ender672 · December 8, 2011 23:42
diff --git a/gistfile1.rb b/gistfile1.rb
 require 'nokogiri'

 html = '<html><body><br/></body></html>'

 # Nokogiri's new HTML encoding detection uses a custom SAX document handler to
 # "peek" at an IO before parsing it.
 #
 # It interrupts the SAX parser by throwing from the context of a SAX document
 # handler callback:
 # https://github.com/tenderlove/nokogiri/blob/master/lib/nokogiri/html/document.rb#L144
 #
 # This causes a memory leak since the libxml2 parser does not expect its
 # callbacks to longjump. Nokogiri leaks a little bit of memory every time we
 # open an HTML document from an IO.

 loop do
  doc = Nokogiri::HTML::Document::EncodingReader::SAXHandler.new(:foo)
  prs = Nokogiri::HTML::SAX::Parser.new(doc)
  ctx = Nokogiri::HTML::SAX::ParserContext.memory(html, 'UTF-8')
  catch(:foo) do
    ctx.parse_with(prs)
  end
 end

 # The above shows what is going on behind the scenes. Here is a much easier way
 # to trigger this memory leak:
 loop{ Nokogiri::HTML(StringIO.new(html)) }

 # The proper fix for this issue is intrusive. I am unsure if we want to
 # incorporate it into a stable release. It involves wrapping every rb_funcall in
 # xml_sax_parser.c so that it:
 #   * intercepts exceptions and throws
 #   * stashes the exception in a new C struct associated with the handler or the
 #     parser.
 #   * tells libxml2 to stop parsing.
 #   * re-throws the exception after libxml2 finishes its cleanup.
	require 'nokogiri'

	html = '<html><body><br/></body></html>'

	# Nokogiri's new HTML encoding detection uses a custom SAX document handler to
	# "peek" at an IO before parsing it.
	#
	# It interrupts the SAX parser by throwing from the context of a SAX document
	# handler callback:
	# https://github.com/tenderlove/nokogiri/blob/master/lib/nokogiri/html/document.rb#L144
	#
	# This causes a memory leak since the libxml2 parser does not expect its
	# callbacks to longjump. Nokogiri leaks a little bit of memory every time we
	# open an HTML document from an IO.

	loop do
	doc = Nokogiri::HTML::Document::EncodingReader::SAXHandler.new(:foo)
	prs = Nokogiri::HTML::SAX::Parser.new(doc)
	ctx = Nokogiri::HTML::SAX::ParserContext.memory(html, 'UTF-8')
	catch(:foo) do
	ctx.parse_with(prs)
	end
	end

	# The above shows what is going on behind the scenes. Here is a much easier way
	# to trigger this memory leak:
	loop{ Nokogiri::HTML(StringIO.new(html)) }

	# The proper fix for this issue is intrusive. I am unsure if we want to
	# incorporate it into a stable release. It involves wrapping every rb_funcall in
	# xml_sax_parser.c so that it:
	# * intercepts exceptions and throws
	# * stashes the exception in a new C struct associated with the handler or the
	# parser.
	# * tells libxml2 to stop parsing.
	# * re-throws the exception after libxml2 finishes its cleanup.