branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
Test applying context diffs
$ cat > writepatterns.py <<EOF
> import sys
>
> path = sys.argv[1]
> lasteol = sys.argv[2] == '1'
> patterns = sys.argv[3:]
>
> fp = open(path, 'wb')
> for i, pattern in enumerate(patterns):
> count = int(pattern[0:-1])
> char = pattern[-1].encode('utf8') + b'\n'
> if not lasteol and i == len(patterns) - 1:
> fp.write((char * count)[:-1])
> else:
> fp.write(char * count)
> fp.close()
> EOF
$ cat > cat.py <<EOF
> import sys
> from mercurial.utils import procutil, stringutil
> procutil.stdout.write(b'%s\n'
> % stringutil.pprint(open(sys.argv[1], 'rb').read()))
> EOF
Initialize the test repository
$ hg init repo
$ cd repo
$ "$PYTHON" ../writepatterns.py a 0 5A 1B 5C 1D
$ "$PYTHON" ../writepatterns.py b 1 1A 1B
$ "$PYTHON" ../writepatterns.py c 1 5A
$ "$PYTHON" ../writepatterns.py d 1 5A 1B
$ hg add
adding a
adding b
adding c
adding d
$ hg ci -m addfiles
Add file, missing a last end of line
$ hg import --no-commit - <<EOF
> *** /dev/null 2010-10-16 18:05:49.000000000 +0200
> --- b/newnoeol 2010-10-16 18:23:26.000000000 +0200
> ***************
> *** 0 ****
> --- 1,2 ----
> + a
> + b
> \ No newline at end of file
> *** a/a Sat Oct 16 16:35:51 2010
> --- b/a Sat Oct 16 16:35:51 2010
> ***************
> *** 3,12 ****
> A
> A
> A
> ! B
> C
> C
> C
> C
> C
> ! D
> \ No newline at end of file
> --- 3,13 ----
> A
> A
> A
> ! E
> C
> C
> C
> C
> C
> ! F
> ! F
>
> *** a/b 2010-10-16 18:40:38.000000000 +0200
> --- /dev/null 2010-10-16 18:05:49.000000000 +0200
> ***************
> *** 1,2 ****
> - A
> - B
> --- 0 ----
> *** a/c Sat Oct 16 21:34:26 2010
> --- b/c Sat Oct 16 21:34:27 2010
> ***************
> *** 3,5 ****
> --- 3,7 ----
> A
> A
> A
> + B
> + B
> *** a/d Sat Oct 16 21:47:20 2010
> --- b/d Sat Oct 16 21:47:22 2010
> ***************
> *** 2,6 ****
> A
> A
> A
> - A
> - B
> --- 2,4 ----
> EOF
applying patch from stdin
$ hg st
M a
M c
M d
A newnoeol
R b
What's in a
$ "$PYTHON" ../cat.py a
'A\nA\nA\nA\nA\nE\nC\nC\nC\nC\nC\nF\nF\n'
$ "$PYTHON" ../cat.py newnoeol
'a\nb'
$ "$PYTHON" ../cat.py c
'A\nA\nA\nA\nA\nB\nB\n'
$ "$PYTHON" ../cat.py d
'A\nA\nA\nA\n'
$ cd ..