From e4bdc05bc816f4b314544f0a8a0baea9631e4cf4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonatan=20P=C3=A5lsson?= <jonte@jonte-ThinkPad-T410.(none)>
Date: Wed, 16 Feb 2011 16:05:48 +0100
Subject: [PATCH] Added documentation for ggs_gamevm.erl

---
 src/ggs_gamevm.erl | 50 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/src/ggs_gamevm.erl b/src/ggs_gamevm.erl
index e69de29..8116a96 100644
--- a/src/ggs_gamevm.erl
+++ b/src/ggs_gamevm.erl
@@ -0,0 +1,50 @@
+-module(ggs_vm_runner).
+-export([start_link/0, define/2, user_command/4]).
+%% @doc This module is responsible for running the game VM:s. You can issue
+%% commands to a vm using this module.
+
+%% @doc Create a new VM process. The process ID is returned and can be used
+%% with for example the define method of this module.
+start_link() ->  
+    erlang_js:start(), %% @TODO: should only be done once
+    PortPid = spawn_link(   fun() ->
+                                process_flag(trap_exit, true),
+                                {ok, Port} = js_driver:new(),
+                                js:define(Port, <<"function userCommand(user, command, args){return 'Hello world';}">>),  
+                                loop(Port)
+                            end ),
+    PortPid. 
+
+%% @doc Define some new code on the specified VM, returns the atom ok.
+define(GameVM, SourceCode) ->
+    GameVM ! {define,SourceCode},
+    ok.
+
+%% @doc Execute a user command on the specified VM. This function is
+%% asynchronous, and returns ok.
+%% @spec user_command(GameVM, User, Command, Args) -> ok
+%%      GameVM  = process IS of VM
+%%      Player  = the player running the command
+%%      Command = a game command to run
+%%      Args    = arguments for the Command parameter
+user_command(GameVM, Player, Command, Args) ->
+    Ref = make_ref(),
+    GameVM ! {user_command, Player, Command, Args, self(), Ref},
+    ok.
+
+%% Helper functions
+
+loop(Port) ->
+    receive
+        {define, SourceCode} ->
+            ok = js:define(Port, list_to_binary(SourceCode)),
+            loop(Port); 
+        {user_command, User, Command, Args, From, Ref} -> 
+            {ok, Ret} = js:call(Port, <<"userCommand">>, 
+                                    [   list_to_binary(User),
+                                        list_to_binary(Command),
+                                        list_to_binary(Args)
+                                    ]),
+            From ! {Ref, Ret},
+            loop(Port)
+    end.