/*

 * Copyright (c) 2011, 2017, 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.

 *

 */

#include "precompiled.hpp"

#include "classfile/systemDictionary.hpp"

#include "classfile/vmSymbols.hpp"

#include "oops/objArrayOop.inline.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/java.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/mutex.hpp"

#include "runtime/mutexLocker.hpp"

#include "services/gcNotifier.hpp"

#include "services/management.hpp"

#include "services/memoryService.hpp"

#include "memoryManager.hpp"

#include "memory/oopFactory.hpp"

#include "memory/resourceArea.hpp"

GCNotificationRequest *GCNotifier::first_request = NULL;

GCNotificationRequest *GCNotifier::last_request = NULL;

void GCNotifier::pushNotification(GCMemoryManager *mgr, const char *action, const char *cause) {

  // Make a copy of the last GC statistics

  // GC may occur between now and the creation of the notification

  int num_pools = MemoryService::num_memory_pools();

  // stat is deallocated inside GCNotificationRequest

  GCStatInfo* stat = new(ResourceObj::C_HEAP, mtGC) GCStatInfo(num_pools);

  mgr->get_last_gc_stat(stat);

  GCNotificationRequest *request = new GCNotificationRequest(os::javaTimeMillis(),mgr,action,cause,stat);

  addRequest(request);

 }

void GCNotifier::addRequest(GCNotificationRequest *request) {

  MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);

  if(first_request == NULL) {

    first_request = request;

  } else {

    last_request->next = request;

  }

  last_request = request;

  Service_lock->notify_all();

}

GCNotificationRequest *GCNotifier::getRequest() {

  MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);

  GCNotificationRequest *request = first_request;

  if(first_request != NULL) {

    first_request = first_request->next;

  }

  return request;

}

bool GCNotifier::has_event() {

  return first_request != NULL;

}

static Handle getGcInfoBuilder(GCMemoryManager *gcManager,TRAPS) {

  Klass* gcMBeanKlass = Management::com_sun_management_internal_GarbageCollectorExtImpl_klass(CHECK_NH);

  instanceOop i = gcManager->get_memory_manager_instance(THREAD);

  instanceHandle ih(THREAD, i);

  JavaValue result(T_OBJECT);

  JavaCallArguments args(ih);

  JavaCalls::call_virtual(&result,

                          gcMBeanKlass,

                          vmSymbols::getGcInfoBuilder_name(),

                          vmSymbols::getGcInfoBuilder_signature(),

                          &args,

                          CHECK_NH);

  return Handle(THREAD,(oop)result.get_jobject());

}

static Handle createGcInfo(GCMemoryManager *gcManager, GCStatInfo *gcStatInfo,TRAPS) {

  // Fill the arrays of MemoryUsage objects with before and after GC

  // per pool memory usage

  InstanceKlass* mu_klass = Management::java_lang_management_MemoryUsage_klass(CHECK_NH);

  // The array allocations below should use a handle containing mu_klass

  // as the first allocation could trigger a GC, causing the actual

  // klass oop to move, and leaving mu_klass pointing to the old

  // location.

  objArrayOop bu = oopFactory::new_objArray(mu_klass, MemoryService::num_memory_pools(), CHECK_NH);

  objArrayHandle usage_before_gc_ah(THREAD, bu);

  objArrayOop au = oopFactory::new_objArray(mu_klass, MemoryService::num_memory_pools(), CHECK_NH);

  objArrayHandle usage_after_gc_ah(THREAD, au);

  for (int i = 0; i < MemoryService::num_memory_pools(); i++) {

    Handle before_usage = MemoryService::create_MemoryUsage_obj(gcStatInfo->before_gc_usage_for_pool(i), CHECK_NH);

    Handle after_usage;

    MemoryUsage u = gcStatInfo->after_gc_usage_for_pool(i);

    if (u.max_size() == 0 && u.used() > 0) {

      // If max size == 0, this pool is a survivor space.

      // Set max size = -1 since the pools will be swapped after GC.

