SEBWIN-926: Implemented custom drag handler to suppress drag&drop beh…

…avior.

SafeExamBrowser.Browser/BrowserControl.cs

@@ -26,6 +26,7 @@ internal class BrowserControl : IBrowserControl
 		private readonly IDialogHandler dialogHandler;
 		private readonly IDisplayHandler displayHandler;
 		private readonly IDownloadHandler downloadHandler;
+		private readonly IDragHandler dragHandler;
 		private readonly IFocusHandler focusHandler;
 		private readonly IJsDialogHandler javaScriptDialogHandler;
 		private readonly IKeyboardHandler keyboardHandler;
@@ -49,6 +50,7 @@ public BrowserControl(
 			IDialogHandler dialogHandler,
 			IDisplayHandler displayHandler,
 			IDownloadHandler downloadHandler,
+			IDragHandler dragHandler,
 			IFocusHandler focusHandler,
 			IJsDialogHandler javaScriptDialogHandler,
 			IKeyboardHandler keyboardHandler,
@@ -61,6 +63,7 @@ public BrowserControl(
 			this.dialogHandler = dialogHandler;
 			this.displayHandler = displayHandler;
 			this.downloadHandler = downloadHandler;
+			this.dragHandler = dragHandler;
 			this.focusHandler = focusHandler;
 			this.javaScriptDialogHandler = javaScriptDialogHandler;
 			this.keyboardHandler = keyboardHandler;
@@ -133,6 +136,8 @@ public void Initialize()
 			control.ContextReleased += (w, b, f) => renderProcessMessageHandler.OnContextReleased(w, b, f);
 			control.DialogClosed += (w, b) => javaScriptDialogHandler.OnDialogClosed(w, b);
 			control.DownloadUpdated += (w, b, d, c) => downloadHandler.OnDownloadUpdated(w, b, d, c);
+			control.DragEnterCefSharp += (w, b, d, m, a) => a.Value = dragHandler.OnDragEnter(w, b, d, m);
+			control.DraggableRegionsChanged += (w, b, f, r) => dragHandler.OnDraggableRegionsChanged(w, b, f, r);
 			control.FaviconUrlChanged += (w, b, u) => displayHandler.OnFaviconUrlChange(w, b, u);
 			control.FileDialogRequested += (w, b, m, t, p, f, e, d, c) => dialogHandler.OnFileDialog(w, b, m, t, p, f, e, d, c);
 			control.FocusedNodeChanged += (w, b, f, n) => renderProcessMessageHandler.OnFocusedNodeChanged(w, b, f, n);

SafeExamBrowser.Browser/BrowserWindow.cs

@@ -157,6 +157,7 @@ internal void InitializeControl()
 			var displayHandler = new DisplayHandler();
 			var downloadLogger = logger.CloneFor($"{nameof(DownloadHandler)} #{Id}");
 			var downloadHandler = new DownloadHandler(appConfig, downloadLogger, settings, WindowSettings);
+			var dragHandler = new DragHandler();
 			var focusHandler = new FocusHandler();
 			var javaScriptDialogHandler = new JavaScriptDialogHandler();
 			var keyboardHandler = new KeyboardHandler();
@@ -198,7 +199,19 @@ internal void InitializeControl()
 
 			InitializeRequestFilter(requestFilter);
 
-			Control = new BrowserControl(clipboard, cefSharpControl, dialogHandler, displayHandler, downloadHandler, focusHandler, javaScriptDialogHandler, keyboardHandler, controlLogger, renderHandler, requestHandler);
+			Control = new BrowserControl(
+				clipboard,
+				cefSharpControl,
+				dialogHandler,
+				displayHandler,
+				downloadHandler,
+				dragHandler,
+				focusHandler,
+				javaScriptDialogHandler,
+				keyboardHandler,
+				controlLogger,
+				renderHandler,
+				requestHandler);
 			Control.AddressChanged += Control_AddressChanged;
 			Control.LoadFailed += Control_LoadFailed;
 			Control.LoadingStateChanged += Control_LoadingStateChanged;

