80 lines
1.8 KiB
JavaScript
80 lines
1.8 KiB
JavaScript
"use strict";
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const fs = require('fs'),
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EventEmitter = require('events'),
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Epoll = require('epoll').Epoll
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const GPIO_ROOT_PATH = '/sys/class/gpio/'
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class Interrupt extends EventEmitter {
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// bus is i2c-bus bus object
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constructor(pin_number, opts = {}) {
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super()
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this.num = pin_number;
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this.hook = opts.hook // will be passed back with the emit
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this.path = GPIO_ROOT_PATH + 'gpio' + this.num + '/'
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this.edge = opts.edge ? opts.edge : 'falling'
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this.debounce = opts.debounce ? opts.debounce : 200
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this.poller = new Epoll(function (err, fd, events) {
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if (err) { this.emit('error', err) }
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this.clear()
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this.emit('fired', this.hook)
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}.bind(this))
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}
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init() {
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try {
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if (fs.existsSync(this.path)) { this.exit() }
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fs.writeFileSync(GPIO_ROOT_PATH + 'export', this.gpio);
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fs.writeFileSync(this.path + 'direction', 'in');
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fs.writeFileSync(this.path + 'edge', this.edge);
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this.valueFd = fs.openSync(this.path + 'value', 'r+'); // Cache fd for performance.
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this.clear();
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this.start()
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process.on('SIGINT', function () {
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console.log('\ncleaning up interrupt before exiting')
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this.exit();
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})
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} catch (err) { return Promise.reject(err) }
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return Promise.resolve('interrupt ready')
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}
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fire(name = 'fired') {
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this.emit(name, this.hook)
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}
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clear() {
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fs.readSync(this.valuefd, null, 0, 1, 0);
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}
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exit() {
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if (this.valuefd) {
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this.stop()
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fs.closeSync(this.valueFd)
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}
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try {
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fs.writeFileSync(GPIO_ROOT_PATH + 'unexport', this.gpio);
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} catch (ignore) {}
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}
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start() {
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this.poller.add(this.valuefd, Epoll.EPOLLPRI);
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}
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stop() {
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this.poller.remove(this.valuefd).close();
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}
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}
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module.exports = {
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Interrupt
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}
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