Added 'TakeOver' Option

NetImguiServerApp can now forcefully take over a connection to a client already connected to another server. A button with 'TakeOver' appear in the Client List letting the user connect despite an active connection.

Code/Client/NetImgui_Api.h

@@ -4,12 +4,12 @@
 //! @Name		: NetImgui
 //=================================================================================================
 //! @author		: Sammy Fatnassi
-//! @date		: 2023/12/2
+//! @date		: 2024/05/26
 //!	@version	: v1.9.7
 //! @Details	: For integration info : https://github.com/sammyfreg/netImgui/wiki
 //=================================================================================================
-#define NETIMGUI_VERSION		"1.9.7"	// Update to samples, texture creation fix
-#define NETIMGUI_VERSION_NUM	10907
+#define NETIMGUI_VERSION		"1.9.8"	// Added 'TakeOver' connection option
+#define NETIMGUI_VERSION_NUM	10908
 
 
 
@@ -62,7 +62,7 @@
 // (either always included in NetImgui_config.h or have it included after Imgui.h in your cpp)
 #if !defined(IMGUI_VERSION)
 	#undef	NETIMGUI_ENABLED
-	#define	NETIMGUI_ENABLED 0
+	#define NETIMGUI_ENABLED 0
 #endif
 
 #if NETIMGUI_ENABLED

Code/Client/Private/NetImgui_Api.cpp

@@ -56,8 +56,8 @@ bool ConnectToApp(const char* clientName, const char* ServerHost, uint32_t serve
 	if (client.mpSocketPending.load() != nullptr)
 	{				
 		client.ContextInitialize();
-		threadFunction		= threadFunction == nullptr ? DefaultStartCommunicationThread : threadFunction;
-		threadFunction(Client::CommunicationsClient, &client);
+		threadFunction = threadFunction == nullptr ? DefaultStartCommunicationThread : threadFunction;
+		threadFunction(Client::CommunicationsConnect, &client);
 	}
 
 	return client.IsActive();
@@ -81,11 +81,11 @@ bool ConnectFromApp(const char* clientName, uint32_t serverPort, ThreadFunctPtr
 	StringCopy(client.mName, (clientName == nullptr || clientName[0] == 0 ? "Unnamed" : clientName));
 	client.mpSocketPending			= Network::ListenStart(serverPort);
 	client.mFontCreationFunction	= FontCreateFunction;
+	client.mThreadFunction			= (threadFunction == nullptr) ? DefaultStartCommunicationThread : threadFunction;
 	if (client.mpSocketPending.load() != nullptr)
 	{				
 		client.ContextInitialize();
-		threadFunction		= threadFunction == nullptr ? DefaultStartCommunicationThread : threadFunction;
-		threadFunction(Client::CommunicationsHost, &client);
+		client.mThreadFunction(Client::CommunicationsHost, &client);
 	}
 
 	return client.IsActive();

Code/Client/Private/NetImgui_Client.cpp

@@ -75,35 +75,6 @@ static void SetClipboardTextFn_NetImguiImpl(void* user_data_ctx, const char* tex
 	}
 }
 
-//=================================================================================================
-// COMMUNICATIONS INITIALIZE
-// Initialize a new connection to a RemoteImgui server
-//=================================================================================================
-bool Communications_Initialize(ClientInfo& client)
-{
-	CmdVersion cmdVersionSend, cmdVersionRcv;
-	StringCopy(cmdVersionSend.mClientName, client.mName);
-	bool bResultSend	= Network::DataSend(client.mpSocketPending, &cmdVersionSend, cmdVersionSend.mHeader.mSize);
-	bool bResultRcv		= Network::DataReceive(client.mpSocketPending, &cmdVersionRcv, sizeof(cmdVersionRcv));
-	bool mbConnected	= bResultRcv && bResultSend && 
-						  cmdVersionRcv.mHeader.mType	== cmdVersionSend.mHeader.mType && 
-						  cmdVersionRcv.mVersion		== cmdVersionSend.mVersion &&
-						  cmdVersionRcv.mWCharSize		== cmdVersionSend.mWCharSize;	
-	if(mbConnected)
-	{				
-		for(auto& texture : client.mTextures)
-		{
-			texture.mbSent = false;
-		}
-
-		client.mbHasTextureUpdate			= true;								// Force sending the client textures
-		client.mBGSettingSent.mTextureId	= client.mBGSetting.mTextureId-1u;	// Force sending the Background settings (by making different than current settings)
-		client.mpSocketComs					= client.mpSocketPending.exchange(nullptr);
-		client.mFrameIndex					= 0;
-	}
-	return client.mpSocketComs.load() != nullptr;
-}
-
 //=================================================================================================
 // INCOM: INPUT
 // Receive new keyboard/mouse/screen resolution input to pass on to dearImgui
@@ -332,16 +303,66 @@ bool Communications_Outgoing(ClientInfo& client)
 }
 
