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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.32 by root, Wed Aug 5 19:58:46 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 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
…		…
195		275
196	Create a new local port object that can be used either as a pattern	276	Create a new local port object that can be used either as a pattern
197	matching port ("full port") or a single-callback port ("miniport"),	277	matching port ("full port") or a single-callback port ("miniport"),
198	depending on how C<rcv> callbacks are bound to the object.	278	depending on how C<rcv> callbacks are bound to the object.
199		279
200	=item $portid = port { my @msg = @_; $finished }	280	=item $port = port { my @msg = @_; $finished }
201		281
202	Creates a "mini port", that is, a very lightweight port without any	282	Creates a "miniport", that is, a very lightweight port without any pattern
203	pattern matching behind it, and returns its ID.	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	The block will be called for every message received on the port. When the	286	The block will be called for every message received on the port. When the
206	callback returns a true value its job is considered "done" and the port	287	callback returns a true value its job is considered "done" and the port
207	will be destroyed. Otherwise it will stay alive.	288	will be destroyed. Otherwise it will stay alive.
208		289
…		…
215	snd $otherport, reply => $port;	296	snd $otherport, reply => $port;
216	};	297	};
217		298
218	=cut	299	=cut
219		300
		301	sub rcv($@);
		302
220	sub port(;&) {	303	sub port(;&) {
221	my $id = "$UNIQ." . $ID++;	304	my $id = "$UNIQ." . $ID++;
222	my $port = "$NODE#$id";	305	my $port = "$NODE#$id";
223		306
224	if (@_) {	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) {
225	my $cb = shift;	396	my $cb = shift;
		397	delete $PORT_DATA{$portid};
226	$PORT{$id} = sub {	398	$PORT{$portid} = sub {
227	local $SELF = $port;	399	local $SELF = $port;
228	eval {	400	eval {
229	&$cb	401	&$cb
230	and kil $id;	402	and kil $port;
231	};	403	};
232	_self_die if $@;	404	_self_die if $@;
233	};	405	};
234	} else {	406	} else {
		407	my $self = $PORT_DATA{$portid} \|\|= do {
235	my $self = bless {	408	my $self = bless {
236	id => "$NODE#$id",	409	id => $port,
237	}, "AnyEvent::MP::Port";	410	}, "AnyEvent::MP::Port";
238		411
239	$PORT_DATA{$id} = $self;
240	$PORT{$id} = sub {	412	$PORT{$portid} = sub {
241	local $SELF = $port;	413	local $SELF = $port;
242		414
243	eval {	415	eval {
244	for (@{ $self->{rc0}{$_[0]} }) {	416	for (@{ $self->{rc0}{$_[0]} }) {
245	$_ && &{$_->[0]}	417	$_ && &{$_->[0]}
246	&& undef $_;	418	&& undef $_;
247	}	419	}
248		420
249	for (@{ $self->{rcv}{$_[0]} }) {	421	for (@{ $self->{rcv}{$_[0]} }) {
250	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]	422	$_ && [@_[1 .. @{$_->[1]}]] ~~ $_->[1]
251	&& &{$_->[0]}	423	&& &{$_->[0]}
252	&& undef $_;	424	&& undef $_;
253	}	425	}
254		426
255	for (@{ $self->{any} }) {	427	for (@{ $self->{any} }) {
256	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]	428	$_ && [@_[0 .. $#{$_->[1]}]] ~~ $_->[1]
257	&& &{$_->[0]}	429	&& &{$_->[0]}
258	&& undef $_;	430	&& undef $_;
		431	}
259	}	432	};
		433	_self_die if $@;
260	};	434	};
261	_self_die if $@;	435
		436	$self
262	};	437	};
263	}
264		438
265	$port
266	}
267
268	=item reg $portid, $name
269
270	Registers the given port under the name C<$name>. If the name already
271	exists it is replaced.
272
273	A port can only be registered under one well known name.
274
275	A port automatically becomes unregistered when it is killed.
276
277	=cut
278
279	sub reg(@) {
280	my ($portid, $name) = @_;
281
282	$REG{$name} = $portid;
283	}
284
285	=item rcv $portid, $callback->(@msg)
286
287	Replaces the callback on the specified miniport (or newly created port
288	object, see C<port>). Full ports are configured with the following calls:
289
290	=item rcv $portid, tagstring => $callback->(@msg), ...
291
292	=item rcv $portid, $smartmatch => $callback->(@msg), ...
293
294	=item rcv $portid, [$smartmatch...] => $callback->(@msg), ...
295
296	Register callbacks to be called on matching messages on the given full
297	port (or newly created port).
298
299	The callback has to return a true value when its work is done, after
300	which is will be removed, or a false value in which case it will stay
301	registered.
302
303	The global C<$SELF> (exported by this module) contains C<$portid> while
304	executing the callback.
305
306	Runtime errors wdurign callback execution will result in the port being
307	C<kil>ed.
308
309	If the match is an array reference, then it will be matched against the
310	first elements of the message, otherwise only the first element is being
311	matched.
312
313	Any element in the match that is specified as C<_any_> (a function
314	exported by this module) matches any single element of the message.
