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         FileName         []byte
  91         FilePath         []byte
  92         RefNum           [4]byte
  93         Type             FileTransferType
  94         TransferSize     []byte
  95         FolderItemCount  []byte
  96         FileResumeData   *FileResumeData
  97         Options          []byte
  98         bytesSentCounter *WriteCounter
  99         ClientConn       *ClientConn
 100 }
 101
 102 // WriteCounter counts the number of bytes written to it.
 103 type WriteCounter struct {
 104         mux   sync.Mutex
 105         Total int64 // Total # of bytes written
 106 }
 107
 108 // Write implements the io.Writer interface.
 109 //
 110 // Always completes and never returns an error.
 111 func (wc *WriteCounter) Write(p []byte) (int, error) {
 112         wc.mux.Lock()
 113         defer wc.mux.Unlock()
 114         n := len(p)
 115         wc.Total += int64(n)
 116         return n, nil
 117 }
 118
 119 func (cc *ClientConn) NewFileTransfer(transferType FileTransferType, fileName, filePath, size []byte) *FileTransfer {
 120         ft := &FileTransfer{
 121                 FileName:         fileName,
 122                 FilePath:         filePath,
 123                 Type:             transferType,
 124                 TransferSize:     size,
 125                 ClientConn:       cc,
 126                 bytesSentCounter: &WriteCounter{},
 127         }
 128
 129         cc.Server.FileTransferMgr.Add(ft)
 130
 131         return ft
 132 }
 133
 134 // String returns a string representation of a file transfer and its progress for display in the GetInfo window
 135 // Example:
 136 // MasterOfOrionII1.4.0. 0%   197.9M
 137 func (ft *FileTransfer) String() string {
 138         trunc := fmt.Sprintf("%.21s", ft.FileName)
 139         return fmt.Sprintf("%-21s %.3s%%  %6s\n", trunc, ft.percentComplete(), ft.formattedTransferSize())
 140 }
 141
 142 func (ft *FileTransfer) percentComplete() string {
 143         ft.bytesSentCounter.mux.Lock()
 144         defer ft.bytesSentCounter.mux.Unlock()
 145         return fmt.Sprintf(
 146                 "%v",
 147                 math.RoundToEven(float64(ft.bytesSentCounter.Total)/float64(binary.BigEndian.Uint32(ft.TransferSize))*100),
 148         )
 149 }
 150
 151 func (ft *FileTransfer) formattedTransferSize() string {
 152         sizeInKB := float32(binary.BigEndian.Uint32(ft.TransferSize)) / 1024
 153         if sizeInKB >= 1024 {
 154                 return fmt.Sprintf("%.1fM", sizeInKB/1024)
 155         } else {
 156                 return fmt.Sprintf("%.0fK", sizeInKB)
 157         }
 158 }
 159
 160 func (ft *FileTransfer) ItemCount() int {
 161         return int(binary.BigEndian.Uint16(ft.FolderItemCount))
 162 }
 163
 164 type folderUpload struct {
 165         DataSize      [2]byte
 166         IsFolder      [2]byte
 167         PathItemCount [2]byte
 168         FileNamePath  []byte
 169 }
 170
 171 //func (fu *folderUpload) Write(p []byte) (int, error) {
 172 //      if len(p) < 7 {
 173 //              return 0, errors.New("buflen too short")
 174 //      }
 175 //      copy(fu.DataSize[:], p[0:2])
 176 //      copy(fu.IsFolder[:], p[2:4])
 177 //      copy(fu.PathItemCount[:], p[4:6])
 178 //
 179 //      fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes TODO: wat
 180 //      n, err := io.ReadFull(rwc, fu.FileNamePath)
 181 //      if err != nil {
 182 //              return 0, err
 183 //      }
 184 //
 185 //      return n + 6, nil
 186 //}
 187
 188 func (fu *folderUpload) FormattedPath() string {
 189         pathItemLen := binary.BigEndian.Uint16(fu.PathItemCount[:])
 190
 191         var pathSegments []string
 192         pathData := fu.FileNamePath
 193
 194         // TODO: implement scanner interface instead?
 195         for i := uint16(0); i < pathItemLen; i++ {
 196                 segLen := pathData[2]
 197                 pathSegments = append(pathSegments, string(pathData[3:3+segLen]))
 198                 pathData = pathData[3+segLen:]
 199         }
 200
 201         return filepath.Join(pathSegments...)
