# Source code for fontTools.ufoLib

    """
    A library for importing .ufo files and their descendants.
    Refer to http://unifiedfontobject.org for the UFO specification.

    The main interfaces are the :class:`.UFOReader` and :class:`.UFOWriter`
    classes, which support versions 1, 2, and 3 of the UFO specification.

    Set variables are available for external use that list the font
    info attribute names for the `fontinfo.plist` formats. These are:

    - :obj:`.fontInfoAttributesVersion1`
    - :obj:`.fontInfoAttributesVersion2`
    - :obj:`.fontInfoAttributesVersion3`

    A set listing the `fontinfo.plist` attributes that were deprecated
    in version 2 is available for external use:

    - :obj:`.deprecatedFontInfoAttributesVersion2`

    Functions that do basic validation on values for `fontinfo.plist`
    are available for external use. These are

    - :func:`.validateFontInfoVersion2ValueForAttribute`
    - :func:`.validateFontInfoVersion3ValueForAttribute`

    Value conversion functions are available for converting
    `fontinfo.plist` values between the possible format versions.

    - :func:`.convertFontInfoValueForAttributeFromVersion1ToVersion2`
    - :func:`.convertFontInfoValueForAttributeFromVersion2ToVersion1`
    - :func:`.convertFontInfoValueForAttributeFromVersion2ToVersion3`
    - :func:`.convertFontInfoValueForAttributeFromVersion3ToVersion2`
    """

    import os
    from copy import deepcopy
    from os import fsdecode
    import logging
    import zipfile
    import enum
    from collections import OrderedDict
    import fs
    import fs.base
    import fs.subfs
    import fs.errors
    import fs.copy
    import fs.osfs
    import fs.zipfs
    import fs.tempfs
    import fs.tools
    from fontTools.misc import plistlib
    from fontTools.ufoLib.validators import *
    from fontTools.ufoLib.filenames import userNameToFileName
    from fontTools.ufoLib.converters import convertUFO1OrUFO2KerningToUFO3Kerning
    from fontTools.ufoLib.errors import UFOLibError
    from fontTools.ufoLib.utils import numberTypes, _VersionTupleEnumMixin

    __all__ = [
        "makeUFOPath",
        "UFOLibError",
        "UFOReader",
        "UFOWriter",
        "UFOReaderWriter",
        "UFOFileStructure",
        "fontInfoAttributesVersion1",
        "fontInfoAttributesVersion2",
        "fontInfoAttributesVersion3",
        "deprecatedFontInfoAttributesVersion2",
        "validateFontInfoVersion2ValueForAttribute",
        "validateFontInfoVersion3ValueForAttribute",
        "convertFontInfoValueForAttributeFromVersion1ToVersion2",
        "convertFontInfoValueForAttributeFromVersion2ToVersion1",
    ]

    __version__ = "3.0.0"

    logger = logging.getLogger(__name__)

    # ---------
    # Constants
    # ---------

    DEFAULT_GLYPHS_DIRNAME = "glyphs"
    DATA_DIRNAME = "data"
    IMAGES_DIRNAME = "images"
    METAINFO_FILENAME = "metainfo.plist"
    FONTINFO_FILENAME = "fontinfo.plist"
    LIB_FILENAME = "lib.plist"
    GROUPS_FILENAME = "groups.plist"
    KERNING_FILENAME = "kerning.plist"
    FEATURES_FILENAME = "features.fea"
    LAYERCONTENTS_FILENAME = "layercontents.plist"
    LAYERINFO_FILENAME = "layerinfo.plist"

    DEFAULT_LAYER_NAME = "public.default"

    class UFOFormatVersion(tuple, _VersionTupleEnumMixin, enum.Enum):
        FORMAT_1_0 = (1, 0)
        FORMAT_2_0 = (2, 0)
        FORMAT_3_0 = (3, 0)

    # python 3.11 doesn't like when a mixin overrides a dunder method like __str__
    # for some reasons it keep using Enum.__str__, see
    # https://github.com/fonttools/fonttools/pull/2655
    UFOFormatVersion.__str__ = _VersionTupleEnumMixin.__str__

    class UFOFileStructure(enum.Enum):
        ZIP = "zip"
        PACKAGE = "package"

    # --------------
    # Shared Methods
    # --------------

    class _UFOBaseIO:
        def getFileModificationTime(self, path):
            """
            Returns the modification time for the file at the given path, as a
            floating point number giving the number of seconds since the epoch.
            The path must be relative to the UFO path.
            Returns None if the file does not exist.
            """
            try:
                dt = self.fs.getinfo(fsdecode(path), namespaces=["details"]).modified
            except (fs.errors.MissingInfoNamespace, fs.errors.ResourceNotFound):
                return None
            else:
                return dt.timestamp()

        def _getPlist(self, fileName, default=None):
            """
            Read a property list relative to the UFO filesystem's root.
            Raises UFOLibError if the file is missing and default is None,
            otherwise default is returned.

            The errors that could be raised during the reading of a plist are
            unpredictable and/or too large to list, so, a blind try: except:
            is done. If an exception occurs, a UFOLibError will be raised.
            """
            try:
                with self.fs.open(fileName, "rb") as f:
                    return plistlib.load(f)
            except fs.errors.ResourceNotFound:
                if default is None:
                    raise UFOLibError(
                        "'%s' is missing on %s. This file is required" % (fileName, self.fs)
                    )
                else:
                    return default
            except Exception as e:
                # TODO(anthrotype): try to narrow this down a little
                raise UFOLibError(f"'{fileName}' could not be read on {self.fs}: {e}")

        def _writePlist(self, fileName, obj):
            """
            Write a property list to a file relative to the UFO filesystem's root.

            Do this sort of atomically, making it harder to corrupt existing files,
            for example when plistlib encounters an error halfway during write.
            This also checks to see if text matches the text that is already in the
            file at path. If so, the file is not rewritten so that the modification
            date is preserved.

            The errors that could be raised during the writing of a plist are
            unpredictable and/or too large to list, so, a blind try: except: is done.
            If an exception occurs, a UFOLibError will be raised.
            """
            if self._havePreviousFile:
                try:
                    data = plistlib.dumps(obj)
                except Exception as e:
                    raise UFOLibError(
                        "'%s' could not be written on %s because "
                        "the data is not properly formatted: %s" % (fileName, self.fs, e)
                    )
                if self.fs.exists(fileName) and data == self.fs.readbytes(fileName):
                    return
                self.fs.writebytes(fileName, data)
            else:
                with self.fs.openbin(fileName, mode="w") as fp:
                    try:
                        plistlib.dump(obj, fp)
                    except Exception as e:
                        raise UFOLibError(
                            "'%s' could not be written on %s because "
                            "the data is not properly formatted: %s"
                            % (fileName, self.fs, e)
                        )

    # ----------
    # UFO Reader
    # ----------

    class UFOReader(_UFOBaseIO):
        """Read the various components of a .ufo.

        Attributes:
            path: An `os.PathLike` object pointing to the .ufo.
            validate: A boolean indicating if the data read should be
              validated. Defaults to `True`.

        By default read data is validated. Set ``validate`` to
        ``False`` to not validate the data.
        """

        def __init__(self, path, validate=True):
            if hasattr(path, "__fspath__"):  # support os.PathLike objects
                path = path.__fspath__()

            if isinstance(path, str):
                structure = _sniffFileStructure(path)
                try:
                    if structure is UFOFileStructure.ZIP:
                        parentFS = fs.zipfs.ZipFS(path, write=False, encoding="utf-8")
                    else:
                        parentFS = fs.osfs.OSFS(path)
                except fs.errors.CreateFailed as e:
                    raise UFOLibError(f"unable to open '{path}': {e}")

                if structure is UFOFileStructure.ZIP:
                    # .ufoz zip files must contain a single root directory, with arbitrary
                    # name, containing all the UFO files
                    rootDirs = [
                        p.name
                        for p in parentFS.scandir("/")
                        # exclude macOS metadata contained in zip file
                        if p.is_dir and p.name != "__MACOSX"
                    ]
                    if len(rootDirs) == 1:
                        # 'ClosingSubFS' ensures that the parent zip file is closed when
                        # its root subdirectory is closed
                        self.fs = parentFS.opendir(
                            rootDirs[0], factory=fs.subfs.ClosingSubFS
                        )
                    else:
                        raise UFOLibError(
                            "Expected exactly 1 root directory, found %d" % len(rootDirs)
                        )
                else:
                    # normal UFO 'packages' are just a single folder
                    self.fs = parentFS
                # when passed a path string, we make sure we close the newly opened fs
                # upon calling UFOReader.close method or context manager's __exit__
                self._shouldClose = True
                self._fileStructure = structure
            elif isinstance(path, fs.base.FS):
                filesystem = path
                try:
                    filesystem.check()
                except fs.errors.FilesystemClosed:
                    raise UFOLibError("the filesystem '%s' is closed" % path)
                else:
                    self.fs = filesystem
                try:
                    path = filesystem.getsyspath("/")
                except fs.errors.NoSysPath:
                    # network or in-memory FS may not map to the local one
                    path = str(filesystem)
                # when user passed an already initialized fs instance, it is her
                # responsibility to close it, thus UFOReader.close/__exit__ are no-op
                self._shouldClose = False
                # default to a 'package' structure
                self._fileStructure = UFOFileStructure.PACKAGE
            else:
                raise TypeError(
                    "Expected a path string or fs.base.FS object, found '%s'"
                    % type(path).__name__
                )
            self._path = fsdecode(path)
            self._validate = validate
            self._upConvertedKerningData = None

            try:
                self.readMetaInfo(validate=validate)
            except UFOLibError:
                self.close()
                raise

        # properties

        def _get_path(self):
            import warnings

            warnings.warn(
                "The 'path' attribute is deprecated; use the 'fs' attribute instead",
                DeprecationWarning,
                stacklevel=2,
            )
            return self._path

        path = property(_get_path, doc="The path of the UFO (DEPRECATED).")

        def _get_formatVersion(self):
            import warnings

            warnings.warn(
                "The 'formatVersion' attribute is deprecated; use the 'formatVersionTuple'",
                DeprecationWarning,
                stacklevel=2,
            )
            return self._formatVersion.major

        formatVersion = property(
            _get_formatVersion,
            doc="The (major) format version of the UFO. DEPRECATED: Use formatVersionTuple",
        )

        @property
        def formatVersionTuple(self):
            """The (major, minor) format version of the UFO.
            This is determined by reading metainfo.plist during __init__.
            """
            return self._formatVersion

        def _get_fileStructure(self):
            return self._fileStructure

        fileStructure = property(
            _get_fileStructure,
            doc=(
                "The file structure of the UFO: "
                "either UFOFileStructure.ZIP or UFOFileStructure.PACKAGE"
            ),
        )

        # up conversion

        def _upConvertKerning(self, validate):
            """
            Up convert kerning and groups in UFO 1 and 2.
            The data will be held internally until each bit of data
            has been retrieved. The conversion of both must be done
            at once, so the raw data is cached and an error is raised
            if one bit of data becomes obsolete before it is called.

