view tests/test-manifest.py @ 30442:41a8106789ca

util: implement zstd compression engine

Now that zstd is vendored and being built (in some configurations), we
can implement a compression engine for zstd!

The zstd engine is a little different from existing engines. Because
it may not always be present, we have to defer load the module in case
importing it fails. We facilitate this via a cached property that holds
a reference to the module or None. The "available" method is
implemented to reflect reality.

The zstd engine declares its ability to handle bundles using the
"zstd" human name and the "ZS" internal name. The latter was chosen
because internal names are 2 characters (by only convention I think)
and "ZS" seems reasonable.

The engine, like others, supports specifying the compression level.
However, there are no consumers of this API that yet pass in that
argument. I have plans to change that, so stay tuned.

Since all we need to do to support bundle generation with a new
compression engine is implement and register the compression engine,
bundle generation with zstd "just works!" Tests demonstrating this
have been added.

How does performance of zstd for bundle generation compare? On the
mozilla-unified repo, `hg bundle --all -t <engine>-v2` yields the
following on my i7-6700K on Linux:

engine        CPU time     bundle size   vs orig size   throughput
none            97.0s     4,054,405,584     100.0%       41.8 MB/s
bzip2 (l=9)    393.6s       975,343,098      24.0%       10.3 MB/s
gzip (l=6)     184.0s     1,140,533,074      28.1%       22.0 MB/s
zstd (l=1)     108.2s     1,119,434,718      27.6%       37.5 MB/s
zstd (l=2)     111.3s     1,078,328,002      26.6%       36.4 MB/s
zstd (l=3)     113.7s     1,011,823,727      25.0%       35.7 MB/s
zstd (l=4)     116.0s     1,008,965,888      24.9%       35.0 MB/s
zstd (l=5)     121.0s       977,203,148      24.1%       33.5 MB/s
zstd (l=6)     131.7s       927,360,198      22.9%       30.8 MB/s
zstd (l=7)     139.0s       912,808,505      22.5%       29.2 MB/s
zstd (l=12)    198.1s       854,527,714      21.1%       20.5 MB/s
zstd (l=18)    681.6s       789,750,690      19.5%        5.9 MB/s

On compression, zstd for bundle generation delivers:

* better compression than gzip with significantly less CPU utilization
* better than bzip2 compression ratios while still being significantly
  faster than gzip
* ability to aggressively tune compression level to achieve
  significantly smaller bundles

That last point is important. With clone bundles, a server can
pre-generate a bundle file, upload it to a static file server, and
redirect clients to transparently download it during clone. The server
could choose to produce a zstd bundle with the highest compression
settings possible. This would take a very long time - a magnitude
longer than a typical zstd bundle generation - but the result would
be hundreds of megabytes smaller! For the clone volume we do at
Mozilla, this could translate to petabytes of bandwidth savings
per year and faster clones (due to smaller transfer size).

I don't have detailed numbers to report on decompression. However,
zstd decompression is fast: >1 GB/s output throughput on this machine,
even through the Python bindings. And it can do that regardless of the
compression level of the input. By the time you have enough data to
worry about overhead of decompression, you have plenty of other things
to worry about performance wise.

zstd is wins all around. I can't wait to implement support for it
on the wire protocol and in revlogs.

from __future__ import absolute_import

import binascii
import itertools
import silenttestrunner
import unittest

from mercurial import (
    manifest as manifestmod,
    match as matchmod,
)

EMTPY_MANIFEST = ''
EMTPY_MANIFEST_V2 = '\0\n'

HASH_1 = '1' * 40
BIN_HASH_1 = binascii.unhexlify(HASH_1)
HASH_2 = 'f' * 40
BIN_HASH_2 = binascii.unhexlify(HASH_2)
HASH_3 = '1234567890abcdef0987654321deadbeef0fcafe'
BIN_HASH_3 = binascii.unhexlify(HASH_3)
A_SHORT_MANIFEST = (
    'bar/baz/qux.py\0%(hash2)s%(flag2)s\n'
    'foo\0%(hash1)s%(flag1)s\n'
    ) % {'hash1': HASH_1,
         'flag1': '',
         'hash2': HASH_2,
         'flag2': 'l',
         }

# Same data as A_SHORT_MANIFEST
A_SHORT_MANIFEST_V2 = (
    '\0\n'
    '\x00bar/baz/qux.py\0%(flag2)s\n%(hash2)s\n'
    '\x00foo\0%(flag1)s\n%(hash1)s\n'
    ) % {'hash1': BIN_HASH_1,
         'flag1': '',
         'hash2': BIN_HASH_2,
         'flag2': 'l',
         }

