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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.119 by root, Sat May 17 19:39:33 2008 UTC vs.
Revision 1.128 by root, Sat May 24 02:50:45 2008 UTC

1=head1 NAME 1=head1 => NAME
2 2
3AnyEvent - provide framework for multiple event loops 3AnyEvent - provide framework for multiple event loops
4 4
5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops 5EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6 6
57as those use one of the supported event loops. It is trivial to add new 57as those use one of the supported event loops. It is trivial to add new
58event loops to AnyEvent, too, so it is future-proof). 58event loops to AnyEvent, too, so it is future-proof).
59 59
60In addition to being free of having to use I<the one and only true event 60In addition to being free of having to use I<the one and only true event
61model>, AnyEvent also is free of bloat and policy: with POE or similar 61model>, AnyEvent also is free of bloat and policy: with POE or similar
62modules, you get an enourmous amount of code and strict rules you have to 62modules, you get an enormous amount of code and strict rules you have to
63follow. AnyEvent, on the other hand, is lean and up to the point, by only 63follow. AnyEvent, on the other hand, is lean and up to the point, by only
64offering the functionality that is necessary, in as thin as a wrapper as 64offering the functionality that is necessary, in as thin as a wrapper as
65technically possible. 65technically possible.
66 66
67Of course, if you want lots of policy (this can arguably be somewhat 67Of course, if you want lots of policy (this can arguably be somewhat
108 108
109=head1 WATCHERS 109=head1 WATCHERS
110 110
111AnyEvent has the central concept of a I<watcher>, which is an object that 111AnyEvent has the central concept of a I<watcher>, which is an object that
112stores relevant data for each kind of event you are waiting for, such as 112stores relevant data for each kind of event you are waiting for, such as
113the callback to call, the filehandle to watch, etc. 113the callback to call, the file handle to watch, etc.
114 114
115These watchers are normal Perl objects with normal Perl lifetime. After 115These watchers are normal Perl objects with normal Perl lifetime. After
116creating a watcher it will immediately "watch" for events and invoke the 116creating a watcher it will immediately "watch" for events and invoke the
117callback when the event occurs (of course, only when the event model 117callback when the event occurs (of course, only when the event model
118is in control). 118is in control).
631 631
632=item L<AnyEvent::Handle> 632=item L<AnyEvent::Handle>
633 633
634Provide read and write buffers and manages watchers for reads and writes. 634Provide read and write buffers and manages watchers for reads and writes.
635 635
636=item L<AnyEvent::Socket>
637
638Provides various utility functions for (internet protocol) sockets,
639addresses and name resolution. Also functions to create non-blocking tcp
640connections or tcp servers, with IPv6 and SRV record support and more.
641
636=item L<AnyEvent::HTTPD> 642=item L<AnyEvent::HTTPD>
637 643
638Provides a simple web application server framework. 644Provides a simple web application server framework.
639 645
640=item L<AnyEvent::DNS> 646=item L<AnyEvent::DNS>
641 647
642Provides asynchronous DNS resolver capabilities, beyond what 648Provides rich asynchronous DNS resolver capabilities.
643L<AnyEvent::Util> offers.
644 649
645=item L<AnyEvent::FastPing> 650=item L<AnyEvent::FastPing>
646 651
647The fastest ping in the west. 652The fastest ping in the west.
648 653
691no warnings; 696no warnings;
692use strict; 697use strict;
693 698
694use Carp; 699use Carp;
695 700
696our $VERSION = '3.41'; 701our $VERSION = '3.6';
697our $MODEL; 702our $MODEL;
698 703
699our $AUTOLOAD; 704our $AUTOLOAD;
700our @ISA; 705our @ISA;
701 706
702our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1; 707our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
703 708
704our @REGISTRY; 709our @REGISTRY;
710
711our %PROTOCOL; # (ipv4|ipv6) => (1|2)
712
713{
714 my $idx;
715 $PROTOCOL{$_} = ++$idx
716 for split /\s*,\s*/, $ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
717}
705 718
706my @models = ( 719my @models = (
707 [EV:: => AnyEvent::Impl::EV::], 720 [EV:: => AnyEvent::Impl::EV::],
708 [Event:: => AnyEvent::Impl::Event::], 721 [Event:: => AnyEvent::Impl::Event::],
709 [Tk:: => AnyEvent::Impl::Tk::], 722 [Tk:: => AnyEvent::Impl::Tk::],
811package AnyEvent::Base; 824package AnyEvent::Base;
812 825
813# default implementation for ->condvar 826# default implementation for ->condvar
814 827
815sub condvar { 828sub condvar {
816 bless {}, AnyEvent::CondVar:: 829 bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
817} 830}
818 831
819# default implementation for ->signal 832# default implementation for ->signal
820 833
821our %SIG_CB; 834our %SIG_CB;
944 $_[0]{_ae_end_cb} = $_[1] if @_ > 1; 957 $_[0]{_ae_end_cb} = $_[1] if @_ > 1;
945} 958}
946 959
947sub end { 960sub end {
948 return if --$_[0]{_ae_counter}; 961 return if --$_[0]{_ae_counter};
949 &{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb}; 962 &{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
950} 963}
951 964
952# undocumented/compatibility with pre-3.4 965# undocumented/compatibility with pre-3.4
953*broadcast = \&send; 966*broadcast = \&send;
954*wait = \&_wait; 967*wait = \&_wait;
1016model it chooses. 1029model it chooses.
