mercurial/hg.py

Fix long-standing excessive file merges

Since switching to the multihead approach, we've been creating
excessive file-level merges where files are marked as merged with
their ancestors.

This explicitly checks at commit time whether the two parent versions
are linearly related, and if so, reduces the file check-in to a
non-merge. Then the file is compared against the remaining parent,
and, if equal, skips check-in of that file (as it's not changed).

Since we're not checking in all files that were different between
versions, we no longer need to mark so many files for merge. This
removes most of the 'm' state marking as well.

Finally, it is possible to do a tree-level merge with no file-level
changes. This will happen if one user changes file A and another
changes file B. Thus, if we have have two parents, we allow commit to
proceed even if there are no file-level changes.

# hg.py - repository classes 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 sys, struct, os
import util
from revlog import *
from demandload import *
demandload(globals(), "re lock urllib urllib2 transaction time socket")
demandload(globals(), "tempfile httprangereader bdiff urlparse")
demandload(globals(), "bisect errno select stat")

class filelog(revlog):
    def __init__(self, opener, path):
        revlog.__init__(self, opener,
                        os.path.join("data", self.encodedir(path + ".i")),
                        os.path.join("data", self.encodedir(path + ".d")))

    # This avoids a collision between a file named foo and a dir named
    # foo.i or foo.d
    def encodedir(self, path):
        return (path
                .replace(".hg/", ".hg.hg/")
                .replace(".i/", ".i.hg/")
                .replace(".d/", ".d.hg/"))

    def decodedir(self, path):
        return (path
                .replace(".d.hg/", ".d/")
                .replace(".i.hg/", ".i/")
                .replace(".hg.hg/", ".hg/"))

    def read(self, node):
        t = self.revision(node)
        if not t.startswith('\1\n'):
            return t
        s = t.find('\1\n', 2)
        return t[s+2:]

    def readmeta(self, node):
        t = self.revision(node)
        if not t.startswith('\1\n'):
            return t
        s = t.find('\1\n', 2)
        mt = t[2:s]
        for l in mt.splitlines():
            k, v = l.split(": ", 1)
            m[k] = v
        return m

    def add(self, text, meta, transaction, link, p1=None, p2=None):
        if meta or text.startswith('\1\n'):
            mt = ""
            if meta:
                mt = [ "%s: %s\n" % (k, v) for k,v in meta.items() ]
            text = "\1\n" + "".join(mt) + "\1\n" + text
        return self.addrevision(text, transaction, link, p1, p2)

    def annotate(self, node):

        def decorate(text, rev):
            return ([rev] * len(text.splitlines()), text)

        def pair(parent, child):
            for a1, a2, b1, b2 in bdiff.blocks(parent[1], child[1]):
                child[0][b1:b2] = parent[0][a1:a2]
            return child

        # find all ancestors
        needed = {node:1}
        visit = [node]
        while visit:
            n = visit.pop(0)
            for p in self.parents(n):
                if p not in needed:
                    needed[p] = 1
                    visit.append(p)
                else:
                    # count how many times we'll use this
                    needed[p] += 1

        # sort by revision which is a topological order
        visit = [ (self.rev(n), n) for n in needed.keys() ]
        visit.sort()
        hist = {}

        for r,n in visit:
            curr = decorate(self.read(n), self.linkrev(n))
            for p in self.parents(n):
                if p != nullid:
                    curr = pair(hist[p], curr)
                    # trim the history of unneeded revs
                    needed[p] -= 1
                    if not needed[p]:
                        del hist[p]
            hist[n] = curr

        return zip(hist[n][0], hist[n][1].splitlines(1))

class manifest(revlog):
    def __init__(self, opener):
        self.mapcache = None
        self.listcache = None
        self.addlist = None
        revlog.__init__(self, opener, "00manifest.i", "00manifest.d")

    def read(self, node):
        if node == nullid: return {} # don't upset local cache
        if self.mapcache and self.mapcache[0] == node:
            return self.mapcache[1]
        text = self.revision(node)
        map = {}
        flag = {}
        self.listcache = (text, text.splitlines(1))
        for l in self.listcache[1]:
            (f, n) = l.split('\0')
            map[f] = bin(n[:40])
            flag[f] = (n[40:-1] == "x")
        self.mapcache = (node, map, flag)
        return map

    def readflags(self, node):
        if node == nullid: return {} # don't upset local cache
        if not self.mapcache or self.mapcache[0] != node:
            self.read(node)
        return self.mapcache[2]

