sax: allow some debug logging in FastParser

Multi-threading makes this difficult; have it print synchronously
where it is in the input when setting:
SAL_LOG="+INFO.sax.fastparser+WARN" SAX_DISABLE_THREADS=1

Change-Id: I8c77974acb2b4d4e273fc9c0f273c345d8feb2ff

include/sal/log-areas.dox

@@ -421,6 +421,7 @@ certain functionality.
 @section sax
 
 @li @c sax.cppunit
+@li @c sax.fastparser
 
 @section stoc
 

sax/README

@@ -8,3 +8,6 @@ UNO services for SAX parsing and C++ functions for XMLSchema-2 data types.
     + C++ wrapper for fast SAX parser
     + C++ XMLSchema-2 data type conversion helpers
 
+Multi-threading in FastParser can be disabled for debugging purposes with:
+SAX_DISABLE_THREADS=1 SAL_LOG="+INFO.sax.fastparser+WARN"
+

sax/source/fastparser/fastparser.cxx

@@ -759,7 +759,8 @@ void FastSaxParserImpl::parseStream(const InputSource& maStructSource)
             rEntity.mxDocumentHandler->startDocument();
         }
 
-        rEntity.mbEnableThreads = (rEntity.maStructSource.aInputStream->available() > 10000);
+        rEntity.mbEnableThreads = rEntity.maStructSource.aInputStream->available() > 10000
+            && !getenv("SAX_DISABLE_THREADS");
 
         if (rEntity.mbEnableThreads)
         {
@@ -1199,7 +1200,10 @@ void FastSaxParserImpl::callbackStartElement(const xmlChar *localName , const xm
         if (rEntity.mbEnableThreads)
             produce();
         else
+        {
+            SAL_INFO("sax.fastparser", " startElement line " << mxDocumentLocator->getLineNumber() << " column " << mxDocumentLocator->getColumnNumber() << " " << prefix << ":" << localName);
             rEntity.startElement( &rEvent );
+        }
     }
     catch (const Exception&)
     {