router.go

// Copyright 2015-2019 HenryLee. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package erpc

import (
	"path"
	"reflect"
	"runtime"
	"strings"
	"sync"
	"unsafe"

	"github.com/henrylee2cn/goutil"
	"github.com/henrylee2cn/goutil/errors"
)

// ServiceMethodMapper mapper service method from prefix, recvName and funcName.
// NOTE:
//  @prefix is optional;
//  @name is required.
type ServiceMethodMapper func(prefix, name string) (serviceMethod string)

// SetServiceMethodMapper customizes your own service method mapper.
func SetServiceMethodMapper(mapper ServiceMethodMapper) {
	globalServiceMethodMapper = mapper
}

// HTTPServiceMethodMapper like most RPC services service method mapper.
// Such as: user/get
// It is the default mapper.
// The mapping rule of struct(func) name to service methods:
//  `AaBb` -> `/aa_bb`
//  `ABcXYz` -> `/abc_xyz`
//  `Aa__Bb` -> `/aa_bb`
//  `aa__bb` -> `/aa_bb`
//  `ABC__XYZ` -> `/abc_xyz`
//  `Aa_Bb` -> `/aa/bb`
//  `aa_bb` -> `/aa/bb`
//  `ABC_XYZ` -> `/abc/xyz`
//
func HTTPServiceMethodMapper(prefix, name string) string {
	return path.Join("/", prefix, toServiceMethods(name, '/', true))
}

// RPCServiceMethodMapper like most RPC services service method mapper.
// Such as: User.Get
// The mapping rule of struct(func) name to service methods:
//  `AaBb` -> `AaBb`
//  `ABcXYz` -> `ABcXYz`
//  `Aa__Bb` -> `Aa_Bb`
//  `aa__bb` -> `aa_bb`
//  `ABC__XYZ` -> `ABC_XYZ`
//  `Aa_Bb` -> `Aa.Bb`
//  `aa_bb` -> `aa.bb`
//  `ABC_XYZ` -> `ABC.XYZ`
//
func RPCServiceMethodMapper(prefix, name string) string {
	p := prefix + "." + toServiceMethods(name, '.', false)
	return strings.Trim(p, ".")
}

// toServiceMethods maps struct(func) name to service methods.
func toServiceMethods(name string, sep rune, toSnake bool) string {
	var a = []rune{}
	var last rune
	for _, r := range name {
		if last == '_' {
			if r == '_' {
				last = '\x00'
				continue
			} else {
				a[len(a)-1] = sep
			}
		}
		if last == '\x00' && r == '_' {
			continue
		}
		a = append(a, r)
		last = r
	}
	name = string(a)
	if toSnake {
		name = goutil.SnakeString(name)
		name = strings.Replace(name, "__", "_", -1)
		name = strings.Replace(name, string(sep)+"_", string(sep), -1)
	}
	return name
}

