1 | =head1 NAME |
1 | =head1 NAME |
2 | |
2 | |
3 | AnyEvent - provide framework for multiple event loops |
3 | AnyEvent - provide framework for multiple event loops |
4 | |
4 | |
5 | Event, Coro, Glib, Tk - various supported event loops |
5 | EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt - various supported event loops |
6 | |
6 | |
7 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
8 | |
8 | |
9 | use AnyEvent; |
9 | use AnyEvent; |
10 | |
10 | |
11 | my $w = AnyEvent->io (fh => ..., poll => "[rw]+", cb => sub { |
11 | my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { |
12 | my ($poll_got) = @_; |
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13 | ... |
12 | ... |
14 | }); |
13 | }); |
15 | |
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16 | * only one io watcher per $fh and $poll type is allowed (i.e. on a socket |
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17 | you can have one r + one w or one rw watcher, not any more (limitation by |
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18 | Tk). |
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19 | |
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20 | * the C<$poll_got> passed to the handler needs to be checked by looking |
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21 | for single characters (e.g. with a regex), as it can contain more event |
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22 | types than were requested (e.g. a 'w' watcher might generate 'rw' events, |
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23 | limitation by Glib). |
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24 | |
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25 | * AnyEvent will keep filehandles alive, so as long as the watcher exists, |
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26 | the filehandle exists. |
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27 | |
14 | |
28 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
29 | ... |
16 | ... |
30 | }); |
17 | }); |
31 | |
18 | |
32 | * io and time watchers get canceled whenever $w is destroyed, so keep a copy |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
33 | |
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34 | * timers can only be used once and must be recreated for repeated |
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35 | operation (limitation by Glib and Tk). |
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36 | |
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37 | my $w = AnyEvent->condvar; # kind of main loop replacement |
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38 | $w->wait; # enters main loop till $condvar gets ->broadcast |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
39 | $w->broadcast; # wake up current and all future wait's |
21 | $w->broadcast; # wake up current and all future wait's |
40 | |
22 | |
41 | * condvars are used to give blocking behaviour when neccessary. Create |
23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
42 | a condvar for any "request" or "event" your module might create, C<< |
24 | |
43 | ->broadcast >> it when the event happens and provide a function that calls |
25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
44 | C<< ->wait >> for it. See the examples below. |
26 | nowadays. So what is different about AnyEvent? |
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27 | |
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28 | Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of |
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29 | policy> and AnyEvent is I<small and efficient>. |
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30 | |
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31 | First and foremost, I<AnyEvent is not an event model> itself, it only |
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32 | interfaces to whatever event model the main program happens to use in a |
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33 | pragmatic way. For event models and certain classes of immortals alike, |
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34 | the statement "there can only be one" is a bitter reality: In general, |
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35 | only one event loop can be active at the same time in a process. AnyEvent |
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36 | helps hiding the differences between those event loops. |
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37 | |
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38 | The goal of AnyEvent is to offer module authors the ability to do event |
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39 | programming (waiting for I/O or timer events) without subscribing to a |
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40 | religion, a way of living, and most importantly: without forcing your |
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41 | module users into the same thing by forcing them to use the same event |
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42 | model you use. |
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43 | |
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44 | For modules like POE or IO::Async (which is a total misnomer as it is |
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45 | actually doing all I/O I<synchronously>...), using them in your module is |
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46 | like joining a cult: After you joined, you are dependent on them and you |
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47 | cannot use anything else, as it is simply incompatible to everything that |
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48 | isn't itself. What's worse, all the potential users of your module are |
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49 | I<also> forced to use the same event loop you use. |
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50 | |
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51 | AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works |
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52 | fine. AnyEvent + Tk works fine etc. etc. but none of these work together |
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53 | with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if |
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54 | your module uses one of those, every user of your module has to use it, |
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55 | too. But if your module uses AnyEvent, it works transparently with all |
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56 | event models it supports (including stuff like POE and IO::Async, as long |
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57 | as those use one of the supported event loops. It is trivial to add new |
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58 | event loops to AnyEvent, too, so it is future-proof). |
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59 | |
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60 | In addition to being free of having to use I<the one and only true event |
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61 | model>, AnyEvent also is free of bloat and policy: with POE or similar |
