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->timer (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 | }); |
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14 | |
15 | my $w = AnyEvent->io (after => $seconds, cb => sub { |
15 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
16 | ... |
16 | ... |
17 | }); |
17 | }); |
18 | |
18 | |
19 | # watchers get canceled whenever $w is destroyed |
19 | my $w = AnyEvent->condvar; # stores whether a condition was flagged |
20 | # only one watcher per $fh and $poll type is allowed |
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21 | # (i.e. on a socket you cna have one r + one w or one rw |
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22 | # watcher, not any more. |
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23 | # timers can only be used once |
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24 | |
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25 | my $w = AnyEvent->condvar; # kind of main loop replacement |
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26 | # can only be used once |
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27 | $w->wait; # enters main loop till $condvar gets ->send |
20 | $w->wait; # enters "main loop" till $condvar gets ->broadcast |
28 | $w->broadcast; # wake up waiting and future wait's |
21 | $w->broadcast; # wake up current and all future wait's |
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22 | |
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23 | =head1 WHY YOU SHOULD USE THIS MODULE (OR NOT) |
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24 | |
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25 | Glib, POE, IO::Async, Event... CPAN offers event models by the dozen |
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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 | |
29 | |
71 | |
30 | =head1 DESCRIPTION |
72 | =head1 DESCRIPTION |
31 | |
73 | |
32 | L<AnyEvent> provides an identical interface to multiple event loops. This |
74 | L<AnyEvent> provides an identical interface to multiple event loops. This |
33 | allows module authors to utilizy an event loop without forcing module |
75 | allows module authors to utilise an event loop without forcing module |
34 | 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 |
35 | peacefully at any one time). |
77 | peacefully at any one time). |
36 | |
78 | |
37 | 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> |
38 | module. |
80 | module. |
39 | |
81 | |
40 | 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 |
41 | 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 the |
42 | loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is |
84 | following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>, |
43 | used. If none is found, the module tries to load these modules in the |
85 | L<Event>, L<Glib>, L<Tk>. The first one found is used. If none are found, |
44 | order given. The first one that could be successfully loaded will be |
86 | the module tries to load these modules in the stated order. The first one |
45 | used. If still none could be found, it will issue an error. |
87 | that can be successfully loaded will be used. If, after this, still none |
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88 | could be found, AnyEvent will fall back to a pure-perl event loop, which |
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89 | is not very efficient, but should work everywhere. |
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90 | |
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91 | Because AnyEvent first checks for modules that are already loaded, loading |
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92 | an event model explicitly before first using AnyEvent will likely make |
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93 | that model the default. For example: |
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94 | |
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95 | use Tk; |
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96 | use AnyEvent; |
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97 | |
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98 | # .. AnyEvent will likely default to Tk |
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99 | |
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100 | The I<likely> means that, if any module loads another event model and |
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101 | starts using it, all bets are off. Maybe you should tell their authors to |
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102 | use AnyEvent so their modules work together with others seamlessly... |
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103 | |
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104 | The pure-perl implementation of AnyEvent is called |
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105 | C<AnyEvent::Impl::Perl>. Like other event modules you can load it |
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106 | explicitly. |
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107 | |
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108 | =head1 WATCHERS |
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109 | |
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110 | AnyEvent has the central concept of a I<watcher>, which is an object that |
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111 | stores relevant data for each kind of event you are waiting for, such as |
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112 | the callback to call, the filehandle to watch, etc. |
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113 | |
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114 | These watchers are normal Perl objects with normal Perl lifetime. After |
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115 | creating a watcher it will immediately "watch" for events and invoke the |
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116 | callback when the event occurs (of course, only when the event model |
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117 | is in control). |
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118 | |
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119 | To disable the watcher you have to destroy it (e.g. by setting the |
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120 | variable you store it in to C<undef> or otherwise deleting all references |
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121 | to it). |
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122 | |