 202 }
 203
 204 type FileHeader struct {
 205         Size     [2]byte // Total size of FileHeader payload
 206         Type     [2]byte // 0 for file, 1 for dir
 207         FilePath []byte  // encoded file path
 208
 209         readOffset int // Internal offset to track read progress
 210 }
 211
 212 func NewFileHeader(fileName string, isDir bool) FileHeader {
 213         fh := FileHeader{
 214                 FilePath: EncodeFilePath(fileName),
 215         }
 216         if isDir {
 217                 fh.Type = [2]byte{0x00, 0x01}
 218         }
 219
 220         encodedPathLen := uint16(len(fh.FilePath) + len(fh.Type))
 221         binary.BigEndian.PutUint16(fh.Size[:], encodedPathLen)
 222
 223         return fh
 224 }
 225
 226 func (fh *FileHeader) Read(p []byte) (int, error) {
 227         buf := slices.Concat(
 228                 fh.Size[:],
 229                 fh.Type[:],
 230                 fh.FilePath,
 231         )
 232
 233         if fh.readOffset >= len(buf) {
 234                 return 0, io.EOF // All bytes have been read
 235         }
 236
 237         n := copy(p, buf[fh.readOffset:])
 238         fh.readOffset += n
 239
 240         return n, nil
 241 }
 242
 243 func DownloadHandler(w io.Writer, fullPath string, fileTransfer *FileTransfer, fs FileStore, rLogger *slog.Logger, preserveForks bool) error {
 244         //s.Stats.DownloadCounter += 1
 245         //s.Stats.DownloadsInProgress += 1
 246         //defer func() {
 247         //      s.Stats.DownloadsInProgress -= 1
 248         //}()
 249
 250         var dataOffset int64
 251         if fileTransfer.FileResumeData != nil {
 252                 dataOffset = int64(binary.BigEndian.Uint32(fileTransfer.FileResumeData.ForkInfoList[0].DataSize[:]))
 253         }
 254
 255         fw, err := NewFileWrapper(fs, fullPath, 0)
 256         if err != nil {
 257                 return fmt.Errorf("reading file header: %v", err)
 258         }
 259
 260         rLogger.Info("Download file", "filePath", fullPath)
 261
 262         // If file transfer options are included, that means this is a "quick preview" request.  In this case skip sending
 263         // the flat file info and proceed directly to sending the file data.
 264         if fileTransfer.Options == nil {
 265                 if _, err = io.Copy(w, fw.Ffo); err != nil {
 266                         return fmt.Errorf("send flat file object: %v", err)
 267                 }
 268         }
 269
 270         file, err := fw.dataForkReader()
 271         if err != nil {
 272                 return fmt.Errorf("open data fork reader: %v", err)
 273         }
 274
 275         br := bufio.NewReader(file)
 276         if _, err := br.Discard(int(dataOffset)); err != nil {
 277                 return fmt.Errorf("seek to resume offsent: %v", err)
 278         }
 279
 280         if _, err = io.Copy(w, io.TeeReader(br, fileTransfer.bytesSentCounter)); err != nil {
 281                 return fmt.Errorf("send data fork: %v", err)
 282         }
 283
 284         // If the client requested to resume transfer, do not send the resource fork header.
 285         if fileTransfer.FileResumeData == nil {
 286                 err = binary.Write(w, binary.BigEndian, fw.rsrcForkHeader())
 287                 if err != nil {
 288                         return fmt.Errorf("send resource fork header: %v", err)
 289                 }
 290         }
 291
 292         rFile, err := fw.rsrcForkFile()
 293         if err != nil {
 294                 // return fmt.Errorf("open resource fork file: %v", err)
 295         }
 296
 297         if _, err = io.Copy(w, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 298                 // return fmt.Errorf("send resource fork data: %v", err)
 299         }
 300
 301         return nil
 302 }
 303
 304 func UploadHandler(rwc io.ReadWriter, fullPath string, fileTransfer *FileTransfer, fileStore FileStore, rLogger *slog.Logger, preserveForks bool) error {
 305         var file *os.File
 306
 307         // A file upload has two possible cases:
 308         // 1) Upload a new file
 309         // 2) Resume a partially transferred file
 310         //  We have to infer which case applies by inspecting what is already on the filesystem
 311
 312         // Check for existing file.  If found, do not proceed.  This is an invalid scenario, as the file upload transaction
 313         // handler should have returned an error to the client indicating there was an existing file present.
