[ViewVC] Diff of: cvs/AnyEvent-MP/MP.pm

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.30 by root, Tue Aug 4 23:35:51 2009 UTC vs.
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC

…		…
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's noderef
10	NODE # returns this node's noderef	10	NODE # returns this node's noderef
11	NODE $port # returns the noderef of the port	11	NODE $port # returns the noderef of the port
12		12
		13	$SELF # receiving/own port id in rcv callbacks
		14
		15	# ports are message endpoints
		16
		17	# sending messages
13	snd $port, type => data...;	18	snd $port, type => data...;
		19	snd $port, @msg;
		20	snd @msg_with_first_element_being_a_port;
14		21
15	$SELF # receiving/own port id in rcv callbacks	22	# miniports
		23	my $miniport = port { my @msg = @_; 0 };
16		24
		25	# full ports
		26	my $port = port;
17	rcv $port, smartmatch => $cb->($port, @msg);	27	rcv $port, smartmatch => $cb->(@msg);
18
19	# examples:
20	rcv $port2, ping => sub { snd $_[0], "pong"; 0 };	28	rcv $port, ping => sub { snd $_[0], "pong"; 0 };
21	rcv $port1, pong => sub { warn "pong received\n" };	29	rcv $port, pong => sub { warn "pong received\n"; 0 };
22	snd $port2, ping => $port1;	30
		31	# remote ports
		32	my $port = spawn $node, $initfunc, @initdata;
23		33
24	# more, smarter, matches (_any_ is exported by this module)	34	# more, smarter, matches (_any_ is exported by this module)
25	rcv $port, [child_died => $pid] => sub { ...	35	rcv $port, [child_died => $pid] => sub { ...
26	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3	36	rcv $port, [_any_, _any_, 3] => sub { .. $_[2] is 3
		37
		38	# monitoring
		39	mon $port, $cb->(@msg) # callback is invoked on death
		40	mon $port, $otherport # kill otherport on abnormal death
		41	mon $port, $otherport, @msg # send message on death
27		42
28	=head1 DESCRIPTION	43	=head1 DESCRIPTION
29		44
30	This module (-family) implements a simple message passing framework.	45	This module (-family) implements a simple message passing framework.
31		46
…		…
100		115
101	use AE ();	116	use AE ();
102		117
103	use base "Exporter";	118	use base "Exporter";
104		119
105	our $VERSION = '0.1';	120	our $VERSION = $AnyEvent::MP::Base::VERSION;
		121
106	our @EXPORT = qw(	122	our @EXPORT = qw(
107	NODE $NODE *SELF node_of _any_	123	NODE $NODE *SELF node_of _any_
108	resolve_node	124	resolve_node initialise_node
109	become_slave become_public
110	snd rcv mon kil reg psub	125	snd rcv mon kil reg psub spawn
111	port	126	port
112	);	127	);
113		128
114	our $SELF;	129	our $SELF;
115		130
…		…
124	The C<NODE> function returns, and the C<$NODE> variable contains	139	The C<NODE> function returns, and the C<$NODE> variable contains
125	the noderef of the local node. The value is initialised by a call	140	the noderef of the local node. The value is initialised by a call
126	to C<become_public> or C<become_slave>, after which all local port	141	to C<become_public> or C<become_slave>, after which all local port
127	identifiers become invalid.	142	identifiers become invalid.
128		143
129	=item $noderef = node_of $portid	144	=item $noderef = node_of $port
130		145
131	Extracts and returns the noderef from a portid or a noderef.	146	Extracts and returns the noderef from a portid or a noderef.
		147
		148	=item initialise_node $noderef, $seednode, $seednode...
		149
		150	=item initialise_node "slave/", $master, $master...
		151
		152	Before a node can talk to other nodes on the network it has to initialise
		153	itself - the minimum a node needs to know is it's own name, and optionally
		154	it should know the noderefs of some other nodes in the network.
