view tests/test-propertycache.py @ 30561:7c0c722d568d

bdiff: early pruning of common prefix before doing expensive computations

It seems quite common that files don't change completely. New lines are often
pretty much appended, and modifications will often only change a small section
of the file which on average will be in the middle.

There can thus be a big win by pruning a common prefix before starting the more
expensive search for longest common substrings.

Worst case, it will scan through a long sequence of similar bytes without
encountering a newline. Splitlines will then have to do the same again ...
twice for each side. If similar lines are found, splitlines will save the
double iteration and hashing of the lines ... plus there will be less lines to
find common substrings in.

This change might in some cases make the algorith pick shorter or less optimal
common substrings. We can't have the cake and eat it.

This make hg --time bundle --base null -r 4.0 go from 14.5 to 15 s - a 3%
increase.

On mozilla-unified:
perfbdiff -m 3041e4d59df2
! wall 0.053088 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) to
! wall 0.024618 comb 0.020000 user 0.020000 sys 0.000000 (best of 116)
perfbdiff 0e9928989e9c --alldata --count 10
! wall 0.702075 comb 0.700000 user 0.700000 sys 0.000000 (best of 15) to
! wall 0.579235 comb 0.580000 user 0.580000 sys 0.000000 (best of 18)

"""test behavior of propertycache and unfiltered propertycache

The repoview overlay is quite complex. We test the behavior of
property cache of both localrepo and repoview to prevent
regression."""

from __future__ import absolute_import, print_function
import os
import subprocess

from mercurial import (
    hg,
    localrepo,
    ui as uimod,
    util,
)

# create some special property cache that trace they call

calllog = []
@util.propertycache
def testcachedfoobar(repo):
    name = repo.filtername
    if name is None:
        name = ''
    val = len(name)
    calllog.append(val)
    return val

unficalllog = []
@localrepo.unfilteredpropertycache
def testcachedunfifoobar(repo):
    name = repo.filtername
    if name is None:
        name = ''
    val = 100 + len(name)
    unficalllog.append(val)
    return val

#plug them on repo
localrepo.localrepository.testcachedfoobar = testcachedfoobar
localrepo.localrepository.testcachedunfifoobar = testcachedunfifoobar


# Create an empty repo and instantiate it. It is important to run
# these tests on the real object to detect regression.
repopath = os.path.join(os.environ['TESTTMP'], 'repo')
assert subprocess.call(['hg', 'init', repopath]) == 0
ui = uimod.ui.load()
repo = hg.repository(ui, path=repopath).unfiltered()


print('')
print('=== property cache ===')
print('')
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= first access on unfiltered, should do a call')
print('access:', repo.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= second access on unfiltered, should not do call')
print('access', repo.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= first access on "visible" view, should do a call')
visibleview = repo.filtered('visible')
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= second access on "visible view", should not do call')
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= no effect on other view')
immutableview = repo.filtered('immutable')
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedfoobar', 'NOCACHE'))
print('access:', immutableview.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedfoobar', 'NOCACHE'))

# unfiltered property cache test
print('')
print('')
print('=== unfiltered property cache ===')
print('')
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= first access on unfiltered, should do a call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= second access on unfiltered, should not do call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= access on view should use the unfiltered cache')
print('access (unfiltered):      ', repo.testcachedunfifoobar)
print('access ("visible" view):  ', visibleview.testcachedunfifoobar)
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= even if we clear the unfiltered cache')
del repo.__dict__['testcachedunfifoobar']
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))
print('unficalllog:', unficalllog)
print('access ("visible" view):  ', visibleview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))
print('access (unfiltered):      ', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))