Better error handling with smtp communication.

Adds log messages for a number of situations where sending an email will silently fail, in particular when attempting to create an unencrypted connection to an SMTP server that requires SSL

src/base/net/smtp.cpp

@@ -97,6 +97,13 @@ Smtp::Smtp(QObject *parent)
     , m_useSsl(false)
     , m_authType(AuthPlain)
 {
+    static bool needToRegisterMetaType = true;
+    
+    if (needToRegisterMetaType) {
+        qRegisterMetaType<QAbstractSocket::SocketError>();
+        needToRegisterMetaType = false;
+    }
+    
 #ifndef QT_NO_OPENSSL
     m_socket = new QSslSocket(this);
 #else
@@ -105,6 +112,7 @@ Smtp::Smtp(QObject *parent)
 
     connect(m_socket, SIGNAL(readyRead()), SLOT(readyRead()));
     connect(m_socket, SIGNAL(disconnected()), SLOT(deleteLater()));
+    connect(m_socket, SIGNAL(error(QAbstractSocket::SocketError)), SLOT(error(QAbstractSocket::SocketError)));
 
     // Test hmacMD5 function (http://www.faqs.org/rfcs/rfc2202.html)
     Q_ASSERT(hmacMD5("Jefe", "what do ya want for nothing?").toHex()
@@ -525,3 +533,11 @@ QString Smtp::getCurrentDateTime() const
     QString ret = weekDayStr + ", " + dayStr + " " + monthStr + " " + yearStr + " " + timeStr + " " + timeOffsetStr;
     return ret;
 }
+
+void Smtp::error(QAbstractSocket::SocketError socketError)
+{
+    // Getting a remote host closed error is apparently normal, even when successfully sending
+    // an email
+    if (socketError != QAbstractSocket::RemoteHostClosedError)
+        logError(m_socket->errorString());
+}

src/base/net/smtp.h

@@ -39,6 +39,8 @@
 #include <QObject>
 #include <QByteArray>
 #include <QHash>
+#include <QAbstractSocket>
+#include <QMetaType>
 
 QT_BEGIN_NAMESPACE
 class QTextStream;
@@ -64,6 +66,7 @@ namespace Net
 
     private slots:
         void readyRead();
+        void error(QAbstractSocket::SocketError socketError);
 
     private:
         enum States
@@ -123,4 +126,8 @@ namespace Net
     };
 }
 
+#ifndef QBT_USES_QT5
+Q_DECLARE_METATYPE(QAbstractSocket::SocketError)
+#endif
+
 #endif