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123 | All watchers are created by calling a method on the C<AnyEvent> class. |
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124 | |
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125 | Many watchers either are used with "recursion" (repeating timers for |
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126 | example), or need to refer to their watcher object in other ways. |
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127 | |
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128 | An any way to achieve that is this pattern: |
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129 | |
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130 | my $w; $w = AnyEvent->type (arg => value ..., cb => sub { |
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131 | # you can use $w here, for example to undef it |
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132 | undef $w; |
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133 | }); |
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134 | |
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135 | Note that C<my $w; $w => combination. This is necessary because in Perl, |
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136 | my variables are only visible after the statement in which they are |
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137 | declared. |
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138 | |
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139 | =head2 IO WATCHERS |
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140 | |
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141 | You can create an I/O watcher by calling the C<< AnyEvent->io >> method |
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142 | with the following mandatory key-value pairs as arguments: |
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143 | |
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144 | C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for |
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145 | events. C<poll> must be a string that is either C<r> or C<w>, which |
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146 | creates a watcher waiting for "r"eadable or "w"ritable events, |
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147 | respectively. C<cb> is the callback to invoke each time the file handle |
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148 | becomes ready. |
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149 | |
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150 | As long as the I/O watcher exists it will keep the file descriptor or a |
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151 | copy of it alive/open. |
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152 | |
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153 | It is not allowed to close a file handle as long as any watcher is active |
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154 | on the underlying file descriptor. |
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155 | |
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156 | Some event loops issue spurious readyness notifications, so you should |
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157 | always use non-blocking calls when reading/writing from/to your file |
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158 | handles. |
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159 | |
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160 | Example: |
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161 | |
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162 | # wait for readability of STDIN, then read a line and disable the watcher |
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163 | my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
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164 | chomp (my $input = <STDIN>); |
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165 | warn "read: $input\n"; |
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166 | undef $w; |
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167 | }); |
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168 | |
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169 | =head2 TIME WATCHERS |
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170 | |
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171 | You can create a time watcher by calling the C<< AnyEvent->timer >> |
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172 | method with the following mandatory arguments: |
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173 | |
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174 | C<after> specifies after how many seconds (fractional values are |
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175 | supported) should the timer activate. C<cb> the callback to invoke in that |
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176 | case. |
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177 | |
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178 | The timer callback will be invoked at most once: if you want a repeating |
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179 | timer you have to create a new watcher (this is a limitation by both Tk |
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180 | and Glib). |
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181 | |
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182 | Example: |
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183 | |
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184 | # fire an event after 7.7 seconds |
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185 | my $w = AnyEvent->timer (after => 7.7, cb => sub { |
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186 | warn "timeout\n"; |
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187 | }); |
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188 | |
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189 | # to cancel the timer: |
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190 | undef $w; |
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191 | |
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192 | Example 2: |
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193 | |
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194 | # fire an event after 0.5 seconds, then roughly every second |
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195 | my $w; |
