root/dwt/widgets/Link.d

/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwt.widgets.Link;

import dwt.DWT;
import dwt.DWTException;
import dwt.accessibility.ACC;
import dwt.accessibility.Accessible;
import dwt.accessibility.AccessibleAdapter;
import dwt.accessibility.AccessibleControlAdapter;
import dwt.accessibility.AccessibleControlEvent;
import dwt.accessibility.AccessibleEvent;
import dwt.events.SelectionEvent;
import dwt.events.SelectionListener;
import dwt.graphics.Color;
import dwt.graphics.Font;
import dwt.graphics.GC;
import dwt.graphics.GCData;
import dwt.graphics.Point;
import dwt.graphics.RGB;
import dwt.graphics.Rectangle;
import dwt.graphics.TextLayout;
import dwt.graphics.TextStyle;
import dwt.internal.win32.OS;

import dwt.widgets.Control;
import dwt.widgets.Composite;
import dwt.widgets.TypedListener;
import dwt.widgets.Event;

import dwt.dwthelper.utils;

static import tango.text.Text;
alias tango.text.Text.Text!(char) StringBuffer;

/**
 * Instances of this class represent a selectable
 * user interface object that displays a text with
 * links.
 * <p>
 * <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">DWT Example: ControlExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 * 
 * @since 3.1
 */
public class Link : Control {

    alias Control.computeSize computeSize;
    alias Control.windowProc windowProc;

    String text;
    TextLayout layout;
    Color linkColor, disabledColor;
    Point [] offsets;
    Point selection;
    String [] ids;
    int [] mnemonics;
    int focusIndex, mouseDownIndex;
    HFONT font;
    static /+const+/ RGB LINK_FOREGROUND;
    static /+const+/ WNDPROC LinkProc;
    static const TCHAR[] LinkClass = OS.WC_LINK;

    private static bool static_this_completed = false;
    private static void static_this() {
        if( static_this_completed ){
            return;
        }
        synchronized {
            if( static_this_completed ){
                return;
            }
            LINK_FOREGROUND = new RGB (0, 51, 153);
            if (OS.COMCTL32_MAJOR >= 6) {
                WNDCLASS lpWndClass;
                OS.GetClassInfo (null, LinkClass.ptr, &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 DWT, could create a control with
            * this class name, and fail unexpectedly.
            */
            auto hInstance = OS.GetModuleHandle (null);
            auto hHeap = OS.GetProcessHeap ();
            lpWndClass.hInstance = hInstance;
            lpWndClass.style &= ~OS.CS_GLOBALCLASS;
            lpWndClass.style |= OS.CS_DBLCLKS;
            int byteCount = LinkClass.length * TCHAR.sizeof;
            auto lpszClassName = cast(TCHAR*) OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
            OS.MoveMemory (lpszClassName, LinkClass.ptr, byteCount);
            lpWndClass.lpszClassName = lpszClassName;
            OS.RegisterClass (&lpWndClass);
            OS.HeapFree (hHeap, 0, lpszClassName);
            } else {
                LinkProc = null;
            }
            static_this_completed = true;
        }
    }

/**
 * 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>DWT</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>DWT</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 DWTException <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 this (Composite parent, int style) {
    static_this();
    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 DWTException <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 is null) error (DWT.ERROR_NULL_ARGUMENT);
    TypedListener typedListener = new TypedListener (listener);
    addListener (DWT.Selection, typedListener);
    addListener (DWT.DefaultSelection, typedListener);
}

override int callWindowProc (HWND hwnd, int msg, int wParam, int lParam) {
    if (handle is null) return 0;
    if (LinkProc !is null) {
        /*
        * 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 !is 0) {
                    OS.SendMessage (hwnd, OS.WM_PRINTCLIENT, wParam, 0);
                    return 0;
                }
                break;
            default:
        }
        return OS.CallWindowProc (LinkProc, hwnd, msg, wParam, lParam);
    }
    return OS.DefWindowProc (hwnd, msg, wParam, lParam);
}

