Re: [python][patch] And range method to type

[Phil Muldoon <pmuldoon at redhat dot com>]

On 12/04/2009 06:13 PM, Tom Tromey wrote:
>>>>>> "Phil" == Phil Muldoon <pmuldoon@redhat.com> writes:
> 
> Phil> This patch adds a "range" method for GDB.Types.  It only supports types
> Phil> that support a range, or the range type itself.
> 
> Phil> +  if (TYPE_CODE (type) != TYPE_CODE_ARRAY &&
> Phil> +      TYPE_CODE (type) != TYPE_CODE_STRING &&
> Phil> +      TYPE_CODE (type) != TYPE_CODE_RANGE)
> 
> In the GNU style, the "&&"s go at the start of the line.


OK.


> 
> I think this code should check for failures from PyLong_FromLong and
> PyTuple_SetItem.  I realize that is a pain, but if one of those does
> fail, a failure to check will yield weird problems.


OK, the new code has more robust error checking.


> Phil>  Return a type of pointer to this type." },
> Phil> +  { "range", typy_range, METH_NOARGS,
> Phil> +    "range () -> Tuple\n\
> 
> It should be "tuple", as that is the name of the returned type.


OK.

I've regenerated the patch. Thanks for the review! What do you think?

Cheers,

Phil

--

Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.647
diff -u -r1.647 gdb.texinfo
--- doc/gdb.texinfo	3 Dec 2009 21:19:48 -0000	1.647
+++ doc/gdb.texinfo	5 Dec 2009 09:11:25 -0000
@@ -19654,6 +19654,13 @@
 @code{volatile}.
 @end defmethod
 
+@defmethod Type range
+Return a Python @code{Tuple} object that contains two elements: the
+low bound of the argument type and the high bound of that type.  If
+the type does not have a range, @value{GDBN} will raise a
+@code{RuntimeError} exception.
+@end defmethod
+
 @defmethod Type reference
 Return a new @code{gdb.Type} object which represents a reference to this
 type.
Index: python/py-type.c
===================================================================
RCS file: /cvs/src/src/gdb/python/py-type.c,v
retrieving revision 1.3
diff -u -r1.3 py-type.c
--- python/py-type.c	3 Dec 2009 21:19:49 -0000	1.3
+++ python/py-type.c	5 Dec 2009 09:11:25 -0000
@@ -273,6 +273,70 @@
   return type_to_type_object (type);
 }
 
+/* Return the range of a type represented by SELF.  The return type is
+   a tuple.  The first element of the tuple contains the low bound,
+   while the second element of the tuple contains the high bound.  */
+static PyObject *
+typy_range (PyObject *self, PyObject *args)
+{
+  struct type *type = ((type_object *) self)->type;
+  PyObject *result;
+  PyObject *low_bound = NULL, *high_bound = NULL;
+  LONGEST low, high;
+
+  if (TYPE_CODE (type) != TYPE_CODE_ARRAY
+      && TYPE_CODE (type) != TYPE_CODE_STRING
+      && TYPE_CODE (type) != TYPE_CODE_RANGE)
+    {
+      PyErr_SetString (PyExc_RuntimeError,
+		       "This type does not have a range.");
+      return NULL;
+    }
+
+  switch (TYPE_CODE (type))
+    {
+    case TYPE_CODE_ARRAY:
+    case TYPE_CODE_STRING:
+      low = TYPE_LOW_BOUND (TYPE_INDEX_TYPE (type));
+      high = TYPE_HIGH_BOUND (TYPE_INDEX_TYPE (type));
+      break;
+    case TYPE_CODE_RANGE:
+      low = TYPE_LOW_BOUND (type);
+      high = TYPE_HIGH_BOUND (type);
+      break;
+    }
+
+  low_bound = PyLong_FromLong (low);
+  if (!low_bound)
+    goto failarg;
+
+  high_bound = PyLong_FromLong (high);
+  if (!high_bound)
+    goto failarg;
+
+  result = PyTuple_New (2);
+  if (!result)
+    goto failarg;
+
+  if (PyTuple_SetItem (result, 0, low_bound) != 0)
+    {
+      Py_DECREF (result);
+      goto failarg;
+    }
+  if (PyTuple_SetItem (result, 1, high_bound) != 0)
+    {
+      Py_DECREF (high_bound);
+      Py_DECREF (result);
+      return NULL;
+    }
+  return result;
+
+ failarg:
+  Py_XDECREF (high_bound);
+  Py_XDECREF (low_bound);
+  return NULL;
+}
+
 /* Return a Type object which represents a reference to SELF.  */
 static PyObject *
 typy_reference (PyObject *self, PyObject *args)
@@ -699,6 +763,9 @@
   { "pointer", typy_pointer, METH_NOARGS,
     "pointer () -> Type\n\
 Return a type of pointer to this type." },
+  { "range", typy_range, METH_NOARGS,
+    "range () -> tuple\n\
+Return a tuple containing the lower and upper range for this type."},
   { "reference", typy_reference, METH_NOARGS,
     "reference () -> Type\n\
 Return a type of reference to this type." },
Index: testsuite/gdb.python/py-type.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.python/py-type.exp,v
retrieving revision 1.1
diff -u -r1.1 py-type.exp
--- testsuite/gdb.python/py-type.exp	3 Dec 2009 21:19:49 -0000	1.1
+++ testsuite/gdb.python/py-type.exp	5 Dec 2009 09:11:26 -0000
@@ -102,6 +102,28 @@
   gdb_test "python print fields\[1\].is_base_class" "False" "Check base class"
 }
 
+proc test_range {} {
+
+  # Test a valid range request.
+  gdb_py_test_silent_cmd "print ar" "print value" 1
+  gdb_py_test_silent_cmd "python ar = gdb.history (0)" "get value from history" 1
+  gdb_test "python print len(ar.type.range())" "2" "Check correct tuple length"
+  gdb_test "python print ar.type.range()\[0\]" "0" "Check low range"
+  gdb_test "python print ar.type.range()\[1\]" "1" "Check high range"
+
+  # Test a range request on a ranged type.
+  gdb_py_test_silent_cmd "print ar" "print value" 1
+  gdb_py_test_silent_cmd "python ar = gdb.history (0)" "get value from  history" 1
+  gdb_py_test_silent_cmd "python fields = ar.type.fields()" "get fields" 1
+  gdb_test "python print fields\[0\].type.range()\[0\]" "0" "Check range type low bound"
+  gdb_test "python print fields\[0\].type.range()\[1\]" "1" "Check range type high bound"
+
+  # Test where a range does not exist.
+  gdb_py_test_silent_cmd "print st" "print value" 1
+  gdb_py_test_silent_cmd "python st = gdb.history (0)" "get value from history" 1
+  gdb_test "python print st.type.range()" "RuntimeError: This type does not have a range.*" "Check range for non ranged type."
+}
+
 # Perform C Tests.
 build_inferior "c"
 restart_gdb "break to inspect struct and array."
@@ -112,3 +134,4 @@
 restart_gdb "break to inspect struct and array."
 test_fields "c++"
 test_base_class
+test_range