bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/Link.java - platform/eclipse.platform.swt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2016 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *     Conrad Groth - Bug 401015 - [CSS] Add support for styling hyperlinks in Links
  *******************************************************************************/
 package org.eclipse.swt.widgets;

 import java.util.*;

 import org.eclipse.swt.*;
 import org.eclipse.swt.events.*;
 import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.internal.*;
 import org.eclipse.swt.internal.win32.*;

 /**
  * Instances of this class represent a selectable
  * user interface object that displays a text with
  * links.
  * <dl>
  * <dt><b>Styles:</b></dt>
  * <dd>(none)</dd>
  * <dt><b>Events:</b></dt>
  * <dd>Selection</dd>
  * </dl>
  * <p>
  * IMPORTANT: This class is <em>not</em> intended to be subclassed.
  * </p>
  *
  * @see <a href="http://www.eclipse.org/swt/snippets/#link">Link snippets</a>
  * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a>
  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
  *
  * @since 3.1
  * @noextend This class is not intended to be subclassed by clients.
  */
 public class Link extends Control {
 	String text;
 	int linkForeground = -1;
 	String [] ids;
 	char [] mnemonics;
 	static final long LinkProc;
 	static final TCHAR LinkClass = new TCHAR (0, OS.WC_LINK, true);
 	static {
 		WNDCLASS lpWndClass = new WNDCLASS ();
 		OS.GetClassInfo (0, LinkClass, lpWndClass);
 		LinkProc = lpWndClass.lpfnWndProc;
 		/*
 		* Feature in Windows.  The SysLink window class
 		* does not include CS_DBLCLKS.  This means that these
 		* controls will not get double click messages such as
 		* WM_LBUTTONDBLCLK.  The fix is to register a new
 		* window class with CS_DBLCLKS.
 		*
 		* NOTE:  Screen readers look for the exact class name
 		* of the control in order to provide the correct kind
 		* of assistance.  Therefore, it is critical that the
 		* new window class have the same name.  It is possible
 		* to register a local window class with the same name
 		* as a global class.  Since bits that affect the class
 		* are being changed, it is possible that other native
 		* code, other than SWT, could create a control with
 		* this class name, and fail unexpectedly.
 		*/
 		lpWndClass.hInstance = OS.GetModuleHandle (null);
 		lpWndClass.style &= ~OS.CS_GLOBALCLASS;
 		lpWndClass.style |= OS.CS_DBLCLKS;
 		OS.RegisterClass (LinkClass, lpWndClass);
 	}

 /**
  * Constructs a new instance of this class given its parent
  * and a style value describing its behavior and appearance.
  * <p>
  * The style value is either one of the style constants defined in
  * class <code>SWT</code> which is applicable to instances of this
  * class, or must be built by <em>bitwise OR</em>'ing together
  * (that is, using the <code>int</code> "|" operator) two or more
  * of those <code>SWT</code> style constants. The class description
  * lists the style constants that are applicable to the class.
  * Style bits are also inherited from superclasses.
  * </p>
  *
  * @param parent a composite control which will be the parent of the new instance (cannot be null)
  * @param style the style of control to construct
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
  *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
  * </ul>
  *
  * @see Widget#checkSubclass
  * @see Widget#getStyle
  */
 public Link (Composite parent, int style) {
 	super (parent, style);
 }

 /**
  * Adds the listener to the collection of listeners who will
  * be notified when the control is selected by the user, by sending
  * it one of the messages defined in the <code>SelectionListener</code>
  * interface.
  * <p>
  * <code>widgetSelected</code> is called when the control is selected by the user.
  * <code>widgetDefaultSelected</code> is not called.
  * </p>
  *
  * @param listener the listener which should be notified
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  *
  * @see SelectionListener
  * @see #removeSelectionListener
  * @see SelectionEvent
  */
 public void addSelectionListener (SelectionListener listener) {
 	checkWidget ();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	TypedListener typedListener = new TypedListener (listener);
 	addListener (SWT.Selection, typedListener);
 	addListener (SWT.DefaultSelection, typedListener);
 }

 @Override
 long callWindowProc (long hwnd, int msg, long wParam, long lParam) {
 	if (handle == 0) return 0;
 	/*
 	* Feature in Windows.  By convention, native Windows controls
 	* check for a non-NULL wParam, assume that it is an HDC and
 	* paint using that device.  The SysLink control does not.
 	* The fix is to check for an HDC and use WM_PRINTCLIENT.
 	*/
 	switch (msg) {
 		case OS.WM_PAINT:
 			if (wParam != 0) {
 				OS.SendMessage (hwnd, OS.WM_PRINTCLIENT, wParam, 0);
 				return 0;
 			}
 			break;
 	}
 	return OS.CallWindowProc (LinkProc, hwnd, msg, wParam, lParam);
 }

