import struct

import unittest

try:

    from mercurial import rustext

    rustext.__name__  # trigger immediate actual import

except ImportError:

    rustext = None

else:

    from mercurial.rustext import revlog

    # this would fail already without appropriate ancestor.__package__

    from mercurial.rustext.ancestor import LazyAncestors

from mercurial.testing import revlog as revlogtesting

header = struct.unpack(">I", revlogtesting.data_non_inlined[:4])[0]

@unittest.skipIf(

    rustext is None,

    "rustext module revlog relies on is not available",

)

class RustRevlogIndexTest(revlogtesting.RevlogBasedTestBase):

    def test_heads(self):

        idx = self.parseindex()

        rustidx = revlog.MixedIndex(idx, revlogtesting.data_non_inlined, header)

        self.assertEqual(rustidx.headrevs(), idx.headrevs())

    def test_get_cindex(self):

        # drop me once we no longer need the method for shortest node

        idx = self.parseindex()

        rustidx = revlog.MixedIndex(idx, revlogtesting.data_non_inlined, header)

        cidx = rustidx.get_cindex()

        self.assertTrue(idx is cidx)

    def test_len(self):

        idx = self.parseindex()

        rustidx = revlog.MixedIndex(idx, revlogtesting.data_non_inlined, header)

        self.assertEqual(len(rustidx), len(idx))

    def test_ancestors(self):

        idx = self.parseindex()

        rustidx = revlog.MixedIndex(idx, revlogtesting.data_non_inlined, header)

        lazy = LazyAncestors(rustidx, [3], 0, True)

        # we have two more references to the index:

        # - in its inner iterator for __contains__ and __bool__

        # - in the LazyAncestors instance itself (to spawn new iterators)

        self.assertTrue(2 in lazy)

        self.assertTrue(bool(lazy))

        self.assertEqual(list(lazy), [3, 2, 1, 0])

        # a second time to validate that we spawn new iterators

        self.assertEqual(list(lazy), [3, 2, 1, 0])

        # let's check bool for an empty one

if __name__ == '__main__':

    import silenttestrunner

    silenttestrunner.main(__name__)