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# Source code for asdf._asdf

    import copy
    import datetime
    import io
    import os
    import pathlib
    import time
    import warnings

    from packaging.version import Version

    from . import _compression as mcompression
    from . import _display as display
    from . import _node_info as node_info
    from . import _version as version
    from . import constants, generic_io, reference, schema, treeutil, util, versioning, yamlutil
    from ._block.manager import Manager as BlockManager
    from ._helpers import validate_version
    from .config import config_context, get_config
    from .exceptions import (
        AsdfConversionWarning,
        AsdfDeprecationWarning,
        AsdfWarning,
        DelimiterNotFoundError,
        ValidationError,
    )
    from .extension import Extension, ExtensionProxy, _serialization_context, get_cached_extension_manager
    from .search import AsdfSearchResult
    from .tags.core import AsdfObject, ExtensionMetadata, HistoryEntry, Software
    from .util import NotSet

    def __getattr__(name):
        if name == "SerializationContext":
            warnings.warn(
                "importing SerializationContext from asdf.asdf is deprecated. "
                "Please import SerializationContext from asdf.extension",
                AsdfDeprecationWarning,
            )
            from .extension._serialization_context import SerializationContext

            return SerializationContext

        msg = f"module {__name__!r} has no attribute {name!r}"
        raise AttributeError(msg)

    def _get_asdf_library_info():
        """
        Get information about asdf to include in the asdf_library entry
        in the Tree.
        """
        return Software(
            {
                "name": "asdf",
                "version": version.version,
                "homepage": "http://github.com/asdf-format/asdf",
                "author": "The ASDF Developers",
            },
        )

    class AsdfFile:
        """
        The main class that represents an ASDF file object.
        """

        def __init__(
            self,
            tree=None,
            uri=None,
            extensions=None,
            version=None,
            ignore_version_mismatch=True,
            ignore_unrecognized_tag=False,
            ignore_implicit_conversion=False,
            copy_arrays=False,
            memmap=NotSet,
            lazy_load=True,
            custom_schema=None,
        ):
            """
            Parameters
            ----------
            tree : dict or AsdfFile, optional
                The main tree data in the ASDF file.  Must conform to the
                ASDF schema.

            uri : str, optional
                The URI for this ASDF file.  Used to resolve relative
                references against.  If not provided, will be
                automatically determined from the associated file object,
                if possible and if created from `asdf.open`.

            extensions : object, optional
                Additional extensions to use when reading and writing the file.
                May be an `asdf.extension.Extension` or a `list` of extensions.

            version : str, optional
                The ASDF Standard version.  If not provided, defaults to the
                configured default version.  See `asdf.config.AsdfConfig.default_version`.

            ignore_version_mismatch : bool, optional
                When `True`, do not raise warnings for mismatched schema versions.
                Set to `True` by default.

            ignore_unrecognized_tag : bool, optional
                When `True`, do not raise warnings for unrecognized tags. Set to
                `False` by default.

            ignore_implicit_conversion : bool
                When `True`, do not raise warnings when types in the tree are
                implicitly converted into a serializable object. The motivating
                case for this is currently ``namedtuple``, which cannot be serialized
                as-is.

            copy_arrays : bool, optional
                When `False`, when reading files, attempt to memmap underlying data
                arrays when possible.

            memmap : bool, optional
                When `True`, when reading files, attempt to memmap underlying data
                arrays when possible. When set, this argument will override
                ``copy_arrays``.  When not set, the ``copy_arrays`` will determine
                if arrays are memory mapped or copied. ``copy_arrays`` will be
                deprecated and the default will change in an upcoming asdf version
                which by default will not memory map arrays.

            lazy_load : bool, optional
                When `True` and the underlying file handle is seekable, data
                arrays will only be loaded lazily: i.e. when they are accessed
                for the first time. In this case the underlying file must stay
                open during the lifetime of the tree. Setting to False causes
                all data arrays to be loaded up front, which means that they
                can be accessed even after the underlying file is closed.
                Note: even if ``lazy_load`` is `False`, ``copy_arrays`` is still taken
                into account.

            custom_schema : str, optional
                Path to a custom schema file that will be used for a secondary
                validation pass. This can be used to ensure that particular ASDF
                files follow custom conventions beyond those enforced by the
                standard.
            """
            self._fname = ""

            # Don't use the version setter here; it tries to access
            # the extensions, which haven't been assigned yet.
            if version is None:
                self._version = versioning.AsdfVersion(get_config().default_version)
            else:
                self._version = versioning.AsdfVersion(validate_version(version))

            self._user_extensions = self._process_user_extensions(extensions)
            self._plugin_extensions = self._process_plugin_extensions()
            self._extension_manager = None

            if custom_schema is not None:
                self._custom_schema = schema._load_schema_cached(custom_schema, None, True)
            else:
                self._custom_schema = None

            self._ignore_version_mismatch = ignore_version_mismatch
            self._ignore_unrecognized_tag = ignore_unrecognized_tag
            self._ignore_implicit_conversion = ignore_implicit_conversion

            # Set of (string, string) tuples representing tag version mismatches
            # that we've already warned about for this file.
            self._warned_tag_pairs = set()

            self._file_format_version = None

            # Context of a call to treeutil.walk_and_modify, needed in the AsdfFile
            # in case walk_and_modify is re-entered by extension code (via
            # custom_tree_to_tagged_tree or tagged_tree_to_custom_tree).
            self._tree_modification_context = treeutil._TreeModificationContext()