 @Override
 Point computeSizeInPixels (int wHint, int hHint, boolean changed) {
 	checkWidget ();
 	int width, height;
 	/*
 	 * When the text is empty, LM_GETIDEALSIZE returns zero width and height,
 	 * but SWT convention is to return zero width and line height.
 	 */
 	if (text.isEmpty()) {
 		long hDC = OS.GetDC (handle);
 		long newFont = OS.SendMessage (handle, OS.WM_GETFONT, 0, 0);
 		long oldFont = OS.SelectObject (hDC, newFont);
 		TEXTMETRIC lptm = new TEXTMETRIC ();
 		OS.GetTextMetrics (hDC, lptm);
 		width = 0;
 		height = lptm.tmHeight;
 		if (newFont != 0) OS.SelectObject (hDC, oldFont);
 		OS.ReleaseDC (handle, hDC);
 	} else {
 		SIZE size = new SIZE ();
 		int maxWidth = (wHint == SWT.DEFAULT) ? 0x7fffffff : wHint;
 		OS.SendMessage (handle, OS.LM_GETIDEALSIZE, maxWidth, size);
 		width = size.cx;
 		height = size.cy;
 	}
 	if (wHint != SWT.DEFAULT) width = wHint;
 	if (hHint != SWT.DEFAULT) height = hHint;
 	int border = getBorderWidthInPixels ();
 	width += border * 2;
 	height += border * 2;
 	return new Point (width, height);
 }

 @Override
 void createHandle () {
 	super.createHandle ();
 	state |= THEME_BACKGROUND;
 }

 @Override
 void createWidget () {
 	super.createWidget ();
 	text = "";
 	ids = new String[0];
 	mnemonics = new char[0];
 }

 @Override
 void enableWidget (boolean enabled) {
 	super.enableWidget (enabled);
 	/*
 	 * Feature in Windows.  SysLink32 control doesn't natively
 	 * provide disabled state. Emulate it with custom draw.
 	 */
 	OS.InvalidateRect (handle, null, true);
 }

 int getFocusItem () {
 	LITEM item = new LITEM ();
 	item.mask = OS.LIF_ITEMINDEX | OS.LIF_STATE;
 	item.stateMask = OS.LIS_FOCUSED;
 	while (OS.SendMessage (handle, OS.LM_GETITEM, 0, item) != 0) {
 		if ((item.state & OS.LIS_FOCUSED) != 0) {
 			return item.iLink;
 		}
 		item.iLink++;
 	}
 	return -1;
 }

 /**
  * Returns the link foreground color.
  *
  * @return the receiver's link foreground color.
  *
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  * @since 3.105
  */
 public Color getLinkForeground () {
 	checkWidget ();
 	if (linkForeground != -1) {
 		return Color.win32_new (display, linkForeground);
 	}
 	return Color.win32_new (display, OS.GetSysColor (OS.COLOR_HOTLIGHT));
 }

 @Override
 String getNameText () {
 	return getText ();
 }

 /**
  * Returns the receiver's text, which will be an empty
  * string if it has never been set.
  *
  * @return the receiver's text
  *
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public String getText () {
 	checkWidget ();
 	return text;
 }

 @Override
 boolean mnemonicHit (char key) {
 	char uckey = Character.toUpperCase (key);
 	for (int i = 0; i < mnemonics.length; i++) {
 		if (uckey == mnemonics[i]) {
 			return setFocus () && setFocusItem (i);
 		}
 	}
 	return false;
 }

 @Override
 boolean mnemonicMatch (char key) {
 	char uckey = Character.toUpperCase (key);
 	for (int i = 0; i < mnemonics.length; i++) {
 		if (uckey == mnemonics[i]) {
 			return true;
 		}
 	}
 	return false;
 }

 void parse (String string) {
 	int length = string.length ();
 	// The shortest link length is 7 characters (<a></a>).
 	ids = new String [length / 7];
 	mnemonics = new char [length / 7];
 	int index = 0, state = 0, linkIndex = 0;
 	int linkStart = 0, linkEnd = 0, refStart = 0, refEnd = 0;
 	char mnemonic = 0;
 	while (index < length) {
 		char c = Character.toLowerCase (string.charAt (index));
 		switch (state) {
 			case 0:
 				if (c == '<') {
 					state++;
 				} else if (c == '&') {
 					state = 16;
 				}
 				break;
 			case 1:
 				if (c == 'a') state++;
 				break;
 			case 2:
 				switch (c) {
 					case 'h':
 						state = 7;
 						break;
 					case '>':
 						linkStart = index  + 1;
 						state++;
 						break;
 					default:
 						if (Character.isWhitespace(c)) break;
 						else state = 13;
 				}
 				break;
 			case 3:
 				if (c == '<') {
 					linkEnd = index;
 					state++;
 				}
 				break;
 			case 4:
 				state = c == '/' ? state + 1 : 3;
 				break;
 			case 5:
 				state = c == 'a' ? state + 1 : 3;
 				break;
 			case 6:
 				if (c == '>') {
 					if (refStart == 0) {
 						refStart = linkStart;
 						refEnd = linkEnd;
 					}
 					ids [linkIndex] = string.substring(refStart, refEnd);
 					if (mnemonic != 0) {
 						mnemonics [linkIndex] = mnemonic;
 					}
 					linkIndex++;
 					linkStart = linkEnd = refStart = refEnd = mnemonic = 0;
 					state = 0;
 				} else {
 					state = 3;
 				}
 				break;
 			case 7:
 				state = c == 'r' ? state + 1 : 0;
 				break;
 			case 8:
 				state = c == 'e' ? state + 1 : 0;
 				break;
 			case 9:
 				state = c == 'f' ? state + 1 : 0;
 				break;
 			case 10:
 				state = c == '=' ? state + 1 : 0;
 				break;
 			case 11:
 				if (c == '"') {
 					state++;
 					refStart = index + 1;
 				} else {
 					state = 0;
 				}
 				break;
 			case 12:
 				if (c == '"') {
 					refEnd = index;
 					state = 2;
 				}
 				break;
 			case 13:
 				if (Character.isWhitespace (c)) {
 					state = 0;
 				} else if (c == '='){
 					state++;
 				}
 				break;
 			case 14:
 				state = c == '"' ? state + 1 : 0;
 				break;
 			case 15:
 				if (c == '"') state = 2;
 				break;
 			case 16:
 				if (c == '<') {
 					state = 1;
 				} else {
 					state = 0;
 					if (c != '&') mnemonic = Character.toUpperCase (c);
 				}
 				break;
 			default:
 				state = 0;
 				break;
 		}
 		index++;
 	}
 	ids = Arrays.copyOf(ids, linkIndex);
 	mnemonics = Arrays.copyOf(mnemonics, linkIndex);
 }

