libcamera: class: Provide move and copy disablers

It can be difficult to correctly parse the syntax for copy/move and the
associated assignment operators.

Provide helpers as syntactic sugar to facilitate disabling either the
copy constructor, and copy assignment operator, and the move constructor
and move assignment operator in a way which is explicit and clear.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/libcamera/class.h

@@ -11,6 +11,24 @@
 
 namespace libcamera {
 
+#ifndef __DOXYGEN__
+#define LIBCAMERA_DISABLE_COPY(klass)  \
+	klass(const klass &) = delete; \
+	klass &operator=(const klass &) = delete;
+
+#define LIBCAMERA_DISABLE_MOVE(klass) \
+	klass(klass &&) = delete;     \
+	klass &operator=(klass &&) = delete;
+
+#define LIBCAMERA_DISABLE_COPY_AND_MOVE(klass) \
+	LIBCAMERA_DISABLE_COPY(klass)          \
+	LIBCAMERA_DISABLE_MOVE(klass)
+#else
+#define LIBCAMERA_DISABLE_COPY(klass)
+#define LIBCAMERA_DISABLE_MOVE(klass)
+#define LIBCAMERA_DISABLE_COPY_AND_MOVE(klass)
+#endif
+
 #ifndef __DOXYGEN__
 #define LIBCAMERA_DECLARE_PRIVATE(klass)				\
 public:									\

src/libcamera/class.cpp

@@ -17,6 +17,63 @@
 
 namespace libcamera {
 
+/**
+ * \def LIBCAMERA_DISABLE_COPY
+ * \brief Disable copy construction and assignment of the \a klass
+ * \param klass The name of the class
+ *
+ * Example usage:
+ * \code{.cpp}
+ * class NonCopyable
+ * {
+ * public:
+ * 	NonCopyable();
+ * 	...
+ *
+ * private:
+ * 	LIBCAMERA_DISABLE_COPY(NonCopyable)
+ * };
+ * \endcode
+ */
+
+/**
+ * \def LIBCAMERA_DISABLE_MOVE
+ * \brief Disable move construction and assignment of the \a klass
+ * \param klass The name of the class
+ *
+ * Example usage:
+ * \code{.cpp}
+ * class NonMoveable
+ * {
+ * public:
+ * 	NonMoveable();
+ * 	...
+ *
+ * private:
+ * 	LIBCAMERA_DISABLE_MOVE(NonMoveable)
+ * };
+ * \endcode
+ */
+
+/**
+ * \def LIBCAMERA_DISABLE_COPY_AND_MOVE
+ * \brief Disable copy and move construction and assignment of the \a klass
+ * \param klass The name of the class
+ *
+ * Example usage:
+ * \code{.cpp}
+ * class NonCopyableNonMoveable
+ * {
+ * public:
+ * 	NonCopyableNonMoveable();
+ * 	...
+ *
+ * private:
+ * 	LIBCAMERA_DISABLE_COPY_AND_MOVE(NonCopyableNonMoveable)
+ * };
+ * \endcode
+ */
+
 /**
  * \def LIBCAMERA_DECLARE_PRIVATE
  * \brief Declare private data for a public class