XForms:Model Concurrent Changes: Difference between revisions

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XForms:Model Concurrent Changes (view source)

Revision as of 15:45, 16 May 2006

301 bytes added , 16 May 2006

Revised thoughts

Beaufour

29

edits

@@ Line 38: / Line 38: @@
 # should any event handling in the model defer concurrent events?
 # how about "rogue" events, coming from script, etc.?
-# at least also defer rebuild?
+# also defer rebuild?
-I believe the spec. only meant for option 1) to happen. It is the common use case, and is not as intrusive a change as the other options.
+"Instance data changes performed by a set of actions do not result in
+immediate computation dependency rebuilding, recalculation, revalidate and
+form control refreshing until the termination of the outermost action handler"
+[http://www.w3.org/TR/2006/REC-xforms-20060314/slice10.html#action-action Deferred Actions in the Spec]
+Based on that, I believe:
+# we should defer rebuild too
+# both "deferred events from action" and value-changes should be deferred
 == The Event-Dispatch Queue ==
-The conclusion of the above is that the model should
+The conclusion of the above is that the _model_ should
 # be asked to perform requests for controls directly, not through events
 # be responsible for dispatching events on itself
@@ Line 54: / Line 62: @@
 The nsIModelPrivateElement should expose:
 <pre>
-requestRecalculate(in boolean force);
+requestRebuild();
-requestRevalidate(in boolean force);
+requestRecalculate();
-requestRefresh(in boolean force);
+requestRevalidate();
+requestRefresh();
 </pre>
 On a call to any of these functions the following should happen
 <pre>
-doRequest(aRequest, aForce) {
+request...() {
-  if (aForce) {
-    handleRequest(aRequest);
-    return;
-  }
    if (gDefer) {
-     eventQ.pushBack(aRequest);
+     eventQ.pushBack(the_request);
      return;
    }
    gDefer = true;
-   while (aRequest) {
-    dispatchEventFor(aRequest);
+   dispatchEventFor(the_request);
-    aRequest = eventQ.popFront();
+  // Empty the queue
+  req = eventQ.popFront();
+  while (req) {
+    dispatchEventFor(req);
    }
    gDefer = false;
@@ Line 79: / Line 88: @@
 </pre>
-The <code>force</code> parameter is needed for action elements that need to bypass the event mechanism.
+&lt;recalculate&gt; and its friends and scripts call the functions directly (exposed in nsIXFormsModelElement), which bypasses both events and the queue.
 [[User:Beaufour|Beaufour]] 02:10, 16 May 2006 (PDT)