# Same data as A_SHORT_MANIFEST
A_METADATA_MANIFEST = (
    '\0foo\0bar\n'
    '\x00bar/baz/qux.py\0%(flag2)s\0foo\0bar\n%(hash2)s\n' # flag and metadata
    '\x00foo\0%(flag1)s\0foo\n%(hash1)s\n' # no flag, but metadata
    ) % {'hash1': BIN_HASH_1,
         'flag1': '',
         'hash2': BIN_HASH_2,
         'flag2': 'l',
         }

A_STEM_COMPRESSED_MANIFEST = (
    '\0\n'
    '\x00bar/baz/qux.py\0%(flag2)s\n%(hash2)s\n'
    '\x04qux/foo.py\0%(flag1)s\n%(hash1)s\n' # simple case of 4 stem chars
    '\x0az.py\0%(flag1)s\n%(hash1)s\n' # tricky newline = 10 stem characters
    '\x00%(verylongdir)sx/x\0\n%(hash1)s\n'
    '\xffx/y\0\n%(hash2)s\n' # more than 255 stem chars
    ) % {'hash1': BIN_HASH_1,
         'flag1': '',
         'hash2': BIN_HASH_2,
         'flag2': 'l',
         'verylongdir': 255 * 'x',
         }

A_DEEPER_MANIFEST = (
    'a/b/c/bar.py\0%(hash3)s%(flag1)s\n'
    'a/b/c/bar.txt\0%(hash1)s%(flag1)s\n'
    'a/b/c/foo.py\0%(hash3)s%(flag1)s\n'
    'a/b/c/foo.txt\0%(hash2)s%(flag2)s\n'
    'a/b/d/baz.py\0%(hash3)s%(flag1)s\n'
    'a/b/d/qux.py\0%(hash1)s%(flag2)s\n'
    'a/b/d/ten.txt\0%(hash3)s%(flag2)s\n'
    'a/b/dog.py\0%(hash3)s%(flag1)s\n'
    'a/b/fish.py\0%(hash2)s%(flag1)s\n'
    'a/c/london.py\0%(hash3)s%(flag2)s\n'
    'a/c/paper.txt\0%(hash2)s%(flag2)s\n'
    'a/c/paris.py\0%(hash2)s%(flag1)s\n'
    'a/d/apple.py\0%(hash3)s%(flag1)s\n'
    'a/d/pizza.py\0%(hash3)s%(flag2)s\n'
    'a/green.py\0%(hash1)s%(flag2)s\n'
    'a/purple.py\0%(hash2)s%(flag1)s\n'
    'app.py\0%(hash3)s%(flag1)s\n'
    'readme.txt\0%(hash2)s%(flag1)s\n'
    ) % {'hash1': HASH_1,
         'flag1': '',
         'hash2': HASH_2,
         'flag2': 'l',
         'hash3': HASH_3,
         }

HUGE_MANIFEST_ENTRIES = 200001

A_HUGE_MANIFEST = ''.join(sorted(
    'file%d\0%s%s\n' % (i, h, f) for i, h, f in
    itertools.izip(xrange(200001),
                   itertools.cycle((HASH_1, HASH_2)),
                   itertools.cycle(('', 'x', 'l')))))

class basemanifesttests(object):
    def parsemanifest(self, text):
        raise NotImplementedError('parsemanifest not implemented by test case')

    def assertIn(self, thing, container, msg=None):
        # assertIn new in 2.7, use it if available, otherwise polyfill
        sup = getattr(unittest.TestCase, 'assertIn', False)
        if sup:
            return sup(self, thing, container, msg=msg)
        if not msg:
            msg = 'Expected %r in %r' % (thing, container)
        self.assert_(thing in container, msg)

    def testEmptyManifest(self):
        m = self.parsemanifest(EMTPY_MANIFEST)
        self.assertEqual(0, len(m))
        self.assertEqual([], list(m))

    def testEmptyManifestv2(self):
        m = self.parsemanifest(EMTPY_MANIFEST_V2)
        self.assertEqual(0, len(m))
        self.assertEqual([], list(m))

    def testManifest(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        self.assertEqual(['bar/baz/qux.py', 'foo'], list(m))
        self.assertEqual(BIN_HASH_2, m['bar/baz/qux.py'])
        self.assertEqual('l', m.flags('bar/baz/qux.py'))
        self.assertEqual(BIN_HASH_1, m['foo'])
        self.assertEqual('', m.flags('foo'))
        self.assertRaises(KeyError, lambda : m['wat'])