            ``validate`` will validate the data.
            """
            if self._upConvertedKerningData:
                testKerning = self._readKerning()
                if testKerning != self._upConvertedKerningData["originalKerning"]:
                    raise UFOLibError(
                        "The data in kerning.plist has been modified since it was converted to UFO 3 format."
                    )
                testGroups = self._readGroups()
                if testGroups != self._upConvertedKerningData["originalGroups"]:
                    raise UFOLibError(
                        "The data in groups.plist has been modified since it was converted to UFO 3 format."
                    )
            else:
                groups = self._readGroups()
                if validate:
                    invalidFormatMessage = "groups.plist is not properly formatted."
                    if not isinstance(groups, dict):
                        raise UFOLibError(invalidFormatMessage)
                    for groupName, glyphList in groups.items():
                        if not isinstance(groupName, str):
                            raise UFOLibError(invalidFormatMessage)
                        elif not isinstance(glyphList, list):
                            raise UFOLibError(invalidFormatMessage)
                        for glyphName in glyphList:
                            if not isinstance(glyphName, str):
                                raise UFOLibError(invalidFormatMessage)
                self._upConvertedKerningData = dict(
                    kerning={},
                    originalKerning=self._readKerning(),
                    groups={},
                    originalGroups=groups,
                )
                # convert kerning and groups
                kerning, groups, conversionMaps = convertUFO1OrUFO2KerningToUFO3Kerning(
                    self._upConvertedKerningData["originalKerning"],
                    deepcopy(self._upConvertedKerningData["originalGroups"]),
                    self.getGlyphSet(),
                )
                # store
                self._upConvertedKerningData["kerning"] = kerning
                self._upConvertedKerningData["groups"] = groups
                self._upConvertedKerningData["groupRenameMaps"] = conversionMaps

        # support methods

        def readBytesFromPath(self, path):
            """
            Returns the bytes in the file at the given path.
            The path must be relative to the UFO's filesystem root.
            Returns None if the file does not exist.
            """
            try:
                return self.fs.readbytes(fsdecode(path))
            except fs.errors.ResourceNotFound:
                return None

        def getReadFileForPath(self, path, encoding=None):
            """
            Returns a file (or file-like) object for the file at the given path.
            The path must be relative to the UFO path.
            Returns None if the file does not exist.
            By default the file is opened in binary mode (reads bytes).
            If encoding is passed, the file is opened in text mode (reads str).

            Note: The caller is responsible for closing the open file.
            """
            path = fsdecode(path)
            try:
                if encoding is None:
                    return self.fs.openbin(path)
                else:
                    return self.fs.open(path, mode="r", encoding=encoding)
            except fs.errors.ResourceNotFound:
                return None

        # metainfo.plist

        def _readMetaInfo(self, validate=None):
            """
            Read metainfo.plist and return raw data. Only used for internal operations.

            ``validate`` will validate the read data, by default it is set
            to the class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            data = self._getPlist(METAINFO_FILENAME)
            if validate and not isinstance(data, dict):
                raise UFOLibError("metainfo.plist is not properly formatted.")
            try:
                formatVersionMajor = data["formatVersion"]
            except KeyError:
                raise UFOLibError(
                    f"Missing required formatVersion in '{METAINFO_FILENAME}' on {self.fs}"
                )
            formatVersionMinor = data.setdefault("formatVersionMinor", 0)

            try:
                formatVersion = UFOFormatVersion((formatVersionMajor, formatVersionMinor))
            except ValueError as e:
                unsupportedMsg = (
                    f"Unsupported UFO format ({formatVersionMajor}.{formatVersionMinor}) "
                    f"in '{METAINFO_FILENAME}' on {self.fs}"
                )
                if validate:
                    from fontTools.ufoLib.errors import UnsupportedUFOFormat

                    raise UnsupportedUFOFormat(unsupportedMsg) from e

                formatVersion = UFOFormatVersion.default()
                logger.warning(
                    "%s. Assuming the latest supported version (%s). "
                    "Some data may be skipped or parsed incorrectly",
                    unsupportedMsg,
                    formatVersion,
                )
            data["formatVersionTuple"] = formatVersion
            return data

        def readMetaInfo(self, validate=None):
            """
            Read metainfo.plist and set formatVersion. Only used for internal operations.

            ``validate`` will validate the read data, by default it is set
            to the class's validate value, can be overridden.
            """
            data = self._readMetaInfo(validate=validate)
            self._formatVersion = data["formatVersionTuple"]

        # groups.plist

        def _readGroups(self):
            groups = self._getPlist(GROUPS_FILENAME, {})
            # remove any duplicate glyphs in a kerning group
            for groupName, glyphList in groups.items():
                if groupName.startswith(("public.kern1.", "public.kern2.")):
                    groups[groupName] = list(OrderedDict.fromkeys(glyphList))
            return groups

        def readGroups(self, validate=None):
            """
            Read groups.plist. Returns a dict.
            ``validate`` will validate the read data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            # handle up conversion
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                self._upConvertKerning(validate)
                groups = self._upConvertedKerningData["groups"]
            # normal
            else:
                groups = self._readGroups()
            if validate:
                valid, message = groupsValidator(groups)
                if not valid:
                    raise UFOLibError(message)
            return groups

        def getKerningGroupConversionRenameMaps(self, validate=None):
            """
            Get maps defining the renaming that was done during any
            needed kerning group conversion. This method returns a
            dictionary of this form::

                    {
                            "side1" : {"old group name" : "new group name"},
                            "side2" : {"old group name" : "new group name"}
                    }

            When no conversion has been performed, the side1 and side2
            dictionaries will be empty.

            ``validate`` will validate the groups, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            if self._formatVersion >= UFOFormatVersion.FORMAT_3_0:
                return dict(side1={}, side2={})
            # use the public group reader to force the load and
            # conversion of the data if it hasn't happened yet.
            self.readGroups(validate=validate)
            return self._upConvertedKerningData["groupRenameMaps"]

        # fontinfo.plist

        def _readInfo(self, validate):
            data = self._getPlist(FONTINFO_FILENAME, {})
            if validate and not isinstance(data, dict):
                raise UFOLibError("fontinfo.plist is not properly formatted.")
            return data

        def readInfo(self, info, validate=None):
            """
            Read fontinfo.plist. It requires an object that allows
            setting attributes with names that follow the fontinfo.plist
            version 3 specification. This will write the attributes
            defined in the file into the object.

            ``validate`` will validate the read data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            infoDict = self._readInfo(validate)
            infoDataToSet = {}
            # version 1
            if self._formatVersion == UFOFormatVersion.FORMAT_1_0:
                for attr in fontInfoAttributesVersion1:
                    value = infoDict.get(attr)
                    if value is not None:
                        infoDataToSet[attr] = value
                infoDataToSet = _convertFontInfoDataVersion1ToVersion2(infoDataToSet)
                infoDataToSet = _convertFontInfoDataVersion2ToVersion3(infoDataToSet)
            # version 2
            elif self._formatVersion == UFOFormatVersion.FORMAT_2_0:
                for attr, dataValidationDict in list(
                    fontInfoAttributesVersion2ValueData.items()
                ):
                    value = infoDict.get(attr)
                    if value is None:
                        continue
                    infoDataToSet[attr] = value
                infoDataToSet = _convertFontInfoDataVersion2ToVersion3(infoDataToSet)
            # version 3.x
            elif self._formatVersion.major == UFOFormatVersion.FORMAT_3_0.major:
                for attr, dataValidationDict in list(
                    fontInfoAttributesVersion3ValueData.items()
                ):
                    value = infoDict.get(attr)
                    if value is None:
                        continue
                    infoDataToSet[attr] = value
            # unsupported version
            else:
                raise NotImplementedError(self._formatVersion)
            # validate data
            if validate:
                infoDataToSet = validateInfoVersion3Data(infoDataToSet)
            # populate the object
            for attr, value in list(infoDataToSet.items()):
                try:
                    setattr(info, attr, value)
                except AttributeError:
                    raise UFOLibError(
                        "The supplied info object does not support setting a necessary attribute (%s)."
                        % attr
                    )

        # kerning.plist

        def _readKerning(self):
            data = self._getPlist(KERNING_FILENAME, {})
            return data

        def readKerning(self, validate=None):
            """
            Read kerning.plist. Returns a dict.

            ``validate`` will validate the kerning data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            # handle up conversion
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                self._upConvertKerning(validate)
                kerningNested = self._upConvertedKerningData["kerning"]
            # normal
            else:
                kerningNested = self._readKerning()
            if validate:
                valid, message = kerningValidator(kerningNested)
                if not valid:
                    raise UFOLibError(message)
            # flatten
            kerning = {}
            for left in kerningNested:
                for right in kerningNested[left]:
                    value = kerningNested[left][right]
                    kerning[left, right] = value
            return kerning

        # lib.plist

        def readLib(self, validate=None):
            """
            Read lib.plist. Returns a dict.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            data = self._getPlist(LIB_FILENAME, {})
            if validate:
                valid, message = fontLibValidator(data)
                if not valid:
                    raise UFOLibError(message)
            return data

        # features.fea

        def readFeatures(self):
            """
            Read features.fea. Return a string.
            The returned string is empty if the file is missing.
            """
            try:
                with self.fs.open(FEATURES_FILENAME, "r", encoding="utf-8") as f:
                    return f.read()
            except fs.errors.ResourceNotFound:
                return ""

        # glyph sets & layers

        def _readLayerContents(self, validate):
            """
            Rebuild the layer contents list by checking what glyphsets
            are available on disk.

