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denoland-deno/js/util.ts
Ryan Dahl 0d03fafbfe Map promises onto futures.
Refactors handlers.rs

The idea is that all Deno "ops" (aka bindings) should map onto
a Rust Future. By setting the "sync" flag in the Base message
users can determine if the future is executed immediately or put
on the event loop.

In the case of async futures, a promise is automatically created.
Errors are automatically forwarded and raised.

TODO:

- The file system ops in src/handler.rs are not using the thread pool
  yet. This will be done in the future using tokio_threadpool::blocking.
  That is, if you try to call them asynchronously, you will get a promise
  and it will act asynchronous, but currently it will be blocking.
- Handlers in src/handler.rs returned boxed futures. This was to make
  it easy while developing. We should try to remove this allocation.
2018-09-09 18:47:22 -04:00

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2.4 KiB
TypeScript

// Copyright 2018 the Deno authors. All rights reserved. MIT license.
import { TypedArray } from "./types";
let logDebug = false;
// @internal
export function setLogDebug(debug: boolean): void {
logDebug = debug;
}
/**
* Debug logging for deno. Enable with the `--DEBUG` command line flag.
* @internal
*/
// tslint:disable-next-line:no-any
export function log(...args: any[]): void {
if (logDebug) {
console.log("DEBUG JS -", ...args);
}
}
// @internal
export function assert(cond: boolean, msg = "assert") {
if (!cond) {
throw Error(msg);
}
}
// @internal
export function typedArrayToArrayBuffer(ta: TypedArray): ArrayBuffer {
const ab = ta.buffer.slice(ta.byteOffset, ta.byteOffset + ta.byteLength);
return ab as ArrayBuffer;
}
// @internal
export function arrayToStr(ui8: Uint8Array): string {
return String.fromCharCode(...ui8);
}
/**
* A `Resolvable` is a Promise with the `reject` and `resolve` functions
* placed as methods on the promise object itself. It allows you to do:
*
* const p = createResolvable<number>();
* ...
* p.resolve(42);
*
* It'd be prettier to make Resolvable a class that inherits from Promise,
* rather than an interface. This is possible in ES2016, however typescript
* produces broken code when targeting ES5 code.
* See https://github.com/Microsoft/TypeScript/issues/15202
* At the time of writing, the github issue is closed but the problem remains.
*
* @internal
*/
export interface ResolvableMethods<T> {
resolve: (value?: T | PromiseLike<T>) => void;
// tslint:disable-next-line:no-any
reject: (reason?: any) => void;
}
// @internal
export type Resolvable<T> = Promise<T> & ResolvableMethods<T>;
// @internal
export function createResolvable<T>(): Resolvable<T> {
let methods: ResolvableMethods<T>;
const promise = new Promise<T>((resolve, reject) => {
methods = { resolve, reject };
});
// TypeScript doesn't know that the Promise callback occurs synchronously
// therefore use of not null assertion (`!`)
return Object.assign(promise, methods!) as Resolvable<T>;
}
// @internal
export function notImplemented(): never {
throw new Error("Not implemented");
}
// @internal
export function unreachable(): never {
throw new Error("Code not reachable");
}
export function hexdump(u8: Uint8Array): string {
return Array.prototype.map
.call(u8, (x: number) => {
return ("00" + x.toString(16)).slice(-2);
})
.join(" ");
}