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stream: avoid pause with unpipe in buffered write 

If a pipe is cleaned up (due to unpipe) during a write that
returned false, the source stream can get stuck in a paused state.

Fixes: https://github.com/nodejs/node/issues/2323
PR-URL: https://github.com/nodejs/node/pull/2325
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
This commit is contained in:
Brian White 2015-10-11 14:06:17 -04:00
parent 8e213096df
commit 68990948fe
2 changed files with 51 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
lib/_stream_readable.js
View File

@ -497,6 +497,7 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
var ondrain = pipeOnDrain(src);
dest.on('drain', ondrain);
var cleanedUp = false;
function cleanup() {
debug('cleanup');
// cleanup event handlers once the pipe is broken
@ -509,6 +510,8 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
src.removeListener('end', cleanup);
src.removeListener('data', ondata);
cleanedUp = true;
// if the reader is waiting for a drain event from this
// specific writer, then it would cause it to never start
// flowing again.
@ -524,9 +527,16 @@ Readable.prototype.pipe = function(dest, pipeOpts) {
debug('ondata');
var ret = dest.write(chunk);
if (false === ret) {
debug('false write response, pause',
src._readableState.awaitDrain);
src._readableState.awaitDrain++;
// If the user unpiped during `dest.write()`, it is possible
// to get stuck in a permanently paused state if that write
// also returned false.
if (state.pipesCount === 1 &&
state.pipes[0] === dest &&
src.listenerCount('data') === 1 &&
!cleanedUp) {
debug('false write response, pause', src._readableState.awaitDrain);
src._readableState.awaitDrain++;
}
src.pause();
}
}

38
test/parallel/test-stream-pipe-cleanup-pause.js Normal file
View File

@ -0,0 +1,38 @@
'use strict';
const common = require('../common');
const assert = require('assert');
const stream = require('stream');
const reader = new stream.Readable();
const writer1 = new stream.Writable();
const writer2 = new stream.Writable();
// 560000 is chosen here because it is larger than the (default) highWaterMark
// and will cause `.write()` to return false
// See: https://github.com/nodejs/node/issues/2323
const buffer = new Buffer(560000);
reader._read = function(n) {};
writer1._write = common.mustCall(function(chunk, encoding, cb) {
this.emit('chunk-received');
cb();
}, 1);
writer1.once('chunk-received', function() {
reader.unpipe(writer1);
reader.pipe(writer2);
reader.push(buffer);
setImmediate(function() {
reader.push(buffer);
setImmediate(function() {
reader.push(buffer);
});
});
});
writer2._write = common.mustCall(function(chunk, encoding, cb) {
cb();
}, 3);
reader.pipe(writer1);
reader.push(buffer);