[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 1.42 by root, Sun Aug 9 00:41:49 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
…		…
104		119
105	our $VERSION = '0.1';	120	our $VERSION = '0.1';
106	our @EXPORT = qw(	121	our @EXPORT = qw(
107	NODE $NODE *SELF node_of _any_	122	NODE $NODE *SELF node_of _any_
108	resolve_node initialise_node	123	resolve_node initialise_node
109	snd rcv mon kil reg psub	124	snd rcv mon kil reg psub spawn
110	port	125	port
111	);	126	);
112		127
113	our $SELF;	128	our $SELF;
114		129
…		…
123	The C<NODE> function returns, and the C<$NODE> variable contains	138	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	139	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	140	to C<become_public> or C<become_slave>, after which all local port
126	identifiers become invalid.	141	identifiers become invalid.
127		142
128	=item $noderef = node_of $portid	143	=item $noderef = node_of $port
129		144
130	Extracts and returns the noderef from a portid or a noderef.	145	Extracts and returns the noderef from a portid or a noderef.
		146
		147	=item initialise_node $noderef, $seednode, $seednode...
		148
		149	=item initialise_node "slave/", $master, $master...
		150
		151	Before a node can talk to other nodes on the network it has to initialise
		152	itself - the minimum a node needs to know is it's own name, and optionally
		153	it should know the noderefs of some other nodes in the network.
		154
		155	This function initialises a node - it must be called exactly once (or
		156	never) before calling other AnyEvent::MP functions.
		157
		158	All arguments are noderefs, which can be either resolved or unresolved.
		159
		160	There are two types of networked nodes, public nodes and slave nodes:
		161
		162	=over 4
		163
		164	=item public nodes
		165
		166	For public nodes, C<$noderef> must either be a (possibly unresolved)
		167	noderef, in which case it will be resolved, or C<undef> (or missing), in
		168	which case the noderef will be guessed.
		169
		170	Afterwards, the node will bind itself on all endpoints and try to connect
		171	to all additional C<$seednodes> that are specified. Seednodes are optional
		172	and can be used to quickly bootstrap the node into an existing network.
		173
		174	=item slave nodes
		175
		176	When the C<$noderef> is the special string C<slave/>, then the node will
		177	become a slave node. Slave nodes cannot be contacted from outside and will
		178	route most of their traffic to the master node that they attach to.
		179
		180	At least one additional noderef is required: The node will try to connect
		181	to all of them and will become a slave attached to the first node it can
		182	successfully connect to.
		183
		184	=back
		185
		186	This function will block until all nodes have been resolved and, for slave
		187	nodes, until it has successfully established a connection to a master
		188	server.
		189
		190	Example: become a public node listening on the default node.
		191
		192	initialise_node;
		193
		194	Example: become a public node, and try to contact some well-known master
		195	servers to become part of the network.
		196
		197	initialise_node undef, "master1", "master2";
		198
		199	Example: become a public node listening on port C<4041>.
		200
		201	initialise_node 4041;
		202
		203	Example: become a public node, only visible on localhost port 4044.
		204
		205	initialise_node "locahost:4044";
		206
		207	Example: become a slave node to any of the specified master servers.
		208
		209	initialise_node "slave/", "master1", "192.168.13.17", "mp.example.net";
131		210
132	=item $cv = resolve_node $noderef	211	=item $cv = resolve_node $noderef
133		212
134	Takes an unresolved node reference that may contain hostnames and	213	Takes an unresolved node reference that may contain hostnames and
135	abbreviated IDs, resolves all of them and returns a resolved node	214	abbreviated IDs, resolves all of them and returns a resolved node
…		…
167		246
168	Due to some quirks in how perl exports variables, it is impossible to	247	Due to some quirks in how perl exports variables, it is impossible to
169	just export C<$SELF>, all the symbols called C<SELF> are exported by this	248	just export C<$SELF>, all the symbols called C<SELF> are exported by this
170	module, but only C<$SELF> is currently used.	249	module, but only C<$SELF> is currently used.