 //=================================================================================================
-// COMMUNICATIONS THREAD 
+// COMMUNICATIONS INITIALIZE
+// Initialize a new connection to a RemoteImgui server
 //=================================================================================================
-void CommunicationsClient(void* pClientVoid)
-{	
+bool Communications_Initialize(ClientInfo& client)
+{
+	CmdVersion cmdVersionSend, cmdVersionRcv;
+	bool bResultRcv		= Network::DataReceive(client.mpSocketPending, &cmdVersionRcv, sizeof(cmdVersionRcv));
+	bool bForceConnect	= client.mServerForceConnectEnabled && (cmdVersionRcv.mFlags & static_cast<uint8_t>(CmdVersion::eFlags::ConnectForce)) != 0;
+	bool bCanConnect	= bResultRcv && 
+					 	  cmdVersionRcv.mHeader.mType	== cmdVersionSend.mHeader.mType && 
+					 	  cmdVersionRcv.mVersion		== cmdVersionSend.mVersion &&
+						  cmdVersionRcv.mWCharSize		== cmdVersionSend.mWCharSize &&
+						  (!client.IsConnected() || bForceConnect);
+
+	StringCopy(cmdVersionSend.mClientName, client.mName);
+	cmdVersionSend.mFlags	= client.IsConnected() && !bCanConnect ? static_cast<uint8_t>(CmdVersion::eFlags::IsConnected): 0;
+	cmdVersionSend.mFlags	|= client.IsConnected() && !client.mServerForceConnectEnabled ? static_cast<uint8_t>(CmdVersion::eFlags::IsUnavailable) : 0;
+	bool bResultSend		= Network::DataSend(client.mpSocketPending, &cmdVersionSend, cmdVersionSend.mHeader.mSize);
+
+	if(bCanConnect && bResultSend)
+	{
+		Network::SocketInfo* pNewConnect = client.mpSocketPending.exchange(nullptr);
+		if( client.IsConnected() )
+		{
+			if( bForceConnect )
+			{
+				client.mbDisconnectRequest = true;
+				while( client.IsConnected() );
+			}
+			else
+			{
+				NetImgui::Internal::Network::Disconnect(pNewConnect);
+				return false;
+			}
+		}
+
+		for(auto& texture : client.mTextures)
+		{
+			texture.mbSent = false;
+		}
+		client.mbHasTextureUpdate			= true;								// Force sending the client textures
+		client.mBGSettingSent.mTextureId	= client.mBGSetting.mTextureId-1u;	// Force sending the Background settings (by making different than current settings)
+		client.mpSocketComs					= pNewConnect;
+		client.mFrameIndex					= 0;
+		client.mServerForceConnectEnabled	= (cmdVersionRcv.mFlags & static_cast<uint8_t>(CmdVersion::eFlags::ConnectExclusive)) == 0;
+	}
+	return client.mpSocketPending.load() == nullptr;
+}
+
+//=================================================================================================
+// COMMUNICATIONS MAIN LOOP 
+//=================================================================================================
+void Communications_Loop(void* pClientVoid)
+{
+	IM_ASSERT(pClientVoid != nullptr);
 	ClientInfo* pClient				= reinterpret_cast<ClientInfo*>(pClientVoid);
-	pClient->mbClientThreadActive	= true;
-	pClient->mbDisconnectRequest	= false;
-	Communications_Initialize(*pClient);
 	bool bConnected					= pClient->IsConnected();
-
+	pClient->mbDisconnectRequest 	= false;
+	pClient->mbClientThreadActive 	= true;
+
 	while( bConnected && !pClient->mbDisconnectRequest )
 	{
 		std::this_thread::sleep_for(std::chrono::milliseconds(1));
@@ -350,11 +371,27 @@ void CommunicationsClient(void* pClientVoid)
 	}
 
 	pClient->KillSocketComs();
-	pClient->mbClientThreadActive	= false;
+	pClient->mbClientThreadActive = false;
+}
+
+//=================================================================================================
+// COMMUNICATIONS CONNECT THREAD : Reach out and connect to a NetImGuiServer
+//=================================================================================================
+void CommunicationsConnect(void* pClientVoid)
+{
+	IM_ASSERT(pClientVoid != nullptr);
+	ClientInfo* pClient				= reinterpret_cast<ClientInfo*>(pClientVoid);
+	pClient->mbClientThreadActive 	= true;
+	if( Communications_Initialize(*pClient) )
+	{
+		Communications_Loop(pClientVoid);
+	}
+	pClient->mbClientThreadActive 	= false;
 }
 
