Optimizing manifest reads in changegroupsubset by using deltas.

mercurial/localrepo.py

@@ -1,1569 +1,1585
 # localrepo.py - read/write repository class for mercurial
 #
 # Copyright 2005 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
 import struct, os, util
 import filelog, manifest, changelog, dirstate, repo
 from node import *
 from demandload import *
 demandload(globals(), "re lock transaction tempfile stat mdiff errno")
 
 class localrepository:
     def __init__(self, ui, path=None, create=0):
         if not path:
             p = os.getcwd()
             while not os.path.isdir(os.path.join(p, ".hg")):
                 oldp = p
                 p = os.path.dirname(p)
                 if p == oldp: raise repo.RepoError("no repo found")
             path = p
         self.path = os.path.join(path, ".hg")
 
         if not create and not os.path.isdir(self.path):
             raise repo.RepoError("repository %s not found" % self.path)
 
         self.root = os.path.abspath(path)
         self.ui = ui
         self.opener = util.opener(self.path)
         self.wopener = util.opener(self.root)
         self.manifest = manifest.manifest(self.opener)
         self.changelog = changelog.changelog(self.opener)
         self.tagscache = None
         self.nodetagscache = None
         self.encodepats = None
         self.decodepats = None
 
         if create:
             os.mkdir(self.path)
             os.mkdir(self.join("data"))
 
         self.dirstate = dirstate.dirstate(self.opener, ui, self.root)
         try:
             self.ui.readconfig(self.opener("hgrc"))
         except IOError: pass
 
     def hook(self, name, **args):
         s = self.ui.config("hooks", name)
         if s:
             self.ui.note("running hook %s: %s\n" % (name, s))
             old = {}
             for k, v in args.items():
                 k = k.upper()
                 old[k] = os.environ.get(k, None)
                 os.environ[k] = v
 
             # Hooks run in the repository root
             olddir = os.getcwd()
             os.chdir(self.root)
             r = os.system(s)
             os.chdir(olddir)
 
             for k, v in old.items():
                 if v != None:
                     os.environ[k] = v
                 else:
                     del os.environ[k]
 
             if r:
                 self.ui.warn("abort: %s hook failed with status %d!\n" %
                              (name, r))
                 return False
         return True
 
     def tags(self):
         '''return a mapping of tag to node'''
         if not self.tagscache:
             self.tagscache = {}
             def addtag(self, k, n):
                 try:
                     bin_n = bin(n)
                 except TypeError:
                     bin_n = ''
                 self.tagscache[k.strip()] = bin_n
 
             try:
                 # read each head of the tags file, ending with the tip
                 # and add each tag found to the map, with "newer" ones
                 # taking precedence
                 fl = self.file(".hgtags")
                 h = fl.heads()
                 h.reverse()
                 for r in h:
                     for l in fl.read(r).splitlines():
                         if l:
                             n, k = l.split(" ", 1)
                             addtag(self, k, n)
             except KeyError:
                 pass
 
             try:
                 f = self.opener("localtags")
                 for l in f:
                     n, k = l.split(" ", 1)
                     addtag(self, k, n)
             except IOError:
                 pass
 
             self.tagscache['tip'] = self.changelog.tip()
 
         return self.tagscache
 
     def tagslist(self):
         '''return a list of tags ordered by revision'''
         l = []
         for t, n in self.tags().items():
             try:
                 r = self.changelog.rev(n)
             except:
                 r = -2 # sort to the beginning of the list if unknown
             l.append((r,t,n))
         l.sort()
         return [(t,n) for r,t,n in l]
 
     def nodetags(self, node):
         '''return the tags associated with a node'''
         if not self.nodetagscache:
             self.nodetagscache = {}
             for t,n in self.tags().items():
                 self.nodetagscache.setdefault(n,[]).append(t)
         return self.nodetagscache.get(node, [])
 
     def lookup(self, key):
         try:
             return self.tags()[key]
         except KeyError:
             try:
                 return self.changelog.lookup(key)
             except:
                 raise repo.RepoError("unknown revision '%s'" % key)
 
     def dev(self):
         return os.stat(self.path).st_dev
 
     def local(self):
         return True
 
     def join(self, f):
         return os.path.join(self.path, f)
 
     def wjoin(self, f):
         return os.path.join(self.root, f)
 
     def file(self, f):
         if f[0] == '/': f = f[1:]
         return filelog.filelog(self.opener, f)
 
     def getcwd(self):
         return self.dirstate.getcwd()
 
     def wfile(self, f, mode='r'):
         return self.wopener(f, mode)
 
     def wread(self, filename):
         if self.encodepats == None:
             l = []
             for pat, cmd in self.ui.configitems("encode"):
                 mf = util.matcher("", "/", [pat], [], [])[1]
                 l.append((mf, cmd))
             self.encodepats = l
 
         data = self.wopener(filename, 'r').read()
 
         for mf, cmd in self.encodepats:
             if mf(filename):
                 self.ui.debug("filtering %s through %s\n" % (filename, cmd))
                 data = util.filter(data, cmd)
                 break
 
         return data
 
     def wwrite(self, filename, data, fd=None):
         if self.decodepats == None:
             l = []
             for pat, cmd in self.ui.configitems("decode"):
                 mf = util.matcher("", "/", [pat], [], [])[1]
                 l.append((mf, cmd))
             self.decodepats = l
 
         for mf, cmd in self.decodepats:
             if mf(filename):
                 self.ui.debug("filtering %s through %s\n" % (filename, cmd))
                 data = util.filter(data, cmd)
                 break
 
         if fd:
             return fd.write(data)
         return self.wopener(filename, 'w').write(data)
 
     def transaction(self):
         # save dirstate for undo
         try:
             ds = self.opener("dirstate").read()
         except IOError:
             ds = ""
         self.opener("journal.dirstate", "w").write(ds)
 
         def after():
             util.rename(self.join("journal"), self.join("undo"))
             util.rename(self.join("journal.dirstate"),
                         self.join("undo.dirstate"))
 
         return transaction.transaction(self.ui.warn, self.opener,
                                        self.join("journal"), after)
 
     def recover(self):
         lock = self.lock()
         if os.path.exists(self.join("journal")):
             self.ui.status("rolling back interrupted transaction\n")
             return transaction.rollback(self.opener, self.join("journal"))
         else:
             self.ui.warn("no interrupted transaction available\n")
 
