The d-pointer design patterns helps creating public classes that can be extended without breaking their ABI. To facilitate usage of the pattern in libcamera, create a base Extensible class with associated macros. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
88 lines
1.4 KiB
C++
88 lines
1.4 KiB
C++
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/*
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* Copyright (C) 2020, Google Inc.
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*
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* extensible.h - Utilities to create extensible public classes with stable ABIs
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*/
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#ifndef __LIBCAMERA_EXTENSIBLE_H__
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#define __LIBCAMERA_EXTENSIBLE_H__
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#include <memory>
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namespace libcamera {
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#ifndef __DOXYGEN__
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#define LIBCAMERA_DECLARE_PRIVATE(klass) \
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public: \
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class Private; \
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friend class Private;
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#define LIBCAMERA_DECLARE_PUBLIC(klass) \
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friend class klass; \
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using Public = klass;
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#define LIBCAMERA_D_PTR() \
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_d<Private>();
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#define LIBCAMERA_O_PTR() \
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_o<Public>();
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#else
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#define LIBCAMERA_DECLARE_PRIVATE(klass)
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#define LIBCAMERA_DECLARE_PUBLIC(klass)
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#define LIBCAMERA_D_PTR(klass)
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#define LIBCAMERA_O_PTR(klass)
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#endif
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class Extensible
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{
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public:
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class Private
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{
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public:
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Private(Extensible *o);
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virtual ~Private();
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#ifndef __DOXYGEN__
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template<typename T>
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const T *_o() const
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{
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return static_cast<const T *>(o_);
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}
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template<typename T>
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T *_o()
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{
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return static_cast<T *>(o_);
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}
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#endif
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private:
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Extensible *const o_;
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};
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Extensible(Private *d);
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protected:
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#ifndef __DOXYGEN__
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template<typename T>
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const T *_d() const
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{
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return static_cast<const T *>(d_.get());
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}
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template<typename T>
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T *_d()
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{
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return static_cast<T *>(d_.get());
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}
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#endif
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private:
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const std::unique_ptr<Private> d_;
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};
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} /* namespace libcamera */
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#endif /* __LIBCAMERA_EXTENSIBLE_H__ */
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