git ssb

1
const Buffer = require('safe-buffer').Buffer
2
const Actor = require('./actor.js')
3
const Scheduler = require('./scheduler.js')
4
const { ID, decoder, generateActorId } = require('primea-objects')
5
const cbor = require('borc')
6
7
module.exports = class Hypervisor {
8
  /**
9
   * The Hypervisor manages the container instances by instantiating them and
10
   * destorying them when possible. It also facilitates localating Containers
11
   * @param {Object} opts
12
   * @param {Object} opts.tree - a [radix tree](https://github.com/dfinity/js-dfinity-radix-tree) to store the state
13
   * @param {Array} opts.container - an array of containers to regester
14
   * @param {Array} opts.drivers - an array of drivers to install
15
   * @param {boolean} [opts.meter=true] - whether to meter gas or not
16
   */
17
  constructor (opts) {
18
    opts.tree.dag.decoder = decoder
19
    this.tree = opts.tree
20
    this.scheduler = new Scheduler(this)
21
    this._containerTypes = {}
22
    this.nonce = opts.nonce || 0
23
    this.meter = opts.meter !== undefined ? opts.meter : true;
24
    (opts.containers || []).forEach(container => this.registerContainer(container));
25
    (opts.drivers || []).forEach(driver => this.registerDriver(driver))
26
  }
27
28
  /**
29
   * sends a message(s). If an array of message is given the all the messages will be sent at once
30
   * @param {Object} message - the [message](https://github.com/primea/js-primea-message) to send
31
   * @returns {Promise} a promise that resolves once the receiving container is loaded
32
   */
33
  send (messages) {
34
    if (!Array.isArray(messages)) {
35
      messages = [messages]
36
    }
37
    this.scheduler.queue(messages)
38
  }
39
40
  /**
41
   * loads an actor from the tree given its id
42
   * @param {ID} id
43
   * @returns {Promise<Actor>}
44
   */
45
  async loadActor (id) {
46
    const state = await this.tree.get(id.id)
47
    const [code, storage] = await Promise.all([
48
      this.tree.graph.get(state.node, '1'),
49
      this.tree.graph.get(state.node, '2')
50
    ])
51
    const [type, nonce] = state.value
52
    const Container = this._containerTypes[type]
53
54
    // create a new actor instance
55
    const actor = new Actor({
56
      hypervisor: this,
57
      state,
58
      Container,
59
      id,
60
      nonce,
61
      type,
62
      code,
63
      storage,
64
      tree: this.tree
65
    })
66
67
    await actor.startup()
68
    return actor
69
  }
70
71
  /**
72
   * creates an instance of an Actor
73
   * @param {Integer} type - the type id for the container
74
   * @param {Object} message - an intial [message](https://github.com/primea/js-primea-message) to send newly created actor
75
   * @param {Object} id - the id for the actor
76
   */
77
  createActor (type, code, id = {nonce: this.nonce++, parent: null}) {
78
    const Container = this._containerTypes[type]
79
    const actorId = generateActorId(id)
80
    const {modRef: module, state} = Container.onCreation(code, actorId)
81
    const metaData = [type, 0]
82
83
    // save the container in the state
84
    this.tree.set(actorId.id, metaData).then(node => {
85
      // save the code
86
      node[1] = {
87
        '/': code
88
      }
89
      // save the storage
90
      node[2] = {
91
        '/': state
92
      }
93
    })
94
95
    return {
96
      id: actorId,
97
      module
98
    }
99
  }
100
101
  /**
102
   * creates a state root starting from a given container and a given number of
103
   * ticks
104
   * @param {Number} ticks the number of ticks at which to create the state root
105
   * @returns {Promise}
106
   */
107
  async createStateRoot () {
108
    if (this.scheduler._running) {
109
      await new Promise((resolve, reject) => {
110
        this.scheduler.once('idle', resolve)
111
      })
112
    }
113
    await this.tree.set(Buffer.from([0]), this.nonce)
114
    return this.tree.flush()
115
  }
116
117
  /**
118
   * set the state root. The promise must resolve before creating or sending any more messages to the hypervisor
119
   * @param {Buffer} stateRoot
120
   * @return {Promise}
121
   */
122
  async setStateRoot (stateRoot) {
123
    this.tree.root = stateRoot
124
    const node = await this.tree.get(Buffer.from([0]))
125
    this.nonce = node.value
126
  }
127
128
  /**
129
   * regesters a container with the hypervisor
130
   * @param {Function} Constructor - the container's constuctor
131
   */
132
  registerContainer (Constructor) {
133
    this._containerTypes[Constructor.typeId] = Constructor
134
  }
135
136
  /**
137
   * register a driver with the hypervisor
138
   * @param {driver} driver
139
   */
140
  registerDriver (driver) {
141
    driver.startup(this)
142
    this.scheduler.drivers.set(driver.id.toString(), driver)
143
  }
144
}
145