    def diff(self, a, b):
        # this is sneaky, as we're not actually using a and b
        if self.listcache and self.addlist and self.listcache[0] == a:
            d = mdiff.diff(self.listcache[1], self.addlist, 1)
            if mdiff.patch(a, d) != b:
                sys.stderr.write("*** sortdiff failed, falling back ***\n")
                return mdiff.textdiff(a, b)
            return d
        else:
            return mdiff.textdiff(a, b)

    def add(self, map, flags, transaction, link, p1=None, p2=None,
            changed=None):
        # directly generate the mdiff delta from the data collected during
        # the bisect loop below
        def gendelta(delta):
            i = 0
            result = []
            while i < len(delta):
                start = delta[i][2]
                end = delta[i][3]
                l = delta[i][4]
                if l == None:
                    l = ""
                while i < len(delta) - 1 and start <= delta[i+1][2] \
                          and end >= delta[i+1][2]:
                    if delta[i+1][3] > end:
                        end = delta[i+1][3]
                    if delta[i+1][4]:
                        l += delta[i+1][4]
                    i += 1
                result.append(struct.pack(">lll", start, end, len(l)) +  l)
                i += 1
            return result

        # apply the changes collected during the bisect loop to our addlist
        def addlistdelta(addlist, delta):
            # apply the deltas to the addlist.  start from the bottom up
            # so changes to the offsets don't mess things up.
            i = len(delta)
            while i > 0:
                i -= 1
                start = delta[i][0]
                end = delta[i][1]
                if delta[i][4]:
                    addlist[start:end] = [delta[i][4]]
                else:
                    del addlist[start:end]
            return addlist

        # calculate the byte offset of the start of each line in the
        # manifest
        def calcoffsets(addlist):
            offsets = [0] * (len(addlist) + 1)
            offset = 0
            i = 0
            while i < len(addlist):
                offsets[i] = offset
                offset += len(addlist[i])
                i += 1
            offsets[i] = offset
            return offsets

        # if we're using the listcache, make sure it is valid and
        # parented by the same node we're diffing against
        if not changed or not self.listcache or not p1 or \
               self.mapcache[0] != p1:
            files = map.keys()
            files.sort()

            self.addlist = ["%s\000%s%s\n" %
                            (f, hex(map[f]), flags[f] and "x" or '')
                            for f in files]
            cachedelta = None
        else:
            addlist = self.listcache[1]

            # find the starting offset for each line in the add list
            offsets = calcoffsets(addlist)

            # combine the changed lists into one list for sorting
            work = [[x, 0] for x in changed[0]]
            work[len(work):] = [[x, 1] for x in changed[1]]
            work.sort()

            delta = []
            bs = 0

            for w in work:
                f = w[0]
                # bs will either be the index of the item or the insert point
                bs = bisect.bisect(addlist, f, bs)
                if bs < len(addlist):
                    fn = addlist[bs][:addlist[bs].index('\0')]
                else:
                    fn = None
                if w[1] == 0:
                    l = "%s\000%s%s\n" % (f, hex(map[f]),
                                          flags[f] and "x" or '')
                else:
                    l = None
                start = bs
                if fn != f:
                    # item not found, insert a new one
                    end = bs
                    if w[1] == 1:
                        sys.stderr.write("failed to remove %s from manifest\n"
                                         % f)
                        sys.exit(1)
                else:
                    # item is found, replace/delete the existing line
                    end = bs + 1
                delta.append([start, end, offsets[start], offsets[end], l])

            self.addlist = addlistdelta(addlist, delta)
            if self.mapcache[0] == self.tip():
                cachedelta = "".join(gendelta(delta))
            else:
                cachedelta = None

        text = "".join(self.addlist)
        if cachedelta and mdiff.patch(self.listcache[0], cachedelta) != text:
            sys.stderr.write("manifest delta failure\n")
            sys.exit(1)
        n = self.addrevision(text, transaction, link, p1, p2, cachedelta)
        self.mapcache = (n, map, flags)
        self.listcache = (text, self.addlist)
        self.addlist = None

        return n

class changelog(revlog):
    def __init__(self, opener):
        revlog.__init__(self, opener, "00changelog.i", "00changelog.d")

    def extract(self, text):
        if not text:
            return (nullid, "", "0", [], "")
        last = text.index("\n\n")
        desc = text[last + 2:]
        l = text[:last].splitlines()
        manifest = bin(l[0])
        user = l[1]
        date = l[2]
        files = l[3:]
        return (manifest, user, date, files, desc)

    def read(self, node):
        return self.extract(self.revision(node))

