mmgr.cpp

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// ---------------------------------------------------------------------------------------------------------------------------------
// -DOC- When tracking down a difficult bug, use this routine to force a breakpoint on a specific allocation count
// ---------------------------------------------------------------------------------------------------------------------------------

void	m_breakOnAllocation(unsigned int count)
{
	breakOnAllocationCount = count;
}

// ---------------------------------------------------------------------------------------------------------------------------------
// Used by the macros
// ---------------------------------------------------------------------------------------------------------------------------------

void	m_setOwner(const char *file, const unsigned int line, const char *func)
{
	// You're probably wondering about this...
	//
	// It's important for this memory manager to primarily work with global new/delete in their original forms (i.e. with
	// no extra parameters.) In order to do this, we use macros that call this function prior to operators new & delete. This
	// is fine... usually. Here's what actually happens when you use this macro to delete an object:
	//
	// m_setOwner(__FILE__, __LINE__, __FUNCTION__) --> object::~object() --> delete
	//
	// Note that the compiler inserts a call to the object's destructor just prior to calling our overridden operator delete.
	// But what happens when we delete an object whose destructor deletes another object, whose desctuctor deletes another
	// object? Here's a diagram (indentation follows stack depth):
	//
	// m_setOwner(...) -> ~obj1()                          // original call to delete obj1
	//     m_setOwner(...) -> ~obj2()                      // obj1's destructor deletes obj2
	//         m_setOwner(...) -> ~obj3()                  // obj2's destructor deletes obj3
	//             ...                                     // obj3's destructor just does some stuff
	//         delete                                      // back in obj2's destructor, we call delete
	//     delete                                          // back in obj1's destructor, we call delete
	// delete                                              // back to our original call, we call delete
	//
	// Because m_setOwner() just sets up some static variables (below) it's important that each call to m_setOwner() and
	// successive calls to new/delete alternate. However, in this case, three calls to m_setOwner() happen in succession
	// followed by three calls to delete in succession (with a few calls to destructors mixed in for fun.) This means that
	// only the final call to delete (in this chain of events) will have the proper reporting, and the first two in the chain
	// will not have ANY owner-reporting information. The deletes will still work fine, we just won't know who called us.
	//
	// "Then build a stack, my friend!" you might think... but it's a very common thing that people will be working with third-
	// party libraries (including MFC under Windows) which is not compiled with this memory manager's macros. In those cases,
	// m_setOwner() is never called, and rightfully should not have the proper trace-back information. So if one of the
	// destructors in the chain ends up being a call to a delete from a non-mmgr-compiled library, the stack will get confused.
	//
	// I've been unable to find a solution to this problem, but at least we can detect it and report the data before we
	// lose it. That's what this is all about. It makes it somewhat confusing to read in the logs, but at least ALL the
	// information is present...
	//
	// There's a caveat here... The compiler is not required to call operator delete if the value being deleted is NULL.
	// In this case, any call to delete with a NULL will sill call m_setOwner(), which will make m_setOwner() think that
	// there is a destructor chain becuase we setup the variables, but nothing gets called to clear them. Because of this
	// we report a "Possible destructor chain".
	//
	// Thanks to J. Woznack (from Kodiak Interactive Software Studios -- www.kodiakgames.com) for pointing this out.

	if (sourceLine && alwaysLogAll)
	{
		log("[I] NOTE! Possible destructor chain: previous owner is %s", ownerString(sourceFile, sourceLine, sourceFunc));
	}

	// Okay... save this stuff off so we can keep track of the caller

	sourceFile = file;
	sourceLine = line;
	sourceFunc = func;
}

// ---------------------------------------------------------------------------------------------------------------------------------

static	void	resetGlobals()
{
	sourceFile = "??";
	sourceLine = 0;
	sourceFunc = "??";
}

// ---------------------------------------------------------------------------------------------------------------------------------
// Global new/new[]
//
// These are the standard new/new[] operators. They are merely interface functions that operate like normal new/new[], but use our
// memory tracking routines.
// ---------------------------------------------------------------------------------------------------------------------------------

void	*operator new(size_t reportedSize)
{
	#ifdef TEST_MEMORY_MANAGER
	log("[D] ENTER: new");
	#endif

	// Save these off...

	const	char		*file = sourceFile;
	const	unsigned int	line = sourceLine;
	const	char		*func = sourceFunc;

	// ANSI says: allocation requests of 0 bytes will still return a valid value

	if (reportedSize == 0) reportedSize = 1;

	// ANSI says: loop continuously because the error handler could possibly free up some memory

	for(;;)
	{
		// Try the allocation

		void	*ptr = m_allocator(file, line, func, m_alloc_new, reportedSize);
		if (ptr)
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new");
			#endif
			return ptr;
		}

		// There isn't a way to determine the new handler, except through setting it. So we'll just set it to NULL, then
		// set it back again.
		
		std::new_handler	nh = std::set_new_handler(0);
		std::set_new_handler(nh);

