Add erc base properties provider

Author: janndriessen

Sources/web3swift/Utils/ERC/ERCBasePropertiesProvider.swift

@@ -0,0 +1,39 @@
+//
+//  ERCBasePropertiesProvider.swift
+//  
+//
+//  Created by Jann Driessen on 21.11.22.
+//
+
+import BigInt
+import Foundation
+
+public final class ERCBasePropertiesProvider {
+    var name: String?
+    var symbol: String?
+    var decimals: UInt8?
+
+    private let contract: Web3.Contract
+    private (set) var hasReadProperties: Bool = false
+    init(contract: Web3.Contract) {
+        self.contract = contract
+    }
+
+    public func readProperties() async throws {
+        guard !hasReadProperties else { return }
+        guard contract.contract.address != nil else {return}
+        name = try await contract
+            .createReadOperation("name")?
+            .callContractMethod()["0"] as? String
+
+        symbol = try await contract
+            .createReadOperation("symbol")?
+            .callContractMethod()["0"] as? String
+
+        let decimals = try await contract
+            .createReadOperation("decimals")?
+            .callContractMethod()["0"] as? BigUInt
+        self.decimals = decimals != nil ? UInt8(decimals!) : nil
+        hasReadProperties = true
+    }
+}