1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
// Copyright 2014 Dario Castañé. All rights reserved.
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Based on src/pkg/reflect/deepequal.go from official
// golang's stdlib.
package mergo
import (
"fmt"
"reflect"
"unicode"
"unicode/utf8"
)
func changeInitialCase(s string, mapper func(rune) rune) string {
if s == "" {
return s
}
r, n := utf8.DecodeRuneInString(s)
return string(mapper(r)) + s[n:]
}
func isExported(field reflect.StructField) bool {
r, _ := utf8.DecodeRuneInString(field.Name)
return r >= 'A' && r <= 'Z'
}
// Traverses recursively both values, assigning src's fields values to dst.
// The map argument tracks comparisons that have already been seen, which allows
// short circuiting on recursive types.
func deepMap(dst, src reflect.Value, visited map[uintptr]*visit, depth int, config *Config) (err error) {
overwrite := config.Overwrite
if dst.CanAddr() {
addr := dst.UnsafeAddr()
h := 17 * addr
seen := visited[h]
typ := dst.Type()
for p := seen; p != nil; p = p.next {
if p.ptr == addr && p.typ == typ {
return nil
}
}
// Remember, remember...
visited[h] = &visit{addr, typ, seen}
}
zeroValue := reflect.Value{}
switch dst.Kind() {
case reflect.Map:
dstMap := dst.Interface().(map[string]interface{})
for i, n := 0, src.NumField(); i < n; i++ {
srcType := src.Type()
field := srcType.Field(i)
if !isExported(field) {
continue
}
fieldName := field.Name
fieldName = changeInitialCase(fieldName, unicode.ToLower)
if v, ok := dstMap[fieldName]; !ok || (isEmptyValue(reflect.ValueOf(v)) || overwrite) {
dstMap[fieldName] = src.Field(i).Interface()
}
}
case reflect.Ptr:
if dst.IsNil() {
v := reflect.New(dst.Type().Elem())
dst.Set(v)
}
dst = dst.Elem()
fallthrough
case reflect.Struct:
srcMap := src.Interface().(map[string]interface{})
for key := range srcMap {
srcValue := srcMap[key]
fieldName := changeInitialCase(key, unicode.ToUpper)
dstElement := dst.FieldByName(fieldName)
if dstElement == zeroValue {
// We discard it because the field doesn't exist.
continue
}
srcElement := reflect.ValueOf(srcValue)
dstKind := dstElement.Kind()
srcKind := srcElement.Kind()
if srcKind == reflect.Ptr && dstKind != reflect.Ptr {
srcElement = srcElement.Elem()
srcKind = reflect.TypeOf(srcElement.Interface()).Kind()
} else if dstKind == reflect.Ptr {
// Can this work? I guess it can't.
if srcKind != reflect.Ptr && srcElement.CanAddr() {
srcPtr := srcElement.Addr()
srcElement = reflect.ValueOf(srcPtr)
srcKind = reflect.Ptr
}
}
if !srcElement.IsValid() {
continue
}
if srcKind == dstKind {
if err = deepMerge(dstElement, srcElement, visited, depth+1, config); err != nil {
return
}
} else if dstKind == reflect.Interface && dstElement.Kind() == reflect.Interface {
if err = deepMerge(dstElement, srcElement, visited, depth+1, config); err != nil {
return
}
} else if srcKind == reflect.Map {
if err = deepMap(dstElement, srcElement, visited, depth+1, config); err != nil {
return
}
} else {
return fmt.Errorf("type mismatch on %s field: found %v, expected %v", fieldName, srcKind, dstKind)
}
}
}
return
}
// Map sets fields' values in dst from src.
// src can be a map with string keys or a struct. dst must be the opposite:
// if src is a map, dst must be a valid pointer to struct. If src is a struct,
// dst must be map[string]interface{}.
// It won't merge unexported (private) fields and will do recursively
// any exported field.
// If dst is a map, keys will be src fields' names in lower camel case.
// Missing key in src that doesn't match a field in dst will be skipped. This
// doesn't apply if dst is a map.
// This is separated method from Merge because it is cleaner and it keeps sane
// semantics: merging equal types, mapping different (restricted) types.
func Map(dst, src interface{}, opts ...func(*Config)) error {
return _map(dst, src, opts...)
}
// MapWithOverwrite will do the same as Map except that non-empty dst attributes will be overridden by
// non-empty src attribute values.
// Deprecated: Use Map(…) with WithOverride
func MapWithOverwrite(dst, src interface{}, opts ...func(*Config)) error {
return _map(dst, src, append(opts, WithOverride)...)
}
func _map(dst, src interface{}, opts ...func(*Config)) error {
var (
vDst, vSrc reflect.Value
err error
)
config := &Config{}
for _, opt := range opts {
opt(config)
}
if vDst, vSrc, err = resolveValues(dst, src); err != nil {
return err
}
// To be friction-less, we redirect equal-type arguments
// to deepMerge. Only because arguments can be anything.
if vSrc.Kind() == vDst.Kind() {
return deepMerge(vDst, vSrc, make(map[uintptr]*visit), 0, config)
}
switch vSrc.Kind() {
case reflect.Struct:
if vDst.Kind() != reflect.Map {
return ErrExpectedMapAsDestination
}
case reflect.Map:
if vDst.Kind() != reflect.Struct {
return ErrExpectedStructAsDestination
}
default:
return ErrNotSupported
}
return deepMap(vDst, vSrc, make(map[uintptr]*visit), 0, config)
}
|
