| 1 | =head1 NAME |
1 | =head1 NAME |
| 2 | |
2 | |
| 3 | Coro - create an manage coroutines |
3 | Coro - coroutine process abstraction |
| 4 | |
4 | |
| 5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
| 6 | |
6 | |
| 7 | use Coro; |
7 | use Coro; |
| 8 | |
8 | |
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9 | async { |
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10 | # some asynchronous thread of execution |
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11 | }; |
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12 | |
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13 | # alternatively create an async process like this: |
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14 | |
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15 | sub some_func : Coro { |
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16 | # some more async code |
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17 | } |
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18 | |
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19 | cede; |
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20 | |
| 9 | =head1 DESCRIPTION |
21 | =head1 DESCRIPTION |
| 10 | |
22 | |
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23 | This module collection manages coroutines. Coroutines are similar to |
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24 | threads but don't run in parallel. |
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25 | |
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26 | In this module, coroutines are defined as "callchain + lexical variables |
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27 | + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own |
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28 | callchain, it's own set of lexicals and it's own set of perl's most |
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29 | important global variables. |
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30 | |
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31 | =cut |
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32 | |
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33 | package Coro; |
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34 | |
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35 | use strict; |
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36 | no warnings "uninitialized"; |
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37 | |
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38 | use Coro::State; |
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39 | |
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40 | use base qw(Coro::State Exporter); |
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41 | |
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42 | our $idle; # idle handler |
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43 | our $main; # main coroutine |
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44 | our $current; # current coroutine |
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45 | |
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46 | our $VERSION = '2.5'; |
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47 | |
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48 | our @EXPORT = qw(async cede schedule terminate current); |
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49 | our %EXPORT_TAGS = ( |
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50 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
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51 | ); |
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52 | our @EXPORT_OK = @{$EXPORT_TAGS{prio}}; |
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53 | |
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54 | { |
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55 | my @async; |
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56 | my $init; |
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57 | |
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58 | # this way of handling attributes simply is NOT scalable ;() |
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59 | sub import { |
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60 | no strict 'refs'; |
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61 | |
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62 | Coro->export_to_level(1, @_); |
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63 | |
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64 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
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65 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
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66 | my ($package, $ref) = (shift, shift); |
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67 | my @attrs; |
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68 | for (@_) { |
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69 | if ($_ eq "Coro") { |
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70 | push @async, $ref; |
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71 | unless ($init++) { |
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72 | eval q{ |
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73 | sub INIT { |
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74 | &async(pop @async) while @async; |
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75 | } |
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76 | }; |
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77 | } |
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78 | } else { |
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79 | push @attrs, $_; |
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80 | } |
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81 | } |
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82 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
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83 | }; |
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84 | } |
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85 | |
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86 | } |
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87 | |
| 11 | =over 4 |
88 | =over 4 |
| 12 | |
89 | |
| 13 | =cut |
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| 14 | |
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| 15 | package Coro; |
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| 16 | |
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| 17 | BEGIN { |
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| 18 | $VERSION = 0.01; |
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| 19 | |
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| 20 | require XSLoader; |
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| 21 | XSLoader::load Coro, $VERSION; |
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| 22 | } |
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| 23 | |
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| 24 | =item $main |
90 | =item $main |
| 25 | |
91 | |
| 26 | This coroutine represents the main program. |
92 | This coroutine represents the main program. |
| 27 | |
93 | |
| 28 | =item $current |
94 | =cut |
| 29 | |
95 | |
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96 | $main = new Coro; |
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97 | |
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98 | =item $current (or as function: current) |
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99 | |
