# Copyright 2009-2010 Gregory P. Ward
# Copyright 2009-2010 Intelerad Medical Systems Incorporated
# Copyright 2010-2011 Fog Creek Software
# Copyright 2010-2011 Unity Technologies
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''Overridden Mercurial commands and functions for the largefiles extension'''

import os
import copy

from mercurial import hg, util, cmdutil, scmutil, match as match_, \
        archival, pathutil, revset
from mercurial.i18n import _
from mercurial.node import hex

import lfutil
import lfcommands
import basestore

# -- Utility functions: commonly/repeatedly needed functionality ---------------

def composelargefilematcher(match, manifest):
    '''create a matcher that matches only the largefiles in the original
    matcher'''
    m = copy.copy(match)
    lfile = lambda f: lfutil.standin(f) in manifest
    m._files = filter(lfile, m._files)
    m._fmap = set(m._files)
    m._always = False
    origmatchfn = m.matchfn
    m.matchfn = lambda f: lfile(f) and origmatchfn(f)
    return m

def composenormalfilematcher(match, manifest, exclude=None):
    excluded = set()
    if exclude is not None:
        excluded.update(exclude)

    m = copy.copy(match)
    notlfile = lambda f: not (lfutil.isstandin(f) or lfutil.standin(f) in
            manifest or f in excluded)
    m._files = filter(notlfile, m._files)
    m._fmap = set(m._files)
    m._always = False
    origmatchfn = m.matchfn
    m.matchfn = lambda f: notlfile(f) and origmatchfn(f)
    return m

def installnormalfilesmatchfn(manifest):
    '''installmatchfn with a matchfn that ignores all largefiles'''
    def overridematch(ctx, pats=[], opts={}, globbed=False,
            default='relpath'):
        match = oldmatch(ctx, pats, opts, globbed, default)
        return composenormalfilematcher(match, manifest)
    oldmatch = installmatchfn(overridematch)

def installmatchfn(f):
    '''monkey patch the scmutil module with a custom match function.
    Warning: it is monkey patching the _module_ on runtime! Not thread safe!'''
    oldmatch = scmutil.match
    setattr(f, 'oldmatch', oldmatch)
    scmutil.match = f
    return oldmatch

def restorematchfn():
    '''restores scmutil.match to what it was before installmatchfn
    was called.  no-op if scmutil.match is its original function.

    Note that n calls to installmatchfn will require n calls to
    restore the original matchfn.'''
    scmutil.match = getattr(scmutil.match, 'oldmatch')

def installmatchandpatsfn(f):
    oldmatchandpats = scmutil.matchandpats
    setattr(f, 'oldmatchandpats', oldmatchandpats)
    scmutil.matchandpats = f
    return oldmatchandpats

def restorematchandpatsfn():
    '''restores scmutil.matchandpats to what it was before
    installmatchandpatsfn was called. No-op if scmutil.matchandpats
    is its original function.

    Note that n calls to installmatchandpatsfn will require n calls
    to restore the original matchfn.'''
    scmutil.matchandpats = getattr(scmutil.matchandpats, 'oldmatchandpats',
            scmutil.matchandpats)

def addlargefiles(ui, repo, isaddremove, matcher, **opts):
    large = opts.get('large')
    lfsize = lfutil.getminsize(
        ui, lfutil.islfilesrepo(repo), opts.get('lfsize'))

    lfmatcher = None
    if lfutil.islfilesrepo(repo):
        lfpats = ui.configlist(lfutil.longname, 'patterns', default=[])
        if lfpats:
            lfmatcher = match_.match(repo.root, '', list(lfpats))

    lfnames = []
    m = copy.copy(matcher)
    m.bad = lambda x, y: None
    wctx = repo[None]
    for f in repo.walk(m):
        exact = m.exact(f)
        lfile = lfutil.standin(f) in wctx
        nfile = f in wctx
        exists = lfile or nfile

        # addremove in core gets fancy with the name, add doesn't
        if isaddremove:
            name = m.uipath(f)
        else:
            name = m.rel(f)

        # Don't warn the user when they attempt to add a normal tracked file.
        # The normal add code will do that for us.
        if exact and exists:
            if lfile:
                ui.warn(_('%s already a largefile\n') % name)
            continue

        if (exact or not exists) and not lfutil.isstandin(f):
            # In case the file was removed previously, but not committed
            # (issue3507)
            if not repo.wvfs.exists(f):
                continue

            abovemin = (lfsize and
                        repo.wvfs.lstat(f).st_size >= lfsize * 1024 * 1024)
            if large or abovemin or (lfmatcher and lfmatcher(f)):
                lfnames.append(f)
                if ui.verbose or not exact:
                    ui.status(_('adding %s as a largefile\n') % name)

    bad = []

    # Need to lock, otherwise there could be a race condition between
    # when standins are created and added to the repo.
    wlock = repo.wlock()
    try:
        if not opts.get('dry_run'):
            standins = []
            lfdirstate = lfutil.openlfdirstate(ui, repo)
            for f in lfnames:
                standinname = lfutil.standin(f)
                lfutil.writestandin(repo, standinname, hash='',
                    executable=lfutil.getexecutable(repo.wjoin(f)))
                standins.append(standinname)
                if lfdirstate[f] == 'r':
                    lfdirstate.normallookup(f)
                else:
                    lfdirstate.add(f)
            lfdirstate.write()
            bad += [lfutil.splitstandin(f)
                    for f in repo[None].add(standins)
                    if f in m.files()]

        added = [f for f in lfnames if f not in bad]
    finally:
        wlock.release()
    return added, bad

def removelargefiles(ui, repo, isaddremove, matcher, **opts):
    after = opts.get('after')
    m = composelargefilematcher(matcher, repo[None].manifest())
    try:
        repo.lfstatus = True
        s = repo.status(match=m, clean=not isaddremove)
    finally:
        repo.lfstatus = False
    manifest = repo[None].manifest()
    modified, added, deleted, clean = [[f for f in list
                                        if lfutil.standin(f) in manifest]
                                       for list in (s.modified, s.added,
                                                    s.deleted, s.clean)]

    def warn(files, msg):
        for f in files:
            ui.warn(msg % m.rel(f))
        return int(len(files) > 0)

    result = 0

    if after:
        remove = deleted
        result = warn(modified + added + clean,
                      _('not removing %s: file still exists\n'))
    else:
        remove = deleted + clean
        result = warn(modified, _('not removing %s: file is modified (use -f'
                                  ' to force removal)\n'))
        result = warn(added, _('not removing %s: file has been marked for add'
                               ' (use forget to undo)\n')) or result

