core/plugins/org.eclipse.dltk.debug.ui/src/org/eclipse/dltk/internal/debug/ui/ScriptDebugHover.java

/*******************************************************************************
 * Copyright (c) 2000, 2017 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
 *
 *******************************************************************************/
package org.eclipse.dltk.internal.debug.ui;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.debug.core.DebugException;
import org.eclipse.debug.core.model.IVariable;
import org.eclipse.debug.ui.DebugUITools;
import org.eclipse.dltk.core.ICodeAssist;
import org.eclipse.dltk.core.IField;
import org.eclipse.dltk.core.IModelElement;
import org.eclipse.dltk.dbgp.IDbgpProperty;
import org.eclipse.dltk.dbgp.commands.IDbgpPropertyCommands;
import org.eclipse.dltk.debug.core.model.IScriptStackFrame;
import org.eclipse.dltk.debug.core.model.IScriptValue;
import org.eclipse.dltk.debug.ui.DLTKDebugUIPlugin;
import org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation;
import org.eclipse.dltk.internal.debug.core.model.ScriptValue;
import org.eclipse.dltk.internal.ui.text.HTMLTextPresenter;
import org.eclipse.dltk.internal.ui.text.ScriptWordFinder;
import org.eclipse.dltk.ui.DLTKUIPlugin;
import org.eclipse.dltk.ui.text.hover.IScriptEditorTextHover;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextHoverExtension;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.swt.SWT;
import org.eclipse.ui.IEditorInput;
import org.eclipse.ui.IEditorPart;
import org.eclipse.ui.editors.text.EditorsUI;

public abstract class ScriptDebugHover
		implements IScriptEditorTextHover, ITextHoverExtension {

	private IEditorPart editor;

	@Override
	public void setEditor(IEditorPart editor) {
		this.editor = editor;
	}

	@Override
	public IRegion getHoverRegion(final ITextViewer textViewer, int offset) {
		return ScriptWordFinder.findWord(textViewer.getDocument(), offset);
	}

	/**
	 * Returns the stack frame in which to search for variables, or
	 * <code>null</code> if none.
	 *
	 * @return the stack frame in which to search for variables, or
	 *         <code>null</code> if none
	 */
	protected IScriptStackFrame getFrame() {
		IAdaptable adaptable = DebugUITools.getDebugContext();
		if (adaptable != null) {
			return adaptable.getAdapter(IScriptStackFrame.class);
		}
		return null;
	}

	@Override
	public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {
		IScriptStackFrame frame = getFrame();
		if (frame == null || editor == null)
			return null;

		IEditorInput input = editor.getEditorInput();
		Object element = DLTKUIPlugin.getDefault().getWorkingCopyManager()
				.getWorkingCopy(input);

		if (!(element instanceof ICodeAssist))
			return null;

		ICodeAssist codeAssist = (ICodeAssist) element;
		IModelElement[] resolve = null;
		try {
			resolve = codeAssist.codeSelect(hoverRegion.getOffset(),
					hoverRegion.getLength());

			IDbgpPropertyCommands propCmds = frame.getScriptThread()
					.getDbgpSession().getCoreCommands();

			for (int i = 0; i < resolve.length; i++) {
				IModelElement scriptElement = resolve[i];
				if (scriptElement instanceof IField) {
					IField field = (IField) scriptElement;
					String snippet = getFieldProperty(field);
					try {
						IDbgpProperty property = propCmds.getProperty(snippet);
						return getResultText(snippet,
								ScriptValue.createValue(frame, property));
					} catch (DebugException e) {
					}
				}
			}
		} catch (Exception e) {
		}
		return null;
	}

	protected String getFieldProperty(IField field) {
		String snippet = field.getElementName();
		return snippet;
	}

	protected String getResultText(String snippet, IScriptValue value)
			throws DebugException {
		String str = getModelPresentation().getText(value);
		return prepareHtml(snippet + " = " + str); //$NON-NLS-1$
	}

	protected String getVariableText(IVariable variable) throws DebugException {
		return prepareHtml(getModelPresentation().getText(variable));
	}

	protected String prepareHtml(String text) {
		StringBuffer buffer = new StringBuffer();
		buffer.append("<p><pre>"); //$NON-NLS-1$
		buffer.append(replaceHTMLChars(text));
		buffer.append("</pre></p>"); //$NON-NLS-1$
		if (buffer.length() > 0) {
			return buffer.toString();
		}

		return null;
	}

	/**
	 * Replaces reserved HTML characters in the given string with their escaped
	 * equivalents. This is to ensure that variable values containing reserved
	 * characters are correctly displayed.
	 */
	private static String replaceHTMLChars(String variableText) {
		StringBuffer buffer = new StringBuffer(variableText.length());
		char[] characters = variableText.toCharArray();
		for (int i = 0; i < characters.length; i++) {
			char character = characters[i];
			switch (character) {
			case '<':
				buffer.append("&lt;"); //$NON-NLS-1$
				break;
			case '>':
				buffer.append("&gt;"); //$NON-NLS-1$
				break;
			case '&':
				buffer.append("&amp;"); //$NON-NLS-1$
				break;
			case '"':
				buffer.append("&quot;"); //$NON-NLS-1$
				break;
			default:
				buffer.append(character);
			}
		}
		return buffer.toString();
	}

	/**
	 * Returns the value of this filters preference (on/off) for the given view.
	 *
	 * @param part
	 * @return boolean
	 */
	public static boolean getBooleanPreferenceValue(String id,
			String preference) {
		String compositeKey = id + "." + preference; //$NON-NLS-1$
		IPreferenceStore store = DLTKDebugUIPlugin.getDefault()
				.getPreferenceStore();
		boolean value = false;
		if (store.contains(compositeKey)) {
			value = store.getBoolean(compositeKey);
		} else {
			value = store.getBoolean(preference);
		}
		return value;
	}

	@Override
	public IInformationControlCreator getHoverControlCreator() {
		return parent -> new DefaultInformationControl(parent, SWT.NONE,
				new HTMLTextPresenter(true),
				EditorsUI.getTooltipAffordanceString());
	}

	/**
	 * Returns a configured model presentation for use displaying variables.
	 */
	protected abstract ScriptDebugModelPresentation getModelPresentation();
}