/* Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program 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 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "my_config.h"

#include <gtest/gtest.h>
#include <stddef.h>
#include <sys/types.h>

#include "my_inttypes.h"
#include "my_io.h"
#include "sql/handler.h"
#include "sql/mysqld.h"
#include "sql/sql_class.h"
#include "sql/tc_log.h"
#include "sql/transaction_info.h"
#include "unittest/gunit/test_utils.h"
#include "unittest/gunit/thread_utils.h"

#ifdef _WIN32
#include <process.h>  // getpid
#endif

using my_testing::Server_initializer;

/**
  Override msync/fsync, saves a *lot* of time during unit testing.
*/

class TC_LOG_MMAP_no_msync : public TC_LOG_MMAP {
 protected:
  virtual int do_msync_and_fsync(int, void *, size_t, int) { return 0; }
};

/**
  This class is a friend of TC_LOG_MMAP, so it needs to be outside the unittest
  namespace.
*/

class TCLogMMapTest : public ::testing::Test {
 public:
  TCLogMMapTest() : tc_log_mmap(nullptr) {}

  virtual void SetUp() {
    initializer.SetUp();
    total_ha_2pc = 2;
    tc_heuristic_recover = TC_HEURISTIC_NOT_USED;
    /*
      Assign a transaction coordinator object to am
      instance of TCLogMMapTest. This transaction coordinator
      is shared among all threads are run.
    */

    tc_log_mmap = new TC_LOG_MMAP_no_msync();
    // Make a slightly randomized name for the file,
    // to avoid recovery from other runs.
    char namebuff[FN_REFLEN];
    snprintf(namebuff, FN_REFLEN, "tc_log_mmap_test_%d",
             static_cast<int>(getpid()));
    ASSERT_EQ(0, tc_log_mmap->open(namebuff));
  }

  virtual void TearDown() {
    tc_log_mmap->close();
    delete tc_log_mmap;
    initializer.TearDown();
  }

  THD *thd() { return initializer.thd(); }

  /**
    Run test case in single threaded environment.
    This method uses THD value hold by the initializer data member.
  */

  void testCommit(ulonglong xid) { testCommit(xid, thd()); }

  /**
    Run a test case with the THD supplied outside. This method is used
    when there are several threads running the same test case. In this case
    we need a dedicated THD object for every thread in order not to hit
    upon the wrong condition when two threads free a memroot (indirectly by
    calling thd->get_transaction()->cleanup()) for the same THD object.
  */

  void testCommit(ulonglong xid, THD *thd_val) {
    XID_STATE *xid_state = thd_val->get_transaction()->xid_state();
    xid_state->set_query_id(xid);
    EXPECT_EQ(TC_LOG_MMAP::RESULT_SUCCESS, tc_log_mmap->commit(thd_val, true));
    thd_val->get_transaction()->cleanup();
  }

  ulong testLog(ulonglong xid) { return tc_log_mmap->log_xid(xid); }

  void testUnlog(ulong cookie, ulonglong xid) {
    tc_log_mmap->unlog(cookie, xid);
  }

 protected:
  TC_LOG_MMAP_no_msync *tc_log_mmap;
  Server_initializer initializer;
};

namespace tc_log_mmap_unittest {

TEST_F(TCLogMMapTest, TClogCommit) {
  // test calling of log/unlog for xid=1
  testCommit(1);
}

class TC_Log_MMap_thread : public thread::Thread {
 public:
  TC_Log_MMap_thread()
      : m_start_xid(0),
        m_end_xid(0),
        m_tc_log_mmap(nullptr),
        initializer(nullptr) {}

