org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewerHoverManager.java - platform/eclipse.platform.text - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2003 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.jface.text;


 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Display;


 /**
  * This manager controls the layout, content, and visibility of an information
  * control in reaction to mouse hover events issued by the text widget of a
  * text viewer. It overrides <code>computeInformation</code>, so that the
  * computation is performed in a dedicated background thread. This implies
  * that the used <code>ITextHover</code> objects must be capable of
  * operating in a non-UI thread.
  *
  * @since 2.0
  */
 class TextViewerHoverManager extends AbstractHoverInformationControlManager implements IWidgetTokenKeeper {

 	/** The text viewer */
 	private TextViewer fTextViewer;
 	/** The hover information computation thread */
 	private Thread fThread;
 	/** The stopper of the computation thread */
 	private ITextListener fStopper;
 	/** Internal monitor */
 	private Object fMutex= new Object();
 	/** The currently shown text hover. */
 	private volatile ITextHover fTextHover;

 	/**
 	 * Creates a new text viewer hover manager specific for the given text viewer.
 	 * The manager uses the given information control creator.
 	 *
 	 * @param textViewer the viewer for which the controller is created
 	 * @param creator the information control creator
 	 */
 	public TextViewerHoverManager(TextViewer textViewer, IInformationControlCreator creator) {
 		super(creator);
 		fTextViewer= textViewer;
 		fStopper= new ITextListener() {
 			public void textChanged(TextEvent event) {
 				synchronized (fMutex) {
 					if (fThread != null) {
 						fThread.interrupt();
 						fThread= null;
 					}
 				}
 			}
 		};
 	}

 	/**
 	 * Determines all necessary details and delegates the computation into
 	 * a background thread.
 	 */
 	protected void computeInformation() {

 		Point location= getHoverEventLocation();
 		int offset= computeOffsetAtLocation(location.x, location.y);
 		if (offset == -1) {
 			setInformation(null, null);
 			return;
 		}

 		final ITextHover hover= fTextViewer.getTextHover(offset, getHoverEventStateMask());
 		if (hover == null) {
 			setInformation(null, null);
 			return;
 		}

 		final IRegion region= hover.getHoverRegion(fTextViewer, offset);
 		if (region == null) {
 			setInformation(null, null);
 			return;
 		}

 		final Rectangle area= computeArea(region);
 		if (area == null || area.isEmpty()) {
 			setInformation(null, null);
 			return;
 		}

 		if (fThread != null) {
 			setInformation(null, null);
 			return;
 		}

 		fThread= new Thread("Text Viewer Hover Presenter") { //$NON-NLS-1$
 			public void run() {
 				// http://bugs.eclipse.org/bugs/show_bug.cgi?id=17693
 				try {

 					if (fThread != null) {
 						String information;
 						try {
 							information= hover.getHoverInfo(fTextViewer, region);
 						} catch (ArrayIndexOutOfBoundsException x) {
 							/*
 							 * This code runs in a separate thread which can
 							 * lead to text offsets being out of bounds when
 							 * computing the hover info (see bug 32848).
 							 */
 							information= null;
 						}
 						setInformation(information, area);
 						if (information != null && area != null)
 							fTextHover= hover;
 					} else {
 						setInformation(null, null);
 					}

 				} finally {
 					synchronized (fMutex) {
 						if (fTextViewer != null)
 							fTextViewer.removeTextListener(fStopper);
 						fThread= null;
 					}
 				}
 			}
 		};

 		fThread.setDaemon(true);
 		fThread.setPriority(Thread.MIN_PRIORITY);
 		synchronized (fMutex) {
 			fTextViewer.addTextListener(fStopper);
 			fThread.start();
 		}
 	}

 	/**
 	 * As computation is done in the background, this method is
 	 * also called in the background thread. Delegates the control
 	 * flow back into the ui thread, in order to allow displaying the
 	 * information in the information control.
 	 */
 	protected void presentInformation() {
 		if (fTextViewer == null)
 			return;

 		StyledText textWidget= fTextViewer.getTextWidget();
 		if (textWidget != null && !textWidget.isDisposed()) {
 			Display display= textWidget.getDisplay();
 			if (display == null)
 				return;

 			display.asyncExec(new Runnable() {
 				public void run() {
 					doPresentInformation();
 				}
 			});
 		}
 	}

 	/*
 	 * @see AbstractInformationControlManager#presentInformation()
 	 */
 	protected void doPresentInformation() {
 		super.presentInformation();
 	}