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62 | modules, you get an enourmous amount of code and strict rules you have to |
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63 | follow. AnyEvent, on the other hand, is lean and up to the point, by only |
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64 | offering the functionality that is necessary, in as thin as a wrapper as |
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65 | technically possible. |
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66 | |
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67 | Of course, if you want lots of policy (this can arguably be somewhat |
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68 | useful) and you want to force your users to use the one and only event |
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69 | model, you should I<not> use this module. |
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70 | |
45 | |
71 | |
46 | =head1 DESCRIPTION |
72 | =head1 DESCRIPTION |
47 | |
73 | |
48 | L<AnyEvent> provides an identical interface to multiple event loops. This |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
49 | allows module authors to utilizy an event loop without forcing module |
75 | allows module authors to utilise an event loop without forcing module |
50 | users to use the same event loop (as only a single event loop can coexist |
76 | users to use the same event loop (as only a single event loop can coexist |
51 | peacefully at any one time). |
77 | peacefully at any one time). |
52 | |
78 | |
53 | The interface itself is vaguely similar but not identical to the Event |
79 | The interface itself is vaguely similar, but not identical to the L<Event> |
54 | module. |
80 | module. |
55 | |
81 | |
56 | On the first call of any method, the module tries to detect the currently |
82 | During the first call of any watcher-creation method, the module tries |
57 | loaded event loop by probing wether any of the following modules is |
83 | to detect the currently loaded event loop by probing whether one of |
58 | loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is |
84 | the following modules is already loaded: L<Coro::EV>, L<Coro::Event>, |
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85 | L<EV>, L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>. The first one |
59 | used. If none is found, the module tries to load these modules in the |
86 | found is used. If none are found, the module tries to load these modules |
60 | order given. The first one that could be successfully loaded will be |
87 | (excluding Event::Lib and Qt) in the order given. The first one that can |
61 | used. If still none could be found, it will issue an error. |
88 | be successfully loaded will be used. If, after this, still none could be |
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89 | found, AnyEvent will fall back to a pure-perl event loop, which is not |
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90 | very efficient, but should work everywhere. |
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91 | |
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92 | Because AnyEvent first checks for modules that are already loaded, loading |
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93 | an event model explicitly before first using AnyEvent will likely make |
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94 | that model the default. For example: |
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95 | |
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96 | use Tk; |
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97 | use AnyEvent; |
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98 | |
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99 | # .. AnyEvent will likely default to Tk |
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100 | |
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101 | The I<likely> means that, if any module loads another event model and |
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102 | starts using it, all bets are off. Maybe you should tell their authors to |
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103 | use AnyEvent so their modules work together with others seamlessly... |
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104 | |
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105 | The pure-perl implementation of AnyEvent is called |
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106 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
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107 | explicitly. |
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108 | |
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109 | =head1 WATCHERS |
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110 | |
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111 | AnyEvent has the central concept of a I<watcher>, which is an object that |
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112 | stores relevant data for each kind of event you are waiting for, such as |
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113 | the callback to call, the filehandle to watch, etc. |
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114 | |
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115 | These watchers are normal Perl objects with normal Perl lifetime. After |
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116 | creating a watcher it will immediately "watch" for events and invoke the |
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117 | callback when the event occurs (of course, only when the event model |
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118 | is in control). |
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119 | |
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120 | To disable the watcher you have to destroy it (e.g. by setting the |
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121 | variable you store it in to C<undef> or otherwise deleting all references |
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122 | to it). |
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123 | |
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124 | All watchers are created by calling a method on the C<AnyEvent> class. |
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125 | |
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126 | Many watchers either are used with "recursion" (repeating timers for |
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127 | example), or need to refer to their watcher object in other ways. |
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128 | |
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129 | An any way to achieve that is this pattern: |
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130 | |
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131 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
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132 | # you can use $w here, for example to undef it |
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133 | undef $w; |
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134 | }); |
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135 | |
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136 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
