comparison mercurial/parsers.c @ 24736:f2fd087a75ef

parsers: when available, use a presized dictionary for the file foldmap

On a repo with over 300,000 files, this speeds up perffilefoldmap:

before: wall 0.178421 comb 0.180000 user 0.160000 sys 0.020000 (best of 55)
after:  wall 0.164462 comb 0.160000 user 0.140000 sys 0.020000 (best of 59)

24735:07200e3332a1

	default:
		PyErr_SetString(PyExc_TypeError, "invalid normcasespec");
		goto quit;
	}

	file_foldmap = PyDict_New();
	if (file_foldmap == NULL)
		goto quit;

	while (PyDict_Next(dmap, &pos, &k, &v)) {
		if (!dirstate_tuple_check(v)) {

24736:f2fd087a75ef

	default:
		PyErr_SetString(PyExc_TypeError, "invalid normcasespec");
		goto quit;
	}

#if PY_VERSION_HEX >= 0x02060000
	/* _PyDict_NewPresized expects a minused parameter, but it actually
	   creates a dictionary that's the nearest power of two bigger than the
	   parameter. For example, with the initial minused = 1000, the
	   dictionary created has size 1024. Of course in a lot of cases that
	   can be greater than the maximum load factor Python's dict object
	   expects (= 2/3), so as soon as we cross the threshold we'll resize
	   anyway. So create a dictionary that's 3/2 the size. Also add some
	   more to deal with additions outside this function. */
	file_foldmap = _PyDict_NewPresized((PyDict_Size(dmap) / 5) * 8);
#else
	file_foldmap = PyDict_New();
#endif

	if (file_foldmap == NULL)
		goto quit;

	while (PyDict_Next(dmap, &pos, &k, &v)) {
		if (!dirstate_tuple_check(v)) {