branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
#!/usr/bin/env python3
# like ls -l, but do not print date, user, or non-common mode bit, to avoid
# using globs in tests.
import os
import stat
import sys
def modestr(st):
mode = st.st_mode
result = ''
if mode & stat.S_IFDIR:
result += 'd'
else:
result += '-'
for owner in ['USR', 'GRP', 'OTH']:
for action in ['R', 'W', 'X']:
if mode & getattr(stat, 'S_I%s%s' % (action, owner)):
result += action.lower()
else:
result += '-'
return result
def sizestr(st):
if st.st_mode & stat.S_IFREG:
return '%7d' % st.st_size
else:
# do not show size for non regular files
return ' ' * 7
os.chdir((sys.argv[1:] + ['.'])[0])
for name in sorted(os.listdir('.')):
st = os.stat(name)
print('%s %s %s' % (modestr(st), sizestr(st), name))