1017 1030
1018=item C<PERL_ANYEVENT_MODEL> 1031=item C<PERL_ANYEVENT_MODEL>
1019 1032
1020This can be used to specify the event model to be used by AnyEvent, before 1033This can be used to specify the event model to be used by AnyEvent, before
1021autodetection and -probing kicks in. It must be a string consisting 1034auto detection and -probing kicks in. It must be a string consisting
1022entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended 1035entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1023and the resulting module name is loaded and if the load was successful, 1036and the resulting module name is loaded and if the load was successful,
1024used as event model. If it fails to load AnyEvent will proceed with 1037used as event model. If it fails to load AnyEvent will proceed with
1025autodetection and -probing. 1038auto detection and -probing.
1026 1039
1027This functionality might change in future versions. 1040This functionality might change in future versions.
1028 1041
1029For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you 1042For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1030could start your program like this: 1043could start your program like this:
1031 1044
1032 PERL_ANYEVENT_MODEL=Perl perl ... 1045 PERL_ANYEVENT_MODEL=Perl perl ...
1046
1047=item C<PERL_ANYEVENT_PROTOCOLS>
1048
1049Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1050for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1051of auto probing).
1052
1053Must be set to a comma-separated list of protocols or address families,
1054current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1055used, and preference will be given to protocols mentioned earlier in the
1056list.
1057
1058This variable can effectively be used for denial-of-service attacks
1059against local programs (e.g. when setuid), although the impact is likely
1060small, as the program has to handle connection errors already-
1061
1062Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1063but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1064- only support IPv4, never try to resolve or contact IPv6
1065addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1066IPv6, but prefer IPv6 over IPv4.
1067
1068=item C<PERL_ANYEVENT_EDNS0>
1069
1070Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1071for DNS. This extension is generally useful to reduce DNS traffic, but
1072some (broken) firewalls drop such DNS packets, which is why it is off by
1073default.
1074
1075Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1076EDNS0 in its DNS requests.
1033 1077
1034=back 1078=back
1035 1079
1036=head1 EXAMPLE PROGRAM 1080=head1 EXAMPLE PROGRAM
1037 1081
1123 syswrite $txn->{fh}, $txn->{request} 1167 syswrite $txn->{fh}, $txn->{request}
1124 or die "connection or write error"; 1168 or die "connection or write error";
1125 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r }); 1169 $txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1126 1170
1127Again, C<fh_ready_r> waits till all data has arrived, and then stores the 1171Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1128result and signals any possible waiters that the request ahs finished: 1172result and signals any possible waiters that the request has finished:
1129 1173
1130 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf}; 1174 sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1131 1175
1132 if (end-of-file or data complete) { 1176 if (end-of-file or data complete) {
1133 $txn->{result} = $txn->{buf}; 1177 $txn->{result} = $txn->{buf};
1141 1185
1142 $txn->{finished}->recv; 1186 $txn->{finished}->recv;
1143 return $txn->{result}; 1187 return $txn->{result};
1144 1188
1145The actual code goes further and collects all errors (C<die>s, exceptions) 1189The actual code goes further and collects all errors (C<die>s, exceptions)
1146that occured during request processing. The C<result> method detects 1190that occurred during request processing. The C<result> method detects
1147whether an exception as thrown (it is stored inside the $txn object) 1191whether an exception as thrown (it is stored inside the $txn object)
1148and just throws the exception, which means connection errors and other 1192and just throws the exception, which means connection errors and other
1149problems get reported tot he code that tries to use the result, not in a 1193problems get reported tot he code that tries to use the result, not in a
1150random callback. 1194random callback.
1151 1195
1197of various event loops I prepared some benchmarks. 1241of various event loops I prepared some benchmarks.