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196 | |
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197 | my $cb = sub { |
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198 | # cancel the old timer while creating a new one |
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199 | $w = AnyEvent->timer (after => 1, cb => $cb); |
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200 | }; |
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201 | |
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202 | # start the "loop" by creating the first watcher |
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203 | $w = AnyEvent->timer (after => 0.5, cb => $cb); |
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204 | |
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205 | =head3 TIMING ISSUES |
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206 | |
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207 | There are two ways to handle timers: based on real time (relative, "fire |
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208 | in 10 seconds") and based on wallclock time (absolute, "fire at 12 |
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209 | o'clock"). |
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210 | |
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211 | While most event loops expect timers to specified in a relative way, they use |
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212 | absolute time internally. This makes a difference when your clock "jumps", |
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213 | for example, when ntp decides to set your clock backwards from the wrong 2014-01-01 to |
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214 | 2008-01-01, a watcher that you created to fire "after" a second might actually take |
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215 | six years to finally fire. |
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216 | |
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217 | AnyEvent cannot compensate for this. The only event loop that is conscious |
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218 | about these issues is L<EV>, which offers both relative (ev_timer) and |
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219 | absolute (ev_periodic) timers. |
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220 | |
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221 | AnyEvent always prefers relative timers, if available, matching the |
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222 | AnyEvent API. |
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223 | |
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224 | =head2 SIGNAL WATCHERS |
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225 | |
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226 | You can watch for signals using a signal watcher, C<signal> is the signal |
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227 | I<name> without any C<SIG> prefix, C<cb> is the Perl callback to |
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228 | be invoked whenever a signal occurs. |
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229 | |
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230 | Multiple signals occurances can be clumped together into one callback |
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231 | invocation, and callback invocation will be synchronous. synchronous means |
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232 | that it might take a while until the signal gets handled by the process, |
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233 | but it is guarenteed not to interrupt any other callbacks. |
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234 | |
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235 | The main advantage of using these watchers is that you can share a signal |
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236 | between multiple watchers. |
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237 | |
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238 | This watcher might use C<%SIG>, so programs overwriting those signals |
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239 | directly will likely not work correctly. |
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240 | |
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241 | Example: exit on SIGINT |
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242 | |
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243 | my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 }); |
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244 | |
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245 | =head2 CHILD PROCESS WATCHERS |
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246 | |
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247 | You can also watch on a child process exit and catch its exit status. |
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248 | |
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249 | The child process is specified by the C<pid> argument (if set to C<0>, it |
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250 | watches for any child process exit). The watcher will trigger as often |
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251 | as status change for the child are received. This works by installing a |
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252 | signal handler for C<SIGCHLD>. The callback will be called with the pid |
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253 | and exit status (as returned by waitpid). |
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254 | |
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255 | Example: wait for pid 1333 |
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256 | |
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257 | my $w = AnyEvent->child ( |
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258 | pid => 1333, |
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259 | cb => sub { |
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260 | my ($pid, $status) = @_; |
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261 | warn "pid $pid exited with status $status"; |
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262 | }, |
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263 | ); |
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264 | |
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265 | =head2 CONDITION VARIABLES |
