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diff --git a/deps/v8/include/v8-array-buffer.h b/deps/v8/include/v8-array-buffer.h
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+++ b/deps/v8/include/v8-array-buffer.h
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+// Copyright 2021 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 INCLUDE_V8_ARRAY_BUFFER_H_
+#define INCLUDE_V8_ARRAY_BUFFER_H_
+
+#include <stddef.h>
+
+#include <memory>
+
+#include "v8-local-handle.h"  // NOLINT(build/include_directory)
+#include "v8-object.h"        // NOLINT(build/include_directory)
+#include "v8config.h"         // NOLINT(build/include_directory)
+
+namespace v8 {
+
+class SharedArrayBuffer;
+
+#ifndef V8_ARRAY_BUFFER_INTERNAL_FIELD_COUNT
+// The number of required internal fields can be defined by embedder.
+#define V8_ARRAY_BUFFER_INTERNAL_FIELD_COUNT 2
+#endif
+
+enum class ArrayBufferCreationMode { kInternalized, kExternalized };
+
+/**
+ * A wrapper around the backing store (i.e. the raw memory) of an array buffer.
+ * See a document linked in http://crbug.com/v8/9908 for more information.
+ *
+ * The allocation and destruction of backing stores is generally managed by
+ * V8. Clients should always use standard C++ memory ownership types (i.e.
+ * std::unique_ptr and std::shared_ptr) to manage lifetimes of backing stores
+ * properly, since V8 internal objects may alias backing stores.
+ *
+ * This object does not keep the underlying |ArrayBuffer::Allocator| alive by
+ * default. Use Isolate::CreateParams::array_buffer_allocator_shared when
+ * creating the Isolate to make it hold a reference to the allocator itself.
+ */
+class V8_EXPORT BackingStore : public v8::internal::BackingStoreBase {
+ public:
+  ~BackingStore();
+
+  /**
+   * Return a pointer to the beginning of the memory block for this backing
+   * store. The pointer is only valid as long as this backing store object
+   * lives.
+   */
+  void* Data() const;
+
+  /**
+   * The length (in bytes) of this backing store.
+   */
+  size_t ByteLength() const;
+
+  /**
+   * Indicates whether the backing store was created for an ArrayBuffer or
+   * a SharedArrayBuffer.
+   */
+  bool IsShared() const;
+
+  /**
+   * Prevent implicit instantiation of operator delete with size_t argument.
+   * The size_t argument would be incorrect because ptr points to the
+   * internal BackingStore object.
+   */
+  void operator delete(void* ptr) { ::operator delete(ptr); }
+
+  /**
+   * Wrapper around ArrayBuffer::Allocator::Reallocate that preserves IsShared.
+   * Assumes that the backing_store was allocated by the ArrayBuffer allocator
+   * of the given isolate.
+   */
+  static std::unique_ptr<BackingStore> Reallocate(
+      v8::Isolate* isolate, std::unique_ptr<BackingStore> backing_store,
+      size_t byte_length);
+
+  /**
+   * This callback is used only if the memory block for a BackingStore cannot be
+   * allocated with an ArrayBuffer::Allocator. In such cases the destructor of
+   * the BackingStore invokes the callback to free the memory block.
+   */
+  using DeleterCallback = void (*)(void* data, size_t length,
+                                   void* deleter_data);
+
+  /**
+   * If the memory block of a BackingStore is static or is managed manually,
+   * then this empty deleter along with nullptr deleter_data can be passed to
+   * ArrayBuffer::NewBackingStore to indicate that.
+   *
+   * The manually managed case should be used with caution and only when it
+   * is guaranteed that the memory block freeing happens after detaching its
+   * ArrayBuffer.
+   */
+  static void EmptyDeleter(void* data, size_t length, void* deleter_data);
+
+ private:
+  /**
+   * See [Shared]ArrayBuffer::GetBackingStore and
+   * [Shared]ArrayBuffer::NewBackingStore.
+   */
+  BackingStore();
+};
+
+#if !defined(V8_IMMINENT_DEPRECATION_WARNINGS)
+// Use v8::BackingStore::DeleterCallback instead.