		155
		156	This function initialises a node - it must be called exactly once (or
		157	never) before calling other AnyEvent::MP functions.
		158
		159	All arguments are noderefs, which can be either resolved or unresolved.
		160
		161	There are two types of networked nodes, public nodes and slave nodes:
		162
		163	=over 4
		164
		165	=item public nodes
		166
		167	For public nodes, C<$noderef> must either be a (possibly unresolved)
		168	noderef, in which case it will be resolved, or C<undef> (or missing), in
		169	which case the noderef will be guessed.
		170
		171	Afterwards, the node will bind itself on all endpoints and try to connect
		172	to all additional C<$seednodes> that are specified. Seednodes are optional
		173	and can be used to quickly bootstrap the node into an existing network.
		174
		175	=item slave nodes
		176
		177	When the C<$noderef> is the special string C<slave/>, then the node will
		178	become a slave node. Slave nodes cannot be contacted from outside and will
		179	route most of their traffic to the master node that they attach to.
		180
		181	At least one additional noderef is required: The node will try to connect
		182	to all of them and will become a slave attached to the first node it can
		183	successfully connect to.
		184
		185	=back
		186
		187	This function will block until all nodes have been resolved and, for slave
		188	nodes, until it has successfully established a connection to a master
		189	server.
		190
		191	Example: become a public node listening on the default node.
		192
		193	initialise_node;
		194
		195	Example: become a public node, and try to contact some well-known master
		196	servers to become part of the network.
		197
		198	initialise_node undef, "master1", "master2";
		199
		200	Example: become a public node listening on port C<4041>.
		201
		202	initialise_node 4041;
		203
		204	Example: become a public node, only visible on localhost port 4044.
		205
		206	initialise_node "locahost:4044";
		207
		208	Example: become a slave node to any of the specified master servers.
		209
		210	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
132		211
133	=item $cv = resolve_node $noderef	212	=item $cv = resolve_node $noderef
134		213
135	Takes an unresolved node reference that may contain hostnames and	214	Takes an unresolved node reference that may contain hostnames and
136	abbreviated IDs, resolves all of them and returns a resolved node	215	abbreviated IDs, resolves all of them and returns a resolved node
…		…
168		247
169	Due to some quirks in how perl exports variables, it is impossible to	248	Due to some quirks in how perl exports variables, it is impossible to
170	just export C<$SELF>, all the symbols called C<SELF> are exported by this	249	just export C<$SELF>, all the symbols called C<SELF> are exported by this
171	module, but only C<$SELF> is currently used.	250	module, but only C<$SELF> is currently used.
172		251
173	=item snd $portid, type => @data	252	=item snd $port, type => @data
174		253
175	=item snd $portid, @msg	254	=item snd $port, @msg
176		255
177	Send the given message to the given port ID, which can identify either	256	Send the given message to the given port ID, which can identify either
178	a local or a remote port, and can be either a string or soemthignt hat	257	a local or a remote port, and can be either a string or soemthignt hat
179	stringifies a sa port ID (such as a port object :).	258	stringifies a sa port ID (such as a port object :).
180		259
…		…
190	JSON is used, then only strings, numbers and arrays and hashes consisting	269	JSON is used, then only strings, numbers and arrays and hashes consisting
191	of those are allowed (no objects). When Storable is used, then anything	270	of those are allowed (no objects). When Storable is used, then anything
192	that Storable can serialise and deserialise is allowed, and for the local	271	that Storable can serialise and deserialise is allowed, and for the local
193	node, anything can be passed.	272	node, anything can be passed.
194		273
195	=item kil $portid[, @reason]	274	=item $local_port = port
196		275
197	Kill the specified port with the given C<@reason>.	276	Create a new local port object that can be used either as a pattern
		277	matching port ("full port") or a single-callback port ("miniport"),
		278	depending on how C<rcv> callbacks are bound to the object.
198		279
199	If no C<@reason> is specified, then the port is killed "normally" (linked	280	=item $port = port { my @msg = @_; $finished }
200	ports will not be kileld, or even notified).
