runner: add Steal wrapper, use for socket

A deref wrapper that allows taking out its contents, which is convenient
after a fork.

1 files changed, 40 insertions, 0 deletions

diff --git a/crates/runner/src/util/steal.rs b/crates/runner/src/util/steal.rs
new file mode 100644
index 0000000..91b2cdf
--- /dev/null
+++ b/crates/runner/src/util/steal.rs
@@ -0,0 +1,40 @@
+use std::ops::{Deref, DerefMut};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Steal<T>(pub Option<T>);
+
+impl<T> Steal<T> {
+	pub fn new(value: T) -> Steal<T> {
+		Steal(Some(value))
+	}
+
+	pub fn steal(&mut self) -> T {
+		self.0
+			.take()
+			.expect("Attempted to steal already stoken value")
+	}
+}
+
+impl<T> From<T> for Steal<T> {
+	fn from(value: T) -> Self {
+		Steal::new(value)
+	}
+}
+
+impl<T> Deref for Steal<T> {
+	type Target = T;
+
+	fn deref(&self) -> &Self::Target {
+		self.0
+			.as_ref()
+			.expect("Attempted to dereference stolen value")
+	}
+}
+
+impl<T> DerefMut for Steal<T> {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		self.0
+			.as_mut()
+			.expect("Attempted to dereference stolen value")
+	}
+}