            self._fd = None
            self._closed = False
            self._external_asdf_by_uri = {}
            # if memmap is set, it overrides copy_arrays
            if memmap is not NotSet:
                copy_arrays = not memmap
            self._blocks = BlockManager(uri=uri, lazy_load=lazy_load, memmap=not copy_arrays)
            # this message is passed into find_references to only warn if
            # a reference was found
            find_ref_warning_msg = (
                "find_references during AsdfFile.__init__ is deprecated. "
                "call AsdfFile.find_references after AsdfFile.__init__"
            )
            if tree is None:
                # Bypassing the tree property here, to avoid validating
                # an empty tree.
                self._tree = AsdfObject()
            elif isinstance(tree, AsdfFile):
                if self.extensions != tree.extensions:
                    # TODO(eslavich): Why not?  What if that's the goal
                    # of copying the file?
                    msg = "Can not copy AsdfFile and change active extensions"
                    raise ValueError(msg)
                self._blocks._uri = tree.uri
                # Set directly to self._tree (bypassing property), since
                # we can assume the other AsdfFile is already valid.
                self._tree = tree.tree
                self.find_references(_warning_msg=find_ref_warning_msg)
            else:
                self._tree = AsdfObject(tree)
                try:
                    self.validate()
                except ValidationError:
                    warnings.warn(
                        "Validation during AsdfFile.__init__ is deprecated. "
                        "Please use AsdfFile.validate to validate the tree",
                        AsdfDeprecationWarning,
                    )
                    raise

                self.find_references(_warning_msg=find_ref_warning_msg)

            self._comments = []

        @property
        def version(self):
            """
            Get this AsdfFile's ASDF Standard version.

            Returns
            -------
            asdf.versioning.AsdfVersion
            """
            return self._version

        @version.setter
        def version(self, value):
            """
            Set this AsdfFile's ASDF Standard version.

            Parameters
            ----------
            value : str or asdf.versioning.AsdfVersion
            """
            self._version = versioning.AsdfVersion(validate_version(value))
            # The new version may not be compatible with the previous
            # set of extensions, so we need to check them again:
            self._user_extensions = self._process_user_extensions(self._user_extensions)
            self._plugin_extensions = self._process_plugin_extensions()
            self._extension_manager = None

        @property
        def version_string(self):
            """
            Get this AsdfFile's ASDF Standard version as a string.

            Returns
            -------
            str
            """
            return str(self._version)

        @property
        def version_map(self):
            return versioning.get_version_map(self.version_string)

        @property
        def extensions(self):
            """
            Get the list of user extensions that are enabled for
            use with this AsdfFile.

            Returns
            -------
            list of asdf.extension.ExtensionProxy
            """
            return self._user_extensions

        @extensions.setter
        def extensions(self, value):
            """
            Set the list of user extensions that are enabled for
            use with this AsdfFile.

            Parameters
            ----------
            value : list of asdf.extension.Extension
            """
            self._user_extensions = self._process_user_extensions(value)
            self._extension_manager = None

        @property
        def extension_manager(self):
            """
            Get the ExtensionManager for this AsdfFile.

            Returns
            -------
            asdf.extension.ExtensionManager
            """
            if self._extension_manager is None:
                self._extension_manager = get_cached_extension_manager(self._user_extensions + self._plugin_extensions)
            return self._extension_manager

        def __enter__(self):
            return self

        def __exit__(self, type_, value, traceback):
            self.close()

        def _check_extensions(self, tree, strict=False):
            """
            Compare the user's installed extensions to metadata in the tree
            and warn when a) an extension is missing or b) an extension is
            present but the file was written with a later version of the
            extension's package.

            Parameters
            ----------
            tree : AsdfObject
                Fully converted tree of custom types.
            strict : bool, optional
                Set to `True` to convert warnings to exceptions.
            """
            if "history" not in tree or not isinstance(tree["history"], dict) or "extensions" not in tree["history"]:
                return

            for extension in tree["history"]["extensions"]:
                installed = None
                for ext in self._user_extensions + self._plugin_extensions:
                    if (
                        extension.extension_uri is not None
                        and extension.extension_uri == ext.extension_uri
                        or extension.extension_uri is None
                        and extension.extension_class in ext.legacy_class_names
                    ):
                        installed = ext
                        break

                filename = f"'{self._fname}' " if self._fname else ""
                if extension.extension_uri is not None:
                    extension_description = f"URI '{extension.extension_uri}'"
                else:
                    extension_description = f"class '{extension.extension_class}'"
                if extension.software is not None:
                    extension_description += (
                        f" (from package {extension.software['name']}=={extension.software['version']})"
                    )

                if installed is None:
                    msg = (
                        f"File {filename}was created with extension "
                        f"{extension_description}, which is not currently installed"
                    )
                    if strict:
                        raise RuntimeError(msg)

                    warnings.warn(msg, AsdfWarning)

                elif extension.software:
                    # Local extensions may not have a real version.  If the package name changed,
                    # then the version sequence may have been reset.
                    if installed.package_version is None or installed.package_name != extension.software["name"]:
                        continue
                    # Compare version in file metadata with installed version
                    if Version(installed.package_version) < Version(extension.software["version"]):
                        msg = (
                            f"File {filename}was created with extension {extension_description}, "
                            f"but older package ({installed.package_name}=={installed.package_version}) is installed."
                        )
                        if strict:
                            raise RuntimeError(msg)

                        warnings.warn(msg, AsdfWarning)

        def _process_plugin_extensions(self):
            """
            Select installed extensions that are compatible with this
            file's ASDF Standard version.

            Returns
            -------
            list of asdf.extension.ExtensionProxy
            """
            return [e for e in get_config().extensions if self.version_string in e.asdf_standard_requirement]

        def _process_user_extensions(self, extensions):
            """
            Validate a list of extensions requested by the user
            add missing extensions registered with the current `AsdfConfig`.

            Parameters
            ----------
            extensions : object
                May be an `asdf.extension.Extension` or a `list` of extensions.

            Returns
            -------
            list of asdf.extension.ExtensionProxy
            """
            if extensions is None:
                extensions = []
            elif isinstance(extensions, (Extension, ExtensionProxy)):
                extensions = [extensions]

            if not isinstance(extensions, list):
                msg = "The extensions parameter must be an extension or list of extensions"
                raise TypeError(msg)

            extensions = [ExtensionProxy.maybe_wrap(e) for e in extensions]

            result = []
            for extension in extensions:
                if self.version_string not in extension.asdf_standard_requirement:
                    warnings.warn(
                        f"Extension {extension} does not support ASDF Standard {self.version_string}.  "
                        "It has been disabled.",
                        AsdfWarning,
                    )
                else:
                    result.append(extension)

            return result

        def _update_extension_history(self, tree, serialization_context):
            """
            Update the extension metadata on this file's tree to reflect
            extensions used during serialization.

