# -*- coding: utf-8 -*-
'''
Mercurial Fileserver Backend

To enable, add ``hgfs`` to the :conf_master:`fileserver_backend` option in the
Master config file.

.. code-block:: yaml

    fileserver_backend:
      - hgfs

.. note::
    ``hg`` also works here. Prior to the 2018.3.0 release, *only* ``hg`` would
    work.

After enabling this backend, branches, bookmarks, and tags in a remote
mercurial repository are exposed to salt as different environments. This
feature is managed by the :conf_master:`fileserver_backend` option in the salt
master config file.

This fileserver has an additional option :conf_master:`hgfs_branch_method` that
will set the desired branch method. Possible values are: ``branches``,
``bookmarks``, or ``mixed``. If using ``branches`` or ``mixed``, the
``default`` branch will be mapped to ``base``.


.. versionchanged:: 2014.1.0
    The :conf_master:`hgfs_base` master config parameter was added, allowing
    for a branch other than ``default`` to be used for the ``base``
    environment, and allowing for a ``base`` environment to be specified when
    using an :conf_master:`hgfs_branch_method` of ``bookmarks``.


:depends:   - mercurial
            - python bindings for mercurial (``python-hglib``)
'''

# Import python libs
from __future__ import absolute_import, print_function, unicode_literals
import copy
import errno
import fnmatch
import glob
import hashlib
import logging
import os
import shutil
from datetime import datetime
from salt.exceptions import FileserverConfigError

VALID_BRANCH_METHODS = ('branches', 'bookmarks', 'mixed')
PER_REMOTE_OVERRIDES = ('base', 'branch_method', 'mountpoint', 'root')

# Import third party libs
from salt.ext import six
# pylint: disable=import-error
try:
    import hglib
    HAS_HG = True
except ImportError:
    HAS_HG = False
# pylint: enable=import-error

# Import salt libs
import salt.utils.data
import salt.utils.files
import salt.utils.gzip_util
import salt.utils.hashutils
import salt.utils.stringutils
import salt.utils.url
import salt.utils.versions
import salt.fileserver
from salt.utils.event import tagify

log = logging.getLogger(__name__)

# Define the module's virtual name
__virtualname__ = 'hg'


def __virtual__():
    '''
    Only load if mercurial is available
    '''
    if __virtualname__ not in __opts__['fileserver_backend']:
        return False
    if not HAS_HG:
        log.error('Mercurial fileserver backend is enabled in configuration '
                  'but could not be loaded, is hglib installed?')
        return False
    if __opts__['hgfs_branch_method'] not in VALID_BRANCH_METHODS:
        log.error(
            'Invalid hgfs_branch_method \'%s\'. Valid methods are: %s',
            __opts__['hgfs_branch_method'], VALID_BRANCH_METHODS
        )
        return False
    return __virtualname__


def _all_branches(repo):
    '''
    Returns all branches for the specified repo
    '''
    # repo.branches() returns a list of 3-tuples consisting of
    # (branch name, rev #, nodeid)
    # Example: [('default', 4, '7c96229269fa')]
    return repo.branches()


def _get_branch(repo, name):
    '''
    Find the requested branch in the specified repo
    '''
    try:
        return [x for x in _all_branches(repo) if x[0] == name][0]
    except IndexError:
        return False


def _all_bookmarks(repo):
    '''
    Returns all bookmarks for the specified repo
    '''
    # repo.bookmarks() returns a tuple containing the following:
    #   1. A list of 3-tuples consisting of (bookmark name, rev #, nodeid)
    #   2. The index of the current bookmark (-1 if no current one)
    # Example: ([('mymark', 4, '7c96229269fa')], -1)
    return repo.bookmarks()[0]


def _get_bookmark(repo, name):
    '''
    Find the requested bookmark in the specified repo
    '''
    try:
        return [x for x in _all_bookmarks(repo) if x[0] == name][0]
    except IndexError:
        return False


