bundles/org.eclipse.wst.jsdt.debug.ui/src/org/eclipse/wst/jsdt/debug/internal/ui/source/JavaScriptSourceViewer.java

/*******************************************************************************
 * Copyright (c) 2010 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.wst.jsdt.debug.internal.ui.source;

import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceConverter;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.contentassist.IContentAssistant;
import org.eclipse.jface.text.source.IOverviewRuler;
import org.eclipse.jface.text.source.IVerticalRuler;
import org.eclipse.jface.text.source.SourceViewer;
import org.eclipse.jface.text.source.SourceViewerConfiguration;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.texteditor.AbstractTextEditor;
import org.eclipse.wst.jsdt.debug.internal.ui.display.JavaScriptDebugViewerConfiguration;

/**
 * A source viewer configured to display JavaScript source. This
 * viewer obeys the font and color preferences specified in
 * the JavaScript UI plugin.
 */
public class JavaScriptSourceViewer extends SourceViewer implements IPropertyChangeListener {
	
	private Font fFont;
	private Color fBackgroundColor;
	private Color fForegroundColor;
	private IPreferenceStore fStore;
	private JavaScriptDebugViewerConfiguration fConfiguration;


	/**
	 * Constructor
	 * @param parent
	 * @param ruler
	 * @param styles
	 */
	public JavaScriptSourceViewer(Composite parent, IVerticalRuler ruler, int styles) {
		this(parent, ruler, null, false, styles | SWT.LEFT_TO_RIGHT);
	}

	/**
	 * Constructor
	 * @param parent
	 * @param ruler
	 * @param overviewRuler
	 * @param isOverviewRulerVisible
	 * @param styles
	 */
	public JavaScriptSourceViewer(Composite parent, IVerticalRuler ruler, IOverviewRuler overviewRuler, boolean isOverviewRulerVisible, int styles) {
		super(parent, ruler, overviewRuler, isOverviewRulerVisible, styles | SWT.LEFT_TO_RIGHT);
	}
	
	/**
	 * Updates the viewer's font to match the preferences.
	 */
	private void updateViewerFont() {
		IPreferenceStore store= getPreferenceStore();
		if (store != null) {
			FontData data= null;
			if (store.contains(JFaceResources.TEXT_FONT) && !store.isDefault(JFaceResources.TEXT_FONT)) {
				data= PreferenceConverter.getFontData(store, JFaceResources.TEXT_FONT);
			} else {
				data= PreferenceConverter.getDefaultFontData(store, JFaceResources.TEXT_FONT);
			}
			if (data != null) {
				Font font= new Font(getTextWidget().getDisplay(), data);
				applyFont(font);
				if (getFont() != null) {
					getFont().dispose();
				}
				setFont(font);
				return;
			}
		}
		// if all the preferences failed
		applyFont(JFaceResources.getTextFont());
	}
	
	/**
	 * Sets the current font.
	 * 
	 * @param font the new font
	 */
	private void setFont(Font font) {
		fFont = font;
	}
	
	/**
	 * Returns the current font.
	 * 
	 * @return the current font
	 */
	private Font getFont() {
		return fFont;
	}
	
	/**
	 * Sets the font for the given viewer sustaining selection and scroll position.
	 * 
	 * @param font the font
	 */
	private void applyFont(Font font) {
		IDocument doc= getDocument();
		if (doc != null && doc.getLength() > 0) {
			Point selection= getSelectedRange();
			int topIndex= getTopIndex();
			
			StyledText styledText= getTextWidget();
			styledText.setRedraw(false);
			
			styledText.setFont(font);
			setSelectedRange(selection.x , selection.y);
			setTopIndex(topIndex);
			
			styledText.setRedraw(true);
		} else {
			getTextWidget().setFont(font);
		}
	}
	
	/**
	 * Updates the given viewer's colors to match the preferences.
	 */
	public void updateViewerColors() {
		IPreferenceStore store= getPreferenceStore();
		if (store != null) {
			StyledText styledText= getTextWidget();
			Color color= store.getBoolean(AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT)
				? null
				: createColor(store, AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND, styledText.getDisplay());
			styledText.setForeground(color);
			if (getForegroundColor() != null) {
				getForegroundColor().dispose();
			}
			setForegroundColor(color);
			
			color= store.getBoolean(AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT)
				? null
				: createColor(store, AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND, styledText.getDisplay());
			styledText.setBackground(color);
			if (getBackgroundColor() != null) {
				getBackgroundColor().dispose();
			}
			setBackgroundColor(color);
		}
	}
	
