// defineFullInheritance copies any inherited members over to types, as well as type checking
// for inheritance cycles.
func (g *TypeGraph) defineFullInheritance(modifier compilergraph.GraphLayerModifier) {
buildInheritance := func(key interface{}, value interface{}) bool {
typeDecl := value.(TGTypeDecl)
g.buildInheritedMembership(typeDecl, NodePredicateMember, modifier)
g.buildInheritedMembership(typeDecl, NodePredicateTypeOperator, modifier)
return true
}
// Enqueue the full set of classes with dependencies on any parent types.
workqueue := compilerutil.Queue()
for _, typeDecl := range g.TypeDecls() {
if typeDecl.TypeKind() != ClassType {
continue
}
// Build a set of dependencies for this type.
var dependencies = make([]interface{}, 0)
for _, inheritsRef := range typeDecl.ParentTypes() {
dependencies = append(dependencies, inheritsRef.ReferredType())
}
workqueue.Enqueue(typeDecl, typeDecl, buildInheritance, dependencies...)
}
// Run the queue to construct the full inheritance.
result := workqueue.Run()
if result.HasCycle {
// TODO(jschorr): If there are two cycles, this will conflate them. We should do actual
// checking here.
var types = make([]string, len(result.Cycle))
for index, key := range result.Cycle {
decl := key.(TGTypeDecl)
types[index] = decl.Name()
}
typeNode := result.Cycle[0].(TGTypeDecl).GraphNode
g.decorateWithError(modifier.Modify(typeNode), "A cycle was detected in the inheritance of types: %v", types)
}
}
// buildInheritedMembership copies any applicable type members from the inherited type references to the given type.
func (t *TypeGraph) buildInheritedMembership(typeDecl TGTypeDecl, childPredicate compilergraph.Predicate, modifier compilergraph.GraphLayerModifier) {
// Build a map of all the existing names.
names := map[string]bool{}
it := typeDecl.GraphNode.StartQuery().
Out(childPredicate).
BuildNodeIterator(NodePredicateMemberName)
for it.Next() {
names[it.GetPredicate(NodePredicateMemberName).String()] = true
}
// Add members defined on the type's inheritance, skipping those already defined.
typeNode := typeDecl.GraphNode
for _, inherit := range typeDecl.ParentTypes() {
parentType := inherit.ReferredType()
pit := parentType.StartQuery().
Out(childPredicate).
BuildNodeIterator(NodePredicateMemberName)
for pit.Next() {
// Skip this member if already defined.
name := pit.GetPredicate(NodePredicateMemberName).String()
if _, exists := names[name]; exists {
// Ensure that the parent member is not a required field. If so, then we cannot
// shadow the field.
parentMember := TGMember{pit.Node(), t}
if parentMember.IsRequiredField() {
t.decorateWithError(modifier.Modify(typeDecl.GraphNode),
"%v %v cannot compose %v %v as it shadows %v '%v' which requires initialization",
typeDecl.Title(),
typeDecl.Name(),
parentType.Title(),
parentType.Name(),
parentMember.Title(),
parentMember.Name())
}
continue
}
// Mark the name as added.
names[name] = true
// Create a new node of the same kind and copy over any predicates except the type.
parentMemberNode := pit.Node()
memberNode := parentMemberNode.CloneExcept(modifier, NodePredicateMemberType)
memberNode.Connect(NodePredicateMemberBaseMember, parentMemberNode)
memberNode.DecorateWithTagged(NodePredicateMemberBaseSource, inherit)
modifier.Modify(typeNode).Connect(childPredicate, memberNode)
// If the node is an operator, nothing more to do.
if memberNode.Kind == NodeTypeOperator {
continue
}
parentMemberType := parentMemberNode.GetTagged(NodePredicateMemberType, t.AnyTypeReference()).(TypeReference)
// If the parent type has generics, then replace the generics in the member type with those
// specified in the inheritance type reference.
if _, ok := parentType.GraphNode.TryGetNode(NodePredicateTypeGeneric); !ok {
// Parent type has no generics, so just decorate with the type directly.
memberNode.DecorateWithTagged(NodePredicateMemberType, parentMemberType)
continue
}
memberType := parentMemberType.TransformUnder(inherit)
memberNode.DecorateWithTagged(NodePredicateMemberType, memberType)
}
}
}