started experimenting with diff...

Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>

ui (gen4)/features/diff.js

@@ -0,0 +1,113 @@
+/**********************************************************************
+* 
+*
+*
+**********************************************************************/
+((typeof define)[0]=='u'?function(f){module.exports=f(require)}:define)
+(function(require){ var module={} // make module AMD/node compatible...
+/*********************************************************************/
+
+// XXX get actual diff path...
+var diff = require('lib/diff')
+
+var actions = require('lib/actions')
+var features = require('lib/features')
+
+var core = require('features/core')
+
+
+
+/*********************************************************************/
+
+// XXX get diff and save new reference state...
+var save = function(){
+	var res = this.diff()
+	this.__reference_state = this.josn()
+	return res
+}
+
+var load = function(diff){
+	// XXX
+}
+
+
+
+/*********************************************************************/
+// XXX we need a separate feature for fs stuff...
+// XXX format:
+// 		- we should separate:
+// 			.data
+// 			.images
+// 			.collections
+// 			...
+// 			should we use the same mechanics as the original save/load???
+
+var DiffActions = actions.Actions({
+	// XXX this must be read-only...
+	__reference_state: null,
+	__changes_stack: null,
+
+	diff: [`- System/`,
+		// XXX should this get separated diffs or one big diff???
+		// 		...i.e. get and arg to filter sections???
+		function(){
+			return diff.Diff(this.__reference_state, this.json()) }],
+
+	// XXX EXPERIMENTAL -- this can be another way to implement undo or 
+	// 		a way to do "pre-save manual undo points"...
+	// 		...the problem with undo is that .popChange(..) does not 
+	// 		care about what changed and how and will simply reload the 
+	// 		whole state...
+	// XXX do we need these???
+	pushChange: ['- System/',
+		core.doc`Create a save point
+		`,
+		function(){
+			var stack = this.__changes_stack = this.__changes_stack || []
+			stack.push(save.call(this))
+		}],
+	popChange: ['- System/',
+		core.doc`Restore to a save point
+		`,
+		function(n){
+			var stack = this.__changes_stack || []
+			n = n == null ? 
+					0
+				: (n == 'all' || n == '*') ? 
+					stack.length
+				: n
+			var state = this.josn()
+			stack
+				&& stack
+					.splice(-n-1)
+					.forEach(function(d){
+						state = d.unpatch(state) })
+			// XXX is this the correct way to go???
+			this.load(state)
+		}],
+
+	// XXX hook into save/load workflows...
+	// XXX
+})
+
+var Diff = 
+module.Diff = core.ImageGridFeatures.Feature({
+	title: '',
+	doc: '',
+
+	// XXX
+	tag: 'diff',
+	depends: [
+		// XXX
+	],
+
+	actions: FeatureActions, 
+
+	handlers: [],
+})
+
+
+
+
+/**********************************************************************
+* vim:set ts=4 sw=4 :                               */ return module })