stream: Remove bufferSize option

Now that highWaterMark increases when there are large reads, this
greatly reduces the number of calls necessary to _read(size), assuming
that _read actually respects the size argument.

doc/api/stream.markdown

@@ -90,8 +90,6 @@ method. (See below.)
 ### new stream.Readable([options])
 
 * `options` {Object}
-  * `bufferSize` {Number} The size of the chunks to consume from the
-    underlying resource. Default=16kb
   * `highWaterMark` {Number} The maximum number of bytes to store in
     the internal buffer before ceasing to read from the underlying
     resource.  Default=16kb

lib/_stream_readable.js

@@ -32,16 +32,12 @@ util.inherits(Readable, Stream);
 function ReadableState(options, stream) {
   options = options || {};
 
-  // the argument passed to this._read(n)
-  this.bufferSize = options.bufferSize || 16 * 1024;
-
   // the point at which it stops calling _read() to fill the buffer
   // Note: 0 is a valid value, means "don't call _read preemptively ever"
   var hwm = options.highWaterMark;
   this.highWaterMark = (hwm || hwm === 0) ? hwm : 16 * 1024;
 
   // cast to ints.
-  this.bufferSize = ~~this.bufferSize;
   this.highWaterMark = ~~this.highWaterMark;
 
   this.buffer = [];
@@ -265,7 +261,7 @@ Readable.prototype.read = function(n) {
     if (state.length === 0)
       state.needReadable = true;
     // call internal read method
-    this._read(state.bufferSize);
+    this._read(state.highWaterMark);
     state.sync = false;
   }
 

lib/_stream_transform.js

@@ -102,7 +102,7 @@ function afterTransform(stream, er, data) {
 
   var rs = stream._readableState;
   if (rs.needReadable || rs.length < rs.highWaterMark) {
-    stream._read(rs.bufferSize);
+    stream._read(rs.highWaterMark);
   }
 }
 
@@ -165,7 +165,7 @@ Transform.prototype._write = function(chunk, encoding, cb) {
     if (ts.needTransform ||
         rs.needReadable ||
         rs.length < rs.highWaterMark)
-      this._read(rs.bufferSize);
+      this._read(rs.highWaterMark);
   }
 };
 

lib/fs.js

@@ -1431,7 +1431,6 @@ function ReadStream(path, options) {
 
   // a little bit bigger buffer and water marks by default
   options = util._extend({
-    bufferSize: 64 * 1024,
     highWaterMark: 64 * 1024
   }, options || {});
 
@@ -1505,10 +1504,9 @@ ReadStream.prototype._read = function(n) {
     return;
 
   if (!pool || pool.length - pool.used < kMinPoolSpace) {
-    // discard the old pool. Can't add to the free list because
-    // users might have refernces to slices on it.
+    // discard the old pool.
     pool = null;
-    allocNewPool(this._readableState.bufferSize);
+    allocNewPool(this._readableState.highWaterMark);
   }
 
   // Grab another reference to the pool in the case that while we're

test/simple/test-stream-readable-flow-recursion.js

@@ -32,7 +32,7 @@ var Readable = require('stream').Readable;
 // throw an error if we trigger a nextTick warning.
 process.throwDeprecation = true;
 
-var stream = new Readable({ highWaterMark: 2, bufferSize: 2 });
+var stream = new Readable({ highWaterMark: 2 });
 var reads = 0;
 stream._read = function(size) {
   reads++;
@@ -59,7 +59,7 @@ flow(stream, 5000, function() {
 });
 
 process.on('exit', function(code) {
-  assert.equal(reads, 5000);
+  assert.equal(reads, 2);
   // we pushed up the high water mark
   assert.equal(stream._readableState.highWaterMark, 5000);
   assert.equal(stream._readableState.length, 5000);

test/simple/test-stream2-fs.js

@@ -32,11 +32,7 @@ var file = path.resolve(common.fixturesDir, 'x1024.txt');
 
 var size = fs.statSync(file).size;
 
-// expect to see chunks no more than 10 bytes each.
-var expectLengths = [];
-for (var i = size; i > 0; i -= 10) {
-  expectLengths.push(Math.min(i, 10));
-}
+var expectLengths = [1024];
 
 var util = require('util');
 var Stream = require('stream');
@@ -60,7 +56,7 @@ TestWriter.prototype.end = function(c) {
   this.emit('results', this.buffer);
 }
 
-var r = new FSReadable(file, { bufferSize: 10 });
+var r = new FSReadable(file);
 var w = new TestWriter();
 
 w.on('results', function(res) {

test/simple/test-stream2-set-encoding.js

@@ -64,9 +64,7 @@ process.nextTick(run);
 util.inherits(TestReader, R);
 
 function TestReader(n, opts) {
-  R.call(this, util._extend({
-    bufferSize: 5
-  }, opts));
+  R.call(this, opts);
 
   this.pos = 0;
   this.len = n || 100;