improve converter feature for package gconv (#3211)

example/config/apollo/boot/boot.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package boot
 
 import (

example/config/apollo/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/config/consul/boot/boot.go

@@ -1,12 +1,19 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package boot
 
 import (
 	consul "github.com/gogf/gf/contrib/config/consul/v2"
 
-	"github.com/gogf/gf/v2/frame/g"
-	"github.com/gogf/gf/v2/os/gctx"
 	"github.com/hashicorp/consul/api"
 	"github.com/hashicorp/go-cleanhttp"
+
+	"github.com/gogf/gf/v2/frame/g"
+	"github.com/gogf/gf/v2/os/gctx"
 )
 
 func init() {

example/config/consul/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/config/kubecm/boot_in_pod/boot.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package boot
 
 import (

example/config/kubecm/boot_out_pod/boot.go

@@ -1,10 +1,17 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package boot
 
 import (
+	"k8s.io/client-go/kubernetes"
+
 	"github.com/gogf/gf/contrib/config/kubecm/v2"
 	"github.com/gogf/gf/v2/frame/g"
 	"github.com/gogf/gf/v2/os/gctx"
-	"k8s.io/client-go/kubernetes"
 )
 
 const (

example/config/kubecm/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/config/nacos/boot/boot.go

@@ -1,11 +1,18 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package boot
 
 import (
+	"github.com/nacos-group/nacos-sdk-go/common/constant"
+	"github.com/nacos-group/nacos-sdk-go/vo"
+
 	"github.com/gogf/gf/contrib/config/nacos/v2"
 	"github.com/gogf/gf/v2/frame/g"
 	"github.com/gogf/gf/v2/os/gctx"
-	"github.com/nacos-group/nacos-sdk-go/common/constant"
-	"github.com/nacos-group/nacos-sdk-go/vo"
 )
 
 func init() {

example/config/nacos/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package nacos
 
 import (

example/converter/alias_type_convert_with_refer/main.go

@@ -0,0 +1,58 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/gogf/gf/v2/os/gtime"
+	"github.com/gogf/gf/v2/util/gconv"
+)
+
+type MyTime = *gtime.Time
+
+type Src struct {
+	A MyTime
+}
+
+type Dst struct {
+	B string
+}
+
+type SrcWrap struct {
+	Value Src
+}
+
+type DstWrap struct {
+	Value Dst
+}
+
+// SrcToDstConverter is custom converting function for custom type.
+func SrcToDstConverter(src Src) (dst *Dst, err error) {
+	return &Dst{B: src.A.Format("Y-m-d")}, nil
+}
+
+// SrcToDstConverter is custom converting function for custom type.
+func main() {
+	// register custom converter function.
+	err := gconv.RegisterConverter(SrcToDstConverter)
+	if err != nil {
+		panic(err)
+	}
+
+	// custom struct converting.
+	var src = Src{A: gtime.Now()}
+	dst := gconv.ConvertWithRefer(src, &Dst{})
+	fmt.Println("src:", src)
+	fmt.Println("dst:", dst)
+
+	// custom struct attributes converting.
+	var srcWrap = SrcWrap{Src{A: gtime.Now()}}
+	dstWrap := gconv.ConvertWithRefer(srcWrap, &DstWrap{})
+	fmt.Println("srcWrap:", srcWrap)
+	fmt.Println("dstWrap:", dstWrap)
+}

example/converter/alias_type_scan/main.go

@@ -0,0 +1,72 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/gogf/gf/v2/os/gtime"
+	"github.com/gogf/gf/v2/util/gconv"
+)
+
+type MyTime = *gtime.Time
+
+type Src struct {
+	A MyTime
+}
+
+type Dst struct {
+	B string
+}
+
+type SrcWrap struct {
+	Value Src
+}
+
+type DstWrap struct {
+	Value Dst
+}
+
+// SrcToDstConverter is custom converting function for custom type.
+func SrcToDstConverter(src Src) (dst *Dst, err error) {
+	return &Dst{B: src.A.Format("Y-m-d")}, nil
+}
+
+// SrcToDstConverter is custom converting function for custom type.
+func main() {
+	// register custom converter function.
+	err := gconv.RegisterConverter(SrcToDstConverter)
+	if err != nil {
+		panic(err)
+	}
+
+	// custom struct converting.
+	var (
+		src = Src{A: gtime.Now()}
+		dst *Dst
+	)
+	err = gconv.Scan(src, &dst)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("src:", src)
+	fmt.Println("dst:", dst)
+
+	// custom struct attributes converting.
+	var (
+		srcWrap = SrcWrap{Src{A: gtime.Now()}}
+		dstWrap *DstWrap
+	)
+	err = gconv.Scan(srcWrap, &dstWrap)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("srcWrap:", srcWrap)
+	fmt.Println("dstWrap:", dstWrap)
+}