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266 | |
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267 | Condition variables can be created by calling the C<< AnyEvent->condvar >> |
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268 | method without any arguments. |
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269 | |
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270 | A condition variable waits for a condition - precisely that the C<< |
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271 | ->broadcast >> method has been called. |
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272 | |
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273 | They are very useful to signal that a condition has been fulfilled, for |
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274 | example, if you write a module that does asynchronous http requests, |
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275 | then a condition variable would be the ideal candidate to signal the |
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276 | availability of results. |
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277 | |
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278 | You can also use condition variables to block your main program until |
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279 | an event occurs - for example, you could C<< ->wait >> in your main |
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280 | program until the user clicks the Quit button in your app, which would C<< |
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281 | ->broadcast >> the "quit" event. |
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282 | |
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283 | Note that condition variables recurse into the event loop - if you have |
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284 | two pirces of code that call C<< ->wait >> in a round-robbin fashion, you |
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285 | lose. Therefore, condition variables are good to export to your caller, but |
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286 | you should avoid making a blocking wait yourself, at least in callbacks, |
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287 | as this asks for trouble. |
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288 | |
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289 | This object has two methods: |
46 | |
290 | |
47 | =over 4 |
291 | =over 4 |
48 | |
292 | |
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293 | =item $cv->wait |
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294 | |
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295 | Wait (blocking if necessary) until the C<< ->broadcast >> method has been |
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296 | called on c<$cv>, while servicing other watchers normally. |
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297 | |
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298 | You can only wait once on a condition - additional calls will return |
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299 | immediately. |
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300 | |
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301 | Not all event models support a blocking wait - some die in that case |
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302 | (programs might want to do that to stay interactive), so I<if you are |
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303 | using this from a module, never require a blocking wait>, but let the |
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304 | caller decide whether the call will block or not (for example, by coupling |
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305 | condition variables with some kind of request results and supporting |
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306 | callbacks so the caller knows that getting the result will not block, |
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307 | while still suppporting blocking waits if the caller so desires). |
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308 | |
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309 | Another reason I<never> to C<< ->wait >> in a module is that you cannot |
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310 | sensibly have two C<< ->wait >>'s in parallel, as that would require |
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311 | multiple interpreters or coroutines/threads, none of which C<AnyEvent> |
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312 | can supply (the coroutine-aware backends L<AnyEvent::Impl::CoroEV> and |
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313 | L<AnyEvent::Impl::CoroEvent> explicitly support concurrent C<< ->wait >>'s |
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314 | from different coroutines, however). |
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315 | |
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316 | =item $cv->broadcast |
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317 | |
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318 | Flag the condition as ready - a running C<< ->wait >> and all further |
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319 | calls to C<wait> will (eventually) return after this method has been |
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320 | called. If nobody is waiting the broadcast will be remembered.. |
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321 | |
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322 | =back |
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323 | |
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324 | Example: |
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325 | |
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326 | # wait till the result is ready |
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327 | my $result_ready = AnyEvent->condvar; |
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328 | |
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329 | # do something such as adding a timer |
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330 | # or socket watcher the calls $result_ready->broadcast |
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331 | # when the "result" is ready. |
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332 | # in this case, we simply use a timer: |
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333 | my $w = AnyEvent->timer ( |
