cNetwork: Added link creation callback.

This allows the callback classes to store the link inside them and use it internally later on, mainly for sending data.

src/OSSupport/Network.h

@@ -13,6 +13,14 @@
 
 
 
+// fwd:
+class cTCPLink;
+typedef SharedPtr<cTCPLink> cTCPLinkPtr;
+
+
+
+
+
 /** Interface that provides the methods available on a single TCP connection. */
 class cTCPLink
 {
@@ -25,16 +33,20 @@ class cTCPLink
 		// Force a virtual destructor for all descendants:
 		virtual ~cCallbacks() {}
 
+		/** Called when the cTCPLink for the connection is created.
+		The callback may store the cTCPLink instance for later use, but it should remove it in OnError(), OnRemoteClosed() or right after Close(). */
+		virtual void OnLinkCreated(cTCPLinkPtr a_Link) = 0;
+
 		/** Called when there's data incoming from the remote peer. */
-		virtual void OnReceivedData(cTCPLink & a_Link, const char * a_Data, size_t a_Length) = 0;
+		virtual void OnReceivedData(const char * a_Data, size_t a_Length) = 0;
 
 		/** Called when the remote end closes the connection.
 		The link is still available for connection information query (IP / port).
 		Sending data on the link is not an error, but the data won't be delivered. */
-		virtual void OnRemoteClosed(cTCPLink & a_Link) = 0;
+		virtual void OnRemoteClosed(void) = 0;
 
 		/** Called when an error is detected on the connection. */
-		virtual void OnError(cTCPLink & a_Link, int a_ErrorCode, const AString & a_ErrorMsg) = 0;
+		virtual void OnError(int a_ErrorCode, const AString & a_ErrorMsg) = 0;
 	};
 	typedef SharedPtr<cCallbacks> cCallbacksPtr;
 

src/OSSupport/ServerHandleImpl.cpp

@@ -283,6 +283,8 @@ void cServerHandleImpl::Callback(evconnlistener * a_Listener, evutil_socket_t a_
 		cCSLock Lock(Self->m_CS);
 		Self->m_Connections.push_back(Link);
 	}  // Lock(m_CS)
+	LinkCallbacks->OnLinkCreated(Link);
+	Link->Enable();
 
 	// Call the OnAccepted callback:
 	Self->m_ListenCallbacks->OnAccepted(*Link);

src/OSSupport/TCPLinkImpl.cpp

@@ -20,9 +20,6 @@ cTCPLinkImpl::cTCPLinkImpl(cTCPLink::cCallbacksPtr a_LinkCallbacks):
 	m_BufferEvent(bufferevent_socket_new(cNetworkSingleton::Get().GetEventBase(), -1, BEV_OPT_CLOSE_ON_FREE)),
 	m_Server(nullptr)
 {
-	// Create the LibEvent handle, but don't assign a socket to it yet (will be assigned within Connect() method):
-	bufferevent_setcb(m_BufferEvent, ReadCallback, nullptr, EventCallback, this);
-	bufferevent_enable(m_BufferEvent, EV_READ | EV_WRITE);
 }
 
 
@@ -37,10 +34,6 @@ cTCPLinkImpl::cTCPLinkImpl(evutil_socket_t a_Socket, cTCPLink::cCallbacksPtr a_L
 	// Update the endpoint addresses:
 	UpdateLocalAddress();
 	UpdateAddress(a_Address, a_AddrLen, m_RemoteIP, m_RemotePort);
-
-	// Create the LibEvent handle:
-	bufferevent_setcb(m_BufferEvent, ReadCallback, nullptr, EventCallback, this);
-	bufferevent_enable(m_BufferEvent, EV_READ | EV_WRITE);
 }
 
 
@@ -65,6 +58,8 @@ cTCPLinkImplPtr cTCPLinkImpl::Connect(const AString & a_Host, UInt16 a_Port, cTC
 	cTCPLinkImplPtr res{new cTCPLinkImpl(a_LinkCallbacks)};  // Cannot use std::make_shared here, constructor is not accessible
 	res->m_ConnectCallbacks = a_ConnectCallbacks;
 	cNetworkSingleton::Get().AddLink(res);
+	res->m_Callbacks->OnLinkCreated(res);
+	res->Enable();
 
 	// If a_Host is an IP address, schedule a connection immediately:
 	sockaddr_storage sa;
@@ -107,6 +102,17 @@ cTCPLinkImplPtr cTCPLinkImpl::Connect(const AString & a_Host, UInt16 a_Port, cTC
 
