view tests/test-remotefilelog-datapack.py @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

#!/usr/bin/env python
from __future__ import absolute_import, print_function

import hashlib
import os
import random
import shutil
import stat
import struct
import sys
import tempfile
import time
import unittest

import silenttestrunner

# Load the local remotefilelog, not the system one
sys.path[0:0] = [os.path.join(os.path.dirname(__file__), '..')]
from mercurial.node import sha1nodeconstants
from mercurial import policy

if not policy._packageprefs.get(policy.policy, (False, False))[1]:
    if __name__ == '__main__':
        msg = "skipped: pure module not available with module policy:"
        print(msg, policy.policy, file=sys.stderr)
        sys.exit(80)

from mercurial import (
    pycompat,
    ui as uimod,
)
from hgext.remotefilelog import (
    basepack,
    constants,
    datapack,
)


class datapacktestsbase(object):
    def __init__(self, datapackreader, paramsavailable):
        self.datapackreader = datapackreader
        self.paramsavailable = paramsavailable

    def setUp(self):
        self.tempdirs = []

    def tearDown(self):
        for d in self.tempdirs:
            shutil.rmtree(d)

    def makeTempDir(self):
        tempdir = pycompat.bytestr(tempfile.mkdtemp())
        self.tempdirs.append(tempdir)
        return tempdir

    def getHash(self, content):
        return hashlib.sha1(content).digest()

    def getFakeHash(self):
        return b''.join(
            pycompat.bytechr(random.randint(0, 255)) for _ in range(20)
        )

    def createPack(self, revisions=None, packdir=None):
        if revisions is None:
            revisions = [
                (
                    b"filename",
                    self.getFakeHash(),
                    sha1nodeconstants.nullid,
                    b"content",
                )
            ]

        if packdir is None:
            packdir = self.makeTempDir()

        packer = datapack.mutabledatapack(uimod.ui(), packdir, version=2)

        for args in revisions:
            filename, node, base, content = args[0:4]
            # meta is optional
            meta = None
            if len(args) > 4:
                meta = args[4]
            packer.add(filename, node, base, content, metadata=meta)

        path = packer.close()
        return self.datapackreader(path)

    def _testAddSingle(self, content):
        """Test putting a simple blob into a pack and reading it out."""
        filename = b"foo"
        node = self.getHash(content)

        revisions = [(filename, node, sha1nodeconstants.nullid, content)]
        pack = self.createPack(revisions)
        if self.paramsavailable:
            self.assertEqual(
                pack.params.fanoutprefix, basepack.SMALLFANOUTPREFIX
            )

        chain = pack.getdeltachain(filename, node)
        self.assertEqual(content, chain[0][4])

    def testAddSingle(self):
        self._testAddSingle(b'')

    def testAddSingleEmpty(self):
        self._testAddSingle(b'abcdef')

    def testAddMultiple(self):
        """Test putting multiple unrelated blobs into a pack and reading them
        out.
        """
        revisions = []
        for i in range(10):
            filename = b"foo%d" % i
            content = b"abcdef%d" % i
            node = self.getHash(content)
            revisions.append((filename, node, self.getFakeHash(), content))

        pack = self.createPack(revisions)

        for filename, node, base, content in revisions:
            entry = pack.getdelta(filename, node)
            self.assertEqual((content, filename, base, {}), entry)

            chain = pack.getdeltachain(filename, node)
            self.assertEqual(content, chain[0][4])

    def testAddDeltas(self):
        """Test putting multiple delta blobs into a pack and read the chain."""
        revisions = []
        filename = b"foo"
        lastnode = sha1nodeconstants.nullid
        for i in range(10):
            content = b"abcdef%d" % i
            node = self.getHash(content)
            revisions.append((filename, node, lastnode, content))
            lastnode = node

        pack = self.createPack(revisions)

        entry = pack.getdelta(filename, revisions[0][1])
        realvalue = (revisions[0][3], filename, revisions[0][2], {})
        self.assertEqual(entry, realvalue)