	/**
	 * Creates a color from the information stored in the given preference store.
	 * Returns <code>null</code> if there is no such information available.
	 */
	private Color createColor(IPreferenceStore store, String key, Display display) {
		RGB rgb = null;
		if (store.contains(key)) {
			if (store.isDefault(key)) {
				rgb= PreferenceConverter.getDefaultColor(store, key);
			} else {
				rgb= PreferenceConverter.getColor(store, key);
			}
			if (rgb != null) {
				return new Color(display, rgb);
			}
		}
		return null;
	}
	
	/**
	 * Returns the current background color.
	 * 
	 * @return the current background color
	 */
	protected Color getBackgroundColor() {
		return fBackgroundColor;
	}

	/**
	 * Sets the current background color.
	 * 
	 * @param backgroundColor the new background color
	 */
	protected void setBackgroundColor(Color backgroundColor) {
		fBackgroundColor = backgroundColor;
	}

	/**
	 * Returns the current foreground color.
	 * 
	 * @return the current foreground color
	 */
	protected Color getForegroundColor() {
		return fForegroundColor;
	}

	/**
	 * Sets the current foreground color.
	 * 
	 * @param foregroundColor the new foreground color
	 */
	protected void setForegroundColor(Color foregroundColor) {
		fForegroundColor = foregroundColor;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.util.IPropertyChangeListener#propertyChange(org.eclipse.jface.util.PropertyChangeEvent)
	 */
	public void propertyChange(PropertyChangeEvent event) {
		String property= event.getProperty();
		
		if (JFaceResources.TEXT_FONT.equals(property)) {
			updateViewerFont();
		}
		if (AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND.equals(property) || AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND_SYSTEM_DEFAULT.equals(property) ||
			AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND.equals(property) ||	AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT.equals(property)) {
			updateViewerColors();
		}
		if (fConfiguration != null) {
			if (fConfiguration.affectsTextPresentation(event)) {
				fConfiguration.handlePropertyChangeEvent(event);
				invalidateTextPresentation();
			}
		}
	}
	
	/**
	 * Returns the current content assistant.
	 * 
	 * @return the current content assistant
	 */
	public IContentAssistant getContentAssistant() {
		return fContentAssistant;
	}

	/**
	 * Disposes the system resources currently in use by this viewer.
	 */
	public void dispose() {
		if (getFont() != null) {
			getFont().dispose();
			setFont(null);
		}
		if (getBackgroundColor() != null) {
			getBackgroundColor().dispose();
			setBackgroundColor(null);
		}
		if (getForegroundColor() != null) {
			getForegroundColor().dispose();
			setForegroundColor(null);
		}
		if (fStore != null) {
			fStore.removePropertyChangeListener(this);
			fStore = null;
		}
	}

	/* (non-Javadoc)
	 * @see org.eclipse.jface.text.source.SourceViewer#configure(org.eclipse.jface.text.source.SourceViewerConfiguration)
	 */
	public void configure(SourceViewerConfiguration configuration) {
		super.configure(configuration);
		if (fStore != null) {
			fStore.removePropertyChangeListener(this);
			fStore = null;
		}
		if (configuration instanceof JavaScriptDebugViewerConfiguration) {
			fConfiguration = (JavaScriptDebugViewerConfiguration) configuration;
			fStore = fConfiguration.getTextPreferenceStore();
			fStore.addPropertyChangeListener(this);
		}
		updateViewerFont();
		updateViewerColors();
	}

	/**
	 * Returns the preference store used to configure this source viewer or
	 * <code>null</code> if none;
	 */
	private IPreferenceStore getPreferenceStore() {
		return fStore;
	}
}