/*

 * Copyright (c) 2015, 2019, 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.

 *

 * 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 org.graalvm.compiler.hotspot;

import static org.graalvm.compiler.hotspot.HotSpotGraalOptionValues.GRAAL_OPTION_PROPERTY_PREFIX;

import static org.graalvm.compiler.hotspot.HotSpotGraalOptionValues.defaultOptions;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.io.PrintStream;

import java.util.List;

import org.graalvm.compiler.core.common.SuppressFBWarnings;

import org.graalvm.compiler.debug.TTYStreamProvider;

import org.graalvm.compiler.options.Option;

import org.graalvm.compiler.options.OptionKey;

import org.graalvm.compiler.options.OptionType;

import org.graalvm.compiler.serviceprovider.GraalServices;

import org.graalvm.compiler.serviceprovider.ServiceProvider;

import jdk.vm.ci.common.NativeImageReinitialize;

import jdk.vm.ci.hotspot.HotSpotJVMCIRuntime;

import jdk.vm.ci.services.Services;

@ServiceProvider(TTYStreamProvider.class)

public class HotSpotTTYStreamProvider implements TTYStreamProvider {

    public static class Options {

        // @formatter:off

        @Option(help = "File to which logging is sent.  A %p in the name will be replaced with a string identifying " +

                       "the process, usually the process id and %t will be replaced by System.currentTimeMillis().  " +

                       "Using %o as filename sends logging to System.out whereas %e sends logging to System.err.", type = OptionType.Expert)

        public static final LogStreamOptionKey LogFile = new LogStreamOptionKey();

        // @formatter:on

    }

    @Override

    public PrintStream getStream() {

        return Options.LogFile.getStream();

    }

    /**

     * An option for a configurable file name that can also open a {@link PrintStream} on the file.

     * If no value is given for the option, the stream will output to HotSpot's

     * {@link HotSpotJVMCIRuntime#getLogStream() log} stream

     */

    private static class LogStreamOptionKey extends OptionKey<String> {

        LogStreamOptionKey() {

            super(null);

        }

        /**

         * @return {@code nameTemplate} with all instances of %p replaced by

         *         {@link GraalServices#getExecutionID()} and %t by

         *         {@link System#currentTimeMillis()}. Checks %o and %e are not combined with any

         *         other characters.

         */

        private static String makeFilename(String nameTemplate) {

            String name = nameTemplate;

            if (name.contains("%p")) {

                name = name.replaceAll("%p", GraalServices.getExecutionID());

            }

            if (name.contains("%t")) {

                name = name.replaceAll("%t", String.valueOf(System.currentTimeMillis()));

            }

            for (String subst : new String[]{"%o", "%e"}) {

                if (name.contains(subst) && !name.equals(subst)) {

                    throw new IllegalArgumentException("LogFile substitution " + subst + " cannot be combined with any other characters");

                }

            }

            return name;

        }

        /**

         * An output stream that redirects to {@link HotSpotJVMCIRuntime#getLogStream()}. The

         * {@link HotSpotJVMCIRuntime#getLogStream()} value is only accessed the first time an IO

         * operation is performed on the stream. This is required to break a deadlock in early JVMCI

         * initialization.

         */

        class DelayedOutputStream extends OutputStream {

            @NativeImageReinitialize private volatile OutputStream lazy;

            private OutputStream lazy() {

                if (lazy == null) {

                    synchronized (this) {

                        if (lazy == null) {

                            String nameTemplate = LogStreamOptionKey.this.getValue(defaultOptions());

                            if (nameTemplate != null) {

                                String name = makeFilename(nameTemplate);

                                switch (name) {

                                    case "%o":

                                        lazy = System.out;

                                        break;

                                    case "%e":

                                        lazy = System.err;

                                        break;

                                    default:

                                        try {

                                            final boolean enableAutoflush = true;

                                            FileOutputStream result = new FileOutputStream(name);

                                            if (!Services.IS_IN_NATIVE_IMAGE) {

                                                printVMConfig(enableAutoflush, result);

                                            } else {

                                                // There are no VM arguments for the libgraal

                                                // library.

                                            }

                                            lazy = result;

                                        } catch (FileNotFoundException e) {

                                            throw new RuntimeException("couldn't open file: " + name, e);

                                        }

                                }

                                return lazy;

                            }

                            lazy = HotSpotJVMCIRuntime.runtime().getLogStream();

                            PrintStream ps = new PrintStream(lazy);

                            ps.printf("[Use -D%sLogFile=<path> to redirect Graal log output to a file.]%n", GRAAL_OPTION_PROPERTY_PREFIX);

                            ps.flush();

                        }

                    }

                }

                return lazy;

            }

            @SuppressFBWarnings(value = "DLS_DEAD_LOCAL_STORE", justification = "false positive on dead store to `ps`")

            private void printVMConfig(final boolean enableAutoflush, FileOutputStream result) {

                /*

                 * Add the JVM and Java arguments to the log file to help identity it.

                 */

                PrintStream ps = new PrintStream(result, enableAutoflush);

                List<String> inputArguments = GraalServices.getInputArguments();

                if (inputArguments != null) {

                    ps.println("VM Arguments: " + String.join(" ", inputArguments));

                }

                String cmd = Services.getSavedProperties().get("sun.java.command");

                if (cmd != null) {

                    ps.println("sun.java.command=" + cmd);

                }

            }

            @Override

            public void write(byte[] b, int off, int len) throws IOException {

                lazy().write(b, off, len);

            }

            @Override

            public void write(int b) throws IOException {

                lazy().write(b);

            }

            @Override

            public void flush() throws IOException {

                lazy().flush();

            }

            @Override

            public void close() throws IOException {

                lazy().close();

            }

        }

        /**

         * Gets the print stream configured by this option. If no file is configured, the print

         * stream will output to HotSpot's {@link HotSpotJVMCIRuntime#getLogStream() log} stream.

         */

        public PrintStream getStream() {

            return new PrintStream(new DelayedOutputStream());

        }

    }

}