branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
import itertools
from mercurial import pycompat
from hgext import absorb
class simplefctx:
def __init__(self, content):
self.content = content
def data(self):
return self.content
def insertreturns(x):
# insert "\n"s after each single char
if isinstance(x, bytes):
return b''.join(ch + b'\n' for ch in pycompat.bytestr(x))
else:
return pycompat.maplist(insertreturns, x)
def removereturns(x):
# the revert of "insertreturns"
if isinstance(x, bytes):
return x.replace(b'\n', b'')
else:
return pycompat.maplist(removereturns, x)
def assertlistequal(lhs, rhs, decorator=lambda x: x):
if lhs != rhs:
raise RuntimeError(
'mismatch:\n actual: %r\n expected: %r'
% tuple(map(decorator, [lhs, rhs]))
)
def testfilefixup(oldcontents, workingcopy, expectedcontents, fixups=None):
"""([str], str, [str], [(rev, a1, a2, b1, b2)]?) -> None
workingcopy is a string, of which every character denotes a single line.
oldcontents, expectedcontents are lists of strings, every character of
every string denots a single line.
if fixups is not None, it's the expected fixups list and will be checked.
"""
expectedcontents = insertreturns(expectedcontents)
oldcontents = insertreturns(oldcontents)
workingcopy = insertreturns(workingcopy)
state = absorb.filefixupstate(
pycompat.maplist(simplefctx, oldcontents), 'path'
)
state.diffwith(simplefctx(workingcopy))
if fixups is not None:
assertlistequal(state.fixups, fixups)
state.apply()
assertlistequal(state.finalcontents, expectedcontents, removereturns)
def buildcontents(linesrevs):
# linesrevs: [(linecontent : str, revs : [int])]
revs = set(itertools.chain(*[revs for line, revs in linesrevs]))
return [b''] + [
b''.join([l for l, rs in linesrevs if r in rs]) for r in sorted(revs)
]
# input case 0: one single commit
case0 = [b'', b'11']
# replace a single chunk
testfilefixup(case0, b'', [b'', b''])
testfilefixup(case0, b'2', [b'', b'2'])
testfilefixup(case0, b'22', [b'', b'22'])
testfilefixup(case0, b'222', [b'', b'222'])
# input case 1: 3 lines, each commit adds one line
case1 = buildcontents(
[
(b'1', [1, 2, 3]),
(b'2', [2, 3]),
(b'3', [3]),
]
)
# 1:1 line mapping
testfilefixup(case1, b'123', case1)
testfilefixup(case1, b'12c', [b'', b'1', b'12', b'12c'])
testfilefixup(case1, b'1b3', [b'', b'1', b'1b', b'1b3'])
testfilefixup(case1, b'1bc', [b'', b'1', b'1b', b'1bc'])
testfilefixup(case1, b'a23', [b'', b'a', b'a2', b'a23'])
testfilefixup(case1, b'a2c', [b'', b'a', b'a2', b'a2c'])
testfilefixup(case1, b'ab3', [b'', b'a', b'ab', b'ab3'])
testfilefixup(case1, b'abc', [b'', b'a', b'ab', b'abc'])
# non 1:1 edits
testfilefixup(case1, b'abcd', case1)
testfilefixup(case1, b'ab', case1)
# deletion
testfilefixup(case1, b'', [b'', b'', b'', b''])
testfilefixup(case1, b'1', [b'', b'1', b'1', b'1'])
testfilefixup(case1, b'2', [b'', b'', b'2', b'2'])
testfilefixup(case1, b'3', [b'', b'', b'', b'3'])
testfilefixup(case1, b'13', [b'', b'1', b'1', b'13'])
# replaces
testfilefixup(case1, b'1bb3', [b'', b'1', b'1bb', b'1bb3'])
# (confusing) replaces
testfilefixup(case1, b'1bbb', case1)
