8 files changed, 94 insertions, 3 deletions

diff --git a/src/ClientHandle.cpp b/src/ClientHandle.cpp
index c4a620565..cc83bcab3 100644
--- a/src/ClientHandle.cpp
+++ b/src/ClientHandle.cpp
@@ -1778,6 +1778,43 @@ void cClientHandle::HandleKeepAlive(int a_KeepAliveID)
 
 
 
+bool cClientHandle::CheckMultiLogin(const AString & a_Username)
+{
+	// If the multilogin is allowed, skip this check entirely:
+	if ((cRoot::Get()->GetServer()->DoesAllowMultiLogin()))
+	{
+		return true;
+	}
+	
+	// Check if the player is waiting to be transferred to the World.
+	if (cRoot::Get()->GetServer()->IsPlayerInQueue(a_Username))
+	{
+		Kick("A player of the username is already logged in");
+		return false;
+	}
+
+	class cCallback :
+		public cPlayerListCallback
+	{
+		virtual bool Item(cPlayer * a_Player) override
+		{
+			return true;
+		}
+	} Callback;	
+
+	// Check if the player is in any World.
+	if (cRoot::Get()->DoWithPlayer(a_Username, Callback))
+	{
+		Kick("A player of the username is already logged in");
+		return false;
+	}
+	return true;
+}
+
+
+
+
+
 bool cClientHandle::HandleHandshake(const AString & a_Username)
 {
 	if (!cRoot::Get()->GetPluginManager()->CallHookHandshake(*this, a_Username))
@@ -1788,7 +1825,8 @@ bool cClientHandle::HandleHandshake(const AString & a_Username)
 			return false;
 		}
 	}
-	return true;
+
+	return CheckMultiLogin(a_Username);
 }
 
 
diff --git a/src/ClientHandle.h b/src/ClientHandle.h
index 495348ac3..0e588d839 100644
--- a/src/ClientHandle.h
+++ b/src/ClientHandle.h
@@ -280,6 +280,10 @@ public:
 	void HandleEntityLeaveBed         (int a_EntityID);
 	void HandleEntitySprinting        (int a_EntityID, bool a_IsSprinting);
 	
+	/** Kicks the current player if the same username is already logged in. 
+	Returns false if a player has been kicked, true otherwise. */
+	bool CheckMultiLogin(const AString & a_Username);
+	
 	/** Called when the protocol handshake has been received (for protocol versions that support it;
 	otherwise the first instant when a username is received).
 	Returns true if the player is to be let in, false if they were disconnected
diff --git a/src/Root.cpp b/src/Root.cpp
index a396d6998..29daaedcc 100644
--- a/src/Root.cpp
+++ b/src/Root.cpp
@@ -643,6 +643,22 @@ bool cRoot::DoWithPlayerByUUID(const AString & a_PlayerUUID, cPlayerListCallback
 
 
 
+bool cRoot::DoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback)
+{
+	for (auto World : m_WorldsByName)
+	{
+		if (World.second->DoWithPlayer(a_PlayerName, a_Callback))
+		{
+			return true;
+		}
+	}
+	return false;
+}
+
+
+
+
+
 AString cRoot::GetProtocolVersionTextFromInt(int a_ProtocolVersion)
 {
 	return cProtocolRecognizer::GetVersionTextFromInt(a_ProtocolVersion);
diff --git a/src/Root.h b/src/Root.h
index e70b284f9..2c512a5df 100644
--- a/src/Root.h
+++ b/src/Root.h
@@ -129,7 +129,10 @@ public:
 
 	/** Finds the player over his uuid and calls the callback */
 	bool DoWithPlayerByUUID(const AString & a_PlayerUUID, cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
-
+	
+	/** Finds the player using it's complete username and calls the callback */
+	bool DoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback);
+	
 	// tolua_begin
 	
 	/// Sends a chat message to all connected clients (in all worlds)
diff --git a/src/Server.cpp b/src/Server.cpp
index d6163df7e..3eaf6e096 100644
--- a/src/Server.cpp
+++ b/src/Server.cpp
@@ -196,6 +196,7 @@ bool cServer::InitServer(cIniFile & a_SettingsIni, bool a_ShouldAuth)
 	m_Description = a_SettingsIni.GetValueSet("Server", "Description", "MCServer - in C++!");
 	m_MaxPlayers  = a_SettingsIni.GetValueSetI("Server", "MaxPlayers", 100);
 	m_bIsHardcore = a_SettingsIni.GetValueSetB("Server", "HardcoreEnabled", false);
+	m_bAllowMultiLogin = a_SettingsIni.GetValueSetB("Server", "AllowMultiLogin", false);
 	m_PlayerCount = 0;
 	m_PlayerCountDiff = 0;
 
@@ -298,6 +299,23 @@ int cServer::GetNumPlayers(void) const
 
 
 
+bool cServer::IsPlayerInQueue(AString a_Username)
+{
+	cCSLock Lock(m_CSClients);
+	for (auto client : m_Clients)
+	{
+		if ((client->GetUsername()).compare(a_Username) == 0)
+		{
+			return true;
+		}
+	}
+	return false;
+}
+
+
+
+
+
 void cServer::PrepareKeys(void)
 {
 	LOGD("Generating protocol encryption keypair...");
diff --git a/src/Server.h b/src/Server.h
index 022794bbc..39a5a1a71 100644
--- a/src/Server.h
+++ b/src/Server.h
@@ -67,6 +67,14 @@ public:  // tolua_export
 	int  GetNumPlayers(void) const;
 	void SetMaxPlayers(int a_MaxPlayers) { m_MaxPlayers = a_MaxPlayers; }
 	
+	/** Check if the player is queued to be transferred to a World.
+	Returns true is Player is found in queue. */
+	bool IsPlayerInQueue(AString a_Username);
+	
+	/** Can login more than once with same username. 
+	Returns false if it is not allowed, true otherwise. */
+	bool DoesAllowMultiLogin(void) { return m_bAllowMultiLogin; }
+	
 	// Hardcore mode or not:
 	bool IsHardcore(void) const { return m_bIsHardcore; }
 
@@ -216,6 +224,9 @@ private:
 	int m_MaxPlayers;
 	bool m_bIsHardcore;
 	
+	/** True - allow same username to login more than once False - only once */
+	bool m_bAllowMultiLogin; 
+	
 	cTickThread m_TickThread;
 	cEvent m_RestartEvent;
 	
diff --git a/src/World.cpp b/src/World.cpp
index 911b32904..3dc083a2e 100644
--- a/src/World.cpp
+++ b/src/World.cpp
@@ -3669,3 +3669,4 @@ void cWorld::cChunkGeneratorCallbacks::CallHookChunkGenerated (cChunkDesc & a_Ch
 
 
 
+
diff --git a/src/World.h b/src/World.h
index d64be208e..2f51d60a1 100644
--- a/src/World.h
+++ b/src/World.h
@@ -808,7 +808,7 @@ public:
 	This function allows nesting and task-concurrency (multiple separate tasks can request ticking and as long
 	as at least one requests is active the chunk will be ticked). */
 	void SetChunkAlwaysTicked(int a_ChunkX, int a_ChunkZ, bool a_AlwaysTicked = true);  // tolua_export
-
+	
 private:
 
 	friend class cRoot;