}

// writeErrorResponse writes error headers
func writeErrorResponse(ctx context.Context, w http.ResponseWriter, err APIError, reqURL *url.URL) {
	if err.HTTPStatusCode == http.StatusServiceUnavailable {
		// Set retry-after header to indicate user-agents to retry request after 120secs.
		// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After
		w.Header().Set(xhttp.RetryAfter, "120")
	}

	switch err.Code {

}()

// Set of handler options as bit flags
type hFlag uint8

const (
	// this flag disables gzip compression of responses
	noGZFlag = 1 << iota

	// this flag enables tracing body and headers instead of just headers
	traceAllFlag

	// pass this flag to skip checking if object layer is available
	noObjLayerFlag
)

// Has checks if the given flag is enabled in `h`.
func (h hFlag) Has(flag hFlag) bool {

)

// writeSTSErrorResponse writes error headers
func writeSTSErrorResponse(ctx context.Context, w http.ResponseWriter, errCode STSErrorCode, err error) {
	stsErr := stsErrCodes.ToSTSErr(errCode)

	// Generate error response.
	stsErrorResponse := STSErrorResponse{}
	stsErrorResponse.Error.Code = stsErr.Code
	stsErrorResponse.RequestID = w.Header().Get(xhttp.AmzRequestID)

	UserTags string

	// List of individual parts, maximum size of upto 10,000
	Parts []ObjectPartInfo `json:"-"`

	// Implements writer and reader used by CopyObject API
	Writer       io.WriteCloser `json:"-" msg:"-"`
	Reader       *hash.Reader   `json:"-" msg:"-"`
	PutObjReader *PutObjReader  `json:"-" msg:"-"`

	metadataOnly bool
	versionOnly  bool // adds a new version, only used by CopyObject

// functionality to handle SSE-C copy requests.
var SSECopy = ssecCopy{}

type ssecCopy struct{}

// IsRequested returns true if the HTTP headers contains
// at least one SSE-C copy header. Regular SSE-C headers
// are ignored.
func (ssecCopy) IsRequested(h http.Header) bool {
	if _, ok := h[xhttp.AmzServerSideEncryptionCopyCustomerAlgorithm]; ok {
		return true
	}

}

// readGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers.
// If they are found, then this function reads the sparse map and returns it.
// This assumes that 0.0 headers have already been converted to 0.1 headers
// by the PAX header parsing logic.
func (tr *Reader) readGNUSparsePAXHeaders(hdr *Header) (sparseDatas, error) {
	// Identify the version of GNU headers.
	var is1x0 bool

			withJSON: `{"request":{"uri":"/1","header":{"User-Agent":"test"}}}
{"request":{"uri":"/2","header":{}}}`,
		},
		{
			name:  "is-not-missing-2",
			query: `select * from s3object[*] as s where s.request.header is not missing`,
			wantResult: `{"request":{"uri":"/1","header":{"User-Agent":"test"}}}
{"request":{"uri":"/2","header":{}}}`,
			withJSON: `{"request":{"uri":"/1","header":{"User-Agent":"test"}}}

	tr.ResponseHeaderTimeout = 30 * time.Minute

	return func() *http.Transport {
		return tr
	}
}

// NewHTTPTransportWithTimeout allows setting a timeout for response headers
func (s ConnSettings) NewHTTPTransportWithTimeout(timeout time.Duration) *http.Transport {
	tr := s.getDefaultTransport(0)

	// Settings specific to this transport.
	tr.ResponseHeaderTimeout = timeout
	return tr

	}, ErrNone
}

// Represents the overall state that is required for decoding a
// AWS Signature V4 chunked reader.
type s3ChunkedReader struct {
	reader        *bufio.Reader
	cred          auth.Credentials
	seedSignature string
	seedDate      time.Time
	region        string
	trailers      http.Header

	chunkSHA256Writer hash.Hash // Calculates sha256 of chunk data.
	buffer            []byte
	offset            int

func isCompressible(header http.Header, object string) bool {
	globalCompressConfigMu.Lock()
	cfg := globalCompressConfig
	globalCompressConfigMu.Unlock()

	return !excludeForCompression(header, object, cfg)
}

// Eliminate the non-compressible objects.
func excludeForCompression(header http.Header, object string, cfg compress.Config) bool {
	objStr := object