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denoland-deno/ext/web/02_structured_clone.js

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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// @ts-check
/// <reference path="../../core/lib.deno_core.d.ts" />
/// <reference path="../../core/internal.d.ts" />
/// <reference path="../web/internal.d.ts" />
/// <reference path="../web/lib.deno_web.d.ts" />
import { core, primordials } from "ext:core/mod.js";
const {
isArrayBuffer,
} = core;
const {
ArrayBuffer,
ArrayBufferPrototypeGetByteLength,
ArrayBufferPrototypeSlice,
ArrayBufferIsView,
DataView,
DataViewPrototypeGetBuffer,
DataViewPrototypeGetByteLength,
DataViewPrototypeGetByteOffset,
ObjectPrototypeIsPrototypeOf,
SafeWeakMap,
TypedArrayPrototypeGetBuffer,
TypedArrayPrototypeGetByteOffset,
TypedArrayPrototypeGetLength,
TypedArrayPrototypeGetSymbolToStringTag,
TypeErrorPrototype,
WeakMapPrototypeSet,
Int8Array,
Int16Array,
Int32Array,
BigInt64Array,
Uint8Array,
Uint8ClampedArray,
Uint16Array,
Uint32Array,
BigUint64Array,
Float32Array,
Float64Array,
} = primordials;
import { DOMException } from "./01_dom_exception.js";
const objectCloneMemo = new SafeWeakMap();
function cloneArrayBuffer(
srcBuffer,
srcByteOffset,
srcLength,
_cloneConstructor,
) {
// this function fudges the return type but SharedArrayBuffer is disabled for a while anyway
return ArrayBufferPrototypeSlice(
srcBuffer,
srcByteOffset,
srcByteOffset + srcLength,
);
}
// TODO(petamoriken): add Resizable ArrayBuffer support
/** Clone a value in a similar way to structured cloning. It is similar to a
* StructureDeserialize(StructuredSerialize(...)). */
function structuredClone(value) {
// Performance optimization for buffers, otherwise
// `serialize/deserialize` will allocate new buffer.
if (isArrayBuffer(value)) {
const cloned = cloneArrayBuffer(
value,
0,
ArrayBufferPrototypeGetByteLength(value),
ArrayBuffer,
);
WeakMapPrototypeSet(objectCloneMemo, value, cloned);
return cloned;
}
if (ArrayBufferIsView(value)) {
const tag = TypedArrayPrototypeGetSymbolToStringTag(value);
// DataView
if (tag === undefined) {
return new DataView(
structuredClone(DataViewPrototypeGetBuffer(value)),
DataViewPrototypeGetByteOffset(value),
DataViewPrototypeGetByteLength(value),
);
}
// TypedArray
let Constructor;
switch (tag) {
case "Int8Array":
Constructor = Int8Array;
break;
case "Int16Array":
Constructor = Int16Array;
break;
case "Int32Array":
Constructor = Int32Array;
break;
case "BigInt64Array":
Constructor = BigInt64Array;
break;
case "Uint8Array":
Constructor = Uint8Array;
break;
case "Uint8ClampedArray":
Constructor = Uint8ClampedArray;
break;
case "Uint16Array":
Constructor = Uint16Array;
break;
case "Uint32Array":
Constructor = Uint32Array;
break;
case "BigUint64Array":
Constructor = BigUint64Array;
break;
case "Float16Array":
// TODO(petamoriken): add Float16Array to primordials
Constructor = Float16Array;
break;
case "Float32Array":
Constructor = Float32Array;
break;
case "Float64Array":
Constructor = Float64Array;
break;
}
return new Constructor(
structuredClone(TypedArrayPrototypeGetBuffer(value)),
TypedArrayPrototypeGetByteOffset(value),
TypedArrayPrototypeGetLength(value),
);
}
try {
return core.deserialize(core.serialize(value));
} catch (e) {
if (ObjectPrototypeIsPrototypeOf(TypeErrorPrototype, e)) {
throw new DOMException(e.message, "DataCloneError");
}
throw e;
}
}
export { structuredClone };