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
from __future__ import annotations
import os
import time
# work around check-code complains
#
# This is a simple log level module doing simple test related work, we can't
# import more things, and we do not need it.
environ = getattr(os, 'environ')
def wait_on_cfg(ui, cfg, timeout=10):
"""synchronize on the `cfg` config path
Use this to synchronize commands during race tests.
"""
full_config = b'sync.' + cfg
wait_config = full_config + b'-timeout'
sync_path = ui.config(b'devel', full_config)
if sync_path is not None:
timeout = ui.config(b'devel', wait_config)
ready_path = sync_path + b'.waiting'
write_file(ready_path)
wait_file(sync_path, timeout=timeout)
def _timeout_factor():
"""return the current modification to timeout"""
default = int(environ.get('HGTEST_TIMEOUT_DEFAULT', 360))
current = int(environ.get('HGTEST_TIMEOUT', default))
if current == 0:
return 1
return current / float(default)
def wait_file(path, timeout=10):
timeout *= _timeout_factor()
start = time.time()
while not os.path.exists(path):
if timeout and time.time() - start > timeout:
raise RuntimeError(b"timed out waiting for file: %s" % path)
time.sleep(0.01)
def write_file(path, content=b''):
if content:
write_path = b'%s.tmp' % path
else:
write_path = path
with open(write_path, 'wb') as f:
f.write(content)
if path != write_path:
os.rename(write_path, path)