		// If there is an error handler, call it

		if (nh)
		{
			(*nh)();
		}

		// Otherwise, throw the exception

		else
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new");
			#endif
			throw std::bad_alloc();
		}
	}
}

// ---------------------------------------------------------------------------------------------------------------------------------

void	*operator new[](size_t reportedSize)
{
	#ifdef TEST_MEMORY_MANAGER
	log("[D] ENTER: new[]");
	#endif

	// Save these off...

	const	char		*file = sourceFile;
	const	unsigned int	line = sourceLine;
	const	char		*func = sourceFunc;

	// The ANSI standard says that allocation requests of 0 bytes will still return a valid value

	if (reportedSize == 0) reportedSize = 1;

	// ANSI says: loop continuously because the error handler could possibly free up some memory

	for(;;)
	{
		// Try the allocation

		void	*ptr = m_allocator(file, line, func, m_alloc_new_array, reportedSize);
		if (ptr)
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new[]");
			#endif
			return ptr;
		}

		// There isn't a way to determine the new handler, except through setting it. So we'll just set it to NULL, then
		// set it back again.

		std::new_handler	nh = std::set_new_handler(0);
		std::set_new_handler(nh);

		// If there is an error handler, call it

		if (nh)
		{
			(*nh)();
		}

		// Otherwise, throw the exception

		else
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new[]");
			#endif
			throw std::bad_alloc();
		}
	}
}

// ---------------------------------------------------------------------------------------------------------------------------------
// Other global new/new[]
//
// These are the standard new/new[] operators as used by Microsoft's memory tracker. We don't want them interfering with our memory
// tracking efforts. Like the previous versions, these are merely interface functions that operate like normal new/new[], but use
// our memory tracking routines.
// ---------------------------------------------------------------------------------------------------------------------------------

void	*operator new(size_t reportedSize, const char *sourceFile, int sourceLine)
{
	#ifdef TEST_MEMORY_MANAGER
	log("[D] ENTER: new");
	#endif

	// The ANSI standard says that allocation requests of 0 bytes will still return a valid value

	if (reportedSize == 0) reportedSize = 1;

	// ANSI says: loop continuously because the error handler could possibly free up some memory

	for(;;)
	{
		// Try the allocation

		void	*ptr = m_allocator(sourceFile, sourceLine, "??", m_alloc_new, reportedSize);
		if (ptr)
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new");
			#endif
			return ptr;
		}

		// There isn't a way to determine the new handler, except through setting it. So we'll just set it to NULL, then
		// set it back again.

		std::new_handler	nh = std::set_new_handler(0);
		std::set_new_handler(nh);

		// If there is an error handler, call it

		if (nh)
		{
			(*nh)();
		}

		// Otherwise, throw the exception

		else
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new");
			#endif
			throw std::bad_alloc();
		}
	}
}

// ---------------------------------------------------------------------------------------------------------------------------------

void	*operator new[](size_t reportedSize, const char *sourceFile, int sourceLine)
{
	#ifdef TEST_MEMORY_MANAGER
	log("[D] ENTER: new[]");
	#endif

	// The ANSI standard says that allocation requests of 0 bytes will still return a valid value

	if (reportedSize == 0) reportedSize = 1;

	// ANSI says: loop continuously because the error handler could possibly free up some memory

	for(;;)
	{
		// Try the allocation

		void	*ptr = m_allocator(sourceFile, sourceLine, "??", m_alloc_new_array, reportedSize);
		if (ptr)
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new[]");
			#endif
			return ptr;
		}

		// There isn't a way to determine the new handler, except through setting it. So we'll just set it to NULL, then
		// set it back again.

		std::new_handler	nh = std::set_new_handler(0);
		std::set_new_handler(nh);

		// If there is an error handler, call it

		if (nh)
		{
			(*nh)();
		}

		// Otherwise, throw the exception

		else
		{
			#ifdef TEST_MEMORY_MANAGER
			log("[D] EXIT : new[]");
			#endif
			throw std::bad_alloc();
		}
	}
}

// ---------------------------------------------------------------------------------------------------------------------------------
// Global delete/delete[]
//
// These are the standard delete/delete[] operators. They are merely interface functions that operate like normal delete/delete[],
// but use our memory tracking routines.
// ---------------------------------------------------------------------------------------------------------------------------------

void	operator delete(void *reportedAddress)
{
	#ifdef TEST_MEMORY_MANAGER
	log("[D] ENTER: delete");
	#endif

	// ANSI says: delete & delete[] allow NULL pointers (they do nothing)

	if (reportedAddress) m_deallocator(sourceFile, sourceLine, sourceFunc, m_alloc_delete, reportedAddress);
	else if (alwaysLogAll) log("[-] ----- %8s of NULL                      by %s", allocationTypes[m_alloc_delete], ownerString(sourceFile, sourceLine, sourceFunc));

	// Resetting the globals insures that if at some later time, somebody calls our memory manager from an unknown
	// source (i.e. they didn't include our H file) then we won't think it was the last allocation.

	resetGlobals();

	#ifdef TEST_MEMORY_MANAGER