commitctx: extract copy information encoding into extra into commit.py
The encoding of copy information into extra has multiple subcases and become
quite complicated (eg: empty list can be explicitly or implicitly stored for
example). In addition, it is niche experimental feature since as it affect the
hash, it is only suitable for user who don't mercurial for storage server side
(ie: Google).
Having this complexity part of the changelog will get in the way of further
cleanup. We could have to either move more of that logic into the changelog or
to move or extract more of the logic at the higher level. We take the second
approach and start gather logic in dedicated function in commit.py.
# This is a randomized test that generates different pathnames every
# time it is invoked, and tests the encoding of those pathnames.
#
# It uses a simple probabilistic model to generate valid pathnames
# that have proven likely to expose bugs and divergent behavior in
# different encoding implementations.
from __future__ import absolute_import, print_function
import binascii
import collections
import itertools
import math
import os
import random
import sys
import time
from mercurial import (
pycompat,
store,
)
try:
xrange
except NameError:
xrange = range
validchars = set(map(pycompat.bytechr, range(0, 256)))
alphanum = range(ord('A'), ord('Z'))
for c in (b'\0', b'/'):
validchars.remove(c)
winreserved = (
b'aux con prn nul'.split()
+ [b'com%d' % i for i in xrange(1, 10)]
+ [b'lpt%d' % i for i in xrange(1, 10)]
)
def casecombinations(names):
'''Build all case-diddled combinations of names.'''
combos = set()
for r in names:
for i in xrange(len(r) + 1):
for c in itertools.combinations(xrange(len(r)), i):
d = r
for j in c:
d = b''.join((d[:j], d[j : j + 1].upper(), d[j + 1 :]))
combos.add(d)
return sorted(combos)
def buildprobtable(fp, cmd='hg manifest tip'):
'''Construct and print a table of probabilities for path name
components. The numbers are percentages.'''
counts = collections.defaultdict(lambda: 0)
for line in os.popen(cmd).read().splitlines():
if line[-2:] in ('.i', '.d'):
line = line[:-2]
if line.startswith('data/'):
line = line[5:]
for c in line:
counts[c] += 1
for c in '\r/\n':
counts.pop(c, None)
t = sum(pycompat.itervalues(counts)) / 100.0
fp.write('probtable = (')
for i, (k, v) in enumerate(
sorted(counts.items(), key=lambda x: x[1], reverse=True)
):
if (i % 5) == 0:
fp.write('\n ')
vt = v / t
if vt < 0.0005:
break
fp.write('(%r, %.03f), ' % (k, vt))
fp.write('\n )\n')
# A table of character frequencies (as percentages), gleaned by
# looking at filelog names from a real-world, very large repo.
probtable = (
(b't', 9.828),
(b'e', 9.042),
(b's', 8.011),
(b'a', 6.801),
(b'i', 6.618),
(b'g', 5.053),
(b'r', 5.030),
(b'o', 4.887),
(b'p', 4.363),
(b'n', 4.258),
(b'l', 3.830),
(b'h', 3.693),
(b'_', 3.659),
(b'.', 3.377),
(b'm', 3.194),
(b'u', 2.364),
(b'd', 2.296),
(b'c', 2.163),
(b'b', 1.739),
(b'f', 1.625),
(b'6', 0.666),
(b'j', 0.610),
(b'y', 0.554),
(b'x', 0.487),
(b'w', 0.477),
(b'k', 0.476),
(b'v', 0.473),
(b'3', 0.336),
(b'1', 0.335),
(b'2', 0.326),
(b'4', 0.310),
(b'5', 0.305),
(b'9', 0.302),
(b'8', 0.300),
(b'7', 0.299),
(b'q', 0.298),
(b'0', 0.250),
(b'z', 0.223),
(b'-', 0.118),
(b'C', 0.095),
(b'T', 0.087),
(b'F', 0.085),
(b'B', 0.077),
(b'S', 0.076),
(b'P', 0.076),
(b'L', 0.059),
(b'A', 0.058),
(b'N', 0.051),
(b'D', 0.049),
(b'M', 0.046),
(b'E', 0.039),
(b'I', 0.035),
(b'R', 0.035),
(b'G', 0.028),
(b'U', 0.026),
(b'W', 0.025),
(b'O', 0.017),
(b'V', 0.015),
(b'H', 0.013),
(b'Q', 0.011),
(b'J', 0.007),
(b'K', 0.005),
(b'+', 0.004),
(b'X', 0.003),
(b'Y', 0.001),
)
for c, _ in probtable:
validchars.remove(c)
validchars = list(validchars)
def pickfrom(rng, table):
c = 0
r = rng.random() * sum(i[1] for i in table)
for i, p in table:
c += p
if c >= r:
return i
reservedcombos = casecombinations(winreserved)
