modernizes for loop in cmd/, internal/ (#21309)

cmd/api-utils.go

@@ -43,7 +43,7 @@ func shouldEscape(c byte) bool {
 //   - Force encoding of '~'
 func s3URLEncode(s string) string {
 	spaceCount, hexCount := 0, 0
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		c := s[i]
 		if shouldEscape(c) {
 			if c == ' ' {
@@ -70,7 +70,7 @@ func s3URLEncode(s string) string {
 
 	if hexCount == 0 {
 		copy(t, s)
-		for i := 0; i < len(s); i++ {
+		for i := range len(s) {
 			if s[i] == ' ' {
 				t[i] = '+'
 			}
@@ -79,7 +79,7 @@ func s3URLEncode(s string) string {
 	}
 
 	j := 0
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		switch c := s[i]; {
 		case c == ' ':
 			t[j] = '+'

cmd/background-heal-ops.go

@@ -102,7 +102,7 @@ func waitForLowHTTPReq() {
 func initBackgroundHealing(ctx context.Context, objAPI ObjectLayer) {
 	bgSeq := newBgHealSequence()
 	// Run the background healer
-	for i := 0; i < globalBackgroundHealRoutine.workers; i++ {
+	for range globalBackgroundHealRoutine.workers {
 		go globalBackgroundHealRoutine.AddWorker(ctx, objAPI, bgSeq)
 	}
 

cmd/batch-handlers.go

@@ -248,7 +248,7 @@ func (r *BatchJobReplicateV1) copyWithMultipartfromSource(ctx context.Context, a
 		pInfo PartInfo
 	)
 
-	for i := 0; i < partsCount; i++ {
+	for i := range partsCount {
 		gopts := minio.GetObjectOptions{
 			VersionID:  srcObjInfo.VersionID,
 			PartNumber: i + 1,

cmd/consolelogger.go

@@ -113,7 +113,7 @@ func (sys *HTTPConsoleLoggerSys) Subscribe(subCh chan log.Info, doneCh <-chan st
 	sys.RUnlock()
 	// send last n console log messages in order filtered by node
 	if cnt > 0 {
-		for i := 0; i < last; i++ {
+		for i := range last {
 			entry := lastN[(cnt+i)%last]
 			if (entry == log.Info{}) {
 				continue

cmd/erasure-multipart.go

@@ -1481,7 +1481,7 @@ func (er erasureObjects) CompleteMultipartUpload(ctx context.Context, bucket str
 		}
 	}
 
-	for i := 0; i < len(onlineDisks); i++ {
+	for i := range len(onlineDisks) {
 		if onlineDisks[i] != nil && onlineDisks[i].IsOnline() {
 			// Object info is the same in all disks, so we can pick
 			// the first meta from online disk

cmd/erasure-object.go

@@ -504,7 +504,7 @@ func (er erasureObjects) deleteIfDangling(ctx context.Context, bucket, object st
 
 	// count the number of offline disks
 	offline := 0
-	for i := 0; i < len(errs); i++ {
+	for i := range len(errs) {
 		var found bool
 		switch {
 		case errors.Is(errs[i], errDiskNotFound):
@@ -1221,7 +1221,7 @@ func (er erasureObjects) putMetacacheObject(ctx context.Context, key string, r *
 		partsMetadata[index].SetInlineData()
 	}
 
-	for i := 0; i < len(onlineDisks); i++ {
+	for i := range len(onlineDisks) {
 		if onlineDisks[i] != nil && onlineDisks[i].IsOnline() {
 			// Object info is the same in all disks, so we can pick
 			// the first meta from online disk
@@ -1557,7 +1557,7 @@ func (er erasureObjects) putObject(ctx context.Context, bucket string, object st
 		return ObjectInfo{}, toObjectErr(err, bucket, object)
 	}
 
-	for i := 0; i < len(onlineDisks); i++ {
+	for i := range len(onlineDisks) {
 		if onlineDisks[i] != nil && onlineDisks[i].IsOnline() {
 			// Object info is the same in all disks, so we can pick
 			// the first meta from online disk
@@ -1574,7 +1574,7 @@ func (er erasureObjects) putObject(ctx context.Context, bucket string, object st
 		if len(versions) == 0 {
 			// Whether a disk was initially or becomes offline
 			// during this upload, send it to the MRF list.
-			for i := 0; i < len(onlineDisks); i++ {
+			for i := range len(onlineDisks) {
 				if onlineDisks[i] != nil && onlineDisks[i].IsOnline() {
 					continue
 				}

cmd/erasure-server-pool-rebalance.go

@@ -149,7 +149,7 @@ func (z *erasureServerPools) findIndex(index int) int {
 	if z.rebalMeta == nil {
 		return 0
 	}
-	for i := 0; i < len(z.rebalMeta.PoolStats); i++ {
+	for i := range len(z.rebalMeta.PoolStats) {
 		if i == index {
 			return index
 		}

cmd/erasure-sets.go

@@ -95,7 +95,7 @@ func (s *erasureSets) getDiskMap() map[Endpoint]StorageAPI {
 	s.erasureDisksMu.RLock()
 	defer s.erasureDisksMu.RUnlock()
 
