From 6fc9aa092e33a5c540288dad1b6a4a2b6e4df694 Mon Sep 17 00:00:00 2001
From: Brad Moylan <bmoylan@palantir.com>
Date: Sun, 4 Sep 2022 17:59:34 -0700
Subject: [PATCH] MapContext

---
 refreshable/refreshable.go | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/refreshable/refreshable.go b/refreshable/refreshable.go
index eb5c3499..51fa3b12 100644
--- a/refreshable/refreshable.go
+++ b/refreshable/refreshable.go
@@ -4,6 +4,10 @@
 
 package refreshable
 
+import (
+	"context"
+)
+
 // A Refreshable is a generic container type for a volatile underlying value.
 // It supports atomic access and user-provided callback "subscriptions" on updates.
 type Refreshable[T any] interface {
@@ -63,6 +67,16 @@ func Map[T any, M any](original Refreshable[T], mapFn func(T) M) (Refreshable[M]
 	return out, stop
 }
 
+// MapContext is like Map but unsubscribes when the context is cancelled.
+func MapContext[T any, M any](ctx context.Context, original Refreshable[T], mapFn func(T) M) Refreshable[M] {
+	out, stop := Map(original, mapFn)
+	go func() {
+		<-ctx.Done()
+		stop()
+	}()
+	return out
+}
+
 // MapWithError is similar to Validate but allows for the function to return a mapping/mutation
 // of the input object in addition to returning an error. The returned validRefreshable will contain the mapped value.
 // An error is returned if the current original value fails to map.