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137 | my variables are only visible after the statement in which they are |
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138 | declared. |
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139 | |
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140 | =head2 IO WATCHERS |
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141 | |
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142 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
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143 | with the following mandatory key-value pairs as arguments: |
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144 | |
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145 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
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146 | events. C<poll> must be a string that is either C<r> or C<w>, which |
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147 | creates a watcher waiting for "r"eadable or "w"ritable events, |
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148 | respectively. C<cb> is the callback to invoke each time the file handle |
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149 | becomes ready. |
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150 | |
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151 | As long as the I/O watcher exists it will keep the file descriptor or a |
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152 | copy of it alive/open. |
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153 | |
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154 | It is not allowed to close a file handle as long as any watcher is active |
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155 | on the underlying file descriptor. |
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156 | |
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157 | Some event loops issue spurious readyness notifications, so you should |
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158 | always use non-blocking calls when reading/writing from/to your file |
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159 | handles. |
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160 | |
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161 | Example: |
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162 | |
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163 | # wait for readability of STDIN, then read a line and disable the watcher |
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164 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
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165 | chomp (my $input = <STDIN>); |
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166 | warn "read: $input\n"; |
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167 | undef $w; |
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168 | }); |
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169 | |
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170 | =head2 TIME WATCHERS |
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171 | |
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172 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
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173 | method with the following mandatory arguments: |
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174 | |
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175 | C<after> specifies after how many seconds (fractional values are |
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176 | supported) should the timer activate. C<cb> the callback to invoke in that |
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177 | case. |
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178 | |
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179 | The timer callback will be invoked at most once: if you want a repeating |
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180 | timer you have to create a new watcher (this is a limitation by both Tk |
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181 | and Glib). |
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182 | |
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183 | Example: |
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184 | |
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185 | # fire an event after 7.7 seconds |
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186 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
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187 | warn "timeout\n"; |
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188 | }); |
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189 | |
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190 | # to cancel the timer: |
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191 | undef $w; |
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192 | |
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193 | Example 2: |
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194 | |
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195 | # fire an event after 0.5 seconds, then roughly every second |
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196 | my $w; |
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197 | |
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198 | my $cb = sub { |
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199 | # cancel the old timer while creating a new one |
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200 | $w = AnyEvent->timer (after => 1, cb => $cb); |
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201 | }; |
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202 | |
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203 | # start the "loop" by creating the first watcher |
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204 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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205 | |
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206 | =head3 TIMING ISSUES |
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207 | |
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208 | There are two ways to handle timers: based on real time (relative, "fire |
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209 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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210 | o'clock"). |
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211 | |
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212 | While most event loops expect timers to specified in a relative way, they |
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213 | use absolute time internally. This makes a difference when your clock |
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214 | "jumps", for example, when ntp decides to set your clock backwards from |
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215 | the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to |
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216 | fire "after" a second might actually take six years to finally fire. |
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217 | |
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218 | AnyEvent cannot compensate for this. The only event loop that is conscious |