def _all_tags(repo):
    '''
    Returns all tags for the specified repo
    '''
    # repo.tags() returns a list of 4-tuples consisting of
    # (tag name, rev #, nodeid, islocal)
    # Example: [('1.0', 3, '3be15e71b31a', False),
    #           ('tip', 4, '7c96229269fa', False)]
    # Avoid returning the special 'tip' tag.
    return [x for x in repo.tags() if x[0] != 'tip']


def _get_tag(repo, name):
    '''
    Find the requested tag in the specified repo
    '''
    try:
        return [x for x in _all_tags(repo) if x[0] == name][0]
    except IndexError:
        return False


def _get_ref(repo, name):
    '''
    Return ref tuple if ref is in the repo.
    '''
    if name == 'base':
        name = repo['base']
    if name == repo['base'] or name in envs():
        if repo['branch_method'] == 'branches':
            return _get_branch(repo['repo'], name) \
                or _get_tag(repo['repo'], name)
        elif repo['branch_method'] == 'bookmarks':
            return _get_bookmark(repo['repo'], name) \
                or _get_tag(repo['repo'], name)
        elif repo['branch_method'] == 'mixed':
            return _get_branch(repo['repo'], name) \
                or _get_bookmark(repo['repo'], name) \
                or _get_tag(repo['repo'], name)
    return False


def _failhard():
    '''
    Fatal fileserver configuration issue, raise an exception
    '''
    raise FileserverConfigError(
        'Failed to load hg fileserver backend'
    )


def init():
    '''
    Return a list of hglib objects for the various hgfs remotes
    '''
    bp_ = os.path.join(__opts__['cachedir'], 'hgfs')
    new_remote = False
    repos = []

    per_remote_defaults = {}
    for param in PER_REMOTE_OVERRIDES:
        per_remote_defaults[param] = \
            six.text_type(__opts__['hgfs_{0}'.format(param)])

    for remote in __opts__['hgfs_remotes']:
        repo_conf = copy.deepcopy(per_remote_defaults)
        if isinstance(remote, dict):
            repo_url = next(iter(remote))
            per_remote_conf = dict(
                [(key, six.text_type(val)) for key, val in
                 six.iteritems(salt.utils.data.repack_dictlist(remote[repo_url]))]
            )
            if not per_remote_conf:
                log.error(
                    'Invalid per-remote configuration for hgfs remote %s. If '
                    'no per-remote parameters are being specified, there may '
                    'be a trailing colon after the URL, which should be '
                    'removed. Check the master configuration file.', repo_url
                )
                _failhard()

            branch_method = \
                per_remote_conf.get('branch_method',
                                    per_remote_defaults['branch_method'])
            if branch_method not in VALID_BRANCH_METHODS:
                log.error(
                    'Invalid branch_method \'%s\' for remote %s. Valid '
                    'branch methods are: %s. This remote will be ignored.',
                    branch_method, repo_url, ', '.join(VALID_BRANCH_METHODS)
                )
                _failhard()

            per_remote_errors = False
            for param in (x for x in per_remote_conf
                          if x not in PER_REMOTE_OVERRIDES):
                log.error(
                    'Invalid configuration parameter \'%s\' for remote %s. '
                    'Valid parameters are: %s. See the documentation for '
                    'further information.',
                    param, repo_url, ', '.join(PER_REMOTE_OVERRIDES)
                )
                per_remote_errors = True
            if per_remote_errors:
                _failhard()

            repo_conf.update(per_remote_conf)
        else:
            repo_url = remote

        if not isinstance(repo_url, six.string_types):
            log.error(
                'Invalid hgfs remote %s. Remotes must be strings, you may '
                'need to enclose the URL in quotes', repo_url
            )
            _failhard()

        try:
            repo_conf['mountpoint'] = salt.utils.url.strip_proto(
                repo_conf['mountpoint']
            )
        except TypeError:
            # mountpoint not specified
            pass

