58 lines
1.7 KiB
JavaScript
58 lines
1.7 KiB
JavaScript
const fs = require('fs')
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const debug = require('debug')
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const logger = debug('serialport/bindings/unixRead')
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const { promisify } = require('util')
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const readAsync = promisify(fs.read)
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const readable = binding => {
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return new Promise((resolve, reject) => {
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binding.poller.once('readable', err => (err ? reject(err) : resolve()))
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})
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}
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const unixRead = async ({ binding, buffer, offset, length, fsReadAsync = readAsync }) => {
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logger('Starting read')
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if (!binding.isOpen) {
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const err = new Error('Port is not open')
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err.canceled = true
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throw err
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}
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try {
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const { bytesRead } = await fsReadAsync(binding.fd, buffer, offset, length, null)
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if (bytesRead === 0) {
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return unixRead({ binding, buffer, offset, length, fsReadAsync })
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}
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logger('Finished read', bytesRead, 'bytes')
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return { bytesRead, buffer }
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} catch (err) {
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logger('read error', err)
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if (err.code === 'EAGAIN' || err.code === 'EWOULDBLOCK' || err.code === 'EINTR') {
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if (!binding.isOpen) {
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const err = new Error('Port is not open')
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err.canceled = true
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throw err
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}
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logger('waiting for readable because of code:', err.code)
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await readable(binding)
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return unixRead({ binding, buffer, offset, length, fsReadAsync })
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}
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const disconnectError =
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err.code === 'EBADF' || // Bad file number means we got closed
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err.code === 'ENXIO' || // No such device or address probably usb disconnect
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err.code === 'UNKNOWN' ||
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err.errno === -1 // generic error
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if (disconnectError) {
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err.disconnect = true
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logger('disconnecting', err)
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}
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throw err
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}
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}
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module.exports = unixRead
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