    def testParseManifestV2(self):
        m1 = self.parsemanifest(A_SHORT_MANIFEST)
        m2 = self.parsemanifest(A_SHORT_MANIFEST_V2)
        # Should have same content as A_SHORT_MANIFEST
        self.assertEqual(m1.text(), m2.text())

    def testParseManifestMetadata(self):
        # Metadata is for future-proofing and should be accepted but ignored
        m = self.parsemanifest(A_METADATA_MANIFEST)
        self.assertEqual(A_SHORT_MANIFEST, m.text())

    def testParseManifestStemCompression(self):
        m = self.parsemanifest(A_STEM_COMPRESSED_MANIFEST)
        self.assertIn('bar/baz/qux.py', m)
        self.assertIn('bar/qux/foo.py', m)
        self.assertIn('bar/qux/foz.py', m)
        self.assertIn(256 * 'x' + '/x', m)
        self.assertIn(256 * 'x' + '/y', m)
        self.assertEqual(A_STEM_COMPRESSED_MANIFEST, m.text(usemanifestv2=True))

    def testTextV2(self):
        m1 = self.parsemanifest(A_SHORT_MANIFEST)
        v2text = m1.text(usemanifestv2=True)
        self.assertEqual(A_SHORT_MANIFEST_V2, v2text)

    def testSetItem(self):
        want = BIN_HASH_1

        m = self.parsemanifest(EMTPY_MANIFEST)
        m['a'] = want
        self.assertIn('a', m)
        self.assertEqual(want, m['a'])
        self.assertEqual('a\0' + HASH_1 + '\n', m.text())

        m = self.parsemanifest(A_SHORT_MANIFEST)
        m['a'] = want
        self.assertEqual(want, m['a'])
        self.assertEqual('a\0' + HASH_1 + '\n' + A_SHORT_MANIFEST,
                         m.text())

    def testSetFlag(self):
        want = 'x'

        m = self.parsemanifest(EMTPY_MANIFEST)
        # first add a file; a file-less flag makes no sense
        m['a'] = BIN_HASH_1
        m.setflag('a', want)
        self.assertEqual(want, m.flags('a'))
        self.assertEqual('a\0' + HASH_1 + want + '\n', m.text())

        m = self.parsemanifest(A_SHORT_MANIFEST)
        # first add a file; a file-less flag makes no sense
        m['a'] = BIN_HASH_1
        m.setflag('a', want)
        self.assertEqual(want, m.flags('a'))
        self.assertEqual('a\0' + HASH_1 + want + '\n' + A_SHORT_MANIFEST,
                         m.text())

    def testCopy(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        m['a'] = BIN_HASH_1
        m2 = m.copy()
        del m
        del m2 # make sure we don't double free() anything

    def testCompaction(self):
        unhex = binascii.unhexlify
        h1, h2 = unhex(HASH_1), unhex(HASH_2)
        m = self.parsemanifest(A_SHORT_MANIFEST)
        m['alpha'] = h1
        m['beta'] = h2
        del m['foo']
        want = 'alpha\0%s\nbar/baz/qux.py\0%sl\nbeta\0%s\n' % (
            HASH_1, HASH_2, HASH_2)
        self.assertEqual(want, m.text())
        self.assertEqual(3, len(m))
        self.assertEqual(['alpha', 'bar/baz/qux.py', 'beta'], list(m))
        self.assertEqual(h1, m['alpha'])
        self.assertEqual(h2, m['bar/baz/qux.py'])
        self.assertEqual(h2, m['beta'])
        self.assertEqual('', m.flags('alpha'))
        self.assertEqual('l', m.flags('bar/baz/qux.py'))
        self.assertEqual('', m.flags('beta'))
        self.assertRaises(KeyError, lambda : m['foo'])

    def testSetGetNodeSuffix(self):
        clean = self.parsemanifest(A_SHORT_MANIFEST)
        m = self.parsemanifest(A_SHORT_MANIFEST)
        h = m['foo']
        f = m.flags('foo')
        want = h + 'a'
        # Merge code wants to set 21-byte fake hashes at times
        m['foo'] = want
        self.assertEqual(want, m['foo'])
        self.assertEqual([('bar/baz/qux.py', BIN_HASH_2),
                          ('foo', BIN_HASH_1 + 'a')],
                         list(m.iteritems()))
        # Sometimes it even tries a 22-byte fake hash, but we can
        # return 21 and it'll work out
        m['foo'] = want + '+'
        self.assertEqual(want, m['foo'])
        # make sure the suffix survives a copy
        match = matchmod.match('', '', ['re:foo'])
        m2 = m.matches(match)
        self.assertEqual(want, m2['foo'])
        self.assertEqual(1, len(m2))
        m2 = m.copy()
        self.assertEqual(want, m2['foo'])
        # suffix with iteration
        self.assertEqual([('bar/baz/qux.py', BIN_HASH_2),
                          ('foo', want)],
                         list(m.iteritems()))

