Fix a parsing problem with little data at startup

* parser.c: inkscape extension loader (and possibly others) feed
  data to the parser very slowly, 0 at start, 4 bytes on first GROW
  and this broke after the fix for
  https://bugzilla.gnome.org/show_bug.cgi?id=566012
  http://git.gnome.org/cgit/libxml2/commit/?id=7e385bd4e28a0cc12b6b26ed178c620e3c3ab8d8
  leading to another bug
  https://bugzilla.redhat.com/show_bug.cgi?id=523002
  this detects the situation and GROW when needed for proper processing.

1 files changed, 5 insertions, 1 deletions

diff --git a/parser.c b/parser.c
index e415339..b41dcc3 100644
--- a/parser.c
+++ b/parser.c
@@ -10130,8 +10130,12 @@ xmlParseDocument(xmlParserCtxtPtr ctxt) {
     /*
      * Check for the XMLDecl in the Prolog.
      * do not GROW here to avoid the detected encoder to decode more
-     * than just the first line
+     * than just the first line, unless the amount of data is really
+     * too small to hold "<?xml version="1.0" encoding="foo"
      */
+    if ((ctxt->input->end - ctxt->input->cur) < 35) {
+       GROW;
+    }
     if ((CMP5(CUR_PTR, '<', '?', 'x', 'm', 'l')) && (IS_BLANK_CH(NXT(5)))) {
 
 	/*