FailureInducer.h

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/* -*- c++ -*-
 * Copyright (C) 2007-2015 Hypertable, Inc.
 *
 * This file is part of Hypertable.
 *
 * Hypertable is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or any later version.
 *
 * Hypertable 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 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 Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

#ifndef Common_FailureInducer_h
#define Common_FailureInducer_h

#include <Common/String.h>
#include <Common/StringExt.h>

#include <mutex>
#include <unordered_map>

namespace Hypertable {

  class FailureInducer {
  public:
    static FailureInducer *instance;

    static bool enabled() { return instance != 0; }

    void parse_option(String spec);

    void maybe_fail(const String &label);

    bool failure_signalled(const String &label);

    void clear();

  private:
    void parse_option_single(String option);

    struct failure_inducer_state {
      uint32_t iteration;
      uint32_t trigger_iteration;
      int failure_type;
      int error_code;
      int pause_millis;
    };

    typedef std::unordered_map<String, failure_inducer_state *> StateMap;

    std::mutex m_mutex;

    StateMap m_state_map;
  };

}

/* Convenience macro which tests if a failure should be induced; if yes then an
 * error is thrown/returned or the application pauses/exits
 */
#define HT_MAYBE_FAIL(_label_) \
  if (Hypertable::FailureInducer::enabled()) { \
    Hypertable::FailureInducer::instance->maybe_fail(_label_); \
  }

/* Convenience macro which tests if a failure should be induced induced;
 * if yes then an error is thrown/returned or the application pauses/exits
 */
#define HT_MAYBE_FAIL_X(_label_, _exp_) \
  if (Hypertable::FailureInducer::enabled() && (_exp_)) { \
    Hypertable::FailureInducer::instance->maybe_fail(_label_); \
  }

/* Convenience macro for executing arbitrary code if a failure is induced */
#define HT_FAILURE_SIGNALLED(_label_) \
  Hypertable::FailureInducer::enabled() && \
    Hypertable::FailureInducer::instance->failure_signalled(_label_)

#endif // Common_FailureInducer_h