Core: Rework VirtualDirectory to allow custom directory resolving

src/Nazara/Core/AppFilesystemComponent.cpp

@@ -3,8 +3,32 @@
 // For conditions of distribution and use, see copyright notice in Config.hpp
 
 #include <Nazara/Core/AppFilesystemComponent.hpp>
+#include <Nazara/Core/VirtualDirectoryFilesystemResolver.hpp>
 #include <Nazara/Core/Debug.hpp>
 
 namespace Nz
 {
+	const VirtualDirectoryPtr& AppFilesystemComponent::Mount(std::string_view name, std::filesystem::path filepath)
+	{
+		return Mount(name, std::make_shared<VirtualDirectory>(std::make_shared<VirtualDirectoryFilesystemResolver>(std::move(filepath))));
+	}
+
+	const VirtualDirectoryPtr& AppFilesystemComponent::Mount(std::string_view name, VirtualDirectoryPtr directory)
+	{
+		if (name.empty())
+		{
+			m_rootDirectory = std::move(directory);
+			return m_rootDirectory;
+		}
+
+		if (!m_rootDirectory)
+			m_rootDirectory = std::make_shared<VirtualDirectory>();
+
+		return m_rootDirectory->StoreDirectory(name, std::move(directory)).directory;
+	}
+
+	void AppFilesystemComponent::MountDefaultDirectories()
+	{
+		m_rootDirectory = std::make_shared<VirtualDirectory>(std::make_shared<VirtualDirectoryFilesystemResolver>(std::filesystem::current_path()));
+	}
 }

src/Nazara/Core/VirtualDirectory.cpp

@@ -0,0 +1,11 @@
+// Copyright (C) 2023 Jérôme "Lynix" Leclercq (lynix680@gmail.com)
+// This file is part of the "Nazara Engine - Core module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Core/VirtualDirectory.hpp>
+#include <Nazara/Core/Debug.hpp>
+
+namespace Nz
+{
+	VirtualDirectoryResolver::~VirtualDirectoryResolver() = default;
+}

src/Nazara/Core/VirtualDirectoryFilesystemResolver.cpp

@@ -0,0 +1,53 @@
+// Copyright (C) 2023 Jérôme "Lynix" Leclercq (lynix680@gmail.com)
+// This file is part of the "Nazara Engine - Core module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Core/VirtualDirectoryFilesystemResolver.hpp>
+#include <Nazara/Utils/Algorithm.hpp>
+#include <Nazara/Core/Debug.hpp>
+
+namespace Nz
+{
+	void VirtualDirectoryFilesystemResolver::ForEach(std::weak_ptr<VirtualDirectory> parent, FunctionRef<bool(std::string_view name, VirtualDirectory::Entry&& entry)> callback) const
+	{
+		for (auto&& physicalEntry : std::filesystem::directory_iterator(m_physicalPath))
+		{
+			std::string filename = PathToString(physicalEntry.path().filename());
+
+			std::filesystem::file_status status = physicalEntry.status();
+
+			VirtualDirectory::Entry entry;
+			if (std::filesystem::is_regular_file(status))
+			{
+				if (!callback(filename, VirtualDirectory::FileEntry{ std::make_shared<File>(physicalEntry.path(), m_fileOpenMode) }))
+					return;
+			}
+			else if (std::filesystem::is_directory(status))
+			{
+				VirtualDirectoryPtr virtualDir = std::make_shared<VirtualDirectory>(std::make_shared<VirtualDirectoryFilesystemResolver>(physicalEntry.path()), parent);
+				if (!callback(filename, VirtualDirectory::DirectoryEntry{ { std::move(virtualDir) } }))
+					return;
+			}
+		}
+	}
+
+	std::optional<VirtualDirectory::Entry> VirtualDirectoryFilesystemResolver::Resolve(std::weak_ptr<VirtualDirectory> parent, const std::string_view* parts, std::size_t partCount) const
+	{
+		std::filesystem::path filePath = m_physicalPath;
+		for (std::size_t i = 0; i < partCount; ++i)
+			filePath /= parts[i];
+
+		std::filesystem::file_status status = std::filesystem::status(filePath); //< FIXME: This will follow symlink, is this the intended behavior? (see symlink_status)
+
+		VirtualDirectory::Entry entry;
+		if (std::filesystem::is_regular_file(status))
+			return VirtualDirectory::FileEntry{ std::make_shared<File>(std::move(filePath), m_fileOpenMode) };
+		else if (std::filesystem::is_directory(status))
+		{
+			VirtualDirectoryPtr virtualDir = std::make_shared<VirtualDirectory>(std::make_shared<VirtualDirectoryFilesystemResolver>(std::move(filePath)), parent);
+			return VirtualDirectory::DirectoryEntry{ { std::move(virtualDir) } };
+		}
+		else
+			return std::nullopt; //< either not known or of a special type
+	}
+}