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

   1 package hotline
   2
   3 import (
   4         "bufio"
   5         "bytes"
   6         "encoding/binary"
   7         "errors"
   8         "fmt"
   9         "io"
  10         "path/filepath"
  11         "strings"
  12 )
  13
  14 // FilePathItem represents the file or directory portion of a delimited file path (e.g. foo and bar in "/foo/bar")
  15 // Example bytes:
  16 // 00 00
  17 // 09
  18 // 73 75 62 66 6f 6c 64 65 72  "subfolder"
  19 type FilePathItem struct {
  20         Len  byte
  21         Name []byte
  22 }
  23
  24 const fileItemMinLen = 3
  25
  26 // fileItemScanner implements bufio.SplitFunc for parsing incoming byte slices into complete tokens
  27 func fileItemScanner(data []byte, _ bool) (advance int, token []byte, err error) {
  28         if len(data) < fileItemMinLen {
  29                 return 0, nil, nil
  30         }
  31
  32         advance = fileItemMinLen + int(data[2])
  33         return advance, data[0:advance], nil
  34 }
  35
  36 // Write implements the io.Writer interface for FilePathItem
  37 func (fpi *FilePathItem) Write(b []byte) (n int, err error) {
  38         if len(b) < 3 {
  39                 return n, errors.New("buflen too small")
  40         }
  41         fpi.Len = b[2]
  42         fpi.Name = b[fileItemMinLen : fpi.Len+fileItemMinLen]
  43
  44         return int(fpi.Len) + fileItemMinLen, nil
  45 }
  46
  47 type FilePath struct {
  48         ItemCount [2]byte
  49         Items     []FilePathItem
  50 }
  51
  52 // Write implements io.Writer interface for FilePath
  53 func (fp *FilePath) Write(b []byte) (n int, err error) {
  54         reader := bytes.NewReader(b)
  55         err = binary.Read(reader, binary.BigEndian, &fp.ItemCount)
  56         if err != nil && !errors.Is(err, io.EOF) {
  57                 return n, err
  58         }
  59         if errors.Is(err, io.EOF) {
  60                 return n, nil
  61         }
  62
  63         scanner := bufio.NewScanner(reader)
  64         scanner.Split(fileItemScanner)
  65
  66         for i := 0; i < int(binary.BigEndian.Uint16(fp.ItemCount[:])); i++ {
  67                 var fpi FilePathItem
  68                 scanner.Scan()
  69
  70                 // Make a new []byte slice and copy the scanner bytes to it.  This is critical to avoid a data race as the
  71                 // scanner re-uses the buffer for subsequent scans.
  72                 buf := make([]byte, len(scanner.Bytes()))
  73                 copy(buf, scanner.Bytes())
  74
  75                 if _, err := fpi.Write(buf); err != nil {
  76                         return n, err
  77                 }
  78                 fp.Items = append(fp.Items, fpi)
  79         }
  80
  81         return n, nil
  82 }
  83
  84 // IsDropbox checks if a FilePath matches the special drop box folder type
  85 func (fp *FilePath) IsDropbox() bool {
  86         if fp.Len() == 0 {
  87                 return false
  88         }
  89
  90         return strings.Contains(strings.ToLower(string(fp.Items[fp.Len()-1].Name)), "drop box")
  91 }
  92
  93 func (fp *FilePath) IsUploadDir() bool {
  94         if fp.Len() == 0 {
  95                 return false
  96         }
  97
  98         return strings.Contains(strings.ToLower(string(fp.Items[fp.Len()-1].Name)), "upload")
  99 }
 100
 101 func (fp *FilePath) Len() uint16 {
 102         return binary.BigEndian.Uint16(fp.ItemCount[:])
 103 }
 104
 105 func readPath(fileRoot string, filePath, fileName []byte) (fullPath string, err error) {
 106         var fp FilePath
 107         if filePath != nil {
 108                 if _, err = fp.Write(filePath); err != nil {
 109                         return "", err
 110                 }
 111         }
 112
 113         var subPath string
 114         for _, pathItem := range fp.Items {
 115                 subPath = filepath.Join("/", subPath, string(pathItem.Name))
 116         }
 117
 118         fullPath = filepath.Join(
 119                 fileRoot,
 120                 subPath,
 121                 filepath.Join("/", string(fileName)),
 122         )
 123         fullPath, err = txtDecoder.String(fullPath)
 124         if err != nil {
 125                 return "", fmt.Errorf("invalid filepath encoding: %w", err)
 126         }
 127         return fullPath, nil
 128 }