Draft: parent classes of all Draft objects

Add DraftObject and ViewProviderDraft to serve as
the parent classes of all Draft objects
and all Draft view providers.

Inside `Draft.py` we need to import
`_DraftObject` from `draftobjects.base`;
and `_ViewProviderDraft`, `_ViewProviderDraftAlt`,
and `_ViewProviderDraftPart` from `draftviewproviders.view_base`.
.


.


.


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src/Mod/Draft/draftobjects/base.py

@@ -0,0 +1,155 @@
+# ***************************************************************************
+# *   Copyright (c) 2009, 2010 Yorik van Havre <yorik@uncreated.net>        *
+# *   Copyright (c) 2009, 2010 Ken Cline <cline@frii.com>                   *
+# *   Copyright (c) 2019 Eliud Cabrera Castillo <e.cabrera-castillo@tum.de> *
+# *                                                                         *
+# *   This program is free software; you can redistribute it and/or modify  *
+# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
+# *   as published by the Free Software Foundation; either version 2 of     *
+# *   the License, or (at your option) any later version.                   *
+# *   for detail see the LICENCE text file.                                 *
+# *                                                                         *
+# *   This program is distributed in the hope that it will be useful,       *
+# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+# *   GNU Library General Public License for more details.                  *
+# *                                                                         *
+# *   You should have received a copy of the GNU Library General Public     *
+# *   License along with this program; if not, write to the Free Software   *
+# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
+# *   USA                                                                   *
+# *                                                                         *
+# ***************************************************************************
+"""This module provides the object code for the basic Draft object.
+"""
+## @package base
+# \ingroup DRAFT
+# \brief This module provides the object code for the basic Draft object.
+
+class DraftObject(object):
+    """The base class for Draft objects.
+
+    Parameters
+    ----------
+    obj : a base C++ object
+        The base object instantiated during creation,
+        which commonly may be of types `Part::Part2DObjectPython`,
+        `Part::FeaturePython`, or `App::FeaturePython`.
+
+            >>> obj = App.ActiveDocument.addObject('Part::Part2DObjectPython')
+            >>> DraftObject(obj)
+
+        This class instance is stored in the `Proxy` attribute
+        of the base object.
+        ::
+            obj.Proxy = self
+
+    tp : str, optional
+        It defaults to `'Unknown'`.
+        It indicates the type of this scripted object,
+        which will be assigned to the Proxy's `Type` attribute.
+
+        This is useful to distinguish different types of scripted objects
+        that may be derived from the same C++ class.
+
+    Attributes
+    ----------
+    Type : str
+        It indicates the type of scripted object.
+        Normally `Type = tp`.
+
+        All objects have a `TypeId` attribute, but this attribute
+        refers to the C++ class only. Using the `Type` attribute
+        allows distinguishing among various types of objects
+        derived from the same C++ class.
+
+            >>> print(A.TypeId, "->", A.Proxy.Type)
+            Part::Part2DObjectPython -> Wire
+            >>> print(B.TypeId, "->", B.Proxy.Type)
+            Part::Part2DObjectPython -> Circle
+
+    This class attribute is accessible through the `Proxy` object:
+    `obj.Proxy.Type`.
+    """
+    def __init__(self, obj, tp="Unknown"):
+        # This class is assigned to the Proxy attribute
+        if obj:
+            obj.Proxy = self
+        self.Type = tp
+
+    def __getstate__(self):
+        """Return a tuple of all serializable objects or None.
+
+        When saving the document this object gets stored
+        using Python's `json` module.
+
+        Override this method to define the serializable objects to return.
+
+        By default it returns the `Type` attribute.
+
+        Returns
+        -------
+        str
+            Returns the value of `Type`
+        """
+        return self.Type
+
+    def __setstate__(self, state):
+        """Set some internal properties for all restored objects.
+
+        When a document is restored this method is used to set some properties
+        for the objects stored with `json`.
+
+        Override this method to define the properties to change for the
+        restored serialized objects.
+
+        By default the `Type` was serialized, so `state` holds this value,
+        which is re-assigned to the `Type` attribute.
+        ::
+            self.Type = state
+
+        Parameters
+        ---------
+        state : state
+            A serialized object.
+        """
+        if state:
+            self.Type = state
+
+    def execute(self, obj):
+        """This method is run when the object is created or recomputed.
+
+        Override this method to produce effects when the object
+        is newly created, and whenever the document is recomputed.
+
+        By default it does nothing.
+
+        Paramaters
+        ----------
+        obj : the scripted object.
+            This commonly may be of types `Part::Part2DObjectPython`,
+            `Part::FeaturePython`, or `App::FeaturePython`.
+        """
+        pass
+
+    def onChanged(self, obj, prop):
+        """This method is run when a property is changed.
+
+        Override this method to handle the behavior
+        of the object depending on changes that occur to its properties.
+
+        By default it does nothing.
+
+        Paramaters
+        ----------
+        obj : the scripted object.
+            This commonly may be of types `Part::Part2DObjectPython`,
+            `Part::FeaturePython`, or `App::FeaturePython`.
+
+        prop : str
+            Name of the property that was modified.
+        """
+        pass
+
+
+_DraftObject = DraftObject