merge: introduce new format for the state file
This new format will allow us to address common bugs while doing special merge
(graft, backout, rebaseā¦) and record user choice during conflict resolution.
The format is open so we can add more record for future usage.
This file still store hexified version of node to help human willing to debug
it by hand. The overhead or oversize are not expected be an issue.
The old format is still used. It will be written to disk along side the newer
format. And at parse time we detect if the data from old version of the
mergestate are different from the one in the new version file. If its the same,
both have most likely be written at the same time and you can trust the extra
data from the new file. If it differs, the old file have been written by an
older version of mercurial that did not knew about the new file. In that case we
use the content of the old file.
# branchmap.py - logic to computes, maintain and stores branchmap for local repo
#
# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from node import bin, hex, nullid, nullrev
import encoding
import util
def _filename(repo):
"""name of a branchcache file for a given repo or repoview"""
filename = "cache/branch2"
if repo.filtername:
filename = '%s-%s' % (filename, repo.filtername)
return filename
def read(repo):
try:
f = repo.opener(_filename(repo))
lines = f.read().split('\n')
f.close()
except (IOError, OSError):
return None
try:
cachekey = lines.pop(0).split(" ", 2)
last, lrev = cachekey[:2]
last, lrev = bin(last), int(lrev)
filteredhash = None
if len(cachekey) > 2:
filteredhash = bin(cachekey[2])
partial = branchcache(tipnode=last, tiprev=lrev,
filteredhash=filteredhash)
if not partial.validfor(repo):
# invalidate the cache
raise ValueError('tip differs')
for l in lines:
if not l:
continue
node, state, label = l.split(" ", 2)
if state not in 'oc':
raise ValueError('invalid branch state')
label = encoding.tolocal(label.strip())
if not node in repo:
raise ValueError('node %s does not exist' % node)
node = bin(node)
partial.setdefault(label, []).append(node)
if state == 'c':
partial._closednodes.add(node)
except KeyboardInterrupt:
raise
except Exception, inst:
if repo.ui.debugflag:
msg = 'invalid branchheads cache'
if repo.filtername is not None:
msg += ' (%s)' % repo.filtername
msg += ': %s\n'
repo.ui.warn(msg % inst)
partial = None
return partial
### Nearest subset relation
# Nearest subset of filter X is a filter Y so that:
# * Y is included in X,
# * X - Y is as small as possible.
# This create and ordering used for branchmap purpose.
# the ordering may be partial
subsettable = {None: 'visible',
'visible': 'served',
'served': 'immutable',
'immutable': 'base'}
def updatecache(repo):
cl = repo.changelog
filtername = repo.filtername
partial = repo._branchcaches.get(filtername)
revs = []
if partial is None or not partial.validfor(repo):
partial = read(repo)
if partial is None:
subsetname = subsettable.get(filtername)
if subsetname is None:
partial = branchcache()
else:
subset = repo.filtered(subsetname)
partial = subset.branchmap().copy()
extrarevs = subset.changelog.filteredrevs - cl.filteredrevs
revs.extend(r for r in extrarevs if r <= partial.tiprev)
revs.extend(cl.revs(start=partial.tiprev + 1))
if revs:
partial.update(repo, revs)
partial.write(repo)
assert partial.validfor(repo), filtername
repo._branchcaches[repo.filtername] = partial
class branchcache(dict):
"""A dict like object that hold branches heads cache.
This cache is used to avoid costly computations to determine all the
branch heads of a repo.
The cache is serialized on disk in the following format:
<tip hex node> <tip rev number> [optional filtered repo hex hash]
<branch head hex node> <open/closed state> <branch name>
<branch head hex node> <open/closed state> <branch name>
...
The first line is used to check if the cache is still valid. If the
branch cache is for a filtered repo view, an optional third hash is
included that hashes the hashes of all filtered revisions.
The open/closed state is represented by a single letter 'o' or 'c'.
This field can be used to avoid changelog reads when determining if a
branch head closes a branch or not.
"""
def __init__(self, entries=(), tipnode=nullid, tiprev=nullrev,
filteredhash=None, closednodes=None):
super(branchcache, self).__init__(entries)
self.tipnode = tipnode
self.tiprev = tiprev
self.filteredhash = filteredhash
# closednodes is a set of nodes that close their branch. If the branch
# cache has been updated, it may contain nodes that are no longer
# heads.
if closednodes is None:
self._closednodes = set()
else:
self._closednodes = closednodes
def _hashfiltered(self, repo):
"""build hash of revision filtered in the current cache
Tracking tipnode and tiprev is not enough to ensure validity of the
cache as they do not help to distinct cache that ignored various
revision bellow tiprev.