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334 | after => 1, |
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335 | cb => sub { $result_ready->broadcast }, |
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336 | ); |
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337 | |
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338 | # this "blocks" (while handling events) till the watcher |
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339 | # calls broadcast |
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340 | $result_ready->wait; |
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341 | |
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342 | =head1 GLOBAL VARIABLES AND FUNCTIONS |
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343 | |
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344 | =over 4 |
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345 | |
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346 | =item $AnyEvent::MODEL |
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347 | |
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348 | Contains C<undef> until the first watcher is being created. Then it |
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349 | contains the event model that is being used, which is the name of the |
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350 | Perl class implementing the model. This class is usually one of the |
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351 | C<AnyEvent::Impl:xxx> modules, but can be any other class in the case |
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352 | AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>). |
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353 | |
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354 | The known classes so far are: |
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355 | |
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356 | AnyEvent::Impl::CoroEV based on Coro::EV, best choice. |
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357 | AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice. |
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358 | AnyEvent::Impl::EV based on EV (an interface to libev, best choice). |
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359 | AnyEvent::Impl::Event based on Event, second best choice. |
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360 | AnyEvent::Impl::Glib based on Glib, third-best choice. |
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361 | AnyEvent::Impl::Tk based on Tk, very bad choice. |
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362 | AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable. |
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363 | AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs). |
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364 | AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse. |
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365 | |
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366 | =item AnyEvent::detect |
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367 | |
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368 | Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model |
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369 | if necessary. You should only call this function right before you would |
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370 | have created an AnyEvent watcher anyway, that is, as late as possible at |
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371 | runtime. |
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372 | |
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373 | =back |
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374 | |
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375 | =head1 WHAT TO DO IN A MODULE |
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376 | |
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377 | As a module author, you should C<use AnyEvent> and call AnyEvent methods |
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378 | freely, but you should not load a specific event module or rely on it. |
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379 | |
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380 | Be careful when you create watchers in the module body - AnyEvent will |
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381 | decide which event module to use as soon as the first method is called, so |
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382 | by calling AnyEvent in your module body you force the user of your module |
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383 | to load the event module first. |
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384 | |
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385 | Never call C<< ->wait >> on a condition variable unless you I<know> that |
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386 | the C<< ->broadcast >> method has been called on it already. This is |
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387 | because it will stall the whole program, and the whole point of using |
|
|
388 | events is to stay interactive. |
|
|
389 | |
|
|
390 | It is fine, however, to call C<< ->wait >> when the user of your module |
|
|
391 | requests it (i.e. if you create a http request object ad have a method |
|
|
392 | called C<results> that returns the results, it should call C<< ->wait >> |
|
|
393 | freely, as the user of your module knows what she is doing. always). |
|
|
394 | |
|
|
395 | =head1 WHAT TO DO IN THE MAIN PROGRAM |
|
|
396 | |
|
|
397 | There will always be a single main program - the only place that should |
|
|
398 | dictate which event model to use. |
|
|
399 | |
|
|
400 | If it doesn't care, it can just "use AnyEvent" and use it itself, or not |
|
|
401 | do anything special (it does not need to be event-based) and let AnyEvent |
|
|
402 | decide which implementation to chose if some module relies on it. |
|
|
403 | |
|
|
404 | If the main program relies on a specific event model. For example, in |
|
|
405 | Gtk2 programs you have to rely on the Glib module. You should load the |
|
|
406 | event module before loading AnyEvent or any module that uses it: generally |
|
|
407 | speaking, you should load it as early as possible. The reason is that |
|
|
408 | modules might create watchers when they are loaded, and AnyEvent will |
|
|
409 | decide on the event model to use as soon as it creates watchers, and it |
