branchmap: add a copy method

If we want branchcache of different filter to collaborate, they need a simple
way to copy each other. This will ensure that each filtered have no side effect
on other filter level cache.

mercurial/branchmap.py

@@ -1,212 +1,215
 # 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
 
 def _filename(repo):
     """name of a branchcache file for a given repo or repoview"""
     filename = "cache/branchheads"
     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, label = l.split(" ", 1)
             label = encoding.tolocal(label.strip())
             if not node in repo:
                 raise ValueError('node %s does not exist' % node)
             partial.setdefault(label, []).append(bin(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
 
 
 
 def updatecache(repo):
     cl = repo.changelog
     filtername = repo.filtername
     partial = repo._branchcaches.get(filtername)
 
     if partial is None or not partial.validfor(repo):
         partial = read(repo)
         if partial is None:
             partial = branchcache()
 
     revs = list(cl.revs(start=partial.tiprev +1))
     if revs:
         ctxgen = (repo[r] for r in revs)
         partial.update(repo, ctxgen)
         partial.write(repo)
     repo._branchcaches[repo.filtername] = partial
 
 class branchcache(dict):
     """A dict like object that hold branches heads cache"""
 
     def __init__(self, entries=(), tipnode=nullid, tiprev=nullrev,
                  filteredhash=None):
         super(branchcache, self).__init__(entries)
         self.tipnode = tipnode
         self.tiprev = tiprev
         self.filteredhash = filteredhash
 
     def _hashfiltered(self, repo):
         """build hash of revision filtered in the current cache
 
         Tracking tipnode and tiprev is not enough to ensure validaty 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 valide regarding a repo
 
         - False when cached tipnode are 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 copy(self):
+        """return an deep copy of the branchcache object"""
+        return branchcache(self, self.tipnode, self.tiprev, self.filteredhash)
 
     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 self.iteritems():
                 for node in nodes:
                     f.write("%s %s\n" % (hex(node), encoding.fromlocal(label)))
             f.close()
         except (IOError, OSError, util.Abort):
             # Abort may be raise by read only opener
             pass
 
     def update(self, repo, ctxgen):
         """Given a branchhead cache, self, that may have extra nodes or be
         missing heads, and a generator of nodes that are at least a superset of
         heads missing, this function updates self to be correct.
         """
         cl = repo.changelog
         # collect new branch entries
         newbranches = {}
         for c in ctxgen:
             newbranches.setdefault(c.branch(), []).append(c.node())
         # 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, newnodes in newbranches.iteritems():
             bheads = self.setdefault(branch, [])
             # Remove candidate heads that no longer are in the repo (e.g., as
             # the result of a strip that just happened).  Avoid using 'node in
             # self' here because that dives down into branchcache code somewhat
             # recursively.
             bheadrevs = [cl.rev(node) for node in bheads
                          if cl.hasnode(node)]
             newheadrevs = [cl.rev(node) for node in newnodes
                            if cl.hasnode(node)]
             ctxisnew = bheadrevs and min(newheadrevs) > max(bheadrevs)
             # Remove duplicates - nodes that are in newheadrevs and are already
             # in bheadrevs.  This can happen if you strip a node whose parent
             # was already a head (because they're on different branches).
             bheadrevs = sorted(set(bheadrevs).union(newheadrevs))
 
             # Starting from tip means fewer passes over reachable.  If we know
             # the new candidates are not ancestors of existing heads, we don't
             # have to examine ancestors of existing heads
             if ctxisnew:
                 iterrevs = sorted(newheadrevs)
             else:
                 iterrevs = list(bheadrevs)
 
             # 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 iterrevs:
                 latest = iterrevs.pop()
                 if latest not in bheadrevs:
                     continue
                 ancestors = set(cl.ancestors([latest],
                                                          bheadrevs[0]))
                 if ancestors:
                     bheadrevs = [b for b in bheadrevs if b not in ancestors]
             self[branch] = [cl.node(rev) for rev in bheadrevs]
             tiprev = max(bheadrevs)
             if tiprev > self.tiprev:
                 self.tipnode = cl.node(tiprev)
                 self.tiprev = tiprev
 
         # There may be branches that cease to exist when the last commit in the
         # branch was stripped.  This code filters them out.  Note that the
         # branch that ceased to exist may not be in newbranches because
         # newbranches is the set of candidate heads, which when you strip the
         # last commit in a branch will be the parent branch.
         droppednodes = []
         for branch in self.keys():
             nodes = [head for head in self[branch]
                      if cl.hasnode(head)]
             if not nodes:
                 droppednodes.extend(nodes)
                 del self[branch]
         if ((not self.validfor(repo)) or (self.tipnode in droppednodes)):
 
             # 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)