#165 support registering raw functions

server/plugin.go

@@ -16,6 +16,7 @@ type PluginContainer interface {
 	All() []Plugin
 
 	DoRegister(name string, rcvr interface{}, metadata string) error
+	DoRegisterFunction(name string, fn interface{}, metadata string) error
 
 	DoPostConnAccept(net.Conn) (net.Conn, bool)
 
@@ -36,6 +37,11 @@ type (
 		Register(name string, rcvr interface{}, metadata string) error
 	}
 
+	// RegisterFunctionPlugin is .
+	RegisterFunctionPlugin interface {
+		RegisterFunction(name string, fn interface{}, metadata string) error
+	}
+
 	// PostConnAcceptPlugin represents connection accept plugin.
 	// if returns false, it means subsequent IPostConnAcceptPlugins should not contiune to handle this conn
 	// and this conn has been closed.
@@ -112,6 +118,24 @@ func (p *pluginContainer) DoRegister(name string, rcvr interface{}, metadata str
 	return nil
 }
 
+// DoRegisterFunction invokes DoRegisterFunction plugin.
+func (p *pluginContainer) DoRegisterFunction(name string, fn interface{}, metadata string) error {
+	var es []error
+	for _, rp := range p.plugins {
+		if plugin, ok := rp.(RegisterFunctionPlugin); ok {
+			err := plugin.RegisterFunction(name, fn, metadata)
+			if err != nil {
+				es = append(es, err)
+			}
+		}
+	}
+
+	if len(es) > 0 {
+		return errors.NewMultiError(es)
+	}
+	return nil
+}
+
 //DoPostConnAccept handles accepted conn
 func (p *pluginContainer) DoPostConnAccept(conn net.Conn) (net.Conn, bool) {
 	var flag bool

server/server.go

@@ -347,14 +347,15 @@ func (s *Server) auth(ctx context.Context, req *protocol.Message) error {
 }
 
 func (s *Server) handleRequest(ctx context.Context, req *protocol.Message) (res *protocol.Message, err error) {
-	// pool res?
+	serviceName := req.ServicePath
+	if serviceName == "" {
+		return s.handleRequestForFunction(ctx, req)
+	}
+	methodName := req.ServiceMethod
+
 	res = req.Clone()
 
 	res.SetMessageType(protocol.Response)
-
-	serviceName := req.ServicePath
-	methodName := req.ServiceMethod
-
 	s.serviceMapMu.RLock()
 	service := s.serviceMap[serviceName]
 	s.serviceMapMu.RUnlock()
@@ -412,6 +413,69 @@ func (s *Server) handleRequest(ctx context.Context, req *protocol.Message) (res
 	return res, nil
 }
 
+func (s *Server) handleRequestForFunction(ctx context.Context, req *protocol.Message) (res *protocol.Message, err error) {
+	res = req.Clone()
+
+	res.SetMessageType(protocol.Response)
+
+	methodName := req.ServiceMethod
+	s.serviceMapMu.RLock()
+	service := s.serviceMap[""]
+	s.serviceMapMu.RUnlock()
+	if service == nil {
+		err = errors.New("rpcx: can't find service func raw function")
+		return handleError(res, err)
+	}
+	mtype := service.function[methodName]
+	if mtype == nil {
+		err = errors.New("rpcx: can't find method " + methodName)
+		return handleError(res, err)
+	}
+
+	var argv, replyv reflect.Value
+
+	argIsValue := false // if true, need to indirect before calling.
+	if mtype.ArgType.Kind() == reflect.Ptr {
+		argv = reflect.New(mtype.ArgType.Elem())
+	} else {
+		argv = reflect.New(mtype.ArgType)
+		argIsValue = true
+	}
+
+	codec := share.Codecs[req.SerializeType()]
+	if codec == nil {
+		err = fmt.Errorf("can not find codec for %d", req.SerializeType())
+		return handleError(res, err)
+	}
+
+	err = codec.Decode(req.Payload, argv.Interface())
+	if err != nil {
+		return handleError(res, err)
+	}
+
+	if argIsValue {
+		argv = argv.Elem()
+	}
+
+	replyv = reflect.New(mtype.ReplyType.Elem())
+
+	err = service.callForFunction(ctx, mtype, argv, replyv)
+	if err != nil {
+		return handleError(res, err)
+	}
+
+	if !req.IsOneway() {
+		data, err := codec.Encode(replyv.Interface())
+		if err != nil {
+			return handleError(res, err)
+
+		}
+		res.Payload = data
+	}
+
+	return res, nil
+}
+
 func handleError(res *protocol.Message, err error) (*protocol.Message, error) {
 	res.SetMessageStatusType(protocol.Error)
 	if res.Metadata == nil {

