ReturnStatementReplacer.java

/***** BEGIN LICENSE BLOCK *****
 * Version: CPL 1.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Common Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/cpl-v10.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2006 Mirko Stocker <me@misto.ch>
 * 
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 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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package org.rubypeople.rdt.refactoring.core.inlinemethod;

import org.jruby.ast.AssignableNode;
import org.jruby.ast.Node;
import org.jruby.ast.ReturnNode;
import org.rubypeople.rdt.core.formatter.ReWriteVisitor;
import org.rubypeople.rdt.refactoring.core.NodeProvider;
import org.rubypeople.rdt.refactoring.documentprovider.DocumentProvider;
import org.rubypeople.rdt.refactoring.documentprovider.StringDocumentProvider;
import org.rubypeople.rdt.refactoring.util.FileHelper;

public class ReturnStatementReplacer implements IReturnStatementReplacer {

	public boolean singleReturnOnLastLine(DocumentProvider doc) {

		if(countReturnNodes(doc) > 1) {
			return false;
		} else if (countReturnNodes(doc) == 1) {
			return returnIsOnLastLine(getReturnNode(doc), doc);
		} else {
			return true;
		}
	}
	
	private boolean returnIsOnLastLine(ReturnNode node, DocumentProvider doc) {
		// FIXME Trim whitespace off the end of the active file content!
		String[] lines = doc.getActiveFileContent().split("(\\r)?\\n");
		return node.getPosition().getStartLine() == lines.length; //$NON-NLS-1$
	}

	private int countReturnNodes(DocumentProvider doc) {
		int returnNodes = 0;
		for (Node node : NodeProvider.getAllNodes(doc.getActiveFileRootNode())) {
			if(node instanceof ReturnNode) {
				returnNodes++;
			}
		}
		return returnNodes;
	}

	private ReturnNode getReturnNode(DocumentProvider doc) {
		for (Node node : NodeProvider.getAllNodes(doc.getActiveFileRootNode())) {
			if(node instanceof ReturnNode) {
				return (ReturnNode) node;
			}
		}
		return null;
	}
	

	public DocumentProvider replaceReturn(DocumentProvider doc, AssignableNode target) {
		
 		if(!singleReturnOnLastLine(doc) || target == null) {
			return null;
		}
		
		StringBuilder result = new StringBuilder();
		ReturnNode returnNode = getReturnNode(doc);
		
		if(returnNode == null) {
			insertLastLineToAssignment(doc, target, result);
		} else {
			replaceReturnStatementWithAssignment(doc, target, result, returnNode);
		}

		return new StringDocumentProvider("part_of_" + doc.getActiveFileName(), result.append(ReWriteVisitor.createCodeFromNode(target, doc.getActiveFileContent())).toString()); //$NON-NLS-1$
		
	}

	private void insertLastLineToAssignment(DocumentProvider doc, AssignableNode target, StringBuilder result) {
		String[] lines = doc.getActiveFileContent().split("(\\r)?\\n"); //$NON-NLS-1$
		target.setValueNode(NodeProvider.getRootNode("last_line_of_" + doc.getActiveFileName() + "_for_ReturnStatementReplacer", lines[lines.length - 1]).getBodyNode()); //$NON-NLS-1$ //$NON-NLS-2$
		String lineDelimiter = FileHelper.getLineDelimiter(doc.getActiveFileContent());
		
		for(int i = 0; i < lines.length - 1; i++) {
			result.append(lines[i]);
			result.append(lineDelimiter);
		}
	}

	private void replaceReturnStatementWithAssignment(DocumentProvider doc, AssignableNode target, StringBuilder result, ReturnNode returnNode) {
		target.setValueNode(returnNode.getValueNode());
		result.append(doc.getActiveFileContent().substring(0, returnNode.getPosition().getStartOffset()));
	}
}