src/Mod/Part/BOPTools/Utils.py

# SPDX-License-Identifier: LGPL-2.1-or-later

# /***************************************************************************
# *   Copyright (c) 2016 Victor Titov (DeepSOIC) <vv.titov@gmail.com>       *
# *                                                                         *
# *   This file is part of the FreeCAD CAx development system.              *
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__title__ = "BOPTools.Utils module"
__author__ = "DeepSOIC"
__url__ = "https://www.freecad.org"
__doc__ = "Utility code, used by various modules of BOPTools."


class HashableShape(object):
    "Decorator for Part.Shape, that can be used as key in dicts. Based on isSame method."

    def __init__(self, shape):
        self.Shape = shape
        self.hash = shape.hashCode()

    def __eq__(self, other):
        return self.Shape.isSame(other.Shape)

    def __hash__(self):
        return self.hash


class HashableShape_Deep(object):
    """Similar to HashableShape, except that the things the shape is composed of are compared.

    Example:
        >>> wire2 = Part.Wire(wire1.childShapes())
        >>> wire2.isSame(wire1)
        False # <--- the wire2 is a new wire, although made of edges of wire1
        >>> HashableShape_Deep(wire2) == HashableShape_Deep(wire1)
        True # <--- made of same set of elements
    """

    def __init__(self, shape):
        self.Shape = shape
        self.hash = 0
        for el in shape.childShapes():
            self.hash = self.hash ^ el.hashCode()

    def __eq__(self, other):
        # avoiding extensive comparison for now. Just doing a few extra tests should reduce the already-low chances of false-positives
        if self.hash == other.hash:
            if len(self.Shape.childShapes()) == len(other.Shape.childShapes()):
                if self.Shape.ShapeType == other.Shape.ShapeType:
                    return True
        return False

    def __hash__(self):
        return self.hash


def compoundLeaves(shape_or_compound):
    """compoundLeaves(shape_or_compound): extracts all non-compound shapes from a nested compound.
    Note: shape_or_compound may be a non-compound; then, it is the only thing in the
    returned list."""

    if shape_or_compound.ShapeType == "Compound":
        leaves = []
        for child in shape_or_compound.childShapes():
            leaves.extend(compoundLeaves(child))
        return leaves
    else:
        return [shape_or_compound]


def upgradeToAggregateIfNeeded(list_of_shapes, types=None):
    """upgradeToAggregateIfNeeded(list_of_shapes, types = None): upgrades non-aggregate type
    shapes to aggregate-type shapes if the list has a mix of aggregate and non-aggregate
    type shapes. Returns the new list. Recursively traverses into compounds.

    aggregate shape types are Wire, Shell, CompSolid
    non-aggregate shape types are Vertex, Edge, Face, Solid
    Compounds are something special: they are recursively traversed to upgrade the
    contained shapes.

    Examples:
    list_of_shapes contains only faces -> nothing happens
    list_of_shapes contains faces and shells -> faces are converted to shells

    'types' argument is needed for recursive traversal. Do not supply."""

    import Part

    if types is None:
        types = set()
    for shape in list_of_shapes:
        types.add(shape.ShapeType)
        subshapes = compoundLeaves(shape)
        for subshape in subshapes:
            types.add(subshape.ShapeType)
    if "Wire" in types:
        list_of_shapes = [
            (Part.Wire([shape]) if shape.ShapeType == "Edge" else shape) for shape in list_of_shapes
        ]
    if "Shell" in types:
        list_of_shapes = [
            (Part.makeShell([shape]) if shape.ShapeType == "Face" else shape)
            for shape in list_of_shapes
        ]
    if "CompSolid" in types:
        list_of_shapes = [
            (Part.CompSolid([shape]) if shape.ShapeType == "Solid" else shape)
            for shape in list_of_shapes
        ]
    if "Compound" in types:
        list_of_shapes = [
            (
                Part.makeCompound(upgradeToAggregateIfNeeded(shape.childShapes(), types))
                if shape.ShapeType == "Compound"
                else shape
            )
            for shape in list_of_shapes
        ]
    return list_of_shapes


# adapted from http://stackoverflow.com/a/3603824/6285007
class FrozenClass(object):
    """FrozenClass: prevents adding new attributes to class outside of __init__"""

    __isfrozen = False

    def __setattr__(self, key, value):
        if self.__isfrozen and not hasattr(self, key):
            raise TypeError(
                "{cls} has no attribute {attr}".format(cls=self.__class__.__name__, attr=key)
            )
        object.__setattr__(self, key, value)

    def _freeze(self):
        self.__isfrozen = True

    def _unfreeze(self):
        self.__isfrozen = False