AnyEvent-MP/MP.pm

=head1 NAME

AnyEvent::MP - multi-processing/message-passing framework

=head1 SYNOPSIS

   use AnyEvent::MP;

   $NODE      # contains this node's noderef
   NODE       # returns this node's noderef
   NODE $port # returns the noderef of the port

   snd $port, type => data...;

   $SELF      # receiving/own port id in rcv callbacks

   rcv $port, smartmatch => $cb->($port, @msg);

   # examples:
   rcv $port2, ping => sub { snd $_[0], "pong"; 0 };
   rcv $port1, pong => sub { warn "pong received\n" };
   snd $port2, ping => $port1;

   # more, smarter, matches (_any_ is exported by this module)
   rcv $port, [child_died => $pid] => sub { ...
   rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3

=head1 DESCRIPTION

This module (-family) implements a simple message passing framework.

Despite its simplicity, you can securely message other processes running
on the same or other hosts.

For an introduction to this module family, see the L<AnyEvent::MP::Intro>
manual page.

At the moment, this module family is severly broken and underdocumented,
so do not use. This was uploaded mainly to reserve the CPAN namespace -
stay tuned! The basic API should be finished, however.

=head1 CONCEPTS

=over 4

=item port

A port is something you can send messages to with the C<snd> function, and
you can register C<rcv> handlers with. All C<rcv> handlers will receive
messages they match, messages will not be queued.

=item port id - C<noderef#portname>

A port id is always the noderef, a hash-mark (C<#>) as separator, followed
by a port name (a printable string of unspecified format).

=item node

A node is a single process containing at least one port - the node
port. You can send messages to node ports to let them create new ports,
among other things.

Initially, nodes are either private (single-process only) or hidden
(connected to a master node only). Only when they epxlicitly "become
public" can you send them messages from unrelated other nodes.

=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>

A noderef is a string that either uniquely identifies a given node (for
private and hidden nodes), or contains a recipe on how to reach a given
node (for public nodes).

=back

=head1 VARIABLES/FUNCTIONS

=over 4

=cut

package AnyEvent::MP;

use AnyEvent::MP::Base;

use common::sense;

use Carp ();

use AE ();

use base "Exporter";

our $VERSION = '0.02';
our @EXPORT = qw(
   NODE $NODE *SELF node_of _any_
   become_slave become_public
   snd rcv mon kil reg psub
   port
);

our $SELF;

sub _self_die() {
   my $msg = $@;
   $msg =~ s/\n+$// unless ref $msg;
   kil $SELF, die => $msg;
}

=item $thisnode = NODE / $NODE

The C<NODE> function returns, and the C<$NODE> variable contains
the noderef of the local node. The value is initialised by a call
to C<become_public> or C<become_slave>, after which all local port
identifiers become invalid.

=item $noderef = node_of $portid

Extracts and returns the noderef from a portid or a noderef.

=item $SELF

Contains the current port id while executing C<rcv> callbacks or C<psub>
blocks.

=item SELF, %SELF, @SELF...

Due to some quirks in how perl exports variables, it is impossible to
just export C<$SELF>, all the symbols called C<SELF> are exported by this
module, but only C<$SELF> is currently used.

=item snd $portid, type => @data

=item snd $portid, @msg

Send the given message to the given port ID, which can identify either
a local or a remote port, and can be either a string or soemthignt hat
stringifies a sa port ID (such as a port object :).

While the message can be about anything, it is highly recommended to use a
string as first element (a portid, or some word that indicates a request
type etc.).

The message data effectively becomes read-only after a call to this
function: modifying any argument is not allowed and can cause many
problems.

The type of data you can transfer depends on the transport protocol: when
JSON is used, then only strings, numbers and arrays and hashes consisting
of those are allowed (no objects). When Storable is used, then anything
that Storable can serialise and deserialise is allowed, and for the local
node, anything can be passed.

=item kil $portid[, @reason]

Kill the specified port with the given C<@reason>.

If no C<@reason> is specified, then the port is killed "normally" (linked
ports will not be kileld, or even notified).