 314         _, err := os.Stat(fullPath)
 315         if err == nil {
 316                 return fmt.Errorf("existing file found: %s", fullPath)
 317         }
 318         if errors.Is(err, fs.ErrNotExist) {
 319                 // If not found, open or create a new .incomplete file
 320                 file, err = os.OpenFile(fullPath+IncompleteFileSuffix, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
 321                 if err != nil {
 322                         return err
 323                 }
 324         }
 325
 326         f, err := NewFileWrapper(fileStore, fullPath, 0)
 327         if err != nil {
 328                 return err
 329         }
 330
 331         rLogger.Info("File upload started", "dstFile", fullPath)
 332
 333         rForkWriter := io.Discard
 334         iForkWriter := io.Discard
 335         if preserveForks {
 336                 rForkWriter, err = f.rsrcForkWriter()
 337                 if err != nil {
 338                         return err
 339                 }
 340
 341                 iForkWriter, err = f.InfoForkWriter()
 342                 if err != nil {
 343                         return err
 344                 }
 345         }
 346
 347         if err := receiveFile(rwc, file, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 348                 rLogger.Error(err.Error())
 349         }
 350
 351         if err := file.Close(); err != nil {
 352                 return err
 353         }
 354
 355         if err := fileStore.Rename(fullPath+".incomplete", fullPath); err != nil {
 356                 return err
 357         }
 358
 359         rLogger.Info("File upload complete", "dstFile", fullPath)
 360
 361         return nil
 362 }
 363
 364 func DownloadFolderHandler(rwc io.ReadWriter, fullPath string, fileTransfer *FileTransfer, fileStore FileStore, rLogger *slog.Logger, preserveForks bool) error {
 365         // Folder Download flow:
 366         // 1. Get filePath from the transfer
 367         // 2. Iterate over files
 368         // 3. For each fileWrapper:
 369         //       Send fileWrapper header to client
 370         // The client can reply in 3 ways:
 371         //
 372         // 1. If type is an odd number (unknown type?), or fileWrapper download for the current fileWrapper is completed:
 373         //              client sends []byte{0x00, 0x03} to tell the server to continue to the next fileWrapper
 374         //
 375         // 2. If download of a fileWrapper is to be resumed:
 376         //              client sends:
 377         //                      []byte{0x00, 0x02} // download folder action
 378         //                      [2]byte // Resume data size
 379         //                      []byte fileWrapper resume data (see myField_FileResumeData)
 380         //
 381         // 3. Otherwise, download of the fileWrapper is requested and client sends []byte{0x00, 0x01}
 382         //
 383         // When download is requested (case 2 or 3), server replies with:
 384         //                      [4]byte - fileWrapper size
 385         //                      []byte  - Flattened File Object
 386         //
 387         // After every fileWrapper download, client could request next fileWrapper with:
 388         //                      []byte{0x00, 0x03}
 389         //
 390         // This notifies the server to send the next item header
 391
 392         basePathLen := len(fullPath)
 393
 394         rLogger.Info("Start folder download", "path", fullPath)
 395
 396         nextAction := make([]byte, 2)
 397         if _, err := io.ReadFull(rwc, nextAction); err != nil {
 398                 return err
 399         }
 400
 401         i := 0
 402         err := filepath.Walk(fullPath+"/", func(path string, info os.FileInfo, err error) error {
 403                 //s.Stats.DownloadCounter += 1
 404                 i += 1
 405
 406                 if err != nil {
 407                         return err
 408                 }
 409
 410                 // skip dot files
 411                 if strings.HasPrefix(info.Name(), ".") {
 412                         return nil
 413                 }
 414
 415                 hlFile, err := NewFileWrapper(fileStore, path, 0)
 416                 if err != nil {
 417                         return err
 418                 }
 419
 420                 subPath := path[basePathLen+1:]
 421                 rLogger.Debug("Sending fileheader", "i", i, "path", path, "fullFilePath", fullPath, "subPath", subPath, "IsDir", info.IsDir())
 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                 rLogger.Debug("Client folder download action", "action", fmt.Sprintf("%X", nextAction[0:2]))
 438
 439                 var dataOffset int64
 440
 441                 switch nextAction[1] {
 442                 case DlFldrActionResumeFile:
 443                         // get size of resumeData
 444                         resumeDataByteLen := make([]byte, 2)
 445                         if _, err := io.ReadFull(rwc, resumeDataByteLen); err != nil {
 446                                 return err
 447                         }
 448
 449                         resumeDataLen := binary.BigEndian.Uint16(resumeDataByteLen)
 450                         resumeDataBytes := make([]byte, resumeDataLen)
 451                         if _, err := io.ReadFull(rwc, resumeDataBytes); err != nil {
 452                                 return err
 453                         }
 454
 455                         var frd FileResumeData
 456                         if err := frd.UnmarshalBinary(resumeDataBytes); err != nil {
 457                                 return err
