# merge.py - directory-level update/merge handling for Mercurial

#

# Copyright 2006, 2007 Matt Mackall <mpm@selenic.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from node import nullid, nullrev, hex, bin

from i18n import _

import scmutil, util, filemerge, copies, subrepo

import errno, os, shutil

class mergestate(object):

    '''track 3-way merge state of individual files'''

    def __init__(self, repo):

        self._repo = repo

        self._dirty = False

        self._read()

    def reset(self, node=None):

        self._state = {}

        if node:

            self._local = node

        shutil.rmtree(self._repo.join("merge"), True)

        self._dirty = False

    def _read(self):

        self._state = {}

        try:

            f = self._repo.opener("merge/state")

            for i, l in enumerate(f):

                if i == 0:

                    self._local = bin(l[:-1])

                else:

                    bits = l[:-1].split("\0")

                    self._state[bits[0]] = bits[1:]

            f.close()

        except IOError, err:

            if err.errno != errno.ENOENT:

                raise

        self._dirty = False

    def commit(self):

        if self._dirty:

            f = self._repo.opener("merge/state", "w")

            f.write(hex(self._local) + "\n")

            for d, v in self._state.iteritems():

                f.write("\0".join([d] + v) + "\n")

            f.close()

            self._dirty = False

    def add(self, fcl, fco, fca, fd, flags):

        hash = util.sha1(fcl.path()).hexdigest()

        self._repo.opener.write("merge/" + hash, fcl.data())

        self._state[fd] = ['u', hash, fcl.path(), fca.path(),

                           hex(fca.filenode()), fco.path(), flags]

        self._dirty = True

    def __contains__(self, dfile):

        return dfile in self._state

    def __getitem__(self, dfile):

        return self._state[dfile][0]

    def __iter__(self):

        l = self._state.keys()

        l.sort()

        for f in l:

            yield f

    def mark(self, dfile, state):

        self._state[dfile][0] = state

        self._dirty = True

    def resolve(self, dfile, wctx, octx):

        if self[dfile] == 'r':

            return 0

        state, hash, lfile, afile, anode, ofile, flags = self._state[dfile]

        f = self._repo.opener("merge/" + hash)

        self._repo.wwrite(dfile, f.read(), flags)

        f.close()

        fcd = wctx[dfile]

        fco = octx[ofile]

        fca = self._repo.filectx(afile, fileid=anode)

        r = filemerge.filemerge(self._repo, self._local, lfile, fcd, fco, fca)

        if r is None:

            # no real conflict

            del self._state[dfile]

        elif not r:

            self.mark(dfile, 'r')

        return r

def _checkunknownfile(repo, wctx, mctx, f):

    return (not repo.dirstate._ignore(f)

        and os.path.isfile(repo.wjoin(f))

        and repo.dirstate.normalize(f) not in repo.dirstate

        and mctx[f].cmp(wctx[f]))

def _checkunknown(repo, wctx, mctx):

    "check for collisions between unknown files and files in mctx"

    error = False

    for f in mctx:

        if f not in wctx and _checkunknownfile(repo, wctx, mctx, f):

            error = True

            wctx._repo.ui.warn(_("%s: untracked file differs\n") % f)

    if error:

        raise util.Abort(_("untracked files in working directory differ "

                           "from files in requested revision"))

def _checkcollision(mctx, wctx):

    "check for case folding collisions in the destination context"

    folded = {}

    for fn in mctx:

        fold = util.normcase(fn)

        if fold in folded:

            raise util.Abort(_("case-folding collision between %s and %s")

                             % (fn, folded[fold]))

        folded[fold] = fn

    if wctx:

        # class to delay looking up copy mapping

        class pathcopies(object):

            @util.propertycache

            def map(self):

                # {dst@mctx: src@wctx} copy mapping

                return copies.pathcopies(wctx, mctx)

        pc = pathcopies()

        for fn in wctx:

            fold = util.normcase(fn)

            mfn = folded.get(fold, None)

            if mfn and mfn != fn and pc.map.get(mfn) != fn:

                raise util.Abort(_("case-folding collision between %s and %s")

                                 % (mfn, fn))

def _forgetremoved(wctx, mctx, branchmerge):

    """

    Forget removed files

    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 we're merging, and the other revision has removed a file

    that is not present in the working directory, we need to mark it

    as removed.

    """

    action = []

    state = branchmerge and 'r' or 'f'

    for f in wctx.deleted():

        if f not in mctx:

            action.append((f, state))

    if not branchmerge:

        for f in wctx.removed():

            if f not in mctx:

                action.append((f, "f"))

    return action

def manifestmerge(repo, p1, p2, pa, overwrite, partial):

    """

    Merge p1 and p2 with ancestor pa and generate merge action list

    overwrite = whether we clobber working files

    partial = function to filter file lists

    """

    def fmerge(f, f2, fa):

        """merge flags"""

        a, m, n = ma.flags(fa), m1.flags(f), m2.flags(f2)

        if m == n: # flags agree

            return m # unchanged

        if m and n and not a: # flags set, don't agree, differ from parent

            r = repo.ui.promptchoice(

                _(" conflicting flags for %s\n"

                  "(n)one, e(x)ec or sym(l)ink?") % f,

                (_("&None"), _("E&xec"), _("Sym&link")), 0)

            if r == 1:

                return "x" # Exec

            if r == 2:

                return "l" # Symlink

            return ""

        if m and m != a: # changed from a to m

            return m

        if n and n != a: # changed from a to n

            if (n == 'l' or a == 'l') and m1.get(f) != ma.get(f):

