Revert webview changes that might be the cause of the no-scroll-on-coming-back-from-sleep bug.

iOS/Article/PreloadedWebView.swift

@@ -0,0 +1,75 @@
+//
+//  PreloadedWebView.swift
+//  NetNewsWire-iOS
+//
+//  Created by Maurice Parker on 2/25/20.
+//  Copyright © 2020 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import WebKit
+
+class PreloadedWebView: WKWebView {
+	
+	private var isReady: Bool = false
+	private var readyCompletion: (() -> Void)?
+
+	init(articleIconSchemeHandler: ArticleIconSchemeHandler) {
+		let preferences = WKPreferences()
+		preferences.javaScriptCanOpenWindowsAutomatically = false
+
+		let configuration = WKWebViewConfiguration()
+		configuration.preferences = preferences
+		configuration.defaultWebpagePreferences.allowsContentJavaScript = true
+		configuration.setValue(true, forKey: "allowUniversalAccessFromFileURLs")
+		configuration.allowsInlineMediaPlayback = true
+		configuration.mediaTypesRequiringUserActionForPlayback = .audio
+		configuration.setURLSchemeHandler(articleIconSchemeHandler, forURLScheme: ArticleRenderer.imageIconScheme)
+		
+		super.init(frame: .zero, configuration: configuration)
+	}
+	
+	required init?(coder: NSCoder) {
+		super.init(coder: coder)
+	}
+	
+	func preload() {
+		navigationDelegate = self
+		loadFileURL(ArticleRenderer.blank.url, allowingReadAccessTo: ArticleRenderer.blank.baseURL)
+	}
+	
+	func ready(completion: @escaping () -> Void) {
+		if isReady {
+			completeRequest(completion: completion)
+		} else {
+			readyCompletion = completion
+		}
+	}
+	
+}
+
+// MARK: WKScriptMessageHandler
+
+extension PreloadedWebView: WKNavigationDelegate {
+
+	func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
+		isReady = true
+		if let completion = readyCompletion {
+			completeRequest(completion: completion)
+			readyCompletion = nil
+		}
+	}
+		
+}
+
+// MARK: Private
+
+private extension PreloadedWebView {
+	
+	func completeRequest(completion: @escaping () -> Void) {
+		isReady = false
+		navigationDelegate = nil
+		completion()
+	}
+	
+}

iOS/Article/WebViewController.swift

@@ -31,8 +31,8 @@ class WebViewController: UIViewController {
 	private var topShowBarsViewConstraint: NSLayoutConstraint!
 	private var bottomShowBarsViewConstraint: NSLayoutConstraint!
 	
-	var webView: WKWebView? {
-		return view.subviews[0] as? WKWebView
+	private var webView: PreloadedWebView? {
+		return view.subviews[0] as? PreloadedWebView
 	}
 
 	private lazy var contextMenuInteraction = UIContextMenuInteraction(delegate: self)
@@ -352,14 +352,22 @@ extension WebViewController: UIContextMenuInteractionDelegate {
 
 extension WebViewController: WKNavigationDelegate {
 	
+	func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
+		for (index, view) in view.subviews.enumerated() {
+			if index != 0, let oldWebView = view as? PreloadedWebView {
+				oldWebView.removeFromSuperview()
+			}
+		}
+	}
+
 	func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
-		
+
 		if navigationAction.navigationType == .linkActivated {
 			guard let url = navigationAction.request.url else {
 				decisionHandler(.allow)
 				return
 			}
-			
+
 			let components = URLComponents(url: url, resolvingAgainstBaseURL: false)
 			if components?.scheme == "http" || components?.scheme == "https" {
 				decisionHandler(.cancel)
@@ -373,14 +381,14 @@ extension WebViewController: WKNavigationDelegate {
 						self.openURLInSafariViewController(url)
 					}
 				}
-				
+
 			} else if components?.scheme == "mailto" {
 				decisionHandler(.cancel)
-				
+
 				guard let emailAddress = url.percentEncodedEmailAddress else {
 					return
 				}
-				
+
 				if UIApplication.shared.canOpenURL(emailAddress) {
 					UIApplication.shared.open(emailAddress, options: [.universalLinksOnly : false], completionHandler: nil)
 				} else {
@@ -390,11 +398,11 @@ extension WebViewController: WKNavigationDelegate {
 				}
 			} else if components?.scheme == "tel" {
 				decisionHandler(.cancel)
-				
+
 				if UIApplication.shared.canOpenURL(url) {
 					UIApplication.shared.open(url, options: [.universalLinksOnly : false], completionHandler: nil)
 				}
-				
+
 			} else {
 				decisionHandler(.allow)
 			}
@@ -406,7 +414,7 @@ extension WebViewController: WKNavigationDelegate {
 	func webViewWebContentProcessDidTerminate(_ webView: WKWebView) {
 		fullReload()
 	}
-	
+
 }
 
