content: /*******************************************************************************
   * Copyright (c) 2000, 2008 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.internal.ui.javaeditor.selectionactions;
  
  import java.util.List;
  
  import org.eclipse.core.runtime.Assert;
  import org.eclipse.jface.action.Action;
  import org.eclipse.jface.dialogs.MessageDialog;
  import org.eclipse.jface.text.ITextSelection;
  import org.eclipse.wst.jsdt.core.IJavaScriptElement;
  import org.eclipse.wst.jsdt.core.ISourceRange;
  import org.eclipse.wst.jsdt.core.ISourceReference;
  import org.eclipse.wst.jsdt.core.JavaScriptModelException;
  import org.eclipse.wst.jsdt.core.dom.ASTNode;
  import org.eclipse.wst.jsdt.core.dom.JavaScriptUnit;
  import org.eclipse.wst.jsdt.core.dom.StructuralPropertyDescriptor;
  import org.eclipse.wst.jsdt.internal.corext.SourceRange;
  import org.eclipse.wst.jsdt.internal.corext.dom.Selection;
  import org.eclipse.wst.jsdt.internal.corext.dom.SelectionAnalyzer;
  import org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin;
  import org.eclipse.wst.jsdt.internal.ui.javaeditor.ASTProvider;
  import org.eclipse.wst.jsdt.internal.ui.javaeditor.EditorUtility;
  import org.eclipse.wst.jsdt.internal.ui.javaeditor.JavaEditor;
  
  public abstract class StructureSelectionAction extends Action {
  
  	public static final String NEXT= "SelectNextElement"; //$NON-NLS-1$
  	public static final String PREVIOUS= "SelectPreviousElement"; //$NON-NLS-1$
  	public static final String ENCLOSING= "SelectEnclosingElement"; //$NON-NLS-1$
  	public static final String HISTORY= "RestoreLastSelection"; //$NON-NLS-1$
  
  	private JavaEditor fEditor;
  	private SelectionHistory fSelectionHistory;
  
  	protected StructureSelectionAction(String text, JavaEditor editor, SelectionHistory history) {
  		super(text);
  		Assert.isNotNull(editor);
  		Assert.isNotNull(history);
  		fEditor= editor;
  		fSelectionHistory= history;
  	}
  
  	/*
  	 * This constructor is for testing purpose only.
  	 */
  	protected StructureSelectionAction() {
  		super(""); //$NON-NLS-1$
  	}
  
  	/*
  	 * Method declared in IAction.
  	 */
  	public final  void run() {
  		IJavaScriptElement inputElement= EditorUtility.getEditorInputJavaElement(fEditor, false);
  		if (!(inputElement instanceof ISourceReference && inputElement.exists()))
  			return;
  
  		ISourceReference source= (ISourceReference)inputElement;
  		ISourceRange sourceRange;
  		try {
  			sourceRange= source.getSourceRange();
  			if (sourceRange == null || sourceRange.getLength() == 0) {
  				MessageDialog.openInformation(fEditor.getEditorSite().getShell(),
  					SelectionActionMessages.StructureSelect_error_title,
  					SelectionActionMessages.StructureSelect_error_message);
  				return;
  			}
  		} catch (JavaScriptModelException e) {
  		}
  		ITextSelection selection= getTextSelection();
  		ISourceRange newRange= getNewSelectionRange(createSourceRange(selection), source);
  		// Check if new selection differs from current selection
  		if (selection.getOffset() == newRange.getOffset() && selection.getLength() == newRange.getLength())
  			return;
  		fSelectionHistory.remember(new SourceRange(selection.getOffset(), selection.getLength()));
  		try {
  			fSelectionHistory.ignoreSelectionChanges();
  			fEditor.selectAndReveal(newRange.getOffset(), newRange.getLength());
  		} finally {
  			fSelectionHistory.listenToSelectionChanges();
  		}
  	}
  
  	public final ISourceRange getNewSelectionRange(ISourceRange oldSourceRange, ISourceReference sr) {
  		try{
  			JavaScriptUnit root= getAST(sr);
  			if (root == null)
  				return oldSourceRange;
  			Selection selection= Selection.createFromStartLength(oldSourceRange.getOffset(), oldSourceRange.getLength());
  			SelectionAnalyzer selAnalyzer= new SelectionAnalyzer(selection, true);
  			root.accept(selAnalyzer);
  			return internalGetNewSelectionRange(oldSourceRange, sr, selAnalyzer);
  	 	}	catch (JavaScriptModelException e){
  	 		JavaScriptPlugin.log(e); //dialog would be too heavy here
  	 		return new SourceRange(oldSourceRange.getOffset(), oldSourceRange.getLength());
  	 	}
  	}
  
  	/**
  	 * Subclasses determine the actual new selection.
  	 */
  	abstract ISourceRange internalGetNewSelectionRange(ISourceRange oldSourceRange, ISourceReference sr, SelectionAnalyzer selAnalyzer) throws JavaScriptModelException;
  
  	protected final ITextSelection getTextSelection() {
  		return (ITextSelection)fEditor.getSelectionProvider().getSelection();
  	}
  	
  	// -- helper methods for subclasses to fit a node range into the source range
  
  	protected static ISourceRange getLastCoveringNodeRange(ISourceRange oldSourceRange, ISourceReference sr, SelectionAnalyzer selAnalyzer) throws JavaScriptModelException {
  		if (selAnalyzer.getLastCoveringNode() == null)
  			return oldSourceRange;
  		else
  			return getSelectedNodeSourceRange(sr, selAnalyzer.getLastCoveringNode());
  	}
  
  	protected static ISourceRange getSelectedNodeSourceRange(ISourceReference sr, ASTNode nodeToSelect) throws JavaScriptModelException {
  		int offset= nodeToSelect.getStartPosition();
  		int end= Math.min(sr.getSourceRange().getLength(), nodeToSelect.getStartPosition() + nodeToSelect.getLength() - 1);
  		return createSourceRange(offset, end);
  	}
  
  	//-- private helper methods
  
  	private static ISourceRange createSourceRange(ITextSelection ts){
  		return new SourceRange(ts.getOffset(), ts.getLength());
  	}
  
  	private static JavaScriptUnit getAST(ISourceReference sr) {
  		return ASTProvider.getASTProvider().getAST((IJavaScriptElement) sr, ASTProvider.WAIT_YES, null);
  	}
  
  	//-- helper methods for this class and subclasses
  
  	static ISourceRange createSourceRange(int offset, int end){
  		int length= end - offset + 1;
  		if (length == 0) //to allow 0-length selection
  			length= 1;
  		return new SourceRange(Math.max(0, offset), length);
  	}
  
  	static ASTNode[] getSiblingNodes(ASTNode node) {
  		ASTNode parent= node.getParent();
  		StructuralPropertyDescriptor locationInParent= node.getLocationInParent();
  		if (locationInParent.isChildListProperty()) {
  			List siblings= (List) parent.getStructuralProperty(locationInParent);
  			return (ASTNode[]) siblings.toArray(new ASTNode[siblings.size()]);
  		}
  		return null;
  	}
  
  	static int findIndex(Object[] array, Object o){
  		for (int i= 0; i < array.length; i++) {
  			Object object= array[i];
  			if (object == o)
  				return i;
  		}
  		return -1;
  	}
  
  }
  