From 16f82b02a07110ae3f4133758d3a7e20ca2401ea Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sun, 29 Sep 2024 04:18:47 +0000
Subject: [PATCH] add util to restore state on scope exit

Signed-off-by: Jason Volk <jason@zemos.net>
---
 src/core/utils/defer.rs | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/core/utils/defer.rs b/src/core/utils/defer.rs
index 08477b6f..29199700 100644
--- a/src/core/utils/defer.rs
+++ b/src/core/utils/defer.rs
@@ -15,8 +15,14 @@ macro_rules! defer {
 	};
 
 	($body:expr) => {
-		$crate::defer! {{
-			$body
-		}}
+		$crate::defer! {{ $body }}
+	};
+}
+
+#[macro_export]
+macro_rules! scope_restore {
+	($val:ident, $ours:expr) => {
+		let theirs = $crate::utils::exchange($val, $ours);
+		$crate::defer! {{ *$val = theirs; }};
 	};
 }