changed shards struct to use RWMutex and added executeRead

1 files changed, 38 insertions, 25 deletions

diff --git a/shards.go b/shards.go
index ae6e069..279d9b1 100644
--- a/shards.go
+++ b/shards.go
@@ -6,7 +6,7 @@ import (
 	"sync"
 )
 type Shard struct{
-	mu sync.Mutex
+	mu sync.RWMutex
 	id int
 	data map[string]Item
 }
@@ -25,30 +25,43 @@ func (db *RedisDB) Execute(key string, fn func(*Shard) interface{}) interface{}
     defer shard.mu.Unlock()
     return fn(shard)
 }
-
+func (db *RedisDB) ExecuteRead(key string, fn func(*Shard) interface{}) interface{} {
+    shard := db.getShard(key)
+    shard.mu.RLock()
+    defer shard.mu.RUnlock()
+    return fn(shard)
+}
 func ( db *RedisDB) ExecuteMulti(keys []string, fn func([]*Shard) interface{})interface{}{
-	shardMap := make(map[int]*Shard)
-	for _, k := range keys {
-        shard := db.getShard(k)
-        shardMap[shard.id] = shard
-    }
-	var sortedIDs []int
-    for id := range shardMap {
-        sortedIDs = append(sortedIDs, id)
-    }
-	sort.Ints(sortedIDs)
-	for _, id := range sortedIDs{
-		shardMap[id].mu.Lock()
-	}
-	defer func(){
-		for i := len(sortedIDs)-1; i >= 0; i --{
-			shardMap[sortedIDs[i]].mu.Unlock()
+	if len(keys) == 1{
+		shard := db.getShard(keys[0])
+		shard.mu.Lock()
+		defer shard.mu.Unlock()
+		shards := []*Shard{shard}
+		return fn(shards)
+	}else{
+		shardMap := make(map[int]*Shard)
+		for _, k := range keys {
+			shard := db.getShard(k)
+			shardMap[shard.id] = shard
 		}
-	}()
-	
-	shards := make([]*Shard, 0, len(shardMap))
-    for _, id := range sortedIDs {
-        shards = append(shards, shardMap[id])
-    }
-    return fn(shards)
+		var sortedIDs []int
+		for id := range shardMap {
+			sortedIDs = append(sortedIDs, id)
+		}
+		sort.Ints(sortedIDs)
+		for _, id := range sortedIDs{
+			shardMap[id].mu.Lock()
+		}
+		defer func(){
+			for i := len(sortedIDs)-1; i >= 0; i --{
+				shardMap[sortedIDs[i]].mu.Unlock()
+			}
+		}()
+		
+		shards := make([]*Shard, 0, len(shardMap))
+		for _, id := range sortedIDs {
+			shards = append(shards, shardMap[id])
+		}
+		return fn(shards)
+	}
 }