[PATCH 1 of 7 V4] sparse-revlog: add a `index_get_start` function in C

[Boris FELD]

On 21/11/2018 13:30, Yuya Nishihara wrote:
> On Tue, 20 Nov 2018 21:44:32 +0100, Boris Feld wrote:
>> # HG changeset patch
>> # User Boris Feld <boris.feld at octobus.net>
>> # Date 1542725358 0
>> #      Tue Nov 20 14:49:18 2018 +0000
>> # Node ID 60a55da39befa4996c1a88ca6f663765ea143ef2
>> # Parent  337a389953366f059f2cb88129031ba3e67e0bbc
>> # EXP-Topic sparse-perf
>> # Available At https://bitbucket.org/octobus/mercurial-devel/
>> #              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 60a55da39bef
>> sparse-revlog: add a `index_get_start` function in C
>> diff --git a/mercurial/cext/revlog.c b/mercurial/cext/revlog.c
>> --- a/mercurial/cext/revlog.c
>> +++ b/mercurial/cext/revlog.c
>> @@ -185,6 +185,46 @@ static inline int index_get_parents(inde
>>  	return 0;
>>  }
>>  
>> +static inline int64_t index_get_start(indexObject *self, Py_ssize_t rev)
> I meant "int index_get_start(*self, rev, *offset)" just like index_get_parents(),
> but this is also good.
Since the return is simpler than index_get_parent, it seemed simpler to
return the value directly.
>
>> +{
>> +	uint64_t offset;
>> +	if (rev >= self->length) {
>> +		PyObject *tuple;
>> +		PyObject *pylong;
>> +		unsigned PY_LONG_LONG tmp;
>> +		tuple = PyList_GET_ITEM(self->added, rev - self->length);
>> +		pylong = PyTuple_GET_ITEM(tuple, 0);
>> +#ifndef IS_PY3K
>> +		if (PyInt_Check(pylong)) {
>> +			long tmp2 = PyInt_AsLong(pylong);
>> +			if (tmp2 < 0) {
>> +				return -1;
>> +			}
>> +			tmp = (unsigned PY_LONG_LONG)tmp2;
>> +		} else {
>> +#endif
>> +			tmp = PyLong_AsUnsignedLongLong(pylong);
>> +			if (tmp == (unsigned PY_LONG_LONG) - 1) {
>> +				return -1;
>> +			}
>> +
>> +#ifndef IS_PY3K
>> +		}
>> +#endif
>> +		offset = (uint64_t)tmp;
> Sigh, PyLong API is so inconsistent on Python 2. Let's switch to
> PyLong_AsLongLong(), which can handle PyInt as well. I think it's
> okay to raise OverflowError if offset >= 1 << (63 - 16).

Okay, so dropping the special case and directly using:

  offset = PyLong_AsLongLong(pylong);
  if (offset < 0){ … }

Right?
>
> FWIW, PyLong_AsUnsignedLongLong() of Python 2 would raise BadInternalCall
> if non-long type were passed.
Yep, I saw that, and it's how I ended up adding the PyInt case.
> _______________________________________________
> Mercurial-devel mailing list
> Mercurial-devel at mercurial-scm.org
> https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel