[python] python-utils.c (python_string_to_unicode): Always return a new reference.

[python] python-utils.c (python_string_to_unicode): Always return a new reference.

[Phil Muldoon]

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Hi,

The python_string_to_unicode function previously returned either a 
borrowed or new reference.  This depended on some internal unicode 
versus encoded string checks.  Because of the new versus borrowed 
reference question, and the inability to determine which was 
subsequently returned, this brought ambiguity to the clean-up decisions 
around this function.  This patch removes the ambiguity by altering 
python_string_to_unicode to always return a new reference, and alters 
the consumers of this function to deal with this new behaviour 
appropriately.

This patch does not increase or decrease the number of regressions with 
make check. Tested and built on Fedora 10 x86_64.

2009-02-26  Phil Muldoon  <pmuldoon@redhat.com>

             * python/python-utils.c (python_string_to_unicode): Always 
return
              a new reference.
              (python_string_to_target_string): Decrement transient python
              instance.
              (python_string_to_host_string): Likewise.



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Index: gdb/python/python-utils.c
===================================================================
RCS file: /cvs/src/src/gdb/python/python-utils.c,v
retrieving revision 1.5
diff -u -r1.5 python-utils.c
--- gdb/python/python-utils.c	5 Feb 2009 21:16:09 -0000	1.5
+++ gdb/python/python-utils.c	26 Feb 2009 08:20:17 -0000
@@ -81,7 +81,11 @@
   /* If obj is already a unicode string, just return it.
      I wish life was always that simple...  */
   if (PyUnicode_Check (obj))
-    unicode_str = obj;
+    {
+      unicode_str = obj;
+      Py_INCREF (obj);
+    }
+  
   else if (PyString_Check (obj))
     unicode_str = PyUnicode_FromEncodedObject (obj, host_charset (), NULL);
   else
@@ -136,12 +140,15 @@
 python_string_to_target_string (PyObject *obj)
 {
   PyObject *str;
+  char *result;
 
   str = python_string_to_unicode (obj);
   if (str == NULL)
     return NULL;
 
-  return unicode_to_target_string (str);
+  result = unicode_to_target_string (str);
+  Py_DECREF (str);
+  return result;
 }
 
 /* Converts a python string (8-bit or unicode) to a target string in
@@ -152,12 +159,15 @@
 python_string_to_host_string (PyObject *obj)
 {
   PyObject *str;
+  char *result;
 
   str = python_string_to_unicode (obj);
   if (str == NULL)
     return NULL;
 
-  return unicode_to_encoded_string (str, host_charset ());
+  result = unicode_to_encoded_string (str, host_charset ()); 
+  Py_DECREF (str);
+  return result;
 }
 
 /* Converts a target string of LENGTH bytes in the target's charset to a

Re: [python] python-utils.c (python_string_to_unicode): Always return a new reference.

[Tom Tromey]

>>>>> "Phil" == Phil Muldoon <pmuldoon@redhat.com> writes:

Phil> 2009-02-26  Phil Muldoon  <pmuldoon@redhat.com>
Phil>             * python/python-utils.c (python_string_to_unicode): Always
Phil> return
Phil>              a new reference.
[...]

This is ok.

thanks,
Tom