revbranchcache: move cache writing to the transaction finalizer

Instead of writing the revbranchcache during updatecache (which often happens
too early, before the cache is even populated), let's run it as part of the
transaction finalizer. It still won't be written for read-only operations, but
that's no worse than it is today.

A future commit will remove the actual write that happens in updatecache().

This is also good prep for when all caches get moved into the transaction.

mercurial/branchmap.py

@@ -1,459 +1,463 b''
 # branchmap.py - logic to computes, maintain and stores branchmap for local repo
 #
 # Copyright 2005-2007 Matt Mackall <[e-mail]>
 #
 # 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)
 
     if repo._revbranchcache is not None:
         repo._revbranchcache.write()
 
     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.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
 
     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 = {}
         getbranchinfo = repo.revbranchcache().branchinfo
         for r in revgen:
             branch, closesbranch = getbranchinfo(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._repo = repo
         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, rev):
         """Return branch name and close flag for rev, using and updating
         persistent cache."""
         changelog = self._repo.changelog
         rbcrevidx = rev * _rbcrecsize
 
         # if requested rev is missing, add and populate all missing revs
         if len(self._rbcrevs) < rbcrevidx + _rbcrecsize:
             self._rbcrevs.extend('\0' * (len(changelog) * _rbcrecsize -
                                          len(self._rbcrevs)))
 
         # 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 == '\0\0\0\0':
             pass
         elif cachenode == reponode:
             return self._names[branchidx], close
         else:
             # rev/node map has changed, invalidate the cache from here up
             truncate = rbcrevidx + _rbcrecsize
             del self._rbcrevs[truncate:]
             self._rbcrevslen = min(self._rbcrevslen, truncate)
 
         # fall back to slow path and make sure it will be written to disk
         return self._branchinfo(rev)
 
     def _branchinfo(self, rev):
         """Retrieve branch info from changelog and update _rbcrevs"""
         changelog = self._repo.changelog
         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
         self._setcachedata(rev, reponode, branchidx)
         return b, close
 
     def _setcachedata(self, rev, node, branchidx):
         """Writes the node's branch data to the in-memory cache data."""
         rbcrevidx = rev * _rbcrecsize
         rec = array('c')
         rec.fromstring(pack(_rbcrecfmt, node, branchidx))
         self._rbcrevs[rbcrevidx:rbcrevidx + _rbcrecsize] = rec
         self._rbcrevslen = min(self._rbcrevslen, rev)
 
-    def write(self):
+        tr = self._repo.currenttransaction()
+        if tr:
+            tr.addfinalize('write-revbranchcache', self.write)
+
+    def write(self, tr=None):
         """Save branch cache if it is dirty."""
         repo = self._repo
         if self._rbcnamescount < len(self._names):
             try:
                 if self._rbcnamescount != 0:
                     f = repo.vfs.open(_rbcnames, 'ab')
                     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')
                 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

mercurial/statichttprepo.py

@@ -1,167 +1,168 b''
 # statichttprepo.py - simple http repository class for mercurial
 #
 # This provides read-only repo access to repositories exported via static http
 #
 # Copyright 2005-2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from i18n import _
 import changelog, byterange, url, error, namespaces
 import localrepo, manifest, util, scmutil, store
 import urllib, urllib2, errno, os
 
 class httprangereader(object):
     def __init__(self, url, opener):
         # we assume opener has HTTPRangeHandler
         self.url = url
         self.pos = 0
         self.opener = opener
         self.name = url
     def seek(self, pos):
         self.pos = pos
     def read(self, bytes=None):
         req = urllib2.Request(self.url)
         end = ''
         if bytes:
             end = self.pos + bytes - 1
         if self.pos or end:
             req.add_header('Range', 'bytes=%d-%s' % (self.pos, end))
 