     def undo(self):
         lock = self.lock()
         if os.path.exists(self.join("undo")):
             self.ui.status("rolling back last transaction\n")
             transaction.rollback(self.opener, self.join("undo"))
             self.dirstate = None
             util.rename(self.join("undo.dirstate"), self.join("dirstate"))
             self.dirstate = dirstate.dirstate(self.opener, self.ui, self.root)
         else:
             self.ui.warn("no undo information available\n")
 
     def lock(self, wait=1):
         try:
             return lock.lock(self.join("lock"), 0)
         except lock.LockHeld, inst:
             if wait:
                 self.ui.warn("waiting for lock held by %s\n" % inst.args[0])
                 return lock.lock(self.join("lock"), wait)
             raise inst
 
     def rawcommit(self, files, text, user, date, p1=None, p2=None):
         orig_parent = self.dirstate.parents()[0] or nullid
         p1 = p1 or self.dirstate.parents()[0] or nullid
         p2 = p2 or self.dirstate.parents()[1] or nullid
         c1 = self.changelog.read(p1)
         c2 = self.changelog.read(p2)
         m1 = self.manifest.read(c1[0])
         mf1 = self.manifest.readflags(c1[0])
         m2 = self.manifest.read(c2[0])
         changed = []
 
         if orig_parent == p1:
             update_dirstate = 1
         else:
             update_dirstate = 0
 
         tr = self.transaction()
         mm = m1.copy()
         mfm = mf1.copy()
         linkrev = self.changelog.count()
         for f in files:
             try:
                 t = self.wread(f)
                 tm = util.is_exec(self.wjoin(f), mfm.get(f, False))
                 r = self.file(f)
                 mfm[f] = tm
 
                 fp1 = m1.get(f, nullid)
                 fp2 = m2.get(f, nullid)
 
                 # is the same revision on two branches of a merge?
                 if fp2 == fp1:
                     fp2 = nullid
 
                 if fp2 != nullid:
                     # is one parent an ancestor of the other?
                     fpa = r.ancestor(fp1, fp2)
                     if fpa == fp1:
                         fp1, fp2 = fp2, nullid
                     elif fpa == fp2:
                         fp2 = nullid
 
                     # is the file unmodified from the parent?
                     if t == r.read(fp1):
                         # record the proper existing parent in manifest
                         # no need to add a revision
                         mm[f] = fp1
                         continue
 
                 mm[f] = r.add(t, {}, tr, linkrev, fp1, fp2)
                 changed.append(f)
                 if update_dirstate:
                     self.dirstate.update([f], "n")
             except IOError:
                 try:
                     del mm[f]
                     del mfm[f]
                     if update_dirstate:
                         self.dirstate.forget([f])
                 except:
                     # deleted from p2?
                     pass
 
         mnode = self.manifest.add(mm, mfm, tr, linkrev, c1[0], c2[0])
         user = user or self.ui.username()
         n = self.changelog.add(mnode, changed, text, tr, p1, p2, user, date)
         tr.close()
         if update_dirstate:
             self.dirstate.setparents(n, nullid)
 
     def commit(self, files = None, text = "", user = None, date = None,
                match = util.always, force=False):
         commit = []
         remove = []
         changed = []
 
         if files:
             for f in files:
                 s = self.dirstate.state(f)
                 if s in 'nmai':
                     commit.append(f)
                 elif s == 'r':
                     remove.append(f)
                 else:
                     self.ui.warn("%s not tracked!\n" % f)
         else:
             (c, a, d, u) = self.changes(match=match)
             commit = c + a
             remove = d
 
         p1, p2 = self.dirstate.parents()
         c1 = self.changelog.read(p1)
         c2 = self.changelog.read(p2)
         m1 = self.manifest.read(c1[0])
         mf1 = self.manifest.readflags(c1[0])
         m2 = self.manifest.read(c2[0])
 
         if not commit and not remove and not force and p2 == nullid:
             self.ui.status("nothing changed\n")
             return None
 
         if not self.hook("precommit"):
             return None
 
         lock = self.lock()
         tr = self.transaction()
 
         # check in files
         new = {}
         linkrev = self.changelog.count()
         commit.sort()
         for f in commit:
             self.ui.note(f + "\n")
             try:
                 mf1[f] = util.is_exec(self.wjoin(f), mf1.get(f, False))
                 t = self.wread(f)
             except IOError:
                 self.ui.warn("trouble committing %s!\n" % f)
                 raise
 
             r = self.file(f)
 
             meta = {}
             cp = self.dirstate.copied(f)
             if cp:
                 meta["copy"] = cp
                 meta["copyrev"] = hex(m1.get(cp, m2.get(cp, nullid)))
                 self.ui.debug(" %s: copy %s:%s\n" % (f, cp, meta["copyrev"]))
                 fp1, fp2 = nullid, nullid
             else:
                 fp1 = m1.get(f, nullid)
                 fp2 = m2.get(f, nullid)
 
             # is the same revision on two branches of a merge?
             if fp2 == fp1:
                 fp2 = nullid
 
             if fp2 != nullid:
                 # is one parent an ancestor of the other?
                 fpa = r.ancestor(fp1, fp2)
                 if fpa == fp1:
                     fp1, fp2 = fp2, nullid
                 elif fpa == fp2:
                     fp2 = nullid
 
                 # is the file unmodified from the parent?
                 if not meta and t == r.read(fp1):
                     # record the proper existing parent in manifest
                     # no need to add a revision
                     new[f] = fp1
                     continue
 
             new[f] = r.add(t, meta, tr, linkrev, fp1, fp2)
             # remember what we've added so that we can later calculate
             # the files to pull from a set of changesets
             changed.append(f)
 
         # update manifest
         m1.update(new)
         for f in remove:
             if f in m1:
                 del m1[f]
         mn = self.manifest.add(m1, mf1, tr, linkrev, c1[0], c2[0],
                                (new, remove))
 
