ("[unblock_sub scheduler]"); |
610 | $unblock_scheduler->{desc} = "[unblock_sub scheduler]"; |
574 | |
611 | |
575 | sub unblock_sub(&) { |
612 | sub unblock_sub(&) { |
576 | my $cb = shift; |
613 | my $cb = shift; |
577 | |
614 | |
578 | sub { |
615 | sub { |
579 | unshift @unblock_queue, [$cb, @_]; |
616 | unshift @unblock_queue, [$cb, @_]; |
580 | $unblock_scheduler->ready; |
617 | $unblock_scheduler->ready; |
581 | } |
618 | } |
582 | } |
619 | } |
583 | |
620 | |
|
|
621 | =item $cb = Coro::rouse_cb |
|
|
622 | |
|
|
623 | Create and return a "rouse callback". That's a code reference that, when |
|
|
624 | called, will save its arguments and notify the owner coroutine of the |
|
|
625 | callback. |
|
|
626 | |
|
|
627 | See the next function. |
|
|
628 | |
|
|
629 | =item @args = Coro::rouse_wait [$cb] |
|
|
630 | |
|
|
631 | Wait for the specified rouse callback (or the last one tht was created in |
|
|
632 | this coroutine). |
|
|
633 | |
|
|
634 | As soon as the callback is invoked (or when the calback was invoked before |
|
|
635 | C<rouse_wait>), it will return a copy of the arguments originally passed |
|
|
636 | to the rouse callback. |
|
|
637 | |
|
|
638 | See the section B<HOW TO WAIT FOR A CALLBACK> for an actual usage example. |
|
|
639 | |
584 | =back |
640 | =back |
585 | |
641 | |
586 | =cut |
642 | =cut |
587 | |
643 | |
588 | 1; |
644 | 1; |
589 | |
645 | |
|
|
646 | =head1 HOW TO WAIT FOR A CALLBACK |
|
|
647 | |
|
|
648 | It is very common for a coroutine to wait for some callback to be |
|
|
649 | called. This occurs naturally when you use coroutines in an otherwise |
|
|
650 | event-based program, or when you use event-based libraries. |
|
|
651 | |
|
|
652 | These typically register a callback for some event, and call that callback |
|
|
653 | when the event occured. In a coroutine, however, you typically want to |
|
|
654 | just wait for the event, simplyifying things. |
|
|
655 | |
|
|
656 | For example C<< AnyEvent->child >> registers a callback to be called when |
|
|
657 | a specific child has exited: |
|
|
658 | |
|
|
659 | my $child_watcher = AnyEvent->child (pid => $pid, cb => sub { ... }); |
|
|
660 | |
|
|
661 | But from withina coroutine, you often just want to write this: |
|
|
662 | |
|
|
663 | my $status = wait_for_child $pid; |
|
|
664 | |
|
|
665 | Coro offers two functions specifically designed to make this easy, |
|
|
666 | C<Coro::rouse_cb> and C<Coro::rouse_wait>. |
|
|
667 | |
|
|
668 | The first function, C<rouse_cb>, generates and returns a callback that, |
|
|
669 | when invoked, will save it's arguments and notify the coroutine that |
|
|
670 | created the callback. |
|
|
671 | |
|
|
672 | The second function, C<rouse_wait>, waits for the callback to be called |
|
|
673 | (by calling C<schedule> to go to sleep) and returns the arguments |
|
|
674 | originally passed to the callback. |
|
|
675 | |
|
|
676 | Using these functions, it becomes easy to write the C<wait_for_child> |
|
|
677 | function mentioned above: |
|
|
678 | |
|
|
679 | sub wait_for_child($) { |
|
|
680 | my ($pid) = @_; |
|
|
681 | |
|
|
682 | my $watcher = AnyEvent->child (pid => $pid, cb => Coro::rouse_cb); |
|
|
683 | |
|
|
684 | my ($rpid, $rstatus) = Coro::rouse_wait; |
|
|
685 | $rstatus |
|
|
686 | } |
|
|
687 | |
|
|
688 | In the case where C<rouse_cb> and C<rouse_wait> are not flexible enough, |
|
|
689 | you can roll your own, using C<schedule>: |
|
|
690 | |
|
|
691 | sub wait_for_child($) { |
|
|
692 | my ($pid) = @_; |
|
|
693 | |
|
|
694 | # store the current coroutine in $current, |
|
|
695 | # and provide result variables for the closure passed to ->child |
|
|
696 | my $current = $Coro::current; |
|
|
697 | my ($done, $rstatus); |
|
|
698 | |
|
|
699 | # pass a closure to ->child |
|
|
700 | my $watcher = AnyEvent->child (pid => $pid, cb => sub { |
|
|
701 | $rstatus = $_[1]; # remember rstatus |
|
|
702 | $done = 1; # mark $rstatus as valud |
|
|
703 | }); |
|
|
704 | |
|
|
705 | # wait until the closure has been called |
|
|
706 | schedule while !$done; |
|
|
707 | |
|
|
708 | $rstatus |
|
|
709 | } |
|
|
710 | |
|
|
711 | |
590 | =head1 BUGS/LIMITATIONS |
712 | =head1 BUGS/LIMITATIONS |
