| 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 | This module is still experimental, see the BUGS section below. |
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27 | |
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28 | In this module, coroutines are defined as "callchain + lexical variables |
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29 | + @_ + $_ + $@ + $^W + C stack), that is, a coroutine has it's own |
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30 | callchain, it's own set of lexicals and it's own set of perl's most |
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31 | important global variables. |
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32 | |
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33 | =cut |
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34 | |
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35 | package Coro; |
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36 | |
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37 | use Coro::State; |
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38 | |
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39 | use base Exporter; |
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40 | |
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41 | $VERSION = 0.5; |
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42 | |
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43 | @EXPORT = qw(async cede schedule terminate current); |
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44 | %EXPORT_TAGS = ( |
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45 | prio => [qw(PRIO_MAX PRIO_HIGH PRIO_NORMAL PRIO_LOW PRIO_IDLE PRIO_MIN)], |
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46 | ); |
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47 | @EXPORT_OK = @{$EXPORT_TAGS{prio}}; |
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48 | |
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49 | { |
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50 | my @async; |
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51 | my $init; |
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52 | |
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53 | # this way of handling attributes simply is NOT scalable ;() |
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54 | sub import { |
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55 | Coro->export_to_level(1, @_); |
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56 | my $old = *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"}{CODE}; |
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57 | *{(caller)[0]."::MODIFY_CODE_ATTRIBUTES"} = sub { |
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58 | my ($package, $ref) = (shift, shift); |
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59 | my @attrs; |
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60 | for (@_) { |
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61 | if ($_ eq "Coro") { |
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62 | push @async, $ref; |
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63 | unless ($init++) { |
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64 | eval q{ |
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65 | sub INIT { |
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66 | &async(pop @async) while @async; |
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67 | } |
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68 | }; |
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69 | } |
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70 | } else { |
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71 | push @attrs, $_; |
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72 | } |
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73 | } |
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74 | return $old ? $old->($package, $ref, @attrs) : @attrs; |
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75 | }; |
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76 | } |
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77 | |
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78 | } |
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79 | |
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80 | =item $main |
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81 | |
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82 | This coroutine represents the main program. |
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83 | |
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84 | =cut |
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85 | |
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86 | our $main = new Coro; |
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87 | |
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88 | =item $current (or as function: current) |
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89 | |
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90 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
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91 | |
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92 | =cut |
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93 | |
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94 | # maybe some other module used Coro::Specific before... |
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95 | if ($current) { |
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96 | $main->{specific} = $current->{specific}; |
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97 | } |
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98 | |
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99 | our $current = $main; |
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100 | |
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101 | sub current() { $current } |
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102 | |
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103 | =item $idle |
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104 | |
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105 | The coroutine to switch to when no other coroutine is running. The default |
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106 | implementation prints "FATAL: deadlock detected" and exits. |
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107 | |
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108 | =cut |
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109 | |
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110 | # should be done using priorities :( |
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111 | our $idle = new Coro sub { |
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112 | print STDERR "FATAL: deadlock detected\n"; |
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113 | exit(51); |
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114 | }; |
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115 | |
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116 | # this coroutine is necessary because a coroutine |
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117 | # cannot destroy itself. |
