Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/UIKit/Sources/UIImagePickerController+Promise.swift

@@ -0,0 +1,80 @@
+#if !PMKCocoaPods
+import PromiseKit
+#endif
+import UIKit
+
+#if !os(tvOS)
+
+extension UIViewController {
+#if swift(>=4.2)
+    /// Presents the UIImagePickerController, resolving with the user action.
+    public func promise(_ vc: UIImagePickerController, animate: PMKAnimationOptions = [.appear, .disappear], completion: (() -> Void)? = nil) -> Promise<[UIImagePickerController.InfoKey: Any]> {
+        let animated = animate.contains(.appear)
+        let proxy = UIImagePickerControllerProxy()
+        vc.delegate = proxy
+        present(vc, animated: animated, completion: completion)
+        return proxy.promise.ensure {
+            vc.presentingViewController?.dismiss(animated: animated, completion: nil)
+        }
+    }
+#else
+    /// Presents the UIImagePickerController, resolving with the user action.
+    public func promise(_ vc: UIImagePickerController, animate: PMKAnimationOptions = [.appear, .disappear], completion: (() -> Void)? = nil) -> Promise<[String: Any]> {
+        let animated = animate.contains(.appear)
+        let proxy = UIImagePickerControllerProxy()
+        vc.delegate = proxy
+        present(vc, animated: animated, completion: completion)
+        return proxy.promise.ensure {
+            vc.presentingViewController?.dismiss(animated: animated, completion: nil)
+        }
+    }
+#endif
+}
+
+@objc private class UIImagePickerControllerProxy: NSObject, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
+#if swift(>=4.2)
+    let (promise, seal) = Promise<[UIImagePickerController.InfoKey: Any]>.pending()
+#else
+    let (promise, seal) = Promise<[String: Any]>.pending()
+#endif
+    var retainCycle: AnyObject?
+
+    required override init() {
+        super.init()
+        retainCycle = self
+    }
+
+#if swift(>=4.2)
+    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey: Any]) {
+        seal.fulfill(info)
+        retainCycle = nil
+    }
+#else
+    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String: Any]) {
+        seal.fulfill(info)
+        retainCycle = nil
+    }
+#endif
+
+    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
+        seal.reject(UIImagePickerController.PMKError.cancelled)
+        retainCycle = nil
+    }
+}
+
+extension UIImagePickerController {
+    /// Errors representing PromiseKit UIImagePickerController failures
+    public enum PMKError: CancellableError {
+        /// The user cancelled the UIImagePickerController.
+        case cancelled
+        /// - Returns: true
+        public var isCancelled: Bool {
+            switch self {
+            case .cancelled:
+                return true
+            }
+        }
+    }
+}
+
+#endif