add utils of incr&decr for cache

client/cache/calc_utils.go

@@ -0,0 +1,83 @@
+package cache
+
+import (
+	"fmt"
+	"math"
+)
+
+func incr(originVal interface{}) (interface{}, error) {
+	switch val := originVal.(type) {
+	case int:
+		tmp := val + 1
+		if val > 0 && tmp < 0 {
+			return nil, fmt.Errorf("increment would overflow")
+		}
+		return tmp, nil
+	case int32:
+		if val == math.MaxInt32 {
+			return nil, fmt.Errorf("increment would overflow")
+		}
+		return val + 1, nil
+	case int64:
+		// if val == math.MaxInt64 {
+		// 	return nil, fmt.Errorf("increment would overflow")
+		// }
+		return val + 1, nil
+	case uint:
+		tmp := val + 1
+		if tmp < val {
+			return nil, fmt.Errorf("increment would overflow")
+		}
+		return tmp, nil
+	case uint32:
+		if val == math.MaxUint32 {
+			return nil, fmt.Errorf("increment would overflow")
+		}
+		return val + 1, nil
+	case uint64:
+		if val == math.MaxUint64 {
+			return nil, fmt.Errorf("increment would overflow")
+		}
+		return val + 1, nil
+	default:
+		return nil, fmt.Errorf("item val is not (u)int (u)int32 (u)int64")
+	}
+}
+
+func decr(originVal interface{}) (interface{}, error) {
+	switch val := originVal.(type) {
+	case int:
+		tmp := val - 1
+		if val < 0 && tmp > 0 {
+			return nil, fmt.Errorf("decrement would overflow")
+		}
+		return tmp, nil
+	case int32:
+		if val == math.MinInt32 {
+			return nil, fmt.Errorf("decrement would overflow")
+		}
+		return val - 1, nil
+	case int64:
+		if val == math.MinInt64 {
+			return nil, fmt.Errorf("decrement would overflow")
+		}
+		return val - 1, nil
+	case uint:
+		if val == 0 {
+			return nil, fmt.Errorf("decrement would overflow")
+		}
+		return val - 1, nil
+	case uint32:
+		if val == 0 {
+			return nil, fmt.Errorf("increment would overflow")
+		}
+		return val - 1, nil
+	case uint64:
+		if val == 0 {
+			return nil, fmt.Errorf("increment would overflow")
+		}
+		return val - 1, nil
+	default:
+		return nil, fmt.Errorf("item val is not (u)int (u)int32 (u)int64")
+	}
+}

client/cache/file.go

@@ -199,25 +199,12 @@ func (fc *FileCache) Incr(ctx context.Context, key string) error {
 		return err
 	}
 
-	var res interface{}
+	val, err := incr(data)
-	switch val := data.(type) {
+	if err != nil {
-	case int:
+		return err
-		res = val + 1
-	case int32:
-		res = val + 1
-	case int64:
-		res = val + 1
-	case uint:
-		res = val + 1
-	case uint32:
-		res = val + 1
-	case uint64:
-		res = val + 1
-	default:
-		return errors.Errorf("data is not (u)int (u)int32 (u)int64")
 	}
 
-	return fc.Put(context.Background(), key, res, time.Duration(fc.EmbedExpiry))
+	return fc.Put(context.Background(), key, val, time.Duration(fc.EmbedExpiry))
 }
 
 // Decr decreases cached int value.
@@ -227,37 +214,12 @@ func (fc *FileCache) Decr(ctx context.Context, key string) error {
 		return err
 	}
 
-	var res interface{}
+	val, err := decr(data)
-	switch val := data.(type) {
+	if err != nil {
-	case int:
+		return err
-		res = val - 1
-	case int32:
-		res = val - 1
-	case int64:
-		res = val - 1
-	case uint:
-		if val > 0 {
-			res = val - 1
-		} else {
-			return errors.New("data val is less than 0")
-		}
-	case uint32:
-		if val > 0 {
-			res = val - 1
-		} else {
-			return errors.New("data val is less than 0")
-		}
-	case uint64:
-		if val > 0 {
-			res = val - 1
-		} else {
-			return errors.New("data val is less than 0")
-		}
-	default:
-		return errors.Errorf("data is not (u)int (u)int32 (u)int64")
 	}
 
-	return fc.Put(context.Background(), key, res, time.Duration(fc.EmbedExpiry))
+	return fc.Put(context.Background(), key, val, time.Duration(fc.EmbedExpiry))
 }
 
 // IsExist checks if value exists.

client/cache/memory.go

@@ -130,22 +130,12 @@ func (bc *MemoryCache) Incr(ctx context.Context, key string) error {
 	if !ok {
 		return errors.New("key not exist")
 	}
-	switch val := itm.val.(type) {
+
-	case int:
+	val, err := incr(itm.val)
-		itm.val = val + 1
+	if err != nil {
-	case int32:
+		return err
-		itm.val = val + 1
-	case int64:
-		itm.val = val + 1
-	case uint:
-		itm.val = val + 1
-	case uint32:
-		itm.val = val + 1
-	case uint64:
-		itm.val = val + 1
-	default:
-		return errors.New("item val is not (u)int (u)int32 (u)int64")
 	}
+	itm.val = val
 	return nil
 }
 
@@ -157,34 +147,12 @@ func (bc *MemoryCache) Decr(ctx context.Context, key string) error {
 	if !ok {
 		return errors.New("key not exist")
 	}
-	switch val := itm.val.(type) {
+
-	case int:
+	val, err := decr(itm.val)
-		itm.val = val - 1
+	if err != nil {
-	case int64:
+		return err
-		itm.val = val - 1
-	case int32:
-		itm.val = val - 1
-	case uint:
-		if val > 0 {
-			itm.val = val - 1
-		} else {
-			return errors.New("item val is less than 0")
-		}
-	case uint32:
-		if val > 0 {
-			itm.val = val - 1
-		} else {
-			return errors.New("item val is less than 0")
-		}
-	case uint64:
-		if val > 0 {
-			itm.val = val - 1
-		} else {
-			return errors.New("item val is less than 0")
-		}
-	default:
-		return errors.New("item val is not int int64 int32")
 	}
+	itm.val = val
 	return nil
 }