    def add(self, manifest, list, desc, transaction, p1=None, p2=None,
                  user=None, date=None):
        if not date:
            if time.daylight: offset = time.altzone
            else: offset = time.timezone
            date = "%d %d" % (time.time(), offset)
        list.sort()
        l = [hex(manifest), user, date] + list + ["", desc]
        text = "\n".join(l)
        return self.addrevision(text, transaction, self.count(), p1, p2)

class dirstate:
    def __init__(self, opener, ui, root):
        self.opener = opener
        self.root = root
        self.dirty = 0
        self.ui = ui
        self.map = None
        self.pl = None
        self.copies = {}
        self.ignorefunc = None

    def wjoin(self, f):
        return os.path.join(self.root, f)

    def getcwd(self):
        cwd = os.getcwd()
        if cwd == self.root: return ''
        return cwd[len(self.root) + 1:]

    def ignore(self, f):
        if not self.ignorefunc:
            bigpat = []
            try:
                l = file(self.wjoin(".hgignore"))
                for pat in l:
                    p = pat.rstrip()
                    if p:
                        try:
                            re.compile(p)
                        except:
                            self.ui.warn("ignoring invalid ignore"
                                         + " regular expression '%s'\n" % p)
                        else:
                            bigpat.append(p)
            except IOError: pass

            if bigpat:
                s = "(?:%s)" % (")|(?:".join(bigpat))
                r = re.compile(s)
                self.ignorefunc = r.search
            else:
                self.ignorefunc = util.never

        return self.ignorefunc(f)

    def __del__(self):
        if self.dirty:
            self.write()

    def __getitem__(self, key):
        try:
            return self.map[key]
        except TypeError:
            self.read()
            return self[key]

    def __contains__(self, key):
        if not self.map: self.read()
        return key in self.map

    def parents(self):
        if not self.pl:
            self.read()
        return self.pl

    def markdirty(self):
        if not self.dirty:
            self.dirty = 1

    def setparents(self, p1, p2 = nullid):
        self.markdirty()
        self.pl = p1, p2

    def state(self, key):
        try:
            return self[key][0]
        except KeyError:
            return "?"

    def read(self):
        if self.map is not None: return self.map

        self.map = {}
        self.pl = [nullid, nullid]
        try:
            st = self.opener("dirstate").read()
            if not st: return
        except: return

        self.pl = [st[:20], st[20: 40]]

        pos = 40
        while pos < len(st):
            e = struct.unpack(">cllll", st[pos:pos+17])
            l = e[4]
            pos += 17
            f = st[pos:pos + l]
            if '\0' in f:
                f, c = f.split('\0')
                self.copies[f] = c
            self.map[f] = e[:4]
            pos += l

    def copy(self, source, dest):
        self.read()
        self.markdirty()
        self.copies[dest] = source

    def copied(self, file):
        return self.copies.get(file, None)

    def update(self, files, state, **kw):
        ''' current states:
        n  normal
        m  needs merging
        r  marked for removal
        a  marked for addition'''

        if not files: return
        self.read()
        self.markdirty()
        for f in files:
            if state == "r":
                self.map[f] = ('r', 0, 0, 0)
            else:
                s = os.stat(os.path.join(self.root, f))
                st_size = kw.get('st_size', s.st_size)
                st_mtime = kw.get('st_mtime', s.st_mtime)
                self.map[f] = (state, s.st_mode, st_size, st_mtime)

    def forget(self, files):
        if not files: return
        self.read()
        self.markdirty()
        for f in files:
            try:
                del self.map[f]
            except KeyError:
                self.ui.warn("not in dirstate: %s!\n" % f)
                pass

    def clear(self):
        self.map = {}
        self.markdirty()

    def write(self):
        st = self.opener("dirstate", "w")
        st.write("".join(self.pl))
        for f, e in self.map.items():
            c = self.copied(f)
            if c:
                f = f + "\0" + c
            e = struct.pack(">cllll", e[0], e[1], e[2], e[3], len(f))
            st.write(e + f)
        self.dirty = 0

    def filterfiles(self, files):
        ret = {}
        unknown = []

        for x in files:
            if x is '.':
                return self.map.copy()
            if x not in self.map:
                unknown.append(x)
            else:
                ret[x] = self.map[x]

        if not unknown:
            return ret

        b = self.map.keys()
        b.sort()
        blen = len(b)

        for x in unknown:
            bs = bisect.bisect(b, x)
            if bs != 0 and  b[bs-1] == x:
                ret[x] = self.map[x]
                continue
            while bs < blen:
                s = b[bs]
                if len(s) > len(x) and s.startswith(x) and s[len(x)] == '/':
                    ret[s] = self.map[s]
                else:
                    break
                bs += 1
        return ret

    def walk(self, files = None, match = util.always, dc=None):
        self.read()