         # add changeset
         new = new.keys()
         new.sort()
 
         if not text:
             edittext = ""
             if p2 != nullid:
                 edittext += "HG: branch merge\n"
             edittext += "\n" + "HG: manifest hash %s\n" % hex(mn)
             edittext += "".join(["HG: changed %s\n" % f for f in changed])
             edittext += "".join(["HG: removed %s\n" % f for f in remove])
             if not changed and not remove:
                 edittext += "HG: no files changed\n"
             edittext = self.ui.edit(edittext)
             if not edittext.rstrip():
                 return None
             text = edittext
 
         user = user or self.ui.username()
         n = self.changelog.add(mn, changed, text, tr, p1, p2, user, date)
         tr.close()
 
         self.dirstate.setparents(n)
         self.dirstate.update(new, "n")
         self.dirstate.forget(remove)
 
         if not self.hook("commit", node=hex(n)):
             return None
         return n
 
     def walk(self, node=None, files=[], match=util.always):
         if node:
             for fn in self.manifest.read(self.changelog.read(node)[0]):
                 if match(fn): yield 'm', fn
         else:
             for src, fn in self.dirstate.walk(files, match):
                 yield src, fn
 
     def changes(self, node1 = None, node2 = None, files = [],
                 match = util.always):
         mf2, u = None, []
 
         def fcmp(fn, mf):
             t1 = self.wread(fn)
             t2 = self.file(fn).read(mf.get(fn, nullid))
             return cmp(t1, t2)
 
         def mfmatches(node):
             mf = dict(self.manifest.read(node))
             for fn in mf.keys():
                 if not match(fn):
                     del mf[fn]
             return mf
 
         # are we comparing the working directory?
         if not node2:
             l, c, a, d, u = self.dirstate.changes(files, match)
 
             # are we comparing working dir against its parent?
             if not node1:
                 if l:
                     # do a full compare of any files that might have changed
                     change = self.changelog.read(self.dirstate.parents()[0])
                     mf2 = mfmatches(change[0])
                     for f in l:
                         if fcmp(f, mf2):
                             c.append(f)
 
                 for l in c, a, d, u:
                     l.sort()
 
                 return (c, a, d, u)
 
         # are we comparing working dir against non-tip?
         # generate a pseudo-manifest for the working dir
         if not node2:
             if not mf2:
                 change = self.changelog.read(self.dirstate.parents()[0])
                 mf2 = mfmatches(change[0])
             for f in a + c + l:
                 mf2[f] = ""
             for f in d:
                 if f in mf2: del mf2[f]
         else:
             change = self.changelog.read(node2)
             mf2 = mfmatches(change[0])
 
         # flush lists from dirstate before comparing manifests
         c, a = [], []
 
         change = self.changelog.read(node1)
         mf1 = mfmatches(change[0])
 
         for fn in mf2:
             if mf1.has_key(fn):
                 if mf1[fn] != mf2[fn]:
                     if mf2[fn] != "" or fcmp(fn, mf1):
                         c.append(fn)
                 del mf1[fn]
             else:
                 a.append(fn)
 
         d = mf1.keys()
 
         for l in c, a, d, u:
             l.sort()
 
         return (c, a, d, u)
 
     def add(self, list):
         for f in list:
             p = self.wjoin(f)
             if not os.path.exists(p):
                 self.ui.warn("%s does not exist!\n" % f)
             elif not os.path.isfile(p):
                 self.ui.warn("%s not added: only files supported currently\n" % f)
             elif self.dirstate.state(f) in 'an':
                 self.ui.warn("%s already tracked!\n" % f)
             else:
                 self.dirstate.update([f], "a")
 
     def forget(self, list):
         for f in list:
             if self.dirstate.state(f) not in 'ai':
                 self.ui.warn("%s not added!\n" % f)
             else:
                 self.dirstate.forget([f])
 
     def remove(self, list):
         for f in list:
             p = self.wjoin(f)
             if os.path.exists(p):
                 self.ui.warn("%s still exists!\n" % f)
             elif self.dirstate.state(f) == 'a':
                 self.ui.warn("%s never committed!\n" % f)
                 self.dirstate.forget([f])
             elif f not in self.dirstate:
                 self.ui.warn("%s not tracked!\n" % f)
             else:
                 self.dirstate.update([f], "r")
 
     def copy(self, source, dest):
         p = self.wjoin(dest)
         if not os.path.exists(p):
             self.ui.warn("%s does not exist!\n" % dest)
         elif not os.path.isfile(p):
             self.ui.warn("copy failed: %s is not a file\n" % dest)
         else:
             if self.dirstate.state(dest) == '?':
                 self.dirstate.update([dest], "a")
             self.dirstate.copy(source, dest)
 
     def heads(self):
         return self.changelog.heads()
 
     # branchlookup returns a dict giving a list of branches for
     # each head.  A branch is defined as the tag of a node or
     # the branch of the node's parents.  If a node has multiple
     # branch tags, tags are eliminated if they are visible from other
     # branch tags.
     #
     # So, for this graph:  a->b->c->d->e
     #                       \         /
     #                        aa -----/
     # a has tag 2.6.12
     # d has tag 2.6.13
     # e would have branch tags for 2.6.12 and 2.6.13.  Because the node
     # for 2.6.12 can be reached from the node 2.6.13, that is eliminated
     # from the list.
     #
     # It is possible that more than one head will have the same branch tag.
     # callers need to check the result for multiple heads under the same
     # branch tag if that is a problem for them (ie checkout of a specific
     # branch).
     #
     # passing in a specific branch will limit the depth of the search
     # through the parents.  It won't limit the branches returned in the
     # result though.
     def branchlookup(self, heads=None, branch=None):
         if not heads:
             heads = self.heads()
         headt = [ h for h in heads ]
         chlog = self.changelog
         branches = {}
         merges = []
         seenmerge = {}
 
