org.eclipse.ui.cheatsheets/src/org/eclipse/ui/internal/cheatsheets/CheatSheetPlugin.java - platform/eclipse.platform.ua - Git at Google

 /*******************************************************************************
  *  Copyright (c) 2002, 2016 IBM Corporation and others.
  *
  *  This program and the accompanying materials
  *  are made available under the terms of the Eclipse Public License 2.0
  *  which accompanies this distribution, and is available at
  *  https://www.eclipse.org/legal/epl-2.0/
  *
  *  SPDX-License-Identifier: EPL-2.0
  *
  *  Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.cheatsheets;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;

 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;

 import org.eclipse.core.runtime.FileLocator;
 import org.eclipse.core.runtime.IPath;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Path;
 import org.eclipse.core.runtime.SafeRunner;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.help.internal.entityresolver.LocalEntityResolver;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.resource.ImageRegistry;
 import org.eclipse.jface.util.SafeRunnable;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.ui.IMemento;
 import org.eclipse.ui.XMLMemento;
 import org.eclipse.ui.internal.cheatsheets.registry.CheatSheetRegistryReader;
 import org.eclipse.ui.plugin.AbstractUIPlugin;
 import org.osgi.framework.Bundle;
 import org.osgi.framework.BundleContext;

 /**
  * The main plugin class for cheat sheets.
  */

 public class CheatSheetPlugin extends AbstractUIPlugin {

 	public final static String PLUGIN_ID = "org.eclipse.help.base"; //$NON-NLS-1$

 	//The shared instance of this plugin.
 	static CheatSheetPlugin plugin;

 	//Resource bundle.
 	//private boolean resourceBundleInitialized = false;
 	//private ResourceBundle resourceBundle;
 	private CheatSheetHistory history = null;
 	private DocumentBuilder documentBuilder = null;

 	private static final String HISTORY_FILENAME = "history.xml"; //$NON-NLS-1$
 	private static final String MEMENTO_TAG_CHEATSHEET = "cheatsheet"; //$NON-NLS-1$
 	private static final String MEMENTO_TAG_VERSION = "version"; //$NON-NLS-1$
 	private static final String VERSION_STRING[] = { "0.0", "3.0.0" }; //$NON-NLS-1$ //$NON-NLS-2$
 	private static final String MEMENTO_TAG_CHEATSHEET_HISTORY = "cheatsheetHistory"; //$NON-NLS-1$

 	public static final IPath ICONS_PATH = new Path("$nl$/icons/"); //$NON-NLS-1$
 	public static final String T_OBJ = "obj16/"; //$NON-NLS-1$
 	public static final String T_ELCL = "elcl16/"; //$NON-NLS-1$
 	public static final String T_DLCL = "dlcl16/"; //$NON-NLS-1$
 	public static final String T_VIEW = "view16/"; //$NON-NLS-1$

 	/**
 	 * The constructor.
 	 */
 	public CheatSheetPlugin() {
 		super();
 	}

 	/**
 	 * Returns the shared instance.
 	 */
 	public static CheatSheetPlugin getPlugin() {
 		return plugin;
 	}

 	/**
 	 * Returns the image in Cheat Sheet's image registry with the given key,
 	 * or <code>null</code> if none.
 	 * Convenience method equivalent to
 	 * <pre>
 	 * CheatSheetPlugin.getImageRegistry().get(key)
 	 * </pre>
 	 *
 	 * @param key the key
 	 * @return the image, or <code>null</code> if none
 	 */
 	public Image getImage(String key) {
 		Image image = getImageRegistry().get(key);
 		return image;
 	}

 	/**
 	 * Returns the CheatSheetHistory
 	 */
 	public CheatSheetHistory getCheatSheetHistory() {
 		if (history == null) {
 			history = new CheatSheetHistory(CheatSheetRegistryReader.getInstance());
 			restoreCheatSheetHistory();
 		}
 		return history;
 	}