 @Override
 void releaseWidget () {
 	super.releaseWidget ();
 	ids = null;
 	mnemonics = null;
 	text = null;
 }

 /**
  * Removes the listener from the collection of listeners who will
  * be notified when the control is selected by the user.
  *
  * @param listener the listener which should no longer be notified
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  *
  * @see SelectionListener
  * @see #addSelectionListener
  */
 public void removeSelectionListener (SelectionListener listener) {
 	checkWidget ();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	if (eventTable == null) return;
 	eventTable.unhook (SWT.Selection, listener);
 	eventTable.unhook (SWT.DefaultSelection, listener);
 }

 boolean setFocusItem (int index) {
 	int bits = OS.GetWindowLong (handle, OS.GWL_STYLE);
 	LITEM item = new LITEM ();
 	item.mask = OS.LIF_ITEMINDEX | OS.LIF_STATE;
 	item.stateMask = OS.LIS_FOCUSED;
 	while (item.iLink < ids.length) {
 		if (item.iLink != index) OS.SendMessage (handle, OS.LM_SETITEM, 0, item);
 		item.iLink++;
 	}
 	item.iLink = index;
 	item.state = OS.LIS_FOCUSED;
 	long result = OS.SendMessage (handle, OS.LM_SETITEM, 0, item);

 	/* Feature in Windows. For some reason, setting the focus to
 	 * any item but first causes the control to clear the WS_TABSTOP
 	 * bit. The fix is always to reset the bit.
 	 */
 	OS.SetWindowLong (handle, OS.GWL_STYLE, bits);
 	return result != 0;
 }

 /**
  * Sets the link foreground color to the color specified
  * by the argument, or to the default system color for the link
  * if the argument is null.
  * <p>
  * Note: This operation is a hint and may be overridden by the platform.
  * </p>
  * @param color the new color (or null)
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  * @since 3.105
  */
 public void setLinkForeground (Color color) {
 	checkWidget ();
 	int pixel = -1;
 	if (color != null) {
 		if (color.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT);
 		pixel = color.handle;
 	}
 	if (pixel == linkForeground) return;
 	linkForeground = pixel;
 	OS.InvalidateRect (handle, null, true);
 }

 /**
  * Sets the receiver's text.
  * <p>
  * The string can contain both regular text and hyperlinks.  A hyperlink
  * is delimited by an anchor tag, &lt;a&gt; and &lt;/a&gt;.  Within an
  * anchor, a single HREF attribute is supported.  When a hyperlink is
  * selected, the text field of the selection event contains either the
  * text of the hyperlink or the value of its HREF, if one was specified.
  * In the rare case of identical hyperlinks within the same string, the
  * HREF attribute can be used to distinguish between them.  The string may
  * include the mnemonic character and line delimiters. The only delimiter
  * the HREF attribute supports is the quotation mark ("). Text containing
  * angle-bracket characters &lt; or &gt; may be escaped using \\, however
  * this operation is a hint and varies from platform to platform.
  * </p>
  * <p>
  * Mnemonics are indicated by an '&amp;' that causes the next
  * character to be the mnemonic. The receiver can have a
  * mnemonic in the text preceding each link. When the user presses a
  * key sequence that matches the mnemonic, focus is assigned
  * to the link that follows the text. Mnemonics in links and in
  * the trailing text are ignored. On most platforms,
  * the mnemonic appears underlined but may be emphasised in a
  * platform specific manner.  The mnemonic indicator character
  * '&amp;' can be escaped by doubling it in the string, causing
  * a single '&amp;' to be displayed.
  * </p>
  *
  * @param string the new text
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the text is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public void setText (String string) {
 	checkWidget ();
 	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
 	if (string.equals (text)) return;
 	text = string;
 	if ((state & HAS_AUTO_DIRECTION) != 0) {
 		updateTextDirection (AUTO_TEXT_DIRECTION);
 	}
 	TCHAR buffer = new TCHAR (getCodePage (), string, true);
 	OS.SetWindowText (handle, buffer);
 	parse(string);
 }

 @Override
 int resolveTextDirection() {
 	return BidiUtil.resolveTextDirection(text);
 }

 @Override
 boolean updateTextDirection(int textDirection) {
 	if (super.updateTextDirection(textDirection)) {
 		int flags = SWT.RIGHT_TO_LEFT | SWT.LEFT_TO_RIGHT;
 		style &= ~SWT.MIRRORED;
 		style &= ~flags;
 		style |= textDirection & flags;
 		updateOrientation ();
 		checkMirrored ();
 		return true;
 	}
 	return false;
 }