-	for i := 0; i < s.setCount; i++ {
+	for i := range s.setCount {
 		for j := 0; j < s.setDriveCount; j++ {
 			disk := s.erasureDisks[i][j]
 			if disk == OfflineDisk {
@@ -150,7 +150,7 @@ func findDiskIndexByDiskID(refFormat *formatErasureV3, diskID string) (int, int,
 	if diskID == offlineDiskUUID {
 		return -1, -1, fmt.Errorf("DriveID: %s is offline", diskID)
 	}
-	for i := 0; i < len(refFormat.Erasure.Sets); i++ {
+	for i := range len(refFormat.Erasure.Sets) {
 		for j := 0; j < len(refFormat.Erasure.Sets[0]); j++ {
 			if refFormat.Erasure.Sets[i][j] == diskID {
 				return i, j, nil
@@ -174,7 +174,7 @@ func findDiskIndex(refFormat, format *formatErasureV3) (int, int, error) {
 		return -1, -1, fmt.Errorf("DriveID: %s is offline", format.Erasure.This)
 	}
 
-	for i := 0; i < len(refFormat.Erasure.Sets); i++ {
+	for i := range len(refFormat.Erasure.Sets) {
 		for j := 0; j < len(refFormat.Erasure.Sets[0]); j++ {
 			if refFormat.Erasure.Sets[i][j] == format.Erasure.This {
 				return i, j, nil
@@ -377,7 +377,7 @@ func newErasureSets(ctx context.Context, endpoints PoolEndpoints, storageDisks [
 
 	mutex := newNSLock(globalIsDistErasure)
 
-	for i := 0; i < setCount; i++ {
+	for i := range setCount {
 		s.erasureDisks[i] = make([]StorageAPI, setDriveCount)
 	}
 
@@ -390,7 +390,7 @@ func newErasureSets(ctx context.Context, endpoints PoolEndpoints, storageDisks [
 
 	var wg sync.WaitGroup
 	var lk sync.Mutex
-	for i := 0; i < setCount; i++ {
+	for i := range setCount {
 		lockerEpSet := set.NewStringSet()
 		for j := 0; j < setDriveCount; j++ {
 			wg.Add(1)
@@ -409,7 +409,7 @@ func newErasureSets(ctx context.Context, endpoints PoolEndpoints, storageDisks [
 	}
 	wg.Wait()
 
-	for i := 0; i < setCount; i++ {
+	for i := range setCount {
 		wg.Add(1)
 		go func(i int) {
 			defer wg.Done()

cmd/fmt-gen.go

@@ -98,7 +98,7 @@ func fmtGenMain(ctxt *cli.Context) {
 		setCount, setDriveCount := pool.SetCount, pool.DrivesPerSet
 		format := newFormatErasureV3(setCount, setDriveCount)
 		format.ID = deploymentID
-		for i := 0; i < setCount; i++ { // for each erasure set
+		for i := range setCount { // for each erasure set
 			for j := 0; j < setDriveCount; j++ {
 				newFormat := format.Clone()
 				newFormat.Erasure.This = format.Erasure.Sets[i][j]

cmd/format-erasure.go

@@ -157,7 +157,7 @@ func newFormatErasureV3(numSets int, setLen int) *formatErasureV3 {
 	format.Erasure.DistributionAlgo = formatErasureVersionV3DistributionAlgoV3
 	format.Erasure.Sets = make([][]string, numSets)
 
-	for i := 0; i < numSets; i++ {
+	for i := range numSets {
 		format.Erasure.Sets[i] = make([]string, setLen)
 		for j := 0; j < setLen; j++ {
 			format.Erasure.Sets[i][j] = mustGetUUID()
@@ -514,7 +514,7 @@ func formatErasureV3Check(reference *formatErasureV3, format *formatErasureV3) e
 	}
 
 	// Make sure that the diskID is found in the set.
-	for i := 0; i < len(tmpFormat.Erasure.Sets); i++ {
+	for i := range len(tmpFormat.Erasure.Sets) {
 		for j := 0; j < len(tmpFormat.Erasure.Sets[i]); j++ {
 			if this == tmpFormat.Erasure.Sets[i][j] {
 				return nil
@@ -639,7 +639,7 @@ func initFormatErasure(ctx context.Context, storageDisks []StorageAPI, setCount,
 		return nil, err
 	}
 
