Fix SIGABRT in the searchfiles demo program

[artob]

Attempting to use the supplied bin/searchfiles example program results in the program aborting with SIGABRT:

arto@ubuntu:/src/LucenePlusPlus/bin$ mkdir input output
arto@ubuntu:/src/LucenePlusPlus/bin$ echo 'Hello, world' > input/hello.txt
arto@ubuntu:/src/LucenePlusPlus/bin$ ./indexfiles input output
Indexing to directory: output...
Adding [1]: hello.txt
Index time: 4 milliseconds
Optimizing...
Optimize time: 2 milliseconds
Total time: 6 milliseconds

arto@ubuntu:/src/LucenePlusPlus/bin$ ./searchfiles -index output
Enter query: hello
Searching for: hello
1 total matching documents
1. input/hello.txt
*** glibc detected *** ./searchfiles: free(): invalid pointer: 0x00007fbb260e1b40 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x7eb96)[0x7fbb24a83b96]
./searchfiles[0x405dbe]
./searchfiles[0x4086ee]
./searchfiles[0x40686b]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7fbb24a2676d]
./searchfiles[0x407509]
======= Memory map: ========
...
Aborted

This was built on an Ubuntu 12.10 (x86-64) host with GCC 4.7.2, libstdc++, and Boost 1.50 using cmake . && make && make indexfiles searchfiles deletefiles.

[artob]

Here's the stack trace from running bin/searchfiles -index output in GDB:

Program received signal SIGABRT, Aborted.
0x00007ffff672d425 in raise () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0  0x00007ffff672d425 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007ffff6730b8b in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007ffff676b39e in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#3  0x00007ffff6775b96 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#4  0x0000000000405dbe in deallocate (p=<optimized out>, this=<optimized out>) at /src/LucenePlusPlus/include/LuceneAllocator.h:62
#5  _M_destroy (this=<optimized out>, __a=...) at /usr/include/c++/4.7/bits/basic_string.tcc:451
#6  std::basic_string<wchar_t, std::char_traits<wchar_t>, Lucene::LuceneAllocator<wchar_t> >::_Rep::_M_dispose (this=0x4a78, __a=...)
    at /usr/include/c++/4.7/bits/basic_string.h:246
#7  0x00000000004086ee in _M_dispose (this=<optimized out>, __a=...) at /usr/include/c++/4.7/bits/basic_string.h:237
#8  ~basic_string (this=<optimized out>, __in_chrg=<optimized out>) at /usr/include/c++/4.7/bits/basic_string.h:536
#9  doPagingSearch (searcher=..., query=..., hitsPerPage=hitsPerPage@entry=10, raw=false, interactive=true) at /src/LucenePlusPlus/src/demo/searchfiles/main.cpp:101
#10 0x000000000040686b in main (argc=<optimized out>, argv=<optimized out>) at /src/LucenePlusPlus/src/demo/searchfiles/main.cpp:328

Happy to provide the full memory map output from GDB in case it would be deemed useful.

[artob]

Based on a tip in #24, I was able to work around this problem by editing include/Config.h as follows in order to disable the custom allocator:

#undef LPP_USE_ALLOCATOR

After rebuilding Lucene++ following the aforementioned edit, the bin/searchfiles demo program no longer spuriously crashes, somewhat increasing trust in the robustness of Lucene++ so far as first impressions go.

Perhaps the custom allocator ought to be disabled by default in order to have a better chance of building usable binaries right off the bat?

[alanw]

The custom allocator is only really useful under Windows where allocations across dll boundaries become problematic (ie. allocating and freeing memory from different heaps / runtimes).

It's also useful if you perhaps want to do try funky memory allocators such as nedmalloc, but I understand your point and I think disabling by default is the right way to go.

[artob]

Thanks, Alan!