SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// Multi-Phasic Applications: SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.runtime.cldc.full;

import cc.squirreljme.jvm.mle.RuntimeShelf;
import java.nio.file.Path;
import java.nio.file.Paths;

/**
 * Provides Unix Paths.
 *
 * @since 2024/02/25
 */
public class UnixPathProvider
    extends SystemPathProvider
{
    /**
     * {@inheritDoc}
     * @since 2024/02/25
     */
    @Override
    public Path cache()
    {
        Path path = UnixPathProvider.__env("XDG_CACHE_HOME",
            ".cache");
        if (path != null)
            return path.resolve("squirreljme");
        
        return null;
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/02/25
     */
    @Override
    public Path config()
    {
        Path path = UnixPathProvider.__env("XDG_CONFIG_HOME",
            ".config");
        if (path != null)
            return path.resolve("squirreljme");
        
        return null;
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/02/25
     */
    @Override
    public Path data()
    {
        Path path = UnixPathProvider.__env("XDG_DATA_HOME",
            ".local/share");
        if (path != null)
            return path.resolve("squirreljme");
        
        return null;
    }
    
    /**
     * {@inheritDoc}
     * @since 2024/02/25
     */
    @Override
    public Path state()
    {
        Path path = UnixPathProvider.__env("XDG_STATE_HOME",
            ".local/state");
        if (path != null)
            return path.resolve("squirreljme");
        
        return null;
    }
    
    /**
     * Returns a value from the environment variable or the default.
     *
     * @param __var The variable to check.
     * @param __fromHome The path from the home directory.
     * @return The resultant path or {@code null} if there is none.
     * @throws NullPointerException On null arguments.
     * @since 2024/02/25
     */
    private static Path __env(String __var, String __fromHome)
        throws NullPointerException
    {
        if (__var == null || __fromHome == null)
            throw new NullPointerException("NARG");
        
        // From variable
        String xdg = RuntimeShelf.systemEnv(__var);
        if (xdg != null)
            return Paths.get(xdg);
        
        // Home directory
        String homeDir = RuntimeShelf.systemEnv("HOME");
        if (homeDir != null)
            return Paths.get(homeDir).resolve(__fromHome);
        
        return null;
    }
}