178 lines
4.9 KiB
TypeScript
178 lines
4.9 KiB
TypeScript
// Copyright 2018-2022 the oak authors. All rights reserved. MIT license.
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export type StructuredClonable =
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| { [key: string]: StructuredClonable }
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| Array<StructuredClonable>
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| ArrayBuffer
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| ArrayBufferView
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// deno-lint-ignore ban-types
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| BigInt
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| bigint
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| Blob
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// deno-lint-ignore ban-types
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| Boolean
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| boolean
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| Date
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| Error
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| EvalError
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| Map<StructuredClonable, StructuredClonable>
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// deno-lint-ignore ban-types
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| Number
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| number
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| RangeError
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| ReferenceError
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| RegExp
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| Set<StructuredClonable>
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// deno-lint-ignore ban-types
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| String
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| string
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| SyntaxError
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| TypeError
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| URIError;
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/** Internal functions on the `Deno.core` namespace */
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interface DenoCore {
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deserialize(value: unknown): StructuredClonable;
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serialize(value: StructuredClonable): unknown;
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}
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const objectCloneMemo = new WeakMap();
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function cloneArrayBuffer(
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srcBuffer: ArrayBuffer,
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srcByteOffset: number,
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srcLength: number,
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// deno-lint-ignore no-explicit-any
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_cloneConstructor: any,
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) {
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// this function fudges the return type but SharedArrayBuffer is disabled for a while anyway
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return srcBuffer.slice(
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srcByteOffset,
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srcByteOffset + srcLength,
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);
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}
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/** A loose approximation for structured cloning, used when the `Deno.core`
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* APIs are not available. */
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// deno-lint-ignore no-explicit-any
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function cloneValue(value: any): any {
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switch (typeof value) {
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case "number":
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case "string":
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case "boolean":
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case "undefined":
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case "bigint":
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return value;
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case "object": {
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if (objectCloneMemo.has(value)) {
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return objectCloneMemo.get(value);
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}
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if (value === null) {
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return value;
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}
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if (value instanceof Date) {
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return new Date(value.valueOf());
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}
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if (value instanceof RegExp) {
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return new RegExp(value);
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}
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if (value instanceof SharedArrayBuffer) {
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return value;
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}
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if (value instanceof ArrayBuffer) {
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const cloned = cloneArrayBuffer(
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value,
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0,
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value.byteLength,
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ArrayBuffer,
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);
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objectCloneMemo.set(value, cloned);
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return cloned;
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}
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if (ArrayBuffer.isView(value)) {
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const clonedBuffer = cloneValue(value.buffer);
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// Use DataViewConstructor type purely for type-checking, can be a
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// DataView or TypedArray. They use the same constructor signature,
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// only DataView has a length in bytes and TypedArrays use a length in
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// terms of elements, so we adjust for that.
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let length;
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if (value instanceof DataView) {
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length = value.byteLength;
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} else {
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// deno-lint-ignore no-explicit-any
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length = (value as any).length;
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}
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// deno-lint-ignore no-explicit-any
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return new (value.constructor as any)(
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clonedBuffer,
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value.byteOffset,
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length,
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);
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}
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if (value instanceof Map) {
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const clonedMap = new Map();
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objectCloneMemo.set(value, clonedMap);
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value.forEach((v, k) => {
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clonedMap.set(cloneValue(k), cloneValue(v));
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});
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return clonedMap;
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}
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if (value instanceof Set) {
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// assumes that cloneValue still takes only one argument
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const clonedSet = new Set([...value].map(cloneValue));
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objectCloneMemo.set(value, clonedSet);
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return clonedSet;
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}
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// default for objects
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// deno-lint-ignore no-explicit-any
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const clonedObj: Record<any, any> = {};
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objectCloneMemo.set(value, clonedObj);
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const sourceKeys = Object.getOwnPropertyNames(value);
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for (const key of sourceKeys) {
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clonedObj[key] = cloneValue(value[key]);
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}
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Reflect.setPrototypeOf(clonedObj, Reflect.getPrototypeOf(value));
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return clonedObj;
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}
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case "symbol":
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case "function":
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default:
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throw new DOMException("Uncloneable value in stream", "DataCloneError");
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}
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}
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// deno-lint-ignore no-explicit-any
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const core = (Deno as any)?.core as DenoCore | undefined;
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const structuredClone: ((value: unknown) => unknown) | undefined =
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// deno-lint-ignore no-explicit-any
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(globalThis as any).structuredClone;
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/**
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* Provides structured cloning
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* @param value
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* @returns
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*/
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function sc<T extends StructuredClonable>(value: T): T {
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return structuredClone
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? structuredClone(value)
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: core
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? core.deserialize(core.serialize(value))
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: cloneValue(value);
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}
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/** Clones a state object, skipping any values that cannot be cloned. */
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// deno-lint-ignore no-explicit-any
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export function cloneState<S extends Record<string, any>>(state: S): S {
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const clone = {} as S;
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for (const [key, value] of Object.entries(state)) {
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try {
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const clonedValue = sc(value);
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clone[key as keyof S] = clonedValue;
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} catch {
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// we just no-op values that cannot be cloned
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}
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}
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return clone;
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}
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