1 files changed, 300 insertions, 0 deletions
diff --git a/org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewerHoverManager.java b/org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewerHoverManager.java
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index 00000000000..426bdb67db8
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+++ b/org.eclipse.jface.text/src/org/eclipse/jface/text/TextViewerHoverManager.java
@@ -0,0 +1,300 @@
+/**********************************************************************
+Copyright (c) 2000, 2002 IBM Corp. 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 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();
+	
+	
+	/**
+	 * 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);
+		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() {
+			public void run() {
+				// http://bugs.eclipse.org/bugs/show_bug.cgi?id=17693			
+				try {
+					
+					if (fThread != null) {
+						String information= hover.getHoverInfo(fTextViewer, region);
+						setInformation(information, area);
+					} 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) {
+		
+		StyledText styledText= fTextViewer.getTextWidget();
+		IDocument document= fTextViewer.getVisibleDocument();
+		
+		if (document == null)
+			return -1;		
+		
+		int line= (y + styledText.getTopPixel()) / styledText.getLineHeight();
+		int lineCount= document.getNumberOfLines();
+		
+		if (line > lineCount - 1)
+			line= lineCount - 1;
+		
+		if (line < 0)
+			line= 0;
+		
+		try {
+			
+			IRegion lineInfo= document.getLineInformation(line);
+			int low= lineInfo.getOffset();
+			int high= low + lineInfo.getLength();
+			
+			int lookup= styledText.getLocationAtOffset(low).x;
+			int guess= low;
+			int guessDelta= Math.abs(lookup - x);
+			
+			for (int i= low + 1; i < high; i++) {
+				lookup= styledText.getLocationAtOffset(i).x;
+				int delta= Math.abs(lookup - x);
+				if (delta < guessDelta) {
+					guess= i;
+					guessDelta= delta;
+				}
+			}
+			
+			return guess + fTextViewer.getVisibleRegionOffset();
+		
+		} catch (BadLocationException 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) {
+				
+		StyledText styledText= fTextViewer.getTextWidget();
+		
+		IRegion visibleRegion= fTextViewer.getVisibleRegion();
+		int start= region.getOffset() - visibleRegion.getOffset();
+		int end= start + region.getLength();
+		if (end > visibleRegion.getLength())
+			end= visibleRegion.getLength();
+		
+		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);
+	}
+	
+	/*
+	 * @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 {
+			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) {
+		super.hideInformationControl();
+		return true;
+	}
+}
+