1 // Copyright 2014 Dario Castañé. All rights reserved.
2 // Copyright 2009 The Go Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style
4 // license that can be found in the LICENSE file.
6 // Based on src/pkg/reflect/deepequal.go from official
18 func changeInitialCase(s string, mapper func(rune) rune) string {
22 r, n := utf8.DecodeRuneInString(s)
23 return string(mapper(r)) + s[n:]
26 func isExported(field reflect.StructField) bool {
27 r, _ := utf8.DecodeRuneInString(field.Name)
28 return r >= 'A' && r <= 'Z'
31 // Traverses recursively both values, assigning src's fields values to dst.
32 // The map argument tracks comparisons that have already been seen, which allows
33 // short circuiting on recursive types.
34 func deepMap(dst, src reflect.Value, visited map[uintptr]*visit, depth int, config *Config) (err error) {
35 overwrite := config.Overwrite
37 addr := dst.UnsafeAddr()
41 for p := seen; p != nil; p = p.next {
42 if p.ptr == addr && p.typ == typ {
46 // Remember, remember...
47 visited[h] = &visit{addr, typ, seen}
49 zeroValue := reflect.Value{}
52 dstMap := dst.Interface().(map[string]interface{})
53 for i, n := 0, src.NumField(); i < n; i++ {
55 field := srcType.Field(i)
56 if !isExported(field) {
59 fieldName := field.Name
60 fieldName = changeInitialCase(fieldName, unicode.ToLower)
61 if v, ok := dstMap[fieldName]; !ok || (isEmptyValue(reflect.ValueOf(v)) || overwrite) {
62 dstMap[fieldName] = src.Field(i).Interface()
67 v := reflect.New(dst.Type().Elem())
73 srcMap := src.Interface().(map[string]interface{})
74 for key := range srcMap {
75 config.overwriteWithEmptyValue = true
76 srcValue := srcMap[key]
77 fieldName := changeInitialCase(key, unicode.ToUpper)
78 dstElement := dst.FieldByName(fieldName)
79 if dstElement == zeroValue {
80 // We discard it because the field doesn't exist.
83 srcElement := reflect.ValueOf(srcValue)
84 dstKind := dstElement.Kind()
85 srcKind := srcElement.Kind()
86 if srcKind == reflect.Ptr && dstKind != reflect.Ptr {
87 srcElement = srcElement.Elem()
88 srcKind = reflect.TypeOf(srcElement.Interface()).Kind()
89 } else if dstKind == reflect.Ptr {
90 // Can this work? I guess it can't.
91 if srcKind != reflect.Ptr && srcElement.CanAddr() {
92 srcPtr := srcElement.Addr()
93 srcElement = reflect.ValueOf(srcPtr)
98 if !srcElement.IsValid() {
101 if srcKind == dstKind {
102 if err = deepMerge(dstElement, srcElement, visited, depth+1, config); err != nil {
105 } else if dstKind == reflect.Interface && dstElement.Kind() == reflect.Interface {
106 if err = deepMerge(dstElement, srcElement, visited, depth+1, config); err != nil {
109 } else if srcKind == reflect.Map {
110 if err = deepMap(dstElement, srcElement, visited, depth+1, config); err != nil {
114 return fmt.Errorf("type mismatch on %s field: found %v, expected %v", fieldName, srcKind, dstKind)
121 // Map sets fields' values in dst from src.
122 // src can be a map with string keys or a struct. dst must be the opposite:
123 // if src is a map, dst must be a valid pointer to struct. If src is a struct,
124 // dst must be map[string]interface{}.
125 // It won't merge unexported (private) fields and will do recursively
126 // any exported field.
127 // If dst is a map, keys will be src fields' names in lower camel case.
128 // Missing key in src that doesn't match a field in dst will be skipped. This
129 // doesn't apply if dst is a map.
130 // This is separated method from Merge because it is cleaner and it keeps sane
131 // semantics: merging equal types, mapping different (restricted) types.
132 func Map(dst, src interface{}, opts ...func(*Config)) error {
133 return _map(dst, src, opts...)
136 // MapWithOverwrite will do the same as Map except that non-empty dst attributes will be overridden by
137 // non-empty src attribute values.
138 // Deprecated: Use Map(…) with WithOverride
139 func MapWithOverwrite(dst, src interface{}, opts ...func(*Config)) error {
140 return _map(dst, src, append(opts, WithOverride)...)
143 func _map(dst, src interface{}, opts ...func(*Config)) error {
145 vDst, vSrc reflect.Value
150 for _, opt := range opts {
154 if vDst, vSrc, err = resolveValues(dst, src); err != nil {
157 // To be friction-less, we redirect equal-type arguments
158 // to deepMerge. Only because arguments can be anything.
159 if vSrc.Kind() == vDst.Kind() {
160 return deepMerge(vDst, vSrc, make(map[uintptr]*visit), 0, config)
164 if vDst.Kind() != reflect.Map {
165 return ErrExpectedMapAsDestination
168 if vDst.Kind() != reflect.Struct {
169 return ErrExpectedStructAsDestination
172 return ErrNotSupported
174 return deepMap(vDst, vSrc, make(map[uintptr]*visit), 0, config)