171		250
172	=item snd $portid, type => @data	251	=item snd $port, type => @data
173		252
174	=item snd $portid, @msg	253	=item snd $port, @msg
175		254
176	Send the given message to the given port ID, which can identify either	255	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	256	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 :).	257	stringifies a sa port ID (such as a port object :).
179		258
…		…
189	JSON is used, then only strings, numbers and arrays and hashes consisting	268	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	269	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	270	that Storable can serialise and deserialise is allowed, and for the local
192	node, anything can be passed.	271	node, anything can be passed.
193		272
194	=item kil $portid[, @reason]	273	=item $local_port = port
195		274
196	Kill the specified port with the given C<@reason>.	275	Create a new local port object that can be used either as a pattern
		276	matching port ("full port") or a single-callback port ("miniport"),
		277	depending on how C<rcv> callbacks are bound to the object.
197		278
198	If no C<@reason> is specified, then the port is killed "normally" (linked	279	=item $port = port { my @msg = @_; $finished }
199	ports will not be kileld, or even notified).
200		280
201	Otherwise, linked ports get killed with the same reason (second form of	281	Creates a "miniport", that is, a very lightweight port without any pattern
202	C<mon>, see below).	282	matching behind it, and returns its ID. Semantically the same as creating
		283	a port and calling C<rcv $port, $callback> on it.
203		284
204	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	285	The block will be called for every message received on the port. When the
205	will be reported as reason C<< die => $@ >>.	286	callback returns a true value its job is considered "done" and the port
		287	will be destroyed. Otherwise it will stay alive.
206		288
207	Transport/communication errors are reported as C<< transport_error =>	289	The message will be passed as-is, no extra argument (i.e. no port id) will
208	$message >>.	290	be passed to the callback.
209		291
		292	If you need the local port id in the callback, this works nicely:
		293
		294	my $port; $port = port {
		295	snd $otherport, reply => $port;
		296	};
		297
		298	=cut
		299
		300	sub rcv($@);
		301
		302	sub port(;&) {
		303	my $id = "$UNIQ." . $ID++;
		304	my $port = "$NODE#$id";
		305
		306	if (@_) {
		307	rcv $port, shift;
		308	} else {
		309	$PORT{$id} = sub { }; # nop
		310	}
		311
		312	$port
		313	}
		314
		315	=item reg $port, $name
		316
		317	=item reg $name
		318
		319	Registers the given port (or C<$SELF><<< if missing) under the name
		320	C<$name>. If the name already exists it is replaced.
		321
		322	A port can only be registered under one well known name.
		323
		324	A port automatically becomes unregistered when it is killed.
		325
		326	=cut
		327
		328	sub reg(@) {
		329	my $port = @_ > 1 ? shift : $SELF \|\| Carp::croak 'reg: called with one argument only, but $SELF not set,';
		330
		331	$REG{$_[0]} = $port;
		332	}
		333
		334	=item rcv $port, $callback->(@msg)
		335
		336	Replaces the callback on the specified miniport (after converting it to
		337	one if required).
		338
		339	=item rcv $port, tagstring => $callback->(@msg), ...
		340
		341	=item rcv $port, $smartmatch => $callback->(@msg), ...
		342
		343	=item rcv $port, [$smartmatch...] => $callback->(@msg), ...
		344
		345	Register callbacks to be called on matching messages on the given full
		346	port (after converting it to one if required) and return the port.
		347
		348	The callback has to return a true value when its work is done, after
		349	which is will be removed, or a false value in which case it will stay
		350	registered.
		351
		352	The global C<$SELF> (exported by this module) contains C<$port> while
		353	executing the callback.
		354
		355	Runtime errors during callback execution will result in the port being
		356	C<kil>ed.
		357
		358	If the match is an array reference, then it will be matched against the
		359	first elements of the message, otherwise only the first element is being
		360	matched.