|
|
410 | might chose the wrong one unless you load the correct one yourself. |
|
|
411 | |
|
|
412 | You can chose to use a rather inefficient pure-perl implementation by |
|
|
413 | loading the C<AnyEvent::Impl::Perl> module, which gives you similar |
|
|
414 | behaviour everywhere, but letting AnyEvent chose is generally better. |
|
|
415 | |
49 | =cut |
416 | =cut |
50 | |
417 | |
51 | package AnyEvent; |
418 | package AnyEvent; |
52 | |
419 | |
53 | no warnings; |
420 | no warnings; |
54 | use strict 'vars'; |
421 | use strict; |
|
|
422 | |
55 | use Carp; |
423 | use Carp; |
56 | |
424 | |
57 | our $VERSION = 0.1; |
425 | our $VERSION = '3.12'; |
58 | our $MODEL; |
426 | our $MODEL; |
59 | |
427 | |
60 | our $AUTOLOAD; |
428 | our $AUTOLOAD; |
61 | our @ISA; |
429 | our @ISA; |
62 | |
430 | |
|
|
431 | our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; |
|
|
432 | |
|
|
433 | our @REGISTRY; |
|
|
434 | |
63 | my @models = ( |
435 | my @models = ( |
64 | [Coro => Coro::Event::], |
436 | [Coro::EV:: => AnyEvent::Impl::CoroEV::], |
65 | [Event => Event::], |
437 | [Coro::Event:: => AnyEvent::Impl::CoroEvent::], |
66 | [Glib => Glib::], |
438 | [EV:: => AnyEvent::Impl::EV::], |
67 | [Tk => Tk::], |
439 | [Event:: => AnyEvent::Impl::Event::], |
|
|
440 | [Glib:: => AnyEvent::Impl::Glib::], |
|
|
441 | [Tk:: => AnyEvent::Impl::Tk::], |
|
|
442 | [AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::], |
68 | ); |
443 | ); |
|
|
444 | my @models_detect = ( |
|
|
445 | [Qt:: => AnyEvent::Impl::Qt::], # requires special main program |
|
|
446 | [Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy |
|
|
447 | ); |
69 | |
448 | |
70 | sub AUTOLOAD { |
449 | our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY); |
71 | $AUTOLOAD =~ s/.*://; |
|
|
72 | |
450 | |
|
|
451 | sub detect() { |
73 | unless ($MODEL) { |
452 | unless ($MODEL) { |
74 | # check for already loaded models |
453 | no strict 'refs'; |
75 | for (@models) { |
|
|
76 | my ($model, $package) = @$_; |
|
|
77 | if (scalar keys %{ *{"$package\::"} }) { |
|
|
78 | eval "require AnyEvent::Impl::$model" |
|
|
79 | or die; |
|
|
80 | |
454 | |
81 | last if $MODEL; |
455 | if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) { |
|
|
456 | my $model = "AnyEvent::Impl::$1"; |
|
|
457 | if (eval "require $model") { |
|
|
458 | $MODEL = $model; |
|
|
459 | warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1; |
82 | } |
460 | } |
83 | } |
461 | } |
84 | |
462 | |
|
|
463 | # check for already loaded models |
85 | unless ($MODEL) { |
464 | unless ($MODEL) { |
86 | # try to load a model |
465 | for (@REGISTRY, @models, @models_detect) { |
87 | |
|
|
88 | for (@models) { |
|
|
89 | my ($model, $package) = @$_; |
466 | my ($package, $model) = @$_; |
90 | eval "require AnyEvent::Impl::$model" |
467 | if (${"$package\::VERSION"} > 0) { |
|
|
468 | if (eval "require $model") { |
|
|
469 | $MODEL = $model; |
|
|
470 | warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1; |
|
|
471 | last; |
91 | or die; |
472 | } |
92 | |
473 | } |
93 | last if $MODEL; |
|
|
94 | } |
474 | } |
95 | |
475 | |
|
|
476 | unless ($MODEL) { |
|
|
477 | # try to load a model |
|
|
478 | |
|
|
479 | for (@REGISTRY, @models) { |
|
|
480 | my ($package, $model) = @$_; |
|
|
481 | if (eval "require $package" |
|
|
482 | and ${"$package\::VERSION"} > 0 |
|
|
483 | and eval "require $model") { |
|
|
484 | $MODEL = $model; |
|
|
485 | warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1; |
|
|
486 | last; |
|
|
487 | } |
|
|
488 | } |
|
|
489 | |
96 | $MODEL |
490 | $MODEL |
97 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk."; |
491 | 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."; |
|
|
492 | } |
98 | } |
493 | } |
|
|
494 | |
|
|
495 | unshift @ISA, $MODEL; |
|
|
496 | push @{"$MODEL\::ISA"}, "AnyEvent::Base"; |
99 | } |
497 | } |
100 | |
498 | |
101 | @ISA = $MODEL; |
499 | $MODEL |
|
|
500 | } |
|
|
501 | |
|
|
502 | sub AUTOLOAD { |
|
|
503 | (my $func = $AUTOLOAD) =~ s/.*://; |
|
|
504 | |
|
|
505 | $method{$func} |
|
|
506 | or croak "$func: not a valid method for AnyEvent objects"; |
|
|
507 | |
|
|
508 | detect unless $MODEL; |
102 | |
509 | |
103 | my $class = shift; |
510 | my $class = shift; |
104 | $class->$AUTOLOAD (@_); |
511 | $class->$func (@_); |
105 | } |
512 | } |
|
|
513 | |
|
|
514 | package AnyEvent::Base; |
|
|
515 | |
|
|
516 | # default implementation for ->condvar, ->wait, ->broadcast |
|
|
517 | |
|
|
518 | sub condvar { |
|
|
519 | bless \my $flag, "AnyEvent::Base::CondVar" |
|
|
520 | } |
|
|
521 | |
|
|
522 | sub AnyEvent::Base::CondVar::broadcast { |
|
|
523 | ${$_[0]}++; |
|
|
524 | } |
|
|
525 | |
|
|
526 | sub AnyEvent::Base::CondVar::wait { |
|
|
527 | AnyEvent->one_event while !${$_[0]}; |
|
|
528 | } |
|
|
529 | |
|
|
530 | # default implementation for ->signal |
|
|
531 | |
|
|
532 | our %SIG_CB; |
|
|
533 | |
|
|
534 | sub signal { |
|
|
535 | my (undef, %arg) = @_; |
|
|
536 | |
|
|
537 | my $signal = uc $arg{signal} |
|
|
538 | or Carp::croak "required option 'signal' is missing"; |
|
|
539 | |
|
|
540 | $SIG_CB{$signal}{$arg{cb}} = $arg{cb}; |
|
|
541 | $SIG{$signal} ||= sub { |
|
|
542 | $_->() for values %{ $SIG_CB{$signal} || {} }; |
|
|
543 | }; |
|
|
544 | |
|
|
545 | bless [$signal, $arg{cb}], "AnyEvent::Base::Signal" |
|
|
546 | } |
|
|
547 | |
|
|
548 | sub AnyEvent::Base::Signal::DESTROY { |
|
|
549 | my ($signal, $cb) = @{$_[0]}; |
|
|
550 | |
|
|
551 | delete $SIG_CB{$signal}{$cb}; |
|
|
552 | |
|
|
553 | $SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} }; |
|
|
554 | } |
|
|
555 | |
|
|
556 | # default implementation for ->child |
|
|
557 | |
|
|
558 | our %PID_CB; |
|
|
559 | our $CHLD_W; |
|
|
560 | our $CHLD_DELAY_W; |
|
|
561 | our $PID_IDLE; |
|
|
562 | our $WNOHANG; |
|
|
563 | |
|
|
564 | sub _child_wait { |
|
|
565 | while (0 < (my $pid = waitpid -1, $WNOHANG)) { |
|
|
566 | $_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }), |
|
|
567 | (values %{ $PID_CB{0} || {} }); |
|
|
568 | } |
|
|
569 | |
|
|
570 | undef $PID_IDLE; |
|
|
571 | } |
|
|
572 | |
|
|
573 | sub _sigchld { |
|
|
574 | # make sure we deliver these changes "synchronous" with the event loop. |
|
|
575 | $CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub { |
|
|
576 | undef $CHLD_DELAY_W; |
|
|
577 | &_child_wait; |
|
|
578 | }); |
|
|
579 | } |
|
|
580 | |
|
|
581 | sub child { |
|
|
582 | my (undef, %arg) = @_; |
|
|
583 | |
|
|
584 | defined (my $pid = $arg{pid} + 0) |
|
|
585 | or Carp::croak "required option 'pid' is missing"; |
|
|
586 | |
|
|
587 | $PID_CB{$pid}{$arg{cb}} = $arg{cb}; |
|
|
588 | |
|
|
