Selective removal of content scripts to preserve web extension scripts

Sources/BrowserServicesKit/ContentScopeScript/UserContentController.swift

@@ -42,6 +42,7 @@ public protocol UserContentControllerNewContent {
 
 @objc(UserContentController)
 final public class UserContentController: WKUserContentController {
+
     public let privacyConfigurationManager: PrivacyConfigurationManaging
     @MainActor
     public weak var delegate: UserContentControllerDelegate?
@@ -78,7 +79,7 @@ final public class UserContentController: WKUserContentController {
     @Published @MainActor public private(set) var contentBlockingAssets: ContentBlockingAssets? {
         willSet {
             self.removeAllContentRuleLists()
-            self.removeAllUserScripts()
+            self.removeInstalledUserScripts()
 
             if let contentBlockingAssets = newValue {
                 Logger.contentBlocking.debug("📚 installing \(contentBlockingAssets.debugDescription)")
@@ -216,10 +217,39 @@ final public class UserContentController: WKUserContentController {
         super.removeAllContentRuleLists()
     }
 
+#if os(macOS)
+    static let removeUserScriptSelector = "removeUserScript:"
+    private var removeUserScriptSupported: Bool {
+        responds(to: NSSelectorFromString("_" + Self.removeUserScriptSelector))
+    }
+    private var installedUserScripts = [WKUserScript]()
+#endif
+
     @MainActor
     private func installUserScripts(_ wkUserScripts: [WKUserScript], handlers: [UserScript]) {
         handlers.forEach { self.addHandler($0) }
         wkUserScripts.forEach(self.addUserScript)
+
+#if os(macOS)
+        installedUserScripts.append(contentsOf: wkUserScripts)
+#endif
+    }
+
+    private func removeInstalledUserScripts() {
+#if os(macOS)
+        // Avoid removal of web extension scripts
+        if removeUserScriptSupported {
+            for installedUserScript in installedUserScripts {
+                self.perform(NSSelectorFromString("_" + Self.removeUserScriptSelector), with: installedUserScript)
+            }
+            installedUserScripts.removeAll()
+        } else {
+            self.removeAllUserScripts()
+        }
+#else
+        self.removeAllUserScripts()
+#endif
+
     }
 
     @MainActor

Sources/Common/Extensions/URLExtension.swift

@@ -93,6 +93,7 @@ extension URL {
         public static let about = NavigationalScheme(rawValue: "about")
         public static let duck = NavigationalScheme(rawValue: "duck")
         public static let mailto = NavigationalScheme(rawValue: "mailto")
+        public static let webkitExtension = NavigationalScheme(rawValue: "webkit-extension")
 
         public init(rawValue: String) {
             self.rawValue = rawValue