git.r.bdr.sh - rbdr/mobius/blob - hotline/file_transfer.go

   1 package hotline
   2
   3 import (
   4         "bufio"
   5         "crypto/rand"
   6         "encoding/binary"
   7         "errors"
   8         "fmt"
   9         "io"
  10         "io/fs"
  11         "log/slog"
  12         "math"
  13         "os"
  14         "path/filepath"
  15         "slices"
  16         "strings"
  17         "sync"
  18 )
  19
  20 // Folder download actions.  Send by the client to indicate the next action the server should take
  21 // for a folder download.
  22 const (
  23         DlFldrActionSendFile   = 1
  24         DlFldrActionResumeFile = 2
  25         DlFldrActionNextFile   = 3
  26 )
  27
  28 // File transfer types
  29 type FileTransferType uint8
  30
  31 const (
  32         FileDownload   = FileTransferType(0)
  33         FileUpload     = FileTransferType(1)
  34         FolderDownload = FileTransferType(2)
  35         FolderUpload   = FileTransferType(3)
  36         BannerDownload = FileTransferType(4)
  37 )
  38
  39 type FileTransferID [4]byte
  40
  41 type FileTransferMgr interface {
  42         Add(ft *FileTransfer)
  43         Get(id FileTransferID) *FileTransfer
  44         Delete(id FileTransferID)
  45 }
  46
  47 type MemFileTransferMgr struct {
  48         fileTransfers map[FileTransferID]*FileTransfer
  49
  50         mu sync.Mutex
  51 }
  52
  53 func NewMemFileTransferMgr() *MemFileTransferMgr {
  54         return &MemFileTransferMgr{
  55                 fileTransfers: make(map[FileTransferID]*FileTransfer),
  56         }
  57 }
  58
  59 func (ftm *MemFileTransferMgr) Add(ft *FileTransfer) {
  60         ftm.mu.Lock()
  61         defer ftm.mu.Unlock()
  62
  63         _, _ = rand.Read(ft.RefNum[:])
  64
  65         ftm.fileTransfers[ft.RefNum] = ft
  66
  67         ft.ClientConn.ClientFileTransferMgr.Add(ft.Type, ft)
  68 }
  69
  70 func (ftm *MemFileTransferMgr) Get(id FileTransferID) *FileTransfer {
  71         ftm.mu.Lock()
  72         defer ftm.mu.Unlock()
  73
  74         return ftm.fileTransfers[id]
  75 }
  76
  77 func (ftm *MemFileTransferMgr) Delete(id FileTransferID) {
  78         ftm.mu.Lock()
  79         defer ftm.mu.Unlock()
  80
  81         ft := ftm.fileTransfers[id]
  82
  83         ft.ClientConn.ClientFileTransferMgr.Delete(ft.Type, id)
  84
  85         delete(ftm.fileTransfers, id)
  86
  87 }
  88
  89 type FileTransfer struct {
  90         FileRoot         string
  91         FileName         []byte
  92         FilePath         []byte
  93         RefNum           [4]byte
  94         Type             FileTransferType
  95         TransferSize     []byte
  96         FolderItemCount  []byte
  97         FileResumeData   *FileResumeData
  98         Options          []byte
  99         bytesSentCounter *WriteCounter
 100         ClientConn       *ClientConn
 101 }
 102
 103 // WriteCounter counts the number of bytes written to it.
 104 type WriteCounter struct {
 105         mux   sync.Mutex
 106         Total int64 // Total # of bytes written
 107 }
 108
 109 // Write implements the io.Writer interface.
 110 //
 111 // Always completes and never returns an error.
