add

README.md

@@ -1,3 +1,43 @@
 # copier
 
 Golang object deep copy library
+
+
+map->map
+slice->slice
+struct->struct
+map->struct
+struct->map
+
+## Usage
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/chenquan/copier"
+)
+
+type User struct {
+	Name string
+	Age  int
+}
+
+type User2 struct {
+	Name string
+	Age  int
+}
+
+func main() {
+	user := User{
+		Name: "chenquan",
+		Age:  18,
+	}
+	user2 := User2{}
+	err := copier.Copy(&user2, &user)
+	if err != nil {
+		fmt.Println(err)
+	}
+	fmt.Println(user2)
+}

copier.go

@@ -0,0 +1,171 @@
+package copier
+
+import (
+	"reflect"
+	"strings"
+)
+
+func Copy(src, dst any, opts ...option) error {
+	opt := getOpt(opts...)
+	return copy(src, dst, opt)
+}
+
+func copy(src, dst any, opt *options) error {
+	var (
+		srcValue = indirect(reflect.ValueOf(dst))
+		dstValue = indirect(reflect.ValueOf(src))
+	)
+
+	if !dstValue.IsValid() {
+		return ErrInvalidCopyFrom
+	}
+
+	if !dstValue.CanSet() {
+		return ErrInvalidCopyDestination
+	}
+
+	return deepCopy(srcValue, dstValue, 0, opt)
+}
+
+func deepCopy(dst, src reflect.Value, depth int, opt *options) error {
+	switch dst.Kind() {
+	case reflect.Slice, reflect.Array:
+		// slice -> slice
+		return copySlice(src, dst, depth, opt)
+	case reflect.Map:
+		switch src.Kind() {
+		case reflect.Map:
+			// map -> map
+			return copyMap(src, dst, depth, opt)
+		case reflect.Struct:
+			// struct -> map
+			return copyStruct2Map(src, dst, depth, opt)
+		default:
+			return ErrNotSupported
+		}
+
+	case reflect.Struct:
+		switch src.Kind() {
+		case reflect.Map:
+			// map -> struct
+			return copyMap2Struct(src, dst, depth, opt)
+		case reflect.Struct:
+			// struct -> struct
+			return copyStruct(src, dst, depth, opt)
+		default:
+			return ErrNotSupported
+		}
+
+	case reflect.Pointer:
+		if dst.IsNil() {
+			if !dst.CanSet() {
+				return ErrInvalidCopyDestination
+			}
+			p := reflect.New(dst.Type().Elem())
+			dst.Set(p)
+		}
+
+		src = src.Elem()
+		dst = dst.Elem()
+		return deepCopy(dst, src, depth, opt)
+	default:
+		return copyDefault(src, dst)
+	}
+}
+
+func copyStruct2Map(src, dst reflect.Value, depth int, opt *options) error {
+	return nil
+}
+
+func copyMap2Struct(src, dst reflect.Value, depth int, opt *options) error {
+	return nil
+}
+
+func copyMap(dst, src reflect.Value, depth int, opt *options) error {
+	if dst.IsNil() {
+		dst.Set(reflect.MakeMapWithSize(dst.Type(), src.Len()))
+	}
+
+	for _, key := range src.MapKeys() {
+		value := src.MapIndex(key)
+		dst.SetMapIndex(key, value)
+	}
+
+	return nil
+}
+
+func copySlice(dst, src reflect.Value, depth int, opt *options) error {
+	len := src.Len()
+	if dst.Len() > 0 && dst.Len() < src.Len() {
+		len = dst.Len()
+	}
+
+	if dst.Kind() == reflect.Slice && dst.Len() == 0 && src.Len() > 0 {
+		dstType := dst.Type().Elem()
+		newDst := reflect.MakeSlice(reflect.SliceOf(dstType), len, len)
+		dst.Set(newDst)
+	}
+
+	for i := 0; i < len; i++ {
+		if err := deepCopy(dst.Index(i), src.Index(i), depth, opt); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func copyStruct(dst, src reflect.Value, depth int, opt *options) error {
+	typ := src.Type()
+	for i := 0; i < typ.NumField(); i++ {
+		sf := typ.Field(i)
+
+		dstValue := fieldByName(dst, sf.Name, opt)
+		if !dstValue.IsValid() {
+			continue
+		}
+
+		if err := deepCopy(dstValue, src.Field(i), depth+1, opt); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func copyDefault(dst, src reflect.Value) error {
+
+	if src.Type().AssignableTo(dst.Type()) || dst.Type().ConvertibleTo(src.Type()) {
+		dst.Set(src.Convert(dst.Type()))
+	}
+
+	switch dst.Kind() {
+
+	}
+
+	return nil
+}
+
+func fieldByName(v reflect.Value, name string, opt *options) reflect.Value {
+	if opt.caseSensitive {
+		return v.FieldByName(name)
+	}
+	return v.FieldByNameFunc(func(s string) bool { return strings.EqualFold(s, name) })
+}
+
+func indirect(reflectValue reflect.Value) reflect.Value {
+	for reflectValue.Kind() == reflect.Pointer {
+		reflectValue = reflectValue.Elem()
+	}
+
+	return reflectValue
+}
+
+func indirectType(reflectType reflect.Type) (_ reflect.Type, isPtr bool) {
+	for reflectType.Kind() == reflect.Pointer || reflectType.Kind() == reflect.Slice {
+		reflectType = reflectType.Elem()
+		isPtr = true
+	}
+
+	return reflectType, isPtr
+}

