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

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

@@ -0,0 +1,36 @@
+class Data:
+    products = {}
+    representations = {}
+
+    @classmethod
+    def purge(cls):
+        cls.products = {}
+        cls.representations = {}
+
+    @classmethod
+    def load(cls, file, product_id):
+        if not file:
+            return
+        cls.products[product_id] = []
+        product = file.by_id(product_id)
+        representations = []
+        if product.is_a("IfcProduct"):
+            if product.Representation:
+                representations = product.Representation.Representations
+            else:
+                representations = []
+        elif product.is_a("IfcTypeProduct"):
+            representations = [rm.MappedRepresentation for rm in product.RepresentationMaps or []]
+        for representation in representations:
+            c = representation.ContextOfItems
+            rep_id = int(representation.id())
+            cls.representations[rep_id] = {
+                "RepresentationIdentifier": representation.RepresentationIdentifier,
+                "RepresentationType": representation.RepresentationType,
+                "ContextOfItems": {
+                    "ContextType": c.ContextType,
+                    "ContextIdentifier": c.ContextIdentifier,
+                    "TargetView": c.TargetView if c.is_a("IfcGeometricRepresentationSubContext") else "",
+                }
+            }
+            cls.products[product_id].append(rep_id)