/**
 * Router the router of call or push handlers.
 *
 * 1. Call-Controller-Struct API template
 *
 *  type Aaa struct {
 *      erpc.CallCtx
 *  }
 *  func (x *Aaa) XxZz(arg *<T>) (<T>, *erpc.Status) {
 *      ...
 *      return r, nil
 *  }
 *
 * - register it to root router:
 *
 *  // register the call route: /aaa/xx_zz
 *  peer.RouteCall(new(Aaa))
 *
 *  // or register the call route: /xx_zz
 *  peer.RouteCallFunc((*Aaa).XxZz)
 *
 * 2. Call-Handler-Function API template
 *
 *  func XxZz(ctx erpc.CallCtx, arg *<T>) (<T>, *erpc.Status) {
 *      ...
 *      return r, nil
 *  }
 *
 * - register it to root router:
 *
 *  // register the call route: /xx_zz
 *  peer.RouteCallFunc(XxZz)
 *
 * 3. Push-Controller-Struct API template
 *
 *  type Bbb struct {
 *      erpc.PushCtx
 *  }
 *  func (b *Bbb) YyZz(arg *<T>) *erpc.Status {
 *      ...
 *      return nil
 *  }
 *
 * - register it to root router:
 *
 *  // register the push route: /bbb/yy_zz
 *  peer.RoutePush(new(Bbb))
 *
 *  // or register the push route: /yy_zz
 *  peer.RoutePushFunc((*Bbb).YyZz)
 *
 * 4. Push-Handler-Function API template
 *
 *  // YyZz register the route: /yy_zz
 *  func YyZz(ctx erpc.PushCtx, arg *<T>) *erpc.Status {
 *      ...
 *      return nil
 *  }
 *
 * - register it to root router:
 *
 *  // register the push route: /yy_zz
 *  peer.RoutePushFunc(YyZz)
 *
 * 5. Unknown-Call-Handler-Function API template
 *
 *  func XxxUnknownCall (ctx erpc.UnknownCallCtx) (interface{}, *erpc.Status) {
 *      ...
 *      return r, nil
 *  }
 *
 * - register it to root router:
 *
 *  // register the unknown call route: /*
 *  peer.SetUnknownCall(XxxUnknownCall)
 *
 * 6. Unknown-Push-Handler-Function API template
 *
 *  func XxxUnknownPush(ctx erpc.UnknownPushCtx) *erpc.Status {
 *      ...
 *      return nil
 *  }
 *
 * - register it to root router:
 *
 *  // register the unknown push route: /*
 *  peer.SetUnknownPush(XxxUnknownPush)
 *
 * 7. The default mapping rule(HTTPServiceMethodMapper) of struct(func) name to service methods:
 *
 * - `AaBb` -> `/aa_bb`
 * - `ABcXYz` -> `/abc_xyz`
 * - `Aa__Bb` -> `/aa_bb`
 * - `aa__bb` -> `/aa_bb`
 * - `ABC__XYZ` -> `/abc_xyz`
 * - `Aa_Bb` -> `/aa/bb`
 * - `aa_bb` -> `/aa/bb`
 * - `ABC_XYZ` -> `/abc/xyz`
 *
 * 8. The mapping rule(RPCServiceMethodMapper) of struct(func) name to service methods:
 *
 * - `AaBb` -> `AaBb`
 * - `ABcXYz` -> `ABcXYz`
 * - `Aa__Bb` -> `Aa_Bb`
 * - `aa__bb` -> `aa_bb`
 * - `ABC__XYZ` -> `ABC_XYZ`
 * - `Aa_Bb` -> `Aa.Bb`
 * - `aa_bb` -> `aa.bb`
 * - `ABC_XYZ` -> `ABC.XYZ`
 **/

type (
	// Router the router of call or push handlers.
	Router struct {
		subRouter *SubRouter
	}
	// SubRouter without the SetUnknownCall and SetUnknownPush methods
	SubRouter struct {
		root         *Router
		callHandlers map[string]*Handler
		pushHandlers map[string]*Handler
		unknownCall  **Handler
		unknownPush  **Handler
		// only for register router
		prefix          string
		pluginContainer *PluginContainer
	}
	// Handler call or push handler type info
	Handler struct {
		name              string
		argElem           reflect.Type
		reply             reflect.Type // only for call handler doc
		handleFunc        func(*handlerCtx, reflect.Value)
		unknownHandleFunc func(*handlerCtx)
		pluginContainer   *PluginContainer
		routerTypeName    string
		isUnknown         bool
	}
	// HandlersMaker makes []*Handler
	HandlersMaker func(string, interface{}, *PluginContainer) ([]*Handler, error)
)

var globalServiceMethodMapper = HTTPServiceMethodMapper

const (
	pnPush        = "PUSH"
	pnCall        = "CALL"
	pnUnknownPush = "UNKNOWN_PUSH"
	pnUnknownCall = "UNKNOWN_CALL"
)

// newRouter creates root router.
func newRouter(pluginContainer *PluginContainer) *Router {
	rootGroup := globalServiceMethodMapper("", "")
	root := &Router{
		subRouter: &SubRouter{
			callHandlers:    make(map[string]*Handler),
			pushHandlers:    make(map[string]*Handler),
			unknownCall:     new(*Handler),
			unknownPush:     new(*Handler),
			prefix:          rootGroup,
			pluginContainer: pluginContainer,
		},
	}
	root.subRouter.root = root
	return root
}

// Root returns the root router.
func (r *SubRouter) Root() *Router {
	return r.root
}

// ToRouter converts to the router which is added the SetUnknownCall and SetUnknownPush methods.
func (r *SubRouter) ToRouter() *Router {
	return &Router{subRouter: r}
}

// SubRoute adds handler group.
func (r *Router) SubRoute(prefix string, plugin ...Plugin) *SubRouter {
	return r.subRouter.SubRoute(prefix, plugin...)
}