 112 func (wc *WriteCounter) Write(p []byte) (int, error) {
 113         wc.mux.Lock()
 114         defer wc.mux.Unlock()
 115         n := len(p)
 116         wc.Total += int64(n)
 117         return n, nil
 118 }
 119
 120 func (cc *ClientConn) NewFileTransfer(transferType FileTransferType, fileroot string, fileName, filePath, size []byte) *FileTransfer {
 121         ft := &FileTransfer{
 122                 FileName:         fileName,
 123                 FileRoot:         fileroot,
 124                 FilePath:         filePath,
 125                 Type:             transferType,
 126                 TransferSize:     size,
 127                 ClientConn:       cc,
 128                 bytesSentCounter: &WriteCounter{},
 129         }
 130
 131         cc.Server.FileTransferMgr.Add(ft)
 132
 133         return ft
 134 }
 135
 136 // String returns a string representation of a file transfer and its progress for display in the GetInfo window
 137 // Example:
 138 // MasterOfOrionII1.4.0. 0%   197.9M
 139 func (ft *FileTransfer) String() string {
 140         trunc := fmt.Sprintf("%.21s", ft.FileName)
 141         return fmt.Sprintf("%-21s %.3s%%  %6s\n", trunc, ft.percentComplete(), ft.formattedTransferSize())
 142 }
 143
 144 func (ft *FileTransfer) percentComplete() string {
 145         ft.bytesSentCounter.mux.Lock()
 146         defer ft.bytesSentCounter.mux.Unlock()
 147         return fmt.Sprintf(
 148                 "%v",
 149                 math.RoundToEven(float64(ft.bytesSentCounter.Total)/float64(binary.BigEndian.Uint32(ft.TransferSize))*100),
 150         )
 151 }
 152
 153 func (ft *FileTransfer) formattedTransferSize() string {
 154         sizeInKB := float32(binary.BigEndian.Uint32(ft.TransferSize)) / 1024
 155         if sizeInKB >= 1024 {
 156                 return fmt.Sprintf("%.1fM", sizeInKB/1024)
 157         } else {
 158                 return fmt.Sprintf("%.0fK", sizeInKB)
 159         }
 160 }
 161
 162 func (ft *FileTransfer) ItemCount() int {
 163         return int(binary.BigEndian.Uint16(ft.FolderItemCount))
 164 }
 165
 166 type folderUpload struct {
 167         DataSize      [2]byte
 168         IsFolder      [2]byte
 169         PathItemCount [2]byte
 170         FileNamePath  []byte
 171 }
 172
 173 //func (fu *folderUpload) Write(p []byte) (int, error) {
 174 //      if len(p) < 7 {
 175 //              return 0, errors.New("buflen too short")
 176 //      }
 177 //      copy(fu.DataSize[:], p[0:2])
 178 //      copy(fu.IsFolder[:], p[2:4])
 179 //      copy(fu.PathItemCount[:], p[4:6])
 180 //
 181 //      fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes TODO: wat
 182 //      n, err := io.ReadFull(rwc, fu.FileNamePath)
 183 //      if err != nil {
 184 //              return 0, err
 185 //      }
 186 //
 187 //      return n + 6, nil
 188 //}
 189
 190 func (fu *folderUpload) FormattedPath() string {
 191         pathItemLen := binary.BigEndian.Uint16(fu.PathItemCount[:])
 192
 193         var pathSegments []string
 194         pathData := fu.FileNamePath
 195
 196         // TODO: implement scanner interface instead?
 197         for i := uint16(0); i < pathItemLen; i++ {
 198                 segLen := pathData[2]
 199                 pathSegments = append(pathSegments, string(pathData[3:3+segLen]))
 200                 pathData = pathData[3+segLen:]
 201         }
 202
 203         return filepath.Join(pathSegments...)