Otherwise, linked ports get killed with the same reason (second form of
C<mon>, see below).

Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
will be reported as reason C<< die => $@ >>.

Transport/communication errors are reported as C<< transport_error =>
$message >>.

=item $guard = mon $portid, $cb->(@reason)

=item $guard = mon $portid, $otherport

=item $guard = mon $portid, $otherport, @msg

Monitor the given port and do something when the port is killed.

In the first form, the callback is simply called with any number
of C<@reason> elements (no @reason means that the port was deleted
"normally"). Note also that I<< the callback B<must> never die >>, so use
C<eval> if unsure.

In the second form, the other port will be C<kil>'ed with C<@reason>, iff
a @reason was specified, i.e. on "normal" kils nothing happens, while
under all other conditions, the other port is killed with the same reason.

In the last form, a message of the form C<@msg, @reason> will be C<snd>.

Example: call a given callback when C<$port> is killed.

   mon $port, sub { warn "port died because of <@_>\n" };

Example: kill ourselves when C<$port> is killed abnormally.

   mon $port, $self;

Example: send us a restart message another C<$port> is killed.

   mon $port, $self => "restart";

=cut

sub mon {
   my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);

   my $node = $NODE{$noderef} || add_node $noderef;

   #TODO: ports must not be references
   if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
      if (@_) {
         # send a kill info message
         my (@msg) = ($cb, @_);
         $cb = sub { snd @msg, @_ };
      } else {
         # simply kill other port
         my $port = $cb;
         $cb = sub { kil $port, @_ if @_ };
      }
   }

   $node->monitor ($port, $cb);

   defined wantarray
      and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
}

=item $guard = mon_guard $port, $ref, $ref...

Monitors the given C<$port> and keeps the passed references. When the port
is killed, the references will be freed.

Optionally returns a guard that will stop the monitoring.

This function is useful when you create e.g. timers or other watchers and
want to free them when the port gets killed:

  $port->rcv (start => sub {
     my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
        undef $timer if 0.9 < rand;
     });
  });

=cut

sub mon_guard {
   my ($port, @refs) = @_;

   mon $port, sub { 0 && @refs }
}

=item $local_port = port

Create a new local port object that supports message matching.

=item $portid = port { my @msg = @_; $finished }

Creates a "mini port", that is, a very lightweight port without any
pattern matching behind it, and returns its ID.

The block will be called for every message received on the port. When the
callback returns a true value its job is considered "done" and the port
will be destroyed. Otherwise it will stay alive.

The message will be passed as-is, no extra argument (i.e. no port id) will
be passed to the callback.

If you need the local port id in the callback, this works nicely:

   my $port; $port = miniport {
      snd $otherport, reply => $port;
   };

=cut

sub port(;&) {
   my $id = "$UNIQ." . $ID++;
   my $port = "$NODE#$id";

   if (@_) {
      my $cb = shift;
      $PORT{$id} = sub {
         local $SELF = $port;
         eval {
            &$cb
               and kil $id;
         };
         _self_die if $@;
      };
   } else {
      my $self = bless {
         id    => "$NODE#$id",
      }, "AnyEvent::MP::Port";

      $PORT_DATA{$id} = $self;
      $PORT{$id} = sub {
         local $SELF = $port;

         eval {
            for (@{ $self->{rc0}{$_[0]} }) {
               $_ && &{$_->[0]}
                  && undef $_;
            }

            for (@{ $self->{rcv}{$_[0]} }) {
               $_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
                  && &{$_->[0]}
                  && undef $_;
            }

            for (@{ $self->{any} }) {
               $_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
                  && &{$_->[0]}
                  && undef $_;
            }
         };
         _self_die if $@;
      };
   }

   $port
}

=item reg $portid, $name

Registers the given port under the name C<$name>. If the name already
exists it is replaced.

A port can only be registered under one well known name.

A port automatically becomes unregistered when it is killed.

=cut

sub reg(@) {
   my ($portid, $name) = @_;

   $REG{$name} = $portid;
}

=item rcv $portid, tagstring        => $callback->(@msg), ...

