res := aoBucketInfo.New()
	for i := range buckets {
		bucket := buckets[i]
		res.Append(&bucket)
	}
	return res, nil
}

// HeadBucketHandler implements peer BucketInfo call, returns bucket create date.
func (s *peerRESTServer) HeadBucketHandler(mss *grid.MSS) (info *VolInfo, nerr *grid.RemoteErr) {
	bucket := mss.Get(peerS3Bucket)
	if isMinioMetaBucket(bucket) {
		return info, grid.NewRemoteErr(errInvalidArgument)

	// Compare only necessary headers
	compareKeys := []string{
		"Expires",
		"Cache-Control",
		"Content-Language",
		"Content-Disposition",
		"X-Amz-Object-Lock-Mode",
		"X-Amz-Object-Lock-Retain-Until-Date",
		"X-Amz-Object-Lock-Legal-Hold",
		"X-Amz-Website-Redirect-Location",
		"X-Amz-Meta-",
	}

	// compare metadata on both maps to see if meta is identical
	compareMeta1 := make(map[string]string)

		s string
		t time.Time
	}{
		{"2010T", time.Date(2010, 1, 1, 0, 0, 0, 0, time.UTC)},
		{"2010-02T", time.Date(2010, 2, 1, 0, 0, 0, 0, time.UTC)},
		{"2010-02-03T", time.Date(2010, 2, 3, 0, 0, 0, 0, time.UTC)},
		{"2010-02-03T04:11Z", time.Date(2010, 2, 3, 4, 11, 0, 0, time.UTC)},
		{"2010-02-03T04:11:30Z", time.Date(2010, 2, 3, 4, 11, 30, 0, time.UTC)},
		{"2010-02-03T04:11:30.23Z", time.Date(2010, 2, 3, 4, 11, 30, 230000000, time.UTC)},

		canonicalHeaders += "\n"
	}

	date := expires // Date is set to expires date for presign operations.
	if date == "" {
		// If expires date is empty then request header Date is used.
		date = headers.Get(xhttp.Date)
	}

	// From the Amazon docs:
	//
	// StringToSign = HTTP-Verb + "\n" +
	// 	 Content-Md5 + "\n" +
	//	 Content-Type + "\n" +
	//	 Date/Expires + "\n" +
	//	 CanonicalizedProtocolHeaders +

type preSignValues struct {
	signValues
	Date    time.Time
	Expires time.Duration
}

// Parses signature version '4' query string of the following form.
//
//	querystring = X-Amz-Algorithm=algorithm
//	querystring += &X-Amz-Credential= urlencode(accessKey + '/' + credential_scope)
//	querystring += &X-Amz-Date=date
//	querystring += &X-Amz-Expires=timeout interval

	// Add the algorithm condition, only accept AWS SignV4 Sha256.
	algorithmConditionStr := `["eq", "$x-amz-algorithm", "AWS4-HMAC-SHA256"]`
	// Add the date condition, only accept the current date.
	dateConditionStr := fmt.Sprintf(`["eq", "$x-amz-date", "%s"]`, t.Format(iso8601DateFormat))
	// Add the credential string, only accept the credential passed.

// Objects under site wide WORM can never be overwritten.
// For objects in "Governance" mode, overwrite is allowed if a) object retention date is past OR
// governance bypass headers are set and user has governance bypass permissions.
// Objects in "Compliance" mode can be overwritten only if retention date is past.

	region = signV4Values.Credential.scope.region

	// Extract date, if not present throw error.
	var dateStr string
	if dateStr = req.Header.Get("x-amz-date"); dateStr == "" {
		if dateStr = r.Header.Get("Date"); dateStr == "" {
			return cred, "", "", time.Time{}, ErrMissingDateHeader
		}
	}

	// Parse date header.
	var err error
	date, err = time.Parse(iso8601Format, dateStr)
	if err != nil {

		expectedErr    error
	}{
		{
			// valid: represents a restored object, 'pending' expiry.
			restoreHdr: `ongoing-request="false", expiry-date="Fri, 21 Dec 2012 00:00:00 GMT"`,
			expectedStatus: restoreObjStatus{
				ongoing: false,
				expiry:  time.Date(2012, 12, 21, 0, 0, 0, 0, time.UTC),
			},
			expectedErr: nil,
		},
		{
			// valid: represents an ongoing restore object request.

		{
			name:       "date_diff_year",
			query:      `SELECT date_diff(year, '2010-01-01T', '2011-01-01T') FROM S3Object LIMIT 1`,
			wantResult: `{"_1":1}`,
		},
		{
			name:       "date_diff_year",
			query:      `SELECT date_diff(month, '2010-01-01T', '2010-05T') FROM S3Object LIMIT 1`,