Base class has protected destructor

[peskygnat]

We are investigating using javacpp and moving away from swig.

We have a base class that intentionally has a protected destructor.

 class Object_I {
        protected :
            inline virtual ~Object_I() = 0;
        };
        
       inline Object_I::~Object_I() {
        }

Inherited by many classes including the following:

 class Child_T : public Object_I {
        public :
            long time;
            };

results in the following error:

jnicommon.cpp: In function ‘void JavaCPP_common_00024Object_1I_deallocate(void*)’:
jnicommon.cpp:371:123: error: ‘virtual Object_I::~Object_I()’ is protected within this context
 static void JavaCPP_common_00024Object_1I_deallocate(void *p) { delete (Object_I*)p; }
                                                                                                                           ^
In file included from jnicommon.cpp:102:
Object_I.h:35:16: note: declared protected here
         inline Object_I::~Object_I() {

This is how swig decided to deal with the Object_I with its code generation:

public class Object_I {
  private long swigCPtr;
  protected boolean swigCMemOwn;

  public Object_I(long cPtr, boolean cMemoryOwn) {
    swigCMemOwn = cMemoryOwn;
    swigCPtr = cPtr;
  }

  public static long getCPtr(Object_I obj) {
    return (obj == null) ? 0 : obj.swigCPtr;
  }

   public synchronized void delete() {
    if (swigCPtr != 0) {
      if (swigCMemOwn) {
        swigCMemOwn = false;
        throw new UnsupportedOperationException("C++ destructor does not have public access");
      }
      swigCPtr = 0;
    }
  }
}

What would be the best way to handle this in javacpp?

[saudet]

We can annotate the constructor with @NoDeallocator for that, since it's hard to detect all such situations automatically, but we could add detection for this case in particular...

[peskygnat]

Since the class is complete abstract other than the destructor, this seems to be the easy solution in the Config.

    infoMap.put(new Info("Object_I").purify(true));