/*

 * 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 jdk.vm.ci.common;

import java.util.concurrent.atomic.AtomicInteger;

/**

 * A facility for timing a step in the runtime initialization sequence. This is independent from all

 * other JVMCI code so as to not perturb the initialization sequence. It is enabled by setting the

 * {@code "jvmci.inittimer"} system property to {@code "true"}.

 */

public final class InitTimer implements AutoCloseable {

    private final String name;

    private final long start;

    private InitTimer(String name) {

        int n = nesting.getAndIncrement();

        if (n == 0) {

            initializingThread = Thread.currentThread();

            System.out.println("INITIALIZING THREAD: " + initializingThread);

        } else {

            assert Thread.currentThread() == initializingThread : Thread.currentThread() + " != " + initializingThread;

        }

        this.name = name;

        this.start = System.currentTimeMillis();

        System.out.println("START: " + SPACES.substring(0, n * 2) + name);

    }

    @Override

    @SuppressFBWarnings(value = "ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD", justification = "only the initializing thread accesses this field")

    public void close() {

        final long end = System.currentTimeMillis();

        int n = nesting.decrementAndGet();

        System.out.println(" DONE: " + SPACES.substring(0, n * 2) + name + " [" + (end - start) + " ms]");

        if (n == 0) {

            initializingThread = null;

        }

    }

    public static InitTimer timer(String name) {

    }

    public static InitTimer timer(String name, Object suffix) {

    }

    /**

     * {@code HotSpotJVMCIRuntime.Option} since that class is not visible from this package.

     */

    /**

     * Used to assert the invariant that all related initialization happens on the same thread.

     */

    static Thread initializingThread;

}