            Parameters
            ----------
            serialization_context : asdf.extension.SerializationContext
                The context that was used to serialize the tree.
            """
            if serialization_context.version < versioning.NEW_HISTORY_FORMAT_MIN_VERSION:
                return

            if "history" not in tree:
                tree["history"] = {"extensions": []}
            # Support clients who are still using the old history format
            elif isinstance(tree["history"], list):
                histlist = tree["history"]
                tree["history"] = {"entries": histlist, "extensions": []}
                warnings.warn(
                    "The ASDF history format has changed in order to "
                    "support metadata about extensions. History entries "
                    "should now be stored under tree['history']['entries'].",
                    AsdfWarning,
                )
            elif "extensions" not in tree["history"]:
                tree["history"]["extensions"] = []

            for extension in serialization_context._extensions_used:
                ext_name = extension.class_name
                ext_meta = ExtensionMetadata(extension_class=ext_name)
                if extension.package_name is not None:
                    ext_meta["software"] = Software(name=extension.package_name, version=extension.package_version)
                if extension.extension_uri is not None:
                    ext_meta["extension_uri"] = extension.extension_uri
                if extension.compressors:
                    ext_meta["supported_compression"] = [comp.label.decode("ascii") for comp in extension.compressors]

                for i, entry in enumerate(tree["history"]["extensions"]):
                    # Update metadata about this extension if it already exists
                    if (
                        entry.extension_uri is not None
                        and entry.extension_uri == extension.extension_uri
                        or entry.extension_class in extension.legacy_class_names
                    ):
                        tree["history"]["extensions"][i] = ext_meta
                        break
                else:
                    tree["history"]["extensions"].append(ext_meta)

        @property
        def file_format_version(self):
            if self._file_format_version is None:
                return versioning.AsdfVersion(self.version_map["FILE_FORMAT"])

            return self._file_format_version

        def close(self):
            """
            Close the file handles associated with the `asdf.AsdfFile`.
            """
            if self._fd and not self._closed:
                # This is ok to always do because GenericFile knows
                # whether it "owns" the file and should close it.
                self._fd.close()
                self._fd = None
                self._closed = True
                # as we're closing the file, also empty out the
                # tree so that references to array data can be released
                self._tree = AsdfObject()
            for external in self._external_asdf_by_uri.values():
                external.close()
            self._external_asdf_by_uri.clear()
            self._blocks.close()

        def copy(self):
            return self.__class__(
                copy.deepcopy(self._tree),
                self._blocks._uri,
                self._user_extensions,
            )

        __copy__ = __deepcopy__ = copy

        @property
        def uri(self):
            """
            Get the URI associated with the `AsdfFile`.

            In many cases, it is automatically determined from the file
            handle used to read or write the file.
            """
            return self._blocks._uri

        def resolve_uri(self, uri):
            """
            Resolve a (possibly relative) URI against the URI of this ASDF
            file.  May be overridden by base classes to change how URIs
            are resolved.  This does not apply any ``uri_mapping`` that was
            passed to the constructor.

            Parameters
            ----------
            uri : str
                An absolute or relative URI to resolve against the URI of
                this ASDF file.

            Returns
            -------
            uri : str
                The resolved URI.
            """
            return generic_io.resolve_uri(self.uri, uri)

        def open_external(self, uri, **kwargs):
            """
            Open an external ASDF file, from the given (possibly relative)
            URI.  There is a cache (internal to this ASDF file) that ensures
            each external ASDF file is loaded only once.

            Parameters
            ----------
            uri : str
                An absolute or relative URI to resolve against the URI of
                this ASDF file.

            Returns
            -------
            asdffile : AsdfFile
                The external ASDF file.
            """
            # For a cache key, we want to ignore the "fragment" part.
            base_uri = util.get_base_uri(uri)
            resolved_uri = self.resolve_uri(base_uri)

            # A uri like "#" should resolve back to ourself.  In that case,
            # just return `self`.
            if resolved_uri == "" or resolved_uri == self.uri:
                return self

            asdffile = self._external_asdf_by_uri.get(resolved_uri)
            if asdffile is None:
                asdffile = open_asdf(resolved_uri, mode="r", **kwargs)
                self._external_asdf_by_uri[resolved_uri] = asdffile
            return asdffile

        @property
        def tree(self):
            """
            Get/set the tree of data in the ASDF file.

            When set, the tree will be validated against the ASDF schema.
            """
            if self._closed:
                msg = "Cannot access data from closed ASDF file"
                raise OSError(msg)
            return self._tree

        @tree.setter
        def tree(self, tree):
            asdf_object = AsdfObject(tree)
            # Only perform custom validation if the tree is not empty
            try:
                self._validate(asdf_object, custom=bool(tree))
            except ValidationError:
                warnings.warn(
                    "Validation on tree assignment is deprecated. Please use AsdfFile.validate", AsdfDeprecationWarning
                )
                raise
            self._tree = asdf_object

        def keys(self):
            return self.tree.keys()

        def __getitem__(self, key):
            return self.tree[key]

        def __setitem__(self, key, value):
            self.tree[key] = value

        def __contains__(self, item):
            return item in self.tree

        @property
        def comments(self):
            """
            Get the comments after the header, before the tree.
            """
            return self._comments

        def _validate(self, tree, custom=True, reading=False):
            with self._blocks.options_context():
                # If we're validating on read then the tree
                # is already guaranteed to be in tagged form.
                tagged_tree = tree if reading else yamlutil.custom_tree_to_tagged_tree(tree, self)

                schema.validate(tagged_tree, self, reading=reading)
                # Perform secondary validation pass if requested
                if custom and self._custom_schema:
                    schema.validate(tagged_tree, self, self._custom_schema, reading=reading)

        def validate(self):
            """
            Validate the current state of the tree against the ASDF schema.
            """
            self._validate(self._tree)

        def make_reference(self, path=None):
            """
            Make a new reference to a part of this file's tree, that can be
            assigned as a reference to another tree.

