package errors import ( "fmt" ) func HasCode(err error, code int) bool { if errWithCode, ok := err.(ErrorWithCode); ok { return errWithCode.Code() == code } return false } type ErrorWithCode interface { error Code() int } type ErrorCode int func (code ErrorCode) Code() int { return int(code) } func (code ErrorCode) Prefix() string { return fmt.Sprintf("[Error 0x%04X] ", code.Code()) } type AuthenticationError struct { ErrorCode AuthDetail interface{} } func NewAuthenticationError(detail interface{}) AuthenticationError { return AuthenticationError{ ErrorCode: 1, AuthDetail: detail, } } func (err AuthenticationError) Error() string { return fmt.Sprintf("%sInvalid auth %v", err.Prefix(), err.AuthDetail) } type ProtocolVersionError struct { ErrorCode Version int } func NewProtocolVersionError(version int) ProtocolVersionError { return ProtocolVersionError{ ErrorCode: 2, Version: version, } } func (err ProtocolVersionError) Error() string { return fmt.Sprintf("%sInvalid version %d", err.Prefix(), err.Version) } type CorruptedPacketError struct { ErrorCode } var corruptedPacketErrorInstance = CorruptedPacketError{ErrorCode: 3} func NewCorruptedPacketError() CorruptedPacketError { return corruptedPacketErrorInstance } func (err CorruptedPacketError) Error() string { return err.Prefix() + "Corrupted packet." } type IPFormatError struct { ErrorCode IP []byte } func NewIPFormatError(ip []byte) IPFormatError { return IPFormatError{ ErrorCode: 4, IP: ip, } } func (err IPFormatError) Error() string { return fmt.Sprintf("%sInvalid IP %v", err.Prefix(), err.IP) } type ConfigurationError struct { ErrorCode } var configurationErrorInstance = ConfigurationError{ErrorCode: 5} func NewConfigurationError() ConfigurationError { return configurationErrorInstance } func (r ConfigurationError) Error() string { return r.Prefix() + "Invalid configuration." } type InvalidOperationError struct { ErrorCode Operation string } func NewInvalidOperationError(operation string) InvalidOperationError { return InvalidOperationError{ ErrorCode: 6, Operation: operation, } } func (r InvalidOperationError) Error() string { return r.Prefix() + "Invalid operation: " + r.Operation }