		361
		362	Any element in the match that is specified as C<_any_> (a function
		363	exported by this module) matches any single element of the message.
		364
		365	While not required, it is highly recommended that the first matching
		366	element is a string identifying the message. The one-string-only match is
		367	also the most efficient match (by far).
		368
		369	Example: create a port and bind receivers on it in one go.
		370
		371	my $port = rcv port,
		372	msg1 => sub { ...; 0 },
		373	msg2 => sub { ...; 0 },
		374	;
		375
		376	Example: create a port, bind receivers and send it in a message elsewhere
		377	in one go:
		378
		379	snd $otherport, reply =>
		380	rcv port,
		381	msg1 => sub { ...; 0 },
		382	...
		383	;
		384
		385	=cut
		386
		387	sub rcv($@) {
		388	my $port = shift;
		389	my ($noderef, $portid) = split /#/, $port, 2;
		390
		391	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
		392	or Carp::croak "$port: rcv can only be called on local ports, caught";
		393
		394	if (@_ == 1) {
		395	my $cb = shift;
		396	delete $PORT_DATA{$portid};
		397	$PORT{$portid} = sub {
		398	local $SELF = $port;
		399	eval {
		400	&$cb
		401	and kil $port;
		402	};
		403	_self_die if $@;
		404	};
		405	} else {
		406	my $self = $PORT_DATA{$portid} \|\|= do {
		407	my $self = bless {
		408	id => $port,
		409	}, "AnyEvent::MP::Port";
		410
		411	$PORT{$portid} = sub {
		412	local $SELF = $port;
		413
		414	eval {
		415	for (@{ $self->{rc0}{$_[0]} }) {
		416	$_ && &{$_->[0]}
		417	&& undef $_;
		418	}
		419
		420	for (@{ $self->{rcv}{$_[0]} }) {
		421	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
		422	&& &{$_->[0]}
		423	&& undef $_;
		424	}
		425
		426	for (@{ $self->{any} }) {
		427	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
		428	&& &{$_->[0]}
		429	&& undef $_;
		430	}
		431	};
		432	_self_die if $@;
		433	};
		434
		435	$self
		436	};
		437
		438	"AnyEvent::MP::Port" eq ref $self
		439	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
		440
		441	while (@_) {
		442	my ($match, $cb) = splice @_, 0, 2;
		443
		444	if (!ref $match) {
		445	push @{ $self->{rc0}{$match} }, [$cb];
		446	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
		447	my ($type, @match) = @$match;
		448	@match
		449	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
		450	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
		451	} else {
		452	push @{ $self->{any} }, [$cb, $match];
		453	}
		454	}
		455	}
		456
		457	$port
		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
210	=item $guard = mon $portid, $cb->(@reason)	498	=item $guard = mon $port, $cb->(@reason)
211		499
212	=item $guard = mon $portid, $otherport	500	=item $guard = mon $port, $rcvport
213		501
		502	=item $guard = mon $port
		503
214	=item $guard = mon $portid, $otherport, @msg	504	=item $guard = mon $port, $rcvport, @msg
215		505
216	Monitor the given port and do something when the port is killed.	506	Monitor the given port and do something when the port is killed or
		507	messages to it were lost, and optionally return a guard that can be used
		508	to stop monitoring again.
217		509
		510	C<mon> effectively guarantees that, in the absence of hardware failures,
		511	that after starting the monitor, either all messages sent to the port
		512	will arrive, or the monitoring action will be invoked after possible
		513	message loss has been detected. No messages will be lost "in between"
		514	(after the first lost message no further messages will be received by the
		515	port). After the monitoring action was invoked, further messages might get
		516	delivered again.