            Parameters
            ----------
            path : list of str and int, optional
                The parts of the path pointing to an item in this tree.
                If omitted, points to the root of the tree.

            Returns
            -------
            reference :
                A reference object.

            Examples
            --------
            For the given AsdfFile ``ff``, add an external reference to the data in
            an external file::

                >>> import asdf
                >>> flat = asdf.open("http://stsci.edu/reference_files/flat.asdf")  # doctest: +SKIP
                >>> ff.tree['flat_field'] = flat.make_reference(['data'])  # doctest: +SKIP
            """
            return reference.make_reference(self, [] if path is None else path)

        def set_array_storage(self, arr, array_storage):
            """
            Set the block type to use for the given array data.

            Parameters
            ----------
            arr : numpy.ndarray
                The array to set.  If multiple views of the array are in
                the tree, only the most recent block type setting will be
                used, since all views share a single block.

            array_storage : str
                Must be one of:

                - ``internal``: The default.  The array data will be
                  stored in a binary block in the same ASDF file.

                - ``external``: Store the data in a binary block in a
                  separate ASDF file.

                - ``inline``: Store the data as YAML inline in the tree.
            """
            self._blocks._set_array_storage(arr, array_storage)

        def get_array_storage(self, arr):
            """
            Get the block type for the given array data.

            Parameters
            ----------
            arr : numpy.ndarray
            """
            return self._blocks._get_array_storage(arr)

        def set_array_compression(self, arr, compression, **compression_kwargs):
            """
            Set the compression to use for the given array data.

            Parameters
            ----------
            arr : numpy.ndarray
                The array to set.  If multiple views of the array are in
                the tree, only the most recent compression setting will be
                used, since all views share a single block.

            compression : str or None
                Must be one of:

                - ``''`` or `None`: no compression

                - ``zlib``: Use zlib compression

                - ``bzp2``: Use bzip2 compression

                - ``lz4``: Use lz4 compression

                - ``input``: Use the same compression as in the file read.
                  If there is no prior file, acts as None.

            """
            self._blocks._set_array_compression(arr, compression, **compression_kwargs)

        def get_array_compression(self, arr):
            """
            Get the compression type for the given array data.

            Parameters
            ----------
            arr : numpy.ndarray

            Returns
            -------
            compression : str or None
            """
            return self._blocks._get_array_compression(arr)

        def get_array_compression_kwargs(self, arr):
            """ """
            return self._blocks._get_array_compression_kwargs(arr)

        @classmethod
        def _parse_header_line(cls, line):
            """
            Parses the header line in a ASDF file to obtain the ASDF version.
            """
            parts = line.split()
            if len(parts) != 2 or parts[0] != constants.ASDF_MAGIC:
                msg = "Does not appear to be a ASDF file."
                raise ValueError(msg)

            try:
                version = versioning.AsdfVersion(parts[1].decode("ascii"))
            except ValueError as err:
                msg = f"Unparsable version in ASDF file: {parts[1]}"
                raise ValueError(msg) from err

            return version

        @classmethod
        def _read_comment_section(cls, fd):
            """
            Reads the comment section, between the header line and the
            Tree or first block.
            """
            content = fd.read_until(
                b"(%YAML)|(" + constants.BLOCK_MAGIC + b")",
                5,
                "start of content",
                include=False,
                exception=False,
            )

            comments = []

            lines = content.splitlines()
            for line in lines:
                if not line.startswith(b"#"):
                    msg = "Invalid content between header and tree"
                    raise ValueError(msg)
                comments.append(line[1:].strip())

            return comments

        @classmethod
        def _find_asdf_version_in_comments(cls, comments):
            for comment in comments:
                parts = comment.split()
                if len(parts) == 2 and parts[0] == constants.ASDF_STANDARD_COMMENT:
                    try:
                        version = versioning.AsdfVersion(parts[1].decode("ascii"))
                    except ValueError:
                        pass
                    else:
                        return version

            return None

        @classmethod
        def _open_asdf(
            cls,
            self,
            fd,
            validate_checksums=False,
            extensions=None,
            _get_yaml_content=False,
            _force_raw_types=False,
            strict_extension_check=False,
            ignore_missing_extensions=False,
        ):
            """Attempt to populate AsdfFile data from file-like object"""

            if strict_extension_check and ignore_missing_extensions:
                msg = "'strict_extension_check' and 'ignore_missing_extensions' are incompatible options"
                raise ValueError(msg)

            with config_context():
                # validate_checksums (unlike memmap and lazy_load) is provided
                # here instead of in __init__
                self._blocks._validate_checksums = validate_checksums
                self._mode = fd.mode
                self._fd = fd
                if self._fd._uri:
                    self._blocks._uri = self._fd._uri
                # The filename is currently only used for tracing warning information
                self._fname = self._fd._uri if self._fd._uri else ""
                try:
                    header_line = fd.read_until(b"\r?\n", 2, "newline", include=True)
                except DelimiterNotFoundError as e:
                    msg = "Does not appear to be a ASDF file."
                    raise ValueError(msg) from e
                self._file_format_version = cls._parse_header_line(header_line)
                self.version = self._file_format_version

                self._comments = cls._read_comment_section(fd)

                version = cls._find_asdf_version_in_comments(self._comments)
                if version is not None:
                    self.version = version

                # Now that version is set for good, we can add any additional
                # extensions, which may have narrow ASDF Standard version
                # requirements.
                if extensions:
                    self.extensions = extensions

                yaml_token = fd.read(4)
                tree = None
                if yaml_token == b"%YAM":
                    reader = fd.reader_until(
                        constants.YAML_END_MARKER_REGEX,
                        7,
                        "End of YAML marker",
                        include=True,
                        initial_content=yaml_token,
                    )

                    # For testing: just return the raw YAML content
                    if _get_yaml_content:
                        yaml_content = reader.read()
                        fd.close()
                        return yaml_content