            ``validate`` will validate the layer contents.
            """
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                return [(DEFAULT_LAYER_NAME, DEFAULT_GLYPHS_DIRNAME)]
            contents = self._getPlist(LAYERCONTENTS_FILENAME)
            if validate:
                valid, error = layerContentsValidator(contents, self.fs)
                if not valid:
                    raise UFOLibError(error)
            return contents

        def getLayerNames(self, validate=None):
            """
            Get the ordered layer names from layercontents.plist.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            layerContents = self._readLayerContents(validate)
            layerNames = [layerName for layerName, directoryName in layerContents]
            return layerNames

        def getDefaultLayerName(self, validate=None):
            """
            Get the default layer name from layercontents.plist.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            layerContents = self._readLayerContents(validate)
            for layerName, layerDirectory in layerContents:
                if layerDirectory == DEFAULT_GLYPHS_DIRNAME:
                    return layerName
            # this will already have been raised during __init__
            raise UFOLibError("The default layer is not defined in layercontents.plist.")

        def getGlyphSet(self, layerName=None, validateRead=None, validateWrite=None):
            """
            Return the GlyphSet associated with the
            glyphs directory mapped to layerName
            in the UFO. If layerName is not provided,
            the name retrieved with getDefaultLayerName
            will be used.

            ``validateRead`` will validate the read data, by default it is set to the
            class's validate value, can be overridden.
            ``validateWrite`` will validate the written data, by default it is set to the
            class's validate value, can be overridden.
            """
            from fontTools.ufoLib.glifLib import GlyphSet

            if validateRead is None:
                validateRead = self._validate
            if validateWrite is None:
                validateWrite = self._validate
            if layerName is None:
                layerName = self.getDefaultLayerName(validate=validateRead)
            directory = None
            layerContents = self._readLayerContents(validateRead)
            for storedLayerName, storedLayerDirectory in layerContents:
                if layerName == storedLayerName:
                    directory = storedLayerDirectory
                    break
            if directory is None:
                raise UFOLibError('No glyphs directory is mapped to "%s".' % layerName)
            try:
                glyphSubFS = self.fs.opendir(directory)
            except fs.errors.ResourceNotFound:
                raise UFOLibError(f"No '{directory}' directory for layer '{layerName}'")
            return GlyphSet(
                glyphSubFS,
                ufoFormatVersion=self._formatVersion,
                validateRead=validateRead,
                validateWrite=validateWrite,
                expectContentsFile=True,
            )

        def getCharacterMapping(self, layerName=None, validate=None):
            """
            Return a dictionary that maps unicode values (ints) to
            lists of glyph names.
            """
            if validate is None:
                validate = self._validate
            glyphSet = self.getGlyphSet(
                layerName, validateRead=validate, validateWrite=True
            )
            allUnicodes = glyphSet.getUnicodes()
            cmap = {}
            for glyphName, unicodes in allUnicodes.items():
                for code in unicodes:
                    if code in cmap:
                        cmap[code].append(glyphName)
                    else:
                        cmap[code] = [glyphName]
            return cmap

        # /data

        def getDataDirectoryListing(self):
            """
            Returns a list of all files in the data directory.
            The returned paths will be relative to the UFO.
            This will not list directory names, only file names.
            Thus, empty directories will be skipped.
            """
            try:
                self._dataFS = self.fs.opendir(DATA_DIRNAME)
            except fs.errors.ResourceNotFound:
                return []
            except fs.errors.DirectoryExpected:
                raise UFOLibError('The UFO contains a "data" file instead of a directory.')
            try:
                # fs Walker.files method returns "absolute" paths (in terms of the
                # root of the 'data' SubFS), so we strip the leading '/' to make
                # them relative
                return [p.lstrip("/") for p in self._dataFS.walk.files()]
            except fs.errors.ResourceError:
                return []

        def getImageDirectoryListing(self, validate=None):
            """
            Returns a list of all image file names in
            the images directory. Each of the images will
            have been verified to have the PNG signature.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                return []
            if validate is None:
                validate = self._validate
            try:
                self._imagesFS = imagesFS = self.fs.opendir(IMAGES_DIRNAME)
            except fs.errors.ResourceNotFound:
                return []
            except fs.errors.DirectoryExpected:
                raise UFOLibError(
                    'The UFO contains an "images" file instead of a directory.'
                )
            result = []
            for path in imagesFS.scandir("/"):
                if path.is_dir:
                    # silently skip this as version control
                    # systems often have hidden directories
                    continue
                if validate:
                    with imagesFS.openbin(path.name) as fp:
                        valid, error = pngValidator(fileObj=fp)
                    if valid:
                        result.append(path.name)
                else:
                    result.append(path.name)
            return result

        def readData(self, fileName):
            """
            Return bytes for the file named 'fileName' inside the 'data/' directory.
            """
            fileName = fsdecode(fileName)
            try:
                try:
                    dataFS = self._dataFS
                except AttributeError:
                    # in case readData is called before getDataDirectoryListing
                    dataFS = self.fs.opendir(DATA_DIRNAME)
                data = dataFS.readbytes(fileName)
            except fs.errors.ResourceNotFound:
                raise UFOLibError(f"No data file named '{fileName}' on {self.fs}")
            return data

        def readImage(self, fileName, validate=None):
            """
            Return image data for the file named fileName.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                raise UFOLibError(
                    f"Reading images is not allowed in UFO {self._formatVersion.major}."
                )
            fileName = fsdecode(fileName)
            try:
                try:
                    imagesFS = self._imagesFS
                except AttributeError:
                    # in case readImage is called before getImageDirectoryListing
                    imagesFS = self.fs.opendir(IMAGES_DIRNAME)
                data = imagesFS.readbytes(fileName)
            except fs.errors.ResourceNotFound:
                raise UFOLibError(f"No image file named '{fileName}' on {self.fs}")
            if validate:
                valid, error = pngValidator(data=data)
                if not valid:
                    raise UFOLibError(error)
            return data

        def close(self):
            if self._shouldClose:
                self.fs.close()

        def __enter__(self):
            return self

        def __exit__(self, exc_type, exc_value, exc_tb):
            self.close()

    # ----------
    # UFO Writer
    # ----------

    class UFOWriter(UFOReader):
        """Write the various components of a .ufo.

        Attributes:
            path: An `os.PathLike` object pointing to the .ufo.
            formatVersion: the UFO format version as a tuple of integers (major, minor),
                or as a single integer for the major digit only (minor is implied to be 0).
                By default, the latest formatVersion will be used; currently it is 3.0,
                which is equivalent to formatVersion=(3, 0).
            fileCreator: The creator of the .ufo file. Defaults to
                `com.github.fonttools.ufoLib`.
            structure: The internal structure of the .ufo file: either `ZIP` or `PACKAGE`.
            validate: A boolean indicating if the data read should be validated. Defaults
                to `True`.

        By default, the written data will be validated before writing. Set ``validate`` to
        ``False`` if you do not want to validate the data. Validation can also be overriden
        on a per-method level if desired.

        Raises:
            UnsupportedUFOFormat: An exception indicating that the requested UFO
                formatVersion is not supported.
        """

        def __init__(
            self,
            path,
            formatVersion=None,
            fileCreator="com.github.fonttools.ufoLib",
            structure=None,
            validate=True,
        ):
            try:
                formatVersion = UFOFormatVersion(formatVersion)
            except ValueError as e:
                from fontTools.ufoLib.errors import UnsupportedUFOFormat

                raise UnsupportedUFOFormat(
                    f"Unsupported UFO format: {formatVersion!r}"
                ) from e

            if hasattr(path, "__fspath__"):  # support os.PathLike objects
                path = path.__fspath__()

            if isinstance(path, str):
                # normalize path by removing trailing or double slashes
                path = os.path.normpath(path)
                havePreviousFile = os.path.exists(path)
                if havePreviousFile:
                    # ensure we use the same structure as the destination
                    existingStructure = _sniffFileStructure(path)
                    if structure is not None:
                        try:
                            structure = UFOFileStructure(structure)
                        except ValueError:
                            raise UFOLibError(
                                "Invalid or unsupported structure: '%s'" % structure
                            )
                        if structure is not existingStructure:
                            raise UFOLibError(
                                "A UFO with a different structure (%s) already exists "
                                "at the given path: '%s'" % (existingStructure, path)
                            )
                    else:
                        structure = existingStructure
                else:
                    # if not exists, default to 'package' structure
                    if structure is None:
                        structure = UFOFileStructure.PACKAGE
                    dirName = os.path.dirname(path)
                    if dirName and not os.path.isdir(dirName):
                        raise UFOLibError(
                            "Cannot write to '%s': directory does not exist" % path
                        )
                if structure is UFOFileStructure.ZIP:
                    if havePreviousFile:
                        # we can't write a zip in-place, so we have to copy its
                        # contents to a temporary location and work from there, then
                        # upon closing UFOWriter we create the final zip file
                        parentFS = fs.tempfs.TempFS()
                        with fs.zipfs.ZipFS(path, encoding="utf-8") as origFS:
                            fs.copy.copy_fs(origFS, parentFS)
                        # if output path is an existing zip, we require that it contains
                        # one, and only one, root directory (with arbitrary name), in turn
                        # containing all the existing UFO contents
                        rootDirs = [
                            p.name
                            for p in parentFS.scandir("/")
                            # exclude macOS metadata contained in zip file
                            if p.is_dir and p.name != "__MACOSX"
                        ]
                        if len(rootDirs) != 1:
                            raise UFOLibError(
                                "Expected exactly 1 root directory, found %d"
                                % len(rootDirs)
                            )
                        else:
                            # 'ClosingSubFS' ensures that the parent filesystem is closed
                            # when its root subdirectory is closed
                            self.fs = parentFS.opendir(
                                rootDirs[0], factory=fs.subfs.ClosingSubFS
                            )
                    else:
                        # if the output zip file didn't exist, we create the root folder;
                        # we name it the same as input 'path', but with '.ufo' extension
                        rootDir = os.path.splitext(os.path.basename(path))[0] + ".ufo"
                        parentFS = fs.zipfs.ZipFS(path, write=True, encoding="utf-8")
                        parentFS.makedir(rootDir)
                        self.fs = parentFS.opendir(rootDir, factory=fs.subfs.ClosingSubFS)
                else:
                    self.fs = fs.osfs.OSFS(path, create=True)
                self._fileStructure = structure
                self._havePreviousFile = havePreviousFile
                self._shouldClose = True
            elif isinstance(path, fs.base.FS):
                filesystem = path
                try:
                    filesystem.check()
                except fs.errors.FilesystemClosed:
                    raise UFOLibError("the filesystem '%s' is closed" % path)
                else:
                    self.fs = filesystem
                try:
                    path = filesystem.getsyspath("/")
                except fs.errors.NoSysPath:
                    # network or in-memory FS may not map to the local one
                    path = str(filesystem)
                # if passed an FS object, always use 'package' structure
                if structure and structure is not UFOFileStructure.PACKAGE:
                    import warnings

                    warnings.warn(
                        "The 'structure' argument is not used when input is an FS object",
                        UserWarning,
                        stacklevel=2,
                    )
                self._fileStructure = UFOFileStructure.PACKAGE
                # if FS contains a "metainfo.plist", we consider it non-empty
                self._havePreviousFile = filesystem.exists(METAINFO_FILENAME)
                # the user is responsible for closing the FS object
                self._shouldClose = False
            else:
                raise TypeError(
                    "Expected a path string or fs object, found %s" % type(path).__name__
                )

