output/wasapi: move COM utilities to separate headers

src/win32/PropVariant.cxx

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2020-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "PropVariant.hxx"
+#include "lib/icu/Win32.hxx"
+#include "util/AllocatedString.hxx"
+#include "util/ScopeExit.hxx"
+
+AllocatedString
+ToString(const PROPVARIANT &pv) noexcept
+{
+	// TODO: VT_BSTR
+
+	switch (pv.vt) {
+	case VT_LPSTR:
+		return AllocatedString{static_cast<const char *>(pv.pszVal)};
+
+	case VT_LPWSTR:
+		return WideCharToMultiByte(CP_UTF8, pv.pwszVal);
+
+	default:
+		return nullptr;
+	}
+}

src/win32/PropVariant.hxx

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2020-2021 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_WIN32_PROPVARIANT_HXX
+#define MPD_WIN32_PROPVARIANT_HXX
+
+#include <propidl.h>
+
+class AllocatedString;
+
+[[gnu::pure]]
+AllocatedString
+ToString(const PROPVARIANT &pv) noexcept;
+
+#endif

src/win32/meson.build

@@ -7,6 +7,7 @@ win32 = static_library(
   'win32',
   'ComWorker.cxx',
   'HResult.cxx',
+  'PropVariant.cxx',
   'WinEvent.cxx',
   include_directories: inc,
 )