315
316	While not required, it is highly recommended that the first matching
317	element is a string identifying the message. The one-string-only match is
318	also the most efficient match (by far).
319
320	=cut
321
322	sub rcv($@) {
323	my $portid = shift;
324	my ($noderef, $port) = split /#/, $port, 2;
325
326	($NODE{$noderef} \|\| add_node $noderef) == $NODE{""}
327	or Carp::croak "$noderef#$port: rcv can only be called on local ports, caught";
328
329	my $self = $PORT_DATA{$port}
330	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";
331
332	"AnyEvent::MP::Port" eq ref $self	439	"AnyEvent::MP::Port" eq ref $self
333	or Carp::croak "$noderef#$port: rcv can only be called on message matching ports, caught";	440	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
334		441
335	while (@_) {	442	while (@_) {
336	my ($match, $cb) = splice @_, 0, 2;	443	my ($match, $cb) = splice @_, 0, 2;
337		444
338	if (!ref $match) {	445	if (!ref $match) {
339	push @{ $self->{rc0}{$match} }, [$cb];	446	push @{ $self->{rc0}{$match} }, [$cb];
340	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {	447	} elsif (("ARRAY" eq ref $match && !ref $match->[0])) {
341	my ($type, @match) = @$match;	448	my ($type, @match) = @$match;
342	@match	449	@match
343	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]	450	? push @{ $self->{rcv}{$match->[0]} }, [$cb, \@match]
344	: push @{ $self->{rc0}{$match->[0]} }, [$cb];	451	: push @{ $self->{rc0}{$match->[0]} }, [$cb];
345	} else {	452	} else {
346	push @{ $self->{any} }, [$cb, $match];	453	push @{ $self->{any} }, [$cb, $match];
		454	}
347	}	455	}
348	}	456	}
349		457
350	$portid	458	$port
351	}	459	}
352		460
353	=item $closure = psub { BLOCK }	461	=item $closure = psub { BLOCK }
354		462
355	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	463	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
…		…
386	$res	494	$res
387	}	495	}
388	}	496	}
389	}	497	}
390		498
391	=item $guard = mon $portid, $cb->(@reason)	499	=item $guard = mon $port, $cb->(@reason)
392		500
393	=item $guard = mon $portid, $otherport	501	=item $guard = mon $port, $rcvport
394		502
		503	=item $guard = mon $port
		504
395	=item $guard = mon $portid, $otherport, @msg	505	=item $guard = mon $port, $rcvport, @msg
396		506
397	Monitor the given port and do something when the port is killed.	507	Monitor the given port and do something when the port is killed or
		508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
398		510
		511	C<mon> effectively guarantees that, in the absence of hardware failures,
		512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
		518
399	In the first form, the callback is simply called with any number	519	In the first form (callback), the callback is simply called with any
400	of C<@reason> elements (no @reason means that the port was deleted	520	number of C<@reason> elements (no @reason means that the port was deleted
401	"normally"). Note also that I<< the callback B<must> never die >>, so use	521	"normally"). Note also that I<< the callback B<must> never die >>, so use
402	C<eval> if unsure.	522	C<eval> if unsure.
403		523
404	In the second form, the other port will be C<kil>'ed with C<@reason>, iff	524	In the second form (another port given), the other port (C<$rcvport>)
405	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
406	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.
407		528
		529	The third form (kill self) is the same as the second form, except that
		530	C<$rvport> defaults to C<$SELF>.
		531
408	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.
409		541
410	Example: call a given callback when C<$port> is killed.	542	Example: call a given callback when C<$port> is killed.
411		543
412	mon $port, sub { warn "port died because of <@_>\n" };	544	mon $port, sub { warn "port died because of <@_>\n" };
413		545
414	Example: kill ourselves when C<$port> is killed abnormally.	546	Example: kill ourselves when C<$port> is killed abnormally.
415		547
416	mon $port, $self;	548	mon $port;
417		549
418	Example: send us a restart message another C<$port> is killed.	550	Example: send us a restart message when another C<$port> is killed.
419		551
420	mon $port, $self => "restart";	552	mon $port, $self => "restart";
421		553
422	=cut	554	=cut
423		555
424	sub mon {	556	sub mon {
425	my ($noderef, $port) = split /#/, shift, 2;	557	my ($noderef, $port) = split /#/, shift, 2;
426		558
427	my $node = $NODE{$noderef} \|\| add_node $noderef;	559	my $node = $NODE{$noderef} \|\| add_node $noderef;
428		560
429	my $cb = shift;	561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
430		562
431	unless (ref $cb) {	563	unless (ref $cb) {
432	if (@_) {	564	if (@_) {
433	# send a kill info message	565	# send a kill info message
434	my (@msg) = ($cb, @_);	566	my (@msg) = ($cb, @_);
…		…
465	=cut	597	=cut
466		598
467	sub mon_guard {	599	sub mon_guard {
468	my ($port, @refs) = @_;	600	my ($port, @refs) = @_;
469		601
		602	#TODO: mon-less form?
