refactor bind functions based on generics (#22055)

Author: lunny

Diff for: modules/web/route.go

@@ -7,7 +7,6 @@ import (
 	goctx "context"
 	"fmt"
 	"net/http"
-	"reflect"
 	"strings"
 
 	"code.gitea.io/gitea/modules/context"
@@ -18,16 +17,9 @@ import (
 )
 
 // Bind binding an obj to a handler
-func Bind(obj interface{}) http.HandlerFunc {
-	tp := reflect.TypeOf(obj)
-	if tp.Kind() == reflect.Ptr {
-		tp = tp.Elem()
-	}
-	if tp.Kind() != reflect.Struct {
-		panic("Only structs are allowed to bind")
-	}
+func Bind[T any](obj T) http.HandlerFunc {
 	return Wrap(func(ctx *context.Context) {
-		theObj := reflect.New(tp).Interface() // create a new form obj for every request but not use obj directly
+		theObj := new(T) // create a new form obj for every request but not use obj directly
 		binding.Bind(ctx.Req, theObj)
 		SetForm(ctx, theObj)
 		middleware.AssignForm(theObj, ctx.Data)

Diff for: routers/api/v1/api.go

@@ -67,7 +67,6 @@ import (
 	gocontext "context"
 	"fmt"
 	"net/http"
-	"reflect"
 	"strings"
 
 	"code.gitea.io/gitea/models/organization"
@@ -575,13 +574,9 @@ func mustEnableAttachments(ctx *context.APIContext) {
 }
 
 // bind binding an obj to a func(ctx *context.APIContext)
-func bind(obj interface{}) http.HandlerFunc {
-	tp := reflect.TypeOf(obj)
-	for tp.Kind() == reflect.Ptr {
-		tp = tp.Elem()
-	}
+func bind[T any](obj T) http.HandlerFunc {
 	return web.Wrap(func(ctx *context.APIContext) {
-		theObj := reflect.New(tp).Interface() // create a new form obj for every request but not use obj directly
+		theObj := new(T) // create a new form obj for every request but not use obj directly
 		errs := binding.Bind(ctx.Req, theObj)
 		if len(errs) > 0 {
 			ctx.Error(http.StatusUnprocessableEntity, "validationError", fmt.Sprintf("%s: %s", errs[0].FieldNames, errs[0].Error()))

Diff for: routers/private/internal.go

@@ -6,7 +6,6 @@ package private
 
 import (
 	"net/http"
-	"reflect"
 	"strings"
 
 	"code.gitea.io/gitea/modules/context"
@@ -39,13 +38,9 @@ func CheckInternalToken(next http.Handler) http.Handler {
 }
 
 // bind binding an obj to a handler
-func bind(obj interface{}) http.HandlerFunc {
-	tp := reflect.TypeOf(obj)
-	for tp.Kind() == reflect.Ptr {
-		tp = tp.Elem()
-	}
+func bind[T any](obj T) http.HandlerFunc {
 	return web.Wrap(func(ctx *context.PrivateContext) {
-		theObj := reflect.New(tp).Interface() // create a new form obj for every request but not use obj directly
+		theObj := new(T) // create a new form obj for every request but not use obj directly
 		binding.Bind(ctx.Req, theObj)
 		web.SetForm(ctx, theObj)
 	})