// SubRoute adds handler group.
func (r *SubRouter) SubRoute(prefix string, plugin ...Plugin) *SubRouter {
	pluginContainer := r.pluginContainer.cloneAndAppendMiddle(plugin...)
	warnInvaildHandlerHooks(plugin)
	return &SubRouter{
		root:            r.root,
		callHandlers:    r.callHandlers,
		pushHandlers:    r.pushHandlers,
		unknownCall:     r.unknownCall,
		unknownPush:     r.unknownPush,
		prefix:          globalServiceMethodMapper(r.prefix, prefix),
		pluginContainer: pluginContainer,
	}
}

// RouteCall registers CALL handlers, and returns the paths.
func (r *Router) RouteCall(callCtrlStruct interface{}, plugin ...Plugin) []string {
	return r.subRouter.RouteCall(callCtrlStruct, plugin...)
}

// RouteCall registers CALL handlers, and returns the paths.
func (r *SubRouter) RouteCall(callCtrlStruct interface{}, plugin ...Plugin) []string {
	return r.reg(pnCall, makeCallHandlersFromStruct, callCtrlStruct, plugin)
}

// RouteCallFunc registers CALL handler, and returns the path.
func (r *Router) RouteCallFunc(callHandleFunc interface{}, plugin ...Plugin) string {
	return r.subRouter.RouteCallFunc(callHandleFunc, plugin...)
}

// RouteCallFunc registers CALL handler, and returns the path.
func (r *SubRouter) RouteCallFunc(callHandleFunc interface{}, plugin ...Plugin) string {
	return r.reg(pnCall, makeCallHandlersFromFunc, callHandleFunc, plugin)[0]
}

// RoutePush registers PUSH handlers, and returns the paths.
func (r *Router) RoutePush(pushCtrlStruct interface{}, plugin ...Plugin) []string {
	return r.subRouter.RoutePush(pushCtrlStruct, plugin...)
}

// RoutePush registers PUSH handlers, and returns the paths.
func (r *SubRouter) RoutePush(pushCtrlStruct interface{}, plugin ...Plugin) []string {
	return r.reg(pnPush, makePushHandlersFromStruct, pushCtrlStruct, plugin)
}

// RoutePushFunc registers PUSH handler, and returns the path.
func (r *Router) RoutePushFunc(pushHandleFunc interface{}, plugin ...Plugin) string {
	return r.subRouter.RoutePushFunc(pushHandleFunc, plugin...)
}

// RoutePushFunc registers PUSH handler, and returns the path.
func (r *SubRouter) RoutePushFunc(pushHandleFunc interface{}, plugin ...Plugin) string {
	return r.reg(pnPush, makePushHandlersFromFunc, pushHandleFunc, plugin)[0]
}

func (r *SubRouter) reg(
	routerTypeName string,
	handlerMaker func(string, interface{}, *PluginContainer) ([]*Handler, error),
	ctrlStruct interface{},
	plugins []Plugin,
) []string {
	pluginContainer := r.pluginContainer.cloneAndAppendMiddle(plugins...)
	warnInvaildHandlerHooks(plugins)
	handlers, err := handlerMaker(
		r.prefix,
		ctrlStruct,
		pluginContainer,
	)
	if err != nil {
		Fatalf("%v", err)
	}
	var names []string
	var hadHandlers map[string]*Handler
	if routerTypeName == pnCall {
		hadHandlers = r.callHandlers
	} else {
		hadHandlers = r.pushHandlers
	}
	for _, h := range handlers {
		if _, ok := hadHandlers[h.name]; ok {
			Fatalf("there is a handler conflict: %s", h.name)
		}
		h.routerTypeName = routerTypeName
		hadHandlers[h.name] = h
		pluginContainer.postReg(h)
		Printf("register %s handler: %s", routerTypeName, h.name)
		names = append(names, h.name)
	}
	return names
}