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219 | about these issues is L<EV>, which offers both relative (ev_timer, based |
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220 | on true relative time) and absolute (ev_periodic, based on wallclock time) |
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221 | timers. |
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222 | |
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223 | AnyEvent always prefers relative timers, if available, matching the |
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224 | AnyEvent API. |
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225 | |
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226 | =head2 SIGNAL WATCHERS |
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227 | |
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228 | You can watch for signals using a signal watcher, C<signal> is the signal |
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229 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
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230 | be invoked whenever a signal occurs. |
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231 | |
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232 | Multiple signal occurances can be clumped together into one callback |
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233 | invocation, and callback invocation will be synchronous. synchronous means |
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234 | that it might take a while until the signal gets handled by the process, |
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235 | but it is guarenteed not to interrupt any other callbacks. |
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236 | |
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237 | The main advantage of using these watchers is that you can share a signal |
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238 | between multiple watchers. |
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239 | |
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240 | This watcher might use C<%SIG>, so programs overwriting those signals |
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241 | directly will likely not work correctly. |
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242 | |
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243 | Example: exit on SIGINT |
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244 | |
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245 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
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246 | |
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247 | =head2 CHILD PROCESS WATCHERS |
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248 | |
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249 | You can also watch on a child process exit and catch its exit status. |
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250 | |
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251 | The child process is specified by the C<pid> argument (if set to C<0>, it |
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252 | watches for any child process exit). The watcher will trigger as often |
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253 | as status change for the child are received. This works by installing a |
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254 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
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255 | and exit status (as returned by waitpid). |
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256 | |
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257 | Example: wait for pid 1333 |
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258 | |
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259 | my $w = AnyEvent->child ( |
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260 | pid => 1333, |
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261 | cb => sub { |
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262 | my ($pid, $status) = @_; |
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263 | warn "pid $pid exited with status $status"; |
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264 | }, |
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265 | ); |
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266 | |
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267 | =head2 CONDITION VARIABLES |
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268 | |
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269 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
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270 | method without any arguments. |
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271 | |
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272 | A condition variable waits for a condition - precisely that the C<< |
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273 | ->broadcast >> method has been called. |
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274 | |
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275 | They are very useful to signal that a condition has been fulfilled, for |
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276 | example, if you write a module that does asynchronous http requests, |
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277 | then a condition variable would be the ideal candidate to signal the |
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278 | availability of results. |
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279 | |
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280 | You can also use condition variables to block your main program until |
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281 | an event occurs - for example, you could C<< ->wait >> in your main |
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282 | program until the user clicks the Quit button in your app, which would C<< |
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283 | ->broadcast >> the "quit" event. |
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284 | |
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285 | Note that condition variables recurse into the event loop - if you have |
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286 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
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287 | lose. Therefore, condition variables are good to export to your caller, but |
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288 | you should avoid making a blocking wait yourself, at least in callbacks, |
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289 | as this asks for trouble. |
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290 | |
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291 | This object has two methods: |
62 | |
292 | |
63 | =over 4 |
293 | =over 4 |
64 | |
294 | |
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295 | =item $cv->wait |
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296 | |
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297 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
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298 | called on c<$cv>, while servicing other watchers normally. |
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299 | |