201		281
202	Otherwise, linked ports get killed with the same reason (second form of	282	Creates a "miniport", that is, a very lightweight port without any pattern
203	C<mon>, see below).	283	matching behind it, and returns its ID. Semantically the same as creating
		284	a port and calling C<rcv $port, $callback> on it.
204		285
205	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	286	The block will be called for every message received on the port. When the
206	will be reported as reason C<< die => $@ >>.	287	callback returns a true value its job is considered "done" and the port
		288	will be destroyed. Otherwise it will stay alive.
207		289
208	Transport/communication errors are reported as C<< transport_error =>	290	The message will be passed as-is, no extra argument (i.e. no port id) will
209	$message >>.	291	be passed to the callback.
210		292
		293	If you need the local port id in the callback, this works nicely:
		294
		295	my $port; $port = port {
		296	snd $otherport, reply => $port;
		297	};
		298
		299	=cut
		300
		301	sub rcv($@);
		302
		303	sub port(;&) {
		304	my $id = "$UNIQ." . $ID++;
		305	my $port = "$NODE#$id";
		306
		307	if (@_) {
		308	rcv $port, shift;
		309	} else {
		310	$PORT{$id} = sub { }; # nop
		311	}
		312
		313	$port
		314	}
		315
		316	=item reg $port, $name
		317
		318	=item reg $name
		319
		320	Registers the given port (or C<$SELF><<< if missing) under the name
		321	C<$name>. If the name already exists it is replaced.
		322
		323	A port can only be registered under one well known name.
		324
		325	A port automatically becomes unregistered when it is killed.
		326
		327	=cut
		328
		329	sub reg(@) {
		330	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		331
		332	$REG{$_[0]} = $port;
		333	}
		334
		335	=item rcv $port, $callback->(@msg)
		336
		337	Replaces the callback on the specified miniport (after converting it to
		338	one if required).
		339
		340	=item rcv $port, tagstring => $callback->(@msg), ...
		341
		342	=item rcv $port, $smartmatch => $callback->(@msg), ...
		343
		344	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		345
		346	Register callbacks to be called on matching messages on the given full
		347	port (after converting it to one if required) and return the port.
		348
		349	The callback has to return a true value when its work is done, after
		350	which is will be removed, or a false value in which case it will stay
		351	registered.
		352
		353	The global C<$SELF> (exported by this module) contains C<$port> while
		354	executing the callback.
		355
		356	Runtime errors during callback execution will result in the port being
		357	C<kil>ed.
		358
		359	If the match is an array reference, then it will be matched against the
		360	first elements of the message, otherwise only the first element is being
		361	matched.
		362
		363	Any element in the match that is specified as C<_any_> (a function
		364	exported by this module) matches any single element of the message.
		365
		366	While not required, it is highly recommended that the first matching
		367	element is a string identifying the message. The one-string-only match is
		368	also the most efficient match (by far).
		369
		370	Example: create a port and bind receivers on it in one go.
		371
		372	my $port = rcv port,
		373	msg1 => sub { ...; 0 },
		374	msg2 => sub { ...; 0 },
		375	;
		376
		377	Example: create a port, bind receivers and send it in a message elsewhere
		378	in one go:
		379
		380	snd $otherport, reply =>
		381	rcv port,
		382	msg1 => sub { ...; 0 },
		383	...
