/*
 * Copyright (c) 2014-2015, Siemens AG. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <shared_mutex_test.h>
#include <embb/base/c/errors.h>

namespace embb {
namespace base {
namespace test {
SharedMutexTest::SharedMutexTest()
  : shared_mutex_(),
      counter_(0),
      num_threads_(partest::TestSuite::GetDefaultNumThreads()),
      num_iterations_(partest::TestSuite::GetDefaultNumIterations()) {
  CreateUnit("Shared read")
      .Pre(&SharedMutexTest::TestSharedReadPre, this)
      .Add(&SharedMutexTest::TestSharedReadThreadMethod, this,
           num_threads_, num_iterations_)
      .Post(&SharedMutexTest::TestSharedReadPost, this);
  CreateUnit("Multiple writer")
      .Pre(&SharedMutexTest::TestExclusiveWriterPre, this)
      .Add(&SharedMutexTest::TestExclusiveWriterReaderMethod, this,
           num_threads_ / 2, num_iterations_)
      .Add(&SharedMutexTest::TestExclusiveWriterWriterMethod, this,
           num_threads_ / 2, num_iterations_)
      .Post(&SharedMutexTest::TestExclusiveWriterPost, this);

  CreateUnit("Basic test: read lock after write lock fails")
    .Pre(&SharedMutexTest::TestLockedPre, this)
    .Add(&SharedMutexTest::TestLockedForWritingPreventsLockForReading
      , this, 2, num_iterations_)
     .Add(&SharedMutexTest::TestLockedPost, this);

  CreateUnit("Basic test: write lock after read lock fails")
    .Pre(&SharedMutexTest::TestLockedPre, this)
    .Add(&SharedMutexTest::TestLockedForReadingPreventsLockForWriting, this, 2,
    num_iterations_)
     .Add(&SharedMutexTest::TestLockedPost, this);
}

void SharedMutexTest::TestLockedPre() {
  embb_atomic_store_int(&synchronize_, 0);
  int success = embb_shared_mutex_init(&shared_mutex_);

  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to initialize shared mutex.");
}

void SharedMutexTest::TestLockedForWritingPreventsLockForReading() {
  int expected = 0;
  int success = 0;
  int which_thread = 0;

  if (embb_atomic_compare_and_swap_int(&synchronize_, &expected, 1)) {
    // we are the write locking thread (will happen first)!
    success = embb_shared_mutex_lock(&shared_mutex_);

    PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS,
      "Failed to lock shared mutex for writing");

    // signal the second thread to continue
    embb_atomic_store_int(&synchronize_, 2);
  } else {
    while (embb_atomic_load_int(&synchronize_) != 2) {}
    // we are the read lock thread! (second thread)
    which_thread = 1;

    // the mutex is locked for writing... try lock for reading must fail now!
    success = embb_shared_mutex_try_lock_shared(&shared_mutex_);

    PT_ASSERT_EQ_MSG(success, EMBB_BUSY,
     "Not failed to lock shared mutex for reading");

    // synchronize, that first thread can unlock
    embb_atomic_store_int(&synchronize_, 3);
  }

  if (which_thread == 0) {
    // wait for second thread to finish!
    while (embb_atomic_load_int(&synchronize_) != 3) {}

    // the first thread unlocks the mutex...
    success = embb_shared_mutex_unlock(&shared_mutex_);

    PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS,
      "Failed to unlock mutex");

    // reset synchronize flag for next round...
    embb_atomic_store_int(&synchronize_, 0);
  } else {
    //wait for next round
    while (embb_atomic_load_int(&synchronize_) == 3) {}
  }
}

void SharedMutexTest::TestLockedForReadingPreventsLockForWriting() {
  int expected = 0;
  int success = 0;
  int which_thread = 0;

  if (embb_atomic_compare_and_swap_int(&synchronize_, &expected, 1)) {
    // we are the write locking thread (will happen first)!
    success = embb_shared_mutex_lock_shared(&shared_mutex_);

    PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS,
      "Failed to lock shared mutex for writing");

    // signal the second thread to continue
    embb_atomic_store_int(&synchronize_, 2);
  } else {
    while (embb_atomic_load_int(&synchronize_) != 2) {}
    // we are the read lock thread! (second thread)
    which_thread = 1;

    // the mutex is locked for writing... try lock for reading must fail now!
    success = embb_shared_mutex_try_lock(&shared_mutex_);

    PT_ASSERT_EQ_MSG(success, EMBB_BUSY,
     "Not failed to lock shared mutex for reading");

    // synchronize, that first thread can unlock
    embb_atomic_store_int(&synchronize_, 3);
  }

  if (which_thread == 0) {
    // wait for second thread to finish!
    while (embb_atomic_load_int(&synchronize_) != 3) {}

    // the first thread unlocks the mutex...
    success = embb_shared_mutex_unlock(&shared_mutex_);

    PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS,
      "Failed to unlock mutex");

    // reset synchronize flag for next round...
    embb_atomic_store_int(&synchronize_, 0);
  } else {
    //wait for next round
    while (embb_atomic_load_int(&synchronize_) == 3) {}
  }
}

void SharedMutexTest::TestLockedPost() {
  embb_shared_mutex_destroy(&shared_mutex_);
}

void SharedMutexTest::TestSharedReadPre() {
  int success = embb_shared_mutex_init(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to initialize shared mutex.");
}

void SharedMutexTest::TestSharedReadThreadMethod() {
  int success = embb_shared_mutex_try_lock_shared(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to try-lock for reading.");

  success = embb_shared_mutex_unlock_shared(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to unlock (reading).");

  success = embb_shared_mutex_lock_shared(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to lock for reading.");

  success = embb_shared_mutex_unlock_shared(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to unlock (reading).");
}

void SharedMutexTest::TestSharedReadPost() {
  embb_shared_mutex_destroy(&shared_mutex_);
}

void SharedMutexTest::TestExclusiveWriterPre() {
  int success = embb_shared_mutex_init(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to initialize shared mutex.");

  counter_ = 0;
}

void SharedMutexTest::TestExclusiveWriterReaderMethod() {
  // Just add some contention

  int success = embb_shared_mutex_lock_shared(&shared_mutex_);
  if (success != EMBB_SUCCESS) return;

  success = embb_shared_mutex_unlock_shared(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to unlock (reading).");
}

void SharedMutexTest::TestExclusiveWriterWriterMethod() {
  int success = embb_shared_mutex_lock(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to lock for writing.");

  ++counter_;

  success = embb_shared_mutex_unlock(&shared_mutex_);
  PT_ASSERT_EQ_MSG(success, EMBB_SUCCESS, "Failed to unlock (writing).");
}

void SharedMutexTest::TestExclusiveWriterPost() {
  PT_ASSERT_EQ_MSG(counter_, num_iterations_ * (num_threads_ / 2),
                   "Counter value is inconsistent.");
  embb_shared_mutex_destroy(&shared_mutex_);
}
} // namespace test
} // namespace base
} // namespace embb