Invert TCP connection model: client listens, server connects

The XPL2 protocol specifies that the JI2 controller initiates connections
to the client, not the other way around. Xpl2Client now listens on 3 ports
via QTcpServer and accepts inbound connections; MockServer connects out
with auto-retry on the 1s KA_PING tick.

QML API: startListening/stopListening, listening+connected properties,
host property removed. Mock server gains --host CLI arg.

1 files changed, 20 insertions, 15 deletions

diff --git a/src/Xpl2Client.h b/src/Xpl2Client.h
index 838c344..44edb65 100644
--- a/src/Xpl2Client.h
+++ b/src/Xpl2Client.h
@@ -11,17 +11,19 @@
 #include <QHash>
 #include <QObject>
 #include <QQmlEngine>
-#include <QTcpSocket>
+#include <QTcpServer>
 
 #include <functional>
 
+class QTcpSocket;
+
 class Xpl2Client : public QObject
 {
   Q_OBJECT
   QML_ELEMENT
   QML_SINGLETON
 
-  Q_PROPERTY (QString host READ host WRITE setHost NOTIFY hostChanged)
+  Q_PROPERTY (bool listening READ isListening NOTIFY listeningChanged)
   Q_PROPERTY (bool connected READ isConnected NOTIFY connectedChanged)
   Q_PROPERTY (int controllerId READ controllerId NOTIFY jcVersionReceived)
   Q_PROPERTY (
@@ -33,9 +35,7 @@ class Xpl2Client : public QObject
 public:
   explicit Xpl2Client (QObject *parent = nullptr);
 
-  QString host () const;
-  void setHost (const QString &host);
-
+  bool isListening () const;
   bool isConnected () const;
 
   int controllerId () const;
@@ -45,8 +45,8 @@ public:
 
   static void enableWireDebug ();
 
-  Q_INVOKABLE void connectToServer ();
-  Q_INVOKABLE void disconnectFromServer ();
+  Q_INVOKABLE void startListening ();
+  Q_INVOKABLE void stopListening ();
   /** Get the just connected Jetting Controller ID and Software Version. */
   Q_INVOKABLE void getJcVersion ();
   /** Query the specified printhead's version info. */
@@ -177,7 +177,7 @@ public:
   Q_INVOKABLE void imageCount ();
 
 signals:
-  void hostChanged ();
+  void listeningChanged ();
   void connectedChanged ();
   void errorOccurred (const QString &error);
   void statusMessage (const QString &message);
@@ -286,18 +286,20 @@ signals:
   void imagingStopResult (bool success);
 
 private slots:
-  void onSocketConnected ();
+  void onNewConnection ();
   void onSocketDisconnected ();
   void onSocketMessageReady ();
   void onSocketError (QAbstractSocket::SocketError error);
 
 private:
-  void sendCommand (QTcpSocket &socket, const QByteArray &command,
+  void setupServer (QTcpServer &server, quint16 port);
+  QTcpSocket *&socketForServer (QTcpServer *server);
+  void sendCommand (QTcpSocket *socket, const QByteArray &command,
                     const QVariantList &params = {});
   void dispatchCommandMessage (const Xpl2Protocol::ParsedMessage &msg);
   void dispatchImagingMessage (const Xpl2Protocol::ParsedMessage &msg);
   void dispatchStatusMessage (const Xpl2Protocol::ParsedMessage &msg);
-  void handleKaPing (QTcpSocket &socket);
+  void handleKaPing (QTcpSocket *socket);
   void handleGsJcVersion (const QVariantList &params);
   void handleGsPhVersion (const QVariantList &params);
   enum class ResponseShape
@@ -335,13 +337,16 @@ private:
   void updateConnectedState ();
   QString logTag (const QTcpSocket *socket) const;
 
-  QTcpSocket m_commandSocket;
-  QTcpSocket m_imagingSocket;
-  QTcpSocket m_statusSocket;
-  QString m_host = QStringLiteral ("127.0.0.1");
+  QTcpServer m_commandServer;
+  QTcpServer m_imagingServer;
+  QTcpServer m_statusServer;
+  QTcpSocket *m_commandSocket = nullptr;
+  QTcpSocket *m_imagingSocket = nullptr;
+  QTcpSocket *m_statusSocket = nullptr;
   quint16 m_commandPort = 9110;
   quint16 m_imagingPort = 9111;
   quint16 m_statusPort = 9112;
+  bool m_listening = false;
   bool m_connected = false;
   static bool s_wireDebug;
   int m_controllerId = 0;