| -module(rexi_server). |
| -behaviour(gen_server). |
| -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, |
| code_change/3]). |
| |
| -export([start_link/0, init_p/2]). |
| |
| -include_lib("eunit/include/eunit.hrl"). |
| |
| -record(st, { |
| workers = [] |
| }). |
| |
| start_link() -> |
| gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). |
| |
| init([]) -> |
| {ok, #st{}}. |
| |
| handle_call(_Request, _From, St) -> |
| {reply, ok, St}. |
| |
| handle_cast({doit, From, MFA}, #st{workers=Workers} = St) -> |
| {LocalPid, Ref} = spawn_monitor(?MODULE, init_p, [From, MFA]), |
| {noreply, St#st{workers = add_worker({LocalPid, Ref, From}, Workers)}}. |
| |
| handle_info({'DOWN', Ref, process, _, normal}, #st{workers=Workers} = St) -> |
| {noreply, St#st{workers = remove_worker(Ref, Workers)}}; |
| |
| handle_info({'DOWN', Ref, process, Pid, Reason}, #st{workers=Workers} = St) -> |
| case find_worker(Ref, Workers) of |
| {Pid, Ref, From} -> |
| notify_caller(From, Pid, Reason); |
| false -> ok end, |
| {noreply, St#st{workers = remove_worker(Ref, Workers)}}; |
| |
| handle_info(_Info, St) -> |
| {noreply, St}. |
| |
| terminate(_Reason, St) -> |
| [exit(Pid,kill) || {Pid, _, _} <- St#st.workers], |
| ok. |
| |
| code_change(_OldVsn, St, _Extra) -> |
| {ok, St}. |
| |
| init_p(From, {M,F,A}) -> |
| put(rexi_from, From), |
| try apply(M, F, A) catch _:Reason -> exit(Reason) end. |
| |
| %% internal |
| |
| add_worker(Worker, List) -> |
| [Worker | List]. |
| |
| remove_worker(Ref, List) -> |
| lists:keydelete(Ref, 2, List). |
| |
| find_worker(Ref, List) -> |
| lists:keyfind(Ref, 2, List). |
| |
| notify_caller({Caller, CallerRef}, Pid, Reason) -> |
| Caller ! {worker_died, CallerRef, Pid, Reason}. |