org.cloudsmith.geppetto.ruby.jrubyparser.JRubyparserUtils.java Source code

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Here is the source code for org.cloudsmith.geppetto.ruby.jrubyparser.JRubyparserUtils.java

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/**
 * Copyright (c) 2012 Cloudsmith Inc. and other contributors, as listed below.
 * 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:
 *   Cloudsmith
 * 
 */
package org.cloudsmith.geppetto.ruby.jrubyparser;

import java.io.File;
import java.io.IOException;

import org.jrubyparser.SourcePosition;
import org.jrubyparser.ast.Node;

import com.google.common.base.Charsets;
import com.google.common.io.Files;

/**
 * Utils for JRubyparser
 * 
 */
public class JRubyparserUtils {

    /**
     * Finds position on line for a node.
     * This is a very expensive operation as it needs to open the file, read it and scan!
     * 
     * @param n
     * @return
     */
    public static int posOnLine(Node n) {
        SourcePosition p = n.getPosition();
        String s = rootContent(n);
        if (s == null)
            return -1;
        for (int i = p.getStartOffset(); i > 0; i--)
            if (s.charAt(i) == '\n')
                return p.getStartOffset() - i - 1;
        return p.getStartOffset(); // it was on the firstline.
    }

    /**
     * Reads the root content of the Node's source file and returns it as a string.
     * Returns null on failure to read the content.
     * 
     * @param n
     * @return
     */
    public static String rootContent(Node n) {
        SourcePosition p = n.getPosition();
        File f = new File(p.getFile());
        try {
            return Files.toString(f, Charsets.UTF_8);
        } catch (IOException e) {
            return null;
        }

    }
}