                    # We parse the YAML content into basic data structures
                    # now, but we don't do anything special with it until
                    # after the blocks have been read
                    tree = yamlutil.load_tree(reader)
                    self._blocks.read(fd)
                elif yaml_token == constants.BLOCK_MAGIC:
                    # this file has only blocks and we're already read the first block magic
                    self._blocks.read(fd, after_magic=True)
                elif yaml_token != b"":
                    msg = "ASDF file appears to contain garbage after header."
                    raise OSError(msg)

                if tree is None:
                    # At this point the tree should be tagged, but we want it to be
                    # tagged with the core/asdf version appropriate to this file's
                    # ASDF Standard version.  We're using custom_tree_to_tagged_tree
                    # to select the correct tag for us.
                    tree = yamlutil.custom_tree_to_tagged_tree(AsdfObject(), self)

                find_ref_warning_msg = "find_references during open is deprecated. call AsdfFile.find_references after open"
                tree = reference.find_references(tree, self, _warning_msg=find_ref_warning_msg)

                if self.version <= versioning.FILL_DEFAULTS_MAX_VERSION and get_config().legacy_fill_schema_defaults:
                    schema.fill_defaults(tree, self, reading=True)

                if get_config().validate_on_read:
                    try:
                        self._validate(tree, reading=True)
                    except ValidationError:
                        self.close()
                        raise

                tree = yamlutil.tagged_tree_to_custom_tree(tree, self, _force_raw_types)

                if not (ignore_missing_extensions or _force_raw_types):
                    self._check_extensions(tree, strict=strict_extension_check)

                self._tree = tree

                return self

        @classmethod
        def _open_impl(
            cls,
            self,
            fd,
            uri=None,
            mode="r",
            validate_checksums=False,
            extensions=None,
            _get_yaml_content=False,
            _force_raw_types=False,
            strict_extension_check=False,
            ignore_missing_extensions=False,
        ):
            """Attempt to open file-like object as an AsdfFile"""
            close_on_fail = isinstance(fd, (str, pathlib.Path))
            generic_file = generic_io.get_file(fd, mode=mode, uri=uri)
            try:
                return cls._open_asdf(
                    self,
                    generic_file,
                    validate_checksums=validate_checksums,
                    extensions=extensions,
                    _get_yaml_content=_get_yaml_content,
                    _force_raw_types=_force_raw_types,
                    strict_extension_check=strict_extension_check,
                    ignore_missing_extensions=ignore_missing_extensions,
                )
            except Exception:
                if close_on_fail:
                    generic_file.close()
                raise

        def _write_tree(self, tree, fd, pad_blocks):
            fd.write(constants.ASDF_MAGIC)
            fd.write(b" ")
            fd.write(self.version_map["FILE_FORMAT"].encode("ascii"))
            fd.write(b"\n")

            fd.write(b"#")
            fd.write(constants.ASDF_STANDARD_COMMENT)
            fd.write(b" ")
            fd.write(self.version_string.encode("ascii"))
            fd.write(b"\n")

            if len(tree):
                serialization_context = self._create_serialization_context(_serialization_context.BlockAccess.WRITE)

                for compression in self._blocks.get_output_compressions():
                    # lookup extension
                    compressor = mcompression._get_compressor_from_extensions(compression, return_extension=True)
                    if compressor is not None:
                        # mark it as used
                        serialization_context._mark_extension_used(compressor[1])

                def _tree_finalizer(tagged_tree):
                    """
                    The list of extensions used is not known until after
                    serialization, so we're using a hook provided by
                    yamlutil.dump_tree to update extension metadata
                    after the tree has been converted to tagged objects.
                    """
                    self._update_extension_history(tree, serialization_context)
                    if "history" in tree:
                        tagged_tree["history"] = yamlutil.custom_tree_to_tagged_tree(
                            tree["history"],
                            self,
                            _serialization_context=serialization_context,
                        )
                    else:
                        tagged_tree.pop("history", None)

                yamlutil.dump_tree(
                    tree,
                    fd,
                    self,
                    tree_finalizer=_tree_finalizer,
                    _serialization_context=serialization_context,
                )

            if pad_blocks:
                padding = util.calculate_padding(fd.tell(), pad_blocks, fd.block_size)
                fd.fast_forward(padding)

        def _pre_write(self, fd):
            pass

        def _post_write(self, fd):
            pass

        def _serial_write(self, fd, pad_blocks, include_block_index):
            with self._blocks.write_context(fd):
                self._pre_write(fd)
                try:
                    # prep a tree for a writing
                    tree = copy.copy(self._tree)
                    tree["asdf_library"] = _get_asdf_library_info()
                    if "history" in self._tree:
                        tree["history"] = copy.deepcopy(self._tree["history"])

                    self._write_tree(tree, fd, pad_blocks)
                    self._blocks.write(pad_blocks, include_block_index)
                finally:
                    self._post_write(fd)

        def update(
            self,
            all_array_storage=NotSet,
            all_array_compression=NotSet,
            compression_kwargs=NotSet,
            pad_blocks=False,
            include_block_index=True,
            version=None,
        ):
            """
            Update the file on disk in place.

            Parameters
            ----------
            all_array_storage : string, optional
                If provided, override the array storage type of all blocks
                in the file immediately before writing.  Must be one of:

                - ``internal``: The default.  The array data will be
                  stored in a binary block in the same ASDF file.

                - ``external``: Store the data in a binary block in a
                  separate ASDF file.

                - ``inline``: Store the data as YAML inline in the tree.

            all_array_compression : string, optional
                If provided, set the compression type on all binary blocks
                in the file.  Must be one of:

                - ``''`` or `None`: No compression.

                - ``zlib``: Use zlib compression.

                - ``bzp2``: Use bzip2 compression.

                - ``lz4``: Use lz4 compression.

