moc: Allow out-of-line storage for Q_PRIVATE_QPROPERTY

If you pass "STORED false" the name is interpreted as function to be
invoked in order to access the property. This allows storage of a
property in a lazily allocated data type.

Change-Id: I4d3a9cac6985c6419ce687868cb74b91921595a6
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

4 files changed, 59 insertions, 14 deletions

diff --git a/src/tools/moc/generator.cpp b/src/tools/moc/generator.cpp
index 39640b6f68..4f420b8467 100644
--- a/src/tools/moc/generator.cpp
+++ b/src/tools/moc/generator.cpp
@@ -1555,7 +1555,7 @@ void Generator::generateQPropertyApi()
                 cdef->qualified.constData(),
                 property.name.constData());
         printAccessor(/*const*/true);
-        fprintf(out, "    return thisPtr->%s->%s.value();\n", property.accessor.constData(), property.name.constData());
+        fprintf(out, "    return thisPtr->%s->%s.value();\n", property.accessor.constData(), property.storage.constData());
         fprintf(out, "}\n");
 
         // property value setter
@@ -1564,7 +1564,7 @@ void Generator::generateQPropertyApi()
                 property.name.constData(),
                 property.type.name.constData());
         printAccessor();
-        fprintf(out, "    return thisPtr->%s->%s.setValue(thisPtr->%s, value);\n", property.accessor.constData(), property.name.constData(), property.accessor.constData());
+        fprintf(out, "    return thisPtr->%s->%s.setValue(thisPtr->%s, value);\n", property.accessor.constData(), property.storage.constData(), property.accessor.constData());
         fprintf(out, "}\n");
 
         // property value move setter
@@ -1573,7 +1573,7 @@ void Generator::generateQPropertyApi()
                 property.name.constData(),
                 property.type.name.constData());
         printAccessor();
-        fprintf(out, "    return thisPtr->%s->%s.setValue(thisPtr->%s, std::move(value));\n", property.accessor.constData(), property.name.constData(), property.accessor.constData());
+        fprintf(out, "    return thisPtr->%s->%s.setValue(thisPtr->%s, std::move(value));\n", property.accessor.constData(), property.storage.constData(), property.accessor.constData());
         fprintf(out, "}\n");
 
         // binding setter
@@ -1583,7 +1583,7 @@ void Generator::generateQPropertyApi()
                 property.name.constData(),
                 property.type.name.constData());
         printAccessor();
-        fprintf(out, "    return thisPtr->%s->%s.setBinding(thisPtr->%s, binding);\n", property.accessor.constData(), property.name.constData(), property.accessor.constData());
+        fprintf(out, "    return thisPtr->%s->%s.setBinding(thisPtr->%s, binding);\n", property.accessor.constData(), property.storage.constData(), property.accessor.constData());
         fprintf(out, "}\n");
 
         // binding move setter
@@ -1593,7 +1593,7 @@ void Generator::generateQPropertyApi()
                 property.name.constData(),
                 property.type.name.constData());
         printAccessor();
-        fprintf(out, "    return thisPtr->%s->%s.setBinding(thisPtr->%s, std::move(binding));\n", property.accessor.constData(), property.name.constData(), property.accessor.constData());
+        fprintf(out, "    return thisPtr->%s->%s.setBinding(thisPtr->%s, std::move(binding));\n", property.accessor.constData(), property.storage.constData(), property.accessor.constData());
         fprintf(out, "}\n");
 
         // untyped binding setter
@@ -1601,7 +1601,7 @@ void Generator::generateQPropertyApi()
                 cdef->qualified.constData(),
                 property.name.constData());
         printAccessor();
-        fprintf(out, "    return thisPtr->%s->%s.setBinding(thisPtr->%s, binding);\n", property.accessor.constData(), property.name.constData(), property.accessor.constData());
+        fprintf(out, "    return thisPtr->%s->%s.setBinding(thisPtr->%s, binding);\n", property.accessor.constData(), property.storage.constData(), property.accessor.constData());
         fprintf(out, "}\n");
 
         // binding bool getter
@@ -1609,7 +1609,7 @@ void Generator::generateQPropertyApi()
                 cdef->qualified.constData(),
                 property.name.constData());
         printAccessor(/*const*/true);
-        fprintf(out, "    return thisPtr->%s->%s.hasBinding();\n", property.accessor.constData(), property.name.constData());
+        fprintf(out, "    return thisPtr->%s->%s.hasBinding();\n", property.accessor.constData(), property.storage.constData());
         fprintf(out, "}\n");
 
         // binding getter
@@ -1618,7 +1618,7 @@ void Generator::generateQPropertyApi()
                 cdef->qualified.constData(),
                 property.name.constData());
         printAccessor(/*const*/true);
-        fprintf(out, "    return thisPtr->%s->%s.binding();\n", property.accessor.constData(), property.name.constData());
+        fprintf(out, "    return thisPtr->%s->%s.binding();\n", property.accessor.constData(), property.storage.constData());
         fprintf(out, "}\n");
 
         // binding taker
@@ -1627,7 +1627,7 @@ void Generator::generateQPropertyApi()
                 cdef->qualified.constData(),
                 property.name.constData());
         printAccessor();
-        fprintf(out, "    return thisPtr->%s->%s.takeBinding();\n", property.accessor.constData(), property.name.constData());
+        fprintf(out, "    return thisPtr->%s->%s.takeBinding();\n", property.accessor.constData(), property.storage.constData());
         fprintf(out, "}\n");
 
