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Diffstat (limited to 'common/server.erl')
-rw-r--r-- | common/server.erl | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/common/server.erl b/common/server.erl new file mode 100644 index 0000000..06922cc --- /dev/null +++ b/common/server.erl @@ -0,0 +1,49 @@ +%% Inspired by "Programming Erlang", +%% published by The Pragmatic Bookshelf. +%% Copyrights apply to this code. +%% We make no guarantees that this code is fit for any purpose. +%% Visit http://www.pragmaticprogrammer.com/titles/jaerlang for more book information. + +-module(server). +-export([start/2, start/3, rpc/2, swap_code/2]). + +start(Name, Mod) -> + register(Name, spawn(fun() -> loop(Name, Mod, Mod:init()) end)). + +start(Name, Mod, State) -> + register(Name, spawn(fun() -> loop(Name, Mod, State) end)). + +swap_code(Name, Mod) -> rpc(Name, {swap_code, Mod}). + +rpc(Name, Request) -> + Name ! {self(), Request}, + receive + {Name, crash} -> exit(rpc); + {Name, ok, Response} -> Response + end. + +loop(Name, Mod, OldState) -> + receive + {From, {swap_code, NewCallbackMod}} -> + From ! {Name, ok, ack}, + loop(Name, NewCallbackMod, OldState); + {From, Request} -> + {Response, NewState} = Mod:handle(From, Request, OldState), + From ! {Name, ok, Response}, + loop(Name, Mod, NewState) + %% try Mod:handle(From, Request, OldState) of + %% {Response, NewState} -> + %% From ! {Name, ok, Response}, + %% loop(Name, Mod, NewState) + %% catch + %% _: Why -> + %% log_the_error(Name, Request, Why), + %% From ! {Name, crash}, + %% loop(Name, Mod, OldState) + %% end + end. + +log_the_error(Name, Request, Why) -> + io:format("Server ~p request ~p ~n" + "caused exception ~p~n", + [Name, Request, Why]). |