        hash_type = getattr(hashlib, __opts__.get('hash_type', 'md5'))
        repo_hash = hash_type(repo_url).hexdigest()
        rp_ = os.path.join(bp_, repo_hash)
        if not os.path.isdir(rp_):
            os.makedirs(rp_)

        if not os.listdir(rp_):
            # Only init if the directory is empty.
            hglib.init(rp_)
            new_remote = True
        try:
            repo = hglib.open(rp_)
        except hglib.error.ServerError:
            log.error(
                'Cache path %s (corresponding remote: %s) exists but is not '
                'a valid mercurial repository. You will need to manually '
                'delete this directory on the master to continue to use this '
                'hgfs remote.', rp_, repo_url
            )
            _failhard()
        except Exception as exc:  # pylint: disable=broad-except
            log.error(
                'Exception \'%s\' encountered while initializing hgfs '
                'remote %s', exc, repo_url
            )
            _failhard()

        try:
            refs = repo.config(names='paths')
        except hglib.error.CommandError:
            refs = None

        # Do NOT put this if statement inside the except block above. Earlier
        # versions of hglib did not raise an exception, so we need to do it
        # this way to support both older and newer hglib.
        if not refs:
            # Write an hgrc defining the remote URL
            hgconfpath = os.path.join(rp_, '.hg', 'hgrc')
            with salt.utils.files.fopen(hgconfpath, 'w+') as hgconfig:
                hgconfig.write('[paths]\n')
                hgconfig.write(
                    salt.utils.stringutils.to_str(
                        'default = {0}\n'.format(repo_url)
                    )
                )

        repo_conf.update({
            'repo': repo,
            'url': repo_url,
            'hash': repo_hash,
            'cachedir': rp_,
            'lockfile': os.path.join(__opts__['cachedir'],
                                     'hgfs',
                                     '{0}.update.lk'.format(repo_hash))
        })
        repos.append(repo_conf)
        repo.close()

    if new_remote:
        remote_map = os.path.join(__opts__['cachedir'], 'hgfs/remote_map.txt')
        try:
            with salt.utils.files.fopen(remote_map, 'w+') as fp_:
                timestamp = datetime.now().strftime('%d %b %Y %H:%M:%S.%f')
                fp_.write('# hgfs_remote map as of {0}\n'.format(timestamp))
                for repo in repos:
                    fp_.write(
                        salt.utils.stringutils.to_str(
                            '{0} = {1}\n'.format(repo['hash'], repo['url'])
                        )
                    )
        except OSError:
            pass
        else:
            log.info('Wrote new hgfs_remote map to %s', remote_map)

    return repos


def _clear_old_remotes():
    '''
    Remove cache directories for remotes no longer configured
    '''
    bp_ = os.path.join(__opts__['cachedir'], 'hgfs')
    try:
        cachedir_ls = os.listdir(bp_)
    except OSError:
        cachedir_ls = []
    repos = init()
    # Remove actively-used remotes from list
    for repo in repos:
        try:
            cachedir_ls.remove(repo['hash'])
        except ValueError:
            pass
    to_remove = []
    for item in cachedir_ls:
        if item in ('hash', 'refs'):
            continue
        path = os.path.join(bp_, item)
        if os.path.isdir(path):
            to_remove.append(path)
    failed = []
    if to_remove:
        for rdir in to_remove:
            try:
                shutil.rmtree(rdir)
            except OSError as exc:
                log.error(
                    'Unable to remove old hgfs remote cachedir %s: %s',
                    rdir, exc
                )
                failed.append(rdir)
            else:
                log.debug('hgfs removed old cachedir %s', rdir)
    for fdir in failed:
        to_remove.remove(fdir)
    return bool(to_remove), repos


def clear_cache():
    '''
    Completely clear hgfs cache
    '''
    fsb_cachedir = os.path.join(__opts__['cachedir'], 'hgfs')
    list_cachedir = os.path.join(__opts__['cachedir'], 'file_lists/hgfs')
    errors = []
    for rdir in (fsb_cachedir, list_cachedir):
        if os.path.exists(rdir):
            try:
                shutil.rmtree(rdir)
            except OSError as exc:
                errors.append('Unable to delete {0}: {1}'.format(rdir, exc))
    return errors