 458                         }
 459                         dataOffset = int64(binary.BigEndian.Uint32(frd.ForkInfoList[0].DataSize[:]))
 460                 case DlFldrActionNextFile:
 461                         // client asked to skip this file
 462                         return nil
 463                 }
 464
 465                 if info.IsDir() {
 466                         return nil
 467                 }
 468
 469                 rLogger.Info("File download started",
 470                         "fileName", info.Name(),
 471                         "TransferSize", fmt.Sprintf("%x", hlFile.Ffo.TransferSize(dataOffset)),
 472                 )
 473
 474                 // Send file size to client
 475                 if _, err := rwc.Write(hlFile.Ffo.TransferSize(dataOffset)); err != nil {
 476                         rLogger.Error(err.Error())
 477                         return fmt.Errorf("error sending file size: %w", err)
 478                 }
 479
 480                 // Send ffo bytes to client
 481                 _, err = io.Copy(rwc, hlFile.Ffo)
 482                 if err != nil {
 483                         return fmt.Errorf("error sending flat file object: %w", err)
 484                 }
 485
 486                 file, err := fileStore.Open(path)
 487                 if err != nil {
 488                         return fmt.Errorf("error opening file: %w", err)
 489                 }
 490
 491                 // wr := bufio.NewWriterSize(rwc, 1460)
 492                 if _, err = io.Copy(rwc, io.TeeReader(file, fileTransfer.bytesSentCounter)); err != nil {
 493                         return fmt.Errorf("error sending file: %w", err)
 494                 }
 495
 496                 if nextAction[1] != 2 && hlFile.Ffo.FlatFileHeader.ForkCount[1] == 3 {
 497                         err = binary.Write(rwc, binary.BigEndian, hlFile.rsrcForkHeader())
 498                         if err != nil {
 499                                 return fmt.Errorf("error sending resource fork header: %w", err)
 500                         }
 501
 502                         rFile, err := hlFile.rsrcForkFile()
 503                         if err != nil {
 504                                 return fmt.Errorf("error opening resource fork: %w", err)
 505                         }
 506
 507                         if _, err = io.Copy(rwc, io.TeeReader(rFile, fileTransfer.bytesSentCounter)); err != nil {
 508                                 return fmt.Errorf("error sending resource fork: %w", err)
 509                         }
 510                 }
 511
 512                 // Read the client's Next Action request.  This is always 3, I think?
 513                 if _, err := io.ReadFull(rwc, nextAction); err != nil && err != io.EOF {
 514                         return fmt.Errorf("error reading client next action: %w", err)
 515                 }
 516
 517                 return nil
 518         })
 519
 520         if err != nil {
 521                 return err
 522         }
 523
 524         return nil
 525 }
 526
 527 func UploadFolderHandler(rwc io.ReadWriter, fullPath string, fileTransfer *FileTransfer, fileStore FileStore, rLogger *slog.Logger, preserveForks bool) error {
 528
 529         // Check if the target folder exists.  If not, create it.
 530         if _, err := fileStore.Stat(fullPath); os.IsNotExist(err) {
 531                 if err := fileStore.Mkdir(fullPath, 0777); err != nil {
 532                         return err
 533                 }
 534         }
 535
 536         // Begin the folder upload flow by sending the "next file action" to client
 537         if _, err := rwc.Write([]byte{0, DlFldrActionNextFile}); err != nil {
 538                 return err
 539         }
 540
 541         fileSize := make([]byte, 4)
 542
 543         for i := 0; i < fileTransfer.ItemCount(); i++ {
 544                 //s.Stats.UploadCounter += 1
 545
 546                 var fu folderUpload
 547                 // TODO: implement io.Writer on folderUpload and replace this
 548                 if _, err := io.ReadFull(rwc, fu.DataSize[:]); err != nil {
 549                         return err
 550                 }
 551                 if _, err := io.ReadFull(rwc, fu.IsFolder[:]); err != nil {
 552                         return err
 553                 }
 554                 if _, err := io.ReadFull(rwc, fu.PathItemCount[:]); err != nil {
 555                         return err
 556                 }
 557                 fu.FileNamePath = make([]byte, binary.BigEndian.Uint16(fu.DataSize[:])-4) // -4 to subtract the path separator bytes TODO: wat
 558                 if _, err := io.ReadFull(rwc, fu.FileNamePath); err != nil {
 559                         return err
 560                 }
 561
 562                 if fu.IsFolder == [2]byte{0, 1} {
 563                         if _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath())); os.IsNotExist(err) {
 564                                 if err := os.Mkdir(filepath.Join(fullPath, fu.FormattedPath()), 0777); err != nil {
 565                                         return err
 566                                 }
 567                         }
 568
 569                         // Tell client to send next file
 570                         if _, err := rwc.Write([]byte{0, DlFldrActionNextFile}); err != nil {
 571                                 return err
 572                         }
 573                 } else {
 574                         nextAction := DlFldrActionSendFile
 575
 576                         // Check if we have the full file already.  If so, send dlFldrAction_NextFile to client to skip.
