public static final String CONSTRAINTS_CreditCardNumber_MESSAGE = "{constraints.CreditCardNumber.message}";

    /** The key of the message: {item} is invalid {type} barcode. */
    public static final String CONSTRAINTS_EAN_MESSAGE = "{constraints.EAN.message}";

    /** The key of the message: {item} is not a well-formed email address. */

	// calling the function being tested.
	errCode := checkMetaHeaders(signedHeadersMap, r)
	if errCode != ErrNone {
		t.Fatalf("Expected the APIErrorCode to be %d, but got %d", ErrNone, errCode)
	}

	// Add new metadata in inputHeader
	inputHeader.Set("X-Amz-Meta-Clone", "fail")
	// calling the function being tested.
	errCode = checkMetaHeaders(signedHeadersMap, r)
	if errCode != ErrUnsignedHeaders {

	testCases := []struct {
		Request *http.Request
		ErrCode APIErrorCode
	}{
		{Request: mustNewRequest(http.MethodGet, "http://127.0.0.1:9000", 0, nil, t), ErrCode: ErrAccessDenied},
		{Request: mustNewSignedRequest(http.MethodGet, "http://127.0.0.1:9000", 0, nil, t), ErrCode: ErrNone},
		{Request: mustNewSignedV2Request(http.MethodGet, "http://127.0.0.1:9000", 0, nil, t), ErrCode: ErrAccessDenied},

	"github.com/minio/minio/internal/logger"
)

// 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)

	// Extract all the listBucketVersions query params to their native values.
	prefix, marker, delimiter, maxkeys, encodingType, versionIDMarker, errCode := getListBucketObjectVersionsArgs(urlValues)
	if errCode != ErrNone {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(errCode), r.URL)
		return
	}

	// Validate the query params before beginning to serve the request.

	if s3Err != ErrNone {
		return s3Err
	}

	// Extract all the signed headers along with its values.
	extractedSignedHeaders, errCode := extractSignedHeaders(pSignValues.SignedHeaders, r)
	if errCode != ErrNone {
		return errCode
	}

	// Check if the metadata headers are equal with signedheaders
	errMetaCode := checkMetaHeaders(extractedSignedHeaders, r)
	if errMetaCode != ErrNone {

// Verify if request has valid AWS Signature Version '4'.
func isReqAuthenticated(ctx context.Context, r *http.Request, region string, stype serviceType) (s3Error APIErrorCode) {
	if errCode := reqSignatureV4Verify(r, region, stype); errCode != ErrNone {
		return errCode
	}

	clientETag, err := etag.FromContentMD5(r.Header)
	if err != nil {
		return ErrInvalidDigest
	}

				if toAPIError(ctx, err).Code == "NoSuchKey" {
					s3Error = ErrNoSuchKey
				}
			}
		}
		errCode := errorCodes.ToAPIErr(s3Error)
		w.Header().Set(xMinIOErrCodeHeader, errCode.Code)
		w.Header().Set(xMinIOErrDescHeader, "\""+errCode.Description+"\"")
		writeErrorResponseHeadersOnly(w, errCode)
		return
	}

	// Validate pre-conditions if any.
	opts.CheckPrecondFn = func(oi ObjectInfo) bool {

    return patternCompiler.isPcreLike();
  }

  private static PatternCompiler loadPatternCompiler() {
    /*
     * We'd normally use ServiceLoader here, but it hurts Android startup performance. To avoid
     * that, we hardcode the JDK Pattern compiler on Android (and, inadvertently, on App Engine and
     * in Guava, at least for now).
     */
    return new JdkPatternCompiler();
  }

        DnsResolver.FLAG_EMPTY,
        executor,
        null,
        object : DnsResolver.Callback<List<InetAddress>> {
          override fun onAnswer(
            addresses: List<InetAddress>,
            rCode: Int,
          ) {
            callback.onResponse(hostname, addresses)
          }

          override fun onError(e: DnsResolver.DnsException) {
            callback.onFailure(
              hostname,