/*
 * Copyright (c) 2018, 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/metaspace.hpp"
#include "memory/metaspace/chunkManager.hpp"
#include "memory/metaspace/counter.hpp"
#include "memory/metaspace/commitLimiter.hpp"
#include "memory/metaspace/counter.hpp"
#include "memory/metaspace/virtualSpaceList.hpp"
#include "memory/metaspace/virtualSpaceNode.hpp"
#include "runtime/mutexLocker.hpp"


namespace metaspace {

// Create a new, empty, expandable list.
VirtualSpaceList::VirtualSpaceList(const char* name, CommitLimiter* commit_limiter)
  : _name(name),
    _first_node(NULL),
    _current_node(NULL),
    _can_expand(true),
    _commit_limiter(commit_limiter),
    _reserved_words_counter(),
    _committed_words_counter()
{
  // Create the first node right now. Nothing gets committed yet though.
  create_new_node();
}

// Create a new list. The list will contain one node only, which uses the given ReservedSpace.
// It will be not expandable beyond that first node.
VirtualSpaceList::VirtualSpaceList(const char* name, ReservedSpace rs, CommitLimiter* commit_limiter)
: _name(name),
  _first_node(NULL),
  _current_node(NULL),
  _can_expand(false),
  _commit_limiter(commit_limiter),
  _reserved_words_counter(),
  _committed_words_counter()
{
  // Create the first node spanning the existing ReservedSpace. This will be the only node created
  // for this list since we cannot expand.
  VirtualSpaceNode* vsn = VirtualSpaceNode::create_node(rs, _commit_limiter,
                                                        &_reserved_words_counter, &_committed_words_counter);
  assert(vsn != NULL, "node creation failed");
  _first_node = _current_node = vsn;
  _current_node->set_next(NULL);
}

VirtualSpaceList::~VirtualSpaceList() {
  // Note: normally, there is no reason ever to delete a vslist since they are
  // global objects, but for gtests it makes sense to allow this.
  VirtualSpaceNode* vsn = _first_node;
  VirtualSpaceNode* vsn2 = vsn;
  while (vsn != NULL) {
    vsn2 = vsn->next();
    delete vsn;
    vsn = vsn2;
  }
}

// Create a new node and append it to the list. After
// this function, _current_node shall point to a new empty node.
// List must be expandable for this to work.
void VirtualSpaceList::create_new_node() {
  assert(_can_expand, "List is not expandable");
  VirtualSpaceNode* vsn = VirtualSpaceNode::create_node(constants::virtual_space_node_default_size,
                                                        _commit_limiter,
                                                        &_reserved_words_counter, &_committed_words_counter);
  assert(vsn != NULL, "node creation failed");
  vsn->set_next(_first_node);
  _first_node = _current_node = vsn;
}

// Allocate a root chunk from this list.
// Note: this just returns a chunk whose memory is reserved; no memory is committed yet.
// Hence, before using this chunk, it must be committed.
// Also, no limits are checked, since no committing takes place.
Metachunk*  VirtualSpaceList::allocate_root_chunk() {

  assert(_current_node != NULL, "Sanity");

  Metachunk* c = _current_node->allocate_root_chunk();

  if (c == NULL) {

    // The current node is fully used up.

    // Since all allocations from a VirtualSpaceNode happen in root-chunk-size units,
    // we should never have remaining space.
    assert(_current_node->free_words() == 0, "Sanity");

    if (_can_expand) {
      create_new_node();
    } else {
      return NULL; // We cannot expand this list.
    }
  }

  c = _current_node->allocate_root_chunk();

  assert(c != NULL, "This should have worked");

  return c;

}

// Print all nodes in this space list.
void VirtualSpaceList::print_on(outputStream* st, size_t scale) const {
  const VirtualSpaceNode* vsn = _first_node;
  while (vsn != NULL) {
    vsn->print_on(st, scale);
    st->cr();
    vsn = vsn->next();
  }
}

#ifdef ASSERT
void VirtualSpaceList::verify(bool slow) const {
  assert(_current_node != NULL && _first_node != NULL && _name != NULL, "Sanity");

  size_t total_reserved_words = 0;
  size_t total_committed_words = 0;
  const VirtualSpaceNode* vsn = _first_node;
  while (vsn != NULL) {
    vsn->verify(slow);
    total_reserved_words += vsn->word_size();
    total_committed_words += vsn->committed_words();
    vsn = vsn->next();
  }

  _reserved_words_counter.check(total_reserved_words);
  _committed_words_counter.check(total_committed_words);

}
#endif

// Returns true if this pointer is contained in one of our nodes.
bool VirtualSpaceList::contains(const MetaWord* p) const {
  const VirtualSpaceNode* vsn = _first_node;
  while (vsn != NULL) {
    if (vsn->contains(p)) {
      return true;
    }
    vsn = vsn->next();
  }
  return false;
}

VirtualSpaceList* VirtualSpaceList::_vslist_class = NULL;
VirtualSpaceList* VirtualSpaceList::_vslist_nonclass = NULL;

void VirtualSpaceList::set_vslist_class(VirtualSpaceList* vsl) {
  assert(_vslist_class == NULL, "Sanity");
  _vslist_class = vsl;
}

void VirtualSpaceList::set_vslist_nonclass(VirtualSpaceList* vsl) {
  assert(_vslist_nonclass == NULL, "Sanity");
  _vslist_nonclass = vsl;
}

} // namespace metaspace