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+"""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 copy_reg 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)
+
+ 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(2)
+ else:
+ reductor = getattr(x, "__reduce__", None)
+ if reductor:
+ rv = reductor()
+ else:
+ raise Error("un(shallow)copyable object of type %s" % cls)
+
+ return _reconstruct(x, rv, 0)
+
+
+_copy_dispatch = d = {}
+
+def _copy_immutable(x):
+ return x
+for t in (type(None), int, long, float, bool, str, tuple,
+ frozenset, type, xrange, types.ClassType,
+ types.BuiltinFunctionType, type(Ellipsis),
+ types.FunctionType, weakref.ref):
+ d[t] = _copy_immutable
+for name in ("ComplexType", "UnicodeType", "CodeType"):
+ t = getattr(types, name, None)
+ if t is not None:
+ d[t] = _copy_immutable
+
+def _copy_with_constructor(x):
+ return type(x)(x)
+for t in (list, dict, set):
+ d[t] = _copy_with_constructor
+
+def _copy_with_copy_method(x):
+ return x.copy()
+if PyStringMap is not None:
+ d[PyStringMap] = _copy_with_copy_method
+
+def _copy_inst(x):
+ if hasattr(x, '__copy__'):
+ return x.__copy__()
+ if hasattr(x, '__getinitargs__'):
+ args = x.__getinitargs__()
+ y = x.__class__(*args)
+ else:
+ y = _EmptyClass()
+ y.__class__ = x.__class__
+ if hasattr(x, '__getstate__'):
+ state = x.__getstate__()
+ else:
+ state = x.__dict__
+ if hasattr(y, '__setstate__'):
+ y.__setstate__(state)
+ else:
+ y.__dict__.update(state)
+ return y
+d[types.InstanceType] = _copy_inst
+
+del d
+
+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(2)
+ else:
+ reductor = getattr(x, "__reduce__", None)
+ if reductor:
+ rv = reductor()
+ else:
+ raise Error(
+ "un(deep)copyable object of type %s" % cls)
+ y = _reconstruct(x, rv, 1, memo)
+
+ 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[int] = _deepcopy_atomic
+d[long] = _deepcopy_atomic
+d[float] = _deepcopy_atomic
+d[bool] = _deepcopy_atomic
+try:
+ d[complex] = _deepcopy_atomic
+except NameError:
+ pass
+d[str] = _deepcopy_atomic
+try:
+ d[unicode] = _deepcopy_atomic
+except NameError:
+ pass
+try:
+ d[types.CodeType] = _deepcopy_atomic
+except AttributeError:
+ pass
+d[type] = _deepcopy_atomic
+d[xrange] = _deepcopy_atomic
+d[types.ClassType] = _deepcopy_atomic
+d[types.BuiltinFunctionType] = _deepcopy_atomic
+d[types.FunctionType] = _deepcopy_atomic
+d[weakref.ref] = _deepcopy_atomic
+
+def _deepcopy_list(x, memo):
+ y = []
+ memo[id(x)] = y
+ for a in x:
+ y.append(deepcopy(a, memo))
+ return y
+d[list] = _deepcopy_list
+
+def _deepcopy_tuple(x, memo):
+ y = []
+ for a in x:
+ y.append(deepcopy(a, memo))
+ d = id(x)
+ try:
+ return memo[d]
+ except KeyError:
+ pass
+ for i in range(len(x)):
+ if x[i] is not y[i]:
+ y = tuple(y)
+ break
+ else:
+ y = x
+ memo[d] = y
+ return y
+d[tuple] = _deepcopy_tuple
+
+def _deepcopy_dict(x, memo):
+ y = {}
+ memo[id(x)] = y
+ for key, value in x.iteritems():
+ 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.im_func, deepcopy(x.im_self, memo), x.im_class)
+_deepcopy_dispatch[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
+ the memo itself...