copier_map_test.go

@@ -0,0 +1,28 @@
+package copier
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCopyMap(t *testing.T) {
+	type person struct {
+		Name string
+		Age  int
+	}
+
+	src := map[string]*person{
+		"John": {
+			Name: "John",
+			Age:  30,
+		},
+	}
+
+	dst := map[string]any{}
+
+	assert.NoError(t, Copy(&dst, src))
+
+	fmt.Println(src, dst)
+}

copier_slice_test.go

@@ -0,0 +1,60 @@
+package copier
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSliceCopy(t *testing.T) {
+	type person struct {
+		Name string
+		Age  int
+	}
+
+	src := []person{
+		{Name: "Alice", Age: 20},
+		{Name: "Bob", Age: 30},
+	}
+
+	dst := []person{}
+
+	Copy(&dst, src)
+
+	// Check if the copy was successful
+	if len(dst) != len(src) {
+		t.Errorf("Expected %d elements, got %d", len(src), len(dst))
+	}
+
+	fmt.Println("dst:", dst)
+}
+
+func TestPtrSliceCopy(t *testing.T) {
+	type person struct {
+		Name string
+		Age  int
+	}
+
+	src := []*person{
+		{Name: "Alice", Age: 20},
+		{Name: "Bob", Age: 30},
+	}
+
+	dst := []*person{}
+
+	Copy(&dst, src)
+
+	// Check if the copy was successful
+	if len(dst) != len(src) {
+		t.Errorf("Expected %d elements, got %d", len(src), len(dst))
+	}
+
+	assert.Equal(t, src[0].Name, dst[0].Name)
+
+	for i := range src {
+		assert.Equal(t, src[i].Name, dst[i].Name)
+		assert.Equal(t, src[i].Age, dst[i].Age)
+		assert.NotSame(t, src[i], dst[i])
+	}
+}

copier_test.go

@@ -0,0 +1,2 @@
+package copier
+

errors.go

@@ -0,0 +1,11 @@
+package copier
+
+import "errors"
+
+var (
+	ErrInvalidCopyDestination        = errors.New("copy destination must be non-nil and addressable")
+	ErrInvalidCopyFrom               = errors.New("copy from must be non-nil and addressable")
+	ErrMapKeyNotMatch                = errors.New("map's key type doesn't match")
+	ErrNotSupported                  = errors.New("not supported")
+	ErrFieldNameTagStartNotUpperCase = errors.New("copier field name tag must be start upper case")
+)

go.mod

@@ -0,0 +1,11 @@
+module git.charlienet.top/go/copier
+
+go 1.25
+
+require github.com/stretchr/testify v1.11.1
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,10 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

