preloader.go (1949B)
1 /* 2 * 3 * Copyright 2019 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 package grpc 20 21 import ( 22 "google.golang.org/grpc/codes" 23 "google.golang.org/grpc/status" 24 ) 25 26 // PreparedMsg is responsible for creating a Marshalled and Compressed object. 27 // 28 // # Experimental 29 // 30 // Notice: This type is EXPERIMENTAL and may be changed or removed in a 31 // later release. 32 type PreparedMsg struct { 33 // Struct for preparing msg before sending them 34 encodedData []byte 35 hdr []byte 36 payload []byte 37 } 38 39 // Encode marshalls and compresses the message using the codec and compressor for the stream. 40 func (p *PreparedMsg) Encode(s Stream, msg interface{}) error { 41 ctx := s.Context() 42 rpcInfo, ok := rpcInfoFromContext(ctx) 43 if !ok { 44 return status.Errorf(codes.Internal, "grpc: unable to get rpcInfo") 45 } 46 47 // check if the context has the relevant information to prepareMsg 48 if rpcInfo.preloaderInfo == nil { 49 return status.Errorf(codes.Internal, "grpc: rpcInfo.preloaderInfo is nil") 50 } 51 if rpcInfo.preloaderInfo.codec == nil { 52 return status.Errorf(codes.Internal, "grpc: rpcInfo.preloaderInfo.codec is nil") 53 } 54 55 // prepare the msg 56 data, err := encode(rpcInfo.preloaderInfo.codec, msg) 57 if err != nil { 58 return err 59 } 60 p.encodedData = data 61 compData, err := compress(data, rpcInfo.preloaderInfo.cp, rpcInfo.preloaderInfo.comp) 62 if err != nil { 63 return err 64 } 65 p.hdr, p.payload = msgHeader(data, compData) 66 return nil 67 }