# shelve.py - save/restore working directory state

#

# Copyright 2013 Facebook, Inc.

#

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

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

"""save and restore changes to the working directory

The "hg shelve" command saves changes made to the working directory

and reverts those changes, resetting the working directory to a clean

state.

Later on, the "hg unshelve" command restores the changes saved by "hg

shelve". Changes can be restored even after updating to a different

parent, in which case Mercurial's merge machinery will resolve any

conflicts if necessary.

You can have more than one shelved change outstanding at a time; each

shelved change has a distinct name. For details, see the help for "hg

shelve".

"""

from __future__ import absolute_import

import collections

import errno

import itertools

import stat

from .i18n import _

from .pycompat import open

from . import (

    bookmarks,

    bundle2,

    bundlerepo,

    changegroup,

    cmdutil,

    discovery,

    error,

    exchange,

    hg,

    lock as lockmod,

    mdiff,

    merge,

    mergestate as mergestatemod,

    node as nodemod,

    patch,

    phases,

    pycompat,

    repair,

    scmutil,

    templatefilters,

    util,

    vfs as vfsmod,

)

from .utils import (

    dateutil,

    stringutil,

)

backupdir = b'shelve-backup'

shelvedir = b'shelved'

shelvefileextensions = [b'hg', b'patch', b'shelve']

# universal extension is present in all types of shelves

patchextension = b'patch'

# we never need the user, so we use a

# generic user for all shelve operations

shelveuser = b'shelve@localhost'

class shelvedfile(object):

    """Helper for the file storing a single shelve

    Handles common functions on shelve files (.hg/.patch) using

    the vfs layer"""

    def __init__(self, repo, name, filetype=None):

        self.repo = repo

        self.name = name

        self.vfs = vfsmod.vfs(repo.vfs.join(shelvedir))

        self.backupvfs = vfsmod.vfs(repo.vfs.join(backupdir))

        self.ui = self.repo.ui

        if filetype:

            self.fname = name + b'.' + filetype

        else:

            self.fname = name

    def exists(self):

        return self.vfs.exists(self.fname)

    def filename(self):

        return self.vfs.join(self.fname)

    def backupfilename(self):

        def gennames(base):

            yield base

            base, ext = base.rsplit(b'.', 1)

            for i in itertools.count(1):

                yield b'%s-%d.%s' % (base, i, ext)

        name = self.backupvfs.join(self.fname)

        for n in gennames(name):

            if not self.backupvfs.exists(n):

                return n

    def movetobackup(self):

        if not self.backupvfs.isdir():

            self.backupvfs.makedir()

        util.rename(self.filename(), self.backupfilename())

    def stat(self):

        return self.vfs.stat(self.fname)

    def opener(self, mode=b'rb'):

        try:

            return self.vfs(self.fname, mode)

        except IOError as err:

            if err.errno != errno.ENOENT:

                raise

            raise error.Abort(_(b"shelved change '%s' not found") % self.name)

    def applybundle(self, tr):

        fp = self.opener()

        try:

            targetphase = phases.internal

            if not phases.supportinternal(self.repo):

                targetphase = phases.secret

            gen = exchange.readbundle(self.repo.ui, fp, self.fname, self.vfs)

            pretip = self.repo[b'tip']

            bundle2.applybundle(

                self.repo,

                gen,

                tr,

                source=b'unshelve',

                url=b'bundle:' + self.vfs.join(self.fname),

                targetphase=targetphase,

            )

            shelvectx = self.repo[b'tip']

            if pretip == shelvectx:

                shelverev = tr.changes[b'revduplicates'][-1]

                shelvectx = self.repo[shelverev]

            return shelvectx

        finally:

            fp.close()

    def bundlerepo(self):

        path = self.vfs.join(self.fname)

        return bundlerepo.instance(

            self.repo.baseui, b'bundle://%s+%s' % (self.repo.root, path), False

        )

    def writebundle(self, bases, node):

        cgversion = changegroup.safeversion(self.repo)

        if cgversion == b'01':

            btype = b'HG10BZ'

            compression = None

        else:

            btype = b'HG20'

            compression = b'BZ'

        repo = self.repo.unfiltered()

        outgoing = discovery.outgoing(

            repo, missingroots=bases, ancestorsof=[node]

        )

        cg = changegroup.makechangegroup(repo, outgoing, cgversion, b'shelve')

        bundle2.writebundle(

            self.ui, cg, self.fname, btype, self.vfs, compression=compression

        )

    def writeinfo(self, info):

        scmutil.simplekeyvaluefile(self.vfs, self.fname).write(info)

    def readinfo(self):

        return scmutil.simplekeyvaluefile(self.vfs, self.fname).read()

class shelvedstate(object):

    """Handle persistence during unshelving operations.

    Handles saving and restoring a shelved state. Ensures that different

    versions of a shelved state are possible and handles them appropriately.

