blob: 3cc926c7f6245a31a9cbdedcc20f96e1f41c1177 [file] [log] [blame]
Matteo Scandoloa4285862020-12-01 18:10:10 -08001// Copyright 2013 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.
5
6// Based on src/pkg/reflect/deepequal.go from official
7// golang's stdlib.
8
9package mergo
10
11import (
12 "errors"
13 "reflect"
14)
15
16// Errors reported by Mergo when it finds invalid arguments.
17var (
18 ErrNilArguments = errors.New("src and dst must not be nil")
19 ErrDifferentArgumentsTypes = errors.New("src and dst must be of same type")
20 ErrNotSupported = errors.New("only structs and maps are supported")
21 ErrExpectedMapAsDestination = errors.New("dst was expected to be a map")
22 ErrExpectedStructAsDestination = errors.New("dst was expected to be a struct")
23 ErrNonPointerAgument = errors.New("dst must be a pointer")
24)
25
26// During deepMerge, must keep track of checks that are
27// in progress. The comparison algorithm assumes that all
28// checks in progress are true when it reencounters them.
29// Visited are stored in a map indexed by 17 * a1 + a2;
30type visit struct {
31 ptr uintptr
32 typ reflect.Type
33 next *visit
34}
35
36// From src/pkg/encoding/json/encode.go.
37func isEmptyValue(v reflect.Value) bool {
38 switch v.Kind() {
39 case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
40 return v.Len() == 0
41 case reflect.Bool:
42 return !v.Bool()
43 case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
44 return v.Int() == 0
45 case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
46 return v.Uint() == 0
47 case reflect.Float32, reflect.Float64:
48 return v.Float() == 0
49 case reflect.Interface, reflect.Ptr:
50 if v.IsNil() {
51 return true
52 }
53 return isEmptyValue(v.Elem())
54 case reflect.Func:
55 return v.IsNil()
56 case reflect.Invalid:
57 return true
58 }
59 return false
60}
61
62func resolveValues(dst, src interface{}) (vDst, vSrc reflect.Value, err error) {
63 if dst == nil || src == nil {
64 err = ErrNilArguments
65 return
66 }
67 vDst = reflect.ValueOf(dst).Elem()
68 if vDst.Kind() != reflect.Struct && vDst.Kind() != reflect.Map {
69 err = ErrNotSupported
70 return
71 }
72 vSrc = reflect.ValueOf(src)
73 // We check if vSrc is a pointer to dereference it.
74 if vSrc.Kind() == reflect.Ptr {
75 vSrc = vSrc.Elem()
76 }
77 return
78}