From 7a68775e6c6ce925b01409c0bc8b2db22e5818ec Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Tue, 23 Feb 2021 22:12:43 +0100
Subject: [PATCH] output/snapcast: Zeroconf support

---
 doc/plugins.rst                               |  3 +++
 meson.build                                   |  3 ++-
 src/output/plugins/meson.build                |  2 +-
 src/output/plugins/snapcast/Internal.hxx      | 11 ++++++++++
 .../plugins/snapcast/SnapcastOutputPlugin.cxx | 21 ++++++++++++++++++-
 5 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/doc/plugins.rst b/doc/plugins.rst
index ec5f000b4..f85692ae4 100644
--- a/doc/plugins.rst
+++ b/doc/plugins.rst
@@ -1167,6 +1167,9 @@ connect to it and receive audio data from MPD.
      - Binds the Snapcast server to the specified address.  Multiple
        addresses in parallel are not supported.  The default is to
        bind on all addresses on port :samp:`1704`.
+   * - **zeroconf yes|no**
+     - Publish the Snapcast server as service type ``_snapcast._tcp``
+       via Zeroconf (Avahi or Bonjour).  Default is :samp:`yes`.
 
 
 solaris
diff --git a/meson.build b/meson.build
index dce9ca2ea..e9e95a7e1 100644
--- a/meson.build
+++ b/meson.build
@@ -369,6 +369,8 @@ subdir('src/lib/yajl')
 
 subdir('src/lib/crypto')
 
+subdir('src/zeroconf')
+
 subdir('src/fs')
 subdir('src/config')
 subdir('src/tag')
@@ -384,7 +386,6 @@ subdir('src/decoder')
 subdir('src/encoder')
 subdir('src/song')
 subdir('src/playlist')
-subdir('src/zeroconf')
 
 if curl_dep.found()
   sources += 'src/RemoteTagCache.cxx'
diff --git a/src/output/plugins/meson.build b/src/output/plugins/meson.build
index 71b8bb55f..d0810fc47 100644
--- a/src/output/plugins/meson.build
+++ b/src/output/plugins/meson.build
@@ -119,7 +119,7 @@ if get_option('snapcast')
     'snapcast/SnapcastOutputPlugin.cxx',
     'snapcast/Client.cxx',
   ]
-  output_plugins_deps += [ event_dep, net_dep, yajl_dep ]
+  output_plugins_deps += [ event_dep, net_dep, yajl_dep, zeroconf_dep ]
 
   output_features.set('HAVE_YAJL', yajl_dep.found())
 
diff --git a/src/output/plugins/snapcast/Internal.hxx b/src/output/plugins/snapcast/Internal.hxx
index 291dc378c..33fc85b26 100644
--- a/src/output/plugins/snapcast/Internal.hxx
+++ b/src/output/plugins/snapcast/Internal.hxx
@@ -30,14 +30,21 @@
 #include "util/AllocatedArray.hxx"
 #include "util/IntrusiveList.hxx"
 
+#include "config.h" // for HAVE_ZEROCONF
+
 #include <memory>
 
 struct ConfigBlock;
 class SnapcastClient;
 class PreparedEncoder;
 class Encoder;
+class ZeroconfHelper;
 
 class SnapcastOutput final : AudioOutput, ServerSocket {
+#ifdef HAVE_ZEROCONF
+	unsigned zeroconf_port = 0;
+#endif
+
 	/**
 	 * True if the audio output is open and accepts client
 	 * connections.
@@ -46,6 +53,10 @@ class SnapcastOutput final : AudioOutput, ServerSocket {
 
 	InjectEvent inject_event;
 
+#ifdef HAVE_ZEROCONF
+	std::unique_ptr<ZeroconfHelper> zeroconf_helper;
+#endif
+
 	/**
 	 * The configured encoder plugin.
 	 */
diff --git a/src/output/plugins/snapcast/SnapcastOutputPlugin.cxx b/src/output/plugins/snapcast/SnapcastOutputPlugin.cxx
index 3face3a91..c62343471 100644
--- a/src/output/plugins/snapcast/SnapcastOutputPlugin.cxx
+++ b/src/output/plugins/snapcast/SnapcastOutputPlugin.cxx
@@ -32,6 +32,10 @@
 #include "util/DeleteDisposer.hxx"
 #include "config/Net.hxx"
 
+#ifdef HAVE_ZEROCONF
+#include "zeroconf/Helper.hxx"
+#endif
+
 #ifdef HAVE_YAJL
 #include "lib/yajl/Gen.hxx"
 #endif
@@ -49,8 +53,14 @@ SnapcastOutput::SnapcastOutput(EventLoop &_loop, const ConfigBlock &block)
 	 // TODO: support other encoder plugins?
 	 prepared_encoder(encoder_init(wave_encoder_plugin, block))
 {
+	const unsigned port = block.GetBlockValue("port", 1704U);
 	ServerSocketAddGeneric(*this, block.GetBlockValue("bind_to_address"),
-			       block.GetBlockValue("port", 1704U));
+			       port);
+
+#ifdef HAVE_ZEROCONF
+	if (block.GetBlockValue("zeroconf", true))
+		zeroconf_port = port;
+#endif
 }
 
 SnapcastOutput::~SnapcastOutput() noexcept = default;
@@ -62,6 +72,13 @@ SnapcastOutput::Bind()
 
 	BlockingCall(GetEventLoop(), [this](){
 		ServerSocket::Open();
+
+#ifdef HAVE_ZEROCONF
+		if (zeroconf_port > 0)
+			zeroconf_helper = std::make_unique<ZeroconfHelper>
+				(GetEventLoop(), "Music Player Daemon",
+				 "_snapcast._tcp", zeroconf_port);
+#endif
 	});
 
 	// TODO: Zeroconf integration
@@ -73,6 +90,8 @@ SnapcastOutput::Unbind() noexcept
 	assert(!open);
 
 	BlockingCall(GetEventLoop(), [this](){
+		zeroconf_helper.reset();
+
 		ServerSocket::Close();
 	});
 }