      MemoryUsage usage(u.init_size(), u.used(), u.committed(), (size_t)-1);

      after_usage = MemoryService::create_MemoryUsage_obj(usage, CHECK_NH);

    } else {

        after_usage = MemoryService::create_MemoryUsage_obj(u, CHECK_NH);

    }

    usage_before_gc_ah->obj_at_put(i, before_usage());

    usage_after_gc_ah->obj_at_put(i, after_usage());

  }

  // Current implementation only has 1 attribute (number of GC threads)

  // The type is 'I'

  objArrayOop extra_args_array = oopFactory::new_objArray(SystemDictionary::Integer_klass(), 1, CHECK_NH);

  objArrayHandle extra_array (THREAD, extra_args_array);

  InstanceKlass* intK = SystemDictionary::Integer_klass();

  instanceHandle extra_arg_val = intK->allocate_instance_handle(CHECK_NH);

  {

    JavaValue res(T_VOID);

    JavaCallArguments argsInt;

    argsInt.push_oop(extra_arg_val);

    argsInt.push_int(gcManager->num_gc_threads());

    JavaCalls::call_special(&res,

                            intK,

                            vmSymbols::object_initializer_name(),

                            vmSymbols::int_void_signature(),

                            &argsInt,

                            CHECK_NH);

  }

  extra_array->obj_at_put(0,extra_arg_val());

  InstanceKlass* gcInfoklass = Management::com_sun_management_GcInfo_klass(CHECK_NH);

  Handle gcInfo_instance = gcInfoklass->allocate_instance_handle(CHECK_NH);

  JavaValue constructor_result(T_VOID);

  JavaCallArguments constructor_args(16);

  constructor_args.push_oop(gcInfo_instance);

  constructor_args.push_oop(getGcInfoBuilder(gcManager,THREAD));

  constructor_args.push_long(gcStatInfo->gc_index());

  constructor_args.push_long(Management::ticks_to_ms(gcStatInfo->start_time()));

  constructor_args.push_long(Management::ticks_to_ms(gcStatInfo->end_time()));

  constructor_args.push_oop(usage_before_gc_ah);

  constructor_args.push_oop(usage_after_gc_ah);

  constructor_args.push_oop(extra_array);

  JavaCalls::call_special(&constructor_result,

                          gcInfoklass,

                          vmSymbols::object_initializer_name(),

                          vmSymbols::com_sun_management_GcInfo_constructor_signature(),

                          &constructor_args,

                          CHECK_NH);

  return Handle(THREAD, gcInfo_instance());

}

void GCNotifier::sendNotification(TRAPS) {

  GCNotifier::sendNotificationInternal(THREAD);

  // Clearing pending exception to avoid premature termination of

  // the service thread

  if (HAS_PENDING_EXCEPTION) {

    CLEAR_PENDING_EXCEPTION;

  }

}

class NotificationMark : public StackObj {

  // This class is used in GCNotifier::sendNotificationInternal to ensure that

  // the GCNotificationRequest object is properly cleaned up, whatever path

  // is used to exit the method.

  GCNotificationRequest* _request;

public:

  NotificationMark(GCNotificationRequest* r) {

    _request = r;

  }

  ~NotificationMark() {

    assert(_request != NULL, "Sanity check");

    delete _request;

  }

};

void GCNotifier::sendNotificationInternal(TRAPS) {

  ResourceMark rm(THREAD);

  HandleMark hm(THREAD);

  GCNotificationRequest *request = getRequest();

  if (request != NULL) {

    NotificationMark nm(request);

    Handle objGcInfo = createGcInfo(request->gcManager, request->gcStatInfo, CHECK);

    Handle objName = java_lang_String::create_from_str(request->gcManager->name(), CHECK);

    Handle objAction = java_lang_String::create_from_str(request->gcAction, CHECK);

    Handle objCause = java_lang_String::create_from_str(request->gcCause, CHECK);

    InstanceKlass* gc_mbean_klass = Management::com_sun_management_internal_GarbageCollectorExtImpl_klass(CHECK);

    instanceOop gc_mbean = request->gcManager->get_memory_manager_instance(THREAD);

    instanceHandle gc_mbean_h(THREAD, gc_mbean);

    if (!gc_mbean_h->is_a(gc_mbean_klass)) {

      THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(),

                "This GCMemoryManager doesn't have a GarbageCollectorMXBean");

    }

    JavaValue result(T_VOID);

    JavaCallArguments args(gc_mbean_h);

    args.push_long(request->timestamp);

    args.push_oop(objName);

    args.push_oop(objAction);

    args.push_oop(objCause);

    args.push_oop(objGcInfo);

    JavaCalls::call_virtual(&result,

                            gc_mbean_klass,

                            vmSymbols::createGCNotification_name(),

                            vmSymbols::createGCNotification_signature(),

                            &args,

                            CHECK);

  }

}