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nodejs/test/simple/test-stream2-large-read-stall.js
isaacs 14e8f806de stream: Properly handle large reads from push-streams
Problem 1: If stream.push() triggers a 'readable' event, and the user
calls `read(n)` with some n > the highWaterMark, then the push() will
return false (indicating that they should not push any more), but no
future 'readable' event is coming (because we're above the
highWaterMark).

Solution: return true from push() when needReadable is set.

Problem 2: A read(n) for n != 0, after the stream had encountered an
EOF, would not trigger the 'end' event if the EOF was pushed in
synchronously by the _read() function.

Solution: Check for ended in stream.read() and schedule an end event if
the length now equals 0.

Fix #4585
2013-01-16 10:45:11 -08:00

83 lines
2.4 KiB
JavaScript

// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
var common = require('../common.js');
var assert = require('assert');
// If everything aligns so that you do a read(n) of exactly the
// remaining buffer, then make sure that 'end' still emits.
var READSIZE = 100;
var PUSHSIZE = 20;
var PUSHCOUNT = 1000;
var HWM = 50;
var Readable = require('stream').Readable;
var r = new Readable({
highWaterMark: HWM
});
var rs = r._readableState;
r._read = push;
r.on('readable', function() {
console.error('>> readable');
do {
console.error(' > read(%d)', READSIZE);
var ret = r.read(READSIZE);
console.error(' < %j (%d remain)', ret && ret.length, rs.length);
} while (ret && ret.length === READSIZE);
console.error('<< after read()',
ret && ret.length,
rs.needReadable,
rs.length);
});
var endEmitted = false;
r.on('end', function() {
endEmitted = true;
console.error('end');
});
var pushes = 0;
function push() {
if (pushes > PUSHCOUNT)
return;
if (pushes++ === PUSHCOUNT) {
console.error(' push(EOF)');
return r.push(null);
}
console.error(' push #%d', pushes);
if (r.push(new Buffer(PUSHSIZE)))
setTimeout(push);
}
// start the flow
var ret = r.read(0);
process.on('exit', function() {
assert.equal(pushes, PUSHCOUNT + 1);
assert(endEmitted);
});