Mercurial > hg
view tests/test-pathencode.py @ 18604:a1141f04e368
manifest: use a size 3 LRU cache to store parsed manifests
Previously, the manifest cache would store the last manifest parsed. We could
run into situations with operations like update where we would try parsing the
manifest for a revision r1, then r2, then r1 again. This increases the cache
size to 3 to avoid that bit of performance fragility.
author | Siddharth Agarwal <sid0@fb.com> |
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date | Sat, 09 Feb 2013 15:43:02 +0000 |
parents | 8c019d2fd7c0 |
children | ff1586a3adc5 9778c77f05d6 |
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# 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 behaviour in # different encoding implementations. from mercurial import parsers from mercurial import store import binascii, itertools, math, os, random, sys, time import collections if sys.version_info[:2] < (2, 6): sys.exit(0) validchars = set(map(chr, range(0, 256))) alphanum = range(ord('A'), ord('Z')) for c in '\0/': validchars.remove(c) winreserved = ('aux con prn nul'.split() + ['com%d' % i for i in xrange(1, 10)] + ['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 = ''.join((d[:j], d[j].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(counts.itervalues()) / 100.0 fp.write('probtable = (') for i, (k, v) in enumerate(sorted(counts.iteritems(), 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 = ( ('t', 9.828), ('e', 9.042), ('s', 8.011), ('a', 6.801), ('i', 6.618), ('g', 5.053), ('r', 5.030), ('o', 4.887), ('p', 4.363), ('n', 4.258), ('l', 3.830), ('h', 3.693), ('_', 3.659), ('.', 3.377), ('m', 3.194), ('u', 2.364), ('d', 2.296), ('c', 2.163), ('b', 1.739), ('f', 1.625), ('6', 0.666), ('j', 0.610), ('y', 0.554), ('x', 0.487), ('w', 0.477), ('k', 0.476), ('v', 0.473), ('3', 0.336), ('1', 0.335), ('2', 0.326), ('4', 0.310), ('5', 0.305), ('9', 0.302), ('8', 0.300), ('7', 0.299), ('q', 0.298), ('0', 0.250), ('z', 0.223), ('-', 0.118), ('C', 0.095), ('T', 0.087), ('F', 0.085), ('B', 0.077), ('S', 0.076), ('P', 0.076), ('L', 0.059), ('A', 0.058), ('N', 0.051), ('D', 0.049), ('M', 0.046), ('E', 0.039), ('I', 0.035), ('R', 0.035), ('G', 0.028), ('U', 0.026), ('W', 0.025), ('O', 0.017), ('V', 0.015), ('H', 0.013), ('Q', 0.011), ('J', 0.007), ('K', 0.005), ('+', 0.004), ('X', 0.003), ('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('.hg .i .d'.split()) # The last component of a path, before a slash or at the end of a name. lasttable = resttable + ( (lambda rng: '', 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] while l <= k: p = pickfrom(rng, resttable)(rng) l += len(p) ps.append(p) ps.append(pickfrom(rng, lasttable)(rng)) return ''.join(ps) def makepath(rng, j, k): '''Construct a complete pathname.''' return ('data/' + '/'.join(makepart(rng, k) for _ in xrange(j)) + rng.choice(['.d', '.i'])) def genpath(rng, count): '''Generate random pathnames with gradually increasing lengths.''' mink, maxk = 1, 4096 def steps(): x, k = 0, mink 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 >> sys.stderr, 'seed:', hex(seed)[:-1] print >> sys.stderr, "\np: '%s'" % p.encode("string_escape") print >> sys.stderr, "h: '%s'" % h.encode("string_escape") print >> sys.stderr, "r: '%s'" % r.encode("string_escape") 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 = long(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 = long(binascii.hexlify(os.urandom(16)), 16) except AttributeError: seed = long(time.time() * 1000) rng = random.Random(seed) if runtests(rng, seed, count): sys.exit(1) if __name__ == '__main__': main()