testfilefixup(case1, b'bbbb', case1)
testfilefixup(case1, b'bbb3', case1)
testfilefixup(case1, b'1b', case1)
testfilefixup(case1, b'bb', case1)
testfilefixup(case1, b'b3', case1)
# insertions at the beginning and the end
testfilefixup(case1, b'123c', [b'', b'1', b'12', b'123c'])
testfilefixup(case1, b'a123', [b'', b'a1', b'a12', b'a123'])
# (confusing) insertions
testfilefixup(case1, b'1a23', case1)
testfilefixup(case1, b'12b3', case1)
# input case 2: delete in the middle
case2 = buildcontents(
[
(b'11', [1, 2]),
(b'22', [1]),
(b'33', [1, 2]),
]
)
# deletion (optimize code should make it 2 chunks)
testfilefixup(
case2, b'', [b'', b'22', b''], fixups=[(4, 0, 2, 0, 0), (4, 2, 4, 0, 0)]
)
# 1:1 line mapping
testfilefixup(case2, b'aaaa', [b'', b'aa22aa', b'aaaa'])
# non 1:1 edits
# note: unlike case0, the chunk is not "continuous" and no edit allowed
testfilefixup(case2, b'aaa', case2)
# input case 3: rev 3 reverts rev 2
case3 = buildcontents(
[
(b'1', [1, 2, 3]),
(b'2', [2]),
(b'3', [1, 2, 3]),
]
)
# 1:1 line mapping
testfilefixup(case3, b'13', case3)
testfilefixup(case3, b'1b', [b'', b'1b', b'12b', b'1b'])
testfilefixup(case3, b'a3', [b'', b'a3', b'a23', b'a3'])
testfilefixup(case3, b'ab', [b'', b'ab', b'a2b', b'ab'])
# non 1:1 edits
testfilefixup(case3, b'a', case3)
testfilefixup(case3, b'abc', case3)
# deletion
testfilefixup(case3, b'', [b'', b'', b'2', b''])
# insertion
testfilefixup(case3, b'a13c', [b'', b'a13c', b'a123c', b'a13c'])
# input case 4: a slightly complex case
case4 = buildcontents(
[
(b'1', [1, 2, 3]),
(b'2', [2, 3]),
(
b'3',
[
1,
2,
],
),
(b'4', [1, 3]),
(b'5', [3]),
(b'6', [2, 3]),
(b'7', [2]),
(b'8', [2, 3]),
(b'9', [3]),
]
)
testfilefixup(case4, b'1245689', case4)
testfilefixup(case4, b'1a2456bbb', case4)
testfilefixup(case4, b'1abc5689', case4)
testfilefixup(case4, b'1ab5689', [b'', b'134', b'1a3678', b'1ab5689'])
testfilefixup(case4, b'aa2bcd8ee', [b'', b'aa34', b'aa23d78', b'aa2bcd8ee'])
testfilefixup(case4, b'aa2bcdd8ee', [b'', b'aa34', b'aa23678', b'aa24568ee'])
testfilefixup(case4, b'aaaaaa', case4)
testfilefixup(case4, b'aa258b', [b'', b'aa34', b'aa2378', b'aa258b'])
testfilefixup(case4, b'25bb', [b'', b'34', b'23678', b'25689'])
testfilefixup(case4, b'27', [b'', b'34', b'23678', b'245689'])
testfilefixup(case4, b'28', [b'', b'34', b'2378', b'28'])
testfilefixup(case4, b'', [b'', b'34', b'37', b''])
# input case 5: replace a small chunk which is near a deleted line
case5 = buildcontents(
[
(b'12', [1, 2]),
(b'3', [1]),
(b'4', [1, 2]),
]
)
testfilefixup(case5, b'1cd4', [b'', b'1cd34', b'1cd4'])
# input case 6: base "changeset" is immutable
case6 = [b'1357', b'0125678']
testfilefixup(case6, b'0125678', case6)
testfilefixup(case6, b'0a25678', case6)
testfilefixup(case6, b'0a256b8', case6)
testfilefixup(case6, b'abcdefg', [b'1357', b'a1c5e7g'])
testfilefixup(case6, b'abcdef', case6)
testfilefixup(case6, b'', [b'1357', b'157'])
testfilefixup(case6, b'0123456789', [b'1357', b'0123456789'])
# input case 7: change an empty file
case7 = [b'']
testfilefixup(case7, b'1', case7)