Improve dcast

* document `dcast`
* make `dcast` not only cast exact, but also upwards
* add `dcast` test
* rename `dcast` -> `dynamicCast`

include/AutomatableModel.h

@@ -92,18 +92,25 @@ public:
 	virtual void accept(ConstModelVisitor& v) const = 0;
 
 public:
-	//! Return this class casted to Target, or nullptr if impossible
+	/**
+	   @brief Return this class casted to Target
+	   @test AutomatableModelTest.cpp
+	   @param doThrow throw an assertion if the cast fails, instead of
+	     returning a nullptr
+	   @return the casted class if Target is the exact or a base class of
+	     *this, nullptr otherwise
+	*/
 	template<class Target>
-	Target* dcast(bool doThrow = false)
+	Target* dynamicCast(bool doThrow = false)
 	{
 		DCastVisitor<Target> vis; accept(vis);
 		if(doThrow && !vis.result) Q_ASSERT(false);
 		return vis.result;
 	}
 
-	//! Return this class casted to const Target, or nullptr if impossible
+	//! const overload, see overloaded function
 	template<class Target>
-	const Target* dcast(bool doThrow = false) const
+	const Target* dynamicCast(bool doThrow = false) const
 	{
 		ConstDCastVisitor<Target> vis; accept(vis);
 		if(doThrow && !vis.result) Q_ASSERT(false);
@@ -312,6 +319,7 @@ protected:
 
 
 private:
+	// dynamicCast implementation
 	template<class Target>
 	struct DCastVisitor : public ModelVisitor
 	{
@@ -319,6 +327,7 @@ private:
 		void visit(Target& tar) { result = &tar; }
 	};
 
+	// dynamicCast implementation
 	template<class Target>
 	struct ConstDCastVisitor : public ConstModelVisitor
 	{

include/ModelVisitor.h

@@ -25,6 +25,7 @@
 #ifndef MODELVISITOR_H
 #define MODELVISITOR_H
 
+class AutomatableModel;
 class BoolModel;
 class IntModel;
 class FloatModel;
@@ -32,21 +33,28 @@ class ComboBoxModel;
 
 class ModelVisitor
 {
+	template<class ParentType = AutomatableModel, class ModelType>
+	void up(ModelType& m) { visit(static_cast<ParentType&>(m)); }
 public:
-	virtual void visit(BoolModel& ) {}
-	virtual void visit(IntModel& ) {}
-	virtual void visit(FloatModel& ) {}
-	virtual void visit(ComboBoxModel& ) {}
+	virtual void visit(AutomatableModel& ) {}
+	virtual void visit(BoolModel& m);
+	virtual void visit(IntModel& );
+	virtual void visit(FloatModel& );
+	virtual void visit(ComboBoxModel& );
 	virtual ~ModelVisitor();
 };
 
 class ConstModelVisitor
 {
+	template<class ParentType = AutomatableModel, class ModelType>
+	void up(const ModelType& m) {
+		visit(static_cast<const ParentType&>(m)); }
 public:
-	virtual void visit(const BoolModel& ) {}
-	virtual void visit(const IntModel& ) {}
-	virtual void visit(const FloatModel& ) {}
-	virtual void visit(const ComboBoxModel& ) {}
+	virtual void visit(const AutomatableModel& ) {}
+	virtual void visit(const BoolModel& m);
+	virtual void visit(const IntModel& m);
+	virtual void visit(const FloatModel& m);
+	virtual void visit(const ComboBoxModel& m);
 	virtual ~ConstModelVisitor();
 };
 

src/core/ModelVisitor.cpp

@@ -24,5 +24,18 @@
 
 #include "ModelVisitor.h"
 
+#include "AutomatableModel.h"
+#include "ComboBoxModel.h"
+
+void ModelVisitor::visit(BoolModel &m) { up(m); }
+void ModelVisitor::visit(IntModel &m) { up(m); }
+void ModelVisitor::visit(FloatModel &m) { up(m); }
+void ModelVisitor::visit(ComboBoxModel &m) { up<IntModel>(m); }
+
+void ConstModelVisitor::visit(const BoolModel &m) { up(m); }
+void ConstModelVisitor::visit(const IntModel &m) { up(m); }
+void ConstModelVisitor::visit(const FloatModel &m) { up(m); }
+void ConstModelVisitor::visit(const ComboBoxModel &m) { up<IntModel>(m); }
+
 ModelVisitor::~ModelVisitor() {}
 ConstModelVisitor::~ConstModelVisitor() {}

tests/CMakeLists.txt

@@ -14,6 +14,7 @@ ADD_EXECUTABLE(tests
 	QTestSuite
 	$<TARGET_OBJECTS:lmmsobjs>
 
+	src/core/AutomatableModelTest.cpp
 	src/core/ProjectVersionTest.cpp
 	src/core/RelativePathsTest.cpp
 

tests/src/core/AutomatableModelTest.cpp

@@ -0,0 +1,53 @@
+/*
+ * AutomatableModelTest.cpp
+ *
+ * Copyright (c) 2019-2019 Johannes Lorenz <j.git$$$lorenz-ho.me, $$$=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "QTestSuite.h"
+
+#include "AutomatableModel.h"
+#include "ComboBoxModel.h"
+
+class AutomatableModelTest : QTestSuite
+{
+	Q_OBJECT
+
+private slots:
+	void CastTests()
+	{
+		ComboBoxModel comboModel;
+		AutomatableModel* amPtr = &comboModel;
+		QCOMPARE(nullptr, amPtr->dynamicCast<FloatModel>());
+		QVERIFY(nullptr != amPtr->dynamicCast<AutomatableModel>());
+		QVERIFY(nullptr != amPtr->dynamicCast<IntModel>());
+		QVERIFY(nullptr != amPtr->dynamicCast<ComboBoxModel>());
+
+		IntModel intModel;
+		IntModel* imPtr = &intModel;
+		QCOMPARE(nullptr, imPtr->dynamicCast<FloatModel>());
+		QVERIFY(nullptr != imPtr->dynamicCast<AutomatableModel>());
+		QVERIFY(nullptr != imPtr->dynamicCast<IntModel>());
+		QCOMPARE(nullptr, imPtr->dynamicCast<ComboBoxModel>());
+	}
+} AutomatableModelTests;
+
+#include "AutomatableModelTest.moc"