+using BackingStoreDeleterCallback = void (*)(void* data, size_t length,
+                                             void* deleter_data);
+
+#endif
+
+/**
+ * An instance of the built-in ArrayBuffer constructor (ES6 draft 15.13.5).
+ */
+class V8_EXPORT ArrayBuffer : public Object {
+ public:
+  /**
+   * A thread-safe allocator that V8 uses to allocate |ArrayBuffer|'s memory.
+   * The allocator is a global V8 setting. It has to be set via
+   * Isolate::CreateParams.
+   *
+   * Memory allocated through this allocator by V8 is accounted for as external
+   * memory by V8. Note that V8 keeps track of the memory for all internalized
+   * |ArrayBuffer|s. Responsibility for tracking external memory (using
+   * Isolate::AdjustAmountOfExternalAllocatedMemory) is handed over to the
+   * embedder upon externalization and taken over upon internalization (creating
+   * an internalized buffer from an existing buffer).
+   *
+   * Note that it is unsafe to call back into V8 from any of the allocator
+   * functions.
+   */
+  class V8_EXPORT Allocator {
+   public:
+    virtual ~Allocator() = default;
+
+    /**
+     * Allocate |length| bytes. Return nullptr if allocation is not successful.
+     * Memory should be initialized to zeroes.
+     */
+    virtual void* Allocate(size_t length) = 0;
+
+    /**
+     * Allocate |length| bytes. Return nullptr if allocation is not successful.
+     * Memory does not have to be initialized.
+     */
+    virtual void* AllocateUninitialized(size_t length) = 0;
+
+    /**
+     * Free the memory block of size |length|, pointed to by |data|.
+     * That memory is guaranteed to be previously allocated by |Allocate|.
+     */
+    virtual void Free(void* data, size_t length) = 0;
+
+    /**
+     * Reallocate the memory block of size |old_length| to a memory block of
+     * size |new_length| by expanding, contracting, or copying the existing
+     * memory block. If |new_length| > |old_length|, then the new part of
+     * the memory must be initialized to zeros. Return nullptr if reallocation
+     * is not successful.
+     *
+     * The caller guarantees that the memory block was previously allocated
+     * using Allocate or AllocateUninitialized.
+     *
+     * The default implementation allocates a new block and copies data.
+     */
+    virtual void* Reallocate(void* data, size_t old_length, size_t new_length);
+
+    /**
+     * ArrayBuffer allocation mode. kNormal is a malloc/free style allocation,
+     * while kReservation is for larger allocations with the ability to set
+     * access permissions.
+     */
+    enum class AllocationMode { kNormal, kReservation };
+
+    /**
+     * Convenience allocator.
+     *
+     * When the virtual memory cage is enabled, this allocator will allocate its
+     * backing memory inside the cage. Otherwise, it will rely on malloc/free.
+     *
+     * Caller takes ownership, i.e. the returned object needs to be freed using
+     * |delete allocator| once it is no longer in use.
+     */
+    static Allocator* NewDefaultAllocator();
+  };
+
+  /**
+   * Data length in bytes.
+   */
+  size_t ByteLength() const;
+
+  /**
+   * Create a new ArrayBuffer. Allocate |byte_length| bytes.
+   * Allocated memory will be owned by a created ArrayBuffer and
+   * will be deallocated when it is garbage-collected,
+   * unless the object is externalized.
+   */
+  static Local<ArrayBuffer> New(Isolate* isolate, size_t byte_length);
+
+  /**
+   * Create a new ArrayBuffer with an existing backing store.
+   * The created array keeps a reference to the backing store until the array
+   * is garbage collected. Note that the IsExternal bit does not affect this
+   * reference from the array to the backing store.
+   *
+   * In future IsExternal bit will be removed. Until then the bit is set as
+   * follows. If the backing store does not own the underlying buffer, then
+   * the array is created in externalized state. Otherwise, the array is created
+   * in internalized state. In the latter case the array can be transitioned
+   * to the externalized state using Externalize(backing_store).
+   */
+  static Local<ArrayBuffer> New(Isolate* isolate,
+                                std::shared_ptr<BackingStore> backing_store);
+
+  /**
+   * Returns a new standalone BackingStore that is allocated using the array
+   * buffer allocator of the isolate. The result can be later passed to
+   * ArrayBuffer::New.
