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authorUlf Wiger <ulf.wiger@erlang-solutions.com>2011-01-17 15:47:00 +0100
committerHenrik Nord <henrik@erlang.org>2011-11-24 09:36:13 +0100
commitb0426732cc19598f0c0c310b1e79918252495259 (patch)
tree1df6738bed330f1db2f5cde963d153978b867378 /lib/stdlib/src/gen_server.erl
parentf545894e96d5898285eee8dce812c885cf208fb7 (diff)
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Add plugin support for alternative name lookup
OTP behaviour instances (gen_server, gen_fsm, gen_event) can currently register themselves either locally or globally, and the behaviour libraries (including gen.erl) support both addressing methods, as well as the normal Pid and {Name, Node}. However, there are alternative registry implementations - e.g. gproc - and one can well imagine other ways of locating a behaviour instance, e.g. on a node connected only via a TCP tunnel, rather than via Distributed Erlang. In all these cases, one needs to write extra code to identify the behaviour instance, even though the instance itself need not be aware of how it is located. This patch introduces a new way of locating a behaviour instance: {via, Module, Name}. Module is expected to export a subset of the functions in global.erl, namely: register_name(Name, Pid) -> yes | no whereis_name(Name) -> pid() | undefined unregister_name(Name) -> ok send(Name, Msg) -> Pid Semantics are expected to be the same as for global.erl This can be used in all places where {global, Name} is accepted. faulty export in gen_fsm_SUITE.erl await process death in dummy_via:reset() fix error in gen_[server|fsm]:enter_loop() fix documentation
Diffstat (limited to 'lib/stdlib/src/gen_server.erl')
-rw-r--r--lib/stdlib/src/gen_server.erl23
1 files changed, 21 insertions, 2 deletions
diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl
index 6f075bbe5a..244795df9f 100644
--- a/lib/stdlib/src/gen_server.erl
+++ b/lib/stdlib/src/gen_server.erl
@@ -142,7 +142,7 @@
%%% start(Name, Mod, Args, Options)
%%% start_link(Mod, Args, Options)
%%% start_link(Name, Mod, Args, Options) where:
-%%% Name ::= {local, atom()} | {global, atom()}
+%%% Name ::= {local, atom()} | {global, atom()} | {via, atom(), term()}
%%% Mod ::= atom(), callback module implementing the 'real' server
%%% Args ::= term(), init arguments (to Mod:init/1)
%%% Options ::= [{timeout, Timeout} | {debug, [Flag]}]
@@ -194,6 +194,9 @@ call(Name, Request, Timeout) ->
cast({global,Name}, Request) ->
catch global:send(Name, cast_msg(Request)),
ok;
+cast({via, Mod, Name}, Request) ->
+ catch Mod:send(Name, cast_msg(Request)),
+ ok;
cast({Name,Node}=Dest, Request) when is_atom(Name), is_atom(Node) ->
do_cast(Dest, Request);
cast(Dest, Request) when is_atom(Dest) ->
@@ -266,7 +269,11 @@ multi_call(Nodes, Name, Req, Timeout)
enter_loop(Mod, Options, State) ->
enter_loop(Mod, Options, State, self(), infinity).
-enter_loop(Mod, Options, State, ServerName = {_, _}) ->
+enter_loop(Mod, Options, State, ServerName = {Scope, _})
+ when Scope == local; Scope == local ->
+ enter_loop(Mod, Options, State, ServerName, infinity);
+
+enter_loop(Mod, Options, State, ServerName = {via, _, _}) ->
enter_loop(Mod, Options, State, ServerName, infinity);
enter_loop(Mod, Options, State, Timeout) ->
@@ -327,12 +334,15 @@ init_it(Starter, Parent, Name0, Mod, Args, Options) ->
name({local,Name}) -> Name;
name({global,Name}) -> Name;
+name({via,_, Name}) -> Name;
name(Pid) when is_pid(Pid) -> Pid.
unregister_name({local,Name}) ->
_ = (catch unregister(Name));
unregister_name({global,Name}) ->
_ = global:unregister_name(Name);
+unregister_name({via, Mod, Name}) ->
+ _ = Mod:unregister_name(Name);
unregister_name(Pid) when is_pid(Pid) ->
Pid.
@@ -827,6 +837,15 @@ get_proc_name({global, Name}) ->
Name;
_Pid ->
exit(process_not_registered_globally)
+ end;
+get_proc_name({via, Mod, Name}) ->
+ case Mod:whereis_name(Name) of
+ undefined ->
+ exit({process_not_registered_via, Mod});
+ Pid when Pid =:= self() ->
+ Name;
+ _Pid ->
+ exit({process_not_registered_via, Mod})
end.
get_parent() ->