Implement mod communication channels (#6351)

Implement network communication for channels

* Implement ModChannel manager server side to route incoming messages from clients to other clients
* Add signal handler switch on client & ModChannelMgr on client to handle channels
* Add Lua API bindings + client packet sending + unittests
* Implement server message sending
* Add callback from received message handler to Lua API using registration method

3 files changed, 82 insertions, 0 deletions

diff --git a/src/script/cpp_api/CMakeLists.txt b/src/script/cpp_api/CMakeLists.txt
index 4b13356a8..3cfd7709a 100644
--- a/src/script/cpp_api/CMakeLists.txt
+++ b/src/script/cpp_api/CMakeLists.txt
@@ -5,6 +5,7 @@ set(common_SCRIPT_CPP_API_SRCS
 	${CMAKE_CURRENT_SOURCE_DIR}/s_env.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/s_inventory.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/s_item.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/s_modchannels.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/s_node.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/s_nodemeta.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/s_player.cpp
diff --git a/src/script/cpp_api/s_modchannels.cpp b/src/script/cpp_api/s_modchannels.cpp
new file mode 100644
index 000000000..caff3f05e
--- /dev/null
+++ b/src/script/cpp_api/s_modchannels.cpp
@@ -0,0 +1,50 @@
+/*
+Minetest
+Copyright (C) 2017 nerzhul, Loic Blot <loic.blot@unix-experience.fr>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser 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 "s_modchannels.h"
+#include "s_internal.h"
+
+void ScriptApiModChannels::on_modchannel_message(const std::string &channel,
+		const std::string &sender, const std::string &message)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	// Get core.registered_on_generateds
+	lua_getglobal(L, "core");
+	lua_getfield(L, -1, "registered_on_modchannel_message");
+	// Call callbacks
+	lua_pushstring(L, channel.c_str());
+	lua_pushstring(L, sender.c_str());
+	lua_pushstring(L, message.c_str());
+	runCallbacks(3, RUN_CALLBACKS_MODE_AND);
+}
+
+void ScriptApiModChannels::on_modchannel_signal(
+		const std::string &channel, ModChannelSignal signal)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	// Get core.registered_on_generateds
+	lua_getglobal(L, "core");
+	lua_getfield(L, -1, "registered_on_modchannel_signal");
+	// Call callbacks
+	lua_pushstring(L, channel.c_str());
+	lua_pushinteger(L, (int)signal);
+	runCallbacks(2, RUN_CALLBACKS_MODE_AND);
+}
diff --git a/src/script/cpp_api/s_modchannels.h b/src/script/cpp_api/s_modchannels.h
new file mode 100644
index 000000000..4de7a8291
--- /dev/null
+++ b/src/script/cpp_api/s_modchannels.h
@@ -0,0 +1,31 @@
+/*
+Minetest
+Copyright (C) 2017 nerzhul, Loic Blot <loic.blot@unix-experience.fr>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser 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.
+*/
+
+#pragma once
+
+#include "cpp_api/s_base.h"
+#include "modchannels.h"
+
+class ScriptApiModChannels : virtual public ScriptApiBase
+{
+public:
+	void on_modchannel_message(const std::string &channel, const std::string &sender,
+			const std::string &message);
+	void on_modchannel_signal(const std::string &channel, ModChannelSignal signal);
+};