        # walk all files by default
        if not files:
            files = [self.root]
            if not dc:
                dc = self.map.copy()
        elif not dc:
            dc = self.filterfiles(files)

        known = {'.hg': 1}
        def seen(fn):
            if fn in known: return True
            known[fn] = 1
        def traverse():
            for ff in util.unique(files):
                f = os.path.join(self.root, ff)
                try:
                    st = os.stat(f)
                except OSError, inst:
                    if ff not in dc: self.ui.warn('%s: %s\n' % (
                        util.pathto(self.getcwd(), ff),
                        inst.strerror))
                    continue
                if stat.S_ISDIR(st.st_mode):
                    for dir, subdirs, fl in os.walk(f):
                        d = dir[len(self.root) + 1:]
                        nd = util.normpath(d)
                        if nd == '.': nd = ''
                        if seen(nd):
                            subdirs[:] = []
                            continue
                        for sd in subdirs:
                            ds = os.path.join(nd, sd +'/')
                            if self.ignore(ds) or not match(ds):
                                subdirs.remove(sd)
                        subdirs.sort()
                        fl.sort()
                        for fn in fl:
                            fn = util.pconvert(os.path.join(d, fn))
                            yield 'f', fn
                elif stat.S_ISREG(st.st_mode):
                    yield 'f', ff
                else:
                    kind = 'unknown'
                    if stat.S_ISCHR(st.st_mode): kind = 'character device'
                    elif stat.S_ISBLK(st.st_mode): kind = 'block device'
                    elif stat.S_ISFIFO(st.st_mode): kind = 'fifo'
                    elif stat.S_ISLNK(st.st_mode): kind = 'symbolic link'
                    elif stat.S_ISSOCK(st.st_mode): kind = 'socket'
                    self.ui.warn('%s: unsupported file type (type is %s)\n' % (
                        util.pathto(self.getcwd(), ff),
                        kind))

            ks = dc.keys()
            ks.sort()
            for k in ks:
                yield 'm', k

        # yield only files that match: all in dirstate, others only if
        # not in .hgignore

        for src, fn in util.unique(traverse()):
            fn = util.normpath(fn)
            if seen(fn): continue
            if fn not in dc and self.ignore(fn):
                continue
            if match(fn):
                yield src, fn

    def changes(self, files=None, match=util.always):
        self.read()
        if not files:
            dc = self.map.copy()
        else:
            dc = self.filterfiles(files)
        lookup, modified, added, unknown = [], [], [], []
        removed, deleted = [], []

        for src, fn in self.walk(files, match, dc=dc):
            try:
                s = os.stat(os.path.join(self.root, fn))
            except OSError:
                continue
            if not stat.S_ISREG(s.st_mode):
                continue
            c = dc.get(fn)
            if c:
                del dc[fn]
                if c[0] == 'm':
                    modified.append(fn)
                elif c[0] == 'a':
                    added.append(fn)
                elif c[0] == 'r':
                    unknown.append(fn)
                elif c[2] != s.st_size or (c[1] ^ s.st_mode) & 0100:
                    modified.append(fn)
                elif c[3] != s.st_mtime:
                    lookup.append(fn)
            else:
                unknown.append(fn)

        for fn, c in [(fn, c) for fn, c in dc.items() if match(fn)]:
            if c[0] == 'r':
                removed.append(fn)
            else:
                deleted.append(fn)
        return (lookup, modified, added, removed + deleted, unknown)

# used to avoid circular references so destructors work
def opener(base):
    p = base
    def o(path, mode="r"):
        if p.startswith("http://"):
            f = os.path.join(p, urllib.quote(path))
            return httprangereader.httprangereader(f)

        f = os.path.join(p, path)

        mode += "b" # for that other OS

        if mode[0] != "r":
            try:
                s = os.stat(f)
            except OSError:
                d = os.path.dirname(f)
                if not os.path.isdir(d):
                    os.makedirs(d)
            else:
                if s.st_nlink > 1:
                    file(f + ".tmp", "wb").write(file(f, "rb").read())
                    util.rename(f+".tmp", f)

        return file(f, mode)