+   *
+   * If the allocator returns nullptr, then the function may cause GCs in the
+   * given isolate and re-try the allocation. If GCs do not help, then the
+   * function will crash with an out-of-memory error.
+   */
+  static std::unique_ptr<BackingStore> NewBackingStore(Isolate* isolate,
+                                                       size_t byte_length);
+  /**
+   * Returns a new standalone BackingStore that takes over the ownership of
+   * the given buffer. The destructor of the BackingStore invokes the given
+   * deleter callback.
+   *
+   * The result can be later passed to ArrayBuffer::New. The raw pointer
+   * to the buffer must not be passed again to any V8 API function.
+   */
+  static std::unique_ptr<BackingStore> NewBackingStore(
+      void* data, size_t byte_length, v8::BackingStore::DeleterCallback deleter,
+      void* deleter_data);
+
+  /**
+   * Returns true if this ArrayBuffer may be detached.
+   */
+  bool IsDetachable() const;
+
+  /**
+   * Detaches this ArrayBuffer and all its views (typed arrays).
+   * Detaching sets the byte length of the buffer and all typed arrays to zero,
+   * preventing JavaScript from ever accessing underlying backing store.
+   * ArrayBuffer should have been externalized and must be detachable.
+   */
+  void Detach();
+
+  /**
+   * Get a shared pointer to the backing store of this array buffer. This
+   * pointer coordinates the lifetime management of the internal storage
+   * with any live ArrayBuffers on the heap, even across isolates. The embedder
+   * should not attempt to manage lifetime of the storage through other means.
+   */
+  std::shared_ptr<BackingStore> GetBackingStore();
+
+  V8_INLINE static ArrayBuffer* Cast(Value* value) {
+#ifdef V8_ENABLE_CHECKS
+    CheckCast(value);
+#endif
+    return static_cast<ArrayBuffer*>(value);
+  }
+
+  static const int kInternalFieldCount = V8_ARRAY_BUFFER_INTERNAL_FIELD_COUNT;
+  static const int kEmbedderFieldCount = V8_ARRAY_BUFFER_INTERNAL_FIELD_COUNT;
+
+ private:
+  ArrayBuffer();
+  static void CheckCast(Value* obj);
+};
+
+#ifndef V8_ARRAY_BUFFER_VIEW_INTERNAL_FIELD_COUNT
+// The number of required internal fields can be defined by embedder.
+#define V8_ARRAY_BUFFER_VIEW_INTERNAL_FIELD_COUNT 2
+#endif
+
+/**
+ * A base class for an instance of one of "views" over ArrayBuffer,
+ * including TypedArrays and DataView (ES6 draft 15.13).
+ */
+class V8_EXPORT ArrayBufferView : public Object {
+ public:
+  /**
+   * Returns underlying ArrayBuffer.
+   */
+  Local<ArrayBuffer> Buffer();
+  /**
+   * Byte offset in |Buffer|.
+   */
+  size_t ByteOffset();
+  /**
+   * Size of a view in bytes.
+   */
+  size_t ByteLength();
+
+  /**
+   * Copy the contents of the ArrayBufferView's buffer to an embedder defined
+   * memory without additional overhead that calling ArrayBufferView::Buffer
+   * might incur.
+   *
+   * Will write at most min(|byte_length|, ByteLength) bytes starting at
+   * ByteOffset of the underlying buffer to the memory starting at |dest|.
+   * Returns the number of bytes actually written.
+   */
+  size_t CopyContents(void* dest, size_t byte_length);
+
+  /**
+   * Returns true if ArrayBufferView's backing ArrayBuffer has already been
+   * allocated.
+   */
+  bool HasBuffer() const;
+
+  V8_INLINE static ArrayBufferView* Cast(Value* value) {
+#ifdef V8_ENABLE_CHECKS
+    CheckCast(value);
+#endif
+    return static_cast<ArrayBufferView*>(value);
+  }
+
+  static const int kInternalFieldCount =
+      V8_ARRAY_BUFFER_VIEW_INTERNAL_FIELD_COUNT;
+  static const int kEmbedderFieldCount =
+      V8_ARRAY_BUFFER_VIEW_INTERNAL_FIELD_COUNT;
+
+ private:
+  ArrayBufferView();
+  static void CheckCast(Value* obj);
+};
+
+/**
+ * An instance of DataView constructor (ES6 draft 15.13.7).