		384	;
		385
		386	=cut
		387
		388	sub rcv($@) {
		389	my $port = shift;
		390	my ($noderef, $portid) = split /#/, $port, 2;
		391
		392	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		393	or Carp::croak "$port: rcv can only be called on local ports, caught";
		394
		395	if (@_ == 1) {
		396	my $cb = shift;
		397	delete $PORT_DATA{$portid};
		398	$PORT{$portid} = sub {
		399	local $SELF = $port;
		400	eval {
		401	&$cb
		402	and kil $port;
		403	};
		404	_self_die if $@;
		405	};
		406	} else {
		407	my $self = $PORT_DATA{$portid} \|\|= do {
		408	my $self = bless {
		409	id => $port,
		410	}, "AnyEvent::MP::Port";
		411
		412	$PORT{$portid} = sub {
		413	local $SELF = $port;
		414
		415	eval {
		416	for (@{ $self->{rc0}{$_[0]} }) {
		417	$_ && &{$_->[0]}
		418	&& undef $_;
		419	}
		420
		421	for (@{ $self->{rcv}{$_[0]} }) {
		422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		423	&& &{$_->[0]}
		424	&& undef $_;
		425	}
		426
		427	for (@{ $self->{any} }) {
		428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		429	&& &{$_->[0]}
		430	&& undef $_;
		431	}
		432	};
		433	_self_die if $@;
		434	};
		435
		436	$self
		437	};
		438
		439	"AnyEvent::MP::Port" eq ref $self
		440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		441
		442	while (@_) {
		443	my ($match, $cb) = splice @_, 0, 2;
		444
		445	if (!ref $match) {
		446	push @{ $self->{rc0}{$match} }, [$cb];
		447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		448	my ($type, @match) = @$match;
		449	@match
		450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
		452	} else {
		453	push @{ $self->{any} }, [$cb, $match];
		454	}
		455	}
		456	}
		457
		458	$port
		459	}
		460
		461	=item $closure = psub { BLOCK }
		462
		463	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
		464	closure is executed, sets up the environment in the same way as in C<rcv>
		465	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
		466
		467	This is useful when you register callbacks from C<rcv> callbacks:
		468
		469	rcv delayed_reply => sub {
		470	my ($delay, @reply) = @_;
		471	my $timer = AE::timer $delay, 0, psub {
		472	snd @reply, $SELF;
		473	};
		474	};
		475
		476	=cut
		477
		478	sub psub(&) {
		479	my $cb = shift;
		480
		481	my $port = $SELF
		482	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
		483
		484	sub {
		485	local $SELF = $port;
		486
		487	if (wantarray) {
		488	my @res = eval { &$cb };
		489	_self_die if $@;
		490	@res
		491	} else {
		492	my $res = eval { &$cb };
		493	_self_die if $@;
		494	$res
		495	}
		496	}
		497	}
		498
211	=item $guard = mon $portid, $cb->(@reason)	499	=item $guard = mon $port, $cb->(@reason)
212		500
213	=item $guard = mon $portid, $otherport	501	=item $guard = mon $port, $rcvport
214		502
		503	=item $guard = mon $port
		504
215	=item $guard = mon $portid, $otherport, @msg	505	=item $guard = mon $port, $rcvport, @msg
216		506
217	Monitor the given port and do something when the port is killed.	507	Monitor the given port and do something when the port is killed or
		508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
218		510
		511	C<mon> effectively guarantees that, in the absence of hardware failures,
		512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
		518
219	In the first form, the callback is simply called with any number	519	In the first form (callback), the callback is simply called with any
220	of C<@reason> elements (no @reason means that the port was deleted	520	number of C<@reason> elements (no @reason means that the port was deleted
221	"normally"). Note also that I<< the callback B<must> never die >>, so use	521	"normally"). Note also that I<< the callback B<must> never die >>, so use
222	C<eval> if unsure.	522	C<eval> if unsure.
223		523
224	In the second form, the other port will be C<kil>'ed with C<@reason>, iff	524	In the second form (another port given), the other port (C<$rcvport>)
225	a @reason was specified, i.e. on "normal" kils nothing happens, while	525	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
226	under all other conditions, the other port is killed with the same reason.	526	"normal" kils nothing happens, while under all other conditions, the other
		527	port is killed with the same reason.