         // property setter function
diff --git a/src/tools/moc/moc.cpp b/src/tools/moc/moc.cpp
index e31bdfbb15..44e669a664 100644
--- a/src/tools/moc/moc.cpp
+++ b/src/tools/moc/moc.cpp
@@ -1527,14 +1527,9 @@ void Moc::parsePrivateQProperty(ClassDef *def)
     next(IDENTIFIER);
     const QByteArray setter = lexem();
 
-    def->privateQProperties += PrivateQPropertyDef{type, name, setter, accessor};
-
     PropertyDef propDef;
     propDef.name = name;
-    propDef.qpropertyname = name;
     propDef.type = type.name;
-    propDef.read = name + ".value";
-    propDef.write = name + ".setValue";
     propDef.isQProperty = true;
     propDef.isQPropertyWithNotifier = true;
     propDef.inPrivateClass = accessor;
@@ -1544,6 +1539,17 @@ void Moc::parsePrivateQProperty(ClassDef *def)
     if (test(COMMA))
         parsePropertyAttributes(propDef);
 
+    propDef.qpropertyname = (propDef.stored == "true") ? name : (name + "()");
+
+    def->privateQProperties += PrivateQPropertyDef {
+            type, name, setter, accessor, propDef.qpropertyname
+    };
+
+    if (propDef.read.isEmpty())
+        propDef.read = propDef.qpropertyname + ".value";
+    if (propDef.write.isEmpty())
+        propDef.write = propDef.qpropertyname + ".setValue";
+
     next(RPAREN);
 
     def->propertyList += propDef;
diff --git a/src/tools/moc/moc.h b/src/tools/moc/moc.h
index 549b3cdd39..b4bb105601 100644
--- a/src/tools/moc/moc.h
+++ b/src/tools/moc/moc.h
@@ -155,6 +155,7 @@ struct PrivateQPropertyDef
     QByteArray name;
     QByteArray setter;
     QByteArray accessor;
+    QByteArray storage;
 };
 Q_DECLARE_TYPEINFO(PrivateQPropertyDef, Q_MOVABLE_TYPE);
 
diff --git a/tests/auto/tools/moc/tst_moc.cpp b/tests/auto/tools/moc/tst_moc.cpp
index 01d207b080..14c61d552d 100644
--- a/tests/auto/tools/moc/tst_moc.cpp
+++ b/tests/auto/tools/moc/tst_moc.cpp
@@ -4170,13 +4170,17 @@ class ClassWithPrivateQPropertyShim :public QObject
     Q_OBJECT
 public:
     Q_PRIVATE_QPROPERTY(d_func(), int, testProperty, setTestProperty, NOTIFY testPropertyChanged)
+    Q_PRIVATE_QPROPERTY(d_func(), int, lazyTestProperty, setLazyTestProperty,
+                        NOTIFY lazyTestPropertyChanged STORED false)
 
     Q_PRIVATE_QPROPERTIES_BEGIN
     Q_PRIVATE_QPROPERTY_IMPL(testProperty)
+    Q_PRIVATE_QPROPERTY_IMPL(lazyTestProperty)
     Q_PRIVATE_QPROPERTIES_END
 
 signals:
     void testPropertyChanged();
+    void lazyTestPropertyChanged();
 public:
 
     struct Private {
@@ -4188,6 +4192,22 @@ public:
 
         void onTestPropertyChanged() { q->testPropertyChanged(); }
         QNotifiedProperty<int, &Private::onTestPropertyChanged> testProperty;
+
+        void onLazyTestPropertyChanged() { q->lazyTestPropertyChanged(); }
+
+        QNotifiedProperty<int, &Private::onLazyTestPropertyChanged> &lazyTestProperty() {
+            if (!lazyTestPropertyStorage)
+                lazyTestPropertyStorage.reset(new QNotifiedProperty<int, &Private::onLazyTestPropertyChanged>);
+            return *lazyTestPropertyStorage;
+        }
+
+        const QNotifiedProperty<int, &Private::onLazyTestPropertyChanged> &lazyTestProperty() const {
+            if (!lazyTestPropertyStorage)
+                lazyTestPropertyStorage.reset(new QNotifiedProperty<int, &Private::onLazyTestPropertyChanged>);
+            return *lazyTestPropertyStorage;
+        }
+
+        mutable QScopedPointer<QNotifiedProperty<int, &Private::onLazyTestPropertyChanged>> lazyTestPropertyStorage;
     };
     Private priv{this};
 
@@ -4220,6 +4240,24 @@ void tst_Moc::privateQPropertyShim()
     testObject.setTestProperty(400);
     QVERIFY(!testObject.testProperty.hasBinding());
     QCOMPARE(testObject.testProperty(), 400);
+
+    // Created and default-initialized, without nullptr access
+    QCOMPARE(testObject.lazyTestProperty(), 0);
+
+    // Explicitly set to something
+    testObject.priv.lazyTestProperty().setValue(&testObject.priv, 42);
+    QCOMPARE(testObject.property("lazyTestProperty").toInt(), 42);
+
+    // Behave like a QProperty
+    QVERIFY(!testObject.lazyTestProperty.hasBinding());
+    testObject.lazyTestProperty.setBinding([]() { return 100; });
+    QCOMPARE(testObject.lazyTestProperty.value(), 100);
+    QVERIFY(testObject.lazyTestProperty.hasBinding());
+
+    // Old style setter getters
+    testObject.setLazyTestProperty(400);
+    QVERIFY(!testObject.lazyTestProperty.hasBinding());
+    QCOMPARE(testObject.lazyTestProperty(), 400);
 }
 
 QTEST_MAIN(tst_Moc)