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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.utils;

import java.io.*;
import java.util.*;

/**
 * Utility class for finding resources for a class.
 *
 * <p>
 * Same as {@link ClasspathResourceFinderSimple}, but first searches the working directory for the file before
 * looking in the classpath.
 * <br>Path traversals outside the working directory are not allowed for security reasons.
 */
public class ClasspathResourceFinderBasic extends ClasspathResourceFinderSimple {

	/**
	 * Reusable instance.
	 */
	public static final ClasspathResourceFinderBasic INSTANCE = new ClasspathResourceFinderBasic();

	@Override /* ClasspathResourceFinder */
	public InputStream findResource(Class<?> baseClass, String name, Locale locale) throws IOException {
		InputStream is = findFileSystemResource(name, locale);
		if (is != null)
			return is;
		return findClasspathResource(baseClass, name, locale);
	}

	/**
	 * Workhorse method for retrieving a resource from the file system.
	 *
	 * <p>
	 * This method can be overridden by subclasses to provide customized handling of resource retrieval from file systems.
	 *
	 * @param name The resource name.
	 * @param locale
	 * 	The resource locale.
	 * 	<br>Can be <jk>null</jk>.
	 * @return The resource stream, or <jk>null</jk> if it couldn't be found.
	 * @throws IOException Thrown by underlying stream.
	 */
	protected InputStream findFileSystemResource(String name, Locale locale) throws IOException {
		if (name.indexOf("..") == -1) {
			for (String n2 : getCandidateFileNames(name, locale)) {
				File f = new File(n2);
				if (f.exists() && f.canRead() && ! f.isAbsolute()) {
					return new FileInputStream(f);
				}
			}
		}
		return null;
	}
}