TypeRegistry

class TypeRegistry

Bases: MemoryBase

The TypeRegistry class maintains all the assigned TypeHandles in a given system. There should be only one TypeRegistry class during the lifetime of the application. It will be created on the local heap initially, and it should be migrated to shared memory as soon as shared memory becomes available.

Inheritance diagram

TypeRegistry(TypeRegistry const&) = default

TypeHandle find_type(std::string const &name) const: Looks for a previously-registered type of the given name. Returns its TypeHandle if it exists, or TypeHandle::none() if there is no such type.

TypeHandle find_type_by_id(int id) const: Looks for a previously-registered type with the given id number (as returned by TypeHandle::get_index()). Returns its TypeHandle if it exists, or TypeHandle::none() if there is no such type.

TypeHandle get_child_class(TypeHandle child, int index) const: Returns the nth child class of this type. The index should be in the range 0 <= index < get_num_child_classes().

std::string get_name(TypeHandle type, TypedObject *object) const

Returns the name of the indicated type.

The “object” pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

int get_num_child_classes(TypeHandle child, TypedObject *child_object) const

Returns the number of child classes that the indicated type is known to have. This may then be used to index into get_child_class().

The “object” pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

int get_num_parent_classes(TypeHandle child, TypedObject *child_object) const

Returns the number of parent classes that the indicated type is known to have. This may then be used to index into get_parent_class(). The result will be 0 if this class does not inherit from any other classes, 1 if normal, single inheritance is in effect, or greater than one if multiple inheritance is in effect.

The “object” pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

int get_num_root_classes(void): Returns the number of root classes–that is, classes that do not inherit from any other classes–known in the system.

int get_num_typehandles(void): Returns the total number of unique TypeHandles in the system.

TypeHandle get_parent_class(TypeHandle child, int index) const: Returns the nth parent class of this type. The index should be in the range 0 <= index < get_num_parent_classes().

TypeHandle get_parent_towards(TypeHandle child, TypeHandle base, TypedObject *child_object)

Returns the parent of the indicated child class that is in a direct line of inheritance to the indicated ancestor class. This is useful in the presence of multiple inheritance to try to determine what properties an unknown type may have.

The “object” pointer is an optional pointer to the TypedObject class that owns this TypeHandle. It is only used in case the TypeHandle is inadvertantly undefined.

TypeHandle get_root_class(int n): Returns the nth root class in the system. See get_num_root_classes().

TypeHandle get_typehandle(int n): Returns the nth TypeHandle in the system. See get_num_typehandles().

bool is_derived_from(TypeHandle child, TypeHandle base, TypedObject *child_object)

Returns true if the first type is derived from the second type, false otherwise.

The “child_object” pointer is an optional pointer to the TypedObject class that owns the child TypeHandle. It is only used in case the TypeHandle is inadvertently undefined.

This function definition follows the definitions for look_up() and freshen_derivations() just to maximize the chance the the compiler will be able to inline the above functions. Yeah, a compiler shouldn’t care, but there’s a big different between “shouldn’t” and “doesn’t”.

TypeRegistry *ptr(void)

ptr() returns the pointer to the global TypeRegistry object.

Returns the pointer to the global TypeRegistry object.

void record_alternate_name(TypeHandle type, std::string const &name): Indicates an alternate name for the same type. This is particularly useful when a type has changed names, since the type is stored in a Bam file by name; setting the original name as the alternate will allow the type to be correctly read from old Bam files.

void record_derivation(TypeHandle child, TypeHandle parent): Records that the type referenced by child inherits directly from the type referenced by parent. In the event of multiple inheritance, this should be called once for each parent class.

void record_python_type(TypeHandle type, PyObject *python_type): Records the given Python type pointer in the type registry for the benefit of interrogate, which expects this to contain a Dtool_PyTypedObject.

TypeHandle register_dynamic_type(std::string const &name): Registers a new type on-the-fly, presumably at runtime. A new TypeHandle is returned if the typename was not seen before; otherwise the same TypeHandle that was last used for this typename is returned.

static void reregister_types(void): Walks through the TypeRegistry tree and makes sure that each type that was previously registered is still registered. This seems to get broken in certain circumstances when compiled against libc5–it is as if the static initializer stomps on the _type_handle values of each class after they’ve been registered.

void write(std::ostream &out) const: Makes an attempt to format the entire TypeRegistry in a nice way that shows the derivation tree as intelligently as possible.