| 30 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
100 | The current coroutine (the last coroutine switched to). The initial value |
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101 | is C<$main> (of course). |
| 31 | |
102 | |
| 32 | =cut |
103 | This variable is B<strictly> I<read-only>. It is provided for performance |
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104 | reasons. If performance is not essentiel you are encouraged to use the |
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105 | C<Coro::current> function instead. |
| 33 | |
106 | |
| 34 | $main = $current = _newprocess { |
107 | =cut |
| 35 | # never being called |
108 | |
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109 | # maybe some other module used Coro::Specific before... |
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110 | if ($current) { |
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111 | $main->{specific} = $current->{specific}; |
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112 | } |
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113 | |
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114 | $current = $main; |
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115 | |
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116 | sub current() { $current } |
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117 | |
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118 | =item $idle |
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119 | |
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120 | A callback that is called whenever the scheduler finds no ready coroutines |
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121 | to run. The default implementation prints "FATAL: deadlock detected" and |
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122 | exits. |
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123 | |
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124 | This hook is overwritten by modules such as C<Coro::Timer> and |
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125 | C<Coro::Event> to wait on an external event that hopefully wakes up some |
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126 | coroutine. |
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127 | |
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128 | =cut |
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129 | |
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130 | $idle = sub { |
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131 | print STDERR "FATAL: deadlock detected\n"; |
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132 | exit (51); |
| 36 | }; |
133 | }; |
| 37 | |
134 | |
| 38 | =item $error, $error_msg, $error_coro |
135 | # this coroutine is necessary because a coroutine |
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136 | # cannot destroy itself. |
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137 | my @destroy; |
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138 | my $manager; |
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139 | $manager = new Coro sub { |
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140 | while () { |
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141 | # by overwriting the state object with the manager we destroy it |
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142 | # while still being able to schedule this coroutine (in case it has |
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143 | # been readied multiple times. this is harmless since the manager |
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144 | # can be called as many times as neccessary and will always |
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145 | # remove itself from the runqueue |
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146 | while (@destroy) { |
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147 | my $coro = pop @destroy; |
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148 | $coro->{status} ||= []; |
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149 | $_->ready for @{delete $coro->{join} || []}; |
| 39 | |
150 | |
| 40 | This coroutine will be called on fatal errors. C<$error_msg> and |
151 | # the next line destroys the coro state, but keeps the |
| 41 | C<$error_coro> return the error message and the error-causing coroutine, |
152 | # process itself intact (we basically make it a zombie |
| 42 | respectively. |
153 | # process that always runs the manager thread, so it's possible |
| 43 | |
154 | # to transfer() to this process). |
| 44 | =cut |
155 | $coro->_clone_state_from ($manager); |
| 45 | |
156 | } |
| 46 | $error_msg = |
157 | &schedule; |
| 47 | $error_coro = undef; |
158 | } |
| 48 | |
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| 49 | $error = _newprocess { |
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| 50 | print STDERR "FATAL: $error_msg, program aborted\n"; |
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| 51 | exit 250; |
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| 52 | }; |
159 | }; |
| 53 | |
160 | |
| 54 | =item $coro = new $coderef [, @args] |
161 | # static methods. not really. |
| 55 | |
162 | |
| 56 | Create a new coroutine and return it. The first C<resume> call to this |
163 | =back |
| 57 | coroutine will start execution at the given coderef. If it returns it |
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| 58 | should return a coroutine to switch to. If, after returning, the coroutine |
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| 59 | is C<resume>d again it starts execution again at the givne coderef. |
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| 60 | |
164 | |
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165 | =head2 STATIC METHODS |
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166 | |
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167 | Static methods are actually functions that operate on the current process only. |
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168 | |
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169 | =over 4 |
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170 | |
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171 | =item async { ... } [@args...] |
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172 | |
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173 | Create a new asynchronous process and return it's process object |
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174 | (usually unused). When the sub returns the new process is automatically |
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175 | terminated. |
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176 | |
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177 | When the coroutine dies, the program will exit, just as in the main |
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178 | program. |
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179 | |
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180 | # create a new coroutine that just prints its arguments |
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181 | async { |
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182 | print "@_\n"; |
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183 | } 1,2,3,4; |
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184 | |
| 61 | =cut |
185 | =cut |
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186 | |
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187 | sub async(&@) { |
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188 | my $pid = new Coro @_; |
