uic: Adapt connection syntax to Python

Extend WriteInitialization::findDeclaration() to return the class name
(on this occasion preparing for generating Qt 5 connection syntax) and
add a helper function for formatting the connection.

Task-number: PYSIDE-797
Change-Id: I7507f604c8275c93d347b7a6a5d5b5a2a5f3ffd5
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

src/tools/uic/cpp/cppwriteinitialization.cpp

@@ -2430,34 +2430,42 @@ QTextStream &WriteInitialization::autoTrOutput(const DomString *str, const QStri
     return m_output;
 }
 
-QString WriteInitialization::findDeclaration(const QString &name)
+WriteInitialization::Declaration WriteInitialization::findDeclaration(const QString &name)
 {
     if (const DomWidget *widget = m_driver->widgetByName(name))
-        return m_driver->findOrInsertWidget(widget);
+        return {m_driver->findOrInsertWidget(widget), widget->attributeClass()};
     if (const DomAction *action = m_driver->actionByName(name))
-        return m_driver->findOrInsertAction(action);
+        return {m_driver->findOrInsertAction(action), QStringLiteral("QAction")};
     if (const DomButtonGroup *group = m_driver->findButtonGroup(name))
-        return m_driver->findOrInsertButtonGroup(group);
-    return QString();
+         return {m_driver->findOrInsertButtonGroup(group), QStringLiteral("QButtonGroup")};
+    return {};
 }
 
 void WriteInitialization::acceptConnection(DomConnection *connection)
 {
-    const QString sender = findDeclaration(connection->elementSender());
-    const QString receiver = findDeclaration(connection->elementReceiver());
+    const QString senderName = connection->elementSender();
+    const QString receiverName = connection->elementReceiver();
 
-    if (sender.isEmpty() || receiver.isEmpty())
+    const auto senderDecl = findDeclaration(senderName);
+    const auto receiverDecl = findDeclaration(receiverName);
+
+    if (senderDecl.name.isEmpty() || receiverDecl.name.isEmpty()) {
+        QString message;
+        QTextStream(&message) << m_option.messagePrefix()
+            << ": Warning: Invalid signal/slot connection: \""
+            << senderName << "\" -> \"" << receiverName << "\".";
+        fprintf(stderr, "%s\n", qPrintable(message));
         return;
+    }
 
-    m_output << m_indent << "QObject::connect("
-        << sender
-        << ", "
-        << "SIGNAL("<<connection->elementSignal()<<')'
-        << ", "
-        << receiver
-        << ", "
-        << "SLOT("<<connection->elementSlot()<<')'
-        << ");\n";
+    language::SignalSlot theSignal{senderDecl.name, connection->elementSignal(),
+                                   senderDecl.className};
+    language::SignalSlot theSlot{receiverDecl.name, connection->elementSlot(),
+                                 receiverDecl.className};
+
+    m_output << m_indent;
+    language::formatConnection(m_output, theSignal, theSlot);
+    m_output << ";\n";
 }
 
 static void generateMultiDirectiveBegin(QTextStream &outputStream, const QSet<QString> &directives)

src/tools/uic/cpp/cppwriteinitialization.h

@@ -220,7 +220,13 @@ private:
     QString disableSorting(DomWidget *w, const QString &varName);
     void enableSorting(DomWidget *w, const QString &varName, const QString &tempName);
 
-    QString findDeclaration(const QString &name);
+    struct Declaration
+    {
+        QString name;
+        QString className;
+    };
+
+    Declaration findDeclaration(const QString &name);
 
 private:
     QString writeFontProperties(const DomFont *f);

src/tools/uic/shared/language.cpp

@@ -384,4 +384,21 @@ void _formatStackVariable(QTextStream &str, const char *className, QStringView v
     }
 }
 
+void formatConnection(QTextStream &str, const SignalSlot &sender, const SignalSlot &receiver)
+{
+    switch (language()) {
+    case Language::Cpp:
+        str << "QObject::connect(" << sender.name << ", SIGNAL("<< sender.signature
+            << "), " << receiver.name << ", SLOT("<< receiver.signature << "))";
+        break;
+    case Language::Python:
+        str << sender.name << '.'
+            << sender.signature.leftRef(sender.signature.indexOf(QLatin1Char('(')))
+            << ".connect(" << receiver.name << '.'
+            << receiver.signature.leftRef(receiver.signature.indexOf(QLatin1Char('(')))
+            << ')';
+        break;
+    }
+}
+
 } // namespace language

src/tools/uic/shared/language.h

@@ -31,6 +31,7 @@
 
 #include <QtCore/qstring.h>
 #include <QtCore/qstringview.h>
+#include <QtCore/qstring.h>
 
 QT_FORWARD_DECLARE_CLASS(QTextStream)
 
@@ -189,6 +190,15 @@ inline QTextStream &operator<<(QTextStream &str, const _stackVariable<withInitPa
 using stackVariable = _stackVariable<false>;
 using stackVariableWithInitParameters = _stackVariable<true>;
 
+struct SignalSlot
+{
+    QString name;
+    QString signature;
+    QString className;
+};
+
+void formatConnection(QTextStream &str, const SignalSlot &sender, const SignalSlot &receiver);
+
 } // namespace language
 
 #endif // LANGUAGE_H