		517
218	In the first form, the callback is simply called with any number	518	In the first form (callback), the callback is simply called with any
219	of C<@reason> elements (no @reason means that the port was deleted	519	number of C<@reason> elements (no @reason means that the port was deleted
220	"normally"). Note also that I<< the callback B<must> never die >>, so use	520	"normally"). Note also that I<< the callback B<must> never die >>, so use
221	C<eval> if unsure.	521	C<eval> if unsure.
222		522
223	In the second form, the other port will be C<kil>'ed with C<@reason>, iff	523	In the second form (another port given), the other port (C<$rcvport)
224	a @reason was specified, i.e. on "normal" kils nothing happens, while	524	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.	525	"normal" kils nothing happens, while under all other conditions, the other
		526	port is killed with the same reason.
226		527
		528	The third form (kill self) is the same as the second form, except that
		529	C<$rvport> defaults to C<$SELF>.
		530
227	In the last form, a message of the form C<@msg, @reason> will be C<snd>.	531	In the last form (message), a message of the form C<@msg, @reason> will be
		532	C<snd>.
		533
		534	As a rule of thumb, monitoring requests should always monitor a port from
		535	a local port (or callback). The reason is that kill messages might get
		536	lost, just like any other message. Another less obvious reason is that
		537	even monitoring requests can get lost (for exmaple, when the connection
		538	to the other node goes down permanently). When monitoring a port locally
		539	these problems do not exist.
228		540
229	Example: call a given callback when C<$port> is killed.	541	Example: call a given callback when C<$port> is killed.
230		542
231	mon $port, sub { warn "port died because of <@_>\n" };	543	mon $port, sub { warn "port died because of <@_>\n" };
232		544
233	Example: kill ourselves when C<$port> is killed abnormally.	545	Example: kill ourselves when C<$port> is killed abnormally.
234		546
235	mon $port, $self;	547	mon $port;
236		548
237	Example: send us a restart message another C<$port> is killed.	549	Example: send us a restart message when another C<$port> is killed.
238		550
239	mon $port, $self => "restart";	551	mon $port, $self => "restart";
240		552
241	=cut	553	=cut
242		554
243	sub mon {	555	sub mon {
244	my ($noderef, $port) = split /#/, shift, 2;	556	my ($noderef, $port) = split /#/, shift, 2;
245		557
246	my $node = $NODE{$noderef} \|\| add_node $noderef;	558	my $node = $NODE{$noderef} \|\| add_node $noderef;
247		559
248	my $cb = shift;	560	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
249		561
250	unless (ref $cb) {	562	unless (ref $cb) {
251	if (@_) {	563	if (@_) {
252	# send a kill info message	564	# send a kill info message
253	my (@msg) = ($cb, @_);	565	my (@msg) = ($cb, @_);
…		…
284	=cut	596	=cut
285		597
286	sub mon_guard {	598	sub mon_guard {
287	my ($port, @refs) = @_;	599	my ($port, @refs) = @_;
288		600
		601	#TODO: mon-less form?
		602
289	mon $port, sub { 0 && @refs }	603	mon $port, sub { 0 && @refs }
290	}	604	}
291		605
292	=item lnk $port1, $port2	606	=item kil $port[, @reason]
293		607
294	Link two ports. This is simply a shorthand for:	608	Kill the specified port with the given C<@reason>.
295		609
296	mon $port1, $port2;	610	If no C<@reason> is specified, then the port is killed "normally" (linked
297	mon $port2, $port1;	611	ports will not be kileld, or even notified).
298		612
299	It means that if either one is killed abnormally, the other one gets	613	Otherwise, linked ports get killed with the same reason (second form of
300	killed as well.	614	C<mon>, see below).
301		615
302	=item $local_port = port	616	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
		617	will be reported as reason C<< die => $@ >>.
303		618
304	Create a new local port object that can be used either as a pattern	619	Transport/communication errors are reported as C<< transport_error =>
305	matching port ("full port") or a single-callback port ("miniport"),	620	$message >>.
306	depending on how C<rcv> callbacks are bound to the object.
