Adding object table (#1)

* code for maintaining the object table

* Makefile fix

* Clone git submodules.

* directory -> object_table

* Fix Makefile and remove unnecessary files.

* Fix formatting.

* make code more generic

event_loop.h

@@ -0,0 +1,38 @@
+#ifndef EVENT_LOOP_H
+#define EVENT_LOOP_H
+
+#include <poll.h>
+#include <stdint.h>
+
+#include "utarray.h"
+
+typedef struct {
+  /* The type of connection (e.g. redis, client, manager, data transfer). */
+  int type;
+  /* Data associated with the connection (managed by the user) */
+  void *data;
+} event_loop_item;
+
+typedef struct {
+  /* Array of event_loop_items that hold information for connections. */
+  UT_array *items;
+  /* Array of file descriptors that are waiting, corresponding to items. */
+  UT_array *waiting;
+} event_loop;
+
+/* Event loop functions. */
+void event_loop_init(event_loop *loop);
+void event_loop_free(event_loop *loop);
+int64_t event_loop_attach(event_loop *loop,
+                          int type,
+                          void *data,
+                          int fd,
+                          int events);
+void event_loop_detach(event_loop *loop, int64_t index, int shall_close);
+int event_loop_poll(event_loop *loop);
+int64_t event_loop_size(event_loop *loop);
+struct pollfd *event_loop_get(event_loop *loop, int64_t index);
+void event_loop_set_data(event_loop *loop, int64_t index, void *data);
+void *event_loop_get_data(event_loop *loop, int64_t index);
+
+#endif