Detect invalid menu item selections in L4D-based games (#1543)

Some games have implemented CHudMenu::SelectMenuItem to close the menu
even if an invalid slot has been selected, which causes us a problem as
we'll never get any notification from the client and we'll keep the menu
alive on our end indefinitely. For these games, pretend that every slot
is valid for selection so we're guaranteed to get a menuselect command.
We don't want to do this for every game as the common SelectMenuItem
implementation ignores invalid selections and keeps the menu open, which
is a much nicer user experience.

Fixes #1385

core/MenuStyle_Radio.cpp

@@ -61,7 +61,7 @@ unsigned int g_RadioMenuTimeout = 0;
 #define MAX_MENUSLOT_KEYS 10
 
 static unsigned int s_RadioMaxPageItems = MAX_MENUSLOT_KEYS;
-
+static bool s_RadioClosesOnInvalidSlot = false;
 
 CRadioStyle::CRadioStyle()
 {
@@ -124,6 +124,12 @@ void CRadioStyle::OnSourceModLevelChange(const char *mapName)
 		}
 	}
 
+	const char *closes = g_pGameConf->GetKeyValue("RadioMenuClosesOnInvalidSlot");
+	if (closes != nullptr && strcmp(closes, "yes") == 0)
+	{
+		s_RadioClosesOnInvalidSlot = true;
+	}
+
 	g_Menus.SetDefaultStyle(this);
 
 	g_UserMsgs.HookUserMessage(g_ShowMenuId, this, false);
@@ -464,7 +470,16 @@ void CRadioMenuPlayer::Radio_Init(int keys, const char *title, const char *text)
 			sizeof(display_pkt), 
 			text);
 	}
-	display_keys = keys;
+
+	// Some games have implemented CHudMenu::SelectMenuItem to close the menu
+	// even if an invalid slot has been selected, which causes us a problem as
+	// we'll never get any notification from the client and we'll keep the menu
+	// alive on our end indefinitely. For these games, pretend that every slot
+	// is valid for selection so we're guaranteed to get a menuselect command.
+	// We don't want to do this for every game as the common SelectMenuItem
+	// implementation ignores invalid selections and keeps the menu open, which
+	// is a much nicer user experience.
+	display_keys = s_RadioClosesOnInvalidSlot ? 0x7ff : keys;
 }
 
 void CRadioMenuPlayer::Radio_Refresh()

gamedata/core.games/common.games.txt

@@ -197,7 +197,7 @@
 		}
 	}
 
-		"#default"
+	"#default"
 	{
 		"#supported"
 		{
@@ -366,4 +366,19 @@
 			"RadioMenuMaxPageItems"	"6"
 		}
 	}
+
+	"#default"
+	{
+		"#supported"
+		{
+			"engine"	"left4dead"
+			"engine"	"left4dead2"
+			"engine"	"nucleardawn"
+		}
+
+		"Keys"
+		{
+			"RadioMenuClosesOnInvalidSlot"	"yes"
+		}
+	}
 }