/*

 * Copyright (c) 2014, 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

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

 * questions.

 *

 */

#include "precompiled.hpp"

#include "jfr/leakprofiler/emitEventOperation.hpp"

#include "jfr/leakprofiler/leakProfiler.hpp"

#include "jfr/leakprofiler/startOperation.hpp"

#include "jfr/leakprofiler/stopOperation.hpp"

#include "jfr/leakprofiler/sampling/objectSampler.hpp"

#include "jfr/recorder/service/jfrOptionSet.hpp"

#include "memory/iterator.hpp"

#include "oops/oop.hpp"

#include "runtime/atomic.hpp"

#include "runtime/orderAccess.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/vmThread.hpp"

#include "utilities/ostream.hpp"

// Only to be updated during safepoint

ObjectSampler* LeakProfiler::_object_sampler = NULL;

static volatile jbyte suspended = 0;

bool LeakProfiler::start(jint sample_count) {

  if (UseZGC) {

    log_warning(jfr)("LeakProfiler is currently not supported in combination with ZGC");

    return false;

  }

  if (_object_sampler != NULL) {

    // already started

    return true;

  }

  // Allows user to disable leak profiler on command line by setting queue size to zero.

  if (sample_count > 0) {

    StartOperation op(sample_count);

    VMThread::execute(&op);

    return _object_sampler != NULL;

  }

  return false;

}

bool LeakProfiler::stop() {

  if (_object_sampler == NULL) {

    // already stopped/not started

    return true;

  }

  StopOperation op;

  VMThread::execute(&op);

  return _object_sampler == NULL;

}

void LeakProfiler::emit_events(jlong cutoff_ticks, bool emit_all) {

  if (!is_running()) {

    return;

  }

  EmitEventOperation op(cutoff_ticks, emit_all);

  VMThread::execute(&op);

}

void LeakProfiler::oops_do(BoolObjectClosure* is_alive, OopClosure* f) {

  assert(SafepointSynchronize::is_at_safepoint(),

    "Leak Profiler::oops_do(...) may only be called during safepoint");

  if (_object_sampler != NULL) {

    _object_sampler->oops_do(is_alive, f);

  }

}

void LeakProfiler::sample(HeapWord* object,

                          size_t size,

                          JavaThread* thread) {

  assert(is_running(), "invariant");

  assert(thread != NULL, "invariant");

  assert(thread->thread_state() == _thread_in_vm, "invariant");

  // exclude compiler threads and code sweeper thread

  if (thread->is_hidden_from_external_view()) {

    return;

  }

  _object_sampler->add(object, size, thread);

}

ObjectSampler* LeakProfiler::object_sampler() {

  assert(is_suspended() || SafepointSynchronize::is_at_safepoint(),

    "Leak Profiler::object_sampler() may only be called during safepoint");

  return _object_sampler;

}

void LeakProfiler::set_object_sampler(ObjectSampler* object_sampler) {

  assert(SafepointSynchronize::is_at_safepoint(),

    "Leak Profiler::set_object_sampler() may only be called during safepoint");

  _object_sampler = object_sampler;

}

bool LeakProfiler::is_running() {

  return _object_sampler != NULL && !suspended;

}

bool LeakProfiler::is_suspended() {

  return _object_sampler != NULL && suspended;

}

void LeakProfiler::resume() {

  assert(is_suspended(), "invariant");

  OrderAccess::storestore();

  Atomic::store((jbyte)0, &suspended);

  assert(is_running(), "invariant");

}

void LeakProfiler::suspend() {

  assert(SafepointSynchronize::is_at_safepoint(), "invariant");

  assert(_object_sampler != NULL, "invariant");

  assert(!is_suspended(), "invariant");

  suspended = (jbyte)1; // safepoint visible

}