    return o

class RepoError(Exception): pass

class localrepository:
    def __init__(self, ui, path=None, create=0):
        self.remote = 0
        if path and path.startswith("http://"):
            self.remote = 1
            self.path = path
        else:
            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 RepoError("no repo found")
                path = p
            self.path = os.path.join(path, ".hg")

            if not create and not os.path.isdir(self.path):
                raise RepoError("repository %s not found" % self.path)

        self.root = os.path.abspath(path)
        self.ui = ui

        if create:
            os.mkdir(self.path)
            os.mkdir(self.join("data"))

        self.opener = opener(self.path)
        self.wopener = opener(self.root)
        self.manifest = manifest(self.opener)
        self.changelog = changelog(self.opener)
        self.tagscache = None
        self.nodetagscache = None

        if not self.remote:
            self.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

            r = os.system(s)

            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.revision(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 RepoError("unknown revision '%s'" % key)

    def dev(self):
        if self.remote: return -1
        return os.stat(self.path).st_dev

    def local(self):
        return not self.remote

    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(self.opener, f)

    def getcwd(self):
        return self.dirstate.getcwd()

    def wfile(self, f, mode='r'):
        return self.wopener(f, mode)

    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(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])

        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.wfile(f).read()
                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)
                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, files, 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 = []
        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.wfile(f).read()
            except IOError:
                self.ui.warn("trouble committing %s!\n" % f)
                raise

            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"]))

            r = self.file(f)
            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)

        # 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 = "\n" + "HG: manifest hash %s\n" % hex(mn)
            edittext += "".join(["HG: changed %s\n" % f for f in new])
            edittext += "".join(["HG: removed %s\n" % f for f in remove])
            edittext = self.ui.edit(edittext)
            if not edittext.rstrip():
                return None
            text = edittext

        user = user or self.ui.username()
        n = self.changelog.add(mn, new, 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.wfile(fn).read()
            t2 = self.file(fn).revision(mf[fn])
            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 newer(self, nodes):
        m = {}
        nl = []
        pm = {}
        cl = self.changelog
        t = l = cl.count()

        # find the lowest numbered node
        for n in nodes:
            l = min(l, cl.rev(n))
            m[n] = 1

        for i in xrange(l, t):
            n = cl.node(i)
            if n in m: # explicitly listed
                pm[n] = 1
                nl.append(n)
                continue
            for p in cl.parents(n):
                if p in pm: # parent listed
                    pm[n] = 1
                    nl.append(n)
                    break

        return nl

    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.append(n[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] not in m and 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.append(p)
                        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:
            if f in m:
                raise RepoError("already have changeset " + short(f[:4]))

        if base.keys() == [nullid]:
            self.ui.warn("warning: pulling from an unrelated repository!\n")

        self.ui.note("adding new changesets starting at " +
                     " ".join([short(f) for f in fetch]) + "\n")

        self.ui.debug("%d total queries\n" % reqcnt)

        return fetch

    def findoutgoing(self, remote, base=None, heads=None):
        if base == None:
            base = {}
            self.findincoming(remote, base, heads)

        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):
        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

        cg = remote.changegroup(fetch)
        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 changegroup(self, basenodes):
        class genread:
            def __init__(self, generator):
                self.g = generator
                self.buf = ""
            def fillbuf(self):
                self.buf += "".join(self.g)

            def read(self, l):
                while l > len(self.buf):
                    try:
                        self.buf += self.g.next()
                    except StopIteration:
                        break
                d, self.buf = self.buf[:l], self.buf[l:]
                return d

        def gengroup():
            nodes = self.newer(basenodes)

            # construct the link map
            linkmap = {}
            for n in nodes:
                linkmap[self.changelog.rev(n)] = n

            # construct a list of all changed files
            changed = {}
            for n in nodes:
                c = self.changelog.read(n)
                for f in c[3]:
                    changed[f] = 1
            changed = changed.keys()
            changed.sort()

            # the changegroup is changesets + manifests + all file revs
            revs = [ self.changelog.rev(n) for n in nodes ]

            for y in self.changelog.group(linkmap): yield y
            for y in self.manifest.group(linkmap): yield y
            for f in changed:
                yield struct.pack(">l", len(f) + 4) + f
                g = self.file(f).group(linkmap)
                for y in g:
                    yield y

            yield struct.pack(">l", 0)

        return genread(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 ""
            return source.read(l - 4)

        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()

        # pull off the changeset group
        self.ui.status("adding changesets\n")
        co = self.changelog.tip()
        cn = self.changelog.addgroup(getgroup(), csmap, tr, 1) # unique
        changesets = self.changelog.rev(cn) - self.changelog.rev(co)

