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denoland-deno/js/truncate.ts
2018-10-01 22:30:57 -04:00

42 lines
1.2 KiB
TypeScript

// Copyright 2018 the Deno authors. All rights reserved. MIT license.
import * as fbs from "gen/msg_generated";
import { flatbuffers } from "flatbuffers";
import * as dispatch from "./dispatch";
/**
* Truncates or extends the specified file synchronously,
* updating the size of this file to become size.
*
* import { truncateSync } from "deno";
*
* truncateSync("hello.txt", 10);
*/
export function truncateSync(name: string, len?: number): void {
dispatch.sendSync(...req(name, len));
}
/**
* Truncates or extends the specified file,
* updating the size of this file to become size.
*
* import { truncate } from "deno";
*
* await truncate("hello.txt", 10);
*/
export async function truncate(name: string, len?: number): Promise<void> {
await dispatch.sendAsync(...req(name, len));
}
function req(
name: string,
len?: number
): [flatbuffers.Builder, fbs.Any, flatbuffers.Offset] {
const builder = new flatbuffers.Builder();
const name_ = builder.createString(name);
len = len && len > 0 ? Math.floor(len) : 0;
fbs.Truncate.startTruncate(builder);
fbs.Truncate.addName(builder, name_);
fbs.Truncate.addLen(builder, len);
const msg = fbs.Truncate.endTruncate(builder);
return [builder, fbs.Any.Truncate, msg];
}