-	for i := 0; i < setCount; i++ {
+	for i := range setCount {
 		hostCount := make(map[string]int, setDriveCount)
 		for j := 0; j < setDriveCount; j++ {
 			disk := storageDisks[i*setDriveCount+j]

cmd/mrf.go

@@ -266,7 +266,7 @@ func (m *mrfState) healRoutine(z *erasureServerPools) {
 				if len(u.Versions) > 0 {
 					vers := len(u.Versions) / 16
 					if vers > 0 {
-						for i := 0; i < vers; i++ {
+						for i := range vers {
 							healObject(u.Bucket, u.Object, uuid.UUID(u.Versions[16*i:]).String(), scan)
 						}
 					}

cmd/notification.go

@@ -123,7 +123,7 @@ func (g *NotificationGroup) Go(ctx context.Context, f func() error, index int, a
 		}
 
 		retryCount := g.retryCount
-		for i := 0; i < retryCount; i++ {
+		for i := range retryCount {
 			g.errs[index].Err = nil
 			if err := f(); err != nil {
 				g.errs[index].Err = err

cmd/object-api-utils.go

@@ -128,7 +128,7 @@ func IsValidBucketName(bucket string) bool {
 		// 'label' in AWS terminology and if the bucket looks
 		// like an IP address.
 		isNotNumber := false
-		for i := 0; i < len(piece); i++ {
+		for i := range len(piece) {
 			switch {
 			case (piece[i] >= 'a' && piece[i] <= 'z' ||
 				piece[i] == '-'):
@@ -254,11 +254,11 @@ func concat(ss ...string) string {
 	}
 	// create & allocate the memory in advance.
 	n := 0
-	for i := 0; i < length; i++ {
+	for i := range length {
 		n += len(ss[i])
 	}
 	b := make([]byte, 0, n)
-	for i := 0; i < length; i++ {
+	for i := range length {
 		b = append(b, ss[i]...)
 	}
 	return unsafe.String(unsafe.SliceData(b), n)

cmd/os-readdir_test.go

@@ -77,7 +77,7 @@ func setupTestReadDirEmpty(t *testing.T) (testResults []result) {
 func setupTestReadDirFiles(t *testing.T) (testResults []result) {
 	dir := t.TempDir()
 	entries := []string{}
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		name := fmt.Sprintf("file-%d", i)
 		if err := os.WriteFile(filepath.Join(dir, name), []byte{}, os.ModePerm); err != nil {
 			// For cleanup, its required to add these entries into test results.
@@ -102,7 +102,7 @@ func setupTestReadDirGeneric(t *testing.T) (testResults []result) {
 		t.Fatalf("Unable to create prefix directory \"mydir\", %s", err)
 	}
 	entries := []string{"mydir/"}
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		name := fmt.Sprintf("file-%d", i)
 		if err := os.WriteFile(filepath.Join(dir, "mydir", name), []byte{}, os.ModePerm); err != nil {
 			// For cleanup, its required to add these entries into test results.
@@ -126,7 +126,7 @@ func setupTestReadDirSymlink(t *testing.T) (testResults []result) {
 	}
 	dir := t.TempDir()
 	entries := []string{}
-	for i := 0; i < 10; i++ {
+	for i := range 10 {
 		name1 := fmt.Sprintf("file-%d", i)
 		name2 := fmt.Sprintf("file-%d", i+10)
 		if err := os.WriteFile(filepath.Join(dir, name1), []byte{}, os.ModePerm); err != nil {

cmd/speedtest.go

@@ -102,7 +102,7 @@ func objectSpeedTest(ctx context.Context, opts speedTestOpts) chan madmin.SpeedT
 			var totalUploadTimes madmin.TimeDurations
 			var totalDownloadTimes madmin.TimeDurations
 			var totalDownloadTTFB madmin.TimeDurations
-			for i := 0; i < len(throughputHighestResults); i++ {
+			for i := range len(throughputHighestResults) {
 				errStr := ""
 				if throughputHighestResults[i].Error != "" {
 					errStr = throughputHighestResults[i].Error

cmd/storage-rest-server.go

@@ -675,7 +675,7 @@ func (s *storageRESTServer) DeleteVersionsHandler(w http.ResponseWriter, r *http
 	versions := make([]FileInfoVersions, totalVersions)
 	decoder := msgpNewReader(r.Body)
 	defer readMsgpReaderPoolPut(decoder)
-	for i := 0; i < totalVersions; i++ {
+	for i := range totalVersions {
 		dst := &versions[i]
 		if err := dst.DecodeMsg(decoder); err != nil {
 			s.writeErrorResponse(w, err)