         # traverse the tree once for each head, recording in the branches
         # dict which tags are visible from this head.  The branches
         # dict also records which tags are visible from each tag
         # while we traverse.
         while headt or merges:
             if merges:
                 n, found = merges.pop()
                 visit = [n]
             else:
                 h = headt.pop()
                 visit = [h]
                 found = [h]
                 seen = {}
             while visit:
                 n = visit.pop()
                 if n in seen:
                     continue
                 pp = chlog.parents(n)
                 tags = self.nodetags(n)
                 if tags:
                     for x in tags:
                         if x == 'tip':
                             continue
                         for f in found:
                             branches.setdefault(f, {})[n] = 1
                         branches.setdefault(n, {})[n] = 1
                         break
                     if n not in found:
                         found.append(n)
                     if branch in tags:
                         continue
                 seen[n] = 1
                 if pp[1] != nullid and n not in seenmerge:
                     merges.append((pp[1], [x for x in found]))
                     seenmerge[n] = 1
                 if pp[0] != nullid:
                     visit.append(pp[0])
         # traverse the branches dict, eliminating branch tags from each
         # head that are visible from another branch tag for that head.
         out = {}
         viscache = {}
         for h in heads:
             def visible(node):
                 if node in viscache:
                     return viscache[node]
                 ret = {}
                 visit = [node]
                 while visit:
                     x = visit.pop()
                     if x in viscache:
                         ret.update(viscache[x])
                     elif x not in ret:
                         ret[x] = 1
                         if x in branches:
                             visit[len(visit):] = branches[x].keys()
                 viscache[node] = ret
                 return ret
             if h not in branches:
                 continue
             # O(n^2), but somewhat limited.  This only searches the
             # tags visible from a specific head, not all the tags in the
             # whole repo.
             for b in branches[h]:
                 vis = False
                 for bb in branches[h].keys():
                     if b != bb:
                         if b in visible(bb):
                             vis = True
                             break
                 if not vis:
                     l = out.setdefault(h, [])
                     l[len(l):] = self.nodetags(b)
         return out
 
     def branches(self, nodes):
         if not nodes: nodes = [self.changelog.tip()]
         b = []
         for n in nodes:
             t = n
             while n:
                 p = self.changelog.parents(n)
                 if p[1] != nullid or p[0] == nullid:
                     b.append((t, n, p[0], p[1]))
                     break
                 n = p[0]
         return b
 
     def between(self, pairs):
         r = []
 
         for top, bottom in pairs:
             n, l, i = top, [], 0
             f = 1
 
             while n != bottom:
                 p = self.changelog.parents(n)[0]
                 if i == f:
                     l.append(n)
                     f = f * 2
                 n = p
                 i += 1
 
             r.append(l)
 
         return r
 
     def findincoming(self, remote, base=None, heads=None):
         m = self.changelog.nodemap
         search = []
         fetch = {}
         seen = {}
         seenbranch = {}
         if base == None:
             base = {}
 
         # assume we're closer to the tip than the root
         # and start by examining the heads
         self.ui.status("searching for changes\n")
 
         if not heads:
             heads = remote.heads()
 
         unknown = []
         for h in heads:
             if h not in m:
                 unknown.append(h)
             else:
                 base[h] = 1
 
         if not unknown:
             return None
 
         rep = {}
         reqcnt = 0
 
         # search through remote branches
         # a 'branch' here is a linear segment of history, with four parts:
         # head, root, first parent, second parent
         # (a branch always has two parents (or none) by definition)
         unknown = remote.branches(unknown)
         while unknown:
             r = []
             while unknown:
                 n = unknown.pop(0)
                 if n[0] in seen:
                     continue
 
                 self.ui.debug("examining %s:%s\n" % (short(n[0]), short(n[1])))
                 if n[0] == nullid:
                     break
                 if n in seenbranch:
                     self.ui.debug("branch already found\n")
                     continue
                 if n[1] and n[1] in m: # do we know the base?
                     self.ui.debug("found incomplete branch %s:%s\n"
                                   % (short(n[0]), short(n[1])))
                     search.append(n) # schedule branch range for scanning
                     seenbranch[n] = 1
                 else:
                     if n[1] not in seen and n[1] not in fetch:
                         if n[2] in m and n[3] in m:
                             self.ui.debug("found new changeset %s\n" %
                                           short(n[1]))
                             fetch[n[1]] = 1 # earliest unknown
                             base[n[2]] = 1 # latest known
                             continue
 
                     for a in n[2:4]:
                         if a not in rep:
                             r.append(a)
                             rep[a] = 1
 
                 seen[n[0]] = 1
 
             if r:
                 reqcnt += 1
                 self.ui.debug("request %d: %s\n" %
                             (reqcnt, " ".join(map(short, r))))
                 for p in range(0, len(r), 10):
                     for b in remote.branches(r[p:p+10]):
                         self.ui.debug("received %s:%s\n" %
                                       (short(b[0]), short(b[1])))
                         if b[0] in m:
                             self.ui.debug("found base node %s\n" % short(b[0]))
                             base[b[0]] = 1
                         elif b[0] not in seen:
                             unknown.append(b)
 
         # do binary search on the branches we found
         while search:
             n = search.pop(0)
             reqcnt += 1
             l = remote.between([(n[0], n[1])])[0]
             l.append(n[1])
             p = n[0]
             f = 1
             for i in l:
                 self.ui.debug("narrowing %d:%d %s\n" % (f, len(l), short(i)))
                 if i in m:
                     if f <= 2:
                         self.ui.debug("found new branch changeset %s\n" %
                                           short(p))
                         fetch[p] = 1
                         base[i] = 1
                     else:
                         self.ui.debug("narrowed branch search to %s:%s\n"
                                       % (short(p), short(i)))
                         search.append((p, i))
                     break
                 p, f = i, f * 2
 
         # sanity check our fetch list
         for f in fetch.keys():
             if f in m:
                 raise repo.RepoError("already have changeset " + short(f[:4]))
 
         if base.keys() == [nullid]:
             self.ui.warn("warning: pulling from an unrelated repository!\n")
 
         self.ui.note("found new changesets starting at " +
                      " ".join([short(f) for f in fetch]) + "\n")
 
         self.ui.debug("%d total queries\n" % reqcnt)
 
         return fetch.keys()
 
     def findoutgoing(self, remote, base=None, heads=None):
         if base == None:
             base = {}
             self.findincoming(remote, base, heads)
 
         self.ui.debug("common changesets up to "
                       + " ".join(map(short, base.keys())) + "\n")
 
         remain = dict.fromkeys(self.changelog.nodemap)
 
         # prune everything remote has from the tree
         del remain[nullid]
         remove = base.keys()
         while remove:
             n = remove.pop(0)
             if n in remain:
                 del remain[n]
                 for p in self.changelog.parents(n):
                     remove.append(p)
 
         # find every node whose parents have been pruned
         subset = []
         for n in remain:
             p1, p2 = self.changelog.parents(n)
             if p1 not in remain and p2 not in remain:
                 subset.append(n)
 
