/*

 * Copyright (c) 2018, 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.

 */

#include "precompiled.hpp"

#include "metaprogramming/isRegisteredEnum.hpp"

#include "runtime/atomic.hpp"

#include "runtime/orderAccess.hpp"

#include "runtime/os.hpp"

#include "utilities/globalCounter.hpp"

#include "utilities/globalCounter.inline.hpp"

#include "utilities/spinYield.hpp"

#include "threadHelper.inline.hpp"

enum NestedTestState {

  START,

  START_WAIT,

  OUTER_ENTERED,

  INNER_ENTERED,

  INNER_EXITED,

  OUTER_EXITED,

  SYNCHRONIZING,

  SYNCHRONIZED

};

template<> struct IsRegisteredEnum<NestedTestState> : public TrueType {};

class RCUNestedThread : public JavaTestThread {

  volatile NestedTestState _state;

  volatile bool _proceed;

protected:

  RCUNestedThread(Semaphore* post) :

    JavaTestThread(post),

    _state(START),

    _proceed(false)

  {}

  ~RCUNestedThread() {}

  void set_state(NestedTestState new_state) {

    OrderAccess::release_store(&_state, new_state);

  }

  void wait_with_state(NestedTestState new_state) {

    SpinYield spinner;

    OrderAccess::release_store(&_state, new_state);

    while (!OrderAccess::load_acquire(&_proceed)) {

      spinner.wait();

    }

    OrderAccess::release_store(&_proceed, false);

  }

public:

  NestedTestState state() const {

    return OrderAccess::load_acquire(&_state);

  }

  void wait_for_state(NestedTestState goal) {

    SpinYield spinner;

    while (state() != goal) {

      spinner.wait();

    }

  }

  void proceed() {

    OrderAccess::release_store(&_proceed, true);

  }

};

class RCUNestedReaderThread : public RCUNestedThread {

public:

  RCUNestedReaderThread(Semaphore* post) :

    RCUNestedThread(post)

  {}

  virtual void main_run();

};

void RCUNestedReaderThread::main_run() {

  wait_with_state(START_WAIT);

  {

    GlobalCounter::CriticalSection outer(Thread::current());

    wait_with_state(OUTER_ENTERED);

    {

      GlobalCounter::CriticalSection inner(Thread::current());

      wait_with_state(INNER_ENTERED);

    }

    wait_with_state(INNER_EXITED);

  }

  wait_with_state(OUTER_EXITED);

}

class RCUNestedWriterThread : public RCUNestedThread {

public:

  RCUNestedWriterThread(Semaphore* post) :

    RCUNestedThread(post)

  {}

  virtual void main_run();

};

void RCUNestedWriterThread::main_run() {

  wait_with_state(START_WAIT);

  set_state(SYNCHRONIZING);

  GlobalCounter::write_synchronize();

  wait_with_state(SYNCHRONIZED);

}

TEST_VM(GlobalCounter, nested_critical_section) {

  Semaphore post;

  RCUNestedReaderThread* reader = new RCUNestedReaderThread(&post);

  RCUNestedWriterThread* outer = new RCUNestedWriterThread(&post);

  RCUNestedWriterThread* inner = new RCUNestedWriterThread(&post);

  reader->doit();

  outer->doit();

  inner->doit();

  reader->wait_for_state(START_WAIT);

  outer->wait_for_state(START_WAIT);

  inner->wait_for_state(START_WAIT);

  EXPECT_EQ(START_WAIT, reader->state());

  EXPECT_EQ(START_WAIT, outer->state());

  EXPECT_EQ(START_WAIT, inner->state());

  reader->proceed();

  reader->wait_for_state(OUTER_ENTERED);

  EXPECT_EQ(OUTER_ENTERED, reader->state());

  EXPECT_EQ(START_WAIT, outer->state());

  EXPECT_EQ(START_WAIT, inner->state());

  outer->proceed();

  outer->wait_for_state(SYNCHRONIZING);

  EXPECT_EQ(OUTER_ENTERED, reader->state());

  EXPECT_EQ(SYNCHRONIZING, outer->state());

  EXPECT_EQ(START_WAIT, inner->state());

  os::naked_short_sleep(100);   // Give outer time in synchronization.

  EXPECT_EQ(OUTER_ENTERED, reader->state());

  EXPECT_EQ(SYNCHRONIZING, outer->state());

  EXPECT_EQ(START_WAIT, inner->state());

  reader->proceed();

  reader->wait_for_state(INNER_ENTERED);

  EXPECT_EQ(INNER_ENTERED, reader->state());

  EXPECT_EQ(SYNCHRONIZING, outer->state());

  EXPECT_EQ(START_WAIT, inner->state());

  inner->proceed();

  inner->wait_for_state(SYNCHRONIZING);

  EXPECT_EQ(INNER_ENTERED, reader->state());

  EXPECT_EQ(SYNCHRONIZING, outer->state());

  EXPECT_EQ(SYNCHRONIZING, inner->state());

  os::naked_short_sleep(100); // Give writers time in synchronization.

  EXPECT_EQ(INNER_ENTERED, reader->state());

  EXPECT_EQ(SYNCHRONIZING, outer->state());

  EXPECT_EQ(SYNCHRONIZING, inner->state());

  reader->proceed();

  reader->wait_for_state(INNER_EXITED);

  // inner does *not* complete synchronization here.

  EXPECT_EQ(INNER_EXITED, reader->state());

  EXPECT_EQ(SYNCHRONIZING, outer->state());

  EXPECT_EQ(SYNCHRONIZING, inner->state());

  os::naked_short_sleep(100); // Give writers more time in synchronization.

  EXPECT_EQ(INNER_EXITED, reader->state());

  EXPECT_EQ(SYNCHRONIZING, outer->state());

  EXPECT_EQ(SYNCHRONIZING, inner->state());

  reader->proceed();

  reader->wait_for_state(OUTER_EXITED);

  // Both inner and outer can synchronize now.

  outer->wait_for_state(SYNCHRONIZED);

  inner->wait_for_state(SYNCHRONIZED);

  EXPECT_EQ(OUTER_EXITED, reader->state());

  EXPECT_EQ(SYNCHRONIZED, outer->state());

  EXPECT_EQ(SYNCHRONIZED, inner->state());

  // Wait for reader, outer, and inner to complete.

  reader->proceed();

  outer->proceed();

  inner->proceed();

  for (uint i = 0; i < 3; ++i) {

    post.wait();

  }

}