SafeExamBrowser.Browser/Handlers/DragHandler.cs

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * 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/.
+ */
+
+using System.Collections.Generic;
+using CefSharp;
+using CefSharp.Enums;
+
+namespace SafeExamBrowser.Browser.Handlers
+{
+	internal class DragHandler : IDragHandler
+	{
+		public bool OnDragEnter(IWebBrowser chromiumWebBrowser, IBrowser browser, IDragData dragData, DragOperationsMask mask)
+		{
+			return true;
+		}
+
+		public void OnDraggableRegionsChanged(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IList<DraggableRegion> regions)
+		{
+		}
+	}
+}

SafeExamBrowser.Browser/SafeExamBrowser.Browser.csproj

@@ -106,6 +106,7 @@
     <Compile Include="Handlers\DialogHandler.cs" />
     <Compile Include="Handlers\DisplayHandler.cs" />
     <Compile Include="Handlers\DownloadHandler.cs" />
+    <Compile Include="Handlers\DragHandler.cs" />
     <Compile Include="Handlers\FocusHandler.cs" />
     <Compile Include="Handlers\KeyboardHandler.cs" />
     <Compile Include="Handlers\RenderProcessMessageHandler.cs" />
@@ -128,6 +129,8 @@
     <Compile Include="Wrapper\Events\ContextReleasedEventHandler.cs" />
     <Compile Include="Wrapper\Events\DialogClosedEventHandler.cs" />
     <Compile Include="Wrapper\Events\DownloadUpdatedEventHandler.cs" />
+    <Compile Include="Wrapper\Events\DragEnterEventHandler.cs" />
+    <Compile Include="Wrapper\Events\DraggableRegionsChangedEventHandler.cs" />
     <Compile Include="Wrapper\Events\FaviconUrlChangedEventHandler.cs" />
     <Compile Include="Wrapper\Events\FileDialogRequestedEventHandler.cs" />
     <Compile Include="Wrapper\Events\FocusedNodeChangedEventHandler.cs" />
@@ -148,6 +151,7 @@
     <Compile Include="Wrapper\Handlers\DialogHandlerSwitch.cs" />
     <Compile Include="Wrapper\Handlers\DisplayHandlerSwitch.cs" />
     <Compile Include="Wrapper\Handlers\DownloadHandlerSwitch.cs" />
+    <Compile Include="Wrapper\Handlers\DragHandlerSwitch.cs" />
     <Compile Include="Wrapper\Handlers\FocusHandlerSwitch.cs" />
     <Compile Include="Handlers\JavaScriptDialogHandler.cs" />
     <Compile Include="Wrapper\Handlers\JavaScriptDialogHandlerSwitch.cs" />

SafeExamBrowser.Browser/Wrapper/CefSharpBrowserControl.cs

@@ -8,6 +8,7 @@
 
 using System.Collections.Generic;
 using CefSharp;
+using CefSharp.Enums;
 using CefSharp.WinForms;
 using SafeExamBrowser.Browser.Handlers;
 using SafeExamBrowser.Browser.Wrapper.Events;
@@ -26,6 +27,8 @@ internal class CefSharpBrowserControl : ChromiumWebBrowser, ICefSharpControl
 		public event ContextReleasedEventHandler ContextReleased;
 		public event DialogClosedEventHandler DialogClosed;
 		public event DownloadUpdatedEventHandler DownloadUpdated;
+		public event DragEnterEventHandler DragEnterCefSharp;
+		public event DraggableRegionsChangedEventHandler DraggableRegionsChanged;
 		public event FaviconUrlChangedEventHandler FaviconUrlChanged;
 		public event FileDialogRequestedEventHandler FileDialogRequested;
 		public event FocusedNodeChangedEventHandler FocusedNodeChanged;
@@ -46,6 +49,7 @@ public CefSharpBrowserControl(ILifeSpanHandler lifeSpanHandler, string url) : ba
 			DialogHandler = new DialogHandlerSwitch();
 			DisplayHandler = new DisplayHandlerSwitch();
 			DownloadHandler = new DownloadHandlerSwitch();
+			DragHandler = new DragHandlerSwitch();
 			FocusHandler = new FocusHandlerSwitch();
 			JsDialogHandler = new JavaScriptDialogHandlerSwitch();
 			KeyboardHandler = new KeyboardHandlerSwitch();
@@ -110,6 +114,16 @@ public void OnDownloadUpdated(IWebBrowser webBrowser, IBrowser browser, Download
 			DownloadUpdated?.Invoke(webBrowser, browser, downloadItem, callback);
 		}
 