override public Point computeSize (int wHint, int hHint, bool changed) {
    checkWidget ();
    if (wHint !is DWT.DEFAULT && wHint < 0) wHint = 0;
    if (hHint !is DWT.DEFAULT && hHint < 0) hHint = 0;
    int width, height;
    if (OS.COMCTL32_MAJOR >= 6) {
        auto hDC = OS.GetDC (handle);
        auto newFont = cast(HFONT) OS.SendMessage (handle, OS.WM_GETFONT, 0, 0);
        auto oldFont = OS.SelectObject (hDC, newFont);
        if (text.length > 0) {
            TCHAR[] buffer = StrToTCHARs (getCodePage (), parse (text));
            RECT rect;
            int flags = OS.DT_CALCRECT | OS.DT_NOPREFIX;
            if (wHint !is DWT.DEFAULT) {
                flags |= OS.DT_WORDBREAK;
                rect.right = wHint;
            }
            OS.DrawText (hDC, buffer.ptr, buffer.length, &rect, flags);
            width = rect.right - rect.left;
            height = rect.bottom;
        } else {
            TEXTMETRIC lptm;
            OS.GetTextMetrics (hDC, &lptm);
            width = 0;
            height = lptm.tmHeight;
        }
        if (newFont !is null) OS.SelectObject (hDC, oldFont);
        OS.ReleaseDC (handle, hDC);
    } else {
        int layoutWidth = layout.getWidth ();
        //TEMPORARY CODE
        if (wHint is 0) {
            layout.setWidth (1);
            Rectangle rect = layout.getBounds ();
            width = 0;
            height = rect.height;
        } else {
            layout.setWidth (wHint);
            Rectangle rect = layout.getBounds ();
            width = rect.width;
            height = rect.height;
        }
        layout.setWidth (layoutWidth);
    }
    if (wHint !is DWT.DEFAULT) width = wHint;
    if (hHint !is DWT.DEFAULT) height = hHint;
    int border = getBorderWidth ();
    width += border * 2;
    height += border * 2;
    return new Point (width, height);
}

override void createHandle () {
    super.createHandle ();
    state |= THEME_BACKGROUND;
    if (OS.COMCTL32_MAJOR < 6) {
        layout = new TextLayout (display);
        if (!OS.IsWinCE && OS.WIN32_VERSION >= OS.VERSION (4, 10)) {
            linkColor = Color.win32_new (display, OS.GetSysColor (OS.COLOR_HOTLIGHT));
        } else {
            linkColor = new Color (display, LINK_FOREGROUND);
        }
        disabledColor = Color.win32_new (display, OS.GetSysColor (OS.COLOR_GRAYTEXT));
        offsets = new Point [0];
        ids = new String [0];
        mnemonics = new int [0];
        selection = new Point (-1, -1);
        focusIndex = mouseDownIndex = -1;
    }
}

override void createWidget () {
    super.createWidget ();
    text = "";
    if (OS.COMCTL32_MAJOR < 6) {
        if ((style & DWT.MIRRORED) !is 0) {
            layout.setOrientation (DWT.RIGHT_TO_LEFT);
        }
        initAccessible ();
    }
}

void drawWidget (GC gc, RECT* rect) {
    drawBackground (gc.handle, rect);
    int selStart = selection.x;
    int selEnd = selection.y;
    if (selStart > selEnd) {
        selStart = selection.y;
        selEnd = selection.x;
    }
    // temporary code to disable text selection
    selStart = selEnd = -1;
    if (!OS.IsWindowEnabled (handle)) gc.setForeground (disabledColor);
    layout.draw (gc, 0, 0, selStart, selEnd, null, null);
    if (hasFocus () && focusIndex !is -1) {
        Rectangle [] rects = getRectangles (focusIndex);
        for (int i = 0; i < rects.length; i++) {
            Rectangle rectangle = rects [i];
            gc.drawFocus (rectangle.x, rectangle.y, rectangle.width, rectangle.height);
        }
    }
    if (hooks (DWT.Paint) || filters (DWT.Paint)) {
        Event event = new Event ();
        event.gc = gc;
        event.x = rect.left;
        event.y = rect.top;
        event.width = rect.right - rect.left;
        event.height = rect.bottom - rect.top;
        sendEvent (DWT.Paint, event);
        event.gc = null;
    }
}

override void enableWidget (bool enabled) {
    if (OS.COMCTL32_MAJOR >= 6) {
        LITEM item;
        item.mask = OS.LIF_ITEMINDEX | OS.LIF_STATE;
        item.stateMask = OS.LIS_ENABLED;
        item.state = enabled ? OS.LIS_ENABLED : 0;
        while (OS.SendMessage (handle, OS.LM_SETITEM, 0, &item) !is 0) {
            item.iLink++;
        }
    } else {
        TextStyle linkStyle = new TextStyle (null, enabled ? linkColor : disabledColor, null);
        linkStyle.underline = true;
        for (int i = 0; i < offsets.length; i++) {
            Point point = offsets [i];
            layout.setStyle (linkStyle, point.x, point.y);
        }
        redraw ();
    }
    /*
    * Feature in Windows.  For some reason, setting
    * LIS_ENABLED state using LM_SETITEM causes the
    * SysLink to become enabled.  To be specific,
    * calling IsWindowEnabled() returns true.  The
    * fix is disable the SysLink after LM_SETITEM.
    */
    super.enableWidget (enabled);
}

void initAccessible () {
    Accessible accessible = getAccessible ();
    accessible.addAccessibleListener (new class() AccessibleAdapter {
        public void getName (AccessibleEvent e) {
            e.result = parse (text);
        }
    });

    accessible.addAccessibleControlListener (new class() AccessibleControlAdapter {
        public void getChildAtPoint (AccessibleControlEvent e) {
            e.childID = ACC.CHILDID_SELF;
        }

