ses sloppyGlobals mini kernel

experiment1.js

const test = require('tape-promise').default(require('tape'))

const SES = require('../lib/ses.umd.js')

const realm = SES.makeSESRootRealm()

test(async t => {
  const globalStore = {}

  runModuleA()
  runModuleB()

  function runModuleA () {
    const code = `
    abc = true
    `
    const config = {
      globals: {
        'abc': 'write',
      }
    }
    evaluateModule(code, config, globalStore)
  }

  function runModuleB () {
    const code = `
    xyz = abc
    `
    const config = {
      globals: {
        'abc': 'read',
        'xyz': 'write',
        'process': 'read',
      }
    }
    evaluateModule(code, config, globalStore)
  }
})

function evaluateModule (code, config, globalStore) {
  const { globalsWriteProxy, globalsReadProxy } = createGlobalsProxies(globalStore, config)
  realm.evaluate(code, globalsReadProxy, { sloppyGlobals: globalsWriteProxy })
}

function createGlobalsProxies (globalStore, config) {
  const globalsWriteProxy = new Proxy({}, {
    // reads
    has (_, key) {
      console.log('globalWrite: has', key)
      if (config.globals[key] !== 'write') return false
      return key in globalStore
    },
    ownKeys (_) {
      console.log('globalWrite: ownKeys')
      return Object.entries(config.globals)
        .filter(([key, value]) => value === 'write')
        .map(([key]) => key)
    },
    get (_, key) {
      console.log('globalWrite: get', key)
      return globalStore[key]
    },
    getOwnPropertyDescriptor (_, key) {
      console.log('globalWrite: getOwnPropertyDescriptor', key)
      return Reflect.getOwnPropertyDescriptor(globalStore, key)
    },
    // writes
    set (_, key, value) {
      console.log('globalWrite: set', key)
      if (config.globals[key] !== 'write') return false
      globalStore[key] = value
      return true
    },
    defineProperty (_, key, propDescriptor) {
      console.log('globalWrite: defineProperty', key, propDescriptor)
      if (config.globals[key] !== 'write') return false
      globalStore[key] = value
      Reflect.defineProperty(globalStore, key, propDescriptor)
      return true
    },
  })
  
  const globalsReadProxy = new Proxy({}, {
    // reads
    has (_, key) {
      console.log('globalRead: has', key)
      if (!config.globals[key]) return false
      return key in globalStore || key in global
    },
    ownKeys (_) {
      console.log('globalRead: ownKeys')
      return Reflect.ownKeys(config.globals)
    },
    get (_, key) {
      console.log('globalRead: get', key)
      if (!config.globals[key]) return undefined
      return key in globalStore ? globalStore[key] : global[key]
    },
    getOwnPropertyDescriptor (_, key) {
      console.log('globalRead: getOwnPropertyDescriptor', key)
      if (!config.globals[key]) return undefined
      const propDescriptor = Reflect.getOwnPropertyDescriptor(globalStore, key) || 
        Reflect.getOwnPropertyDescriptor(global, key)
      return propDescriptor
    },
    // writes
    set (_, key, value) {
      console.log('globalRead: set', key, value)
      return false
    },
    defineProperty (_, key, propDescriptor) {
      console.log('globalRead: defineProperty', key, propDescriptor)
      return false
    },
  })
  
  return { globalsWriteProxy, globalsReadProxy }

}

experiment2.js

const test = require('tape-promise').default(require('tape'))
const SES = require('../lib/ses.umd.js')

const realm = SES.makeSESRootRealm()


test(async t => {
  const globalStore = {}

  runModuleA()
  runModuleB()

  function runModuleA () {
    const code = `
    abc = true
    `
    const config = {
      globals: {
        'abc': 'write',
      }
    }
    evaluateModule(code, config, globalStore)
  }

  function runModuleB () {
    const code = `
    xyz = abc
    process.env
    `
    const config = {
      globals: {
        'abc': 'read',
        'xyz': 'write',
        'process': 'read',
      }
    }
    evaluateModule(code, config, globalStore)
  }
})

function evaluateModule (code, config, globalStore) {
  const globalsProxy = createGlobalsProxies(globalStore, config)
  realm.evaluate(code, {}, { sloppyGlobals: globalsProxy })
}

function createGlobalsProxies (globalStore, config) {
  const globalsProxy = new Proxy({}, {
    // reads
    has (_, key) {
      console.log('globalWrite: has', key)
      if (!(key in config.globals)) return false
      return key in globalStore || key in global
    },
    ownKeys (_) {
      console.log('globalWrite: ownKeys')
      return [...Reflect.ownKeys(config.globals), ...Reflect.ownKeys(global)]
    },
    get (_, key) {
      console.log('globalWrite: get', key)
      if (!(key in config.globals)) return undefined
      return key in globalStore ? globalStore[key] : global[key] 
    },
    getOwnPropertyDescriptor (_, key) {
      if (!(key in config.globals)) return undefined
      console.log('globalWrite: getOwnPropertyDescriptor', key)
      return key in globalStore ? Reflect.getOwnPropertyDescriptor(globalStore, key) : Reflect.getOwnPropertyDescriptor(global, key)
    },
    // writes
    set (_, key, value) {
      console.log('globalWrite: set', key)
      if (config.globals[key] !== 'write') return false
      globalStore[key] = value
      return true
    },
    defineProperty (_, key, propDescriptor) {
      console.log('globalWrite: defineProperty', key, propDescriptor)
      if (config.globals[key] !== 'write') return false
      Reflect.defineProperty(globalStore, key, propDescriptor)
      return true
    },
  })

  return globalsProxy
}