            # establish some basic stuff
            self._path = fsdecode(path)
            self._formatVersion = formatVersion
            self._fileCreator = fileCreator
            self._downConversionKerningData = None
            self._validate = validate
            # if the file already exists, get the format version.
            # this will be needed for up and down conversion.
            previousFormatVersion = None
            if self._havePreviousFile:
                metaInfo = self._readMetaInfo(validate=validate)
                previousFormatVersion = metaInfo["formatVersionTuple"]
                # catch down conversion
                if previousFormatVersion > formatVersion:
                    from fontTools.ufoLib.errors import UnsupportedUFOFormat

                    raise UnsupportedUFOFormat(
                        "The UFO located at this path is a higher version "
                        f"({previousFormatVersion}) than the version ({formatVersion}) "
                        "that is trying to be written. This is not supported."
                    )
            # handle the layer contents
            self.layerContents = {}
            if previousFormatVersion is not None and previousFormatVersion.major >= 3:
                # already exists
                self.layerContents = OrderedDict(self._readLayerContents(validate))
            else:
                # previous < 3
                # imply the layer contents
                if self.fs.exists(DEFAULT_GLYPHS_DIRNAME):
                    self.layerContents = {DEFAULT_LAYER_NAME: DEFAULT_GLYPHS_DIRNAME}
            # write the new metainfo
            self._writeMetaInfo()

        # properties

        def _get_fileCreator(self):
            return self._fileCreator

        fileCreator = property(
            _get_fileCreator,
            doc="The file creator of the UFO. This is set into metainfo.plist during __init__.",
        )

        # support methods for file system interaction

        def copyFromReader(self, reader, sourcePath, destPath):
            """
            Copy the sourcePath in the provided UFOReader to destPath
            in this writer. The paths must be relative. This works with
            both individual files and directories.
            """
            if not isinstance(reader, UFOReader):
                raise UFOLibError("The reader must be an instance of UFOReader.")
            sourcePath = fsdecode(sourcePath)
            destPath = fsdecode(destPath)
            if not reader.fs.exists(sourcePath):
                raise UFOLibError(
                    'The reader does not have data located at "%s".' % sourcePath
                )
            if self.fs.exists(destPath):
                raise UFOLibError('A file named "%s" already exists.' % destPath)
            # create the destination directory if it doesn't exist
            self.fs.makedirs(fs.path.dirname(destPath), recreate=True)
            if reader.fs.isdir(sourcePath):
                fs.copy.copy_dir(reader.fs, sourcePath, self.fs, destPath)
            else:
                fs.copy.copy_file(reader.fs, sourcePath, self.fs, destPath)

        def writeBytesToPath(self, path, data):
            """
            Write bytes to a path relative to the UFO filesystem's root.
            If writing to an existing UFO, check to see if data matches the data
            that is already in the file at path; if so, the file is not rewritten
            so that the modification date is preserved.
            If needed, the directory tree for the given path will be built.
            """
            path = fsdecode(path)
            if self._havePreviousFile:
                if self.fs.isfile(path) and data == self.fs.readbytes(path):
                    return
            try:
                self.fs.writebytes(path, data)
            except fs.errors.FileExpected:
                raise UFOLibError("A directory exists at '%s'" % path)
            except fs.errors.ResourceNotFound:
                self.fs.makedirs(fs.path.dirname(path), recreate=True)
                self.fs.writebytes(path, data)

        def getFileObjectForPath(self, path, mode="w", encoding=None):
            """
            Returns a file (or file-like) object for the
            file at the given path. The path must be relative
            to the UFO path. Returns None if the file does
            not exist and the mode is "r" or "rb.
            An encoding may be passed if the file is opened in text mode.

            Note: The caller is responsible for closing the open file.
            """
            path = fsdecode(path)
            try:
                return self.fs.open(path, mode=mode, encoding=encoding)
            except fs.errors.ResourceNotFound as e:
                m = mode[0]
                if m == "r":
                    # XXX I think we should just let it raise. The docstring,
                    # however, says that this returns None if mode is 'r'
                    return None
                elif m == "w" or m == "a" or m == "x":
                    self.fs.makedirs(fs.path.dirname(path), recreate=True)
                    return self.fs.open(path, mode=mode, encoding=encoding)
            except fs.errors.ResourceError as e:
                return UFOLibError(f"unable to open '{path}' on {self.fs}: {e}")

        def removePath(self, path, force=False, removeEmptyParents=True):
            """
            Remove the file (or directory) at path. The path
            must be relative to the UFO.
            Raises UFOLibError if the path doesn't exist.
            If force=True, ignore non-existent paths.
            If the directory where 'path' is located becomes empty, it will
            be automatically removed, unless 'removeEmptyParents' is False.
            """
            path = fsdecode(path)
            try:
                self.fs.remove(path)
            except fs.errors.FileExpected:
                self.fs.removetree(path)
            except fs.errors.ResourceNotFound:
                if not force:
                    raise UFOLibError(f"'{path}' does not exist on {self.fs}")
            if removeEmptyParents:
                parent = fs.path.dirname(path)
                if parent:
                    fs.tools.remove_empty(self.fs, parent)

        # alias kept for backward compatibility with old API
        removeFileForPath = removePath

        # UFO mod time

        def setModificationTime(self):
            """
            Set the UFO modification time to the current time.
            This is never called automatically. It is up to the
            caller to call this when finished working on the UFO.
            """
            path = self._path
            if path is not None and os.path.exists(path):
                try:
                    # this may fail on some filesystems (e.g. SMB servers)
                    os.utime(path, None)
                except OSError as e:
                    logger.warning("Failed to set modified time: %s", e)

        # metainfo.plist

        def _writeMetaInfo(self):
            metaInfo = dict(
                creator=self._fileCreator,
                formatVersion=self._formatVersion.major,
            )
            if self._formatVersion.minor != 0:
                metaInfo["formatVersionMinor"] = self._formatVersion.minor
            self._writePlist(METAINFO_FILENAME, metaInfo)

        # groups.plist

        def setKerningGroupConversionRenameMaps(self, maps):
            """
            Set maps defining the renaming that should be done
            when writing groups and kerning in UFO 1 and UFO 2.
            This will effectively undo the conversion done when
            UFOReader reads this data. The dictionary should have
            this form::

                    {
                            "side1" : {"group name to use when writing" : "group name in data"},
                            "side2" : {"group name to use when writing" : "group name in data"}
                    }

            This is the same form returned by UFOReader's
            getKerningGroupConversionRenameMaps method.
            """
            if self._formatVersion >= UFOFormatVersion.FORMAT_3_0:
                return  # XXX raise an error here
            # flip the dictionaries
            remap = {}
            for side in ("side1", "side2"):
                for writeName, dataName in list(maps[side].items()):
                    remap[dataName] = writeName
            self._downConversionKerningData = dict(groupRenameMap=remap)

        def writeGroups(self, groups, validate=None):
            """
            Write groups.plist. This method requires a
            dict of glyph groups as an argument.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            # validate the data structure
            if validate:
                valid, message = groupsValidator(groups)
                if not valid:
                    raise UFOLibError(message)
            # down convert
            if (
                self._formatVersion < UFOFormatVersion.FORMAT_3_0
                and self._downConversionKerningData is not None
            ):
                remap = self._downConversionKerningData["groupRenameMap"]
                remappedGroups = {}
                # there are some edge cases here that are ignored:
                # 1. if a group is being renamed to a name that
                #    already exists, the existing group is always
                #    overwritten. (this is why there are two loops
                #    below.) there doesn't seem to be a logical
                #    solution to groups mismatching and overwriting
                #    with the specifiecd group seems like a better
                #    solution than throwing an error.
                # 2. if side 1 and side 2 groups are being renamed
                #    to the same group name there is no check to
                #    ensure that the contents are identical. that
                #    is left up to the caller.
                for name, contents in list(groups.items()):
                    if name in remap:
                        continue
                    remappedGroups[name] = contents
                for name, contents in list(groups.items()):
                    if name not in remap:
                        continue
                    name = remap[name]
                    remappedGroups[name] = contents
                groups = remappedGroups
            # pack and write
            groupsNew = {}
            for key, value in groups.items():
                groupsNew[key] = list(value)
            if groupsNew:
                self._writePlist(GROUPS_FILENAME, groupsNew)
            elif self._havePreviousFile:
                self.removePath(GROUPS_FILENAME, force=True, removeEmptyParents=False)

        # fontinfo.plist

        def writeInfo(self, info, validate=None):
            """
            Write info.plist. This method requires an object
            that supports getting attributes that follow the
            fontinfo.plist version 2 specification. Attributes
            will be taken from the given object and written
            into the file.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            # gather version 3 data
            infoData = {}
            for attr in list(fontInfoAttributesVersion3ValueData.keys()):
                if hasattr(info, attr):
                    try:
                        value = getattr(info, attr)
                    except AttributeError:
                        raise UFOLibError(
                            "The supplied info object does not support getting a necessary attribute (%s)."
                            % attr
                        )
                    if value is None:
                        continue
                    infoData[attr] = value
            # down convert data if necessary and validate
            if self._formatVersion == UFOFormatVersion.FORMAT_3_0:
                if validate:
                    infoData = validateInfoVersion3Data(infoData)
            elif self._formatVersion == UFOFormatVersion.FORMAT_2_0:
                infoData = _convertFontInfoDataVersion3ToVersion2(infoData)
                if validate:
                    infoData = validateInfoVersion2Data(infoData)
            elif self._formatVersion == UFOFormatVersion.FORMAT_1_0:
                infoData = _convertFontInfoDataVersion3ToVersion2(infoData)
                if validate:
                    infoData = validateInfoVersion2Data(infoData)
                infoData = _convertFontInfoDataVersion2ToVersion1(infoData)
            # write file if there is anything to write
            if infoData:
                self._writePlist(FONTINFO_FILENAME, infoData)

        # kerning.plist

        def writeKerning(self, kerning, validate=None):
            """
            Write kerning.plist. This method requires a
            dict of kerning pairs as an argument.