    """

    _version = 2

    _filename = b'shelvedstate'

    _keep = b'keep'

    _nokeep = b'nokeep'

    # colon is essential to differentiate from a real bookmark name

    _noactivebook = b':no-active-bookmark'

    _interactive = b'interactive'

    @classmethod

    def _verifyandtransform(cls, d):

        """Some basic shelvestate syntactic verification and transformation"""

        try:

            d[b'originalwctx'] = nodemod.bin(d[b'originalwctx'])

            d[b'pendingctx'] = nodemod.bin(d[b'pendingctx'])

            d[b'parents'] = [nodemod.bin(h) for h in d[b'parents'].split(b' ')]

            d[b'nodestoremove'] = [

                nodemod.bin(h) for h in d[b'nodestoremove'].split(b' ')

            ]

        except (ValueError, TypeError, KeyError) as err:

            raise error.CorruptedState(pycompat.bytestr(err))

    @classmethod

    def _getversion(cls, repo):

        """Read version information from shelvestate file"""

        fp = repo.vfs(cls._filename)

        try:

            version = int(fp.readline().strip())

        except ValueError as err:

            raise error.CorruptedState(pycompat.bytestr(err))

        finally:

            fp.close()

        return version

    @classmethod

    def _readold(cls, repo):

        """Read the old position-based version of a shelvestate file"""

        # Order is important, because old shelvestate file uses it

        # to detemine values of fields (i.g. name is on the second line,

        # originalwctx is on the third and so forth). Please do not change.

        keys = [

            b'version',

            b'name',

            b'originalwctx',

            b'pendingctx',

            b'parents',

            b'nodestoremove',

            b'branchtorestore',

            b'keep',

            b'activebook',

        ]

        # this is executed only seldomly, so it is not a big deal

        # that we open this file twice

        fp = repo.vfs(cls._filename)

        d = {}

        try:

            for key in keys:

                d[key] = fp.readline().strip()

        finally:

            fp.close()

        return d

    @classmethod

    def load(cls, repo):

        version = cls._getversion(repo)

        if version < cls._version:

            d = cls._readold(repo)

        elif version == cls._version:

            d = scmutil.simplekeyvaluefile(repo.vfs, cls._filename).read(

                firstlinenonkeyval=True

            )

        else:

            raise error.Abort(

                _(

                    b'this version of shelve is incompatible '

                    b'with the version used in this repo'

                )

            )

        cls._verifyandtransform(d)

        try:

            obj = cls()

            obj.name = d[b'name']

            obj.wctx = repo[d[b'originalwctx']]

            obj.pendingctx = repo[d[b'pendingctx']]

            obj.parents = d[b'parents']

            obj.nodestoremove = d[b'nodestoremove']

            obj.branchtorestore = d.get(b'branchtorestore', b'')

            obj.keep = d.get(b'keep') == cls._keep

            obj.activebookmark = b''

            if d.get(b'activebook', b'') != cls._noactivebook:

                obj.activebookmark = d.get(b'activebook', b'')

            obj.interactive = d.get(b'interactive') == cls._interactive

        except (error.RepoLookupError, KeyError) as err:

            raise error.CorruptedState(pycompat.bytestr(err))

        return obj

    @classmethod

    def save(

        cls,

        repo,

        name,

        originalwctx,

        pendingctx,

        nodestoremove,

        branchtorestore,

        keep=False,

        activebook=b'',

        interactive=False,

    ):

        info = {

            b"name": name,

            b"originalwctx": nodemod.hex(originalwctx.node()),

            b"pendingctx": nodemod.hex(pendingctx.node()),

            b"parents": b' '.join(

                [nodemod.hex(p) for p in repo.dirstate.parents()]

            ),

            b"nodestoremove": b' '.join(

                [nodemod.hex(n) for n in nodestoremove]

            ),

            b"branchtorestore": branchtorestore,

            b"keep": cls._keep if keep else cls._nokeep,

            b"activebook": activebook or cls._noactivebook,

        }

        if interactive:

            info[b'interactive'] = cls._interactive

        scmutil.simplekeyvaluefile(repo.vfs, cls._filename).write(

            info, firstline=(b"%d" % cls._version)

        )

    @classmethod

    def clear(cls, repo):

        repo.vfs.unlinkpath(cls._filename, ignoremissing=True)

def cleanupoldbackups(repo):

    vfs = vfsmod.vfs(repo.vfs.join(backupdir))

    maxbackups = repo.ui.configint(b'shelve', b'maxbackups')

    hgfiles = [f for f in vfs.listdir() if f.endswith(b'.' + patchextension)]

    hgfiles = sorted([(vfs.stat(f)[stat.ST_MTIME], f) for f in hgfiles])

    if maxbackups > 0 and maxbackups < len(hgfiles):

        bordermtime = hgfiles[-maxbackups][0]

    else:

        bordermtime = None

    for mtime, f in hgfiles[: len(hgfiles) - maxbackups]:

        if mtime == bordermtime:

            # keep it, because timestamp can't decide exact order of backups

            continue

        base = f[: -(1 + len(patchextension))]

        for ext in shelvefileextensions:

            vfs.tryunlink(base + b'.' + ext)

def _backupactivebookmark(repo):

    activebookmark = repo._activebookmark

    if activebookmark:

        bookmarks.deactivate(repo)

    return activebookmark

def _restoreactivebookmark(repo, mark):

    if mark:

        bookmarks.activate(repo, mark)

def _aborttransaction(repo, tr):

    '''Abort current transaction for shelve/unshelve, but keep dirstate

    '''

    dirstatebackupname = b'dirstate.shelve'

    repo.dirstate.savebackup(tr, dirstatebackupname)

    tr.abort()

    repo.dirstate.restorebackup(None, dirstatebackupname)

def getshelvename(repo, parent, opts):

    """Decide on the name this shelve is going to have"""

    def gennames():

        yield label

        for i in itertools.count(1):

            yield b'%s-%02d' % (label, i)

    name = opts.get(b'name')

    label = repo._activebookmark or parent.branch() or b'default'

    # slashes aren't allowed in filenames, therefore we rename it

    label = label.replace(b'/', b'_')

    label = label.replace(b'\\', b'_')