1 files changed, 46 insertions, 0 deletions
diff --git a/common/hcontext/context.go b/common/hcontext/context.go
new file mode 100644
index 000000000..9524ef284
--- /dev/null
+++ b/common/hcontext/context.go
@@ -0,0 +1,46 @@
+// Copyright 2024 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hcontext
+
+import "context"
+
+// ContextDispatcher is a generic interface for setting and getting values from a context.
+type ContextDispatcher[T any] interface {
+	Set(ctx context.Context, value T) context.Context
+	Get(ctx context.Context) T
+}
+
+// NewContextDispatcher creates a new ContextDispatcher with the given key.
+func NewContextDispatcher[T any, R comparable](key R) ContextDispatcher[T] {
+	return keyInContext[T, R]{
+		id: key,
+	}
+}
+
+type keyInContext[T any, R comparable] struct {
+	zero T
+	id   R
+}
+
+func (f keyInContext[T, R]) Get(ctx context.Context) T {
+	v := ctx.Value(f.id)
+	if v == nil {
+		return f.zero
+	}
+	return v.(T)
+}
+
+func (f keyInContext[T, R]) Set(ctx context.Context, value T) context.Context {
+	return context.WithValue(ctx, f.id, value)
+}