minor refactor

SessionMessagingKit/Messages/Message.swift

@@ -68,6 +68,21 @@ public class Message: Codable {
         preconditionFailure("toProto(_:) is abstract and must be overridden.")
     }
     
+    public func setDisappearingMessagesConfigurationIfNeeded(_ db: Database, on proto: SNProtoContent.SNProtoContentBuilder) throws {
+        guard
+            let threadId: String = threadId,
+            let disappearingMessagesConfiguration = try? DisappearingMessagesConfiguration.fetchOne(db, id: threadId)
+        else { return }
+        
+        proto.setExpirationTimer(UInt32(disappearingMessagesConfiguration.durationSeconds))
+        
+        if disappearingMessagesConfiguration.isEnabled,
+            let type = disappearingMessagesConfiguration.type
+        {
+            proto.setExpirationType(type.toProto())
+        }
+    }
+
     public func setGroupContextIfNeeded(_ db: Database, on dataMessage: SNProtoDataMessage.SNProtoDataMessageBuilder) throws {
         guard
             let threadId: String = threadId,

SessionMessagingKit/Messages/Visible Messages/VisibleMessage.swift

@@ -184,16 +184,11 @@ public final class VisibleMessage: Message {
         }
         
         // DisappearingMessagesConfiguration
-        if let threadId = self.threadId,
+        do {
-            let disappearingMessagesConfiguration = try? DisappearingMessagesConfiguration.fetchOne(db, id: threadId)
+            try setDisappearingMessagesConfigurationIfNeeded(db, on: proto)
-        {
+        } catch {
-            proto.setExpirationTimer(UInt32(disappearingMessagesConfiguration.durationSeconds))
+            SNLog("Couldn't construct visible message proto from: \(self).")
-            
+            return nil
-            if disappearingMessagesConfiguration.isEnabled,
-                let type = disappearingMessagesConfiguration.type
-            {
-                proto.setExpirationType(type.toProto())
-            }
         }
         
         // Group context