227		528
		529	The third form (kill self) is the same as the second form, except that
		530	C<$rvport> defaults to C<$SELF>.
		531
228	In the last form, a message of the form C<@msg, @reason> will be C<snd>.	532	In the last form (message), a message of the form C<@msg, @reason> will be
		533	C<snd>.
		534
		535	As a rule of thumb, monitoring requests should always monitor a port from
		536	a local port (or callback). The reason is that kill messages might get
		537	lost, just like any other message. Another less obvious reason is that
		538	even monitoring requests can get lost (for exmaple, when the connection
		539	to the other node goes down permanently). When monitoring a port locally
		540	these problems do not exist.
229		541
230	Example: call a given callback when C<$port> is killed.	542	Example: call a given callback when C<$port> is killed.
231		543
232	mon $port, sub { warn "port died because of <@_>\n" };	544	mon $port, sub { warn "port died because of <@_>\n" };
233		545
234	Example: kill ourselves when C<$port> is killed abnormally.	546	Example: kill ourselves when C<$port> is killed abnormally.
235		547
236	mon $port, $self;	548	mon $port;
237		549
238	Example: send us a restart message another C<$port> is killed.	550	Example: send us a restart message when another C<$port> is killed.
239		551
240	mon $port, $self => "restart";	552	mon $port, $self => "restart";
241		553
242	=cut	554	=cut
243		555
244	sub mon {	556	sub mon {
245	my ($noderef, $port) = split /#/, shift, 2;	557	my ($noderef, $port) = split /#/, shift, 2;
246		558
247	my $node = $NODE{$noderef} \|\| add_node $noderef;	559	my $node = $NODE{$noderef} \|\| add_node $noderef;
248		560
249	my $cb = shift;	561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
250		562
251	unless (ref $cb) {	563	unless (ref $cb) {
252	if (@_) {	564	if (@_) {
253	# send a kill info message	565	# send a kill info message
254	my (@msg) = ($cb, @_);	566	my (@msg) = ($cb, @_);
…		…
285	=cut	597	=cut
286		598
287	sub mon_guard {	599	sub mon_guard {
288	my ($port, @refs) = @_;	600	my ($port, @refs) = @_;
289		601
		602	#TODO: mon-less form?
		603
290	mon $port, sub { 0 && @refs }	604	mon $port, sub { 0 && @refs }
291	}	605	}
292		606
293	=item lnk $port1, $port2	607	=item kil $port[, @reason]
294		608
295	Link two ports. This is simply a shorthand for:	609	Kill the specified port with the given C<@reason>.
296		610
297	mon $port1, $port2;	611	If no C<@reason> is specified, then the port is killed "normally" (linked
298	mon $port2, $port1;	612	ports will not be kileld, or even notified).
299		613
300	It means that if either one is killed abnormally, the other one gets	614	Otherwise, linked ports get killed with the same reason (second form of
301	killed as well.	615	C<mon>, see below).
302		616
303	=item $local_port = port	617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		618	will be reported as reason C<< die => $@ >>.
304		619
305	Create a new local port object that supports message matching.	620	Transport/communication errors are reported as C<< transport_error =>
		621	$message >>.
306		622
307	=item $portid = port { my @msg = @_; $finished }
308
309	Creates a "mini port", that is, a very lightweight port without any
310	pattern matching behind it, and returns its ID.
311
312	The block will be called for every message received on the port. When the
313	callback returns a true value its job is considered "done" and the port
314	will be destroyed. Otherwise it will stay alive.
315
316	The message will be passed as-is, no extra argument (i.e. no port id) will
317	be passed to the callback.
318
319	If you need the local port id in the callback, this works nicely:
320
321	my $port; $port = miniport {
322	snd $otherport, reply => $port;
323	};
324
325	=cut	623	=cut
326		624
327	sub port(;&) {	625	=item $port = spawn $node, $initfunc[, @initdata]
328	my $id = "$UNIQ." . $ID++;
329	my $port = "$NODE#$id";
330		626
331	if (@_) {	627	Creates a port on the node C<$node> (which can also be a port ID, in which
332	my $cb = shift;	628	case it's the node where that port resides).