 @Override
 int widgetStyle () {
 	int bits = super.widgetStyle ();
 	return bits | OS.WS_TABSTOP;
 }

 @Override
 TCHAR windowClass () {
 	return LinkClass;
 }

 @Override
 long windowProc () {
 	return LinkProc;
 }

 @Override
 LRESULT WM_CHAR (long wParam, long lParam) {
 	LRESULT result = super.WM_CHAR (wParam, lParam);
 	if (result != null) return result;
 	switch ((int)wParam) {
 		case ' ':
 		case SWT.CR:
 		case SWT.TAB:
 			/*
 			* NOTE: Call the window proc with WM_KEYDOWN rather than WM_CHAR
 			* so that the key that was ignored during WM_KEYDOWN is processed.
 			* This allows the application to cancel an operation that is normally
 			* performed in WM_KEYDOWN from WM_CHAR.
 			*/
 			long code = callWindowProc (handle, OS.WM_KEYDOWN, wParam, lParam);
 			return new LRESULT (code);
 	}
 	return result;
 }

 @Override
 LRESULT WM_GETDLGCODE (long wParam, long lParam) {
 	long code = callWindowProc (handle, OS.WM_GETDLGCODE, wParam, lParam);
 	int count = ids.length;
 	if (count == 0) {
 		code |= OS.DLGC_STATIC;
 	} else if (count > 1) {
 		int limit = (OS.GetKeyState (OS.VK_SHIFT) < 0) ? 0 : count - 1;
 		if (getFocusItem() != limit) {
 			code |= OS.DLGC_WANTTAB;
 		}
 	}
 	return new LRESULT (code);
 }

 @Override
 LRESULT WM_KEYDOWN (long wParam, long lParam) {
 	LRESULT result = super.WM_KEYDOWN (wParam, lParam);
 	if (result != null) return result;
 	switch ((int)wParam) {
 		case OS.VK_SPACE:
 		case OS.VK_RETURN:
 		case OS.VK_TAB:
 			/*
 			* Ensure that the window proc does not process VK_SPACE,
 			* VK_RETURN or VK_TAB so that it can be handled in WM_CHAR.
 			* This allows the application to cancel an operation that
 			* is normally performed in WM_KEYDOWN from WM_CHAR.
 			*/
 			return LRESULT.ZERO;
 	}
 	return result;
 }

 @Override
 LRESULT WM_KILLFOCUS (long wParam, long lParam) {
 	int focusItem = getFocusItem();
 	LRESULT result = super.WM_KILLFOCUS(wParam, lParam);
 	if (focusItem != -1) setFocusItem(focusItem);
 	return result;
 }

 @Override
 LRESULT WM_NCHITTEST (long wParam, long lParam) {
 	LRESULT result = super.WM_NCHITTEST (wParam, lParam);
 	if (result != null) return result;

 	/*
 	* Feature in Windows. For WM_NCHITTEST, the Syslink window proc
 	* returns HTTRANSPARENT when mouse is over plain text. As a result,
 	* mouse events are not delivered. The fix is to always return HTCLIENT.
 	*/
 	return new LRESULT (OS.HTCLIENT);
 }

 @Override
 LRESULT WM_SETCURSOR(long wParam, long lParam) {
 	LRESULT result = super.WM_SETCURSOR (wParam, lParam);
 	if (result != null) return result;
 	long fDone = callWindowProc (handle, OS.WM_SETCURSOR, wParam, lParam);
 	/* Take responsibility for cursor over plain text after overriding WM_NCHITTEST. */
 	if (fDone == 0) OS.DefWindowProc (handle, OS.WM_SETCURSOR, wParam, lParam);
 	return LRESULT.ONE;
 }

 @Override
 LRESULT WM_SETFOCUS (long wParam, long lParam) {
 	/*
 	* Feature in Windows. Upon receiving focus, SysLink control
 	* always activates the first link. This leads to surprising
 	* behavior in multi-link controls.
 	*/
 	if (ids.length > 1) {
 		if (OS.GetKeyState (OS.VK_TAB) < 0) {
 			boolean shift = OS.GetKeyState (OS.VK_SHIFT) < 0;
 			setFocusItem(shift ? ids.length - 1 : 0);
 		}
 	}
 	return super.WM_SETFOCUS (wParam, lParam);
 }

 @Override
 LRESULT wmNotifyChild (NMHDR hdr, long wParam, long lParam) {
 	switch (hdr.code) {
 		case OS.NM_RETURN:
 		case OS.NM_CLICK:
 			NMLINK item = new NMLINK ();
 			OS.MoveMemory (item, lParam, NMLINK.sizeof);
 			Event event = new Event ();
 			event.text = ids [item.iLink];
 			sendSelectionEvent (SWT.Selection, event, true);
 			break;
 		case OS.NM_CUSTOMDRAW:
 			NMCUSTOMDRAW nmcd = new NMCUSTOMDRAW ();
 			OS.MoveMemory (nmcd, lParam, NMCUSTOMDRAW.sizeof);
 			switch (nmcd.dwDrawStage) {
 				case OS.CDDS_PREPAINT:
 					if (!OS.IsWindowEnabled (handle) || linkForeground != -1) {
 						return new LRESULT(OS.CDRF_NOTIFYITEMDRAW);
 					}
 					break;
 				case OS.CDDS_ITEMPREPAINT:
 					/*
 					 * Feature in Windows.  SysLink32 control doesn't natively
 					 * provide disabled state. Emulate it with custom draw.
 					 */
 					if (!OS.IsWindowEnabled (handle)) {
 						OS.SetTextColor (nmcd.hdc, OS.GetSysColor (OS.COLOR_GRAYTEXT));
 					}
 					else if (linkForeground != -1 && nmcd.dwItemSpec != -1) {
 						OS.SetTextColor(nmcd.hdc, linkForeground);
 					}
 					break;
 			}
 			break;
 	}
 	return super.wmNotifyChild (hdr, wParam, lParam);
 }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2016 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	* Conrad Groth - Bug 401015 - [CSS] Add support for styling hyperlinks in Links
	*******************************************************************************/
	package org.eclipse.swt.widgets;

