/*

 * Copyright 1997-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

#include "incls/_precompiled.incl"

#include "incls/_events.cpp.incl"

#ifndef PRODUCT

////////////////////////////////////////////////////////////////////////////

// Event

typedef u4 EventID;

class Event VALUE_OBJ_CLASS_SPEC  {

 private:

  jlong       _time_tick;

  intx        _thread_id;

  const char* _format;

  int         _indent;

  intptr_t    _arg_1;

  intptr_t    _arg_2;

  intptr_t    _arg_3;

  // only EventBuffer::add_event() can assign event id

  friend class EventBuffer;

  EventID     _id;

 public:

  void clear() { _format = NULL; }

  EventID id() const { return _id; }

  void fill(int indent, const char* format, intptr_t arg_1, intptr_t arg_2, intptr_t arg_3) {

    _format = format;

    _arg_1  = arg_1;

    _arg_2  = arg_2;

    _arg_3  = arg_3;

    _indent = indent;

    _thread_id = os::current_thread_id();

    _time_tick = os::elapsed_counter();

  }

  void print_on(outputStream *st) {

    if (_format == NULL) return;

    st->print("  %d", _thread_id);

    st->print("  %3.2g   ", (double)_time_tick / os::elapsed_frequency());

    st->fill_to(20);

    for (int index = 0; index < _indent; index++) {

      st->print("| ");

    }

    st->print_cr(_format, _arg_1, _arg_2, _arg_3);

  }

};

////////////////////////////////////////////////////////////////////////////

// EventBuffer

//

// Simple lock-free event queue. Every event has a unique 32-bit id.

// It's fine if two threads add events at the same time, because they

// will get different event id, and then write to different buffer location.

// However, it is assumed that add_event() is quick enough (or buffer size

// is big enough), so when one thread is adding event, there can't be more

// than "size" events created by other threads; otherwise we'll end up having

// two threads writing to the same location.

class EventBuffer : AllStatic {

 private:

  static Event* buffer;

  static int    size;

  static jint   indent;

  static volatile EventID _current_event_id;

  static EventID get_next_event_id() {

    return (EventID)Atomic::add(1, (jint*)&_current_event_id);

  }

 public:

  static void inc_indent() { Atomic::inc(&indent); }

  static void dec_indent() { Atomic::dec(&indent); }

  static bool get_event(EventID id, Event* event) {

    int index = (int)(id % size);

    if (buffer[index].id() == id) {

      memcpy(event, &buffer[index], sizeof(Event));

      // check id again; if buffer[index] is being updated by another thread,

      // event->id() will contain different value.

      return (event->id() == id);

    } else {

      // id does not match - id is invalid, or event is overwritten

      return false;

    }

  }

  // add a new event to the queue; if EventBuffer is full, this call will

  // overwrite the oldest event in the queue

  static EventID add_event(const char* format,

                           intptr_t arg_1, intptr_t arg_2, intptr_t arg_3) {

    // assign a unique id

    EventID id = get_next_event_id();

    // event will be copied to buffer[index]

    int index = (int)(id % size);

    // first, invalidate id, buffer[index] can't have event with id = index + 2

    buffer[index]._id = index + 2;

    // make sure everyone has seen that buffer[index] is invalid

    OrderAccess::fence();

    // ... before updating its value

    buffer[index].fill(indent, format, arg_1, arg_2, arg_3);

    // finally, set up real event id, now buffer[index] contains valid event

    OrderAccess::release_store(&(buffer[index]._id), id);

    return id;

  }

  static void print_last(outputStream *st, int number) {

    st->print_cr("[Last %d events in the event buffer]", number);

    st->print_cr("-<thd>-<elapsed sec>-<description>---------------------");

    int count = 0;

    EventID id = _current_event_id;

    while (count < number) {

      Event event;

      if (get_event(id, &event)) {

         event.print_on(st);

      }

      id--;

      count++;

    }

  }

  static void print_all(outputStream* st) {

    print_last(st, size);

  }

  static void init() {

    // Allocate the event buffer

    size   = EventLogLength;

    buffer = NEW_C_HEAP_ARRAY(Event, size);

    _current_event_id = 0;

    // Clear the event buffer

    for (int index = 0; index < size; index++) {

      buffer[index]._id = index + 1;       // index + 1 is invalid id

      buffer[index].clear();

    }

  }

};

Event*           EventBuffer::buffer;

int              EventBuffer::size;

volatile EventID EventBuffer::_current_event_id;

int              EventBuffer::indent;

////////////////////////////////////////////////////////////////////////////

// Events

// Events::log() is safe for signal handlers

void Events::log(const char* format, ...) {

  if (LogEvents) {

    va_list ap;

    va_start(ap, format);

    intptr_t arg_1 = va_arg(ap, intptr_t);

    intptr_t arg_2 = va_arg(ap, intptr_t);

    intptr_t arg_3 = va_arg(ap, intptr_t);

    va_end(ap);

    EventBuffer::add_event(format, arg_1, arg_2, arg_3);

  }

}

void Events::print_all(outputStream *st) {

  EventBuffer::print_all(st);

}

void Events::print_last(outputStream *st, int number) {

  EventBuffer::print_last(st, number);

}

///////////////////////////////////////////////////////////////////////////

// EventMark

EventMark::EventMark(const char* format, ...) {

  if (LogEvents) {

    va_list ap;

    va_start(ap, format);

    intptr_t arg_1 = va_arg(ap, intptr_t);

    intptr_t arg_2 = va_arg(ap, intptr_t);

    intptr_t arg_3 = va_arg(ap, intptr_t);

    va_end(ap);

    EventBuffer::add_event(format, arg_1, arg_2, arg_3);

    EventBuffer::inc_indent();

  }

}

EventMark::~EventMark() {

  if (LogEvents) {

    EventBuffer::dec_indent();

    EventBuffer::add_event("done", 0, 0, 0);

  }

}

///////////////////////////////////////////////////////////////////////////

void eventlog_init() {

  EventBuffer::init();

}

int print_all_events(outputStream *st) {

  EventBuffer::print_all(st);

  return 1;

}

#else

void eventlog_init() {}

int print_all_events(outputStream *st) { return 0; }

#endif // PRODUCT