Avoid leaking memory in case exceptions are thrown while generating FPs

[ptosco]

While running CFFI tests under valgrind I noticed that memory is leaked when an exception is thrown during generation of certain FPs; see the valgrind trace below:

$ valgrind --leak-check=full ./Code/MinimalLib/cffi_test
[...]
==255551==
==255551== HEAP SUMMARY:
==255551==     in use at exit: 192 bytes in 7 blocks
==255551==   total heap usage: 524,741 allocs, 524,734 frees, 39,361,697 bytes allocated
==255551==
==255551== 16 bytes in 1 blocks are definitely lost in loss record 1 of 7
==255551==    at 0x4C2C866: operator new[](unsigned long) (vg_replace_malloc.c:579)
==255551==    by 0x5162D5A: bool boost::vf2_all<boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, RDKit::Atom*, RDKit::Bond*, boost::no_property, boost::listS>, RDKit::detail::AtomLabelFunctor, RDKit::detail::BondL
abelFunctor, RDKit::MolMatchFinalCheckFunctor, std::__cxx11::list<std::__cxx11::list<std::pair<unsigned long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned long> > >, std::allocator<std::__cxx11::list<std::pair<un
signed long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned long> > > > > >(boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, RDKit::Atom*, RDKit::Bond*, boost::no_property, boost::listS> const&,
boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, RDKit::Atom*, RDKit::Bond*, boost::no_property, boost::listS> const&, RDKit::detail::AtomLabelFunctor&, RDKit::detail::BondLabelFunctor&, RDKit::MolMatchFinalCheckF
unctor&, std::__cxx11::list<std::__cxx11::list<std::pair<unsigned long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned long> > >, std::allocator<std::__cxx11::list<std::pair<unsigned long, unsigned long>, std::allo
cator<std::pair<unsigned long, unsigned long> > > > >&, unsigned int) (vf2.hpp:666)
==255551==    by 0x516413A: RDKit::SubstructMatch(RDKit::ROMol const&, RDKit::ROMol const&, RDKit::SubstructMatchParameters const&) (SubstructMatch.cpp:512)
==255551==    by 0x5011D5E: bool RDKit::SubstructMatch<RDKit::ROMol const, RDKit::ROMol>(RDKit::ROMol const&, RDKit::ROMol const&, std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >&, bool, bool, bool) (Substruc
tMatch.h:136)
==255551==    by 0x5381346: (anonymous namespace)::GenerateFP(RDKit::ROMol const&, ExplicitBitVect&) [clone .constprop.0] (MACCS.cpp:600)
==255551==    by 0x5382EBD: RDKit::MACCSFingerprints::getFingerprintAsBitVect(RDKit::ROMol const&) (MACCS.cpp:944)
==255551==    by 0x4FDB3DC: RDKit::MinimalLib::maccs_fp_as_bitvect(RDKit::RWMol const&) (common.h:829)
==255551==    by 0x4FE9A12: get_maccs_fp (cffiwrapper.cpp:636)
==255551==    by 0x111ABA: test_partial_sanitization (cffi_test.c:2157)
==255551==    by 0x10A11E: main (cffi_test.c:2192)
==255551==
==255551== 36 bytes in 1 blocks are definitely lost in loss record 5 of 7
==255551==    at 0x4C2C866: operator new[](unsigned long) (vg_replace_malloc.c:579)
==255551==    by 0x5162D8A: bool boost::vf2_all<boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, RDKit::Atom*, RDKit::Bond*, boost::no_property, boost::listS>, RDKit::detail::AtomLabelFunctor, RDKit::detail::BondL
abelFunctor, RDKit::MolMatchFinalCheckFunctor, std::__cxx11::list<std::__cxx11::list<std::pair<unsigned long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned long> > >, std::allocator<std::__cxx11::list<std::pair<un
signed long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned long> > > > > >(boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, RDKit::Atom*, RDKit::Bond*, boost::no_property, boost::listS> const&,
boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, RDKit::Atom*, RDKit::Bond*, boost::no_property, boost::listS> const&, RDKit::detail::AtomLabelFunctor&, RDKit::detail::BondLabelFunctor&, RDKit::MolMatchFinalCheckF
unctor&, std::__cxx11::list<std::__cxx11::list<std::pair<unsigned long, unsigned long>, std::allocator<std::pair<unsigned long, unsigned long> > >, std::allocator<std::__cxx11::list<std::pair<unsigned long, unsigned long>, std::allo