 // MARK: WKUIDelegate
@@ -506,63 +514,55 @@ private extension WebViewController {
 
 	func loadWebView(replaceExistingWebView: Bool = false) {
 		guard isViewLoaded else { return }
-		
+
 		if !replaceExistingWebView, let webView = webView {
 			self.renderPage(webView)
 			return
 		}
-		
-		let preferences = WKPreferences()
-		preferences.javaScriptCanOpenWindowsAutomatically = false
 
-		/// The defaults for `preferredContentMode` and `allowsContentJavaScript` are suitable
-		/// and don't need to be explicitly set.
-		/// `allowsContentJavaScript` replaces `WKPreferences.javascriptEnabled`.
-		let webpagePreferences = WKWebpagePreferences()
+		coordinator.webViewProvider.dequeueWebView() { webView in
+
+			webView.ready {
+
+				// Add the webview
+				webView.translatesAutoresizingMaskIntoConstraints = false
+				self.view.insertSubview(webView, at: 0)
+				NSLayoutConstraint.activate([
+					self.view.leadingAnchor.constraint(equalTo: webView.leadingAnchor),
+					self.view.trailingAnchor.constraint(equalTo: webView.trailingAnchor),
+					self.view.topAnchor.constraint(equalTo: webView.topAnchor),
+					self.view.bottomAnchor.constraint(equalTo: webView.bottomAnchor)
+				])
+
+				// UISplitViewController reports the wrong size to WKWebView which can cause horizontal
+				// rubberbanding on the iPad.  This interferes with our UIPageViewController preventing
+				// us from easily swiping between WKWebViews.  This hack fixes that.
+				webView.scrollView.contentInset = UIEdgeInsets(top: 0, left: -1, bottom: 0, right: 0)
+
+				webView.scrollView.setZoomScale(1.0, animated: false)
+
+				self.view.setNeedsLayout()
+				self.view.layoutIfNeeded()
+
+				// Configure the webview
+				webView.navigationDelegate = self
+				webView.uiDelegate = self
+				webView.scrollView.delegate = self
+				self.configureContextMenuInteraction()
+
+				webView.configuration.userContentController.add(WrapperScriptMessageHandler(self), name: MessageName.imageWasClicked)
+				webView.configuration.userContentController.add(WrapperScriptMessageHandler(self), name: MessageName.imageWasShown)
+				webView.configuration.userContentController.add(WrapperScriptMessageHandler(self), name: MessageName.showFeedInspector)
+
+				self.renderPage(webView)
+
+			}
 
-		let configuration = WKWebViewConfiguration()
-		configuration.defaultWebpagePreferences = webpagePreferences
-		configuration.preferences = preferences
-		configuration.setValue(true, forKey: "allowUniversalAccessFromFileURLs")
-		configuration.allowsInlineMediaPlayback = true
-		configuration.mediaTypesRequiringUserActionForPlayback = .audio
-		if #available(iOS 15.4, *) {
-			configuration.preferences.isElementFullscreenEnabled = true
 		}
-		configuration.setURLSchemeHandler(articleIconSchemeHandler, forURLScheme: ArticleRenderer.imageIconScheme)
 