	import java.util.*;

	import org.eclipse.swt.*;
	import org.eclipse.swt.events.*;
	import org.eclipse.swt.graphics.*;
	import org.eclipse.swt.internal.*;
	import org.eclipse.swt.internal.win32.*;

	/**
	* Instances of this class represent a selectable
	* user interface object that displays a text with
	* links.
	* <dl>
	* <dt><b>Styles:</b></dt>
	* <dd>(none)</dd>
	* <dt><b>Events:</b></dt>
	* <dd>Selection</dd>
	* </dl>
	* <p>
	* IMPORTANT: This class is <em>not</em> intended to be subclassed.
	* </p>
	*
	* @see <a href="http://www.eclipse.org/swt/snippets/#link">Link snippets</a>
	* @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a>
	* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
	*
	* @since 3.1
	* @noextend This class is not intended to be subclassed by clients.
	*/
	public class Link extends Control {
	String text;
	int linkForeground = -1;
	String [] ids;
	char [] mnemonics;
	static final long LinkProc;
	static final TCHAR LinkClass = new TCHAR (0, OS.WC_LINK, true);
	static {
	WNDCLASS lpWndClass = new WNDCLASS ();
	OS.GetClassInfo (0, LinkClass, lpWndClass);
	LinkProc = lpWndClass.lpfnWndProc;
	/*
	* Feature in Windows. The SysLink window class
	* does not include CS_DBLCLKS. This means that these
	* controls will not get double click messages such as
	* WM_LBUTTONDBLCLK. The fix is to register a new
	* window class with CS_DBLCLKS.
	*
	* NOTE: Screen readers look for the exact class name
	* of the control in order to provide the correct kind
	* of assistance. Therefore, it is critical that the
	* new window class have the same name. It is possible
	* to register a local window class with the same name
	* as a global class. Since bits that affect the class
	* are being changed, it is possible that other native
	* code, other than SWT, could create a control with
	* this class name, and fail unexpectedly.
	*/
	lpWndClass.hInstance = OS.GetModuleHandle (null);
	lpWndClass.style &= ~OS.CS_GLOBALCLASS;
	lpWndClass.style \|= OS.CS_DBLCLKS;
	OS.RegisterClass (LinkClass, lpWndClass);
	}

	/**
	* Constructs a new instance of this class given its parent
	* and a style value describing its behavior and appearance.
	* <p>
	* The style value is either one of the style constants defined in
	* class <code>SWT</code> which is applicable to instances of this
	* class, or must be built by <em>bitwise OR</em>'ing together
	* (that is, using the <code>int</code> "\|" operator) two or more
	* of those <code>SWT</code> style constants. The class description
	* lists the style constants that are applicable to the class.
	* Style bits are also inherited from superclasses.
	* </p>
	*
	* @param parent a composite control which will be the parent of the new instance (cannot be null)
	* @param style the style of control to construct
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
	* <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
	* </ul>
	*
	* @see Widget#checkSubclass
	* @see Widget#getStyle
	*/
	public Link (Composite parent, int style) {
	super (parent, style);
	}

	/**
	* Adds the listener to the collection of listeners who will
	* be notified when the control is selected by the user, by sending
	* it one of the messages defined in the <code>SelectionListener</code>
	* interface.
	* <p>
	* <code>widgetSelected</code> is called when the control is selected by the user.
	* <code>widgetDefaultSelected</code> is not called.
	* </p>
	*
	* @param listener the listener which should be notified
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*
	* @see SelectionListener
	* @see #removeSelectionListener
	* @see SelectionEvent
	*/
	public void addSelectionListener (SelectionListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Selection, typedListener);
	addListener (SWT.DefaultSelection, typedListener);
	}

	@Override
	long callWindowProc (long hwnd, int msg, long wParam, long lParam) {
	if (handle == 0) return 0;
	/*
	* Feature in Windows. By convention, native Windows controls
	* check for a non-NULL wParam, assume that it is an HDC and
	* paint using that device. The SysLink control does not.
	* The fix is to check for an HDC and use WM_PRINTCLIENT.
	*/
	switch (msg) {
	case OS.WM_PAINT:
	if (wParam != 0) {
	OS.SendMessage (hwnd, OS.WM_PRINTCLIENT, wParam, 0);
	return 0;
	}
	break;
	}
	return OS.CallWindowProc (LinkProc, hwnd, msg, wParam, lParam);
	}

