Change event code to use gdbpy_ref

This changes the event code in the Python layer to use
gdbpy_ref, simplifying the logic in many places.

It also changes evpy_emit_event not to steal a reference to its
argument.  This is simpler to do now that gdbpy_ref is in use;
it's also a reasonable cleanup in its own right.  While doing this I
realized that evpy_emit_event should not be calling gdbpy_print_stack
(all the outermost callers do this if needed), so I removed this as
well.

2017-01-10  Tom Tromey  <tom@tromey.com>

	* python/py-threadevent.c (create_thread_event_object): Use
	gdbpy_ref.
	* python/py-stopevent.c (create_stop_event_object): Simplify.
	(emit_stop_event): Use gdbpy_ref.
	* python/py-signalevent.c (create_signal_event_object): Use
	gdbpy_ref.
	* python/py-newobjfileevent.c (create_new_objfile_event_object)
	(emit_new_objfile_event, create_clear_objfiles_event_object)
	(emit_clear_objfiles_event): Use gdbpy_ref.
	* python/py-infevents.c (create_inferior_call_event_object)
	(create_register_changed_event_object)
	(create_memory_changed_event_object, emit_inferior_call_event)
	(emit_memory_changed_event, emit_register_changed_event): Use
	gdbpy_ref.
	* python/py-exitedevent.c (create_exited_event_object)
	(emit_exited_event): Use gdbpy_ref.
	* python/py-event.h (evpy_emit_event): Remove
	CPYCHECKER_STEALS_REFERENCE_TO_ARG annotation.
	* python/py-event.c (evpy_emit_event): Use gdbpy_ref.
	* python/py-continueevent.c (emit_continue_event): Use
	gdbpy_ref.
	* python/py-breakpoint.c (gdbpy_breakpoint_created)
	(gdbpy_breakpoint_deleted, gdbpy_breakpoint_modified): Use
	gdbpy_ref.
	* python/py-bpevent.c (create_breakpoint_event_object): Use
	gdbpy_ref.

1 files changed, 40 insertions, 98 deletions

diff --git a/gdb/python/py-infevents.c b/gdb/python/py-infevents.c
index 2e318710491..23bf57b53da 100644
--- a/gdb/python/py-infevents.c
+++ b/gdb/python/py-infevents.c
@@ -19,6 +19,7 @@
 
 #include "defs.h"
 #include "py-event.h"
+#include "py-ref.h"
 
 extern PyTypeObject inferior_call_pre_event_object_type
     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("event_object");
@@ -36,52 +37,36 @@ static PyObject *
 create_inferior_call_event_object (inferior_call_kind flag, ptid_t ptid,
 				   CORE_ADDR addr)
 {
-  PyObject *event;
-  PyObject *ptid_obj = NULL;
-  PyObject *addr_obj = NULL;
+  gdbpy_ref event;
   int failed;
-  struct cleanup *cleanups;
-  struct cleanup *member_cleanups;
 
   switch (flag)
     {
     case INFERIOR_CALL_PRE:
-      event = create_event_object (&inferior_call_pre_event_object_type);
+      event.reset (create_event_object (&inferior_call_pre_event_object_type));
       break;
     case INFERIOR_CALL_POST:
-      event = create_event_object (&inferior_call_post_event_object_type);
+      event.reset (create_event_object (&inferior_call_post_event_object_type));
       break;
     default:
-      return NULL;
+      gdb_assert_not_reached ("invalid inferior_call_kind");
     }
 
-  cleanups = make_cleanup_py_decref (event);
-
-  ptid_obj = gdbpy_create_ptid_object (ptid);
+  gdbpy_ref ptid_obj (gdbpy_create_ptid_object (ptid));
   if (ptid_obj == NULL)
-    goto fail;
-  member_cleanups = make_cleanup_py_decref (ptid_obj);
+    return NULL;
 
-  failed = evpy_add_attribute (event, "ptid", ptid_obj) < 0;
-  if (failed)
-    goto fail;
+  if (evpy_add_attribute (event.get (), "ptid", ptid_obj.get ()) < 0)
+    return NULL;
 
-  addr_obj = PyLong_FromLongLong (addr);
+  gdbpy_ref 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;
+    return NULL;
 
-  do_cleanups (member_cleanups);
-  discard_cleanups (cleanups);
-  return event;
+  if (evpy_add_attribute (event.get (), "address", addr_obj.get ()) < 0)
+    return NULL;
 
- fail:
-  do_cleanups (cleanups);
-  return NULL;
+  return event.release ();
 }
 