+ """
+ try:
+ memo[id(memo)].append(x)
+ except KeyError:
+ # aha, this is the first one :-)
+ memo[id(memo)]=[x]
+
+def _deepcopy_inst(x, memo):
+ if hasattr(x, '__deepcopy__'):
+ return x.__deepcopy__(memo)
+ if hasattr(x, '__getinitargs__'):
+ args = x.__getinitargs__()
+ args = deepcopy(args, memo)
+ y = x.__class__(*args)
+ else:
+ y = _EmptyClass()
+ y.__class__ = x.__class__
+ memo[id(x)] = y
+ if hasattr(x, '__getstate__'):
+ state = x.__getstate__()
+ else:
+ state = x.__dict__
+ state = deepcopy(state, memo)
+ if hasattr(y, '__setstate__'):
+ y.__setstate__(state)
+ else:
+ y.__dict__.update(state)
+ return y
+d[types.InstanceType] = _deepcopy_inst
+
+def _reconstruct(x, info, deep, memo=None):
+ if isinstance(info, str):
+ return x
+ assert isinstance(info, tuple)
+ if memo is None:
+ memo = {}
+ n = len(info)
+ assert n in (2, 3, 4, 5)
+ callable, args = info[:2]
+ if n > 2:
+ state = info[2]
+ else:
+ state = {}
+ if n > 3:
+ listiter = info[3]
+ else:
+ listiter = None
+ if n > 4:
+ dictiter = info[4]
+ else:
+ dictiter = None
+ if deep:
+ args = deepcopy(args, memo)
+ y = callable(*args)
+ memo[id(x)] = y
+
+ if state:
+ 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.iteritems():
+ setattr(y, key, value)
+
+ if listiter is not None:
+ for item in listiter:
+ if deep:
+ item = deepcopy(item, memo)
+ y.append(item)
+ if dictiter is not None:
+ for key, value in dictiter:
+ if deep:
+ key = deepcopy(key, memo)
+ value = deepcopy(value, memo)
+ y[key] = value
+ return y
+
+del d
+
+del types
+
+# Helper for instance creation without calling __init__
+class _EmptyClass:
+ pass
+
+def _test():
+ l = [None, 1, 2L, 3.14, 'xyzzy', (1, 2L), [3.14, 'abc'],
+ {'abc': 'ABC'}, (), [], {}]
+ l1 = copy(l)
+ print l1==l
+ l1 = map(copy, l)
+ print l1==l
+ l1 = deepcopy(l)
+ print l1==l
+ class C:
+ def __init__(self, arg=None):
+ self.a = 1
+ self.arg = arg
+ if __name__ == '__main__':
+ import sys
+ file = sys.argv[0]
+ else:
+ file = __file__
+ self.fp = open(file)
+ self.fp.close()
+ def __getstate__(self):
+ return {'a': self.a, 'arg': self.arg}
+ def __setstate__(self, state):
+ for key, value in state.iteritems():
+ setattr(self, key, value)
+ def __deepcopy__(self, memo=None):
+ new = self.__class__(deepcopy(self.arg, memo))
+ new.a = self.a
+ return new
+ c = C('argument sketch')
+ l.append(c)
+ l2 = copy(l)
+ print l == l2
+ print l
+ print l2
+ l2 = deepcopy(l)
+ print l == l2
+ print l
+ print l2
+ l.append({l[1]: l, 'xyz': l[2]})
+ l3 = copy(l)
+ import repr
+ print map(repr.repr, l)
+ print map(repr.repr, l1)
+ print map(repr.repr, l2)
+ print map(repr.repr, l3)
+ l3 = deepcopy(l)
+ import repr
+ print map(repr.repr, l)
+ print map(repr.repr, l1)
+ print map(repr.repr, l2)
+ print map(repr.repr, l3)
+ class odict(dict):
+ def __init__(self, d = {}):
+ self.a = 99
+ dict.__init__(self, d)
+ def __setitem__(self, k, i):
+ dict.__setitem__(self, k, i)
+ self.a
+ o = odict({"A" : "B"})
+ x = deepcopy(o)
+ print(o, x)
+
+if __name__ == '__main__':
+ _test()