/*

 * Copyright (c) 2002, 2015, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_VM_GC_SHARED_GCCAUSE_HPP

#define SHARE_VM_GC_SHARED_GCCAUSE_HPP

#include "memory/allocation.hpp"

//

// This class exposes implementation details of the various

// collector(s), and we need to be very careful with it. If

// use of this class grows, we should split it into public

// and implementation-private "causes".

//

class GCCause : public AllStatic {

 public:

  enum Cause {

    /* public */

    _java_lang_system_gc,

    _full_gc_alot,

    _scavenge_alot,

    _allocation_profiler,

    _jvmti_force_gc,

    _gc_locker,

    _heap_inspection,

    _heap_dump,

    _wb_young_gc,

    _wb_conc_mark,

    _update_allocation_context_stats_inc,

    _update_allocation_context_stats_full,

    /* implementation independent, but reserved for GC use */

    _no_gc,

    _no_cause_specified,

    _allocation_failure,

    /* implementation specific */

    _tenured_generation_full,

    _metadata_GC_threshold,

    _cms_generation_full,

    _cms_initial_mark,

    _cms_final_remark,

    _cms_concurrent_mark,

    _old_generation_expanded_on_last_scavenge,

    _old_generation_too_full_to_scavenge,

    _adaptive_size_policy,

    _g1_inc_collection_pause,

    _g1_humongous_allocation,

    _last_ditch_collection,

    _dcmd_gc_run,

    _last_gc_cause

  };

  inline static bool is_user_requested_gc(GCCause::Cause cause) {

    return (cause == GCCause::_java_lang_system_gc ||

            cause == GCCause::_dcmd_gc_run);

  }

  inline static bool is_serviceability_requested_gc(GCCause::Cause

                                                             cause) {

    return (cause == GCCause::_jvmti_force_gc ||

            cause == GCCause::_heap_inspection ||

            cause == GCCause::_heap_dump);

  }

  // Causes for collection of the tenured gernation

  inline static bool is_tenured_allocation_failure_gc(GCCause::Cause cause) {

    assert(cause != GCCause::_old_generation_too_full_to_scavenge &&

           cause != GCCause::_old_generation_expanded_on_last_scavenge,

           "This GCCause may be correct but is not expected yet: %s",

           to_string(cause));

    // _tenured_generation_full or _cms_generation_full for full tenured generations

    // _adaptive_size_policy for a full collection after a young GC

    // _allocation_failure is the generic cause a collection which could result

    // in the collection of the tenured generation if there is not enough space

    // in the tenured generation to support a young GC.

    // _last_ditch_collection is a collection done to include SoftReferences.

    return (cause == GCCause::_tenured_generation_full ||

            cause == GCCause::_cms_generation_full ||

            cause == GCCause::_adaptive_size_policy ||

            cause == GCCause::_allocation_failure ||

            cause == GCCause::_last_ditch_collection);

  }

  // Causes for collection of the young generation

  inline static bool is_allocation_failure_gc(GCCause::Cause cause) {

    // _allocation_failure is the generic cause a collection for allocation failure

    // _adaptive_size_policy is for a collecton done before a full GC

    // _last_ditch_collection is a collection done to include SoftReferences.

    return (cause == GCCause::_allocation_failure ||

            cause == GCCause::_adaptive_size_policy ||

            cause == GCCause::_last_ditch_collection);

  }

  // Return a string describing the GCCause.

  static const char* to_string(GCCause::Cause cause);

};

// Helper class for doing logging that includes the GC Cause

// as a string.

class GCCauseString : StackObj {

 private:

   static const int _length = 128;

   char _buffer[_length];

   int _position;

 public:

   GCCauseString(const char* prefix, GCCause::Cause cause) {

     if (PrintGCCause) {

      _position = jio_snprintf(_buffer, _length, "%s (%s) ", prefix, GCCause::to_string(cause));

     } else {

      _position = jio_snprintf(_buffer, _length, "%s ", prefix);

     }

     assert(_position >= 0 && _position <= _length,

            "Need to increase the buffer size in GCCauseString? %d", _position);

   }

   GCCauseString& append(const char* str) {

     int res = jio_snprintf(_buffer + _position, _length - _position, "%s", str);

     _position += res;

     assert(res >= 0 && _position <= _length,

            "Need to increase the buffer size in GCCauseString? %d", res);

     return *this;

   }

   operator const char*() {

     return _buffer;

   }

};

#endif // SHARE_VM_GC_SHARED_GCCAUSE_HPP