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stream: optimize creation

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PR-URL: https://github.com/nodejs/node/pull/29135
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
This commit is contained in:
Robert Nagy 2019-08-15 13:06:51 +02:00 committed by zhangyongsheng
parent 8235ffd786
commit bd02775af8
2 changed files with 28 additions and 22 deletions
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25
lib/_stream_readable.js
View File

@ -33,7 +33,10 @@ const { Buffer } = require('buffer');
const debug = require('internal/util/debuglog').debuglog('stream');
const BufferList = require('internal/streams/buffer_list');
const destroyImpl = require('internal/streams/destroy');
const { getHighWaterMark } = require('internal/streams/state');
const {
getHighWaterMark,
getDefaultHighWaterMark
} = require('internal/streams/state');
const {
ERR_INVALID_ARG_TYPE,
ERR_STREAM_PUSH_AFTER_EOF,
@ -70,8 +73,6 @@ function prependListener(emitter, event, fn) {
}
function ReadableState(options, stream, isDuplex) {
options = options || {};
// Duplex streams are both readable and writable, but share
// the same options object.
// However, some cases require setting options to different
@ -82,15 +83,17 @@ function ReadableState(options, stream, isDuplex) {
// Object stream flag. Used to make read(n) ignore n and to
// make all the buffer merging and length checks go away
this.objectMode = !!options.objectMode;
this.objectMode = !!(options && options.objectMode);
if (isDuplex)
this.objectMode = this.objectMode || !!options.readableObjectMode;
this.objectMode = this.objectMode ||
!!(options && options.readableObjectMode);
// The point at which it stops calling _read() to fill the buffer
// Note: 0 is a valid value, means "don't call _read preemptively ever"
this.highWaterMark = getHighWaterMark(this, options, 'readableHighWaterMark',
isDuplex);
this.highWaterMark = options ?
getHighWaterMark(this, options, 'readableHighWaterMark', isDuplex) :
getDefaultHighWaterMark(false);
// A linked list is used to store data chunks instead of an array because the
// linked list can remove elements from the beginning faster than
@ -121,10 +124,10 @@ function ReadableState(options, stream, isDuplex) {
this.errorEmitted = false;
// Should close be emitted on destroy. Defaults to true.
this.emitClose = options.emitClose !== false;
this.emitClose = !options || options.emitClose !== false;
// Should .destroy() be called after 'end' (and potentially 'finish')
this.autoDestroy = !!options.autoDestroy;
this.autoDestroy = !!(options && options.autoDestroy);
// Has it been destroyed
this.destroyed = false;
@ -132,7 +135,7 @@ function ReadableState(options, stream, isDuplex) {
// Crypto is kind of old and crusty. Historically, its default string
// encoding is 'binary' so we have to make this configurable.
// Everything else in the universe uses 'utf8', though.
this.defaultEncoding = options.defaultEncoding || 'utf8';
this.defaultEncoding = (options && options.defaultEncoding) || 'utf8';
// Ref the piped dest which we need a drain event on it
// type: null | Writable | Set<Writable>
@ -144,7 +147,7 @@ function ReadableState(options, stream, isDuplex) {
this.decoder = null;
this.encoding = null;
if (options.encoding) {
if (options && options.encoding) {
if (!StringDecoder)
StringDecoder = require('string_decoder').StringDecoder;
this.decoder = new StringDecoder(options.encoding);

25
lib/_stream_writable.js
View File

@ -34,7 +34,10 @@ const internalUtil = require('internal/util');
const Stream = require('stream');
const { Buffer } = require('buffer');
const destroyImpl = require('internal/streams/destroy');
const { getHighWaterMark } = require('internal/streams/state');
const {
getHighWaterMark,
getDefaultHighWaterMark
} = require('internal/streams/state');
const {
ERR_INVALID_ARG_TYPE,
ERR_METHOD_NOT_IMPLEMENTED,
@ -55,8 +58,6 @@ Object.setPrototypeOf(Writable, Stream);
function nop() {}
function WritableState(options, stream, isDuplex) {
options = options || {};
// Duplex streams are both readable and writable, but share
// the same options object.
// However, some cases require setting options to different
@ -67,16 +68,18 @@ function WritableState(options, stream, isDuplex) {
// Object stream flag to indicate whether or not this stream
// contains buffers or objects.
this.objectMode = !!options.objectMode;
this.objectMode = !!(options && options.objectMode);
if (isDuplex)
this.objectMode = this.objectMode || !!options.writableObjectMode;
this.objectMode = this.objectMode ||
!!(options && options.writableObjectMode);
// The point at which write() starts returning false
// Note: 0 is a valid value, means that we always return false if
// the entire buffer is not flushed immediately on write()
this.highWaterMark = getHighWaterMark(this, options, 'writableHighWaterMark',
isDuplex);
this.highWaterMark = options ?
getHighWaterMark(this, options, 'writableHighWaterMark', isDuplex) :
getDefaultHighWaterMark(false);
// if _final has been called
this.finalCalled = false;
@ -96,13 +99,13 @@ function WritableState(options, stream, isDuplex) {
// Should we decode strings into buffers before passing to _write?
// this is here so that some node-core streams can optimize string
// handling at a lower level.
const noDecode = options.decodeStrings === false;
const noDecode = !!(options && options.decodeStrings === false);
this.decodeStrings = !noDecode;
// Crypto is kind of old and crusty. Historically, its default string
// encoding is 'binary' so we have to make this configurable.
// Everything else in the universe uses 'utf8', though.
this.defaultEncoding = options.defaultEncoding || 'utf8';
this.defaultEncoding = (options && options.defaultEncoding) || 'utf8';
// Not an actual buffer we keep track of, but a measurement
// of how much we're waiting to get pushed to some underlying
@ -150,10 +153,10 @@ function WritableState(options, stream, isDuplex) {
this.errorEmitted = false;
// Should close be emitted on destroy. Defaults to true.
this.emitClose = options.emitClose !== false;
this.emitClose = !options || options.emitClose !== false;
// Should .destroy() be called after 'finish' (and potentially 'end')
this.autoDestroy = !!options.autoDestroy;
this.autoDestroy = !!(options && options.autoDestroy);
// Count buffered requests
this.bufferedRequestCount = 0;