1198 1242
1199=head2 BENCHMARKING ANYEVENT OVERHEAD 1243=head2 BENCHMARKING ANYEVENT OVERHEAD
1200 1244
1201Here is a benchmark of various supported event models used natively and 1245Here is a benchmark of various supported event models used natively and
1202through anyevent. The benchmark creates a lot of timers (with a zero 1246through AnyEvent. The benchmark creates a lot of timers (with a zero
1203timeout) and I/O watchers (watching STDOUT, a pty, to become writable, 1247timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1204which it is), lets them fire exactly once and destroys them again. 1248which it is), lets them fire exactly once and destroys them again.
1205 1249
1206Source code for this benchmark is found as F<eg/bench> in the AnyEvent 1250Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1207distribution. 1251distribution.
1330 1374
1331=back 1375=back
1332 1376
1333=head2 BENCHMARKING THE LARGE SERVER CASE 1377=head2 BENCHMARKING THE LARGE SERVER CASE
1334 1378
1335This benchmark atcually benchmarks the event loop itself. It works by 1379This benchmark actually benchmarks the event loop itself. It works by
1336creating a number of "servers": each server consists of a socketpair, a 1380creating a number of "servers": each server consists of a socket pair, a
1337timeout watcher that gets reset on activity (but never fires), and an I/O 1381timeout watcher that gets reset on activity (but never fires), and an I/O
1338watcher waiting for input on one side of the socket. Each time the socket 1382watcher waiting for input on one side of the socket. Each time the socket
1339watcher reads a byte it will write that byte to a random other "server". 1383watcher reads a byte it will write that byte to a random other "server".
1340 1384
1341The effect is that there will be a lot of I/O watchers, only part of which 1385The effect is that there will be a lot of I/O watchers, only part of which
1342are active at any one point (so there is a constant number of active 1386are active at any one point (so there is a constant number of active
1343fds for each loop iterstaion, but which fds these are is random). The 1387fds for each loop iteration, but which fds these are is random). The
1344timeout is reset each time something is read because that reflects how 1388timeout is reset each time something is read because that reflects how
1345most timeouts work (and puts extra pressure on the event loops). 1389most timeouts work (and puts extra pressure on the event loops).
1346 1390
1347In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100 1391In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1348(1%) are active. This mirrors the activity of large servers with many 1392(1%) are active. This mirrors the activity of large servers with many
1349connections, most of which are idle at any one point in time. 1393connections, most of which are idle at any one point in time.
1350 1394
1351Source code for this benchmark is found as F<eg/bench2> in the AnyEvent 1395Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1352distribution. 1396distribution.
1354=head3 Explanation of the columns 1398=head3 Explanation of the columns
1355 1399
1356I<sockets> is the number of sockets, and twice the number of "servers" (as 1400I<sockets> is the number of sockets, and twice the number of "servers" (as
1357each server has a read and write socket end). 1401each server has a read and write socket end).
1358 1402
1359I<create> is the time it takes to create a socketpair (which is 1403I<create> is the time it takes to create a socket pair (which is
1360nontrivial) and two watchers: an I/O watcher and a timeout watcher. 1404nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1361 1405
1362I<request>, the most important value, is the time it takes to handle a 1406I<request>, the most important value, is the time it takes to handle a
1363single "request", that is, reading the token from the pipe and forwarding 1407single "request", that is, reading the token from the pipe and forwarding
1364it to another server. This includes deleting the old timeout and creating 1408it to another server. This includes deleting the old timeout and creating
1487probably even less useful to an attacker than PERL_ANYEVENT_MODEL). 1531probably even less useful to an attacker than PERL_ANYEVENT_MODEL).
1488 1532
1489 1533
1490=head1 SEE ALSO 1534=head1 SEE ALSO
1491 1535
1536Utility functions: L<AnyEvent::Util>.
1537
1492Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>, 1538Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1493L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. 1539L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1494 1540
1495Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>, 1541Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1496L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, 1542L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1497L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>, 1543L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1498L<AnyEvent::Impl::POE>. 1544L<AnyEvent::Impl::POE>.
1499 1545
1546Non-blocking file handles, sockets, TCP clients and
1547servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
1548
1549Asynchronous DNS: L<AnyEvent::DNS>.
1550
1500Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>, 1551Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1501 1552
1502Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>. 1553Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1503 1554
1504 1555
1505=head1 AUTHOR 1556=head1 AUTHOR
1506 1557
1507 Marc Lehmann <schmorp@schmorp.de> 1558 Marc Lehmann <schmorp@schmorp.de>

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