            This performs basic structural validation of the kerning,
            but it does not check for compliance with the spec in
            regards to conflicting pairs. The assumption is that the
            kerning data being passed is standards compliant.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            # validate the data structure
            if validate:
                invalidFormatMessage = "The kerning is not properly formatted."
                if not isDictEnough(kerning):
                    raise UFOLibError(invalidFormatMessage)
                for pair, value in list(kerning.items()):
                    if not isinstance(pair, (list, tuple)):
                        raise UFOLibError(invalidFormatMessage)
                    if not len(pair) == 2:
                        raise UFOLibError(invalidFormatMessage)
                    if not isinstance(pair[0], str):
                        raise UFOLibError(invalidFormatMessage)
                    if not isinstance(pair[1], str):
                        raise UFOLibError(invalidFormatMessage)
                    if not isinstance(value, numberTypes):
                        raise UFOLibError(invalidFormatMessage)
            # down convert
            if (
                self._formatVersion < UFOFormatVersion.FORMAT_3_0
                and self._downConversionKerningData is not None
            ):
                remap = self._downConversionKerningData["groupRenameMap"]
                remappedKerning = {}
                for (side1, side2), value in list(kerning.items()):
                    side1 = remap.get(side1, side1)
                    side2 = remap.get(side2, side2)
                    remappedKerning[side1, side2] = value
                kerning = remappedKerning
            # pack and write
            kerningDict = {}
            for left, right in kerning.keys():
                value = kerning[left, right]
                if left not in kerningDict:
                    kerningDict[left] = {}
                kerningDict[left][right] = value
            if kerningDict:
                self._writePlist(KERNING_FILENAME, kerningDict)
            elif self._havePreviousFile:
                self.removePath(KERNING_FILENAME, force=True, removeEmptyParents=False)

        # lib.plist

        def writeLib(self, libDict, validate=None):
            """
            Write lib.plist. This method requires a
            lib dict as an argument.

            ``validate`` will validate the data, by default it is set to the
            class's validate value, can be overridden.
            """
            if validate is None:
                validate = self._validate
            if validate:
                valid, message = fontLibValidator(libDict)
                if not valid:
                    raise UFOLibError(message)
            if libDict:
                self._writePlist(LIB_FILENAME, libDict)
            elif self._havePreviousFile:
                self.removePath(LIB_FILENAME, force=True, removeEmptyParents=False)

        # features.fea

        def writeFeatures(self, features, validate=None):
            """
            Write features.fea. This method requires a
            features string as an argument.
            """
            if validate is None:
                validate = self._validate
            if self._formatVersion == UFOFormatVersion.FORMAT_1_0:
                raise UFOLibError("features.fea is not allowed in UFO Format Version 1.")
            if validate:
                if not isinstance(features, str):
                    raise UFOLibError("The features are not text.")
            if features:
                self.writeBytesToPath(FEATURES_FILENAME, features.encode("utf8"))
            elif self._havePreviousFile:
                self.removePath(FEATURES_FILENAME, force=True, removeEmptyParents=False)

        # glyph sets & layers

        def writeLayerContents(self, layerOrder=None, validate=None):
            """
            Write the layercontents.plist file. This method  *must* be called
            after all glyph sets have been written.
            """
            if validate is None:
                validate = self._validate
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                return
            if layerOrder is not None:
                newOrder = []
                for layerName in layerOrder:
                    if layerName is None:
                        layerName = DEFAULT_LAYER_NAME
                    newOrder.append(layerName)
                layerOrder = newOrder
            else:
                layerOrder = list(self.layerContents.keys())
            if validate and set(layerOrder) != set(self.layerContents.keys()):
                raise UFOLibError(
                    "The layer order content does not match the glyph sets that have been created."
                )
            layerContents = [
                (layerName, self.layerContents[layerName]) for layerName in layerOrder
            ]
            self._writePlist(LAYERCONTENTS_FILENAME, layerContents)

        def _findDirectoryForLayerName(self, layerName):
            foundDirectory = None
            for existingLayerName, directoryName in list(self.layerContents.items()):
                if layerName is None and directoryName == DEFAULT_GLYPHS_DIRNAME:
                    foundDirectory = directoryName
                    break
                elif existingLayerName == layerName:
                    foundDirectory = directoryName
                    break
            if not foundDirectory:
                raise UFOLibError(
                    "Could not locate a glyph set directory for the layer named %s."
                    % layerName
                )
            return foundDirectory

        def getGlyphSet(
            self,
            layerName=None,
            defaultLayer=True,
            glyphNameToFileNameFunc=None,
            validateRead=None,
            validateWrite=None,
            expectContentsFile=False,
        ):
            """
            Return the GlyphSet object associated with the
            appropriate glyph directory in the .ufo.
            If layerName is None, the default glyph set
            will be used. The defaultLayer flag indictes
            that the layer should be saved into the default
            glyphs directory.

            ``validateRead`` will validate the read data, by default it is set to the
            class's validate value, can be overridden.
            ``validateWrte`` will validate the written data, by default it is set to the
            class's validate value, can be overridden.
            ``expectContentsFile`` will raise a GlifLibError if a contents.plist file is
            not found on the glyph set file system. This should be set to ``True`` if you
            are reading an existing UFO and ``False`` if you use ``getGlyphSet`` to create
            a fresh	glyph set.
            """
            if validateRead is None:
                validateRead = self._validate
            if validateWrite is None:
                validateWrite = self._validate
            # only default can be written in < 3
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0 and (
                not defaultLayer or layerName is not None
            ):
                raise UFOLibError(
                    f"Only the default layer can be writen in UFO {self._formatVersion.major}."
                )
            # locate a layer name when None has been given
            if layerName is None and defaultLayer:
                for existingLayerName, directory in self.layerContents.items():
                    if directory == DEFAULT_GLYPHS_DIRNAME:
                        layerName = existingLayerName
                if layerName is None:
                    layerName = DEFAULT_LAYER_NAME
            elif layerName is None and not defaultLayer:
                raise UFOLibError("A layer name must be provided for non-default layers.")
            # move along to format specific writing
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                return self._getDefaultGlyphSet(
                    validateRead,
                    validateWrite,
                    glyphNameToFileNameFunc=glyphNameToFileNameFunc,
                    expectContentsFile=expectContentsFile,
                )
            elif self._formatVersion.major == UFOFormatVersion.FORMAT_3_0.major:
                return self._getGlyphSetFormatVersion3(
                    validateRead,
                    validateWrite,
                    layerName=layerName,
                    defaultLayer=defaultLayer,
                    glyphNameToFileNameFunc=glyphNameToFileNameFunc,
                    expectContentsFile=expectContentsFile,
                )
            else:
                raise NotImplementedError(self._formatVersion)

        def _getDefaultGlyphSet(
            self,
            validateRead,
            validateWrite,
            glyphNameToFileNameFunc=None,
            expectContentsFile=False,
        ):
            from fontTools.ufoLib.glifLib import GlyphSet

            glyphSubFS = self.fs.makedir(DEFAULT_GLYPHS_DIRNAME, recreate=True)
            return GlyphSet(
                glyphSubFS,
                glyphNameToFileNameFunc=glyphNameToFileNameFunc,
                ufoFormatVersion=self._formatVersion,
                validateRead=validateRead,
                validateWrite=validateWrite,
                expectContentsFile=expectContentsFile,
            )

        def _getGlyphSetFormatVersion3(
            self,
            validateRead,
            validateWrite,
            layerName=None,
            defaultLayer=True,
            glyphNameToFileNameFunc=None,
            expectContentsFile=False,
        ):
            from fontTools.ufoLib.glifLib import GlyphSet

            # if the default flag is on, make sure that the default in the file
            # matches the default being written. also make sure that this layer
            # name is not already linked to a non-default layer.
            if defaultLayer:
                for existingLayerName, directory in self.layerContents.items():
                    if directory == DEFAULT_GLYPHS_DIRNAME:
                        if existingLayerName != layerName:
                            raise UFOLibError(
                                "Another layer ('%s') is already mapped to the default directory."
                                % existingLayerName
                            )
                    elif existingLayerName == layerName:
                        raise UFOLibError(
                            "The layer name is already mapped to a non-default layer."
                        )
            # get an existing directory name
            if layerName in self.layerContents:
                directory = self.layerContents[layerName]
            # get a  new directory name
            else:
                if defaultLayer:
                    directory = DEFAULT_GLYPHS_DIRNAME
                else:
                    # not caching this could be slightly expensive,
                    # but caching it will be cumbersome
                    existing = {d.lower() for d in self.layerContents.values()}
                    directory = userNameToFileName(
                        layerName, existing=existing, prefix="glyphs."
                    )
            # make the directory
            glyphSubFS = self.fs.makedir(directory, recreate=True)
            # store the mapping
            self.layerContents[layerName] = directory
            # load the glyph set
            return GlyphSet(
                glyphSubFS,
                glyphNameToFileNameFunc=glyphNameToFileNameFunc,
                ufoFormatVersion=self._formatVersion,
                validateRead=validateRead,
                validateWrite=validateWrite,
                expectContentsFile=expectContentsFile,
            )

        def renameGlyphSet(self, layerName, newLayerName, defaultLayer=False):
            """
            Rename a glyph set.