         # this is the set of all roots we have to push
         return subset
 
     def pull(self, remote, heads = None):
         lock = self.lock()
 
         # if we have an empty repo, fetch everything
         if self.changelog.tip() == nullid:
             self.ui.status("requesting all changes\n")
             fetch = [nullid]
         else:
             fetch = self.findincoming(remote)
 
         if not fetch:
             self.ui.status("no changes found\n")
             return 1
 
         if heads is None:
             cg = remote.changegroup(fetch)
         else:
             cg = remote.changegroupsubset(fetch, heads)
         return self.addchangegroup(cg)
 
     def push(self, remote, force=False):
         lock = remote.lock()
 
         base = {}
         heads = remote.heads()
         inc = self.findincoming(remote, base, heads)
         if not force and inc:
             self.ui.warn("abort: unsynced remote changes!\n")
             self.ui.status("(did you forget to sync? use push -f to force)\n")
             return 1
 
         update = self.findoutgoing(remote, base)
         if not update:
             self.ui.status("no changes found\n")
             return 1
         elif not force:
             if len(heads) < len(self.changelog.heads()):
                 self.ui.warn("abort: push creates new remote branches!\n")
                 self.ui.status("(did you forget to merge?" +
                                " use push -f to force)\n")
                 return 1
 
         cg = self.changegroup(update)
         return remote.addchangegroup(cg)
 
     def changegroupsubset(self, bases, heads):
         cl = self.changelog
         # msng = missing
         msng_cl_lst, bases, heads = cl.nodesbetween(bases, heads)
         junk = None
         knownheads = {}
         for n in bases:
             for p in cl.parents(n):
                 if p != nullid:
                     knownheads[p] = 1
         knownheads = knownheads.keys()
         if knownheads:
             has_cl_set, junk, junk = cl.nodesbetween(None, knownheads)
             has_cl_set = dict.fromkeys(hasnodeset)
         else:
             has_cl_set = {}
 
         mnfst = self.manifest
         msng_mnfst_set = {}
         msng_filenode_set = {}
 
         junk = mnfst.index[mnfst.count() - 1] # Get around a bug in lazyindex
         junk = None
 
         def identity(x):
             return x
 
         def cmp_by_rev_func(revlog):
             def cmpfunc(a, b):
                 return cmp(revlog.rev(a), revlog.rev(b))
             return cmpfunc
 
         def prune_parents(revlog, hasset, msngset):
             haslst = hasset.keys()
             haslst.sort(cmp_by_rev_func(revlog))
             for node in haslst:
                 parentlst = [p for p in revlog.parents(node) if p != nullid]
                 while parentlst:
                     n = parentlst.pop()
                     if n not in hasset:
                         hasset[n] = 1
                         p = [p for p in revlog.parents(n) if p != nullid]
                         parentlst.extend(p)
             for n in hasset:
                 msngset.pop(n, None)
 
         def manifest_and_file_collector(changedfileset):
             def collect_manifests_and_files(clnode):
                 c = cl.read(clnode)
                 for f in c[3]:
                     # This is to make sure we only have one instance of each
                     # filename string for each filename.
                     changedfileset.setdefault(f, f)
                 msng_mnfst_set.setdefault(c[0], clnode)
             return collect_manifests_and_files
 
         def prune_manifests():
             has_mnfst_set = {}
             for n in msng_mnfst_set:
                 linknode = cl.node(mnfst.linkrev(n))
                 if linknode in has_cl_set:
                     has_mnfst_set[n] = 1
             prune_parents(mnfst, has_mnfst_set, msng_mnfst_set)
 
         def lookup_manifest_link(mnfstnode):
             return msng_mnfst_set[mnfstnode]
 
         def filenode_collector(changedfiles):
+            next_rev = [0]
             def collect_msng_filenodes(mnfstnode):
-                m = mnfst.read(mnfstnode)
-                for f in changedfiles:
-                    fnode = m.get(f, None)
-                    if fnode is not None:
-                        clnode = msng_mnfst_set[mnfstnode]
-                        ndset = msng_filenode_set.setdefault(f, {})
-                        ndset.setdefault(fnode, clnode)
+                r = mnfst.rev(mnfstnode)
+                if r == next_rev[0]:
+                    # If the last rev we looked at was the one just previous,
+                    # we only need to see a diff.
+                    delta = mdiff.patchtext(mnfst.delta(mnfstnode))
+                    for dline in delta.splitlines():
+                        f, fnode = dline.split('\0')
+                        fnode = bin(fnode[:40])
+                        f = changedfiles.get(f, None)
+                        if f is not None:
+                            clnode = msng_mnfst_set[mnfstnode]
+                            ndset = msng_filenode_set.setdefault(f, {})
+                            ndset.setdefault(fnode, clnode)
+                else:
+                    m = mnfst.read(mnfstnode)
+                    for f in changedfiles:
+                        fnode = m.get(f, None)
+                        if fnode is not None:
+                            clnode = msng_mnfst_set[mnfstnode]
+                            ndset = msng_filenode_set.setdefault(f, {})
+                            ndset.setdefault(fnode, clnode)
+                next_rev[0] = r + 1
             return collect_msng_filenodes
 
         def prune_filenodes(f, filerevlog):
             msngset = msng_filenode_set[f]
             hasset = {}
             for n in msngset:
                 clnode = cl.node(filerevlog.linkrev(n))
                 if clnode in has_cl_set:
                     hasset[n] = 1
             prune_parents(filerevlog, hasset, msngset)
 
         def lookup_filenode_link_func(fname):
             msngset = msng_filenode_set[fname]
             def lookup_filenode_link(fnode):
                 return msngset[fnode]
             return lookup_filenode_link
 
