Fix #180

src/ifcopenshell-python/ifcopenshell/file.py

@@ -28,11 +28,11 @@ class file(object):
         self.wrapped_data = f or ifcopenshell_wrapper.file()
     def create_entity(self,type,*args,**kwargs):
         e = entity_instance(type)
+        self.wrapped_data.add(e.wrapped_data)
+        e.wrapped_data.this.disown()
         attrs = list(enumerate(args)) + \
             [(e.wrapped_data.get_argument_index(name), arg) for name, arg in kwargs.items()]
         for idx, arg in attrs: e[idx] = arg
-        self.wrapped_data.add(e.wrapped_data)
-        e.wrapped_data.this.disown()
         return e
     def __getattr__(self, attr):
         if attr[0:6] == 'create': return functools.partial(self.create_entity,attr[6:])

src/ifcparse/IfcFile.h

@@ -55,7 +55,7 @@ private:
 	IfcSpfHeader _header;
 
 	void setDefaultHeaderValues();
-	void register_inverse(unsigned, Token);
+
 public:
 	IfcParse::IfcSpfLexer* tokens;
 	IfcParse::IfcSpfStream* stream;
@@ -130,6 +130,10 @@ public:
 
 	void load(const IfcEntityInstanceData&);
 	void load(unsigned entity_instance_name, std::vector<Argument*>& attributes);
+
+	void register_inverse(unsigned, Token);
+	void register_inverse(unsigned, IfcUtil::IfcBaseClass*);
+	void unregister_inverse(unsigned, IfcUtil::IfcBaseClass*);
 };
 
 }

src/ifcparse/IfcParse.cpp

@@ -915,6 +915,20 @@ void IfcParse::IfcFile::register_inverse(unsigned id_from, Token t) {
 	byref[t.value_int].push_back(id_from);
 }
 
+void IfcParse::IfcFile::register_inverse(unsigned id_from, IfcUtil::IfcBaseClass* inst) {
+	byref[inst->entity->id()].push_back(id_from);
+}
+
+void IfcParse::IfcFile::unregister_inverse(unsigned id_from, IfcUtil::IfcBaseClass* inst) {
+	std::vector<unsigned int>& ids = byref[inst->entity->id()];
+	std::vector<unsigned int>::const_iterator it = std::find(ids.begin(), ids.end(), id_from);
+	if (it == ids.end()) {
+		throw IfcParse::IfcException("Instance not found among inverses");
+	} else {
+		ids.erase(it);
+	}
+}
+
 //
 // Returns a string representation of the entity
 // Note that this initializes the entity if it is not initialized
@@ -1008,6 +1022,97 @@ Argument* IfcEntityInstanceData::getArgument(unsigned int i) const {
 	}
 }
 
+class unregister_inverse_visitor {
+private:
+	IfcFile& file_;
+	const IfcEntityInstanceData& data_;
+
+public:
+	unregister_inverse_visitor(IfcFile& file, const IfcEntityInstanceData& data)
+		: file_(file), data_(data)
+	{}
+
+	void operator()(IfcUtil::IfcBaseClass* inst) {
+		file_.unregister_inverse(data_.id(), inst);
+	}
+};
+
+class register_inverse_visitor {
+private:
+	IfcFile& file_;
+	const IfcEntityInstanceData& data_;
+
+public:
+	register_inverse_visitor(IfcFile& file, const IfcEntityInstanceData& data)
+		: file_(file), data_(data)
+	{}
+
+	void operator()(IfcUtil::IfcBaseClass* inst) {
+		file_.register_inverse(data_.id(), inst);
+	}
+};
+
+class add_to_instance_list_visitor {
+private:
+	IfcEntityList::ptr& list_;
+
+public:
+	add_to_instance_list_visitor(IfcEntityList::ptr& list)
+		: list_(list)
+	{}
+
+	void operator()(IfcUtil::IfcBaseClass* inst) {
+		list_->push(inst);
+	}
+};
+
+class apply_individual_instance_visitor {
+private:
+	Argument* attribute_;
+	IfcEntityInstanceData* data_;
+
+	template <typename T>
+	void apply_attribute_(T& t, Argument* attr) const {
+		if (attr->type() == IfcUtil::Argument_ENTITY_INSTANCE) {
+			IfcUtil::IfcBaseClass* inst = *attr;
+			t(inst);
+		} else if (attr->type() == IfcUtil::Argument_AGGREGATE_OF_ENTITY_INSTANCE) {
+			IfcEntityList::ptr entity_list_attribute = *attr;
+			for (IfcEntityList::it it = entity_list_attribute->begin(); it != entity_list_attribute->end(); ++it) {
+				t(*it);
+			}
+		} else if (attr->type() == IfcUtil::Argument_AGGREGATE_OF_AGGREGATE_OF_ENTITY_INSTANCE) {
+			IfcEntityListList::ptr entity_list_attribute = *attr;
+			for (IfcEntityListList::outer_it it = entity_list_attribute->begin(); it != entity_list_attribute->end(); ++it) {
+				for (IfcEntityListList::inner_it jt = it->begin(); jt != it->end(); ++jt) {
+					t(*jt);
+				}
+			}
+		}
+	};
+public:
+	apply_individual_instance_visitor(Argument* attribute)
+		: attribute_(attribute), data_(0)
+	{}
+
+	apply_individual_instance_visitor(IfcEntityInstanceData* data)
+		: attribute_(0), data_(data)
+	{}
+
+	template <typename T>
+	void apply(T& t) const {
+		if (attribute_) {
+			apply_attribute_(t, attribute_);
+		} else {
+			for (unsigned i = 0; i < data_->getArgumentCount(); ++i) {
+				Argument* attr = data_->getArgument(i);
+				apply_attribute_(t, attr);
+			}
+		}
+	};
+
+};
+
 void IfcEntityInstanceData::setArgument(unsigned int i, Argument* a, IfcUtil::ArgumentType attr_type) {
 	if (!initialized_) {
 		load();
@@ -1017,10 +1122,6 @@ void IfcEntityInstanceData::setArgument(unsigned int i, Argument* a, IfcUtil::Ar
 		attributes_.push_back(new NullArgument());
 	}
 