                # can't automatically merge symlink flag when there

                # are file-level conflicts here, let filemerge take

                # care of it

                return m

            return n

        return '' # flag was cleared

    def act(msg, m, f, *args):

        repo.ui.debug(" %s: %s -> %s\n" % (f, msg, m))

        action.append((f, m) + args)

    action, copy = [], {}

    if overwrite:

        pa = p1

    elif pa == p2: # backwards

        pa = p1.p1()

    elif pa and repo.ui.configbool("merge", "followcopies", True):

        copy, diverge = copies.mergecopies(repo, p1, p2, pa)

        for of, fl in diverge.iteritems():

            act("divergent renames", "dr", of, fl)

    repo.ui.note(_("resolving manifests\n"))

    repo.ui.debug(" overwrite: %s, partial: %s\n"

                  % (bool(overwrite), bool(partial)))

    repo.ui.debug(" ancestor: %s, local: %s, remote: %s\n" % (pa, p1, p2))

    m1, m2, ma = p1.manifest(), p2.manifest(), pa.manifest()

    copied = set(copy.values())

    if '.hgsubstate' in m1:

        # check whether sub state is modified

        for s in p1.substate:

            if p1.sub(s).dirty():

                m1['.hgsubstate'] += "+"

                break

    # Compare manifests

    for f, n in m1.iteritems():

        if partial and not partial(f):

            continue

        if f in m2:

            rflags = fmerge(f, f, f)

            a = ma.get(f, nullid)

            if n == m2[f] or m2[f] == a: # same or local newer

                # is file locally modified or flags need changing?

                # dirstate flags may need to be made current

                if m1.flags(f) != rflags or n[20:]:

                    act("update permissions", "e", f, rflags)

            elif n == a: # remote newer

                act("remote is newer", "g", f, rflags)

            else: # both changed

                act("versions differ", "m", f, f, f, rflags, False)

        elif f in copied: # files we'll deal with on m2 side

            pass

        elif f in copy:

            f2 = copy[f]

            if f2 not in m2: # directory rename

                act("remote renamed directory to " + f2, "d",

                    f, None, f2, m1.flags(f))

            else: # case 2 A,B/B/B or case 4,21 A/B/B

                act("local copied/moved to " + f2, "m",

                    f, f2, f, fmerge(f, f2, f2), False)

        elif f in ma: # clean, a different, no remote

            if n != ma[f]:

                if repo.ui.promptchoice(

                    _(" local changed %s which remote deleted\n"

                      "use (c)hanged version or (d)elete?") % f,

                    (_("&Changed"), _("&Delete")), 0):

                    act("prompt delete", "r", f)

                else:

                    act("prompt keep", "a", f)

            elif n[20:] == "a": # added, no remote

                act("remote deleted", "f", f)

            else:

                act("other deleted", "r", f)

    for f, n in m2.iteritems():

        if partial and not partial(f):

            continue

        if f in m1 or f in copied: # files already visited

            continue

        if f in copy:

            f2 = copy[f]

            if f2 not in m1: # directory rename

                act("local renamed directory to " + f2, "d",

                    None, f, f2, m2.flags(f))

            elif f2 in m2: # rename case 1, A/A,B/A

                act("remote copied to " + f, "m",

                    f2, f, f, fmerge(f2, f, f2), False)

            else: # case 3,20 A/B/A

                act("remote moved to " + f, "m",

                    f2, f, f, fmerge(f2, f, f2), True)

        elif f not in ma:

            if (not overwrite

                and _checkunknownfile(repo, p1, p2, f)):

                rflags = fmerge(f, f, f)

                act("remote differs from untracked local",

                    "m", f, f, f, rflags, False)

            else:

                act("remote created", "g", f, m2.flags(f))

        elif n != ma[f]:

            if repo.ui.promptchoice(

                _("remote changed %s which local deleted\n"

                  "use (c)hanged version or leave (d)eleted?") % f,

                (_("&Changed"), _("&Deleted")), 0) == 0:

                act("prompt recreating", "g", f, m2.flags(f))

    return action

def actionkey(a):

    return a[1] == 'r' and -1 or 0, a

def applyupdates(repo, action, wctx, mctx, actx, overwrite):

    """apply the merge action list to the working directory

    wctx is the working copy context

    mctx is the context to be merged into the working copy

    actx is the context of the common ancestor

    Return a tuple of counts (updated, merged, removed, unresolved) that

    describes how many files were affected by the update.

    """

    updated, merged, removed, unresolved = 0, 0, 0, 0

    ms = mergestate(repo)

    ms.reset(wctx.p1().node())

    moves = []

    action.sort(key=actionkey)

    # prescan for merges

    for a in action:

        f, m = a[:2]

        if m == 'm': # merge

            f2, fd, flags, move = a[2:]

            if f == '.hgsubstate': # merged internally

                continue

            repo.ui.debug("preserving %s for resolve of %s\n" % (f, fd))

            fcl = wctx[f]

            fco = mctx[f2]

            if mctx == actx: # backwards, use working dir parent as ancestor

                if fcl.parents():

                    fca = fcl.p1()

                else:

                    fca = repo.filectx(f, fileid=nullrev)

            else:

                fca = fcl.ancestor(fco, actx)

            if not fca:

                fca = repo.filectx(f, fileid=nullrev)

            ms.add(fcl, fco, fca, fd, flags)

            if f != fd and move:

                moves.append(f)

    audit = scmutil.pathauditor(repo.root)

    # remove renamed files after safely stored

    for f in moves:

        if os.path.lexists(repo.wjoin(f)):

            repo.ui.debug("removing %s\n" % f)

            audit(f)

            os.unlink(repo.wjoin(f))

    numupdates = len(action)

    for i, a in enumerate(action):

        f, m = a[:2]

        repo.ui.progress(_('updating'), i + 1, item=f, total=numupdates,