const clearObject = require('object-clear') const clone = require('clone') const EventEmitter = require('events') const PortManager = require('./portManager.js') module.exports = class Kernel extends EventEmitter { constructor (opts) { super() this.state = opts.state this.entryPort = opts.entryPort this.hypervisor = opts.hypervisor this.vmState = 'idle' this.ticks = 0 // create the port manager this.ports = new PortManager({ kernel: this, hypervisor: opts.hypervisor, state: opts.state, entryPort: opts.entryPort, parentPort: opts.parentPort }) this.vm = new opts.VM(this) this._waitingMap = new Map() this.on('result', this._runNextMessage) this.on('idle', () => { for (const [, waiter] of this._waitingMap) { waiter.resolve(this.ticks) } }) } start () { return this.ports.start() } queue (message) { message._hops++ this.ports.queue(message) if (this.vmState !== 'running') { this._updateVmState('running') this._runNextMessage() } } _updateVmState (vmState, message) { this.vmState = vmState this.emit(vmState, message) } async _runNextMessage () { const message = await this.ports.getNextMessage() if (message) { // run the next message this.run(message) } else { // if no more messages then shut down this._updateVmState('idle') } } /** * run the kernels code with a given enviroment * The Kernel Stores all of its state in the Environment. The Interface is used * to by the VM to retrive infromation from the Environment. */ async run (message) { const oldState = clone(this.state, false, 3) let result try { result = await this.vm.run(message) || {} } catch (e) { // revert the state clearObject(this.state) Object.assign(this.state, oldState) result = { exception: true, exceptionError: e } } this.emit('result', result) return result } // returns a promise that resolves once the kernel hits the threshould tick // count wait (threshold, fromPort) { if (threshold <= this.ticks) { return this.ticks } else if (this.vmState === 'idle') { return this.ports.wait(threshold, fromPort) } else { return new Promise((resolve, reject) => { this._waitingMap.set(fromPort, { threshold: threshold, resolve: resolve, from: fromPort }) }) } } incrementTicks (count) { this.ticks += count for (const [fromPort, waiter] of this._waitingMap) { if (waiter.threshold < this.ticks) { this._waitingMap.delete(fromPort) waiter.resolve(this.ticks) } } } async send (portRef, message) { message._fromPort = this.entryPort message._fromPortTicks = this.ticks const vm = await this.hypervisor.getInstance(portRef, true, this.entryPort) vm.queue(message) const waiter = this._waitingMap.get(portRef) if (waiter) { waiter.resolve(this.ticks) this._waitingMap.delete(portRef) } } }