    # Need to lock because standin files are deleted then removed from the
    # repository and we could race in-between.
    wlock = repo.wlock()
    try:
        lfdirstate = lfutil.openlfdirstate(ui, repo)
        for f in sorted(remove):
            if ui.verbose or not m.exact(f):
                # addremove in core gets fancy with the name, remove doesn't
                if isaddremove:
                    name = m.uipath(f)
                else:
                    name = m.rel(f)
                ui.status(_('removing %s\n') % name)

            if not opts.get('dry_run'):
                if not after:
                    util.unlinkpath(repo.wjoin(f), ignoremissing=True)

        if opts.get('dry_run'):
            return result

        remove = [lfutil.standin(f) for f in remove]
        # If this is being called by addremove, let the original addremove
        # function handle this.
        if not isaddremove:
            for f in remove:
                util.unlinkpath(repo.wjoin(f), ignoremissing=True)
        repo[None].forget(remove)

        for f in remove:
            lfutil.synclfdirstate(repo, lfdirstate, lfutil.splitstandin(f),
                                  False)

        lfdirstate.write()
    finally:
        wlock.release()

    return result

# For overriding mercurial.hgweb.webcommands so that largefiles will
# appear at their right place in the manifests.
def decodepath(orig, path):
    return lfutil.splitstandin(path) or path

# -- Wrappers: modify existing commands --------------------------------

def overrideadd(orig, ui, repo, *pats, **opts):
    if opts.get('normal') and opts.get('large'):
        raise util.Abort(_('--normal cannot be used with --large'))
    return orig(ui, repo, *pats, **opts)

def cmdutiladd(orig, ui, repo, matcher, prefix, explicitonly, **opts):
    # The --normal flag short circuits this override
    if opts.get('normal'):
        return orig(ui, repo, matcher, prefix, explicitonly, **opts)

    ladded, lbad = addlargefiles(ui, repo, False, matcher, **opts)
    normalmatcher = composenormalfilematcher(matcher, repo[None].manifest(),
                                             ladded)
    bad = orig(ui, repo, normalmatcher, prefix, explicitonly, **opts)

    bad.extend(f for f in lbad)
    return bad

def cmdutilremove(orig, ui, repo, matcher, prefix, after, force, subrepos):
    normalmatcher = composenormalfilematcher(matcher, repo[None].manifest())
    result = orig(ui, repo, normalmatcher, prefix, after, force, subrepos)
    return removelargefiles(ui, repo, False, matcher, after=after,
                            force=force) or result

def overridestatusfn(orig, repo, rev2, **opts):
    try:
        repo._repo.lfstatus = True
        return orig(repo, rev2, **opts)
    finally:
        repo._repo.lfstatus = False

def overridestatus(orig, ui, repo, *pats, **opts):
    try:
        repo.lfstatus = True
        return orig(ui, repo, *pats, **opts)
    finally:
        repo.lfstatus = False

def overridedirty(orig, repo, ignoreupdate=False):
    try:
        repo._repo.lfstatus = True
        return orig(repo, ignoreupdate)
    finally:
        repo._repo.lfstatus = False

def overridelog(orig, ui, repo, *pats, **opts):
    def overridematchandpats(ctx, pats=[], opts={}, globbed=False,
            default='relpath'):
        """Matcher that merges root directory with .hglf, suitable for log.
        It is still possible to match .hglf directly.
        For any listed files run log on the standin too.
        matchfn tries both the given filename and with .hglf stripped.
        """
        matchandpats = oldmatchandpats(ctx, pats, opts, globbed, default)
        m, p = copy.copy(matchandpats)

        if m.always():
            # We want to match everything anyway, so there's no benefit trying
            # to add standins.
            return matchandpats

        pats = set(p)

        def fixpats(pat, tostandin=lfutil.standin):
            kindpat = match_._patsplit(pat, None)

            if kindpat[0] is not None:
                return kindpat[0] + ':' + tostandin(kindpat[1])
            return tostandin(kindpat[1])

        if m._cwd:
            hglf = lfutil.shortname
            back = util.pconvert(m.rel(hglf)[:-len(hglf)])

            def tostandin(f):
                # The file may already be a standin, so trucate the back
                # prefix and test before mangling it.  This avoids turning
                # 'glob:../.hglf/foo*' into 'glob:../.hglf/../.hglf/foo*'.
                if f.startswith(back) and lfutil.splitstandin(f[len(back):]):
                    return f

                # An absolute path is from outside the repo, so truncate the
                # path to the root before building the standin.  Otherwise cwd
                # is somewhere in the repo, relative to root, and needs to be
                # prepended before building the standin.
                if os.path.isabs(m._cwd):
                    f = f[len(back):]
                else:
                    f = m._cwd + '/' + f
                return back + lfutil.standin(f)

            pats.update(fixpats(f, tostandin) for f in p)
        else:
            def tostandin(f):
                if lfutil.splitstandin(f):
                    return f
                return lfutil.standin(f)
            pats.update(fixpats(f, tostandin) for f in p)

        for i in range(0, len(m._files)):
            # Don't add '.hglf' to m.files, since that is already covered by '.'
            if m._files[i] == '.':
                continue
            standin = lfutil.standin(m._files[i])
            # If the "standin" is a directory, append instead of replace to
            # support naming a directory on the command line with only
            # largefiles.  The original directory is kept to support normal
            # files.
            if standin in repo[ctx.node()]:
                m._files[i] = standin
            elif m._files[i] not in repo[ctx.node()] \
                    and repo.wvfs.isdir(standin):
                m._files.append(standin)

        m._fmap = set(m._files)
        m._always = False
        origmatchfn = m.matchfn
        def lfmatchfn(f):
            lf = lfutil.splitstandin(f)
            if lf is not None and origmatchfn(lf):
                return True
            r = origmatchfn(f)
            return r
        m.matchfn = lfmatchfn

