Hi!
Adding boost smart_ptr library to wesnoth would help a managing
dynamically allocated memory. I have plan to optimize config class with
shared_ptr in 1.5. Shared_ptr adds reference counting to any pointer. It
provides very simple interface to eliminate memory leaks.
Any objections to add it now? I want to use it in server side to make
sure that there is minimal danger for memory leaks so 1.4 server would
be more stable with increasing user numbers.
How to use shared_ptr:
// NOTE: Reset has same effect as code execution going outside pointers
scope. In practice you need rarely call reset. (but we have some palces
where it would be practical)
typedef boost::shared_ptr<config> configPtr;
// Allways use named variable for shared_ptr that holds pointer! if not
using one it has danger of memory leaks because C++ doesn't define code
excecution order allways.
configPtr cfg(new config(...));
if(cfg) // Test if we have valid pointer
{
cfg->add_child(...);
}
// create copy of pointer
configPtr cfg_copy(cfg);
// Now we want to "delete" original pointer
// But because we have 2 pointers to config object
// It isn't destroyed
cfg->reset();
if (!cfg)
{
// cfg not valid pointer so we assign new config object to it
// We also define custom deleter for this. (default uses delete operator)
class deleter {
public:
// operator() is called when object should be destroied
operator ()(config *p) { if (p) destroy_config(p));}
}
cfg = configPtr(new config(...), deleter());
}
// You need raw pointer for SDL? No problem! get method gives raw
pointer but remember to keep shared_ptr object untill raw pointer isn't
needed any more.
SDL_DoFancyStuff(cfg.get());
// now delete copy pointer which destroies config object
cfg_copy->reset();
If you need cyclic pointers between objects you have to se weak_ptr
instead of shared_ptr. weak_ptr is like observer who doesn't own
shared_ptr object :)
There is good documentations in http://www.boost.org/libs/smart_ptr/
Pauli
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