fssrv: skeleton more program registry logic

libraries/libstratosphere/include/stratosphere/fssystem/fssystem_pimpl.hpp

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <vapours.hpp>
+
+namespace ams::fssystem {
+
+    namespace impl {
+
+        template<typename T, size_t Size>
+        struct PimplHelper {
+            static void Construct(void *);
+            static void Destroy(void *);
+        };
+
+    }
+
+    template<typename T, size_t Size>
+    class Pimpl {
+        private:
+            alignas(0x10) u8 m_storage[Size];
+        public:
+            ALWAYS_INLINE Pimpl()  { impl::PimplHelper<T, Size>::Construct(m_storage); }
+            ALWAYS_INLINE ~Pimpl() { impl::PimplHelper<T, Size>::Destroy(m_storage); }
+
+            ALWAYS_INLINE T *Get() { return reinterpret_cast<T *>(m_storage + 0); }
+            ALWAYS_INLINE T *operator->() { return reinterpret_cast<T *>(m_storage + 0); }
+    };
+
+    #define AMS_FSSYSTEM_ENABLE_PIMPL(_CLASSNAME_)                    \
+        namespace ams::fssystem::impl {                               \
+                                                                      \
+            template<size_t Size>                                     \
+            struct PimplHelper<_CLASSNAME_, Size> {                   \
+                static ALWAYS_INLINE void Construct(void *p) {        \
+                    static_assert(sizeof(_CLASSNAME_) <= Size);       \
+                    static_assert(alignof(_CLASSNAME_) <= 0x10);      \
+                                                                      \
+                    std::construct_at(static_cast<_CLASSNAME_ *>(p)); \
+                }                                                     \
+                                                                      \
+                static ALWAYS_INLINE void Destroy(void *p) {          \
+                    std::destroy_at(static_cast<_CLASSNAME_ *>(p));   \
+                }                                                     \
+            };                                                        \
+                                                                      \
+        }
+
+}