         def gengroup():
             changedfiles = {}
             group = cl.group(msng_cl_lst, identity,
                              manifest_and_file_collector(changedfiles))
             for chnk in group:
                 yield chnk
             prune_manifests()
             msng_mnfst_lst = msng_mnfst_set.keys()
             msng_mnfst_lst.sort(cmp_by_rev_func(mnfst))
-            changedfiles = changedfiles.keys()
-            changedfiles.sort()
             group = mnfst.group(msng_mnfst_lst, lookup_manifest_link,
                                 filenode_collector(changedfiles))
             for chnk in group:
                 yield chnk
             msng_mnfst_lst = None
             msng_mnfst_set.clear()
+            changedfiles = changedfiles.keys()
+            changedfiles.sort()
             for fname in changedfiles:
                 filerevlog = self.file(fname)
                 prune_filenodes(fname, filerevlog)
                 msng_filenode_lst = msng_filenode_set[fname].keys()
                 if len(msng_filenode_lst) > 0:
                     yield struct.pack(">l", len(fname) + 4) + fname
                     msng_filenode_lst.sort(cmp_by_rev_func(filerevlog))
                     group = filerevlog.group(msng_filenode_lst,
                                              lookup_filenode_link_func(fname))
                     for chnk in group:
                         yield chnk
                 del msng_filenode_set[fname]
             yield struct.pack(">l", 0)
 
         return util.chunkbuffer(gengroup())
 
     def changegroup(self, basenodes):
         cl = self.changelog
         nodes = cl.nodesbetween(basenodes, None)[0]
         revset = dict.fromkeys([cl.rev(n) for n in nodes])
 
         def identity(x):
             return x
 
         def gennodelst(revlog):
             for r in xrange(0, revlog.count()):
                 n = revlog.node(r)
                 if revlog.linkrev(n) in revset:
                     yield n
 
         def changed_file_collector(changedfileset):
             def collect_changed_files(clnode):
                 c = cl.read(clnode)
                 for fname in c[3]:
                     changedfileset[fname] = 1
             return collect_changed_files
 
         def lookuprevlink_func(revlog):
             def lookuprevlink(n):
                 return cl.node(revlog.linkrev(n))
             return lookuprevlink
 
         def gengroup():
             # construct a list of all changed files
             changedfiles = {}
 
             for chnk in cl.group(nodes, identity,
                                  changed_file_collector(changedfiles)):
                 yield chnk
             changedfiles = changedfiles.keys()
             changedfiles.sort()
 
             mnfst = self.manifest
             nodeiter = gennodelst(mnfst)
             for chnk in mnfst.group(nodeiter, lookuprevlink_func(mnfst)):
                 yield chnk
 
             for fname in changedfiles:
                 filerevlog = self.file(fname)
                 nodeiter = gennodelst(filerevlog)
                 nodeiter = list(nodeiter)
                 if nodeiter:
                     yield struct.pack(">l", len(fname) + 4) + fname
                     lookup = lookuprevlink_func(filerevlog)
                     for chnk in filerevlog.group(nodeiter, lookup):
                         yield chnk
 
             yield struct.pack(">l", 0)
 
         return util.chunkbuffer(gengroup())
 
     def addchangegroup(self, source):
 
         def getchunk():
             d = source.read(4)
             if not d: return ""
             l = struct.unpack(">l", d)[0]
             if l <= 4: return ""
             d = source.read(l - 4)
             if len(d) < l - 4:
                 raise repo.RepoError("premature EOF reading chunk" +
                                      " (got %d bytes, expected %d)"
                                      % (len(d), l - 4))
             return d
 
         def getgroup():
             while 1:
                 c = getchunk()
                 if not c: break
                 yield c
 
         def csmap(x):
             self.ui.debug("add changeset %s\n" % short(x))
             return self.changelog.count()
 
         def revmap(x):
             return self.changelog.rev(x)
 
         if not source: return
         changesets = files = revisions = 0
 
         tr = self.transaction()
 
         oldheads = len(self.changelog.heads())
 
         # pull off the changeset group
         self.ui.status("adding changesets\n")
         co = self.changelog.tip()
         cn = self.changelog.addgroup(getgroup(), csmap, tr, 1) # unique
         cnr, cor = map(self.changelog.rev, (cn, co))
         if cn == nullid:
             cnr = cor
         changesets = cnr - cor
 
         # pull off the manifest group
         self.ui.status("adding manifests\n")
         mm = self.manifest.tip()
         mo = self.manifest.addgroup(getgroup(), revmap, tr)
 
         # process the files
         self.ui.status("adding file changes\n")
         while 1:
             f = getchunk()
             if not f: break
             self.ui.debug("adding %s revisions\n" % f)
             fl = self.file(f)
             o = fl.count()
             n = fl.addgroup(getgroup(), revmap, tr)
             revisions += fl.count() - o
             files += 1
 
         newheads = len(self.changelog.heads())
         heads = ""
         if oldheads and newheads > oldheads:
             heads = " (+%d heads)" % (newheads - oldheads)
 
         self.ui.status(("added %d changesets" +
                         " with %d changes to %d files%s\n")
                        % (changesets, revisions, files, heads))
 
         tr.close()
 
         if changesets > 0:
             if not self.hook("changegroup",
                               node=hex(self.changelog.node(cor+1))):
                 self.ui.warn("abort: changegroup hook returned failure!\n")
                 return 1
 
             for i in range(cor + 1, cnr + 1):
                 self.hook("commit", node=hex(self.changelog.node(i)))
 
         return
 
     def update(self, node, allow=False, force=False, choose=None,
                moddirstate=True):
         pl = self.dirstate.parents()
         if not force and pl[1] != nullid:
             self.ui.warn("aborting: outstanding uncommitted merges\n")
             return 1
 
         p1, p2 = pl[0], node
         pa = self.changelog.ancestor(p1, p2)
         m1n = self.changelog.read(p1)[0]
         m2n = self.changelog.read(p2)[0]
         man = self.manifest.ancestor(m1n, m2n)
         m1 = self.manifest.read(m1n)
         mf1 = self.manifest.readflags(m1n)
         m2 = self.manifest.read(m2n)
         mf2 = self.manifest.readflags(m2n)
         ma = self.manifest.read(man)
         mfa = self.manifest.readflags(man)
 
         (c, a, d, u) = self.changes()
 
         # is this a jump, or a merge?  i.e. is there a linear path
         # from p1 to p2?
         linear_path = (pa == p1 or pa == p2)
 
         # resolve the manifest to determine which files
         # we care about merging
         self.ui.note("resolving manifests\n")
         self.ui.debug(" force %s allow %s moddirstate %s linear %s\n" %
                       (force, allow, moddirstate, linear_path))
         self.ui.debug(" ancestor %s local %s remote %s\n" %
                       (short(man), short(m1n), short(m2n)))
 
         merge = {}
         get = {}
         remove = []
 