optiongs.go

@@ -0,0 +1,118 @@
+package copier
+
+import "reflect"
+
+const (
+	noDepthLimited = -1
+)
+
+type options struct {
+	tagName          string              // 标签名
+	maxDepth         int                 // 最大复制深度
+	ignoreEmpty      bool                // 复制时忽略空字段
+	caseSensitive    bool                // 复制时大小写敏感
+	must             bool                // 只复制具有must标识的字段
+	converters       []TypeConverter     // 类型转换器
+	fieldNameMapping map[string]string   // 字段名转映射
+	nameConverter    func(string) string // 字段名转换器
+}
+
+type option func(*options)
+
+type TypeConverter struct {
+	FieldName string
+	SrcType   any
+	DstType   any
+	Fn        func(src any) (dst any, err error)
+}
+
+type FieldNameConverter struct {
+	SrcFieldName string
+	DstFieldName string
+}
+
+func getOpt(opts ...option) *options {
+	opt := DefaultOptions
+
+	for _, o := range opts {
+		o(opt)
+	}
+
+	return opt
+}
+
+func (opt *options) NameConvert(name string) string {
+	if opt.nameConverter != nil {
+		name = opt.nameConverter(name)
+	}
+
+	if toname, ok := opt.fieldNameMapping[name]; ok {
+		name = toname
+	}
+
+	return name
+}
+
+func (opt options) TypeConvert(value reflect.Value) (reflect.Value, bool) {
+	for _, c := range opt.converters {
+		_ = c
+	}
+	return value, false
+}
+
+func (opt *options) ExceedMaxDepth(depth int) bool {
+	return opt.maxDepth != noDepthLimited && depth > opt.maxDepth
+}
+
+func WithMaxDepth(depth int) option {
+	return func(o *options) {
+		o.maxDepth = depth
+	}
+}
+
+func WithIgnoreEmpty() option {
+	return func(o *options) {
+		o.ignoreEmpty = true
+	}
+}
+
+func WithCaseSensitive() option {
+	return func(o *options) {
+		o.caseSensitive = true
+	}
+}
+
+func WithMust() option {
+	return func(o *options) {
+		o.must = true
+	}
+}
+
+func WithConverters(converters ...TypeConverter) option {
+	return func(o *options) {
+		o.converters = converters
+	}
+}
+
+func WithNameMapping(mappings map[string]string) option {
+	return func(o *options) {
+		o.fieldNameMapping = mappings
+	}
+}
+
+func WithNameFn(fn func(string) string) option {
+	return func(o *options) {
+		o.nameConverter = fn
+	}
+}
+
+func WithTagName(tagName string) option {
+	return func(o *options) {
+		o.tagName = tagName
+	}
+}
+
+var DefaultOptions = &options{
+	maxDepth: noDepthLimited,
+	tagName:  defaultTag,
+}

tags.go

@@ -0,0 +1,63 @@
+package copier
+
+import "strings"
+
+const (
+	defaultTag = "copier"
+)
+
+type tagt uint8
+
+const (
+	tagMust tagt = 1 << iota
+	tagIgnore
+	tagToName
+)
+
+// 标签 copier 取值 must、ignore、toname 等
+// copier:"must,toname=xxx" 必须复制，并重命名为 xxx
+
+type tagOption struct {
+	flg    tagt
+	toname string
+}
+
+func parseTag(tag string) *tagOption {
+	opt := tagOption{}
+
+	flg := tagt(0)
+	for t := range strings.SplitSeq(tag, ",") {
+		tag, value, found := strings.Cut(t, "=")
+		switch tag {
+		case "-", "ignore":
+			flg |= tagIgnore
+		case "must":
+			flg |= tagMust
+		case "toname":
+			flg |= tagToName
+			if found {
+				opt.toname = value
+			}
+		}
+	}
+
+	opt.flg = flg
+
+	return &opt
+}
+
+func (o *tagOption) Contains(tag tagt) bool {
+	if o.flg == 0 {
+		return false
+	}
+
+	return o.flg&tag == tag
+}
+
+func (o *tagOption) ToName() string {
+	if o.flg&tagToName == 0 {
+		return ""
+	}
+
+	return o.toname
+}