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// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import { sendAsyncMinimal, sendSyncMinimal } from "./dispatch_minimal.ts";
import { EOF } from "../io.ts";
// TODO(bartlomieju): remove this import and maybe lazy-initialize
// OPS_CACHE that belongs only to this module
import { OPS_CACHE } from "../runtime.ts";
// This is done because read/write are extremely performance sensitive.
let OP_READ = -1;
let OP_WRITE = -1;
/** Synchronously read from a file ID into an array buffer.
*
* Returns `number | EOF` for the operation.
*
* const file = Deno.openSync("/foo/bar.txt");
* const buf = new Uint8Array(100);
* const nread = Deno.readSync(file.rid, buf);
* const text = new TextDecoder().decode(buf);
*/
export function readSync(rid: number, p: Uint8Array): number | EOF {
if (p.length == 0) {
return 0;
}
if (OP_READ < 0) {
OP_READ = OPS_CACHE["op_read"];
}
const nread = sendSyncMinimal(OP_READ, rid, p);
if (nread < 0) {
throw new Error("read error");
} else if (nread == 0) {
return EOF;
} else {
return nread;
}
}
/** Read from a resource ID into an array buffer.
*
* Resolves to the `number | EOF` for the operation.
*
* const file = await Deno.open("/foo/bar.txt");
* const buf = new Uint8Array(100);
* const nread = await Deno.read(file.rid, buf);
* const text = new TextDecoder().decode(buf);
*/
export async function read(rid: number, p: Uint8Array): Promise<number | EOF> {
if (p.length == 0) {
return 0;
}
if (OP_READ < 0) {
OP_READ = OPS_CACHE["op_read"];
}
const nread = await sendAsyncMinimal(OP_READ, rid, p);
if (nread < 0) {
throw new Error("read error");
} else if (nread == 0) {
return EOF;
} else {
return nread;
}
}
/** Synchronously write to the resource ID the contents of the array buffer.
*
* Resolves to the number of bytes written.
*
* const encoder = new TextEncoder();
* const data = encoder.encode("Hello world\n");
* const file = Deno.openSync("/foo/bar.txt", {create: true, write: true});
* Deno.writeSync(file.rid, data);
*/
export function writeSync(rid: number, p: Uint8Array): number {
if (OP_WRITE < 0) {
OP_WRITE = OPS_CACHE["op_write"];
}
const result = sendSyncMinimal(OP_WRITE, rid, p);
if (result < 0) {
throw new Error("write error");
} else {
return result;
}
}
/** Write to the resource ID the contents of the array buffer.
*
* Resolves to the number of bytes written.
*
* const encoder = new TextEncoder();
* const data = encoder.encode("Hello world\n");
* const file = await Deno.open("/foo/bar.txt", {create: true, write: true});
* await Deno.write(file.rid, data);
*/
export async function write(rid: number, p: Uint8Array): Promise<number> {
if (OP_WRITE < 0) {
OP_WRITE = OPS_CACHE["op_write"];
}
const result = await sendAsyncMinimal(OP_WRITE, rid, p);
if (result < 0) {
throw new Error("write error");
} else {
return result;
}
}
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