        # 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

        self.ui.status(("added %d changesets" +
                        " with %d changes to %d files\n")
                       % (changesets, revisions, files))

        tr.close()

        if not self.hook("changegroup"):
            return 1

        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 = []
        mark = {}

        # 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.wfile(f).read()
                    t2 = self.file(f).revision(m2[f])
                    if cmp(t1, t2) == 0:
                        mark[f] = 1
                        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
                    else:
                        mark[f] = 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)
                            mark[f] = 1
                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:
                if 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 created %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
            mode = 'n'
            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
            mode = 'm'

        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.wfile(f, "w").write(t)
            except IOError:
                os.makedirs(os.path.dirname(self.wjoin(f)))
                self.wfile(f, "w").write(t)
            util.set_exec(self.wjoin(f), mf2[f])
            if moddirstate:
                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)
            m, o, flag = merge[f]
            self.merge3(f, m, o)
            util.set_exec(self.wjoin(f), flag)
            if moddirstate:
                if mode == 'm':
                    # only update dirstate on branch merge, otherwise we
                    # could mark files with changes as unchanged
                    self.dirstate.update([f], mode)
                elif p2 == nullid:
                    # update dirstate from parent1's manifest
                    m1n = self.changelog.read(p1)[0]
                    m1 = self.manifest.read(m1n)
                    f_len = len(self.file(f).read(m1[f]))
                    self.dirstate.update([f], mode, st_size=f_len, st_mtime=0)
                else:
                    self.ui.warn("Second parent without branch merge!?\n"
                                 "Dirstate for file %s may be wrong.\n" % f)

        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 mode == 'n':
                self.dirstate.forget(remove)
            else:
                self.dirstate.update(remove, 'r')

    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")
            f.write(fl.revision(node))
            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: other %s ancestor %s\n" %
                              (fn, 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

        seen = {}
        self.ui.status("checking changesets\n")
        for i in range(self.changelog.count()):
            changesets += 1
            n = self.changelog.node(i)
            if n in seen:
                self.ui.warn("duplicate changeset at revision %d\n" % i)
                errors += 1
            seen[n] = 1

            for p in self.changelog.parents(n):
                if p not in self.changelog.nodemap:
                    self.ui.warn("changeset %s has unknown parent %s\n" %
                                 (short(n), short(p)))
                    errors += 1
            try:
                changes = self.changelog.read(n)
            except Exception, inst:
                self.ui.warn("unpacking changeset %s: %s\n" % (short(n), inst))
                errors += 1

            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)
            if n in seen:
                self.ui.warn("duplicate manifest at revision %d\n" % i)
                errors += 1
            seen[n] = 1

            for p in self.manifest.parents(n):
                if p not in self.manifest.nodemap:
                    self.ui.warn("manifest %s has unknown parent %s\n" %
                            (short(n), short(p)))
                    errors += 1

            try:
                delta = mdiff.patchtext(self.manifest.delta(n))
            except KeyboardInterrupt:
                self.ui.warn("aborted")
                sys.exit(0)
            except Exception, inst:
                self.ui.warn("unpacking manifest %s: %s\n"
                             % (short(n), inst))
                errors += 1

            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 f in filenodes:
            if f not in filelinkrevs:
                self.ui.warn("file %s in manifest but not in changesets\n" % f)
                errors += 1

        for f in filelinkrevs:
            if f not in filenodes:
                self.ui.warn("file %s in changeset but not in manifest\n" % f)
                errors += 1

        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:
                    self.ui.warn("%s: duplicate revision %d\n" % (f, i))
                    errors += 1

                if n not in filenodes[f]:
                    self.ui.warn("%s: %d:%s not in manifests\n"
                                 % (f, i, short(n)))
                    errors += 1
                else:
                    del filenodes[f][n]

                flr = fl.linkrev(n)
                if flr not in filelinkrevs[f]:
                    self.ui.warn("%s:%s points to unexpected changeset %d\n"
                            % (f, short(n), fl.linkrev(n)))
                    errors += 1
                else:
                    filelinkrevs[f].remove(flr)

                # verify contents
                try:
                    t = fl.read(n)
                except Exception, inst:
                    self.ui.warn("unpacking file %s %s: %s\n"
                                 % (f, short(n), inst))
                    errors += 1

