/org.golang.godev/src/org/golang/godev/editors/NonRuleBasedDamagerRepairer.java

  1package org.golang.godev.editors;
  2
  3import org.eclipse.jface.text.BadLocationException;
  4import org.eclipse.jface.text.DocumentEvent;
  5import org.eclipse.jface.text.IDocument;
  6import org.eclipse.jface.text.IRegion;
  7import org.eclipse.jface.text.ITypedRegion;
  8import org.eclipse.jface.text.Region;
  9import org.eclipse.jface.text.TextAttribute;
 10import org.eclipse.jface.text.TextPresentation;
 11import org.eclipse.jface.text.presentation.IPresentationDamager;
 12import org.eclipse.jface.text.presentation.IPresentationRepairer;
 13import org.eclipse.core.runtime.Assert;
 14import org.eclipse.swt.custom.StyleRange;
 15
 16public class NonRuleBasedDamagerRepairer
 17	implements IPresentationDamager, IPresentationRepairer {
 18
 19	/** The document this object works on */
 20	protected IDocument fDocument;
 21	/** The default text attribute if non is returned as data by the current token */
 22	protected TextAttribute fDefaultTextAttribute;
 23	
 24	/**
 25	 * Constructor for NonRuleBasedDamagerRepairer.
 26	 */
 27	public NonRuleBasedDamagerRepairer(TextAttribute defaultTextAttribute) {
 28		Assert.isNotNull(defaultTextAttribute);
 29
 30		fDefaultTextAttribute = defaultTextAttribute;
 31	}
 32
 33	/**
 34	 * @see IPresentationRepairer#setDocument(IDocument)
 35	 */
 36	public void setDocument(IDocument document) {
 37		fDocument = document;
 38	}
 39
 40	/**
 41	 * Returns the end offset of the line that contains the specified offset or
 42	 * if the offset is inside a line delimiter, the end offset of the next line.
 43	 *
 44	 * @param offset the offset whose line end offset must be computed
 45	 * @return the line end offset for the given offset
 46	 * @exception BadLocationException if offset is invalid in the current document
 47	 */
 48	protected int endOfLineOf(int offset) throws BadLocationException {
 49
 50		IRegion info = fDocument.getLineInformationOfOffset(offset);
 51		if (offset <= info.getOffset() + info.getLength())
 52			return info.getOffset() + info.getLength();
 53
 54		int line = fDocument.getLineOfOffset(offset);
 55		try {
 56			info = fDocument.getLineInformation(line + 1);
 57			return info.getOffset() + info.getLength();
 58		} catch (BadLocationException x) {
 59			return fDocument.getLength();
 60		}
 61	}
 62
 63	/**
 64	 * @see IPresentationDamager#getDamageRegion(ITypedRegion, DocumentEvent, boolean)
 65	 */
 66	public IRegion getDamageRegion(
 67		ITypedRegion partition,
 68		DocumentEvent event,
 69		boolean documentPartitioningChanged) {
 70		if (!documentPartitioningChanged) {
 71			try {
 72
 73				IRegion info =
 74					fDocument.getLineInformationOfOffset(event.getOffset());
 75				int start = Math.max(partition.getOffset(), info.getOffset());
 76
 77				int end =
 78					event.getOffset()
 79						+ (event.getText() == null
 80							? event.getLength()
 81							: event.getText().length());
 82
 83				if (info.getOffset() <= end
 84					&& end <= info.getOffset() + info.getLength()) {
 85					// optimize the case of the same line
 86					end = info.getOffset() + info.getLength();
 87				} else
 88					end = endOfLineOf(end);
 89
 90				end =
 91					Math.min(
 92						partition.getOffset() + partition.getLength(),
 93						end);
 94				return new Region(start, end - start);
 95
 96			} catch (BadLocationException x) {
 97			}
 98		}
 99
100		return partition;
101	}
102
103	/**
104	 * @see IPresentationRepairer#createPresentation(TextPresentation, ITypedRegion)
105	 */
106	public void createPresentation(
107		TextPresentation presentation,
108		ITypedRegion region) {
109		addRange(
110			presentation,
111			region.getOffset(),
112			region.getLength(),
113			fDefaultTextAttribute);
114	}
115
116	/**
117	 * Adds style information to the given text presentation.
118	 *
119	 * @param presentation the text presentation to be extended
120	 * @param offset the offset of the range to be styled
121	 * @param length the length of the range to be styled
122	 * @param attr the attribute describing the style of the range to be styled
123	 */
124	protected void addRange(
125		TextPresentation presentation,
126		int offset,
127		int length,
128		TextAttribute attr) {
129		if (attr != null)
130			presentation.addStyleRange(
131				new StyleRange(
132					offset,
133					length,
134					attr.getForeground(),
135					attr.getBackground(),
136					attr.getStyle()));
137	}
138}