sapling/eden/scm/tests/test-filecache.py

from __future__ import absolute_import, print_function

import os
import subprocess
import sys

from edenscm.mercurial import (
    extensions,
    hg,
    localrepo,
    ui as uimod,
    util,
    vfs as vfsmod,
)


try:
    xrange(0)
except NameError:
    xrange = range


class fakerepo(object):
    def __init__(self):
        self._filecache = {}

    class fakevfs(object):
        def join(self, p):
            return p

    vfs = localvfs = sharedvfs = fakevfs()

    def unfiltered(self):
        return self

    def sjoin(self, p):
        return p

    @localrepo.repofilecache("x", "y")
    def cached(self):
        print("creating")
        return "string from function"

    def invalidate(self):
        for k in self._filecache:
            try:
                delattr(self, k)
            except AttributeError:
                pass


def basic(repo):
    print("* neither file exists")
    # calls function
    repo.cached

    repo.invalidate()
    print("* neither file still exists")
    # uses cache
    repo.cached

    # create empty file
    f = open("x", "w")
    f.close()
    repo.invalidate()
    print("* empty file x created")
    # should recreate the object
    repo.cached

    f = open("x", "w")
    f.write("a")
    f.close()
    repo.invalidate()
    print("* file x changed size")
    # should recreate the object
    repo.cached

    repo.invalidate()
    print("* nothing changed with either file")
    # stats file again, reuses object
    repo.cached

    # atomic replace file, size doesn't change
    # hopefully st_mtime doesn't change as well so this doesn't use the cache
    # because of inode change
    f = vfsmod.vfs(".")("x", "w", atomictemp=True)
    f.write("b")
    f.close()

    repo.invalidate()
    print("* file x changed inode")
    repo.cached

    # create empty file y
    f = open("y", "w")
    f.close()
    repo.invalidate()
    print("* empty file y created")
    # should recreate the object
    repo.cached

    f = open("y", "w")
    f.write("A")
    f.close()
    repo.invalidate()
    print("* file y changed size")
    # should recreate the object
    repo.cached

    f = vfsmod.vfs(".")("y", "w", atomictemp=True)
    f.write("B")
    f.close()

    repo.invalidate()
    print("* file y changed inode")
    repo.cached

    f = vfsmod.vfs(".")("x", "w", atomictemp=True)
    f.write("c")
    f.close()
    f = vfsmod.vfs(".")("y", "w", atomictemp=True)
    f.write("C")
    f.close()

    repo.invalidate()
    print("* both files changed inode")
    repo.cached


def test_filecache_synced():
    # test old behavior that caused filecached properties to go out of sync
    os.system("hg init && echo a >> a && hg ci -qAm.")
    repo = hg.repository(uimod.ui.load())
    # first rollback clears the filecache, but changelog to stays in __dict__
    repo.rollback()
    repo.commit(".")
    # second rollback comes along and touches the changelog externally
    # (file is moved)
    repo.rollback()
    # but since changelog isn't under the filecache control anymore, we don't
    # see that it changed, and return the old changelog without reconstructing
    # it
    repo.commit(".")


def setbeforeget(repo):
    os.remove("x")
    os.remove("y")
    repo.cached = "string set externally"
    repo.invalidate()
    print("* neither file exists")
    print(repo.cached)
    repo.invalidate()
    f = open("x", "w")
    f.write("a")
    f.close()
    print("* file x created")
    print(repo.cached)

    repo.cached = "string 2 set externally"
    repo.invalidate()
    print("* string set externally again")
    print(repo.cached)

    repo.invalidate()
    f = open("y", "w")
    f.write("b")
    f.close()
    print("* file y created")
    print(repo.cached)


def antiambiguity():
    filename = "ambigcheck"

    # try some times, because reproduction of ambiguity depends on
    # "filesystem time"
    for i in xrange(5):
        fp = open(filename, "w")
        fp.write("FOO")
        fp.close()

        oldstat = util.stat(filename)
        if oldstat.st_ctime != oldstat.st_mtime:
            # subsequent changing never causes ambiguity
            continue

        repetition = 3

        # repeat changing via checkambigatclosing, to examine whether
        # st_mtime is advanced multiple times as expected
        for i in xrange(repetition):
            # explicit closing
            fp = vfsmod.checkambigatclosing(open(filename, "a"))
            fp.write("FOO")
            fp.close()

            # implicit closing by "with" statement
            with vfsmod.checkambigatclosing(open(filename, "a")) as fp:
                fp.write("BAR")

        newstat = os.stat(filename)
        if oldstat.st_ctime != newstat.st_ctime:
            # timestamp ambiguity was naturally avoided while repetition
            continue

        # st_mtime should be advanced "repetition * 2" times, because
        # all changes occurred at same time (in sec)
        expected = (oldstat.st_mtime + repetition * 2) & 0x7FFFFFFF
        if newstat.st_mtime != expected:
            print(
                "'newstat.st_mtime %s is not %s (as %s + %s * 2)"
                % (newstat.st_mtime, expected, oldstat.st_mtime, repetition)
            )

        # no more examination is needed regardless of result
        break
    else:
        # This platform seems too slow to examine anti-ambiguity
        # of file timestamp (or test happened to be executed at
        # bad timing). Exit silently in this case, because running
        # on other faster platforms can detect problems
        pass


print("basic:")
print()
basic(fakerepo())
print()
test_filecache_synced()
print()
print("setbeforeget:")
print()
setbeforeget(fakerepo())
print()
print("antiambiguity:")
print()
antiambiguity()