         # construct a working dir manifest
         mw = m1.copy()
         mfw = mf1.copy()
         umap = dict.fromkeys(u)
 
         for f in a + c + u:
             mw[f] = ""
             mfw[f] = util.is_exec(self.wjoin(f), mfw.get(f, False))
 
         for f in d:
             if f in mw: del mw[f]
 
             # If we're jumping between revisions (as opposed to merging),
             # and if neither the working directory nor the target rev has
             # the file, then we need to remove it from the dirstate, to
             # prevent the dirstate from listing the file when it is no
             # longer in the manifest.
             if moddirstate and linear_path and f not in m2:
                 self.dirstate.forget((f,))
 
         # Compare manifests
         for f, n in mw.iteritems():
             if choose and not choose(f): continue
             if f in m2:
                 s = 0
 
                 # is the wfile new since m1, and match m2?
                 if f not in m1:
                     t1 = self.wread(f)
                     t2 = self.file(f).read(m2[f])
                     if cmp(t1, t2) == 0:
                         n = m2[f]
                     del t1, t2
 
                 # are files different?
                 if n != m2[f]:
                     a = ma.get(f, nullid)
                     # are both different from the ancestor?
                     if n != a and m2[f] != a:
                         self.ui.debug(" %s versions differ, resolve\n" % f)
                         # merge executable bits
                         # "if we changed or they changed, change in merge"
                         a, b, c = mfa.get(f, 0), mfw[f], mf2[f]
                         mode = ((a^b) | (a^c)) ^ a
                         merge[f] = (m1.get(f, nullid), m2[f], mode)
                         s = 1
                     # are we clobbering?
                     # is remote's version newer?
                     # or are we going back in time?
                     elif force or m2[f] != a or (p2 == pa and mw[f] == m1[f]):
                         self.ui.debug(" remote %s is newer, get\n" % f)
                         get[f] = m2[f]
                         s = 1
                 elif f in umap:
                     # this unknown file is the same as the checkout
                     get[f] = m2[f]
 
                 if not s and mfw[f] != mf2[f]:
                     if force:
                         self.ui.debug(" updating permissions for %s\n" % f)
                         util.set_exec(self.wjoin(f), mf2[f])
                     else:
                         a, b, c = mfa.get(f, 0), mfw[f], mf2[f]
                         mode = ((a^b) | (a^c)) ^ a
                         if mode != b:
                             self.ui.debug(" updating permissions for %s\n" % f)
                             util.set_exec(self.wjoin(f), mode)
                 del m2[f]
             elif f in ma:
                 if n != ma[f]:
                     r = "d"
                     if not force and (linear_path or allow):
                         r = self.ui.prompt(
                             (" local changed %s which remote deleted\n" % f) +
                             "(k)eep or (d)elete?", "[kd]", "k")
                     if r == "d":
                         remove.append(f)
                 else:
                     self.ui.debug("other deleted %s\n" % f)
                     remove.append(f) # other deleted it
             else:
                 # file is created on branch or in working directory
                 if force and f not in umap:
                     self.ui.debug("remote deleted %s, clobbering\n" % f)
                     remove.append(f)
                 elif n == m1.get(f, nullid): # same as parent
                     if p2 == pa: # going backwards?
                         self.ui.debug("remote deleted %s\n" % f)
                         remove.append(f)
                     else:
                         self.ui.debug("local modified %s, keeping\n" % f)
                 else:
                     self.ui.debug("working dir created %s, keeping\n" % f)
 
         for f, n in m2.iteritems():
             if choose and not choose(f): continue
             if f[0] == "/": continue
             if f in ma and n != ma[f]:
                 r = "k"
                 if not force and (linear_path or allow):
                     r = self.ui.prompt(
                         ("remote changed %s which local deleted\n" % f) +
                         "(k)eep or (d)elete?", "[kd]", "k")
                 if r == "k": get[f] = n
             elif f not in ma:
                 self.ui.debug("remote created %s\n" % f)
                 get[f] = n
             else:
                 if force or p2 == pa: # going backwards?
                     self.ui.debug("local deleted %s, recreating\n" % f)
                     get[f] = n
                 else:
                     self.ui.debug("local deleted %s\n" % f)
 
         del mw, m1, m2, ma
 
         if force:
             for f in merge:
                 get[f] = merge[f][1]
             merge = {}
 
         if linear_path or force:
             # we don't need to do any magic, just jump to the new rev
             branch_merge = False
             p1, p2 = p2, nullid
         else:
             if not allow:
                 self.ui.status("this update spans a branch" +
                                " affecting the following files:\n")
                 fl = merge.keys() + get.keys()
                 fl.sort()
                 for f in fl:
                     cf = ""
                     if f in merge: cf = " (resolve)"
                     self.ui.status(" %s%s\n" % (f, cf))
                 self.ui.warn("aborting update spanning branches!\n")
                 self.ui.status("(use update -m to merge across branches" +
                                " or -C to lose changes)\n")
                 return 1
             branch_merge = True
 
         if moddirstate:
             self.dirstate.setparents(p1, p2)
 
         # get the files we don't need to change
         files = get.keys()
         files.sort()
         for f in files:
             if f[0] == "/": continue
             self.ui.note("getting %s\n" % f)
             t = self.file(f).read(get[f])
             try:
                 self.wwrite(f, t)
             except IOError, e:
                 if e.errno != errno.ENOENT:
                     raise
                 os.makedirs(os.path.dirname(self.wjoin(f)))
                 self.wwrite(f, t)
             util.set_exec(self.wjoin(f), mf2[f])
             if moddirstate:
                 if branch_merge:
                     self.dirstate.update([f], 'n', st_mtime=-1)
                 else:
                     self.dirstate.update([f], 'n')
 