example/converter/struct_convert_with_refer/main.go

@@ -0,0 +1,54 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/gogf/gf/v2/util/gconv"
+)
+
+type Src struct {
+	A int
+}
+
+type Dst struct {
+	B int
+}
+
+type SrcWrap struct {
+	Value Src
+}
+
+type DstWrap struct {
+	Value Dst
+}
+
+// SrcToDstConverter is custom converting function for custom type.
+func SrcToDstConverter(src Src) (dst *Dst, err error) {
+	return &Dst{B: src.A}, nil
+}
+
+func main() {
+	// register custom converter function.
+	err := gconv.RegisterConverter(SrcToDstConverter)
+	if err != nil {
+		panic(err)
+	}
+
+	// custom struct converting.
+	var src = Src{A: 1}
+	dst := gconv.ConvertWithRefer(src, Dst{})
+	fmt.Println("src:", src)
+	fmt.Println("dst:", dst)
+
+	// custom struct attributes converting.
+	var srcWrap = SrcWrap{Src{A: 1}}
+	dstWrap := gconv.ConvertWithRefer(srcWrap, &DstWrap{})
+	fmt.Println("srcWrap:", srcWrap)
+	fmt.Println("dstWrap:", dstWrap)
+}

example/converter/struct_scan/main.go

@@ -0,0 +1,68 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/gogf/gf/v2/util/gconv"
+)
+
+type Src struct {
+	A int
+}
+
+type Dst struct {
+	B int
+}
+
+type SrcWrap struct {
+	Value Src
+}
+
+type DstWrap struct {
+	Value Dst
+}
+
+func SrcToDstConverter(src Src) (dst *Dst, err error) {
+	return &Dst{B: src.A}, nil
+}
+
+// SrcToDstConverter is custom converting function for custom type.
+func main() {
+	// register custom converter function.
+	err := gconv.RegisterConverter(SrcToDstConverter)
+	if err != nil {
+		panic(err)
+	}
+
+	// custom struct converting.
+	var (
+		src = Src{A: 1}
+		dst *Dst
+	)
+	err = gconv.Scan(src, &dst)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("src:", src)
+	fmt.Println("dst:", dst)
+
+	// custom struct attributes converting.
+	var (
+		srcWrap = SrcWrap{Src{A: 1}}
+		dstWrap *DstWrap
+	)
+	err = gconv.Scan(srcWrap, &dstWrap)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("srcWrap:", srcWrap)
+	fmt.Println("dstWrap:", dstWrap)
+}

example/httpserver/default_value/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/httpserver/proxy/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/httpserver/rate/main.go

@@ -1,12 +1,19 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (
 	"context"
 	"fmt"
 
+	"golang.org/x/time/rate"
+
 	"github.com/gogf/gf/v2/frame/g"
 	"github.com/gogf/gf/v2/net/ghttp"
-	"golang.org/x/time/rate"
 )
 
 type HelloReq struct {

example/httpserver/response_with_json_array/controller.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/httpserver/response_with_json_array/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/httpserver/swagger/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/nosql/redis/configuration/basic/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/nosql/redis/configuration/senior/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/nosql/redis/expire/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/nosql/redis/hmset/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/nosql/redis/hset/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/nosql/redis/key-value/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/os/log/rotate/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/pack/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/pack/packed/paked.go