 	/**
 	 * Get a file from the state folder.
 	 */
 	private File getCheatSheetStateFile(String filename) {
 		IPath path = CheatSheetPlugin.getPlugin().getStateLocation();
 		path = path.append(filename);
 		return path.toFile();
 	}

 	/**
 	 * Returns the DocumentBuilder to be used by the cheat sheets.
 	 */
 	public DocumentBuilder getDocumentBuilder() {
 		if(documentBuilder == null) {
 			try {
 				documentBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
 				documentBuilder.setEntityResolver(new LocalEntityResolver());
 			} catch (Exception e) {
 				IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, Messages.ERROR_CREATING_DOCUMENT_BUILDER, e);
 				CheatSheetPlugin.getPlugin().getLog().log(status);
 			}
 		}
 		return documentBuilder;
 	}

 	/**
 	 * Logs an Error message with an exception.
 	 */
 	public static synchronized void logError(String message, Throwable ex) {
 		if (message == null)
 			message = ""; //$NON-NLS-1$
 		Status errorStatus = new Status(IStatus.ERROR, PLUGIN_ID, IStatus.OK,
 				message, ex);
 		CheatSheetPlugin.getPlugin().getLog().log(errorStatus);
 	}

 	@Override
 	protected void initializeImageRegistry(ImageRegistry reg) {
 		IPath path = ICONS_PATH.append(T_OBJ).append("cheatsheet_obj.gif");//$NON-NLS-1$
 		ImageDescriptor imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_OBJ, imageDescriptor);

 		path = ICONS_PATH.append(T_OBJ).append("skip_status.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_ITEM_SKIP, imageDescriptor);

 		path = ICONS_PATH.append(T_OBJ).append("complete_status.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_ITEM_COMPLETE, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("linkto_help.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_ITEM_HELP, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("start_cheatsheet.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_START, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("restart_cheatsheet.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_RESTART, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("start_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_START, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("skip_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_SKIP, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("complete_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_COMPLETE, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("restart_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_RESTART, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("return_to_start.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_RETURN, imageDescriptor);

 		path = ICONS_PATH.append(T_OBJ).append("error.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.ERROR, imageDescriptor);

 		// Images used by composites

 		path = ICONS_PATH.append(T_OBJ).append("composite_obj.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.COMPOSITE_OBJ, imageDescriptor);

 		path = ICONS_PATH.append(T_OBJ).append("information.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.INFORMATION, imageDescriptor);

 		path = ICONS_PATH.append(T_OBJ).append("warning.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.WARNING, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("start_ccs_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.COMPOSITE_TASK_START, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("skip_ccs_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.COMPOSITE_TASK_SKIP, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("review_ccs_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.COMPOSITE_TASK_REVIEW, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("goto_ccs_task.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.COMPOSITE_GOTO_TASK, imageDescriptor);

 		path = ICONS_PATH.append(T_ELCL).append("restart_all.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.COMPOSITE_RESTART_ALL, imageDescriptor);

 		path = ICONS_PATH.append(T_VIEW).append("cheatsheet_view.gif");//$NON-NLS-1$
 		imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
 		reg.put(ICheatSheetResource.CHEATSHEET_VIEW, imageDescriptor);
 	}

 	/**
 	 * Restores the state of the previously saved cheatsheet history
 	 */
 	private void restoreCheatSheetHistory() {
 		SafeRunner.run(new SafeRunnable() {
 			@Override
 			public void run() {
 				IMemento memento;
 				memento = readMemento(HISTORY_FILENAME);
 				if (memento != null) {
 					IMemento childMem = memento.getChild(MEMENTO_TAG_CHEATSHEET_HISTORY);
 					if (childMem != null) {
 						history.restoreState(childMem);
 					}
 				}
 			}
 			@Override
 			public void handleException(Throwable e) {
 				String message = Messages.ERROR_READING_STATE_FILE;
 				IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
 				CheatSheetPlugin.getPlugin().getLog().log(status);
 			}
 		});
 	}