def clear_lock(remote=None):
    '''
    Clear update.lk

    ``remote`` can either be a dictionary containing repo configuration
    information, or a pattern. If the latter, then remotes for which the URL
    matches the pattern will be locked.
    '''
    def _do_clear_lock(repo):
        def _add_error(errlist, repo, exc):
            msg = ('Unable to remove update lock for {0} ({1}): {2} '
                   .format(repo['url'], repo['lockfile'], exc))
            log.debug(msg)
            errlist.append(msg)
        success = []
        failed = []
        if os.path.exists(repo['lockfile']):
            try:
                os.remove(repo['lockfile'])
            except OSError as exc:
                if exc.errno == errno.EISDIR:
                    # Somehow this path is a directory. Should never happen
                    # unless some wiseguy manually creates a directory at this
                    # path, but just in case, handle it.
                    try:
                        shutil.rmtree(repo['lockfile'])
                    except OSError as exc:
                        _add_error(failed, repo, exc)
                else:
                    _add_error(failed, repo, exc)
            else:
                msg = 'Removed lock for {0}'.format(repo['url'])
                log.debug(msg)
                success.append(msg)
        return success, failed

    if isinstance(remote, dict):
        return _do_clear_lock(remote)

    cleared = []
    errors = []
    for repo in init():
        if remote:
            try:
                if not fnmatch.fnmatch(repo['url'], remote):
                    continue
            except TypeError:
                # remote was non-string, try again
                if not fnmatch.fnmatch(repo['url'], six.text_type(remote)):
                    continue
        success, failed = _do_clear_lock(repo)
        cleared.extend(success)
        errors.extend(failed)
    return cleared, errors


def lock(remote=None):
    '''
    Place an update.lk

    ``remote`` can either be a dictionary containing repo configuration
    information, or a pattern. If the latter, then remotes for which the URL
    matches the pattern will be locked.
    '''
    def _do_lock(repo):
        success = []
        failed = []
        if not os.path.exists(repo['lockfile']):
            try:
                with salt.utils.files.fopen(repo['lockfile'], 'w'):
                    pass
            except (IOError, OSError) as exc:
                msg = ('Unable to set update lock for {0} ({1}): {2} '
                       .format(repo['url'], repo['lockfile'], exc))
                log.debug(msg)
                failed.append(msg)
            else:
                msg = 'Set lock for {0}'.format(repo['url'])
                log.debug(msg)
                success.append(msg)
        return success, failed

    if isinstance(remote, dict):
        return _do_lock(remote)

    locked = []
    errors = []
    for repo in init():
        if remote:
            try:
                if not fnmatch.fnmatch(repo['url'], remote):
                    continue
            except TypeError:
                # remote was non-string, try again
                if not fnmatch.fnmatch(repo['url'], six.text_type(remote)):
                    continue
        success, failed = _do_lock(repo)
        locked.extend(success)
        errors.extend(failed)

    return locked, errors


def update():
    '''
    Execute an hg pull on all of the repos
    '''
    # data for the fileserver event
    data = {'changed': False,
            'backend': 'hgfs'}
    # _clear_old_remotes runs init(), so use the value from there to avoid a
    # second init()
    data['changed'], repos = _clear_old_remotes()
    for repo in repos:
        if os.path.exists(repo['lockfile']):
            log.warning(
                'Update lockfile is present for hgfs remote %s, skipping. '
                'If this warning persists, it is possible that the update '
                'process was interrupted. Removing %s or running '
                '\'salt-run fileserver.clear_lock hgfs\' will allow updates '
                'to continue for this remote.', repo['url'], repo['lockfile']
            )
            continue
        _, errors = lock(repo)
        if errors:
            log.error(
                'Unable to set update lock for hgfs remote %s, skipping.',
                repo['url']
            )
            continue
        log.debug('hgfs is fetching from %s', repo['url'])
        repo['repo'].open()
        curtip = repo['repo'].tip()
        try:
            repo['repo'].pull()
        except Exception as exc:  # pylint: disable=broad-except
            log.error(
                'Exception %s caught while updating hgfs remote %s',
                exc, repo['url'], exc_info_on_loglevel=logging.DEBUG
            )
        else:
            newtip = repo['repo'].tip()
            if curtip[1] != newtip[1]:
                data['changed'] = True
        repo['repo'].close()
        clear_lock(repo)