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189 | $manager->ready; # this ensures that the stack is cloned from the manager |
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190 | $pid->ready; |
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191 | $pid; |
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192 | } |
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193 | |
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194 | =item schedule |
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195 | |
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196 | Calls the scheduler. Please note that the current process will not be put |
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197 | into the ready queue, so calling this function usually means you will |
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198 | never be called again. |
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199 | |
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200 | =cut |
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201 | |
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202 | =item cede |
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203 | |
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204 | "Cede" to other processes. This function puts the current process into the |
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205 | ready queue and calls C<schedule>, which has the effect of giving up the |
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206 | current "timeslice" to other coroutines of the same or higher priority. |
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207 | |
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208 | =cut |
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209 | |
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210 | =item terminate [arg...] |
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211 | |
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212 | Terminates the current process with the given status values (see L<cancel>). |
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213 | |
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214 | =cut |
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215 | |
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216 | sub terminate { |
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217 | $current->cancel (@_); |
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218 | } |
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219 | |
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220 | =back |
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221 | |
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222 | # dynamic methods |
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223 | |
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224 | =head2 PROCESS METHODS |
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225 | |
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226 | These are the methods you can call on process objects. |
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227 | |
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228 | =over 4 |
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229 | |
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230 | =item new Coro \&sub [, @args...] |
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231 | |
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232 | Create a new process and return it. When the sub returns the process |
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233 | automatically terminates as if C<terminate> with the returned values were |
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234 | called. To make the process run you must first put it into the ready queue |
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235 | by calling the ready method. |
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236 | |
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237 | =cut |
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238 | |
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239 | sub _new_coro { |
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240 | # $current->_clear_idle_sp; # set the idle sp on the following cede |
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241 | _set_cede_self; # ensures that cede cede's us first |
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242 | cede; |
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243 | terminate &{+shift}; |
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244 | } |
| 62 | |
245 | |
| 63 | sub new { |
246 | sub new { |
| 64 | my $class = $_[0]; |
247 | my $class = shift; |
| 65 | my $proc = $_[1]; |
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| 66 | bless _newprocess { |
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| 67 | do { |
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| 68 | eval { &$proc->resume }; |
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| 69 | if ($@) { |
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| 70 | ($error_msg, $error_coro) = ($@, $current); |
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| 71 | $error->resume; |
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| 72 | } |
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| 73 | } while (); |
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| 74 | }, $class; |
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| 75 | } |
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| 76 | |
248 | |
| 77 | =item $coro->resume |
249 | $class->SUPER::new (\&_new_coro, @_) |
| 78 | |
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| 79 | Resume execution at the given coroutine. |
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| 80 | |
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| 81 | =cut |
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| 82 | |
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| 83 | my $prev; |
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| 84 | |
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| 85 | sub resume { |
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| 86 | $prev = $current; $current = $_[0]; |
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| 87 | _transfer($prev, $current); |
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| 88 | } |
250 | } |
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251 | |
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252 | =item $process->ready |
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253 | |
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254 | Put the given process into the ready queue. |
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255 | |
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256 | =cut |
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257 | |
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258 | =item $process->cancel (arg...) |
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259 | |
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260 | Terminates the given process and makes it return the given arguments as |
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261 | status (default: the empty list). |
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262 | |
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263 | =cut |
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264 | |
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265 | sub cancel { |
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266 | my $self = shift; |
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267 | $self->{status} = [@_]; |
