Iterate over 'struct varobj_item' instead of PyObject

In previous patch, "saved_item" is still a PyOjbect and iteration is
still performed over PyObject.  This patch continues to decouple
iteration from python code, so it changes its type to "struct
varobj_item *", so that the iterator itself is independent of python.

 V2:
 - Call varobj_delete_iter in free_variable.
 - Fix changelog entries.
 - Use XNEW.

 V3:
 - Return NULL early in py_varobj_iter_next if gdb_python_initialized
   is false.

gdb:

2014-06-12  Pedro Alves  <pedro@codesourcery.com>
	    Yao Qi  <yao@codesourcery.com>

	* python/py-varobj.c (py_varobj_iter_next): Return NULL if
	gdb_python_initialized is false.  Move some code from varobj.c.
	* varobj-iter.h (struct varobj_item): Moved from varobj.c.
	* varobj.c: Move "varobj-iter.h" inclusion earlier.
	(struct varobj_item): Moved to varobj-iter.h".
	(varobj_clear_saved_item): New function.
	(update_dynamic_varobj_children): Move python-related code to
	py-varobj.c.
	(free_variable): Call varobj_clear_saved_item and
	varobj_iter_delete.

1 files changed, 19 insertions, 1 deletions

diff --git a/gdb/python/py-varobj.c b/gdb/python/py-varobj.c
index 2b95348..7dfe67c 100644
--- a/gdb/python/py-varobj.c
+++ b/gdb/python/py-varobj.c
@@ -54,6 +54,12 @@ py_varobj_iter_next (struct varobj_iter *self)
   struct py_varobj_iter *t = (struct py_varobj_iter *) self;
   struct cleanup *back_to;
   PyObject *item;
+  PyObject *py_v;
+  varobj_item *vitem;
+  const char *name = NULL;
+
+  if (!gdb_python_initialized)
+    return NULL;
 
   back_to = varobj_ensure_python_env (self->var);
 
@@ -101,9 +107,21 @@ py_varobj_iter_next (struct varobj_iter *self)
 	}
     }
 
+  if (!PyArg_ParseTuple (item, "sO", &name, &py_v))
+    {
+      gdbpy_print_stack ();
+      error (_("Invalid item from the child list"));
+    }
+
+  vitem = xmalloc (sizeof *vitem);
+  vitem->value = convert_value_from_python (py_v);
+  if (vitem->value == NULL)
+    gdbpy_print_stack ();
+  vitem->name = xstrdup (name);
+
   self->next_raw_index++;
   do_cleanups (back_to);
-  return item;
+  return vitem;
 }
 
 /* The 'vtable' of pretty-printed python varobj iterators.  */