        # Test that the chain for the final entry has all the others
        chain = pack.getdeltachain(filename, node)
        for i in range(10):
            content = b"abcdef%d" % i
            self.assertEqual(content, chain[-i - 1][4])

    def testPackMany(self):
        """Pack many related and unrelated objects."""
        # Build a random pack file
        revisions = []
        blobs = {}
        random.seed(0)
        for i in range(100):
            filename = b"filename-%d" % i
            filerevs = []
            for j in range(random.randint(1, 100)):
                content = b"content-%d" % j
                node = self.getHash(content)
                lastnode = sha1nodeconstants.nullid
                if len(filerevs) > 0:
                    lastnode = filerevs[random.randint(0, len(filerevs) - 1)]
                filerevs.append(node)
                blobs[(filename, node, lastnode)] = content
                revisions.append((filename, node, lastnode, content))

        pack = self.createPack(revisions)

        # Verify the pack contents
        for (filename, node, lastnode), content in sorted(blobs.items()):
            chain = pack.getdeltachain(filename, node)
            for entry in chain:
                expectedcontent = blobs[(entry[0], entry[1], entry[3])]
                self.assertEqual(entry[4], expectedcontent)

    def testPackMetadata(self):
        revisions = []
        for i in range(100):
            filename = b'%d.txt' % i
            content = b'put-something-here \n' * i
            node = self.getHash(content)
            meta = {
                constants.METAKEYFLAG: i ** 4,
                constants.METAKEYSIZE: len(content),
                b'Z': b'random_string',
                b'_': b'\0' * i,
            }
            revisions.append(
                (filename, node, sha1nodeconstants.nullid, content, meta)
            )
        pack = self.createPack(revisions)
        for name, node, x, content, origmeta in revisions:
            parsedmeta = pack.getmeta(name, node)
            # flag == 0 should be optimized out
            if origmeta[constants.METAKEYFLAG] == 0:
                del origmeta[constants.METAKEYFLAG]
            self.assertEqual(parsedmeta, origmeta)

    def testGetMissing(self):
        """Test the getmissing() api."""
        revisions = []
        filename = b"foo"
        lastnode = sha1nodeconstants.nullid
        for i in range(10):
            content = b"abcdef%d" % i
            node = self.getHash(content)
            revisions.append((filename, node, lastnode, content))
            lastnode = node

        pack = self.createPack(revisions)

        missing = pack.getmissing([(b"foo", revisions[0][1])])
        self.assertFalse(missing)

        missing = pack.getmissing(
            [(b"foo", revisions[0][1]), (b"foo", revisions[1][1])]
        )
        self.assertFalse(missing)

        fakenode = self.getFakeHash()
        missing = pack.getmissing(
            [(b"foo", revisions[0][1]), (b"foo", fakenode)]
        )
        self.assertEqual(missing, [(b"foo", fakenode)])

    def testAddThrows(self):
        pack = self.createPack()

        try:
            pack.add(b'filename', sha1nodeconstants.nullid, b'contents')
            self.assertTrue(False, "datapack.add should throw")
        except RuntimeError:
            pass

    def testBadVersionThrows(self):
        pack = self.createPack()
        path = pack.path + b'.datapack'
        with open(path, 'rb') as f:
            raw = f.read()
        raw = struct.pack('!B', 255) + raw[1:]
        os.chmod(path, os.stat(path).st_mode | stat.S_IWRITE)
        with open(path, 'wb+') as f:
            f.write(raw)

        try:
            self.datapackreader(pack.path)
            self.assertTrue(False, "bad version number should have thrown")
        except RuntimeError:
            pass

    def testMissingDeltabase(self):
        fakenode = self.getFakeHash()
        revisions = [(b"filename", fakenode, self.getFakeHash(), b"content")]
        pack = self.createPack(revisions)
        chain = pack.getdeltachain(b"filename", fakenode)
        self.assertEqual(len(chain), 1)