589 | unless ($WNOHANG) { |
|
|
590 | $WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1; |
|
|
591 | } |
|
|
592 | |
|
|
593 | unless ($CHLD_W) { |
|
|
594 | $CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld); |
|
|
595 | # child could be a zombie already, so make at least one round |
|
|
596 | &_sigchld; |
|
|
597 | } |
|
|
598 | |
|
|
599 | bless [$pid, $arg{cb}], "AnyEvent::Base::Child" |
|
|
600 | } |
|
|
601 | |
|
|
602 | sub AnyEvent::Base::Child::DESTROY { |
|
|
603 | my ($pid, $cb) = @{$_[0]}; |
|
|
604 | |
|
|
605 | delete $PID_CB{$pid}{$cb}; |
|
|
606 | delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} }; |
|
|
607 | |
|
|
608 | undef $CHLD_W unless keys %PID_CB; |
|
|
609 | } |
|
|
610 | |
|
|
611 | =head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE |
|
|
612 | |
|
|
613 | This is an advanced topic that you do not normally need to use AnyEvent in |
|
|
614 | a module. This section is only of use to event loop authors who want to |
|
|
615 | provide AnyEvent compatibility. |
|
|
616 | |
|
|
617 | If you need to support another event library which isn't directly |
|
|
618 | supported by AnyEvent, you can supply your own interface to it by |
|
|
619 | pushing, before the first watcher gets created, the package name of |
|
|
620 | the event module and the package name of the interface to use onto |
|
|
621 | C<@AnyEvent::REGISTRY>. You can do that before and even without loading |
|
|
622 | AnyEvent, so it is reasonably cheap. |
|
|
623 | |
|
|
624 | Example: |
|
|
625 | |
|
|
626 | push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::]; |
|
|
627 | |
|
|
628 | This tells AnyEvent to (literally) use the C<urxvt::anyevent::> |
|
|
629 | package/class when it finds the C<urxvt> package/module is already loaded. |
|
|
630 | |
|
|
631 | When AnyEvent is loaded and asked to find a suitable event model, it |
|
|
632 | will first check for the presence of urxvt by trying to C<use> the |
|
|
633 | C<urxvt::anyevent> module. |
|
|
634 | |
|
|
635 | The class should provide implementations for all watcher types. See |
|
|
636 | L<AnyEvent::Impl::EV> (source code), L<AnyEvent::Impl::Glib> (Source code) |
|
|
637 | and so on for actual examples. Use C<perldoc -m AnyEvent::Impl::Glib> to |
|
|
638 | see the sources. |
|
|
639 | |
|
|
640 | If you don't provide C<signal> and C<child> watchers than AnyEvent will |
|
|
641 | provide suitable (hopefully) replacements. |
|
|
642 | |
|
|
643 | The above example isn't fictitious, the I<rxvt-unicode> (a.k.a. urxvt) |
|
|
644 | terminal emulator uses the above line as-is. An interface isn't included |
|
|
645 | in AnyEvent because it doesn't make sense outside the embedded interpreter |
|
|
646 | inside I<rxvt-unicode>, and it is updated and maintained as part of the |
|
|
647 | I<rxvt-unicode> distribution. |
|
|
648 | |
|
|
649 | I<rxvt-unicode> also cheats a bit by not providing blocking access to |
|
|
650 | condition variables: code blocking while waiting for a condition will |
|
|
651 | C<die>. This still works with most modules/usages, and blocking calls must |
|
|
652 | not be done in an interactive application, so it makes sense. |
|
|
653 | |
|
|
654 | =head1 ENVIRONMENT VARIABLES |
|
|
655 | |
|
|
656 | The following environment variables are used by this module: |
|
|
657 | |
|
|
658 | =over 4 |
|
|
659 | |
|
|
660 | =item C<PERL_ANYEVENT_VERBOSE> |
|
|
661 | |
|
|
662 | When set to C<2> or higher, cause AnyEvent to report to STDERR which event |
|
|
663 | model it chooses. |
|
|
664 | |
|
|
665 | =item C<PERL_ANYEVENT_MODEL> |
|
|
666 | |
|
|
667 | This can be used to specify the event model to be used by AnyEvent, before |
|
|
668 | autodetection and -probing kicks in. It must be a string consisting |
|
|
669 | entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended |
|
|
670 | and the resulting module name is loaded and if the load was successful, |
|
|
671 | used as event model. If it fails to load AnyEvent will proceed with |
|
|
672 | autodetection and -probing. |
|
|
673 | |
|
|
674 | This functionality might change in future versions. |
|
|
675 | |
|
|
676 | For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you |
|
|
677 | could start your program like this: |
|
|
678 | |
|
|
679 | PERL_ANYEVENT_MODEL=Perl perl ... |
106 | |
680 | |
107 | =back |
681 | =back |
108 | |
682 | |
109 | =head1 EXAMPLE |
683 | =head1 EXAMPLE PROGRAM |
110 | |
684 | |
111 | The following program uses an io watcher to read data from stdin, a timer |
685 | The following program uses an IO watcher to read data from STDIN, a timer |
112 | to display a message once per second, and a condvar to exit the program |
686 | to display a message once per second, and a condition variable to quit the |
113 | when the user enters quit: |
687 | program when the user enters quit: |
114 | |
688 | |
115 | use AnyEvent; |
689 | use AnyEvent; |
116 | |
690 | |
117 | my $cv = AnyEvent->condvar; |
691 | my $cv = AnyEvent->condvar; |
118 | |
692 | |
119 | my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
693 | my $io_watcher = AnyEvent->io ( |
|
|
694 | fh => \*STDIN, |
|
|
695 | poll => 'r', |
|
|
696 | cb => sub { |
120 | warn "io event <$_[0]>\n"; # will always output <r> |
697 | warn "io event <$_[0]>\n"; # will always output <r> |
121 | chomp (my $input = <STDIN>); # read a line |
698 | chomp (my $input = <STDIN>); # read a line |
122 | warn "read: $input\n"; # output what has been read |
699 | warn "read: $input\n"; # output what has been read |
123 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
700 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
|
|
701 | }, |
124 | }); |
702 | ); |
125 | |
703 | |
126 | my $time_watcher; # can only be used once |
704 | my $time_watcher; # can only be used once |
127 | |
705 | |
128 | sub new_timer { |
706 | sub new_timer { |
129 | $timer = AnyEvent->timer (after => 1, cb => sub { |
707 | $timer = AnyEvent->timer (after => 1, cb => sub { |
… | |
… | |
134 | |
712 | |
135 | new_timer; # create first timer |
713 | new_timer; # create first timer |
136 | |
714 | |
137 | $cv->wait; # wait until user enters /^q/i |
715 | $cv->wait; # wait until user enters /^q/i |
138 | |
716 | |
|
|
717 | =head1 REAL-WORLD EXAMPLE |
|
|
718 | |
|
|
719 | Consider the L<Net::FCP> module. It features (among others) the following |
|
|
720 | API calls, which are to freenet what HTTP GET requests are to http: |
|
|
721 | |
|
|
722 | my $data = $fcp->client_get ($url); # blocks |
|
|
723 | |
|
|
724 | my $transaction = $fcp->txn_client_get ($url); # does not block |
|
|
725 | $transaction->cb ( sub { ... } ); # set optional result callback |