		603
470	mon $port, sub { 0 && @refs }	604	mon $port, sub { 0 && @refs }
471	}	605	}
472		606
473	=item lnk $port1, $port2
474
475	Link two ports. This is simply a shorthand for:
476
477	mon $port1, $port2;
478	mon $port2, $port1;
479
480	It means that if either one is killed abnormally, the other one gets
481	killed as well.
482
483	=item kil $portid[, @reason]	607	=item kil $port[, @reason]
484		608
485	Kill the specified port with the given C<@reason>.	609	Kill the specified port with the given C<@reason>.
486		610
487	If no C<@reason> is specified, then the port is killed "normally" (linked	611	If no C<@reason> is specified, then the port is killed "normally" (linked
488	ports will not be kileld, or even notified).	612	ports will not be kileld, or even notified).
…		…
494	will be reported as reason C<< die => $@ >>.	618	will be reported as reason C<< die => $@ >>.
495		619
496	Transport/communication errors are reported as C<< transport_error =>	620	Transport/communication errors are reported as C<< transport_error =>
497	$message >>.	621	$message >>.
498		622
499	=back
500
501	=head1 FUNCTIONS FOR NODES
502
503	=over 4
504
505	=item become_public $noderef
506
507	Tells the node to become a public node, i.e. reachable from other nodes.
508
509	The first argument is the (unresolved) node reference of the local node
510	(if missing then the empty string is used).
511
512	It is quite common to not specify anything, in which case the local node
513	tries to listen on the default port, or to only specify a port number, in
514	which case AnyEvent::MP tries to guess the local addresses.
515
516	=cut	623	=cut
		624
		625	=item $port = spawn $node, $initfunc[, @initdata]
		626
		627	Creates a port on the node C<$node> (which can also be a port ID, in which
		628	case it's the node where that port resides).
		629
		630	The port ID of the newly created port is return immediately, and it is
		631	permissible to immediately start sending messages or monitor the port.
		632
		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 {
		663	...
		664	};
		665	}
		666
		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 $@;
		678	}
		679
		680	sub spawn(@) {
		681	my ($noderef, undef) = split /#/, shift, 2;
		682
		683	my $id = "$RUNIQ." . $ID++;
		684
		685	$_[0] =~ /::/
		686	or Carp::croak "spawn init function must be a fully-qualified name, caught";
		687
		688	($NODE{$noderef} \|\| add_node $noderef)
		689	->send (["", "AnyEvent::MP::_spawn" => $id, @_]);
		690
		691	"$noderef#$id"
		692	}
517		693
518	=back	694	=back
519		695
520	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
521		697
…		…
563		739
564	=back	740	=back
565		741
566	=head1 AnyEvent::MP vs. Distributed Erlang	742	=head1 AnyEvent::MP vs. Distributed Erlang
567		743
568	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
569	== 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
570	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
571	sample:	747	sample:
572		748
573	http://www.erlang.se/doc/programming_rules.shtml	749	http://www.Erlang.se/doc/programming_rules.shtml
574	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
575	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
576	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
577		753
578	Despite the similarities, there are also some important differences:	754	Despite the similarities, there are also some important differences:
579		755
580	=over 4	756	=over 4
581		757
…		…
592		768
593	Erlang uses processes that selctively receive messages, and therefore	769	Erlang uses processes that selctively receive messages, and therefore
594	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
595	purpose.	771	purpose.
596		772
597	(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).
598		774
599	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	775	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
600		776
601	Sending messages in erlang is synchronous and blocks the process. AEMP	777	Sending messages in Erlang is synchronous and blocks the process. AEMP
602	sends are immediate, connection establishment is handled in the	778	sends are immediate, connection establishment is handled in the
603	background.	779	background.
604		780
605	=item * Erlang can silently lose messages, AEMP cannot.	781	=item * Erlang can silently lose messages, AEMP cannot.
606		782
…		…
609	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).
610		786
611	AEMP guarantees correct ordering, and the guarantee that there are no	787	AEMP guarantees correct ordering, and the guarantee that there are no
612	holes in the message sequence.	788	holes in the message sequence.
613		789
614	=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
615	alive.	791	alive.
616		792
617	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
618	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
619	still alive - and can receive messages.	795	still alive - and can receive messages.
620		796
621	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
622	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
623	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.
624		800
625	=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.
626		802
627	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
628	ID known to other nodes for a completely different process, causing	804	ID known to other nodes for a completely different process, causing
629	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.
630		806
631	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
632	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.
…		…
638	securely authenticate nodes.	814	securely authenticate nodes.
639		815
640	=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
641	communications.	817	communications.
642		818
643	The AEMP protocol, unlike the erlang protocol, supports both	819	The AEMP protocol, unlike the Erlang protocol, supports both
644	language-independent text-only protocols (good for debugging) and binary,	820	language-independent text-only protocols (good for debugging) and binary,
645	language-specific serialisers (e.g. Storable).	821	language-specific serialisers (e.g. Storable).
646		822
647	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
648	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
649	protocol simple.	825	protocol simple.
650		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
651	=back	849	=back
652		850
653	=head1 SEE ALSO	851	=head1 SEE ALSO
654		852
655	L<AnyEvent>.	853	L<AnyEvent>.

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