307		621
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	622	=cut
327		623
328	sub port(;&) {	624	=item $port = spawn $node, $initfunc[, @initdata]
329	my $id = "$UNIQ." . $ID++;
330	my $port = "$NODE#$id";
331		625
332	if (@_) {	626	Creates a port on the node C<$node> (which can also be a port ID, in which
333	my $cb = shift;	627	case it's the node where that port resides).
334	$PORT{$id} = sub {	628
335	local $SELF = $port;	629	The port ID of the newly created port is return immediately, and it is
336	eval {	630	permissible to immediately start sending messages or monitor the port.
337	&$cb	631
338	and kil $id;	632	After the port has been created, the init function is
		633	called. This function must be a fully-qualified function name
		634	(e.g. C<MyApp::Chat::Server::init>). To specify a function in the main
		635	program, use C<::name>.
		636
		637	If the function doesn't exist, then the node tries to C<require>
		638	the package, then the package above the package and so on (e.g.
		639	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
		640	exists or it runs out of package names.
		641
		642	The init function is then called with the newly-created port as context
		643	object (C<$SELF>) and the C<@initdata> values as arguments.
		644
		645	A common idiom is to pass your own port, monitor the spawned port, and
		646	in the init function, monitor the original port. This two-way monitoring
		647	ensures that both ports get cleaned up when there is a problem.
		648
		649	Example: spawn a chat server port on C<$othernode>.
		650
		651	# this node, executed from within a port context:
		652	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
		653	mon $server;
		654
		655	# init function on C<$othernode>
		656	sub connect {
		657	my ($srcport) = @_;
		658
		659	mon $srcport;
		660
		661	rcv $SELF, sub {
339	};	662	...
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	};	663	};
371	}	664	}
372		665
373	$port	666	=cut
		667
		668	sub _spawn {
		669	my $port = shift;
		670	my $init = shift;
		671
		672	local $SELF = "$NODE#$port";
		673	eval {
		674	&{ load_func $init }
		675	};
		676	_self_die if $@;
374	}	677	}
375		678
376	=item reg $portid, $name	679	sub spawn(@) {
		680	my ($noderef, undef) = split /#/, shift, 2;
377		681
378	Registers the given port under the name C<$name>. If the name already	682	my $id = "$RUNIQ." . $ID++;
379	exists it is replaced.
380		683
381	A port can only be registered under one well known name.	684	$_[0] =~ /::/
		685	or Carp::croak "spawn init function must be a fully-qualified name, caught";
382		686
383	A port automatically becomes unregistered when it is killed.	687	($NODE{$noderef} \|\| add_node $noderef)
		688	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
384		689
385	=cut	690	"$noderef#$id"
386
387	sub reg(@) {
388	my ($portid, $name) = @_;
389
390	$REG{$name} = $portid;
391	}	691	}
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		692
517	=back	693	=back
518		694
519	=head1 NODE MESSAGES	695	=head1 NODE MESSAGES
520		696
…		…
562		738
563	=back	739	=back
564		740
565	=head1 AnyEvent::MP vs. Distributed Erlang	741	=head1 AnyEvent::MP vs. Distributed Erlang
566		742
567	AnyEvent::MP got lots of its ideas from distributed erlang (erlang node	743	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	744	== 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	745	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
570	sample:	746	sample:
571		747
572	http://www.erlang.se/doc/programming_rules.shtml	748	http://www.Erlang.se/doc/programming_rules.shtml
573	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	749	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	750	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	751	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
576		752
577	Despite the similarities, there are also some important differences:	753	Despite the similarities, there are also some important differences:
578		754
579	=over 4	755	=over 4
580		756
…		…
591		767
592	Erlang uses processes that selctively receive messages, and therefore	768	Erlang uses processes that selctively receive messages, and therefore
593	needs a queue. AEMP is event based, queuing messages would serve no useful	769	needs a queue. AEMP is event based, queuing messages would serve no useful
594	purpose.	770	purpose.
