Enhanced API to access Registration information

[KerstinKeller]

Context

We currently have different Utils function to receive information about the eCAL System.
E.g. Publishers / Subscribers, Clients / Servers and their attributes.

We need to improve this API to decrease system load in case of many entities.

Proposal

Idea for an API (to be reiterated):

struct EntityId;
enum class Type
{
  Publisher;
  Subscriber;
  Client;
  Service;
  Process;
}

std::vector<EntityId> Utils::GetEntities();

std::string GetTopicName(EntityId id);
std::vector<EntityId> Utils::GetEntityByName(std::string topic_name);
Type                  Utils::GetEntityType(EntityId id);
SDataTypeInformation  Utils::GetEntityDatatypeInformation(EntityId id);

using EntityCallback = std::function<void(const EntityId& id, ....);

Key Utils::AddEntityCallback(const EntityCallback& callback); 
void Utils::RemoveEntityCallback(const Key& key); 

bool IsPublisher(EntityId id);


struct SubscriberState
{
  EntityId id;
  State    state;
}
class Publisher
{
bool IsSubscribed();
// int GetSubscriberCount();
std::vector<SubscriberState> GetSubscribers();
}

Tasks and updates

No response