	@Override
	Point computeSizeInPixels (int wHint, int hHint, boolean changed) {
	checkWidget ();
	int width, height;
	/*
	* When the text is empty, LM_GETIDEALSIZE returns zero width and height,
	* but SWT convention is to return zero width and line height.
	*/
	if (text.isEmpty()) {
	long hDC = OS.GetDC (handle);
	long newFont = OS.SendMessage (handle, OS.WM_GETFONT, 0, 0);
	long oldFont = OS.SelectObject (hDC, newFont);
	TEXTMETRIC lptm = new TEXTMETRIC ();
	OS.GetTextMetrics (hDC, lptm);
	width = 0;
	height = lptm.tmHeight;
	if (newFont != 0) OS.SelectObject (hDC, oldFont);
	OS.ReleaseDC (handle, hDC);
	} else {
	SIZE size = new SIZE ();
	int maxWidth = (wHint == SWT.DEFAULT) ? 0x7fffffff : wHint;
	OS.SendMessage (handle, OS.LM_GETIDEALSIZE, maxWidth, size);
	width = size.cx;
	height = size.cy;
	}
	if (wHint != SWT.DEFAULT) width = wHint;
	if (hHint != SWT.DEFAULT) height = hHint;
	int border = getBorderWidthInPixels ();
	width += border * 2;
	height += border * 2;
	return new Point (width, height);
	}

	@Override
	void createHandle () {
	super.createHandle ();
	state \|= THEME_BACKGROUND;
	}

	@Override
	void createWidget () {
	super.createWidget ();
	text = "";
	ids = new String[0];
	mnemonics = new char[0];
	}

	@Override
	void enableWidget (boolean enabled) {
	super.enableWidget (enabled);
	/*
	* Feature in Windows. SysLink32 control doesn't natively
	* provide disabled state. Emulate it with custom draw.
	*/
	OS.InvalidateRect (handle, null, true);
	}

	int getFocusItem () {
	LITEM item = new LITEM ();
	item.mask = OS.LIF_ITEMINDEX \| OS.LIF_STATE;
	item.stateMask = OS.LIS_FOCUSED;
	while (OS.SendMessage (handle, OS.LM_GETITEM, 0, item) != 0) {
	if ((item.state & OS.LIS_FOCUSED) != 0) {
	return item.iLink;
	}
	item.iLink++;
	}
	return -1;
	}

	/**
	* Returns the link foreground color.
	*
	* @return the receiver's link foreground color.
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	* @since 3.105
	*/
	public Color getLinkForeground () {
	checkWidget ();
	if (linkForeground != -1) {
	return Color.win32_new (display, linkForeground);
	}
	return Color.win32_new (display, OS.GetSysColor (OS.COLOR_HOTLIGHT));
	}

	@Override
	String getNameText () {
	return getText ();
	}

	/**
	* Returns the receiver's text, which will be an empty
	* string if it has never been set.
	*
	* @return the receiver's text
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public String getText () {
	checkWidget ();
	return text;
	}

	@Override
	boolean mnemonicHit (char key) {
	char uckey = Character.toUpperCase (key);
	for (int i = 0; i < mnemonics.length; i++) {
	if (uckey == mnemonics[i]) {
	return setFocus () && setFocusItem (i);
	}
	}
	return false;
	}

	@Override
	boolean mnemonicMatch (char key) {
	char uckey = Character.toUpperCase (key);
	for (int i = 0; i < mnemonics.length; i++) {
	if (uckey == mnemonics[i]) {
	return true;
	}
	}
	return false;
	}

	void parse (String string) {
	int length = string.length ();
	// The shortest link length is 7 characters (<a></a>).
	ids = new String [length / 7];
	mnemonics = new char [length / 7];
	int index = 0, state = 0, linkIndex = 0;
	int linkStart = 0, linkEnd = 0, refStart = 0, refEnd = 0;
	char mnemonic = 0;
	while (index < length) {
	char c = Character.toLowerCase (string.charAt (index));
	switch (state) {
	case 0:
	if (c == '<') {
	state++;
	} else if (c == '&') {
	state = 16;
	}
	break;
	case 1:
	if (c == 'a') state++;
	break;
	case 2:
	switch (c) {
	case 'h':
	state = 7;
	break;
	case '>':
	linkStart = index + 1;
	state++;
	break;
	default:
	if (Character.isWhitespace(c)) break;
	else state = 13;
	}
	break;
	case 3:
	if (c == '<') {
	linkEnd = index;
	state++;
	}
	break;
	case 4:
	state = c == '/' ? state + 1 : 3;
	break;
	case 5:
	state = c == 'a' ? state + 1 : 3;
	break;
	case 6:
	if (c == '>') {
	if (refStart == 0) {
	refStart = linkStart;
	refEnd = linkEnd;
	}
	ids [linkIndex] = string.substring(refStart, refEnd);
	if (mnemonic != 0) {
	mnemonics [linkIndex] = mnemonic;
	}
	linkIndex++;
	linkStart = linkEnd = refStart = refEnd = mnemonic = 0;
	state = 0;
	} else {
	state = 3;
	}
	break;
	case 7:
	state = c == 'r' ? state + 1 : 0;
	break;
	case 8:
	state = c == 'e' ? state + 1 : 0;
	break;
	case 9:
	state = c == 'f' ? state + 1 : 0;
	break;
	case 10:
	state = c == '=' ? state + 1 : 0;
	break;
	case 11:
	if (c == '"') {
	state++;
	refStart = index + 1;
	} else {
	state = 0;
	}
	break;
	case 12:
	if (c == '"') {
	refEnd = index;
	state = 2;
	}
	break;
	case 13:
	if (Character.isWhitespace (c)) {
	state = 0;
	} else if (c == '='){
	state++;
	}
	break;
	case 14:
	state = c == '"' ? state + 1 : 0;
	break;
	case 15:
	if (c == '"') state = 2;
	break;
	case 16:
	if (c == '<') {
	state = 1;
	} else {
	state = 0;
	if (c != '&') mnemonic = Character.toUpperCase (c);
	}
	break;
	default:
	state = 0;
	break;
	}
	index++;
	}
	ids = Arrays.copyOf(ids, linkIndex);
	mnemonics = Arrays.copyOf(mnemonics, linkIndex);
	}