595		771
596	(But see L<Coro::MP> for a more erlang-like process model on top of AEMP).	772	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
597		773
598	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	774	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
599		775
600	Sending messages in erlang is synchronous and blocks the process. AEMP	776	Sending messages in Erlang is synchronous and blocks the process. AEMP
601	sends are immediate, connection establishment is handled in the	777	sends are immediate, connection establishment is handled in the
602	background.	778	background.
603		779
604	=item * Erlang can silently lose messages, AEMP cannot.	780	=item * Erlang can silently lose messages, AEMP cannot.
605		781
…		…
608	and c, and the other side only receives messages a and c).	784	and c, and the other side only receives messages a and c).
609		785
610	AEMP guarantees correct ordering, and the guarantee that there are no	786	AEMP guarantees correct ordering, and the guarantee that there are no
611	holes in the message sequence.	787	holes in the message sequence.
612		788
613	=item * In erlang, processes can be declared dead and later be found to be	789	=item * In Erlang, processes can be declared dead and later be found to be
614	alive.	790	alive.
615		791
616	In erlang it can happen that a monitored process is declared dead and	792	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	793	linked processes get killed, but later it turns out that the process is
618	still alive - and can receive messages.	794	still alive - and can receive messages.
619		795
620	In AEMP, when port monitoring detects a port as dead, then that port will	796	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	797	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.	798	and then later sends messages to it, finding it is still alive.
623		799
624	=item * Erlang can send messages to the wrong port, AEMP does not.	800	=item * Erlang can send messages to the wrong port, AEMP does not.
625		801
626	In erlang it is quite possible that a node that restarts reuses a process	802	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	803	ID known to other nodes for a completely different process, causing
628	messages destined for that process to end up in an unrelated process.	804	messages destined for that process to end up in an unrelated process.
629		805
630	AEMP never reuses port IDs, so old messages or old port IDs floating	806	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.	807	around in the network will not be sent to an unrelated port.
…		…
637	securely authenticate nodes.	813	securely authenticate nodes.
638		814
639	=item * The AEMP protocol is optimised for both text-based and binary	815	=item * The AEMP protocol is optimised for both text-based and binary
640	communications.	816	communications.
641		817
642	The AEMP protocol, unlike the erlang protocol, supports both	818	The AEMP protocol, unlike the Erlang protocol, supports both
643	language-independent text-only protocols (good for debugging) and binary,	819	language-independent text-only protocols (good for debugging) and binary,
644	language-specific serialisers (e.g. Storable).	820	language-specific serialisers (e.g. Storable).
645		821
646	It has also been carefully designed to be implementable in other languages	822	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	823	with a minimum of work while gracefully degrading fucntionality to make the
648	protocol simple.	824	protocol simple.
649		825
		826	=item * AEMP has more flexible monitoring options than Erlang.
		827
		828	In Erlang, you can chose to receive I<all> exit signals as messages
		829	or I<none>, there is no in-between, so monitoring single processes is
		830	difficult to implement. Monitoring in AEMP is more flexible than in
		831	Erlang, as one can choose between automatic kill, exit message or callback
		832	on a per-process basis.
		833
		834	=item * Erlang tries to hide remote/local connections, AEMP does not.
		835
		836	Monitoring in Erlang is not an indicator of process death/crashes,
		837	as linking is (except linking is unreliable in Erlang).
		838
		839	In AEMP, you don't "look up" registered port names or send to named ports
		840	that might or might not be persistent. Instead, you normally spawn a port
		841	on the remote node. The init function monitors the you, and you monitor
		842	the remote port. Since both monitors are local to the node, they are much
		843	more reliable.
		844
		845	This also saves round-trips and avoids sending messages to the wrong port
		846	(hard to do in Erlang).
		847
650	=back	848	=back
651		849
652	=head1 SEE ALSO	850	=head1 SEE ALSO
653		851
654	L<AnyEvent>.	852	L<AnyEvent>.

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Revision 1.42 by root, Sun Aug 9 00:41:49 2009 UTC