Add 'apps/rexi/' from commit '85ae6ca690edad17ceb92b856623a0a599924c77'

git-subtree-dir: apps/rexi
git-subtree-mainline: 4b47d4c5f39a1998c07af07cf7e6b2163ce1eae5
git-subtree-split: 85ae6ca690edad17ceb92b856623a0a599924c77

1 files changed, 86 insertions, 0 deletions

diff --git a/apps/rexi/src/rexi_server.erl b/apps/rexi/src/rexi_server.erl
new file mode 100644
index 00000000..c4dc740d
--- /dev/null
+++ b/apps/rexi/src/rexi_server.erl
@@ -0,0 +1,86 @@
+-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 = ets:new(workers, [private, {keypos,2}])
+}).
+
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+init([]) ->
+    {ok, #st{}}.
+
+handle_call(_Request, _From, St) ->
+    {reply, ignored, 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_cast({kill, FromRef}, #st{workers=Workers} = St) ->
+    case find_worker_from(FromRef, Workers) of
+    {Pid, KeyRef, {_, FromRef}} ->
+        erlang:demonitor(KeyRef),
+        exit(Pid, kill),
+        {noreply, St#st{workers = remove_worker(KeyRef, Workers)}};
+    false ->
+        {noreply, St}
+    end.
+
+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, Reason),
+        {noreply, St#st{workers = remove_worker(Ref, Workers)}};
+    false ->
+        {noreply, St}
+    end;
+
+handle_info(_Info, St) ->
+    {noreply, St}.
+
+terminate(_Reason, St) ->
+    ets:foldl(fun({Pid, _, _}, _) -> exit(Pid,kill) end, nil, St#st.workers),
+    ok.
+
+code_change(_OldVsn, St, _Extra) ->
+    {ok, St}.
+
+%% @doc initializes a process started by rexi_server.
+-spec init_p({pid(), reference()}, {atom(), atom(), list()}) -> any().
+init_p(From, {M,F,A}) ->
+    put(rexi_from, From),
+    put(initial_call, {M,F,length(A)}),
+    try apply(M, F, A) catch _:Reason -> exit(Reason) end.
+
+%% internal
+
+add_worker(Worker, Tab) ->
+    ets:insert(Tab, Worker), Tab.
+
+remove_worker(Ref, Tab) ->
+    ets:delete(Tab, Ref), Tab.
+
+find_worker(Ref, Tab) ->
+    case ets:lookup(Tab, Ref) of [] -> false; [Worker] -> Worker end.
+
+find_worker_from(Ref, Tab) ->
+    case ets:match_object(Tab, {'_', '_', {'_', Ref}}) of
+    [] ->
+        false;
+    [Worker] ->
+        Worker
+    end.
+
+notify_caller({Caller, Ref}, Reason) ->
+    Caller ! {Ref, {rexi_EXIT, Reason}}.