--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwt/dnd/TreeDropTargetEffect.d	Sat Aug 09 17:00:02 2008 +0200
@@ -0,0 +1,265 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2007 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
+ *******************************************************************************/
+module dwt.dnd;
+
+import dwt.*;
+import dwt.graphics.*;
+import dwt.internal.Callback;
+import dwt.internal.carbon.DataBrowserCallbacks;
+import dwt.internal.carbon.OS;
+import dwt.widgets.*;
+
+/**
+ * This class provides a default drag under effect (eg. select, insert, scroll and expand) 
+ * when a drag occurs over a <code>Tree</code>.
+ * 
+ * <p>Classes that wish to provide their own drag under effect for a <code>Tree</code>
+ * can extend the <code>TreeDropTargetEffect</code> class and override any applicable methods 
+ * in <code>TreeDropTargetEffect</code> to display their own drag under effect.</p>
+ *
+ * Subclasses that override any methods of this class must call the corresponding
+ * <code>super</code> method to get the default drag under effect implementation.
+ *
+ * <p>The feedback value is either one of the FEEDBACK constants defined in 
+ * class <code>DND</code> which is applicable to instances of this class, 
+ * or it must be built by <em>bitwise OR</em>'ing together 
+ * (that is, using the <code>int</code> "|" operator) two or more
+ * of those <code>DND</code> effect constants. 
+ * </p>
+ * <p>
+ * <dl>
+ * <dt><b>Feedback:</b></dt>
+ * <dd>FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE, FEEDBACK_INSERT_AFTER, FEEDBACK_EXPAND, FEEDBACK_SCROLL</dd>
+ * </dl>
+ * </p><p>
+ * Note: Only one of the styles FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE or
+ * FEEDBACK_INSERT_AFTER may be specified.
+ * </p>
+ * 
+ * @see DropTargetAdapter
+ * @see DropTargetEvent
+ * 
+ * @since 3.3
+ */
+public class TreeDropTargetEffect : DropTargetEffect {
+    static final int SCROLL_HYSTERESIS = 150; // milli seconds
+    static final int EXPAND_HYSTERESIS = 1000; // milli seconds
+
+    int currentEffect = DND.FEEDBACK_NONE;
+    TreeItem currentItem;
+
+    TreeItem insertItem = null;
+    bool insertBefore = false;
+
+    TreeItem scrollItem;
+    long scrollBeginTime;
+
+    TreeItem expandItem;
+    long expandBeginTime;
+    
+    DataBrowserCallbacks callbacks = null;
+    
+    int acceptDragProc(int theControl, int itemID, int property, int theRect, int theDrag) {
+        return (currentEffect & DND.FEEDBACK_SELECT) !is 0 ? 1 : 0;
+    }
+
+    static Callback AcceptDragProc;
+    static {
+        AcceptDragProc = new Callback(TreeDropTargetEffect.class, "AcceptDragProc", 5); //$NON-NLS-1$
+        int acceptDragProc = AcceptDragProc.getAddress();
+        if (acceptDragProc is 0) DWT.error(DWT.ERROR_NO_MORE_CALLBACKS);
+    }
+
+    static int AcceptDragProc(int theControl, int itemID, int property, int theRect, int theDrag) {
+        DropTarget target = FindDropTarget(theControl, theDrag);
+        if (target is null) return 0;
+        return (target.feedback & DND.FEEDBACK_SELECT) !is 0 ? 1 : 0;
+    }
+    
+    static DropTarget FindDropTarget(int theControl, int theDrag) {
+        if (theControl is 0) return null;
+        Display display = Display.findDisplay(Thread.currentThread());
+        if (display is null || display.isDisposed()) return null;
+        Widget widget = display.findWidget(theControl);
+        if (widget is null) return null;
+        return (DropTarget)widget.getData(DND.DROP_TARGET_KEY); 
+    }
+
+    /**
+     * Creates a new <code>TreeDropTargetEffect</code> to handle the drag under effect on the specified 
+     * <code>Tree</code>.
+     * 
+     * @param tree the <code>Tree</code> over which the user positions the cursor to drop the data
+     */
+    public TreeDropTargetEffect(Tree tree) {
+        super(tree);
+    }
+
+    int checkEffect(int effect) {
+        // Some effects are mutually exclusive.  Make sure that only one of the mutually exclusive effects has been specified.
+        if ((effect & DND.FEEDBACK_SELECT) !is 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE;
+        if ((effect & DND.FEEDBACK_INSERT_BEFORE) !is 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER;
+        return effect;
+    }
+
+    /**
+     * This implementation of <code>dragEnter</code> provides a default drag under effect
+     * for the feedback specified in <code>event.feedback</code>.
+     * 
+     * For additional information see <code>DropTargetAdapter.dragEnter</code>.
+     * 
+     * Subclasses that override this method should call <code>super.dragEnter(event)</code>
+     * to get the default drag under effect implementation.
+     *
+     * @param event  the information associated with the drag enter event
+     * 
+     * @see DropTargetAdapter
+     * @see DropTargetEvent
+     */
+    public void dragEnter(DropTargetEvent event) {
+        if (callbacks is null) {
+            Tree table = (Tree) control;
+            DataBrowserCallbacks callbacks = new DataBrowserCallbacks ();
+            OS.GetDataBrowserCallbacks (table.handle, callbacks);
+            callbacks.v1_acceptDragCallback = AcceptDragProc.getAddress();
+            OS.SetDataBrowserCallbacks(table.handle, callbacks);
+        }
+        insertItem = null;
+        expandBeginTime = 0;
+        expandItem = null;
+        scrollBeginTime = 0;
+        scrollItem = null;
+    }
+
+    /**
+     * This implementation of <code>dragLeave</code> provides a default drag under effect
+     * for the feedback specified in <code>event.feedback</code>.
