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

   1 package hotline
   2
   3 import (
   4         "encoding/binary"
   5         "os"
   6 )
   7
   8 type flattenedFileObject struct {
   9         FlatFileHeader                FlatFileHeader
  10         FlatFileInformationForkHeader FlatFileInformationForkHeader
  11         FlatFileInformationFork       FlatFileInformationFork
  12         FlatFileDataForkHeader        FlatFileDataForkHeader
  13         FileData                      []byte
  14 }
  15
  16 // FlatFileHeader is the first section of a "Flattened File Object".  All fields have static values.
  17 type FlatFileHeader struct {
  18         Format    [4]byte  // Always "FILP"
  19         Version   [2]byte  // Always 1
  20         RSVD      [16]byte // Always empty zeros
  21         ForkCount [2]byte  // Number of forks
  22 }
  23
  24 // NewFlatFileHeader returns a FlatFileHeader struct
  25 func NewFlatFileHeader() FlatFileHeader {
  26         return FlatFileHeader{
  27                 Format:    [4]byte{0x46, 0x49, 0x4c, 0x50}, // FILP
  28                 Version:   [2]byte{0, 1},
  29                 RSVD:      [16]byte{},
  30                 ForkCount: [2]byte{0, 2},
  31         }
  32 }
  33
  34 // FlatFileInformationForkHeader is the second section of a "Flattened File Object"
  35 type FlatFileInformationForkHeader struct {
  36         ForkType        [4]byte // Always "INFO"
  37         CompressionType [4]byte // Always 0; Compression was never implemented in the Hotline protocol
  38         RSVD            [4]byte // Always zeros
  39         DataSize        [4]byte // Size of the flat file information fork
  40 }
  41
  42 type FlatFileInformationFork struct {
  43         Platform         []byte // Operating System used. ("AMAC" or "MWIN")
  44         TypeSignature    []byte // File type signature
  45         CreatorSignature []byte // File creator signature
  46         Flags            []byte
  47         PlatformFlags    []byte
  48         RSVD             []byte
  49         CreateDate       []byte
  50         ModifyDate       []byte
  51         NameScript       []byte // TODO: what is this?
  52         NameSize         []byte // Length of file name (Maximum 128 characters)
  53         Name             []byte // File name
  54         CommentSize      []byte // Length of file comment
  55         Comment          []byte // File comment
  56 }
  57
  58 func NewFlatFileInformationFork(fileName string, modifyTime []byte) FlatFileInformationFork {
  59         return FlatFileInformationFork{
  60                 Platform:         []byte("AMAC"),                                     // TODO: Remove hardcode to support "AWIN" Platform (maybe?)
  61                 TypeSignature:    []byte(fileTypeFromFilename(fileName).TypeCode),    // TODO: Don't infer types from filename
  62                 CreatorSignature: []byte(fileTypeFromFilename(fileName).CreatorCode), // TODO: Don't infer types from filename
  63                 Flags:            []byte{0, 0, 0, 0},                                 // TODO: What is this?
  64                 PlatformFlags:    []byte{0, 0, 1, 0},                                 // TODO: What is this?
  65                 RSVD:             make([]byte, 32),                                   // Unimplemented in Hotline Protocol
  66                 CreateDate:       modifyTime,                                         // some filesystems don't support createTime
  67                 ModifyDate:       modifyTime,
  68                 NameScript:       make([]byte, 2), // TODO: What is this?
  69                 Name:             []byte(fileName),
  70                 CommentSize:      []byte{0, 0},
  71                 Comment:          []byte{}, // TODO: implement (maybe?)
  72         }
  73 }
  74
  75 // DataSize calculates the size of the flat file information fork, which is
  76 // 72 bytes for the fixed length fields plus the length of the Name + Comment
  77 func (ffif *FlatFileInformationFork) DataSize() []byte {
  78         size := make([]byte, 4)
  79
  80         // TODO: Can I do math directly on two byte slices?
