Merge pull request #349 from James-Sangalli/fixFailedParsingOnOldERC875Tokens

guard against new and old tickets in ethereum

Trust/Foundation/XMLHandler.swift

@@ -14,8 +14,7 @@ public class XMLHandler {
 
     private let xml = try! XML.parse(AssetDefinitionXML.assetDefinition)
 
-    private func formatDateToMoscow(_ timestamp: Int) -> Date
-    {
+    private func formatDateToMoscow(_ timestamp: Int) -> Date {
         let formatter = DateFormatter()
         formatter.timeZone = TimeZone(secondsFromGMT: 10800)
         formatter.dateFormat = "dd/MM/yyyy hh:mm:ss a"
@@ -27,6 +26,20 @@ public class XMLHandler {
         return unFormattedDate
     }
 
+    //TODO remove once parser is properly dynamic
+    public static func parseTicket(ticket: String) -> String
+    {
+        let no0xTicket = ticket.substring(from: 2)
+        let firstHalfOfTicket = no0xTicket.substring(to: 32)
+        let bigUIntFirstHalf = BigUInt(firstHalfOfTicket, radix: 16)
+        if bigUIntFirstHalf == 0 {
+            return no0xTicket
+        }
+        //if first 16 bytes are not empty then cut it in half
+        //else return with padded 0's
+        return no0xTicket.substring(from: 32)
+    }
+
     func getFifaInfoForTicket(tokenId tokenBytes32: BigUInt, index: UInt16) -> Ticket {
         //check if leading or trailing zeros
         let tokenId = tokenBytes32
@@ -99,14 +112,17 @@ public class XMLHandler {
 
     func getLocality(attribute: String, lang: Int) -> String {
         //entity keys start at 1 but xml finder starts at 0, hence -1
-        let locality = Int(attribute, radix: 16)! - 1
-        if let parsedLocality = xml["asset"]["fields"]["field"][0][0]["mapping"]["entity"][locality]["name"][lang].text {
+        if let locality = Int(attribute, radix: 16) {
+            guard locality != 0 else { return "N/A" }
+            if let parsedLocality = xml["asset"]["fields"]["field"][0][0]["mapping"]["entity"][locality - 1]["name"][lang].text {
                 return parsedLocality
             }
+        }
         return "N/A"
     }
     
     func getCategory(_ cat: Int, lang: Int) -> String {
+        guard cat != 0 else { return "N/A" }
         if let category = xml["asset"]["fields"]["field"][6][0]["mapping"]["entity"][cat - 1]["name"][lang].text {
             return category
         }
@@ -114,10 +130,12 @@ public class XMLHandler {
     }
 
     func getVenue(attribute: String, lang: Int) -> String {
-        let venueNumber = Int(attribute, radix: 16)! - 1
-        if let parsedVenue = xml["asset"]["fields"]["field"][1][0]["mapping"]["entity"][venueNumber]["name"][lang].text {
+        if let venueNumber = Int(attribute, radix: 16) {
+            guard venueNumber != 0 else { return "N/A" }
+            if let parsedVenue = xml["asset"]["fields"]["field"][1][0]["mapping"]["entity"][venueNumber - 1]["name"][lang].text {
                 return parsedVenue
             }
+        }
         return "N/A"
     }
 

Trust/Tokens/Helpers/TicketAdaptor.swift

@@ -22,12 +22,12 @@ class TicketAdaptor {
         for (index, item) in balance.enumerated() {
             //id is the value of the bytes32 ticket
             let id = item.balance
-            if id == "0x0000000000000000000000000000000000000000000000000000000000000000" { // if balance is 0, then skip
+            if id == Constants.nullTicket { // if balance is 0, then skip
                 continue
             }
             //TODO shouldn't have to do this when parser is dynamic
-            let ticketData = id.substring(from: 2)
-            let ticket = getTicket(for: BigUInt(ticketData.substring(from: 32), radix: 16)!, index: UInt16(index), in: token)
+            let ticketData = XMLHandler.parseTicket(ticket: id)
+            let ticket = getTicket(for: BigUInt(ticketData, radix: 16)!, index: UInt16(index), in: token)
             tickets.append(ticket)
         }