=item rcv $portid, $smartmatch      => $callback->(@msg), ...

=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...

Register callbacks to be called on matching messages on the given port.

The callback has to return a true value when its work is done, after
which is will be removed, or a false value in which case it will stay
registered.

The global C<$SELF> (exported by this module) contains C<$portid> while
executing the callback.

Runtime errors wdurign callback execution will result in the port being
C<kil>ed.

If the match is an array reference, then it will be matched against the
first elements of the message, otherwise only the first element is being
matched.

Any element in the match that is specified as C<_any_> (a function
exported by this module) matches any single element of the message.

While not required, it is highly recommended that the first matching
element is a string identifying the message. The one-string-only match is
also the most efficient match (by far).

=cut

sub rcv($@) {
   my ($noderef, $port) = split /#/, shift, 2;

   ($NODE{$noderef} || add_node $noderef) == $NODE{""}
      or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";

   my $self = $PORT_DATA{$port}
      or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";

   "AnyEvent::MP::Port" eq ref $self
      or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";

   while (@_) {
      my ($match, $cb) = splice @_, 0, 2;

      if (!ref $match) {
         push @{ $self->{rc0}{$match}      }, [$cb];
      } elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
         my ($type, @match) = @$match;
         @match
            ? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
            : push @{ $self->{rc0}{$match->[0]} }, [$cb];
      } else {
         push @{ $self->{any}              }, [$cb, $match];
      }
   }
}

=item $closure = psub { BLOCK }

Remembers C<$SELF> and creates a closure out of the BLOCK. When the
closure is executed, sets up the environment in the same way as in C<rcv>
callbacks, i.e. runtime errors will cause the port to get C<kil>ed.

This is useful when you register callbacks from C<rcv> callbacks:

   rcv delayed_reply => sub {
      my ($delay, @reply) = @_;
      my $timer = AE::timer $delay, 0, psub {
         snd @reply, $SELF;
      };
   };

=cut

sub psub(&) {
   my $cb = shift;

   my $port = $SELF
      or Carp::croak "psub can only be called from within rcv or psub callbacks, not";

   sub {
      local $SELF = $port;

      if (wantarray) {
         my @res = eval { &$cb };
         _self_die if $@;
         @res
      } else {
         my $res = eval { &$cb };
         _self_die if $@;
         $res
      }
   }
}

=back

=head1 FUNCTIONS FOR NODES

=over 4

=item become_public endpoint...

Tells the node to become a public node, i.e. reachable from other nodes.

If no arguments are given, or the first argument is C<undef>, then
AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
local nodename resolves to.

Otherwise the first argument must be an array-reference with transport
endpoints ("ip:port", "hostname:port") or port numbers (in which case the
local nodename is used as hostname). The endpoints are all resolved and
will become the node reference.

=cut

=back

=head1 NODE MESSAGES

Nodes understand the following messages sent to them. Many of them take
arguments called C<@reply>, which will simply be used to compose a reply
message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
the remaining arguments are simply the message data.

=over 4

=cut

=item lookup => $name, @reply

Replies with the port ID of the specified well-known port, or C<undef>.

=item devnull => ...

Generic data sink/CPU heat conversion.

=item relay => $port, @msg

Simply forwards the message to the given port.

=item eval => $string[ @reply]

Evaluates the given string. If C<@reply> is given, then a message of the
form C<@reply, $@, @evalres> is sent.

Example: crash another node.

   snd $othernode, eval => "exit";

=item time => @reply

Replies the the current node time to C<@reply>.

Example: tell the current node to send the current time to C<$myport> in a
C<timereply> message.

   snd $NODE, time => $myport, timereply => 1, 2;
   # => snd $myport, timereply => 1, 2, <time>

=back

=head1 SEE ALSO

L<AnyEvent>.