                - ``input``: Use the same compression as in the file read.
                  If there is no prior file, acts as None

            compression_kwargs : dict, optional
                If provided, set this as the compression keyword arguments
                for all binary blocks in the file.

            pad_blocks : float or bool, optional
                Add extra space between blocks to allow for updating of
                the file.  If `False` (default), add no padding (always
                return 0).  If `True`, add a default amount of padding of
                10% If a float, it is a factor to multiple content_size by
                to get the new total size.

            include_block_index : bool, optional
                If `False`, don't include a block index at the end of the
                file.  (Default: `True`)  A block index is never written
                if the file has a streamed block.

            version : str, optional
                Update the ASDF Standard version of this AsdfFile before
                writing.
            """

            with config_context() as config:
                if all_array_storage is not NotSet:
                    config.all_array_storage = all_array_storage
                if all_array_compression is not NotSet:
                    config.all_array_compression = all_array_compression
                if compression_kwargs is not NotSet:
                    config.all_array_compression_kwargs = compression_kwargs

                fd = self._fd

                if fd is None:
                    msg = "Can not update, since there is no associated file"
                    raise ValueError(msg)

                if not fd.writable():
                    msg = (
                        "Can not update, since associated file is read-only. Make "
                        "sure that the AsdfFile was opened with mode='rw' and the "
                        "underlying file handle is writable."
                    )
                    raise OSError(msg)

                if not fd.seekable():
                    msg = "Can not update, since associated file is not seekable"
                    raise OSError(msg)

                if version is not None:
                    self.version = version

                # flush all pending memmap writes
                if fd.can_memmap():
                    fd.flush_memmap()

                def rewrite():
                    self._fd.seek(0)
                    self._serial_write(self._fd, pad_blocks, include_block_index)
                    self._fd.truncate()
                    if self._fd.can_memmap():
                        self._fd.close_memmap()

                # if we have no read blocks, we can just call write_to as no internal blocks are reused
                if len(self._blocks.blocks) == 0:
                    rewrite()
                    return

                # if we have all external blocks, we can just call write_to as no internal blocks are reused
                if config.all_array_storage == "external":
                    rewrite()
                    return

                self._pre_write(fd)
                try:
                    self._tree["asdf_library"] = _get_asdf_library_info()

                    # prepare block manager for writing
                    with self._blocks.write_context(self._fd, copy_options=False):
                        # write out tree to temporary buffer
                        tree_fd = generic_io.get_file(io.BytesIO(), mode="rw")
                        self._write_tree(self._tree, tree_fd, False)
                        new_tree_size = tree_fd.tell()

                        # update blocks
                        self._blocks.update(new_tree_size, pad_blocks, include_block_index)
                        end_of_file = self._fd.tell()

                    # now write the tree
                    self._fd.seek(0)
                    tree_fd.seek(0)
                    self._fd.write(tree_fd.read())
                    self._fd.flush()

                    # close memmap to trigger arrays to reload themselves
                    self._fd.seek(end_of_file)
                    self._fd.truncate()
                    if self._fd.can_memmap():
                        self._fd.close_memmap()

                finally:
                    self._post_write(fd)

        def write_to(
            self,
            fd,
            all_array_storage=NotSet,
            all_array_compression=NotSet,
            compression_kwargs=NotSet,
            pad_blocks=False,
            include_block_index=True,
            version=None,
        ):
            """
            Write the ASDF file to the given file-like object.

            `write_to` does not change the underlying file descriptor in
            the `asdf.AsdfFile` object, but merely copies the content to a new
            file.

            Parameters
            ----------
            fd : string or file-like object
                May be a string path to a file, or a Python file-like
                object.  If a string path, the file is automatically
                closed after writing.  If not a string path, it is the
                caller's responsibility to close the object.

            all_array_storage : string, optional
                If provided, override the array storage type of all blocks
                in the file immediately before writing.  Must be one of:

                - ``internal``: The default.  The array data will be
                  stored in a binary block in the same ASDF file.

                - ``external``: Store the data in a binary block in a
                  separate ASDF file.

                - ``inline``: Store the data as YAML inline in the tree.

            all_array_compression : string, optional
                If provided, set the compression type on all binary blocks
                in the file.  Must be one of:

                - ``''`` or `None`: No compression.

                - ``zlib``: Use zlib compression.

                - ``bzp2``: Use bzip2 compression.

                - ``lz4``: Use lz4 compression.

                - ``input``: Use the same compression as in the file read.
                  If there is no prior file, acts as None.

            compression_kwargs : dict, optional
                If provided, set this as the compression keyword arguments
                for all binary blocks in the file.

            pad_blocks : float or bool, optional
                Add extra space between blocks to allow for updating of
                the file.  If `False` (default), add no padding (always
                return 0).  If `True`, add a default amount of padding of
                10% If a float, it is a factor to multiple content_size by
                to get the new total size.

            include_block_index : bool, optional
                If `False`, don't include a block index at the end of the
                file.  (Default: `True`)  A block index is never written
                if the file has a streamed block.

            version : str, optional
                Update the ASDF Standard version of this AsdfFile before
                writing.
            """
            with config_context() as config:
                if all_array_storage is not NotSet:
                    config.all_array_storage = all_array_storage
                if all_array_compression is not NotSet:
                    config.all_array_compression = all_array_compression
                if compression_kwargs is not NotSet:
                    config.all_array_compression_kwargs = compression_kwargs

                if version is not None:
                    previous_version = self.version
                    self.version = version

                try:
                    with generic_io.get_file(fd, mode="w") as fd:
                        self._serial_write(fd, pad_blocks, include_block_index)
                finally:
                    if version is not None:
                        self.version = previous_version

        def find_references(self, _warning_msg=False):
            """
            Finds all external "JSON References" in the tree and converts
            them to ``reference.Reference`` objects.
            """
            # Set directly to self._tree, since it doesn't need to be re-validated.
            self._tree = reference.find_references(self._tree, self, _warning_msg=_warning_msg)

