First attempt at ripping out agnostic code into ifcopenshell.api namespace. See #1399.

src/ifcopenshell-python/ifcopenshell/api/spatial/assign_container.py

@@ -0,0 +1,42 @@
+import ifcopenshell
+
+
+class Usecase:
+    def __init__(self, file, settings=None):
+        self.file = file
+        self.settings = {
+            "product": None,
+            "relating_structure": None,
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        contained_in_structure = self.settings["product"].ContainedInStructure
+        contains_elements = self.settings["relating_structure"].ContainsElements
+
+        if contains_elements and contained_in_structure and contained_in_structure[0] == contains_elements[0]:
+            return
+
+        if contained_in_structure:
+            related_elements = list(contained_in_structure[0].RelatedElements)
+            related_elements.remove(self.settings["product"])
+            if related_elements:
+                contained_in_structure[0].RelatedElements = related_elements
+            else:
+                self.file.remove(contained_in_structure[0])
+
+        if contains_elements:
+            related_elements = list(contains_elements[0].RelatedElements)
+            related_elements.append(self.settings["product"])
+            contains_elements[0].RelatedElements = related_elements
+        else:
+            contains_elements = self.file.create_entity(
+                "IfcRelContainedInSpatialStructure",
+                **{
+                    "GlobalId": ifcopenshell.guid.new(),
+                    # TODO "OwnerHistory": None
+                    "RelatedElements": [self.settings["product"]],
+                    "RelatingStructure": self.settings["relating_structure"],
+                }
+            )

src/ifcopenshell-python/ifcopenshell/api/spatial/data.py

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+class Data:
+    products = {}
+    spatial_elements = {}
+
+    @classmethod
+    def purge(cls):
+        cls.products = {}
+        cls.spatial_elements = {}
+
+    @classmethod
+    def load(cls, file, product_id=None):
+        if product_id:
+            return cls.load_product(file, product_id)
+        cls.load_spatial_elements(file)
+
+    @classmethod
+    def load_product(cls, file, product_id):
+        if not file:
+            return
+        product = file.by_id(product_id)
+        if not hasattr(product, "ContainedInStructure"):
+            cls.products[product_id] = None
+        elif product.ContainedInStructure:
+            structure = product.ContainedInStructure[0].RelatingStructure
+            cls.products[product_id] = {"type": structure.is_a(), "Name": structure.Name, "id": int(structure.id())}
+        else:
+            cls.products[product_id] = {"type": None, "Name": None, "id": None}
+
+    @classmethod
+    def load_spatial_elements(cls, file):
+        if not file:
+            return
+        cls.spatial_elements = {}
+        ifc_class = "IfcSpatialElement"
+        if file.schema == "IFC2X3":
+            ifc_class = "IfcSpatialStructureElement"
+        for element in file.by_type(ifc_class):
+            decomposes = None
+            if element.Decomposes:
+                decomposes = element.Decomposes[0].RelatingObject.id()
+            is_decomposed_by = []
+            if element.IsDecomposedBy:
+                for rel in element.IsDecomposedBy:
+                    is_decomposed_by.extend([e.id() for e in rel.RelatedObjects])
+            cls.spatial_elements[element.id()] = {
+                "Name": element.Name,
+                "LongName": element.LongName,
+                "Decomposes": decomposes,
+                "IsDecomposedBy": is_decomposed_by
+            }

src/ifcopenshell-python/ifcopenshell/api/spatial/remove_container.py

@@ -0,0 +1,20 @@
+import ifcopenshell
+
+
+class Usecase:
+    def __init__(self, file, settings=None):
+        self.file = file
+        self.settings = {"product": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        contained_in_structure = self.settings["product"].ContainedInStructure
+
+        if contained_in_structure:
+            related_elements = list(contained_in_structure[0].RelatedElements)
+            related_elements.remove(self.settings["product"])
+            if related_elements:
+                contained_in_structure[0].RelatedElements = related_elements
+            else:
+                self.file.remove(contained_in_structure)