diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js index bf646f99ace7e6..c4405314a43296 100644 --- a/lib/_stream_readable.js +++ b/lib/_stream_readable.js @@ -161,6 +161,19 @@ Readable.prototype.setEncoding = function(enc) { this._readableState.decoder = new StringDecoder(enc); }; +// Don't raise the hwm > 128MB +var MAX_HWM = 0x800000; +function roundUpToNextPowerOf2(n) { + if (n >= MAX_HWM) { + n = MAX_HWM; + } else { + // Get the next highest power of 2 + n--; + for (var p = 1; p < 32; p <<= 1) n |= n >> p; + n++; + } + return n; +} function howMuchToRead(n, state) { if (state.length === 0 && state.ended) @@ -181,9 +194,11 @@ function howMuchToRead(n, state) { return 0; // If we're asking for more than the target buffer level, - // then raise the water mark. + // then raise the water mark. Bump up to the next highest + // power of 2, to prevent increasing it excessively in tiny + // amounts. if (n > state.highWaterMark) - state.highWaterMark = n; + state.highWaterMark = roundUpToNextPowerOf2(n); // don't have that much. return null, unless we've ended. if (n > state.length) { diff --git a/test/simple/test-stream-readable-flow-recursion.js b/test/simple/test-stream-readable-flow-recursion.js index bc4fd0ccee24e2..2891ad6db8dbb9 100644 --- a/test/simple/test-stream-readable-flow-recursion.js +++ b/test/simple/test-stream-readable-flow-recursion.js @@ -34,9 +34,15 @@ process.throwDeprecation = true; var stream = new Readable({ highWaterMark: 2 }); var reads = 0; +var total = 5000; stream._read = function(size) { reads++; - stream.push(new Buffer(size)); + size = Math.min(size, total); + total -= size; + if (size === 0) + stream.push(null); + else + stream.push(new Buffer(size)); }; var depth = 0; @@ -61,8 +67,9 @@ flow(stream, 5000, function() { process.on('exit', function(code) { assert.equal(reads, 2); // we pushed up the high water mark - assert.equal(stream._readableState.highWaterMark, 5000); - assert.equal(stream._readableState.length, 5000); + assert.equal(stream._readableState.highWaterMark, 8192); + // length is 0 right now, because we pulled it all out. + assert.equal(stream._readableState.length, 0); assert(!code); assert.equal(depth, 0); console.log('ok');