/*******************************************************************************
* Copyright (c) 2000, 2011 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
*******************************************************************************/
package org.eclipse.swt.dnd;
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.internal.Callback;
import org.eclipse.swt.internal.carbon.CGPoint;
import org.eclipse.swt.internal.carbon.EventRecord;
import org.eclipse.swt.internal.carbon.OS;
import org.eclipse.swt.internal.carbon.Point;
/**
*
* <code>DragSource</code> defines the source object for a drag and drop transfer.
*
* <p>IMPORTANT: This class is <em>not</em> intended to be subclassed.</p>
*
* <p>A drag source is the object which originates a drag and drop operation. For the specified widget,
* it defines the type of data that is available for dragging and the set of operations that can
* be performed on that data. The operations can be any bit-wise combination of DND.MOVE, DND.COPY or
* DND.LINK. The type of data that can be transferred is specified by subclasses of Transfer such as
* TextTransfer or FileTransfer. The type of data transferred can be a predefined system type or it
* can be a type defined by the application. For instructions on how to define your own transfer type,
* refer to <code>ByteArrayTransfer</code>.</p>
*
* <p>You may have several DragSources in an application but you can only have one DragSource
* per Control. Data dragged from this DragSource can be dropped on a site within this application
* or it can be dropped on another application such as an external Text editor.</p>
*
* <p>The application supplies the content of the data being transferred by implementing the
* <code>DragSourceListener</code> and associating it with the DragSource via DragSource#addDragListener.</p>
*
* <p>When a successful move operation occurs, the application is required to take the appropriate
* action to remove the data from its display and remove any associated operating system resources or
* internal references. Typically in a move operation, the drop target makes a copy of the data
* and the drag source deletes the original. However, sometimes copying the data can take a long
* time (such as copying a large file). Therefore, on some platforms, the drop target may actually
* move the data in the operating system rather than make a copy. This is usually only done in
* file transfers. In this case, the drag source is informed in the DragEnd event that a
* DROP_TARGET_MOVE was performed. It is the responsibility of the drag source at this point to clean
* up its displayed information. No action needs to be taken on the operating system resources.</p>
*
* <p> The following example shows a Label widget that allows text to be dragged from it.</p>
*
* <code><pre>
* // Enable a label as a Drag Source
* Label label = new Label(shell, SWT.NONE);
* // This example will allow text to be dragged
* Transfer[] types = new Transfer[] {TextTransfer.getInstance()};
* // This example will allow the text to be copied or moved to the drop target
* int operations = DND.DROP_MOVE | DND.DROP_COPY;
*
* DragSource source = new DragSource(label, operations);
* source.setTransfer(types);
* source.addDragListener(new DragSourceListener() {
* public void dragStart(DragSourceEvent e) {
* // Only start the drag if there is actually text in the
* // label - this text will be what is dropped on the target.
* if (label.getText().length() == 0) {
* event.doit = false;
* }
* };
* public void dragSetData(DragSourceEvent event) {
* // A drop has been performed, so provide the data of the
* // requested type.
* // (Checking the type of the requested data is only
* // necessary if the drag source supports more than
* // one data type but is shown here as an example).
* if (TextTransfer.getInstance().isSupportedType(event.dataType)){
* event.data = label.getText();
* }
* }
* public void dragFinished(DragSourceEvent event) {
* // A Move operation has been performed so remove the data
* // from the source
* if (event.detail == DND.DROP_MOVE)
* label.setText("");
* }
* });
* </pre></code>
*
*
* <dl>
* <dt><b>Styles</b></dt> <dd>DND.DROP_NONE, DND.DROP_COPY, DND.DROP_MOVE, DND.DROP_LINK</dd>
* <dt><b>Events</b></dt> <dd>DND.DragStart, DND.DragSetData, DND.DragEnd</dd>
* </dl>
*
* @see <a href="http://www.eclipse.org/swt/snippets/#dnd">Drag and Drop snippets</a>
* @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: DNDExample</a>
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
* @noextend This class is not intended to be subclassed by clients.
*/
public class DragSource extends Widget {
// info for registering as a drag source
Control control;
Listener controlListener;
Transfer[] transferAgents = new Transfer[0];
DragSourceEffect dragEffect;
static final String DEFAULT_DRAG_SOURCE_EFFECT = "DEFAULT_DRAG_SOURCE_EFFECT"; //$NON-NLS-1$
static final String DRAG_STARTED = "org.eclipse.swt.internal.dragStarted"; //$NON-NLS-1$
static Callback DragSendDataProc;
static {
DragSendDataProc = new Callback(DragSource.class, "DragSendDataProc", 4); //$NON-NLS-1$
int dragSendDataProcAddress = DragSendDataProc.getAddress();
if (dragSendDataProcAddress == 0) SWT.error(SWT.ERROR_NO_MORE_CALLBACKS);
}
/**
* Creates a new <code>DragSource</code> to handle dragging from the specified <code>Control</code>.
