Lib/plat-mac/applesingle.py

   1 r"""Routines to decode AppleSingle files
   2 """
   3
   4 from warnings import warnpy3k
   5 warnpy3k("In 3.x, the applesingle module is removed.", stacklevel=2)
   6
   7 import struct
   8 import sys
   9 try:
  10     import MacOS
  11     import Carbon.File
  12 except:
  13     class MacOS:
  14         def openrf(path, mode):
  15             return open(path + '.rsrc', mode)
  16         openrf = classmethod(openrf)
  17     class Carbon:
  18         class File:
  19             class FSSpec:
  20                 pass
  21             class FSRef:
  22                 pass
  23             class Alias:
  24                 pass
  25
  26 # all of the errors in this module are really errors in the input
  27 # so I think it should test positive against ValueError.
  28 class Error(ValueError):
  29     pass
  30
  31 # File header format: magic, version, unused, number of entries
  32 AS_HEADER_FORMAT=">LL16sh"
  33 AS_HEADER_LENGTH=26
  34 # The flag words for AppleSingle
  35 AS_MAGIC=0x00051600
  36 AS_VERSION=0x00020000
  37
  38 # Entry header format: id, offset, length
  39 AS_ENTRY_FORMAT=">lll"
  40 AS_ENTRY_LENGTH=12
  41
  42 # The id values
  43 AS_DATAFORK=1
  44 AS_RESOURCEFORK=2
  45 AS_IGNORE=(3,4,5,6,8,9,10,11,12,13,14,15)
  46
  47 class AppleSingle(object):
  48     datafork = None
  49     resourcefork = None
  50
  51     def __init__(self, fileobj, verbose=False):
  52         header = fileobj.read(AS_HEADER_LENGTH)
  53         try:
  54             magic, version, ig, nentry = struct.unpack(AS_HEADER_FORMAT, header)
  55         except ValueError, arg:
  56             raise Error, "Unpack header error: %s" % (arg,)
  57         if verbose:
  58             print 'Magic:   0x%8.8x' % (magic,)
  59             print 'Version: 0x%8.8x' % (version,)
  60             print 'Entries: %d' % (nentry,)
  61         if magic != AS_MAGIC:
  62             raise Error, "Unknown AppleSingle magic number 0x%8.8x" % (magic,)
  63         if version != AS_VERSION:
  64             raise Error, "Unknown AppleSingle version number 0x%8.8x" % (version,)
  65         if nentry <= 0:
  66             raise Error, "AppleSingle file contains no forks"
  67         headers = [fileobj.read(AS_ENTRY_LENGTH) for i in xrange(nentry)]
  68         self.forks = []
  69         for hdr in headers:
  70             try:
  71                 restype, offset, length = struct.unpack(AS_ENTRY_FORMAT, hdr)
  72             except ValueError, arg:
  73                 raise Error, "Unpack entry error: %s" % (arg,)
  74             if verbose:
  75                 print "Fork %d, offset %d, length %d" % (restype, offset, length)
  76             fileobj.seek(offset)
  77             data = fileobj.read(length)
  78             if len(data) != length:
  79                 raise Error, "Short read: expected %d bytes got %d" % (length, len(data))
  80             self.forks.append((restype, data))
  81             if restype == AS_DATAFORK:
  82                 self.datafork = data
  83             elif restype == AS_RESOURCEFORK:
  84                 self.resourcefork = data
  85
  86     def tofile(self, path, resonly=False):
  87         outfile = open(path, 'wb')
  88         data = False
  89         if resonly:
  90             if self.resourcefork is None:
  91                 raise Error, "No resource fork found"
  92             fp = open(path, 'wb')
  93             fp.write(self.resourcefork)
  94             fp.close()
  95         elif (self.resourcefork is None and self.datafork is None):
  96             raise Error, "No useful forks found"
  97         else:
  98             if self.datafork is not None:
  99                 fp = open(path, 'wb')
 100                 fp.write(self.datafork)
 101                 fp.close()
 102             if self.resourcefork is not None:
 103                 fp = MacOS.openrf(path, '*wb')
 104                 fp.write(self.resourcefork)
 105                 fp.close()
 106
 107 def decode(infile, outpath, resonly=False, verbose=False):
 108     """decode(infile, outpath [, resonly=False, verbose=False])
 109
 110     Creates a decoded file from an AppleSingle encoded file.
 111     If resonly is True, then it will create a regular file at
 112     outpath containing only the resource fork from infile.
 113     Otherwise it will create an AppleDouble file at outpath
 114     with the data and resource forks from infile.  On platforms
 115     without the MacOS module, it will create inpath and inpath+'.rsrc'
 116     with the data and resource forks respectively.
 117
 118     """
 119     if not hasattr(infile, 'read'):
 120         if isinstance(infile, Carbon.File.Alias):
 121             infile = infile.ResolveAlias()[0]
 122         if isinstance(infile, (Carbon.File.FSSpec, Carbon.File.FSRef)):
 123             infile = infile.as_pathname()
 124         infile = open(infile, 'rb')
 125
 126     asfile = AppleSingle(infile, verbose=verbose)
 127     asfile.tofile(outpath, resonly=resonly)
 128
 129 def _test():
 130     if len(sys.argv) < 3 or sys.argv[1] == '-r' and len(sys.argv) != 4:
 131         print 'Usage: applesingle.py [-r] applesinglefile decodedfile'
 132         sys.exit(1)
 133     if sys.argv[1] == '-r':
 134         resonly = True
 135         del sys.argv[1]
 136     else:
 137         resonly = False
 138     decode(sys.argv[1], sys.argv[2], resonly=resonly)
 139
 140 if __name__ == '__main__':
 141     _test()