1 files changed, 65 insertions, 0 deletions
diff --git a/xbmc/interfaces/python/CallbackHandler.cpp b/xbmc/interfaces/python/CallbackHandler.cpp
new file mode 100644
index 0000000..8fd31a7
--- /dev/null
+++ b/xbmc/interfaces/python/CallbackHandler.cpp
@@ -0,0 +1,65 @@
+/*
+ *  Copyright (C) 2005-2018 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#include "CallbackHandler.h"
+
+#include "LanguageHook.h"
+
+namespace XBMCAddon
+{
+  namespace Python
+  {
+    /**
+     * We are ASS-U-MEing that this construction is happening
+     *  within the context of a Python call. This way we can
+     *  store off the PyThreadState to later verify that we're
+     *  handling callbacks in the appropriate thread.
+     */
+    PythonCallbackHandler::PythonCallbackHandler()
+    {
+      XBMC_TRACE;
+      objectThreadState = PyThreadState_Get();
+    }
+
+    /**
+     * Now we are answering the question as to whether or not we are in the
+     *  PyThreadState that we were in when we started.
+     */
+    bool PythonCallbackHandler::isStateOk(AddonClass* obj)
+    {
+      XBMC_TRACE;
+      PyThreadState* state = PyThreadState_Get();
+      if (objectThreadState == state)
+      {
+        // make sure the interpreter is still active.
+        AddonClass::Ref<XBMCAddon::Python::PythonLanguageHook> lh(XBMCAddon::Python::PythonLanguageHook::GetIfExists(state->interp));
+        if (lh.isNotNull() && lh->HasRegisteredAddonClassInstance(obj) && lh.get() == obj->GetLanguageHook())
+          return true;
+      }
+      return false;
+    }
+
+    /**
+     * For this method we expect the PyThreadState to be passed as the user
+     *  data for the check.
+     *
+     * @todo This is a stupid way to get this information back to the handler.
+     *  there should be a more language neutral means.
+     */
+    bool PythonCallbackHandler::shouldRemoveCallback(AddonClass* obj, void* threadState)
+    {
+      XBMC_TRACE;
+      if (threadState == objectThreadState)
+        return true;
+
+      // we also want to remove the callback if the language hook no longer exists.
+      //   this is a belt-and-suspenders cleanup mechanism
+      return ! XBMCAddon::Python::PythonLanguageHook::IsAddonClassInstanceRegistered(obj);
+    }
+  }
+}