* Creating an instance of a DragSource may cause system resources to be allocated depending on the platform.
* It is therefore mandatory that the DragSource instance be disposed when no longer required.
*
* @param control the <code>Control</code> that the user clicks on to initiate the drag
* @param style the bitwise OR'ing of allowed operations; this may be a combination of any of
* DND.DROP_NONE, DND.DROP_COPY, DND.DROP_MOVE, DND.DROP_LINK
*
* @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>
* @exception SWTError <ul>
* <li>ERROR_CANNOT_INIT_DRAG - unable to initiate drag source; this will occur if more than one
* drag source is created for a control or if the operating system will not allow the creation
* of the drag source</li>
* </ul>
*
* <p>NOTE: ERROR_CANNOT_INIT_DRAG should be an SWTException, since it is a
* recoverable error, but can not be changed due to backward compatibility.</p>
*
* @see Widget#dispose
* @see DragSource#checkSubclass
* @see DND#DROP_NONE
* @see DND#DROP_COPY
* @see DND#DROP_MOVE
* @see DND#DROP_LINK
*/
public DragSource(Control control, int style) {
super (control, checkStyle(style));
this.control = control;
if (control.getData(DND.DRAG_SOURCE_KEY) != null) {
DND.error(DND.ERROR_CANNOT_INIT_DRAG);
}
control.setData(DND.DRAG_SOURCE_KEY, this);
controlListener = new Listener () {
public void handleEvent (Event event) {
if (event.type == SWT.Dispose) {
if (!DragSource.this.isDisposed()) {
DragSource.this.dispose();
}
}
if (event.type == SWT.DragDetect) {
if (!DragSource.this.isDisposed()) {
DragSource.this.drag(event);
}
}
}
};
control.addListener (SWT.Dispose, controlListener);
control.addListener (SWT.DragDetect, controlListener);
this.addListener(SWT.Dispose, new Listener() {
public void handleEvent(Event e) {
onDispose();
}
});
Object effect = control.getData(DEFAULT_DRAG_SOURCE_EFFECT);
if (effect instanceof DragSourceEffect) {
dragEffect = (DragSourceEffect) effect;
} else if (control instanceof Tree) {
dragEffect = new TreeDragSourceEffect((Tree) control);
} else if (control instanceof Table) {
dragEffect = new TableDragSourceEffect((Table) control);
}
}
static int checkStyle (int style) {
if (style == SWT.NONE) return DND.DROP_MOVE;
return style;
}
static int DragSendDataProc(int theType, int dragSendRefCon, int theItemRef, int theDrag) {
DragSource source = FindDragSource(dragSendRefCon, theDrag);
if (source == null) return OS.cantGetFlavorErr;
return source.dragSendDataProc(theType, dragSendRefCon, theItemRef, theDrag);
}
static DragSource FindDragSource(int dragSendRefCon, int theDrag) {
if (dragSendRefCon == 0) return null;
Display display = Display.findDisplay(Thread.currentThread());
if (display == null || display.isDisposed()) return null;
Widget widget = display.findWidget(dragSendRefCon);
if (widget == null) return null;
return (DragSource)widget.getData(DND.DRAG_SOURCE_KEY);
}
/**
* Adds the listener to the collection of listeners who will
* be notified when a drag and drop operation is in progress, by sending
* it one of the messages defined in the <code>DragSourceListener</code>
* interface.
*
* <p><ul>
* <li><code>dragStart</code> is called when the user has begun the actions required to drag the widget.
* This event gives the application the chance to decide if a drag should be started.
* <li><code>dragSetData</code> is called when the data is required from the drag source.
* <li><code>dragFinished</code> is called when the drop has successfully completed (mouse up
* over a valid target) or has been terminated (such as hitting the ESC key). Perform cleanup
* such as removing data from the source side on a successful move operation.