    env_cache = os.path.join(__opts__['cachedir'], 'hgfs/envs.p')
    if data.get('changed', False) is True or not os.path.isfile(env_cache):
        env_cachedir = os.path.dirname(env_cache)
        if not os.path.exists(env_cachedir):
            os.makedirs(env_cachedir)
        new_envs = envs(ignore_cache=True)
        serial = salt.payload.Serial(__opts__)
        with salt.utils.files.fopen(env_cache, 'wb+') as fp_:
            fp_.write(serial.dumps(new_envs))
            log.trace('Wrote env cache data to %s', env_cache)

    # if there is a change, fire an event
    if __opts__.get('fileserver_events', False):
        with salt.utils.event.get_event(
                'master',
                __opts__['sock_dir'],
                __opts__['transport'],
                opts=__opts__,
                listen=False) as event:
            event.fire_event(data, tagify(['hgfs', 'update'], prefix='fileserver'))
    try:
        salt.fileserver.reap_fileserver_cache_dir(
            os.path.join(__opts__['cachedir'], 'hgfs/hash'),
            find_file
        )
    except (IOError, OSError):
        # Hash file won't exist if no files have yet been served up
        pass


def _env_is_exposed(env):
    '''
    Check if an environment is exposed by comparing it against a whitelist and
    blacklist.
    '''
    return salt.utils.stringutils.check_whitelist_blacklist(
        env,
        whitelist=__opts__['hgfs_saltenv_whitelist'],
        blacklist=__opts__['hgfs_saltenv_blacklist'],
    )


def envs(ignore_cache=False):
    '''
    Return a list of refs that can be used as environments
    '''
    if not ignore_cache:
        env_cache = os.path.join(__opts__['cachedir'], 'hgfs/envs.p')
        cache_match = salt.fileserver.check_env_cache(__opts__, env_cache)
        if cache_match is not None:
            return cache_match
    ret = set()
    for repo in init():
        repo['repo'].open()
        if repo['branch_method'] in ('branches', 'mixed'):
            for branch in _all_branches(repo['repo']):
                branch_name = branch[0]
                if branch_name == repo['base']:
                    branch_name = 'base'
                ret.add(branch_name)
        if repo['branch_method'] in ('bookmarks', 'mixed'):
            for bookmark in _all_bookmarks(repo['repo']):
                bookmark_name = bookmark[0]
                if bookmark_name == repo['base']:
                    bookmark_name = 'base'
                ret.add(bookmark_name)
        ret.update([x[0] for x in _all_tags(repo['repo'])])
        repo['repo'].close()
    return [x for x in sorted(ret) if _env_is_exposed(x)]


def find_file(path, tgt_env='base', **kwargs):  # pylint: disable=W0613
    '''
    Find the first file to match the path and ref, read the file out of hg
    and send the path to the newly cached file
    '''
    fnd = {'path': '',
           'rel': ''}
    if os.path.isabs(path) or tgt_env not in envs():
        return fnd

