Cleanup related fixes

Signed-off-by: falkTX <falktx@falktx.com>

src/extra/ScopedValueSetter.hpp

@@ -0,0 +1,90 @@
+/*
+ * Scope value setter, taken from JUCE v4
+ * Copyright (C) 2013 Raw Material Software Ltd.
+ * Copyright (c) 2016 ROLI Ltd.
+ * Copyright (C) 2013-2020 Filipe Coelho <falktx@falktx.com>
+ *
+ * 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 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.
+ *
+ * For a full copy of the GNU General Public License see the doc/GPL.txt file.
+ */
+
+#pragma once
+
+#include "DistrhoUtils.hpp"
+
+START_NAMESPACE_DISTRHO
+
+//=====================================================================================================================
+/**
+    Helper class providing an RAII-based mechanism for temporarily setting and
+    then re-setting a value.
+
+    E.g. @code
+    int x = 1;
+
+    {
+        ScopedValueSetter setter (x, 2);
+
+        // x is now 2
+    }
+
+    // x is now 1 again
+
+    {
+        ScopedValueSetter setter (x, 3, 4);
+
+        // x is now 3
+    }
+
+    // x is now 4
+    @endcode
+*/
+template <typename ValueType>
+class ScopedValueSetter
+{
+public:
+    /** Creates a ScopedValueSetter that will immediately change the specified value to the
+        given new value, and will then reset it to its original value when this object is deleted.
+        Must be used only for 'noexcept' compatible types.
+    */
+    ScopedValueSetter(ValueType& valueToSet, ValueType newValue) noexcept
+        : value(valueToSet),
+          originalValue(valueToSet)
+    {
+        valueToSet = newValue;
+    }
+
+    /** Creates a ScopedValueSetter that will immediately change the specified value to the
+        given new value, and will then reset it to be valueWhenDeleted when this object is deleted.
+    */
+    ScopedValueSetter(ValueType& valueToSet, ValueType newValue, ValueType valueWhenDeleted) noexcept
+        : value(valueToSet),
+          originalValue(valueWhenDeleted)
+    {
+        valueToSet = newValue;
+    }
+
+    ~ScopedValueSetter() noexcept
+    {
+        value = originalValue;
+    }
+
+private:
+    //=================================================================================================================
+    ValueType& value;
+    const ValueType originalValue;
+
+    DISTRHO_DECLARE_NON_COPYABLE(ScopedValueSetter)
+    DISTRHO_PREVENT_HEAP_ALLOCATION
+};
+
+END_NAMESPACE_DISTRHO