         try:
             f = self.opener.open(req)
             data = f.read()
             # Python 2.6+ defines a getcode() function, and 2.4 and
             # 2.5 appear to always have an undocumented code attribute
             # set. If we can't read either of those, fall back to 206
             # and hope for the best.
             code = getattr(f, 'getcode', lambda : getattr(f, 'code', 206))()
         except urllib2.HTTPError, inst:
             num = inst.code == 404 and errno.ENOENT or None
             raise IOError(num, inst)
         except urllib2.URLError, inst:
             raise IOError(None, inst.reason[1])
 
         if code == 200:
             # HTTPRangeHandler does nothing if remote does not support
             # Range headers and returns the full entity. Let's slice it.
             if bytes:
                 data = data[self.pos:self.pos + bytes]
             else:
                 data = data[self.pos:]
         elif bytes:
             data = data[:bytes]
         self.pos += len(data)
         return data
     def readlines(self):
         return self.read().splitlines(True)
     def __iter__(self):
         return iter(self.readlines())
     def close(self):
         pass
 
 def build_opener(ui, authinfo):
     # urllib cannot handle URLs with embedded user or passwd
     urlopener = url.opener(ui, authinfo)
     urlopener.add_handler(byterange.HTTPRangeHandler())
 
     class statichttpvfs(scmutil.abstractvfs):
         def __init__(self, base):
             self.base = base
 
         def __call__(self, path, mode='r', *args, **kw):
             if mode not in ('r', 'rb'):
                 raise IOError('Permission denied')
             f = "/".join((self.base, urllib.quote(path)))
             return httprangereader(f, urlopener)
 
         def join(self, path):
             if path:
                 return os.path.join(self.base, path)
             else:
                 return self.base
 
     return statichttpvfs
 
 class statichttppeer(localrepo.localpeer):
     def local(self):
         return None
     def canpush(self):
         return False
 
 class statichttprepository(localrepo.localrepository):
     supported = localrepo.localrepository._basesupported
 
     def __init__(self, ui, path):
         self._url = path
         self.ui = ui
 
         self.root = path
         u = util.url(path.rstrip('/') + "/.hg")
         self.path, authinfo = u.authinfo()
 
         opener = build_opener(ui, authinfo)
         self.opener = opener(self.path)
         self.vfs = self.opener
         self._phasedefaults = []
 
         self.names = namespaces.namespaces()
 
         try:
             requirements = scmutil.readrequires(self.vfs, self.supported)
         except IOError, inst:
             if inst.errno != errno.ENOENT:
                 raise
             requirements = set()
 
             # check if it is a non-empty old-style repository
             try:
                 fp = self.vfs("00changelog.i")
                 fp.read(1)
                 fp.close()
             except IOError, inst:
                 if inst.errno != errno.ENOENT:
                     raise
                 # we do not care about empty old-style repositories here
                 msg = _("'%s' does not appear to be an hg repository") % path
                 raise error.RepoError(msg)
 
         # setup store
         self.store = store.store(requirements, self.path, opener)
         self.spath = self.store.path
         self.svfs = self.store.opener
         self.sopener = self.svfs
         self.sjoin = self.store.join
         self._filecache = {}
         self.requirements = requirements
 
         self.manifest = manifest.manifest(self.svfs)
         self.changelog = changelog.changelog(self.svfs)
         self._tags = None
         self.nodetagscache = None
         self._branchcaches = {}
         self._revbranchcache = None
         self.encodepats = None
         self.decodepats = None
+        self._transref = None
 
     def _restrictcapabilities(self, caps):
         caps = super(statichttprepository, self)._restrictcapabilities(caps)
         return caps.difference(["pushkey"])
 
     def url(self):
         return self._url
 
     def local(self):
         return False
 
     def peer(self):
         return statichttppeer(self)
 
     def lock(self, wait=True):
         raise util.Abort(_('cannot lock static-http repository'))
 
 def instance(ui, path, create):
     if create:
         raise util.Abort(_('cannot create new static-http repository'))
     return statichttprepository(ui, path[7:])