=head1 AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/

=cut

1

Revision:	1.23
Committed:	Tue Aug 4 18:46:16 2009 UTC (14 years, 9 months ago) by root
Branch:	MAIN
Changes since 1.22:	+5 -2 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			AnyEvent::MP - multi-processing/message-passing framework
4
5			=head1 SYNOPSIS
6
7			use AnyEvent::MP;
8
9	root	1.22	$NODE # contains this node's noderef
10			NODE # returns this node's noderef
11			NODE $port # returns the noderef of the port
12	root	1.2
13			snd $port, type => data...;
14
15	root	1.22	$SELF # receiving/own port id in rcv callbacks
16
17	root	1.2	rcv $port, smartmatch => $cb->($port, @msg);
18
19			# examples:
20			rcv $port2, ping => sub { snd $_[0], "pong"; 0 };
21			rcv $port1, pong => sub { warn "pong received\n" };
22			snd $port2, ping => $port1;
23
24			# more, smarter, matches (_any_ is exported by this module)
25			rcv $port, [child_died => $pid] => sub { ...
26			rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
27
28	root	1.1	=head1 DESCRIPTION
29
30	root	1.2	This module (-family) implements a simple message passing framework.
31
32			Despite its simplicity, you can securely message other processes running
33			on the same or other hosts.
34
35	root	1.23	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
36			manual page.
37
38			At the moment, this module family is severly broken and underdocumented,
39	root	1.21	so do not use. This was uploaded mainly to reserve the CPAN namespace -
40	root	1.23	stay tuned! The basic API should be finished, however.
41	root	1.6
42	root	1.2	=head1 CONCEPTS
43
44			=over 4
45
46			=item port
47
48			A port is something you can send messages to with the C<snd> function, and
49			you can register C<rcv> handlers with. All C<rcv> handlers will receive
50			messages they match, messages will not be queued.
51
52	root	1.3	=item port id - C<noderef#portname>
53	root	1.2
54	root	1.3	A port id is always the noderef, a hash-mark (C<#>) as separator, followed
55			by a port name (a printable string of unspecified format).
56	root	1.2
57			=item node
58
59			A node is a single process containing at least one port - the node
60			port. You can send messages to node ports to let them create new ports,
61			among other things.
62
63			Initially, nodes are either private (single-process only) or hidden
64	root	1.3	(connected to a master node only). Only when they epxlicitly "become
65			public" can you send them messages from unrelated other nodes.
66	root	1.2
67	root	1.5	=item noderef - C<host:port,host:port...>, C<id@noderef>, C<id>
68	root	1.2
69	root	1.3	A noderef is a string that either uniquely identifies a given node (for
70	root	1.2	private and hidden nodes), or contains a recipe on how to reach a given
71			node (for public nodes).
72
73			=back
74
75	root	1.3	=head1 VARIABLES/FUNCTIONS
76	root	1.2
77			=over 4
78
79	root	1.1	=cut
80
81			package AnyEvent::MP;
82
83	root	1.8	use AnyEvent::MP::Base;
84	root	1.2
85	root	1.1	use common::sense;
86
87	root	1.2	use Carp ();
88
89	root	1.1	use AE ();
90
91	root	1.2	use base "Exporter";
92
93	root	1.9	our $VERSION = '0.02';
94	root	1.8	our @EXPORT = qw(
95	root	1.22	NODE $NODE *SELF node_of _any_
96	root	1.8	become_slave become_public
97	root	1.22	snd rcv mon kil reg psub
98			port
99	root	1.8	);
100	root	1.2
101	root	1.22	our $SELF;
102
103			sub _self_die() {
104			my $msg = $@;
105			$msg =~ s/\n+$// unless ref $msg;
106			kil $SELF, die => $msg;
107			}
108
109			=item $thisnode = NODE / $NODE
110
111			The C<NODE> function returns, and the C<$NODE> variable contains
112			the noderef of the local node. The value is initialised by a call
113			to C<become_public> or C<become_slave>, after which all local port
114			identifiers become invalid.
115
116			=item $noderef = node_of $portid
117
118			Extracts and returns the noderef from a portid or a noderef.
119
120			=item $SELF
121
122			Contains the current port id while executing C<rcv> callbacks or C<psub>
123			blocks.
124	root	1.3
125	root	1.22	=item SELF, %SELF, @SELF...
