kanji-sheets/grabKanji/node_modules/readable-stream/lib/internal/streams/pipeline.js

97 lines
2.4 KiB
JavaScript

// Ported from https://github.com/mafintosh/pump with
// permission from the author, Mathias Buus (@mafintosh).
'use strict';
var eos;
function once(callback) {
var called = false;
return function () {
if (called) return;
called = true;
callback.apply(void 0, arguments);
};
}
var _require$codes = require('../../../errors').codes,
ERR_MISSING_ARGS = _require$codes.ERR_MISSING_ARGS,
ERR_STREAM_DESTROYED = _require$codes.ERR_STREAM_DESTROYED;
function noop(err) {
// Rethrow the error if it exists to avoid swallowing it
if (err) throw err;
}
function isRequest(stream) {
return stream.setHeader && typeof stream.abort === 'function';
}
function destroyer(stream, reading, writing, callback) {
callback = once(callback);
var closed = false;
stream.on('close', function () {
closed = true;
});
if (eos === undefined) eos = require('./end-of-stream');
eos(stream, {
readable: reading,
writable: writing
}, function (err) {
if (err) return callback(err);
closed = true;
callback();
});
var destroyed = false;
return function (err) {
if (closed) return;
if (destroyed) return;
destroyed = true; // request.destroy just do .end - .abort is what we want
if (isRequest(stream)) return stream.abort();
if (typeof stream.destroy === 'function') return stream.destroy();
callback(err || new ERR_STREAM_DESTROYED('pipe'));
};
}
function call(fn) {
fn();
}
function pipe(from, to) {
return from.pipe(to);
}
function popCallback(streams) {
if (!streams.length) return noop;
if (typeof streams[streams.length - 1] !== 'function') return noop;
return streams.pop();
}
function pipeline() {
for (var _len = arguments.length, streams = new Array(_len), _key = 0; _key < _len; _key++) {
streams[_key] = arguments[_key];
}
var callback = popCallback(streams);
if (Array.isArray(streams[0])) streams = streams[0];
if (streams.length < 2) {
throw new ERR_MISSING_ARGS('streams');
}
var error;
var destroys = streams.map(function (stream, i) {
var reading = i < streams.length - 1;
var writing = i > 0;
return destroyer(stream, reading, writing, function (err) {
if (!error) error = err;
if (err) destroys.forEach(call);
if (reading) return;
destroys.forEach(call);
callback(error);
});
});
return streams.reduce(pipe);
}
module.exports = pipeline;