        ui.debug('updated patterns: %s\n' % sorted(pats))
        return m, pats

    # For hg log --patch, the match object is used in two different senses:
    # (1) to determine what revisions should be printed out, and
    # (2) to determine what files to print out diffs for.
    # The magic matchandpats override should be used for case (1) but not for
    # case (2).
    def overridemakelogfilematcher(repo, pats, opts):
        wctx = repo[None]
        match, pats = oldmatchandpats(wctx, pats, opts)
        return lambda rev: match

    oldmatchandpats = installmatchandpatsfn(overridematchandpats)
    oldmakelogfilematcher = cmdutil._makenofollowlogfilematcher
    setattr(cmdutil, '_makenofollowlogfilematcher', overridemakelogfilematcher)

    try:
        return orig(ui, repo, *pats, **opts)
    finally:
        restorematchandpatsfn()
        setattr(cmdutil, '_makenofollowlogfilematcher', oldmakelogfilematcher)

def overrideverify(orig, ui, repo, *pats, **opts):
    large = opts.pop('large', False)
    all = opts.pop('lfa', False)
    contents = opts.pop('lfc', False)

    result = orig(ui, repo, *pats, **opts)
    if large or all or contents:
        result = result or lfcommands.verifylfiles(ui, repo, all, contents)
    return result

def overridedebugstate(orig, ui, repo, *pats, **opts):
    large = opts.pop('large', False)
    if large:
        class fakerepo(object):
            dirstate = lfutil.openlfdirstate(ui, repo)
        orig(ui, fakerepo, *pats, **opts)
    else:
        orig(ui, repo, *pats, **opts)

# Before starting the manifest merge, merge.updates will call
# _checkunknownfile to check if there are any files in the merged-in
# changeset that collide with unknown files in the working copy.
#
# The largefiles are seen as unknown, so this prevents us from merging
# in a file 'foo' if we already have a largefile with the same name.
#
# The overridden function filters the unknown files by removing any
# largefiles. This makes the merge proceed and we can then handle this
# case further in the overridden calculateupdates function below.
def overridecheckunknownfile(origfn, repo, wctx, mctx, f, f2=None):
    if lfutil.standin(repo.dirstate.normalize(f)) in wctx:
        return False
    return origfn(repo, wctx, mctx, f, f2)

# The manifest merge handles conflicts on the manifest level. We want
# to handle changes in largefile-ness of files at this level too.
#
# The strategy is to run the original calculateupdates and then process
# the action list it outputs. There are two cases we need to deal with:
#
# 1. Normal file in p1, largefile in p2. Here the largefile is
#    detected via its standin file, which will enter the working copy
#    with a "get" action. It is not "merge" since the standin is all
#    Mercurial is concerned with at this level -- the link to the
#    existing normal file is not relevant here.
#
# 2. Largefile in p1, normal file in p2. Here we get a "merge" action
#    since the largefile will be present in the working copy and
#    different from the normal file in p2. Mercurial therefore
#    triggers a merge action.
#
# In both cases, we prompt the user and emit new actions to either
# remove the standin (if the normal file was kept) or to remove the
# normal file and get the standin (if the largefile was kept). The
# default prompt answer is to use the largefile version since it was
# presumably changed on purpose.
#
# Finally, the merge.applyupdates function will then take care of
# writing the files into the working copy and lfcommands.updatelfiles
# will update the largefiles.
def overridecalculateupdates(origfn, repo, p1, p2, pas, branchmerge, force,
                             partial, acceptremote, followcopies):
    overwrite = force and not branchmerge
    actions, diverge, renamedelete = origfn(
        repo, p1, p2, pas, branchmerge, force, partial, acceptremote,
        followcopies)

    if overwrite:
        return actions, diverge, renamedelete

    # Convert to dictionary with filename as key and action as value.
    lfiles = set()
    for f in actions:
        splitstandin = f and lfutil.splitstandin(f)
        if splitstandin in p1:
            lfiles.add(splitstandin)
        elif lfutil.standin(f) in p1:
            lfiles.add(f)

    for lfile in lfiles:
        standin = lfutil.standin(lfile)
        (lm, largs, lmsg) = actions.get(lfile, (None, None, None))
        (sm, sargs, smsg) = actions.get(standin, (None, None, None))
        if sm in ('g', 'dc') and lm != 'r':
            # Case 1: normal file in the working copy, largefile in
            # the second parent
            usermsg = _('remote turned local normal file %s into a largefile\n'
                        'use (l)argefile or keep (n)ormal file?'
                        '$$ &Largefile $$ &Normal file') % lfile
            if repo.ui.promptchoice(usermsg, 0) == 0: # pick remote largefile
                actions[lfile] = ('r', None, 'replaced by standin')
                actions[standin] = ('g', sargs, 'replaces standin')
            else: # keep local normal file
                actions[lfile] = ('k', None, 'replaces standin')
                if branchmerge:
                    actions[standin] = ('k', None, 'replaced by non-standin')
                else:
                    actions[standin] = ('r', None, 'replaced by non-standin')
        elif lm in ('g', 'dc') and sm != 'r':
            # Case 2: largefile in the working copy, normal file in
            # the second parent
            usermsg = _('remote turned local largefile %s into a normal file\n'
                    'keep (l)argefile or use (n)ormal file?'
                    '$$ &Largefile $$ &Normal file') % lfile
            if repo.ui.promptchoice(usermsg, 0) == 0: # keep local largefile
                if branchmerge:
                    # largefile can be restored from standin safely
                    actions[lfile] = ('k', None, 'replaced by standin')
                    actions[standin] = ('k', None, 'replaces standin')
                else:
                    # "lfile" should be marked as "removed" without
                    # removal of itself
                    actions[lfile] = ('lfmr', None,
                                      'forget non-standin largefile')

                    # linear-merge should treat this largefile as 're-added'
                    actions[standin] = ('a', None, 'keep standin')
            else: # pick remote normal file
                actions[lfile] = ('g', largs, 'replaces standin')
                actions[standin] = ('r', None, 'replaced by non-standin')

    return actions, diverge, renamedelete

def mergerecordupdates(orig, repo, actions, branchmerge):
    if 'lfmr' in actions:
        lfdirstate = lfutil.openlfdirstate(repo.ui, repo)
        for lfile, args, msg in actions['lfmr']:
            # this should be executed before 'orig', to execute 'remove'
            # before all other actions
            repo.dirstate.remove(lfile)
            # make sure lfile doesn't get synclfdirstate'd as normal
            lfdirstate.add(lfile)
        lfdirstate.write()

    return orig(repo, actions, branchmerge)