// SetUnknownCall sets the default handler,
// which is called when no handler for CALL is found.
func (r *Router) SetUnknownCall(fn func(UnknownCallCtx) (interface{}, *Status), plugin ...Plugin) {
	pluginContainer := r.subRouter.pluginContainer.cloneAndAppendMiddle(plugin...)
	warnInvaildHandlerHooks(plugin)

	var h = &Handler{
		name:            pnUnknownCall,
		isUnknown:       true,
		argElem:         reflect.TypeOf([]byte{}),
		pluginContainer: pluginContainer,
		unknownHandleFunc: func(ctx *handlerCtx) {
			body, stat := fn(ctx)
			if !stat.OK() {
				ctx.stat = stat
				ctx.output.SetStatus(stat)
			} else {
				ctx.output.SetBody(body)
			}
		},
	}

	if *r.subRouter.unknownCall == nil {
		Printf("set %s handler", h.name)
	} else {
		Warnf("covered %s handler", h.name)
	}
	r.subRouter.unknownCall = &h
}

// SetUnknownPush sets the default handler,
// which is called when no handler for PUSH is found.
func (r *Router) SetUnknownPush(fn func(UnknownPushCtx) *Status, plugin ...Plugin) {
	pluginContainer := r.subRouter.pluginContainer.cloneAndAppendMiddle(plugin...)
	warnInvaildHandlerHooks(plugin)

	var h = &Handler{
		name:            pnUnknownPush,
		isUnknown:       true,
		argElem:         reflect.TypeOf([]byte{}),
		pluginContainer: pluginContainer,
		unknownHandleFunc: func(ctx *handlerCtx) {
			ctx.stat = fn(ctx)
		},
	}

	if *r.subRouter.unknownPush == nil {
		Printf("set %s handler", h.name)
	} else {
		Warnf("covered %s handler", h.name)
	}
	r.subRouter.unknownPush = &h
}

func (r *SubRouter) getCall(uriPath string) (*Handler, bool) {
	t, ok := r.callHandlers[uriPath]
	if ok {
		return t, true
	}
	if unknown := *r.unknownCall; unknown != nil {
		return unknown, true
	}
	return nil, false
}

func (r *SubRouter) getPush(uriPath string) (*Handler, bool) {
	t, ok := r.pushHandlers[uriPath]
	if ok {
		return t, true
	}
	if unknown := *r.unknownPush; unknown != nil {
		return unknown, true
	}
	return nil, false
}

// NOTE: callCtrlStruct needs to implement CallCtx interface.
func makeCallHandlersFromStruct(prefix string, callCtrlStruct interface{}, pluginContainer *PluginContainer) ([]*Handler, error) {
	var (
		ctype    = reflect.TypeOf(callCtrlStruct)
		handlers = make([]*Handler, 0, 1)
	)

	if ctype.Kind() != reflect.Ptr {
		return nil, errors.Errorf("call-handler: the type is not struct point: %s", ctype.String())
	}

	var ctypeElem = ctype.Elem()
	if ctypeElem.Kind() != reflect.Struct {
		return nil, errors.Errorf("call-handler: the type is not struct point: %s", ctype.String())
	}

	iType, ok := ctypeElem.FieldByName("CallCtx")
	if !ok || !iType.Anonymous {
		return nil, errors.Errorf("call-handler: the struct do not have anonymous field erpc.CallCtx: %s", ctype.String())
	}

	var callCtxOffset = iType.Offset

	if pluginContainer == nil {
		pluginContainer = newPluginContainer()
	}

	type CallCtrlValue struct {
		ctrl   reflect.Value
		ctxPtr *CallCtx
	}
	var pool = &sync.Pool{
		New: func() interface{} {
			ctrl := reflect.New(ctypeElem)
			callCtxPtr := ctrl.Pointer() + callCtxOffset
			ctxPtr := (*CallCtx)(unsafe.Pointer(callCtxPtr))
			return &CallCtrlValue{
				ctrl:   ctrl,
				ctxPtr: ctxPtr,
			}
		},
	}

	for m := 0; m < ctype.NumMethod(); m++ {
		method := ctype.Method(m)
		mtype := method.Type
		mname := method.Name
		// Method must be exported.
		if method.PkgPath != "" {
			continue
		}
		// Method needs two ins: receiver, *<T>.
		if mtype.NumIn() != 2 {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("call-handler: %s.%s needs one in argument, but have %d", ctype.String(), mname, mtype.NumIn())
		}
		// Receiver need be a struct pointer.
		structType := mtype.In(0)
		if structType.Kind() != reflect.Ptr || structType.Elem().Kind() != reflect.Struct {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("call-handler: %s.%s receiver need be a struct pointer: %s", ctype.String(), mname, structType)
		}
		// First arg need be exported or builtin, and need be a pointer.
		argType := mtype.In(1)
		if !goutil.IsExportedOrBuiltinType(argType) {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("call-handler: %s.%s arg type not exported: %s", ctype.String(), mname, argType)
		}
		if argType.Kind() != reflect.Ptr {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("call-handler: %s.%s arg type need be a pointer: %s", ctype.String(), mname, argType)
		}
		// Method needs two outs: reply, *Status.
		if mtype.NumOut() != 2 {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("call-handler: %s.%s needs two out arguments, but have %d", ctype.String(), mname, mtype.NumOut())
		}
		// Reply type must be exported.
		replyType := mtype.Out(0)
		if !goutil.IsExportedOrBuiltinType(replyType) {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("call-handler: %s.%s first reply type not exported: %s", ctype.String(), mname, replyType)
		}

