Merge pull request #240 from mikeric/full-keypath-observers

Full Keypath Observers

@@ -20,7 +20,7 @@ module.exports = (grunt) ->
             'src/view.coffee'
             'src/bindings.coffee'
             'src/parsers.coffee'
-            'src/keypath_observer.coffee'
+            'src/observer.coffee'
             'src/binders.coffee'
             'src/adapters.coffee'
             'src/export.coffee'

@@ -8,7 +8,7 @@ describe('Rivets.Binding', function() {
     el = document.createElement('div');
     el.setAttribute('data-text', 'obj.name');
 
-    view = rivets.bind(el, {obj: {}});
+    view = rivets.bind(el, {obj: {name: 'test'}});
     binding = view.bindings[0];
     model = binding.model;
   });
@@ -40,12 +40,10 @@ describe('Rivets.Binding', function() {
         rivets.config.preloadData = true;
       });
 
-      it('sets the initial value via the adapter', function() {
+      it('sets the initial value', function() {
         spyOn(binding, 'set');
-        spyOn(adapter, 'read');
         binding.bind();
-        expect(adapter.read).toHaveBeenCalledWith(model, 'name');
-        expect(binding.set).toHaveBeenCalled();
+        expect(binding.set).toHaveBeenCalledWith('test');
       });
     });
 

@@ -9,8 +9,8 @@ class Rivets.Binding
   constructor: (@view, @el, @type, @keypath, @options = {}) ->
     @formatters = @options.formatters || []
     @dependencies = []
+    @model = undefined
     @setBinder()
-    @setObserver()
 
   # Sets the binder to use when binding and syncing.
   setBinder: =>
@@ -26,18 +26,6 @@ class Rivets.Binding
     @binder or= @view.binders['*']
     @binder = {routine: @binder} if @binder instanceof Function
 
-  # Sets a keypath observer that will notify this binding when any intermediary
-  # keys are changed.
-  setObserver: =>
-    @observer = new Rivets.KeypathObserver @view, @view.models, @keypath, (obs) =>
-      @unbind true if @key
-      @model = obs.target
-      @bind true if @key
-      @sync()
-
-    @key = @observer.key
-    @model = @observer.target
-
   # Applies all the current formatters to the supplied value and returns the
   # formatted value.
   formattedValue: (value) =>
@@ -70,10 +58,16 @@ class Rivets.Binding
 
   # Syncs up the view binding with the model.
   sync: =>
-    @set if @key
-      @view.adapters[@key.interface].read @model, @key.path
-    else
-      @model
+    if @model isnt @observer.target
+      observer.unobserve() for observer in @dependencies
+      @dependencies = []
+
+      if (@model = @observer.target)? and @options.dependencies?.length
+        for dependency in @options.dependencies
+          observer = new Rivets.Observer @view, @model, dependency, @sync
+          @dependencies.push observer
+
+    @set @observer.value()
 
   # Publishes the value currently set on the input element back to the model.
   publish: =>
@@ -86,42 +80,30 @@ class Rivets.Binding
       if @view.formatters[id]?.publish
         value = @view.formatters[id].publish value, args...
 
-    @view.adapters[@key.interface].publish @model, @key.path, value
+    @observer.publish value
 
   # Subscribes to the model for changes at the specified keypath. Bi-directional
   # routines will also listen for changes on the element to propagate them back
   # to the model.
-  bind: (silent = false) =>
-    @binder.bind?.call @, @el unless silent
-    @view.adapters[@key.interface].subscribe(@model, @key.path, @sync) if @key
-    @sync() if @view.config.preloadData unless silent
+  bind: =>
+    @binder.bind?.call @, @el
+    @observer = new Rivets.Observer @view, @view.models, @keypath, @sync
+    @model = @observer.target
 
-    if @options.dependencies?.length
+    if @model? and @options.dependencies?.length
       for dependency in @options.dependencies
-        observer = new Rivets.KeypathObserver @view, @model, dependency, (obs, prev) =>
-          key = obs.key
-          @view.adapters[key.interface].unsubscribe prev, key.path, @sync
-          @view.adapters[key.interface].subscribe obs.target, key.path, @sync
-          @sync()
-
-        key = observer.key
-        @view.adapters[key.interface].subscribe observer.target, key.path, @sync
+        observer = new Rivets.Observer @view, @model, dependency, @sync
         @dependencies.push observer
 