# The first component of a name following a slash.
firsttable = (
(lambda rng: pickfrom(rng, probtable), 90),
(lambda rng: rng.choice(validchars), 5),
(lambda rng: rng.choice(reservedcombos), 5),
)
# Components of a name following the first.
resttable = firsttable[:-1]
# Special suffixes.
internalsuffixcombos = casecombinations(b'.hg .i .d'.split())
# The last component of a path, before a slash or at the end of a name.
lasttable = resttable + (
(lambda rng: b'', 95),
(lambda rng: rng.choice(internalsuffixcombos), 5),
)
def makepart(rng, k):
'''Construct a part of a pathname, without slashes.'''
p = pickfrom(rng, firsttable)(rng)
l = len(p)
ps = [p]
maxl = rng.randint(1, k)
while l < maxl:
p = pickfrom(rng, resttable)(rng)
l += len(p)
ps.append(p)
ps.append(pickfrom(rng, lasttable)(rng))
return b''.join(ps)
def makepath(rng, j, k):
'''Construct a complete pathname.'''
return (
b'data/'
+ b'/'.join(makepart(rng, k) for _ in xrange(j))
+ rng.choice([b'.d', b'.i'])
)
def genpath(rng, count):
'''Generate random pathnames with gradually increasing lengths.'''
mink, maxk = 1, 4096
def steps():
for i in xrange(count):
yield mink + int(round(math.sqrt((maxk - mink) * float(i) / count)))
for k in steps():
x = rng.randint(1, k)
y = rng.randint(1, k)
yield makepath(rng, x, y)
def runtests(rng, seed, count):
nerrs = 0
for p in genpath(rng, count):
h = store._pathencode(p) # uses C implementation, if available
r = store._hybridencode(p, True) # reference implementation in Python
if h != r:
if nerrs == 0:
print('seed:', hex(seed)[:-1], file=sys.stderr)
print("\np: '%s'" % p.encode("string_escape"), file=sys.stderr)
print("h: '%s'" % h.encode("string_escape"), file=sys.stderr)
print("r: '%s'" % r.encode("string_escape"), file=sys.stderr)
nerrs += 1
return nerrs
def main():
import getopt
# Empirically observed to take about a second to run
count = 100
seed = None
opts, args = getopt.getopt(
sys.argv[1:], 'c:s:', ['build', 'count=', 'seed=']
)
for o, a in opts:
if o in ('-c', '--count'):
count = int(a)
elif o in ('-s', '--seed'):
seed = int(a, base=0) # accepts base 10 or 16 strings
elif o == '--build':
buildprobtable(
sys.stdout,
'find .hg/store/data -type f && '
'cat .hg/store/fncache 2>/dev/null',
)
sys.exit(0)
if seed is None:
try:
seed = int(binascii.hexlify(os.urandom(16)), 16)
except AttributeError:
seed = int(time.time() * 1000)
rng = random.Random(seed)
if runtests(rng, seed, count):
sys.exit(1)
if __name__ == '__main__':
main()