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metamask-extension/app/scripts/lib/port-stream.js

64 lines
1.4 KiB
JavaScript

const Duplex = require('readable-stream').Duplex
const inherits = require('util').inherits
module.exports = PortDuplexStream
inherits(PortDuplexStream, Duplex)
function PortDuplexStream (port) {
Duplex.call(this, {
objectMode: true,
})
this._port = port
port.onMessage.addListener(this._onMessage.bind(this))
port.onDisconnect.addListener(this._onDisconnect.bind(this))
}
// private
PortDuplexStream.prototype._onMessage = function (msg) {
if (Buffer.isBuffer(msg)) {
delete msg._isBuffer
var data = new Buffer(msg)
// console.log('PortDuplexStream - saw message as buffer', data)
this.push(data)
} else {
// console.log('PortDuplexStream - saw message', msg)
this.push(msg)
}
}
PortDuplexStream.prototype._onDisconnect = function () {
try {
this.push(null)
} catch (err) {
this.emit('error', err)
}
}
// stream plumbing
PortDuplexStream.prototype._read = noop
PortDuplexStream.prototype._write = function (msg, encoding, cb) {
try {
if (Buffer.isBuffer(msg)) {
var data = msg.toJSON()
data._isBuffer = true
// console.log('PortDuplexStream - sent message as buffer', data)
this._port.postMessage(data)
} else {
// console.log('PortDuplexStream - sent message', msg)
this._port.postMessage(msg)
}
} catch (err) {
// console.error(err)
return cb(new Error('PortDuplexStream - disconnected'))
}
cb()
}
// util
function noop () {}