            Note: if a GlyphSet object has already been retrieved for
            layerName, it is up to the caller to inform that object that
            the directory it represents has changed.
            """
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                # ignore renaming glyph sets for UFO1 UFO2
                # just write the data from the default layer
                return
            # the new and old names can be the same
            # as long as the default is being switched
            if layerName == newLayerName:
                # if the default is off and the layer is already not the default, skip
                if (
                    self.layerContents[layerName] != DEFAULT_GLYPHS_DIRNAME
                    and not defaultLayer
                ):
                    return
                # if the default is on and the layer is already the default, skip
                if self.layerContents[layerName] == DEFAULT_GLYPHS_DIRNAME and defaultLayer:
                    return
            else:
                # make sure the new layer name doesn't already exist
                if newLayerName is None:
                    newLayerName = DEFAULT_LAYER_NAME
                if newLayerName in self.layerContents:
                    raise UFOLibError("A layer named %s already exists." % newLayerName)
                # make sure the default layer doesn't already exist
                if defaultLayer and DEFAULT_GLYPHS_DIRNAME in self.layerContents.values():
                    raise UFOLibError("A default layer already exists.")
            # get the paths
            oldDirectory = self._findDirectoryForLayerName(layerName)
            if defaultLayer:
                newDirectory = DEFAULT_GLYPHS_DIRNAME
            else:
                existing = {name.lower() for name in self.layerContents.values()}
                newDirectory = userNameToFileName(
                    newLayerName, existing=existing, prefix="glyphs."
                )
            # update the internal mapping
            del self.layerContents[layerName]
            self.layerContents[newLayerName] = newDirectory
            # do the file system copy
            self.fs.movedir(oldDirectory, newDirectory, create=True)

        def deleteGlyphSet(self, layerName):
            """
            Remove the glyph set matching layerName.
            """
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                # ignore deleting glyph sets for UFO1 UFO2 as there are no layers
                # just write the data from the default layer
                return
            foundDirectory = self._findDirectoryForLayerName(layerName)
            self.removePath(foundDirectory, removeEmptyParents=False)
            del self.layerContents[layerName]

        def writeData(self, fileName, data):
            """
            Write data to fileName in the 'data' directory.
            The data must be a bytes string.
            """
            self.writeBytesToPath(f"{DATA_DIRNAME}/{fsdecode(fileName)}", data)

        def removeData(self, fileName):
            """
            Remove the file named fileName from the data directory.
            """
            self.removePath(f"{DATA_DIRNAME}/{fsdecode(fileName)}")

        # /images

        def writeImage(self, fileName, data, validate=None):
            """
            Write data to fileName in the images directory.
            The data must be a valid PNG.
            """
            if validate is None:
                validate = self._validate
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                raise UFOLibError(
                    f"Images are not allowed in UFO {self._formatVersion.major}."
                )
            fileName = fsdecode(fileName)
            if validate:
                valid, error = pngValidator(data=data)
                if not valid:
                    raise UFOLibError(error)
            self.writeBytesToPath(f"{IMAGES_DIRNAME}/{fileName}", data)

        def removeImage(self, fileName, validate=None):  # XXX remove unused 'validate'?
            """
            Remove the file named fileName from the
            images directory.
            """
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                raise UFOLibError(
                    f"Images are not allowed in UFO {self._formatVersion.major}."
                )
            self.removePath(f"{IMAGES_DIRNAME}/{fsdecode(fileName)}")

        def copyImageFromReader(self, reader, sourceFileName, destFileName, validate=None):
            """
            Copy the sourceFileName in the provided UFOReader to destFileName
            in this writer. This uses the most memory efficient method possible
            for copying the data possible.
            """
            if validate is None:
                validate = self._validate
            if self._formatVersion < UFOFormatVersion.FORMAT_3_0:
                raise UFOLibError(
                    f"Images are not allowed in UFO {self._formatVersion.major}."
                )
            sourcePath = f"{IMAGES_DIRNAME}/{fsdecode(sourceFileName)}"
            destPath = f"{IMAGES_DIRNAME}/{fsdecode(destFileName)}"
            self.copyFromReader(reader, sourcePath, destPath)

        def close(self):
            if self._havePreviousFile and self._fileStructure is UFOFileStructure.ZIP:
                # if we are updating an existing zip file, we can now compress the
                # contents of the temporary filesystem in the destination path
                rootDir = os.path.splitext(os.path.basename(self._path))[0] + ".ufo"
                with fs.zipfs.ZipFS(self._path, write=True, encoding="utf-8") as destFS:
                    fs.copy.copy_fs(self.fs, destFS.makedir(rootDir))
            super().close()

    # just an alias, makes it more explicit
    UFOReaderWriter = UFOWriter

    # ----------------
    # Helper Functions
    # ----------------

    def _sniffFileStructure(ufo_path):
        """Return UFOFileStructure.ZIP if the UFO at path 'ufo_path' (str)
        is a zip file, else return UFOFileStructure.PACKAGE if 'ufo_path' is a
        directory.
        Raise UFOLibError if it is a file with unknown structure, or if the path
        does not exist.
        """
        if zipfile.is_zipfile(ufo_path):
            return UFOFileStructure.ZIP
        elif os.path.isdir(ufo_path):
            return UFOFileStructure.PACKAGE
        elif os.path.isfile(ufo_path):
            raise UFOLibError(
                "The specified UFO does not have a known structure: '%s'" % ufo_path
            )
        else:
            raise UFOLibError("No such file or directory: '%s'" % ufo_path)

    def makeUFOPath(path):
        """
        Return a .ufo pathname.

        >>> makeUFOPath("directory/something.ext") == (
        ... 	os.path.join('directory', 'something.ufo'))
        True
        >>> makeUFOPath("directory/something.another.thing.ext") == (
        ... 	os.path.join('directory', 'something.another.thing.ufo'))
        True
        """
        dir, name = os.path.split(path)
        name = ".".join([".".join(name.split(".")[:-1]), "ufo"])
        return os.path.join(dir, name)

    # ----------------------
    # fontinfo.plist Support
    # ----------------------

    # Version Validators

    # There is no version 1 validator and there shouldn't be.
    # The version 1 spec was very loose and there were numerous
    # cases of invalid values.

    def validateFontInfoVersion2ValueForAttribute(attr, value):
        """
        This performs very basic validation of the value for attribute
        following the UFO 2 fontinfo.plist specification. The results
        of this should not be interpretted as *correct* for the font
        that they are part of. This merely indicates that the value
        is of the proper type and, where the specification defines
        a set range of possible values for an attribute, that the
        value is in the accepted range.
        """
        dataValidationDict = fontInfoAttributesVersion2ValueData[attr]
        valueType = dataValidationDict.get("type")
        validator = dataValidationDict.get("valueValidator")
        valueOptions = dataValidationDict.get("valueOptions")
        # have specific options for the validator
        if valueOptions is not None:
            isValidValue = validator(value, valueOptions)
        # no specific options
        else:
            if validator == genericTypeValidator:
                isValidValue = validator(value, valueType)
            else:
                isValidValue = validator(value)
        return isValidValue

    def validateInfoVersion2Data(infoData):
        """
        This performs very basic validation of the value for infoData
        following the UFO 2 fontinfo.plist specification. The results
        of this should not be interpretted as *correct* for the font
        that they are part of. This merely indicates that the values
        are of the proper type and, where the specification defines
        a set range of possible values for an attribute, that the
        value is in the accepted range.
        """
        validInfoData = {}
        for attr, value in list(infoData.items()):
            isValidValue = validateFontInfoVersion2ValueForAttribute(attr, value)
            if not isValidValue:
                raise UFOLibError(f"Invalid value for attribute {attr} ({value!r}).")
            else:
                validInfoData[attr] = value
        return validInfoData

    def validateFontInfoVersion3ValueForAttribute(attr, value):
        """
        This performs very basic validation of the value for attribute
        following the UFO 3 fontinfo.plist specification. The results
        of this should not be interpretted as *correct* for the font
        that they are part of. This merely indicates that the value
        is of the proper type and, where the specification defines
        a set range of possible values for an attribute, that the
        value is in the accepted range.
        """
        dataValidationDict = fontInfoAttributesVersion3ValueData[attr]
        valueType = dataValidationDict.get("type")
        validator = dataValidationDict.get("valueValidator")
        valueOptions = dataValidationDict.get("valueOptions")
        # have specific options for the validator
        if valueOptions is not None:
            isValidValue = validator(value, valueOptions)
        # no specific options
        else:
            if validator == genericTypeValidator:
                isValidValue = validator(value, valueType)
            else:
                isValidValue = validator(value)
        return isValidValue

    def validateInfoVersion3Data(infoData):
        """
        This performs very basic validation of the value for infoData
        following the UFO 3 fontinfo.plist specification. The results
        of this should not be interpretted as *correct* for the font
        that they are part of. This merely indicates that the values
        are of the proper type and, where the specification defines
        a set range of possible values for an attribute, that the
        value is in the accepted range.
        """
        validInfoData = {}
        for attr, value in list(infoData.items()):
            isValidValue = validateFontInfoVersion3ValueForAttribute(attr, value)
            if not isValidValue:
                raise UFOLibError(f"Invalid value for attribute {attr} ({value!r}).")
            else:
                validInfoData[attr] = value
        return validInfoData

    # Value Options

    fontInfoOpenTypeHeadFlagsOptions = list(range(0, 15))
    fontInfoOpenTypeOS2SelectionOptions = [1, 2, 3, 4, 7, 8, 9]
    fontInfoOpenTypeOS2UnicodeRangesOptions = list(range(0, 128))
    fontInfoOpenTypeOS2CodePageRangesOptions = list(range(0, 64))
    fontInfoOpenTypeOS2TypeOptions = [0, 1, 2, 3, 8, 9]

    # Version Attribute Definitions
    # This defines the attributes, types and, in some
    # cases the possible values, that can exist is
    # fontinfo.plist.

