git ssb

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const Vertex = require('./deps/kernelVertex')
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// The Kernel Exposes this Interface to VM instances it makes
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const Interface = require('./interface.js')
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const InterfaceAPI = require('./interfaceAPI.js')
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const Environment = require('./environment.js')
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module.exports = class Kernel {
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  constructor (opts = {}) {
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    this.state = opts.state || new Vertex()
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    this.parent = opts.parent
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    // if code is bound to this kernel then create the interfaceAPI and the
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    // imports
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    if (opts.code) {
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      this.interfaceAPI = new InterfaceAPI(opts.code)
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      this.imports = this.buildImports(opts.interfaces)
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    }
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  }
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  /**
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   * Builds a import map with an array of given interfaces
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   */
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  buildImports (interfaces = [Interface]) {
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    return interfaces.reduce((obj, Interface) => {
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      obj[Interface.name] = new Interface(this.interfaceAPI).exports
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      return obj
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    }, {})
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  }
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  /**
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   * run the kernels code with a given enviroment
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   * The Kernel Stores all of its state in the Environment. The Interface is used
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   * to by the VM to retrive infromation from the Environment.
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   */
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  async run (environment = new Environment({state: this.state}), imports = this.imports) {
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    await this.interfaceAPI.run(environment, imports)
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    return environment
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  }
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  async messageReceiver (message) {
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    // let the code handle the message if there is code
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    if (this.code) {
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      const environment = new Environment(message)
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      let result = await this.run(environment)
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      if (!result.execption) {
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        this.state = result.state
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      }
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    } else if (message.to.length) {
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      // else forward the message on to the destination contract
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      let [vertex, done] = await this.state.update(message.to)
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      message.to = []
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      await vertex.kernel.messageReceiver(message)
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      done(vertex)
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    }
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  }
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  copy () {
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    return new Kernel({
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      state: this.state.copy(),
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      code: this.code,
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      interfaces: this.interfaces,
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      parent: this.parent
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    })
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  }
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}
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