 //=================================================================================================
-// COMMUNICATIONS WAIT THREAD 
+// COMMUNICATIONS HOST THREAD : Waiting NetImGuiServer reaching out to us. 
+//								Launch a new com loop when connection is established
 //=================================================================================================
 void CommunicationsHost(void* pClientVoid)
 {
@@ -366,18 +403,13 @@ void CommunicationsHost(void* pClientVoid)
 	while( pClient->mpSocketListen.load() != nullptr && !pClient->mbDisconnectRequest )
 	{
 		pClient->mpSocketPending = Network::ListenConnect(pClient->mpSocketListen);
-		if( pClient->mpSocketPending.load() != nullptr )
+		if( !pClient->mbDisconnectRequest &&
+			pClient->mpSocketPending.load() != nullptr &&
+			Communications_Initialize(*pClient) )
 		{
-			bool bConnected = Communications_Initialize(*pClient);
-			while (bConnected && !pClient->mbDisconnectRequest)
-			{
-				std::this_thread::sleep_for(std::chrono::milliseconds(1));
-				//std::this_thread::yield();
-				bConnected	= Communications_Outgoing(*pClient) && Communications_Incoming(*pClient);
-			}
-			pClient->KillSocketComs();
+			pClient->mThreadFunction(Client::Communications_Loop, pClient);
 		}
-		std::this_thread::sleep_for(std::chrono::milliseconds(10));	// Prevents this thread from taking entire core, waiting on server connection
+		std::this_thread::sleep_for(std::chrono::milliseconds(16));	// Prevents this thread from taking entire core, waiting on server connection
 	}
 	pClient->KillSocketListen();
 	pClient->mbListenThreadActive	= false;

Code/Client/Private/NetImgui_Client.h

@@ -113,7 +113,8 @@ struct ClientInfo
 	uint8_t								mClientCompressionMode		= eCompressionMode::kUseServerSetting;
 	bool								mServerCompressionEnabled	= false;	// If Server would like compression to be enabled (mClientCompressionMode value can override this value)
 	bool								mServerCompressionSkip		= false;	// Force ignore compression setting for 1 frame
-	char								PADDING[1];
+	bool 								mServerForceConnectEnabled	= true;		// If another NetImguiServer can take connection away from the one currently active
+	ThreadFunctPtr						mThreadFunction				= nullptr;	// Function to use when laucnhing new threads
 	FontCreationFuncPtr					mFontCreationFunction		= nullptr;	// Method to call to generate the remote ImGui font. By default, re-use the local font, but this doesn't handle native DPI scaling on remote server
 	float								mFontCreationScaling		= 1.f;		// Last font scaling used when generating the NetImgui font
 	InputState							mPreviousInputState;					// Keeping track of last keyboard/mouse state
@@ -136,9 +137,9 @@ struct ClientInfo
 };
 
 //=============================================================================
-// Main communication thread, that should be started in its own thread
+// Main communication loop threads that are run in separate threads
 //=============================================================================
-void CommunicationsClient(void* pClientVoid);
+void CommunicationsConnect(void* pClientVoid);
 void CommunicationsHost(void* pClientVoid);
 
 }}} //namespace NetImgui::Internal::Client

Code/Client/Private/NetImgui_CmdPackets.h

@@ -46,13 +46,20 @@ struct alignas(8) CmdVersion
 		CustomTexture		= 12,	// Added a 'custom' texture format to let user potentially handle their how format
 		DPIScale			= 13,	// Server now handle monitor DPI
 		Clipboard			= 14,	// Added clipboard support between server/client
+		ForceReconnect		= 15,	// Server can now take over the connection from another server
 		// Insert new version here
 
 		//--------------------------------
 		_count,
 		_current			= _count -1
 	};
-
+	enum class eFlags : uint8_t
+	{
+		IsUnavailable 		= 0x01,	// Client telling Server it cannot be used
+		IsConnected 		= 0x02,	// Client telling Server there's already a valid connection (can potentially be taken over if !IsUnavailable)
+		ConnectForce		= 0x04,	// Server telling Client it want to take over connection if there's already one
+		ConnectExclusive	= 0x08,	// Server telling Client that once connected, others servers should be denied access
+	};
 	CmdHeader	mHeader					= CmdHeader(CmdHeader::eCommands::Version, sizeof(CmdVersion));
 	eVersion	mVersion				= eVersion::_current;
 	char		mClientName[64]			= {};
@@ -61,7 +68,8 @@ struct alignas(8) CmdVersion
 	uint32_t	mImguiVerID				= IMGUI_VERSION_NUM;
 	uint32_t	mNetImguiVerID			= NETIMGUI_VERSION_NUM;
 	uint8_t		mWCharSize				= static_cast<uint8_t>(sizeof(ImWchar));
-	char		PADDING[3];
+	uint8_t 	mFlags 					= 0;
+	char		PADDING[2];
 };
 
 struct alignas(8) CmdInput

Code/Client/Private/NetImgui_Shared.h

@@ -94,6 +94,7 @@ class ExchangePtr
 	inline TType*		Release();
 	inline void			Assign(TType*& pNewData);
 	inline void			Free();
+	inline bool 		IsNull()const { return mpData.load() != nullptr; }
 private:						
 	std::atomic<TType*> mpData;
 

Code/Sample/SampleCompression/SampleCompression.cpp

@@ -90,7 +90,7 @@ void CustomThreadLauncher(void ComFunctPtr(void*), void* pClient)
 #endif
 	//=========================================================================================
 	// @SAMPLE_EDIT	
-	if( ComFunctPtr == NetImgui::Internal::Client::CommunicationsClient ){
+	if( ComFunctPtr == NetImgui::Internal::Client::CommunicationsConnect ){
 		std::thread(CustomCommunicationsClient, pClient).detach();
 		gMetric_ConnectTo = true;
 		return;