 204 }
 205
 206 type FileHeader struct {
 207         Size     [2]byte // Total size of FileHeader payload
 208         Type     [2]byte // 0 for file, 1 for dir
 209         FilePath []byte  // encoded file path
 210
 211         readOffset int // Internal offset to track read progress
 212 }
 213
 214 func NewFileHeader(fileName string, isDir bool) FileHeader {
 215         fh := FileHeader{
 216                 FilePath: EncodeFilePath(fileName),
 217         }
 218         if isDir {
 219                 fh.Type = [2]byte{0x00, 0x01}
 220         }
 221
 222         encodedPathLen := uint16(len(fh.FilePath) + len(fh.Type))
 223         binary.BigEndian.PutUint16(fh.Size[:], encodedPathLen)
 224
 225         return fh
 226 }
 227
 228 func (fh *FileHeader) Read(p []byte) (int, error) {
 229         buf := slices.Concat(
 230                 fh.Size[:],
 231                 fh.Type[:],
 232                 fh.FilePath,
 233         )
 234
 235         if fh.readOffset >= len(buf) {
 236                 return 0, io.EOF // All bytes have been read
 237         }
 238
 239         n := copy(p, buf[fh.readOffset:])
 240         fh.readOffset += n
 241
 242         return n, nil
 243 }
 244
 245 func DownloadHandler(w io.Writer, fullPath string, fileTransfer *FileTransfer, fs FileStore, rLogger *slog.Logger, preserveForks bool) error {
 246         //s.Stats.DownloadCounter += 1
 247         //s.Stats.DownloadsInProgress += 1
 248         //defer func() {
 249         //      s.Stats.DownloadsInProgress -= 1
 250         //}()
 251
 252         var dataOffset int64
 253         if fileTransfer.FileResumeData != nil {
 254                 dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.FileResumeData.ForkInfoList[0].DataSize[:]))
 255         }
 256
 257         fw, err := NewFileWrapper(fs, fullPath, 0)
 258         if err != nil {
 259                 return fmt.Errorf("reading file header: %v", err)
 260         }
 261
 262         rLogger.Info("Download file", "filePath", fullPath)
 263
 264         // If file transfer options are included, that means this is a "quick preview" request.  In this case skip sending
 265         // the flat file info and proceed directly to sending the file data.
 266         if fileTransfer.Options == nil {
 267                 if _, err = io.Copy(w, fw.Ffo); err != nil {
 268                         return fmt.Errorf("send flat file object: %v", err)
 269                 }
 270         }
 271
 272         file, err := fw.dataForkReader()
 273         if err != nil {
 274                 return fmt.Errorf("open data fork reader: %v", err)
 275         }
 276
 277         br := bufio.NewReader(file)
 278         if _, err := br.Discard(int(dataOffset)); err != nil {
 279                 return fmt.Errorf("seek to resume offsent: %v", err)
 280         }
 281
 282         if _, err = io.Copy(w, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 283                 return fmt.Errorf("send data fork: %v", err)
 284         }
 285
 286         // If the client requested to resume transfer, do not send the resource fork header.
 287         if fileTransfer.FileResumeData == nil {
 288                 err = binary.Write(w, binary.BigEndian, fw.rsrcForkHeader())
 289                 if err != nil {
 290                         return fmt.Errorf("send resource fork header: %v", err)
 291                 }
 292         }
 293
 294         rFile, _ := fw.rsrcForkFile()
 295         //if err != nil {
 296         //      // return fmt.Errorf("open resource fork file: %v", err)
 297         //}
 298
 299         _, _ = io.Copy(w, io.TeeReader(rFile, fileTransfer.bytesSentCounter))
 300         //if err != nil {
 301         //      // return fmt.Errorf("send resource fork data: %v", err)
 302         //}
 303
 304         return nil
 305 }
 306
 307 func UploadHandler(rwc io.ReadWriter, fullPath string, fileTransfer *FileTransfer, fileStore FileStore, rLogger *slog.Logger, preserveForks bool) error {
 308         var file *os.File
 309
 310         // A file upload has two possible cases:
 311         // 1) Upload a new file
 312         // 2) Resume a partially transferred file
 313         //  We have to infer which case applies by inspecting what is already on the filesystem
 314
 315         // Check for existing file.  If found, do not proceed.  This is an invalid scenario, as the file upload transaction
 316         // handler should have returned an error to the client indicating there was an existing file present.
