web client: eliminate race condition in validation

1 files changed, 22 insertions, 23 deletions

diff --git a/web/client.js b/web/client.js
index ae2546b..7072e4c 100644
--- a/web/client.js
+++ b/web/client.js
@@ -87,16 +87,11 @@ $(function() {
 
 			var mpath = join(path, name);
 			var value = data.data[name];
-			
-			var prevTask;
-			if (mpath in invalid)
-			    prevTask = invalid[mpath][1];
-			if (!prevTask) {
-			    prevTask = $.Deferred();
-			    prevTask.resolve();
-			}
-			
-			prevTask.always(function() {
+
+			var tn = _.isObject(newValue);
+			var npv = tn ? mpath : newValue;
+
+			function validate() {
 			    var options;
 			    if (newValue != null)
 				options = {
@@ -119,22 +114,18 @@ $(function() {
 				return;
 			    }
 			    
-			    var task = objRequest(mpath, options);
-
-			    var tn = _.isObject(newValue);
-			    if (tn) newValue = mpath;
-			    invalid[mpath] = [newValue, task];
-
- 			    task.done(function() {
+ 			    objRequest(mpath, options).done(function() {
 				if (!(mpath in changed))
 				    changed[mpath] = [value];
-				if (newValue == changed[mpath][0])
+				if (!tn && newValue == changed[mpath][0])
 				    delete changed[mpath];
-				else changed[mpath][1] = newValue;
+				else changed[mpath][1] = npv;
 
-				delete invalid[mpath];
-
-				function resolve() { def.resolve(isValid()); }
+				function resolve() {
+				    var latest = invalid[mpath][1];
+				    if (latest == def) delete invalid[mpath];
+				    def.resolve(isValid());
+				}
 
 				if (tn) query(mpath).done(function(data) {
 				    if (data.meta.type == "model")
@@ -157,7 +148,15 @@ $(function() {
 				else resolve();
 				
 			    }).fail(function(xhr) { def.reject(xhr); });
-			});
+			}
+
+			var prevTask;
+			if (mpath in invalid) prevTask = invalid[mpath][1];
+
+			invalid[mpath] = [npv, def];
+
+			if (prevTask) prevTask.always(validate);
+			else validate();
 
 			return def;
 		    };