def _Promote(arg, klass):
"""Wrap an argument in an object of the specified class.
This is used to e.g.: promote numbers or strings to Images and arrays
to Collections.
Args:
arg: The object to promote.
klass: The expected type.
Returns:
The argument promoted if the class is recognized, otherwise the
original argument.
"""
if arg is None:
return arg
if klass == 'Image':
return Image(arg)
elif klass == 'Feature':
if isinstance(arg, Collection):
# TODO(user): Decide whether we want to leave this in. It can be
# quite dangerous on large collections.
return ApiFunction.call_(
'Feature', ApiFunction.call_('Collection.geometry', arg))
else:
return Feature(arg)
elif klass == 'Element':
if isinstance(arg, Element):
# Already an Element.
return arg
elif isinstance(arg, Geometry):
# Geometries get promoted to Features.
return Feature(arg)
elif isinstance(arg, ComputedObject):
# Try a cast.
return Element(arg.func, arg.args, arg.varName)
else:
# No way to convert.
raise EEException('Cannot convert %s to Element.' % arg)
elif klass == 'Geometry':
if isinstance(arg, Collection):
return ApiFunction.call_('Collection.geometry', arg)
else:
return Geometry(arg)
elif klass in ('FeatureCollection', 'Collection'):
# For now Collection is synonymous with FeatureCollection.
if isinstance(arg, Collection):
return arg
else:
return FeatureCollection(arg)
elif klass == 'ImageCollection':
return ImageCollection(arg)
elif klass == 'Filter':
return Filter(arg)
elif klass == 'Algorithm':
if isinstance(arg, basestring):
# An API function name.
return ApiFunction.lookup(arg)
elif callable(arg):
# A native function that needs to be wrapped.
args_count = len(inspect.getargspec(arg).args)
return CustomFunction.create(arg, 'Object',
['Object'] * args_count)
elif isinstance(arg, Encodable):
# An ee.Function or a computed function like the return value of
# Image.parseExpression().
return arg
else:
raise EEException('Argument is not a function: %s' % arg)
elif klass == 'Dictionary':
if isinstance(arg, dict):
return arg
else:
return Dictionary(arg)
elif klass == 'String':
if (types.isString(arg) or isinstance(arg, ComputedObject)
or isinstance(arg, String)):
return String(arg)
else:
return arg
elif klass == 'List':
return List(arg)
elif klass in ('Number', 'Float', 'Long', 'Integer', 'Short', 'Byte'):
return Number(arg)
elif klass in globals():
cls = globals()[klass]
ctor = ApiFunction.lookupInternal(klass)
# Handle dynamically created classes.
if isinstance(arg, cls):
# Return unchanged.
return arg
elif ctor:
# The client-side constructor will call the server-side constructor.
return cls(arg)
elif isinstance(arg, basestring):
if hasattr(cls, arg):
# arg is the name of a method in klass.
return getattr(cls, arg)()
else:
raise EEException('Unknown algorithm: %s.%s' % (klass, arg))
else:
# Client-side cast.
return cls(arg)
else:
return arg