 	/**
 	 * Read a memento from the state directory for the cheatsheets plugin
 	 * @param filename A simple filename
 	 * @return A memento read from the state directory or null if the memento could not be read
 	 */
 	public XMLMemento readMemento(String filename) {
 		XMLMemento memento;
 		InputStreamReader reader = null;

 		try {
 			// Read the cheatsheet state file.
 			final File stateFile = getCheatSheetStateFile(filename);

 			FileInputStream input = new FileInputStream(stateFile);
 			reader = new InputStreamReader(input, StandardCharsets.UTF_8);
 			memento = XMLMemento.createReadRoot(reader);


 		} catch (FileNotFoundException e) {
 			memento = null;
 			// Do nothing, the file will not exist the first time the workbench in used.
 		} catch (Exception e) {
 			String message = Messages.ERROR_READING_STATE_FILE;
 			IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
 			CheatSheetPlugin.getPlugin().getLog().log(status);
 			memento = null;
 		} finally {
 			try {
 				if (reader != null)
 					reader.close();
 			} catch (IOException e) {
 				// Not much to do, just catch the exception and keep going.
 				String message = Messages.ERROR_READING_STATE_FILE;
 				IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
 				CheatSheetPlugin.getPlugin().getLog().log(status);
 			}
 		}
 		return memento;
 	}

 	/**
 	 * Saves the current cheatsheet history so it can be restored later on
 	 */
 	private void saveCheatSheetHistory() {
 		SafeRunner.run(new SafeRunnable() {
 			@Override
 			public void run() {
 				XMLMemento memento = XMLMemento.createWriteRoot(MEMENTO_TAG_CHEATSHEET);

 				// Save the version number.
 				memento.putString(MEMENTO_TAG_VERSION, VERSION_STRING[1]);

 				// Save perspective history.
 				getCheatSheetHistory().saveState(memento.createChild(MEMENTO_TAG_CHEATSHEET_HISTORY));

 				IStatus status = saveMemento(memento, HISTORY_FILENAME);
 				if (!status.isOK()) {
 					CheatSheetPlugin.getPlugin().getLog().log(status);
 				}
 			}
 			@Override
 			public void handleException(Throwable e) {
 				String message = Messages.ERROR_WRITING_STATE_FILE;
 				IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
 				CheatSheetPlugin.getPlugin().getLog().log(status);
 			}
 		});
 	}

 	/**
 	 * Save the memento to a file in this plugins state area
 	 * @param memento The memento to save
 	 * @param filename A simple filename
 	 * @return OK_Status if the memento was saved without error, otherwise an error
 	 * status
 	 */
 	public IStatus saveMemento(XMLMemento memento, String filename) {
 		// Save the IMemento to a file.
 		File stateFile = getCheatSheetStateFile(filename);
 		OutputStreamWriter writer = null;
 		try {
 			FileOutputStream stream = new FileOutputStream(stateFile);
 			writer = new OutputStreamWriter(stream, StandardCharsets.UTF_8);
 			memento.save(writer);
 			return Status.OK_STATUS;
 		} catch (IOException e) {
 			stateFile.delete();
 			String message = Messages.ERROR_WRITING_STATE_FILE;
 			IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
 			return status;
 		} finally {
 			try {
 				if (writer != null)
 					writer.close();
 			} catch (IOException e) {
 				String message = Messages.ERROR_WRITING_STATE_FILE;
 				IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
 				CheatSheetPlugin.getPlugin().getLog().log(status);
 			}
 		}
 	}

 	@Override
 	public void start(BundleContext context) throws Exception {
 		super.start(context);

 		plugin = this;

 		// allow the MRU history to be lazily initialized by getCheatSheetHistory
 	}

 	@Override
 	public void stop(BundleContext context) throws Exception {
 		super.stop(context);

 		// save the MRU history if necessary
 		// if we never restored history, let existing memento stand
 		if (history != null) {
 			saveCheatSheetHistory();
 		}