    def testLargePack(self):
        """Test creating and reading from a large pack with over X entries.
        This causes it to use a 2^16 fanout table instead."""
        revisions = []
        blobs = {}
        total = basepack.SMALLFANOUTCUTOFF + 1
        for i in pycompat.xrange(total):
            filename = b"filename-%d" % i
            content = filename
            node = self.getHash(content)
            blobs[(filename, node)] = content
            revisions.append(
                (filename, node, sha1nodeconstants.nullid, content)
            )

        pack = self.createPack(revisions)
        if self.paramsavailable:
            self.assertEqual(
                pack.params.fanoutprefix, basepack.LARGEFANOUTPREFIX
            )

        for (filename, node), content in blobs.items():
            actualcontent = pack.getdeltachain(filename, node)[0][4]
            self.assertEqual(actualcontent, content)

    def testPacksCache(self):
        """Test that we remember the most recent packs while fetching the delta
        chain."""

        packdir = self.makeTempDir()
        deltachains = []

        numpacks = 10
        revisionsperpack = 100

        for i in range(numpacks):
            chain = []
            revision = (
                b'%d' % i,
                self.getFakeHash(),
                sha1nodeconstants.nullid,
                b"content",
            )

            for _ in range(revisionsperpack):
                chain.append(revision)
                revision = (
                    b'%d' % i,
                    self.getFakeHash(),
                    revision[1],
                    self.getFakeHash(),
                )

            self.createPack(chain, packdir)
            deltachains.append(chain)

        class testdatapackstore(datapack.datapackstore):
            # Ensures that we are not keeping everything in the cache.
            DEFAULTCACHESIZE = numpacks // 2

        store = testdatapackstore(uimod.ui(), packdir)

        random.shuffle(deltachains)
        for randomchain in deltachains:
            revision = random.choice(randomchain)
            chain = store.getdeltachain(revision[0], revision[1])

            mostrecentpack = next(iter(store.packs), None)
            self.assertEqual(
                mostrecentpack.getdeltachain(revision[0], revision[1]), chain
            )

            self.assertEqual(randomchain.index(revision) + 1, len(chain))

    # perf test off by default since it's slow
    def _testIndexPerf(self):
        random.seed(0)
        print("Multi-get perf test")
        packsizes = [
            100,
            10000,
            100000,
            500000,
            1000000,
            3000000,
        ]
        lookupsizes = [
            10,
            100,
            1000,
            10000,
            100000,
            1000000,
        ]
        for packsize in packsizes:
            revisions = []
            for i in pycompat.xrange(packsize):
                filename = b"filename-%d" % i
                content = b"content-%d" % i
                node = self.getHash(content)
                revisions.append(
                    (filename, node, sha1nodeconstants.nullid, content)
                )

            path = self.createPack(revisions).path

            # Perf of large multi-get
            import gc

            gc.disable()
            pack = self.datapackreader(path)
            for lookupsize in lookupsizes:
                if lookupsize > packsize:
                    continue
                random.shuffle(revisions)
                findnodes = [(rev[0], rev[1]) for rev in revisions]

                start = time.time()
                pack.getmissing(findnodes[:lookupsize])
                elapsed = time.time() - start
                print(
                    "%s pack %d lookups = %0.04f"
                    % (
                        ('%d' % packsize).rjust(7),
                        ('%d' % lookupsize).rjust(7),
                        elapsed,
                    )
                )

            print("")
            gc.enable()

        # The perf test is meant to produce output, so we always fail the test
        # so the user sees the output.
        raise RuntimeError("perf test always fails")


class datapacktests(datapacktestsbase, unittest.TestCase):
    def __init__(self, *args, **kwargs):
        datapacktestsbase.__init__(self, datapack.datapack, True)
        unittest.TestCase.__init__(self, *args, **kwargs)


# TODO:
# datapack store:
# - getmissing
# - GC two packs into one

if __name__ == '__main__':
    if pycompat.iswindows:
        sys.exit(80)  # Skip on Windows
    silenttestrunner.main(__name__)