-  # Unsubscribes from the model and the element.
-  unbind: (silent = false) =>
-    unless silent
-      @binder.unbind?.call @, @el
-      @observer.unobserve()
-
-    @view.adapters[@key.interface].unsubscribe(@model, @key.path, @sync) if @key
+    @sync() if @view.config.preloadData
 
-    if @dependencies.length
-      for obs in @dependencies
-        key = obs.key
-        @view.adapters[key.interface].unsubscribe obs.target, key.path, @sync
+  # Unsubscribes from the model and the element.
+  unbind: =>
+    @binder.unbind?.call @, @el
+    @observer.unobserve()
 
-      @dependencies = []
+    observer.unobserve() for observer in @dependencies
+    @dependencies = []
 
   # Updates the binding's model from what is currently set on the view. Unbinds
   # the old model first and then re-binds with the new model.
@@ -190,7 +172,6 @@ class Rivets.TextBinding extends Rivets.Binding
   constructor: (@view, @el, @type, @keypath, @options = {}) ->
     @formatters = @options.formatters || []
     @dependencies = []
-    @setObserver()
 
   # A standard routine binder used for text node bindings.
   binder:

-# Rivets.KeypathObserver
+# Rivets.Observer
 # ----------------------
 
 # Parses and observes a full keypath with the appropriate adapters. Also
 # intelligently re-realizes the keypath when intermediary keys change.
-class Rivets.KeypathObserver
+class Rivets.Observer
   # Performs the initial parse, variable instantiation and keypath realization.
   constructor: (@view, @model, @keypath, @callback) ->
     @parse()
-    @objectPath = []
-    @target = @realize()
+    @initialize()
 
   # Parses the keypath using the interfaces defined on the view. Sets variables
   # for the tokenized keypath, as well as the end key.
@@ -25,34 +24,67 @@ class Rivets.KeypathObserver
     @tokens = Rivets.KeypathParser.parse path, interfaces, root
     @key = @tokens.pop()
 
-  # Updates the keypath. This is called when any intermediate key is changed.
+  initialize: =>
+    @objectPath = []
+    @target = @realize()
+    @set true, @key, @target, @callback if @target?
+
+  # Updates the keypath. This is called when any intermediary key is changed.
   update: =>
     unless (next = @realize()) is @target
-      prev = @target
+      @set false, @key, @target, @callback if @target?
+      @set true, @key, next, @callback if next?
+
+      oldValue = @value()
       @target = next
-      @callback @, prev
+      @callback() unless @value() is oldValue
+
+  adapter: (key) =>
+    @view.adapters[key.interface]
+
+  set: (active, key, obj, callback) =>
+    action = if active then 'subscribe' else 'unsubscribe'
+    @adapter(key)[action] obj, key.path, callback
+
+  read: (key, obj) =>
+    @adapter(key).read obj, key.path
+
+  publish: (value) =>
+    if @target?
+      @adapter(@key).publish @target, @key.path, value
+
+  value: =>
+    @read @key, @target if @target?
 
   # Realizes the full keypath, attaching observers for every key and correcting
   # old observers to any changed objects in the keypath.
   realize: =>
     current = @model
+    unreached = null
 
     for token, index in @tokens
-      if @objectPath[index]?
-        if current isnt prev = @objectPath[index]
-          @view.adapters[token.interface].unsubscribe prev, token.path, @update
-          @view.adapters[token.interface].subscribe current, token.path, @update
+      if current?
+        if @objectPath[index]?
+          if current isnt prev = @objectPath[index]
+            @set false, token, prev, @update
+            @set true, token, current, @update
+            @objectPath[index] = current
+        else
+          @set true, token, current, @update
           @objectPath[index] = current
+        
+        current = @read token, current
       else
-        @view.adapters[token.interface].subscribe current, token.path, @update
-        @objectPath[index] = current
+        unreached ?= index
 
-      current = @view.adapters[token.interface].read current, token.path
+        if prev = @objectPath[index]
+          @set false, token, prev, @update
 
+    @objectPath.splice unreached if unreached?
     current
 
   # Unobserves any current observers set up on the keys.
   unobserve: =>
     for token, index in @tokens
       if obj = @objectPath[index]
-        @view.adapters[token.interface].unsubscribe obj, token.path, @update
+        @set false, token, obj, @update