+     * 
+     * For additional information see <code>DropTargetAdapter.dragLeave</code>.
+     * 
+     * Subclasses that override this method should call <code>super.dragLeave(event)</code>
+     * to get the default drag under effect implementation.
+     *
+     * @param event  the information associated with the drag leave event
+     * 
+     * @see DropTargetAdapter
+     * @see DropTargetEvent
+     */
+    public void dragLeave(DropTargetEvent event) {
+        Tree tree = (Tree) control;
+        if (insertItem !is null) {
+            setInsertMark(tree, null, false);
+            insertItem = null;
+        }
+        expandBeginTime = 0;
+        expandItem = null;
+        scrollBeginTime = 0;
+        scrollItem = null;
+    }
+
+    /**
+     * This implementation of <code>dragOver</code> provides a default drag under effect
+     * for the feedback specified in <code>event.feedback</code>.
+     * 
+     * For additional information see <code>DropTargetAdapter.dragOver</code>.
+     * 
+     * Subclasses that override this method should call <code>super.dragOver(event)</code>
+     * to get the default drag under effect implementation.
+     *
+     * @param event  the information associated with the drag over event
+     * 
+     * @see DropTargetAdapter
+     * @see DropTargetEvent
+     * @see DND#FEEDBACK_SELECT
+     * @see DND#FEEDBACK_INSERT_BEFORE
+     * @see DND#FEEDBACK_INSERT_AFTER
+     * @see DND#FEEDBACK_SCROLL
+     */
+    public void dragOver(DropTargetEvent event) {
+        Tree tree = (Tree) control;
+        TreeItem item = (TreeItem)getItem(tree, event.x, event.y);
+        int effect = checkEffect(event.feedback);       
+        if ((effect & DND.FEEDBACK_EXPAND) is 0) {
+            expandBeginTime = 0;
+            expandItem = null;
+        } else {
+            if (item !is null && item.opEquals(expandItem) && expandBeginTime !is 0) {
+                if (System.currentTimeMillis() >= expandBeginTime) {
+                    if (item.getItemCount() > 0 && !item.getExpanded()) {
+                        Event e = new Event();
+                        e.x = event.x;
+                        e.y = event.y;
+                        e.item = item;
+                        e.time = (int) System.currentTimeMillis();
+                        tree.notifyListeners(DWT.Expand, e);
+                        if (item.isDisposed()) return;
+                        item.setExpanded(true);
+                    }
+                    expandBeginTime = 0;
+                    expandItem = null;
+                }
+            } else {
+                expandBeginTime = System.currentTimeMillis() + EXPAND_HYSTERESIS;
+                expandItem = item;
+            }
+        }
+        
+        if ((effect & DND.FEEDBACK_SCROLL) is 0) {
+            scrollBeginTime = 0;
+            scrollItem = null;
+        } else {
+            if (item !is null && item.opEquals(scrollItem)  && scrollBeginTime !is 0) {
+                if (System.currentTimeMillis() >= scrollBeginTime) {
+                    Rectangle area = tree.getClientArea();
+                    int headerHeight = tree.getHeaderHeight();
+                    int itemHeight= tree.getItemHeight();
+                    Point pt = new Point(event.x, event.y);
+                    pt = tree.getDisplay().map(null, tree, pt);
+                    TreeItem nextItem = null;
+                    if (pt.y < area.y + headerHeight + 2 * itemHeight) {
+                        nextItem = previousItem(tree, item);
+                    }
+                    if (pt.y > area.y + area.height - 2 * itemHeight) {
+                        nextItem = nextItem(tree, item);
+                    }
+                    if (nextItem !is null) tree.showItem(nextItem);
+                    scrollBeginTime = 0;
+                    scrollItem = null;
+                }
+            } else {
+                scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
+                scrollItem = item;
+            }
+        }
+        
+        if ((effect & DND.FEEDBACK_INSERT_AFTER) !is 0 ||
+            (effect & DND.FEEDBACK_INSERT_BEFORE) !is 0) {
+            if (currentItem !is item || 
+                 ((effect & DND.FEEDBACK_INSERT_AFTER) !is (currentEffect & DND.FEEDBACK_INSERT_AFTER)) ||
+                 ((effect & DND.FEEDBACK_INSERT_BEFORE) !is (currentEffect & DND.FEEDBACK_INSERT_BEFORE))) { 
+                setInsertMark(tree, item, (effect & DND.FEEDBACK_INSERT_BEFORE) !is 0);
+                currentEffect = effect;
+                currentItem = item;
+            }
+        } else {
+            setInsertMark(tree, null, false);
+        }
+        // save current effect for selection feedback
+        ((DropTarget)event.widget).feedback = effect;
+    }
+
+    void setInsertMark(Tree tree, TreeItem item, bool before) {
+        if (item is insertItem && before is insertBefore) return;
+        insertItem = item;
+        insertBefore = before;
+        tree.setInsertMark(item, before);
+    }
+}