  81         dataSize := len(ffif.Name) + len(ffif.Comment) + 74
  82
  83         binary.BigEndian.PutUint32(size, uint32(dataSize))
  84
  85         return size
  86 }
  87
  88 func (ffo *flattenedFileObject) TransferSize() []byte {
  89         payloadSize := len(ffo.BinaryMarshal())
  90         dataSize := binary.BigEndian.Uint32(ffo.FlatFileDataForkHeader.DataSize[:])
  91
  92         transferSize := make([]byte, 4)
  93         binary.BigEndian.PutUint32(transferSize, dataSize+uint32(payloadSize))
  94
  95         return transferSize
  96 }
  97
  98 func (ffif *FlatFileInformationFork) ReadNameSize() []byte {
  99         size := make([]byte, 2)
 100         binary.BigEndian.PutUint16(size, uint16(len(ffif.Name)))
 101
 102         return size
 103 }
 104
 105 type FlatFileDataForkHeader struct {
 106         ForkType        [4]byte
 107         CompressionType [4]byte
 108         RSVD            [4]byte
 109         DataSize        [4]byte
 110 }
 111
 112 func (ffif *FlatFileInformationFork) UnmarshalBinary(b []byte) error {
 113
 114         nameSize := b[70:72]
 115         bs := binary.BigEndian.Uint16(nameSize)
 116
 117         nameEnd := 72 + bs
 118
 119         commentSize := b[nameEnd : nameEnd+2]
 120         commentLen := binary.BigEndian.Uint16(commentSize)
 121
 122         commentStartPos := int(nameEnd) + 2
 123         commentEndPos := int(nameEnd) + 2 + int(commentLen)
 124
 125         comment := b[commentStartPos:commentEndPos]
 126
 127         ffif.Platform = b[0:4]
 128         ffif.TypeSignature = b[4:8]
 129         ffif.CreatorSignature = b[8:12]
 130         ffif.Flags = b[12:16]
 131         ffif.PlatformFlags = b[16:20]
 132         ffif.RSVD = b[20:52]
 133         ffif.CreateDate = b[52:60]
 134         ffif.ModifyDate = b[60:68]
 135         ffif.NameScript = b[68:70]
 136         ffif.NameSize = b[70:72]
 137         ffif.Name = b[72:nameEnd]
 138         ffif.CommentSize = b[nameEnd : nameEnd+2]
 139         ffif.Comment = comment
 140
 141         return nil
 142 }
 143
 144 func (f *flattenedFileObject) BinaryMarshal() []byte {
 145         var out []byte
 146         out = append(out, f.FlatFileHeader.Format[:]...)
 147         out = append(out, f.FlatFileHeader.Version[:]...)
 148         out = append(out, f.FlatFileHeader.RSVD[:]...)
 149         out = append(out, f.FlatFileHeader.ForkCount[:]...)
 150
 151         out = append(out, []byte("INFO")...)
 152         out = append(out, []byte{0, 0, 0, 0}...)
 153         out = append(out, make([]byte, 4)...)
 154         out = append(out, f.FlatFileInformationFork.DataSize()...)
 155
 156         out = append(out, f.FlatFileInformationFork.Platform...)
 157         out = append(out, f.FlatFileInformationFork.TypeSignature...)
 158         out = append(out, f.FlatFileInformationFork.CreatorSignature...)
 159         out = append(out, f.FlatFileInformationFork.Flags...)
 160         out = append(out, f.FlatFileInformationFork.PlatformFlags...)
 161         out = append(out, f.FlatFileInformationFork.RSVD...)
 162         out = append(out, f.FlatFileInformationFork.CreateDate...)
 163         out = append(out, f.FlatFileInformationFork.ModifyDate...)
 164         out = append(out, f.FlatFileInformationFork.NameScript...)
 165         out = append(out, f.FlatFileInformationFork.ReadNameSize()...)
 166         out = append(out, f.FlatFileInformationFork.Name...)
 167         out = append(out, f.FlatFileInformationFork.CommentSize...)
 168         out = append(out, f.FlatFileInformationFork.Comment...)
 169
 170         out = append(out, f.FlatFileDataForkHeader.ForkType[:]...)
 171         out = append(out, f.FlatFileDataForkHeader.CompressionType[:]...)
 172         out = append(out, f.FlatFileDataForkHeader.RSVD[:]...)
 173         out = append(out, f.FlatFileDataForkHeader.DataSize[:]...)
 174
 175         return out
 176 }
 177
 178 func NewFlattenedFileObject(fileRoot string, filePath, fileName []byte, dataOffset int64) (*flattenedFileObject, error) {
 179         fullFilePath, err := readPath(fileRoot, filePath, fileName)
 180         if err != nil {
 181                 return nil, err
 182         }
 183         file, err := effectiveFile(fullFilePath)
 184         if err != nil {
 185                 return nil, err
 186         }
 187
 188         defer func(file *os.File) { _ = file.Close() }(file)
 189
 190         fileInfo, err := file.Stat()
 191         if err != nil {
 192                 return nil, err
 193         }
 194
 195         dataSize := make([]byte, 4)
 196         binary.BigEndian.PutUint32(dataSize, uint32(fileInfo.Size()-dataOffset))
 197
 198         mTime := toHotlineTime(fileInfo.ModTime())
 199
 200         return &flattenedFileObject{
 201                 FlatFileHeader:          NewFlatFileHeader(),
 202                 FlatFileInformationFork: NewFlatFileInformationFork(string(fileName), mTime),
 203                 FlatFileDataForkHeader: FlatFileDataForkHeader{
 204                         ForkType:        [4]byte{0x44, 0x41, 0x54, 0x41}, // "DATA"
 205                         CompressionType: [4]byte{},
 206                         RSVD:            [4]byte{},
 207                         DataSize:        [4]byte{dataSize[0], dataSize[1], dataSize[2], dataSize[3]},
 208                 },
 209         }, nil
 210 }