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268 | push @destroy, $self; |
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269 | $manager->ready; |
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270 | &schedule if $current == $self; |
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271 | } |
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272 | |
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273 | =item $process->join |
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274 | |
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275 | Wait until the coroutine terminates and return any values given to the |
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276 | C<terminate> or C<cancel> functions. C<join> can be called multiple times |
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277 | from multiple processes. |
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278 | |
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279 | =cut |
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280 | |
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281 | sub join { |
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282 | my $self = shift; |
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283 | unless ($self->{status}) { |
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284 | push @{$self->{join}}, $current; |
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285 | &schedule; |
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286 | } |
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287 | wantarray ? @{$self->{status}} : $self->{status}[0]; |
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288 | } |
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289 | |
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290 | =item $oldprio = $process->prio ($newprio) |
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291 | |
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292 | Sets (or gets, if the argument is missing) the priority of the |
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293 | process. Higher priority processes get run before lower priority |
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294 | processes. Priorities are small signed integers (currently -4 .. +3), |
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295 | that you can refer to using PRIO_xxx constants (use the import tag :prio |
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296 | to get then): |
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297 | |
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298 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
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299 | 3 > 1 > 0 > -1 > -3 > -4 |
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300 | |
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301 | # set priority to HIGH |
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302 | current->prio(PRIO_HIGH); |
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303 | |
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304 | The idle coroutine ($Coro::idle) always has a lower priority than any |
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305 | existing coroutine. |
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306 | |
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307 | Changing the priority of the current process will take effect immediately, |
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308 | but changing the priority of processes in the ready queue (but not |
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309 | running) will only take effect after the next schedule (of that |
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310 | process). This is a bug that will be fixed in some future version. |
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311 | |
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312 | =item $newprio = $process->nice ($change) |
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313 | |
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314 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
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315 | higher values mean lower priority, just as in unix). |
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316 | |
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317 | =item $olddesc = $process->desc ($newdesc) |
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318 | |
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319 | Sets (or gets in case the argument is missing) the description for this |
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320 | process. This is just a free-form string you can associate with a process. |
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321 | |
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322 | =cut |
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323 | |
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324 | sub desc { |
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325 | my $old = $_[0]{desc}; |
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326 | $_[0]{desc} = $_[1] if @_ > 1; |
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327 | $old; |
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328 | } |
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329 | |
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330 | =back |
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331 | |
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332 | =cut |
| 89 | |
333 | |
| 90 | 1; |
334 | 1; |
| 91 | |
335 | |
| 92 | =back |
336 | =head1 BUGS/LIMITATIONS |
| 93 | |
337 | |
| 94 | =head1 BUGS |
338 | - you must make very sure that no coro is still active on global |
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339 | destruction. very bad things might happen otherwise (usually segfaults). |
| 95 | |
340 | |
| 96 | This module has not yet been extensively tested. |
341 | - this module is not thread-safe. You should only ever use this module |
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342 | from the same thread (this requirement might be losened in the future |
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343 | to allow per-thread schedulers, but Coro::State does not yet allow |
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344 | this). |
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345 | |
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346 | =head1 SEE ALSO |
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347 | |
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348 | Support/Utility: L<Coro::Cont>, L<Coro::Specific>, L<Coro::State>, L<Coro::Util>. |
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349 | |
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350 | Locking/IPC: L<Coro::Signal>, L<Coro::Channel>, L<Coro::Semaphore>, L<Coro::SemaphoreSet>, L<Coro::RWLock>. |
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351 | |
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352 | Event/IO: L<Coro::Timer>, L<Coro::Event>, L<Coro::Handle>, L<Coro::Socket>, L<Coro::Select>. |
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353 | |
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354 | Embedding: L<Coro:MakeMaker> |
| 97 | |
355 | |
| 98 | =head1 AUTHOR |
356 | =head1 AUTHOR |
| 99 | |
357 | |
| 100 | Marc Lehmann <pcg@goof.com> |
358 | Marc Lehmann <schmorp@schmorp.de> |
| 101 | http://www.goof.com/pcg/marc/ |
359 | http://home.schmorp.de/ |
| 102 | |
360 | |
| 103 | =cut |
361 | =cut |
| 104 | |
362 | |
