move core result into core utils

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/utils/result/debug_inspect.rs

@@ -0,0 +1,52 @@
+use super::Result;
+
+/// Inspect Result values with release-mode elision.
+pub trait DebugInspect<T, E> {
+	/// Inspects an Err contained value in debug-mode. In release-mode closure F
+	/// is elided.
+	#[must_use]
+	fn debug_inspect_err<F: FnOnce(&E)>(self, f: F) -> Self;
+
+	/// Inspects an Ok contained value in debug-mode. In release-mode closure F
+	/// is elided.
+	#[must_use]
+	fn debug_inspect<F: FnOnce(&T)>(self, f: F) -> Self;
+}
+
+#[cfg(debug_assertions)]
+impl<T, E> DebugInspect<T, E> for Result<T, E> {
+	#[inline]
+	fn debug_inspect<F>(self, f: F) -> Self
+	where
+		F: FnOnce(&T),
+	{
+		self.inspect(f)
+	}
+
+	#[inline]
+	fn debug_inspect_err<F>(self, f: F) -> Self
+	where
+		F: FnOnce(&E),
+	{
+		self.inspect_err(f)
+	}
+}
+
+#[cfg(not(debug_assertions))]
+impl<T, E> DebugInspect<T, E> for Result<T, E> {
+	#[inline]
+	fn debug_inspect<F>(self, _: F) -> Self
+	where
+		F: FnOnce(&T),
+	{
+		self
+	}
+
+	#[inline]
+	fn debug_inspect_err<F>(self, _: F) -> Self
+	where
+		F: FnOnce(&E),
+	{
+		self
+	}
+}