lib/git/raw/internal/loose.rb

   1 require 'zlib'
   2 require 'digest/sha1'
   3
   4 require 'git/raw/internal/object'
   5
   6 module Git
   7   module Raw
   8     module Internal
   9       class LooseObjectError < StandardError
  10       end
  11
  12       class LooseStorage
  13         def initialize(directory)
  14           @directory = directory
  15         end
  16
  17         def [](sha1)
  18           sha1 = sha1.unpack("H*")[0]
  19
  20           path = @directory+'/'+sha1[0...2]+'/'+sha1[2..40]
  21           begin
  22             get_raw_object(File.read(path))
  23           rescue Errno::ENOENT
  24             nil
  25           end
  26         end
  27
  28         def get_raw_object(buf)
  29           if buf.length < 2
  30             raise LooseObjectError, "object file too small"
  31           end
  32
  33           if legacy_loose_object?(buf)
  34             content = Zlib::Inflate.inflate(buf)
  35             header, content = content.split(/\0/, 2)
  36             if !header || !content
  37               raise LooseObjectError, "invalid object header"
  38             end
  39             type, size = header.split(/ /, 2)
  40             if !%w(blob tree commit tag).include?(type) || size !~ /^\d+$/
  41               raise LooseObjectError, "invalid object header"
  42             end
  43             type = type.to_sym
  44             size = size.to_i
  45           else
  46             type, size, used = unpack_object_header_gently(buf)
  47             content = Zlib::Inflate.inflate(buf[used..-1])
  48           end
  49           raise LooseObjectError, "size mismatch" if content.length != size
  50           return RawObject.new(type, content)
  51         end
  52
  53         # private
  54         def unpack_object_header_gently(buf)
  55           used = 0
  56           c = buf[used]
  57           used += 1
  58
  59           type = (c >> 4) & 7;
  60           size = c & 15;
  61           shift = 4;
  62           while c & 0x80 != 0
  63             if buf.length <= used
  64               raise LooseObjectError, "object file too short"
  65             end
  66             c = buf[used]
  67             used += 1
  68
  69             size += (c & 0x7f) << shift
  70             shift += 7
  71           end
  72           type = OBJ_TYPES[type]
  73           if ![:blob, :tree, :commit, :tag].include?(type)
  74             raise LooseObjectError, "invalid loose object type"
  75           end
  76           return [type, size, used]
  77         end
  78         private :unpack_object_header_gently
  79
  80         def legacy_loose_object?(buf)
  81           word = (buf[0] << 8) + buf[1]
  82           buf[0] == 0x78 && word % 31 == 0
  83         end
  84         private :legacy_loose_object?
  85       end
  86     end
  87   end
  88 end
  89
  90 if $0 == __FILE__
  91   require 'find'
  92   ARGV.each do |path|
  93     storage = Git::Internal::LooseStorage.new(path)
  94     Find.find(path) do |p|
  95       next if !/\/([0-9a-f]{2})\/([0-9a-f]{38})$/.match(p)
  96       obj = storage[[$1+$2].pack("H*")]
  97       puts "%s %s" % [obj.sha1.unpack("H*")[0], obj.type]
  98     end
  99   end
 100 end