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

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.36 by root, Thu Aug 6 10:46:48 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
27
28	# linking two ports, so they both crash together
29	lnk $port1, $port2;
30		37
31	# monitoring	38	# monitoring
32	mon $port, $cb->(@msg) # callback is invoked on death	39	mon $port, $cb->(@msg) # callback is invoked on death
33	mon $port, $otherport # kill otherport on abnormal death	40	mon $port, $otherport # kill otherport on abnormal death
34	mon $port, $otherport, @msg # send message on death	41	mon $port, $otherport, @msg # send message on death
…		…
108		115
109	use AE ();	116	use AE ();
110		117
111	use base "Exporter";	118	use base "Exporter";
112		119
113	our $VERSION = '0.1';	120	our $VERSION = $AnyEvent::MP::Base::VERSION;
		121
114	our @EXPORT = qw(	122	our @EXPORT = qw(
115	NODE $NODE *SELF node_of _any_	123	NODE $NODE *SELF node_of _any_
116	resolve_node initialise_node	124	resolve_node initialise_node
117	snd rcv mon kil reg psub	125	snd rcv mon kil reg psub spawn
118	port	126	port
119	);	127	);
120		128
121	our $SELF;	129	our $SELF;
122		130
…		…
343	registered.	351	registered.
344		352
345	The global C<$SELF> (exported by this module) contains C<$port> while	353	The global C<$SELF> (exported by this module) contains C<$port> while
346	executing the callback.	354	executing the callback.
347		355
348	Runtime errors wdurign callback execution will result in the port being	356	Runtime errors during callback execution will result in the port being
349	C<kil>ed.	357	C<kil>ed.
350		358
351	If the match is an array reference, then it will be matched against the	359	If the match is an array reference, then it will be matched against the
352	first elements of the message, otherwise only the first element is being	360	first elements of the message, otherwise only the first element is being
353	matched.	361	matched.
…		…
494		502
495	=item $guard = mon $port	503	=item $guard = mon $port
496		504
497	=item $guard = mon $port, $rcvport, @msg	505	=item $guard = mon $port, $rcvport, @msg
498		506
499	Monitor the given port and do something when the port is killed, and	507	Monitor the given port and do something when the port is killed or
500	optionally return a guard that can be used to stop monitoring again.	508	messages to it were lost, and optionally return a guard that can be used
		509	to stop monitoring again.
		510
		511	C<mon> effectively guarantees that, in the absence of hardware failures,
		512	that after starting the monitor, either all messages sent to the port
		513	will arrive, or the monitoring action will be invoked after possible
		514	message loss has been detected. No messages will be lost "in between"
		515	(after the first lost message no further messages will be received by the
		516	port). After the monitoring action was invoked, further messages might get
		517	delivered again.
501		518
502	In the first form (callback), the callback is simply called with any	519	In the first form (callback), the callback is simply called with any
503	number of C<@reason> elements (no @reason means that the port was deleted	520	number of C<@reason> elements (no @reason means that the port was deleted
504	"normally"). Note also that I<< the callback B<must> never die >>, so use	521	"normally"). Note also that I<< the callback B<must> never die >>, so use
505	C<eval> if unsure.	522	C<eval> if unsure.
506		523
507	In the second form (another port given), the other port (C<$rcvport)	524	In the second form (another port given), the other port (C<$rcvport>)
508	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on	525	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
509	"normal" kils nothing happens, while under all other conditions, the other	526	"normal" kils nothing happens, while under all other conditions, the other
510	port is killed with the same reason.	527	port is killed with the same reason.
511		528
512	The third form (kill self) is the same as the second form, except that	529	The third form (kill self) is the same as the second form, except that
513	C<$rvport> defaults to C<$SELF>.	530	C<$rvport> defaults to C<$SELF>.
514		531
515	In the last form (message), a message of the form C<@msg, @reason> will be	532	In the last form (message), a message of the form C<@msg, @reason> will be
516	C<snd>.	533	C<snd>.
517		534
		535	As a rule of thumb, monitoring requests should always monitor a port from
		536	a local port (or callback). The reason is that kill messages might get
