main.java

javascript语言的解释器源码

/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1998.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1997-1999 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s):
 * Patrick Beard
 * Norris Boyd
 * Igor Bukanov
 * Rob Ginda
 * Kurt Westerfeld
 *
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU Public License (the "GPL"), in which case the
 * provisions of the GPL are applicable instead of those above.
 * If you wish to allow use of your version of this file only
 * under the terms of the GPL and not to allow others to use your
 * version of this file under the NPL, indicate your decision by
 * deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL.  If you do not delete
 * the provisions above, a recipient may use your version of this
 * file under either the NPL or the GPL.
 */

package org.mozilla.javascript.tools.shell;

import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.net.MalformedURLException;
import java.util.*;
import org.mozilla.javascript.*;
import org.mozilla.javascript.tools.ToolErrorReporter;

/**
 * The shell program.
 *
 * Can execute scripts interactively or in batch mode at the command line.
 * An example of controlling the JavaScript engine.
 *
 * @author Norris Boyd
 */
public class Main
{
    public static final ShellContextFactory
        shellContextFactory = new ShellContextFactory();

    /**
     * Proxy class to avoid proliferation of anonymous classes.
     */
    private static class IProxy implements ContextAction
    {
        private static final int PROCESS_FILES = 1;
        private static final int EVAL_INLINE_SCRIPT = 2;

        private int type;
        String[] args;
        String scriptText;

        IProxy(int type)
        {
            this.type = type;
        }

        public Object run(Context cx)
        {
            if (type == PROCESS_FILES) {
                processFiles(cx, args);
            } else if (type == EVAL_INLINE_SCRIPT) {
                Script script = loadScriptFromSource(cx, scriptText,
                                                     "<command>", 1, null);
                if (script != null) {
                    evaluateScript(script, cx, getGlobal());
                }
            } else {
                throw Kit.codeBug();
            }
            return null;
        }
    }

    /**
     * Main entry point.
     *
     * Process arguments as would a normal Java program. Also
     * create a new Context and associate it with the current thread.
     * Then set up the execution environment and begin to
     * execute scripts.
     */
    public static void main(String args[]) {
        try {
            if (Boolean.getBoolean("rhino.use_java_policy_security")) {
                initJavaPolicySecuritySupport();
            }
        } catch (SecurityException ex) {
            ex.printStackTrace(System.err);
        }

        int result = exec(args);
        if (result != 0) {
            System.exit(result);
        }
    }

    /**
     *  Execute the given arguments, but don't System.exit at the end.
     */
    public static int exec(String origArgs[])
    {
        errorReporter = new ToolErrorReporter(false, global.getErr());
        shellContextFactory.setErrorReporter(errorReporter);
        String[] args = processOptions(origArgs);
        if (processStdin)
            fileList.addElement(null);

        if (!global.initialized) {
            global.init(shellContextFactory);
        }
        IProxy iproxy = new IProxy(IProxy.PROCESS_FILES);
        iproxy.args = args;
        shellContextFactory.call(iproxy);

        return exitCode;
    }

    static void processFiles(Context cx, String[] args)
    {
        // define "arguments" array in the top-level object:
        // need to allocate new array since newArray requires instances
        // of exactly Object[], not ObjectSubclass[]
        Object[] array = new Object[args.length];
        System.arraycopy(args, 0, array, 0, args.length);
        Scriptable argsObj = cx.newArray(global, array);
        global.defineProperty("arguments", argsObj,
                              ScriptableObject.DONTENUM);

        for (int i=0; i < fileList.size(); i++) {
            processSource(cx, (String) fileList.elementAt(i));
        }

    }

    public static Global getGlobal()
    {
        return global;
    }

    /**
     * Parse arguments.
     */
    public static String[] processOptions(String args[])
    {
        String usageError;
        goodUsage: for (int i = 0; ; ++i) {
            if (i == args.length) {
                return new String[0];
            }
            String arg = args[i];
            if (!arg.startsWith("-")) {
                processStdin = false;
                fileList.addElement(arg);
                String[] result = new String[args.length - i - 1];
                System.arraycopy(args, i+1, result, 0, args.length - i - 1);
                return result;
            }
            if (arg.equals("-version")) {
                if (++i == args.length) {
                    usageError = arg;
                    break goodUsage;
                }
                int version;
                try {
                    version = Integer.parseInt(args[i]);
                } catch (NumberFormatException ex) {
                    usageError = args[i];
                    break goodUsage;
                }
                if (!Context.isValidLanguageVersion(version)) {
                    usageError = args[i];
                    break goodUsage;
                }
                shellContextFactory.setLanguageVersion(version);
                continue;
            }
            if (arg.equals("-opt") || arg.equals("-O")) {
                if (++i == args.length) {
                    usageError = arg;
                    break goodUsage;
                }
                int opt;
                try {
                    opt = Integer.parseInt(args[i]);
                } catch (NumberFormatException ex) {
                    usageError = args[i];
                    break goodUsage;
                }
                if (opt == -2) {
                    // Compatibility with Cocoon Rhino fork
                    opt = -1;
                } else if (!Context.isValidOptimizationLevel(opt)) {
                    usageError = args[i];
                    break goodUsage;
                }
                shellContextFactory.setOptimizationLevel(opt);
                continue;
            }
            if (arg.equals("-strict")) {
                shellContextFactory.setStrictMode(true);
                continue;
            }
            if (arg.equals("-e")) {
                processStdin = false;
                if (++i == args.length) {
                    usageError = arg;
                    break goodUsage;
                }
                if (!global.initialized) {
                    global.init(shellContextFactory);
                }
                IProxy iproxy = new IProxy(IProxy.EVAL_INLINE_SCRIPT);
                iproxy.scriptText = args[i];
                shellContextFactory.call(iproxy);
                continue;
            }
            if (arg.equals("-w")) {
                errorReporter.setIsReportingWarnings(true);
                continue;
            }
            if (arg.equals("-f")) {
                processStdin = false;
                if (++i == args.length) {
                    usageError = arg;
                    break goodUsage;
                }
                fileList.addElement(args[i].equals("-") ? null : args[i]);
                continue;
            }
            if (arg.equals("-sealedlib")) {
                global.setSealedStdLib(true);
                continue;
            }
            usageError = arg;
            break goodUsage;
        }
        // print usage message
        global.getOut().println(
            ToolErrorReporter.getMessage("msg.shell.usage", usageError));
        System.exit(1);
        return null;
    }

    private static void initJavaPolicySecuritySupport()
    {
        Throwable exObj;
        try {
            Class cl = Class.forName
                ("org.mozilla.javascript.tools.shell.JavaPolicySecurity");
            securityImpl = (SecurityProxy)cl.newInstance();
            SecurityController.initGlobal(securityImpl);
            return;
        } catch (ClassNotFoundException ex) {
            exObj = ex;
        } catch (IllegalAccessException ex) {
            exObj = ex;
        } catch (InstantiationException ex) {
            exObj = ex;
        } catch (LinkageError ex) {
            exObj = ex;
        }
        throw Kit.initCause(new IllegalStateException(
            "Can not load security support: "+exObj), exObj);
    }

    /**
     * Evaluate JavaScript source.
     *
     * @param cx the current context
     * @param filename the name of the file to compile, or null
     *                 for interactive mode.
     */
    public static void processSource(Context cx, String filename)
    {
        if (filename == null || filename.equals("-")) {
            PrintStream ps = global.getErr();