cator<std::pair<unsigned long, unsigned long> > > > >&, unsigned int) (vf2.hpp:667)
==255551==    by 0x516413A: RDKit::SubstructMatch(RDKit::ROMol const&, RDKit::ROMol const&, RDKit::SubstructMatchParameters const&) (SubstructMatch.cpp:512)
==255551==    by 0x5011D5E: bool RDKit::SubstructMatch<RDKit::ROMol const, RDKit::ROMol>(RDKit::ROMol const&, RDKit::ROMol const&, std::vector<std::pair<int, int>, std::allocator<std::pair<int, int> > >&, bool, bool, bool) (Substruc
tMatch.h:136)
==255551==    by 0x5381346: (anonymous namespace)::GenerateFP(RDKit::ROMol const&, ExplicitBitVect&) [clone .constprop.0] (MACCS.cpp:600)
==255551==    by 0x5382EBD: RDKit::MACCSFingerprints::getFingerprintAsBitVect(RDKit::ROMol const&) (MACCS.cpp:944)
==255551==    by 0x4FDB3DC: RDKit::MinimalLib::maccs_fp_as_bitvect(RDKit::RWMol const&) (common.h:829)
==255551==    by 0x4FE9A12: get_maccs_fp (cffiwrapper.cpp:636)
==255551==    by 0x111ABA: test_partial_sanitization (cffi_test.c:2157)
==255551==    by 0x10A11E: main (cffi_test.c:2192)
==255551==
==255551== 60 (24 direct, 36 indirect) bytes in 1 blocks are definitely lost in loss record 6 of 7
==255551==    at 0x4C2B788: operator new(unsigned long) (vg_replace_malloc.c:417)
==255551==    by 0x5391C66: RDKit::MorganFingerprint::MorganAtomInvGenerator::getAtomInvariants(RDKit::ROMol const&) const (MorganGenerator.cpp:37)
==255551==    by 0x538CA61: RDKit::FingerprintGenerator<unsigned int>::getFingerprintHelper(RDKit::ROMol const&, RDKit::FingerprintFuncArguments&, unsigned long) const (FingerprintGenerator.cpp:161)
==255551==    by 0x538D212: RDKit::FingerprintGenerator<unsigned int>::getFingerprint(RDKit::ROMol const&, RDKit::FingerprintFuncArguments&) const (FingerprintGenerator.cpp:409)
==255551==    by 0x5376671: RDKit::MorganFingerprints::getFingerprintAsBitVect(RDKit::ROMol const&, unsigned int, unsigned int, std::vector<unsigned int, std::allocator<unsigned int> >*, std::vector<unsigned int, std::allocator<unsi
gned int> > const*, bool, bool, bool, std::map<unsigned int, std::vector<std::pair<unsigned int, unsigned int>, std::allocator<std::pair<unsigned int, unsigned int> > >, std::less<unsigned int>, std::allocator<std::pair<unsigned int
 const, std::vector<std::pair<unsigned int, unsigned int>, std::allocator<std::pair<unsigned int, unsigned int> > > > > >*, bool) (MorganFingerprints.cpp:145)
==255551==    by 0x4FF24B1: RDKit::MinimalLib::morgan_fp_as_bitvect(RDKit::RWMol const&, char const*) (common.h:740)
==255551==    by 0x4FF27FA: get_morgan_fp (cffiwrapper.cpp:481)
==255551==    by 0x111A37: test_partial_sanitization (cffi_test.c:2146)
==255551==    by 0x10A11E: main (cffi_test.c:2192)
==255551==
==255551== 80 (24 direct, 56 indirect) bytes in 1 blocks are definitely lost in loss record 7 of 7
==255551==    at 0x4C2B788: operator new(unsigned long) (vg_replace_malloc.c:417)
==255551==    by 0x5382E83: RDKit::MACCSFingerprints::getFingerprintAsBitVect(RDKit::ROMol const&) (MACCS.cpp:943)
==255551==    by 0x4FDB3DC: RDKit::MinimalLib::maccs_fp_as_bitvect(RDKit::RWMol const&) (common.h:829)
==255551==    by 0x4FE9A12: get_maccs_fp (cffiwrapper.cpp:636)
==255551==    by 0x111ABA: test_partial_sanitization (cffi_test.c:2157)
==255551==    by 0x10A11E: main (cffi_test.c:2192)
==255551==
==255551== LEAK SUMMARY:
==255551==    definitely lost: 100 bytes in 4 blocks
==255551==    indirectly lost: 92 bytes in 3 blocks
==255551==      possibly lost: 0 bytes in 0 blocks
==255551==    still reachable: 0 bytes in 0 blocks
==255551==         suppressed: 0 bytes in 0 blocks
==255551==
==255551== For lists of detected and suppressed errors, rerun with: -s
==255551== ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 0 from 0)

This PR avoid all those leaks by wrapping pointer into unique_ptr objects which are only released before returning.

[greglandrum]

LGTM
Thanks!