Add xml:space="preserve" in XML output when appropriate

With current HTML escaping, sometimes we may produce an XML tag like

    <code_block>  </code_block>

Many XML parsers consider these spaces insignificant and strip them
out but we need this. There's actually a test case like this in
spec.txt (search "A code block can have all empty lines as its
content:") and without proper hinting, an external xml->html converter
will fail the spec.

XML standard covers this case. If xml:space is "preserve", then
whitespaces are significant and should be kept. Add this hint for
text, code, code_block, html_inline and html_block tags.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/xml.c b/src/xml.c
index 4898cd2..48674cc 100644
--- a/src/xml.c
+++ b/src/xml.c
@@ -60,7 +60,7 @@ static int S_render_node(cmark_node *node, cmark_event_type ev_type,
     case CMARK_NODE_CODE:
     case CMARK_NODE_HTML_BLOCK:
     case CMARK_NODE_HTML_INLINE:
-      cmark_strbuf_puts(xml, ">");
+      cmark_strbuf_puts(xml, " xml:space=\"preserve\">");
       escape_xml(xml, node->as.literal.data, node->as.literal.len);
       cmark_strbuf_puts(xml, "</");
       cmark_strbuf_puts(xml, cmark_node_get_type_string(node));
@@ -100,7 +100,7 @@ static int S_render_node(cmark_node *node, cmark_event_type ev_type,
         escape_xml(xml, node->as.code.info.data, node->as.code.info.len);
         cmark_strbuf_putc(xml, '"');
       }
-      cmark_strbuf_puts(xml, ">");
+      cmark_strbuf_puts(xml, " xml:space=\"preserve\">");
       escape_xml(xml, node->as.code.literal.data, node->as.code.literal.len);
       cmark_strbuf_puts(xml, "</");
       cmark_strbuf_puts(xml, cmark_node_get_type_string(node));