Reduce duplication between `_generate_cubes` and `load_meshes`

[trexfeathers]

An artifact from when load_meshes was still experimental. Code should be factored out so that both these routines can call the same convenience.

Code

iris/lib/iris/loading.py

Lines 74 to 105 in 3432ca1

	def _generate_cubes(uris, callback, constraints):
	import iris.io
	"""Return a generator of cubes given the URIs and a callback."""
	if (
	isinstance(uris, str)
	or hasattr(uris, "fromcdl")
	or not isinstance(uris, Iterable)
	):
	# Make a string, Dataset, or other single item, into an iterable.
	uris = [uris]
	# Group collections of uris by their iris handler
	# Create list of tuples relating schemes to part names
	uri_tuples = sorted(iris.io.decode_uri(uri) for uri in uris)
	for scheme, groups in itertools.groupby(uri_tuples, key=lambda x: x[0]):
	# Call each scheme handler with the appropriate URIs
	if scheme == "file":
	part_names = [x[1] for x in groups]
	for cube in iris.io.load_files(part_names, callback, constraints):
	yield cube
	elif scheme in ["http", "https"]:
	urls = [":".join(x) for x in groups]
	for cube in iris.io.load_http(urls, callback):
	yield cube
	elif scheme == "data":
	data_objects = [x[1] for x in groups]
	for cube in iris.io.load_data_objects(data_objects, callback):
	yield cube
	else:
	raise ValueError("Iris cannot handle the URI scheme: %s" % scheme)

iris/lib/iris/fileformats/netcdf/ugrid_load.py

Lines 145 to 187 in 3432ca1

	if isinstance(uris, str):
	uris = [uris]
	# Group collections of uris by their iris handler
	# Create list of tuples relating schemes to part names.
	uri_tuples = sorted(decode_uri(uri) for uri in uris)
	valid_sources = []
	for scheme, groups in groupby(uri_tuples, key=lambda x: x[0]):
	# Call each scheme handler with the appropriate URIs
	if scheme == "file":
	filenames = [x[1] for x in groups]
	sources = expand_filespecs(filenames)
	elif scheme in ["http", "https"]:
	sources = [":".join(x) for x in groups]
	else:
	message = f"Iris cannot handle the URI scheme: {scheme}"
	raise ValueError(message)
	for source in sources:
	if scheme == "file":
	with open(source, "rb") as fh:
	handling_format_spec = FORMAT_AGENT.get_spec(Path(source).name, fh)
	else:
	handling_format_spec = FORMAT_AGENT.get_spec(source, None)
	if handling_format_spec.handler == nc_loader.load_cubes:
	valid_sources.append(source)
	else:
	message = f"Ignoring non-NetCDF file: {source}"
	logger.info(msg=message, extra=dict(cls=None))
	result = {}
	for source in valid_sources:
	with CFReader(source) as cf_reader:
	meshes_dict = _meshes_from_cf(cf_reader)
	meshes = list(meshes_dict.values())
	if var_name is not None:
	meshes = list(filter(lambda m: m.var_name == var_name, meshes))
	if meshes:
	result[source] = meshes
	return result