1 files changed, 58 insertions, 0 deletions
diff --git a/include/o3tl/safeCoInitUninit.hxx b/include/o3tl/safeCoInitUninit.hxx
new file mode 100644
index 0000000000..0ceb4a9746
--- /dev/null
+++ b/include/o3tl/safeCoInitUninit.hxx
@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#if defined _WIN32
+#include <prewin.h>
+
+// for CoInitializeEx / CoUninitialize
+#include <combaseapi.h>
+
+#include <postwin.h>
+
+// for std::abort
+#include <cstdlib>
+
+namespace o3tl
+{
+// Helpers for safe calls to CoInitializeEx and CoUninitialize in MSVC
+// Indeed if a thread has been already initialized with a concurrency model
+// (in LO case COINIT_APARTMENTTHREADED or COINIT_MULTITHREADED)
+// CoInitializeEx can't succeed without calling first CoUninitialize
+// also, CoUninitialize must be called the number of times CoInitializeEx has been called
+inline HRESULT safeCoInitializeEx(DWORD dwCoInit, int& nbReinit)
+{
+    HRESULT hr;
+    while ((hr = CoInitializeEx(nullptr, dwCoInit)) == RPC_E_CHANGED_MODE)
+    {
+        // so we're in RPC_E_CHANGED_MODE case
+        // the pb was it was already initialized with a different concurrency model
+        // close this init
+        CoUninitialize();
+        // and increment counter for dtr part
+        ++nbReinit;
+
+        // and keep on the loop if there were multi initializations
+    }
+    if (FAILED(hr))
+        std::abort();
+    return hr;
+}
+
+inline void safeCoUninitializeReinit(DWORD dwCoInit, int nbReinit)
+{
+    CoUninitialize();
+    // Put back all the inits, if there were, before the use of the caller to safeCoInitializeEx
+    for (int i = 0; i < nbReinit; ++i)
+        CoInitializeEx(nullptr, dwCoInit);
+}
+}
+#endif
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */