1 files changed, 60 insertions, 0 deletions
diff --git a/vendor/codeberg.org/gruf/go-kv/v2/format/cache.go b/vendor/codeberg.org/gruf/go-kv/v2/format/cache.go
new file mode 100644
index 000000000..8c9bfa210
--- /dev/null
+++ b/vendor/codeberg.org/gruf/go-kv/v2/format/cache.go
@@ -0,0 +1,60 @@
+package format
+
+import (
+	"sync/atomic"
+	"unsafe"
+
+	"codeberg.org/gruf/go-xunsafe"
+)
+
+// cache is a concurrency-safe map[xunsafe.TypeInfo]FormatFunc
+// cache, designed for heavy reads but with unfortunately expensive
+// writes. it is designed such that after some initial load period
+// in which functions are cached by types, all future ops are reads.
+type cache struct{ p unsafe.Pointer }
+
+// Get will check cache for format func under key.
+func (c *cache) Get(t xunsafe.TypeInfo) FormatFunc {
+	if p := c.load(); p != nil {
+		return (*p)[t]
+	}
+	return nil
+}
+
+// Put will place given format func in cache under key, if not already exists.
+func (c *cache) Put(t xunsafe.TypeInfo, fn FormatFunc) {
+	for {
+		p := c.load()
+
+		var cache map[xunsafe.TypeInfo]FormatFunc
+
+		if p != nil {
+			if _, ok := (*p)[t]; ok {
+				return
+			}
+
+			cache = make(map[xunsafe.TypeInfo]FormatFunc, len(*p)+1)
+			for key, value := range *p {
+				cache[key] = value
+			}
+		} else {
+			cache = make(map[xunsafe.TypeInfo]FormatFunc, 1)
+		}
+
+		cache[t] = fn
+
+		if c.cas(p, &cache) {
+			return
+		}
+	}
+}
+
+// load is a typed wrapper around atomic.LoadPointer().
+func (c *cache) load() *map[xunsafe.TypeInfo]FormatFunc {
+	return (*map[xunsafe.TypeInfo]FormatFunc)(atomic.LoadPointer(&c.p))
+}
+
+// cas is a typed wrapper around atomic.CompareAndSwapPointer().
+func (c *cache) cas(old, new *map[xunsafe.TypeInfo]FormatFunc) bool {
+	return atomic.CompareAndSwapPointer(&c.p, unsafe.Pointer(old), unsafe.Pointer(new))
+}