 		CheatSheetRegistryReader.getInstance().stop();
 	}

 	/*
 	 * Since 3.1.1. Load from icon paths with $NL$
 	 */
 	public static ImageDescriptor createImageDescriptor(Bundle bundle, IPath path) {
 		URL url= FileLocator.find(bundle, path, null);
 		if (url != null) {
 			return ImageDescriptor.createFromURL(url);
 		}
 		return null;
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2002, 2016 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.ui.internal.cheatsheets;

	import java.io.File;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.FileOutputStream;
	import java.io.IOException;
	import java.io.InputStreamReader;
	import java.io.OutputStreamWriter;
	import java.net.URL;
	import java.nio.charset.StandardCharsets;

	import javax.xml.parsers.DocumentBuilder;
	import javax.xml.parsers.DocumentBuilderFactory;

	import org.eclipse.core.runtime.FileLocator;
	import org.eclipse.core.runtime.IPath;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Path;
	import org.eclipse.core.runtime.SafeRunner;
	import org.eclipse.core.runtime.Status;
	import org.eclipse.help.internal.entityresolver.LocalEntityResolver;
	import org.eclipse.jface.resource.ImageDescriptor;
	import org.eclipse.jface.resource.ImageRegistry;
	import org.eclipse.jface.util.SafeRunnable;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.ui.IMemento;
	import org.eclipse.ui.XMLMemento;
	import org.eclipse.ui.internal.cheatsheets.registry.CheatSheetRegistryReader;
	import org.eclipse.ui.plugin.AbstractUIPlugin;
	import org.osgi.framework.Bundle;
	import org.osgi.framework.BundleContext;

	/**
	* The main plugin class for cheat sheets.
	*/

	public class CheatSheetPlugin extends AbstractUIPlugin {

	public final static String PLUGIN_ID = "org.eclipse.help.base"; //$NON-NLS-1$

	//The shared instance of this plugin.
	static CheatSheetPlugin plugin;

	//Resource bundle.
	//private boolean resourceBundleInitialized = false;
	//private ResourceBundle resourceBundle;
	private CheatSheetHistory history = null;
	private DocumentBuilder documentBuilder = null;

	private static final String HISTORY_FILENAME = "history.xml"; //$NON-NLS-1$
	private static final String MEMENTO_TAG_CHEATSHEET = "cheatsheet"; //$NON-NLS-1$
	private static final String MEMENTO_TAG_VERSION = "version"; //$NON-NLS-1$
	private static final String VERSION_STRING[] = { "0.0", "3.0.0" }; //$NON-NLS-1$ //$NON-NLS-2$
	private static final String MEMENTO_TAG_CHEATSHEET_HISTORY = "cheatsheetHistory"; //$NON-NLS-1$

	public static final IPath ICONS_PATH = new Path("$nl$/icons/"); //$NON-NLS-1$
	public static final String T_OBJ = "obj16/"; //$NON-NLS-1$
	public static final String T_ELCL = "elcl16/"; //$NON-NLS-1$
	public static final String T_DLCL = "dlcl16/"; //$NON-NLS-1$
	public static final String T_VIEW = "view16/"; //$NON-NLS-1$

	/**
	* The constructor.
	*/
	public CheatSheetPlugin() {
	super();
	}

	/**
	* Returns the shared instance.
	*/
	public static CheatSheetPlugin getPlugin() {
	return plugin;
	}

	/**
	* Returns the image in Cheat Sheet's image registry with the given key,
	* or <code>null</code> if none.
	* Convenience method equivalent to
	* <pre>
	* CheatSheetPlugin.getImageRegistry().get(key)
	* </pre>
	*
	* @param key the key
	* @return the image, or <code>null</code> if none
	*/
	public Image getImage(String key) {
	Image image = getImageRegistry().get(key);
	return image;
	}

	/**
	* Returns the CheatSheetHistory
	*/
	public CheatSheetHistory getCheatSheetHistory() {
	if (history == null) {
	history = new CheatSheetHistory(CheatSheetRegistryReader.getInstance());
	restoreCheatSheetHistory();
	}
	return history;
	}

