Merge branch 'master' into gqtech

1 files changed, 56 insertions, 0 deletions

diff --git a/common/handle_error.cc b/common/handle_error.cc
new file mode 100644
index 00000000..a06b5348
--- /dev/null
+++ b/common/handle_error.cc
@@ -0,0 +1,56 @@
+#include <boost/python.hpp>
+#include <Python.h>
+
+namespace py = boost::python;
+
+// Parses the value of the active python exception
+// NOTE SHOULD NOT BE CALLED IF NO EXCEPTION
+std::string parse_python_exception(){
+    PyObject *type_ptr = NULL, *value_ptr = NULL, *traceback_ptr = NULL;
+    // Fetch the exception info from the Python C API
+    PyErr_Fetch(&type_ptr, &value_ptr, &traceback_ptr);
+
+    // Fallback error
+    std::string ret("Unfetchable Python error");
+    // If the fetch got a type pointer, parse the type into the exception string
+    if(type_ptr != NULL){
+        py::handle<> h_type(type_ptr);
+        py::str type_pstr(h_type);
+        // Extract the string from the boost::python object
+        py::extract<std::string> e_type_pstr(type_pstr);
+        // If a valid string extraction is available, use it 
+        //  otherwise use fallback
+        if(e_type_pstr.check())
+            ret = e_type_pstr();
+        else
+            ret = "Unknown exception type";
+    }
+    // Do the same for the exception value (the stringification of the exception)
+    if(value_ptr != NULL){
+        py::handle<> h_val(value_ptr);
+        py::str a(h_val);
+        py::extract<std::string> returned(a);
+        if(returned.check())
+            ret +=  ": " + returned();
+        else
+            ret += std::string(": Unparseable Python error: ");
+    }
+    // Parse lines from the traceback using the Python traceback module
+    if(traceback_ptr != NULL){
+        py::handle<> h_tb(traceback_ptr);
+        // Load the traceback module and the format_tb function
+        py::object tb(py::import("traceback"));
+        py::object fmt_tb(tb.attr("format_tb"));
+        // Call format_tb to get a list of traceback strings
+        py::object tb_list(fmt_tb(h_tb));
+        // Join the traceback strings into a single string
+        py::object tb_str(py::str("\n").join(tb_list));
+        // Extract the string, check the extraction, and fallback in necessary
+        py::extract<std::string> returned(tb_str);
+        if(returned.check())
+            ret += ": " + returned();
+        else
+            ret += std::string(": Unparseable Python traceback");
+    }
+    return ret;
+}