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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.31 by root, Wed Aug 5 19:55:58 2009 UTC vs.
Revision 1.44 by root, Wed Aug 12 21:39:58 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
…		…
90		105
91	=cut	106	=cut
92		107
93	package AnyEvent::MP;	108	package AnyEvent::MP;
94		109
95	use AnyEvent::MP::Base;	110	use AnyEvent::MP::Kernel;
96		111
97	use common::sense;	112	use common::sense;
98		113
99	use Carp ();	114	use Carp ();
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::Kernel::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 initialise_node	124	resolve_node initialise_node
109	snd rcv mon kil reg psub	125	snd rcv mon kil reg psub spawn
110	port	126	port
111	);	127	);
112		128
113	our $SELF;	129	our $SELF;
114		130
…		…
123	The C<NODE> function returns, and the C<$NODE> variable contains	139	The C<NODE> function returns, and the C<$NODE> variable contains
124	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
125	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
126	identifiers become invalid.	142	identifiers become invalid.
127		143
128	=item $noderef = node_of $portid	144	=item $noderef = node_of $port
129		145
130	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";
131		211
132	=item $cv = resolve_node $noderef	212	=item $cv = resolve_node $noderef
133		213
134	Takes an unresolved node reference that may contain hostnames and	214	Takes an unresolved node reference that may contain hostnames and
135	abbreviated IDs, resolves all of them and returns a resolved node	215	abbreviated IDs, resolves all of them and returns a resolved node
…		…
167		247
168	Due to some quirks in how perl exports variables, it is impossible to	248	Due to some quirks in how perl exports variables, it is impossible to
169	just export C<$SELF>, all the symbols called C<SELF> are exported by this	249	just export C<$SELF>, all the symbols called C<SELF> are exported by this
170	module, but only C<$SELF> is currently used.	250	module, but only C<$SELF> is currently used.
171		251
172	=item snd $portid, type => @data	252	=item snd $port, type => @data
173		253
174	=item snd $portid, @msg	254	=item snd $port, @msg
175		255
176	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
177	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
178	stringifies a sa port ID (such as a port object :).	258	stringifies a sa port ID (such as a port object :).
179		259
…		…
189	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
190	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
191	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
192	node, anything can be passed.	272	node, anything can be passed.
193		273
194	=item kil $portid[, @reason]	274	=item $local_port = port
195		275
196	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.
197		279
198	If no C<@reason> is specified, then the port is killed "normally" (linked	280	=item $port = port { my @msg = @_; $finished }
199	ports will not be kileld, or even notified).
200		281
201	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
202	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.
203		285
204	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
205	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.
206		289
207	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
208	$message >>.	291	be passed to the callback.
209		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
210	=item $guard = mon $portid, $cb->(@reason)	499	=item $guard = mon $port, $cb->(@reason)
211		500
212	=item $guard = mon $portid, $otherport	501	=item $guard = mon $port, $rcvport
213		502
		503	=item $guard = mon $port
		504
214	=item $guard = mon $portid, $otherport, @msg	505	=item $guard = mon $port, $rcvport, @msg
215		506
216	Monitor the given port and do something when the port is killed.	507	Monitor the given port and do something when the port is killed or
		508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
217		510
		511	C<mon> effectively guarantees that, in the absence of hardware failures,
		512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
		518
218	In the first form, the callback is simply called with any number	519	In the first form (callback), the callback is simply called with any
219	of C<@reason> elements (no @reason means that the port was deleted	520	number of C<@reason> elements (no @reason means that the port was deleted
220	"normally"). Note also that I<< the callback B<must> never die >>, so use	521	"normally"). Note also that I<< the callback B<must> never die >>, so use
221	C<eval> if unsure.	522	C<eval> if unsure.
222		523
223	In the second form, the other port will be C<kil>'ed with C<@reason>, iff	524	In the second form (another port given), the other port (C<$rcvport>)
224	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
225	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.
226		528
		529	The third form (kill self) is the same as the second form, except that
		530	C<$rvport> defaults to C<$SELF>.
		531
227	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.
228		541
229	Example: call a given callback when C<$port> is killed.	542	Example: call a given callback when C<$port> is killed.
230		543
231	mon $port, sub { warn "port died because of <@_>\n" };	544	mon $port, sub { warn "port died because of <@_>\n" };
232		545
233	Example: kill ourselves when C<$port> is killed abnormally.	546	Example: kill ourselves when C<$port> is killed abnormally.
234		547
235	mon $port, $self;	548	mon $port;
236		549
237	Example: send us a restart message another C<$port> is killed.	550	Example: send us a restart message when another C<$port> is killed.