@@ -1 +1,7 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package packed

example/registry/etcd/http/client/client.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/registry/etcd/http/server/server.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/registry/file/client/client.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/registry/file/server/server.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/rpc/grpcx/rawgrpc/client/client.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/rpc/grpcx/rawgrpc/server/server.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/tcp/server/proxy/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/grpc_with_db/client/client.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/grpc_with_db/server/server.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/http/client/client.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/http/server/server.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/http_with_db/client/client.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/http_with_db/server/server.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/inprocess/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/processes/gcmd/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/processes/gcmd/sub/sub.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/processes/gproc/main.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

example/trace/processes/gproc/sub/sub.go

@@ -1,3 +1,9 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
 package main
 
 import (

util/gconv/gconv_convert.go

@@ -280,6 +280,17 @@ func doConvert(in doConvertInput) (convertedValue interface{}) {
 			} else {
 				referReflectValue = reflect.ValueOf(in.ReferValue)
 			}
+			var fromReflectValue reflect.Value
+			if v, ok := in.FromValue.(reflect.Value); ok {
+				fromReflectValue = v
+			} else {
+				fromReflectValue = reflect.ValueOf(in.FromValue)
+			}
+
+			// custom converter.
+			if dstReflectValue, ok, _ := callCustomConverterWithRefer(fromReflectValue, referReflectValue); ok {
+				return dstReflectValue.Interface()
+			}
 
 			defer func() {
 				if recover() != nil {

util/gconv/gconv_converter.go

@@ -24,7 +24,7 @@ var customConverters = make(map[converterInType]map[converterOutType]converterFu
 
 // RegisterConverter to register custom converter.
 // It must be registered before you use this custom converting feature.
-// It is suggested to do it in boot.
+// It is suggested to do it in boot procedure of the process.
 //
 // Note:
 //  1. The parameter `fn` must be defined as pattern `func(T1) (T2, error)`.
@@ -40,7 +40,7 @@ func RegisterConverter(fn interface{}) (err error) {
 		!fnReflectType.Out(1).Implements(errType) {
 		err = gerror.NewCodef(
 			gcode.CodeInvalidParameter,
-			"parameter must be type of function and defined as pattern `func(T1) (T2, error)`, but defined as `%s`",
+			"parameter must be type of converter function and defined as pattern `func(T1) (T2, error)`, but defined as `%s`",
 			fnReflectType.String(),
 		)
 		return
@@ -54,16 +54,16 @@ func RegisterConverter(fn interface{}) (err error) {
 	if inType.Kind() == reflect.Pointer {
 		err = gerror.NewCodef(
 			gcode.CodeInvalidParameter,
-			"invalid input parameter type `%s`: should not be type of pointer",
-			inType.String(),
+			"invalid converter function `%s`: invalid input parameter type `%s`, should not be type of pointer",
+			fnReflectType.String(), inType.String(),
 		)
 		return
 	}
 	if outType.Kind() != reflect.Pointer {
 		err = gerror.NewCodef(
 			gcode.CodeInvalidParameter,
-			"invalid output parameter type `%s`: should be type of pointer",
-			outType.String(),
+			"invalid converter function `%s`: invalid output parameter type `%s` should be type of pointer",
+			fnReflectType.String(), outType.String(),
 		)
 		return
 	}
@@ -85,39 +85,69 @@ func RegisterConverter(fn interface{}) (err error) {
 	return
 }
 
