diff options
Diffstat (limited to 'libgo/go/net/rpc/server.go')
| -rw-r--r-- | libgo/go/net/rpc/server.go | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/libgo/go/net/rpc/server.go b/libgo/go/net/rpc/server.go index 920ae9137a6..1680e2f0d70 100644 --- a/libgo/go/net/rpc/server.go +++ b/libgo/go/net/rpc/server.go @@ -13,13 +13,19 @@ Only methods that satisfy these criteria will be made available for remote access; other methods will be ignored: - - the method name is exported, that is, begins with an upper case letter. - - the method receiver is exported or local (defined in the package - registering the service). - - the method has two arguments, both exported or local types. + - the method is exported. + - the method has two arguments, both exported (or builtin) types. - the method's second argument is a pointer. - the method has return type error. + In effect, the method must look schematically like + + func (t *T) MethodName(argType T1, replyType *T2) error + + where T, T1 and T2 can be marshaled by encoding/gob. + These requirements apply even if a different codec is used. + (In future, these requirements may soften for custom codecs.) + The method's first argument represents the arguments provided by the caller; the second argument represents the result parameters to be returned to the caller. The method's return value, if non-nil, is passed back as a string that the client @@ -36,10 +42,12 @@ call, a pointer containing the arguments, and a pointer to receive the result parameters. - Call waits for the remote call to complete; Go launches the call asynchronously - and returns a channel that will signal completion. + The Call method waits for the remote call to complete while the Go method + launches the call asynchronously and signals completion using the Call + structure's Done channel. - Package "gob" is used to transport the data. + Unless an explicit codec is set up, package encoding/gob is used to + transport the data. Here is a simple example. A server wishes to export an object of type Arith: @@ -256,6 +264,7 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro method := s.typ.Method(m) mtype := method.Type mname := method.Name + // Method must be exported. if method.PkgPath != "" { continue } @@ -267,7 +276,7 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro // First arg need not be a pointer. argType := mtype.In(1) if !isExportedOrBuiltinType(argType) { - log.Println(mname, "argument type not exported or local:", argType) + log.Println(mname, "argument type not exported:", argType) continue } // Second arg must be a pointer. @@ -276,15 +285,17 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro log.Println("method", mname, "reply type not a pointer:", replyType) continue } + // Reply type must be exported. if !isExportedOrBuiltinType(replyType) { - log.Println("method", mname, "reply type not exported or local:", replyType) + log.Println("method", mname, "reply type not exported:", replyType) continue } - // Method needs one out: error. + // Method needs one out. if mtype.NumOut() != 1 { log.Println("method", mname, "has wrong number of outs:", mtype.NumOut()) continue } + // The return type of the method must be error. if returnType := mtype.Out(0); returnType != typeOfError { log.Println("method", mname, "returns", returnType.String(), "not error") continue @@ -301,10 +312,10 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro return nil } -// A value sent as a placeholder for the response when the server receives an invalid request. -type InvalidRequest struct{} - -var invalidRequest = InvalidRequest{} +// A value sent as a placeholder for the server's response value when the server +// receives an invalid request. It is never decoded by the client since the Response +// contains an error when it is used. +var invalidRequest = struct{}{} func (server *Server) sendResponse(sending *sync.Mutex, req *Request, reply interface{}, codec ServerCodec, errmsg string) { resp := server.getResponse() |