"""Generic (shallow and deep) copying operations.
x = copy.copy(y) # make a shallow copy of y
x = copy.deepcopy(y) # make a deep copy of y
For module specific errors, copy.Error is raised.
The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
- A shallow copy constructs a new compound object and then (to the
extent possible) inserts *the same objects* into it that the
- A deep copy constructs a new compound object and then, recursively,
inserts *copies* into it of the objects found in the original.
Two problems often exist with deep copy operations that don't exist
with shallow copy operations:
a) recursive objects (compound objects that, directly or indirectly,
contain a reference to themselves) may cause a recursive loop
b) because deep copy copies *everything* it may copy too much, e.g.
administrative data structures that should be shared even between
Python's deep copy operation avoids these problems by:
a) keeping a table of objects already copied during the current
b) letting user-defined classes override the copying operation or the
This version does not copy types like module, class, function, method,
nor stack trace, stack frame, nor file, socket, window, nor array, nor
Classes can use the same interfaces to control copying that they use
to control pickling: they can define methods called __getinitargs__(),
__getstate__() and __setstate__(). See the documentation for module
"pickle" for information on these methods.
from copyreg import dispatch_table
error = Error # backward compatibility
from org.python.core import PyStringMap
__all__ = ["Error", "copy", "deepcopy"]
"""Shallow copy operation on arbitrary Python objects.
See the module's __doc__ string for more info.
copier = _copy_dispatch.get(cls)
if issubclass(cls, type):
# treat it as a regular class:
return _copy_immutable(x)
copier = getattr(cls, "__copy__", None)
reductor = dispatch_table.get(cls)
reductor = getattr(x, "__reduce_ex__", None)
reductor = getattr(x, "__reduce__", None)
raise Error("un(shallow)copyable object of type %s" % cls)
return _reconstruct(x, None, *rv)
for t in (type(None), int, float, bool, complex, str, tuple,
bytes, frozenset, type, range, slice, property,
types.BuiltinFunctionType, type(Ellipsis), type(NotImplemented),
types.FunctionType, weakref.ref):
t = getattr(types, "CodeType", None)
d[bytearray] = bytearray.copy
if PyStringMap is not None:
d[PyStringMap] = PyStringMap.copy
def deepcopy(x, memo=None, _nil=[]):
"""Deep copy operation on arbitrary Python objects.
See the module's __doc__ string for more info.
copier = _deepcopy_dispatch.get(cls)
if issubclass(cls, type):
y = _deepcopy_atomic(x, memo)
copier = getattr(x, "__deepcopy__", None)
reductor = dispatch_table.get(cls)
reductor = getattr(x, "__reduce_ex__", None)
reductor = getattr(x, "__reduce__", None)
"un(deep)copyable object of type %s" % cls)
y = _reconstruct(x, memo, *rv)
# If is its own copy, don't memoize.
_keep_alive(x, memo) # Make sure x lives at least as long as d
_deepcopy_dispatch = d = {}
def _deepcopy_atomic(x, memo):
d[type(None)] = _deepcopy_atomic
d[type(Ellipsis)] = _deepcopy_atomic
d[type(NotImplemented)] = _deepcopy_atomic
d[int] = _deepcopy_atomic
d[float] = _deepcopy_atomic
d[bool] = _deepcopy_atomic
d[complex] = _deepcopy_atomic
d[bytes] = _deepcopy_atomic
d[str] = _deepcopy_atomic
d[types.CodeType] = _deepcopy_atomic
d[type] = _deepcopy_atomic
d[types.BuiltinFunctionType] = _deepcopy_atomic
d[types.FunctionType] = _deepcopy_atomic
d[weakref.ref] = _deepcopy_atomic
d[property] = _deepcopy_atomic
def _deepcopy_list(x, memo, deepcopy=deepcopy):
append(deepcopy(a, memo))
def _deepcopy_tuple(x, memo, deepcopy=deepcopy):
y = [deepcopy(a, memo) for a in x]
# We're not going to put the tuple in the memo, but it's still important we
# check for it, in case the tuple contains recursive mutable structures.
d[tuple] = _deepcopy_tuple
def _deepcopy_dict(x, memo, deepcopy=deepcopy):
for key, value in x.items():
y[deepcopy(key, memo)] = deepcopy(value, memo)
if PyStringMap is not None:
d[PyStringMap] = _deepcopy_dict
def _deepcopy_method(x, memo): # Copy instance methods
return type(x)(x.__func__, deepcopy(x.__self__, memo))
d[types.MethodType] = _deepcopy_method
def _keep_alive(x, memo):
"""Keeps a reference to the object x in the memo.
Because we remember objects by their id, we have
to assure that possibly temporary objects are kept
alive by referencing them.
We store a reference at the id of the memo, which should
normally not be used unless someone tries to deepcopy
# aha, this is the first one :-)
def _reconstruct(x, memo, func, args,
state=None, listiter=None, dictiter=None,
args = (deepcopy(arg, memo) for arg in args)
state = deepcopy(state, memo)
if hasattr(y, '__setstate__'):
if isinstance(state, tuple) and len(state) == 2:
if slotstate is not None:
for key, value in slotstate.items():
item = deepcopy(item, memo)
for key, value in dictiter:
key = deepcopy(key, memo)
value = deepcopy(value, memo)
for key, value in dictiter:
del types, weakref, PyStringMap
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
