json: simplify omitempty handling

Author: extemporalgenome

json/codec.go

@@ -896,63 +896,40 @@ func isValidTag(s string) bool {
 }
 
 func emptyFuncOf(t reflect.Type) emptyFunc {
-	switch t {
-	case bytesType, rawMessageType:
-		return func(p unsafe.Pointer) bool { return (*slice)(p).len == 0 }
-	}
-
 	switch t.Kind() {
 	case reflect.Array:
 		if t.Len() == 0 {
 			return func(unsafe.Pointer) bool { return true }
 		}
 
-	case reflect.Map:
-		return func(p unsafe.Pointer) bool { return reflect.NewAt(t, p).Elem().Len() == 0 }
-
-	case reflect.Slice:
-		return func(p unsafe.Pointer) bool { return (*slice)(p).len == 0 }
-
-	case reflect.String:
-		return func(p unsafe.Pointer) bool { return len(*(*string)(p)) == 0 }
+	case reflect.Map, reflect.Slice, reflect.String:
+		return func(p unsafe.Pointer) bool { return reflectDeref(t, p).Len() == 0 }
 
 	case reflect.Bool:
-		return func(p unsafe.Pointer) bool { return !*(*bool)(p) }
-
-	case reflect.Int, reflect.Uint:
-		return func(p unsafe.Pointer) bool { return *(*uint)(p) == 0 }
-
-	case reflect.Uintptr:
-		return func(p unsafe.Pointer) bool { return *(*uintptr)(p) == 0 }
-
+		fallthrough
+	case reflect.Int, reflect.Uint, reflect.Uintptr:
+		fallthrough
 	case reflect.Int8, reflect.Uint8:
-		return func(p unsafe.Pointer) bool { return *(*uint8)(p) == 0 }
-
+		fallthrough
 	case reflect.Int16, reflect.Uint16:
-		return func(p unsafe.Pointer) bool { return *(*uint16)(p) == 0 }
-
+		fallthrough
 	case reflect.Int32, reflect.Uint32:
-		return func(p unsafe.Pointer) bool { return *(*uint32)(p) == 0 }
-
+		fallthrough
 	case reflect.Int64, reflect.Uint64:
-		return func(p unsafe.Pointer) bool { return *(*uint64)(p) == 0 }
-
-	case reflect.Float32:
-		return func(p unsafe.Pointer) bool { return *(*float32)(p) == 0 }
-
-	case reflect.Float64:
-		return func(p unsafe.Pointer) bool { return *(*float64)(p) == 0 }
-
-	case reflect.Ptr:
-		return func(p unsafe.Pointer) bool { return *(*unsafe.Pointer)(p) == nil }
-
-	case reflect.Interface:
-		return func(p unsafe.Pointer) bool { return (*iface)(p).ptr == nil }
+		fallthrough
+	case reflect.Float32, reflect.Float64:
+		fallthrough
+	case reflect.Pointer, reflect.Interface:
+		return func(p unsafe.Pointer) bool { return reflectDeref(t, p).IsZero() }
 	}
 
 	return func(unsafe.Pointer) bool { return false }
 }
 
+func reflectDeref(t reflect.Type, p unsafe.Pointer) reflect.Value {
+	return reflect.NewAt(t, p).Elem()
+}
+
 type iface struct {
 	typ unsafe.Pointer
 	ptr unsafe.Pointer