1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
%% 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) 2007-2009 LShift
%% Ltd. Portions created by Cohesive Financial Technologies LLC are
%% Copyright (C) 2007-2009 Cohesive Financial Technologies
%% LLC. Portions created by Rabbit Technologies Ltd are Copyright
%% (C) 2007-2009 Rabbit Technologies Ltd.
%%
%% All Rights Reserved.
%%
%% Contributor(s): ______________________________________.
%%
-module(buffering_proxy).
-export([start_link/2]).
%% internal
-export([mainloop/4, drain/2]).
-export([proxy_loop/3]).
-define(HIBERNATE_AFTER, 5000).
%%----------------------------------------------------------------------------
start_link(M, A) ->
spawn_link(
fun () -> process_flag(trap_exit, true),
ProxyPid = self(),
Ref = make_ref(),
Pid = spawn_link(
fun () -> ProxyPid ! Ref,
mainloop(ProxyPid, Ref, M,
M:init(ProxyPid, A)) end),
proxy_loop(Ref, Pid, empty)
end).
%%----------------------------------------------------------------------------
mainloop(ProxyPid, Ref, M, State) ->
NewState =
receive
{Ref, Messages} ->
NewSt =
lists:foldl(fun (Msg, S) ->
drain(M, M:handle_message(Msg, S))
end, State, lists:reverse(Messages)),
ProxyPid ! Ref,
NewSt;
Msg -> M:handle_message(Msg, State)
after ?HIBERNATE_AFTER ->
erlang:hibernate(?MODULE, mainloop,
[ProxyPid, Ref, M, State])
end,
?MODULE:mainloop(ProxyPid, Ref, M, NewState).
drain(M, State) ->
receive
Msg -> ?MODULE:drain(M, M:handle_message(Msg, State))
after 0 ->
State
end.
proxy_loop(Ref, Pid, State) ->
receive
Ref ->
?MODULE:proxy_loop(
Ref, Pid,
case State of
empty -> waiting;
waiting -> exit(duplicate_next);
Messages -> Pid ! {Ref, Messages}, empty
end);
{'EXIT', Pid, Reason} ->
exit(Reason);
{'EXIT', _, Reason} ->
exit(Pid, Reason),
?MODULE:proxy_loop(Ref, Pid, State);
Msg ->
?MODULE:proxy_loop(
Ref, Pid,
case State of
empty -> [Msg];
waiting -> Pid ! {Ref, [Msg]}, empty;
Messages -> [Msg | Messages]
end)
after ?HIBERNATE_AFTER ->
erlang:hibernate(?MODULE, proxy_loop, [Ref, Pid, State])
end.
|