126
127			Due to some quirks in how perl exports variables, it is impossible to
128			just export C<$SELF>, all the symbols called C<SELF> are exported by this
129			module, but only C<$SELF> is currently used.
130	root	1.3
131			=item snd $portid, type => @data
132
133			=item snd $portid, @msg
134
135	root	1.8	Send the given message to the given port ID, which can identify either
136			a local or a remote port, and can be either a string or soemthignt hat
137			stringifies a sa port ID (such as a port object :).
138
139			While the message can be about anything, it is highly recommended to use a
140			string as first element (a portid, or some word that indicates a request
141			type etc.).
142	root	1.3
143			The message data effectively becomes read-only after a call to this
144			function: modifying any argument is not allowed and can cause many
145			problems.
146
147			The type of data you can transfer depends on the transport protocol: when
148			JSON is used, then only strings, numbers and arrays and hashes consisting
149			of those are allowed (no objects). When Storable is used, then anything
150			that Storable can serialise and deserialise is allowed, and for the local
151			node, anything can be passed.
152
153	root	1.22	=item kil $portid[, @reason]
154
155			Kill the specified port with the given C<@reason>.
156
157			If no C<@reason> is specified, then the port is killed "normally" (linked
158			ports will not be kileld, or even notified).
159
160			Otherwise, linked ports get killed with the same reason (second form of
161			C<mon>, see below).
162
163			Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
164			will be reported as reason C<< die => $@ >>.
165
166			Transport/communication errors are reported as C<< transport_error =>
167			$message >>.
168
169			=item $guard = mon $portid, $cb->(@reason)
170	root	1.18
171	root	1.21	=item $guard = mon $portid, $otherport
172
173			=item $guard = mon $portid, $otherport, @msg
174
175	root	1.22	Monitor the given port and do something when the port is killed.
176
177			In the first form, the callback is simply called with any number
178			of C<@reason> elements (no @reason means that the port was deleted
179			"normally"). Note also that I<< the callback B<must> never die >>, so use
180			C<eval> if unsure.
181
182			In the second form, the other port will be C<kil>'ed with C<@reason>, iff
183			a @reason was specified, i.e. on "normal" kils nothing happens, while
184			under all other conditions, the other port is killed with the same reason.
185	root	1.20
186	root	1.22	In the last form, a message of the form C<@msg, @reason> will be C<snd>.
187
188			Example: call a given callback when C<$port> is killed.
189
190			mon $port, sub { warn "port died because of <@_>\n" };
191
192			Example: kill ourselves when C<$port> is killed abnormally.
193
194			mon $port, $self;
195
196			Example: send us a restart message another C<$port> is killed.
197
198			mon $port, $self => "restart";
199	root	1.18
200			=cut
201
202			sub mon {
203	root	1.21	my ($noderef, $port, $cb) = ((split /#/, shift, 2), shift);
204	root	1.18
205	root	1.22	my $node = $NODE{$noderef} \|\| add_node $noderef;
206	root	1.18
207	root	1.21	#TODO: ports must not be references
208			if (!ref $cb or "AnyEvent::MP::Port" eq ref $cb) {
209			if (@_) {
210			# send a kill info message
211			my (@msg) = ($cb, @_);
212			$cb = sub { snd @msg, @_ };
213			} else {
214			# simply kill other port
215			my $port = $cb;
216	root	1.22	$cb = sub { kil $port, @_ if @_ };
217	root	1.21	}
218			}
219	root	1.18
220			$node->monitor ($port, $cb);
221
222			defined wantarray
223			and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }
224			}
225
226	root	1.21	=item $guard = mon_guard $port, $ref, $ref...
227
228			Monitors the given C<$port> and keeps the passed references. When the port
229			is killed, the references will be freed.
230
231			Optionally returns a guard that will stop the monitoring.
232
233			This function is useful when you create e.g. timers or other watchers and