# Override filemerge to prompt the user about how they wish to merge
# largefiles. This will handle identical edits without prompting the user.
def overridefilemerge(origfn, repo, mynode, orig, fcd, fco, fca, labels=None):
    if not lfutil.isstandin(orig):
        return origfn(repo, mynode, orig, fcd, fco, fca, labels=labels)

    ahash = fca.data().strip().lower()
    dhash = fcd.data().strip().lower()
    ohash = fco.data().strip().lower()
    if (ohash != ahash and
        ohash != dhash and
        (dhash == ahash or
         repo.ui.promptchoice(
             _('largefile %s has a merge conflict\nancestor was %s\n'
               'keep (l)ocal %s or\ntake (o)ther %s?'
               '$$ &Local $$ &Other') %
               (lfutil.splitstandin(orig), ahash, dhash, ohash),
             0) == 1)):
        repo.wwrite(fcd.path(), fco.data(), fco.flags())
    return 0

def copiespathcopies(orig, ctx1, ctx2):
    copies = orig(ctx1, ctx2)
    updated = {}

    for k, v in copies.iteritems():
        updated[lfutil.splitstandin(k) or k] = lfutil.splitstandin(v) or v

    return updated

# Copy first changes the matchers to match standins instead of
# largefiles.  Then it overrides util.copyfile in that function it
# checks if the destination largefile already exists. It also keeps a
# list of copied files so that the largefiles can be copied and the
# dirstate updated.
def overridecopy(orig, ui, repo, pats, opts, rename=False):
    # doesn't remove largefile on rename
    if len(pats) < 2:
        # this isn't legal, let the original function deal with it
        return orig(ui, repo, pats, opts, rename)

    # This could copy both lfiles and normal files in one command,
    # but we don't want to do that. First replace their matcher to
    # only match normal files and run it, then replace it to just
    # match largefiles and run it again.
    nonormalfiles = False
    nolfiles = False
    installnormalfilesmatchfn(repo[None].manifest())
    try:
        try:
            result = orig(ui, repo, pats, opts, rename)
        except util.Abort, e:
            if str(e) != _('no files to copy'):
                raise e
            else:
                nonormalfiles = True
            result = 0
    finally:
        restorematchfn()

    # The first rename can cause our current working directory to be removed.
    # In that case there is nothing left to copy/rename so just quit.
    try:
        repo.getcwd()
    except OSError:
        return result

    def makestandin(relpath):
        path = pathutil.canonpath(repo.root, repo.getcwd(), relpath)
        return os.path.join(repo.wjoin(lfutil.standin(path)))

    fullpats = scmutil.expandpats(pats)
    dest = fullpats[-1]

    if os.path.isdir(dest):
        if not os.path.isdir(makestandin(dest)):
            os.makedirs(makestandin(dest))

    try:
        try:
            # When we call orig below it creates the standins but we don't add
            # them to the dir state until later so lock during that time.
            wlock = repo.wlock()

            manifest = repo[None].manifest()
            def overridematch(ctx, pats=[], opts={}, globbed=False,
                    default='relpath'):
                newpats = []
                # The patterns were previously mangled to add the standin
                # directory; we need to remove that now
                for pat in pats:
                    if match_.patkind(pat) is None and lfutil.shortname in pat:
                        newpats.append(pat.replace(lfutil.shortname, ''))
                    else:
                        newpats.append(pat)
                match = oldmatch(ctx, newpats, opts, globbed, default)
                m = copy.copy(match)
                lfile = lambda f: lfutil.standin(f) in manifest
                m._files = [lfutil.standin(f) for f in m._files if lfile(f)]
                m._fmap = set(m._files)
                origmatchfn = m.matchfn
                m.matchfn = lambda f: (lfutil.isstandin(f) and
                                    (f in manifest) and
                                    origmatchfn(lfutil.splitstandin(f)) or
                                    None)
                return m
            oldmatch = installmatchfn(overridematch)
            listpats = []
            for pat in pats:
                if match_.patkind(pat) is not None:
                    listpats.append(pat)
                else:
                    listpats.append(makestandin(pat))

            try:
                origcopyfile = util.copyfile
                copiedfiles = []
                def overridecopyfile(src, dest):
                    if (lfutil.shortname in src and
                        dest.startswith(repo.wjoin(lfutil.shortname))):
                        destlfile = dest.replace(lfutil.shortname, '')
                        if not opts['force'] and os.path.exists(destlfile):
                            raise IOError('',
                                _('destination largefile already exists'))
                    copiedfiles.append((src, dest))
                    origcopyfile(src, dest)

                util.copyfile = overridecopyfile
                result += orig(ui, repo, listpats, opts, rename)
            finally:
                util.copyfile = origcopyfile

            lfdirstate = lfutil.openlfdirstate(ui, repo)
            for (src, dest) in copiedfiles:
                if (lfutil.shortname in src and
                    dest.startswith(repo.wjoin(lfutil.shortname))):
                    srclfile = src.replace(repo.wjoin(lfutil.standin('')), '')
                    destlfile = dest.replace(repo.wjoin(lfutil.standin('')), '')
                    destlfiledir = os.path.dirname(repo.wjoin(destlfile)) or '.'
                    if not os.path.isdir(destlfiledir):
                        os.makedirs(destlfiledir)
                    if rename:
                        os.rename(repo.wjoin(srclfile), repo.wjoin(destlfile))

