/*

 * Copyright (c) 2016, 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 java.util.Formatter;

/**

 * Mechanism for checking that the current Java runtime environment supports the minimum JVMCI API

 * required by Graal. The {@code JVMCI_VERSION_CHECK} environment variable can be used to ignore a

 * failed check ({@code JVMCI_VERSION_CHECK=ignore}) or print a warning (

 * {@code JVMCI_VERSION_CHECK=warn}) and continue. Otherwise, a failed check results in an

 * {@link InternalError} being raised or, if called from {@link #main(String[])}, the VM exiting

 * with a result code of {@code -1}

 *

 * This class only depends on the JDK so that it can be used without building Graal.

 */

class JVMCIVersionCheck {

    private static final int JVMCI8_MIN_MAJOR_VERSION = 0;

    private static void failVersionCheck(boolean exit, String reason, Object... args) {

        Formatter errorMessage = new Formatter().format(reason, args);

        String javaHome = System.getProperty("java.home");

        String vmName = System.getProperty("java.vm.name");

        errorMessage.format("Set the JVMCI_VERSION_CHECK environment variable to \"ignore\" to suppress ");

        errorMessage.format("this error or to \"warn\" to emit a warning and continue execution.%n");

        errorMessage.format("Currently used Java home directory is %s.%n", javaHome);

        errorMessage.format("Currently used VM configuration is: %s%n", vmName);

        if (System.getProperty("java.specification.version").compareTo("1.9") < 0) {

            errorMessage.format("Download the latest JVMCI JDK 8 from http://www.oracle.com/technetwork/oracle-labs/program-languages/downloads/index.html");

        } else {

            errorMessage.format("Download the latest JDK 9 EA from https://jdk9.java.net/download/");

        }

        String value = System.getenv("JVMCI_VERSION_CHECK");

        if ("warn".equals(value)) {

            System.err.println(errorMessage.toString());

        } else if ("ignore".equals(value)) {

            return;

        } else if (exit) {

            System.err.println(errorMessage.toString());

            System.exit(-1);

        } else {

            throw new InternalError(errorMessage.toString());

        }

    }

    static void check(boolean exitOnFailure) {

        // Don't use regular expressions to minimize Graal startup time

        String vmVersion = System.getProperty("java.vm.version");

        if (System.getProperty("java.specification.version").compareTo("1.9") < 0) {

            int start = vmVersion.indexOf("-jvmci-");

            if (start >= 0) {

                start += "-jvmci-".length();

                int end = vmVersion.indexOf('.', start);

                if (end > 0) {

                    start = end + 1;

                    end = start;

                    while (end < vmVersion.length() && Character.isDigit(vmVersion.charAt(end))) {

                        end++;

                    }

                    if (major >= JVMCI8_MIN_MAJOR_VERSION && minor >= JVMCI8_MIN_MINOR_VERSION) {

                        return;

                    }

                    failVersionCheck(exitOnFailure, "The VM does not support the minimum JVMCI API version required by Graal: %d.%d < %d.%d.%n",

                                    major, minor, JVMCI8_MIN_MAJOR_VERSION, JVMCI8_MIN_MINOR_VERSION);

                    return;

                }

            }

            failVersionCheck(exitOnFailure, "The VM does not support the minimum JVMCI API version required by Graal.%n" +

                            "Cannot read JVMCI version from java.vm.version property: %s.%n", vmVersion);

        } else {

            if (vmVersion.contains("SNAPSHOT")) {

                return;

            }

            if (vmVersion.contains("internal")) {

                // Allow local builds

                return;

            }

            // http://openjdk.java.net/jeps/223

                int end = start;

                end = start;

                while (end < vmVersion.length() && Character.isDigit(vmVersion.charAt(end))) {

                    end++;

                }

                if (build >= JVMCI9_MIN_EA_BUILD) {

                    return;

                }

                return;

            }

        }

    }

    /**

     * Command line interface for performing the check.

     */

    public static void main(String[] args) {

        check(true);

    }

}