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300 | You can only wait once on a condition - additional calls will return |
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301 | immediately. |
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302 | |
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303 | Not all event models support a blocking wait - some die in that case |
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304 | (programs might want to do that to stay interactive), so I<if you are |
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305 | using this from a module, never require a blocking wait>, but let the |
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306 | caller decide whether the call will block or not (for example, by coupling |
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307 | condition variables with some kind of request results and supporting |
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308 | callbacks so the caller knows that getting the result will not block, |
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309 | while still suppporting blocking waits if the caller so desires). |
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310 | |
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311 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
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312 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
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313 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
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314 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
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315 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
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316 | from different coroutines, however). |
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317 | |
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318 | =item $cv->broadcast |
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319 | |
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320 | Flag the condition as ready - a running C<< ->wait >> and all further |
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321 | calls to C<wait> will (eventually) return after this method has been |
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322 | called. If nobody is waiting the broadcast will be remembered.. |
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323 | |
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324 | =back |
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325 | |
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326 | Example: |
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327 | |
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328 | # wait till the result is ready |
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329 | my $result_ready = AnyEvent->condvar; |
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330 | |
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331 | # do something such as adding a timer |
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332 | # or socket watcher the calls $result_ready->broadcast |
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333 | # when the "result" is ready. |
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334 | # in this case, we simply use a timer: |
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335 | my $w = AnyEvent->timer ( |
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336 | after => 1, |
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337 | cb => sub { $result_ready->broadcast }, |
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338 | ); |
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339 | |
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340 | # this "blocks" (while handling events) till the watcher |
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341 | # calls broadcast |
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342 | $result_ready->wait; |
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343 | |
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344 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
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345 | |
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346 | =over 4 |
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347 | |
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348 | =item $AnyEvent::MODEL |
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349 | |
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350 | Contains C<undef> until the first watcher is being created. Then it |
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351 | contains the event model that is being used, which is the name of the |
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352 | Perl class implementing the model. This class is usually one of the |
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353 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
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354 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
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355 | |
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356 | The known classes so far are: |
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357 | |
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358 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
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359 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
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360 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
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361 | AnyEvent::Impl::Event based on Event, second best choice. |
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362 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
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363 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
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364 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
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365 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
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366 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
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367 | |
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368 | =item AnyEvent::detect |
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369 | |
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370 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
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371 | if necessary. You should only call this function right before you would |
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372 | have created an AnyEvent watcher anyway, that is, as late as possible at |
|
|
373 | runtime. |
|
|
374 | |
|
|
375 | =back |
|
|
376 | |
|
|
377 | =head1 WHAT TO DO IN A MODULE |
|
|
378 | |
|
|
379 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
|
|
380 | freely, but you should not load a specific event module or rely on it. |
|
|
381 | |
|
|
382 | Be careful when you create watchers in the module body - AnyEvent will |
|
|