                        # The file is gone, but this deletes any empty parent
                        # directories as a side-effect.
                        util.unlinkpath(repo.wjoin(srclfile), True)
                        lfdirstate.remove(srclfile)
                    else:
                        util.copyfile(repo.wjoin(srclfile),
                                      repo.wjoin(destlfile))

                    lfdirstate.add(destlfile)
            lfdirstate.write()
        except util.Abort, e:
            if str(e) != _('no files to copy'):
                raise e
            else:
                nolfiles = True
    finally:
        restorematchfn()
        wlock.release()

    if nolfiles and nonormalfiles:
        raise util.Abort(_('no files to copy'))

    return result

# When the user calls revert, we have to be careful to not revert any
# changes to other largefiles accidentally. This means we have to keep
# track of the largefiles that are being reverted so we only pull down
# the necessary largefiles.
#
# Standins are only updated (to match the hash of largefiles) before
# commits. Update the standins then run the original revert, changing
# the matcher to hit standins instead of largefiles. Based on the
# resulting standins update the largefiles.
def overriderevert(orig, ui, repo, ctx, parents, *pats, **opts):
    # Because we put the standins in a bad state (by updating them)
    # and then return them to a correct state we need to lock to
    # prevent others from changing them in their incorrect state.
    wlock = repo.wlock()
    try:
        lfdirstate = lfutil.openlfdirstate(ui, repo)
        s = lfutil.lfdirstatestatus(lfdirstate, repo)
        lfdirstate.write()
        for lfile in s.modified:
            lfutil.updatestandin(repo, lfutil.standin(lfile))
        for lfile in s.deleted:
            if (os.path.exists(repo.wjoin(lfutil.standin(lfile)))):
                os.unlink(repo.wjoin(lfutil.standin(lfile)))

        oldstandins = lfutil.getstandinsstate(repo)

        def overridematch(mctx, pats=[], opts={}, globbed=False,
                default='relpath'):
            match = oldmatch(mctx, pats, opts, globbed, default)
            m = copy.copy(match)

            # revert supports recursing into subrepos, and though largefiles
            # currently doesn't work correctly in that case, this match is
            # called, so the lfdirstate above may not be the correct one for
            # this invocation of match.
            lfdirstate = lfutil.openlfdirstate(mctx.repo().ui, mctx.repo(),
                                               False)

            def tostandin(f):
                standin = lfutil.standin(f)
                if standin in ctx or standin in mctx:
                    return standin
                elif standin in repo[None] or lfdirstate[f] == 'r':
                    return None
                return f
            m._files = [tostandin(f) for f in m._files]
            m._files = [f for f in m._files if f is not None]
            m._fmap = set(m._files)
            origmatchfn = m.matchfn
            def matchfn(f):
                if lfutil.isstandin(f):
                    return (origmatchfn(lfutil.splitstandin(f)) and
                            (f in ctx or f in mctx))
                return origmatchfn(f)
            m.matchfn = matchfn
            return m
        oldmatch = installmatchfn(overridematch)
        try:
            orig(ui, repo, ctx, parents, *pats, **opts)
        finally:
            restorematchfn()

        newstandins = lfutil.getstandinsstate(repo)
        filelist = lfutil.getlfilestoupdate(oldstandins, newstandins)
        # lfdirstate should be 'normallookup'-ed for updated files,
        # because reverting doesn't touch dirstate for 'normal' files
        # when target revision is explicitly specified: in such case,
        # 'n' and valid timestamp in dirstate doesn't ensure 'clean'
        # of target (standin) file.
        lfcommands.updatelfiles(ui, repo, filelist, printmessage=False,
                                normallookup=True)

    finally:
        wlock.release()

# after pulling changesets, we need to take some extra care to get
# largefiles updated remotely
def overridepull(orig, ui, repo, source=None, **opts):
    revsprepull = len(repo)
    if not source:
        source = 'default'
    repo.lfpullsource = source
    result = orig(ui, repo, source, **opts)
    revspostpull = len(repo)
    lfrevs = opts.get('lfrev', [])
    if opts.get('all_largefiles'):
        lfrevs.append('pulled()')
    if lfrevs and revspostpull > revsprepull:
        numcached = 0
        repo.firstpulled = revsprepull # for pulled() revset expression
        try:
            for rev in scmutil.revrange(repo, lfrevs):
                ui.note(_('pulling largefiles for revision %s\n') % rev)
                (cached, missing) = lfcommands.cachelfiles(ui, repo, rev)
                numcached += len(cached)
        finally:
            del repo.firstpulled
        ui.status(_("%d largefiles cached\n") % numcached)
    return result

def pulledrevsetsymbol(repo, subset, x):
    """``pulled()``
    Changesets that just has been pulled.

    Only available with largefiles from pull --lfrev expressions.

    .. container:: verbose

      Some examples:

      - pull largefiles for all new changesets::

          hg pull -lfrev "pulled()"

      - pull largefiles for all new branch heads::

          hg pull -lfrev "head(pulled()) and not closed()"

    """

    try:
        firstpulled = repo.firstpulled
    except AttributeError:
        raise util.Abort(_("pulled() only available in --lfrev"))
    return revset.baseset([r for r in subset if r >= firstpulled])

def overrideclone(orig, ui, source, dest=None, **opts):
    d = dest
    if d is None:
        d = hg.defaultdest(source)
    if opts.get('all_largefiles') and not hg.islocal(d):
            raise util.Abort(_(
            '--all-largefiles is incompatible with non-local destination %s') %
            d)

    return orig(ui, source, dest, **opts)

def hgclone(orig, ui, opts, *args, **kwargs):
    result = orig(ui, opts, *args, **kwargs)

    if result is not None:
        sourcerepo, destrepo = result
        repo = destrepo.local()

        # If largefiles is required for this repo, permanently enable it locally
        if 'largefiles' in repo.requirements:
            fp = repo.vfs('hgrc', 'a', text=True)
            try:
                fp.write('\n[extensions]\nlargefiles=\n')
            finally:
                fp.close()

        # Caching is implicitly limited to 'rev' option, since the dest repo was
        # truncated at that point.  The user may expect a download count with
        # this option, so attempt whether or not this is a largefile repo.
        if opts.get('all_largefiles'):
            success, missing = lfcommands.downloadlfiles(ui, repo, None)

            if missing != 0:
                return None

    return result

def overriderebase(orig, ui, repo, **opts):
    if not util.safehasattr(repo, '_largefilesenabled'):
        return orig(ui, repo, **opts)

    resuming = opts.get('continue')
    repo._lfcommithooks.append(lfutil.automatedcommithook(resuming))
    repo._lfstatuswriters.append(lambda *msg, **opts: None)
    try:
        return orig(ui, repo, **opts)
    finally:
        repo._lfstatuswriters.pop()
        repo._lfcommithooks.pop()

def overridearchive(orig, repo, dest, node, kind, decode=True, matchfn=None,
            prefix='', mtime=None, subrepos=None):
    # No need to lock because we are only reading history and
    # largefile caches, neither of which are modified.
    lfcommands.cachelfiles(repo.ui, repo, node)

