| 1 | =head1 NAME |
1 | =head1 NAME |
| 2 | |
2 | |
| 3 | AnyEvent - ??? |
3 | AnyEvent - provide framework for multiple event loops |
|
|
4 | |
|
|
5 | Event, Coro, Glib, Tk - various supported event loops |
| 4 | |
6 | |
| 5 | =head1 SYNOPSIS |
7 | =head1 SYNOPSIS |
| 6 | |
8 | |
|
|
9 | use AnyEvent; |
|
|
10 | |
|
|
11 | my $w = AnyEvent->io (fh => ..., poll => "[rw]+", cb => sub { |
|
|
12 | my ($poll_got) = @_; |
|
|
13 | ... |
|
|
14 | }); |
|
|
15 | |
|
|
16 | - only one io watcher per $fh and $poll type is allowed |
|
|
17 | (i.e. on a socket you can have one r + one w or one rw |
|
|
18 | watcher, not any more. |
|
|
19 | |
|
|
20 | - AnyEvent will keep filehandles alive, so as long as the watcher exists, |
|
|
21 | the filehandle exists. |
|
|
22 | |
|
|
23 | my $w = AnyEvent->timer (after => $seconds, cb => sub { |
|
|
24 | ... |
|
|
25 | }); |
|
|
26 | |
|
|
27 | - io and time watchers get canceled whenever $w is destroyed, so keep a copy |
|
|
28 | |
|
|
29 | - timers can only be used once and must be recreated for repeated operation |
|
|
30 | |
|
|
31 | my $w = AnyEvent->condvar; # kind of main loop replacement |
|
|
32 | $w->wait; # enters main loop till $condvar gets ->broadcast |
|
|
33 | $w->broadcast; # wake up current and all future wait's |
|
|
34 | |
|
|
35 | - condvars are used to give blocking behaviour when neccessary. Create |
|
|
36 | a condvar for any "request" or "event" your module might create, C<< |
|
|
37 | ->broadcast >> it when the event happens and provide a function that calls |
|
|
38 | C<< ->wait >> for it. See the examples below. |
|
|
39 | |
| 7 | =head1 DESCRIPTION |
40 | =head1 DESCRIPTION |
| 8 | |
41 | |
|
|
42 | L<AnyEvent> provides an identical interface to multiple event loops. This |
|
|
43 | allows module authors to utilizy an event loop without forcing module |
|
|
44 | users to use the same event loop (as only a single event loop can coexist |
|
|
45 | peacefully at any one time). |
|
|
46 | |
|
|
47 | The interface itself is vaguely similar but not identical to the Event |
|
|
48 | module. |
|
|
49 | |
|
|
50 | On the first call of any method, the module tries to detect the currently |
|
|
51 | loaded event loop by probing wether any of the following modules is |
|
|
52 | loaded: L<Coro::Event>, L<Event>, L<Glib>, L<Tk>. The first one found is |
|
|
53 | used. If none is found, the module tries to load these modules in the |
|
|
54 | order given. The first one that could be successfully loaded will be |
|
|
55 | used. If still none could be found, it will issue an error. |
|
|
56 | |
| 9 | =over 4 |
57 | =over 4 |
| 10 | |
58 | |
| 11 | =cut |
59 | =cut |
| 12 | |
60 | |
| 13 | package AnyEvent; |
61 | package AnyEvent; |
| 14 | |
62 | |
|
|
63 | no warnings; |
|
|
64 | use strict 'vars'; |
| 15 | use Carp; |
65 | use Carp; |
| 16 | |
66 | |
| 17 | $VERSION = 0.1; |
67 | our $VERSION = 0.3; |
|
|
68 | our $MODEL; |
| 18 | |
69 | |
| 19 | no warnings; |
70 | our $AUTOLOAD; |
|
|
71 | our @ISA; |
| 20 | |
72 | |
| 21 | my @models = ( |
73 | my @models = ( |
| 22 | [Coro => Coro::Event::], |
74 | [Coro => Coro::Event::], |
| 23 | [Event => Event::], |
75 | [Event => Event::], |
| 24 | [Glib => Glib::], |
76 | [Glib => Glib::], |
| 25 | [Tk => Tk::], |
77 | [Tk => Tk::], |
| 26 | ); |
78 | ); |
| 27 | |
79 | |
|
|
80 | our %method = map +($_ => 1), qw(io timer condvar broadcast wait cancel DESTROY); |
|
|
81 | |
| 28 | sub AUTOLOAD { |
82 | sub AUTOLOAD { |
| 29 | $AUTOLOAD =~ s/.*://; |
83 | $AUTOLOAD =~ s/.*://; |
| 30 | |
84 | |
|
|
85 | $method{$AUTOLOAD} |
|
|
86 | or croak "$AUTOLOAD: not a valid method for AnyEvent objects"; |
|
|
87 | |
|
|
88 | unless ($MODEL) { |
|
|
89 | # check for already loaded models |
| 31 | for (@models) { |
90 | for (@models) { |
| 32 | my ($model, $package) = @$_; |
91 | my ($model, $package) = @$_; |
| 33 | if (defined ${"$package\::VERSION"}) { |
