/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 **/

#include "transaction/LockTable.hpp"

#include "transaction/AccessMode.hpp"
#include "transaction/ResourceId.hpp"
#include "transaction/Transaction.hpp"

#include "gtest/gtest.h"

namespace quickstep {
namespace transaction {

class LockTableTest : public ::testing::Test {
 protected:
  LockTableTest()
      : tid_1_(1),
        tid_2_(2),
        tid_3_(3) {
  }

  LockTable lock_table_;
  const transaction_id tid_1_;
  const transaction_id tid_2_;
  const transaction_id tid_3_;
};

TEST_F(LockTableTest, CompatibleRequestsFromDifferentTransactions) {
  const AccessMode is_lock_mode = AccessMode::IsLockMode();
  const AccessMode s_lock_mode = AccessMode::SLockMode();

  EXPECT_EQ(LockTableResult::kPlacedInOwned,
            lock_table_.putLock(tid_1_,
                                ResourceId(2),
                                is_lock_mode));

  // Acquire the same lock mode on same resource.
  EXPECT_EQ(LockTableResult::kAlreadyInOwned,
            lock_table_.putLock(tid_1_,
                                ResourceId(2),
                                is_lock_mode));

  // Another transaction acquires compatible lock on the same resource.
  EXPECT_EQ(LockTableResult::kPlacedInOwned,
            lock_table_.putLock(tid_2_,
                                ResourceId(2),
                                s_lock_mode));
}

TEST_F(LockTableTest, IncompatibleRequestsFromDifferentTransactions) {
  const AccessMode is_lock_mode = AccessMode::IsLockMode();
  const AccessMode x_lock_mode = AccessMode::XLockMode();

  EXPECT_EQ(LockTableResult::kPlacedInOwned,
            lock_table_.putLock(tid_1_,
                                ResourceId(2),
                                is_lock_mode));

  // Acquire the same lock mode on same resource.
  EXPECT_EQ(LockTableResult::kAlreadyInOwned,
            lock_table_.putLock(tid_1_,
                                ResourceId(2),
                                is_lock_mode));

  // Another transaction acquires incompatible lock on the same resource.
  EXPECT_EQ(LockTableResult::kPlacedInPending,
            lock_table_.putLock(tid_2_,
                                ResourceId(2),
                                x_lock_mode));
}

TEST_F(LockTableTest, StarvationProtection) {
  const AccessMode is_lock_mode = AccessMode::IsLockMode();
  const AccessMode x_lock_mode = AccessMode::XLockMode();

  EXPECT_EQ(LockTableResult::kPlacedInOwned,
            lock_table_.putLock(tid_1_,
                                ResourceId(2),
                                is_lock_mode));

  // Another transaction requests incompatible lock on the same resource.
  // It should wait for the previous transaction.
  EXPECT_EQ(LockTableResult::kPlacedInPending,
            lock_table_.putLock(tid_2_,
                                ResourceId(2),
                                x_lock_mode));

  // Another third transaction requests a compatible lock on the same resource.
  // Normally, it should acquire the lock, however, there is a pending
  // transaction waiting on the same resource. To prevent starvation, we should
  // put in the pending list.
  EXPECT_EQ(LockTableResult::kPlacedInPending,
            lock_table_.putLock(tid_3_,
                                ResourceId(2),
                                is_lock_mode));
}

}  // namespace transaction
}  // namespace quickstep