 /* Construct a gdb.RegisterChangedEvent containing the affected
@@ -91,44 +76,25 @@ static PyObject *
 create_register_changed_event_object (struct frame_info *frame, 
 				      int regnum)
 {
-  PyObject *event;
-  PyObject *frame_obj = NULL;
-  PyObject *regnum_obj = NULL;
-  int failed;
-  struct cleanup *cleanups;
-  struct cleanup *member_cleanups;
-
-  event = create_event_object (&register_changed_event_object_type);
+  gdbpy_ref 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);
+  gdbpy_ref frame_obj (frame_info_to_frame_object (frame));
   if (frame_obj == NULL)
-    goto fail;
-  member_cleanups = make_cleanup_py_decref (frame_obj);
+    return NULL;
 
-  failed = evpy_add_attribute (event, "frame", frame_obj) < 0;
-  if (failed)
-    goto fail;
+  if (evpy_add_attribute (event.get (), "frame", frame_obj.get ()) < 0)
+    return NULL;
 
-  regnum_obj = PyLong_FromLongLong (regnum);
+  gdbpy_ref 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;
+    return NULL;
 
-  do_cleanups (member_cleanups);
-  discard_cleanups (cleanups);
-  return event;
+  if (evpy_add_attribute (event.get (), "regnum", regnum_obj.get ()) < 0)
+    return NULL;
 
- fail:
-  do_cleanups (cleanups);
-  return NULL;
+  return event.release ();
 }
 
 /* Construct a gdb.MemoryChangedEvent describing the extent of the
@@ -137,44 +103,26 @@ create_register_changed_event_object (struct frame_info *frame,
 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;
-  struct cleanup *member_cleanups;
-
-  event = create_event_object (&memory_changed_event_object_type);
+  gdbpy_ref 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);
+  gdbpy_ref addr_obj (PyLong_FromLongLong (addr));
   if (addr_obj == NULL)
-    goto fail;
-  member_cleanups = make_cleanup_py_decref (addr_obj);
+    return NULL;
 
-  failed = evpy_add_attribute (event, "address", addr_obj) < 0;
-  if (failed)
-    goto fail;
+  if (evpy_add_attribute (event.get (), "address", addr_obj.get ()) < 0)
+    return NULL;
 
-  len_obj = PyLong_FromLong (len);
+  gdbpy_ref 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;
+    return NULL;
 
-  do_cleanups (member_cleanups);
-  discard_cleanups (cleanups);
-  return event;
+  if (evpy_add_attribute (event.get (), "length", len_obj.get ()) < 0)
+    return NULL;
 
- fail:
-  do_cleanups (cleanups);
-  return NULL;
+  return event.release ();
 }
 
 /* Callback function which notifies observers when an event occurs which
@@ -186,14 +134,12 @@ int
 emit_inferior_call_event (inferior_call_kind flag, ptid_t thread,
 			  CORE_ADDR addr)
 {
-  PyObject *event;
-
   if (evregpy_no_listeners_p (gdb_py_events.inferior_call))
     return 0;
 
-  event = create_inferior_call_event_object (flag, thread, addr);
+  gdbpy_ref event (create_inferior_call_event_object (flag, thread, addr));
   if (event != NULL)
-    return evpy_emit_event (event, gdb_py_events.inferior_call);
+    return evpy_emit_event (event.get (), gdb_py_events.inferior_call);
   return -1;
 }
 
@@ -203,14 +149,12 @@ emit_inferior_call_event (inferior_call_kind flag, ptid_t thread,
 int
 emit_memory_changed_event (CORE_ADDR addr, ssize_t len)
 {
-  PyObject *event;
-
   if (evregpy_no_listeners_p (gdb_py_events.memory_changed))
     return 0;
 
-  event = create_memory_changed_event_object (addr, len);
+  gdbpy_ref event (create_memory_changed_event_object (addr, len));
   if (event != NULL)
-    return evpy_emit_event (event, gdb_py_events.memory_changed);
+    return evpy_emit_event (event.get (), gdb_py_events.memory_changed);
   return -1;
 }
 
@@ -220,14 +164,12 @@ emit_memory_changed_event (CORE_ADDR addr, ssize_t len)
 int
 emit_register_changed_event (struct frame_info* frame, int regnum)
 {
-  PyObject *event;
-
   if (evregpy_no_listeners_p (gdb_py_events.register_changed))
     return 0;
 
-  event = create_register_changed_event_object (frame, regnum);
+  gdbpy_ref event (create_register_changed_event_object (frame, regnum));
   if (event != NULL)
-    return evpy_emit_event (event, gdb_py_events.register_changed);
+    return evpy_emit_event (event.get (), gdb_py_events.register_changed);
   return -1;
 }