Wrapper for libxml SAX parser C callbacks into C++. More...

#include <SaxParserWrapper.h>

Collaboration diagram for ncml_module::SaxParserWrapper:

Public Member Functions
void	deferException (BESError &theErr)
	The remaining calls are for the internals of the parser, but need to be public. More...

int	getCurrentParseLine () const
	Return the current line of the parse we're on, assuming we're not in an exception state and that we are parsing. More...

SaxParser &	getParser () const

bool	isExceptionState () const
	Used by the callbacks to know whether we have a deferred exception. More...

bool	parse (const string &ncmlFilename)
	Do a SAX parse of the ncmlFilename and pass the calls to wrapper parser. More...

void	rethrowException ()
	If there's a deferred exception, this will throw the right subclass type from the preserved state at deferral time. More...

	SaxParserWrapper (SaxParser &parser)
	Create a wrapper for the given parser. More...

virtual	~SaxParserWrapper ()

Detailed Description

Wrapper for libxml SAX parser C callbacks into C++.

On a parse(const string& ncmlFilename) call, the filename is parsed using the libxml C SAX parser and the C callbacks are passed onto our C++ parser via the SaxParser interface class.

Since the underlying libxml is C and uses its internal static memory pools which will be used by other parts of the BES, we have to be careful with exceptions. Any BESError thrown in a SaxParser callback is caught and deferred (stored in this). We enter an error state and ignore all further callbacks until the libxml parser exits cleanly. Then we recreate and rethrow the deferred exception.

Any other exception types (...) are also caught and a local BESInternalError is thrown at parse end, so be careful with which exceptions are thrown in SaxParser callbacks.

Author: mjohnson m.joh.nosp@m.nson.nosp@m.@open.nosp@m.dap..nosp@m.org

Definition at line 63 of file SaxParserWrapper.h.

Constructor & Destructor Documentation

SaxParserWrapper::SaxParserWrapper ( SaxParser & parser )

Create a wrapper for the given parser.

Parameters

parser Must exist for the duration of the life of the wrapper.

Definition at line 307 of file SaxParserWrapper.cc.

SaxParserWrapper::~SaxParserWrapper ( )

virtual

Definition at line 319 of file SaxParserWrapper.cc.

Member Function Documentation

void SaxParserWrapper::deferException ( BESError & theErr )

The remaining calls are for the internals of the parser, but need to be public.

If we get a BESError exception thrown in a SaxParser call, defer it by entering the EXCEPTION state and copying the exception. In EXCEPTION state, we don't pass on any callbacks to SaxParser. When the underlying C parser completes and cleans up its storage, then we recreate and throw the exception. NOTE: We can't store theErr itself since it will be destroyed by the exception system.