		// The return type of the method must be *Status.
		if returnType := mtype.Out(1); !isStatusType(returnType.String()) {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("call-handler: %s.%s second out argument %s is not *erpc.Status", ctype.String(), mname, returnType)
		}

		var methodFunc = method.Func
		var handleFunc = func(ctx *handlerCtx, argValue reflect.Value) {
			obj := pool.Get().(*CallCtrlValue)
			*obj.ctxPtr = ctx
			rets := methodFunc.Call([]reflect.Value{obj.ctrl, argValue})
			stat := (*Status)(unsafe.Pointer(rets[1].Pointer()))
			if !stat.OK() {
				ctx.stat = stat
				ctx.output.SetStatus(stat)
			} else {
				ctx.output.SetBody(rets[0].Interface())
			}
			pool.Put(obj)
		}

		handlers = append(handlers, &Handler{
			handleFunc:      handleFunc,
			argElem:         argType.Elem(),
			reply:           replyType,
			pluginContainer: pluginContainer,
			name: globalServiceMethodMapper(
				globalServiceMethodMapper(prefix, ctrlStructName(ctype)),
				mname,
			),
		})
	}
	return handlers, nil
}

func makeCallHandlersFromFunc(prefix string, callHandleFunc interface{}, pluginContainer *PluginContainer) ([]*Handler, error) {
	var (
		ctype      = reflect.TypeOf(callHandleFunc)
		cValue     = reflect.ValueOf(callHandleFunc)
		typeString = objectName(cValue)
	)

	if ctype.Kind() != reflect.Func {
		return nil, errors.Errorf("call-handler: the type is not function: %s", typeString)
	}

	// needs two outs: reply, *Status.
	if ctype.NumOut() != 2 {
		return nil, errors.Errorf("call-handler: %s needs two out arguments, but have %d", typeString, ctype.NumOut())
	}

	// Reply type must be exported.
	replyType := ctype.Out(0)
	if !goutil.IsExportedOrBuiltinType(replyType) {
		return nil, errors.Errorf("call-handler: %s first reply type not exported: %s", typeString, replyType)
	}

	// The return type of the method must be *Status.
	if returnType := ctype.Out(1); !isStatusType(returnType.String()) {
		return nil, errors.Errorf("call-handler: %s second out argument %s is not *erpc.Status", typeString, returnType)
	}

	// needs two ins: CallCtx, *<T>.
	if ctype.NumIn() != 2 {
		return nil, errors.Errorf("call-handler: %s needs two in argument, but have %d", typeString, ctype.NumIn())
	}

	// First arg need be exported or builtin, and need be a pointer.
	argType := ctype.In(1)
	if !goutil.IsExportedOrBuiltinType(argType) {
		return nil, errors.Errorf("call-handler: %s arg type not exported: %s", typeString, argType)
	}
	if argType.Kind() != reflect.Ptr {
		return nil, errors.Errorf("call-handler: %s arg type need be a pointer: %s", typeString, argType)
	}

	// first agr need be a CallCtx (struct pointer or CallCtx).
	ctxType := ctype.In(0)

	var handleFunc func(*handlerCtx, reflect.Value)

	switch ctxType.Kind() {
	default:
		return nil, errors.Errorf("call-handler: %s's first arg must be erpc.CallCtx type or struct pointer: %s", typeString, ctxType)

	case reflect.Interface:
		iface := reflect.TypeOf((*CallCtx)(nil)).Elem()
		if !ctxType.Implements(iface) ||
			!iface.Implements(reflect.New(ctxType).Type().Elem()) {
			return nil, errors.Errorf("call-handler: %s's first arg must be erpc.CallCtx type or struct pointer: %s", typeString, ctxType)
		}

