added BI44 protocol and direct derive without checking blockchain history

Author: albertopeam

Sources/Web3Core/KeystoreManager/BIP44.swift

@@ -0,0 +1,34 @@
+//
+//  BIP44.swift
+//  Created by Alberto Penas Amor on 15/12/22.
+//
+
+import Foundation
+
+public protocol BIP44 {
+    /**
+     Derive an `HDNode` based on the provided `path`. The function will throws `BIP44Error.warning` if it was invoked with `warns` as true and the root key doesn't have a previous child with at least one transaction, using false the child node will be derived directly not throwing. This function needs to query the blockchain history when `warns`is true,  so it can throw network errors.
+        
+    - Parameter path: valid BIP32 path.
+    - Parameter warns: true to be warned about following BIP44 standard, false otherwise.
+    - Throws: `BIP44Error.warning` if the child key shouldn't be used according to BIP44 standard.
+    - Returns: an HDNode child key for the provided `path` if it can be created, otherwise nil
+     */
+    func derive(path: String, warns: Bool) async throws -> HDNode?
+}
+
+public enum BIP44Error: Equatable {
+    /// The selected path doesn't fulfill BIP44 standard, you can derive the root key anyway
+    case warning
+}
+
+extension HDNode: BIP44 {
+    public func derive(path: String, warns: Bool = true) async throws -> HDNode? {
+        if warns {
+            // https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki#account-discovery
+            return nil
+        } else {
+            return derive(path: path, derivePrivateKey: true)
+        }
+    }
+}

Tests/web3swiftTests/localTests/BIP44Tests.swift

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+//
+//  BIP44Tests.swift
+//  Created by Alberto Penas Amor on 15/12/22.
+//
+
+import XCTest
+import Web3Core
+@testable import web3swift
+
+final class BIP44Tests: XCTestCase {
+    
+    private let mnemonic = "fruit wave dwarf banana earth journey tattoo true farm silk olive fence"
+
+    func testBIP44DeriveWithoutWarningIfChildNodeHasPreviousChildsWithTransactions() async throws {
+        let seed = try XCTUnwrap(BIP39.seedFromMmemonics(mnemonic, password: ""))
+        let rootNode = try XCTUnwrap(HDNode(seed: seed))
+        
+        let optChildNode = try await rootNode.derive(path: "m/44'/60'/1'/0/1", warns: false)
+        let childNode = try XCTUnwrap(optChildNode)
+                
+        XCTAssertEqual(childNode.publicKey.toHexString(), "03fe5fad1740a0c749c3c976c9b37f337204bf3df1d73d78da282dd365a7d47ad9")
+        XCTAssertEqual(Utilities.publicToAddress(childNode.publicKey)?.address, "0x73C13e421eF367c4F55BBC02a8e2a2b12e82f717")
+    }
+}