Add a "simulate lobby activity" plugin

This is the first step towards creating artificial load and testing if the
GUI2 lobby still performs well under load.

I also implemented ability to leave the game in the GUI2 MP staging dialog.
Previously the server continued to believe that the player remains in the
game when he/she closed the MP staging dialog.

simulate-lobby-activity.lua

@@ -0,0 +1,74 @@
+-- simulate-lobby-activity.lua --
+-- Goes to the MP lobby and chats and creates and leaves games forever. --
+
+local function create_game(context)
+  local events, info
+
+  context.create({})
+
+  repeat
+    events, context, info = coroutine.yield()
+  until info.name == "Multiplayer Create"
+
+  context.select_type({type = "scenario"})
+  local s = info.find_level({id = "test1"})
+  context.select_level({index = s.index})
+  context.set_name({name = tostring(math.random(999999))})
+  context.update_settings({registered_users = false})
+
+  events, context, info = coroutine.yield()
+
+  context.create({})
+end
+
+return function()
+  local events, context, info
+
+  wesnoth.preferences.new_lobby = true
+
+  repeat
+    events, context, info = coroutine.yield()
+  until info.name == "titlescreen" or info.name == "Multiplayer Lobby"
+
+  while info.name == "titlescreen" do
+    context.play_multiplayer({})
+    events, context, info = coroutine.yield()
+  end
+
+  repeat
+    events, context, info = coroutine.yield()
+  until info.name == "Multiplayer Lobby"
+
+  -- Reached the lobby. Random delay before we start actually simulating activity.
+  -- This is here to avoid a situation where activity arrives in bursts after a script
+  -- has launched, say, 100 copies of Wesnoth at the same time.
+  wesnoth.delay(math.random(15000))
+
+  events, context, info = coroutine.yield()
+
+  local in_staging = false
+
+  while true do
+    if math.random() > 0.1 then
+      -- chat message
+      local messages = {"asdf", "qwerty", "zxc"}
+      context.chat({message = messages[math.random(#messages)]})
+    else
+      -- toggle between creating a game and leaving it
+      if not in_staging then
+        create_game(context)
+        in_staging = true
+      else
+        repeat
+          context.quit({})
+          events, context, info = coroutine.yield()
+        until info.name == "Multiplayer Lobby"
+        in_staging = false
+      end
+    end
+
+    wesnoth.delay(15000)
+
+    events, context, info = coroutine.yield()
+  end
+end

src/game_initialization/connect_engine.cpp

@@ -609,6 +609,13 @@ void connect_engine::start_game_commandline(
 	send_to_server(config("start_game"));
 }
 
+void connect_engine::leave_game()
+{
+	DBG_MP << "leaving the game" << std::endl;
+
+	send_to_server(config("leave_game"));
+}
+
 std::pair<bool, bool> connect_engine::process_network_data(const config& data)
 {
 	std::pair<bool, bool> result(std::make_pair(false, true));

src/game_initialization/connect_engine.hpp

@@ -71,6 +71,8 @@ public:
 	void start_game();
 	void start_game_commandline(const commandline_options& cmdline_opts);
 
+	void leave_game();
+
 	// Return pair first element specifies whether to leave the game
 	// and second element whether to silently update UI.
 	std::pair<bool, bool> process_network_data(const config& data);

src/gui/dialogs/multiplayer/mp_staging.cpp

@@ -363,6 +363,9 @@ void tmp_staging::post_show(twindow& window)
 	if(window.get_retval() == twindow::OK) {
 		connect_engine_.start_game();
 	}
+	else {
+		connect_engine_.leave_game();
+	}
 }
 
 } // namespace gui2

src/scripting/application_lua_kernel.cpp

@@ -49,12 +49,12 @@
 
 #include "utils/functional.hpp"
 #include <boost/range/adaptors.hpp>
+#include "video.hpp"
 
 #include "lua/lauxlib.h"
 #include "lua/lua.h"
 #include "lua/luaconf.h"
 
-class CVideo;
 struct lua_State;
 
 static lg::log_domain log_scripting_lua("scripting/lua");
@@ -90,9 +90,22 @@ static int intf_describe_plugins(lua_State * L)
 	return 0;
 }
 
+static int intf_delay(lua_State* L)
+{
+	unsigned int delay = static_cast<unsigned int>(luaL_checkint(L, 1));
+	CVideo::delay(delay);
+	return 0;
+}
+
 application_lua_kernel::application_lua_kernel(CVideo * ptr)
  : lua_kernel_base(ptr)
 {
+	lua_getglobal(mState, "wesnoth");
+	lua_pushcfunction(mState, intf_delay);
+	lua_setfield(mState, -2, "delay");
+
+	lua_settop(mState, 0);
+
 	lua_pushcfunction(mState, &intf_describe_plugins);
 	lua_setglobal(mState, "describe_plugins");
 	lua_settop(mState, 0);