238		551
239	mon $port, $self => "restart";	552	mon $port, $self => "restart";
240		553
241	=cut	554	=cut
242		555
243	sub mon {	556	sub mon {
244	my ($noderef, $port) = split /#/, shift, 2;	557	my ($noderef, $port) = split /#/, shift, 2;
245		558
246	my $node = $NODE{$noderef} \|\| add_node $noderef;	559	my $node = $NODE{$noderef} \|\| add_node $noderef;
247		560
248	my $cb = shift;	561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
249		562
250	unless (ref $cb) {	563	unless (ref $cb) {
251	if (@_) {	564	if (@_) {
252	# send a kill info message	565	# send a kill info message
253	my (@msg) = ($cb, @_);	566	my (@msg) = ($cb, @_);
…		…
284	=cut	597	=cut
285		598
286	sub mon_guard {	599	sub mon_guard {
287	my ($port, @refs) = @_;	600	my ($port, @refs) = @_;
288		601
		602	#TODO: mon-less form?
		603
289	mon $port, sub { 0 && @refs }	604	mon $port, sub { 0 && @refs }
290	}	605	}
291		606
292	=item lnk $port1, $port2	607	=item kil $port[, @reason]
293		608
294	Link two ports. This is simply a shorthand for:	609	Kill the specified port with the given C<@reason>.
295		610
296	mon $port1, $port2;	611	If no C<@reason> is specified, then the port is killed "normally" (linked
297	mon $port2, $port1;	612	ports will not be kileld, or even notified).
298		613
299	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
300	killed as well.	615	C<mon>, see below).
301		616
302	=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 => $@ >>.
303		619
304	Create a new local port object that can be used either as a pattern	620	Transport/communication errors are reported as C<< transport_error =>
305	matching port ("full port") or a single-callback port ("miniport"),	621	$message >>.
306	depending on how C<rcv> callbacks are bound to the object.
307		622
308	=item $portid = port { my @msg = @_; $finished }
309
310	Creates a "mini port", that is, a very lightweight port without any
311	pattern matching behind it, and returns its ID.
312
313	The block will be called for every message received on the port. When the
314	callback returns a true value its job is considered "done" and the port
315	will be destroyed. Otherwise it will stay alive.
316
317	The message will be passed as-is, no extra argument (i.e. no port id) will
318	be passed to the callback.
319
320	If you need the local port id in the callback, this works nicely:
321
322	my $port; $port = port {
323	snd $otherport, reply => $port;
324	};
325
326	=cut	623	=cut
327		624
328	sub port(;&) {	625	=item $port = spawn $node, $initfunc[, @initdata]
329	my $id = "$UNIQ." . $ID++;
330	my $port = "$NODE#$id";
331		626
332	if (@_) {	627	Creates a port on the node C<$node> (which can also be a port ID, in which
333	my $cb = shift;	628	case it's the node where that port resides).
334	$PORT{$id} = sub {	629
335	local $SELF = $port;	630	The port ID of the newly created port is return immediately, and it is
336	eval {	631	permissible to immediately start sending messages or monitor the port.
337	&$cb	632
338	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 {
339	};	663	...
340	_self_die if $@;
341	};
342	} else {
343	my $self = bless {
344	id => "$NODE#$id",
345	}, "AnyEvent::MP::Port";
346
347	$PORT_DATA{$id} = $self;
348	$PORT{$id} = sub {
349	local $SELF = $port;
350
351	eval {
352	for (@{ $self->{rc0}{$_[0]} }) {
353	$_ && &{$_->[0]}
354	&& undef $_;
355	}
356
357	for (@{ $self->{rcv}{$_[0]} }) {
358	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
359	&& &{$_->[0]}
360	&& undef $_;
361	}
362
363	for (@{ $self->{any} }) {
364	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
365	&& &{$_->[0]}
366	&& undef $_;
367	}
368	};
369	_self_die if $@;
370	};	664	};
371	}	665	}
372		666
373	$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 $@;
374	}	678	}
375		679
376	=item reg $portid, $name	680	sub spawn(@) {
		681	my ($noderef, undef) = split /#/, shift, 2;
377		682
378	Registers the given port under the name C<$name>. If the name already	683	my $id = "$RUNIQ." . $ID++;
379	exists it is replaced.
380		684
381	A port can only be registered under one well known name.	685	$_[0] =~ /::/
		686	or Carp::croak "spawn init function must be a fully-qualified name, caught";
382		687
383	A port automatically becomes unregistered when it is killed.	688	($NODE{$noderef} \|\| add_node $noderef)
		689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
384		690
385	=cut	691	"$noderef#$id"
386
387	sub reg(@) {
388	my ($portid, $name) = @_;
389
390	$REG{$name} = $portid;
391	}	692	}
392
393	=item rcv $portid, $callback->(@msg)
394
395	Replaces the callback on the specified miniport (or newly created port
396	object, see C<port>). Full ports are configured with the following calls:
397
398	=item rcv $portid, tagstring => $callback->(@msg), ...
399
400	=item rcv $portid, $smartmatch => $callback->(@msg), ...
401
402	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
403
404	Register callbacks to be called on matching messages on the given port.
405
406	The callback has to return a true value when its work is done, after
407	which is will be removed, or a false value in which case it will stay
408	registered.
409
410	The global C<$SELF> (exported by this module) contains C<$portid> while
411	executing the callback.