 	/**
 	 * Computes the document offset underlying the given text widget coordinates.
 	 * This method uses a linear search as it cannot make any assumption about
 	 * how the document is actually presented in the widget. (Covers cases such
 	 * as bidi text.)
 	 *
 	 * @param x the x coordinate inside the text widget
 	 * @param y the y coordinate inside the text widget
 	 * @return the document offset corresponding to the given point
 	 */
 	private int computeOffsetAtLocation(int x, int y) {

 		try {

 			StyledText styledText= fTextViewer.getTextWidget();
 			int widgetOffset= styledText.getOffsetAtLocation(new Point(x, y));

 			if (fTextViewer instanceof ITextViewerExtension3) {
 				ITextViewerExtension3 extension= (ITextViewerExtension3) fTextViewer;
 				return extension.widgetOffset2ModelOffset(widgetOffset);
 			}

 			return widgetOffset + fTextViewer._getVisibleRegionOffset();

 		} catch (IllegalArgumentException e) {
 			return -1;
 		}
 	}

 	/**
 	 * Determines graphical area covered by the given text region.
 	 *
 	 * @param region the region whose graphical extend must be computed
 	 * @return the graphical extend of the given region
 	 */
 	private Rectangle computeArea(IRegion region) {

 		IRegion widgetRegion= modelRange2WidgetRange(region);
 		int start= widgetRegion.getOffset();
 		int end= widgetRegion.getOffset() + widgetRegion.getLength();

 		StyledText styledText= fTextViewer.getTextWidget();
 		Point upperLeft= styledText.getLocationAtOffset(start);
 		Point lowerRight= new Point(upperLeft.x, upperLeft.y);

 		for (int i= start +1; i < end; i++) {

 			Point p= styledText.getLocationAtOffset(i);

 			if (upperLeft.x > p.x)
 				upperLeft.x= p.x;

 			if (upperLeft.y > p.y)
 				upperLeft.y= p.y;

 			if (lowerRight.x  < p.x)
 				lowerRight.x= p.x;

 			if (lowerRight.y < p.y)
 				lowerRight.y= p.y;
 		}

 		lowerRight.x += fTextViewer.getAverageCharWidth();
 		lowerRight.y += styledText.getLineHeight();

 		int width= lowerRight.x - upperLeft.x;
 		int height= lowerRight.y - upperLeft.y;
 		return new Rectangle(upperLeft.x, upperLeft.y, width, height);
 	}

 	/**
 	 * Translates a given region of the text viewer's document into
 	 * the corresponding region of the viewer's widget.
 	 *
 	 * @param region the document region
 	 * @return the corresponding widget region
 	 * @since 2.1
 	 */
 	private IRegion modelRange2WidgetRange(IRegion region) {
 		if (fTextViewer instanceof ITextViewerExtension3) {
 			ITextViewerExtension3 extension= (ITextViewerExtension3) fTextViewer;
 			return extension.modelRange2WidgetRange(region);
 		}

 		IRegion visibleRegion= fTextViewer.getVisibleRegion();
 		int start= region.getOffset() - visibleRegion.getOffset();
 		int end= start + region.getLength();
 		if (end > visibleRegion.getLength())
 			end= visibleRegion.getLength();

 		return new Region(start, end - start);
 	}

 	/*
 	 * @see AbstractInformationControlManager#showInformationControl(Rectangle)
 	 */
 	protected void showInformationControl(Rectangle subjectArea) {
 		if (fTextViewer != null && fTextViewer.requestWidgetToken(this))
 			super.showInformationControl(subjectArea);
 	}

 	/*
 	 * @see AbstractInformationControlManager#hideInformationControl()
 	 */
 	protected void hideInformationControl() {
 		try {
 			fTextHover= null;
 			super.hideInformationControl();
 		} finally {
 			if (fTextViewer != null)
 				fTextViewer.releaseWidgetToken(this);
 		}
 	}

 	/*
 	 * @see AbstractInformationControlManager#handleInformationControlDisposed()
 	 */
 	protected void handleInformationControlDisposed() {
 		try {
 			super.handleInformationControlDisposed();
 		} finally {
 			if (fTextViewer != null)
 				fTextViewer.releaseWidgetToken(this);
 		}
 	}

 	/*
 	 * @see IWidgetTokenKeeper#requestWidgetToken(IWidgetTokenOwner)
 	 */
 	public boolean requestWidgetToken(IWidgetTokenOwner owner) {
 		fTextHover= null;
 		super.hideInformationControl();
 		return true;
 	}

