git ssb

1
const Message = require('primea-message')
2
const BN = require('bn.js')
3
const PortManager = require('./portManager.js')
4
const DeleteMessage = require('./deleteMessage')
5
6
module.exports = class Kernel {
7
  /**
8
   * the Kernel manages the varous message passing functions and provides
9
   * an interface for the containers to use
10
   * @param {Object} opts
11
   * @param {Object} opts.id - the UUID of the Kernel
12
   * @param {Object} opts.state - the state of the container
13
   * @param {Object} opts.hypervisor
14
   * @param {Object} opts.container - the container constuctor and argments
15
   */
16
  constructor (opts) {
17
    this.state = opts.state
18
    this.hypervisor = opts.hypervisor
19
    this.id = opts.id
20
    this.container = new opts.container.Constructor(this, opts.container.args)
21
22
    this.ticks = 0
23
    this.containerState = 'idle'
24
25
    // create the port manager
26
    this.ports = new PortManager(Object.assign({
27
      kernel: this
28
    }, opts))
29
  }
30
31
  /**
32
   * adds a message to this containers message queue
33
   * @param {string} portName
34
   * @param {object} message
35
   */
36
  queue (portName, message) {
37
    this.ports.queue(portName, message)
38
    if (this.containerState !== 'running') {
39
      this.containerState = 'running'
40
      return this._runNextMessage()
41
    }
42
  }
43
44
  initialize (message) {
45
    this.containerState = 'running'
46
    return this.run(message, 'initialize')
47
  }
48
49
  // waits for the next message
50
  async _runNextMessage () {
51
    // check if the ports are saturated, if so we don't have to wait on the
52
    // scheduler
53
    const message = await this.ports.getNextMessage()
54
55
    if (message) {
56
      message.fromPort.messages.shift()
57
      // if the message we recived had more ticks then we currently have the
58
      // update it
59
      if (message._fromTicks > this.ticks) {
60
        this.ticks = message._fromTicks
61
        this.hypervisor.scheduler.update(this)
62
      }
63
      // run the next message
64
      return this.run(message)
65
    } else {
66
      // if no more messages then shut down
67
      this.hypervisor.scheduler.done(this.id)
68
    }
69
  }
70
71
  /**
72
   * run the kernels code with a given enviroment
73
   * @param {object} message - the message to run
74
   * @param {boolean} init - whether or not to run the intialization routine
75
   * @returns {Promise}
76
   */
77
  async run (message, method = 'run') {
78
    let result
79
80
    const responsePort = message.responsePort
81
    delete message.responsePort
82
83
    this.ports.addReceivedPorts(message)
84
    message._hops++
85
86
    if (message.constructor === DeleteMessage) {
87
      this.ports._delete(message.fromName)
88
    } else {
89
      try {
90
        result = await this.container[method](message) || {}
91
      } catch (e) {
92
        result = {
93
          exception: true,
94
          exceptionError: e
95
        }
96
      }
97
    }
98
99
    if (responsePort) {
100
      this.send(responsePort, new Message({
101
        data: result
102
      }))
103
      this.ports._unboundPorts.add(responsePort)
104
    }
105
106
    this.ports.clearUnboundedPorts()
107
    return this._runNextMessage()
108
  }
109
110
  getResponsePort (message) {
111
    if (message.responsePort) {
112
      return message.responsePort.destPort
113
    } else {
114
      const [portRef1, portRef2] = this.ports.createChannel()
115
      message.responsePort = portRef2
116
      this.ports._unboundPorts.delete(portRef2)
117
      return portRef1
118
    }
119
  }
120
121
  /**
122
   * updates the number of ticks that the container has run
123
   * @param {Number} count - the number of ticks to add
124
   */
125
  incrementTicks (count) {
126
    this.ticks += count
127
    this.hypervisor.scheduler.update(this)
128
  }
129
130
  /**
131
   * creates a new message
132
   * @param {*} data
133
   */
134
  createMessage (opts) {
135
    const message = new Message(opts)
136
    this.ports.checkSendingPorts(message)
137
    return message
138
  }
139
140
  /**
141
   * creates a new container. Returning a port to it.
142
   * @param {String} type
143
   * @param {*} data - the data to populate the initail state with
144
   * @returns {Object}
145
   */
146
  createInstance (type, message) {
147
    let nonce = this.state.nonce
148
149
    const id = {
150
      nonce: nonce,
151
      parent: this.id
152
    }
153
154
    // incerment the nonce
155
    nonce = new BN(nonce)
156
    nonce.iaddn(1)
157
    this.state.nonce = nonce.toArray()
158
    this.ports.removeSentPorts(message)
159
160
    return this.hypervisor.createInstance(type, message, id)
161
  }
162
163
  /**
164
   * sends a message to a given port
165
   * @param {Object} portRef - the port
166
   * @param {Message} message - the message
167
   */
168
  async send (port, message) {
169
    // set the port that the message came from
170
    message._fromTicks = this.ticks
171
    this.ports.removeSentPorts(message)
172
173
    // if (this.currentMessage !== message && !message.responsePort) {
174
    //   this.currentMessage._addSubMessage(message)
175
    // }
176
177
    if (port.destId) {
178
      const id = port.destId
179
      const instance = await this.hypervisor.getInstance(id)
180
      return instance.queue(port.destName, message)
181
    } else {
182
      // port is unbound
183
      port.destPort.messages.push(message)
184
    }
185
  }
186
}
187