branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
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)