        # shows up in diff
        self.assertEqual({'foo': ((want, f), (h, ''))}, m.diff(clean))
        self.assertEqual({'foo': ((h, ''), (want, f))}, clean.diff(m))

    def testMatchException(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        match = matchmod.match('', '', ['re:.*'])
        def filt(path):
            if path == 'foo':
                assert False
            return True
        match.matchfn = filt
        self.assertRaises(AssertionError, m.matches, match)

    def testRemoveItem(self):
        m = self.parsemanifest(A_SHORT_MANIFEST)
        del m['foo']
        self.assertRaises(KeyError, lambda : m['foo'])
        self.assertEqual(1, len(m))
        self.assertEqual(1, len(list(m)))
        # now restore and make sure everything works right
        m['foo'] = 'a' * 20
        self.assertEqual(2, len(m))
        self.assertEqual(2, len(list(m)))

    def testManifestDiff(self):
        MISSING = (None, '')
        addl = 'z-only-in-left\0' + HASH_1 + '\n'
        addr = 'z-only-in-right\0' + HASH_2 + 'x\n'
        left = self.parsemanifest(
            A_SHORT_MANIFEST.replace(HASH_1, HASH_3 + 'x') + addl)
        right = self.parsemanifest(A_SHORT_MANIFEST + addr)
        want = {
            'foo': ((BIN_HASH_3, 'x'),
                    (BIN_HASH_1, '')),
            'z-only-in-left': ((BIN_HASH_1, ''), MISSING),
            'z-only-in-right': (MISSING, (BIN_HASH_2, 'x')),
            }
        self.assertEqual(want, left.diff(right))

        want = {
            'bar/baz/qux.py': (MISSING, (BIN_HASH_2, 'l')),
            'foo': (MISSING, (BIN_HASH_3, 'x')),
            'z-only-in-left': (MISSING, (BIN_HASH_1, '')),
            }
        self.assertEqual(want, self.parsemanifest(EMTPY_MANIFEST).diff(left))

        want = {
            'bar/baz/qux.py': ((BIN_HASH_2, 'l'), MISSING),
            'foo': ((BIN_HASH_3, 'x'), MISSING),
            'z-only-in-left': ((BIN_HASH_1, ''), MISSING),
            }
        self.assertEqual(want, left.diff(self.parsemanifest(EMTPY_MANIFEST)))
        copy = right.copy()
        del copy['z-only-in-right']
        del right['foo']
        want = {
            'foo': (MISSING, (BIN_HASH_1, '')),
            'z-only-in-right': ((BIN_HASH_2, 'x'), MISSING),
            }
        self.assertEqual(want, right.diff(copy))

        short = self.parsemanifest(A_SHORT_MANIFEST)
        pruned = short.copy()
        del pruned['foo']
        want = {
            'foo': ((BIN_HASH_1, ''), MISSING),
            }
        self.assertEqual(want, short.diff(pruned))
        want = {
            'foo': (MISSING, (BIN_HASH_1, '')),
            }
        self.assertEqual(want, pruned.diff(short))
        want = {
            'bar/baz/qux.py': None,
            'foo': (MISSING, (BIN_HASH_1, '')),
            }
        self.assertEqual(want, pruned.diff(short, True))

    def testReversedLines(self):
        backwards = ''.join(
            l + '\n' for l in reversed(A_SHORT_MANIFEST.split('\n')) if l)
        try:
            self.parsemanifest(backwards)
            self.fail('Should have raised ValueError')
        except ValueError as v:
            self.assertIn('Manifest lines not in sorted order.', str(v))

    def testNoTerminalNewline(self):
        try:
            self.parsemanifest(A_SHORT_MANIFEST + 'wat')
            self.fail('Should have raised ValueError')
        except ValueError as v:
            self.assertIn('Manifest did not end in a newline.', str(v))

