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denoland-deno/cli/js/web/streams/transform-internals.ts
2020-03-05 18:48:55 +01:00

371 lines
14 KiB
TypeScript

// TODO reenable this code when we enable writableStreams and transport types
// // Forked from https://github.com/stardazed/sd-streams/tree/8928cf04b035fd02fb1340b7eb541c76be37e546
// // Copyright (c) 2018-Present by Arthur Langereis - @zenmumbler MIT
// /**
// * streams/transform-internals - internal types and functions for transform streams
// * Part of Stardazed
// * (c) 2018-Present by Arthur Langereis - @zenmumbler
// * https://github.com/stardazed/sd-streams
// */
// /* eslint-disable @typescript-eslint/no-explicit-any */
// // TODO reenable this lint here
// import * as rs from "./readable-internals.ts";
// import * as ws from "./writable-internals.ts";
// import * as shared from "./shared-internals.ts";
// import { createReadableStream } from "./readable-stream.ts";
// import { createWritableStream } from "./writable-stream.ts";
// import { QueuingStrategy, QueuingStrategySizeCallback } from "../dom_types.ts";
// export const state_ = Symbol("transformState_");
// export const backpressure_ = Symbol("backpressure_");
// export const backpressureChangePromise_ = Symbol("backpressureChangePromise_");
// export const readable_ = Symbol("readable_");
// export const transformStreamController_ = Symbol("transformStreamController_");
// export const writable_ = Symbol("writable_");
// export const controlledTransformStream_ = Symbol("controlledTransformStream_");
// export const flushAlgorithm_ = Symbol("flushAlgorithm_");
// export const transformAlgorithm_ = Symbol("transformAlgorithm_");
// // ----
// export type TransformFunction<InputType, OutputType> = (
// chunk: InputType,
// controller: TransformStreamDefaultController<InputType, OutputType>
// ) => void | PromiseLike<void>;
// export type TransformAlgorithm<InputType> = (chunk: InputType) => Promise<void>;
// export type FlushFunction<InputType, OutputType> = (
// controller: TransformStreamDefaultController<InputType, OutputType>
// ) => void | PromiseLike<void>;
// export type FlushAlgorithm = () => Promise<void>;
// // ----
// export interface TransformStreamDefaultController<InputType, OutputType> {
// readonly desiredSize: number | null;
// enqueue(chunk: OutputType): void;
// error(reason: shared.ErrorResult): void;
// terminate(): void;
// [controlledTransformStream_]: TransformStream<InputType, OutputType>; // The TransformStream instance controlled; also used for the IsTransformStreamDefaultController brand check
// [flushAlgorithm_]: FlushAlgorithm; // A promise - returning algorithm which communicates a requested close to the transformer
// [transformAlgorithm_]: TransformAlgorithm<InputType>; // A promise - returning algorithm, taking one argument(the chunk to transform), which requests the transformer perform its transformation
// }
// export interface Transformer<InputType, OutputType> {
// start?(
// controller: TransformStreamDefaultController<InputType, OutputType>
// ): void | PromiseLike<void>;
// transform?: TransformFunction<InputType, OutputType>;
// flush?: FlushFunction<InputType, OutputType>;
// readableType?: undefined; // for future spec changes
// writableType?: undefined; // for future spec changes
// }
// export declare class TransformStream<InputType, OutputType> {
// constructor(
// transformer: Transformer<InputType, OutputType>,
// writableStrategy: QueuingStrategy<InputType>,
// readableStrategy: QueuingStrategy<OutputType>
// );
// readonly readable: rs.SDReadableStream<OutputType>;
// readonly writable: ws.WritableStream<InputType>;
// [backpressure_]: boolean | undefined; // Whether there was backpressure on [[readable]] the last time it was observed
// [backpressureChangePromise_]: shared.ControlledPromise<void> | undefined; // A promise which is fulfilled and replaced every time the value of[[backpressure]] changes
// [readable_]: rs.SDReadableStream<OutputType>; // The ReadableStream instance controlled by this object
// [transformStreamController_]: TransformStreamDefaultController<
// InputType,
// OutputType
// >; // A TransformStreamDefaultController created with the ability to control[[readable]] and[[writable]]; also used for the IsTransformStream brand check
// [writable_]: ws.WritableStream<InputType>; // The WritableStream instance controlled by this object
// }
// // ---- TransformStream
// export function isTransformStream(
// value: unknown
