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/*******************************************************************************
* Copyright (c) 2009 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
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* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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package org.luaj.vm2.lib.jse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import org.luaj.vm2.LuaValue;
import org.luaj.vm2.lib.BaseLib;
import org.luaj.vm2.lib.LibFunction;
import org.luaj.vm2.lib.ResourceFinder;
/**
* Subclass of {@link BaseLib} and {@link LibFunction} which implements the lua basic library functions
* and provides a directory based {@link ResourceFinder} as the {@link #FINDER}.
*
* Since JME has no file system by default, {@link BaseLib} implements
* {@link ResourceFinder} using {@link Class#getResource(String)}.
* The {@link JseBaseLib} implements {@link FINDER} by scanning the current directory
* first, then falling back to {@link Class#getResource(String)} if that fails.
* Otherwise, the behavior is the same as that of {@link BaseLib}.
*
* Typically, this library is included as part of a call to
* {@link JsePlatform#standardGlobals()}
*
{@code
* Globals globals = JsePlatform.standardGlobals();
* globals.get("print").call(LuaValue.valueOf("hello, world"));
* }
*
* For special cases where the smallest possible footprint is desired,
* a minimal set of libraries could be loaded
* directly via {@link Globals#load(LuaValue)} using code such as:
*
{@code
* Globals globals = new Globals();
* globals.load(new JseBaseLib());
* globals.get("print").call(LuaValue.valueOf("hello, world"));
* }
* However, other libraries such as PackageLib are not loaded in this case.
*
* This is a direct port of the corresponding library in C.
* @see Globals
* @see BaseLib
* @see ResourceFinder
* @see {@link Globals.FINDER}
* @see LibFunction
* @see JsePlatform
* @see org.luaj.vm2.lib.jme.JmePlatform
* @see Lua 5.2 Base Lib Reference
*/
public class JseBaseLib extends org.luaj.vm2.lib.BaseLib {
/** Extend the library loading to set the default value for {@link Globals.STDIN} */
public LuaValue call(LuaValue modname, LuaValue env) {
super.call(modname, env);
env.checkglobals().STDIN = System.in;
return env;
}
/**
* Try to open a file in the current working directory,
* or fall back to base opener if not found.
*
* This implementation attempts to open the file using new File(filename).
* It falls back to the base implementation that looks it up as a resource
* in the class path if not found as a plain file.
*
* @see org.luaj.vm2.lib.BaseLib
* @see org.luaj.vm2.lib.ResourceFinder
*
* @param filename
* @return InputStream, or null if not found.
*/
public InputStream findResource(String filename) {
File f = new File(filename);
if ( ! f.exists() )
return super.findResource(filename);
try {
return new FileInputStream(f);
} catch ( IOException ioe ) {
return null;
}
}
}