  ~TC_Log_MMap_thread() {
    initializer->TearDown();
    delete initializer;
  }

  void init(ulonglong start_value, ulonglong end_value,
            TCLogMMapTest *tc_log_mmap, Server_initializer *initializer_value) {
    m_start_xid = start_value;
    m_end_xid = end_value;
    m_tc_log_mmap = tc_log_mmap;
    initializer = initializer_value;
    initializer->SetUp();
  }

  virtual void run() {
    ulonglong xid = m_start_xid;
    while (xid < m_end_xid) {
      m_tc_log_mmap->testCommit(xid++, initializer->thd());
    }
  }

 protected:
  ulonglong m_start_xid, m_end_xid;
  TCLogMMapTest *m_tc_log_mmap;
  Server_initializer *initializer;
};

TEST_F(TCLogMMapTest, ConcurrentAccess) {
  static const unsigned MAX_WORKER_THREADS = 10;
  static const unsigned VALUE_INTERVAL = 100;

  TC_Log_MMap_thread tclog_threads[MAX_WORKER_THREADS];

  ulonglong start_value = 0;
  for (unsigned i = 0; i < MAX_WORKER_THREADS; ++i) {
    /*
      Each thread gets a dedicated instance of class Server_initializer and
      hence it also gets a separate THD object.
    */
    tclog_threads[i].init(start_value, start_value + VALUE_INTERVAL, this,
                          new Server_initializer());
    tclog_threads[i].start();
    start_value += VALUE_INTERVAL;
  }

  for (unsigned i = 0; i < MAX_WORKER_THREADS; ++i) tclog_threads[i].join();
}

TEST_F(TCLogMMapTest, FillAllPagesAndReuse) {
  /* Get maximum number of XIDs which can be stored in TC log. */
  const uint MAX_XIDS = tc_log_mmap->size();
  ulong cookie;
  /* Fill TC log. */
  for (my_xid xid = 1; xid < MAX_XIDS; ++xid) (void)testLog(xid);
  cookie = testLog(MAX_XIDS);
  /*
    Now free one slot and try to reuse it.
    This should work and not crash on assert.
  */
  testUnlog(cookie, MAX_XIDS);
  testLog(MAX_XIDS + 1);
}

TEST_F(TCLogMMapTest, ConcurrentOverflow) {
  const uint WORKER_THREADS = 10;
  const uint XIDS_TO_REUSE = 100;

  /*
    Get maximum number of XIDs which can be stored in TC log.
  */
  const uint MAX_XIDS = tc_log_mmap->size();
  ulong cookies[XIDS_TO_REUSE];

  /*
    Fill TC log. Remember cookies for last XIDS_TO_REUSE xids.
  */
  for (my_xid xid = 1; xid <= MAX_XIDS - XIDS_TO_REUSE; ++xid) testLog(xid);
  for (uint i = 0; i < XIDS_TO_REUSE; ++i)
    cookies[i] = testLog(MAX_XIDS - XIDS_TO_REUSE + 1 + i);

  /*
    Now create several threads which will try to do commit.
    Since log is full they will have to wait until we free some slots.
  */
  TC_Log_MMap_thread threads[WORKER_THREADS];
  for (uint i = 0; i < WORKER_THREADS; ++i) {
    /*
      Each thread gets a dedicated instance of class Server_initializer and
      hence it also gets a separate THD object.
    */
    threads[i].init(MAX_XIDS + i * (XIDS_TO_REUSE / WORKER_THREADS),
                    MAX_XIDS + (i + 1) * (XIDS_TO_REUSE / WORKER_THREADS), this,
                    new Server_initializer());
    threads[i].start();
  }

  /*
    Once started all threads should block since we are out of free slots
    in the log, Resume threads by freeing necessary slots. Resumed thread
    should not hang or assert.
  */
  for (uint i = 0; i < XIDS_TO_REUSE; ++i)
    testUnlog(cookies[i], MAX_XIDS - XIDS_TO_REUSE + 1 + i);

  /* Wait till all threads are done. */
  for (uint i = 0; i < WORKER_THREADS; ++i) threads[i].join();
}

}  // namespace tc_log_mmap_unittest