92 | if (scalar keys %{ *{"$package\::"} }) { |
| 34 | $EVENT = "AnyEvent::Impl::$model"; |
93 | eval "require AnyEvent::Impl::$model"; |
| 35 | eval "require $EVENT"; die if $@; |
94 | last if $MODEL; |
| 36 | goto &{"$EVENT\::$AUTOLOAD"}; |
95 | } |
|
|
96 | } |
|
|
97 | |
|
|
98 | unless ($MODEL) { |
|
|
99 | # try to load a model |
|
|
100 | |
|
|
101 | for (@models) { |
|
|
102 | my ($model, $package) = @$_; |
|
|
103 | eval "require AnyEvent::Impl::$model"; |
|
|
104 | last if $MODEL; |
|
|
105 | } |
|
|
106 | |
|
|
107 | $MODEL |
|
|
108 | or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: Coro, Event, Glib or Tk."; |
| 37 | } |
109 | } |
| 38 | } |
110 | } |
| 39 | |
111 | |
| 40 | for (@models) { |
112 | @ISA = $MODEL; |
| 41 | my ($model, $package) = @$_; |
113 | |
| 42 | $EVENT = "AnyEvent::Impl::$model"; |
114 | my $class = shift; |
| 43 | if (eval "require $EVENT") { |
115 | $class->$AUTOLOAD (@_); |
| 44 | goto &{"$EVENT\::$AUTOLOAD"}; |
116 | } |
|
|
117 | |
|
|
118 | =back |
|
|
119 | |
|
|
120 | =head1 EXAMPLE |
|
|
121 | |
|
|
122 | The following program uses an io watcher to read data from stdin, a timer |
|
|
123 | to display a message once per second, and a condvar to exit the program |
|
|
124 | when the user enters quit: |
|
|
125 | |
|
|
126 | use AnyEvent; |
|
|
127 | |
|
|
128 | my $cv = AnyEvent->condvar; |
|
|
129 | |
|
|
130 | my $io_watcher = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub { |
|
|
131 | warn "io event <$_[0]>\n"; # will always output <r> |
|
|
132 | chomp (my $input = <STDIN>); # read a line |
|
|
133 | warn "read: $input\n"; # output what has been read |
|
|
134 | $cv->broadcast if $input =~ /^q/i; # quit program if /^q/i |
|
|
135 | }); |
|
|
136 | |
|
|
137 | my $time_watcher; # can only be used once |
|
|
138 | |
|
|
139 | sub new_timer { |
|
|
140 | $timer = AnyEvent->timer (after => 1, cb => sub { |
|
|
141 | warn "timeout\n"; # print 'timeout' about every second |
|
|
142 | &new_timer; # and restart the time |
| 45 | } |
143 | }); |
| 46 | } |
144 | } |
| 47 | |
145 | |
| 48 | die "No event module selected for AnyEvent and autodetect failed. Install any of these: Coro, Event, Glib or Tk."; |
146 | new_timer; # create first timer |
| 49 | } |
|
|
| 50 | |
147 | |
| 51 | 1; |
148 | $cv->wait; # wait until user enters /^q/i |
| 52 | |
149 | |
|
|
150 | =head1 REAL-WORLD EXAMPLE |
|
|
151 | |
|
|
152 | Consider the L<Net::FCP> module. It features (among others) the following |
|
|
153 | API calls, which are to freenet what HTTP GET requests are to http: |
|
|
154 | |
|
|
155 | my $data = $fcp->client_get ($url); # blocks |
|
|
156 | |
|
|
157 | my $transaction = $fcp->txn_client_get ($url); # does not block |
|
|
158 | $transaction->cb ( sub { ... } ); # set optional result callback |
|
|
159 | my $data = $transaction->result; # possibly blocks |
|
|
160 | |
|
|
161 | The C<client_get> method works like C<LWP::Simple::get>: it requests the |
|
|
162 | given URL and waits till the data has arrived. It is defined to be: |
|
|
163 | |
|
|
164 | sub client_get { $_[0]->txn_client_get ($_[1])->result } |
|
|
165 | |
|
|
166 | And in fact is automatically generated. This is the blocking API of |
|
|
167 | L<Net::FCP>, and it works as simple as in any other, similar, module. |
|
|
168 | |
|
|
169 | More complicated is C<txn_client_get>: It only creates a transaction |
|
|
170 | (completion, result, ...) object and initiates the transaction. |
|
|
171 | |
|
|
172 | my $txn = bless { }, Net::FCP::Txn::; |
|
|
173 | |
|
|
174 | It also creates a condition variable that is used to signal the completion |
|
|
175 | of the request: |
|
|
176 | |
|
|
177 | $txn->{finished} = AnyAvent->condvar; |
|
|
178 | |
|
|
179 | It then creates a socket in non-blocking mode. |
|
|
180 | |
|
|
181 | socket $txn->{fh}, ...; |
|
|
182 | fcntl $txn->{fh}, F_SETFL, O_NONBLOCK; |