 	/**
 	 * Returns the currently shown text hover or <code>null</code> if no text
 	 * hover is shown.
 	 *
 	 * @return the currently shown text hover or <code>null</code>
 	 */
 	protected ITextHover getCurrentTextHover() {
 		return fTextHover;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2003 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Common Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/cpl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/

	package org.eclipse.jface.text;


	import org.eclipse.swt.custom.StyledText;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.widgets.Display;


	/**
	* This manager controls the layout, content, and visibility of an information
	* control in reaction to mouse hover events issued by the text widget of a
	* text viewer. It overrides <code>computeInformation</code>, so that the
	* computation is performed in a dedicated background thread. This implies
	* that the used <code>ITextHover</code> objects must be capable of
	* operating in a non-UI thread.
	*
	* @since 2.0
	*/
	class TextViewerHoverManager extends AbstractHoverInformationControlManager implements IWidgetTokenKeeper {

	/** The text viewer */
	private TextViewer fTextViewer;
	/** The hover information computation thread */
	private Thread fThread;
	/** The stopper of the computation thread */
	private ITextListener fStopper;
	/** Internal monitor */
	private Object fMutex= new Object();
	/** The currently shown text hover. */
	private volatile ITextHover fTextHover;

	/**
	* Creates a new text viewer hover manager specific for the given text viewer.
	* The manager uses the given information control creator.
	*
	* @param textViewer the viewer for which the controller is created
	* @param creator the information control creator
	*/
	public TextViewerHoverManager(TextViewer textViewer, IInformationControlCreator creator) {
	super(creator);
	fTextViewer= textViewer;
	fStopper= new ITextListener() {
	public void textChanged(TextEvent event) {
	synchronized (fMutex) {
	if (fThread != null) {
	fThread.interrupt();
	fThread= null;
	}
	}
	}
	};
	}

	/**
	* Determines all necessary details and delegates the computation into
	* a background thread.
	*/
	protected void computeInformation() {

	Point location= getHoverEventLocation();
	int offset= computeOffsetAtLocation(location.x, location.y);
	if (offset == -1) {
	setInformation(null, null);
	return;
	}

	final ITextHover hover= fTextViewer.getTextHover(offset, getHoverEventStateMask());
	if (hover == null) {
	setInformation(null, null);
	return;
	}

	final IRegion region= hover.getHoverRegion(fTextViewer, offset);
	if (region == null) {
	setInformation(null, null);
	return;
	}

	final Rectangle area= computeArea(region);
	if (area == null \|\| area.isEmpty()) {
	setInformation(null, null);
	return;
	}

	if (fThread != null) {
	setInformation(null, null);
	return;
	}

	fThread= new Thread("Text Viewer Hover Presenter") { //$NON-NLS-1$
	public void run() {
	// http://bugs.eclipse.org/bugs/show_bug.cgi?id=17693
	try {

	if (fThread != null) {
	String information;
	try {
	information= hover.getHoverInfo(fTextViewer, region);
	} catch (ArrayIndexOutOfBoundsException x) {
	/*
	* This code runs in a separate thread which can
	* lead to text offsets being out of bounds when
	* computing the hover info (see bug 32848).
	*/
	information= null;
	}
	setInformation(information, area);
	if (information != null && area != null)
	fTextHover= hover;
	} else {
	setInformation(null, null);
	}

	} finally {
	synchronized (fMutex) {
	if (fTextViewer != null)
	fTextViewer.removeTextListener(fStopper);
	fThread= null;
	}
	}
	}
	};

	fThread.setDaemon(true);
	fThread.setPriority(Thread.MIN_PRIORITY);
	synchronized (fMutex) {
	fTextViewer.addTextListener(fStopper);
	fThread.start();
	}
	}

	/**
	* As computation is done in the background, this method is
	* also called in the background thread. Delegates the control
	* flow back into the ui thread, in order to allow displaying the
	* information in the information control.
	*/
	protected void presentInformation() {
	if (fTextViewer == null)
	return;

	StyledText textWidget= fTextViewer.getTextWidget();
	if (textWidget != null && !textWidget.isDisposed()) {
	Display display= textWidget.getDisplay();
	if (display == null)
	return;

	display.asyncExec(new Runnable() {
	public void run() {
	doPresentInformation();
	}
	});
	}
	}

	/*
	* @see AbstractInformationControlManager#presentInformation()
	*/
	protected void doPresentInformation() {
	super.presentInformation();
	}