333	$PORT{$id} = sub {	629
334	local $SELF = $port;	630	The port ID of the newly created port is return immediately, and it is
335	eval {	631	permissible to immediately start sending messages or monitor the port.
336	&$cb	632
337	and kil $id;	633	After the port has been created, the init function is
		634	called. This function must be a fully-qualified function name
		635	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		636	program, use C<::name>.
		637
		638	If the function doesn't exist, then the node tries to C<require>
		639	the package, then the package above the package and so on (e.g.
		640	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		641	exists or it runs out of package names.
		642
		643	The init function is then called with the newly-created port as context
		644	object (C<$SELF>) and the C<@initdata> values as arguments.
		645
		646	A common idiom is to pass your own port, monitor the spawned port, and
		647	in the init function, monitor the original port. This two-way monitoring
		648	ensures that both ports get cleaned up when there is a problem.
		649
		650	Example: spawn a chat server port on C<$othernode>.
		651
		652	# this node, executed from within a port context:
		653	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		654	mon $server;
		655
		656	# init function on C<$othernode>
		657	sub connect {
		658	my ($srcport) = @_;
		659
		660	mon $srcport;
		661
		662	rcv $SELF, sub {
338	};	663	...
339	_self_die if $@;
340	};
341	} else {
342	my $self = bless {
343	id => "$NODE#$id",
344	}, "AnyEvent::MP::Port";
345
346	$PORT_DATA{$id} = $self;
347	$PORT{$id} = sub {
348	local $SELF = $port;
349
350	eval {
351	for (@{ $self->{rc0}{$_[0]} }) {
352	$_ && &{$_->[0]}
353	&& undef $_;
354	}
355
356	for (@{ $self->{rcv}{$_[0]} }) {
357	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
358	&& &{$_->[0]}
359	&& undef $_;
360	}
361
362	for (@{ $self->{any} }) {
363	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
364	&& &{$_->[0]}
365	&& undef $_;
366	}
367	};
368	_self_die if $@;
369	};	664	};
370	}	665	}
371		666
372	$port	667	=cut
		668
		669	sub _spawn {
		670	my $port = shift;
		671	my $init = shift;
		672
		673	local $SELF = "$NODE#$port";
		674	eval {
		675	&{ load_func $init }
		676	};
		677	_self_die if $@;
373	}	678	}
374		679
375	=item reg $portid, $name	680	sub spawn(@) {
		681	my ($noderef, undef) = split /#/, shift, 2;
376		682
377	Registers the given port under the name C<$name>. If the name already	683	my $id = "$RUNIQ." . $ID++;
378	exists it is replaced.
379		684
380	A port can only be registered under one well known name.	685	$_[0] =~ /::/
		686	or Carp::croak "spawn init function must be a fully-qualified name, caught";
381		687
382	A port automatically becomes unregistered when it is killed.	688	($NODE{$noderef} \|\| add_node $noderef)
		689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
383		690
384	=cut	691	"$noderef#$id"
385
386	sub reg(@) {
387	my ($portid, $name) = @_;
388
389	$REG{$name} = $portid;
390	}	692	}
391
392	=item rcv $portid, tagstring => $callback->(@msg), ...
393
394	=item rcv $portid, $smartmatch => $callback->(@msg), ...
395
396	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
397
398	Register callbacks to be called on matching messages on the given port.
399
400	The callback has to return a true value when its work is done, after
401	which is will be removed, or a false value in which case it will stay
402	registered.
403
404	The global C<$SELF> (exported by this module) contains C<$portid> while
405	executing the callback.
406
407	Runtime errors wdurign callback execution will result in the port being
408	C<kil>ed.
409
410	If the match is an array reference, then it will be matched against the
411	first elements of the message, otherwise only the first element is being
412	matched.
413
414	Any element in the match that is specified as C<_any_> (a function
415	exported by this module) matches any single element of the message.
