1 files changed, 91 insertions, 0 deletions
diff --git a/apps/rexi/src/rexi.erl b/apps/rexi/src/rexi.erl
new file mode 100644
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+++ b/apps/rexi/src/rexi.erl
@@ -0,0 +1,91 @@
+-module(rexi).
+-export([start/0, stop/0, restart/0]).
+-export([cast/2, cast/3, kill/2]).
+-export([reply/1, sync_reply/1, sync_reply/2]).
+-export([async_server_call/2, async_server_call/3]).
+
+-define(SERVER, rexi_server).
+
+start() ->
+    application:start(rexi).
+
+stop() ->
+    application:stop(rexi).
+
+restart() ->
+    stop(), start().
+
+%% @equiv cast(Node, self(), MFA)
+-spec cast(node(), {atom(), atom(), list()}) -> reference().
+cast(Node, MFA) ->
+    cast(Node, self(), MFA).
+
+%% @doc Executes apply(M, F, A) on Node.
+%% You might want to use this instead of rpc:cast/4 for two reasons.  First,
+%% the Caller pid and the returned reference are inserted into the remote
+%% process' dictionary as `rexi_from', so it has a way to communicate with you.
+%% Second, the remote process is monitored. If it exits with a Reason other
+%% than normal, Caller will receive a message of the form
+%% `{Ref, {rexi_EXIT, Reason}}' where Ref is the returned reference.
+-spec cast(node(), pid(), {atom(), atom(), list()}) -> reference().
+cast(Node, Caller, MFA) ->
+    Ref = make_ref(),
+    ok = gen_server:cast({?SERVER, Node}, {doit, {Caller,Ref}, MFA}),
+    Ref.
+
+%% @doc Sends an async kill signal to the remote process associated with Ref.
+%% No rexi_EXIT message will be sent.
+-spec kill(node(), reference()) -> ok.
+kill(Node, Ref) ->
+    ok = gen_server:cast({?SERVER, Node}, {kill, Ref}).
+
+%% @equiv async_server_call(Server, self(), Request)
+-spec async_server_call(pid() | {atom(),node()}, any()) -> reference().
+async_server_call(Server, Request) ->
+    async_server_call(Server, self(), Request).
+
+%% @doc Sends a properly formatted gen_server:call Request to the Server and
+%% returns the reference which the Server will include in its reply.  The
+%% function acts more like cast() than call() in that the server process
+%% is not monitored.  Clients who want to know if the server is alive should
+%% monitor it themselves before calling this function.
+-spec async_server_call(pid() | {atom(),node()}, pid(), any()) -> reference().
+async_server_call(Server, Caller, Request) ->
+    Ref = make_ref(),
+    do_send(Server, {'$gen_call', {Caller,Ref}, Request}),
+    Ref.
+
+%% @doc convenience function to reply to the original rexi Caller.
+-spec reply(any()) -> any().
+reply(Reply) ->
+    {Caller, Ref} = get(rexi_from),
+    erlang:send(Caller, {Ref,Reply}).
+
+%% @equiv sync_reply(Reply, 300000)
+sync_reply(Reply) ->
+    sync_reply(Reply, 300000).
+
+%% @doc convenience function to reply to caller and wait for response.  Message
+%% is of the form {OriginalRef, {self(),reference()}, Reply}, which enables the
+%% original caller to respond back.
+-spec sync_reply(any(), pos_integer() | infinity) -> any().
+sync_reply(Reply, Timeout) ->
+    {Caller, Ref} = get(rexi_from),
+    Tag = make_ref(),
+    erlang:send(Caller, {Ref, {self(),Tag}, Reply}),
+    receive {Tag, Response} ->
+        Response
+    after Timeout ->
+        timeout
+    end.
+
+%% internal functions %%
+
+% send a message as quickly as possible
+do_send(Dest, Msg) ->
+    case erlang:send(Dest, Msg, [noconnect]) of
+    noconnect ->
+        spawn(erlang, send, [Dest, Msg]);
+    ok ->
+        ok
+    end.