ErlMergeViewer.java

/*******************************************************************************
 * Copyright (c) 2005 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
 *     QNX Software System
 *******************************************************************************/
package org.erlide.ui.internal.compare;

import org.eclipse.compare.CompareConfiguration;
import org.eclipse.compare.contentmergeviewer.TextMergeViewer;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceConverter;
import org.eclipse.jface.text.IDocumentPartitioner;
import org.eclipse.jface.text.TextViewer;
import org.eclipse.jface.text.source.SourceViewer;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.ui.texteditor.AbstractTextEditor;
import org.erlide.ui.editors.erl.EditorConfiguration;
import org.erlide.ui.editors.erl.ErlangDocumentSetupParticipant;
import org.erlide.ui.editors.erl.ErlangEditor;
import org.erlide.ui.editors.erl.ErlangSourceViewerConfiguration;
import org.erlide.ui.editors.erl.scanner.IErlangPartitions;
import org.erlide.ui.internal.ErlideUIPlugin;
import org.erlide.ui.util.ColorManager;

public class ErlMergeViewer extends TextMergeViewer {

    private IPropertyChangeListener fPreferenceChangeListener;

    private final IPreferenceStore fPreferenceStore;

    private boolean fUseSystemColors;

    private ErlangSourceViewerConfiguration fSourceViewerConfiguration;

    private IDocumentPartitioner documentPartitioner = null;

    public ErlMergeViewer(final Composite parent, final int styles,
            final CompareConfiguration mp) {
        super(parent, styles, mp);
        fPreferenceStore = ErlangEditor.getErlangEditorPreferenceStore();
        if (fPreferenceStore != null) {
            fPreferenceChangeListener = new IPropertyChangeListener() {

                @Override
                public void propertyChange(final PropertyChangeEvent event) {
                    handlePropertyChange(event);
                }
            };
            fPreferenceStore.addPropertyChangeListener(fPreferenceChangeListener);

            fUseSystemColors = fPreferenceStore.getBoolean(
                    AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT);
            if (!fUseSystemColors) {
                final RGB bg = createColor(fPreferenceStore,
                        AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND);
                setBackgroundColor(bg);
                final RGB fg = createColor(fPreferenceStore,
                        AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND);
                setForegroundColor(fg);
            }
        }
    }

    @Override
    protected void handleDispose(final DisposeEvent event) {
        if (fPreferenceChangeListener != null) {
            fPreferenceStore.removePropertyChangeListener(fPreferenceChangeListener);
            fPreferenceChangeListener = null;
        }
        super.handleDispose(event);
    }

    protected void handlePropertyChange(final PropertyChangeEvent event) {

        final String key = event.getProperty();

        if (key.equals(AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND)) {

            if (!fUseSystemColors) {
                final RGB bg = createColor(fPreferenceStore,
                        AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND);
                setBackgroundColor(bg);
            }

        } else if (key
                .equals(AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT)) {

            fUseSystemColors = fPreferenceStore.getBoolean(
                    AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND_SYSTEM_DEFAULT);
            if (fUseSystemColors) {
                setBackgroundColor(null);
                setForegroundColor(null);
            } else {
                final RGB bg = createColor(fPreferenceStore,
                        AbstractTextEditor.PREFERENCE_COLOR_BACKGROUND);
                setBackgroundColor(bg);
                final RGB fg = createColor(fPreferenceStore,
                        AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND);
                setForegroundColor(fg);
            }
        } else if (key.equals(AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND)) {

            if (!fUseSystemColors) {
                final RGB fg = createColor(fPreferenceStore,
                        AbstractTextEditor.PREFERENCE_COLOR_FOREGROUND);
                setForegroundColor(fg);
            }
        }

        // if (getSourceViewerConfiguration().affectsBehavior(event)) {
        // getSourceViewerConfiguration().adaptToPreferenceChange(event);
        // invalidateTextPresentation();
        // }
    }

    /**
     * Creates a color from the information stored in the given preference
     * store. Returns <code>null</code> if there is no such information
     * available.
     */
    private static RGB createColor(final IPreferenceStore store, final String key) {
        if (!store.contains(key)) {
            return null;
        }
        if (store.isDefault(key)) {
            return PreferenceConverter.getDefaultColor(store, key);
        }
        return PreferenceConverter.getColor(store, key);
    }

    private ErlangSourceViewerConfiguration getSourceViewerConfiguration() {
        if (fSourceViewerConfiguration == null) {
            fSourceViewerConfiguration = new EditorConfiguration(fPreferenceStore, null,
                    new ColorManager());
        }
        return fSourceViewerConfiguration;
    }

    @Override
    public String getTitle() {
        return ErlideUIPlugin.getResourceString("Erlang Source Compare");
    }

    @Override
    protected void configureTextViewer(final TextViewer textViewer) {
        if (textViewer instanceof SourceViewer) {
            ((SourceViewer) textViewer).configure(getSourceViewerConfiguration());
        }
    }

    @Override
    protected String getDocumentPartitioning() {
        return IErlangPartitions.ERLANG_PARTITIONING;
    }

    @Override
    protected IDocumentPartitioner getDocumentPartitioner() {
        if (documentPartitioner == null) {
            documentPartitioner = ErlangDocumentSetupParticipant
                    .createDocumentPartitioner();
        }
        return documentPartitioner;
        // return null;
    }

}