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'use strict';
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require('../common');
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var assert = require('assert');
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var stream = require('stream');
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{
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let count = 1000;
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const source = new stream.Readable();
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stream: There is no _read cb, there is only push
This makes it so that `stream.push(chunk)` is the only way to signal the
end of reading, removing the confusing disparity between the
callback-style _read method, and the fact that most real-world streams
do not have a 1:1 corollation between the "please give me data" event,
and the actual arrival of a chunk of data.
It is still possible, of course, to implement a `CallbackReadable` on
top of this. Simply provide a method like this as the callback:
function readCallback(er, chunk) {
if (er)
stream.emit('error', er);
else
stream.push(chunk);
}
However, *only* fs streams actually would behave in this way, so it
makes not a lot of sense to make TCP, TLS, HTTP, and all the rest have
to bend into this uncomfortable paradigm.
12 years ago
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source._read = function(n) {
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n = Math.min(count, n);
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count -= n;
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source.push(Buffer.allocUnsafe(n));
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};
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let unpipedDest;
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source.unpipe = function(dest) {
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unpipedDest = dest;
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stream.Readable.prototype.unpipe.call(this, dest);
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};
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const dest = new stream.Writable();
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dest._write = function(chunk, encoding, cb) {
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cb();
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};
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source.pipe(dest);
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let gotErr = null;
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dest.on('error', function(err) {
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gotErr = err;
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});
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let unpipedSource;
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dest.on('unpipe', function(src) {
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unpipedSource = src;
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});
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const err = new Error('This stream turned into bacon.');
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dest.emit('error', err);
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assert.strictEqual(gotErr, err);
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assert.strictEqual(unpipedSource, source);
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assert.strictEqual(unpipedDest, dest);
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}
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{
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let count = 1000;
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const source = new stream.Readable();
|
stream: There is no _read cb, there is only push
This makes it so that `stream.push(chunk)` is the only way to signal the
end of reading, removing the confusing disparity between the
callback-style _read method, and the fact that most real-world streams
do not have a 1:1 corollation between the "please give me data" event,
and the actual arrival of a chunk of data.
It is still possible, of course, to implement a `CallbackReadable` on
top of this. Simply provide a method like this as the callback:
function readCallback(er, chunk) {
if (er)
stream.emit('error', er);
else
stream.push(chunk);
}
However, *only* fs streams actually would behave in this way, so it
makes not a lot of sense to make TCP, TLS, HTTP, and all the rest have
to bend into this uncomfortable paradigm.
12 years ago
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source._read = function(n) {
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n = Math.min(count, n);
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count -= n;
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source.push(Buffer.allocUnsafe(n));
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};
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let unpipedDest;
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source.unpipe = function(dest) {
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unpipedDest = dest;
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stream.Readable.prototype.unpipe.call(this, dest);
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};
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const dest = new stream.Writable();
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dest._write = function(chunk, encoding, cb) {
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cb();
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};
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source.pipe(dest);
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let unpipedSource;
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dest.on('unpipe', function(src) {
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unpipedSource = src;
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});
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const err = new Error('This stream turned into bacon.');
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let gotErr = null;
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try {
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dest.emit('error', err);
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} catch (e) {
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gotErr = e;
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}
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assert.strictEqual(gotErr, err);
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assert.strictEqual(unpipedSource, source);
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assert.strictEqual(unpipedDest, dest);
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}
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