        public void getLocation (AccessibleControlEvent e) {
            Rectangle rect = display.map (getParent (), null, getBounds ());
            e.x = rect.x;
            e.y = rect.y;
            e.width = rect.width;
            e.height = rect.height;
        }

        public void getChildCount (AccessibleControlEvent e) {
            e.detail = 0;
        }

        public void getRole (AccessibleControlEvent e) {
            e.detail = ACC.ROLE_LINK;
        }

        public void getState (AccessibleControlEvent e) {
            e.detail = ACC.STATE_FOCUSABLE;
            if (hasFocus ()) e.detail |= ACC.STATE_FOCUSED;
        }

        public void getDefaultAction (AccessibleControlEvent e) {
            e.result = DWT.getMessage ("SWT_Press"); //$NON-NLS-1$
        }

        public void getSelection (AccessibleControlEvent e) {
            if (hasFocus ()) e.childID = ACC.CHILDID_SELF;
        }

        public void getFocus (AccessibleControlEvent e) {
            if (hasFocus ()) e.childID = ACC.CHILDID_SELF;
        }
    });
}

override String getNameText () {
    return getText ();
}

Rectangle [] getRectangles (int linkIndex) {
    int lineCount = layout.getLineCount ();
    Rectangle [] rects = new Rectangle [lineCount];
    int [] lineOffsets = layout.getLineOffsets ();
    Point point = offsets [linkIndex];
    int lineStart = 1;
    while (point.x > lineOffsets [lineStart]) lineStart++;
    int lineEnd = 1;
    while (point.y > lineOffsets [lineEnd]) lineEnd++;
    int index = 0;
    if (lineStart is lineEnd) {
        rects [index++] = layout.getBounds (point.x, point.y);
    } else {
        rects [index++] = layout.getBounds (point.x, lineOffsets [lineStart]-1);
        rects [index++] = layout.getBounds (lineOffsets [lineEnd-1], point.y);
        if (lineEnd - lineStart > 1) {
            for (int i = lineStart; i < lineEnd - 1; i++) {
                rects [index++] = layout.getLineBounds (i);
            }
        }
    }
    if (rects.length !is index) {
        Rectangle [] tmp = new Rectangle [index];
        System.arraycopy (rects, 0, tmp, 0, index);
        rects = tmp;
    }
    return rects;
}

/**
 * Returns the receiver's text, which will be an empty
 * string if it has never been set.
 *
 * @return the receiver's text
 *
 * @exception DWTException <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;
}

String parse (String string) {
    int length_ = string.length;
    offsets = new Point [length_ / 4];
    ids = new String [length_ / 4];
    mnemonics = new int [length_ / 4 + 1];
    StringBuffer result = new StringBuffer ();
    char [] buffer = new char [length_];
    string.getChars (0, string.length, buffer, 0);
    int index = 0, state = 0, linkIndex = 0;
    int start = 0, tagStart = 0, linkStart = 0, endtagStart = 0, refStart = 0;

    while (index < length_) {

        // instead Character.toLower
        // only needed for the control symbols, which are always ascii
        char c = buffer[index];
        if( c >= 'A' && c <= 'Z' ){
            c -= ( 'A' - 'a' );
        }

        // only simple ascii whitespace needed
        bool isWhitespace(char w ){
            switch(w){
                case ' ': return true;
                default : return false;
            }
        }

        switch (state) {
            case 0:
                if (c is '<') {
                    tagStart = index;
                    state++;
                }
                break;
            case 1:
                if (c is 'a') state++;
                break;
            case 2:
                switch (c) {
                    case 'h':
                        state = 7;
                        break;
                    case '>':
                        linkStart = index  + 1;
                        state++;
                        break;
                    default:
                        if (isWhitespace(c)) break;
                        else state = 13;
                }
                break;
            case 3:
                if (c is '<') {
                    endtagStart = index;
                    state++;
                }
                break;
            case 4:
                state = c is '/' ? state + 1 : 3;
                break;
            case 5:
                state = c is 'a' ? state + 1 : 3;
                break;
            case 6:
                if (c is '>') {
                    mnemonics [linkIndex] = parseMnemonics (buffer, start, tagStart, result);
                    int offset = result.length;
                    parseMnemonics (buffer, linkStart, endtagStart, result);
                    offsets [linkIndex] = new Point (offset, result.length - 1);
                    if (ids [linkIndex] is null) {
                        ids [linkIndex] = buffer[ linkStart .. endtagStart ].dup;
                    }
                    linkIndex++;
                    start = tagStart = linkStart = endtagStart = refStart = index + 1;
                    state = 0;
                } else {
                    state = 3;
                }
                break;
            case 7:
                state = c is 'r' ? state + 1 : 0;
                break;
            case 8:
                state = c is 'e' ? state + 1 : 0;
                break;
            case 9:
                state = c is 'f' ? state + 1 : 0;
                break;
            case 10:
                state = c is '=' ? state + 1 : 0;
                break;
            case 11:
                if (c is '"') {
                    state++