+ */
+class V8_EXPORT DataView : public ArrayBufferView {
+ public:
+  static Local<DataView> New(Local<ArrayBuffer> array_buffer,
+                             size_t byte_offset, size_t length);
+  static Local<DataView> New(Local<SharedArrayBuffer> shared_array_buffer,
+                             size_t byte_offset, size_t length);
+  V8_INLINE static DataView* Cast(Value* value) {
+#ifdef V8_ENABLE_CHECKS
+    CheckCast(value);
+#endif
+    return static_cast<DataView*>(value);
+  }
+
+ private:
+  DataView();
+  static void CheckCast(Value* obj);
+};
+
+/**
+ * An instance of the built-in SharedArrayBuffer constructor.
+ */
+class V8_EXPORT SharedArrayBuffer : public Object {
+ public:
+  /**
+   * Data length in bytes.
+   */
+  size_t ByteLength() const;
+
+  /**
+   * Create a new SharedArrayBuffer. Allocate |byte_length| bytes.
+   * Allocated memory will be owned by a created SharedArrayBuffer and
+   * will be deallocated when it is garbage-collected,
+   * unless the object is externalized.
+   */
+  static Local<SharedArrayBuffer> New(Isolate* isolate, size_t byte_length);
+
+  /**
+   * Create a new SharedArrayBuffer with an existing backing store.
+   * The created array keeps a reference to the backing store until the array
+   * is garbage collected. Note that the IsExternal bit does not affect this
+   * reference from the array to the backing store.
+   *
+   * In future IsExternal bit will be removed. Until then the bit is set as
+   * follows. If the backing store does not own the underlying buffer, then
+   * the array is created in externalized state. Otherwise, the array is created
+   * in internalized state. In the latter case the array can be transitioned
+   * to the externalized state using Externalize(backing_store).
+   */
+  static Local<SharedArrayBuffer> New(
+      Isolate* isolate, std::shared_ptr<BackingStore> backing_store);
+
+  /**
+   * Returns a new standalone BackingStore that is allocated using the array
+   * buffer allocator of the isolate. The result can be later passed to
+   * SharedArrayBuffer::New.
+   *
+   * If the allocator returns nullptr, then the function may cause GCs in the
+   * given isolate and re-try the allocation. If GCs do not help, then the
+   * function will crash with an out-of-memory error.
+   */
+  static std::unique_ptr<BackingStore> NewBackingStore(Isolate* isolate,
+                                                       size_t byte_length);
+  /**
+   * Returns a new standalone BackingStore that takes over the ownership of
+   * the given buffer. The destructor of the BackingStore invokes the given
+   * deleter callback.
+   *
+   * The result can be later passed to SharedArrayBuffer::New. The raw pointer
+   * to the buffer must not be passed again to any V8 functions.
+   */
+  static std::unique_ptr<BackingStore> NewBackingStore(
+      void* data, size_t byte_length, v8::BackingStore::DeleterCallback deleter,
+      void* deleter_data);
+
+  /**
+   * Get a shared pointer to the backing store of this array buffer. This
+   * pointer coordinates the lifetime management of the internal storage
+   * with any live ArrayBuffers on the heap, even across isolates. The embedder
+   * should not attempt to manage lifetime of the storage through other means.
+   */
+  std::shared_ptr<BackingStore> GetBackingStore();
+
+  V8_INLINE static SharedArrayBuffer* Cast(Value* value) {
+#ifdef V8_ENABLE_CHECKS
+    CheckCast(value);
+#endif
+    return static_cast<SharedArrayBuffer*>(value);
+  }
+
+  static const int kInternalFieldCount = V8_ARRAY_BUFFER_INTERNAL_FIELD_COUNT;
+
+ private:
+  SharedArrayBuffer();
+  static void CheckCast(Value* obj);
+};
+
+}  // namespace v8
+
+#endif  // INCLUDE_V8_ARRAY_BUFFER_H_