MEDIUM: lua: socket: add "socket" class for TCP I/O

This patch adds the TCP I/O functionnality. The class implemented
provides the same functions than the "lua socket" project. This
make network compatibility with another LUA project. The documentation
is located here:

   http://w3.impa.br/~diego/software/luasocket/tcp.html

include/types/hlua.h

@@ -2,9 +2,14 @@
 #define _TYPES_HLUA_H
 
 #include <lua.h>
+#include <lauxlib.h>
+
+#include <types/proxy.h>
+#include <types/server.h>
 
 #define CLASS_CORE     "Core"
 #define CLASS_TXN      "TXN"
+#define CLASS_SOCKET   "Socket"
 
 struct session;
 
@@ -100,4 +105,12 @@ struct hlua_sleep {
 	unsigned int wakeup_ms; /* hour to wakeup. */
 };
 
+/* This struct is used to create coprocess doing TCP or
+ * SSL I/O. It uses a fake session.
+ */
+struct hlua_socket {
+	struct session *s; /* Session used for socket I/O. */
+	luaL_Buffer b; /* buffer used to prepare strings. */
+};
+
 #endif /* _TYPES_HLUA_H */

include/types/stream_interface.h

@@ -27,6 +27,9 @@
 
 #include <types/channel.h>
 #include <types/connection.h>
+#ifdef USE_LUA
+#include <types/hlua.h>
+#endif
 #include <types/obj_type.h>
 #include <common/config.h>
 
@@ -150,6 +153,14 @@ struct appctx {
 			struct pattern_expr *expr;
 			struct chunk chunk;
 		} map;
+#ifdef USE_LUA
+		struct {
+			int connected;
+			struct hlua_socket *socket;
+			struct list wake_on_read;
+			struct list wake_on_write;
+		} hlua;
+#endif
 	} ctx;					/* used by stats I/O handlers to dump the stats */
 };