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111 lines
3.4 KiB
TypeScript
111 lines
3.4 KiB
TypeScript
// Copyright 2018 the Deno authors. All rights reserved. MIT license.
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import { Reader, Writer, Closer, ReadResult } from "./io";
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import * as dispatch from "./dispatch";
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import * as msg from "gen/msg_generated";
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import { assert } from "./util";
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import * as flatbuffers from "./flatbuffers";
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/** The Deno abstraction for reading and writing files. */
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export class File implements Reader, Writer, Closer {
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constructor(readonly rid: number) {}
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write(p: ArrayBufferView): Promise<number> {
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return write(this.rid, p);
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}
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read(p: ArrayBufferView): Promise<ReadResult> {
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return read(this.rid, p);
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}
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close(): void {
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close(this.rid);
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}
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}
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/** An instance of `File` for stdin. */
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export const stdin = new File(0);
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/** An instance of `File` for stdout. */
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export const stdout = new File(1);
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/** An instance of `File` for stderr. */
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export const stderr = new File(2);
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// TODO This is just a placeholder - not final API.
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export type OpenMode = "r" | "w" | "w+" | "x";
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/** A factory function for creating instances of `File` associated with the
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* supplied file name.
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*/
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export function create(filename: string): Promise<File> {
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return open(filename, "x");
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}
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/** Open a file and return an instance of the `File` object.
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*
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* import * as deno from "deno";
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* (async () => {
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* const file = await deno.open("/foo/bar.txt");
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* })();
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*/
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export async function open(
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filename: string,
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mode: OpenMode = "r"
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): Promise<File> {
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const builder = flatbuffers.createBuilder();
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const filename_ = builder.createString(filename);
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msg.Open.startOpen(builder);
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msg.Open.addFilename(builder, filename_);
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const inner = msg.Open.endOpen(builder);
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const baseRes = await dispatch.sendAsync(builder, msg.Any.Open, inner);
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assert(baseRes != null);
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assert(msg.Any.OpenRes === baseRes!.innerType());
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const res = new msg.OpenRes();
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assert(baseRes!.inner(res) != null);
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const rid = res.rid();
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return new File(rid);
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}
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/** Read from a file ID into an array buffer.
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*
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* Resolves with the `ReadResult` for the operation.
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*/
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export async function read(
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rid: number,
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p: ArrayBufferView
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): Promise<ReadResult> {
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const builder = flatbuffers.createBuilder();
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msg.Read.startRead(builder);
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msg.Read.addRid(builder, rid);
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const inner = msg.Read.endRead(builder);
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const baseRes = await dispatch.sendAsync(builder, msg.Any.Read, inner, p);
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assert(baseRes != null);
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assert(msg.Any.ReadRes === baseRes!.innerType());
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const res = new msg.ReadRes();
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assert(baseRes!.inner(res) != null);
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return { nread: res.nread(), eof: res.eof() };
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}
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/** Write to the file ID the contents of the array buffer.
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*
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* Resolves with the number of bytes written.
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*/
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export async function write(rid: number, p: ArrayBufferView): Promise<number> {
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const builder = flatbuffers.createBuilder();
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msg.Write.startWrite(builder);
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msg.Write.addRid(builder, rid);
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const inner = msg.Write.endWrite(builder);
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const baseRes = await dispatch.sendAsync(builder, msg.Any.Write, inner, p);
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assert(baseRes != null);
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assert(msg.Any.WriteRes === baseRes!.innerType());
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const res = new msg.WriteRes();
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assert(baseRes!.inner(res) != null);
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return res.nbyte();
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}
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/** Close the file ID. */
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export function close(rid: number): void {
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const builder = flatbuffers.createBuilder();
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msg.Close.startClose(builder);
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msg.Close.addRid(builder, rid);
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const inner = msg.Close.endClose(builder);
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dispatch.sendSync(builder, msg.Any.Close, inner);
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}
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