        def resolve_references(self, **kwargs):
            """
            Finds all external "JSON References" in the tree, loads the
            external content, and places it directly in the tree.  Saving
            a ASDF file after this operation means it will have no
            external references, and will be completely self-contained.
            """
            if len(kwargs):
                warnings.warn("Passing kwargs to resolve_references is deprecated and does nothing", AsdfDeprecationWarning)
            self._tree = reference.resolve_references(self._tree, self)
            try:
                self.validate()
            except ValidationError:
                warnings.warn(
                    "Validation during resolve_references is deprecated. "
                    "Please use AsdfFile.validate after resolve_references to validate the resolved tree",
                    AsdfDeprecationWarning,
                )
                raise

        def resolve_and_inline(self):
            """
            Resolves all external references and inlines all data.  This
            produces something that, when saved, is a 100% valid YAML
            file.
            """
            warnings.warn(
                "resolve_and_inline is deprecated. "
                "Use AsdfFile.resolve_references and all_array_storage=inline "
                "during AsdfFile.write_to",
                AsdfDeprecationWarning,
            )
            self.resolve_references()
            for b in self._blocks.blocks:
                self.set_array_storage(b.data, "inline")

        def fill_defaults(self):
            """
            Fill in any values that are missing in the tree using default
            values from the schema.
            """
            tree = yamlutil.custom_tree_to_tagged_tree(self._tree, self)
            schema.fill_defaults(tree, self)
            self._tree = yamlutil.tagged_tree_to_custom_tree(tree, self)

        def remove_defaults(self):
            """
            Remove any values in the tree that are the same as the default
            values in the schema
            """
            tree = yamlutil.custom_tree_to_tagged_tree(self._tree, self)
            schema.remove_defaults(tree, self)
            self._tree = yamlutil.tagged_tree_to_custom_tree(tree, self)

        def add_history_entry(self, description, software=None):
            """
            Add an entry to the history list.

            Parameters
            ----------
            description : str
                A description of the change.

            software : dict or list of dict
                A description of the software used.  It should not include
                asdf itself, as that is automatically notated in the
                ``asdf_library`` entry.

                Each dict must have the following keys:

                - ``name``: The name of the software
                - ``author``: The author or institution that produced the software
                - ``homepage``: A URI to the homepage of the software
                - ``version``: The version of the software
            """
            if isinstance(software, list):
                software = [Software(x) for x in software]
            elif software is not None:
                software = Software(software)

            time_ = datetime.datetime.fromtimestamp(
                int(os.environ.get("SOURCE_DATE_EPOCH", time.time())), datetime.timezone.utc
            )

            entry = HistoryEntry(
                {
                    "description": description,
                    "time": time_,
                },
            )

            if software is not None:
                entry["software"] = software

            if self.version >= versioning.NEW_HISTORY_FORMAT_MIN_VERSION:
                if "history" not in self.tree:
                    self.tree["history"] = {"entries": []}
                elif "entries" not in self.tree["history"]:
                    self.tree["history"]["entries"] = []

                self.tree["history"]["entries"].append(entry)

                try:
                    self.validate()
                except Exception:
                    self.tree["history"]["entries"].pop()
                    raise
            else:
                if "history" not in self.tree:
                    self.tree["history"] = []

                self.tree["history"].append(entry)

                try:
                    self.validate()
                except Exception:
                    self.tree["history"].pop()
                    raise

        def get_history_entries(self):
            """
            Get a list of history entries from the file object.

            Returns
            -------
            entries : list
                A list of history entries.
            """

            if "history" not in self.tree:
                return []

            if isinstance(self.tree["history"], list):
                return self.tree["history"]

            if "entries" in self.tree["history"]:
                return self.tree["history"]["entries"]

            return []

        def schema_info(self, key="description", path=None, preserve_list=True, refresh_extension_manager=False):
            """
            Get a nested dictionary of the schema information for a given key, relative to the path.

            Parameters
            ----------
            key : str
                The key to look up.
                Default: "description"
            path : str or asdf.search.AsdfSearchResult
                A dot-separated path to the parameter to find the key information on or
                an `asdf.search.AsdfSearchResult` object.
                Default = None (full dictionary).
            preserve_list : bool
                If True, then lists are preserved. Otherwise, they are turned into dicts.
            refresh_extension_manager : bool
                If `True`, refresh the extension manager before looking up the
                key.  This is useful if you want to make sure that the schema
                data for a given key is up to date.
            """

            if isinstance(path, AsdfSearchResult):
                return path.schema_info(
                    key,
                    preserve_list=preserve_list,
                    refresh_extension_manager=refresh_extension_manager,
                )

            return node_info.collect_schema_info(
                key,
                path,
                self.tree,
                preserve_list=preserve_list,
                refresh_extension_manager=refresh_extension_manager,
            )

        def info(
            self,
            max_rows=display.DEFAULT_MAX_ROWS,
            max_cols=display.DEFAULT_MAX_COLS,
            show_values=display.DEFAULT_SHOW_VALUES,
            refresh_extension_manager=False,
        ):
            """
            Print a rendering of this file's tree to stdout.

            Parameters
            ----------
            max_rows : int, tuple, or None, optional
                Maximum number of lines to print.  Nodes that cannot be
                displayed will be elided with a message.
                If int, constrain total number of displayed lines.
                If tuple, constrain lines per node at the depth corresponding \
                    to the tuple index.
                If None, display all lines.

            max_cols : int or None, optional
                Maximum length of line to print.  Nodes that cannot
                be fully displayed will be truncated with a message.
                If int, constrain length of displayed lines.
                If None, line length is unconstrained.

            show_values : bool, optional
                Set to False to disable display of primitive values in
                the rendered tree.
            """

            lines = display.render_tree(
                self.tree,
                max_rows=max_rows,
                max_cols=max_cols,
                show_values=show_values,
                identifier="root",
                refresh_extension_manager=refresh_extension_manager,
            )
            print("\n".join(lines))

        def search(self, key=NotSet, type_=NotSet, value=NotSet, filter_=None):
            """
            Search this file's tree.