|
|
183 | connect $txn->{fh}, ... |
|
|
184 | and !$!{EWOULDBLOCK} |
|
|
185 | and !$!{EINPROGRESS} |
|
|
186 | and Carp::croak "unable to connect: $!\n"; |
|
|
187 | |
|
|
188 | Then it creates a write-watcher which gets called whenever an error occurs |
|
|
189 | or the connection succeeds: |
|
|
190 | |
|
|
191 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'w', cb => sub { $txn->fh_ready_w }); |
|
|
192 | |
|
|
193 | And returns this transaction object. The C<fh_ready_w> callback gets |
|
|
194 | called as soon as the event loop detects that the socket is ready for |
|
|
195 | writing. |
|
|
196 | |
|
|
197 | The C<fh_ready_w> method makes the socket blocking again, writes the |
|
|
198 | request data and replaces the watcher by a read watcher (waiting for reply |
|
|
199 | data). The actual code is more complicated, but that doesn't matter for |
|
|
200 | this example: |
|
|
201 | |
|
|
202 | fcntl $txn->{fh}, F_SETFL, 0; |
|
|
203 | syswrite $txn->{fh}, $txn->{request} |
|
|
204 | or die "connection or write error"; |
|
|
205 | $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); |
|
|
206 | |
|
|
207 | Again, C<fh_ready_r> waits till all data has arrived, and then stores the |
|
|
208 | result and signals any possible waiters that the request ahs finished: |
|
|
209 | |
|
|
210 | sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; |
|
|
211 | |
|
|
212 | if (end-of-file or data complete) { |
|
|
213 | $txn->{result} = $txn->{buf}; |
|
|
214 | $txn->{finished}->broadcast; |
|
|
215 | $txb->{cb}->($txn) of $txn->{cb}; # also call callback |
|
|
216 | } |
|
|
217 | |
|
|
218 | The C<result> method, finally, just waits for the finished signal (if the |
|
|
219 | request was already finished, it doesn't wait, of course, and returns the |
|
|
220 | data: |
|
|
221 | |
|
|
222 | $txn->{finished}->wait; |
|
|
223 | return $txn->{result}; |
|
|
224 | |
|
|
225 | The actual code goes further and collects all errors (C<die>s, exceptions) |
|
|
226 | that occured during request processing. The C<result> method detects |
|
|
227 | wether an exception as thrown (it is stored inside the $txn object) |
|
|
228 | and just throws the exception, which means connection errors and other |
|
|
229 | problems get reported tot he code that tries to use the result, not in a |
|
|
230 | random callback. |
|
|
231 | |
|
|
232 | All of this enables the following usage styles: |
|
|
233 | |
|
|
234 | 1. Blocking: |
|
|
235 | |
|
|
236 | my $data = $fcp->client_get ($url); |
|
|
237 | |
|
|
238 | 2. Blocking, but parallelizing: |
|
|
239 | |
|
|
240 | my @datas = map $_->result, |
|
|
241 | map $fcp->txn_client_get ($_), |
|
|
242 | @urls; |
|
|
243 | |
|
|
244 | Both blocking examples work without the module user having to know |
|
|
245 | anything about events. |
|
|
246 | |
|
|
247 | 3a. Event-based in a main program, using any support Event module: |
|
|
248 | |
|
|
249 | use Event; |
|
|
250 | |
|
|
251 | $fcp->txn_client_get ($url)->cb (sub { |
|
|
252 | my $txn = shift; |
|
|
253 | my $data = $txn->result; |
|
|
254 | ... |
|
|
255 | }); |
|
|
256 | |
|
|
257 | Event::loop; |
|
|
258 | |
|
|
259 | 3b. The module user could use AnyEvent, too: |
|
|
260 | |
|
|
261 | use AnyEvent; |
|
|
262 | |
|
|
263 | my $quit = AnyEvent->condvar; |
|
|
264 | |
|
|
265 | $fcp->txn_client_get ($url)->cb (sub { |
|
|
266 | ... |
|
|
267 | $quit->broadcast; |
|
|
268 | }); |
|
|
269 | |
|
|
270 | $quit->wait; |
|
|
271 | |
|
|
272 | =head1 SEE ALSO |
|
|
273 | |
|
|
274 | Event modules: L<Coro::Event>, L<Coro>, L<Event>, L<Glib::Event>, L<Glib>. |
|
|
275 | |
|
|
276 | Implementations: L<AnyEvent::Impl::Coro>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>. |
|
|
277 | |
|
|
278 | Nontrivial usage example: L<Net::FCP>. |
|
|
279 | |
|
|
280 | =head1 |
|
|
281 | |
|
|
282 | =cut |
|
|
283 | |
|
|
284 | 1 |
|
|
285 | |