	@Override
	void releaseWidget () {
	super.releaseWidget ();
	ids = null;
	mnemonics = null;
	text = null;
	}

	/**
	* Removes the listener from the collection of listeners who will
	* be notified when the control is selected by the user.
	*
	* @param listener the listener which should no longer be notified
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*
	* @see SelectionListener
	* @see #addSelectionListener
	*/
	public void removeSelectionListener (SelectionListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Selection, listener);
	eventTable.unhook (SWT.DefaultSelection, listener);
	}

	boolean setFocusItem (int index) {
	int bits = OS.GetWindowLong (handle, OS.GWL_STYLE);
	LITEM item = new LITEM ();
	item.mask = OS.LIF_ITEMINDEX \| OS.LIF_STATE;
	item.stateMask = OS.LIS_FOCUSED;
	while (item.iLink < ids.length) {
	if (item.iLink != index) OS.SendMessage (handle, OS.LM_SETITEM, 0, item);
	item.iLink++;
	}
	item.iLink = index;
	item.state = OS.LIS_FOCUSED;
	long result = OS.SendMessage (handle, OS.LM_SETITEM, 0, item);

	/* Feature in Windows. For some reason, setting the focus to
	* any item but first causes the control to clear the WS_TABSTOP
	* bit. The fix is always to reset the bit.
	*/
	OS.SetWindowLong (handle, OS.GWL_STYLE, bits);
	return result != 0;
	}

	/**
	* Sets the link foreground color to the color specified
	* by the argument, or to the default system color for the link
	* if the argument is null.
	* <p>
	* Note: This operation is a hint and may be overridden by the platform.
	* </p>
	* @param color the new color (or null)
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_INVALID_ARGUMENT - if the argument has been disposed</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	* @since 3.105
	*/
	public void setLinkForeground (Color color) {
	checkWidget ();
	int pixel = -1;
	if (color != null) {
	if (color.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT);
	pixel = color.handle;
	}
	if (pixel == linkForeground) return;
	linkForeground = pixel;
	OS.InvalidateRect (handle, null, true);
	}

	/**
	* Sets the receiver's text.
	* <p>
	* The string can contain both regular text and hyperlinks. A hyperlink
	* is delimited by an anchor tag, <a> and </a>. Within an
	* anchor, a single HREF attribute is supported. When a hyperlink is
	* selected, the text field of the selection event contains either the
	* text of the hyperlink or the value of its HREF, if one was specified.
	* In the rare case of identical hyperlinks within the same string, the
	* HREF attribute can be used to distinguish between them. The string may
	* include the mnemonic character and line delimiters. The only delimiter
	* the HREF attribute supports is the quotation mark ("). Text containing
	* angle-bracket characters < or > may be escaped using \\, however
	* this operation is a hint and varies from platform to platform.
	* </p>
	* <p>
	* Mnemonics are indicated by an '&' that causes the next
	* character to be the mnemonic. The receiver can have a
	* mnemonic in the text preceding each link. When the user presses a
	* key sequence that matches the mnemonic, focus is assigned
	* to the link that follows the text. Mnemonics in links and in
	* the trailing text are ignored. On most platforms,
	* the mnemonic appears underlined but may be emphasised in a
	* platform specific manner. The mnemonic indicator character
	* '&' can be escaped by doubling it in the string, causing
	* a single '&' to be displayed.
	* </p>
	*
	* @param string the new text
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the text is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setText (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (string.equals (text)) return;
	text = string;
	if ((state & HAS_AUTO_DIRECTION) != 0) {
	updateTextDirection (AUTO_TEXT_DIRECTION);
	}
	TCHAR buffer = new TCHAR (getCodePage (), string, true);
	OS.SetWindowText (handle, buffer);
	parse(string);
	}

	@Override
	int resolveTextDirection() {
	return BidiUtil.resolveTextDirection(text);
	}

	@Override
	boolean updateTextDirection(int textDirection) {
	if (super.updateTextDirection(textDirection)) {
	int flags = SWT.RIGHT_TO_LEFT \| SWT.LEFT_TO_RIGHT;
	style &= ~SWT.MIRRORED;
	style &= ~flags;
	style \|= textDirection & flags;
	updateOrientation ();
	checkMirrored ();
	return true;
	}
	return false;
	}

	@Override
	int widgetStyle () {
	int bits = super.widgetStyle ();
	return bits \| OS.WS_TABSTOP;
	}