    def testNoNewLineAtAll(self):
        try:
            self.parsemanifest('wat')
            self.fail('Should have raised ValueError')
        except ValueError as v:
            self.assertIn('Manifest did not end in a newline.', str(v))

    def testHugeManifest(self):
        m = self.parsemanifest(A_HUGE_MANIFEST)
        self.assertEqual(HUGE_MANIFEST_ENTRIES, len(m))
        self.assertEqual(len(m), len(list(m)))

    def testMatchesMetadata(self):
        '''Tests matches() for a few specific files to make sure that both
        the set of files as well as their flags and nodeids are correct in
        the resulting manifest.'''
        m = self.parsemanifest(A_HUGE_MANIFEST)

        match = matchmod.match('/', '',
                ['file1', 'file200', 'file300'], exact=True)
        m2 = m.matches(match)

        w = ('file1\0%sx\n'
             'file200\0%sl\n'
             'file300\0%s\n') % (HASH_2, HASH_1, HASH_1)
        self.assertEqual(w, m2.text())

    def testMatchesNonexistentFile(self):
        '''Tests matches() for a small set of specific files, including one
        nonexistent file to make sure in only matches against existing files.
        '''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match('/', '',
                ['a/b/c/bar.txt', 'a/b/d/qux.py', 'readme.txt', 'nonexistent'],
                exact=True)
        m2 = m.matches(match)

        self.assertEqual(
                ['a/b/c/bar.txt', 'a/b/d/qux.py', 'readme.txt'],
                m2.keys())

    def testMatchesNonexistentDirectory(self):
        '''Tests matches() for a relpath match on a directory that doesn't
        actually exist.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match('/', '', ['a/f'], default='relpath')
        m2 = m.matches(match)

        self.assertEqual([], m2.keys())

    def testMatchesExactLarge(self):
        '''Tests matches() for files matching a large list of exact files.
        '''
        m = self.parsemanifest(A_HUGE_MANIFEST)

        flist = m.keys()[80:300]
        match = matchmod.match('/', '', flist, exact=True)
        m2 = m.matches(match)

        self.assertEqual(flist, m2.keys())

    def testMatchesFull(self):
        '''Tests matches() for what should be a full match.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match('/', '', [''])
        m2 = m.matches(match)

        self.assertEqual(m.keys(), m2.keys())

    def testMatchesDirectory(self):
        '''Tests matches() on a relpath match on a directory, which should
        match against all files within said directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match('/', '', ['a/b'], default='relpath')
        m2 = m.matches(match)

        self.assertEqual([
            'a/b/c/bar.py', 'a/b/c/bar.txt', 'a/b/c/foo.py', 'a/b/c/foo.txt',
            'a/b/d/baz.py', 'a/b/d/qux.py', 'a/b/d/ten.txt', 'a/b/dog.py',
            'a/b/fish.py'], m2.keys())

    def testMatchesExactPath(self):
        '''Tests matches() on an exact match on a directory, which should
        result in an empty manifest because you can't perform an exact match
        against a directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match('/', '', ['a/b'], exact=True)
        m2 = m.matches(match)

        self.assertEqual([], m2.keys())

    def testMatchesCwd(self):
        '''Tests matches() on a relpath match with the current directory ('.')
        when not in the root directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match('/', 'a/b', ['.'], default='relpath')
        m2 = m.matches(match)

        self.assertEqual([
            'a/b/c/bar.py', 'a/b/c/bar.txt', 'a/b/c/foo.py', 'a/b/c/foo.txt',
            'a/b/d/baz.py', 'a/b/d/qux.py', 'a/b/d/ten.txt', 'a/b/dog.py',
            'a/b/fish.py'], m2.keys())

    def testMatchesWithPattern(self):
        '''Tests matches() for files matching a pattern that reside
        deeper than the specified directory.'''
        m = self.parsemanifest(A_DEEPER_MANIFEST)

        match = matchmod.match('/', '', ['a/b/*/*.txt'])
        m2 = m.matches(match)

        self.assertEqual(
                ['a/b/c/bar.txt', 'a/b/c/foo.txt', 'a/b/d/ten.txt'],
                m2.keys())

class testmanifestdict(unittest.TestCase, basemanifesttests):
    def parsemanifest(self, text):
        return manifestmod.manifestdict(text)

class testtreemanifest(unittest.TestCase, basemanifesttests):
    def parsemanifest(self, text):
        return manifestmod.treemanifest('', text)

if __name__ == '__main__':
    silenttestrunner.main(__name__)