[PATCH v3 6/7] gdb/python: add gdbpy_dict_wrapper:allocate_dict helper

[Matthieu Longo <matthieu.longo@arm.com>]

Python extension objects that support __dict__ must inherit from
gdbpy_dict_wrapper, a wrapper class that stores the PyObject
corresponding to the __dict__ attribute.

Currently, management of this dictionary is not centralized, and
each Python extension object implements its own logic to create,
access, and destroy it.

This patch focuses on the allocation of the dictionary, introduces
a new method, gdbpy_dict_wrapper::allocate_dict(), and
adapts the existing code to use this method.
---
 gdb/python/py-corefile.c  | 3 +--
 gdb/python/py-event.c     | 7 +++----
 gdb/python/py-inferior.c  | 3 +--
 gdb/python/py-infthread.c | 7 +++----
 gdb/python/py-objfile.c   | 7 +++----
 gdb/python/py-progspace.c | 3 +--
 gdb/python/py-ref.h       | 7 +++++++
 gdb/python/py-type.c      | 9 +++------
 8 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/gdb/python/py-corefile.c b/gdb/python/py-corefile.c
index de88a964efb..0c2821cb07e 100644
--- a/gdb/python/py-corefile.c
+++ b/gdb/python/py-corefile.c
@@ -132,8 +132,7 @@ gdbpy_core_file_from_inferior (inferior *inf)
      which requires that the 'inferior' be set to NULL.  */
   object->inferior = nullptr;
   object->mapped_files = nullptr;
-  object->dict = PyDict_New ();
-  if (object->dict == nullptr)
+  if (!object->allocate_dict ())
     return nullptr;
 
   /* Now that the gdb.Corefile has been successfully initialised and we know
diff --git a/gdb/python/py-event.c b/gdb/python/py-event.c
index 39e1dd9c75f..8192d1cefa0 100644
--- a/gdb/python/py-event.c
+++ b/gdb/python/py-event.c
@@ -31,11 +31,10 @@ create_event_object (PyTypeObject *py_type)
 {
   gdbpy_ref<event_object> event_obj (PyObject_New (event_object, py_type));
   if (event_obj == NULL)
-    return NULL;
+    return nullptr;
 
-  event_obj->dict = PyDict_New ();
-  if (!event_obj->dict)
-    return NULL;
+  if (!event_obj->allocate_dict ())
+    return nullptr;
 
   return event_obj;
 }
diff --git a/gdb/python/py-inferior.c b/gdb/python/py-inferior.c
index 4ad0ea1b264..eaf224fe808 100644
--- a/gdb/python/py-inferior.c
+++ b/gdb/python/py-inferior.c
@@ -224,8 +224,7 @@ inferior_to_inferior_object (struct inferior *inferior)
 
   inf_obj->inferior = inferior;
   inf_obj->threads = new thread_map_t ();
-  inf_obj->dict = PyDict_New ();
-  if (inf_obj->dict == nullptr)
+  if (!inf_obj->allocate_dict ())
     return nullptr;
 
   /* PyObject_New initializes the new object with a refcount of 1.  This counts
diff --git a/gdb/python/py-infthread.c b/gdb/python/py-infthread.c
index 0f29e9fb7a4..7afec0112fb 100644
--- a/gdb/python/py-infthread.c
+++ b/gdb/python/py-infthread.c
@@ -41,16 +41,15 @@ create_thread_object (struct thread_info *tp)
 
   gdbpy_ref<inferior_object> inf_obj = inferior_to_inferior_object (tp->inf);
   if (inf_obj == NULL)
-    return NULL;
+    return nullptr;
 
   thread_obj.reset (PyObject_New (thread_object, &thread_object_type));
   if (thread_obj == NULL)
-    return NULL;
+    return nullptr;
 
   thread_obj->thread = tp;
   thread_obj->inf_obj = (PyObject *) inf_obj.release ();
-  thread_obj->dict = PyDict_New ();
-  if (thread_obj->dict == nullptr)
+  if (!thread_obj->allocate_dict ())
     return nullptr;
 
   return thread_obj;
diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index bbe21d32549..daf1b44747c 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -201,12 +201,11 @@ objfpy_dealloc (PyObject *o)
 static bool
 objfpy_initialize (gdbpy_ref<objfile_object> &self)
 {
-  self->objfile = NULL;
-
-  self->dict = PyDict_New ();
-  if (self->dict == NULL)
+  if (!self->allocate_dict ())
     return false;
 
+  self->objfile = NULL;
+
   self->printers = PyList_New (0);
   if (self->printers == NULL)
     return false;
diff --git a/gdb/python/py-progspace.c b/gdb/python/py-progspace.c
index f2585103346..d1a8479588f 100644
--- a/gdb/python/py-progspace.c
+++ b/gdb/python/py-progspace.c
@@ -171,8 +171,7 @@ pspy_initialize (gdbpy_ref<pspace_object> &self)
 {
   self->pspace = NULL;
 
-  self->dict = PyDict_New ();
-  if (self->dict == NULL)
+  if (!self->allocate_dict ())
     return false;
 
   self->printers = PyList_New (0);
diff --git a/gdb/python/py-ref.h b/gdb/python/py-ref.h
index 0a56436634d..f0cdb38498e 100644
--- a/gdb/python/py-ref.h
+++ b/gdb/python/py-ref.h
@@ -77,6 +77,13 @@ struct gdbpy_dict_wrapper : public PyObject
     auto *wrapper = reinterpret_cast<gdbpy_dict_wrapper *> (self);
     return &wrapper->dict;
   }
+
+  bool
+  allocate_dict ()
+  {
+    dict = PyDict_New ();
+    return dict != nullptr;
+  }
 };
 
 #endif /* GDB_PYTHON_PY_REF_H */
diff --git a/gdb/python/py-type.c b/gdb/python/py-type.c
index ec4126d0589..0893da5aec9 100644
--- a/gdb/python/py-type.c
+++ b/gdb/python/py-type.c
@@ -93,12 +93,9 @@ field_new (void)
   gdbpy_ref<field_object> result (PyObject_New (field_object,
 						&field_object_type));
 
-  if (result != NULL)
-    {
-      result->dict = PyDict_New ();
-      if (!result->dict)
-	return NULL;
-    }
+  if (result != nullptr && !result->allocate_dict ())
+    return nullptr;
+
   return (PyObject *) result.release ();
 }
 
-- 
2.53.0