Merge pull request #33 from CapsCollective/feature/defer-utils

Implemented scoped defer utility

Author: jonjondev

engine/render/renderer/platform/vulkan/Texture2D.cpp

@@ -15,6 +15,7 @@
 
 #define STB_IMAGE_IMPLEMENTATION
 #include <stb_image.h>
+#include <utils/Defer.h>
 #include <utils/Logging.h>
 
 namespace Siege::Vulkan
@@ -73,6 +74,7 @@ void Texture2D::LoadFromFile(const char* filePath)
     uint64_t imageSize = texWidth * texHeight * 4;
 
     uint8_t* pixelPtr = new uint8_t[imageSize];
+    defer([pixelPtr] { delete[] pixelPtr; });
 
     // Set the image to 0 so that we get no garbage data in the pixel array
     memset(pixelPtr, 0, imageSize);
@@ -102,8 +104,6 @@ void Texture2D::LoadFromFile(const char* filePath)
     image.CopyBuffer(stagingBuffer.buffer);
 
     Buffer::DestroyBuffer(stagingBuffer);
-
-    delete[] pixelPtr;
 }
 
 void Texture2D::LoadTexture(const uint8_t* pixels, size_t size, uint32_t width, uint32_t height)

engine/utils/Defer.h

@@ -0,0 +1,54 @@
+//
+// Copyright (c) 2023 Jonathan Moallem (@J-Mo63) & Aryeh Zinn (@Raelr)
+//
+// This code is released under an unmodified zlib license.
+// For conditions of distribution and use, please see:
+//     https://opensource.org/licenses/Zlib
+//
+
+#ifndef SIEGE_ENGINE_DEFER_H
+#define SIEGE_ENGINE_DEFER_H
+
+#include <functional>
+
+#include "Macros.h"
+
+namespace Siege
+{
+
+/**
+ * A basic deferred call object implementation that executes its provided callable on scope exit.
+ */
+struct ScopedDefer
+{
+    /**
+     * Explicitly deleted zero-param constructor
+     */
+    ScopedDefer() = delete;
+
+    /**
+     * Constructor, specifying owned callable
+     * @param callable - the void-returning, parameterless callable to execute
+     */
+    explicit ScopedDefer(const std::function<void()>& callable) : callable(callable) {}
+
+    /**
+     * Destructor, executing callable on scope exit
+     */
+    ~ScopedDefer()
+    {
+        callable();
+    }
+
+    /**
+     * Held void-retuning, parameterless callable
+     */
+    std::function<void()> callable;
+};
+
+#define _DEFER_VAR_NAME CONCAT_SYMBOL(_defer_, __COUNTER__)
+#define defer(callable) auto _DEFER_VAR_NAME = Siege::ScopedDefer(callable)
+
+} // namespace Siege
+
+#endif // SIEGE_ENGINE_DEFER_H

tests/utils/test_Defer.cpp

@@ -0,0 +1,49 @@
+//
+// Copyright (c) 2022 Jonathan Moallem (@J-Mo63) & Aryeh Zinn (@Raelr)
+//
+// This code is released under an unmodified zlib license.
+// For conditions of distribution and use, please see:
+//     https://opensource.org/licenses/Zlib
+//
+
+#include <utest.h>
+#include <utils/Defer.h>
+
+UTEST(test_Defer, BasicScopeDeferModify)
+{
+    bool a = true;
+    {
+        ASSERT_TRUE(a);
+        defer([&a] { a = false; });
+        a = true;
+        ASSERT_TRUE(a);
+    }
+    ASSERT_FALSE(a);
+}
+
+UTEST(test_Defer, BasicScopeDeferDeletion)
+{
+    auto* a = new bool;
+    {
+        ASSERT_TRUE(a);
+        defer([&a] {
+            delete a;
+            a = nullptr;
+        });
+        ASSERT_TRUE(a);
+    }
+    ASSERT_FALSE(a);
+}
+
+UTEST(test_Defer, LoopScopeDeferModify)
+{
+    bool a = true;
+    for (uint8_t i = 0; i < 3; ++i)
+    {
+        ASSERT_TRUE(a);
+        defer([&a] { a = true; });
+        a = false;
+        ASSERT_FALSE(a);
+    }
+    ASSERT_TRUE(a);
+}