eCAL core v5 compatibility modus (part 1)

[KerstinKeller]

We want to introduce an eCAL 5 compatibility modus, which will make it easier to migrate to eCAL 6.

This PR is the first step for this.
There are now two targets, ecal_core and ecal_core_v5.
They differentiate on how they define the eCAL namespaces:

ecal_core:

namespace eCAL
{
namespace v5
{
  // deprecated old function
  void old_function();
}
inline namesapce v6
{
  void new_function();
}
}

and

ecal_core_v5:

namespace eCAL
{
inline namespace v5
{
  // deprecated old function
  void old_function();
}
namesapce v6
{
  void new_function();
}
}

In theory, when users migrate to eCAL 6, and enounter deleted functions, they can first use the compatibility mode.
Later they can switch back to core.
We will take the liberty to remove core_v5 during the lifetime of eCAL 6 (e.g. API stability is promised only for the core Target and v6 namespace functions.

Also, the eCAL will use the namespace macros:
ECAL_CORE_NAMESPACE_V5 and ECAL_CORE_NAMESPACE_V6 for opening the namespaces.

v5 files / implementations have been moved to v5 include / src folders to allow easier cleanup at a later stage.

[github-actions]

clang-tidy made some suggestions

[github-actions]

warning: declaration 'CServiceClientImpl' is never referenced, but a declaration with the same name found in another namespace 'eCAL::v6' [bugprone-forward-declaration-namespace]

  class CServiceClientImpl;
        ^

Additional context

ecal/core/include/ecal/ecal_client_instance.h:39: a declaration of 'CServiceClientImpl' is found here

    class CServiceClientImpl;
          ^

[github-actions]

warning: no definition found for 'CServiceClientImpl', but a definition with the same name 'CServiceClientImpl' found in another namespace 'eCAL::v6' [bugprone-forward-declaration-namespace]

  class CServiceClientImpl;
        ^

Additional context

ecal/core/src/service/ecal_service_client_impl.h:46: a definition of 'CServiceClientImpl' is found here

    class CServiceClientImpl : public std::enable_shared_from_this<CServiceClientImpl>
          ^

[github-actions]

warning: the const qualified parameter 'callback_' is copied for each invocation; consider making it a reference [performance-unnecessary-value-param]

ecal/core/src/pubsub/ecal_publisher_impl.h:89:

-     bool SetEventCallback(const v6::PubEventCallbackT callback_);
+     bool SetEventCallback(const v6::PubEventCallbackT& callback_);

Suggested change

	bool CPublisherImpl::SetEventCallback(const v6::PubEventCallbackT callback_)
	bool CPublisherImpl::SetEventCallback(const v6::PubEventCallbackT& callback_)

[github-actions]

warning: the const qualified parameter 'event_callback_' is copied for each invocation; consider making it a reference [performance-unnecessary-value-param]

ecal/core/include/ecal/ecal_subscriber.h:68:

-         CSubscriber(const std::string& topic_name_, const SDataTypeInformation& data_type_info_, const SubEventCallbackT event_callback_, const Subscriber::Configuration& config_ = GetSubscriberConfiguration());
+         CSubscriber(const std::string& topic_name_, const SDataTypeInformation& data_type_info_, const SubEventCallbackT& event_callback_, const Subscriber::Configuration& config_ = GetSubscriberConfiguration());

Suggested change

	CSubscriber::CSubscriber(const std::string & topic_name_, const SDataTypeInformation & data_type_info_, const SubEventCallbackT event_callback_, const Subscriber::Configuration & config_) :
	CSubscriber::CSubscriber(const std::string & topic_name_, const SDataTypeInformation & data_type_info_, const SubEventCallbackT& event_callback_, const Subscriber::Configuration & config_) :

[github-actions]

warning: the const qualified parameter 'callback_' is copied for each invocation; consider making it a reference [performance-unnecessary-value-param]

Suggested change

	bool CSubscriberImpl::SetEventIDCallback(const v6::SubEventCallbackT callback_)
	bool CSubscriberImpl::SetEventIDCallback(const v6::SubEventCallbackT& callback_)

ecal/core/src/pubsub/ecal_subscriber_impl.h:80:

-     bool SetEventIDCallback(const v6::SubEventCallbackT callback_);
+     bool SetEventIDCallback(const v6::SubEventCallbackT& callback_);

[github-actions]

warning: use of undeclared identifier 'System' [clang-diagnostic-error]

using namespace System::Collections::Generic;
                ^

[github-actions]

warning: 'ecal/msg/capnproto/helper.h' file not found [clang-diagnostic-error]

#include <ecal/msg/capnproto/helper.h>
         ^

[github-actions]

warning: 'ecal/ecal_deprecate.h' file not found [clang-diagnostic-error]

#include <ecal/ecal_deprecate.h>
         ^

[github-actions]

warning: 'ecal/ecal_deprecate.h' file not found [clang-diagnostic-error]

#include <ecal/ecal_deprecate.h>
         ^

[github-actions]

warning: 'ecal/v5/ecal_server.h' file not found [clang-diagnostic-error]

#include <ecal/v5/ecal_server.h>
         ^

[rex-schilasky]

THANK YOU!