234			want to free them when the port gets killed:
235
236			$port->rcv (start => sub {
237			my $timer; $timer = mon_guard $port, AE::timer 1, 1, sub {
238			undef $timer if 0.9 < rand;
239			});
240			});
241
242			=cut
243
244			sub mon_guard {
245			my ($port, @refs) = @_;
246
247			mon $port, sub { 0 && @refs }
248			}
249
250	root	1.22	=item $local_port = port
251	root	1.2
252	root	1.22	Create a new local port object that supports message matching.
253	root	1.3
254	root	1.22	=item $portid = port { my @msg = @_; $finished }
255	root	1.10
256	root	1.15	Creates a "mini port", that is, a very lightweight port without any
257			pattern matching behind it, and returns its ID.
258
259			The block will be called for every message received on the port. When the
260			callback returns a true value its job is considered "done" and the port
261			will be destroyed. Otherwise it will stay alive.
262
263	root	1.17	The message will be passed as-is, no extra argument (i.e. no port id) will
264	root	1.15	be passed to the callback.
265
266			If you need the local port id in the callback, this works nicely:
267
268			my $port; $port = miniport {
269			snd $otherport, reply => $port;
270			};
271	root	1.10
272			=cut
273
274	root	1.22	sub port(;&) {
275			my $id = "$UNIQ." . $ID++;
276			my $port = "$NODE#$id";
277
278			if (@_) {
279			my $cb = shift;
280			$PORT{$id} = sub {
281			local $SELF = $port;
282			eval {
283			&$cb
284			and kil $id;
285			};
286			_self_die if $@;
287			};
288			} else {
289			my $self = bless {
290			id => "$NODE#$id",
291			}, "AnyEvent::MP::Port";
292
293			$PORT_DATA{$id} = $self;
294			$PORT{$id} = sub {
295			local $SELF = $port;
296
297			eval {
298			for (@{ $self->{rc0}{$_[0]} }) {
299			$_ && &{$_->[0]}
300			&& undef $_;
301			}
302
303			for (@{ $self->{rcv}{$_[0]} }) {
304			$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
305			&& &{$_->[0]}
306			&& undef $_;
307			}
308
309			for (@{ $self->{any} }) {
310			$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
311			&& &{$_->[0]}
312			&& undef $_;
313			}
314			};
315			_self_die if $@;
316			};
317			}
318	root	1.10
319	root	1.22	$port
320	root	1.10	}
321
322	root	1.22	=item reg $portid, $name
323	root	1.8
324	root	1.22	Registers the given port under the name C<$name>. If the name already
325			exists it is replaced.
326	root	1.8
327	root	1.22	A port can only be registered under one well known name.
328	root	1.8
329	root	1.22	A port automatically becomes unregistered when it is killed.
330	root	1.8
331			=cut
332
333	root	1.22	sub reg(@) {
334			my ($portid, $name) = @_;
335	root	1.8
336	root	1.22	$REG{$name} = $portid;
337			}
338	root	1.18
339	root	1.22	=item rcv $portid, tagstring => $callback->(@msg), ...
340	root	1.3
341	root	1.22	=item rcv $portid, $smartmatch => $callback->(@msg), ...
342	root	1.3
343	root	1.22	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
344	root	1.3
345	root	1.22	Register callbacks to be called on matching messages on the given port.
346	root	1.3
347			The callback has to return a true value when its work is done, after
348			which is will be removed, or a false value in which case it will stay
349			registered.
350
351	root	1.22	The global C<$SELF> (exported by this module) contains C<$portid> while
352			executing the callback.
353
354			Runtime errors wdurign callback execution will result in the port being
355			C<kil>ed.
356
357	root	1.3	If the match is an array reference, then it will be matched against the
358			first elements of the message, otherwise only the first element is being
359			matched.
360
361			Any element in the match that is specified as C<_any_> (a function
362			exported by this module) matches any single element of the message.
363
364			While not required, it is highly recommended that the first matching
365			element is a string identifying the message. The one-string-only match is
366			also the most efficient match (by far).
367
368			=cut
369
370			sub rcv($@) {
371	root	1.22	my ($noderef, $port) = split /#/, shift, 2;