416
417	While not required, it is highly recommended that the first matching
418	element is a string identifying the message. The one-string-only match is
419	also the most efficient match (by far).
420
421	=cut
422
423	sub rcv($@) {
424	my ($noderef, $port) = split /#/, shift, 2;
425
426	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
427	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
428
429	my $self = $PORT_DATA{$port}
430	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
431
432	"AnyEvent::MP::Port" eq ref $self
433	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
434
435	while (@_) {
436	my ($match, $cb) = splice @_, 0, 2;
437
438	if (!ref $match) {
439	push @{ $self->{rc0}{$match} }, [$cb];
440	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
441	my ($type, @match) = @$match;
442	@match
443	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
444	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
445	} else {
446	push @{ $self->{any} }, [$cb, $match];
447	}
448	}
449	}
450
451	=item $closure = psub { BLOCK }
452
453	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
454	closure is executed, sets up the environment in the same way as in C<rcv>
455	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
456
457	This is useful when you register callbacks from C<rcv> callbacks:
458
459	rcv delayed_reply => sub {
460	my ($delay, @reply) = @_;
461	my $timer = AE::timer $delay, 0, psub {
462	snd @reply, $SELF;
463	};
464	};
465
466	=cut
467
468	sub psub(&) {
469	my $cb = shift;
470
471	my $port = $SELF
472	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
473
474	sub {
475	local $SELF = $port;
476
477	if (wantarray) {
478	my @res = eval { &$cb };
479	_self_die if $@;
480	@res
481	} else {
482	my $res = eval { &$cb };
483	_self_die if $@;
484	$res
485	}
486	}
487	}
488
489	=back
490
491	=head1 FUNCTIONS FOR NODES
492
493	=over 4
494
495	=item become_public $noderef
496
497	Tells the node to become a public node, i.e. reachable from other nodes.
498
499	The first argument is the (unresolved) node reference of the local node
500	(if missing then the empty string is used).
501
502	It is quite common to not specify anything, in which case the local node
503	tries to listen on the default port, or to only specify a port number, in
504	which case AnyEvent::MP tries to guess the local addresses.
505
506	=cut
507		693
508	=back	694	=back
509		695
510	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
511		697
…		…
553		739
554	=back	740	=back
555		741
556	=head1 AnyEvent::MP vs. Distributed Erlang	742	=head1 AnyEvent::MP vs. Distributed Erlang
557		743
558	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node	744	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
559	== aemp node, erlang process == aemp port), so many of the documents and	745	== aemp node, Erlang process == aemp port), so many of the documents and
560	programming techniques employed by erlang apply to AnyEvent::MP. Here is a	746	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
561	sample:	747	sample:
562		748
563	http://www.erlang.se/doc/programming_rules.shtml	749	http://www.Erlang.se/doc/programming_rules.shtml
564	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	750	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
565	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6	751	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6
566	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5	752	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
567		753
568	Despite the similarities, there are also some important differences:	754	Despite the similarities, there are also some important differences:
569		755
570	=over 4	756	=over 4
571		757
…		…
582		768
583	Erlang uses processes that selctively receive messages, and therefore	769	Erlang uses processes that selctively receive messages, and therefore
584	needs a queue. AEMP is event based, queuing messages would serve no useful	770	needs a queue. AEMP is event based, queuing messages would serve no useful
585	purpose.	771	purpose.
586		772
587	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).	773	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
588		774
589	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
590		776
591	Sending messages in erlang is synchronous and blocks the process. AEMP	777	Sending messages in Erlang is synchronous and blocks the process. AEMP
592	sends are immediate, connection establishment is handled in the	778	sends are immediate, connection establishment is handled in the
593	background.	779	background.
594		780
595	=item * Erlang can silently lose messages, AEMP cannot.	781	=item * Erlang can silently lose messages, AEMP cannot.
596		782
…		…
599	and c, and the other side only receives messages a and c).	785	and c, and the other side only receives messages a and c).
