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Code Issues Releases Activity

stream: avoid additional validation for Buffers

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These changes result in ~50% improvement in the included benchmark.

PR-URL: https://github.com/nodejs/node/pull/10580
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
This commit is contained in:
Brian White 2017-01-02 18:37:26 -05:00
parent aab1dd6ff4
commit 0a937280d8
No known key found for this signature in database
GPG Key ID: 606D7358F94DA209
2 changed files with 40 additions and 20 deletions
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23
benchmark/streams/writable-manywrites.js Normal file
View File

@ -0,0 +1,23 @@
'use strict';
const common = require('../common');
const Writable = require('stream').Writable;
const bench = common.createBenchmark(main, {
n: [2e6]
});
function main(conf) {
const n = +conf.n;
const b = Buffer.allocUnsafe(1024);
const s = new Writable();
s._write = function(chunk, encoding, cb) {
cb();
};
bench.start();
for (var k = 0; k < n; ++k) {
s.write(b);
}
bench.end(n);
}

37
lib/_stream_writable.js
View File

@ -194,23 +194,18 @@ function writeAfterEnd(stream, cb) {
process.nextTick(cb, er);
}
// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
// Checks that a user-supplied chunk is valid, especially for the particular
// mode the stream is in. Currently this means that `null` is never accepted
// and undefined/non-string values are only allowed in object mode.
function validChunk(stream, state, chunk, cb) {
var valid = true;
var er = false;
// Always throw error if a null is written
// if we are not in object mode then throw
// if it is not a buffer, string, or undefined.
if (chunk === null) {
er = new TypeError('May not write null values to stream');
} else if (!(chunk instanceof Buffer) &&
typeof chunk !== 'string' &&
chunk !== undefined &&
!state.objectMode) {
} else if (typeof chunk !== 'string' &&
chunk !== undefined &&
!state.objectMode) {
er = new TypeError('Invalid non-string/buffer chunk');
}
if (er) {
@ -224,13 +219,14 @@ function validChunk(stream, state, chunk, cb) {
Writable.prototype.write = function(chunk, encoding, cb) {
var state = this._writableState;
var ret = false;
var isBuf = (chunk instanceof Buffer);
if (typeof encoding === 'function') {
cb = encoding;
encoding = null;
}
if (chunk instanceof Buffer)
if (isBuf)
encoding = 'buffer';
else if (!encoding)
encoding = state.defaultEncoding;
@ -240,9 +236,9 @@ Writable.prototype.write = function(chunk, encoding, cb) {
if (state.ended)
writeAfterEnd(this, cb);
else if (validChunk(this, state, chunk, cb)) {
else if (isBuf || validChunk(this, state, chunk, cb)) {
state.pendingcb++;
ret = writeOrBuffer(this, state, chunk, encoding, cb);
ret = writeOrBuffer(this, state, isBuf, chunk, encoding, cb);
}
return ret;
@ -291,11 +287,12 @@ function decodeChunk(state, chunk, encoding) {
// if we're already writing something, then just put this
// in the queue, and wait our turn. Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
chunk = decodeChunk(state, chunk, encoding);
if (chunk instanceof Buffer)
encoding = 'buffer';
function writeOrBuffer(stream, state, isBuf, chunk, encoding, cb) {
if (!isBuf) {
chunk = decodeChunk(state, chunk, encoding);
if (chunk instanceof Buffer)
encoding = 'buffer';
}
var len = state.objectMode ? 1 : chunk.length;
state.length += len;