org.luaj.vm2.script.LuaScriptEngine Maven / Gradle / Ivy
Show all versions of luaj-jse Show documentation
/*******************************************************************************
* Copyright (c) 2008-2013 LuaJ. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* 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
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
******************************************************************************/
package org.luaj.vm2.script;
import java.io.*;
import javax.script.*;
import org.luaj.vm2.*;
import org.luaj.vm2.lib.ThreeArgFunction;
import org.luaj.vm2.lib.TwoArgFunction;
import org.luaj.vm2.lib.jse.CoerceJavaToLua;
/**
* Implementation of the ScriptEngine interface which can compile and execute
* scripts using luaj.
*
*
* This engine requires the types of the Bindings and ScriptContext to be
* compatible with the engine. For creating new client context use
* ScriptEngine.createContext() which will return {@link LuajContext},
* and for client bindings use the default engine scoped bindings or
* construct a {@link LuajBindings} directly.
*/
public class LuaScriptEngine extends AbstractScriptEngine implements ScriptEngine, Compilable {
private static final String __ENGINE_VERSION__ = Lua._VERSION;
private static final String __NAME__ = "Luaj";
private static final String __SHORT_NAME__ = "Luaj";
private static final String __LANGUAGE__ = "lua";
private static final String __LANGUAGE_VERSION__ = "5.2";
private static final String __ARGV__ = "arg";
private static final String __FILENAME__ = "?";
private static final ScriptEngineFactory myFactory = new LuaScriptEngineFactory();
private LuajContext context;
public LuaScriptEngine() {
// set up context
context = new LuajContext();
context.setBindings(createBindings(), ScriptContext.ENGINE_SCOPE);
setContext(context);
// set special values
put(LANGUAGE_VERSION, __LANGUAGE_VERSION__);
put(LANGUAGE, __LANGUAGE__);
put(ENGINE, __NAME__);
put(ENGINE_VERSION, __ENGINE_VERSION__);
put(ARGV, __ARGV__);
put(FILENAME, __FILENAME__);
put(NAME, __SHORT_NAME__);
put("THREADING", null);
}
@Override
public CompiledScript compile(String script) throws ScriptException {
return compile(new StringReader(script));
}
@Override
public CompiledScript compile(Reader script) throws ScriptException {
try {
InputStream is = new Utf8Encoder(script);
try {
final Globals g = context.globals;
final LuaFunction f = LoadState.load(is, "script", "bt", g);
return new LuajCompiledScript(f, g);
} catch ( LuaError lee ) {
throw new ScriptException(lee.getMessage() );
} finally {
is.close();
}
} catch ( Exception e ) {
throw new ScriptException("eval threw "+e.toString());
}
}
@Override
public Bindings createBindings() {
return new SimpleBindings();
}
@Override
public Object eval(String script, ScriptContext context)
throws ScriptException {
return eval(new StringReader(script), context);
}
@Override
public Object eval(Reader reader, ScriptContext context)
throws ScriptException {
return compile(reader).eval();
}
@Override
public ScriptEngineFactory getFactory() {
return myFactory;
}
class LuajCompiledScript extends CompiledScript {
final LuaFunction function;
final Globals compiling_globals;
LuajCompiledScript(LuaFunction function, Globals compiling_globals) {
this.function = function;
this.compiling_globals = compiling_globals;
}
public ScriptEngine getEngine() {
return LuaScriptEngine.this;
}
public Object eval() throws ScriptException {
return eval(getContext());
}
public Object eval(Bindings bindings) throws ScriptException {
return eval(((LuajContext) getContext()).globals, bindings);
}
public Object eval(ScriptContext context) throws ScriptException {
return eval(((LuajContext) context).globals, context.getBindings(ScriptContext.ENGINE_SCOPE));
}
private Object eval(Globals g, Bindings b) throws ScriptException {
g.setmetatable(new BindingsMetatable(b));
LuaFunction f = function;
if (f.isclosure())
f = new LuaClosure(f.checkclosure().p, g);
else {
try {
f = f.getClass().newInstance();
} catch (Exception e) {
throw new ScriptException(e);
}
f.initupvalue1(g);
}
return toJava(f.invoke(LuaValue.NONE));
}
}
// ------ convert char stream to byte stream for lua compiler -----
private final class Utf8Encoder extends InputStream {
private final Reader r;
private final int[] buf = new int[2];
private int n;
private Utf8Encoder(Reader r) {
this.r = r;
}
public int read() throws IOException {
if ( n > 0 )
return buf[--n];
int c = r.read();
if ( c < 0x80 )
return c;
n = 0;
if ( c < 0x800 ) {
buf[n++] = (0x80 | ( c & 0x3f));
return (0xC0 | ((c>>6) & 0x1f));
} else {
buf[n++] = (0x80 | ( c & 0x3f));
buf[n++] = (0x80 | ((c>>6) & 0x3f));
return (0xE0 | ((c>>12) & 0x0f));
}
}
}
static class BindingsMetatable extends LuaTable {
BindingsMetatable(final Bindings bindings) {
this.rawset(LuaValue.INDEX, new TwoArgFunction() {
public LuaValue call(LuaValue table, LuaValue key) {
if (key.isstring())
return toLua(bindings.get(key.tojstring()));
else
return this.rawget(key);
}
});
this.rawset(LuaValue.NEWINDEX, new ThreeArgFunction() {
public LuaValue call(LuaValue table, LuaValue key, LuaValue value) {
if (key.isstring()) {
final String k = key.tojstring();
final Object v = toJava(value);
if (v == null)
bindings.remove(k);
else
bindings.put(k, v);
} else {
this.rawset(key, value);
}
return LuaValue.NONE;
}
});
}
}
static private LuaValue toLua(Object javaValue) {
return javaValue == null? LuaValue.NIL:
javaValue instanceof LuaValue? (LuaValue) javaValue:
CoerceJavaToLua.coerce(javaValue);
}
static private Object toJava(LuaValue luajValue) {
switch ( luajValue.type() ) {
case LuaValue.TNIL: return null;
case LuaValue.TSTRING: return luajValue.tojstring();
case LuaValue.TUSERDATA: return luajValue.checkuserdata(Object.class);
case LuaValue.TNUMBER: return luajValue.isinttype()?
(Object) new Integer(luajValue.toint()):
(Object) new Double(luajValue.todouble());
default: return luajValue;
}
}
static private Object toJava(Varargs v) {
final int n = v.narg();
switch (n) {
case 0: return null;
case 1: return toJava(v.arg1());
default:
Object[] o = new Object[n];
for (int i=0; i