383 | decide which event module to use as soon as the first method is called, so |
|
|
384 | by calling AnyEvent in your module body you force the user of your module |
|
|
385 | to load the event module first. |
|
|
386 | |
|
|
387 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
|
|
388 | the C<< ->broadcast >> method has been called on it already. This is |
|
|
389 | because it will stall the whole program, and the whole point of using |
|
|
390 | events is to stay interactive. |
|
|
391 | |
|
|
392 | It is fine, however, to call C<< ->wait >> when the user of your module |
|
|
393 | requests it (i.e. if you create a http request object ad have a method |
|
|
394 | called C<results> that returns the results, it should call C<< ->wait >> |
|
|
395 | freely, as the user of your module knows what she is doing. always). |
|
|
396 | |
|
|
397 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
|
|
398 | |
|
|
399 | There will always be a single main program - the only place that should |
|
|
400 | dictate which event model to use. |
|
|
401 | |
|
|
402 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
|
|
403 | do anything special (it does not need to be event-based) and let AnyEvent |
|
|
404 | decide which implementation to chose if some module relies on it. |
|
|
405 | |
|
|
406 | If the main program relies on a specific event model. For example, in |
|
|
407 | Gtk2 programs you have to rely on the Glib module. You should load the |
|
|
408 | event module before loading AnyEvent or any module that uses it: generally |
|
|
409 | speaking, you should load it as early as possible. The reason is that |
|
|
410 | modules might create watchers when they are loaded, and AnyEvent will |
|
|
411 | decide on the event model to use as soon as it creates watchers, and it |
|
|
412 | might chose the wrong one unless you load the correct one yourself. |
|
|
413 | |
|
|
414 | You can chose to use a rather inefficient pure-perl implementation by |
|
|
415 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
|
|
416 | behaviour everywhere, but letting AnyEvent chose is generally better. |
|
|
417 | |
65 | =cut |
418 | =cut |
66 | |
419 | |
67 | package AnyEvent; |
420 | package AnyEvent; |
68 | |
421 | |
69 | no warnings; |
422 | no warnings; |
70 | use strict 'vars'; |
423 | use strict; |
|
|
424 | |
71 | use Carp; |
425 | use Carp; |
72 | |
426 | |
73 | our $VERSION = '1.01'; |
427 | our $VERSION = '3.2'; |
74 | our $MODEL; |
428 | our $MODEL; |
75 | |
429 | |
76 | our $AUTOLOAD; |
430 | our $AUTOLOAD; |
77 | our @ISA; |
431 | our @ISA; |
78 | |
432 | |
79 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
433 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
80 | |
434 | |
81 | our @REGISTRY; |
435 | our @REGISTRY; |
82 | |
436 | |
83 | my @models = ( |
437 | my @models = ( |
|
|
438 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
84 | [Coro::Event:: => AnyEvent::Impl::Coro::], |
439 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
|
|
440 | [EV:: => AnyEvent::Impl::EV::], |
85 | [Event:: => AnyEvent::Impl::Event::], |
441 | [Event:: => AnyEvent::Impl::Event::], |
86 | [Glib:: => AnyEvent::Impl::Glib::], |
442 | [Glib:: => AnyEvent::Impl::Glib::], |
87 | [Tk:: => AnyEvent::Impl::Tk::], |
443 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
444 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
88 | ); |
445 | ); |
|
|
446 | my @models_detect = ( |
|
|
447 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
|
|
448 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
|
|
449 | ); |
89 | |
450 | |
90 | our %method = map +($_ => 1), qw(io timer condvar broadcast wait cancel DESTROY); |
451 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
91 | |
452 | |
92 | sub AUTOLOAD { |
453 | sub detect() { |
93 | $AUTOLOAD =~ s/.*://; |
|
|
94 | |
|
|
95 | $method{$AUTOLOAD} |
|
|
96 | or croak "$AUTOLOAD: not a valid method for AnyEvent objects"; |
|
|
97 | |
|
|
98 | unless ($MODEL) { |
454 | unless ($MODEL) { |
|
|
455 | no strict 'refs'; |
|
|
456 | |
|
|
457 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
|
|
458 | my $model = "AnyEvent::Impl::$1"; |
|
|
459 | if (eval "require $model") { |
|
|
460 | $MODEL = $model; |
|
|
461 | warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; |
|
|
462 | } |
|
|
463 | } |
|
|
464 | |
99 | # check for already loaded models |
465 | # check for already loaded models |
|
|
466 | unless ($MODEL) { |
100 | for (@REGISTRY, @models) { |
467 | for (@REGISTRY, @models, @models_detect) { |
101 | my ($package, $model) = @$_; |
468 | my ($package, $model) = @$_; |
102 | if (${"$package\::VERSION"} > 0) { |
469 | if (${"$package\::VERSION"} > 0) { |
103 | if (eval "require $model") { |
470 | if (eval "require $model") { |
104 | $MODEL = $model; |
471 | $MODEL = $model; |
105 | warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1; |
472 | warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; |
106 | last; |
473 | last; |
|
|
474 | } |
107 | } |
475 | } |
108 | } |
476 | } |
|
|
477 | |
|
|
478 | unless ($MODEL) { |
|
|
479 | # try to load a model |
|
|
480 | |
|
|
481 | for (@REGISTRY, @models) { |
|
|
482 | my ($package, $model) = @$_; |
|
|
483 | if (eval "require $package" |
|
|
484 | and ${"$package\::VERSION"} > 0 |
|
|
485 | and eval "require $model") { |
|
|
486 | $MODEL = $model; |
|
|
487 | warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; |
|
|
488 | last; |
|
|
489 | } |
|
|
490 | } |
|
|
491 | |
|
|
492 | $MODEL |
|
|
493 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib."; |
|
|
494 | } |
109 | } |
495 | } |
110 | |
496 | |
111 | unless ($MODEL) { |
497 | unshift @ISA, $MODEL; |
112 | # try to load a model |
498 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
113 | |
|
|
114 | for (@REGISTRY, @models) { |
|
|
115 | my ($package, $model) = @$_; |
|
|
116 | if (eval "require $model") { |
|
|
117 | $MODEL = $model; |
|
|
118 | warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1; |
|
|
119 | last; |
|
|
120 | } |
|
|
121 | } |
|
|
122 | |
|
|
123 | $MODEL |
|
|
124 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk."; |
|
|
125 | } |
|
|
126 | } |
499 | } |
127 | |
500 | |
128 | @ISA = $MODEL; |
501 | $MODEL |
|
|
502 | } |
|
|
503 | |
|
|
504 | sub AUTOLOAD { |
|
|
505 | (my $func = $AUTOLOAD) =~ s/.*://; |
|
|
506 | |
|
|
507 | $method{$func} |
|
|
508 | or croak "$func: not a valid method for AnyEvent objects"; |
|
|
509 | |
|
|
510 | detect unless $MODEL; |
129 | |
511 | |
130 | my $class = shift; |
512 | my $class = shift; |
131 | $class->$AUTOLOAD (@_); |
513 | $class->$func (@_); |
132 | } |
514 | } |
133 | |
515 | |
134 | =back |
516 | package AnyEvent::Base; |
|
|
517 | |
|
|
518 | # default implementation for ->condvar, ->wait, ->broadcast |
|
|
519 | |
|
|
520 | sub condvar { |
|
|
521 | bless \my $flag, "AnyEvent::Base::CondVar" |
|
|
522 | } |
|
|
523 | |
|
|
524 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
525 | ${$_[0]}++; |
|
|
526 | } |
|
|
527 | |
|
|
528 | sub AnyEvent::Base::CondVar::wait { |
|
|
529 | AnyEvent->one_event while !${$_[0]}; |
|
|
530 | } |
|
|
531 | |
|
|
532 | # default implementation for ->signal |
|
|
533 | |
|
|
534 | our %SIG_CB; |
|
|
535 | |
|
|
536 | sub signal { |
|
|
537 | my (undef, %arg) = @_; |
|
|
538 | |
|
|
539 | my $signal = uc $arg{signal} |
|
|
540 | or Carp::croak "required option 'signal' is missing"; |
|
|
541 | |
|
|
542 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
