Package org.eclipse.jface.internal.text.html

Source Code of org.eclipse.jface.internal.text.html.HTMLTextPresenter

/*******************************************************************************
* Copyright (c) 2000, 2008 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.jface.internal.text.html;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.util.Iterator;

import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.graphics.Drawable;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.widgets.Display;

import org.eclipse.jface.internal.text.link.contentassist.LineBreakingReader;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.TextPresentation;


/**
* <p>
* Moved into this package from <code>org.eclipse.jface.internal.text.revisions</code>.</p>
*/
public class HTMLTextPresenter implements DefaultInformationControl.IInformationPresenter, DefaultInformationControl.IInformationPresenterExtension {

  private static final String LINE_DELIM= System.getProperty("line.separator", "\n"); //$NON-NLS-1$ //$NON-NLS-2$

  private int fCounter;
  private boolean fEnforceUpperLineLimit;

  public HTMLTextPresenter(boolean enforceUpperLineLimit) {
    super();
    fEnforceUpperLineLimit= enforceUpperLineLimit;
  }

  public HTMLTextPresenter() {
    this(true);
  }

  protected Reader createReader(String hoverInfo, TextPresentation presentation) {
    return new HTML2TextReader(new StringReader(hoverInfo), presentation);
  }

  protected void adaptTextPresentation(TextPresentation presentation, int offset, int insertLength) {

    int yoursStart= offset;
    int yoursEnd=   offset + insertLength -1;
    yoursEnd= Math.max(yoursStart, yoursEnd);

    Iterator e= presentation.getAllStyleRangeIterator();
    while (e.hasNext()) {

      StyleRange range= (StyleRange) e.next();

      int myStart= range.start;
      int myEnd=   range.start + range.length -1;
      myEnd= Math.max(myStart, myEnd);

      if (myEnd < yoursStart)
        continue;

      if (myStart < yoursStart)
        range.length += insertLength;
      else
        range.start += insertLength;
    }
  }

  private void append(StringBuffer buffer, String string, TextPresentation presentation) {

    int length= string.length();
    buffer.append(string);

    if (presentation != null)
      adaptTextPresentation(presentation, fCounter, length);

    fCounter += length;
  }

  private String getIndent(String line) {
    int length= line.length();

    int i= 0;
    while (i < length && Character.isWhitespace(line.charAt(i))) ++i;

    return (i == length ? line : line.substring(0, i)) + " "; //$NON-NLS-1$
  }

  /**
   * {@inheritDoc}
   *
   * @see org.eclipse.jface.text.DefaultInformationControl.IInformationPresenter#updatePresentation(org.eclipse.swt.widgets.Display, java.lang.String, org.eclipse.jface.text.TextPresentation, int, int)
   * @deprecated
   */
  public String updatePresentation(Display display, String hoverInfo, TextPresentation presentation, int maxWidth, int maxHeight) {
    return updatePresentation((Drawable)display, hoverInfo, presentation, maxWidth, maxHeight);
  }

  /*
   * @see IHoverInformationPresenterExtension#updatePresentation(Drawable drawable, String, TextPresentation, int, int)
   * @since 3.2
   */
  public String updatePresentation(Drawable drawable, String hoverInfo, TextPresentation presentation, int maxWidth, int maxHeight) {

    if (hoverInfo == null)
      return null;

    GC gc= new GC(drawable);
    try {

      StringBuffer buffer= new StringBuffer();
      int maxNumberOfLines= Math.round(maxHeight / gc.getFontMetrics().getHeight());

      fCounter= 0;
      LineBreakingReader reader= new LineBreakingReader(createReader(hoverInfo, presentation), gc, maxWidth);

      boolean lastLineFormatted= false;
      String lastLineIndent= null;

      String line=reader.readLine();
      boolean lineFormatted= reader.isFormattedLine();
      boolean firstLineProcessed= false;

      while (line != null) {

        if (fEnforceUpperLineLimit && maxNumberOfLines <= 0)
          break;

        if (firstLineProcessed) {
          if (!lastLineFormatted)
            append(buffer, LINE_DELIM, null);
          else {
            append(buffer, LINE_DELIM, presentation);
            if (lastLineIndent != null)
              append(buffer, lastLineIndent, presentation);
          }
        }

        append(buffer, line, null);
        firstLineProcessed= true;

        lastLineFormatted= lineFormatted;
        if (!lineFormatted)
          lastLineIndent= null;
        else if (lastLineIndent == null)
          lastLineIndent= getIndent(line);

        line= reader.readLine();
        lineFormatted= reader.isFormattedLine();

        maxNumberOfLines--;
      }

      if (line != null) {
        append(buffer, LINE_DELIM, lineFormatted ? presentation : null);
        append(buffer, HTMLMessages.getString("HTMLTextPresenter.ellipse"), presentation); //$NON-NLS-1$
      }

      return trim(buffer, presentation);

    } catch (IOException e) {

      // ignore TODO do something else?
      return null;

    } finally {
      gc.dispose();
    }
  }

  private String trim(StringBuffer buffer, TextPresentation presentation) {

    int length= buffer.length();

    int end= length -1;
    while (end >= 0 && Character.isWhitespace(buffer.charAt(end)))
      -- end;

    if (end == -1)
      return ""; //$NON-NLS-1$

    if (end < length -1)
      buffer.delete(end + 1, length);
    else
      end= length;

    int start= 0;
    while (start < end && Character.isWhitespace(buffer.charAt(start)))
      ++ start;

    buffer.delete(0, start);
    presentation.setResultWindow(new Region(start, buffer.length()));
    return buffer.toString();
  }
}
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