improve check for stuck XML parser

This fixes regression in parsing some broken documents caused by commit
442b4812cf058481e00c186ef738c990e1a50284 .

Change-Id: Id4afc8b120c72cb77f27c71c3f1452e100f86faf

3 files changed, 47 insertions, 20 deletions

diff --git a/src/lib/ABWParser.cpp b/src/lib/ABWParser.cpp
index 16826e2..db3c68c 100644
--- a/src/lib/ABWParser.cpp
+++ b/src/lib/ABWParser.cpp
@@ -166,12 +166,12 @@ bool libabw::ABWParser::processXmlDocument(librevenge::RVNGInputStream *input)
   if (!input)
     return false;
 
-  ABWXMLErrorWatcher watcher;
+  ABWXMLProgressWatcher watcher;
   auto reader(xmlReaderForStream(input, &watcher));
   if (!reader)
     return false;
   int ret = xmlTextReaderRead(reader.get());
-  while (1 == ret && !watcher.isError())
+  while (1 == ret && !watcher.isStuck())
   {
     processXmlNode(reader.get());
     ret = xmlTextReaderRead(reader.get());
@@ -179,7 +179,7 @@ bool libabw::ABWParser::processXmlDocument(librevenge::RVNGInputStream *input)
 
   if (m_collector)
     m_collector->endDocument();
-  return !watcher.isError();
+  return ret == 1 && !watcher.isStuck();
 }
 
 void libabw::ABWParser::processXmlNode(xmlTextReaderPtr reader)
diff --git a/src/lib/ABWXMLHelper.cpp b/src/lib/ABWXMLHelper.cpp
index 4295c47..fe8638e 100644
--- a/src/lib/ABWXMLHelper.cpp
+++ b/src/lib/ABWXMLHelper.cpp
@@ -51,7 +51,7 @@ extern "C" {
   static void abwxmlReaderErrorFunc(void *arg, const char *, xmlParserSeverities severity, xmlTextReaderLocatorPtr)
 #endif
   {
-    const auto watcher = reinterpret_cast<ABWXMLErrorWatcher *>(arg);
+    const auto watcher = reinterpret_cast<ABWXMLProgressWatcher *>(arg);
     switch (severity)
     {
     case XML_PARSER_SEVERITY_VALIDITY_WARNING:
@@ -66,7 +66,7 @@ extern "C" {
     case XML_PARSER_SEVERITY_ERROR:
       ABW_DEBUG_MSG(("Found xml parser severity error %s\n", message));
       if (watcher)
-        watcher->setError();
+        watcher->signalError();
       break;
     default:
       break;
@@ -92,29 +92,50 @@ ABWXMLString::operator const char *() const
   return reinterpret_cast<const char *>(m_xml.get());
 }
 
-ABWXMLErrorWatcher::ABWXMLErrorWatcher()
-  : m_error(false)
+ABWXMLProgressWatcher::ABWXMLProgressWatcher()
+  : m_reader(nullptr)
+  , m_line(0)
+  , m_col(0)
+  , m_wasError(false)
+  , m_isStuck(false)
 {
 }
 
-bool ABWXMLErrorWatcher::isError() const
+void ABWXMLProgressWatcher::setReader(xmlTextReaderPtr reader)
 {
-  return m_error;
+  m_reader = reader;
 }
 
-void ABWXMLErrorWatcher::setError()
+bool ABWXMLProgressWatcher::isStuck() const
 {
-  m_error = true;
+  return m_isStuck;
+}
+
+void ABWXMLProgressWatcher::signalError()
+{
+  if (m_reader && !m_isStuck)
+  {
+    const int line = m_line;
+    const int col = m_col;
+    const bool checkStuck = m_wasError;
+    m_wasError = true;
+    m_line = xmlTextReaderGetParserLineNumber(m_reader);
+    m_col = xmlTextReaderGetParserColumnNumber(m_reader);
+    if (checkStuck)
+      m_isStuck = line == m_line && col == m_col;
+  }
 }
 
 // xmlTextReader helper function
 
-std::unique_ptr<xmlTextReader, void(*)(xmlTextReaderPtr)> xmlReaderForStream(librevenge::RVNGInputStream *input, ABWXMLErrorWatcher *watcher)
+std::unique_ptr<xmlTextReader, void(*)(xmlTextReaderPtr)> xmlReaderForStream(librevenge::RVNGInputStream *input, ABWXMLProgressWatcher *watcher)
 {
   std::unique_ptr<xmlTextReader, void(*)(xmlTextReaderPtr)> reader(
     xmlReaderForIO(abwxmlInputReadFunc, abwxmlInputCloseFunc, (void *)input, 0, 0,
                    XML_PARSE_NOBLANKS|XML_PARSE_NOENT|XML_PARSE_NONET|XML_PARSE_RECOVER),
     xmlFreeTextReader);
+  if (watcher)
+    watcher->setReader(reader.get());
   if (reader)
     xmlTextReaderSetErrorHandler(reader.get(), abwxmlReaderErrorFunc, watcher);
   return reader;
diff --git a/src/lib/ABWXMLHelper.h b/src/lib/ABWXMLHelper.h
index 5cd6b2c..b657b19 100644
--- a/src/lib/ABWXMLHelper.h
+++ b/src/lib/ABWXMLHelper.h
@@ -34,23 +34,29 @@ private:
   std::shared_ptr<xmlChar> m_xml;
 };
 
-class ABWXMLErrorWatcher
+class ABWXMLProgressWatcher
 {
-  ABWXMLErrorWatcher(const ABWXMLErrorWatcher &) = delete;
-  ABWXMLErrorWatcher &operator=(const ABWXMLErrorWatcher &) = delete;
+  ABWXMLProgressWatcher(const ABWXMLProgressWatcher &) = delete;
+  ABWXMLProgressWatcher &operator=(const ABWXMLProgressWatcher &) = delete;
 
 public:
-  ABWXMLErrorWatcher();
+  ABWXMLProgressWatcher();
 
-  bool isError() const;
-  void setError();
+  void setReader(xmlTextReaderPtr reader);
+
+  bool isStuck() const;
+  void signalError();
 
 private:
-  bool m_error;
+  xmlTextReaderPtr m_reader;
+  int m_line;
+  int m_col;
+  bool m_wasError;
+  bool m_isStuck;
 };
 
 // create an xmlTextReader pointer from a librevenge::RVNGInputStream pointer
-std::unique_ptr<xmlTextReader, void(*)(xmlTextReaderPtr)> xmlReaderForStream(librevenge::RVNGInputStream *input, ABWXMLErrorWatcher *watcher = 0);
+std::unique_ptr<xmlTextReader, void(*)(xmlTextReaderPtr)> xmlReaderForStream(librevenge::RVNGInputStream *input, ABWXMLProgressWatcher *watcher = 0);
 
 } // namespace libabw