Replace convertTo/stringify with non-throwing alternatives.

Having these throw is terrible for ergonomics and there are loads
of places where the exception was either silently ignored or not
handled at all. Having a function which returns an optional and
another that returns a default works a lot better imo.

1 files changed, 133 insertions, 0 deletions

diff --git a/include/convert.h b/include/convert.h
new file mode 100644
index 000000000..3cdbcd787
--- /dev/null
+++ b/include/convert.h
@@ -0,0 +1,133 @@
+/*
+ *
+ * (C) 2003-2024 Anope Team
+ * Contact us at team@anope.org
+ *
+ * Please read COPYING and README for further details.
+ *
+ * Based on the original code of Epona by Lara.
+ * Based on the original code of Services by Andy Church.
+ */
+
+#pragma once
+
+#include <optional>
+
+namespace Anope
+{
+	/** Attempts to convert a string to any type.
+	 * @param in The value to convert.
+	 * @param leftover If non-nullptr then the location to store leftover data.
+	 */
+	template<typename T>
+	inline std::optional<T> TryConvert(const Anope::string &in, Anope::string *leftover = nullptr)
+	{
+		std::istringstream tmp(in.str());
+		T out;
+		if (!(tmp >> out))
+			return std::nullopt;
+
+		if (leftover)
+		{
+			std::string extra;
+			std::getline(tmp, extra);
+			*leftover = extra;
+		}
+		else
+		{
+			char extra;
+			if (tmp >> extra)
+				return std::nullopt;
+		}
+		return out;
+	}
+
+	/** Converts a string to any type.
+	 * @param in The value to convert.
+	 * @param def The default to use if the conversion failed.
+	 * @param leftover If non-nullptr then the location to store leftover data.
+	 */
+	template<typename T>
+	inline T Convert(const Anope::string &in, T def, Anope::string *leftover = nullptr)
+	{
+		return TryConvert<T>(in, leftover).value_or(def);
+	}
+
+	/** Attempts to convert any type to a string.
+	 * @param in The value to convert.
+	 */
+	template <class T>
+	inline std::optional<Anope::string> TryString(const T &in)
+	{
+		std::ostringstream tmp;
+		if (!(tmp << in))
+			return std::nullopt;
+		return tmp.str();
+	}
+
+	/** No-op function that returns the string that was passed to it.
+	 * @param in The string to return.
+	 */
+	inline const string &ToString(const string &in)
+	{
+		return in;
+	}
+
+	/** Converts a std::string to a string.
+	 * @param in The value to convert.
+	 */
+	inline string ToString(const std::string &in)
+	{
+		return in;
+	}
+
+	/** Converts a char array to a string.
+	 * @param in The value to convert.
+	 */
+	inline string ToString(const char *in)
+	{
+		return string(in);
+	}
+
+	/** Converts a char to a string.
+	 * @param in The value to convert.
+	 */
+	inline string ToString(char in)
+	{
+		return string(1, static_cast<string::value_type>(in));
+	}
+
+	/** Converts an unsigned char to a string.
+	 * @param in The value to convert.
+	 */
+	inline string ToString(unsigned char in)
+	{
+		return string(1, static_cast<string::value_type>(in));
+	}
+
+	/** Converts a bool to a string.
+	 * @param in The value to convert.
+	 */
+	inline string ToString(bool in)
+	{
+		return (in ? "1" : "0");
+	}
+
+	/** Converts a type that std::to_string is implemented for to a string.
+	 * @param in The value to convert.
+	 */
+	template<typename Stringable>
+	inline std::enable_if_t<std::is_arithmetic_v<Stringable>, string> ToString(const Stringable &in)
+	{
+		return std::to_string(in);
+	}
+
+	/** Converts any type to a string.
+	 * @param in The value to convert.
+	 */
+	template <class T>
+	inline std::enable_if_t<!std::is_arithmetic_v<T>, string> ToString(const T &in)
+	{
+		return TryString(in).value_or(Anope::string());
+	}
+}