addresses feedback

packages/url_launcher/url_launcher_ios/example/ios/RunnerTests/URLLauncherTests.swift

@@ -41,10 +41,10 @@ final class URLLauncherTests: XCTestCase {
       let result = try createPlugin().canLaunchUrl(url: "urls can't have spaces")
       XCTAssertFalse(result)
     } catch {
-      let generalError = error as? GeneralError
+      let generalError = error as? FlutterError
       XCTAssertEqual(generalError?.code, "argument_error")
       XCTAssertEqual(generalError?.message, "Unable to parse URL")
-      XCTAssertEqual(generalError?.details, "Provided URL: urls can't have spaces")
+      XCTAssertEqual(generalError?.details as? String, "Provided URL: urls can't have spaces")
     }
   }
 
@@ -89,10 +89,10 @@ final class URLLauncherTests: XCTestCase {
       case .failure(let error):
         XCTAssertNotNil(error)
 
-        let generalError = error as! GeneralError
-        XCTAssertEqual(generalError.code, "argument_error")
-        XCTAssertEqual(generalError.message, "Unable to parse URL")
-        XCTAssertEqual(generalError.details, "Provided URL: urls can't have spaces")
+        let generalError = error as? FlutterError
+        XCTAssertEqual(generalError?.code, "argument_error")
+        XCTAssertEqual(generalError?.message, "Unable to parse URL")
+        XCTAssertEqual(generalError?.details as? String, "Provided URL: urls can't have spaces")
       }
       expectation.fulfill()
     }

packages/url_launcher/url_launcher_ios/ios/Classes/Launcher.swift

@@ -2,13 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/// Protocol for UIApplication methods relating to launching URLs.
+///
+/// This protocol exists to allow injecting an alternate implementation for testing.
 protocol Launcher {
   func canOpenURL(_ url: URL) -> Bool
   func openURL(
     _ url: URL, options: [UIApplication.OpenExternalURLOptionsKey: Any],
     completionHandler completion: ((Bool) -> Void)?)
 }
 
+/// Default implementation of Launcher, using UIApplication.
 final class UIApplicationLauncher: Launcher {
   func canOpenURL(_ url: URL) -> Bool {
     UIApplication.shared.canOpenURL(url)

packages/url_launcher/url_launcher_ios/ios/Classes/URLLaunchSession.swift

@@ -2,34 +2,36 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import Flutter
 import SafariServices
 
-typealias OpenInSafariVCResponse = (Result<Bool, Error>) -> Void
+typealias OpenInSafariCompletionHandler = (Result<Bool, Error>) -> Void
 
 final class URLLaunchSession: NSObject, SFSafariViewControllerDelegate {
 
-  private let completion: OpenInSafariVCResponse
+  private let completion: OpenInSafariCompletionHandler
   private let url: URL
-  let safari: SFSafariViewController
+  let safariViewController: SFSafariViewController
   var didFinish: (() -> Void)?
 
-  init(url: URL, completion: @escaping OpenInSafariVCResponse) {
+  init(url: URL, completion: @escaping OpenInSafariCompletionHandler) {
     self.url = url
     self.completion = completion
-    self.safari = SFSafariViewController(url: url)
+    self.safariViewController = SFSafariViewController(url: url)
     super.init()
-    self.safari.delegate = self
+    self.safariViewController.delegate = self
   }
 
   func safariViewController(
     _ controller: SFSafariViewController, didCompleteInitialLoad didLoadSuccessfully: Bool
   ) {
     if didLoadSuccessfully {
-      completion(Result.success(true))
+      completion(.success(true))
     } else {
       completion(
-        Result.failure(
-          GeneralError(code: "Error", message: "Error while launching \(url)", details: nil)))
+        .failure(
+          FlutterError(code: "Error", message: "Error while launching \(url)", details: nil))
+      )
     }
   }
 
@@ -39,6 +41,6 @@ final class URLLaunchSession: NSObject, SFSafariViewControllerDelegate {
   }
 
   func close() {
-    safariViewControllerDidFinish(safari)
+    safariViewControllerDidFinish(safariViewController)
   }
 }

packages/url_launcher/url_launcher_ios/ios/Classes/URLLauncherPlugin.swift

@@ -15,6 +15,12 @@ public final class URLLauncherPlugin: NSObject, FlutterPlugin, UrlLauncherApi {
   private var currentSession: URLLaunchSession?
   private let launcher: Launcher
 
+  var topViewController: UIViewController? {
+    // TODO(stuartmorgan) Provide a non-deprecated codepath. See
+    // https://github.com/flutter/flutter/issues/104117
+    UIApplication.shared.keyWindow?.rootViewController?.topViewController
+  }
+
   init(launcher: Launcher = UIApplicationLauncher()) {
     self.launcher = launcher
   }
@@ -47,39 +53,33 @@ public final class URLLauncherPlugin: NSObject, FlutterPlugin, UrlLauncherApi {
       return
     }
 
-    currentSession = URLLaunchSession(url: url, completion: completion)
-    guard let session = currentSession else { return }
+    let session = URLLaunchSession(url: url, completion: completion)
+    currentSession = session
 
     session.didFinish = { [weak self] in
       self?.currentSession = nil
     }
-    topViewController?.present(session.safari, animated: true, completion: nil)
+    topViewController?.present(session.safariViewController, animated: true, completion: nil)
   }
 
   func closeSafariViewController() throws {
     currentSession?.close()
   }
 
-  var topViewController: UIViewController? {
-    // TODO(stuartmorgan) Provide a non-deprecated codepath. See
-    // https://github.com/flutter/flutter/issues/104117
-    UIApplication.shared.keyWindow?.rootViewController?.topViewController
-  }
-
   /**
     * Creates an error for an invalid URL string.
     *
     * @param url The invalid URL string
     * @return The error to return
     */
   func invalidURLError(for url: String) -> Error {
-    GeneralError(
+    FlutterError(
       code: "argument_error", message: "Unable to parse URL", details: "Provided URL: \(url)")
   }
 }
 
-/// This method recursively iterate through the view hierarchy
-/// to return the top most view controller.
+/// This method recursively iterates through the view hierarchy
+/// to return the top-most view controller.
 ///
 /// It supports the following scenarios:
 ///
@@ -104,14 +104,4 @@ extension UIViewController {
   }
 }
 
-class GeneralError: Error {
-  let code: String
-  let message: String
-  let details: String?
-
-  init(code: String, message: String, details: String? = nil) {
-    self.code = code
-    self.message = message
-    self.details = details
-  }
-}
+extension FlutterError: Error {}