 577                         _, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()))
 578                         if err != nil && !errors.Is(err, fs.ErrNotExist) {
 579                                 return err
 580                         }
 581                         if err == nil {
 582                                 nextAction = DlFldrActionNextFile
 583                         }
 584
 585                         //  Check if we have a partial file already.  If so, send dlFldrAction_ResumeFile to client to resume upload.
 586                         incompleteFile, err := os.Stat(filepath.Join(fullPath, fu.FormattedPath()+IncompleteFileSuffix))
 587                         if err != nil && !errors.Is(err, fs.ErrNotExist) {
 588                                 return err
 589                         }
 590                         if err == nil {
 591                                 nextAction = DlFldrActionResumeFile
 592                         }
 593
 594                         if _, err := rwc.Write([]byte{0, uint8(nextAction)}); err != nil {
 595                                 return err
 596                         }
 597
 598                         switch nextAction {
 599                         case DlFldrActionNextFile:
 600                                 continue
 601                         case DlFldrActionResumeFile:
 602                                 offset := make([]byte, 4)
 603                                 binary.BigEndian.PutUint32(offset, uint32(incompleteFile.Size()))
 604
 605                                 file, err := os.OpenFile(fullPath+"/"+fu.FormattedPath()+IncompleteFileSuffix, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
 606                                 if err != nil {
 607                                         return err
 608                                 }
 609
 610                                 fileResumeData := NewFileResumeData([]ForkInfoList{*NewForkInfoList(offset)})
 611
 612                                 b, _ := fileResumeData.BinaryMarshal()
 613
 614                                 bs := make([]byte, 2)
 615                                 binary.BigEndian.PutUint16(bs, uint16(len(b)))
 616
 617                                 if _, err := rwc.Write(append(bs, b...)); err != nil {
 618                                         return err
 619                                 }
 620
 621                                 if _, err := io.ReadFull(rwc, fileSize); err != nil {
 622                                         return err
 623                                 }
 624
 625                                 if err := receiveFile(rwc, file, io.Discard, io.Discard, fileTransfer.bytesSentCounter); err != nil {
 626                                         rLogger.Error(err.Error())
 627                                 }
 628
 629                                 err = os.Rename(fullPath+"/"+fu.FormattedPath()+".incomplete", fullPath+"/"+fu.FormattedPath())
 630                                 if err != nil {
 631                                         return err
 632                                 }
 633
 634                         case DlFldrActionSendFile:
 635                                 if _, err := io.ReadFull(rwc, fileSize); err != nil {
 636                                         return err
 637                                 }
 638
 639                                 filePath := filepath.Join(fullPath, fu.FormattedPath())
 640
 641                                 hlFile, err := NewFileWrapper(fileStore, filePath, 0)
 642                                 if err != nil {
 643                                         return err
 644                                 }
 645
 646                                 rLogger.Info("Starting file transfer", "path", filePath, "fileNum", i+1, "fileSize", binary.BigEndian.Uint32(fileSize))
 647
 648                                 incWriter, err := hlFile.incFileWriter()
 649                                 if err != nil {
 650                                         return err
 651                                 }
 652
 653                                 rForkWriter := io.Discard
 654                                 iForkWriter := io.Discard
 655                                 if preserveForks {
 656                                         iForkWriter, err = hlFile.InfoForkWriter()
 657                                         if err != nil {
 658                                                 return err
 659                                         }
 660
 661                                         rForkWriter, err = hlFile.rsrcForkWriter()
 662                                         if err != nil {
 663                                                 return err
 664                                         }
 665                                 }
 666                                 if err := receiveFile(rwc, incWriter, rForkWriter, iForkWriter, fileTransfer.bytesSentCounter); err != nil {
 667                                         return err
 668                                 }
 669
 670                                 if err := os.Rename(filePath+".incomplete", filePath); err != nil {
 671                                         return err
 672                                 }
 673                         }
 674
 675                         // Tell client to send next fileWrapper
 676                         if _, err := rwc.Write([]byte{0, DlFldrActionNextFile}); err != nil {
 677                                 return err
 678                         }
 679                 }
 680         }
 681         rLogger.Info("Folder upload complete")
 682         return nil
 683 }