Remove memory leaks of strings/Unicode objects passed into the character

data and default handlers -- a new reference was being passed to
Py_BuildValue() for the "O" format character; using "N" plugs the leak.

Fixed two other (minor) leaks that occurred on various error conditions.

Removed uses of the UNLESS macro, which makes code hard to read, and is
Evil.

Modules/pyexpat.c

@@ -93,7 +93,7 @@ conv_atts_using_string(XML_Char **atts)
 static PyObject *
 conv_atts_using_unicode(XML_Char **atts)
 {
-    PyObject *attrs_obj = NULL;
+    PyObject *attrs_obj;
     XML_Char **attrs_p, **attrs_k = NULL;
     int attrs_len;
 
@@ -121,6 +121,8 @@ conv_atts_using_unicode(XML_Char **atts)
             }
             if (PyDict_SetItem(attrs_obj, attr_str, value_str) < 0) {
                 Py_DECREF(attrs_obj);
+                Py_DECREF(attr_str);
+                Py_DECREF(value_str);
                 attrs_obj = NULL;
                 goto finally;
             }
@@ -275,11 +277,11 @@ VOID_HANDLER(ProcessingInstruction,
 #if PY_MAJOR_VERSION == 1 && PY_MINOR_VERSION < 6
 VOID_HANDLER(CharacterData, 
 	      (void *userData, const XML_Char *data, int len), 
-	      ("(O)", conv_string_len_to_utf8(data,len)))
+	      ("(N)", conv_string_len_to_utf8(data,len)))
 #else
 VOID_HANDLER(CharacterData, 
 	      (void *userData, const XML_Char *data, int len), 
-	      ("(O)", (self->returns_unicode 
+	      ("(N)", (self->returns_unicode 
 		       ? conv_string_len_to_unicode(data,len) 
 		       : conv_string_len_to_utf8(data,len))))
 #endif
@@ -332,21 +334,21 @@ VOID_HANDLER(EndCdataSection,
 #if PY_MAJOR_VERSION == 1 && PY_MINOR_VERSION < 6
 VOID_HANDLER(Default,
 	      (void *userData,  const XML_Char *s, int len),
-	      ("(O)", conv_string_len_to_utf8(s,len)))
+	      ("(N)", conv_string_len_to_utf8(s,len)))
 
 VOID_HANDLER(DefaultHandlerExpand,
 	      (void *userData,  const XML_Char *s, int len),
-	      ("(O)", conv_string_len_to_utf8(s,len)))
+	      ("(N)", conv_string_len_to_utf8(s,len)))
 #else
 VOID_HANDLER(Default,
 	      (void *userData,  const XML_Char *s, int len),
-	      ("(O)", (self->returns_unicode 
+	      ("(N)", (self->returns_unicode 
 		       ? conv_string_len_to_unicode(s,len) 
 		       : conv_string_len_to_utf8(s,len))))
 
 VOID_HANDLER(DefaultHandlerExpand,
 	      (void *userData,  const XML_Char *s, int len),
-	      ("(O)", (self->returns_unicode 
+	      ("(N)", (self->returns_unicode 
 		       ? conv_string_len_to_unicode(s,len) 
 		       : conv_string_len_to_utf8(s,len))))
 #endif
@@ -370,49 +372,6 @@ RC_HANDLER(int, ExternalEntityRef,
 		
 
 
-/* File reading copied from cPickle */
-
-#define UNLESS(E) if (!(E))
-
-/*
-static int 
-read_other(xmlparseobject *self, char **s, int  n) {
-    PyObject *bytes=NULL, *str=NULL, *arg=NULL;
-    int res = -1;
-
-    UNLESS(bytes = PyInt_FromLong(n)) {
-        if (!PyErr_Occurred())
-            PyErr_SetNone(PyExc_EOFError);
-
-        goto finally;
-    }
-
-    UNLESS(arg)
-        UNLESS(arg = PyTuple_New(1))
-            goto finally;
-
-    Py_INCREF(bytes);
-    if (PyTuple_SetItem(arg, 0, bytes) < 0)
-        goto finally;
-
-    UNLESS(str = PyObject_CallObject(self->read, arg))
-        goto finally;
-
-    *s = PyString_AsString(str);
-
-    res = n;
-
-finally:
-     Py_XDECREF(arg);
-     Py_XDECREF(bytes);
-
-     return res;
-}
-
-*/
-
-
-
 /* ---------------------------------------------------------------- */
 
 static char xmlparse_Parse__doc__[] = 
@@ -443,6 +402,8 @@ xmlparse_Parse(xmlparseobject *self, PyObject *args)
     return PyInt_FromLong(rv);
 }
 
+/* File reading copied from cPickle */
+
 #define BUF_SIZE 2048
 
 static int
@@ -453,23 +414,24 @@ readinst(char *buf, int buf_size, PyObject *meth)
     PyObject *str = NULL;
     int len = -1;
 
-    UNLESS(bytes = PyInt_FromLong(buf_size)) {
+    fprintf(stderr, "calling readinst()\n");
+
+    if ((bytes = PyInt_FromLong(buf_size)) == NULL) {
         if (!PyErr_Occurred())
             PyErr_SetNone(PyExc_EOFError);
         goto finally;
     }
-    UNLESS(arg)
-        UNLESS(arg = PyTuple_New(1))
+    if ((arg = PyTuple_New(1)) == NULL)
         goto finally;
 
-    if (PyTuple_SetItem(arg, 0, bytes) < 0)
+    if (PyTuple_SET_ITEM(arg, 0, bytes) < 0)
         goto finally;
 
-    UNLESS(str = PyObject_CallObject(meth, arg))
+    if ((str = PyObject_CallObject(meth, arg)) == NULL)
         goto finally;
 
     /* XXX what to do if it returns a Unicode string? */
-    UNLESS(PyString_Check(str)) {
+    if (!PyString_Check(str)) {
         PyErr_Format(PyExc_TypeError, 
                      "read() did not return a string object (type=%.400s)",
                      str->ob_type->tp_name);
@@ -485,9 +447,9 @@ readinst(char *buf, int buf_size, PyObject *meth)
         goto finally;
     }
     memcpy(buf, PyString_AsString(str), len);
-    Py_XDECREF(str);
 finally:
     Py_XDECREF(arg);
+    Py_XDECREF(str);
     return len;
 }
 
@@ -511,7 +473,8 @@ xmlparse_ParseFile(xmlparseobject *self, PyObject *args)
     }
     else{
         fp = NULL;
-        UNLESS(readmethod = PyObject_GetAttrString(f, "read")) {
+        readmethod = PyObject_GetAttrString(f, "read");
+        if (readmethod == NULL) {
             PyErr_Clear();
             PyErr_SetString(PyExc_TypeError, 
                             "argument must have 'read' attribute");