	/**
	* Get a file from the state folder.
	*/
	private File getCheatSheetStateFile(String filename) {
	IPath path = CheatSheetPlugin.getPlugin().getStateLocation();
	path = path.append(filename);
	return path.toFile();
	}

	/**
	* Returns the DocumentBuilder to be used by the cheat sheets.
	*/
	public DocumentBuilder getDocumentBuilder() {
	if(documentBuilder == null) {
	try {
	documentBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
	documentBuilder.setEntityResolver(new LocalEntityResolver());
	} catch (Exception e) {
	IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, Messages.ERROR_CREATING_DOCUMENT_BUILDER, e);
	CheatSheetPlugin.getPlugin().getLog().log(status);
	}
	}
	return documentBuilder;
	}

	/**
	* Logs an Error message with an exception.
	*/
	public static synchronized void logError(String message, Throwable ex) {
	if (message == null)
	message = ""; //$NON-NLS-1$
	Status errorStatus = new Status(IStatus.ERROR, PLUGIN_ID, IStatus.OK,
	message, ex);
	CheatSheetPlugin.getPlugin().getLog().log(errorStatus);
	}

	@Override
	protected void initializeImageRegistry(ImageRegistry reg) {
	IPath path = ICONS_PATH.append(T_OBJ).append("cheatsheet_obj.gif");//$NON-NLS-1$
	ImageDescriptor imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_OBJ, imageDescriptor);

	path = ICONS_PATH.append(T_OBJ).append("skip_status.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_ITEM_SKIP, imageDescriptor);

	path = ICONS_PATH.append(T_OBJ).append("complete_status.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_ITEM_COMPLETE, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("linkto_help.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_ITEM_HELP, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("start_cheatsheet.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_START, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("restart_cheatsheet.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_RESTART, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("start_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_START, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("skip_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_SKIP, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("complete_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_COMPLETE, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("restart_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_ITEM_BUTTON_RESTART, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("return_to_start.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_RETURN, imageDescriptor);

	path = ICONS_PATH.append(T_OBJ).append("error.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.ERROR, imageDescriptor);

	// Images used by composites

	path = ICONS_PATH.append(T_OBJ).append("composite_obj.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.COMPOSITE_OBJ, imageDescriptor);

	path = ICONS_PATH.append(T_OBJ).append("information.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.INFORMATION, imageDescriptor);

	path = ICONS_PATH.append(T_OBJ).append("warning.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.WARNING, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("start_ccs_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.COMPOSITE_TASK_START, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("skip_ccs_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.COMPOSITE_TASK_SKIP, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("review_ccs_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.COMPOSITE_TASK_REVIEW, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("goto_ccs_task.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.COMPOSITE_GOTO_TASK, imageDescriptor);

	path = ICONS_PATH.append(T_ELCL).append("restart_all.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.COMPOSITE_RESTART_ALL, imageDescriptor);

	path = ICONS_PATH.append(T_VIEW).append("cheatsheet_view.gif");//$NON-NLS-1$
	imageDescriptor = createImageDescriptor(getPlugin().getBundle(), path);
	reg.put(ICheatSheetResource.CHEATSHEET_VIEW, imageDescriptor);
	}

	/**
	* Restores the state of the previously saved cheatsheet history
	*/
	private void restoreCheatSheetHistory() {
	SafeRunner.run(new SafeRunnable() {
	@Override
	public void run() {
	IMemento memento;
	memento = readMemento(HISTORY_FILENAME);
	if (memento != null) {
	IMemento childMem = memento.getChild(MEMENTO_TAG_CHEATSHEET_HISTORY);
	if (childMem != null) {
	history.restoreState(childMem);
	}
	}
	}
	@Override
	public void handleException(Throwable e) {
	String message = Messages.ERROR_READING_STATE_FILE;
	IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
	CheatSheetPlugin.getPlugin().getLog().log(status);
	}
	});
	}

	/**
	* Read a memento from the state directory for the cheatsheets plugin
	* @param filename A simple filename
	* @return A memento read from the state directory or null if the memento could not be read
	*/
	public XMLMemento readMemento(String filename) {
	XMLMemento memento;
	InputStreamReader reader = null;

	try {
	// Read the cheatsheet state file.
	final File stateFile = getCheatSheetStateFile(filename);

