/*

 * Copyright (c) 2017, 2019, 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 "memory/metaspaceClosure.hpp"

// Update the reference to point to new_loc.

void MetaspaceClosure::Ref::update(address new_loc) const {

  log_trace(cds)("Ref: [" PTR_FORMAT "] -> " PTR_FORMAT " => " PTR_FORMAT,

                 p2i(mpp()), p2i(obj()), p2i(new_loc));

  uintx p = (uintx)new_loc;

  p |= flag_bits(); // Make sure the flag bits are copied to the new pointer.

  *(address*)mpp() = (address)p;

}

void MetaspaceClosure::push_impl(MetaspaceClosure::Ref* ref) {

  if (_nest_level < MAX_NEST_LEVEL) {

    do_push(ref);

    delete ref;

  } else {

    ref->set_next(_pending_refs);

    _pending_refs = ref;

  }

}

void MetaspaceClosure::do_push(MetaspaceClosure::Ref* ref) {

  if (ref->not_null()) {

    bool read_only;

    Writability w = ref->writability();

    switch (w) {

    case _writable:

      read_only = false;

      break;

    case _not_writable:

      read_only = true;

      break;

    default:

      assert(w == _default, "must be");

      read_only = ref->is_read_only_by_default();

    }

    _nest_level ++;

    if (do_ref(ref, read_only)) { // true means we want to iterate the embedded pointer in <ref>

      ref->metaspace_pointers_do(this);

    }

    _nest_level --;

  }

}

void MetaspaceClosure::finish() {

  assert(_nest_level == 0, "must be");

  while (_pending_refs != NULL) {

    Ref* ref = _pending_refs;

    _pending_refs = _pending_refs->next();

    do_push(ref);

    delete ref;

  }

}

MetaspaceClosure::~MetaspaceClosure() {

  assert(_pending_refs == NULL,

         "you must explicitly call MetaspaceClosure::finish() to process all refs!");

}

bool UniqueMetaspaceClosure::do_ref(MetaspaceClosure::Ref* ref, bool read_only) {

  bool* found = _has_been_visited.lookup(ref->obj());

  if (found != NULL) {

    assert(*found == read_only, "must be");

    return false; // Already visited: no need to iterate embedded pointers.

  } else {

    _has_been_visited.add(ref->obj(), read_only);

    if (_has_been_visited.maybe_grow(MAX_TABLE_SIZE)) {

      log_info(cds, hashtables)("Expanded _has_been_visited table to %d", _has_been_visited.table_size());

    }

    return do_unique_ref(ref, read_only);

  }

}