 317         _, err := os.Stat(fullPath)
 318         if err == nil {
 319                 return fmt.Errorf("existing file found: %s", fullPath)
 320         }
 321         if errors.Is(err, fs.ErrNotExist) {
 322                 // If not found, open or create a new .incomplete file
 323                 file, err = os.OpenFile(fullPath+IncompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 324                 if err != nil {
 325                         return err
 326                 }
 327         }
 328
 329         defer file.Close()
 330
 331         f, err := NewFileWrapper(fileStore, fullPath, 0)
 332         if err != nil {
 333                 return err
 334         }
 335
 336         rLogger.Debug("File upload started", "dstFile", fullPath)
 337
 338         rForkWriter := io.Discard
 339         iForkWriter := io.Discard
 340         if preserveForks {
 341                 rForkWriter, err = f.rsrcForkWriter()
 342                 if err != nil {
 343                         return err
 344                 }
 345
 346                 iForkWriter, err = f.InfoForkWriter()
 347                 if err != nil {
 348                         return err
 349                 }
 350         }
 351
 352         if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 353                 return fmt.Errorf("receive file: %v", err)
 354         }
 355
 356         if err := fileStore.Rename(fullPath+".incomplete", fullPath); err != nil {
 357                 return fmt.Errorf("rename incomplete file: %v", err)
 358         }
 359
 360         rLogger.Info("File upload complete", "dstFile", fullPath)
 361
 362         return nil
 363 }
 364
 365 func DownloadFolderHandler(rwc io.ReadWriter, fullPath string, fileTransfer *FileTransfer, fileStore FileStore, rLogger *slog.Logger, preserveForks bool) error {
 366         // Folder Download flow:
 367         // 1. Get filePath from the transfer
 368         // 2. Iterate over files
 369         // 3. For each fileWrapper:
 370         //       Send fileWrapper header to client
 371         // The client can reply in 3 ways:
 372         //
 373         // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 374         //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 375         //
 376         // 2. If download of a fileWrapper is to be resumed:
 377         //              client sends:
 378         //                      []byte{0x00, 0x02} // download folder action
 379         //                      [2]byte // Resume data size
 380         //                      []byte fileWrapper resume data (see myField_FileResumeData)
 381         //
 382         // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 383         //
 384         // When download is requested (case 2 or 3), server replies with:
 385         //                      [4]byte - fileWrapper size
 386         //                      []byte  - Flattened File Object
 387         //
 388         // After every fileWrapper download, client could request next fileWrapper with:
 389         //                      []byte{0x00, 0x03}
 390         //
 391         // This notifies the server to send the next item header
 392
 393         basePathLen := len(fullPath)
 394
 395         rLogger.Info("Start folder download", "path", fullPath)
 396
 397         nextAction := make([]byte, 2)
 398         if _, err := io.ReadFull(rwc, nextAction); err != nil {
 399                 return err
 400         }
 401
 402         i := 0
 403         err := filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 404                 //s.Stats.DownloadCounter += 1
 405                 i += 1
 406
 407                 if err != nil {
 408                         return err
 409                 }
 410
 411                 // skip dot files
 412                 if strings.HasPrefix(info.Name(), ".") {
 413                         return nil
 414                 }
 415
 416                 hlFile, err := NewFileWrapper(fileStore, path, 0)
 417                 if err != nil {
 418                         return err
 419                 }
 420
 421                 subPath := path[basePathLen+1:]
 422
 423                 if i == 1 {
 424                         return nil
 425                 }
 426
 427                 fileHeader := NewFileHeader(subPath, info.IsDir())
 428                 if _, err := io.Copy(rwc, &fileHeader); err != nil {
