Files: 1585b228b98ee11398442d6ae9697882ea7360dd / kernel.js
4680 bytesRaw
1 | const PriorityQueue = require('fastpriorityqueue') |
2 | const EventEmitter = require('events') |
3 | const BN = require('bn.js') |
4 | const PortManager = require('./portManager.js') |
5 | |
6 | module.exports = class Kernel extends EventEmitter { |
7 | constructor (opts) { |
8 | super() |
9 | this.state = opts.state |
10 | this.entryPort = opts.entryPort |
11 | this.hypervisor = opts.hypervisor |
12 | |
13 | this.vmState = 'idle' |
14 | this.ticks = 0 |
15 | // create the port manager |
16 | this.ports = new PortManager({ |
17 | kernel: this, |
18 | hypervisor: opts.hypervisor, |
19 | ports: opts.state.ports, |
20 | entryPort: opts.entryPort, |
21 | parentPort: opts.parentPort |
22 | }) |
23 | |
24 | this.vm = new opts.VM(this) |
25 | this._waitingQueue = new PriorityQueue((a, b) => { |
26 | return a.threshold > b.threshold |
27 | }) |
28 | this.on('result', this._runNextMessage) |
29 | this.on('idle', () => { |
30 | while (!this._waitingQueue.isEmpty()) { |
31 | this._waitingQueue.poll().resolve() |
32 | } |
33 | }) |
34 | } |
35 | |
36 | start () { |
37 | return this.ports.start() |
38 | } |
39 | |
40 | queue (message) { |
41 | this.ports.queue(message) |
42 | if (this.vmState !== 'running') { |
43 | this._updateVmState('running') |
44 | this._runNextMessage() |
45 | } |
46 | } |
47 | |
48 | _updateVmState (vmState, message) { |
49 | this.vmState = vmState |
50 | this.emit(vmState, message) |
51 | } |
52 | |
53 | async _runNextMessage () { |
54 | const message = await this.ports.getNextMessage() |
55 | // if the vm is paused and it gets a message; save that message for use when the VM is resumed |
56 | if (message && this.vmState === 'paused') { |
57 | this.ports._portMap(message._fromPort).unshfit(message) |
58 | } else if (!message && this.vmState !== 'paused') { |
59 | // if no more messages then shut down |
60 | this._updateVmState('idle') |
61 | } else { |
62 | // run the next message |
63 | this._run(message) |
64 | } |
65 | } |
66 | |
67 | _updateEntryPort (entryPort) { |
68 | // reset waits, update parent port |
69 | } |
70 | |
71 | destroy () { |
72 | // destory waits |
73 | } |
74 | |
75 | pause () { |
76 | this._setState('paused') |
77 | } |
78 | |
79 | resume () { |
80 | this._setState('running') |
81 | this._runNextMessage() |
82 | } |
83 | |
84 | /** |
85 | * run the kernels code with a given enviroment |
86 | * The Kernel Stores all of its state in the Environment. The Interface is used |
87 | * to by the VM to retrive infromation from the Environment. |
88 | */ |
89 | async _run (message) { |
90 | // shallow copy |
91 | const oldState = Object.assign({}, this.state) |
92 | let result |
93 | try { |
94 | result = await this.vm.run(message) || {} |
95 | } catch (e) { |
96 | result = { |
97 | exception: true, |
98 | exceptionError: e |
99 | } |
100 | clearObject(this.state) |
101 | Object.assign(this.state, oldState) |
102 | } |
103 | |
104 | this.emit('result', result) |
105 | return result |
106 | } |
107 | |
108 | // returns a promise that resolves once the kernel hits the threshould tick |
109 | // count |
110 | async wait (threshold) { |
111 | return new Promise((resolve, reject) => { |
112 | if (this.vmState === 'idle' || threshold <= this.ticks) { |
113 | resolve(this.ticks) |
114 | } else { |
115 | this._waitingQueue.add({ |
116 | threshold: threshold, |
117 | resolve: resolve |
118 | }) |
119 | } |
120 | }) |
121 | } |
122 | |
123 | incrementTicks (count) { |
124 | this.ticks += count |
125 | while (!this._waitingQueue.isEmpty()) { |
126 | const waiter = this._waitingQueue.peek() |
127 | if (waiter.threshold > this.ticks) { |
128 | break |
129 | } else { |
130 | this._waitingQueue.poll().resolve(this.ticks) |
131 | } |
132 | } |
133 | } |
134 | |
135 | async createPort (type, name) { |
136 | const VM = this.hypervisor._VMs[type] |
137 | const parentId = this.entryPort ? this.entryPort.id : null |
138 | |
139 | const portRef = { |
140 | 'messages': [], |
141 | 'id': { |
142 | '/': { |
143 | nonce: this.state.nonce, |
144 | parent: parentId |
145 | } |
146 | }, |
147 | 'type': type, |
148 | 'link': { |
149 | '/': VM.createState() |
150 | } |
151 | } |
152 | |
153 | // create the port instance |
154 | await this.ports.set(name, portRef) |
155 | |
156 | // incerment the nonce |
157 | const nonce = new BN(this.state.nonce) |
158 | nonce.iaddn(1) |
159 | this.state.nonce = nonce.toArray() |
160 | |
161 | return portRef |
162 | } |
163 | |
164 | async send (portRef, message) { |
165 | try { |
166 | const portInstance = await this.ports.get(portRef) |
167 | portInstance.hasSent = true |
168 | } catch (e) { |
169 | throw new Error('invalid port referance, which means the port that the port was either moved or destoried') |
170 | } |
171 | const id = await this.hypervisor.generateID(this.entryPort) |
172 | message._fromPort = id |
173 | message._ticks = this.ticks |
174 | |
175 | const receiverEntryPort = portRef === this.entryPort ? this.parentPort : portRef |
176 | const vm = await this.hypervisor.getInstance(receiverEntryPort) |
177 | vm.queue(message) |
178 | if (this.vmState !== 'running') { |
179 | this._updateVmState('running') |
180 | this._runNextMessage() |
181 | } |
182 | } |
183 | } |
184 | |
185 | function clearObject (myObject) { |
186 | for (var member in myObject) { |
187 | delete myObject[member] |
188 | } |
189 | } |
190 |
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