revlog: have an explicit "pack_header" method
Having to pass the version header when retrieving the binary version of every
single entry is a bit silly. So we extract that special logic in its own method.
This also prepare the move to newer revlog format, not storing the header within
an actual entry…
Differential Revision: https://phab.mercurial-scm.org/D10510
# 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()