		handleFunc = func(ctx *handlerCtx, argValue reflect.Value) {
			rets := cValue.Call([]reflect.Value{reflect.ValueOf(ctx), argValue})
			stat := (*Status)(unsafe.Pointer(rets[1].Pointer()))
			if !stat.OK() {
				ctx.stat = stat
				ctx.output.SetStatus(stat)
			} else {
				ctx.output.SetBody(rets[0].Interface())
			}
		}

	case reflect.Ptr:
		var ctxTypeElem = ctxType.Elem()
		if ctxTypeElem.Kind() != reflect.Struct {
			return nil, errors.Errorf("call-handler: %s's first arg must be erpc.CallCtx type or struct pointer: %s", typeString, ctxType)
		}

		iType, ok := ctxTypeElem.FieldByName("CallCtx")
		if !ok || !iType.Anonymous {
			return nil, errors.Errorf("call-handler: %s's first arg do not have anonymous field erpc.CallCtx: %s", typeString, ctxType)
		}

		type CallCtrlValue struct {
			ctrl   reflect.Value
			ctxPtr *CallCtx
		}
		var callCtxOffset = iType.Offset
		var pool = &sync.Pool{
			New: func() interface{} {
				ctrl := reflect.New(ctxTypeElem)
				callCtxPtr := ctrl.Pointer() + callCtxOffset
				ctxPtr := (*CallCtx)(unsafe.Pointer(callCtxPtr))
				return &CallCtrlValue{
					ctrl:   ctrl,
					ctxPtr: ctxPtr,
				}
			},
		}

		handleFunc = func(ctx *handlerCtx, argValue reflect.Value) {
			obj := pool.Get().(*CallCtrlValue)
			*obj.ctxPtr = ctx
			rets := cValue.Call([]reflect.Value{obj.ctrl, argValue})
			stat := (*Status)(unsafe.Pointer(rets[1].Pointer()))
			if !stat.OK() {
				ctx.stat = stat
				ctx.output.SetStatus(stat)
			} else {
				ctx.output.SetBody(rets[0].Interface())
			}
			pool.Put(obj)
		}
	}

	if pluginContainer == nil {
		pluginContainer = newPluginContainer()
	}
	return []*Handler{&Handler{
		name:            globalServiceMethodMapper(prefix, handlerFuncName(cValue)),
		handleFunc:      handleFunc,
		argElem:         argType.Elem(),
		reply:           replyType,
		pluginContainer: pluginContainer,
	}}, nil
}

// NOTE: pushCtrlStruct needs to implement PushCtx interface.
func makePushHandlersFromStruct(prefix string, pushCtrlStruct interface{}, pluginContainer *PluginContainer) ([]*Handler, error) {
	var (
		ctype    = reflect.TypeOf(pushCtrlStruct)
		handlers = make([]*Handler, 0, 1)
	)

	if ctype.Kind() != reflect.Ptr {
		return nil, errors.Errorf("push-handler: the type is not struct point: %s", ctype.String())
	}

	var ctypeElem = ctype.Elem()
	if ctypeElem.Kind() != reflect.Struct {
		return nil, errors.Errorf("push-handler: the type is not struct point: %s", ctype.String())
	}

	iType, ok := ctypeElem.FieldByName("PushCtx")
	if !ok || !iType.Anonymous {
		return nil, errors.Errorf("push-handler: the struct do not have anonymous field erpc.PushCtx: %s", ctype.String())
	}

	var pushCtxOffset = iType.Offset

	if pluginContainer == nil {
		pluginContainer = newPluginContainer()
	}
	type PushCtrlValue struct {
		ctrl   reflect.Value
		ctxPtr *PushCtx
	}
	var pool = &sync.Pool{
		New: func() interface{} {
			ctrl := reflect.New(ctypeElem)
			pushCtxPtr := ctrl.Pointer() + pushCtxOffset
			ctxPtr := (*PushCtx)(unsafe.Pointer(pushCtxPtr))
			return &PushCtrlValue{
				ctrl:   ctrl,
				ctxPtr: ctxPtr,
			}
		},
	}