372	root	1.3
373	root	1.22	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
374			or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
375
376			my $self = $PORT_DATA{$port}
377			or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
378
379			"AnyEvent::MP::Port" eq ref $self
380			or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
381
382			while (@_) {
383			my ($match, $cb) = splice @_, 0, 2;
384
385			if (!ref $match) {
386			push @{ $self->{rc0}{$match} }, [$cb];
387			} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
388			my ($type, @match) = @$match;
389			@match
390			? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
391			: push @{ $self->{rc0}{$match->[0]} }, [$cb];
392			} else {
393			push @{ $self->{any} }, [$cb, $match];
394			}
395	root	1.3	}
396	root	1.2	}
397
398	root	1.22	=item $closure = psub { BLOCK }
399	root	1.2
400	root	1.22	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
401			closure is executed, sets up the environment in the same way as in C<rcv>
402			callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
403
404			This is useful when you register callbacks from C<rcv> callbacks:
405
406			rcv delayed_reply => sub {
407			my ($delay, @reply) = @_;
408			my $timer = AE::timer $delay, 0, psub {
409			snd @reply, $SELF;
410			};
411			};
412	root	1.3
413	root	1.8	=cut
414	root	1.3
415	root	1.22	sub psub(&) {
416			my $cb = shift;
417	root	1.3
418	root	1.22	my $port = $SELF
419			or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
420	root	1.1
421	root	1.22	sub {
422			local $SELF = $port;
423	root	1.2
424	root	1.22	if (wantarray) {
425			my @res = eval { &$cb };
426			_self_die if $@;
427			@res
428			} else {
429			my $res = eval { &$cb };
430			_self_die if $@;
431			$res
432			}
433			}
434	root	1.2	}
435
436	root	1.8	=back
437
438			=head1 FUNCTIONS FOR NODES
439
440			=over 4
441	root	1.2
442	root	1.8	=item become_public endpoint...
443
444			Tells the node to become a public node, i.e. reachable from other nodes.
445
446			If no arguments are given, or the first argument is C<undef>, then
447			AnyEvent::MP tries to bind on port C<4040> on all IP addresses that the
448			local nodename resolves to.
449
450			Otherwise the first argument must be an array-reference with transport
451			endpoints ("ip:port", "hostname:port") or port numbers (in which case the
452			local nodename is used as hostname). The endpoints are all resolved and
453			will become the node reference.
454	root	1.2
455	root	1.8	=cut
456	root	1.1
457	root	1.4	=back
458
459			=head1 NODE MESSAGES
460
461	root	1.5	Nodes understand the following messages sent to them. Many of them take
462			arguments called C<@reply>, which will simply be used to compose a reply
463			message - C<$reply[0]> is the port to reply to, C<$reply[1]> the type and
464			the remaining arguments are simply the message data.
465	root	1.4
466			=over 4
467
468			=cut
469
470	root	1.22	=item lookup => $name, @reply
471	root	1.3
472	root	1.8	Replies with the port ID of the specified well-known port, or C<undef>.
473	root	1.3
474	root	1.7	=item devnull => ...
475
476			Generic data sink/CPU heat conversion.
477
478	root	1.4	=item relay => $port, @msg
479
480			Simply forwards the message to the given port.
481
482			=item eval => $string[ @reply]
483
484			Evaluates the given string. If C<@reply> is given, then a message of the
485	root	1.5	form C<@reply, $@, @evalres> is sent.
486
487			Example: crash another node.
488
489			snd $othernode, eval => "exit";
490	root	1.4
491			=item time => @reply
492
493			Replies the the current node time to C<@reply>.
494
495	root	1.5	Example: tell the current node to send the current time to C<$myport> in a
496			C<timereply> message.
497
498			snd $NODE, time => $myport, timereply => 1, 2;
499			# => snd $myport, timereply => 1, 2, <time>
500
501	root	1.2	=back
502
503	root	1.1	=head1 SEE ALSO
504
505			L<AnyEvent>.
506
507			=head1 AUTHOR
508
509			Marc Lehmann <schmorp@schmorp.de>
510			http://home.schmorp.de/
511
512			=cut
513
514			1
515