Source code for pyface.data_view.i_data_wrapper

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from codecs import decode, encode
from functools import partial
from typing import Any as TAny, Callable as TCallable, NamedTuple

from traits.api import Any, HasStrictTraits, Interface


[docs]class DataFormat(NamedTuple): """ Information about a mimetype and serializers. Simple namedtuple-based class that stores the mimetype, serializer and deserializer together. """ #: The mimetype of the data. mimetype: str #: A callable that serializes this format. It should take an python #: object of a supported type, and return a bytestring. serialize: TCallable[[TAny], bytes] #: A callable that deserializes this format. It should take a #: bytestring and return the extracted object. deserialize: TCallable[[bytes], TAny]
[docs]def text_format(encoding='utf-8', mimetype='text/plain'): """ DataFormat factory for text mimetypes. """ return DataFormat( mimetype=mimetype, serialize=partial(encode, encoding=encoding), deserialize=partial(decode, encoding=encoding), )
[docs]class IDataWrapper(Interface): """ Wrapper around polymorphic toolkit data object containing mimedata. To support clipboard and drag and drop operations, toolkits need a way of generically representing data in multiple formats. This is a wrapper class that provides a toolkit independent intreface to these classes which allow the exchange of data, with types specified by MIME types. """ #: The toolkit data object. toolkit_data = Any()
[docs] def mimetypes(self): """ Return a set of mimetypes holding data. Returns ------- mimetypes : set of str The set of mimetypes currently storing data in the toolkit data object. """ pass
[docs] def has_format(self, format): """ Whether or not a particular format has available data. Parameters ---------- format : DataFormat A data format object. Returns ------- has_format : bool Whether or not there is data associated with that format in the underlying toolkit object. """ raise NotImplementedError()
[docs] def get_format(self, format): """ The decoded data associted with the format. Parameters ---------- format : DataFormat A data format object. Returns ------- data : any The data decoded for the given format. """ raise NotImplementedError()
[docs] def set_format(self, format, data): """ Encode and set data for the format. Parameters ---------- format : DataFormat A data format object. data : any The data to be encoded and stored. """ raise NotImplementedError()
[docs] def get_mimedata(self, mimetype): """ Get raw data for the given media type. Parameters ---------- mimetype : str The mime media type to be extracted. Returns ------- mimedata : bytes The mime media data as bytes. """ raise NotImplementedError()
[docs] def set_mimedata(self, mimetype, mimedata): """ Set raw data for the given media type. Parameters ---------- mimetype : str The mime media type to be extracted. mimedata : bytes The mime media data encoded as bytes.. """ raise NotImplementedError()
[docs]class MDataWrapper(HasStrictTraits): """ Mixin class for DataWrappers. This provides standard methods for using DataFormat objects, but not the low-level communication with the underlying toolkit. """
[docs] def has_format(self, format): """ Whether or not a particular format has available data. Parameters ---------- format : DataFormat A data format object. Returns ------- has_format : bool Whether or not there is data associated with that format in the underlying toolkit object. """ return format.mimetype in self.mimetypes()
[docs] def get_format(self, format): """ The decoded data associted with the format. Parameters ---------- format : DataFormat A data format object. Returns ------- data : any The data decoded for the given format. """ return format.deserialize(self.get_mimedata(format.mimetype))
[docs] def set_format(self, format, data): """ Encode and set data for the format. Parameters ---------- format : DataFormat A data format object. data : any The data to be encoded and stored. """ self.set_mimedata(format.mimetype, format.serialize(data))