* </ul></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 DragSourceListener
* @see #getDragListeners
* @see #removeDragListener
* @see DragSourceEvent
*/
public void addDragListener(DragSourceListener listener) {
if (listener == null) DND.error (SWT.ERROR_NULL_ARGUMENT);
DNDListener typedListener = new DNDListener (listener);
typedListener.dndWidget = this;
addListener (DND.DragStart, typedListener);
addListener (DND.DragSetData, typedListener);
addListener (DND.DragEnd, typedListener);
}
protected void checkSubclass () {
String name = getClass().getName ();
String validName = DragSource.class.getName();
if (!validName.equals(name)) {
DND.error (SWT.ERROR_INVALID_SUBCLASS);
}
}
void drag(Event dragEvent) {
DNDEvent event = new DNDEvent();
event.widget = this;
event.x = dragEvent.x;
event.y = dragEvent.y;
event.time = dragEvent.time;
event.doit = true;
notifyListeners(DND.DragStart, event);
if (!event.doit || transferAgents == null || transferAgents.length == 0) return;
int[] theDrag = new int[1];
if (OS.NewDrag(theDrag) != OS.noErr) {
event = new DNDEvent();
event.widget = this;
event.time = (int)System.currentTimeMillis();
event.doit = false;
event.detail = DND.DROP_NONE;
notifyListeners(DND.DragEnd, event);
return;
}
Point pt = new Point();
OS.GetGlobalMouse (pt);
for (int i = 0; i < transferAgents.length; i++) {
Transfer transfer = transferAgents[i];
if (transfer != null) {
int[] types = transfer.getTypeIds();
for (int j = 0; j < types.length; j++) {
OS.AddDragItemFlavor(theDrag[0], 1, types[j], null, 0, 0);
}
}
}
OS.SetDragSendProc(theDrag[0], DragSendDataProc.getAddress(), control.handle);
int theRegion = 0;
Image newImage = null;
try {
theRegion = OS.NewRgn();
OS.SetRectRgn(theRegion, (short)(pt.h), (short)(pt.v), (short)(pt.h+20), (short)(pt.v+20));
int operations = opToOsOp(getStyle());
//set operations twice - local and not local
OS.SetDragAllowableActions(theDrag[0], operations, true);
OS.SetDragAllowableActions(theDrag[0], operations, false);
Image image = event.image;
if (image != null) {
CGPoint imageOffsetPt = new CGPoint();
imageOffsetPt.x = 0;
imageOffsetPt.y = 0;
/*
* Bug in the Macintosh. For some reason, it seems that SetDragImageWithCGImage()
* expects an image with the alpha, otherwise the image does not draw. The fix is
* to make sure that the image has an alpha by creating a new image with alpha
* when necessary.
*/
if (OS.CGImageGetAlphaInfo(image.handle) == OS.kCGImageAlphaNoneSkipFirst) {
ImageData data = image.getImageData();
data.alpha = 0xFF;
newImage = new Image(image.getDevice(), data);
image = newImage;
}
OS.SetDragImageWithCGImage(theDrag[0], image.handle, imageOffsetPt, 0);
}
EventRecord theEvent = new EventRecord();
theEvent.message = OS.kEventMouseMoved;
theEvent.modifiers = (short)OS.GetCurrentEventKeyModifiers();
theEvent.what = (short)OS.osEvt;
theEvent.where_h = pt.h;
theEvent.where_v = pt.v;
control.setData(DRAG_STARTED, new Object());
int result = OS.TrackDrag(theDrag[0], theEvent, theRegion);
control.setData(DRAG_STARTED, null);
int operation = DND.DROP_NONE;
if (result == OS.noErr) {
int[] outAction = new int[1];
OS.GetDragDropAction(theDrag[0], outAction);
operation = osOpToOp(outAction[0]);
}
event = new DNDEvent();
event.widget = this;
event.time = (int)System.currentTimeMillis();
event.doit = result == OS.noErr;
event.detail = operation;
notifyListeners(DND.DragEnd, event);
} finally {
if (theRegion != 0) OS.DisposeRgn(theRegion);
if (newImage != null) newImage.dispose();
}
OS.DisposeDrag(theDrag[0]);
}
int dragSendDataProc(int theType, int dragSendRefCon, int theItemRef, int theDrag) {
control.setData(DRAG_STARTED, null);
if (theType == 0) return OS.badDragFlavorErr;
TransferData transferData = new TransferData();
transferData.type = theType;
DNDEvent event = new DNDEvent();
event.widget = this;
event.time = (int)System.currentTimeMillis();
event.dataType = transferData;
notifyListeners(DND.DragSetData, event);
if (!event.doit) return OS.dragNotAcceptedErr;
Transfer transfer = null;
for (int i = 0; i < transferAgents.length; i++) {
Transfer transferAgent = transferAgents[i];
if (transferAgent != null && transferAgent.isSupportedType(transferData)) {
transfer = transferAgent;
break;
}
}
if (transfer == null) return OS.badDragFlavorErr;
transfer.javaToNative(event.data, transferData);
if (transferData.result != OS.noErr) return transferData.result;
byte[] datum = transferData.data[0];
if (datum == null) return OS.cantGetFlavorErr;
int rc = OS.SetDragItemFlavorData(theDrag, theItemRef, theType, datum, datum.length, 0);
if (rc == OS.noErr && transfer instanceof FileTransfer) {
for (int i = 1; i < transferData.data.length; i++) {
datum = transferData.data[i];
if (datum == null) return OS.cantGetFlavorErr;
rc = OS.AddDragItemFlavor(theDrag, 1 + i, theType, datum, datum.length, 0);
if (rc != OS.noErr) break;
}
}
return rc;
}
/**
* Returns the Control which is registered for this DragSource. This is the control that the
* user clicks in to initiate dragging.