    if kind not in archival.archivers:
        raise util.Abort(_("unknown archive type '%s'") % kind)

    ctx = repo[node]

    if kind == 'files':
        if prefix:
            raise util.Abort(
                _('cannot give prefix when archiving to files'))
    else:
        prefix = archival.tidyprefix(dest, kind, prefix)

    def write(name, mode, islink, getdata):
        if matchfn and not matchfn(name):
            return
        data = getdata()
        if decode:
            data = repo.wwritedata(name, data)
        archiver.addfile(prefix + name, mode, islink, data)

    archiver = archival.archivers[kind](dest, mtime or ctx.date()[0])

    if repo.ui.configbool("ui", "archivemeta", True):
        def metadata():
            base = 'repo: %s\nnode: %s\nbranch: %s\n' % (
                hex(repo.changelog.node(0)), hex(node), ctx.branch())

            tags = ''.join('tag: %s\n' % t for t in ctx.tags()
                           if repo.tagtype(t) == 'global')
            if not tags:
                repo.ui.pushbuffer()
                opts = {'template': '{latesttag}\n{latesttagdistance}',
                        'style': '', 'patch': None, 'git': None}
                cmdutil.show_changeset(repo.ui, repo, opts).show(ctx)
                ltags, dist = repo.ui.popbuffer().split('\n')
                tags = ''.join('latesttag: %s\n' % t for t in ltags.split(':'))
                tags += 'latesttagdistance: %s\n' % dist

            return base + tags

        write('.hg_archival.txt', 0644, False, metadata)

    for f in ctx:
        ff = ctx.flags(f)
        getdata = ctx[f].data
        if lfutil.isstandin(f):
            path = lfutil.findfile(repo, getdata().strip())
            if path is None:
                raise util.Abort(
                    _('largefile %s not found in repo store or system cache')
                    % lfutil.splitstandin(f))
            f = lfutil.splitstandin(f)

            def getdatafn():
                fd = None
                try:
                    fd = open(path, 'rb')
                    return fd.read()
                finally:
                    if fd:
                        fd.close()

            getdata = getdatafn
        write(f, 'x' in ff and 0755 or 0644, 'l' in ff, getdata)

    if subrepos:
        for subpath in sorted(ctx.substate):
            sub = ctx.sub(subpath)
            submatch = match_.narrowmatcher(subpath, matchfn)
            sub.archive(archiver, prefix, submatch)

    archiver.done()

def hgsubrepoarchive(orig, repo, archiver, prefix, match=None):
    repo._get(repo._state + ('hg',))
    rev = repo._state[1]
    ctx = repo._repo[rev]

    lfcommands.cachelfiles(repo.ui, repo._repo, ctx.node())

    def write(name, mode, islink, getdata):
        # At this point, the standin has been replaced with the largefile name,
        # so the normal matcher works here without the lfutil variants.
        if match and not match(f):
            return
        data = getdata()

        archiver.addfile(prefix + repo._path + '/' + name, mode, islink, data)

    for f in ctx:
        ff = ctx.flags(f)
        getdata = ctx[f].data
        if lfutil.isstandin(f):
            path = lfutil.findfile(repo._repo, getdata().strip())
            if path is None:
                raise util.Abort(
                    _('largefile %s not found in repo store or system cache')
                    % lfutil.splitstandin(f))
            f = lfutil.splitstandin(f)

            def getdatafn():
                fd = None
                try:
                    fd = open(os.path.join(prefix, path), 'rb')
                    return fd.read()
                finally:
                    if fd:
                        fd.close()

            getdata = getdatafn

        write(f, 'x' in ff and 0755 or 0644, 'l' in ff, getdata)

    for subpath in sorted(ctx.substate):
        sub = ctx.sub(subpath)
        submatch = match_.narrowmatcher(subpath, match)
        sub.archive(archiver, os.path.join(prefix, repo._path) + '/', submatch)

# If a largefile is modified, the change is not reflected in its
# standin until a commit. cmdutil.bailifchanged() raises an exception
# if the repo has uncommitted changes. Wrap it to also check if
# largefiles were changed. This is used by bisect, backout and fetch.
def overridebailifchanged(orig, repo, *args, **kwargs):
    orig(repo, *args, **kwargs)
    repo.lfstatus = True
    s = repo.status()
    repo.lfstatus = False
    if s.modified or s.added or s.removed or s.deleted:
        raise util.Abort(_('uncommitted changes'))

def cmdutilforget(orig, ui, repo, match, prefix, explicitonly):
    normalmatcher = composenormalfilematcher(match, repo[None].manifest())
    bad, forgot = orig(ui, repo, normalmatcher, prefix, explicitonly)
    m = composelargefilematcher(match, repo[None].manifest())

    try:
        repo.lfstatus = True
        s = repo.status(match=m, clean=True)
    finally:
        repo.lfstatus = False
    forget = sorted(s.modified + s.added + s.deleted + s.clean)
    forget = [f for f in forget if lfutil.standin(f) in repo[None].manifest()]

    for f in forget:
        if lfutil.standin(f) not in repo.dirstate and not \
                repo.wvfs.isdir(lfutil.standin(f)):
            ui.warn(_('not removing %s: file is already untracked\n')
                    % m.rel(f))
            bad.append(f)

    for f in forget:
        if ui.verbose or not m.exact(f):
            ui.status(_('removing %s\n') % m.rel(f))

    # Need to lock because standin files are deleted then removed from the
    # repository and we could race in-between.
    wlock = repo.wlock()
    try:
        lfdirstate = lfutil.openlfdirstate(ui, repo)
        for f in forget:
            if lfdirstate[f] == 'a':
                lfdirstate.drop(f)
            else:
                lfdirstate.remove(f)
        lfdirstate.write()
        standins = [lfutil.standin(f) for f in forget]
        for f in standins:
            util.unlinkpath(repo.wjoin(f), ignoremissing=True)
        rejected = repo[None].forget(standins)
    finally:
        wlock.release()

    bad.extend(f for f in rejected if f in m.files())
    forgot.extend(f for f in forget if f not in rejected)
    return bad, forgot

def _getoutgoings(repo, other, missing, addfunc):
    """get pairs of filename and largefile hash in outgoing revisions
    in 'missing'.

    largefiles already existing on 'other' repository are ignored.

