tools/jjs/Main.java

/*
 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package jdk.nashorn.tools.jjs;

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import jdk.internal.jline.console.completer.Completer;
import jdk.internal.jline.console.UserInterruptException;
import jdk.nashorn.api.scripting.NashornException;
import jdk.nashorn.internal.objects.Global;
import jdk.nashorn.internal.runtime.Context;
import jdk.nashorn.internal.runtime.JSType;
import jdk.nashorn.internal.runtime.ScriptEnvironment;
import jdk.nashorn.internal.runtime.ScriptRuntime;
import jdk.nashorn.tools.Shell;

/**
 * Interactive command line Shell for Nashorn.
 */
public final class Main extends Shell {
    private Main() {}

    // file where history is persisted.
    private static final File HIST_FILE = new File(new File(System.getProperty("user.home")), ".jjs.history");

    /**
     * Main entry point with the default input, output and error streams.
     *
     * @param args The command line arguments
     */
    public static void main(final String[] args) {
        try {
            final int exitCode = main(System.in, System.out, System.err, args);
            if (exitCode != SUCCESS) {
                System.exit(exitCode);
            }
        } catch (final IOException e) {
            System.err.println(e); //bootstrapping, Context.err may not exist
            System.exit(IO_ERROR);
        }
    }

    /**
     * Starting point for executing a {@code Shell}. Starts a shell with the
     * given arguments and streams and lets it run until exit.
     *
     * @param in input stream for Shell
     * @param out output stream for Shell
     * @param err error stream for Shell
     * @param args arguments to Shell
     *
     * @return exit code
     *
     * @throws IOException if there's a problem setting up the streams
     */
    public static int main(final InputStream in, final OutputStream out, final OutputStream err, final String[] args) throws IOException {
        return new Main().run(in, out, err, args);
    }

    /**
     * read-eval-print loop for Nashorn shell.
     *
     * @param context the nashorn context
     * @param global  global scope object to use
     * @return return code
     */
    protected int readEvalPrint(final Context context, final Global global) {
        final ScriptEnvironment env = context.getEnv();
        final String prompt = bundle.getString("shell.prompt");
        final PrintWriter err = context.getErr();
        final Global oldGlobal = Context.getGlobal();
        final boolean globalChanged = (oldGlobal != global);
        final Completer completer = new NashornCompleter(context, global);

        try (final Console in = new Console(System.in, System.out, HIST_FILE, completer)) {
            if (globalChanged) {
                Context.setGlobal(global);
            }

            global.addShellBuiltins();
            // expose history object for reflecting on command line history
            global.put("history", new HistoryObject(in.getHistory()), false);

            while (true) {
                String source = "";
                try {
                    source = in.readLine(prompt);
                } catch (final IOException ioe) {
                    err.println(ioe.toString());
                    if (env._dump_on_error) {
                        ioe.printStackTrace(err);
                    }
                    return IO_ERROR;
                } catch (final UserInterruptException ex) {
                    break;
                }

                if (source.isEmpty()) {
                    continue;
                }

                try {
                    final Object res = context.eval(global, source, global, "<shell>");
                    if (res != ScriptRuntime.UNDEFINED) {
                        err.println(JSType.toString(res));
                    }
                } catch (final Exception e) {
                    err.println(e);
                    if (env._dump_on_error) {
                        e.printStackTrace(err);
                    }
                }
            }
        } catch (final Exception e) {
            err.println(e);
            if (env._dump_on_error) {
                e.printStackTrace(err);
            }
        } finally {
            if (globalChanged) {
                Context.setGlobal(oldGlobal);
            }
        }

        return SUCCESS;
    }
}