    dest = os.path.join(__opts__['cachedir'], 'hgfs/refs', tgt_env, path)
    hashes_glob = os.path.join(__opts__['cachedir'],
                               'hgfs/hash',
                               tgt_env,
                               '{0}.hash.*'.format(path))
    blobshadest = os.path.join(__opts__['cachedir'],
                               'hgfs/hash',
                               tgt_env,
                               '{0}.hash.blob_sha1'.format(path))
    lk_fn = os.path.join(__opts__['cachedir'],
                         'hgfs/hash',
                         tgt_env,
                         '{0}.lk'.format(path))
    destdir = os.path.dirname(dest)
    hashdir = os.path.dirname(blobshadest)
    if not os.path.isdir(destdir):
        try:
            os.makedirs(destdir)
        except OSError:
            # Path exists and is a file, remove it and retry
            os.remove(destdir)
            os.makedirs(destdir)
    if not os.path.isdir(hashdir):
        try:
            os.makedirs(hashdir)
        except OSError:
            # Path exists and is a file, remove it and retry
            os.remove(hashdir)
            os.makedirs(hashdir)

    for repo in init():
        if repo['mountpoint'] \
                and not path.startswith(repo['mountpoint'] + os.path.sep):
            continue
        repo_path = path[len(repo['mountpoint']):].lstrip(os.path.sep)
        if repo['root']:
            repo_path = os.path.join(repo['root'], repo_path)

        repo['repo'].open()
        ref = _get_ref(repo, tgt_env)
        if not ref:
            # Branch or tag not found in repo, try the next
            repo['repo'].close()
            continue
        salt.fileserver.wait_lock(lk_fn, dest)
        if os.path.isfile(blobshadest) and os.path.isfile(dest):
            with salt.utils.files.fopen(blobshadest, 'r') as fp_:
                sha = fp_.read()
                if sha == ref[2]:
                    fnd['rel'] = path
                    fnd['path'] = dest
                    repo['repo'].close()
                    return fnd
        try:
            repo['repo'].cat(
                ['path:{0}'.format(repo_path)], rev=ref[2], output=dest
            )
        except hglib.error.CommandError:
            repo['repo'].close()
            continue
        with salt.utils.files.fopen(lk_fn, 'w'):
            pass
        for filename in glob.glob(hashes_glob):
            try:
                os.remove(filename)
            except Exception:  # pylint: disable=broad-except
                pass
        with salt.utils.files.fopen(blobshadest, 'w+') as fp_:
            fp_.write(ref[2])
        try:
            os.remove(lk_fn)
        except (OSError, IOError):
            pass
        fnd['rel'] = path
        fnd['path'] = dest
        try:
            # Converting the stat result to a list, the elements of the
            # list correspond to the following stat_result params:
            # 0 => st_mode=33188
            # 1 => st_ino=10227377
            # 2 => st_dev=65026
            # 3 => st_nlink=1
            # 4 => st_uid=1000
            # 5 => st_gid=1000
            # 6 => st_size=1056233
            # 7 => st_atime=1468284229
            # 8 => st_mtime=1456338235
            # 9 => st_ctime=1456338235
            fnd['stat'] = list(os.stat(dest))
        except Exception:  # pylint: disable=broad-except
            pass
        repo['repo'].close()
        return fnd
    return fnd


def serve_file(load, fnd):
    '''
    Return a chunk from a file based on the data received
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    ret = {'data': '',
           'dest': ''}
    if not all(x in load for x in ('path', 'loc', 'saltenv')):
        return ret
    if not fnd['path']:
        return ret
    ret['dest'] = fnd['rel']
    gzip = load.get('gzip', None)
    fpath = os.path.normpath(fnd['path'])
    with salt.utils.files.fopen(fpath, 'rb') as fp_:
        fp_.seek(load['loc'])
        data = fp_.read(__opts__['file_buffer_size'])
        if data and six.PY3 and not salt.utils.files.is_binary(fpath):
            data = data.decode(__salt_system_encoding__)
        if gzip and data:
            data = salt.utils.gzip_util.compress(data, gzip)
            ret['gzip'] = gzip
        ret['data'] = data
    return ret


