stream: simplify howMuchToRead()

This slightly refactors read by moving side effects out of
howMuchToRead().

We don't actually have to set state.needReadable = true; in
howMuchToRead() since read handles 0 return as needReadable.

PR-URL: https://github.com/nodejs/node/pull/29155
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
This commit is contained in:
Robert Nagy 2019-08-16 10:16:23 +02:00 committed by Rich Trott
parent cc7cec25c5
commit ea765eba20

View File

@ -386,17 +386,9 @@ function howMuchToRead(n, state) {
else
return state.length;
}
// If we're asking for more than the current hwm, then raise the hwm.
if (n > state.highWaterMark)
state.highWaterMark = computeNewHighWaterMark(n);
if (n <= state.length)
return n;
// Don't have enough
if (!state.ended) {
state.needReadable = true;
return 0;
}
return state.length;
return state.ended ? state.length : 0;
}
// You can override either this method, or the async _read(n) below.
@ -412,6 +404,10 @@ Readable.prototype.read = function(n) {
const state = this._readableState;
const nOrig = n;
// If we're asking for more than the current hwm, then raise the hwm.
if (n > state.highWaterMark)
state.highWaterMark = computeNewHighWaterMark(n);
if (n !== 0)
state.emittedReadable = false;