*
* @return the Control which is registered for this DragSource
*/
public Control getControl () {
return control;
}
/**
* Returns an array of listeners who will be notified when a drag and drop
* operation is in progress, by sending it one of the messages defined in
* the <code>DragSourceListener</code> interface.
*
* @return the listeners who will be notified when a drag and drop
* operation is in progress
*
* @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 DragSourceListener
* @see #addDragListener
* @see #removeDragListener
* @see DragSourceEvent
*
* @since 3.4
*/
public DragSourceListener[] getDragListeners() {
Listener[] listeners = getListeners(DND.DragStart);
int length = listeners.length;
DragSourceListener[] dragListeners = new DragSourceListener[length];
int count = 0;
for (int i = 0; i < length; i++) {
Listener listener = listeners[i];
if (listener instanceof DNDListener) {
dragListeners[count] = (DragSourceListener) ((DNDListener) listener).getEventListener();
count++;
}
}
if (count == length) return dragListeners;
DragSourceListener[] result = new DragSourceListener[count];
System.arraycopy(dragListeners, 0, result, 0, count);
return result;
}
/**
* Returns the drag effect that is registered for this DragSource. This drag
* effect will be used during a drag and drop operation.
*
* @return the drag effect that is registered for this DragSource
*
* @since 3.3
*/
public DragSourceEffect getDragSourceEffect() {
return dragEffect;
}
/**
* Returns the list of data types that can be transferred by this DragSource.
*
* @return the list of data types that can be transferred by this DragSource
*/
public Transfer[] getTransfer(){
return transferAgents;
}
void onDispose() {
if (control == null)
return;
if (controlListener != null) {
control.removeListener(SWT.Dispose, controlListener);
control.removeListener(SWT.DragDetect, controlListener);
}
controlListener = null;
control.setData(DND.DRAG_SOURCE_KEY, null);
control = null;
transferAgents = null;
}
int opToOsOp(int operation) {
int osOperation = 0;
if ((operation & DND.DROP_COPY) != 0){
osOperation |= OS.kDragActionCopy;
}
if ((operation & DND.DROP_LINK) != 0) {
osOperation |= OS.kDragActionAlias;
}
if ((operation & DND.DROP_MOVE) != 0) {
osOperation |= OS.kDragActionMove;
}
if ((operation & DND.DROP_TARGET_MOVE) != 0) {
osOperation |= OS.kDragActionDelete;
}
return osOperation;
}
int osOpToOp(int osOperation){
int operation = 0;
if ((osOperation & OS.kDragActionCopy) != 0){
operation |= DND.DROP_COPY;
}
if ((osOperation & OS.kDragActionAlias) != 0) {
operation |= DND.DROP_LINK;
}
if ((osOperation & OS.kDragActionDelete) != 0) {
operation |= DND.DROP_TARGET_MOVE;
}
if ((osOperation & OS.kDragActionMove) != 0) {
operation |= DND.DROP_MOVE;
}
if (osOperation == OS.kDragActionAll) {
operation = DND.DROP_COPY | DND.DROP_MOVE | DND.DROP_LINK;
}
return operation;
}
/**
* Removes the listener from the collection of listeners who will
* be notified when a drag and drop operation is in progress.
*
* @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 DragSourceListener
* @see #addDragListener
* @see #getDragListeners
*/
public void removeDragListener(DragSourceListener listener) {
if (listener == null) DND.error (SWT.ERROR_NULL_ARGUMENT);
removeListener (DND.DragStart, listener);
removeListener (DND.DragSetData, listener);
removeListener (DND.DragEnd, listener);
}
/**
* Specifies the drag effect for this DragSource. This drag effect will be
* used during a drag and drop operation.
*
* @param effect the drag effect that is registered for this DragSource
*
* @since 3.3
*/
public void setDragSourceEffect(DragSourceEffect effect) {
dragEffect = effect;
}
/**
* Specifies the list of data types that can be transferred by this DragSource.
* The application must be able to provide data to match each of these types when
* a successful drop has occurred.
*
* @param transferAgents a list of Transfer objects which define the types of data that can be
* dragged from this source
*/
public void setTransfer(Transfer[] transferAgents){
this.transferAgents = transferAgents;
}
}