core/plugins/org.eclipse.dltk.ui/src/org/eclipse/dltk/internal/ui/text/ScriptElementProvider.java

/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation and others.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 * 
 * SPDX-License-Identifier: EPL-2.0
 *
 *******************************************************************************/
package org.eclipse.dltk.internal.ui.text;

import org.eclipse.dltk.core.IModelElement;
import org.eclipse.dltk.core.ModelException;
import org.eclipse.dltk.internal.ui.actions.SelectionConverter;
import org.eclipse.dltk.internal.ui.editor.EditorUtility;
import org.eclipse.dltk.internal.ui.editor.ScriptEditor;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.information.IInformationProvider;
import org.eclipse.jface.text.information.IInformationProviderExtension;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IEditorPart;

/**
 * Provides a Script element to be displayed in by an information presenter.
 */
public class ScriptElementProvider
		implements IInformationProvider, IInformationProviderExtension {

	private ScriptEditor fEditor;
	private boolean fUseCodeResolve;

	public ScriptElementProvider(IEditorPart editor) {
		fUseCodeResolve = false;
		if (editor instanceof ScriptEditor)
			fEditor = (ScriptEditor) editor;
	}

	public ScriptElementProvider(IEditorPart editor, boolean useCodeResolve) {
		this(editor);
		fUseCodeResolve = useCodeResolve;
	}

	@Override
	public IRegion getSubject(ITextViewer textViewer, int offset) {
		if (textViewer != null && fEditor != null) {
			IRegion region = ScriptWordFinder.findWord(textViewer.getDocument(),
					offset);
			if (region != null) {
				return region;
			}
			return new Region(offset, 0);
		}
		return null;
	}

	@Override
	public String getInformation(ITextViewer textViewer, IRegion subject) {
		return getInformation2(textViewer, subject).toString();
	}

	@Override
	public Object getInformation2(ITextViewer textViewer, IRegion subject) {
		if (fEditor == null)
			return null;

		try {
			if (fUseCodeResolve) {
				IStructuredSelection sel = SelectionConverter
						.getStructuredSelection(fEditor);
				if (!sel.isEmpty())
					return sel.getFirstElement();
			}
			IModelElement element = SelectionConverter
					.getElementAtOffset(fEditor);
			if (element != null)
				return element;

			return EditorUtility.getEditorInputModelElement(fEditor, false);
		} catch (ModelException e) {
			return null;
		}
	}
}