server/service.go

@@ -19,6 +19,8 @@ var typeOfError = reflect.TypeOf((*error)(nil)).Elem()
 // Precompute the reflect type for context.
 var typeOfContext = reflect.TypeOf((*context.Context)(nil)).Elem()
 
+var emptyService = new(service)
+
 type methodType struct {
 	sync.Mutex // protects counters
 	method     reflect.Method
@@ -27,11 +29,20 @@ type methodType struct {
 	numCalls   uint
 }
 
+type functionType struct {
+	sync.Mutex // protects counters
+	fn         reflect.Value
+	ArgType    reflect.Type
+	ReplyType  reflect.Type
+	numCalls   uint
+}
+
 type service struct {
 	name     string                   // name of service
 	rcvr     reflect.Value            // receiver of methods for the service
 	typ      reflect.Type             // type of the receiver
 	method   map[string]*methodType   // registered methods
+	function map[string]*functionType // registered functions
 }
 
 func isExported(name string) bool {
@@ -51,7 +62,7 @@ func isExportedOrBuiltinType(t reflect.Type) bool {
 // Register publishes in the server the set of methods of the
 // receiver value that satisfy the following conditions:
 //	- exported method of exported type
-//	- three arguments, the first is of context.Context, both of exported type or three arguments
+//	- three arguments, the first is of context.Context, both of exported type for three arguments
 //	- the third argument is a pointer
 //	- one return value, of type error
 // It returns an error if the receiver is not an exported type or has
@@ -59,6 +70,7 @@ func isExportedOrBuiltinType(t reflect.Type) bool {
 // The client accesses each method using a string of the form "Type.Method",
 // where Type is the receiver's concrete type.
 func (s *Server) Register(rcvr interface{}, metadata string) error {
+	s.Plugins.DoRegister("", rcvr, metadata)
 	return s.register(rcvr, "", false)
 }
 
@@ -73,6 +85,28 @@ func (s *Server) RegisterName(name string, rcvr interface{}, metadata string) er
 	return s.register(rcvr, name, true)
 }
 
+// RegisterFunction publishes a function that satisfy the following conditions:
+//	- three arguments, the first is of context.Context, both of exported type for three arguments
+//	- the third argument is a pointer
+//	- one return value, of type error
+// The client accesses function using a string of the form ".Method",
+// where service path is empty.
+func (s *Server) RegisterFunction(fn interface{}, metadata string) error {
+	s.Plugins.DoRegisterFunction("", fn, metadata)
+	return s.registerFunction(fn, "", false)
+}
+
+// RegisterFunctionName is like RegisterFunction but uses the provided name for the function
+// instead of the function's concrete type.
+func (s *Server) RegisterFunctionName(name string, fn interface{}, metadata string) error {
+	if s.Plugins == nil {
+		s.Plugins = &pluginContainer{}
+	}
+
+	s.Plugins.DoRegisterFunction(name, fn, metadata)
+	return s.registerFunction(fn, name, true)
+}
+
 func (s *Server) register(rcvr interface{}, name string, useName bool) error {
 	s.serviceMapMu.Lock()
 	defer s.serviceMapMu.Unlock()
@@ -119,6 +153,70 @@ func (s *Server) register(rcvr interface{}, name string, useName bool) error {
 	return nil
 }
 
