Fix eof? to return true when there is no more data to read, even if t…

…he stream is not yet finished See code comments for details Fixes ruby#56
segiddins · Dec 22, 2023 · 6973398 · 6973398
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diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c
@@ -3500,6 3500,14 @@ static VALUE
 rb_gzfile_eof_p(VALUE obj)
 {
  struct gzfile *gz = get_gzfile(obj);
 
  // Similar to Socket/Pipe, we need to check if there is any actual data left,
  // as it is possible that the stream is not finished, but there is no data that
  // would be returned upon reading, so we want to report eof? in that case
  while (!ZSTREAM_IS_FINISHED(&gz->z) && ZSTREAM_BUF_FILLED(&gz->z) == 0) {
  gzfile_read_more(gz, Qnil);
  }
 
  return GZFILE_IS_FINISHED(gz) ? Qtrue : Qfalse;
 }
 
@@ -4830,6 4838,9 @@ Init_zlib(void)
  rb_define_attr(cGzError, "input", 1, 0);
  rb_define_method(cGzError, "inspect", gzfile_error_inspect, 0);
 
  /* The block size in bytes that the gzip file reads from its underlying io */
  rb_define_const(cGzipFile, "READ_SIZE", INT2FIX(GZFILE_READ_SIZE));
 
  cNoFooter = rb_define_class_under(cGzipFile, "NoFooter", cGzError);
  cCRCError = rb_define_class_under(cGzipFile, "CRCError", cGzError);
  cLengthError = rb_define_class_under(cGzipFile,"LengthError",cGzError);

diff --git a/test/zlib/test_zlib.rb b/test/zlib/test_zlib.rb
@@ -1205,6 1205,69 @@ def test_double_close
  }
  end
 
  # Test boundary cases around compressed data where the "final" deflate block is empty,
  # and close to a Zlib::GzipFile::READ_SIZE boundary
  [(Zlib::GzipFile::READ_SIZE - 30)..(Zlib::GzipFile::READ_SIZE - 10), (Zlib::GzipFile::READ_SIZE * 2 - 30)..(Zlib::GzipFile::READ_SIZE * 2 - 10)].flat_map(&:to_a).each do |size|
  contents = "a\n" * (size / 2)
  contents << "\n" if size.odd?
  contents.freeze
 
  s = StringIO.new
  gz = Zlib::GzipWriter.new(s, Zlib::NO_COMPRESSION)
  gz.write contents
  gz.flush
  gz.close
  s = s.string.freeze
 
  sub_test_case("String of length #{size}") do
  [[:readpartial, 500], [:readpartial, 1024], [:readpartial, 2028], [:gets], [:getc], [:getbyte], [:read], [:read, 500], [:read, 1024], [:read, 2048], [:readline], [:readlines], [:readbyte], [:readchar]].each do |method, *args|
  test("#{method}(#{args.join(', ')})") do
  read = "".b
  Zlib::GzipReader.wrap(StringIO.new(s)) do |gzio|
  until gzio.eof?
  part = gzio.send(method, *args)
  refute_nil part
  case part
  when Array then part.each { |e| read << e }
  else read << part
  end
  end
  assert_predicate gzio, :eof?
 
  case method
  when :readbyte, :getbyte
  b = read.bytes.last
  gzio.ungetbyte b
  refute_predicate gzio, :eof?
  assert_equal b, gzio.send(method, *args)
  assert_predicate gzio, :eof?
  when :readchar, :getc
  c = read[-1]
  gzio.ungetc c
  refute_predicate gzio, :eof?
  assert_equal c, gzio.send(method, *args)
  assert_predicate gzio, :eof?
  end
 
  2.times do
  case method
  when :readpartial, :readbyte, :readchar, :readline
  assert_raise(EOFError) { gzio.send(method, *args) }
  when :readlines
  assert_equal [], gzio.send(method, *args)
  when ->(m) { m == :read && args.empty? }
  assert_equal "", gzio.send(method, *args)
  else
  assert_nil gzio.send(method, *args)
  end
  assert_predicate gzio, :eof?
  end
  end
  assert_equal contents, read
  end
  end
  end
  end
  end
 
  class TestZlibGzipWriter < Test::Unit::TestCase