600		786
601	AEMP guarantees correct ordering, and the guarantee that there are no	787	AEMP guarantees correct ordering, and the guarantee that there are no
602	holes in the message sequence.	788	holes in the message sequence.
603		789
604	=item * In erlang, processes can be declared dead and later be found to be	790	=item * In Erlang, processes can be declared dead and later be found to be
605	alive.	791	alive.
606		792
607	In erlang it can happen that a monitored process is declared dead and	793	In Erlang it can happen that a monitored process is declared dead and
608	linked processes get killed, but later it turns out that the process is	794	linked processes get killed, but later it turns out that the process is
609	still alive - and can receive messages.	795	still alive - and can receive messages.
610		796
611	In AEMP, when port monitoring detects a port as dead, then that port will	797	In AEMP, when port monitoring detects a port as dead, then that port will
612	eventually be killed - it cannot happen that a node detects a port as dead	798	eventually be killed - it cannot happen that a node detects a port as dead
613	and then later sends messages to it, finding it is still alive.	799	and then later sends messages to it, finding it is still alive.
614		800
615	=item * Erlang can send messages to the wrong port, AEMP does not.	801	=item * Erlang can send messages to the wrong port, AEMP does not.
616		802
617	In erlang it is quite possible that a node that restarts reuses a process	803	In Erlang it is quite possible that a node that restarts reuses a process
618	ID known to other nodes for a completely different process, causing	804	ID known to other nodes for a completely different process, causing
619	messages destined for that process to end up in an unrelated process.	805	messages destined for that process to end up in an unrelated process.
620		806
621	AEMP never reuses port IDs, so old messages or old port IDs floating	807	AEMP never reuses port IDs, so old messages or old port IDs floating
622	around in the network will not be sent to an unrelated port.	808	around in the network will not be sent to an unrelated port.
…		…
628	securely authenticate nodes.	814	securely authenticate nodes.
629		815
630	=item * The AEMP protocol is optimised for both text-based and binary	816	=item * The AEMP protocol is optimised for both text-based and binary
631	communications.	817	communications.
632		818
633	The AEMP protocol, unlike the erlang protocol, supports both	819	The AEMP protocol, unlike the Erlang protocol, supports both
634	language-independent text-only protocols (good for debugging) and binary,	820	language-independent text-only protocols (good for debugging) and binary,
635	language-specific serialisers (e.g. Storable).	821	language-specific serialisers (e.g. Storable).
636		822
637	It has also been carefully designed to be implementable in other languages	823	It has also been carefully designed to be implementable in other languages
638	with a minimum of work while gracefully degrading fucntionality to make the	824	with a minimum of work while gracefully degrading fucntionality to make the
639	protocol simple.	825	protocol simple.
640		826
		827	=item * AEMP has more flexible monitoring options than Erlang.
		828
		829	In Erlang, you can chose to receive I<all> exit signals as messages
		830	or I<none>, there is no in-between, so monitoring single processes is
		831	difficult to implement. Monitoring in AEMP is more flexible than in
		832	Erlang, as one can choose between automatic kill, exit message or callback
		833	on a per-process basis.
		834
		835	=item * Erlang tries to hide remote/local connections, AEMP does not.
		836
		837	Monitoring in Erlang is not an indicator of process death/crashes,
		838	as linking is (except linking is unreliable in Erlang).
		839
		840	In AEMP, you don't "look up" registered port names or send to named ports
		841	that might or might not be persistent. Instead, you normally spawn a port
		842	on the remote node. The init function monitors the you, and you monitor
		843	the remote port. Since both monitors are local to the node, they are much
		844	more reliable.
		845
		846	This also saves round-trips and avoids sending messages to the wrong port
		847	(hard to do in Erlang).
		848
641	=back	849	=back
642		850
643	=head1 SEE ALSO	851	=head1 SEE ALSO
644		852
645	L<AnyEvent>.	853	L<AnyEvent>.

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Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC