umarshal - refactor skip from recursive calls to a loop. (#636)

plugin/unmarshal/unmarshal.go

@@ -1578,6 +1578,7 @@ func (p *unmarshal) Generate(file *generator.FileDescriptor) {
 	p.P(`func skip` + p.localName + `(dAtA []byte) (n int, err error) {
 		l := len(dAtA)
 		iNdEx := 0
+		depth := 0
 		for iNdEx < l {
 			var wire uint64
 			for shift := uint(0); ; shift += 7 {
@@ -1609,10 +1610,8 @@ func (p *unmarshal) Generate(file *generator.FileDescriptor) {
 						break
 					}
 				}
-				return iNdEx, nil
 			case 1:
 				iNdEx += 8
-				return iNdEx, nil
 			case 2:
 				var length int
 				for shift := uint(0); ; shift += 7 {
@@ -1633,57 +1632,32 @@ func (p *unmarshal) Generate(file *generator.FileDescriptor) {
 					return 0, ErrInvalidLength` + p.localName + `
 				}
 				iNdEx += length
-				if iNdEx < 0 {
-					return 0, ErrInvalidLength` + p.localName + `
-				}
-				return iNdEx, nil
 			case 3:
-				for {
-					var innerWire uint64
-					var start int = iNdEx
-					for shift := uint(0); ; shift += 7 {
-						if shift >= 64 {
-							return 0, ErrIntOverflow` + p.localName + `
-						}
-						if iNdEx >= l {
-							return 0, ` + p.ioPkg.Use() + `.ErrUnexpectedEOF
-						}
-						b := dAtA[iNdEx]
-						iNdEx++
-						innerWire |= (uint64(b) & 0x7F) << shift
-						if b < 0x80 {
-							break
-						}
-					}
-					innerWireType := int(innerWire & 0x7)
-					if innerWireType == 4 {
-						break
-					}
-					next, err := skip` + p.localName + `(dAtA[start:])
-					if err != nil {
-						return 0, err
-					}
-					iNdEx = start + next
-					if iNdEx < 0 {
-						return 0, ErrInvalidLength` + p.localName + `
-					}
-				}
-				return iNdEx, nil
+				depth++
 			case 4:
-				return iNdEx, nil
+				if depth == 0 {
+					return 0, ErrUnexpectedEndOfGroup` + p.localName + `
+				}
+				depth--
 			case 5:
 				iNdEx += 4
-				return iNdEx, nil
 			default:
 				return 0, ` + fmtPkg.Use() + `.Errorf("proto: illegal wireType %d", wireType)
 			}
+			if iNdEx < 0 {
+				return 0, ErrInvalidLength` + p.localName + `
+			}
+			if depth == 0 {
+				return iNdEx, nil
+			}
 		}
-		panic("unreachable")
+		return 0, ` + p.ioPkg.Use() + `.ErrUnexpectedEOF
 	}
 
 	var (
 		ErrInvalidLength` + p.localName + ` = ` + fmtPkg.Use() + `.Errorf("proto: negative length found during unmarshaling")
 		ErrIntOverflow` + p.localName + ` = ` + fmtPkg.Use() + `.Errorf("proto: integer overflow")
+		ErrUnexpectedEndOfGroup` + p.localName + ` = ` + fmtPkg.Use() + `.Errorf("proto: unexpected end of group")
 	)
 	`)
 }