annotate tests/mockmakedate.py @ 51930:bc9ed92d4753

util: make `mmapread()` work on Windows again

522b4d729e89 started referencing `mmap.MAP_PRIVATE`, but that's not available on
Windows, so `hg version` worked, but `make local` did not.  That commit also
started calling the constructor with the fine-grained `flags` and `prot` args,
but those aren't available on Windows either[1] (though the backing C code
doesn't seem conditionalized to disallow usage of them).

I assume the change away from from the `access` arg was to provide the same
options, plus `MAP_POPULATE`.  Looking at the source code[2], they're not quite
the same- `ACCESS_READ` is equivalent to `flags = MAP_SHARED` and `prot = PROT_READ`.
`MAP_PRIVATE` is only used with `ACCESS_COPY`, which allows read and write.
Therefore, we can't quite get the same baseline flags on Windows, but this was
the status quo ante and `MAP_POPULATE` is a Linux thing, so presumably it works.

I realize that typically the OS differences are abstracted into the platform
modules, but I'm leaving it here so that it is obvious what the differences are
between the platforms.

[1] https://docs.python.org/3/library/mmap.html#mmap.mmap
[2] https://github.com/python/cpython/blob/5e0abb47886bc665eefdcc19fde985f803e49d4c/Modules/mmapmodule.c#L1539

# mock out util.makedate() to supply testable values


import os

from mercurial import pycompat
from mercurial.utils import dateutil


def mockmakedate():
    filename = os.path.join(os.environ['TESTTMP'], 'testtime')
    try:
        with open(filename, 'rb') as timef:
            time = float(timef.read()) + 1
    except IOError:
        time = 0.0
    with open(filename, 'wb') as timef:
        timef.write(pycompat.bytestr(time))
    return (time, 0)


dateutil.makedate = mockmakedate