# 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 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]

    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 ''.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():

        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()