                # verify parents
                (p1, p2) = fl.parents(n)
                if p1 not in nodes:
                    self.ui.warn("file %s:%s unknown parent 1 %s" %
                            (f, short(n), short(p1)))
                    errors += 1
                if p2 not in nodes:
                    self.ui.warn("file %s:%s unknown parent 2 %s" %
                            (f, short(n), short(p1)))
                    errors += 1
                nodes[n] = 1

            # cross-check
            for node in filenodes[f]:
                self.ui.warn("node %s in manifests not in %s\n"
                             % (hex(node), f))
                errors += 1

        self.ui.status("%d files, %d changesets, %d total revisions\n" %
                       (files, changesets, revisions))

        if errors:
            self.ui.warn("%d integrity errors encountered!\n" % errors)
            return 1

class remoterepository:
    def local(self):
        return False

class httprepository(remoterepository):
    def __init__(self, ui, path):
        # fix missing / after hostname
        s = urlparse.urlsplit(path)
        partial = s[2]
        if not partial: partial = "/"
        self.url = urlparse.urlunsplit((s[0], s[1], partial, '', ''))
        self.ui = ui
        no_list = [ "localhost", "127.0.0.1" ]
        host = ui.config("http_proxy", "host")
        if host is None:
            host = os.environ.get("http_proxy")
        if host and host.startswith('http://'):
            host = host[7:]
        user = ui.config("http_proxy", "user")
        passwd = ui.config("http_proxy", "passwd")
        no = ui.config("http_proxy", "no")
        if no is None:
            no = os.environ.get("no_proxy")
        if no:
            no_list = no_list + no.split(",")

        no_proxy = 0
        for h in no_list:
            if (path.startswith("http://" + h + "/") or
                path.startswith("http://" + h + ":") or
                path == "http://" + h):
                no_proxy = 1

        # Note: urllib2 takes proxy values from the environment and those will
        # take precedence
        for env in ["HTTP_PROXY", "http_proxy", "no_proxy"]:
            try:
                if os.environ.has_key(env):
                    del os.environ[env]
            except OSError:
                pass

        proxy_handler = urllib2.BaseHandler()
        if host and not no_proxy:
            proxy_handler = urllib2.ProxyHandler({"http" : "http://" + host})

        authinfo = None
        if user and passwd:
            passmgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
            passmgr.add_password(None, host, user, passwd)
            authinfo = urllib2.ProxyBasicAuthHandler(passmgr)

        opener = urllib2.build_opener(proxy_handler, authinfo)
        urllib2.install_opener(opener)

    def dev(self):
        return -1

    def do_cmd(self, cmd, **args):
        self.ui.debug("sending %s command\n" % cmd)
        q = {"cmd": cmd}
        q.update(args)
        qs = urllib.urlencode(q)
        cu = "%s?%s" % (self.url, qs)
        resp = urllib2.urlopen(cu)
        proto = resp.headers['content-type']

        # accept old "text/plain" and "application/hg-changegroup" for now
        if not proto.startswith('application/mercurial') and \
               not proto.startswith('text/plain') and \
               not proto.startswith('application/hg-changegroup'):
            raise RepoError("'%s' does not appear to be an hg repository"
                            % self.url)

        if proto.startswith('application/mercurial'):
            version = proto[22:]
            if float(version) > 0.1:
                raise RepoError("'%s' uses newer protocol %s" %
                                (self.url, version))

        return resp

    def heads(self):
        d = self.do_cmd("heads").read()
        try:
            return map(bin, d[:-1].split(" "))
        except:
            self.ui.warn("unexpected response:\n" + d[:400] + "\n...\n")
            raise

    def branches(self, nodes):
        n = " ".join(map(hex, nodes))
        d = self.do_cmd("branches", nodes=n).read()
        try:
            br = [ tuple(map(bin, b.split(" "))) for b in d.splitlines() ]
            return br
        except:
            self.ui.warn("unexpected response:\n" + d[:400] + "\n...\n")
            raise

    def between(self, pairs):
        n = "\n".join(["-".join(map(hex, p)) for p in pairs])
        d = self.do_cmd("between", pairs=n).read()
        try:
            p = [ l and map(bin, l.split(" ")) or [] for l in d.splitlines() ]
            return p
        except:
            self.ui.warn("unexpected response:\n" + d[:400] + "\n...\n")
            raise

    def changegroup(self, nodes):
        n = " ".join(map(hex, nodes))
        f = self.do_cmd("changegroup", roots=n)
        bytes = 0

