output/wasapi: split the header

Reduce header dependencies.

src/mixer/plugins/WasapiMixerPlugin.cxx

@@ -17,7 +17,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#include "output/plugins/wasapi/WasapiOutputPlugin.hxx"
+#include "output/plugins/wasapi/ForMixer.hxx"
 #include "mixer/MixerInternal.hxx"
 #include "win32/ComPtr.hxx"
 #include "win32/ComWorker.hxx"

src/output/plugins/wasapi/ForMixer.hxx

@@ -0,0 +1,44 @@
+/*
+ * 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_WASAPI_OUTPUT_FOR_MIXER_HXX
+#define MPD_WASAPI_OUTPUT_FOR_MIXER_HXX
+
+struct IMMDevice;
+struct IAudioClient;
+class AudioOutput;
+class WasapiOutput;
+
+[[gnu::pure]]
+WasapiOutput &
+wasapi_output_downcast(AudioOutput &output) noexcept;
+
+[[gnu::pure]]
+bool
+wasapi_is_exclusive(WasapiOutput &output) noexcept;
+
+[[gnu::pure]]
+IMMDevice *
+wasapi_output_get_device(WasapiOutput &output) noexcept;
+
+[[gnu::pure]]
+IAudioClient *
+wasapi_output_get_client(WasapiOutput &output) noexcept;
+
+#endif

src/output/plugins/wasapi/WasapiOutputPlugin.cxx

@@ -18,6 +18,7 @@
  */
 
 #include "WasapiOutputPlugin.hxx"
+#include "ForMixer.hxx"
 #include "output/OutputAPI.hxx"
 #include "lib/icu/Win32.hxx"
 #include "mixer/MixerList.hxx"

src/output/plugins/wasapi/WasapiOutputPlugin.hxx

@@ -22,25 +22,4 @@
 
 extern const struct AudioOutputPlugin wasapi_output_plugin;
 
-struct IMMDevice;
-struct IAudioClient;
-class AudioOutput;
-class WasapiOutput;
-
-[[gnu::pure]]
-WasapiOutput &
-wasapi_output_downcast(AudioOutput &output) noexcept;
-
-[[gnu::pure]]
-bool
-wasapi_is_exclusive(WasapiOutput &output) noexcept;
-
-[[gnu::pure]]
-IMMDevice *
-wasapi_output_get_device(WasapiOutput &output) noexcept;
-
-[[gnu::pure]]
-IAudioClient *
-wasapi_output_get_client(WasapiOutput &output) noexcept;
-
 #endif