bencode: Avoid an extra getTags call

diff --git a/bencode/decode.go b/bencode/decode.go
index 4e9e197ae42b7a00f4e096f5c515190faf83f8e0..e0ff3874cb0096b45bc7189138a043ffade7e6e3 100644 (file)
--- a/bencode/decode.go
+++ b/bencode/decode.go
@@ -225,56 +225,62 @@ func getDictField(dict reflect.Value, key string) dictField {
                if !ok {
                        return dictField{}
                }
-               if sf.PkgPath != "" {
+               if sf.r.PkgPath != "" {
                        panic(&UnmarshalFieldError{
                                Key:   key,
                                Type:  dict.Type(),
-                               Field: sf,
+                               Field: sf.r,
                        })
                }
                return dictField{
-                       Value:                    dict.FieldByIndex(sf.Index),
+                       Value:                    dict.FieldByIndex(sf.r.Index),
                        Ok:                       true,
                        Set:                      func() {},
-                       IgnoreUnmarshalTypeError: getTag(sf.Tag).IgnoreUnmarshalTypeError(),
+                       IgnoreUnmarshalTypeError: sf.tag.IgnoreUnmarshalTypeError(),
                }
        default:
                return dictField{}
        }
 }
 
+type structField struct {
+       r   reflect.StructField
+       tag tag
+}
+
 var (
        structFieldsMu sync.Mutex
-       structFields   = map[reflect.Type]map[string]reflect.StructField{}
+       structFields   = map[reflect.Type]map[string]structField{}
 )
 
-func parseStructFields(struct_ reflect.Type, each func(string, reflect.StructField)) {
+func parseStructFields(struct_ reflect.Type, each func(string, structField)) {
        for i, n := 0, struct_.NumField(); i < n; i++ {
                f := struct_.Field(i)
-               tag := f.Tag.Get("bencode")
-               if tag == "-" {
+               if f.Anonymous {
                        continue
                }
-               if f.Anonymous {
+               tagStr := f.Tag.Get("bencode")
+               if tagStr == "-" {
                        continue
                }
-               if key := parseTag(tag).Key(); key != "" {
-                       each(key, f)
-               } else {
-                       each(f.Name, f)
+               tag := parseTag(tagStr)
+               key := tag.Key()
+               if key == "" {
+                       key = f.Name
                }
+               each(key, structField{f, tag})
        }
 }
 
 func saveStructFields(struct_ reflect.Type) {
-       m := make(map[string]reflect.StructField)
-       parseStructFields(struct_, func(key string, sf reflect.StructField) {
+       m := make(map[string]structField)
+       parseStructFields(struct_, func(key string, sf structField) {
                m[key] = sf
        })
        structFields[struct_] = m
 }
 
-func getStructFieldForKey(struct_ reflect.Type, key string) (f reflect.StructField, ok bool) {
+func getStructFieldForKey(struct_ reflect.Type, key string) (f structField, ok bool) {
        structFieldsMu.Lock()
        if _, ok := structFields[struct_]; !ok {
                saveStructFields(struct_)