1 files changed, 90 insertions, 0 deletions
diff --git a/common/maps/cache.go b/common/maps/cache.go
new file mode 100644
index 000000000..7e23a2662
--- /dev/null
+++ b/common/maps/cache.go
@@ -0,0 +1,90 @@
+// 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 maps
+
+import "sync"
+
+// Cache is a simple thread safe cache backed by a map.
+type Cache[K comparable, T any] struct {
+	m map[K]T
+	sync.RWMutex
+}
+
+// NewCache creates a new Cache.
+func NewCache[K comparable, T any]() *Cache[K, T] {
+	return &Cache[K, T]{m: make(map[K]T)}
+}
+
+// Delete deletes the given key from the cache.
+func (c *Cache[K, T]) Get(key K) (T, bool) {
+	c.RLock()
+	v, found := c.m[key]
+	c.RUnlock()
+	return v, found
+}
+
+// GetOrCreate gets the value for the given key if it exists, or creates it if not.
+func (c *Cache[K, T]) GetOrCreate(key K, create func() T) T {
+	c.RLock()
+	v, found := c.m[key]
+	c.RUnlock()
+	if found {
+		return v
+	}
+	c.Lock()
+	defer c.Unlock()
+	v, found = c.m[key]
+	if found {
+		return v
+	}
+	v = create()
+	c.m[key] = v
+	return v
+}
+
+// Set sets the given key to the given value.
+func (c *Cache[K, T]) Set(key K, value T) {
+	c.Lock()
+	c.m[key] = value
+	c.Unlock()
+}
+
+// SliceCache is a simple thread safe cache backed by a map.
+type SliceCache[T any] struct {
+	m map[string][]T
+	sync.RWMutex
+}
+
+func NewSliceCache[T any]() *SliceCache[T] {
+	return &SliceCache[T]{m: make(map[string][]T)}
+}
+
+func (c *SliceCache[T]) Get(key string) ([]T, bool) {
+	c.RLock()
+	v, found := c.m[key]
+	c.RUnlock()
+	return v, found
+}
+
+func (c *SliceCache[T]) Append(key string, values ...T) {
+	c.Lock()
+	c.m[key] = append(c.m[key], values...)
+	c.Unlock()
+}
+
+func (c *SliceCache[T]) Reset() {
+	c.Lock()
+	c.m = make(map[string][]T)
+	c.Unlock()
+}