Reload the web view every 10 renderings to clean it up. Issue #1487

iOS/Article/WebViewController.swift

@@ -28,6 +28,7 @@ class WebViewController: UIViewController {
 	private var topShowBarsViewConstraint: NSLayoutConstraint!
 	private var bottomShowBarsViewConstraint: NSLayoutConstraint!
 	
+	private var renderingTracker = 0
 	private var webView: WKWebView!
 	private lazy var contextMenuInteraction = UIContextMenuInteraction(delegate: self)
 	private var isFullScreenAvailable: Bool {
@@ -41,7 +42,7 @@ class WebViewController: UIViewController {
 	private var isShowingExtractedArticle = false {
 		didSet {
 			if isShowingExtractedArticle != oldValue {
-				reloadHTML()
+				renderPage()
 			}
 		}
 	}
@@ -62,7 +63,7 @@ class WebViewController: UIViewController {
 				startArticleExtractor()
 			}
 			if article != oldValue {
-				reloadHTML()
+				renderPage()
 			}
 		}
 	}
@@ -101,6 +102,7 @@ class WebViewController: UIViewController {
 				self.view.bottomAnchor.constraint(equalTo: webView.bottomAnchor)
 			])
 
+			// Configure the tap zones
 			self.configureTopShowBarsView()
 			self.configureBottomShowBarsView()
 			
@@ -114,53 +116,13 @@ class WebViewController: UIViewController {
 
 			// Even though page.html should be loaded into this webview, we have to do it again
 			// to work around this bug: http://www.openradar.me/22855188
-			let url = Bundle.main.url(forResource: "page", withExtension: "html")!
+			self.reloadHTML()
-			webView.loadFileURL(url, allowingReadAccessTo: url.deletingLastPathComponent())
+			
-
 			self.view.setNeedsLayout()
 			self.view.layoutIfNeeded()
 		}
 		
 	}
-
-	func reloadHTML() {
-		guard let webView = webView else { return }
-		
-		let style = ArticleStylesManager.shared.currentStyle
-		let rendering: ArticleRenderer.Rendering
-
-		if let articleExtractor = articleExtractor, articleExtractor.state == .processing {
-			rendering = ArticleRenderer.loadingHTML(style: style)
-		} else if let articleExtractor = articleExtractor, articleExtractor.state == .failedToParse, let article = article {
-			rendering = ArticleRenderer.articleHTML(article: article, style: style, useImageIcon: true)
-		} else if let article = article, let extractedArticle = extractedArticle {
-			if isShowingExtractedArticle {
-				rendering = ArticleRenderer.articleHTML(article: article, extractedArticle: extractedArticle, style: style, useImageIcon: true)
-			} else {
-				rendering = ArticleRenderer.articleHTML(article: article, style: style, useImageIcon: true)
-			}
-		} else if let article = article {
-			rendering = ArticleRenderer.articleHTML(article: article, style: style, useImageIcon: true)
-		} else {
-			rendering = ArticleRenderer.noSelectionHTML(style: style)
-		}
-		
-		let templateData = TemplateData(style: rendering.style, body: rendering.html)
-		
-		let encoder = JSONEncoder()
-		var render = "error();"
-		if let data = try? encoder.encode(templateData) {
-			let json = String(data: data, encoding: .utf8)!
-			render = "render(\(json), \(restoreOffset));"
-		}
-
-		restoreOffset = 0
-		
-		WebViewProvider.shared.articleIconSchemeHandler.currentArticle = article
-		webView.scrollView.setZoomScale(1.0, animated: false)
-		webView.evaluateJavaScript(render)
-		
-	}
 	
 	// MARK: Notifications
 	
@@ -293,7 +255,7 @@ extension WebViewController: ArticleExtractorDelegate {
 	func articleExtractionDidFail(with: Error) {
 		stopArticleExtractor()
 		articleExtractorButtonState = .error
-		reloadHTML()
+		renderPage()
 	}
 
 	func articleExtractionDidComplete(extractedArticle: ExtractedArticle) {
@@ -377,7 +339,7 @@ extension WebViewController: WKNavigationDelegate {
 	}
 
 	func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
-		self.reloadHTML()
+		self.renderPage()
 	}
 	
 }
@@ -460,6 +422,59 @@ private struct ImageClickMessage: Codable {
 
 private extension WebViewController {
 
+	func reloadHTML() {
+		let url = Bundle.main.url(forResource: "page", withExtension: "html")!
+		webView.loadFileURL(url, allowingReadAccessTo: url.deletingLastPathComponent())
+		renderingTracker = 0
+	}
+
+	func renderPage() {
+		guard let webView = webView else { return }
+		 
+		// It looks like we need to clean up the webview every once in a while by reloading it from scratch
+		// Otherwise it will stop responding or cause rendering artifacts.  This typically only comes into
+		// play on the iPad where we aren't constantly pushing and popping this controller.
+		if (renderingTracker > 10) {
+			reloadHTML()
+		}
+		renderingTracker += 1
+		
+		let style = ArticleStylesManager.shared.currentStyle
+		let rendering: ArticleRenderer.Rendering
+
+		if let articleExtractor = articleExtractor, articleExtractor.state == .processing {
+			rendering = ArticleRenderer.loadingHTML(style: style)
+		} else if let articleExtractor = articleExtractor, articleExtractor.state == .failedToParse, let article = article {
+			rendering = ArticleRenderer.articleHTML(article: article, style: style, useImageIcon: true)
+		} else if let article = article, let extractedArticle = extractedArticle {
+			if isShowingExtractedArticle {
+				rendering = ArticleRenderer.articleHTML(article: article, extractedArticle: extractedArticle, style: style, useImageIcon: true)
+			} else {
+				rendering = ArticleRenderer.articleHTML(article: article, style: style, useImageIcon: true)
+			}
+		} else if let article = article {
+			rendering = ArticleRenderer.articleHTML(article: article, style: style, useImageIcon: true)
+		} else {
+			rendering = ArticleRenderer.noSelectionHTML(style: style)
+		}
+		
+		let templateData = TemplateData(style: rendering.style, body: rendering.html)
+		
+		let encoder = JSONEncoder()
+		var render = "error();"
+		if let data = try? encoder.encode(templateData) {
+			let json = String(data: data, encoding: .utf8)!
+			render = "render(\(json), \(restoreOffset));"
+		}
+
+		restoreOffset = 0
+		
+		WebViewProvider.shared.articleIconSchemeHandler.currentArticle = article
+		webView.scrollView.setZoomScale(1.0, animated: false)
+		webView.evaluateJavaScript(render)
+		
+	}
+	
 	func finalScrollPosition() -> CGFloat {
 		return webView.scrollView.contentSize.height - webView.scrollView.bounds.height + webView.scrollView.safeAreaInsets.bottom
 	}