 
 
+void cTCPLinkImpl::Enable(void)
+{
+	// Set the LibEvent callbacks and enable processing:
+	bufferevent_setcb(m_BufferEvent, ReadCallback, nullptr, EventCallback, this);
+	bufferevent_enable(m_BufferEvent, EV_READ | EV_WRITE);
+}
+
+
+
+
+
 bool cTCPLinkImpl::Send(const void * a_Data, size_t a_Length)
 {
 	return (bufferevent_write(m_BufferEvent, a_Data, a_Length) == 0);
@@ -160,7 +166,7 @@ void cTCPLinkImpl::ReadCallback(bufferevent * a_BufferEvent, void * a_Self)
 	size_t length;
 	while ((length = bufferevent_read(a_BufferEvent, data, sizeof(data))) > 0)
 	{
-		Self->m_Callbacks->OnReceivedData(*Self, data, length);
+		Self->m_Callbacks->OnReceivedData(data, length);
 	}
 }
 
@@ -189,7 +195,7 @@ void cTCPLinkImpl::EventCallback(bufferevent * a_BufferEvent, short a_What, void
 		}
 		else
 		{
-			Self->m_Callbacks->OnError(*Self, err, evutil_socket_error_to_string(err));
+			Self->m_Callbacks->OnError(err, evutil_socket_error_to_string(err));
 			if (Self->m_Server == nullptr)
 			{
 				cNetworkSingleton::Get().RemoveLink(Self);
@@ -219,7 +225,7 @@ void cTCPLinkImpl::EventCallback(bufferevent * a_BufferEvent, short a_What, void
 	// If the connection has been closed, call the link callback and remove the connection:
 	if (a_What & BEV_EVENT_EOF)
 	{
-		Self->m_Callbacks->OnRemoteClosed(*Self);
+		Self->m_Callbacks->OnRemoteClosed();
 		if (Self->m_Server != nullptr)
 		{
 			Self->m_Server->RemoveLink(Self);

src/OSSupport/TCPLinkImpl.h

@@ -37,7 +37,8 @@ class cTCPLinkImpl:
 public:
 	/** Creates a new link based on the given socket.
 	Used for connections accepted in a server using cNetwork::Listen().
-	a_Address and a_AddrLen describe the remote peer that has connected. */
+	a_Address and a_AddrLen describe the remote peer that has connected.
+	The link is created disabled, you need to call Enable() to start the regular communication. */
 	cTCPLinkImpl(evutil_socket_t a_Socket, cCallbacksPtr a_LinkCallbacks, cServerHandleImpl * a_Server, const sockaddr * a_Address, socklen_t a_AddrLen);
 
 	/** Destroys the LibEvent handle representing the link. */
@@ -48,6 +49,11 @@ class cTCPLinkImpl:
 	Returns a link that has the connection request queued, or NULL for failure. */
 	static cTCPLinkImplPtr Connect(const AString & a_Host, UInt16 a_Port, cTCPLink::cCallbacksPtr a_LinkCallbacks, cNetwork::cConnectCallbacksPtr a_ConnectCallbacks);
 
+	/** Enables communication over the link.
+	Links are created with communication disabled, so that creation callbacks can be called first.
+	This function then enables the regular communication to be reported. */
+	void Enable(void);
+
 	// cTCPLink overrides:
 	virtual bool Send(const void * a_Data, size_t a_Length) override;
 	virtual AString GetLocalIP(void) const override { return m_LocalIP; }
@@ -85,7 +91,8 @@ class cTCPLinkImpl:
 
 	/** Creates a new link to be queued to connect to a specified host:port.
 	Used for outgoing connections created using cNetwork::Connect().
-	To be used only by the Connect() factory function. */
+	To be used only by the Connect() factory function.
+	The link is created disabled, you need to call Enable() to start the regular communication. */
 	cTCPLinkImpl(const cCallbacksPtr a_LinkCallbacks);
 
