+++ /dev/null
-"""Generic (shallow and deep) copying operations.
-
-Interface summary:
-
- import copy
-
- 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
-class instances).
-
-- A shallow copy constructs a new compound object and then (to the
- extent possible) inserts *the same objects* into it that the
- original contains.
-
-- 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
- copies
-
-Python's deep copy operation avoids these problems by:
-
- a) keeping a table of objects already copied during the current
- copying pass
-
- b) letting user-defined classes override the copying operation or the
- set of components copied
-
-This version does not copy types like module, class, function, method,
-nor stack trace, stack frame, nor file, socket, window, nor array, nor
-any similar types.
-
-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.
-"""
-
-import types
-import weakref
-from copyreg import dispatch_table
-
-class Error(Exception):
- pass
-error = Error # backward compatibility
-
-try:
- from org.python.core import PyStringMap
-except ImportError:
- PyStringMap = None
-
-__all__ = ["Error", "copy", "deepcopy"]
-
-def copy(x):
- """Shallow copy operation on arbitrary Python objects.
-
- See the module's __doc__ string for more info.
- """
-
- cls = type(x)
-
- copier = _copy_dispatch.get(cls)
- if copier:
- return copier(x)
-
- try:
- issc = issubclass(cls, type)
- except TypeError: # cls is not a class
- issc = False
- if issc:
- # treat it as a regular class:
- return _copy_immutable(x)
-
- copier = getattr(cls, "__copy__", None)
- if copier:
- return copier(x)
-
- reductor = dispatch_table.get(cls)
- if reductor:
- rv = reductor(x)
- else:
- reductor = getattr(x, "__reduce_ex__", None)
- if reductor:
- rv = reductor(4)
- else:
- reductor = getattr(x, "__reduce__", None)
- if reductor:
- rv = reductor()
- else:
- raise Error("un(shallow)copyable object of type %s" % cls)
-
- if isinstance(rv, str):
- return x
- return _reconstruct(x, None, *rv)
-
-
-_copy_dispatch = d = {}
-
-def _copy_immutable(x):
- return x
-for t in (type(None), int, float, bool, complex, str, tuple,
- bytes, frozenset, type, range, slice,
- types.BuiltinFunctionType, type(Ellipsis), type(NotImplemented),
- types.FunctionType, weakref.ref):
- d[t] = _copy_immutable
-t = getattr(types, "CodeType", None)
-if t is not None:
- d[t] = _copy_immutable
-
-d[list] = list.copy
-d[dict] = dict.copy
-d[set] = set.copy
-d[bytearray] = bytearray.copy
-
-if PyStringMap is not None:
- d[PyStringMap] = PyStringMap.copy
-
-del d, t
-
-def deepcopy(x, memo=None, _nil=[]):
- """Deep copy operation on arbitrary Python objects.
-
- See the module's __doc__ string for more info.
- """
-
- if memo is None:
- memo = {}
-
- d = id(x)
- y = memo.get(d, _nil)
- if y is not _nil:
- return y
-
- cls = type(x)
-
- copier = _deepcopy_dispatch.get(cls)
- if copier:
- y = copier(x, memo)
- else:
- try:
- issc = issubclass(cls, type)
- except TypeError: # cls is not a class (old Boost; see SF #502085)
- issc = 0
- if issc:
- y = _deepcopy_atomic(x, memo)
- else:
- copier = getattr(x, "__deepcopy__", None)
- if copier:
- y = copier(memo)
- else:
- reductor = dispatch_table.get(cls)
- if reductor:
- rv = reductor(x)
- else:
- reductor = getattr(x, "__reduce_ex__", None)
- if reductor:
- rv = reductor(4)
- else:
- reductor = getattr(x, "__reduce__", None)
- if reductor:
- rv = reductor()
- else:
- raise Error(
- "un(deep)copyable object of type %s" % cls)
- if isinstance(rv, str):
- y = x
- else:
- y = _reconstruct(x, memo, *rv)
-
- # If is its own copy, don't memoize.
- if y is not x:
- memo[d] = y
- _keep_alive(x, memo) # Make sure x lives at least as long as d
- return y
-
-_deepcopy_dispatch = d = {}
-
-def _deepcopy_atomic(x, memo):
- return x
-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
-try:
- d[types.CodeType] = _deepcopy_atomic
-except AttributeError:
- pass
-d[type] = _deepcopy_atomic
-d[types.BuiltinFunctionType] = _deepcopy_atomic
-d[types.FunctionType] = _deepcopy_atomic
-d[weakref.ref] = _deepcopy_atomic
-
-def _deepcopy_list(x, memo, deepcopy=deepcopy):
- y = []
- memo[id(x)] = y
- append = y.append
- for a in x:
- append(deepcopy(a, memo))
- return y
-d[list] = _deepcopy_list
-
-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.
- try:
- return memo[id(x)]
- except KeyError:
- pass
- for k, j in zip(x, y):
- if k is not j:
- y = tuple(y)
- break
- else:
- y = x
- return y
-d[tuple] = _deepcopy_tuple
-
-def _deepcopy_dict(x, memo, deepcopy=deepcopy):
- y = {}
- memo[id(x)] = y
- for key, value in x.items():
- y[deepcopy(key, memo)] = deepcopy(value, memo)
- return y
-d[dict] = _deepcopy_dict
-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
-
-del d
-
-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
- the memo itself...
- """
- try:
- memo[id(memo)].append(x)
- except KeyError:
- # aha, this is the first one :-)
- memo[id(memo)]=[x]
-
-def _reconstruct(x, memo, func, args,
- state=None, listiter=None, dictiter=None,
- deepcopy=deepcopy):
- deep = memo is not None
- if deep and args:
- args = (deepcopy(arg, memo) for arg in args)
- y = func(*args)
- if deep:
- memo[id(x)] = y
-
- if state is not None:
- if deep:
- state = deepcopy(state, memo)
- if hasattr(y, '__setstate__'):
- y.__setstate__(state)
- else:
- if isinstance(state, tuple) and len(state) == 2:
- state, slotstate = state
- else:
- slotstate = None
- if state is not None:
- y.__dict__.update(state)
- if slotstate is not None:
- for key, value in slotstate.items():
- setattr(y, key, value)
-
- if listiter is not None:
- if deep:
- for item in listiter:
- item = deepcopy(item, memo)
- y.append(item)
- else:
- for item in listiter:
- y.append(item)
- if dictiter is not None:
- if deep:
- for key, value in dictiter:
- key = deepcopy(key, memo)
- value = deepcopy(value, memo)
- y[key] = value
- else:
- for key, value in dictiter:
- y[key] = value
- return y
-
-del types, weakref, PyStringMap
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