 429                         return fmt.Errorf("error sending file header: %w", err)
 430                 }
 431
 432                 // Read the client's Next Action request
 433                 if _, err := io.ReadFull(rwc, nextAction); err != nil {
 434                         return err
 435                 }
 436
 437                 var dataOffset int64
 438
 439                 switch nextAction[1] {
 440                 case DlFldrActionResumeFile:
 441                         // get size of resumeData
 442                         resumeDataByteLen := make([]byte, 2)
 443                         if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
 444                                 return err
 445                         }
 446
 447                         resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
 448                         resumeDataBytes := make([]byte, resumeDataLen)
 449                         if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
 450                                 return err
 451                         }
 452
 453                         var frd FileResumeData
 454                         if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
 455                                 return err
 456                         }
 457                         dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
 458                 case DlFldrActionNextFile:
 459                         // client asked to skip this file
 460                         return nil
 461                 }
 462
 463                 if info.IsDir() {
 464                         return nil
 465                 }
 466
 467                 rLogger.Info("File download started",
 468                         "fileName", info.Name(),
 469                         "TransferSize", fmt.Sprintf("%x", hlFile.Ffo.TransferSize(dataOffset)),
 470                 )
 471
 472                 // Send file size to client
 473                 if _, err := rwc.Write(hlFile.Ffo.TransferSize(dataOffset)); err != nil {
 474                         rLogger.Error(err.Error())
 475                         return fmt.Errorf("error sending file size: %w", err)
 476                 }
 477
 478                 // Send ffo bytes to client
 479                 _, err = io.Copy(rwc, hlFile.Ffo)
 480                 if err != nil {
 481                         return fmt.Errorf("error sending flat file object: %w", err)
 482                 }
 483
 484                 file, err := fileStore.Open(path)
 485                 if err != nil {
 486                         return fmt.Errorf("error opening file: %w", err)
 487                 }
 488
 489                 // wr := bufio.NewWriterSize(rwc, 1460)
 490                 if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
 491                         return fmt.Errorf("error sending file: %w", err)
 492                 }
 493
 494                 if nextAction[1] != 2 && hlFile.Ffo.FlatFileHeader.ForkCount[1] == 3 {
 495                         err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
 496                         if err != nil {
 497                                 return fmt.Errorf("error sending resource fork header: %w", err)
 498                         }
 499
 500                         rFile, err := hlFile.rsrcForkFile()
 501                         if err != nil {
 502                                 return fmt.Errorf("error opening resource fork: %w", err)
 503                         }
 504
 505                         if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 506                                 return fmt.Errorf("error sending resource fork: %w", err)
 507                         }
 508                 }
 509
 510                 // Read the client's Next Action request.  This is always 3, I think?
 511                 if _, err := io.ReadFull(rwc, nextAction); err != nil && err != io.EOF {
 512                         return fmt.Errorf("error reading client next action: %w", err)
 513                 }
 514
 515                 return nil
 516         })
 517
 518         if err != nil {
 519                 return err
 520         }
 521
 522         return nil
 523 }
 524
 525 func UploadFolderHandler(rwc io.ReadWriter, fullPath string, fileTransfer *FileTransfer, fileStore FileStore, rLogger *slog.Logger, preserveForks bool) error {
 526
 527         // Check if the target folder exists.  If not, create it.