 	/** Callback that LibEvent calls when there's data available from the remote peer. */

tests/Network/EchoServer.cpp

@@ -16,33 +16,55 @@
 class cEchoLinkCallbacks:
 	public cTCPLink::cCallbacks
 {
-	virtual void OnReceivedData(cTCPLink & a_Link, const char * a_Data, size_t a_Size) override
+	// cTCPLink::cCallbacks overrides:
+	virtual void OnLinkCreated(cTCPLinkPtr a_Link) override
 	{
+		ASSERT(m_Link == nullptr);
+		m_Link = a_Link;
+	}
+
+
+	virtual void OnReceivedData(const char * a_Data, size_t a_Size) override
+	{
+		ASSERT(m_Link != nullptr);
+
 		// Echo the incoming data back to outgoing data:
-		LOGD("%p (%s:%d): Data received (%u bytes), echoing back.", &a_Link, a_Link.GetRemoteIP().c_str(), a_Link.GetRemotePort(), static_cast<unsigned>(a_Size));
-		a_Link.Send(a_Data, a_Size);
+		LOGD("%p (%s:%d): Data received (%u bytes), echoing back.", m_Link.get(), m_Link->GetRemoteIP().c_str(), m_Link->GetRemotePort(), static_cast<unsigned>(a_Size));
+		m_Link->Send(a_Data, a_Size);
 		LOGD("Echo queued");
 
 		// Search for a Ctrl+Z, if found, drop the connection:
 		for (size_t i = 0; i < a_Size; i++)
 		{
 			if (a_Data[i] == '\x1a')
 			{
-				a_Link.Close();
+				m_Link->Close();
+				m_Link.reset();
 				return;
 			}
 		}
 	}
 
-	virtual void OnRemoteClosed(cTCPLink & a_Link) override
+
+	virtual void OnRemoteClosed(void) override
 	{
-		LOGD("%p (%s:%d): Remote has closed the connection.", &a_Link, a_Link.GetRemoteIP().c_str(), a_Link.GetRemotePort());
+		ASSERT(m_Link != nullptr);
+
+		LOGD("%p (%s:%d): Remote has closed the connection.", m_Link.get(), m_Link->GetRemoteIP().c_str(), m_Link->GetRemotePort());
+		m_Link.reset();
 	}
 
-	virtual void OnError(cTCPLink & a_Link, int a_ErrorCode, const AString & a_ErrorMsg) override
+
+	virtual void OnError(int a_ErrorCode, const AString & a_ErrorMsg) override
 	{
-		LOGD("%p (%s:%d): Error %d in the cEchoLinkCallbacks: %s", &a_Link, a_Link.GetRemoteIP().c_str(), a_Link.GetRemotePort(), a_ErrorCode, a_ErrorMsg.c_str());
+		ASSERT(m_Link != nullptr);
+
+		LOGD("%p (%s:%d): Error %d in the cEchoLinkCallbacks: %s", m_Link.get(), m_Link->GetRemoteIP().c_str(), m_Link->GetRemotePort(), a_ErrorCode, a_ErrorMsg.c_str());
+		m_Link.reset();
 	}
+
+	/** The link attached to this callbacks instance. */
+	cTCPLinkPtr m_Link;
 };
 
 

tests/Network/Google.cpp

@@ -49,24 +49,39 @@ class cDumpCallbacks:
 	public cTCPLink::cCallbacks
 {
 	cEvent & m_Event;
+	cTCPLinkPtr m_Link;
 
-	virtual void OnReceivedData(cTCPLink & a_Link, const char * a_Data, size_t a_Size) override
+	virtual void OnLinkCreated(cTCPLinkPtr a_Link) override
 	{
+		ASSERT(m_Link == nullptr);
+		m_Link = a_Link;
+	}
+
+	virtual void OnReceivedData(const char * a_Data, size_t a_Size) override
+	{
+		ASSERT(m_Link != nullptr);
+
 		// Log the incoming data size:
 		AString Hex;
 		CreateHexDump(Hex, a_Data, a_Size, 16);
 		LOGD("Incoming data: %u bytes:\n%s", static_cast<unsigned>(a_Size), Hex.c_str());
 	}
 
-	virtual void OnRemoteClosed(cTCPLink & a_Link) override
+	virtual void OnRemoteClosed(void) override
 	{
+		ASSERT(m_Link != nullptr);
+
 		LOGD("Remote has closed the connection.");
+		m_Link.reset();
 		m_Event.Set();
 	}
 
-	virtual void OnError(cTCPLink & a_Link, int a_ErrorCode, const AString & a_ErrorMsg) override
+	virtual void OnError(int a_ErrorCode, const AString & a_ErrorMsg) override
 	{
+		ASSERT(m_Link != nullptr);
+
 		LOGD("Error %d (%s) in the cDumpCallbacks.", a_ErrorCode, a_ErrorMsg.c_str());
+		m_Link.reset();
 		m_Event.Set();
 	}