// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package once

import (
	"context"
	"sync"
	"sync/atomic"
)

// Inspired from Golang sync.Once but it is only marked
// initialized when the provided function returns nil.

// Init represents the structure.
type Init struct {
	done uint32
	m    sync.Mutex
}

// Do is similar to sync.Once.Do - makes one successful

	var config BucketSSEConfig
	err := xml.NewDecoder(r).Decode(&config)
	if err != nil {
		return nil, err
	}

	// Validates server-side encryption config rules
	// Only one rule is allowed on AWS S3
	if len(config.Rules) != 1 {
		return nil, errors.New("only one server-side encryption rule is allowed at a time")
	}

	for _, rule := range config.Rules {
		switch rule.DefaultEncryptionAction.Algorithm {
		case AES256:

	ErrInvalidDataSource: {
		Code:           "InvalidDataSource",
		Description:    "Invalid data source type. Only CSV and JSON are supported at this time.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidExpressionType: {
		Code:           "InvalidExpressionType",
		Description:    "The ExpressionType is invalid. Only SQL expressions are supported at this time.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrBusy: {

	"github.com/minio/mux"
	"github.com/minio/pkg/v2/policy"
)

// Data types used for returning dummy access control
// policy XML, these variables shouldn't be used elsewhere
// they are only defined to be used in this file alone.
type grantee struct {
	XMLNS       string `xml:"xmlns:xsi,attr"`
	XMLXSI      string `xml:"xsi:type,attr"`
	Type        string `xml:"Type"`
	ID          string `xml:"ID,omitempty"`

	flag.StringVar(&minioUsername, "u", "", "MinIO Username")
	flag.StringVar(&minioPassword, "p", "", "MinIO Password")
	flag.BoolVar(&displayCreds, "d", false, "Only show generated credentials")
	flag.DurationVar(&expiryDuration, "e", 0, "Request a duration of validity for the generated credential")
	flag.StringVar(&bucketToList, "b", "", "Bucket to list (defaults to username)")

}

// Verify if the request has AWS Streaming Signature Version '4'. This is only valid for 'PUT' operation.
func isRequestSignStreamingV4(r *http.Request) bool {
	return r.Header.Get(xhttp.AmzContentSha256) == streamingContentSHA256 &&
		r.Method == http.MethodPut
}

// Verify if the request has AWS Streaming Signature Version '4'. This is only valid for 'PUT' operation.
func isRequestSignStreamingTrailerV4(r *http.Request) bool {

	case emptySHA256:
		// some broken clients set empty-sha256
		// with > 0 content-length in the body,
		// we should skip such clients and allow
		// blindly such insecure clients only if
		// S3 strict compatibility is disabled.

		// We return true only in situations when
		// deployment has asked MinIO to allow for
		// such broken clients and content-length > 0.
		return r.ContentLength > 0 && !globalServerCtxt.StrictS3Compat
	}

		WriteMerges:  stats[5],
		WriteSectors: stats[6],
		WriteTicks:   stats[7],
		CurrentIOs:   stats[8],
		TotalTicks:   stats[9],
		ReqTicks:     stats[10],
	}
	// as per the doc, only 11 fields are guaranteed
	// only set if available
	if len(stats) > 14 {
		iostats.DiscardIOs = stats[11]
		iostats.DiscardMerges = stats[12]
		iostats.DiscardSectors = stats[13]
		iostats.DiscardTicks = stats[14]
	}
	return

	// handles service freeze or un-freeze S3 API calls.
	globalServiceFreeze atomic.Value

	// Only needed for tracking
	globalServiceFreezeCnt int32
	globalServiceFreezeMu  sync.Mutex // Updates.

	// List of local drives to this node, this is only set during server startup,
	// and is only mutated by HealFormat. Hold globalLocalDrivesMu to access.
	globalLocalDrives   []StorageAPI
	globalLocalDrivesMu sync.RWMutex

	// request into an SSE-S3 request.
	// If present EnvAutoEncryption must be either "on" or "off".
	EnvKMSAutoEncryption = "MINIO_KMS_AUTO_ENCRYPTION"
)

// LookupAutoEncryption returns true if and only if
// the MINIO_KMS_AUTO_ENCRYPTION env. variable is
// set to "on".
func LookupAutoEncryption() bool {
	auto, _ := config.ParseBool(env.Get(EnvKMSAutoEncryption, config.EnableOff))
	return auto