|
|
543 | $SIG{$signal} ||= sub { |
|
|
544 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
|
|
545 | }; |
|
|
546 | |
|
|
547 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
|
|
548 | } |
|
|
549 | |
|
|
550 | sub AnyEvent::Base::Signal::DESTROY { |
|
|
551 | my ($signal, $cb) = @{$_[0]}; |
|
|
552 | |
|
|
553 | delete $SIG_CB{$signal}{$cb}; |
|
|
554 | |
|
|
555 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
|
|
556 | } |
|
|
557 | |
|
|
558 | # default implementation for ->child |
|
|
559 | |
|
|
560 | our %PID_CB; |
|
|
561 | our $CHLD_W; |
|
|
562 | our $CHLD_DELAY_W; |
|
|
563 | our $PID_IDLE; |
|
|
564 | our $WNOHANG; |
|
|
565 | |
|
|
566 | sub _child_wait { |
|
|
567 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
|
|
568 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
|
|
569 | (values %{ $PID_CB{0} || {} }); |
|
|
570 | } |
|
|
571 | |
|
|
572 | undef $PID_IDLE; |
|
|
573 | } |
|
|
574 | |
|
|
575 | sub _sigchld { |
|
|
576 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
577 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
578 | undef $CHLD_DELAY_W; |
|
|
579 | &_child_wait; |
|
|
580 | }); |
|
|
581 | } |
|
|
582 | |
|
|
583 | sub child { |
|
|
584 | my (undef, %arg) = @_; |
|
|
585 | |
|
|
586 | defined (my $pid = $arg{pid} + 0) |
|
|
587 | or Carp::croak "required option 'pid' is missing"; |
|
|
588 | |
|
|
589 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
|
|
590 | |
|
|
591 | unless ($WNOHANG) { |
|
|
592 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
|
|
593 | } |
|
|
594 | |
|
|
595 | unless ($CHLD_W) { |
|
|
596 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
|
|
597 | # child could be a zombie already, so make at least one round |
|
|
598 | &_sigchld; |
|
|
599 | } |
|
|
600 | |
|
|
601 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
|
|
602 | } |
|
|
603 | |
|
|
604 | sub AnyEvent::Base::Child::DESTROY { |
|
|
605 | my ($pid, $cb) = @{$_[0]}; |
|
|
606 | |
|
|
607 | delete $PID_CB{$pid}{$cb}; |
|
|
608 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
|
|
609 | |
|
|
610 | undef $CHLD_W unless keys %PID_CB; |
|
|
611 | } |
135 | |
612 | |
136 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
613 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
|
|
614 | |
|
|
615 | This is an advanced topic that you do not normally need to use AnyEvent in |
|
|
616 | a module. This section is only of use to event loop authors who want to |
|
|
617 | provide AnyEvent compatibility. |
137 | |
618 | |
138 | If you need to support another event library which isn't directly |
619 | If you need to support another event library which isn't directly |
139 | supported by AnyEvent, you can supply your own interface to it by |
620 | supported by AnyEvent, you can supply your own interface to it by |
140 | pushing, before the first watch gets created, the package name of |
621 | pushing, before the first watcher gets created, the package name of |
141 | the event module and the package name of the interface to use onto |
622 | the event module and the package name of the interface to use onto |
142 | C<@AnyEvent::REGISTRY>. You can do that before and even without loading |
623 | C<@AnyEvent::REGISTRY>. You can do that before and even without loading |
143 | AnyEvent. |
624 | AnyEvent, so it is reasonably cheap. |
144 | |
625 | |
145 | Example: |
626 | Example: |
146 | |
627 | |
147 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
628 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
148 | |
629 | |
149 | This tells AnyEvent to (literally) use the C<urxvt::anyevent::> module |
630 | This tells AnyEvent to (literally) use the C<urxvt::anyevent::> |
150 | when it finds the C<urxvt> module is loaded. When AnyEvent is loaded and |
631 | package/class when it finds the C<urxvt> package/module is already loaded. |
151 | requested to find a suitable event model, it will first check for the |
|
|
152 | urxvt module. |
|
|
153 | |
632 | |
|
|
633 | When AnyEvent is loaded and asked to find a suitable event model, it |
|
|
634 | will first check for the presence of urxvt by trying to C<use> the |
|
|
635 | C<urxvt::anyevent> module. |
|
|
636 | |
|
|
637 | The class should provide implementations for all watcher types. See |
|
|
638 | L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code) |
|
|
639 | and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to |
|
|
640 | see the sources. |
|
|
641 | |
|
|
642 | If you don't provide C<signal> and C<child> watchers than AnyEvent will |
|
|
643 | provide suitable (hopefully) replacements. |
|
|
644 | |
154 | The above isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) uses |
645 | The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) |
155 | the above line exactly. An interface isn't included in AnyEvent |
646 | terminal emulator uses the above line as-is. An interface isn't included |
156 | because it doesn't make sense outside the embedded interpreter inside |
647 | in AnyEvent because it doesn't make sense outside the embedded interpreter |
157 | I<rxvt-unicode>, and it is updated and maintained as part of the |
648 | inside I<rxvt-unicode>, and it is updated and maintained as part of the |
158 | I<rxvt-unicode> distribution. |
649 | I<rxvt-unicode> distribution. |
159 | |
650 | |
|
|
651 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
|
|
652 | condition variables: code blocking while waiting for a condition will |
|
|
653 | C<die>. This still works with most modules/usages, and blocking calls must |
|
|
654 | not be done in an interactive application, so it makes sense. |
|
|
655 | |
160 | =head1 ENVIRONMENT VARIABLES |
656 | =head1 ENVIRONMENT VARIABLES |
161 | |
657 | |
162 | The following environment variables are used by this module: |
658 | The following environment variables are used by this module: |
163 | |
659 | |
164 | C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, reports which event |
660 | =over 4 |
165 | model gets used. |
|
|
166 | |
661 | |
|
|
662 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
663 | |
|
|
664 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
665 | model it chooses. |
|
|
666 | |
|
|
667 | =item C<PERL_ANYEVENT_MODEL> |
|
|
668 | |
|
|
669 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
670 | autodetection and -probing kicks in. It must be a string consisting |
|
|
671 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
672 | and the resulting module name is loaded and if the load was successful, |
|
|
673 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
674 | autodetection and -probing. |
|
|
675 | |
|
|
676 | This functionality might change in future versions. |
|
|
677 | |
|
|
678 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
679 | could start your program like this: |
|
|
680 | |
|
|
681 | PERL_ANYEVENT_MODEL=Perl perl ... |
|
|
682 | |
|
|
683 | =back |
|
|
684 | |
167 | =head1 EXAMPLE |
685 | =head1 EXAMPLE PROGRAM |
168 | |
686 | |
169 | The following program uses an io watcher to read data from stdin, a timer |
687 | The following program uses an IO watcher to read data from STDIN, a timer |
170 | to display a message once per second, and a condvar to exit the program |
688 | to display a message once per second, and a condition variable to quit the |
171 | when the user enters quit: |
689 | program when the user enters quit: |
172 | |
690 | |
173 | use AnyEvent; |
