Hi, I've a project that uses both Objective-C and Swift code. When a user logs in, it calls a set of apis for user preference, I have a DataCoordinator.swift class which schedules the API operation and I make this calls from UserDetailViewController.m class to load user preferences, so the main user dashboard loads only when all the api calls are complete and this class also help prevent multiple api calls. This use to work fine before I migrated my code to Swift 4 using Xcode 9 beta 4. Now when I login it crashes by giving me this error in my DataCoordinator class. Below is a sample of my DataCoordinator and UserDetailViewController class.
DataCoordinator.swiftimport UIKit
@objcMembers
class DataCoordinator: NSObject {
fileprivate var user = myDataStore.sharedInstance().user
fileprivate var preferenceFetchOperations = [FetchOperation]()
fileprivate func scheduleFetchOperation(_ operation:FetchOperation, inFetchOperations operations:inout [FetchOperation]) {
guard operations.index(of: operation) == nil else { return }
operations.append(operation)
}
fileprivate func completeFetchOperation(_ fetchOperation:FetchOperation, withError error:Error?, andCompletionHandler handler:@escaping FetchCompletionHandler) {
func removeOperation(_ operation:FetchOperation, fromOperations operations:inout [FetchOperation]) {
if operations.count > 0 {
operations.remove(at: operations.index(of: fetchOperation)!)
handler(error)
}
}
if preferenceFetchOperations.contains(fetchOperation) {
removeOperation(fetchOperation, fromOperations: &preferenceFetchOperations)
}
}
fileprivate func schedulePreferencesFetchOperation(_ serviceName:String, fetch:@escaping FetchOperationBlock){
let operation = FetchOperation(name: serviceName, fetch: fetch);
scheduleFetchOperation(operation, inFetchOperations: &preferenceFetchOperations)
}
fileprivate func runOperationsIn(_ fetchOperations:inout [FetchOperation]) {
for var operation in fetchOperations {
guard operation.isActivated == false else { continue }
operation.isActivated = true
operation.execute()
}
}
typealias FetchCompletionHandler = (_ error:Error?)->Void
var numberOfPreferencesFetchCalls:Int {
get { return preferenceFetchOperations.count }
}
func fetchPreferences(_ completionHandler:@escaping FetchCompletionHandler) -> Void {
defer {
runOperationsIn(&preferenceFetchOperations)
}
schedulePreferencesFetchOperation("com.fetchPreferences.type1") {[unowned self] (operation:FetchOperation) in
WebServiceManager.getType1Detail(for: user) {[unowned self] (error) in
self.completeFetchOperation(operation, withError: error, andCompletionHandler: completionHandler)
}
}
schedulePreferencesFetchOperation("com.fetchPreferences.type2") {[unowned self] (operation:FetchOperation) in
WebServiceManager.getType2Detail(for: user) {[unowned self] (error) in
self.completeFetchOperation(operation, withError: error, andCompletionHandler: completionHandler)
}
}
schedulePreferencesFetchOperation("com.fetchPreferences.type3") {[unowned self] (operation:FetchOperation) in
WebServiceManager.getType3Detail(for: user) {[unowned self] (error) in
self.completeFetchOperation(operation, withError: error, andCompletionHandler: completionHandler)
}
}
schedulePreferencesFetchOperation("com.fetchPreferences.type4") {[unowned self] (operation:FetchOperation) in
WebServiceManager.getType4Detail(for: user) {[unowned self] (error) in
self.completeFetchOperation(operation, withError: error, andCompletionHandler: completionHandler)
}
}
}
}
//Fetch Operation Struct
private typealias FetchOperationBlock = (_ operation:FetchOperation)->Void
private struct FetchOperation:Hashable {
fileprivate var runToken = 0
fileprivate let fetchBlock:FetchOperationBlock
let name:String!
var isActivated:Bool {
get {
return runToken == 0 ? false : true
}
mutating set {
if runToken == 0 && newValue == true {
runToken = 1
}
}
}
fileprivate var hashValue: Int {
get {
return name.hashValue
}
}
func execute() -> Void {
fetchBlock(self)
}
init (name:String, fetch:@escaping FetchOperationBlock) {
self.name = name
self.fetchBlock = fetch
}
}
private func ==(lhs: FetchOperation, rhs: FetchOperation) -> Bool {
return lhs.hashValue == rhs.hashValue
}This is how I use it on my UserDetailViewController class
- (void)viewDidLoad {
[super viewDidLoad];
__weak UserDetailViewController *weakSelf = self;
[self.dataCoordinator fetchPreferences:^(NSError * _Nullable error) {
if (error == nil) {
[weakSelf didFetchPrefrences];
}
else {
//handles error
}
}];
}
//Completion response
- (void)didFetchPrefrences {
//When all api calls completes this will be true
if (self.dataCoordinator.numberOfPreferencesFetchCalls == 0) {
/ /Load details here
}
}Can anyone tell me, how should I proceed on this and modify my DataCoordinator.swift class to support multiple api request without causing this error on Swift 4?
