Dactyloidae iOS initial commit

mobile/ios/Client/Frontend/Browser/ContextMenuHelper.swift

@@ -0,0 +1,108 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import WebKit
+
+protocol ContextMenuHelperDelegate: class {
+    func contextMenuHelper(_ contextMenuHelper: ContextMenuHelper, didLongPressElements elements: ContextMenuHelper.Elements, gestureRecognizer: UIGestureRecognizer)
+    func contextMenuHelper(_ contextMenuHelper: ContextMenuHelper, didCancelGestureRecognizer: UIGestureRecognizer)
+}
+
+class ContextMenuHelper: NSObject {
+    struct Elements {
+        let link: URL?
+        let image: URL?
+    }
+
+    fileprivate weak var tab: Tab?
+
+    weak var delegate: ContextMenuHelperDelegate?
+
+    fileprivate var nativeHighlightLongPressRecognizer: UILongPressGestureRecognizer?
+    fileprivate var elements: Elements?
+
+    required init(tab: Tab) {
+        super.init()
+
+        self.tab = tab
+
+        guard let path = Bundle.main.path(forResource: "ContextMenu", ofType: "js"),
+                let source = try? NSString(contentsOfFile: path, encoding: String.Encoding.utf8.rawValue) as String,
+                let webView = tab.webView else {
+            return
+        }
+
+        let userScript = WKUserScript(source: source, injectionTime: WKUserScriptInjectionTime.atDocumentEnd, forMainFrameOnly: false)
+        webView.configuration.userContentController.addUserScript(userScript)
+
+        nativeHighlightLongPressRecognizer = gestureRecognizerWithDescriptionFragment("action=_highlightLongPressRecognized:") as? UILongPressGestureRecognizer
+
+        if let nativeLongPressRecognizer = gestureRecognizerWithDescriptionFragment("action=_longPressRecognized:") as? UILongPressGestureRecognizer {
+            nativeLongPressRecognizer.removeTarget(nil, action: nil)
+            nativeLongPressRecognizer.addTarget(self, action: #selector(longPressGestureDetected(_:)))
+        }
+    }
+
+    func gestureRecognizerWithDescriptionFragment(_ descriptionFragment: String) -> UIGestureRecognizer? {
+        return tab?.webView?.scrollView.subviews.flatMap({ $0.gestureRecognizers }).joined().first(where: { $0.description.contains(descriptionFragment) })
+    }
+
+    func longPressGestureDetected(_ sender: UIGestureRecognizer) {
+        if sender.state == .cancelled {
+            delegate?.contextMenuHelper(self, didCancelGestureRecognizer: sender)
+            return
+        }
+
+        guard sender.state == .began, let elements = self.elements else {
+            return
+        }
+
+        delegate?.contextMenuHelper(self, didLongPressElements: elements, gestureRecognizer: sender)
+
+        // To prevent the tapped link from proceeding with navigation, "cancel" the native WKWebView
+        // `_highlightLongPressRecognizer`. This preserves the original behavior as seen here:
+        // https://github.com/WebKit/webkit/blob/d591647baf54b4b300ca5501c21a68455429e182/Source/WebKit/UIProcess/ios/WKContentViewInteraction.mm#L1600-L1614
+        if let nativeHighlightLongPressRecognizer = self.nativeHighlightLongPressRecognizer,
+            nativeHighlightLongPressRecognizer.isEnabled {
+            nativeHighlightLongPressRecognizer.isEnabled = false
+            nativeHighlightLongPressRecognizer.isEnabled = true
+        }
+
+        self.elements = nil
+    }
+}
+
+extension ContextMenuHelper: TabContentScript {
+    class func name() -> String {
+        return "ContextMenuHelper"
+    }
+
+    func scriptMessageHandlerName() -> String? {
+        return "contextMenuMessageHandler"
+    }
+
+    func userContentController(_ userContentController: WKUserContentController, didReceiveScriptMessage message: WKScriptMessage) {
+        guard let data = message.body as? [String: AnyObject] else {
+            return
+        }
+
+        var linkURL: URL?
+        if let urlString = data["link"] as? String,
+                let escapedURLString = urlString.addingPercentEncoding(withAllowedCharacters: CharacterSet.URLAllowedCharacterSet()) {
+            linkURL = URL(string: escapedURLString)
+        }
+
+        var imageURL: URL?
+        if let urlString = data["image"] as? String,
+                let escapedURLString = urlString.addingPercentEncoding(withAllowedCharacters: CharacterSet.URLAllowedCharacterSet()) {
+            imageURL = URL(string: escapedURLString)
+        }
+
+        if linkURL != nil || imageURL != nil {
+            elements = Elements(link: linkURL, image: imageURL)
+        } else {
+            elements = nil
+        }
+    }
+}