~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005-2009, 2011 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

import os

import stat

import time

from bzrlib import osutils

from bzrlib.errors import BzrError

from bzrlib.hashcache import HashCache

from bzrlib.tests import (

    OsFifoFeature,

    TestCaseInTempDir,

    )

def sha1(t):

    return osutils.sha(t).hexdigest()

def pause():

    time.sleep(5.0)

class TestHashCache(TestCaseInTempDir):

    """Test the hashcache against a real directory"""

    def make_hashcache(self):

        # make a dummy bzr directory just to hold the cache

        os.mkdir('.bzr')

        hc = HashCache('.', '.bzr/stat-cache')

        return hc

    def reopen_hashcache(self):

        hc = HashCache('.', '.bzr/stat-cache')

        hc.read()

        return hc

    def test_hashcache_initial_miss(self):

        """Get correct hash from an empty hashcache"""

        hc = self.make_hashcache()

        self.build_tree_contents([('foo', 'hello')])

        self.assertEquals(hc.get_sha1('foo'),

                          'aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d')

        self.assertEquals(hc.miss_count, 1)

        self.assertEquals(hc.hit_count, 0)

    def test_hashcache_new_file(self):

        hc = self.make_hashcache()

        self.build_tree_contents([('foo', 'goodbye')])

        # now read without pausing; it may not be possible to cache it as its

        # so new

        self.assertEquals(hc.get_sha1('foo'), sha1('goodbye'))

    def test_hashcache_nonexistent_file(self):

        hc = self.make_hashcache()

        self.assertEquals(hc.get_sha1('no-name-yet'), None)

    def test_hashcache_replaced_file(self):

        hc = self.make_hashcache()

        self.build_tree_contents([('foo', 'goodbye')])

        self.assertEquals(hc.get_sha1('foo'), sha1('goodbye'))

        os.remove('foo')

        self.assertEquals(hc.get_sha1('foo'), None)

        self.build_tree_contents([('foo', 'new content')])

        self.assertEquals(hc.get_sha1('foo'), sha1('new content'))

    def test_hashcache_not_file(self):

        hc = self.make_hashcache()

        self.build_tree(['subdir/'])

        self.assertEquals(hc.get_sha1('subdir'), None)

    def test_hashcache_load(self):

        hc = self.make_hashcache()

        self.build_tree_contents([('foo', 'contents')])

        pause()

        self.assertEquals(hc.get_sha1('foo'), sha1('contents'))

        hc.write()

        hc = self.reopen_hashcache()

        self.assertEquals(hc.get_sha1('foo'), sha1('contents'))

        self.assertEquals(hc.hit_count, 1)

    def test_hammer_hashcache(self):

        hc = self.make_hashcache()

        for i in xrange(10000):

            self.log('start writing at %s', time.time())

            f = file('foo', 'w')

            try:

                last_content = '%08x' % i

                f.write(last_content)

            finally:

                f.close()

            last_sha1 = sha1(last_content)

            self.log("iteration %d: %r -> %r",

                     i, last_content, last_sha1)

            got_sha1 = hc.get_sha1('foo')

            self.assertEquals(got_sha1, last_sha1)

            hc.write()

            hc = self.reopen_hashcache()

    def test_hashcache_raise(self):

        """check that hashcache can raise BzrError"""

        self.requireFeature(OsFifoFeature)

        hc = self.make_hashcache()

        os.mkfifo('a')

        # It's possible that the system supports fifos but the filesystem

        # can't.  In that case we should skip at this point.  But in fact

        # such combinations don't usually occur for the filesystem where

        # people test bzr.

        self.assertRaises(BzrError, hc.get_sha1, 'a')

class FakeHashCache(HashCache):

    """Hashcache that consults a fake clock rather than the real one.

    This lets us examine how old or new files would be handled, without

    actually having to wait for time to pass.

    """

    def __init__(self):

        # set root and cache file name to none to make sure we won't touch the

        # real filesystem

        HashCache.__init__(self, '.', 'hashcache')

        self._files = {}

        # simulated clock running forward as operations happen

        self._clock = 0

    def put_file(self, filename, file_contents):

        abspath = './' + filename

        self._files[abspath] = (file_contents, self._clock)

    def _fingerprint(self, abspath, fs=None):

        entry = self._files[abspath]

        return (len(entry[0]),

                entry[1], entry[1],

                10, 20,

                stat.S_IFREG | 0600)

    def _really_sha1_file(self, abspath, filters):

        if abspath in self._files:

            return sha1(self._files[abspath][0])

        else:

            return None

    def _cutoff_time(self):

        return self._clock - 2

    def pretend_to_sleep(self, secs):

        self._clock += secs

class TestHashCacheFakeFilesystem(TestCaseInTempDir):

    """Tests the hashcache using a simulated OS.

    """

    def make_hashcache(self):

        return FakeHashCache()

    def test_hashcache_miss_new_file(self):

        """A new file gives the right sha1 but misses"""

        hc = self.make_hashcache()

        hc.put_file('foo', 'hello')

        self.assertEquals(hc.get_sha1('foo'), sha1('hello'))

        self.assertEquals(hc.miss_count, 1)

        self.assertEquals(hc.hit_count, 0)

        # if we try again it's still too new;

        self.assertEquals(hc.get_sha1('foo'), sha1('hello'))

        self.assertEquals(hc.miss_count, 2)

        self.assertEquals(hc.hit_count, 0)

    def test_hashcache_old_file(self):

        """An old file gives the right sha1 and hits"""

        hc = self.make_hashcache()

        hc.put_file('foo', 'hello')

        hc.pretend_to_sleep(20)

        # file is new; should get the correct hash but miss

        self.assertEquals(hc.get_sha1('foo'), sha1('hello'))

        self.assertEquals(hc.miss_count, 1)

        self.assertEquals(hc.hit_count, 0)

        # and can now be hit

        self.assertEquals(hc.get_sha1('foo'), sha1('hello'))

        self.assertEquals(hc.miss_count, 1)

        self.assertEquals(hc.hit_count, 1)

        hc.pretend_to_sleep(3)

        # and again

        self.assertEquals(hc.get_sha1('foo'), sha1('hello'))

        self.assertEquals(hc.miss_count, 1)

        self.assertEquals(hc.hit_count, 2)

    def test_hashcache_invalidates(self):

        hc = self.make_hashcache()

        hc.put_file('foo', 'hello')

        hc.pretend_to_sleep(20)

        hc.get_sha1('foo')

        hc.put_file('foo', 'h1llo')

        self.assertEquals(hc.get_sha1('foo'), sha1('h1llo'))

        self.assertEquals(hc.miss_count, 2)

        self.assertEquals(hc.hit_count, 0)