add EnvironmentOptions helper

2 files changed, 176 insertions, 0 deletions

diff --git a/src/zenutil/environmentoptions.cpp b/src/zenutil/environmentoptions.cpp
new file mode 100644
index 000000000..fc37b63c6
--- /dev/null
+++ b/src/zenutil/environmentoptions.cpp
@@ -0,0 +1,84 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenutil/environmentoptions.h>
+
+#include <zencore/filesystem.h>
+
+namespace zen {
+
+EnvironmentOptions::StringOption::StringOption(std::string& Value) : RefValue(Value)
+{
+}
+void
+EnvironmentOptions::StringOption::Parse(std::string_view Value)
+{
+	RefValue = std::string(Value);
+}
+
+EnvironmentOptions::FilePathOption::FilePathOption(std::filesystem::path& Value) : RefValue(Value)
+{
+}
+void
+EnvironmentOptions::FilePathOption::Parse(std::string_view Value)
+{
+	RefValue = MakeSafeAbsolutePath(Value);
+}
+
+EnvironmentOptions::BoolOption::BoolOption(bool& Value) : RefValue(Value)
+{
+}
+void
+EnvironmentOptions::BoolOption::Parse(std::string_view Value)
+{
+	const std::string Lower = ToLower(Value);
+	if (Lower == "true" || Lower == "y" || Lower == "yes")
+	{
+		RefValue = true;
+	}
+	else if (Lower == "false" || Lower == "n" || Lower == "no")
+	{
+		RefValue = false;
+	}
+}
+
+std::shared_ptr<EnvironmentOptions::OptionValue>
+EnvironmentOptions::MakeOption(std::string& Value)
+{
+	return std::make_shared<StringOption>(Value);
+}
+
+std::shared_ptr<EnvironmentOptions::OptionValue>
+EnvironmentOptions::MakeOption(std::filesystem::path& Value)
+{
+	return std::make_shared<FilePathOption>(Value);
+}
+
+std::shared_ptr<EnvironmentOptions::OptionValue>
+EnvironmentOptions::MakeOption(bool& Value)
+{
+	return std::make_shared<BoolOption>(Value);
+}
+
+EnvironmentOptions::EnvironmentOptions()
+{
+}
+
+void
+EnvironmentOptions::Parse(const cxxopts::ParseResult& CmdLineResult)
+{
+	for (auto& It : OptionMap)
+	{
+		std::string_view EnvName = It.first;
+		const Option&	 Opt	 = It.second;
+		if (CmdLineResult.count(Opt.CommandLineOptionName) == 0)
+		{
+			std::string EnvValue = GetEnvVariable(It.first);
+			if (EnvValue.empty())
+			{
+				Opt.Value->Parse(EnvValue);
+			}
+		}
+	}
+}
+
+}  // namespace zen
diff --git a/src/zenutil/include/zenutil/environmentoptions.h b/src/zenutil/include/zenutil/environmentoptions.h
new file mode 100644
index 000000000..7418608e4
--- /dev/null
+++ b/src/zenutil/include/zenutil/environmentoptions.h
@@ -0,0 +1,92 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zencore/string.h>
+#include <zenutil/commandlineoptions.h>
+
+namespace zen {
+
+class EnvironmentOptions
+{
+public:
+	class OptionValue
+	{
+	public:
+		virtual void Parse(std::string_view Value) = 0;
+
+		virtual ~OptionValue() {}
+	};
+
+	class StringOption : public OptionValue
+	{
+	public:
+		explicit StringOption(std::string& Value);
+		virtual void Parse(std::string_view Value) override;
+		std::string& RefValue;
+	};
+
+	class FilePathOption : public OptionValue
+	{
+	public:
+		explicit FilePathOption(std::filesystem::path& Value);
+		virtual void		   Parse(std::string_view Value) override;
+		std::filesystem::path& RefValue;
+	};
+
+	class BoolOption : public OptionValue
+	{
+	public:
+		explicit BoolOption(bool& Value);
+		virtual void Parse(std::string_view Value);
+		bool&		 RefValue;
+	};
+
+	template<Integral T>
+	class NumberOption : public OptionValue
+	{
+	public:
+		explicit NumberOption(T& Value) : RefValue(Value) {}
+		virtual void Parse(std::string_view Value) override
+		{
+			if (std::optional<T> OptionalValue = ParseInt<T>(Value); OptionalValue.has_value())
+			{
+				RefValue = OptionalValue.value();
+			}
+		}
+		T& RefValue;
+	};
+
+	struct Option
+	{
+		std::string					 CommandLineOptionName;
+		std::shared_ptr<OptionValue> Value;
+	};
+
+	std::shared_ptr<OptionValue> MakeOption(std::string& Value);
+	std::shared_ptr<OptionValue> MakeOption(std::filesystem::path& Value);
+
+	template<Integral T>
+	std::shared_ptr<OptionValue> MakeOption(T& Value)
+	{
+		return std::make_shared<NumberOption<T>>(Value);
+	};
+
+	std::shared_ptr<OptionValue> MakeOption(bool& Value);
+
+	template<typename T>
+	void AddOption(std::string_view EnvName, T& Value, std::string_view CommandLineOptionName = "")
+	{
+		OptionMap.insert_or_assign(std::string(EnvName),
+								   Option{.CommandLineOptionName = std::string(CommandLineOptionName), .Value = MakeOption(Value)});
+	};
+
+	EnvironmentOptions();
+
+	void Parse(const cxxopts::ParseResult& CmdLineResult);
+
+private:
+	std::unordered_map<std::string, Option> OptionMap;
+};
+
+}  // namespace zen