Core: Add new system for parallelizing client packet processing. Handle WorldSession updates in Map::Update() where we are safe to proceed. Patch by Ambal.

(And clean up tabs and whitespace while rummaging around in there)
Closes issue 5084.

--HG--
branch : trunk

src/server/game/Server/WorldSession.h

@@ -138,6 +138,43 @@ enum CharterTypes
     ARENA_TEAM_CHARTER_5v5_TYPE                   = 5
 };
 
+//class to deal with packet processing
+//allows to determine if next packet is safe to be processed
+class PacketFilter
+{
+public:
+    explicit PacketFilter(WorldSession * pSession) : m_pSession(pSession) {}
+    virtual ~PacketFilter() {}
+
+    virtual bool Process(WorldPacket * packet) { return true; }
+    virtual bool ProcessLogout() const { return true; }
+
+protected:
+    WorldSession * const m_pSession;
+};
+//process only thread-safe packets in Map::Update()
+class MapSessionFilter : public PacketFilter
+{
+public:
+    explicit MapSessionFilter(WorldSession * pSession) : PacketFilter(pSession) {}
+    ~MapSessionFilter() {}
+
+    virtual bool Process(WorldPacket * packet);
+    //in Map::Update() we do not process player logout!
+    virtual bool ProcessLogout() const { return false; }
+};
+
+//class used to filer only thread-unsafe packets from queue
+//in order to update only be used in World::UpdateSessions()
+class WorldSessionFilter : public PacketFilter
+{
+public:
+    explicit WorldSessionFilter(WorldSession * pSession) : PacketFilter(pSession) {}
+    ~WorldSessionFilter() {}
+
+    virtual bool Process(WorldPacket* packet);
+};
+
 /// Player session in the World
 class WorldSession
 {
@@ -201,7 +238,7 @@ class WorldSession
         void KickPlayer();
 
         void QueuePacket(WorldPacket* new_packet);
-        bool Update(uint32 diff);
+        bool Update(uint32 diff, PacketFilter& updater);
 
         /// Handle the authentication waiting queue (to be completed)
         void SendAuthWaitQue(uint32 position);