// ): value is TransformStream<any, any> {
// if (typeof value !== "object" || value === null) {
// return false;
// }
// return transformStreamController_ in value;
// }
// export function initializeTransformStream<InputType, OutputType>(
// stream: TransformStream<InputType, OutputType>,
// startPromise: Promise<void>,
// writableHighWaterMark: number,
// writableSizeAlgorithm: QueuingStrategySizeCallback<InputType>,
// readableHighWaterMark: number,
// readableSizeAlgorithm: QueuingStrategySizeCallback<OutputType>
// ): void {
// const startAlgorithm = function(): Promise<void> {
// return startPromise;
// };
// const writeAlgorithm = function(chunk: InputType): Promise<void> {
// return transformStreamDefaultSinkWriteAlgorithm(stream, chunk);
// };
// const abortAlgorithm = function(reason: shared.ErrorResult): Promise<void> {
// return transformStreamDefaultSinkAbortAlgorithm(stream, reason);
// };
// const closeAlgorithm = function(): Promise<void> {
// return transformStreamDefaultSinkCloseAlgorithm(stream);
// };
// stream[writable_] = createWritableStream<InputType>(
// startAlgorithm,
// writeAlgorithm,
// closeAlgorithm,
// abortAlgorithm,
// writableHighWaterMark,
// writableSizeAlgorithm
// );
// const pullAlgorithm = function(): Promise<void> {
// return transformStreamDefaultSourcePullAlgorithm(stream);
// };
// const cancelAlgorithm = function(
// reason: shared.ErrorResult
// ): Promise<undefined> {
// transformStreamErrorWritableAndUnblockWrite(stream, reason);
// return Promise.resolve(undefined);
// };
// stream[readable_] = createReadableStream(
// startAlgorithm,
// pullAlgorithm,
// cancelAlgorithm,
// readableHighWaterMark,
// readableSizeAlgorithm
// );
// stream[backpressure_] = undefined;
// stream[backpressureChangePromise_] = undefined;
// transformStreamSetBackpressure(stream, true);
// stream[transformStreamController_] = undefined!; // initialize slot for brand-check
// }
// export function transformStreamError<InputType, OutputType>(
// stream: TransformStream<InputType, OutputType>,
// error: shared.ErrorResult
// ): void {
// rs.readableStreamDefaultControllerError(
// stream[readable_][
// rs.readableStreamController_
// ] as rs.SDReadableStreamDefaultController<OutputType>,
// error
// );
// transformStreamErrorWritableAndUnblockWrite(stream, error);
// }
// export function transformStreamErrorWritableAndUnblockWrite<
// InputType,
// OutputType
// >(
// stream: TransformStream<InputType, OutputType>,
// error: shared.ErrorResult
// ): void {
// transformStreamDefaultControllerClearAlgorithms(
// stream[transformStreamController_]
// );
// ws.writableStreamDefaultControllerErrorIfNeeded(
// stream[writable_][ws.writableStreamController_]!,
// error
// );
// if (stream[backpressure_]) {
// transformStreamSetBackpressure(stream, false);
// }
// }
// export function transformStreamSetBackpressure<InputType, OutputType>(
// stream: TransformStream<InputType, OutputType>,
// backpressure: boolean
// ): void {
// // Assert: stream.[[backpressure]] is not backpressure.
// if (stream[backpressure_] !== undefined) {
// stream[backpressureChangePromise_]!.resolve(undefined);
// }
// stream[backpressureChangePromise_] = shared.createControlledPromise<void>();
// stream[backpressure_] = backpressure;
// }
// // ---- TransformStreamDefaultController
// export function isTransformStreamDefaultController(
// value: unknown
// ): value is TransformStreamDefaultController<any, any> {
// if (typeof value !== "object" || value === null) {
// return false;
// }
// return controlledTransformStream_ in value;
// }
// export function setUpTransformStreamDefaultController<InputType, OutputType>(
// stream: TransformStream<InputType, OutputType>,
// controller: TransformStreamDefaultController<InputType, OutputType>,
// transformAlgorithm: TransformAlgorithm<InputType>,
// flushAlgorithm: FlushAlgorithm
// ): void {
// // Assert: ! IsTransformStream(stream) is true.
// // Assert: stream.[[transformStreamController]] is undefined.
// controller[controlledTransformStream_] = stream;
// stream[transformStreamController_] = controller;
// controller[transformAlgorithm_] = transformAlgorithm;
// controller[flushAlgorithm_] = flushAlgorithm;
// }
// export function transformStreamDefaultControllerClearAlgorithms<
// InputType,
// OutputType
// >(controller: TransformStreamDefaultController<InputType, OutputType>): void {
// // Use ! assertions to override type check here, this way we don't
// // have to perform type checks/assertions everywhere else.
