MUC: Factor out role change permission check into its own method

I would like to invert this logic so that it checks if the role change
is allowed instead of checking if it is not allowed as it does now, in
order to make it easier to understand.

1 files changed, 27 insertions, 18 deletions

diff --git a/plugins/muc/muc.lib.lua b/plugins/muc/muc.lib.lua
index 9b168e93..2b6a7d76 100644
--- a/plugins/muc/muc.lib.lua
+++ b/plugins/muc/muc.lib.lua
@@ -1368,6 +1368,30 @@ function room_mt:get_role(nick)
 	return occupant and occupant.role or nil;
 end
 
+function room_mt:may_set_role(actor, occupant, role)
+	-- Can't do anything to other owners or admins
+	local occupant_affiliation = self:get_affiliation(occupant.bare_jid);
+	if occupant_affiliation == "owner" or occupant_affiliation == "admin" then
+		return nil, "cancel", "not-allowed";
+	end
+
+	-- If you are trying to give or take moderator role you need to be an owner or admin
+	if occupant.role == "moderator" or role == "moderator" then
+		local actor_affiliation = self:get_affiliation(actor);
+		if actor_affiliation ~= "owner" and actor_affiliation ~= "admin" then
+			return nil, "cancel", "not-allowed";
+		end
+	end
+
+	-- Need to be in the room and a moderator
+	local actor_occupant = self:get_occupant_by_real_jid(actor);
+	if not actor_occupant or actor_occupant.role ~= "moderator" then
+		return nil, "cancel", "not-allowed";
+	end
+
+	return true;
+end
+
 function room_mt:set_role(actor, occupant_jid, role, reason)
 	if not actor then return nil, "modify", "not-acceptable"; end
 
@@ -1382,24 +1406,9 @@ function room_mt:set_role(actor, occupant_jid, role, reason)
 	if actor == true then
 		actor = nil -- So we can pass it safely to 'publicise_occupant_status' below
 	else
-		-- Can't do anything to other owners or admins
-		local occupant_affiliation = self:get_affiliation(occupant.bare_jid);
-		if occupant_affiliation == "owner" or occupant_affiliation == "admin" then
-			return nil, "cancel", "not-allowed";
-		end
-
-		-- If you are trying to give or take moderator role you need to be an owner or admin
-		if occupant.role == "moderator" or role == "moderator" then
-			local actor_affiliation = self:get_affiliation(actor);
-			if actor_affiliation ~= "owner" and actor_affiliation ~= "admin" then
-				return nil, "cancel", "not-allowed";
-			end
-		end
-
-		-- Need to be in the room and a moderator
-		local actor_occupant = self:get_occupant_by_real_jid(actor);
-		if not actor_occupant or actor_occupant.role ~= "moderator" then
-			return nil, "cancel", "not-allowed";
+		local allowed, err, condition = self:may_set_role(actor, occupant, role)
+		if not allowed then
+			return allowed, err, condition;
 		end
 	end