def file_hash(load, fnd):
    '''
    Return a file hash, the hash type is set in the master config file
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    if not all(x in load for x in ('path', 'saltenv')):
        return ''
    ret = {'hash_type': __opts__['hash_type']}
    relpath = fnd['rel']
    path = fnd['path']
    hashdest = os.path.join(__opts__['cachedir'],
                            'hgfs/hash',
                            load['saltenv'],
                            '{0}.hash.{1}'.format(relpath,
                                                  __opts__['hash_type']))
    if not os.path.isfile(hashdest):
        ret['hsum'] = salt.utils.hashutils.get_hash(path, __opts__['hash_type'])
        with salt.utils.files.fopen(hashdest, 'w+') as fp_:
            fp_.write(ret['hsum'])
        return ret
    else:
        with salt.utils.files.fopen(hashdest, 'rb') as fp_:
            ret['hsum'] = salt.utils.stringutils.to_unicode(fp_.read())
        return ret


def _file_lists(load, form):
    '''
    Return a dict containing the file lists for files and dirs
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    list_cachedir = os.path.join(__opts__['cachedir'], 'file_lists/hgfs')
    if not os.path.isdir(list_cachedir):
        try:
            os.makedirs(list_cachedir)
        except os.error:
            log.critical('Unable to make cachedir %s', list_cachedir)
            return []
    list_cache = os.path.join(list_cachedir, '{0}.p'.format(load['saltenv']))
    w_lock = os.path.join(list_cachedir, '.{0}.w'.format(load['saltenv']))
    cache_match, refresh_cache, save_cache = \
        salt.fileserver.check_file_list_cache(
            __opts__, form, list_cache, w_lock
        )
    if cache_match is not None:
        return cache_match
    if refresh_cache:
        ret = {}
        ret['files'] = _get_file_list(load)
        ret['dirs'] = _get_dir_list(load)
        if save_cache:
            salt.fileserver.write_file_list_cache(
                __opts__, ret, list_cache, w_lock
            )
        return ret.get(form, [])
    # Shouldn't get here, but if we do, this prevents a TypeError
    return []


def file_list(load):
    '''
    Return a list of all files on the file server in a specified environment
    '''
    return _file_lists(load, 'files')


def _get_file_list(load):
    '''
    Get a list of all files on the file server in a specified environment
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    if 'saltenv' not in load or load['saltenv'] not in envs():
        return []
    ret = set()
    for repo in init():
        repo['repo'].open()
        ref = _get_ref(repo, load['saltenv'])
        if ref:
            manifest = repo['repo'].manifest(rev=ref[1])
            for tup in manifest:
                relpath = os.path.relpath(tup[4], repo['root'])
                # Don't add files outside the hgfs_root
                if not relpath.startswith('../'):
                    ret.add(os.path.join(repo['mountpoint'], relpath))
        repo['repo'].close()
    return sorted(ret)


def file_list_emptydirs(load):  # pylint: disable=W0613
    '''
    Return a list of all empty directories on the master
    '''
    # Cannot have empty dirs in hg
    return []


def dir_list(load):
    '''
    Return a list of all directories on the master
    '''
    return _file_lists(load, 'dirs')


def _get_dir_list(load):
    '''
    Get a list of all directories on the master
    '''
    if 'env' in load:
        # "env" is not supported; Use "saltenv".
        load.pop('env')

    if 'saltenv' not in load or load['saltenv'] not in envs():
        return []
    ret = set()
    for repo in init():
        repo['repo'].open()
        ref = _get_ref(repo, load['saltenv'])
        if ref:
            manifest = repo['repo'].manifest(rev=ref[1])
            for tup in manifest:
                filepath = tup[4]
                split = filepath.rsplit('/', 1)
                while len(split) > 1:
                    relpath = os.path.relpath(split[0], repo['root'])
                    # Don't add '.'
                    if relpath != '.':
                        # Don't add files outside the hgfs_root
                        if not relpath.startswith('../'):
                            ret.add(os.path.join(repo['mountpoint'], relpath))
                    split = split[0].rsplit('/', 1)
        repo['repo'].close()
    if repo['mountpoint']:
        ret.add(repo['mountpoint'])
    return sorted(ret)