// controller[transformAlgorithm_] = undefined!;
// controller[flushAlgorithm_] = undefined!;
// }
// export function transformStreamDefaultControllerEnqueue<InputType, OutputType>(
// controller: TransformStreamDefaultController<InputType, OutputType>,
// chunk: OutputType
// ): void {
// const stream = controller[controlledTransformStream_];
// const readableController = stream[readable_][
// rs.readableStreamController_
// ] as rs.SDReadableStreamDefaultController<OutputType>;
// if (
// !rs.readableStreamDefaultControllerCanCloseOrEnqueue(readableController)
// ) {
// throw new TypeError();
// }
// try {
// rs.readableStreamDefaultControllerEnqueue(readableController, chunk);
// } catch (error) {
// transformStreamErrorWritableAndUnblockWrite(stream, error);
// throw stream[readable_][shared.storedError_];
// }
// const backpressure = rs.readableStreamDefaultControllerHasBackpressure(
// readableController
// );
// if (backpressure !== stream[backpressure_]) {
// // Assert: backpressure is true.
// transformStreamSetBackpressure(stream, true);
// }
// }
// export function transformStreamDefaultControllerError<InputType, OutputType>(
// controller: TransformStreamDefaultController<InputType, OutputType>,
// error: shared.ErrorResult
// ): void {
// transformStreamError(controller[controlledTransformStream_], error);
// }
// export function transformStreamDefaultControllerPerformTransform<
// InputType,
// OutputType
// >(
// controller: TransformStreamDefaultController<InputType, OutputType>,
// chunk: InputType
// ): Promise<void> {
// const transformPromise = controller[transformAlgorithm_](chunk);
// return transformPromise.catch(error => {
// transformStreamError(controller[controlledTransformStream_], error);
// throw error;
// });
// }
// export function transformStreamDefaultControllerTerminate<
// InputType,
// OutputType
// >(controller: TransformStreamDefaultController<InputType, OutputType>): void {
// const stream = controller[controlledTransformStream_];
// const readableController = stream[readable_][
// rs.readableStreamController_
// ] as rs.SDReadableStreamDefaultController<OutputType>;
// if (rs.readableStreamDefaultControllerCanCloseOrEnqueue(readableController)) {
// rs.readableStreamDefaultControllerClose(readableController);
// }
// const error = new TypeError("The transform stream has been terminated");
// transformStreamErrorWritableAndUnblockWrite(stream, error);
// }
// // ---- Transform Sinks
// export function transformStreamDefaultSinkWriteAlgorithm<InputType, OutputType>(
// stream: TransformStream<InputType, OutputType>,
// chunk: InputType
// ): Promise<void> {
// // Assert: stream.[[writable]].[[state]] is "writable".
// const controller = stream[transformStreamController_];
// if (stream[backpressure_]) {
// const backpressureChangePromise = stream[backpressureChangePromise_]!;
// // Assert: backpressureChangePromise is not undefined.
// return backpressureChangePromise.promise.then(_ => {
// const writable = stream[writable_];
// const state = writable[shared.state_];
// if (state === "erroring") {
// throw writable[shared.storedError_];
// }
// // Assert: state is "writable".
// return transformStreamDefaultControllerPerformTransform(
// controller,
// chunk
// );
// });
// }
// return transformStreamDefaultControllerPerformTransform(controller, chunk);
// }
// export function transformStreamDefaultSinkAbortAlgorithm<InputType, OutputType>(
// stream: TransformStream<InputType, OutputType>,
// reason: shared.ErrorResult
// ): Promise<void> {
// transformStreamError(stream, reason);
// return Promise.resolve(undefined);
// }
// export function transformStreamDefaultSinkCloseAlgorithm<InputType, OutputType>(
// stream: TransformStream<InputType, OutputType>
// ): Promise<void> {
// const readable = stream[readable_];
// const controller = stream[transformStreamController_];
// const flushPromise = controller[flushAlgorithm_]();
// transformStreamDefaultControllerClearAlgorithms(controller);
// return flushPromise.then(
// _ => {
// if (readable[shared.state_] === "errored") {
// throw readable[shared.storedError_];
// }
// const readableController = readable[
// rs.readableStreamController_
// ] as rs.SDReadableStreamDefaultController<OutputType>;
// if (
// rs.readableStreamDefaultControllerCanCloseOrEnqueue(readableController)
// ) {
// rs.readableStreamDefaultControllerClose(readableController);
// }
// },
// error => {
// transformStreamError(stream, error);
// throw readable[shared.storedError_];
// }
// );
// }
// // ---- Transform Sources
// export function transformStreamDefaultSourcePullAlgorithm<
// InputType,
// OutputType
// >(stream: TransformStream<InputType, OutputType>): Promise<void> {
// // Assert: stream.[[backpressure]] is true.
// // Assert: stream.[[backpressureChangePromise]] is not undefined.
// transformStreamSetBackpressure(stream, false);
// return stream[backpressureChangePromise_]!.promise;
// }