[WIP] Add search capabilities to WebKit based Browser

This changes adds a search dialog to WebKit browsers. The search dialog
is opened with Ctrl+F and has next/previous word matching capabilities.

Fixes: #2222

Author: trancexpress

bundles/org.eclipse.swt/Eclipse SWT WebKit/gtk/org/eclipse/swt/browser/WebKit.java

@@ -25,6 +25,7 @@
 import java.util.function.*;
 
 import org.eclipse.swt.*;
+import org.eclipse.swt.events.*;
 import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.internal.*;
 import org.eclipse.swt.internal.gtk.*;
@@ -96,7 +97,11 @@ class WebKit extends WebBrowser {
 	URI tlsErrorUri;
 	String tlsErrorType;
 
+	private Shell searchShell;
+	private String searchText;
+
 	boolean firstLoad = true;
+
 	static boolean FirstCreate = true;
 
 	/**
@@ -784,13 +789,25 @@ public void create (Composite parent, int style) {
 				onResize (event);
 				break;
 			}
+			case SWT.KeyDown: {
+				if (event.keyCode == 'f' && (event.stateMask & SWT.CTRL) == SWT.CTRL) {
+					openSearchDialog();
+				}
+				break;
+			}
 		}
 	};
 	browser.addListener (SWT.Dispose, listener);
 	browser.addListener (SWT.FocusIn, listener);
 	browser.addListener (SWT.KeyDown, listener);
 	browser.addListener (SWT.Resize, listener);
 
+	browser.addDisposeListener(e -> {
+		if (searchShell != null && !searchShell.isDisposed()) {
+			searchShell.close();
+		}
+	});
+
 	/*
 	* Bug in WebKitGTK.  MouseOver/MouseLeave events are not consistently sent from
 	* the DOM when the mouse enters and exits the browser control, see
@@ -2665,6 +2682,61 @@ private void webkit_settings_set(byte [] property, int value) {
 	OS.g_object_set(settings, property, value, 0);
 }
 
+private void openSearchDialog() {
+	if (webView == 0 || (searchShell != null && !searchShell.isDisposed())) {
+		return;
+	}
+	Shell shell = new Shell(browser.getShell(), SWT.TOOL | SWT.ON_TOP | SWT.RESIZE);
+	shell.setLayout(new FillLayout());
+	Point browserLocation = browser.getLocation();
+	Rectangle browserArea = browser.getClientArea();
+	Point location = browser.getShell().getLocation();
+	location.x += browserLocation.x;
+	location.y += browserLocation.y + Math.max(0, browserArea.height - 20);
+	shell.setLocation(location);
+	Composite composite = new Composite(shell, SWT.NONE);
+	GridLayout l = new GridLayout();
+	l.numColumns = 3;
+	composite.setLayout(l);
+	Text text = new Text(composite, SWT.BORDER);
+	Button next = new Button(composite, SWT.FLAT | SWT.ARROW | SWT.DOWN);
+	Button previous = new Button(composite, SWT.FLAT | SWT.ARROW | SWT.UP);
+
+	long findController = WebKitGTK.webkit_web_view_get_find_controller(webView);
+	Runnable searchNext = () -> search(findController, text::getText, WebKitGTK::webkit_find_controller_search_next);
+	Runnable searchPrevious = () -> search(findController, text::getText, WebKitGTK::webkit_find_controller_search_previous);
+	next.addSelectionListener(SelectionListener.widgetSelectedAdapter(e -> searchNext.run()));
+	previous.addSelectionListener(SelectionListener.widgetSelectedAdapter(e -> searchPrevious.run()));
+	text.addKeyListener(KeyListener.keyPressedAdapter(e -> {
+		if (e.keyCode == SWT.CR || e.keyCode == SWT.KEYPAD_CR) {
+			searchNext.run();
+		}
+	}));
+	shell.addDisposeListener(e -> {
+		WebKitGTK.webkit_find_controller_search_finish(findController);
+		searchShell = null;
+	});
+	shell.pack();
+	shell.open();
+	searchShell = shell;
+}
+
+private void search(long findController, Supplier<String> currentText, Consumer<Long> incrementSearch) {
+	int maxMatchesCount = WebKitGTK.G_MAXUINT; // TODO: how to set no max count here?
+	int searchOptions = WebKitGTK.WEBKIT_FIND_OPTIONS_WRAP_AROUND;
+	String text = currentText.get();
+	if (!text.equals(searchText)) {
+		if (searchText != null) {
+			WebKitGTK.webkit_find_controller_search_finish(findController);
+		}
+		searchText = text;
+		byte[] textToSearch = Converter.wcsToMbcs(searchText, true);
+		WebKitGTK.webkit_find_controller_search(findController, textToSearch, searchOptions, maxMatchesCount);
+	} else {
+		incrementSearch.accept(Long.valueOf(findController));
+	}
+}
+
 static Object convertToJava (long ctx, long value) {
 	int type = WebKitGTK.JSValueGetType (ctx, value);
 	switch (type) {

bundles/org.eclipse.swt/Eclipse SWT WebKit/gtk/org/eclipse/swt/internal/webkit/WebKitGTK.java

@@ -90,6 +90,9 @@ public class WebKitGTK extends C {
 	public static final int WEBKIT_USER_SCRIPT_INJECT_AT_DOCUMENT_START = 0;
 	public static final int WEBKIT_USER_CONTENT_INJECT_TOP_FRAME = 1;
 
+	public static final int G_MAXUINT = 65535;
+	public static final int WEBKIT_FIND_OPTIONS_WRAP_AROUND = 1 << 4;
+
 	/** Signals */
 
 	// Authentication.