fix: alerts could freeze the application (apache#1437)

Closes apacheGH-1120.
Closes apacheGH-1121.
Closes apacheGH-1429.

Author: dpogue

CordovaLib/Classes/Private/Plugins/CDVWebViewEngine/CDVWebViewEngine.m

@@ -192,7 +192,8 @@ - (void)pluginInitialize
         self.CDV_ASSETS_URL = [NSString stringWithFormat:@"%@://%@", scheme, hostname];
     }
 
-    CDVWebViewUIDelegate* uiDelegate = [[CDVWebViewUIDelegate alloc] initWithTitle:[[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"]];
+    CDVWebViewUIDelegate* uiDelegate = [[CDVWebViewUIDelegate alloc] initWithViewController:vc];
+    uiDelegate.title = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"];
     uiDelegate.allowNewWindows = [settings cordovaBoolSettingForKey:@"AllowNewWindows" defaultValue:NO];
     self.uiDelegate = uiDelegate;
 

CordovaLib/Classes/Private/Plugins/CDVWebViewEngine/CDVWebViewUIDelegate.h

@@ -19,14 +19,24 @@
 
 #import <WebKit/WebKit.h>
 
+#ifdef NS_SWIFT_UI_ACTOR
+#define CDV_SWIFT_UI_ACTOR NS_SWIFT_UI_ACTOR
+#else
+#define CDV_SWIFT_UI_ACTOR
+#endif
+
+@class CDVViewController;
+
+NS_ASSUME_NONNULL_BEGIN
+
+CDV_SWIFT_UI_ACTOR
 @interface CDVWebViewUIDelegate : NSObject <WKUIDelegate>
-{
-    NSMutableArray<UIViewController*>* windows;
-}
 
-@property (nonatomic, copy) NSString* title;
+@property (nonatomic, nullable, copy) NSString* title;
 @property (nonatomic, assign) BOOL allowNewWindows;
 
-- (instancetype)initWithTitle:(NSString*)title;
+- (instancetype)initWithViewController:(CDVViewController*)vc;
 
 @end
+
+NS_ASSUME_NONNULL_END

CordovaLib/Classes/Private/Plugins/CDVWebViewEngine/CDVWebViewUIDelegate.m

@@ -18,22 +18,32 @@ Licensed to the Apache Software Foundation (ASF) under one
  */
 
 #import "CDVWebViewUIDelegate.h"
+#import <Cordova/CDVViewController.h>
+
+@interface CDVWebViewUIDelegate ()
+
+@property (nonatomic, weak) CDVViewController *viewController;
+
+@end
 
 @implementation CDVWebViewUIDelegate
+{
+    NSMutableArray<UIViewController *> *windows;
+}
 
-- (instancetype)initWithTitle:(NSString*)title
+- (instancetype)initWithViewController:(CDVViewController *)vc
 {
     self = [super init];
+
     if (self) {
-        self.title = title;
+        self.viewController = vc;
+        self.title = vc.title;
         windows = [[NSMutableArray alloc] init];
     }
-
     return self;
 }
 
-- (void)     webView:(WKWebView*)webView runJavaScriptAlertPanelWithMessage:(NSString*)message
-    initiatedByFrame:(WKFrameInfo*)frame completionHandler:(void (^)(void))completionHandler
+- (void)webView:(WKWebView*)webView runJavaScriptAlertPanelWithMessage:(NSString*)message initiatedByFrame:(WKFrameInfo*)frame completionHandler:(CDV_SWIFT_UI_ACTOR void (^)(void))completionHandler
 {
     UIAlertController* alert = [UIAlertController alertControllerWithTitle:self.title
                                                                    message:message
@@ -49,13 +59,10 @@ - (void)     webView:(WKWebView*)webView runJavaScriptAlertPanelWithMessage:(NSS
 
     [alert addAction:ok];
 
-    UIViewController* rootController = [UIApplication sharedApplication].delegate.window.rootViewController;
-
-    [rootController presentViewController:alert animated:YES completion:nil];
+    [[self topViewController] presentViewController:alert animated:YES completion:nil];
 }
 