	FileInputStream input = new FileInputStream(stateFile);
	reader = new InputStreamReader(input, StandardCharsets.UTF_8);
	memento = XMLMemento.createReadRoot(reader);


	} catch (FileNotFoundException e) {
	memento = null;
	// Do nothing, the file will not exist the first time the workbench in used.
	} catch (Exception e) {
	String message = Messages.ERROR_READING_STATE_FILE;
	IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
	CheatSheetPlugin.getPlugin().getLog().log(status);
	memento = null;
	} finally {
	try {
	if (reader != null)
	reader.close();
	} catch (IOException e) {
	// Not much to do, just catch the exception and keep going.
	String message = Messages.ERROR_READING_STATE_FILE;
	IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
	CheatSheetPlugin.getPlugin().getLog().log(status);
	}
	}
	return memento;
	}

	/**
	* Saves the current cheatsheet history so it can be restored later on
	*/
	private void saveCheatSheetHistory() {
	SafeRunner.run(new SafeRunnable() {
	@Override
	public void run() {
	XMLMemento memento = XMLMemento.createWriteRoot(MEMENTO_TAG_CHEATSHEET);

	// Save the version number.
	memento.putString(MEMENTO_TAG_VERSION, VERSION_STRING[1]);

	// Save perspective history.
	getCheatSheetHistory().saveState(memento.createChild(MEMENTO_TAG_CHEATSHEET_HISTORY));

	IStatus status = saveMemento(memento, HISTORY_FILENAME);
	if (!status.isOK()) {
	CheatSheetPlugin.getPlugin().getLog().log(status);
	}
	}
	@Override
	public void handleException(Throwable e) {
	String message = Messages.ERROR_WRITING_STATE_FILE;
	IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
	CheatSheetPlugin.getPlugin().getLog().log(status);
	}
	});
	}

	/**
	* Save the memento to a file in this plugins state area
	* @param memento The memento to save
	* @param filename A simple filename
	* @return OK_Status if the memento was saved without error, otherwise an error
	* status
	*/
	public IStatus saveMemento(XMLMemento memento, String filename) {
	// Save the IMemento to a file.
	File stateFile = getCheatSheetStateFile(filename);
	OutputStreamWriter writer = null;
	try {
	FileOutputStream stream = new FileOutputStream(stateFile);
	writer = new OutputStreamWriter(stream, StandardCharsets.UTF_8);
	memento.save(writer);
	return Status.OK_STATUS;
	} catch (IOException e) {
	stateFile.delete();
	String message = Messages.ERROR_WRITING_STATE_FILE;
	IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
	return status;
	} finally {
	try {
	if (writer != null)
	writer.close();
	} catch (IOException e) {
	String message = Messages.ERROR_WRITING_STATE_FILE;
	IStatus status = new Status(IStatus.ERROR, ICheatSheetResource.CHEAT_SHEET_PLUGIN_ID, IStatus.OK, message, e);
	CheatSheetPlugin.getPlugin().getLog().log(status);
	}
	}
	}

	@Override
	public void start(BundleContext context) throws Exception {
	super.start(context);

	plugin = this;

	// allow the MRU history to be lazily initialized by getCheatSheetHistory
	}

	@Override
	public void stop(BundleContext context) throws Exception {
	super.stop(context);

	// save the MRU history if necessary
	// if we never restored history, let existing memento stand
	if (history != null) {
	saveCheatSheetHistory();
	}

	CheatSheetRegistryReader.getInstance().stop();
	}

	/*
	* Since 3.1.1. Load from icon paths with $NL$
	*/
	public static ImageDescriptor createImageDescriptor(Bundle bundle, IPath path) {
	URL url= FileLocator.find(bundle, path, null);
	if (url != null) {
	return ImageDescriptor.createFromURL(url);
	}
	return null;
	}

	}