691 | use AnyEvent; |
174 | |
692 | |
175 | my $cv = AnyEvent->condvar; |
693 | my $cv = AnyEvent->condvar; |
176 | |
694 | |
177 | my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
695 | my $io_watcher = AnyEvent->io ( |
|
|
696 | fh => \*STDIN, |
|
|
697 | poll => 'r', |
|
|
698 | cb => sub { |
178 | warn "io event <$_[0]>\n"; # will always output <r> |
699 | warn "io event <$_[0]>\n"; # will always output <r> |
179 | chomp (my $input = <STDIN>); # read a line |
700 | chomp (my $input = <STDIN>); # read a line |
180 | warn "read: $input\n"; # output what has been read |
701 | warn "read: $input\n"; # output what has been read |
181 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
702 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
|
|
703 | }, |
182 | }); |
704 | ); |
183 | |
705 | |
184 | my $time_watcher; # can only be used once |
706 | my $time_watcher; # can only be used once |
185 | |
707 | |
186 | sub new_timer { |
708 | sub new_timer { |
187 | $timer = AnyEvent->timer (after => 1, cb => sub { |
709 | $timer = AnyEvent->timer (after => 1, cb => sub { |
… | |
… | |
269 | $txn->{finished}->wait; |
791 | $txn->{finished}->wait; |
270 | return $txn->{result}; |
792 | return $txn->{result}; |
271 | |
793 | |
272 | The actual code goes further and collects all errors (C<die>s, exceptions) |
794 | The actual code goes further and collects all errors (C<die>s, exceptions) |
273 | that occured during request processing. The C<result> method detects |
795 | that occured during request processing. The C<result> method detects |
274 | wether an exception as thrown (it is stored inside the $txn object) |
796 | whether an exception as thrown (it is stored inside the $txn object) |
275 | and just throws the exception, which means connection errors and other |
797 | and just throws the exception, which means connection errors and other |
276 | problems get reported tot he code that tries to use the result, not in a |
798 | problems get reported tot he code that tries to use the result, not in a |
277 | random callback. |
799 | random callback. |
278 | |
800 | |
279 | All of this enables the following usage styles: |
801 | All of this enables the following usage styles: |
280 | |
802 | |
281 | 1. Blocking: |
803 | 1. Blocking: |
282 | |
804 | |
283 | my $data = $fcp->client_get ($url); |
805 | my $data = $fcp->client_get ($url); |
284 | |
806 | |
285 | 2. Blocking, but parallelizing: |
807 | 2. Blocking, but running in parallel: |
286 | |
808 | |
287 | my @datas = map $_->result, |
809 | my @datas = map $_->result, |
288 | map $fcp->txn_client_get ($_), |
810 | map $fcp->txn_client_get ($_), |
289 | @urls; |
811 | @urls; |
290 | |
812 | |
291 | Both blocking examples work without the module user having to know |
813 | Both blocking examples work without the module user having to know |
292 | anything about events. |
814 | anything about events. |
293 | |
815 | |
294 | 3a. Event-based in a main program, using any support Event module: |
816 | 3a. Event-based in a main program, using any supported event module: |
295 | |
817 | |
296 | use Event; |
818 | use EV; |
297 | |
819 | |
298 | $fcp->txn_client_get ($url)->cb (sub { |
820 | $fcp->txn_client_get ($url)->cb (sub { |
299 | my $txn = shift; |
821 | my $txn = shift; |
300 | my $data = $txn->result; |
822 | my $data = $txn->result; |
301 | ... |
823 | ... |
302 | }); |
824 | }); |
303 | |
825 | |
304 | Event::loop; |
826 | EV::loop; |
305 | |
827 | |
306 | 3b. The module user could use AnyEvent, too: |
828 | 3b. The module user could use AnyEvent, too: |
307 | |
829 | |
308 | use AnyEvent; |
830 | use AnyEvent; |
309 | |
831 | |
… | |
… | |
314 | $quit->broadcast; |
836 | $quit->broadcast; |
315 | }); |
837 | }); |
316 | |
838 | |
317 | $quit->wait; |
839 | $quit->wait; |
318 | |
840 | |
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841 | =head1 FORK |
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842 | |
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843 | Most event libraries are not fork-safe. The ones who are usually are |
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844 | because they are so inefficient. Only L<EV> is fully fork-aware. |
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845 | |
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846 | If you have to fork, you must either do so I<before> creating your first |
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847 | watcher OR you must not use AnyEvent at all in the child. |
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848 | |
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849 | =head1 SECURITY CONSIDERATIONS |
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850 | |
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851 | AnyEvent can be forced to load any event model via |
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852 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to |
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853 | execute arbitrary code or directly gain access, it can easily be used to |
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854 | make the program hang or malfunction in subtle ways, as AnyEvent watchers |
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855 | will not be active when the program uses a different event model than |
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856 | specified in the variable. |
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857 | |
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858 | You can make AnyEvent completely ignore this variable by deleting it |
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859 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
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860 | |
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861 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
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862 | |
|
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863 | use AnyEvent; |
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864 | |
319 | =head1 SEE ALSO |
865 | =head1 SEE ALSO |
320 | |
866 | |
321 | Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>. |
867 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
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868 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
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869 | L<Event::Lib>, L<Qt>. |
322 | |
870 | |
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871 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
323 | Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>. |
872 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
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873 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
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874 | L<AnyEvent::Impl::Qt>. |
324 | |
875 | |
325 | Nontrivial usage example: L<Net::FCP>. |
876 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
326 | |
877 | |
327 | =head1 |
878 | =head1 AUTHOR |
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879 | |
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880 | Marc Lehmann <schmorp@schmorp.de> |
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881 | http://home.schmorp.de/ |
328 | |
882 | |
329 | =cut |
883 | =cut |
330 | |
884 | |
331 | 1 |
885 | 1 |
332 | |
886 | |