591 | |
713 | |
592 | - you must make very sure that no coro is still active on global |
714 | =over 4 |
593 | destruction. very bad things might happen otherwise (usually segfaults). |
|
|
594 | |
715 | |
|
|
716 | =item fork with pthread backend |
|
|
717 | |
|
|
718 | When Coro is compiled using the pthread backend (which isn't recommended |
|
|
719 | but required on many BSDs as their libcs are completely broken), then |
|
|
720 | coroutines will not survive a fork. There is no known workaround except to |
|
|
721 | fix your libc and use a saner backend. |
|
|
722 | |
|
|
723 | =item perl process emulation ("threads") |
|
|
724 | |
595 | - this module is not thread-safe. You should only ever use this module |
725 | This module is not perl-pseudo-thread-safe. You should only ever use this |
596 | from the same thread (this requirement might be loosened in the future |
726 | module from the same thread (this requirement might be removed in the |
597 | to allow per-thread schedulers, but Coro::State does not yet allow |
727 | future to allow per-thread schedulers, but Coro::State does not yet allow |
598 | this). |
728 | this). I recommend disabling thread support and using processes, as having |
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729 | the windows process emulation enabled under unix roughly halves perl |
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730 | performance, even when not used. |
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731 | |
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732 | =item coroutine switching not signal safe |
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733 | |
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734 | You must not switch to another coroutine from within a signal handler |
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735 | (only relevant with %SIG - most event libraries provide safe signals). |
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736 | |
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737 | That means you I<MUST NOT> call any function that might "block" the |
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738 | current coroutine - C<cede>, C<schedule> C<< Coro::Semaphore->down >> or |
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739 | anything that calls those. Everything else, including calling C<ready>, |
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740 | works. |
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741 | |
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742 | =back |
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743 | |
599 | |
744 | |
600 | =head1 SEE ALSO |
745 | =head1 SEE ALSO |
601 | |
746 | |
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747 | Event-Loop integration: L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>. |
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748 | |
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749 | Debugging: L<Coro::Debug>. |
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750 | |
602 | Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
751 | Support/Utility: L<Coro::Specific>, L<Coro::Util>. |
603 | |
752 | |
604 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
753 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
605 | |
754 | |
606 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
755 | IO/Timers: L<Coro::Timer>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::AIO>. |
607 | |
756 | |
608 | Embedding: L<Coro:MakeMaker> |
757 | Compatibility: L<Coro::LWP>, L<Coro::BDB>, L<Coro::Storable>, L<Coro::Select>. |
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758 | |
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759 | XS API: L<Coro::MakeMaker>. |
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760 | |
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761 | Low level Configuration, Coroutine Environment: L<Coro::State>. |
609 | |
762 | |
610 | =head1 AUTHOR |
763 | =head1 AUTHOR |
611 | |
764 | |
612 | Marc Lehmann <schmorp@schmorp.de> |
765 | Marc Lehmann <schmorp@schmorp.de> |
613 | http://home.schmorp.de/ |
766 | http://home.schmorp.de/ |