neft

'use strict' utils = require 'src/utils' log = require 'src/log' assert = require 'src/assert' Dict = require 'src/dict' List = require 'src/list' log = log.scope 'Binding' {isArray} = Array MAX_LOOPS = 50 getPropHandlerName = do -> cache = Object.create null (prop) -> cache[prop] ||= "on#{utils.capitalize(prop)}Change" class Connection pool = [] @factory = (binding, item, prop, parent=null) -> if pool.length > 0 and (elem = pool.pop()) Connection.call elem, binding, item, prop, parent elem else new Connection binding, item, prop, parent constructor: (@binding, item, @prop, @parent) -> @handlerName = getPropHandlerName @prop @isConnected = false if isArray(item) @itemId = '' @child = Connection.factory @binding, item[0], item[1], @ @item = @child.getValue() else @itemId = item @child = null @item = @binding.getItemById item @connect() Object.seal @ getSignalChangeListener: do -> withParent = (prop, val) -> # TODO: provide special signal emitted with property changed if val is undefined or typeof prop isnt 'string' or @parent.prop is prop @parent.updateItem() return noParent = -> @binding.update() return withParentOnDict = (prop) -> if @prop is prop @parent.updateItem() return noParentOnDict = (prop) -> if @prop is prop @binding.update() return -> if @item instanceof Dict if @parent withParentOnDict else noParentOnDict else if @parent withParent else noParent update: -> @getSignalChangeListener().call @ connect: -> {item} = @ if item if item instanceof Dict @isConnected = true item.onChange @getSignalChangeListener(), @ else if item instanceof List @isConnected = true handler = @getSignalChangeListener() item.onChange handler, @ item.onInsert handler, @ item.onPop handler, @ else if handler = item[@handlerName] @isConnected = true handler @getSignalChangeListener(), @ return disconnect: -> {item} = @ if item and @isConnected handler = @getSignalChangeListener() if item instanceof Dict item.onChange.disconnect handler, @ else if item instanceof List item.onChange.disconnect handler, @ item.onInsert.disconnect handler, @ item.onPop.disconnect handler, @ else item[@handlerName].disconnect handler, @ @isConnected = false return updateItem: -> oldVal = @item if @child val = @child.getValue() else val = @binding.getItemById @itemId if oldVal and not @isConnected @connect() oldVal = null if oldVal isnt val @disconnect() @item = val @connect() unless @parent @binding.update() if @parent @parent.updateItem() return getValue: -> if @item @item[@prop] else null destroy: -> @disconnect() @child?.destroy() pool.push @ return module.exports = class Binding @New = (binding, ctx, target) -> target ?= new Binding binding, ctx Object.seal target # connections {connections} = target for elem in binding[1] if isArray(elem) connections.push Connection.factory target, elem[0], elem[1] target constructor: (binding, @ctx) -> assert.lengthOf binding, 2 assert.isFunction binding[0] assert.isArray binding[1] # properties @func = binding[0] @args = null @connections ||= [] # update `//<development>` @updatePending = false @updateLoop = 0 `//</development>` getItemById: (item) -> throw "Not implemented" getValue: -> throw "Not implemented" getDefaultValue: -> switch typeof @getValue() when 'string' '' when 'number' 0 when 'boolean' false else null setValue: (val) -> throw "Not implemented" onError: (err) -> update: -> unless @args return `//<development>` if @updatePending if @updateLoop > MAX_LOOPS return if ++@updateLoop is MAX_LOOPS log.error @getLoopDetectedErrorMessage() return else @updateLoop = 0 `//</development>` result = utils.tryFunction @func, @ctx, @args if result instanceof Error @onError result result = @getDefaultValue() `//<development>` @updatePending = true `//</development>` @setValue result `//<development>` @updatePending = false `//</development>` return getLoopDetectedErrorMessage: -> "Potential loop detected" destroy: -> # destroy connections while connection = @connections.pop() connection.destroy() # clear props @args = null return