video: Import new shader recompiler + display a triangle (#142)

src/shader_recompiler/object_pool.h

@@ -0,0 +1,107 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+namespace Shader {
+
+template <typename T>
+    requires std::is_destructible_v<T>
+class ObjectPool {
+public:
+    explicit ObjectPool(size_t chunk_size = 8192) : new_chunk_size{chunk_size} {
+        node = &chunks.emplace_back(new_chunk_size);
+    }
+
+    template <typename... Args>
+        requires std::is_constructible_v<T, Args...>
+    [[nodiscard]] T* Create(Args&&... args) {
+        return std::construct_at(Memory(), std::forward<Args>(args)...);
+    }
+
+    void ReleaseContents() {
+        if (chunks.empty()) {
+            return;
+        }
+        Chunk& root{chunks.front()};
+        if (root.used_objects == root.num_objects) {
+            // Root chunk has been filled, squash allocations into it
+            const size_t total_objects{root.num_objects + new_chunk_size * (chunks.size() - 1)};
+            chunks.clear();
+            chunks.emplace_back(total_objects);
+        } else {
+            root.Release();
+            chunks.resize(1);
+        }
+        chunks.shrink_to_fit();
+        node = &chunks.front();
+    }
+
+private:
+    struct NonTrivialDummy {
+        NonTrivialDummy() noexcept {}
+    };
+
+    union Storage {
+        Storage() noexcept {}
+        ~Storage() noexcept {}
+
+        NonTrivialDummy dummy{};
+        T object;
+    };
+
+    struct Chunk {
+        explicit Chunk() = default;
+        explicit Chunk(size_t size)
+            : num_objects{size}, storage{std::make_unique<Storage[]>(size)} {}
+
+        Chunk& operator=(Chunk&& rhs) noexcept {
+            Release();
+            used_objects = std::exchange(rhs.used_objects, 0);
+            num_objects = std::exchange(rhs.num_objects, 0);
+            storage = std::move(rhs.storage);
+            return *this;
+        }
+
+        Chunk(Chunk&& rhs) noexcept
+            : used_objects{std::exchange(rhs.used_objects, 0)},
+              num_objects{std::exchange(rhs.num_objects, 0)}, storage{std::move(rhs.storage)} {}
+
+        ~Chunk() {
+            Release();
+        }
+
+        void Release() {
+            std::destroy_n(storage.get(), used_objects);
+            used_objects = 0;
+        }
+
+        size_t used_objects{};
+        size_t num_objects{};
+        std::unique_ptr<Storage[]> storage;
+    };
+
+    [[nodiscard]] T* Memory() {
+        Chunk* const chunk{FreeChunk()};
+        return &chunk->storage[chunk->used_objects++].object;
+    }
+
+    [[nodiscard]] Chunk* FreeChunk() {
+        if (node->used_objects != node->num_objects) {
+            return node;
+        }
+        node = &chunks.emplace_back(new_chunk_size);
+        return node;
+    }
+
+    Chunk* node{};
+    std::vector<Chunk> chunks;
+    size_t new_chunk_size{};
+};
+
+} // namespace Shader