+		public void OnDragEnter(IWebBrowser webBrowser, IBrowser browser, IDragData dragData, DragOperationsMask mask, GenericEventArgs args)
+		{
+			DragEnterCefSharp?.Invoke(webBrowser, browser, dragData, mask, args);
+		}
+
+		public void OnDraggableRegionsChanged(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IList<DraggableRegion> regions)
+		{
+			DraggableRegionsChanged?.Invoke(webBrowser, browser, frame, regions);
+		}
+
 		public void OnFaviconUrlChange(IWebBrowser webBrowser, IBrowser browser, IList<string> urls)
 		{
 			FaviconUrlChanged?.Invoke(webBrowser, browser, urls);

SafeExamBrowser.Browser/Wrapper/CefSharpPopupControl.cs

@@ -8,6 +8,7 @@
 
 using System.Collections.Generic;
 using CefSharp;
+using CefSharp.Enums;
 using CefSharp.WinForms.Host;
 using SafeExamBrowser.Browser.Wrapper.Events;
 
@@ -24,6 +25,8 @@ internal class CefSharpPopupControl : ChromiumHostControl, ICefSharpControl
 		public event ContextReleasedEventHandler ContextReleased;
 		public event DialogClosedEventHandler DialogClosed;
 		public event DownloadUpdatedEventHandler DownloadUpdated;
+		public event DragEnterEventHandler DragEnterCefSharp;
+		public event DraggableRegionsChangedEventHandler DraggableRegionsChanged;
 		public event FaviconUrlChangedEventHandler FaviconUrlChanged;
 		public event FileDialogRequestedEventHandler FileDialogRequested;
 		public event FocusedNodeChangedEventHandler FocusedNodeChanged;
@@ -102,6 +105,16 @@ public void OnDownloadUpdated(IWebBrowser webBrowser, IBrowser browser, Download
 			DownloadUpdated?.Invoke(webBrowser, browser, downloadItem, callback);
 		}
 
+		public void OnDragEnter(IWebBrowser webBrowser, IBrowser browser, IDragData dragData, DragOperationsMask mask, GenericEventArgs args)
+		{
+			DragEnterCefSharp?.Invoke(webBrowser, browser, dragData, mask, args);
+		}
+
+		public void OnDraggableRegionsChanged(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IList<DraggableRegion> regions)
+		{
+			DraggableRegionsChanged?.Invoke(webBrowser, browser, frame, regions);
+		}
+
 		public void OnFaviconUrlChange(IWebBrowser webBrowser, IBrowser browser, IList<string> urls)
 		{
 			FaviconUrlChanged?.Invoke(webBrowser, browser, urls);

SafeExamBrowser.Browser/Wrapper/Events/DragEnterEventHandler.cs

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * 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/.
+ */
+
+using CefSharp;
+using CefSharp.Enums;
+
+namespace SafeExamBrowser.Browser.Wrapper.Events
+{
+	internal delegate void DragEnterEventHandler(IWebBrowser webBrowser, IBrowser browser, IDragData dragData, DragOperationsMask mask, GenericEventArgs args);
+}

SafeExamBrowser.Browser/Wrapper/Events/DraggableRegionsChangedEventHandler.cs

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * 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/.
+ */
+
+using System.Collections.Generic;
+using CefSharp;
+
+namespace SafeExamBrowser.Browser.Wrapper.Events
+{
+	internal delegate void DraggableRegionsChangedEventHandler(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IList<DraggableRegion> regions);
+}