	for m := 0; m < ctype.NumMethod(); m++ {
		method := ctype.Method(m)
		mtype := method.Type
		mname := method.Name
		// Method must be exported.
		if method.PkgPath != "" {
			continue
		}
		// Method needs two ins: receiver, *<T>.
		if mtype.NumIn() != 2 {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("push-handler: %s.%s needs one in argument, but have %d", ctype.String(), mname, mtype.NumIn())
		}
		// Receiver need be a struct pointer.
		structType := mtype.In(0)
		if structType.Kind() != reflect.Ptr || structType.Elem().Kind() != reflect.Struct {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("push-handler: %s.%s receiver need be a struct pointer: %s", ctype.String(), mname, structType)
		}
		// First arg need be exported or builtin, and need be a pointer.
		argType := mtype.In(1)
		if !goutil.IsExportedOrBuiltinType(argType) {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("push-handler: %s.%s arg type not exported: %s", ctype.String(), mname, argType)
		}
		if argType.Kind() != reflect.Ptr {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("push-handler: %s.%s arg type need be a pointer: %s", ctype.String(), mname, argType)
		}

		// Method needs one out: *Status.
		if mtype.NumOut() != 1 {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("push-handler: %s.%s needs one out arguments, but have %d", ctype.String(), mname, mtype.NumOut())
		}

		// The return type of the method must be *Status.
		if returnType := mtype.Out(0); !isStatusType(returnType.String()) {
			if isBelongToCallCtx(mname) {
				continue
			}
			return nil, errors.Errorf("push-handler: %s.%s out argument %s is not *erpc.Status", ctype.String(), mname, returnType)
		}

		var methodFunc = method.Func
		var handleFunc = func(ctx *handlerCtx, argValue reflect.Value) {
			obj := pool.Get().(*PushCtrlValue)
			*obj.ctxPtr = ctx
			rets := methodFunc.Call([]reflect.Value{obj.ctrl, argValue})
			ctx.stat = (*Status)(unsafe.Pointer(rets[0].Pointer()))
			pool.Put(obj)
		}
		handlers = append(handlers, &Handler{
			handleFunc:      handleFunc,
			argElem:         argType.Elem(),
			pluginContainer: pluginContainer,
			name: globalServiceMethodMapper(
				globalServiceMethodMapper(prefix, ctrlStructName(ctype)),
				mname,
			),
		})
	}
	return handlers, nil
}

func makePushHandlersFromFunc(prefix string, pushHandleFunc interface{}, pluginContainer *PluginContainer) ([]*Handler, error) {
	var (
		ctype      = reflect.TypeOf(pushHandleFunc)
		cValue     = reflect.ValueOf(pushHandleFunc)
		typeString = objectName(cValue)
	)

	if ctype.Kind() != reflect.Func {
		return nil, errors.Errorf("push-handler: the type is not function: %s", typeString)
	}

	// needs one out: *Status.
	if ctype.NumOut() != 1 {
		return nil, errors.Errorf("push-handler: %s needs one out arguments, but have %d", typeString, ctype.NumOut())
	}

	// The return type of the method must be *Status.
	if returnType := ctype.Out(0); !isStatusType(returnType.String()) {
		return nil, errors.Errorf("push-handler: %s out argument %s is not *erpc.Status", typeString, returnType)
	}

	// needs two ins: PushCtx, *<T>.
	if ctype.NumIn() != 2 {
		return nil, errors.Errorf("push-handler: %s needs two in argument, but have %d", typeString, ctype.NumIn())
	}

	// First arg need be exported or builtin, and need be a pointer.
	argType := ctype.In(1)
	if !goutil.IsExportedOrBuiltinType(argType) {
		return nil, errors.Errorf("push-handler: %s arg type not exported: %s", typeString, argType)
	}
	if argType.Kind() != reflect.Ptr {
		return nil, errors.Errorf("push-handler: %s arg type need be a pointer: %s", typeString, argType)
	}

	// first agr need be a PushCtx (struct pointer or PushCtx).
	ctxType := ctype.In(0)

	var handleFunc func(*handlerCtx, reflect.Value)

	switch ctxType.Kind() {
	default:
		return nil, errors.Errorf("push-handler: %s's first arg must be erpc.PushCtx type or struct pointer: %s", typeString, ctxType)

	case reflect.Interface:
		iface := reflect.TypeOf((*PushCtx)(nil)).Elem()
		if !ctxType.Implements(iface) ||
			!iface.Implements(reflect.New(ctxType).Type().Elem()) {
			return nil, errors.Errorf("push-handler: %s's first arg need implement erpc.PushCtx: %s", typeString, ctxType)
		}