-// callCustomConverter call the custom converter. It will try some possible type.
-func callCustomConverter(srcReflectValue reflect.Value, dstReflectValue reflect.Value) (converted bool, err error) {
+func getRegisteredConverterFuncAndSrcType(
+	srcReflectValue, dstReflectValueForRefer reflect.Value,
+) (f converterFunc, srcType reflect.Type, ok bool) {
 	if len(customConverters) == 0 {
-		return false, nil
+		return reflect.Value{}, nil, false
 	}
-	var (
-		ok      bool
-		srcType = srcReflectValue.Type()
-	)
+	srcType = srcReflectValue.Type()
 	for srcType.Kind() == reflect.Pointer {
 		srcType = srcType.Elem()
 	}
-	var (
-		registeredOutTypeMap    map[converterOutType]converterFunc
-		registeredConverterFunc converterFunc
-	)
+	var registeredOutTypeMap map[converterOutType]converterFunc
 	// firstly, it searches the map by input parameter type.
 	registeredOutTypeMap, ok = customConverters[srcType]
 	if !ok {
-		return false, nil
+		return reflect.Value{}, nil, false
 	}
-	var dstType = dstReflectValue.Type()
-	if dstType.Kind() == reflect.Pointer && dstReflectValue.Elem().Kind() == reflect.Pointer {
-		dstType = dstReflectValue.Elem().Type()
-	} else if dstType.Kind() != reflect.Pointer && dstReflectValue.CanAddr() {
-		dstType = dstReflectValue.Addr().Type()
+	var dstType = dstReflectValueForRefer.Type()
+	if dstType.Kind() == reflect.Pointer {
+		// Might be **struct, which is support as designed.
+		if dstType.Elem().Kind() == reflect.Pointer {
+			dstType = dstType.Elem()
+		}
+	} else if dstReflectValueForRefer.IsValid() && dstReflectValueForRefer.CanAddr() {
+		dstType = dstReflectValueForRefer.Addr().Type()
+	} else {
+		dstType = reflect.PointerTo(dstType)
 	}
 	// secondly, it searches the input parameter type map
 	// and finds the result converter function by the output parameter type.
-	registeredConverterFunc, ok = registeredOutTypeMap[dstType]
+	f, ok = registeredOutTypeMap[dstType]
+	if !ok {
+		return reflect.Value{}, nil, false
+	}
+	return
+}
+
+func callCustomConverterWithRefer(
+	srcReflectValue, referReflectValue reflect.Value,
+) (dstReflectValue reflect.Value, converted bool, err error) {
+	registeredConverterFunc, srcType, ok := getRegisteredConverterFuncAndSrcType(srcReflectValue, referReflectValue)
+	if !ok {
+		return reflect.Value{}, false, nil
+	}
+	dstReflectValue = reflect.New(referReflectValue.Type()).Elem()
+	converted, err = doCallCustomConverter(srcReflectValue, dstReflectValue, registeredConverterFunc, srcType)
+	return
+}
+
+// callCustomConverter call the custom converter. It will try some possible type.
+func callCustomConverter(srcReflectValue, dstReflectValue reflect.Value) (converted bool, err error) {
+	registeredConverterFunc, srcType, ok := getRegisteredConverterFuncAndSrcType(srcReflectValue, dstReflectValue)
 	if !ok {
 		return false, nil
 	}
+	return doCallCustomConverter(srcReflectValue, dstReflectValue, registeredConverterFunc, srcType)
+}
+
+func doCallCustomConverter(
+	srcReflectValue reflect.Value,
+	dstReflectValue reflect.Value,
+	registeredConverterFunc converterFunc,
+	srcType reflect.Type,
+) (converted bool, err error) {
 	// Converter function calling.
 	for srcReflectValue.Type() != srcType {
 		srcReflectValue = srcReflectValue.Elem()

util/gconv/gconv_z_unit_converter_test.go

@@ -16,6 +16,52 @@ import (
 	"github.com/gogf/gf/v2/util/gconv"
 )
 
+func TestConverter_ConvertWithRefer(t *testing.T) {
+	type tA struct {
+		Val int
+	}
+
+	type tB struct {
+		Val1 int32
+		Val2 string
+	}
+
+	gtest.C(t, func(t *gtest.T) {
+		err := gconv.RegisterConverter(func(a tA) (b *tB, err error) {
+			b = &tB{
+				Val1: int32(a.Val),
+				Val2: "abcd",
+			}
+			return
+		})
+		t.AssertNil(err)
+	})
+
+	gtest.C(t, func(t *gtest.T) {
+		a := &tA{
+			Val: 1,
+		}
+		var b tB
+		result := gconv.ConvertWithRefer(a, &b)
+		t.Assert(result.(*tB), &tB{
+			Val1: 1,
+			Val2: "abcd",
+		})
+	})
+
+	gtest.C(t, func(t *gtest.T) {
+		a := &tA{
+			Val: 1,
+		}
+		var b tB
+		result := gconv.ConvertWithRefer(a, b)
+		t.Assert(result.(tB), tB{
+			Val1: 1,
+			Val2: "abcd",
+		})
+	})
+}
+
 func TestConverter_Struct(t *testing.T) {
 	type tA struct {
 		Val int