From 8b43a644b13fdcc18463cee150eeb6613fc29ae7 Mon Sep 17 00:00:00 2001
From: Thibaut Vermeulen <thibaut.vermeulen@rte-france.com>
Date: Wed, 4 May 2022 18:23:39 +0200
Subject: [PATCH] python service wrapper: add state management for blocking IO
 in python

---
 pyiec61850/iec61850.i               |  6 +++
 pyiec61850/servicePythonWrapper.hpp | 63 +++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 pyiec61850/servicePythonWrapper.hpp

diff --git a/pyiec61850/iec61850.i b/pyiec61850/iec61850.i
index e4542544..254fec64 100644
--- a/pyiec61850/iec61850.i
+++ b/pyiec61850/iec61850.i
@@ -154,3 +154,9 @@ void CommParameters_setDstAddress(CommParameters *gooseCommParameters,
                                   uint8_t dst_mac_4,
                                   uint8_t dst_mac_5);
 
+
+/* Wrapper for synchronous functions */
+%{
+#include "servicePythonWrapper.hpp"
+%}
+%include "servicePythonWrapper.hpp"
diff --git a/pyiec61850/servicePythonWrapper.hpp b/pyiec61850/servicePythonWrapper.hpp
new file mode 100644
index 00000000..369e86c3
--- /dev/null
+++ b/pyiec61850/servicePythonWrapper.hpp
@@ -0,0 +1,63 @@
+#ifndef PYIEC61850_SERVICEPYTHONWRAPPER_HPP
+#define PYIEC61850_SERVICEPYTHONWRAPPER_HPP
+
+#include "iec61850_client.h"
+#include <Python.h>
+
+
+class PyThreadStateSave
+{
+public:
+    PyThreadStateSave(void)
+    {
+        if (PyGILState_Check())
+            state = PyEval_SaveThread();
+        else
+            state = nullptr;
+    }
+
+    ~PyThreadStateSave(void)
+    {
+        if (state)
+            PyEval_RestoreThread(state);
+    }
+
+private:
+    PyThreadState* state;
+};
+
+/*
+Wrapping of synchronous functions to prevent deadlocks
+*/
+static MmsValue* 
+pyWrap_IedConnection_readObject(IedConnection con, IedClientError* error, const char* objRef, FunctionalConstraint fc)
+{
+    PyThreadStateSave gilStateSave;
+    return IedConnection_readObject(con, error, objRef, fc);
+}
+
+static void
+pyWrap_IedConnection_writeObject(IedConnection con, IedClientError* error, const char* objectReference,
+        FunctionalConstraint fc, MmsValue* value)
+{
+    PyThreadStateSave gilStateSave;
+    IedConnection_writeObject(con, error, objectReference, fc, value);
+}
+
+static void 
+pyWrap_IedConnection_setRCBValues(IedConnection con, IedClientError* error, ClientReportControlBlock rcb, uint32_t parametersMask, 
+        bool singleRequest)
+{
+    PyThreadStateSave gilStateSave;
+    IedConnection_setRCBValues(con, error, rcb, parametersMask, singleRequest);
+}
+
+static ClientReportControlBlock 
+pyWrap_IedConnection_getRCBValues(IedConnection con, IedClientError* error, const char* rcbReference,
+        ClientReportControlBlock updateRcb)
+{
+    PyThreadStateSave gilStateSave;
+    return IedConnection_getRCBValues(con, error, rcbReference, updateRcb);
+}
+
+#endif