    'addfunc' is invoked with each unique pairs of filename and
    largefile hash value.
    """
    knowns = set()
    lfhashes = set()
    def dedup(fn, lfhash):
        k = (fn, lfhash)
        if k not in knowns:
            knowns.add(k)
            lfhashes.add(lfhash)
    lfutil.getlfilestoupload(repo, missing, dedup)
    if lfhashes:
        lfexists = basestore._openstore(repo, other).exists(lfhashes)
        for fn, lfhash in knowns:
            if not lfexists[lfhash]: # lfhash doesn't exist on "other"
                addfunc(fn, lfhash)

def outgoinghook(ui, repo, other, opts, missing):
    if opts.pop('large', None):
        lfhashes = set()
        if ui.debugflag:
            toupload = {}
            def addfunc(fn, lfhash):
                if fn not in toupload:
                    toupload[fn] = []
                toupload[fn].append(lfhash)
                lfhashes.add(lfhash)
            def showhashes(fn):
                for lfhash in sorted(toupload[fn]):
                    ui.debug('    %s\n' % (lfhash))
        else:
            toupload = set()
            def addfunc(fn, lfhash):
                toupload.add(fn)
                lfhashes.add(lfhash)
            def showhashes(fn):
                pass
        _getoutgoings(repo, other, missing, addfunc)

        if not toupload:
            ui.status(_('largefiles: no files to upload\n'))
        else:
            ui.status(_('largefiles to upload (%d entities):\n')
                      % (len(lfhashes)))
            for file in sorted(toupload):
                ui.status(lfutil.splitstandin(file) + '\n')
                showhashes(file)
            ui.status('\n')

def summaryremotehook(ui, repo, opts, changes):
    largeopt = opts.get('large', False)
    if changes is None:
        if largeopt:
            return (False, True) # only outgoing check is needed
        else:
            return (False, False)
    elif largeopt:
        url, branch, peer, outgoing = changes[1]
        if peer is None:
            # i18n: column positioning for "hg summary"
            ui.status(_('largefiles: (no remote repo)\n'))
            return

        toupload = set()
        lfhashes = set()
        def addfunc(fn, lfhash):
            toupload.add(fn)
            lfhashes.add(lfhash)
        _getoutgoings(repo, peer, outgoing.missing, addfunc)

        if not toupload:
            # i18n: column positioning for "hg summary"
            ui.status(_('largefiles: (no files to upload)\n'))
        else:
            # i18n: column positioning for "hg summary"
            ui.status(_('largefiles: %d entities for %d files to upload\n')
                      % (len(lfhashes), len(toupload)))

def overridesummary(orig, ui, repo, *pats, **opts):
    try:
        repo.lfstatus = True
        orig(ui, repo, *pats, **opts)
    finally:
        repo.lfstatus = False

def scmutiladdremove(orig, repo, matcher, prefix, opts={}, dry_run=None,
                     similarity=None):
    if not lfutil.islfilesrepo(repo):
        return orig(repo, matcher, prefix, opts, dry_run, similarity)
    # Get the list of missing largefiles so we can remove them
    lfdirstate = lfutil.openlfdirstate(repo.ui, repo)
    unsure, s = lfdirstate.status(match_.always(repo.root, repo.getcwd()), [],
                                  False, False, False)

    # Call into the normal remove code, but the removing of the standin, we want
    # to have handled by original addremove.  Monkey patching here makes sure
    # we don't remove the standin in the largefiles code, preventing a very
    # confused state later.
    if s.deleted:
        m = copy.copy(matcher)

        # The m._files and m._map attributes are not changed to the deleted list
        # because that affects the m.exact() test, which in turn governs whether
        # or not the file name is printed, and how.  Simply limit the original
        # matches to those in the deleted status list.
        matchfn = m.matchfn
        m.matchfn = lambda f: f in s.deleted and matchfn(f)

        removelargefiles(repo.ui, repo, True, m, **opts)
    # Call into the normal add code, and any files that *should* be added as
    # largefiles will be
    added, bad = addlargefiles(repo.ui, repo, True, matcher, **opts)
    # Now that we've handled largefiles, hand off to the original addremove
    # function to take care of the rest.  Make sure it doesn't do anything with
    # largefiles by passing a matcher that will ignore them.
    matcher = composenormalfilematcher(matcher, repo[None].manifest(), added)
    return orig(repo, matcher, prefix, opts, dry_run, similarity)

# Calling purge with --all will cause the largefiles to be deleted.
# Override repo.status to prevent this from happening.
def overridepurge(orig, ui, repo, *dirs, **opts):
    # XXX Monkey patching a repoview will not work. The assigned attribute will
    # be set on the unfiltered repo, but we will only lookup attributes in the
    # unfiltered repo if the lookup in the repoview object itself fails. As the
    # monkey patched method exists on the repoview class the lookup will not
    # fail. As a result, the original version will shadow the monkey patched
    # one, defeating the monkey patch.
    #
    # As a work around we use an unfiltered repo here. We should do something
    # cleaner instead.
    repo = repo.unfiltered()
    oldstatus = repo.status
    def overridestatus(node1='.', node2=None, match=None, ignored=False,
                        clean=False, unknown=False, listsubrepos=False):
        r = oldstatus(node1, node2, match, ignored, clean, unknown,
                      listsubrepos)
        lfdirstate = lfutil.openlfdirstate(ui, repo)
        unknown = [f for f in r.unknown if lfdirstate[f] == '?']
        ignored = [f for f in r.ignored if lfdirstate[f] == '?']
        return scmutil.status(r.modified, r.added, r.removed, r.deleted,
                              unknown, ignored, r.clean)
    repo.status = overridestatus
    orig(ui, repo, *dirs, **opts)
    repo.status = oldstatus
def overriderollback(orig, ui, repo, **opts):
    wlock = repo.wlock()
    try:
        before = repo.dirstate.parents()
        orphans = set(f for f in repo.dirstate
                      if lfutil.isstandin(f) and repo.dirstate[f] != 'r')
        result = orig(ui, repo, **opts)
        after = repo.dirstate.parents()
        if before == after:
            return result # no need to restore standins

