lint: fix some Golang CI lint issues (#5955)

2 files changed, 15 insertions, 35 deletions

diff --git a/internal/tool/file.go b/internal/tool/file.go
index 6ca4136a..169bc511 100644
--- a/internal/tool/file.go
+++ b/internal/tool/file.go
@@ -31,26 +31,6 @@ func IsVideoFile(data []byte) bool {
 	return strings.Contains(http.DetectContentType(data), "video/")
 }
 
-const (
-	Byte  = 1
-	KByte = Byte * 1024
-	MByte = KByte * 1024
-	GByte = MByte * 1024
-	TByte = GByte * 1024
-	PByte = TByte * 1024
-	EByte = PByte * 1024
-)
-
-var bytesSizeTable = map[string]uint64{
-	"b":  Byte,
-	"kb": KByte,
-	"mb": MByte,
-	"gb": GByte,
-	"tb": TByte,
-	"pb": PByte,
-	"eb": EByte,
-}
-
 func logn(n, b float64) float64 {
 	return math.Log(n) / math.Log(b)
 }
diff --git a/internal/tool/tool.go b/internal/tool/tool.go
index 7e6fc813..2410b4d6 100644
--- a/internal/tool/tool.go
+++ b/internal/tool/tool.go
@@ -367,37 +367,37 @@ func TimeSince(t time.Time, lang string) template.HTML {
 func Subtract(left interface{}, right interface{}) interface{} {
 	var rleft, rright int64
 	var fleft, fright float64
-	var isInt bool = true
-	switch left.(type) {
+	var isInt = true
+	switch left := left.(type) {
 	case int:
-		rleft = int64(left.(int))
+		rleft = int64(left)
 	case int8:
-		rleft = int64(left.(int8))
+		rleft = int64(left)
 	case int16:
-		rleft = int64(left.(int16))
+		rleft = int64(left)
 	case int32:
-		rleft = int64(left.(int32))
+		rleft = int64(left)
 	case int64:
-		rleft = left.(int64)
+		rleft = left
 	case float32:
-		fleft = float64(left.(float32))
+		fleft = float64(left)
 		isInt = false
 	case float64:
-		fleft = left.(float64)
+		fleft = left
 		isInt = false
 	}
 
-	switch right.(type) {
+	switch right := right.(type) {
 	case int:
-		rright = int64(right.(int))
+		rright = int64(right)
 	case int8:
-		rright = int64(right.(int8))
+		rright = int64(right)
 	case int16:
-		rright = int64(right.(int16))
+		rright = int64(right)
 	case int32:
-		rright = int64(right.(int32))
+		rright = int64(right)
 	case int64:
-		rright = right.(int64)
+		rright = right
 	case float32:
 		fright = float64(left.(float32))
 		isInt = false