		handleFunc = func(ctx *handlerCtx, argValue reflect.Value) {
			rets := cValue.Call([]reflect.Value{reflect.ValueOf(ctx), argValue})
			ctx.stat = (*Status)(unsafe.Pointer(rets[0].Pointer()))
		}

	case reflect.Ptr:
		var ctxTypeElem = ctxType.Elem()
		if ctxTypeElem.Kind() != reflect.Struct {
			return nil, errors.Errorf("push-handler: %s's first arg must be erpc.PushCtx type or struct pointer: %s", typeString, ctxType)
		}

		iType, ok := ctxTypeElem.FieldByName("PushCtx")
		if !ok || !iType.Anonymous {
			return nil, errors.Errorf("push-handler: %s's first arg do not have anonymous field erpc.PushCtx: %s", typeString, ctxType)
		}

		type PushCtrlValue struct {
			ctrl   reflect.Value
			ctxPtr *PushCtx
		}
		var pushCtxOffset = iType.Offset
		var pool = &sync.Pool{
			New: func() interface{} {
				ctrl := reflect.New(ctxTypeElem)
				pushCtxPtr := ctrl.Pointer() + pushCtxOffset
				ctxPtr := (*PushCtx)(unsafe.Pointer(pushCtxPtr))
				return &PushCtrlValue{
					ctrl:   ctrl,
					ctxPtr: ctxPtr,
				}
			},
		}

		handleFunc = func(ctx *handlerCtx, argValue reflect.Value) {
			obj := pool.Get().(*PushCtrlValue)
			*obj.ctxPtr = ctx
			rets := cValue.Call([]reflect.Value{obj.ctrl, argValue})
			ctx.stat = (*Status)(unsafe.Pointer(rets[0].Pointer()))
			pool.Put(obj)
		}
	}

	if pluginContainer == nil {
		pluginContainer = newPluginContainer()
	}
	return []*Handler{&Handler{
		name:            globalServiceMethodMapper(prefix, handlerFuncName(cValue)),
		handleFunc:      handleFunc,
		argElem:         argType.Elem(),
		pluginContainer: pluginContainer,
	}}, nil
}

func isBelongToCallCtx(name string) bool {
	ctype := reflect.TypeOf(CallCtx(new(handlerCtx)))
	for m := 0; m < ctype.NumMethod(); m++ {
		if name == ctype.Method(m).Name {
			return true
		}
	}
	return false
}

func isBelongToPushCtx(name string) bool {
	ctype := reflect.TypeOf(PushCtx(new(handlerCtx)))
	for m := 0; m < ctype.NumMethod(); m++ {
		if name == ctype.Method(m).Name {
			return true
		}
	}
	return false
}

func isStatusType(s string) bool {
	return strings.HasPrefix(s, "*") && strings.HasSuffix(s, ".Status")
}

func ctrlStructName(ctype reflect.Type) string {
	split := strings.Split(ctype.String(), ".")
	return split[len(split)-1]
}

func handlerFuncName(v reflect.Value) string {
	str := objectName(v)
	split := strings.Split(str, ".")
	return split[len(split)-1]
}

func objectName(v reflect.Value) string {
	t := v.Type()
	if t.Kind() == reflect.Func {
		return runtime.FuncForPC(v.Pointer()).Name()
	}
	return t.String()
}

// Name returns the handler name.
func (h *Handler) Name() string {
	return h.name
}

// ArgElemType returns the handler arg elem type.
func (h *Handler) ArgElemType() reflect.Type {
	return h.argElem
}

// NewArgValue creates a new arg elem value.
func (h *Handler) NewArgValue() reflect.Value {
	return reflect.New(h.argElem)
}

// ReplyType returns the handler reply type
func (h *Handler) ReplyType() reflect.Type {
	return h.reply
}

// IsCall checks if it is call handler or not.
func (h *Handler) IsCall() bool {
	return h.routerTypeName == pnCall || h.routerTypeName == pnUnknownCall
}

// IsPush checks if it is push handler or not.
func (h *Handler) IsPush() bool {
	return h.routerTypeName == pnPush || h.routerTypeName == pnUnknownPush
}

// IsUnknown checks if it is unknown handler(call/push) or not.
func (h *Handler) IsUnknown() bool {
	return h.isUnknown
}

// RouterTypeName returns the router type name.
func (h *Handler) RouterTypeName() string {
	return h.routerTypeName
}