noflo-lift/components/Assembler.coffee

Lift Packets for Processing in NoFlo

noflo = require("noflo")
_ = require("underscore")
_s = require("underscore.string")
{ CacheStorage } = require("nohoarder")

class Assembler extends noflo.Component

  description: _s.clean "given a data structure, a pattern, and a
  sub-structure, replace a subset of the data structure as specified by
  the pattern with the sub-structure"

  constructor: ->
    @cache = new CacheStorage
    @patterns = []

    @inPorts =
      in: new noflo.Port
      pattern: new noflo.Port
      replacement: new noflo.Port
    @outPorts =
      out: new noflo.Port

    @inPorts.pattern.on "connect", =>
      @patterns = []

    @inPorts.pattern.on "data", (pattern) =>
      @patterns.push new RegExp pattern

    @inPorts.replacement.on "connect", =>
      @cache.connect()

    @inPorts.replacement.on "begingroup", (group) =>
      @cache.beginGroup(group)

    @inPorts.replacement.on "data", (data) =>
      @cache.send(data)

    @inPorts.replacement.on "endgroup", (group) =>
      @cache.endGroup(group)

    @inPorts.replacement.on "disconnect", =>
      @cache.disconnect()

    @inPorts.in.on "connect", =>
      # Whether the group pattern has matched before, regardless whether
      # it's matching now or not
      @hasMatched = false
      @groups = []

    @inPorts.in.on "begingroup", (group) =>
      @outPorts.out.beginGroup(group) unless @matchPattern()

      @groups.push(group)

      if @matchPattern() and not @hasMatched
        @hasMatched = true
        @cache.flushCache(@outPorts.out)
        @cache.reset()

    @inPorts.in.on "data", (data) =>
      @outPorts.out.send(data) unless @matchPattern()

    @inPorts.in.on "endgroup", (group) =>
      @groups.pop()

      @outPorts.out.endGroup() unless @matchPattern()

    @inPorts.in.on "disconnect", =>
      @outPorts.out.disconnect()

  matchPattern: ->
    groups = @groups.slice(0, @patterns.length)

    for p, i in @patterns
      return false unless groups[i]?.match(p)?

    return true

exports.getComponent = -> new Assembler