# 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
import time
from array import array
from struct import calcsize, pack, unpack
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.vfs(_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.debug(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
self._revbranchcache = None
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.vfs(_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')
nodecount = 0
for label, nodes in sorted(self.iteritems()):
for node in nodes:
nodecount += 1
if node in self._closednodes:
state = 'c'
else:
state = 'o'
f.write("%s %s %s\n" % (hex(node), state,
encoding.fromlocal(label)))
f.close()
repo.ui.log('branchcache',
'wrote %s branch cache with %d labels and %d nodes\n',
repo.filtername, len(self), nodecount)
except (IOError, OSError, util.Abort), inst:
repo.ui.debug("couldn't write branch cache: %s\n" % inst)
# Abort may be raise by read only opener
pass
if self._revbranchcache:
self._revbranchcache.write(repo.unfiltered())
self._revbranchcache = None
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.
"""
starttime = time.time()
cl = repo.changelog
# collect new branch entries
newbranches = {}
urepo = repo.unfiltered()
self._revbranchcache = revbranchcache(urepo)
getbranchinfo = self._revbranchcache.branchinfo
ucl = urepo.changelog
for r in revgen:
branch, closesbranch = getbranchinfo(ucl, r)
newbranches.setdefault(branch, []).append(r)
if closesbranch:
self._closednodes.add(cl.node(r))
# fetch current topological heads to speed up filtering
topoheads = set(cl.headrevs())
# 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 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.
uncertain = bheadset - topoheads
if uncertain:
floorrev = min(uncertain)
ancestors = set(cl.ancestors(newheadrevs, floorrev))
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)
duration = time.time() - starttime
repo.ui.log('branchcache', 'updated %s branch cache in %.4f seconds\n',
repo.filtername, duration)
# Revision branch info cache
_rbcversion = '-v1'
_rbcnames = 'cache/rbc-names' + _rbcversion
_rbcrevs = 'cache/rbc-revs' + _rbcversion
# [4 byte hash prefix][4 byte branch name number with sign bit indicating open]
_rbcrecfmt = '>4sI'
_rbcrecsize = calcsize(_rbcrecfmt)
_rbcnodelen = 4
_rbcbranchidxmask = 0x7fffffff
_rbccloseflag = 0x80000000
class revbranchcache(object):
"""Persistent cache, mapping from revision number to branch name and close.
This is a low level cache, independent of filtering.
Branch names are stored in rbc-names in internal encoding separated by 0.
rbc-names is append-only, and each branch name is only stored once and will
thus have a unique index.
The branch info for each revision is stored in rbc-revs as constant size
records. The whole file is read into memory, but it is only 'parsed' on
demand. The file is usually append-only but will be truncated if repo
modification is detected.
The record for each revision contains the first 4 bytes of the
corresponding node hash, and the record is only used if it still matches.
Even a completely trashed rbc-revs fill thus still give the right result
while converging towards full recovery ... assuming no incorrectly matching
node hashes.
The record also contains 4 bytes where 31 bits contains the index of the
branch and the last bit indicate that it is a branch close commit.
The usage pattern for rbc-revs is thus somewhat similar to 00changelog.i
and will grow with it but be 1/8th of its size.
"""
def __init__(self, repo, readonly=True):
assert repo.filtername is None
self._names = [] # branch names in local encoding with static index
self._rbcrevs = array('c') # structs of type _rbcrecfmt
self._rbcsnameslen = 0
try:
bndata = repo.vfs.read(_rbcnames)
self._rbcsnameslen = len(bndata) # for verification before writing
self._names = [encoding.tolocal(bn) for bn in bndata.split('\0')]
except (IOError, OSError), inst:
repo.ui.debug("couldn't read revision branch cache names: %s\n" %
inst)
if readonly:
# don't try to use cache - fall back to the slow path
self.branchinfo = self._branchinfo
if self._names:
try:
data = repo.vfs.read(_rbcrevs)
self._rbcrevs.fromstring(data)
except (IOError, OSError), inst:
repo.ui.debug("couldn't read revision branch cache: %s\n" %
inst)
# remember number of good records on disk
self._rbcrevslen = min(len(self._rbcrevs) // _rbcrecsize,
len(repo.changelog))
if self._rbcrevslen == 0:
self._names = []
self._rbcnamescount = len(self._names) # number of good names on disk
self._namesreverse = dict((b, r) for r, b in enumerate(self._names))
def branchinfo(self, changelog, rev):
"""Return branch name and close flag for rev, using and updating
persistent cache."""
