gdb: remove iterate_over_breakpoints function

Now that we have range functions that let us use ranged for loops, we
can remove iterate_over_breakpoints in favor of those, which are easier
to read and write.  This requires exposing the declaration of
all_breakpoints and all_breakpoints_safe in breakpoint.h, as well as the
supporting types.

Change some users of iterate_over_breakpoints to use all_breakpoints,
when they don't need to delete the breakpoint, and all_breakpoints_safe
otherwise.

gdb/ChangeLog:

	* breakpoint.h (iterate_over_breakpoints): Remove.  Update
	callers to use all_breakpoints or all_breakpoints_safe.
	(breakpoint_range, all_breakpoints, breakpoint_safe_range,
	all_breakpoints_safe): Move here.
	* breakpoint.c (all_breakpoints, all_breakpoints_safe): Make
	non-static.
	(iterate_over_breakpoints): Remove.
	* python/py-finishbreakpoint.c (bpfinishpy_detect_out_scope_cb):
	Return void.
	* python/py-breakpoint.c (build_bp_list): Add comment, reverse
	return value logic.
	* guile/scm-breakpoint.c (bpscm_build_bp_list): Return void.

Change-Id: Idde764a1f577de0423e4f2444a7d5cdb01ba5e48

gdb/python/py-breakpoint.c

@@ -898,25 +898,24 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
   return 0;
 }
 
-
+/* Append to LIST the breakpoint Python object associated to B.
+
+   Return true on success.  Return false on failure, with the Python error
+   indicator set.  */
 
 static bool
 build_bp_list (struct breakpoint *b, PyObject *list)
 {
   PyObject *bp = (PyObject *) b->py_bp_object;
-  int iserr = 0;
 
   /* Not all breakpoints will have a companion Python object.
      Only breakpoints that were created via bppy_new, or
      breakpoints that were created externally and are tracked by
      the Python Scripting API.  */
-  if (bp)
-    iserr = PyList_Append (list, bp);
-
-  if (iserr == -1)
+  if (bp == nullptr)
     return true;
 
-  return false;
+  return PyList_Append (list, bp) == 0;
 }
 
 /* Static function to return a tuple holding all breakpoints.  */
@@ -931,15 +930,11 @@ gdbpy_breakpoints (PyObject *self, PyObject *args)
   if (list == NULL)
     return NULL;
 
-  /* If iterate_over_breakpoints returns non NULL it signals an error
-     condition.  In that case abandon building the list and return
-     NULL.  */
-  auto callback = [&] (breakpoint *bp)
-    {
-      return build_bp_list(bp, list.get ());
-    };
-  if (iterate_over_breakpoints (callback) != NULL)
-    return NULL;
+  /* If build_bp_list returns false, it signals an error condition.  In that
+     case abandon building the list and return nullptr.  */
+  for (breakpoint *bp : all_breakpoints ())
+    if (!build_bp_list (bp, list.get ()))
+      return nullptr;
 
   return PyList_AsTuple (list.get ());
 }