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
// call to the function. ie, it invokes the function

	}

	// If batch is enabled, the event will be batched in memory
	// and will be committed once the batch is full.
	if target.batch != nil {
		return target.addToBatch(key)
	}

	eventData, eErr := target.store.Get(key.Name)
	if eErr != nil {
		// The last event key in a successful batch will be sent in the channel atmost once by the replayEvents()
		// Such events will not exist and wouldve been already been sent successfully.

	p.health.waiting.Add(1)

	ctx = context.WithValue(ctx, healthDiskCtxKey{}, &healthDiskCtxValue{lastSuccess: &p.health.lastSuccess})
	si := p.updateStorageMetrics(s, paths...)
	var once sync.Once
	return ctx, func(errp *error) {
		p.health.waiting.Add(-1)
		once.Do(func() {
			if errp != nil {
				err := *errp
				if err == nil || errors.Is(err, io.EOF) {
					p.health.logSuccess()
				}
			}
			si(errp)
		})

	"path/filepath"
	"strings"
	"syscall"
	"time"

	"github.com/minio/minio/internal/event"
	xhttp "github.com/minio/minio/internal/http"
	"github.com/minio/minio/internal/logger"
	"github.com/minio/minio/internal/once"
	"github.com/minio/minio/internal/store"
	"github.com/minio/pkg/v2/certs"
	xnet "github.com/minio/pkg/v2/net"
)

// Webhook constants
const (
	WebhookEndpoint   = "endpoint"
	WebhookAuthToken  = "auth_token"

	"errors"
	"fmt"
	"net/url"
	"os"
	"path/filepath"

	"github.com/google/uuid"
	"github.com/minio/minio/internal/event"
	"github.com/minio/minio/internal/logger"
	"github.com/minio/minio/internal/once"
	"github.com/minio/minio/internal/store"
	xnet "github.com/minio/pkg/v2/net"
	"github.com/nats-io/nats.go"
	"github.com/nats-io/stan.go"
)

// NATS related constants
const (
	NATSAddress       = "address"

	CreateKey(ctx context.Context, keyID string) error

	// DeleteKey deletes a key at the KMS with the given key ID.
	// Please note that is a dangerous operation.
	// Once a key has been deleted all data that has been encrypted with it cannot be decrypted
	// anymore, and therefore, is lost.
	DeleteKey(ctx context.Context, keyID string) error

	// ListKeys lists all key names.

	// If an error is returned the cached value is not set.
	// Only one caller will call this function at any time, others will be blocking.
	// The returned value can no longer be modified once returned.
	// Should be set before calling Get().
	updateFn func() (T, error)

	// ttl for a cached value.
	ttl time.Duration

	opts Opts

	// Once can be used to initialize values for lazy initialization.

	"sync"
)

// PipeWriter is similar to io.PipeWriter with wait group
type PipeWriter struct {
	*io.PipeWriter
	once sync.Once
	done func()
}

// CloseWithError close with supplied error the writer end.
func (w *PipeWriter) CloseWithError(err error) error {
	err = w.PipeWriter.CloseWithError(err)
	w.once.Do(func() {
		w.done()
	})
	return err
}

// PipeReader is similar to io.PipeReader with wait group

		objects = objects[:maxKeys]
		loi.IsTruncated = true
	}
	for _, obj := range objects {
		if obj.IsDir && obj.ModTime.IsZero() && delimiter != "" {
			// Only add each once.
			// With slash delimiter we only get the directory once.
			found := false
			if delimiter != slashSeparator {
				for _, p := range loi.Prefixes {
					if found {
						break
					}
					found = p == obj.Name
				}

	doneCh := make(chan error, 1)
	defer xioutil.SafeClose(doneCh)

	// Save rebalance.bin periodically.
	go func() {
		// Update rebalance.bin periodically once every 5-10s, chosen randomly
		// to avoid multiple pool leaders herding to update around the same
		// time.
		r := rand.New(rand.NewSource(time.Now().UnixNano()))
		randSleepFor := func() time.Duration {