		537	lost, just like any other message. Another less obvious reason is that
		538	even monitoring requests can get lost (for exmaple, when the connection
		539	to the other node goes down permanently). When monitoring a port locally
		540	these problems do not exist.
		541
518	Example: call a given callback when C<$port> is killed.	542	Example: call a given callback when C<$port> is killed.
519		543
520	mon $port, sub { warn "port died because of <@_>\n" };	544	mon $port, sub { warn "port died because of <@_>\n" };
521		545
522	Example: kill ourselves when C<$port> is killed abnormally.	546	Example: kill ourselves when C<$port> is killed abnormally.
…		…
532	sub mon {	556	sub mon {
533	my ($noderef, $port) = split /#/, shift, 2;	557	my ($noderef, $port) = split /#/, shift, 2;
534		558
535	my $node = $NODE{$noderef} \|\| add_node $noderef;	559	my $node = $NODE{$noderef} \|\| add_node $noderef;
536		560
537	my $cb = @_ ? $_[0] : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	561	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
538		562
539	unless (ref $cb) {	563	unless (ref $cb) {
540	if (@_) {	564	if (@_) {
541	# send a kill info message	565	# send a kill info message
542	my (@msg) = @_;	566	my (@msg) = ($cb, @_);
543	$cb = sub { snd @msg, @_ };	567	$cb = sub { snd @msg, @_ };
544	} else {	568	} else {
545	# simply kill other port	569	# simply kill other port
546	my $port = $cb;	570	my $port = $cb;
547	$cb = sub { kil $port, @_ if @_ };	571	$cb = sub { kil $port, @_ if @_ };
…		…
578	#TODO: mon-less form?	602	#TODO: mon-less form?
579		603
580	mon $port, sub { 0 && @refs }	604	mon $port, sub { 0 && @refs }
581	}	605	}
582		606
583	=item lnk $port1, $port2
584
585	=item lnk $otherport
586
587	Link two ports. This is simply a shorthand for:
588
589	mon $port1, $port2;
590	mon $port2, $port1;
591
592	It means that if either one is killed abnormally, the other one gets
593	killed as well.
594
595	The one-argument form assumes that one port is C<$SELF>.
596
597	=cut
598
599	sub lnk {
600	my $port1 = shift;
601	my $port2 = @_ ? shift : $SELF \|\| Carp::croak 'lnk: called with one argument only, but $SELF not set,';
602
603	mon $port1, $port2;
604	mon $port2, $port1;
605	}
606
607	=item kil $port[, @reason]	607	=item kil $port[, @reason]
608		608
609	Kill the specified port with the given C<@reason>.	609	Kill the specified port with the given C<@reason>.
610		610
611	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
…		…
617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks	617	Runtime errors while evaluating C<rcv> callbacks or inside C<psub> blocks
618	will be reported as reason C<< die => $@ >>.	618	will be reported as reason C<< die => $@ >>.
619		619
620	Transport/communication errors are reported as C<< transport_error =>	620	Transport/communication errors are reported as C<< transport_error =>
621	$message >>.	621	$message >>.
		622
		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	}
622		693
623	=back	694	=back
624		695
625	=head1 NODE MESSAGES	696	=head1 NODE MESSAGES
626		697
…		…
759	or I<none>, there is no in-between, so monitoring single processes is	830	or I<none>, there is no in-between, so monitoring single processes is
760	difficult to implement. Monitoring in AEMP is more flexible than in	831	difficult to implement. Monitoring in AEMP is more flexible than in
761	Erlang, as one can choose between automatic kill, exit message or callback	832	Erlang, as one can choose between automatic kill, exit message or callback
762	on a per-process basis.	833	on a per-process basis.
763		834
764	=item * Erlang has different semantics for monitoring and linking, AEMP has the same.	835	=item * Erlang tries to hide remote/local connections, AEMP does not.
765		836
766	Monitoring in Erlang is not an indicator of process death/crashes,	837	Monitoring in Erlang is not an indicator of process death/crashes,
767	as linking is (except linking is unreliable in Erlang). In AEMP, the	838	as linking is (except linking is unreliable in Erlang).
768	semantics of monitoring and linking are identical, linking is simply	839
769	two-way monitoring with automatic kill.	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).
770		848
771	=back	849	=back
772		850
773	=head1 SEE ALSO	851	=head1 SEE ALSO
774		852

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs. Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC

Diff Legend

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.36 by root, Thu Aug 6 10:46:48 2009 UTC vs.
Revision 1.43 by root, Sun Aug 9 16:08:16 2009 UTC