Minor memory leaks in gmlreader.cpp

Mateusz,

I'd like you to review these changes and apply them if they seem appropriate.

Note, please ensure that the XMLPlatformUtils::Terminate() does not interfere with other GMLReader's that may be active at the same time. So try tests where two GML datastores are open at the same time. Close one, and then verify you can still read from the other.

I suspect the patch will have to be changed to keep track of how many GMLReader's are active, and only call the Terminate() when the last one is destroyed. Presumably that logic should also set m_bXercesInitialized to FALSE.

Since this is low priority and a bit risky as a change, I'd like to hold it to trunk, not the stable branch.

This is regular patch including fixes proposed in attached big gmlreaderp.h and gmlreader.cpp files. This patch is to help to review proposed changes.

This is new improved version of proposed patch. The original version is buggy, because it's forbidden to use std::auto_ptr with buffers allocated by memory manager used in XMLString due to delete / delete[] mismatch.

Simple test presenting the proposed patch in action. Running this test result in segmentation fault because internal state of the reader is broken. As Frank predicted, the solution is to track number of XML readers. This test uses road.gml copied to road1.gml and road2.gml. Attached Makefile is used to compile the test.

Makefile used to build test.cpp program

Sample GML file. Second copy 'road2.gml' is needed by the test.cpp program.

It's important to note that only first run of ./test program throws segmentation fault. Next, .gfs files are available and further executions do not crash.