412
413	Runtime errors wdurign callback execution will result in the port being
414	C<kil>ed.
415
416	If the match is an array reference, then it will be matched against the
417	first elements of the message, otherwise only the first element is being
418	matched.
419
420	Any element in the match that is specified as C<_any_> (a function
421	exported by this module) matches any single element of the message.
422
423	While not required, it is highly recommended that the first matching
424	element is a string identifying the message. The one-string-only match is
425	also the most efficient match (by far).
426
427	=cut
428
429	sub rcv($@) {
430	my $portid = shift;
431	my ($noderef, $port) = split /#/, $port, 2;
432
433	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
434	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
435
436	my $self = $PORT_DATA{$port}
437	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
438
439	"AnyEvent::MP::Port" eq ref $self
440	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
441
442	while (@_) {
443	my ($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	$portid
458	}
459
460	=item $closure = psub { BLOCK }
461
462	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
463	closure is executed, sets up the environment in the same way as in C<rcv>
464	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
465
466	This is useful when you register callbacks from C<rcv> callbacks:
467
468	rcv delayed_reply => sub {
469	my ($delay, @reply) = @_;
470	my $timer = AE::timer $delay, 0, psub {
471	snd @reply, $SELF;
472	};
473	};
474
475	=cut
476
477	sub psub(&) {
478	my $cb = shift;
479
480	my $port = $SELF
481	or Carp::croak "psub can only be called from within rcv or psub callbacks, not";
482
483	sub {
484	local $SELF = $port;
485
486	if (wantarray) {
487	my @res = eval { &$cb };
488	_self_die if $@;
489	@res
490	} else {
491	my $res = eval { &$cb };
492	_self_die if $@;
493	$res
494	}
495	}
496	}
497
498	=back
499
500	=head1 FUNCTIONS FOR NODES
501
502	=over 4
503
504	=item become_public $noderef
505
506	Tells the node to become a public node, i.e. reachable from other nodes.
507
508	The first argument is the (unresolved) node reference of the local node
509	(if missing then the empty string is used).
510
511	It is quite common to not specify anything, in which case the local node
512	tries to listen on the default port, or to only specify a port number, in
513	which case AnyEvent::MP tries to guess the local addresses.
514
515	=cut
516		693
517	=back	694	=back
518		695
519	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
520		697
…		…
562		739
563	=back	740	=back
564		741
565	=head1 AnyEvent::MP vs. Distributed Erlang	742	=head1 AnyEvent::MP vs. Distributed Erlang
566		743
567	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
568	== 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
569	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
570	sample:	747	sample:
571		748
572	http://www.erlang.se/doc/programming_rules.shtml	749	http://www.Erlang.se/doc/programming_rules.shtml
573	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
574	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
575	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
576		753
577	Despite the similarities, there are also some important differences:	754	Despite the similarities, there are also some important differences:
578		755
579	=over 4	756	=over 4
580		757
…		…
591		768
592	Erlang uses processes that selctively receive messages, and therefore	769	Erlang uses processes that selctively receive messages, and therefore
593	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
594	purpose.	771	purpose.
595		772
596	(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).
597		774
598	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
599		776
600	Sending messages in erlang is synchronous and blocks the process. AEMP	777	Sending messages in Erlang is synchronous and blocks the process. AEMP
601	sends are immediate, connection establishment is handled in the	778	sends are immediate, connection establishment is handled in the
602	background.	779	background.
603		780
604	=item * Erlang can silently lose messages, AEMP cannot.	781	=item * Erlang can silently lose messages, AEMP cannot.
605		782
…		…
608	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).
609		786
610	AEMP guarantees correct ordering, and the guarantee that there are no	787	AEMP guarantees correct ordering, and the guarantee that there are no
611	holes in the message sequence.	788	holes in the message sequence.
612		789
613	=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
614	alive.	791	alive.
615		792
616	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
617	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
618	still alive - and can receive messages.	795	still alive - and can receive messages.
619		796
620	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
621	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
622	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.
623		800
624	=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.
625		802
626	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
627	ID known to other nodes for a completely different process, causing	804	ID known to other nodes for a completely different process, causing
628	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.
629		806
630	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
631	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.
…		…
637	securely authenticate nodes.	814	securely authenticate nodes.
638		815
639	=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
640	communications.	817	communications.
641		818
642	The AEMP protocol, unlike the erlang protocol, supports both	819	The AEMP protocol, unlike the Erlang protocol, supports both
643	language-independent text-only protocols (good for debugging) and binary,	820	language-independent text-only protocols (good for debugging) and binary,
644	language-specific serialisers (e.g. Storable).	821	language-specific serialisers (e.g. Storable).
645		822
646	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
647	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
648	protocol simple.	825	protocol simple.
649		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
650	=back	849	=back
651		850
652	=head1 SEE ALSO	851	=head1 SEE ALSO
653		852
654	L<AnyEvent>.	853	L<AnyEvent>.

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Revision 1.44 by root, Wed Aug 12 21:39:58 2009 UTC