/*

 * Copyright (c) 2012, 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

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 * questions.

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 */

#ifndef SHARE_VM_JFR_RECORDER_SERVICE_JFREVENT_HPP

#define SHARE_VM_JFR_RECORDER_SERVICE_JFREVENT_HPP

#include "jfr/recorder/jfrEventSetting.inline.hpp"

#include "jfr/recorder/stacktrace/jfrStackTraceRepository.hpp"

#include "jfr/utilities/jfrTime.hpp"

#include "jfr/utilities/jfrTypes.hpp"

#include "jfr/writers/jfrNativeEventWriter.hpp"

#include "runtime/thread.hpp"

#include "utilities/exceptions.hpp"

#include "utilities/ticks.hpp"

#ifdef ASSERT

#include "utilities/bitMap.hpp"

#endif

#ifdef ASSERT

class JfrEventVerifier {

  template <typename>

  friend class JfrEvent;

 private:

  // verification of event fields

  BitMap::bm_word_t _verification_storage[1];

  BitMapView _verification_bit_map;

  bool _committed;

  JfrEventVerifier();

  void check(BitMap::idx_t field_idx) const;

  void set_field_bit(size_t field_idx);

  bool verify_field_bit(size_t field_idx) const;

  void set_committed();

  void clear_committed();

  bool committed() const;

};

#endif // ASSERT

template <typename T>

class JfrEvent {

 private:

  jlong _start_time;

  jlong _end_time;

  bool _started;

 protected:

  JfrEvent(EventStartTime timing=TIMED) : _start_time(0), _end_time(0), _started(false)

#ifdef ASSERT

  , _verifier()

#endif

  {

    if (T::is_enabled()) {

      _started = true;

      if (TIMED == timing && !T::isInstant) {

        set_starttime(JfrTicks::now());

      }

    }

  }

  void commit() {

    if (!should_commit()) {

      return;

    }

    assert(!_verifier.committed(), "event already committed");

    if (_start_time == 0) {

      set_starttime(JfrTicks::now());

    } else if (_end_time == 0) {

      set_endtime(JfrTicks::now());

    }

    if (should_write()) {

      write_event();

      DEBUG_ONLY(_verifier.set_committed();)

    }

  }

 public:

  void set_starttime(const JfrTicks& time) {

    _start_time = time.value();

  }

  void set_endtime(const JfrTicks& time) {

    _end_time = time.value();

  }

  void set_starttime(const Ticks& time) {

    _start_time = JfrTime::is_ft_enabled() ? time.ft_value() : time.value();

  }

  void set_endtime(const Ticks& time) {

    _end_time = JfrTime::is_ft_enabled() ? time.ft_value() : time.value();

  }

  static bool is_enabled() {

    return JfrEventSetting::is_enabled(T::eventId);

  }

  static bool is_stacktrace_enabled() {

    return JfrEventSetting::has_stacktrace(T::eventId);

  }

  static JfrEventId id() {

    return T::eventId;

  }

  static bool is_instant() {

    return T::isInstant;

  }

  static bool is_requestable() {

    return T::isRequestable;

  }

  static bool has_thread() {

    return T::hasThread;

  }

  static bool has_stacktrace() {

    return T::hasStackTrace;

  }

  bool should_commit() {

    return _started;

  }

 private:

  bool should_write() {

    if (T::isInstant || T::isRequestable || T::hasCutoff) {

      return true;

    }

    return (_end_time - _start_time) >= JfrEventSetting::threshold(T::eventId);

  }

  void write_event() {

    DEBUG_ONLY(assert_precondition();)

    Thread* const event_thread = Thread::current();

    JfrThreadLocal* const tl = event_thread->jfr_thread_local();

    JfrBuffer* const buffer = tl->native_buffer();

    if (buffer == NULL) {

      // most likely a pending OOM

      return;

    }

    JfrNativeEventWriter writer(buffer, event_thread);

    writer.write<u8>(T::eventId);

    assert(_start_time != 0, "invariant");

    writer.write(_start_time);

    if (!(T::isInstant || T::isRequestable) || T::hasCutoff) {

      assert(_end_time != 0, "invariant");

      writer.write(_end_time - _start_time);

    }

    if (T::hasThread) {

      writer.write(tl->thread_id());

    }

    if (T::hasStackTrace) {

      if (is_stacktrace_enabled()) {

        if (tl->has_cached_stack_trace()) {

          writer.write(tl->cached_stack_trace_id());

        } else {

          writer.write(JfrStackTraceRepository::record(event_thread));

        }

      } else {

        writer.write<traceid>(0);

      }

    }

    // payload

    static_cast<T*>(this)->writeData(writer);

  }

#ifdef ASSERT

 private:

  // verification of event fields

  JfrEventVerifier _verifier;

  void assert_precondition() {

    assert(T::eventId >= (JfrEventId)NUM_RESERVED_EVENTS, "event id underflow invariant");

    assert(T::eventId < MaxJfrEventId, "event id overflow invariant");

    DEBUG_ONLY(static_cast<T*>(this)->verify());

  }

 protected:

  void set_field_bit(size_t field_idx) {

    _verifier.set_field_bit(field_idx);

    // it is ok to reuse an already committed event

    // granted you provide new informational content

    _verifier.clear_committed();

  }

  bool verify_field_bit(size_t field_idx) const {

    return _verifier.verify_field_bit(field_idx);

  }

#endif // ASSERT

};

#endif // SHARE_VM_JFR_RECORDER_SERVICE_JFREVENT_HPP