#9 start the worker/pool class

bin/worker

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+#!/usr/bin/env node
+'use strict';

src/worker.js

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+/*!
+ * Copyright (C) 2016 Glayzzle (BSD3 License)
+ * @authors https://github.com/glayzzle/php-reflection/graphs/contributors
+ * @url http://glayzzle.com
+ */
+var cp = require('child_process');
+var numCPUs = require('os').cpus().length;
+var workers = [];
+
+/**
+ * @constructor
+ */
+var Worker = function worker(script) {
+    this.jobs = {};
+    this.length = 0;
+    this.script = script;
+    this.ready = true;
+    this.restart();
+};
+
+/**
+ * Worker is down and may be restarted
+ */
+Worker.prototype.restart = function(code) {
+    if (this.ready) {
+        this.ready = false;
+        if (this.child) {
+            this.child.removeAllListeners('error');
+            this.child.removeAllListeners('close');
+            this.child.removeAllListeners('exit');
+            // kill it (in case of hanging)
+            this.child.kill('SIGKILL');
+        }
+        this.child = cp.fork(this.script);
+        this.child.on('error', this.restart.bind(this));
+        this.child.on('close', this.restart.bind(this));
+        this.child.on('exit', this.restart.bind(this));
+        this.child.on('message', this.message.bind(this));
+        this.ready = true;
+
+        // retry pending scripts
+        if (this.length > 0) {
+            for(var k in this.jobs) {
+                this.child.send({
+                    filename: k,
+                    crc32: this.jobs[k].crc32
+                });
+            }
+        }
+    }
+};
+
+/**
+ * Receives the result
+ */
+Worker.prototype.message = function(data) {
+    var filename = data.filename;
+    if (this.jobs.hasOwnProperty(filename)) {
+        var promise = this.jobs[filename];
+        delete this.jobs[filename];
+        this.length--;
+        if (data.error) {
+            promise.reject(data.error);
+        } else {
+            promise.done(data);
+        }
+    }
+};
+
+/**
+ * Runs a process
+ */
+Worker.prototype.process = function(filename, crc32) {
+    if (!this.jobs.hasOwnProperty(filename)) {
+        this.length ++;
+        var self = this;
+        this.jobs[filename] = new Promise(function(done, reject) {
+            self.jobs[filename].done = done;
+            self.jobs[filename].reject = reject;
+            self.jobs[filename].crc32 = crc32;
+            self.child.send({
+                filename: filename,
+                crc32: crc32
+            });
+        });
+    }
+    return this.jobs[filename];
+};
+
+for(var i = 0; i < numCPUs; i++) {
+    workers.push(new Worker(__dirname + '/../bin/worker'));
+}
+
+/**
+ * Launch the parsing of the specified file
+ * @param {String} filename
+ * @param {String} crc32
+ * @return {Promise}
+ */
+module.exports = function(filename, crc32) {
+    var w = workers[0];
+    for(var i = 1; i < workers.length; i++) {
+        if (workers[i].ready && workers[i].length < w.length) {
+            w = workers[i];
+        }
+    }
+    return w.process(filename, crc32);
+};