            Parameters
            ----------
            key : NotSet, str, or any other object
                Search query that selects nodes by dict key or list index.
                If NotSet, the node key is unconstrained.
                If str, the input is searched among keys/indexes as a regular
                expression pattern.
                If any other object, node's key or index must equal the queried key.

            type_ : NotSet, str, or builtins.type
                Search query that selects nodes by type.
                If NotSet, the node type is unconstrained.
                If str, the input is searched among (fully qualified) node type
                names as a regular expression pattern.
                If builtins.type, the node must be an instance of the input.

            value : NotSet, str, or any other object
                Search query that selects nodes by value.
                If NotSet, the node value is unconstrained.
                If str, the input is searched among values as a regular
                expression pattern.
                If any other object, node's value must equal the queried value.

            filter_ : callable
                Callable that filters nodes by arbitrary criteria.
                The callable accepts one or two arguments:

                - the node
                - the node's list index or dict key (optional)

                and returns True to retain the node, or False to remove it from
                the search results.

            Returns
            -------
            asdf.search.AsdfSearchResult
                the result of the search
            """
            result = AsdfSearchResult(["root"], self.tree)
            return result.search(key=key, type_=type_, value=value, filter_=filter_)

        # This function is called from within TypeIndex when deserializing
        # the tree for this file.  It is kept here so that we can keep
        # state on the AsdfFile and prevent a flood of warnings for the
        # same tag.
        def _warn_tag_mismatch(self, tag, best_tag):
            if not self._ignore_version_mismatch and (tag, best_tag) not in self._warned_tag_pairs:
                message = (
                    f"No explicit ExtensionType support provided for tag '{tag}'. "
                    f"The ExtensionType subclass for tag '{best_tag}' will be used instead. "
                    "This fallback behavior will be removed in asdf 3.0."
                )
                warnings.warn(message, AsdfConversionWarning)
                self._warned_tag_pairs.add((tag, best_tag))

        # This function is called from within yamlutil methods to create
        # a context when one isn't explicitly passed in.
        def _create_serialization_context(self, operation=_serialization_context.BlockAccess.NONE):
            return _serialization_context.create(self, operation)

    def open_asdf(
        fd,
        uri=None,
        mode=None,
        validate_checksums=False,
        extensions=None,
        ignore_version_mismatch=True,
        ignore_unrecognized_tag=False,
        _force_raw_types=False,
        copy_arrays=False,
        memmap=NotSet,
        lazy_load=True,
        custom_schema=None,
        strict_extension_check=False,
        ignore_missing_extensions=False,
        _get_yaml_content=False,
    ):
        """
        Open an existing ASDF file.

        Parameters
        ----------
        fd : string or file-like object
            May be a string ``file`` or ``http`` URI, or a Python
            file-like object.

        uri : string, optional
            The URI of the file.  Only required if the URI can not be
            automatically determined from ``fd``.

        mode : string, optional
            The mode to open the file in.  Must be ``r`` (default) or
            ``rw``.

        validate_checksums : bool, optional
            If `True`, validate the blocks against their checksums.
            Requires reading the entire file, so disabled by default.

        extensions : object, optional
            Additional extensions to use when reading and writing the file.
            May be an `asdf.extension.Extension` or a `list` of extensions.

        ignore_version_mismatch : bool, optional
            When `True`, do not raise warnings for mismatched schema versions.
            Set to `True` by default.

        ignore_unrecognized_tag : bool, optional
            When `True`, do not raise warnings for unrecognized tags. Set to
            `False` by default.

        copy_arrays : bool, optional
            When `False`, when reading files, attempt to memmap underlying data
            arrays when possible.

        memmap : bool, optional
            When `True`, when reading files, attempt to memmap underlying data
            arrays when possible. When set, this argument will override
            ``copy_arrays``.  When not set, the ``copy_arrays`` will determine
            if arrays are memory mapped or copied. ``copy_arrays`` will be
            deprecated and the default will change in an upcoming asdf version
            which by default will not memory map arrays.

        lazy_load : bool, optional
            When `True` and the underlying file handle is seekable, data
            arrays will only be loaded lazily: i.e. when they are accessed
            for the first time. In this case the underlying file must stay
            open during the lifetime of the tree. Setting to False causes
            all data arrays to be loaded up front, which means that they
            can be accessed even after the underlying file is closed.
            Note: even if ``lazy_load`` is `False`, ``memmap`` is still taken
            into account.

        custom_schema : str, optional
            Path to a custom schema file that will be used for a secondary
            validation pass. This can be used to ensure that particular ASDF
            files follow custom conventions beyond those enforced by the
            standard.

        strict_extension_check : bool, optional
            When `True`, if the given ASDF file contains metadata about the
            extensions used to create it, and if those extensions are not
            installed, opening the file will fail. When `False`, opening a file
            under such conditions will cause only a warning. Defaults to
            `False`.

        ignore_missing_extensions : bool, optional
            When `True`, do not raise warnings when a file is read that
            contains metadata about extensions that are not available. Defaults
            to `False`.

        Returns
        -------
        asdffile : AsdfFile
            The new AsdfFile object.
        """

        if mode is not None and mode not in ["r", "rw"]:
            msg = f"Unrecognized asdf mode '{mode}'. Must be either 'r' or 'rw'"
            raise ValueError(msg)

        if mode is None:
            if isinstance(fd, io.IOBase):
                mode = "rw" if fd.writable() else "r"
            elif isinstance(fd, generic_io.GenericFile):
                mode = fd.mode
            else:
                # This is the safest assumption for the default fallback
                mode = "r"

        instance = AsdfFile(
            ignore_version_mismatch=ignore_version_mismatch,
            ignore_unrecognized_tag=ignore_unrecognized_tag,
            copy_arrays=copy_arrays,
            memmap=memmap,
            lazy_load=lazy_load,
            custom_schema=custom_schema,
        )

        return AsdfFile._open_impl(
            instance,
            fd,
            uri=uri,
            mode=mode,
            validate_checksums=validate_checksums,
            extensions=extensions,
            _get_yaml_content=_get_yaml_content,
            _force_raw_types=_force_raw_types,
            strict_extension_check=strict_extension_check,
            ignore_missing_extensions=ignore_missing_extensions,
        )