SafeExamBrowser.Browser/Wrapper/Handlers/DragHandlerSwitch.cs

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * 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/.
+ */
+
+using System.Collections.Generic;
+using CefSharp;
+using CefSharp.Enums;
+using CefSharp.WinForms;
+using CefSharp.WinForms.Host;
+using SafeExamBrowser.Browser.Wrapper.Events;
+
+namespace SafeExamBrowser.Browser.Wrapper.Handlers
+{
+	internal class DragHandlerSwitch : IDragHandler
+	{
+		public bool OnDragEnter(IWebBrowser webBrowser, IBrowser browser, IDragData dragData, DragOperationsMask mask)
+		{
+			var args = new GenericEventArgs();
+
+			if (browser.IsPopup)
+			{
+				var control = ChromiumHostControl.FromBrowser(browser) as CefSharpPopupControl;
+
+				control?.OnDragEnter(webBrowser, browser, dragData, mask, args);
+			}
+			else
+			{
+				var control = ChromiumWebBrowser.FromBrowser(browser) as CefSharpBrowserControl;
+
+				control?.OnDragEnter(webBrowser, browser, dragData, mask, args);
+			}
+
+			return args.Value;
+		}
+
+		public void OnDraggableRegionsChanged(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IList<DraggableRegion> regions)
+		{
+			if (browser.IsPopup)
+			{
+				var control = ChromiumHostControl.FromBrowser(browser) as CefSharpPopupControl;
+
+				control?.OnDraggableRegionsChanged(webBrowser, browser, frame, regions);
+			}
+			else
+			{
+				var control = ChromiumWebBrowser.FromBrowser(browser) as CefSharpBrowserControl;
+
+				control?.OnDraggableRegionsChanged(webBrowser, browser, frame, regions);
+			}
+		}
+	}
+}

SafeExamBrowser.Browser/Wrapper/ICefSharpControl.cs

@@ -10,6 +10,7 @@
 using System.ComponentModel;
 using System.Windows.Forms;
 using CefSharp;
+using CefSharp.Enums;
 using CefSharp.WinForms;
 using SafeExamBrowser.Browser.Wrapper.Events;
 using KeyEventHandler = SafeExamBrowser.Browser.Wrapper.Events.KeyEventHandler;
@@ -27,6 +28,8 @@ internal interface ICefSharpControl : IChromiumWebBrowserBase, IWinFormsChromium
 		event ContextReleasedEventHandler ContextReleased;
 		event DialogClosedEventHandler DialogClosed;
 		event DownloadUpdatedEventHandler DownloadUpdated;
+		event DragEnterEventHandler DragEnterCefSharp;
+		event DraggableRegionsChangedEventHandler DraggableRegionsChanged;
 		event FaviconUrlChangedEventHandler FaviconUrlChanged;
 		event FileDialogRequestedEventHandler FileDialogRequested;
 		event FocusedNodeChangedEventHandler FocusedNodeChanged;
@@ -54,6 +57,8 @@ internal interface ICefSharpControl : IChromiumWebBrowserBase, IWinFormsChromium
 		void OnContextReleased(IWebBrowser webBrowser, IBrowser browser, IFrame frame);
 		void OnDialogClosed(IWebBrowser webBrowser, IBrowser browser);
 		void OnDownloadUpdated(IWebBrowser webBrowser, IBrowser browser, DownloadItem downloadItem, IDownloadItemCallback callback);
+		void OnDragEnter(IWebBrowser webBrowser, IBrowser browser, IDragData dragData, DragOperationsMask mask, GenericEventArgs args);
+		void OnDraggableRegionsChanged(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IList<DraggableRegion> regions);
 		void OnFaviconUrlChange(IWebBrowser webBrowser, IBrowser browser, IList<string> urls);
 		void OnFileDialog(IWebBrowser webBrowser, IBrowser browser, CefFileDialogMode mode, string title, string defaultFilePath, IReadOnlyCollection<string> acceptFilters, IReadOnlyCollection<string> acceptExtensions, IReadOnlyCollection<string> acceptDescriptions, IFileDialogCallback callback);
 		void OnFocusedNodeChanged(IWebBrowser webBrowser, IBrowser browser, IFrame frame, IDomNode node);