public static String getRelativeFilePath()

in src/main/java/org/apache/maven/shared/utils/PathTool.java [131:179]
32 lines of code
16 McCabe index (conditional complexity)

    public static String getRelativeFilePath(final String oldPath, final String newPath) {
        if (StringUtils.isEmpty(oldPath) || StringUtils.isEmpty(newPath)) {
            return "";
        }

        // normalise the path delimiters
        String fromPath = new File(oldPath).getPath();
        String toPath = new File(newPath).getPath();

        // strip any leading slashes if its a windows path
        if (toPath.matches("^\\[a-zA-Z]:")) {
            toPath = toPath.substring(1);
        }
        if (fromPath.matches("^\\[a-zA-Z]:")) {
            fromPath = fromPath.substring(1);
        }

        // lowercase windows drive letters.
        if (fromPath.startsWith(":", 1)) {
            fromPath = Character.toLowerCase(fromPath.charAt(0)) + fromPath.substring(1);
        }
        if (toPath.startsWith(":", 1)) {
            toPath = Character.toLowerCase(toPath.charAt(0)) + toPath.substring(1);
        }

        // check for the presence of windows drives. No relative way of
        // traversing from one to the other.
        if ((toPath.startsWith(":", 1) && fromPath.startsWith(":", 1))
                && (!toPath.substring(0, 1).equals(fromPath.substring(0, 1)))) {
            // they both have drive path element but they dont match, no
            // relative path
            return null;
        }

        if ((toPath.startsWith(":", 1) && !fromPath.startsWith(":", 1))
                || (!toPath.startsWith(":", 1) && fromPath.startsWith(":", 1))) {
            // one has a drive path element and the other doesnt, no relative
            // path.
            return null;
        }

        String resultPath = buildRelativePath(toPath, fromPath, File.separatorChar);

        if (newPath.endsWith(File.separator) && !resultPath.endsWith(File.separator)) {
            return resultPath + File.separator;
        }

        return resultPath;
    }