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stream: improve writable.write() performance
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Backport-PR-URL: #32169
PR-URL: #31624
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
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mscdex authored and MylesBorins committed Mar 10, 2020
1 parent 90a4d43 commit 1e05ddf
Showing 1 changed file with 27 additions and 48 deletions.
75 changes: 27 additions & 48 deletions lib/_stream_writable.js
Original file line number Diff line number Diff line change
Expand Up @@ -268,35 +268,8 @@ Writable.prototype.pipe = function() {
};


function writeAfterEnd(stream, cb) {
const er = new ERR_STREAM_WRITE_AFTER_END();
// TODO: defer error events consistently everywhere, not just the cb
errorOrDestroy(stream, er);
process.nextTick(cb, er);
}

// 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 er;

if (chunk === null) {
er = new ERR_STREAM_NULL_VALUES();
} else if (typeof chunk !== 'string' && !state.objectMode) {
er = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
}
if (er) {
errorOrDestroy(stream, er);
process.nextTick(cb, er);
return false;
}
return true;
}

Writable.prototype.write = function(chunk, encoding, cb) {
const state = this._writableState;
var ret = false;
const isBuf = !state.objectMode && Stream._isUint8Array(chunk);

// Do not use Object.getPrototypeOf as it is slower since V8 7.3.
Expand All @@ -306,29 +279,42 @@ Writable.prototype.write = function(chunk, encoding, cb) {

if (typeof encoding === 'function') {
cb = encoding;
encoding = null;
encoding = state.defaultEncoding;
} else {
if (!encoding)
encoding = state.defaultEncoding;
if (typeof cb !== 'function')
cb = nop;
}

if (isBuf)
encoding = 'buffer';
else if (!encoding)
encoding = state.defaultEncoding;

if (typeof cb !== 'function')
cb = nop;

let err;
if (state.ending) {
writeAfterEnd(this, cb);
err = new ERR_STREAM_WRITE_AFTER_END();
} else if (state.destroyed) {
const err = new ERR_STREAM_DESTROYED('write');
process.nextTick(cb, err);
errorOrDestroy(this, err);
} else if (isBuf || validChunk(this, state, chunk, cb)) {
state.pendingcb++;
ret = writeOrBuffer(this, state, chunk, encoding, cb);
err = new ERR_STREAM_DESTROYED('write');
} else if (chunk === null) {
err = new ERR_STREAM_NULL_VALUES();
} else {
if (!isBuf && !state.objectMode) {
if (typeof chunk !== 'string') {
err = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
} else if (encoding !== 'buffer' && state.decodeStrings !== false) {
chunk = Buffer.from(chunk, encoding);
encoding = 'buffer';
}
}
if (err === undefined) {
state.pendingcb++;
return writeOrBuffer(this, state, chunk, encoding, cb);
}
}

return ret;
process.nextTick(cb, err);
errorOrDestroy(this, err, true);
return false;
};

Writable.prototype.cork = function() {
Expand Down Expand Up @@ -363,13 +349,6 @@ Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
// 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) {
if (!state.objectMode &&
state.decodeStrings !== false &&
encoding !== 'buffer' &&
typeof chunk === 'string') {
chunk = Buffer.from(chunk, encoding);
encoding = 'buffer';
}
const len = state.objectMode ? 1 : chunk.length;

state.length += len;
Expand Down

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