view tests/test-bdiff.py @ 39859:32d3ed3023bb

upgrade: use rawsize() instead of revlog index

The revlog index is a very low-level data structure and it shouldn't
be exposed to the storage interface - at least not in its current
form.

upgrade.py is the only consumer of the index attribute on file storage
in the repository.

This commit rewrites that final consumer to use rawsize() instead of
going through the index. This is actually the more proper API to use,
as rawsize() will accurately report the size of revisions which have
a negative size in the index.

Differential Revision: https://phab.mercurial-scm.org/D4719

from __future__ import absolute_import, print_function
import collections
import struct
import unittest

from mercurial import (
    mdiff,
)

class diffreplace(
    collections.namedtuple('diffreplace', 'start end from_ to')):
    def __repr__(self):
        return 'diffreplace(%r, %r, %r, %r)' % self

class BdiffTests(unittest.TestCase):

    def assert_bdiff_applies(self, a, b):
        d = mdiff.textdiff(a, b)
        c = a
        if d:
            c = mdiff.patches(a, [d])
        self.assertEqual(
            c, b, ("bad diff+patch result from\n  %r to\n  "
                   "%r: \nbdiff: %r\npatched: %r" % (a, b, d, c[:200])))

    def assert_bdiff(self, a, b):
        self.assert_bdiff_applies(a, b)
        self.assert_bdiff_applies(b, a)

    def test_bdiff_basic(self):
        cases = [
            (b"a\nc\n\n\n\n", b"a\nb\n\n\n"),
            (b"a\nb\nc\n", b"a\nc\n"),
            (b"", b""),
            (b"a\nb\nc", b"a\nb\nc"),
            (b"a\nb\nc\nd\n", b"a\nd\n"),
            (b"a\nb\nc\nd\n", b"a\nc\ne\n"),
            (b"a\nb\nc\n", b"a\nc\n"),
            (b"a\n", b"c\na\nb\n"),
            (b"a\n", b""),
            (b"a\n", b"b\nc\n"),
            (b"a\n", b"c\na\n"),
            (b"", b"adjfkjdjksdhfksj"),
            (b"", b"ab"),
            (b"", b"abc"),
            (b"a", b"a"),
            (b"ab", b"ab"),
            (b"abc", b"abc"),
            (b"a\n", b"a\n"),
            (b"a\nb", b"a\nb"),
        ]
        for a, b in cases:
            self.assert_bdiff(a, b)

    def showdiff(self, a, b):
        bin = mdiff.textdiff(a, b)
        pos = 0
        q = 0
        actions = []
        while pos < len(bin):
            p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
            pos += 12
            if p1:
                actions.append(a[q:p1])
            actions.append(diffreplace(p1, p2, a[p1:p2], bin[pos:pos + l]))
            pos += l
            q = p2
        if q < len(a):
            actions.append(a[q:])
        return actions

    def test_issue1295(self):
        cases = [
            (b"x\n\nx\n\nx\n\nx\n\nz\n", b"x\n\nx\n\ny\n\nx\n\nx\n\nz\n",
             [b'x\n\nx\n\n',
              diffreplace(6, 6, b'', b'y\n\n'),
              b'x\n\nx\n\nz\n']),
            (b"x\n\nx\n\nx\n\nx\n\nz\n", b"x\n\nx\n\ny\n\nx\n\ny\n\nx\n\nz\n",
             [b'x\n\nx\n\n',
              diffreplace(6, 6, b'', b'y\n\n'),
              b'x\n\n',
              diffreplace(9, 9, b'', b'y\n\n'),
              b'x\n\nz\n']),
        ]
        for old, new, want in cases:
            self.assertEqual(self.showdiff(old, new), want)

    def test_issue1295_varies_on_pure(self):
            # we should pick up abbbc. rather than bc.de as the longest match
        got = self.showdiff(b"a\nb\nb\nb\nc\n.\nd\ne\n.\nf\n",
                            b"a\nb\nb\na\nb\nb\nb\nc\n.\nb\nc\n.\nd\ne\nf\n")
        want_c = [b'a\nb\nb\n',
                  diffreplace(6, 6, b'', b'a\nb\nb\nb\nc\n.\n'),
                  b'b\nc\n.\nd\ne\n',
                  diffreplace(16, 18, b'.\n', b''),
                  b'f\n']
        want_pure = [diffreplace(0, 0, b'', b'a\nb\nb\n'),
                     b'a\nb\nb\nb\nc\n.\n',
                     diffreplace(12, 12, b'', b'b\nc\n.\n'),
                     b'd\ne\n',
                     diffreplace(16, 18, b'.\n', b''), b'f\n']
        self.assertTrue(got in (want_c, want_pure),
                        'got: %r, wanted either %r or %r' % (
                            got, want_c, want_pure))

    def test_fixws(self):
        cases = [
            (b" \ta\r b\t\n", b"ab\n", 1),
            (b" \ta\r b\t\n", b" a b\n", 0),
            (b"", b"", 1),
            (b"", b"", 0),
        ]
        for a, b, allws in cases:
            c = mdiff.fixws(a, allws)
            self.assertEqual(
                c, b, 'fixws(%r) want %r got %r (allws=%r)' % (a, b, c, allws))

    def test_nice_diff_for_trivial_change(self):
        self.assertEqual(self.showdiff(
            b''.join(b'<%d\n-\n' % i for i in range(5)),
            b''.join(b'>%d\n-\n' % i for i in range(5))),
                         [diffreplace(0, 3, b'<0\n', b'>0\n'),
                          b'-\n',
                          diffreplace(5, 8, b'<1\n', b'>1\n'),
                          b'-\n',
                          diffreplace(10, 13, b'<2\n', b'>2\n'),
                          b'-\n',
                          diffreplace(15, 18, b'<3\n', b'>3\n'),
                          b'-\n',
                          diffreplace(20, 23, b'<4\n', b'>4\n'),
                          b'-\n'])

    def test_prefer_appending(self):
        # 1 line to 3 lines
        self.assertEqual(self.showdiff(b'a\n', b'a\n' * 3),
                         [b'a\n', diffreplace(2, 2, b'', b'a\na\n')])
        # 1 line to 5 lines
        self.assertEqual(self.showdiff(b'a\n', b'a\n' * 5),
                         [b'a\n', diffreplace(2, 2, b'', b'a\na\na\na\n')])

    def test_prefer_removing_trailing(self):
        # 3 lines to 1 line
        self.assertEqual(self.showdiff(b'a\n' * 3, b'a\n'),
                         [b'a\n', diffreplace(2, 6, b'a\na\n', b'')])
        # 5 lines to 1 line
        self.assertEqual(self.showdiff(b'a\n' * 5, b'a\n'),
                         [b'a\n', diffreplace(2, 10, b'a\na\na\na\n', b'')])

if __name__ == '__main__':
    import silenttestrunner
    silenttestrunner.main(__name__)