external-entity-table.h | Explore in Territory

// Copyright 2022 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_SANDBOX_EXTERNAL_ENTITY_TABLE_H_
#define V8_SANDBOX_EXTERNAL_ENTITY_TABLE_H_

#include <set>

#include "include/v8-platform.h"
#include "include/v8config.h"
#include "src/base/atomicops.h"
#include "src/base/memory.h"
#include "src/base/platform/mutex.h"
#include "src/common/code-memory-access.h"
#include "src/common/globals.h"
#include "src/common/segmented-table.h"

#ifdef V8_COMPRESS_POINTERS

namespace v8 {
namespace internal {

class Isolate;

/**
 * A thread-safe table with a fixed maximum size for storing references to
 * objects located outside of the sandbox.
 *
 * An external entity table provides the basic mechanisms to ensure
 * safe access to objects located outside the sandbox, but referenced
 * from within it. When an external entity table is used, objects located
 * inside the sandbox reference outside objects through indices into the table.
 *
 * The ExternalEntityTable class should be seen an an incomplete class that
 * needs to be extended by a concrete implementation class, such as the
 * ExternalPointerTable class, as it is lacking some functionality. In
 * particular, while the ExternalEntityTable implements basic table memory
 * management as well as entry allocation routines, it does not implement any
 * logic for reclaiming entries such as garbage collection. This must be done
 * by the child classes.
 *
 * For the purpose of memory management, the table is partitioned into Segments
 * (for example 64kb memory chunks) that are grouped together in "Spaces". All
 * segments in a space share a freelist, and so entry allocation and garbage
 * collection happen on the level of spaces.
 */
template <typename Entry, size_t size>
class V8_EXPORT_PRIVATE ExternalEntityTable
    : public SegmentedTable<Entry, size> { … };

}  // namespace internal
}  // namespace v8

#endif  // V8_COMPRESS_POINTERS

#endif  // V8_SANDBOX_EXTERNAL_ENTITY_TABLE_H_
chromium/v8/src/sandbox/external-entity-table.h