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118 | my @destroy; |
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119 | my $manager = new Coro sub { |
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120 | while() { |
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121 | delete ((pop @destroy)->{_coro_state}) while @destroy; |
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122 | &schedule; |
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123 | } |
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124 | }; |
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125 | |
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126 | # static methods. not really. |
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127 | |
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128 | =head2 STATIC METHODS |
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129 | |
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130 | Static methods are actually functions that operate on the current process only. |
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131 | |
| 11 | =over 4 |
132 | =over 4 |
| 12 | |
133 | |
| 13 | =cut |
134 | =item async { ... } [@args...] |
| 14 | |
135 | |
| 15 | package Coro; |
136 | Create a new asynchronous process and return it's process object |
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137 | (usually unused). When the sub returns the new process is automatically |
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138 | terminated. |
| 16 | |
139 | |
| 17 | BEGIN { |
140 | # create a new coroutine that just prints its arguments |
| 18 | $VERSION = 0.01; |
141 | async { |
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142 | print "@_\n"; |
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143 | } 1,2,3,4; |
| 19 | |
144 | |
| 20 | require XSLoader; |
145 | The coderef you submit MUST NOT be a closure that refers to variables |
| 21 | XSLoader::load Coro, $VERSION; |
146 | in an outer scope. This does NOT work. Pass arguments into it instead. |
| 22 | } |
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| 23 | |
147 | |
| 24 | =item $main |
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| 25 | |
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| 26 | This coroutine represents the main program. |
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| 27 | |
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| 28 | =item $current |
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| 29 | |
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| 30 | The current coroutine (the last coroutine switched to). The initial value is C<$main> (of course). |
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| 31 | |
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| 32 | =cut |
148 | =cut |
| 33 | |
149 | |
| 34 | $main = $current = _newprocess { |
150 | sub async(&@) { |
| 35 | # never being called |
151 | my $pid = new Coro @_; |
| 36 | }; |
152 | $manager->ready; # this ensures that the stack is cloned from the manager |
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153 | $pid->ready; |
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154 | $pid; |
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155 | } |
| 37 | |
156 | |
| 38 | =item $error, $error_msg, $error_coro |
157 | =item schedule |
| 39 | |
158 | |
| 40 | This coroutine will be called on fatal errors. C<$error_msg> and |
159 | Calls the scheduler. Please note that the current process will not be put |
| 41 | C<$error_coro> return the error message and the error-causing coroutine, |
160 | into the ready queue, so calling this function usually means you will |
| 42 | respectively. |
161 | never be called again. |
| 43 | |
162 | |
| 44 | =cut |
163 | =cut |
| 45 | |
164 | |
| 46 | $error_msg = |
165 | =item cede |
| 47 | $error_coro = undef; |
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| 48 | |
166 | |
| 49 | $error = _newprocess { |
167 | "Cede" to other processes. This function puts the current process into the |
| 50 | print STDERR "FATAL: $error_msg, program aborted\n"; |
168 | ready queue and calls C<schedule>, which has the effect of giving up the |
| 51 | exit 250; |
169 | current "timeslice" to other coroutines of the same or higher priority. |
| 52 | }; |
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| 53 | |
170 | |
| 54 | =item $coro = new $coderef [, @args] |
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| 55 | |
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| 56 | Create a new coroutine and return it. The first C<resume> call to this |
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| 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 | |
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| 61 | =cut |
171 | =cut |
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172 | |
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173 | =item terminate |
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174 | |
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175 | Terminates the current process. |
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176 | |
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177 | Future versions of this function will allow result arguments. |
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178 | |
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179 | =cut |
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180 | |
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181 | sub terminate { |
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182 | $current->cancel; |
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183 | &schedule; |
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184 | die; # NORETURN |
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185 | } |
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186 | |
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187 | =back |
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188 | |
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189 | # dynamic methods |
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190 | |
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191 | =head2 PROCESS METHODS |
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192 | |
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193 | These are the methods you can call on process objects. |
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194 | |
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195 | =over 4 |
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196 | |
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197 | =item new Coro \&sub [, @args...] |
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198 | |
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199 | Create a new process and return it. When the sub returns the process |
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200 | automatically terminates. To start the process you must first put it into |
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201 | the ready queue by calling the ready method. |
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202 | |
