diff options
Diffstat (limited to 'lib/rubygems/package/tar_reader/entry.rb')
-rw-r--r-- | lib/rubygems/package/tar_reader/entry.rb | 85 |
1 files changed, 82 insertions, 3 deletions
diff --git a/lib/rubygems/package/tar_reader/entry.rb b/lib/rubygems/package/tar_reader/entry.rb index e7b0cd0602..9e7b327431 100644 --- a/lib/rubygems/package/tar_reader/entry.rb +++ b/lib/rubygems/package/tar_reader/entry.rb @@ -9,6 +9,20 @@ class Gem::Package::TarReader::Entry ## + # Creates a new tar entry for +header+ that will be read from +io+ + # If a block is given, the entry is yielded and then closed. + + def self.open(header, io, &block) + entry = new header, io + return entry unless block_given? + begin + yield entry + ensure + entry.close + end + end + + ## # Header for this tar entry attr_reader :header @@ -21,6 +35,7 @@ class Gem::Package::TarReader::Entry @header = header @io = io @orig_pos = @io.pos + @end_pos = @orig_pos + @header.size @read = 0 end @@ -39,7 +54,14 @@ class Gem::Package::TarReader::Entry # Closes the tar entry def close + return if closed? + # Seek to the end of the entry if it wasn't fully read + seek(0, IO::SEEK_END) + # discard trailing zeros + skip = (512 - (@header.size % 512)) % 512 + @io.read(skip) @closed = true + nil end ## @@ -117,6 +139,14 @@ class Gem::Package::TarReader::Entry bytes_read end + ## + # Seek to the position in the tar entry + + def pos=(new_pos) + seek(new_pos, IO::SEEK_SET) + new_pos + end + def size @header.size end @@ -158,12 +188,61 @@ class Gem::Package::TarReader::Entry end ## + # Seeks to +offset+ bytes into the tar file entry + # +whence+ can be IO::SEEK_SET, IO::SEEK_CUR, or IO::SEEK_END + + def seek(offset, whence = IO::SEEK_SET) + check_closed + + new_pos = + case whence + when IO::SEEK_SET then @orig_pos + offset + when IO::SEEK_CUR then @io.pos + offset + when IO::SEEK_END then @end_pos + offset + else + raise ArgumentError, "invalid whence" + end + + if new_pos < @orig_pos + new_pos = @orig_pos + elsif new_pos > @end_pos + new_pos = @end_pos + end + + pending = new_pos - @io.pos + + if @io.respond_to?(:seek) + begin + # avoid reading if the @io supports seeking + @io.seek new_pos, IO::SEEK_SET + pending = 0 + rescue Errno::EINVAL + end + end + + # if seeking isn't supported or failed + # negative seek requires that we rewind and read + if pending < 0 + @io.rewind + pending = new_pos + end + + while pending > 0 do + size_read = @io.read([pending, 4096].min).size + raise UnexpectedEOF if @io.eof? + pending -= size_read + end + + @read = @io.pos - @orig_pos + + 0 + end + + ## # Rewinds to the beginning of the tar file entry def rewind check_closed - - @io.pos = @orig_pos - @read = 0 + seek(0, IO::SEEK_SET) end end |