Add a HTTP cache for remote resources.

Fixes #12502
Closes #11891

common/types/closer.go

@@ -0,0 +1,47 @@
+// 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 types
+
+import "sync"
+
+type Closer interface {
+	Close() error
+}
+
+type CloseAdder interface {
+	Add(Closer)
+}
+
+type Closers struct {
+	mu sync.Mutex
+	cs []Closer
+}
+
+func (cs *Closers) Add(c Closer) {
+	cs.mu.Lock()
+	defer cs.mu.Unlock()
+	cs.cs = append(cs.cs, c)
+}
+
+func (cs *Closers) Close() error {
+	cs.mu.Lock()
+	defer cs.mu.Unlock()
+	for _, c := range cs.cs {
+		c.Close()
+	}
+
+	cs.cs = cs.cs[:0]
+
+	return nil
+}