	@Override
	TCHAR windowClass () {
	return LinkClass;
	}

	@Override
	long windowProc () {
	return LinkProc;
	}

	@Override
	LRESULT WM_CHAR (long wParam, long lParam) {
	LRESULT result = super.WM_CHAR (wParam, lParam);
	if (result != null) return result;
	switch ((int)wParam) {
	case ' ':
	case SWT.CR:
	case SWT.TAB:
	/*
	* NOTE: Call the window proc with WM_KEYDOWN rather than WM_CHAR
	* so that the key that was ignored during WM_KEYDOWN is processed.
	* This allows the application to cancel an operation that is normally
	* performed in WM_KEYDOWN from WM_CHAR.
	*/
	long code = callWindowProc (handle, OS.WM_KEYDOWN, wParam, lParam);
	return new LRESULT (code);
	}
	return result;
	}

	@Override
	LRESULT WM_GETDLGCODE (long wParam, long lParam) {
	long code = callWindowProc (handle, OS.WM_GETDLGCODE, wParam, lParam);
	int count = ids.length;
	if (count == 0) {
	code \|= OS.DLGC_STATIC;
	} else if (count > 1) {
	int limit = (OS.GetKeyState (OS.VK_SHIFT) < 0) ? 0 : count - 1;
	if (getFocusItem() != limit) {
	code \|= OS.DLGC_WANTTAB;
	}
	}
	return new LRESULT (code);
	}

	@Override
	LRESULT WM_KEYDOWN (long wParam, long lParam) {
	LRESULT result = super.WM_KEYDOWN (wParam, lParam);
	if (result != null) return result;
	switch ((int)wParam) {
	case OS.VK_SPACE:
	case OS.VK_RETURN:
	case OS.VK_TAB:
	/*
	* Ensure that the window proc does not process VK_SPACE,
	* VK_RETURN or VK_TAB so that it can be handled in WM_CHAR.
	* This allows the application to cancel an operation that
	* is normally performed in WM_KEYDOWN from WM_CHAR.
	*/
	return LRESULT.ZERO;
	}
	return result;
	}

	@Override
	LRESULT WM_KILLFOCUS (long wParam, long lParam) {
	int focusItem = getFocusItem();
	LRESULT result = super.WM_KILLFOCUS(wParam, lParam);
	if (focusItem != -1) setFocusItem(focusItem);
	return result;
	}

	@Override
	LRESULT WM_NCHITTEST (long wParam, long lParam) {
	LRESULT result = super.WM_NCHITTEST (wParam, lParam);
	if (result != null) return result;

	/*
	* Feature in Windows. For WM_NCHITTEST, the Syslink window proc
	* returns HTTRANSPARENT when mouse is over plain text. As a result,
	* mouse events are not delivered. The fix is to always return HTCLIENT.
	*/
	return new LRESULT (OS.HTCLIENT);
	}

	@Override
	LRESULT WM_SETCURSOR(long wParam, long lParam) {
	LRESULT result = super.WM_SETCURSOR (wParam, lParam);
	if (result != null) return result;
	long fDone = callWindowProc (handle, OS.WM_SETCURSOR, wParam, lParam);
	/* Take responsibility for cursor over plain text after overriding WM_NCHITTEST. */
	if (fDone == 0) OS.DefWindowProc (handle, OS.WM_SETCURSOR, wParam, lParam);
	return LRESULT.ONE;
	}

	@Override
	LRESULT WM_SETFOCUS (long wParam, long lParam) {
	/*
	* Feature in Windows. Upon receiving focus, SysLink control
	* always activates the first link. This leads to surprising
	* behavior in multi-link controls.
	*/
	if (ids.length > 1) {
	if (OS.GetKeyState (OS.VK_TAB) < 0) {
	boolean shift = OS.GetKeyState (OS.VK_SHIFT) < 0;
	setFocusItem(shift ? ids.length - 1 : 0);
	}
	}
	return super.WM_SETFOCUS (wParam, lParam);
	}

	@Override
	LRESULT wmNotifyChild (NMHDR hdr, long wParam, long lParam) {
	switch (hdr.code) {
	case OS.NM_RETURN:
	case OS.NM_CLICK:
	NMLINK item = new NMLINK ();
	OS.MoveMemory (item, lParam, NMLINK.sizeof);
	Event event = new Event ();
	event.text = ids [item.iLink];
	sendSelectionEvent (SWT.Selection, event, true);
	break;
	case OS.NM_CUSTOMDRAW:
	NMCUSTOMDRAW nmcd = new NMCUSTOMDRAW ();
	OS.MoveMemory (nmcd, lParam, NMCUSTOMDRAW.sizeof);
	switch (nmcd.dwDrawStage) {
	case OS.CDDS_PREPAINT:
	if (!OS.IsWindowEnabled (handle) \|\| linkForeground != -1) {
	return new LRESULT(OS.CDRF_NOTIFYITEMDRAW);
	}
	break;
	case OS.CDDS_ITEMPREPAINT:
	/*
	* Feature in Windows. SysLink32 control doesn't natively
	* provide disabled state. Emulate it with custom draw.
	*/
	if (!OS.IsWindowEnabled (handle)) {
	OS.SetTextColor (nmcd.hdc, OS.GetSysColor (OS.COLOR_GRAYTEXT));
	}
	else if (linkForeground != -1 && nmcd.dwItemSpec != -1) {
	OS.SetTextColor(nmcd.hdc, linkForeground);
	}
	break;
	}
	break;
	}
	return super.wmNotifyChild (hdr, wParam, lParam);
	}
	}