    fontInfoAttributesVersion1 = {
        "familyName",
        "styleName",
        "fullName",
        "fontName",
        "menuName",
        "fontStyle",
        "note",
        "versionMajor",
        "versionMinor",
        "year",
        "copyright",
        "notice",
        "trademark",
        "license",
        "licenseURL",
        "createdBy",
        "designer",
        "designerURL",
        "vendorURL",
        "unitsPerEm",
        "ascender",
        "descender",
        "capHeight",
        "xHeight",
        "defaultWidth",
        "slantAngle",
        "italicAngle",
        "widthName",
        "weightName",
        "weightValue",
        "fondName",
        "otFamilyName",
        "otStyleName",
        "otMacName",
        "msCharSet",
        "fondID",
        "uniqueID",
        "ttVendor",
        "ttUniqueID",
        "ttVersion",
    }

    fontInfoAttributesVersion2ValueData = {
        "familyName": dict(type=str),
        "styleName": dict(type=str),
        "styleMapFamilyName": dict(type=str),
        "styleMapStyleName": dict(
            type=str, valueValidator=fontInfoStyleMapStyleNameValidator
        ),
        "versionMajor": dict(type=int),
        "versionMinor": dict(type=int),
        "year": dict(type=int),
        "copyright": dict(type=str),
        "trademark": dict(type=str),
        "unitsPerEm": dict(type=(int, float)),
        "descender": dict(type=(int, float)),
        "xHeight": dict(type=(int, float)),
        "capHeight": dict(type=(int, float)),
        "ascender": dict(type=(int, float)),
        "italicAngle": dict(type=(float, int)),
        "note": dict(type=str),
        "openTypeHeadCreated": dict(
            type=str, valueValidator=fontInfoOpenTypeHeadCreatedValidator
        ),
        "openTypeHeadLowestRecPPEM": dict(type=(int, float)),
        "openTypeHeadFlags": dict(
            type="integerList",
            valueValidator=genericIntListValidator,
            valueOptions=fontInfoOpenTypeHeadFlagsOptions,
        ),
        "openTypeHheaAscender": dict(type=(int, float)),
        "openTypeHheaDescender": dict(type=(int, float)),
        "openTypeHheaLineGap": dict(type=(int, float)),
        "openTypeHheaCaretSlopeRise": dict(type=int),
        "openTypeHheaCaretSlopeRun": dict(type=int),
        "openTypeHheaCaretOffset": dict(type=(int, float)),
        "openTypeNameDesigner": dict(type=str),
        "openTypeNameDesignerURL": dict(type=str),
        "openTypeNameManufacturer": dict(type=str),
        "openTypeNameManufacturerURL": dict(type=str),
        "openTypeNameLicense": dict(type=str),
        "openTypeNameLicenseURL": dict(type=str),
        "openTypeNameVersion": dict(type=str),
        "openTypeNameUniqueID": dict(type=str),
        "openTypeNameDescription": dict(type=str),
        "openTypeNamePreferredFamilyName": dict(type=str),
        "openTypeNamePreferredSubfamilyName": dict(type=str),
        "openTypeNameCompatibleFullName": dict(type=str),
        "openTypeNameSampleText": dict(type=str),
        "openTypeNameWWSFamilyName": dict(type=str),
        "openTypeNameWWSSubfamilyName": dict(type=str),
        "openTypeOS2WidthClass": dict(
            type=int, valueValidator=fontInfoOpenTypeOS2WidthClassValidator
        ),
        "openTypeOS2WeightClass": dict(
            type=int, valueValidator=fontInfoOpenTypeOS2WeightClassValidator
        ),
        "openTypeOS2Selection": dict(
            type="integerList",
            valueValidator=genericIntListValidator,
            valueOptions=fontInfoOpenTypeOS2SelectionOptions,
        ),
        "openTypeOS2VendorID": dict(type=str),
        "openTypeOS2Panose": dict(
            type="integerList", valueValidator=fontInfoVersion2OpenTypeOS2PanoseValidator
        ),
        "openTypeOS2FamilyClass": dict(
            type="integerList", valueValidator=fontInfoOpenTypeOS2FamilyClassValidator
        ),
        "openTypeOS2UnicodeRanges": dict(
            type="integerList",
            valueValidator=genericIntListValidator,
            valueOptions=fontInfoOpenTypeOS2UnicodeRangesOptions,
        ),
        "openTypeOS2CodePageRanges": dict(
            type="integerList",
            valueValidator=genericIntListValidator,
            valueOptions=fontInfoOpenTypeOS2CodePageRangesOptions,
        ),
        "openTypeOS2TypoAscender": dict(type=(int, float)),
        "openTypeOS2TypoDescender": dict(type=(int, float)),
        "openTypeOS2TypoLineGap": dict(type=(int, float)),
        "openTypeOS2WinAscent": dict(type=(int, float)),
        "openTypeOS2WinDescent": dict(type=(int, float)),
        "openTypeOS2Type": dict(
            type="integerList",
            valueValidator=genericIntListValidator,
            valueOptions=fontInfoOpenTypeOS2TypeOptions,
        ),
        "openTypeOS2SubscriptXSize": dict(type=(int, float)),
        "openTypeOS2SubscriptYSize": dict(type=(int, float)),
        "openTypeOS2SubscriptXOffset": dict(type=(int, float)),
        "openTypeOS2SubscriptYOffset": dict(type=(int, float)),
        "openTypeOS2SuperscriptXSize": dict(type=(int, float)),
        "openTypeOS2SuperscriptYSize": dict(type=(int, float)),
        "openTypeOS2SuperscriptXOffset": dict(type=(int, float)),
        "openTypeOS2SuperscriptYOffset": dict(type=(int, float)),
        "openTypeOS2StrikeoutSize": dict(type=(int, float)),
        "openTypeOS2StrikeoutPosition": dict(type=(int, float)),
        "openTypeVheaVertTypoAscender": dict(type=(int, float)),
        "openTypeVheaVertTypoDescender": dict(type=(int, float)),
        "openTypeVheaVertTypoLineGap": dict(type=(int, float)),
        "openTypeVheaCaretSlopeRise": dict(type=int),
        "openTypeVheaCaretSlopeRun": dict(type=int),
        "openTypeVheaCaretOffset": dict(type=(int, float)),
        "postscriptFontName": dict(type=str),
        "postscriptFullName": dict(type=str),
        "postscriptSlantAngle": dict(type=(float, int)),
        "postscriptUniqueID": dict(type=int),
        "postscriptUnderlineThickness": dict(type=(int, float)),
        "postscriptUnderlinePosition": dict(type=(int, float)),
        "postscriptIsFixedPitch": dict(type=bool),
        "postscriptBlueValues": dict(
            type="integerList", valueValidator=fontInfoPostscriptBluesValidator
        ),
        "postscriptOtherBlues": dict(
            type="integerList", valueValidator=fontInfoPostscriptOtherBluesValidator
        ),
        "postscriptFamilyBlues": dict(
            type="integerList", valueValidator=fontInfoPostscriptBluesValidator
        ),
        "postscriptFamilyOtherBlues": dict(
            type="integerList", valueValidator=fontInfoPostscriptOtherBluesValidator
        ),
        "postscriptStemSnapH": dict(
            type="integerList", valueValidator=fontInfoPostscriptStemsValidator
        ),
        "postscriptStemSnapV": dict(
            type="integerList", valueValidator=fontInfoPostscriptStemsValidator
        ),
        "postscriptBlueFuzz": dict(type=(int, float)),
        "postscriptBlueShift": dict(type=(int, float)),
        "postscriptBlueScale": dict(type=(float, int)),
        "postscriptForceBold": dict(type=bool),
        "postscriptDefaultWidthX": dict(type=(int, float)),
        "postscriptNominalWidthX": dict(type=(int, float)),
        "postscriptWeightName": dict(type=str),
        "postscriptDefaultCharacter": dict(type=str),
        "postscriptWindowsCharacterSet": dict(
            type=int, valueValidator=fontInfoPostscriptWindowsCharacterSetValidator
        ),
        "macintoshFONDFamilyID": dict(type=int),
        "macintoshFONDName": dict(type=str),
    }
    fontInfoAttributesVersion2 = set(fontInfoAttributesVersion2ValueData.keys())

    fontInfoAttributesVersion3ValueData = deepcopy(fontInfoAttributesVersion2ValueData)
    fontInfoAttributesVersion3ValueData.update(
        {
            "versionMinor": dict(type=int, valueValidator=genericNonNegativeIntValidator),
            "unitsPerEm": dict(
                type=(int, float), valueValidator=genericNonNegativeNumberValidator
            ),
            "openTypeHeadLowestRecPPEM": dict(
                type=int, valueValidator=genericNonNegativeNumberValidator
            ),
            "openTypeHheaAscender": dict(type=int),
            "openTypeHheaDescender": dict(type=int),
            "openTypeHheaLineGap": dict(type=int),
            "openTypeHheaCaretOffset": dict(type=int),
            "openTypeOS2Panose": dict(
                type="integerList",
                valueValidator=fontInfoVersion3OpenTypeOS2PanoseValidator,
            ),
            "openTypeOS2TypoAscender": dict(type=int),
            "openTypeOS2TypoDescender": dict(type=int),
            "openTypeOS2TypoLineGap": dict(type=int),
            "openTypeOS2WinAscent": dict(
                type=int, valueValidator=genericNonNegativeNumberValidator
            ),
            "openTypeOS2WinDescent": dict(
                type=int, valueValidator=genericNonNegativeNumberValidator
            ),
            "openTypeOS2SubscriptXSize": dict(type=int),
            "openTypeOS2SubscriptYSize": dict(type=int),
            "openTypeOS2SubscriptXOffset": dict(type=int),
            "openTypeOS2SubscriptYOffset": dict(type=int),
            "openTypeOS2SuperscriptXSize": dict(type=int),
            "openTypeOS2SuperscriptYSize": dict(type=int),
            "openTypeOS2SuperscriptXOffset": dict(type=int),
            "openTypeOS2SuperscriptYOffset": dict(type=int),
            "openTypeOS2StrikeoutSize": dict(type=int),
            "openTypeOS2StrikeoutPosition": dict(type=int),
            "openTypeGaspRangeRecords": dict(
                type="dictList", valueValidator=fontInfoOpenTypeGaspRangeRecordsValidator
            ),
            "openTypeNameRecords": dict(
                type="dictList", valueValidator=fontInfoOpenTypeNameRecordsValidator
            ),
            "openTypeVheaVertTypoAscender": dict(type=int),
            "openTypeVheaVertTypoDescender": dict(type=int),
            "openTypeVheaVertTypoLineGap": dict(type=int),
            "openTypeVheaCaretOffset": dict(type=int),
            "woffMajorVersion": dict(
                type=int, valueValidator=genericNonNegativeIntValidator
            ),
            "woffMinorVersion": dict(
                type=int, valueValidator=genericNonNegativeIntValidator
            ),
            "woffMetadataUniqueID": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataUniqueIDValidator
            ),
            "woffMetadataVendor": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataVendorValidator
            ),
            "woffMetadataCredits": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataCreditsValidator
            ),
            "woffMetadataDescription": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataDescriptionValidator
            ),
            "woffMetadataLicense": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataLicenseValidator
            ),
            "woffMetadataCopyright": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataCopyrightValidator
            ),
            "woffMetadataTrademark": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataTrademarkValidator
            ),
            "woffMetadataLicensee": dict(
                type=dict, valueValidator=fontInfoWOFFMetadataLicenseeValidator
            ),
            "woffMetadataExtensions": dict(
                type=list, valueValidator=fontInfoWOFFMetadataExtensionsValidator
            ),
            "guidelines": dict(type=list, valueValidator=guidelinesValidator),
        }
    )
    fontInfoAttributesVersion3 = set(fontInfoAttributesVersion3ValueData.keys())