         # merge the tricky bits
         files = merge.keys()
         files.sort()
         for f in files:
             self.ui.status("merging %s\n" % f)
             my, other, flag = merge[f]
             self.merge3(f, my, other)
             util.set_exec(self.wjoin(f), flag)
             if moddirstate:
                 if branch_merge:
                     # We've done a branch merge, mark this file as merged
                     # so that we properly record the merger later
                     self.dirstate.update([f], 'm')
                 else:
                     # We've update-merged a locally modified file, so
                     # we set the dirstate to emulate a normal checkout
                     # of that file some time in the past. Thus our
                     # merge will appear as a normal local file
                     # modification.
                     f_len = len(self.file(f).read(other))
                     self.dirstate.update([f], 'n', st_size=f_len, st_mtime=-1)
 
         remove.sort()
         for f in remove:
             self.ui.note("removing %s\n" % f)
             try:
                 os.unlink(self.wjoin(f))
             except OSError, inst:
                 self.ui.warn("update failed to remove %s: %s!\n" % (f, inst))
             # try removing directories that might now be empty
             try: os.removedirs(os.path.dirname(self.wjoin(f)))
             except: pass
         if moddirstate:
             if branch_merge:
                 self.dirstate.update(remove, 'r')
             else:
                 self.dirstate.forget(remove)
 
     def merge3(self, fn, my, other):
         """perform a 3-way merge in the working directory"""
 
         def temp(prefix, node):
             pre = "%s~%s." % (os.path.basename(fn), prefix)
             (fd, name) = tempfile.mkstemp("", pre)
             f = os.fdopen(fd, "wb")
             self.wwrite(fn, fl.read(node), f)
             f.close()
             return name
 
         fl = self.file(fn)
         base = fl.ancestor(my, other)
         a = self.wjoin(fn)
         b = temp("base", base)
         c = temp("other", other)
 
         self.ui.note("resolving %s\n" % fn)
         self.ui.debug("file %s: my %s other %s ancestor %s\n" %
                               (fn, short(my), short(other), short(base)))
 
         cmd = (os.environ.get("HGMERGE") or self.ui.config("ui", "merge")
                or "hgmerge")
         r = os.system("%s %s %s %s" % (cmd, a, b, c))
         if r:
             self.ui.warn("merging %s failed!\n" % fn)
 
         os.unlink(b)
         os.unlink(c)
 
     def verify(self):
         filelinkrevs = {}
         filenodes = {}
         changesets = revisions = files = 0
         errors = [0]
         neededmanifests = {}
 
         def err(msg):
             self.ui.warn(msg + "\n")
             errors[0] += 1
 
         seen = {}
         self.ui.status("checking changesets\n")
         for i in range(self.changelog.count()):
             changesets += 1
             n = self.changelog.node(i)
             l = self.changelog.linkrev(n)
             if l != i:
                 err("incorrect link (%d) for changeset revision %d" % (l, i))
             if n in seen:
                 err("duplicate changeset at revision %d" % i)
             seen[n] = 1
 
             for p in self.changelog.parents(n):
                 if p not in self.changelog.nodemap:
                     err("changeset %s has unknown parent %s" %
                                  (short(n), short(p)))
             try:
                 changes = self.changelog.read(n)
             except Exception, inst:
                 err("unpacking changeset %s: %s" % (short(n), inst))
 
             neededmanifests[changes[0]] = n
 
             for f in changes[3]:
                 filelinkrevs.setdefault(f, []).append(i)
 
         seen = {}
         self.ui.status("checking manifests\n")
         for i in range(self.manifest.count()):
             n = self.manifest.node(i)
             l = self.manifest.linkrev(n)
 
             if l < 0 or l >= self.changelog.count():
                 err("bad manifest link (%d) at revision %d" % (l, i))
 
             if n in neededmanifests:
                 del neededmanifests[n]
 
             if n in seen:
                 err("duplicate manifest at revision %d" % i)
 
             seen[n] = 1
 
             for p in self.manifest.parents(n):
                 if p not in self.manifest.nodemap:
                     err("manifest %s has unknown parent %s" %
                         (short(n), short(p)))
 
             try:
                 delta = mdiff.patchtext(self.manifest.delta(n))
             except KeyboardInterrupt:
                 self.ui.warn("interrupted")
                 raise
             except Exception, inst:
                 err("unpacking manifest %s: %s" % (short(n), inst))
 
             ff = [ l.split('\0') for l in delta.splitlines() ]
             for f, fn in ff:
                 filenodes.setdefault(f, {})[bin(fn[:40])] = 1
 
         self.ui.status("crosschecking files in changesets and manifests\n")
 
         for m,c in neededmanifests.items():
             err("Changeset %s refers to unknown manifest %s" %
                 (short(m), short(c)))
         del neededmanifests
 
         for f in filenodes:
             if f not in filelinkrevs:
                 err("file %s in manifest but not in changesets" % f)
 
         for f in filelinkrevs:
             if f not in filenodes:
                 err("file %s in changeset but not in manifest" % f)
 
         self.ui.status("checking files\n")
         ff = filenodes.keys()
         ff.sort()
         for f in ff:
             if f == "/dev/null": continue
             files += 1
             fl = self.file(f)
             nodes = { nullid: 1 }
             seen = {}
             for i in range(fl.count()):
                 revisions += 1
                 n = fl.node(i)
 
                 if n in seen:
                     err("%s: duplicate revision %d" % (f, i))
                 if n not in filenodes[f]:
                     err("%s: %d:%s not in manifests" % (f, i, short(n)))
                 else:
                     del filenodes[f][n]
 
                 flr = fl.linkrev(n)
                 if flr not in filelinkrevs[f]:
                     err("%s:%s points to unexpected changeset %d"
                             % (f, short(n), flr))
                 else:
                     filelinkrevs[f].remove(flr)
 
                 # verify contents
                 try:
                     t = fl.read(n)
                 except Exception, inst:
                     err("unpacking file %s %s: %s" % (f, short(n), inst))
 
                 # verify parents
                 (p1, p2) = fl.parents(n)
                 if p1 not in nodes:
                     err("file %s:%s unknown parent 1 %s" %
                         (f, short(n), short(p1)))
                 if p2 not in nodes:
                     err("file %s:%s unknown parent 2 %s" %
                             (f, short(n), short(p1)))
                 nodes[n] = 1
 
             # cross-check
             for node in filenodes[f]:
                 err("node %s in manifests not in %s" % (hex(node), f))
 
         self.ui.status("%d files, %d changesets, %d total revisions\n" %
                        (files, changesets, revisions))
 
         if errors[0]:
             self.ui.warn("%d integrity errors encountered!\n" % errors[0])
             return 1