To detect such difference, we build a cache of all ignored revisions.
"""
cl = repo.changelog
if not cl.filteredrevs:
return None
key = None
revs = sorted(r for r in cl.filteredrevs if r <= self.tiprev)
if revs:
s = util.sha1()
for rev in revs:
s.update('%s;' % rev)
key = s.digest()
return key
def validfor(self, repo):
"""Is the cache content valid regarding a repo
- False when cached tipnode is unknown or if we detect a strip.
- True when cache is up to date or a subset of current repo."""
try:
return ((self.tipnode == repo.changelog.node(self.tiprev))
and (self.filteredhash == self._hashfiltered(repo)))
except IndexError:
return False
def _branchtip(self, heads):
'''Return tuple with last open head in heads and false,
otherwise return last closed head and true.'''
tip = heads[-1]
closed = True
for h in reversed(heads):
if h not in self._closednodes:
tip = h
closed = False
break
return tip, closed
def branchtip(self, branch):
'''Return the tipmost open head on branch head, otherwise return the
tipmost closed head on branch.
Raise KeyError for unknown branch.'''
return self._branchtip(self[branch])[0]
def branchheads(self, branch, closed=False):
heads = self[branch]
if not closed:
heads = [h for h in heads if h not in self._closednodes]
return heads
def iterbranches(self):
for bn, heads in self.iteritems():
yield (bn, heads) + self._branchtip(heads)
def copy(self):
"""return an deep copy of the branchcache object"""
return branchcache(self, self.tipnode, self.tiprev, self.filteredhash,
self._closednodes)
def write(self, repo):
try:
f = repo.opener(_filename(repo), "w", atomictemp=True)
cachekey = [hex(self.tipnode), str(self.tiprev)]
if self.filteredhash is not None:
cachekey.append(hex(self.filteredhash))
f.write(" ".join(cachekey) + '\n')
for label, nodes in sorted(self.iteritems()):
for node in nodes:
if node in self._closednodes:
state = 'c'
else:
state = 'o'
f.write("%s %s %s\n" % (hex(node), state,
encoding.fromlocal(label)))
f.close()
except (IOError, OSError, util.Abort):
# Abort may be raise by read only opener
pass
def update(self, repo, revgen):
"""Given a branchhead cache, self, that may have extra nodes or be
missing heads, and a generator of nodes that are strictly a superset of
heads missing, this function updates self to be correct.
"""
cl = repo.changelog
# collect new branch entries
newbranches = {}
getbranchinfo = cl.branchinfo
for r in revgen:
branch, closesbranch = getbranchinfo(r)
newbranches.setdefault(branch, []).append(r)
if closesbranch:
self._closednodes.add(cl.node(r))
# if older branchheads are reachable from new ones, they aren't
# really branchheads. Note checking parents is insufficient:
# 1 (branch a) -> 2 (branch b) -> 3 (branch a)
for branch, newheadrevs in newbranches.iteritems():
bheads = self.setdefault(branch, [])
bheadset = set(cl.rev(node) for node in bheads)
# This have been tested True on all internal usage of this function.
# run it again in case of doubt
# assert not (set(bheadrevs) & set(newheadrevs))
newheadrevs.sort()
bheadset.update(newheadrevs)
# This loop prunes out two kinds of heads - heads that are
# superseded by a head in newheadrevs, and newheadrevs that are not
# heads because an existing head is their descendant.
while newheadrevs:
latest = newheadrevs.pop()
if latest not in bheadset:
continue
ancestors = set(cl.ancestors([latest], min(bheadset)))
bheadset -= ancestors
bheadrevs = sorted(bheadset)
self[branch] = [cl.node(rev) for rev in bheadrevs]
tiprev = bheadrevs[-1]
if tiprev > self.tiprev:
self.tipnode = cl.node(tiprev)
self.tiprev = tiprev
if not self.validfor(repo):
# cache key are not valid anymore
self.tipnode = nullid
self.tiprev = nullrev
for heads in self.values():
tiprev = max(cl.rev(node) for node in heads)
if tiprev > self.tiprev:
self.tipnode = cl.node(tiprev)
self.tiprev = tiprev
self.filteredhash = self._hashfiltered(repo)