1
0
Fork 0
mirror of https://github.com/denoland/deno.git synced 2024-12-22 15:24:46 -05:00

stabilize Deno.iter() and Deno.iterSync() (#4890)

This commit is contained in:
Bartek Iwańczuk 2020-04-25 00:05:48 +02:00 committed by GitHub
parent 824329f0da
commit e9fa6b87ce
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
3 changed files with 46 additions and 30 deletions

View file

@ -6,6 +6,8 @@
export const EOF: unique symbol = Symbol("EOF");
export type EOF = typeof EOF;
const DEFAULT_BUFFER_SIZE = 32 * 1024;
// Seek whence values.
// https://golang.org/pkg/io/#pkg-constants
export enum SeekMode {
@ -71,7 +73,7 @@ export interface ReadWriteSeeker extends Reader, Writer, Seeker {}
// https://golang.org/pkg/io/#Copy
export async function copy(dst: Writer, src: Reader): Promise<number> {
let n = 0;
const b = new Uint8Array(32 * 1024);
const b = new Uint8Array(DEFAULT_BUFFER_SIZE);
let gotEOF = false;
while (gotEOF === false) {
const result = await src.read(b);
@ -86,9 +88,12 @@ export async function copy(dst: Writer, src: Reader): Promise<number> {
export async function* iter(
r: Reader,
bufSize?: number
options?: {
bufSize?: number;
}
): AsyncIterableIterator<Uint8Array> {
const b = new Uint8Array(bufSize ?? 1024);
const bufSize = options?.bufSize ?? DEFAULT_BUFFER_SIZE;
const b = new Uint8Array(bufSize);
while (true) {
const result = await r.read(b);
if (result === EOF) {
@ -101,9 +106,12 @@ export async function* iter(
export function* iterSync(
r: SyncReader,
bufSize?: number
options?: {
bufSize?: number;
}
): IterableIterator<Uint8Array> {
const b = new Uint8Array(bufSize ?? 1024);
const bufSize = options?.bufSize ?? DEFAULT_BUFFER_SIZE;
const b = new Uint8Array(bufSize);
while (true) {
const result = r.readSync(b);
if (result === EOF) {

View file

@ -576,60 +576,68 @@ declare namespace Deno {
*/
export function copy(dst: Writer, src: Reader): Promise<number>;
/** **UNSTABLE**: new API, yet to be vetted
* Turns a Reader, `r`, into an async iterator.
/** Turns a Reader, `r`, into an async iterator.
*
* let f = await open("/etc/passwd");
* for await (const chunk of iter(f)) {
* let f = await Deno.open("/etc/passwd");
* for await (const chunk of Deno.iter(f)) {
* console.log(chunk);
* }
* f.close();
*
* Second argument can be used to tune size of a buffer.
* Default size of the buffer is 1024 bytes.
* Default size of the buffer is 32kB.
*
* let f = await open("/etc/passwd");
* for await (const chunk of iter(f, 1024 * 1024)) {
* let f = await Deno.open("/etc/passwd");
* const iter = Deno.iter(f, {
* bufSize: 1024 * 1024
* });
* for await (const chunk of iter) {
* console.log(chunk);
* }
* f.close();
*
* Iterator uses internal buffer of fixed size for efficiency returning
* a view on that buffer on each iteration. It it therefore callers
* responsibility to copy contents of the buffer if needed; otherwise
* Iterator uses an internal buffer of fixed size for efficiency; it returns
* a view on that buffer on each iteration. It is therefore caller's
* responsibility to copy contents of the buffer if needed; otherwise the
* next iteration will overwrite contents of previously returned chunk.
*/
export function iter(
r: Reader,
bufSize?: number
options?: {
bufSize?: number;
}
): AsyncIterableIterator<Uint8Array>;
/** **UNSTABLE**: new API, yet to be vetted
* Turns a SyncReader, `r`, into an iterator.
/** Turns a SyncReader, `r`, into an iterator.
*
* let f = openSync("/etc/passwd");
* for (const chunk of iterSync(reader)) {
* let f = Deno.openSync("/etc/passwd");
* for (const chunk of Deno.iterSync(reader)) {
* console.log(chunk);
* }
* f.close();
*
* Second argument can be used to tune size of a buffer.
* Default size of the buffer is 1024 bytes.
* Default size of the buffer is 32kB.
*
* let f = openSync("/etc/passwd");
* for (const chunk of iterSync(reader, 1024 * 1024)) {
* let f = await Deno.open("/etc/passwd");
* const iter = Deno.iterSync(f, {
* bufSize: 1024 * 1024
* });
* for (const chunk of iter) {
* console.log(chunk);
* }
* f.close()
* f.close();
*
* Iterator uses internal buffer of fixed size for efficiency returning
* a view on that buffer on each iteration. It it therefore callers
* responsibility to copy contents of the buffer if needed; otherwise
* Iterator uses an internal buffer of fixed size for efficiency; it returns
* a view on that buffer on each iteration. It is therefore caller's
* responsibility to copy contents of the buffer if needed; otherwise the
* next iteration will overwrite contents of previously returned chunk.
*/
export function iterSync(
r: SyncReader,
bufSize?: number
options?: {
bufSize?: number;
}
): IterableIterator<Uint8Array>;
/** Synchronously open a file and return an instance of `Deno.File`. The

View file

@ -46,7 +46,7 @@ unitTest(
let totalSize = 0;
let iterations = 0;
for await (const buf of Deno.iter(file, 6)) {
for await (const buf of Deno.iter(file, { bufSize: 6 })) {
totalSize += buf.byteLength;
iterations += 1;
}
@ -78,7 +78,7 @@ unitTest(
let totalSize = 0;
let iterations = 0;
for (const buf of Deno.iterSync(file, 6)) {
for (const buf of Deno.iterSync(file, { bufSize: 6 })) {
totalSize += buf.byteLength;
iterations += 1;
}