input data decoding without method name

Author: Alex Vlasov

web3swift/Contract/Classes/Contract.swift

@@ -11,6 +11,7 @@ import BigInt
 
 @available(*, deprecated)
 public struct Contract:ContractProtocol {
+    
     public var allEvents: [String] {
         return events.keys.flatMap({ (s) -> String in
             return s
@@ -210,4 +211,8 @@ public struct Contract:ContractProtocol {
     public func decodeInputData(_ method: String, data: Data) -> [String : Any]? {
         return nil
     }
+    
+    public func decodeInputData(_ data: Data) -> [String : Any]? {
+        return nil
+    }
 }

web3swift/Contract/Classes/ContractABIv2.swift

@@ -232,7 +232,7 @@ public struct ContractV2:ContractProtocol {
 
     public func decodeInputData(_ method: String, data: Data) -> [String : Any]? {
         if method == "fallback" {
-            return [String:Any]()
+            return nil
         }
         guard let function = methods[method] else {return nil}
         switch function {
@@ -241,7 +241,25 @@ public struct ContractV2:ContractProtocol {
         case .constructor(_):
             return function.decodeInputData(data)
         default:
-            return [String:Any]()
+            return nil
+        }
+    }
+    
+    public func decodeInputData(_ data: Data) -> [String:Any]? {
+        guard data.count % 32 == 4 else {return nil}
+        let methodSignature = data[0..<4]
+        let foundFunction = self._abi.filter { (m) -> Bool in
+            switch m {
+            case .function(let function):
+                return function.methodEncoding == methodSignature
+            default:
+                return false
+            }
+        }
+        guard foundFunction.count == 1 else {
+            return nil
         }
+        let function = foundFunction[0]
+        return function.decodeInputData(Data(data[4 ..< data.count]))
     }
 }

web3swift/Contract/Classes/ContractProtocol.swift

@@ -19,6 +19,7 @@ public protocol ContractProtocol {
     init?(_ abiString: String, at: EthereumAddress?)
     func decodeReturnData(_ method:String, data: Data) -> [String:Any]?
     func decodeInputData(_ method:String, data: Data) -> [String:Any]?
+    func decodeInputData(_ data: Data) -> [String:Any]?
     func parseEvent(_ eventLog: EventLog) -> (eventName:String?, eventData:[String:Any]?)
     func testBloomForEventPrecence(eventName: String, bloom: EthereumBloomFilter) -> Bool?
 //    func allEvents() -> [String: [String: Any]?]

web3swiftTests/web3swiftTests.swift

@@ -2148,6 +2148,13 @@ class web3swiftTests: XCTestCase {
         XCTAssert(decoded!["_to"] as? EthereumAddress == EthereumAddress("0xcdd45864e794fe5e3e1b0045b77e62f4c43b8bd9"))
     }
 
+    func testDecodeInputDataWithoutMethodName() {
+        let contract = ContractV2.init(Web3.Utils.erc20ABI)!
+        let dataToDecode = Data.fromHex("0xa9059cbb000000000000000000000000cdd45864e794fe5e3e1b0045b77e62f4c43b8bd9000000000000000000000000000000000000000000000224b5f018c3e30142d5")!
+        let decoded = contract.decodeInputData(dataToDecode)
+        XCTAssert(decoded!["_to"] as? EthereumAddress == EthereumAddress("0xcdd45864e794fe5e3e1b0045b77e62f4c43b8bd9"))
+    }
+    
     func testPerformanceExample() {
         // This is an example of a performance test case.
         self.measure {