From c1c1bb2c4c1baf37dbcce96f144966d4ada65ac5 Mon Sep 17 00:00:00 2001
From: Brian Picciano <mediocregopher@gmail.com>
Date: Mon, 23 Jan 2023 22:30:30 +0100
Subject: Implement cache and logger middlewares for gemini

---
 src/cache/cache.go | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 src/cache/cache.go

(limited to 'src/cache/cache.go')

diff --git a/src/cache/cache.go b/src/cache/cache.go
new file mode 100644
index 0000000..ade286a
--- /dev/null
+++ b/src/cache/cache.go
@@ -0,0 +1,49 @@
+// Package cache implements a simple LRU cache which can be completely purged
+// whenever needed.
+package cache
+
+import (
+	lru "github.com/hashicorp/golang-lru"
+)
+
+// Cache describes an in-memory cache for arbitrary objects, which has a Purge
+// method for clearing everything at once.
+type Cache interface {
+	Get(key string) interface{}
+	Set(key string, value interface{})
+	Purge()
+}
+
+type cache struct {
+	cache *lru.Cache
+}
+
+// New instantiates and returns a new Cache which can hold up to the given
+// number of entries.
+func New(size int) Cache {
+	c, err := lru.New(size)
+
+	// instantiating the lru cache can't realistically fail
+	if err != nil {
+		panic(err)
+	}
+
+	return &cache{c}
+}
+
+func (c *cache) Get(key string) interface{} {
+	value, ok := c.cache.Get(key)
+	if !ok {
+		return nil
+	}
+
+	return value
+}
+
+func (c *cache) Set(key string, value interface{}) {
+	c.cache.Add(key, value)
+}
+
+func (c *cache) Purge() {
+	c.cache.Purge()
+}
-- 
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