main.java

這是一個javascript 的 interpreter是了解 web browser的好材料

/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla 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/MPL/
 *
 * 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 the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. 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 General Public License Version 2 or later (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
 * MPL, indicate your decision by deleting the provisions above and replacing
 * 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 MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

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 ShellContextFactory
        shellContextFactory = new ShellContextFactory();

    public static Global global = new Global();
    static protected ToolErrorReporter errorReporter;
    static protected int exitCode = 0;
    static private final int EXITCODE_RUNTIME_ERROR = 3;
    static private final int EXITCODE_FILE_NOT_FOUND = 4;
    static boolean processStdin = true;
    static Vector fileList = new Vector(5);
    private static SecurityProxy securityImpl;

    static {
        global.initQuitAction(new IProxy(IProxy.SYSTEM_EXIT));
    }

    /**
     * Proxy class to avoid proliferation of anonymous classes.
     */
    private static class IProxy implements ContextAction, QuitAction
    {
        private static final int PROCESS_FILES = 1;
        private static final int EVAL_INLINE_SCRIPT = 2;
        private static final int SYSTEM_EXIT = 3;

        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;
        }

        public void quit(Context cx, int exitCode)
        {
            if (type == SYSTEM_EXIT) {
                System.exit(exitCode);
                return;
            }
            throw Kit.codeBug();
        }
    }

    /**
     * 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);
                errorReporter.setIsReportingWarnings(true);
                continue;
            }
            if (arg.equals("-fatal-warnings")) {
                shellContextFactory.setWarningAsError(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;
            }
            if (arg.equals("-debug")) {
                shellContextFactory.setGeneratingDebug(true);
                continue;
            }
            if (arg.equals("-?") ||
                arg.equals("-help")) {
                // print usage message
                global.getOut().println(
                    ToolErrorReporter.getMessage("msg.shell.usage", Main.class.getName()));
                System.exit(1);
            }
            usageError = arg;
            break goodUsage;
        }
        // print error and usage message
        global.getOut().println(
            ToolErrorReporter.getMessage("msg.shell.invalid", usageError));
        global.getOut().println(
            ToolErrorReporter.getMessage("msg.shell.usage", Main.class.getName()));
        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) {