-		let webView = WKWebView(frame: self.view.bounds, configuration: configuration)
-		webView.isOpaque = false;
-		webView.backgroundColor = .clear;
-
-		// Add the webview - using autolayout will cause fullscreen video to fail and lose the web view
-		webView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
-		self.view.insertSubview(webView, at: 0)
-
-		// UISplitViewController reports the wrong size to WKWebView which can cause horizontal
-		// rubberbanding on the iPad.  This interferes with our UIPageViewController preventing
-		// us from easily swiping between WKWebViews.  This hack fixes that.
-		webView.scrollView.contentInset = UIEdgeInsets(top: 0, left: -1, bottom: 0, right: 0)
-
-		webView.scrollView.setZoomScale(1.0, animated: false)
-
-		self.view.setNeedsLayout()
-		self.view.layoutIfNeeded()
-
-		// Configure the webview
-		webView.navigationDelegate = self
-		webView.uiDelegate = self
-		webView.scrollView.delegate = self
-		self.configureContextMenuInteraction()
-
-		webView.configuration.userContentController.add(WrapperScriptMessageHandler(self), name: MessageName.imageWasClicked)
-		webView.configuration.userContentController.add(WrapperScriptMessageHandler(self), name: MessageName.imageWasShown)
-		webView.configuration.userContentController.add(WrapperScriptMessageHandler(self), name: MessageName.showFeedInspector)
-
-		self.renderPage(webView)
 	}
 
-	func renderPage(_ webView: WKWebView?) {
+	func renderPage(_ webView: PreloadedWebView?) {
 		guard let webView = webView else { return }
 		 
 		let theme = ArticleThemesManager.shared.currentTheme

iOS/Article/WebViewProvider.swift

@@ -0,0 +1,103 @@
+//
+//  WebViewProvider.swift
+//  NetNewsWire-iOS
+//
+//  Created by Maurice Parker on 9/21/19.
+//  Copyright © 2019 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import RSCore
+import WebKit
+
+/// WKWebView has an awful behavior of a flash to white on first load when in dark mode.
+/// Keep a queue of WebViews where we've already done a trivial load so that by the time we need them in the UI, they're past the flash-to-shite part of their lifecycle.
+class WebViewProvider: NSObject {
+	
+	private let articleIconSchemeHandler: ArticleIconSchemeHandler
+	private let operationQueue = MainThreadOperationQueue()
+	private var queue = NSMutableArray()
+	
+	init(coordinator: SceneCoordinator) {
+		articleIconSchemeHandler = ArticleIconSchemeHandler(coordinator: coordinator)
+		super.init()
+		replenishQueueIfNeeded()
+	}
+
+	func replenishQueueIfNeeded() {
+		operationQueue.add(WebViewProviderReplenishQueueOperation(queue: queue, articleIconSchemeHandler: articleIconSchemeHandler))
+	}
+	
+	func dequeueWebView(completion: @escaping (PreloadedWebView) -> ()) {
+		operationQueue.add(WebViewProviderDequeueOperation(queue: queue, articleIconSchemeHandler: articleIconSchemeHandler, completion: completion))
+		operationQueue.add(WebViewProviderReplenishQueueOperation(queue: queue, articleIconSchemeHandler: articleIconSchemeHandler))
+	}
+	
+}
+
+class WebViewProviderReplenishQueueOperation: MainThreadOperation {
+	
+	// MainThreadOperation
+	public var isCanceled = false
+	public var id: Int?
+	public weak var operationDelegate: MainThreadOperationDelegate?
+	public var name: String? = "WebViewProviderReplenishQueueOperation"
+	public var completionBlock: MainThreadOperation.MainThreadOperationCompletionBlock?
+
+	private let minimumQueueDepth = 3
+
+	private var queue: NSMutableArray
+	private var articleIconSchemeHandler: ArticleIconSchemeHandler
+	
+	init(queue: NSMutableArray, articleIconSchemeHandler: ArticleIconSchemeHandler) {
+		self.queue = queue
+		self.articleIconSchemeHandler = articleIconSchemeHandler
+	}
+	
+	func run() {
+		while queue.count < minimumQueueDepth {
+			let webView = PreloadedWebView(articleIconSchemeHandler: articleIconSchemeHandler)
+			webView.preload()
+			queue.insert(webView, at: 0)
+		}
+		self.operationDelegate?.operationDidComplete(self)
+	}
+	
+}
+
+class WebViewProviderDequeueOperation: MainThreadOperation {
+	
+	// MainThreadOperation
+	public var isCanceled = false
+	public var id: Int?
+	public weak var operationDelegate: MainThreadOperationDelegate?
+	public var name: String? = "WebViewProviderFlushQueueOperation"
+	public var completionBlock: MainThreadOperation.MainThreadOperationCompletionBlock?
+
+	private var queue: NSMutableArray
+	private var articleIconSchemeHandler: ArticleIconSchemeHandler
+	private var completion: (PreloadedWebView) -> ()
+	
+	init(queue: NSMutableArray, articleIconSchemeHandler: ArticleIconSchemeHandler, completion: @escaping (PreloadedWebView) -> ()) {
+		self.queue = queue
+		self.articleIconSchemeHandler = articleIconSchemeHandler
+		self.completion = completion
+	}
+	
+	func run() {
+		if let webView = queue.lastObject as? PreloadedWebView {
+			self.completion(webView)
+			self.queue.remove(webView)
+			self.operationDelegate?.operationDidComplete(self)
+			return
+		}
+
+		assertionFailure("Creating PreloadedWebView in \(#function); queue has run dry.")
+		
+		let webView = PreloadedWebView(articleIconSchemeHandler: articleIconSchemeHandler)
+		webView.preload()
+		self.completion(webView)
+		self.operationDelegate?.operationDidComplete(self)
+	}
+	
+}

