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'use strict';
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const common = require('../common');
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var assert = require('assert');
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var Readable = require('_stream_readable');
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var len = 0;
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var chunks = new Array(10);
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for (var i = 1; i <= 10; i++) {
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chunks[i - 1] = Buffer.allocUnsafe(i);
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len += i;
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}
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var test = new Readable();
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var n = 0;
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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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test._read = function(size) {
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var chunk = chunks[n++];
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setTimeout(function() {
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test.push(chunk === undefined ? null : chunk);
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});
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};
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test.on('end', thrower);
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function thrower() {
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throw new Error('this should not happen!');
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}
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var bytesread = 0;
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test.on('readable', function() {
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var b = len - bytesread - 1;
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var res = test.read(b);
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if (res) {
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bytesread += res.length;
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console.error('br=%d len=%d', bytesread, len);
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setTimeout(next);
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}
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test.read(0);
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});
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test.read(0);
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function next() {
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// now let's make 'end' happen
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test.removeListener('end', thrower);
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test.on('end', common.mustCall(function() {}));
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// one to get the last byte
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var r = test.read();
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assert(r);
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assert.equal(r.length, 1);
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r = test.read();
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assert.equal(r, null);
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}
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