From 79dc9f00908f1bc9d46d5c5eeadada11a02b08d1 Mon Sep 17 00:00:00 2001
From: Simon J Mudd <sjmudd@pobox.com>
Date: Tue, 25 Nov 2014 23:25:10 +0100
Subject: [PATCH] Provide a simplistic key value cache to reduce regexp usage
---
key_value_cache/key_value_cache.go | 55 ++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
create mode 100644 key_value_cache/key_value_cache.go
diff --git a/key_value_cache/key_value_cache.go b/key_value_cache/key_value_cache.go
new file mode 100644
index 0000000..e5881b6
--- /dev/null
+++ b/key_value_cache/key_value_cache.go
@@ -0,0 +1,55 @@
+package key_value_cache
+
+import (
+ "errors"
+
+ "github.com/sjmudd/pstop/lib"
+)
+
+// provide a mapping from filename to table.schema etc
+type KeyValueCache struct {
+ cache map[string]string
+ read_requests, served_from_cache, write_requests int
+}
+
+// create a new KeyValueCache entry
+func NewKeyValueCache() KeyValueCache {
+ lib.Logger.Println("KeyValueCache()")
+ var kvc KeyValueCache
+
+ return kvc
+}
+
+// return value if found
+func (kvc *KeyValueCache) Get(key string) (result string, err error) {
+ lib.Logger.Println("KeyValueCache.Get(", key, ")")
+ if kvc.cache == nil {
+ lib.Logger.Println("KeyValueCache.Get() kvc.cache is empty so enabling it")
+ kvc.cache = make(map[string]string)
+ kvc.read_requests = 0
+ kvc.served_from_cache = 0
+ kvc.write_requests = 0
+ }
+
+ kvc.read_requests++
+
+ if result, ok := kvc.cache[key]; ok {
+ kvc.served_from_cache++
+ lib.Logger.Println("Found: read_requests/servced_from_cache:", kvc.read_requests, kvc.served_from_cache)
+ return result, nil
+ } else {
+ lib.Logger.Println("Not found: read_requests/served_from_cache:", kvc.read_requests, kvc.served_from_cache)
+ return "", errors.New("Not found")
+ }
+}
+
+// write to cache and return value
+func (kvc *KeyValueCache) Put(key, value string) string {
+ lib.Logger.Println("KeyValueCache.Put(", key, ",", value, ")")
+ kvc.cache[key] = value
+ return value
+}
+
+func (kvc *KeyValueCache) Statistics() (int, int, int) {
+ return kvc.read_requests, kvc.served_from_cache, kvc.write_requests
+}
--
2.20.1