iOS/MainFeed/MainFeedViewController.swift

@@ -35,10 +35,10 @@ class MainFeedViewController: UITableViewController, UndoableCommandRunner {
 	private let keyboardManager = KeyboardManager(type: .sidebar)
 	override var keyCommands: [UIKeyCommand]? {
 		
-		// If the first responder is the WKWebView we don't want to supply any keyboard
+		// If the first responder is the WKWebView (PreloadedWebView) we don't want to supply any keyboard
 		// commands that the system is looking for by going up the responder chain. They will interfere with
 		// the WKWebViews built in hardware keyboard shortcuts, specifically the up and down arrow keys.
-		guard let current = UIResponder.currentFirstResponder, !(current is WKWebView) else { return nil }
+		guard let current = UIResponder.currentFirstResponder, !(current is PreloadedWebView) else { return nil }
 		
 		return keyboardManager.keyCommands
 	}

iOS/MainTimeline/MainTimelineViewController.swift

@@ -98,11 +98,11 @@ class MainTimelineViewController: UITableViewController, UndoableCommandRunner {
 	private let keyboardManager = KeyboardManager(type: .timeline)
 	override var keyCommands: [UIKeyCommand]? {
 		
-		// If the first responder is the WKWebView we don't want to supply any keyboard
+		// If the first responder is the WKWebView (PreloadedWebView) we don't want to supply any keyboard
 		// commands that the system is looking for by going up the responder chain. They will interfere with
 		// the WKWebViews built in hardware keyboard shortcuts, specifically the up and down arrow keys.
-		guard let current = UIResponder.currentFirstResponder, !(current is WKWebView) else { return nil }
-		
+		guard let current = UIResponder.currentFirstResponder, !(current is PreloadedWebView) else { return nil }
+
 		return keyboardManager.keyCommands
 	}
 	

iOS/SceneCoordinator.swift

@@ -40,20 +40,22 @@ struct FeedNode: Hashable {
 }
 
 class SceneCoordinator: NSObject, UndoableCommandRunner {
-	
+
 	var undoableCommands = [UndoableCommand]()
 	var undoManager: UndoManager? {
 		return rootSplitViewController.undoManager
 	}
-	
+
+	lazy var webViewProvider = WebViewProvider(coordinator: self)
+
 	private var activityManager = ActivityManager()
-	
+
 	private var rootSplitViewController: RootSplitViewController!
 
 	private var mainFeedViewController: MainFeedViewController!
 	private var mainTimelineViewController: MainTimelineViewController?
 	private var articleViewController: ArticleViewController?
-	
+
 	private let fetchAndMergeArticlesQueue = CoalescingQueue(name: "Fetch and Merge Articles", interval: 0.5)
 	private let rebuildBackingStoresQueue = CoalescingQueue(name: "Rebuild The Backing Stores", interval: 0.5)
 	private var fetchSerialNumber = 0