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var util = require('util');
var PassThrough = require('readable-stream/passthrough');
module.exports = {
Readable: Readable,
Writable: Writable
};
util.inherits(Readable, PassThrough);
util.inherits(Writable, PassThrough);
// Patch the given method of instance so that the callback
// is executed once, before the actual method is called the
// first time.
function beforeFirstCall(instance, method, callback) {
instance[method] = function() {
delete instance[method];
callback.apply(this, arguments);
return this[method].apply(this, arguments);
};
}
function Readable(fn, options) {
if (!(this instanceof Readable))
return new Readable(fn, options);
PassThrough.call(this, options);
beforeFirstCall(this, '_read', function() {
var source = fn.call(this, options);
var emit = this.emit.bind(this, 'error');
source.on('error', emit);
source.pipe(this);
});
this.emit('readable');
}
function Writable(fn, options) {
if (!(this instanceof Writable))
return new Writable(fn, options);
PassThrough.call(this, options);
beforeFirstCall(this, '_write', function() {
var destination = fn.call(this, options);
var emit = this.emit.bind(this, 'error');
destination.on('error', emit);
this.pipe(destination);
});
this.emit('writable');
}
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