[MOD/TESTING] Begin storing the state at each event

This probably needs some cache evicting to avoid piling up large
states.

src/Room.c

@@ -437,26 +437,69 @@ RoomStateGet(Room * room)
     
     /* TODO: Consider caching the deserialised result, as doing that on a 
      * large state would probably eat up a lot of time! */
+    
+    /* TODO: Update the cached state */
     database_state = DbJson(room->state_ref);
     return StateDeserialise(database_state);
 }
 HashMap *
-RoomStateGetID(Room * room, char *event_id)
+RoomStateGetID(Room * room, char *event_id, HashMap *e)
 {
     HashMap *event, *state;
-    if (!room || !event_id)
+    if (!room)
     {
         return NULL;
     }
-
-    event = RoomEventFetch(room, event_id);
-    if (!event)
+    if (!e && !event_id)
     {
         return NULL;
     }
+    if (!event_id)
+    {
+        event_id = JsonValueAsString(HashMapGet(e, "event_id"));
+    }
+
+    if (DbExists(room->db, 4, "rooms", room->id, "state", event_id))
+    {
+        DbRef *ref = DbLock(room->db, 4, 
+            "rooms", room->id, "state", event_id
+        );
+        state = StateDeserialise(DbJson(ref));
+        DbUnlock(room->db, ref);
+        if (state)
+        {
+            return state;
+        }
+        
+        /* If a DB error stops us from getting an existing state, 
+         * recompute it. */
+    }
+
+    event = e;
+    if (!event)
+    {
+        event = RoomEventFetch(room, event_id);
+        if (!event)
+        {
+            return NULL;
+        }
+    }
 
     state = StateResolve(room, event);
-    JsonFree(event);
+    if (state)
+    {
+        HashMap *json = StateSerialise(state);
+        char *id = room->id;
+        DbRef *ref = DbCreate(room->db, 4, "rooms", id, "state", event_id);
+        DbJsonSet(ref, json);
+        JsonFree(json);
+        DbUnlock(room->db, ref);
+        
+    }
+    if (!e)
+    {
+        JsonFree(event);
+    }
 
     return state;
 }
@@ -1555,8 +1598,7 @@ RoomEventSendV1(Room * room, HashMap * event)
     client_event = !PopulateEventV1(room, event, &pdu, RoomGetCreator(room));
     pdu_object = PduV1ToJson(&pdu);
 
-    state = StateResolve(room, pdu_object); /* Compute the state 
-                                             * at that point for later. */
+    state = RoomStateGetID(room, NULL, pdu_object);
     if (client_event)
     {
         char *ev_id;

src/State.c

@@ -408,3 +408,23 @@ StateDeserialise(HashMap *json_state)
 
     return raw_state;
 }
+HashMap *
+StateSerialise(HashMap *rawState)
+{
+    HashMap *returned;
+    char *type, *key, *event;
+    if (!rawState)
+    {
+        return NULL;
+    }
+
+    returned = HashMapCreate();
+    while (StateIterate(rawState, &type, &key, (void **) &event))
+    {
+        JsonSet(returned, JsonValueString(event), 2, type, key);
+        Free(type);
+        Free(key);
+    }
+
+    return returned;
+}

src/include/Room.h

@@ -102,10 +102,11 @@ extern int RoomVersionGet(Room *);
 extern HashMap * RoomStateGet(Room *);
 /** 
  * Resolves the room's state before a specific point, 
+ * (with the event hashmap taking priority),
  * like
  * .Fn RoomStateGet .
  */
-extern HashMap * RoomStateGetID(Room *, char *);
+extern HashMap * RoomStateGetID(Room *, char *, HashMap *);
 
 /**
  * Get a list of the most recent events in the