 528         if _, err := fileStore.Stat(fullPath); os.IsNotExist(err) {
 529                 if err := fileStore.Mkdir(fullPath, 0777); err != nil {
 530                         return err
 531                 }
 532         }
 533
 534         // Begin the folder upload flow by sending the "next file action" to client
 535         if _, err := rwc.Write([]byte{0, DlFldrActionNextFile}); err != nil {
 536                 return err
 537         }
 538
 539         fileSize := make([]byte, 4)
 540
 541         for i := 0; i < fileTransfer.ItemCount(); i++ {
 542                 //s.Stats.UploadCounter += 1
 543
 544                 var fu folderUpload
 545                 // TODO: implement io.Writer on folderUpload and replace this
 546                 if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
 547                         return err
 548                 }
 549                 if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
 550                         return err
 551                 }
 552                 if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
 553                         return err
 554                 }
 555                 fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes TODO: wat
 556                 if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
 557                         return err
 558                 }
 559
 560                 if fu.IsFolder == [2]byte{0, 1} {
 561                         if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
 562                                 if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
 563                                         return err
 564                                 }
 565                         }
 566
 567                         // Tell client to send next file
 568                         if _, err := rwc.Write([]byte{0, DlFldrActionNextFile}); err != nil {
 569                                 return err
 570                         }
 571                 } else {
 572                         nextAction := DlFldrActionSendFile
 573
 574                         // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
 575                         _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
 576                         if err != nil && !errors.Is(err, fs.ErrNotExist) {
 577                                 return err
 578                         }
 579                         if err == nil {
 580                                 nextAction = DlFldrActionNextFile
 581                         }
 582
 583                         //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
 584                         incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+IncompleteFileSuffix))
 585                         if err != nil && !errors.Is(err, fs.ErrNotExist) {
 586                                 return err
 587                         }
 588                         if err == nil {
 589                                 nextAction = DlFldrActionResumeFile
 590                         }
 591
 592                         if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
 593                                 return err
 594                         }
 595
 596                         switch nextAction {
 597                         case DlFldrActionNextFile:
 598                                 continue
 599                         case DlFldrActionResumeFile:
 600                                 offset := make([]byte, 4)
 601                                 binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
 602
 603                                 file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+IncompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
 604                                 if err != nil {
 605                                         return err
 606                                 }
 607
 608                                 fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
 609
 610                                 b, _ := fileResumeData.BinaryMarshal()
 611
 612                                 bs := make([]byte, 2)
 613                                 binary.BigEndian.PutUint16(bs, uint16(len(b)))
 614
 615                                 if _, err := rwc.Write(append(bs, b...)); err != nil {
 616                                         return err
 617                                 }
 618
 619                                 if _, err := io.ReadFull(rwc, fileSize); err != nil {
 620                                         return err
 621                                 }
 622
 623                                 if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil {
 624                                         rLogger.Error(err.Error())
 625                                 }
 626
 627                                 err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
 628                                 if err != nil {
 629                                         return err
 630                                 }
 631
 632                         case DlFldrActionSendFile:
 633                                 if _, err := io.ReadFull(rwc, fileSize); err != nil {
 634                                         return err
 635                                 }
 636
 637                                 filePath := filepath.Join(fullPath, fu.FormattedPath())
 638
 639                                 hlFile, err := NewFileWrapper(fileStore, filePath, 0)
 640                                 if err != nil {
 641                                         return err
 642                                 }
 643
 644                                 rLogger.Info("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
 645
 646                                 incWriter, err := hlFile.incFileWriter()
 647                                 if err != nil {
 648                                         return err
 649                                 }
 650
 651                                 rForkWriter := io.Discard
 652                                 iForkWriter := io.Discard
 653                                 if preserveForks {
 654                                         iForkWriter, err = hlFile.InfoForkWriter()
 655                                         if err != nil {
 656                                                 return err
 657                                         }
 658
 659                                         rForkWriter, err = hlFile.rsrcForkWriter()
 660                                         if err != nil {
 661                                                 return err
 662                                         }
 663                                 }
 664                                 if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 665                                         return err
 666                                 }
 667
 668                                 if err := os.Rename(filePath+".incomplete", filePath); err != nil {
 669                                         return err
 670                                 }
 671                         }
 672
 673                         // Tell client to send next fileWrapper
 674                         if _, err := rwc.Write([]byte{0, DlFldrActionNextFile}); err != nil {
 675                                 return err
 676                         }
 677                 }
 678         }
 679         rLogger.Info("Folder upload complete")
 680         return nil
 681 }