-	if (i < attributes_.size()) {
-		delete attributes_[i];
-	}
-	
 	if (attr_type == IfcUtil::Argument_UNKNOWN) {
 		attr_type = a->type();
 	}
@@ -1117,6 +1218,20 @@ void IfcEntityInstanceData::setArgument(unsigned int i, Argument* a, IfcUtil::Ar
 		break;
 	}
 
+	if (i < attributes_.size()) {
+		Argument* current_attribute = attributes_[i];
+		if (this->file) {
+			unregister_inverse_visitor visitor(*this->file, *this);
+			apply_individual_instance_visitor(current_attribute).apply(visitor);
+		}
+		delete attributes_[i];
+	}
+
+	if (this->file) {
+		register_inverse_visitor visitor(*this->file, *this);
+		apply_individual_instance_visitor(copy).apply(visitor);
+	}	
+
 	if (i < attributes_.size()) {
 		attributes_[i] = copy;
 	} else {
@@ -1271,25 +1386,8 @@ void traverse_(IfcUtil::IfcBaseClass* instance, std::set<IfcUtil::IfcBaseClass*>
 
 	if (level >= max_level && max_level > 0) return;
 
-	for (unsigned i = 0; i < instance->getArgumentCount(); ++i) {
-		Argument* arg = instance->getArgument(i);
-
-		if (arg->type() == IfcUtil::Argument_ENTITY_INSTANCE) {
-			traverse_(*arg, visited, list, level + 1, max_level);
-		} else if (arg->type() == IfcUtil::Argument_AGGREGATE_OF_ENTITY_INSTANCE) {
-			IfcEntityList::ptr entity_list_attribute = *arg;
-			for (IfcEntityList::it it = entity_list_attribute->begin(); it != entity_list_attribute->end(); ++it) {
-				traverse_(*it, visited, list, level + 1, max_level);
-			}
-		} else if (arg->type() == IfcUtil::Argument_AGGREGATE_OF_AGGREGATE_OF_ENTITY_INSTANCE) {
-			IfcEntityListList::ptr entity_list_attribute = *arg;
-			for (IfcEntityListList::outer_it it = entity_list_attribute->begin(); it != entity_list_attribute->end(); ++it) {
-				for (IfcEntityListList::inner_it jt = it->begin(); jt != it->end(); ++jt) {
-					traverse_(*jt, visited, list, level + 1, max_level);
-				}
-			}
-		}
-	}
+	add_to_instance_list_visitor visit(list);
+	apply_individual_instance_visitor(instance->entity).apply(visit);
 }
 
 IfcEntityList::ptr IfcParse::traverse(IfcUtil::IfcBaseClass* instance, int max_level) {

test/tests.py

@@ -52,6 +52,16 @@ f[22].MiddleNames = 'John', 'Matthew'
 assert "('John','Matthew')" in str(f[22])
 assert ("Id", "123") in list(f[22].get_info().items())
 
+# Assignment of instances and implications on inverse attributes
+assert f[288].ConnectedTo[0].RelatingElement == f[288]
+num_connections_1 = len(f[340].ConnectedTo + f[340].ConnectedFrom)
+f[288].ConnectedTo[0].RelatingElement = f[340]
+num_connections_2 = len(f[340].ConnectedTo + f[340].ConnectedFrom)
+assert num_connections_2 == num_connections_1 + 1
+assert f[288].ConnectedTo == ()
+rel = f.createIfcRelConnectsPathElements(RelatingElement=f[288])
+assert f[288].ConnectedTo == (rel,)
+
 # Some operations on ifcopenshell.guid
 assert len(ifcopenshell.guid.compress(uuid.uuid1().hex)) == 22