rbcrevidx = rev * _rbcrecsize
# if requested rev is missing, add and populate all missing revs
if len(self._rbcrevs) < rbcrevidx + _rbcrecsize:
first = len(self._rbcrevs) // _rbcrecsize
self._rbcrevs.extend('\0' * (len(changelog) * _rbcrecsize -
len(self._rbcrevs)))
for r in xrange(first, len(changelog)):
self._branchinfo(changelog, r)
# fast path: extract data from cache, use it if node is matching
reponode = changelog.node(rev)[:_rbcnodelen]
cachenode, branchidx = unpack(
_rbcrecfmt, buffer(self._rbcrevs, rbcrevidx, _rbcrecsize))
close = bool(branchidx & _rbccloseflag)
if close:
branchidx &= _rbcbranchidxmask
if cachenode == reponode:
return self._names[branchidx], close
# fall back to slow path and make sure it will be written to disk
self._rbcrevslen = min(self._rbcrevslen, rev)
return self._branchinfo(changelog, rev)
def _branchinfo(self, changelog, rev):
"""Retrieve branch info from changelog and update _rbcrevs"""
b, close = changelog.branchinfo(rev)
if b in self._namesreverse:
branchidx = self._namesreverse[b]
else:
branchidx = len(self._names)
self._names.append(b)
self._namesreverse[b] = branchidx
reponode = changelog.node(rev)
if close:
branchidx |= _rbccloseflag
rbcrevidx = rev * _rbcrecsize
rec = array('c')
rec.fromstring(pack(_rbcrecfmt, reponode, branchidx))
self._rbcrevs[rbcrevidx:rbcrevidx + _rbcrecsize] = rec
return b, close
def write(self, repo):
"""Save branch cache if it is dirty."""
if self._rbcnamescount < len(self._names):
try:
if self._rbcnamescount != 0:
f = repo.vfs.open(_rbcnames, 'ab')
# The position after open(x, 'a') is implementation defined-
# see issue3543. SEEK_END was added in 2.5
f.seek(0, 2) #os.SEEK_END
if f.tell() == self._rbcsnameslen:
f.write('\0')
else:
f.close()
repo.ui.debug("%s changed - rewriting it\n" % _rbcnames)
self._rbcnamescount = 0
self._rbcrevslen = 0
if self._rbcnamescount == 0:
f = repo.vfs.open(_rbcnames, 'wb')
f.write('\0'.join(encoding.fromlocal(b)
for b in self._names[self._rbcnamescount:]))
self._rbcsnameslen = f.tell()
f.close()
except (IOError, OSError, util.Abort), inst:
repo.ui.debug("couldn't write revision branch cache names: "
"%s\n" % inst)
return
self._rbcnamescount = len(self._names)
start = self._rbcrevslen * _rbcrecsize
if start != len(self._rbcrevs):
revs = min(len(repo.changelog), len(self._rbcrevs) // _rbcrecsize)
try:
f = repo.vfs.open(_rbcrevs, 'ab')
# The position after open(x, 'a') is implementation defined-
# see issue3543. SEEK_END was added in 2.5
f.seek(0, 2) #os.SEEK_END
if f.tell() != start:
repo.ui.debug("truncating %s to %s\n" % (_rbcrevs, start))
f.seek(start)
f.truncate()
end = revs * _rbcrecsize
f.write(self._rbcrevs[start:end])
f.close()
except (IOError, OSError, util.Abort), inst:
repo.ui.debug("couldn't write revision branch cache: %s\n" %
inst)
return
self._rbcrevslen = revs