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203 | The coderef you submit MUST NOT be a closure that refers to variables |
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204 | in an outer scope. This does NOT work. Pass arguments into it instead. |
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205 | |
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206 | =cut |
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207 | |
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208 | sub _newcoro { |
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209 | terminate &{+shift}; |
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210 | } |
| 62 | |
211 | |
| 63 | sub new { |
212 | sub new { |
| 64 | my $class = $_[0]; |
213 | my $class = shift; |
| 65 | my $proc = $_[1]; |
214 | bless { |
| 66 | bless _newprocess { |
215 | _coro_state => (new Coro::State $_[0] && \&_newcoro, @_), |
| 67 | do { |
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| 68 | eval { &$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; |
216 | }, $class; |
| 75 | } |
217 | } |
| 76 | |
218 | |
| 77 | =item $coro->resume |
219 | =item $process->ready |
| 78 | |
220 | |
| 79 | Resume execution at the given coroutine. |
221 | Put the current process into the ready queue. |
| 80 | |
222 | |
| 81 | =cut |
223 | =cut |
| 82 | |
224 | |
| 83 | my $prev; |
225 | =item $process->cancel |
| 84 | |
226 | |
| 85 | sub resume { |
227 | Like C<terminate>, but terminates the specified process instead. |
| 86 | $prev = $current; $current = $_[0]; |
228 | |
| 87 | _transfer($prev, $current); |
229 | =cut |
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230 | |
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231 | sub cancel { |
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232 | push @destroy, $_[0]; |
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233 | $manager->ready; |
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234 | &schedule if $current == $_[0]; |
| 88 | } |
235 | } |
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236 | |
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237 | =item $oldprio = $process->prio($newprio) |
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238 | |
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239 | Sets the priority of the process. Higher priority processes get run before |
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240 | lower priority processes. Priorities are smalled signed integer (currently |
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241 | -4 .. +3), that you can refer to using PRIO_xxx constants (use the import |
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242 | tag :prio to get then): |
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243 | |
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244 | PRIO_MAX > PRIO_HIGH > PRIO_NORMAL > PRIO_LOW > PRIO_IDLE > PRIO_MIN |
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245 | 3 > 1 > 0 > -1 > -3 > -4 |
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246 | |
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247 | # set priority to HIGH |
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248 | current->prio(PRIO_HIGH); |
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249 | |
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250 | The idle coroutine ($Coro::idle) always has a lower priority than any |
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251 | existing coroutine. |
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252 | |
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253 | Changing the priority of the current process will take effect immediately, |
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254 | but changing the priority of processes in the ready queue (but not |
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255 | running) will only take effect after the next schedule (of that |
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256 | process). This is a bug that will be fixed in some future version. |
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257 | |
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258 | =cut |
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259 | |
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260 | sub prio { |
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261 | my $old = $_[0]{prio}; |
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262 | $_[0]{prio} = $_[1] if @_ > 1; |
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263 | $old; |
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264 | } |
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265 | |
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266 | =item $newprio = $process->nice($change) |
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267 | |
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268 | Similar to C<prio>, but subtract the given value from the priority (i.e. |
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269 | higher values mean lower priority, just as in unix). |
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270 | |
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271 | =cut |
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272 | |
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273 | sub nice { |
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274 | $_[0]{prio} -= $_[1]; |
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275 | } |
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276 | |
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277 | =back |
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278 | |
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279 | =cut |
| 89 | |
280 | |
| 90 | 1; |
281 | 1; |
| 91 | |
282 | |
| 92 | =back |
283 | =head1 BUGS/LIMITATIONS |
| 93 | |
284 | |
| 94 | =head1 BUGS |
285 | - you must make very sure that no coro is still active on global destruction. |
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286 | very bad things might happen otherwise (usually segfaults). |
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287 | - this module is not thread-safe. You must only ever use this module from |
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288 | the same thread (this requirement might be loosened in the future to |
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289 | allow per-thread schedulers, but Coro::State does not yet allow this). |
| 95 | |
290 | |
| 96 | This module has not yet been extensively tested. |
291 | =head1 SEE ALSO |
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292 | |
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293 | L<Coro::Channel>, L<Coro::Cont>, L<Coro::Specific>, L<Coro::Semaphore>, |
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294 | L<Coro::Signal>, L<Coro::State>, L<Coro::Event>, L<Coro::RWLock>, |
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295 | L<Coro::Handle>, L<Coro::Socket>. |
| 97 | |
296 | |
| 98 | =head1 AUTHOR |
297 | =head1 AUTHOR |
| 99 | |
298 | |
| 100 | Marc Lehmann <pcg@goof.com> |
299 | Marc Lehmann <pcg@goof.com> |
| 101 | http://www.goof.com/pcg/marc/ |
300 | http://www.goof.com/pcg/marc/ |