-- (void)     webView:(WKWebView*)webView runJavaScriptConfirmPanelWithMessage:(NSString*)message
-    initiatedByFrame:(WKFrameInfo*)frame completionHandler:(void (^)(BOOL result))completionHandler
+- (void)webView:(WKWebView*)webView runJavaScriptConfirmPanelWithMessage:(NSString*)message initiatedByFrame:(WKFrameInfo*)frame completionHandler:(CDV_SWIFT_UI_ACTOR void (^)(BOOL result))completionHandler
 {
     UIAlertController* alert = [UIAlertController alertControllerWithTitle:self.title
                                                                    message:message
@@ -80,14 +87,10 @@ - (void)     webView:(WKWebView*)webView runJavaScriptConfirmPanelWithMessage:(N
         }];
     [alert addAction:cancel];
 
-    UIViewController* rootController = [UIApplication sharedApplication].delegate.window.rootViewController;
-
-    [rootController presentViewController:alert animated:YES completion:nil];
+    [[self topViewController] presentViewController:alert animated:YES completion:nil];
 }
 
-- (void)      webView:(WKWebView*)webView runJavaScriptTextInputPanelWithPrompt:(NSString*)prompt
-          defaultText:(NSString*)defaultText initiatedByFrame:(WKFrameInfo*)frame
-    completionHandler:(void (^)(NSString* result))completionHandler
+- (void)webView:(WKWebView*)webView runJavaScriptTextInputPanelWithPrompt:(NSString*)prompt defaultText:(NSString*)defaultText initiatedByFrame:(WKFrameInfo*)frame completionHandler:(CDV_SWIFT_UI_ACTOR void (^)(NSString* result))completionHandler
 {
     UIAlertController* alert = [UIAlertController alertControllerWithTitle:self.title
                                                                    message:prompt
@@ -116,12 +119,10 @@ - (void)      webView:(WKWebView*)webView runJavaScriptTextInputPanelWithPrompt:
         textField.text = defaultText;
     }];
 
-    UIViewController* rootController = [UIApplication sharedApplication].delegate.window.rootViewController;
-
-    [rootController presentViewController:alert animated:YES completion:nil];
+    [[self topViewController] presentViewController:alert animated:YES completion:nil];
 }
 
-- (WKWebView*) webView:(WKWebView*)webView createWebViewWithConfiguration:(WKWebViewConfiguration*)configuration forNavigationAction:(WKNavigationAction*)navigationAction windowFeatures:(WKWindowFeatures*)windowFeatures
+- (nullable WKWebView*)webView:(WKWebView*)webView createWebViewWithConfiguration:(WKWebViewConfiguration*)configuration forNavigationAction:(WKNavigationAction*)navigationAction windowFeatures:(WKWindowFeatures*)windowFeatures
 {
     if (!navigationAction.targetFrame.isMainFrame) {
         if (self.allowNewWindows) {
@@ -135,8 +136,7 @@ - (WKWebView*) webView:(WKWebView*)webView createWebViewWithConfiguration:(WKWeb
 
             [windows addObject:vc];
 
-            UIViewController* rootController = [UIApplication sharedApplication].delegate.window.rootViewController;
-            [rootController presentViewController:vc animated:YES completion:nil];
+            [[self topViewController] presentViewController:vc animated:YES completion:nil];
             return v;
         } else {
             [webView loadRequest:navigationAction.request];
@@ -159,5 +159,17 @@ - (void)webViewDidClose:(WKWebView*)webView
     // We do not allow closing the primary WebView
 }
 
+#pragma mark - Utility Methods
+
+- (nullable UIViewController *)topViewController
+{
+    UIViewController *vc = self.viewController;
+
+    while (vc.presentedViewController != nil && ![vc.presentedViewController isBeingDismissed]) {
+        vc = vc.presentedViewController;
+    }
+
+    return vc;
+}
 
 @end