        class zread:
            def __init__(self, f):
                self.zd = zlib.decompressobj()
                self.f = f
                self.buf = ""
            def read(self, l):
                while l > len(self.buf):
                    r = self.f.read(4096)
                    if r:
                        self.buf += self.zd.decompress(r)
                    else:
                        self.buf += self.zd.flush()
                        break
                d, self.buf = self.buf[:l], self.buf[l:]
                return d

        return zread(f)

class remotelock:
    def __init__(self, repo):
        self.repo = repo
    def release(self):
        self.repo.unlock()
        self.repo = None
    def __del__(self):
        if self.repo:
            self.release()

class sshrepository(remoterepository):
    def __init__(self, ui, path):
        self.url = path
        self.ui = ui

        m = re.match(r'ssh://(([^@]+)@)?([^:/]+)(:(\d+))?(/(.*))', path)
        if not m:
            raise RepoError("couldn't parse destination %s" % path)

        self.user = m.group(2)
        self.host = m.group(3)
        self.port = m.group(5)
        self.path = m.group(7)

        args = self.user and ("%s@%s" % (self.user, self.host)) or self.host
        args = self.port and ("%s -p %s") % (args, self.port) or args
        path = self.path or ""

        if not path:
            raise RepoError("no remote repository path specified")

        sshcmd = self.ui.config("ui", "ssh", "ssh")
        remotecmd = self.ui.config("ui", "remotecmd", "hg")
        cmd = "%s %s '%s -R %s serve --stdio'"
        cmd = cmd % (sshcmd, args, remotecmd, path)

        self.pipeo, self.pipei, self.pipee = os.popen3(cmd)

    def readerr(self):
        while 1:
            r,w,x = select.select([self.pipee], [], [], 0)
            if not r: break
            l = self.pipee.readline()
            if not l: break
            self.ui.status("remote: ", l)

    def __del__(self):
        try:
            self.pipeo.close()
            self.pipei.close()
            for l in self.pipee:
                self.ui.status("remote: ", l)
            self.pipee.close()
        except:
            pass

    def dev(self):
        return -1

    def do_cmd(self, cmd, **args):
        self.ui.debug("sending %s command\n" % cmd)
        self.pipeo.write("%s\n" % cmd)
        for k, v in args.items():
            self.pipeo.write("%s %d\n" % (k, len(v)))
            self.pipeo.write(v)
        self.pipeo.flush()

        return self.pipei

    def call(self, cmd, **args):
        r = self.do_cmd(cmd, **args)
        l = r.readline()
        self.readerr()
        try:
            l = int(l)
        except:
            raise RepoError("unexpected response '%s'" % l)
        return r.read(l)

    def lock(self):
        self.call("lock")
        return remotelock(self)

    def unlock(self):
        self.call("unlock")

    def heads(self):
        d = self.call("heads")
        try:
            return map(bin, d[:-1].split(" "))
        except:
            raise RepoError("unexpected response '%s'" % (d[:400] + "..."))

    def branches(self, nodes):
        n = " ".join(map(hex, nodes))
        d = self.call("branches", nodes=n)
        try:
            br = [ tuple(map(bin, b.split(" "))) for b in d.splitlines() ]
            return br
        except:
            raise RepoError("unexpected response '%s'" % (d[:400] + "..."))

    def between(self, pairs):
        n = "\n".join(["-".join(map(hex, p)) for p in pairs])
        d = self.call("between", pairs=n)
        try:
            p = [ l and map(bin, l.split(" ")) or [] for l in d.splitlines() ]
            return p
        except:
            raise RepoError("unexpected response '%s'" % (d[:400] + "..."))

    def changegroup(self, nodes):
        n = " ".join(map(hex, nodes))
        f = self.do_cmd("changegroup", roots=n)
        return self.pipei

    def addchangegroup(self, cg):
        d = self.call("addchangegroup")
        if d:
            raise RepoError("push refused: %s", d)

        while 1:
            d = cg.read(4096)
            if not d: break
            self.pipeo.write(d)
            self.readerr()

        self.pipeo.flush()

        self.readerr()
        l = int(self.pipei.readline())
        return self.pipei.read(l) != ""

class httpsrepository(httprepository):
    pass

def repository(ui, path=None, create=0):
    if path:
        if path.startswith("http://"):
            return httprepository(ui, path)
        if path.startswith("https://"):
            return httpsrepository(ui, path)
        if path.startswith("hg://"):
            return httprepository(ui, path.replace("hg://", "http://"))
        if path.startswith("old-http://"):
            return localrepository(ui, path.replace("old-http://", "http://"))
        if path.startswith("ssh://"):
            return sshrepository(ui, path)

    return localrepository(ui, path, create)