1 files changed, 204 insertions, 0 deletions
diff --git a/src/output/OutputPlugin.hxx b/src/output/OutputPlugin.hxx
new file mode 100644
index 000000000..00fa36bc0
--- /dev/null
+++ b/src/output/OutputPlugin.hxx
@@ -0,0 +1,204 @@
+/*
+ * Copyright (C) 2003-2014 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_OUTPUT_PLUGIN_HXX
+#define MPD_OUTPUT_PLUGIN_HXX
+
+#include "Compiler.h"
+
+#include <stddef.h>
+
+struct config_param;
+struct AudioFormat;
+struct Tag;
+struct AudioOutput;
+struct MixerPlugin;
+class Error;
+
+/**
+ * A plugin which controls an audio output device.
+ */
+struct AudioOutputPlugin {
+	/**
+	 * the plugin's name
+	 */
+	const char *name;
+
+	/**
+	 * Test if this plugin can provide a default output, in case
+	 * none has been configured.  This method is optional.
+	 */
+	bool (*test_default_device)(void);
+
+	/**
+	 * Configure and initialize the device, but do not open it
+	 * yet.
+	 *
+	 * @param param the configuration section, or nullptr if there is
+	 * no configuration
+	 * @return nullptr on error, or an opaque pointer to the plugin's
+	 * data
+	 */
+	AudioOutput *(*init)(const config_param &param,
+				     Error &error);
+
+	/**
+	 * Free resources allocated by this device.
+	 */
+	void (*finish)(AudioOutput *data);
+
+	/**
+	 * Enable the device.  This may allocate resources, preparing
+	 * for the device to be opened.  Enabling a device cannot
+	 * fail: if an error occurs during that, it should be reported
+	 * by the open() method.
+	 *
+	 * @return true on success, false on error
+	 */
+	bool (*enable)(AudioOutput *data, Error &error);
+
+	/**
+	 * Disables the device.  It is closed before this method is
+	 * called.
+	 */
+	void (*disable)(AudioOutput *data);
+
+	/**
+	 * Really open the device.
+	 *
+	 * @param audio_format the audio format in which data is going
+	 * to be delivered; may be modified by the plugin
+	 */
+	bool (*open)(AudioOutput *data, AudioFormat &audio_format,
+		     Error &error);
+
+	/**
+	 * Close the device.
+	 */
+	void (*close)(AudioOutput *data);
+
+	/**
+	 * Returns a positive number if the output thread shall delay
+	 * the next call to play() or pause().  This should be
+	 * implemented instead of doing a sleep inside the plugin,
+	 * because this allows MPD to listen to commands meanwhile.
+	 *
+	 * @return the number of milliseconds to wait
+	 */
+	unsigned (*delay)(AudioOutput *data);
+
+	/**
+	 * Display metadata for the next chunk.  Optional method,
+	 * because not all devices can display metadata.
+	 */
+	void (*send_tag)(AudioOutput *data, const Tag *tag);
+
+	/**
+	 * Play a chunk of audio data.
+	 *
+	 * @return the number of bytes played, or 0 on error
+	 */
+	size_t (*play)(AudioOutput *data,
+		       const void *chunk, size_t size,
+		       Error &error);
+
+	/**
+	 * Wait until the device has finished playing.
+	 */
+	void (*drain)(AudioOutput *data);
+
+	/**
+	 * Try to cancel data which may still be in the device's
+	 * buffers.
+	 */
+	void (*cancel)(AudioOutput *data);
+
+	/**
+	 * Pause the device.  If supported, it may perform a special
+	 * action, which keeps the device open, but does not play
+	 * anything.  Output plugins like "shout" might want to play
+	 * silence during pause, so their clients won't be
+	 * disconnected.  Plugins which do not support pausing will
+	 * simply be closed, and have to be reopened when unpaused.
+	 *
+	 * @return false on error (output will be closed then), true
+	 * for continue to pause
+	 */
+	bool (*pause)(AudioOutput *data);
+
+	/**
+	 * The mixer plugin associated with this output plugin.  This
+	 * may be nullptr if no mixer plugin is implemented.  When
+	 * created, this mixer plugin gets the same #config_param as
+	 * this audio output device.
+	 */
+	const MixerPlugin *mixer_plugin;
+};
+
+static inline bool
+ao_plugin_test_default_device(const AudioOutputPlugin *plugin)
+{
+	return plugin->test_default_device != nullptr
+		? plugin->test_default_device()
+		: false;
+}
+
+gcc_malloc
+AudioOutput *
+ao_plugin_init(const AudioOutputPlugin *plugin,
+	       const config_param &param,
+	       Error &error);
+
+void
+ao_plugin_finish(AudioOutput *ao);
+
+bool
+ao_plugin_enable(AudioOutput *ao, Error &error);
+
+void
+ao_plugin_disable(AudioOutput *ao);
+
+bool
+ao_plugin_open(AudioOutput *ao, AudioFormat &audio_format,
+	       Error &error);
+
+void
+ao_plugin_close(AudioOutput *ao);
+
+gcc_pure
+unsigned
+ao_plugin_delay(AudioOutput *ao);
+
+void
+ao_plugin_send_tag(AudioOutput *ao, const Tag *tag);
+
+size_t
+ao_plugin_play(AudioOutput *ao, const void *chunk, size_t size,
+	       Error &error);
+
+void
+ao_plugin_drain(AudioOutput *ao);
+
+void
+ao_plugin_cancel(AudioOutput *ao);
+
+bool
+ao_plugin_pause(AudioOutput *ao);
+
+#endif