add macOS implementation

macos/include/backend/Handle.h

@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef TNT_FILAMENT_BACKEND_HANDLE_H
+#define TNT_FILAMENT_BACKEND_HANDLE_H
+
+#include <utils/compiler.h>
+#if !defined(NDEBUG)
+#include <utils/Log.h>
+#endif
+#include <utils/debug.h>
+
+#include <stdint.h>
+
+#include <limits>
+#include <type_traits>
+
+namespace filament::backend {
+
+struct HwBufferObject;
+struct HwFence;
+struct HwIndexBuffer;
+struct HwProgram;
+struct HwRenderPrimitive;
+struct HwRenderTarget;
+struct HwSamplerGroup;
+struct HwStream;
+struct HwSwapChain;
+struct HwTexture;
+struct HwTimerQuery;
+struct HwVertexBuffer;
+
+/*
+ * A handle to a backend resource. HandleBase is for internal use only.
+ * HandleBase *must* be a trivial for the purposes of calls, that is, it cannot have user-defined
+ * copy or move constructors.
+ */
+
+//! \privatesection
+
+class HandleBase {
+public:
+    using HandleId = uint32_t;
+    static constexpr const HandleId nullid = HandleId{ std::numeric_limits<HandleId>::max() };
+
+    constexpr HandleBase() noexcept: object(nullid) {}
+
+    // whether this Handle is initialized
+    explicit operator bool() const noexcept { return object != nullid; }
+
+    // clear the handle, this doesn't free associated resources
+    void clear() noexcept { object = nullid; }
+
+    // compare handles
+    bool operator==(const HandleBase& rhs) const noexcept { return object == rhs.object; }
+    bool operator!=(const HandleBase& rhs) const noexcept { return object != rhs.object; }
+    bool operator<(const HandleBase& rhs) const noexcept { return object < rhs.object; }
+    bool operator<=(const HandleBase& rhs) const noexcept { return object <= rhs.object; }
+    bool operator>(const HandleBase& rhs) const noexcept { return object > rhs.object; }
+    bool operator>=(const HandleBase& rhs) const noexcept { return object >= rhs.object; }
+
+    // get this handle's handleId
+    HandleId getId() const noexcept { return object; }
+
+    // initialize a handle, for internal use only.
+    explicit HandleBase(HandleId id) noexcept : object(id) {
+        assert_invariant(object != nullid); // usually means an uninitialized handle is used
+    }
+
+protected:
+    HandleBase(HandleBase const& rhs) noexcept = default;
+    HandleBase& operator=(HandleBase const& rhs) noexcept = default;
+
+private:
+    HandleId object;
+};
+
+/**
+ * Type-safe handle to backend resources
+ * @tparam T Type of the resource
+ */
+template<typename T>
+struct Handle : public HandleBase {
+
+    Handle() noexcept = default;
+
+    Handle(Handle const& rhs) noexcept = default;
+
+    Handle& operator=(Handle const& rhs) noexcept = default;
+
+    explicit Handle(HandleId id) noexcept : HandleBase(id) { }
+
+    // type-safe Handle cast
+    template<typename B, typename = std::enable_if_t<std::is_base_of<T, B>::value> >
+    Handle(Handle<B> const& base) noexcept : HandleBase(base) { } // NOLINT(hicpp-explicit-conversions,google-explicit-constructor)
+
+private:
+#if !defined(NDEBUG)
+    template <typename U>
+    friend utils::io::ostream& operator<<(utils::io::ostream& out, const Handle<U>& h) noexcept;
+#endif
+};
+
+// Types used by the command stream
+// (we use this renaming because the macro-system doesn't deal well with "<" and ">")
+using BufferObjectHandle    = Handle<HwBufferObject>;
+using FenceHandle           = Handle<HwFence>;
+using IndexBufferHandle     = Handle<HwIndexBuffer>;
+using ProgramHandle         = Handle<HwProgram>;
+using RenderPrimitiveHandle = Handle<HwRenderPrimitive>;
+using RenderTargetHandle    = Handle<HwRenderTarget>;
+using SamplerGroupHandle    = Handle<HwSamplerGroup>;
+using StreamHandle          = Handle<HwStream>;
+using SwapChainHandle       = Handle<HwSwapChain>;
+using TextureHandle         = Handle<HwTexture>;
+using TimerQueryHandle      = Handle<HwTimerQuery>;
+using VertexBufferHandle    = Handle<HwVertexBuffer>;
+
+} // namespace filament::backend
+
+#endif // TNT_FILAMENT_BACKEND_HANDLE_H