Add JSONDecodeError

Fixes ultrajson#497

python/JSONtoObj.c

@@ -38,6 +38,7 @@ Numeric decoder derived from from TCL library
 
 #include <Python.h>
 #include <ultrajson.h>
+#include "ujson.h"
 
 
 //#define PRINTMARK() fprintf(stderr, "%s: MARK(%d)\n", __FILE__, __LINE__)
@@ -187,7 +188,7 @@ PyObject* JSONToObj(PyObject* self, PyObject *args, PyObject *kwargs)
     /*
     FIXME: It's possible to give a much nicer error message here with actual failing element in input etc*/
 
-    PyErr_Format (PyExc_ValueError, "%s", decoder.errorStr);
+    PyErr_Format (JSONDecodeError, "%s", decoder.errorStr);
 
     if (ret)
     {

python/ujson.c

@@ -38,6 +38,7 @@ Numeric decoder derived from from TCL library
 
 #include <Python.h>
 #include "version.h"
+#include "ujson.h"
 
 /* objToJSON */
 PyObject* objToJSON(PyObject* self, PyObject *args, PyObject *kwargs);
@@ -51,6 +52,8 @@ PyObject* objToJSONFile(PyObject* self, PyObject *args, PyObject *kwargs);
 /* JSONFileToObj */
 PyObject* JSONFileToObj(PyObject* self, PyObject *args, PyObject *kwargs);
 
+PyObject* JSONDecodeError;
+
 
 #define ENCODER_HELP_TEXT "Use ensure_ascii=false to output UTF-8. " \
     "Set encode_html_chars=True to encode < > & as unicode escape sequences. "\
@@ -188,5 +191,15 @@ PyMODINIT_FUNC PyInit_ujson(void)
     PyErr_Clear();
 #endif
 
+  JSONDecodeError = PyErr_NewException("ujson.JSONDecodeError", PyExc_ValueError, NULL);
+  Py_XINCREF(JSONDecodeError);
+  if (PyModule_AddObject(module, "JSONDecodeError", JSONDecodeError) < 0)
+  {
+    Py_XDECREF(JSONDecodeError);
+    Py_CLEAR(JSONDecodeError);
+    Py_DECREF(module);
+    return NULL;
+  }
+
   return module;
 }

python/ujson.h

@@ -0,0 +1 @@
+extern PyObject* JSONDecodeError;