Re: [PATCH v7] Events when inferior is modified

[Doug Evans <dje at google dot com>]

Doug Evans writes:
 > [...]
 > Alas our use of thread ids is a bit, umm, confusing
 > (in more ways than one! :-().
 > Here, it's not guaranteed that ptid.lwp has something useful,
 > and it may be that the target uses ptid.tid instead.
 > 
 > See python/py-infthread.c:thpy_get_ptid.
 > I think we should make that non-static and use that here.

Well, more specifically, split it into two and export a routine
that builds a python ptid tuple from a ptid_t.

 > IOW, pass the whole ptid_t to the event.
 > 
 >  > +  if (tid_obj == NULL)
 >  > +    goto fail;
 >  > +  make_cleanup_py_decref (tid_obj);
 >  > +
 >  > +  failed = evpy_add_attribute (event, "tid", tid_obj) < 0;
 >  > +  if (failed)
 >  > +    goto fail;
 >  > +
 >  > +  addr_obj = PyLong_FromLongLong (addr);
 >  > +  if (addr_obj == NULL)
 >  > +    goto fail;
 >  > +  make_cleanup_py_decref (addr_obj);
 >  > +
 >  > +  failed = evpy_add_attribute (event, "address", addr_obj) < 0;
 >  > +  if (failed)
 >  > +    goto fail;
 >  > +
 > 
 > Run the cleanups here as well as for the fail case.

Well, more specifically (bleah) ...

E.g., the addr_obj attribute will have two references when we return
here.  We want it to only have one: when the event goes away
we want addr_obj to go away too.

Obviously we don't want to decref the event object itself.

This applies to my other "Run the cleanups ..." comments below.

 > 
 >  > +  return event;
 >  > +
 >  > + fail:
 >  > +  do_cleanups (cleanups);
 >  > +  return NULL;
 >  > +}
 >  > +
 >  > +/* Construct a gdb.RegisterChangedEvent containing the affected
 >  > +   register number. */
 >  > +
 >  > +static PyObject *
 >  > +create_register_changed_event_object (struct frame_info *frame, 
 >  > +				      short regnum)
 >  > +{
 >  > +  PyObject * event;
 >  > +  PyObject *frame_obj = NULL;
 >  > +  PyObject *regnum_obj = NULL;
 >  > +  int failed;
 >  > +  struct cleanup *cleanups;
 >  > +
 >  > +  event = create_event_object (&register_changed_event_object_type);
 >  > +  if (event == NULL)
 >  > +    return NULL;
 >  > +
 >  > +  cleanups = make_cleanup_py_decref (event);
 >  > +
 >  > +  frame_obj = frame_info_to_frame_object (frame);
 >  > +  if (frame_obj == NULL)
 >  > +    goto fail;
 >  > +  make_cleanup_py_decref (frame_obj);
 >  > +
 >  > +  failed = evpy_add_attribute (event, "frame", frame_obj) < 0;
 >  > +  if (failed)
 >  > +    goto fail;
 >  > +
 >  > +  regnum_obj = PyLong_FromLongLong (regnum);
 >  > +  if (regnum_obj == NULL)
 >  > +    goto fail;
 >  > +  make_cleanup_py_decref (regnum_obj);
 >  > +
 >  > +  failed = evpy_add_attribute (event, "regnum", regnum_obj) < 0;
 >  > +  if (failed)
 >  > +    goto fail;
 >  > +
 > 
 > Run the cleanups here as well as for the fail case.
 > 
 >  > +  return event;
 >  > +
 >  > + fail:
 >  > +  do_cleanups (cleanups);
 >  > +  return NULL;
 >  > +}
 >  > +
 >  > +/* Construct a gdb.MemoryChangedEvent describing the extent of the
 >  > +   affected memory. */
 >  > +
 >  > +static PyObject *
 >  > +create_memory_changed_event_object (CORE_ADDR addr, ssize_t len)
 >  > +{
 >  > +  PyObject * event;
 >  > +  PyObject *addr_obj = NULL;
 >  > +  PyObject *len_obj = NULL;
 >  > +  int failed;
 >  > +  struct cleanup *cleanups;
 >  > +
 >  > +  event = create_event_object (&memory_changed_event_object_type);
 >  > +
 >  > +  if (event == NULL)
 >  > +    return NULL;
 >  > +  cleanups = make_cleanup_py_decref (event);
 >  > +
 >  > +  addr_obj = PyLong_FromLongLong (addr);
 >  > +  if (addr_obj == NULL)
 >  > +    goto fail;
 >  > +  make_cleanup_py_decref (addr_obj);
 >  > +
 >  > +  failed = evpy_add_attribute (event, "address", addr_obj) < 0;
 >  > +  if (failed)
 >  > +    goto fail;
 >  > +
 >  > +  len_obj = PyLong_FromLong (len);
 >  > +  if (len_obj == NULL)
 >  > +    goto fail;
 >  > +  make_cleanup_py_decref (len_obj);
 >  > +
 >  > +  failed = evpy_add_attribute (event, "length", len_obj) < 0;
 >  > +  if (failed)
 >  > +    goto fail;
 >  > +
 > 
 > Run the cleanups here as well as for the fail case.
 > 
 >  > +  return event;
 >  > +
 >  > + fail:
 >  > +  do_cleanups (cleanups);
 >  > +  return NULL;
 >  > +}
 >  > +
 > [...]