feat: Add JoinRole proxy role type

proxyrole.cpp

@@ -41,9 +41,52 @@ void ProxyRole::invalidate()
     Q_EMIT invalidated();
 }
 
+QStringList JoinRole::roleNames() const
+{
+    return m_roleNames;
+}
+
+void JoinRole::setRoleNames(const QStringList& roleNames)
+{
+    if (m_roleNames == roleNames)
+        return;
+
+    m_roleNames = roleNames;
+    Q_EMIT roleNamesChanged();
+    invalidate();
+}
+
+QString JoinRole::separator() const
+{
+    return m_separator;
+}
+
+void JoinRole::setSeparator(const QString& separator)
+{
+    if (m_separator == separator)
+        return;
+
+    m_separator = separator;
+    Q_EMIT separatorChanged();
+    invalidate();
+}
+
+QVariant JoinRole::data(const QModelIndex &sourceIndex, const QQmlSortFilterProxyModel &proxyModel)
+{
+    QString result;
+
+    for (const QString& roleName : m_roleNames)
+        result += proxyModel.sourceData(sourceIndex, roleName).toString() + m_separator;
+
+    if (!m_roleNames.isEmpty())
+        result.chop(m_separator.length());
+
+    return result;
+}
 
 void registerProxyRoleTypes() {
     qmlRegisterUncreatableType<ProxyRole>("SortFilterProxyModel", 0, 2, "ProxyRole", "ProxyRole is an abstract class");
+    qmlRegisterType<JoinRole>("SortFilterProxyModel", 0, 2, "JoinRole");
 }
 
 Q_COREAPP_STARTUP_FUNCTION(registerProxyRoleTypes)

proxyrole.h

@@ -35,6 +35,32 @@ private:
     QMutex m_mutex;
 };
 
+class JoinRole : public ProxyRole
+{
+    Q_OBJECT
+    Q_PROPERTY(QStringList roleNames READ roleNames WRITE setRoleNames NOTIFY roleNamesChanged)
+    Q_PROPERTY(QString separator READ separator WRITE setSeparator NOTIFY separatorChanged)
+
+public:
+    using ProxyRole::ProxyRole;
+
+    QStringList roleNames() const;
+    void setRoleNames(const QStringList& roleNames);
+
+    QString separator() const;
+    void setSeparator(const QString& separator);
+
+Q_SIGNALS:
+    void roleNamesChanged();
+
+    void separatorChanged();
+
+private:
+    QStringList m_roleNames;
+    QVariant data(const QModelIndex& sourceIndex, const QQmlSortFilterProxyModel& proxyModel) override;
+    QString m_separator = " ";
+};
+
 }
 
 #endif // PROXYROLE_H

tests/SortFilterProxyModel.pro

@@ -23,4 +23,5 @@ OTHER_FILES += \
     tst_builtins.qml \
     tst_rolesorter.qml \
     tst_stringsorter.qml \
-    tst_proxyroles.qml
+    tst_proxyroles.qml \
+    tst_joinrole.qml

tests/tst_joinrole.qml

@@ -0,0 +1,45 @@
+import QtQuick 2.0
+import QtQml 2.2
+import QtTest 1.1
+import SortFilterProxyModel 0.2
+import QtQml 2.2
+
+Item {
+    ListModel {
+        id: listModel
+        ListElement { firstName: "Justin"; lastName: "Timberlake" }
+    }
+
+    SortFilterProxyModel {
+        id: testModel
+        sourceModel: listModel
+
+        proxyRoles: JoinRole {
+            id: joinRole
+            name: "fullName"
+            roleNames: ["firstName", "lastName"]
+        }
+    }
+
+    Instantiator {
+        id: instantiator
+        model: testModel
+        QtObject {
+            property string fullName: model.fullName
+        }
+    }
+
+    TestCase {
+        name: "JoinRole"
+
+        function test_joinRole() {
+            compare(instantiator.object.fullName, "Justin Timberlake");
+            listModel.setProperty(0, "lastName", "Bieber");
+            compare(instantiator.object.fullName, "Justin Bieber");
+            joinRole.roleNames = ["lastName", "firstName"];
+            compare(instantiator.object.fullName, "Bieber Justin");
+            joinRole.separator = " - ";
+            compare(instantiator.object.fullName, "Bieber - Justin");
+        }
+    }
+}