+func (s *Server) registerFunction(fn interface{}, name string, useName bool) error {
+	s.serviceMapMu.Lock()
+	defer s.serviceMapMu.Unlock()
+	if s.serviceMap == nil {
+		s.serviceMap = make(map[string]*service)
+	}
+
+	f, ok := fn.(reflect.Value)
+	if !ok {
+		f = reflect.ValueOf(fn)
+	}
+	if f.Kind() != reflect.Func {
+		return errors.New("function must be func or bound method")
+	}
+
+	fname := reflect.Indirect(f).Type().Name()
+	if useName {
+		fname = name
+	}
+	if fname == "" {
+		errorStr := "rpcx.registerFunction: no func name for type " + f.Type().String()
+		log.Error(errorStr)
+		return errors.New(errorStr)
+	}
+
+	t := f.Type()
+	if t.NumIn() != 3 {
+		return fmt.Errorf("rpcx.registerFunction: has wrong number of ins: %s", f.Type().String())
+	}
+	if t.NumOut() != 1 {
+		return fmt.Errorf("rpcx.registerFunction: has wrong number of outs: %s", f.Type().String())
+	}
+
+	// First arg must be context.Context
+	ctxType := t.In(0)
+	if !ctxType.Implements(typeOfContext) {
+		return fmt.Errorf("function %s must use context as  the first parameter", f.Type().String())
+	}
+
+	argType := t.In(1)
+	if !isExportedOrBuiltinType(argType) {
+		return fmt.Errorf("function %s parameter type not exported: %v", f.Type().String(), argType)
+	}
+
+	replyType := t.In(2)
+	if replyType.Kind() != reflect.Ptr {
+		return fmt.Errorf("function %s reply type not a pointer: %s", f.Type().String(), replyType)
+	}
+	if !isExportedOrBuiltinType(replyType) {
+		return fmt.Errorf("function %s reply type not exported: %v", f.Type().String(), replyType)
+	}
+
+	// The return type of the method must be error.
+	if returnType := t.Out(0); returnType != typeOfError {
+		return fmt.Errorf("function %s returns %s, not error", f.Type().String(), returnType.String())
+	}
+
+	// Install the methods
+	emptyService.function[fname] = &functionType{fn: f, ArgType: argType, ReplyType: replyType}
+
+	s.serviceMap[""] = emptyService
+	return nil
+}
+
 // suitableMethods returns suitable Rpc methods of typ, it will report
 // error using log if reportErr is true.
 func suitableMethods(typ reflect.Type, reportErr bool) map[string]*methodType {
@@ -142,7 +240,7 @@ func suitableMethods(typ reflect.Type, reportErr bool) map[string]*methodType {
 		ctxType := mtype.In(1)
 		if !ctxType.Implements(typeOfContext) {
 			if reportErr {
-				log.Info("method", mname, "has wrong number of ins:", mtype.NumIn())
+				log.Info("method", mname, " must use context.Context as the first parameter")
 			}
 			continue
 		}
@@ -151,7 +249,7 @@ func suitableMethods(typ reflect.Type, reportErr bool) map[string]*methodType {
 		argType := mtype.In(2)
 		if !isExportedOrBuiltinType(argType) {
 			if reportErr {
-				log.Info(mname, "argument type not exported:", argType)
+				log.Info(mname, "parameter type not exported:", argType)
 			}
 			continue
 		}
@@ -207,3 +305,21 @@ func (s *service) call(ctx context.Context, mtype *methodType, argv, replyv refl
 
 	return nil
 }
+
+func (s *service) callForFunction(ctx context.Context, ft *functionType, argv, replyv reflect.Value) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("internal error: %v", r)
+		}
+	}()
+
+	// Invoke the function, providing a new value for the reply.
+	returnValues := ft.fn.Call([]reflect.Value{reflect.ValueOf(ctx), argv, replyv})
+	// The return value for the method is an error.
+	errInter := returnValues[0].Interface()
+	if errInter != nil {
+		return errInter.(error)
+	}
+
+	return nil
+}