cmd/utils.go

@@ -851,7 +851,7 @@ func lcp(strs []string, pre bool) string {
 		// compare letters
 		if pre {
 			// prefix, iterate left to right
-			for i := 0; i < maxl; i++ {
+			for i := range maxl {
 				if xfix[i] != str[i] {
 					xfix = xfix[:i]
 					break
@@ -859,7 +859,7 @@ func lcp(strs []string, pre bool) string {
 			}
 		} else {
 			// suffix, iterate right to left
-			for i := 0; i < maxl; i++ {
+			for i := range maxl {
 				xi := xfixl - i - 1
 				si := strl - i - 1
 				if xfix[xi] != str[si] {

cmd/xl-storage-format-v2.go

@@ -846,7 +846,7 @@ func decodeXLHeaders(buf []byte) (versions int, headerV, metaV uint8, b []byte,
 // Any non-nil error is returned.
 func decodeVersions(buf []byte, versions int, fn func(idx int, hdr, meta []byte) error) (err error) {
 	var tHdr, tMeta []byte // Zero copy bytes
-	for i := 0; i < versions; i++ {
+	for i := range versions {
 		tHdr, buf, err = msgp.ReadBytesZC(buf)
 		if err != nil {
 			return err

internal/dsync/drwmutex.go

@@ -381,7 +381,7 @@ func refreshLock(ctx context.Context, ds *Dsync, id, source string, quorum int)
 	lockNotFound, lockRefreshed := 0, 0
 	done := false
 
-	for i := 0; i < len(restClnts); i++ {
+	for range len(restClnts) {
 		select {
 		case refreshResult := <-ch:
 			if refreshResult.offline {

internal/event/targetlist.go

@@ -357,7 +357,7 @@ func (list *TargetList) startSendWorkers(workerCount int) {
 	if err != nil {
 		panic(err)
 	}
-	for i := 0; i < workerCount; i++ {
+	for range workerCount {
 		wk.Take()
 		go func() {
 			defer wk.Give()

internal/grid/connection.go

@@ -1041,7 +1041,7 @@ func (c *Connection) readStream(ctx context.Context, conn net.Conn, cancel conte
 		// Handle merged messages.
 		messages := int(m.Seq)
 		c.inMessages.Add(int64(messages))
-		for i := 0; i < messages; i++ {
+		for range messages {
 			if atomic.LoadUint32((*uint32)(&c.state)) != StateConnected {
 				return
 			}

internal/grid/debug.go

@@ -143,7 +143,7 @@ func (t *TestGrid) WaitAllConnect(ctx context.Context) {
 }
 
 func getHosts(n int) (hosts []string, listeners []net.Listener, err error) {
-	for i := 0; i < n; i++ {
+	for range n {
 		l, err := net.Listen("tcp", "127.0.0.1:0")
 		if err != nil {
 			if l, err = net.Listen("tcp6", "[::1]:0"); err != nil {

internal/grid/muxclient.go

@@ -574,7 +574,7 @@ func (m *muxClient) ack(seq uint32) {
 		return
 	}
 	available := cap(m.outBlock)
-	for i := 0; i < available; i++ {
+	for range available {
 		m.outBlock <- struct{}{}
 	}
 	m.acked = true

internal/grid/muxserver.go

@@ -130,7 +130,7 @@ func newMuxStream(ctx context.Context, msg message, c *Connection, handler Strea
 	// Fill outbound block.
 	// Each token represents a message that can be sent to the client without blocking.
 	// The client will refill the tokens as they confirm delivery of the messages.
-	for i := 0; i < outboundCap; i++ {
+	for range outboundCap {
 		m.outBlock <- struct{}{}
 	}
 

internal/s3select/csv/reader.go

@@ -230,7 +230,7 @@ func (r *Reader) startReaders(newReader func(io.Reader) *csv.Reader) error {
 	}()
 
 	// Start parsers
-	for i := 0; i < runtime.GOMAXPROCS(0); i++ {
+	for range runtime.GOMAXPROCS(0) {
 		go func() {
 			for in := range r.input {
 				if len(in.input) == 0 {

internal/s3select/json/preader.go

@@ -173,7 +173,7 @@ func (r *PReader) startReaders() {
 	}()
 
 	// Start parsers
-	for i := 0; i < runtime.GOMAXPROCS(0); i++ {
+	for range runtime.GOMAXPROCS(0) {
 		go func() {
 			for in := range r.input {
 				if len(in.input) == 0 {

internal/s3select/jstream/decoder.go

@@ -332,7 +332,7 @@ func (d *Decoder) u4() rune {
 	// logic taken from:
 	// github.com/buger/jsonparser/blob/master/escape.go#L20
 	var h [4]int
-	for i := 0; i < 4; i++ {
+	for i := range 4 {
 		c := d.next()
 		switch {
 		case c >= '0' && c <= '9':