/*

 * Copyright (c) Meta Platforms, Inc. and affiliates.

 *

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

 */

#include "hermes/VM/AlignedStorage.h"

#include "hermes/Support/OSCompat.h"

#include "hermes/VM/StorageProvider.h"

#include <cassert>

#include <utility>

namespace hermes {

namespace vm {

void swap(AlignedStorage &a, AlignedStorage &b) {

  using std::swap;

  swap(a.lowLim_, b.lowLim_);

  swap(a.provider_, b.provider_);

}

llvh::ErrorOr<AlignedStorage> AlignedStorage::create(

    StorageProvider *provider) {

  return create(provider, nullptr);

}

llvh::ErrorOr<AlignedStorage> AlignedStorage::create(

    StorageProvider *provider,

    const char *name) {

  auto result = provider->newStorage(name);

  if (!result) {

    return result.getError();

  }

  return AlignedStorage{provider, *result};

}

AlignedStorage::AlignedStorage(StorageProvider *provider, void *lowLim)

    : lowLim_(static_cast<char *>(lowLim)), provider_(provider) {

  assert(

      AlignedStorage::start(lowLim_) == lowLim_ &&

      "The lower limit of this storage must be aligned");

}

AlignedStorage::AlignedStorage(AlignedStorage &&that) : AlignedStorage() {

  swap(*this, that);

  assert(

      AlignedStorage::start(lowLim_) == lowLim_ &&

      "The lower limit of this storage must be aligned");

}

AlignedStorage &AlignedStorage::operator=(AlignedStorage that) {

  swap(*this, that);

  assert(

      AlignedStorage::start(lowLim_) == lowLim_ &&

      "The lower limit of this storage must be aligned");

  return *this;

}

AlignedStorage::~AlignedStorage() {

  if (provider_) {

    provider_->deleteStorage(lowLim_);

  }

}

void AlignedStorage::markUnused(char *from, char *to) {

  assert(from <= to && "Unused region boundaries inverted");

  assert(lowLim() <= from && to <= hiLim() && "Unused region out-of-bounds");

#ifndef HERMESVM_ALLOW_HUGE_PAGES

  oscompat::vm_unused(from, to - from);

#endif

}

} // namespace vm

} // namespace hermes