    # insert the type validator for all attrs that
    # have no defined validator.
    for attr, dataDict in list(fontInfoAttributesVersion2ValueData.items()):
        if "valueValidator" not in dataDict:
            dataDict["valueValidator"] = genericTypeValidator

    for attr, dataDict in list(fontInfoAttributesVersion3ValueData.items()):
        if "valueValidator" not in dataDict:
            dataDict["valueValidator"] = genericTypeValidator

    # Version Conversion Support
    # These are used from converting from version 1
    # to version 2 or vice-versa.

    def _flipDict(d):
        flipped = {}
        for key, value in list(d.items()):
            flipped[value] = key
        return flipped

    fontInfoAttributesVersion1To2 = {
        "menuName": "styleMapFamilyName",
        "designer": "openTypeNameDesigner",
        "designerURL": "openTypeNameDesignerURL",
        "createdBy": "openTypeNameManufacturer",
        "vendorURL": "openTypeNameManufacturerURL",
        "license": "openTypeNameLicense",
        "licenseURL": "openTypeNameLicenseURL",
        "ttVersion": "openTypeNameVersion",
        "ttUniqueID": "openTypeNameUniqueID",
        "notice": "openTypeNameDescription",
        "otFamilyName": "openTypeNamePreferredFamilyName",
        "otStyleName": "openTypeNamePreferredSubfamilyName",
        "otMacName": "openTypeNameCompatibleFullName",
        "weightName": "postscriptWeightName",
        "weightValue": "openTypeOS2WeightClass",
        "ttVendor": "openTypeOS2VendorID",
        "uniqueID": "postscriptUniqueID",
        "fontName": "postscriptFontName",
        "fondID": "macintoshFONDFamilyID",
        "fondName": "macintoshFONDName",
        "defaultWidth": "postscriptDefaultWidthX",
        "slantAngle": "postscriptSlantAngle",
        "fullName": "postscriptFullName",
        # require special value conversion
        "fontStyle": "styleMapStyleName",
        "widthName": "openTypeOS2WidthClass",
        "msCharSet": "postscriptWindowsCharacterSet",
    }
    fontInfoAttributesVersion2To1 = _flipDict(fontInfoAttributesVersion1To2)
    deprecatedFontInfoAttributesVersion2 = set(fontInfoAttributesVersion1To2.keys())

    _fontStyle1To2 = {64: "regular", 1: "italic", 32: "bold", 33: "bold italic"}
    _fontStyle2To1 = _flipDict(_fontStyle1To2)
    # Some UFO 1 files have 0
    _fontStyle1To2[0] = "regular"

    _widthName1To2 = {
        "Ultra-condensed": 1,
        "Extra-condensed": 2,
        "Condensed": 3,
        "Semi-condensed": 4,
        "Medium (normal)": 5,
        "Semi-expanded": 6,
        "Expanded": 7,
        "Extra-expanded": 8,
        "Ultra-expanded": 9,
    }
    _widthName2To1 = _flipDict(_widthName1To2)
    # FontLab's default width value is "Normal".
    # Many format version 1 UFOs will have this.
    _widthName1To2["Normal"] = 5
    # FontLab has an "All" width value. In UFO 1
    # move this up to "Normal".
    _widthName1To2["All"] = 5
    # "medium" appears in a lot of UFO 1 files.
    _widthName1To2["medium"] = 5
    # "Medium" appears in a lot of UFO 1 files.
    _widthName1To2["Medium"] = 5

    _msCharSet1To2 = {
        0: 1,
        1: 2,
        2: 3,
        77: 4,
        128: 5,
        129: 6,
        130: 7,
        134: 8,
        136: 9,
        161: 10,
        162: 11,
        163: 12,
        177: 13,
        178: 14,
        186: 15,
        200: 16,
        204: 17,
        222: 18,
        238: 19,
        255: 20,
    }
    _msCharSet2To1 = _flipDict(_msCharSet1To2)

    # 1 <-> 2

    def convertFontInfoValueForAttributeFromVersion1ToVersion2(attr, value):
        """
        Convert value from version 1 to version 2 format.
        Returns the new attribute name and the converted value.
        If the value is None, None will be returned for the new value.
        """
        # convert floats to ints if possible
        if isinstance(value, float):
            if int(value) == value:
                value = int(value)
        if value is not None:
            if attr == "fontStyle":
                v = _fontStyle1To2.get(value)
                if v is None:
                    raise UFOLibError(
                        f"Cannot convert value ({value!r}) for attribute {attr}."
                    )
                value = v
            elif attr == "widthName":
                v = _widthName1To2.get(value)
                if v is None:
                    raise UFOLibError(
                        f"Cannot convert value ({value!r}) for attribute {attr}."
                    )
                value = v
            elif attr == "msCharSet":
                v = _msCharSet1To2.get(value)
                if v is None:
                    raise UFOLibError(
                        f"Cannot convert value ({value!r}) for attribute {attr}."
                    )
                value = v
        attr = fontInfoAttributesVersion1To2.get(attr, attr)
        return attr, value

    def convertFontInfoValueForAttributeFromVersion2ToVersion1(attr, value):
        """
        Convert value from version 2 to version 1 format.
        Returns the new attribute name and the converted value.
        If the value is None, None will be returned for the new value.
        """
        if value is not None:
            if attr == "styleMapStyleName":
                value = _fontStyle2To1.get(value)
            elif attr == "openTypeOS2WidthClass":
                value = _widthName2To1.get(value)
            elif attr == "postscriptWindowsCharacterSet":
                value = _msCharSet2To1.get(value)
        attr = fontInfoAttributesVersion2To1.get(attr, attr)
        return attr, value

    def _convertFontInfoDataVersion1ToVersion2(data):
        converted = {}
        for attr, value in list(data.items()):
            # FontLab gives -1 for the weightValue
            # for fonts wil no defined value. Many
            # format version 1 UFOs will have this.
            if attr == "weightValue" and value == -1:
                continue
            newAttr, newValue = convertFontInfoValueForAttributeFromVersion1ToVersion2(
                attr, value
            )
            # skip if the attribute is not part of version 2
            if newAttr not in fontInfoAttributesVersion2:
                continue
            # catch values that can't be converted
            if value is None:
                raise UFOLibError(
                    f"Cannot convert value ({value!r}) for attribute {newAttr}."
                )
            # store
            converted[newAttr] = newValue
        return converted

    def _convertFontInfoDataVersion2ToVersion1(data):
        converted = {}
        for attr, value in list(data.items()):
            newAttr, newValue = convertFontInfoValueForAttributeFromVersion2ToVersion1(
                attr, value
            )
            # only take attributes that are registered for version 1
            if newAttr not in fontInfoAttributesVersion1:
                continue
            # catch values that can't be converted
            if value is None:
                raise UFOLibError(
                    f"Cannot convert value ({value!r}) for attribute {newAttr}."
                )
            # store
            converted[newAttr] = newValue
        return converted

    # 2 <-> 3

    _ufo2To3NonNegativeInt = {
        "versionMinor",
        "openTypeHeadLowestRecPPEM",
        "openTypeOS2WinAscent",
        "openTypeOS2WinDescent",
    }
    _ufo2To3NonNegativeIntOrFloat = {
        "unitsPerEm",
    }
    _ufo2To3FloatToInt = {
        "openTypeHeadLowestRecPPEM",
        "openTypeHheaAscender",
        "openTypeHheaDescender",
        "openTypeHheaLineGap",
        "openTypeHheaCaretOffset",
        "openTypeOS2TypoAscender",
        "openTypeOS2TypoDescender",
        "openTypeOS2TypoLineGap",
        "openTypeOS2WinAscent",
        "openTypeOS2WinDescent",
        "openTypeOS2SubscriptXSize",
        "openTypeOS2SubscriptYSize",
        "openTypeOS2SubscriptXOffset",
        "openTypeOS2SubscriptYOffset",
        "openTypeOS2SuperscriptXSize",
        "openTypeOS2SuperscriptYSize",
        "openTypeOS2SuperscriptXOffset",
        "openTypeOS2SuperscriptYOffset",
        "openTypeOS2StrikeoutSize",
        "openTypeOS2StrikeoutPosition",
        "openTypeVheaVertTypoAscender",
        "openTypeVheaVertTypoDescender",
        "openTypeVheaVertTypoLineGap",
        "openTypeVheaCaretOffset",
    }

    def convertFontInfoValueForAttributeFromVersion2ToVersion3(attr, value):
        """
        Convert value from version 2 to version 3 format.
        Returns the new attribute name and the converted value.
        If the value is None, None will be returned for the new value.
        """
        if attr in _ufo2To3FloatToInt:
            try:
                value = round(value)
            except (ValueError, TypeError):
                raise UFOLibError("Could not convert value for %s." % attr)
        if attr in _ufo2To3NonNegativeInt:
            try:
                value = int(abs(value))
            except (ValueError, TypeError):
                raise UFOLibError("Could not convert value for %s." % attr)
        elif attr in _ufo2To3NonNegativeIntOrFloat:
            try:
                v = float(abs(value))
            except (ValueError, TypeError):
                raise UFOLibError("Could not convert value for %s." % attr)
            if v == int(v):
                v = int(v)
            if v != value:
                value = v
        return attr, value

    def convertFontInfoValueForAttributeFromVersion3ToVersion2(attr, value):
        """
        Convert value from version 3 to version 2 format.
        Returns the new attribute name and the converted value.
        If the value is None, None will be returned for the new value.
        """
        return attr, value

    def _convertFontInfoDataVersion3ToVersion2(data):
        converted = {}
        for attr, value in list(data.items()):
            newAttr, newValue = convertFontInfoValueForAttributeFromVersion3ToVersion2(
                attr, value
            )
            if newAttr not in fontInfoAttributesVersion2:
                continue
            converted[newAttr] = newValue
        return converted

    def _convertFontInfoDataVersion2ToVersion3(data):
        converted = {}
        for attr, value in list(data.items()):
            attr, value = convertFontInfoValueForAttributeFromVersion2ToVersion3(
                attr, value
            )
            converted[attr] = value
        return converted

    if __name__ == "__main__":
        import doctest

        doctest.testmod()