|
|
726 | my $data = $transaction->result; # possibly blocks |
|
|
727 | |
|
|
728 | The C<client_get> method works like C<LWP::Simple::get>: it requests the |
|
|
729 | given URL and waits till the data has arrived. It is defined to be: |
|
|
730 | |
|
|
731 | sub client_get { $_[0]->txn_client_get ($_[1])->result } |
|
|
732 | |
|
|
733 | And in fact is automatically generated. This is the blocking API of |
|
|
734 | L<Net::FCP>, and it works as simple as in any other, similar, module. |
|
|
735 | |
|
|
736 | More complicated is C<txn_client_get>: It only creates a transaction |
|
|
737 | (completion, result, ...) object and initiates the transaction. |
|
|
738 | |
|
|
739 | my $txn = bless { }, Net::FCP::Txn::; |
|
|
740 | |
|
|
741 | It also creates a condition variable that is used to signal the completion |
|
|
742 | of the request: |
|
|
743 | |
|
|
744 | $txn->{finished} = AnyAvent->condvar; |
|
|
745 | |
|
|
746 | It then creates a socket in non-blocking mode. |
|
|
747 | |
|
|
748 | socket $txn->{fh}, ...; |
|
|
749 | fcntl $txn->{fh}, F_SETFL, O_NONBLOCK; |
|
|
750 | connect $txn->{fh}, ... |
|
|
751 | and !$!{EWOULDBLOCK} |
|
|
752 | and !$!{EINPROGRESS} |
|
|
753 | and Carp::croak "unable to connect: $!\n"; |
|
|
754 | |
|
|
755 | Then it creates a write-watcher which gets called whenever an error occurs |
|
|
756 | or the connection succeeds: |
|
|
757 | |
|
|
758 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'w', cb => sub { $txn->fh_ready_w }); |
|
|
759 | |
|
|
760 | And returns this transaction object. The C<fh_ready_w> callback gets |
|
|
761 | called as soon as the event loop detects that the socket is ready for |
|
|
762 | writing. |
|
|
763 | |
|
|
764 | The C<fh_ready_w> method makes the socket blocking again, writes the |
|
|
765 | request data and replaces the watcher by a read watcher (waiting for reply |
|
|
766 | data). The actual code is more complicated, but that doesn't matter for |
|
|
767 | this example: |
|
|
768 | |
|
|
769 | fcntl $txn->{fh}, F_SETFL, 0; |
|
|
770 | syswrite $txn->{fh}, $txn->{request} |
|
|
771 | or die "connection or write error"; |
|
|
772 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
|
|
773 | |
|
|
774 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
|
|
775 | result and signals any possible waiters that the request ahs finished: |
|
|
776 | |
|
|
777 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
|
|
778 | |
|
|
779 | if (end-of-file or data complete) { |
|
|
780 | $txn->{result} = $txn->{buf}; |
|
|
781 | $txn->{finished}->broadcast; |
|
|
782 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
|
|
783 | } |
|
|
784 | |
|
|
785 | The C<result> method, finally, just waits for the finished signal (if the |
|
|
786 | request was already finished, it doesn't wait, of course, and returns the |
|
|
787 | data: |
|
|
788 | |
|
|
789 | $txn->{finished}->wait; |
|
|
790 | return $txn->{result}; |
|
|
791 | |
|
|
792 | The actual code goes further and collects all errors (C<die>s, exceptions) |
|
|
793 | that occured during request processing. The C<result> method detects |
|
|
794 | whether an exception as thrown (it is stored inside the $txn object) |
|
|
795 | and just throws the exception, which means connection errors and other |
|
|
796 | problems get reported tot he code that tries to use the result, not in a |
|
|
797 | random callback. |
|
|
798 | |
|
|
799 | All of this enables the following usage styles: |
|
|
800 | |
|
|
801 | 1. Blocking: |
|
|
802 | |
|
|
803 | my $data = $fcp->client_get ($url); |
|
|
804 | |
|
|
805 | 2. Blocking, but running in parallel: |
|
|
806 | |
|
|
807 | my @datas = map $_->result, |
|
|
808 | map $fcp->txn_client_get ($_), |
|
|
809 | @urls; |
|
|
810 | |
|
|
811 | Both blocking examples work without the module user having to know |
|
|
812 | anything about events. |
|
|
813 | |
|
|
814 | 3a. Event-based in a main program, using any supported event module: |
|
|
815 | |
|
|
816 | use EV; |
|
|
817 | |
|
|
818 | $fcp->txn_client_get ($url)->cb (sub { |
|
|
819 | my $txn = shift; |
|
|
820 | my $data = $txn->result; |
|
|
821 | ... |
|
|
822 | }); |
|
|
823 | |
|
|
824 | EV::loop; |
|
|
825 | |
|
|
826 | 3b. The module user could use AnyEvent, too: |
|
|
827 | |
|
|
828 | use AnyEvent; |
|
|
829 | |
|
|
830 | my $quit = AnyEvent->condvar; |
|
|
831 | |
|
|
832 | $fcp->txn_client_get ($url)->cb (sub { |
|
|
833 | ... |
|
|
834 | $quit->broadcast; |
|
|
835 | }); |
|
|
836 | |
|
|
837 | $quit->wait; |
|
|
838 | |
|
|
839 | =head1 FORK |
|
|
840 | |
|
|
841 | Most event libraries are not fork-safe. The ones who are usually are |
|
|
842 | because they are so inefficient. Only L<EV> is fully fork-aware. |
|
|
843 | |
|
|
844 | If you have to fork, you must either do so I<before> creating your first |
|
|
845 | watcher OR you must not use AnyEvent at all in the child. |
|
|
846 | |
|
|
847 | =head1 SECURITY CONSIDERATIONS |
|
|
848 | |
|
|
849 | AnyEvent can be forced to load any event model via |
|
|
850 | $ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to |
|
|
851 | execute arbitrary code or directly gain access, it can easily be used to |
|
|
852 | make the program hang or malfunction in subtle ways, as AnyEvent watchers |
|
|
853 | will not be active when the program uses a different event model than |
|
|
854 | specified in the variable. |
|
|
855 | |
|
|
856 | You can make AnyEvent completely ignore this variable by deleting it |
|
|
857 | before the first watcher gets created, e.g. with a C<BEGIN> block: |
|
|
858 | |
|
|
859 | BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} } |
|
|
860 | |
|
|
861 | use AnyEvent; |
|
|
862 | |
139 | =head1 SEE ALSO |
863 | =head1 SEE ALSO |
140 | |
864 | |
|
|
865 | Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>, |
141 | L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>, |
866 | L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>, |
142 | L<AnyEvent::Impl::Coro>, |
867 | L<Event::Lib>, L<Qt>. |
143 | L<AnyEvent::Impl::Event>, |
868 | |
144 | L<AnyEvent::Impl::Glib>, |
869 | Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>, |
|
|
870 | L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, |
|
|
871 | L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>, |
145 | L<AnyEvent::Impl::Tk>. |
872 | L<AnyEvent::Impl::Qt>. |
146 | |
873 | |
147 | =head1 |
874 | Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. |
|
|
875 | |
|
|
876 | =head1 AUTHOR |
|
|
877 | |
|
|
878 | Marc Lehmann <schmorp@schmorp.de> |
|
|
879 | http://home.schmorp.de/ |
148 | |
880 | |
149 | =cut |
881 | =cut |
150 | |
882 | |
151 | 1 |
883 | 1 |
152 | |
884 | |