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%% The contents of this file are subject to the Mozilla Public License
%% Version 1.1 (the "License"); you may not use this file except in
%% compliance with the License. You may obtain a copy of the License at
%% http://www.mozilla.org/MPL/
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
%% License for the specific language governing rights and limitations
%% under the License.
%%
%% The Original Code is RabbitMQ.
%%
%% The Initial Developers of the Original Code are LShift Ltd,
%% Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
%%
%% Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
%% Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
%% are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
%% Technologies LLC, and Rabbit Technologies Ltd.
%%
%% Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
%% Ltd. Portions created by Cohesive Financial Technologies LLC are
%% Copyright (C) 2007-2010 Cohesive Financial Technologies
%% LLC. Portions created by Rabbit Technologies Ltd are Copyright
%% (C) 2007-2010 Rabbit Technologies Ltd.
%%
%% All Rights Reserved.
%%
%% Contributor(s): ______________________________________.
%%
-module(delegate).
-include("delegate.hrl").
-behaviour(gen_server2).
-export([start_link/1, delegate_async/2, delegate_sync/2, server/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
%%----------------------------------------------------------------------------
start_link(Hash) ->
gen_server2:start_link({local, server(Hash)},
?MODULE, [], []).
delegate_sync(Node, Thunk) when is_atom(Node) ->
gen_server2:call({server(), Node}, {thunk, Thunk}, infinity);
delegate_sync(Pid, FPid) when is_pid(Pid) ->
[[Res]] = delegate_per_node([{node(Pid), [Pid]}],
f_pid_node(fun delegate_sync/2, FPid)),
Res;
delegate_sync(Pids, FPid) when is_list(Pids) ->
lists:flatten(
delegate_per_node(split_per_node(Pids),
f_pid_node(fun delegate_sync/2, FPid))).
delegate_async(Node, Thunk) when is_atom(Node) ->
gen_server2:cast({server(), Node}, {thunk, Thunk});
delegate_async(Pid, FPid) when is_pid(Pid) ->
delegate_per_node([{node(Pid), [Pid]}],
f_pid_node(fun delegate_async/2, FPid));
delegate_async(Pids, FPid) when is_list(Pids) ->
delegate_per_node(split_per_node(Pids),
f_pid_node(fun delegate_async/2, FPid)).
%%----------------------------------------------------------------------------
split_per_node(Pids) ->
dict:to_list(
lists:foldl(
fun (Pid, D) ->
dict:update(node(Pid),
fun (Pids1) -> [Pid | Pids1] end,
[Pid], D)
end,
dict:new(), Pids)).
f_pid_node(DelegateFun, FPid) ->
fun(Pid, Node) ->
DelegateFun(Node, fun() -> FPid(Pid) end)
end.
% TODO this only gets called when we are ONLY talking to the local node - can
% we improve this?
delegate_per_node([{Node, Pids}], FPidNode) when Node == node() ->
% optimisation
[[FPidNode(Pid, node()) || Pid <- Pids]];
delegate_per_node(NodePids, FPidNode) ->
rabbit_misc:upmap(
fun ({Node, Pids}) ->
[FPidNode(Pid, Node) || Pid <- Pids]
end,
NodePids).
server() ->
server(erlang:phash(self(), ?DELEGATE_PROCESSES)).
server(Hash) ->
list_to_atom(string:concat("delegate_process_", integer_to_list(Hash))).
%%--------------------------------------------------------------------
init([]) ->
{ok, no_state}.
handle_call({thunk, Thunk}, _From, State) ->
{reply, catch Thunk(), State}.
handle_cast({thunk, Thunk}, State) ->
catch Thunk(),
{noreply, State}.
handle_info(_Info, State) ->
{noreply, State}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%%--------------------------------------------------------------------
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