	/**
	* Computes the document offset underlying the given text widget coordinates.
	* This method uses a linear search as it cannot make any assumption about
	* how the document is actually presented in the widget. (Covers cases such
	* as bidi text.)
	*
	* @param x the x coordinate inside the text widget
	* @param y the y coordinate inside the text widget
	* @return the document offset corresponding to the given point
	*/
	private int computeOffsetAtLocation(int x, int y) {

	try {

	StyledText styledText= fTextViewer.getTextWidget();
	int widgetOffset= styledText.getOffsetAtLocation(new Point(x, y));

	if (fTextViewer instanceof ITextViewerExtension3) {
	ITextViewerExtension3 extension= (ITextViewerExtension3) fTextViewer;
	return extension.widgetOffset2ModelOffset(widgetOffset);
	}

	return widgetOffset + fTextViewer._getVisibleRegionOffset();

	} catch (IllegalArgumentException e) {
	return -1;
	}
	}

	/**
	* Determines graphical area covered by the given text region.
	*
	* @param region the region whose graphical extend must be computed
	* @return the graphical extend of the given region
	*/
	private Rectangle computeArea(IRegion region) {

	IRegion widgetRegion= modelRange2WidgetRange(region);
	int start= widgetRegion.getOffset();
	int end= widgetRegion.getOffset() + widgetRegion.getLength();

	StyledText styledText= fTextViewer.getTextWidget();
	Point upperLeft= styledText.getLocationAtOffset(start);
	Point lowerRight= new Point(upperLeft.x, upperLeft.y);

	for (int i= start +1; i < end; i++) {

	Point p= styledText.getLocationAtOffset(i);

	if (upperLeft.x > p.x)
	upperLeft.x= p.x;

	if (upperLeft.y > p.y)
	upperLeft.y= p.y;

	if (lowerRight.x < p.x)
	lowerRight.x= p.x;

	if (lowerRight.y < p.y)
	lowerRight.y= p.y;
	}

	lowerRight.x += fTextViewer.getAverageCharWidth();
	lowerRight.y += styledText.getLineHeight();

	int width= lowerRight.x - upperLeft.x;
	int height= lowerRight.y - upperLeft.y;
	return new Rectangle(upperLeft.x, upperLeft.y, width, height);
	}

	/**
	* Translates a given region of the text viewer's document into
	* the corresponding region of the viewer's widget.
	*
	* @param region the document region
	* @return the corresponding widget region
	* @since 2.1
	*/
	private IRegion modelRange2WidgetRange(IRegion region) {
	if (fTextViewer instanceof ITextViewerExtension3) {
	ITextViewerExtension3 extension= (ITextViewerExtension3) fTextViewer;
	return extension.modelRange2WidgetRange(region);
	}

	IRegion visibleRegion= fTextViewer.getVisibleRegion();
	int start= region.getOffset() - visibleRegion.getOffset();
	int end= start + region.getLength();
	if (end > visibleRegion.getLength())
	end= visibleRegion.getLength();

	return new Region(start, end - start);
	}

	/*
	* @see AbstractInformationControlManager#showInformationControl(Rectangle)
	*/
	protected void showInformationControl(Rectangle subjectArea) {
	if (fTextViewer != null && fTextViewer.requestWidgetToken(this))
	super.showInformationControl(subjectArea);
	}

	/*
	* @see AbstractInformationControlManager#hideInformationControl()
	*/
	protected void hideInformationControl() {
	try {
	fTextHover= null;
	super.hideInformationControl();
	} finally {
	if (fTextViewer != null)
	fTextViewer.releaseWidgetToken(this);
	}
	}

	/*
	* @see AbstractInformationControlManager#handleInformationControlDisposed()
	*/
	protected void handleInformationControlDisposed() {
	try {
	super.handleInformationControlDisposed();
	} finally {
	if (fTextViewer != null)
	fTextViewer.releaseWidgetToken(this);
	}
	}

	/*
	* @see IWidgetTokenKeeper#requestWidgetToken(IWidgetTokenOwner)
	*/
	public boolean requestWidgetToken(IWidgetTokenOwner owner) {
	fTextHover= null;
	super.hideInformationControl();
	return true;
	}

	/**
	* Returns the currently shown text hover or <code>null</code> if no text
	* hover is shown.
	*
	* @return the currently shown text hover or <code>null</code>
	*/
	protected ITextHover getCurrentTextHover() {
	return fTextHover;
	}
	}