        pctx = repo['.']
        for f in repo.dirstate:
            if lfutil.isstandin(f):
                orphans.discard(f)
                if repo.dirstate[f] == 'r':
                    repo.wvfs.unlinkpath(f, ignoremissing=True)
                elif f in pctx:
                    fctx = pctx[f]
                    repo.wwrite(f, fctx.data(), fctx.flags())
                else:
                    # content of standin is not so important in 'a',
                    # 'm' or 'n' (coming from the 2nd parent) cases
                    lfutil.writestandin(repo, f, '', False)
        for standin in orphans:
            repo.wvfs.unlinkpath(standin, ignoremissing=True)

        lfdirstate = lfutil.openlfdirstate(ui, repo)
        orphans = set(lfdirstate)
        lfiles = lfutil.listlfiles(repo)
        for file in lfiles:
            lfutil.synclfdirstate(repo, lfdirstate, file, True)
            orphans.discard(file)
        for lfile in orphans:
            lfdirstate.drop(lfile)
        lfdirstate.write()
    finally:
        wlock.release()
    return result

def overridetransplant(orig, ui, repo, *revs, **opts):
    resuming = opts.get('continue')
    repo._lfcommithooks.append(lfutil.automatedcommithook(resuming))
    repo._lfstatuswriters.append(lambda *msg, **opts: None)
    try:
        result = orig(ui, repo, *revs, **opts)
    finally:
        repo._lfstatuswriters.pop()
        repo._lfcommithooks.pop()
    return result

def overridecat(orig, ui, repo, file1, *pats, **opts):
    ctx = scmutil.revsingle(repo, opts.get('rev'))
    err = 1
    notbad = set()
    m = scmutil.match(ctx, (file1,) + pats, opts)
    origmatchfn = m.matchfn
    def lfmatchfn(f):
        if origmatchfn(f):
            return True
        lf = lfutil.splitstandin(f)
        if lf is None:
            return False
        notbad.add(lf)
        return origmatchfn(lf)
    m.matchfn = lfmatchfn
    origbadfn = m.bad
    def lfbadfn(f, msg):
        if not f in notbad:
            origbadfn(f, msg)
    m.bad = lfbadfn

    origvisitdirfn = m.visitdir
    def lfvisitdirfn(dir):
        if dir == lfutil.shortname:
            return True
        ret = origvisitdirfn(dir)
        if ret:
            return ret
        lf = lfutil.splitstandin(dir)
        if lf is None:
            return False
        return origvisitdirfn(lf)
    m.visitdir = lfvisitdirfn

    for f in ctx.walk(m):
        fp = cmdutil.makefileobj(repo, opts.get('output'), ctx.node(),
                                 pathname=f)
        lf = lfutil.splitstandin(f)
        if lf is None or origmatchfn(f):
            # duplicating unreachable code from commands.cat
            data = ctx[f].data()
            if opts.get('decode'):
                data = repo.wwritedata(f, data)
            fp.write(data)
        else:
            hash = lfutil.readstandin(repo, lf, ctx.rev())
            if not lfutil.inusercache(repo.ui, hash):
                store = basestore._openstore(repo)
                success, missing = store.get([(lf, hash)])
                if len(success) != 1:
                    raise util.Abort(
                        _('largefile %s is not in cache and could not be '
                          'downloaded')  % lf)
            path = lfutil.usercachepath(repo.ui, hash)
            fpin = open(path, "rb")
            for chunk in util.filechunkiter(fpin, 128 * 1024):
                fp.write(chunk)
            fpin.close()
        fp.close()
        err = 0
    return err

def mergeupdate(orig, repo, node, branchmerge, force, partial,
                *args, **kwargs):
    wlock = repo.wlock()
    try:
        # branch |       |         |
        #  merge | force | partial | action
        # -------+-------+---------+--------------
        #    x   |   x   |    x    | linear-merge
        #    o   |   x   |    x    | branch-merge
        #    x   |   o   |    x    | overwrite (as clean update)
        #    o   |   o   |    x    | force-branch-merge (*1)
        #    x   |   x   |    o    |   (*)
        #    o   |   x   |    o    |   (*)
        #    x   |   o   |    o    | overwrite (as revert)
        #    o   |   o   |    o    |   (*)
        #
        # (*) don't care
        # (*1) deprecated, but used internally (e.g: "rebase --collapse")

        linearmerge = not branchmerge and not force and not partial

        if linearmerge or (branchmerge and force and not partial):
            # update standins for linear-merge or force-branch-merge,
            # because largefiles in the working directory may be modified
            lfdirstate = lfutil.openlfdirstate(repo.ui, repo)
            unsure, s = lfdirstate.status(match_.always(repo.root,
                                                        repo.getcwd()),
                                          [], False, False, False)
            pctx = repo['.']
            for lfile in unsure + s.modified:
                lfileabs = repo.wvfs.join(lfile)
                if not os.path.exists(lfileabs):
                    continue
                lfhash = lfutil.hashrepofile(repo, lfile)
                standin = lfutil.standin(lfile)
                lfutil.writestandin(repo, standin, lfhash,
                                    lfutil.getexecutable(lfileabs))
                if (standin in pctx and
                    lfhash == lfutil.readstandin(repo, lfile, '.')):
                    lfdirstate.normal(lfile)
            for lfile in s.added:
                lfutil.updatestandin(repo, lfutil.standin(lfile))
            lfdirstate.write()

        if linearmerge:
            # Only call updatelfiles on the standins that have changed
            # to save time
            oldstandins = lfutil.getstandinsstate(repo)

        result = orig(repo, node, branchmerge, force, partial, *args, **kwargs)

        filelist = None
        if linearmerge:
            newstandins = lfutil.getstandinsstate(repo)
            filelist = lfutil.getlfilestoupdate(oldstandins, newstandins)

        lfcommands.updatelfiles(repo.ui, repo, filelist=filelist,
                                normallookup=partial, checked=linearmerge)

        return result
    finally:
        wlock.release()

def scmutilmarktouched(orig, repo, files, *args, **kwargs):
    result = orig(repo, files, *args, **kwargs)

    filelist = [lfutil.splitstandin(f) for f in files if lfutil.isstandin(f)]
    if filelist:
        lfcommands.updatelfiles(repo.ui, repo, filelist=filelist,
                                printmessage=False, normallookup=True)

    return result