Bug #252394 --> Make parsing RSS feeds asynch and report the progress on each item as we store it

to a folder back in the subscriptions UI dialog.

mail/extensions/newsblog/content/Feed.js

@@ -449,10 +449,16 @@ var gItemsToStoreIndex = 0;
 // otherwise it triggers a download done notification to the UI
 function storeNextItem()
 {
-  var item = gItemsToStore[gItemsToStoreIndex++]; 
+  var item = gItemsToStore[gItemsToStoreIndex]; 
   item.store();
   item.markValid();
 
+  // if the listener is tracking progress for storing each item, report it here...
+  if (item.feed.downloadCallback.onFeedItemStored)
+    item.feed.downloadCallback.onFeedItemStored(item.feed, gItemsToStoreIndex, gItemsToStore.length);
+ 
+  gItemsToStoreIndex++
+
   // eventually we'll report individual progress here....
 
   if (gItemsToStoreIndex < gItemsToStore.length)

mail/extensions/newsblog/content/subscriptions.js

@@ -53,7 +53,6 @@ function openFeedEditor(feedProperties)
     return feedProperties;
 } 
 
-
 // status helper routines
 
 function updateStatusItem(aID, aValue)
@@ -78,8 +77,6 @@ var feedDownloadCallback = {
     if (feed)
     {
       updateStatusItem('progressMeter', 100);
-      updateStatusItem('statusText', document.getElementById("bundle_newsblog").getString('subscribe-validFeedFound'));
-      updateStatusItem('statusText', 'Valid Feed Found!');
 
       var server = getIncomingServer();
       // if we get here...we should always have a folder by now...either
@@ -101,6 +98,16 @@ var feedDownloadCallback = {
     setTimeout(clearStatusInfo, 1000);
   },
 
+  // this gets called after the RSS parser finishes storing a feed item to disk
+  // aCurrentFeedItems is an integer corresponding to how many feed items have been downloaded so far
+  // aMaxFeedItems is an integer corresponding to the total number of feed items to download
+  onFeedItemStored: function (feed, aCurrentFeedItems, aMaxFeedItems)
+  { 
+    updateStatusItem('statusText', 
+      document.getElementById("bundle_newsblog").getFormattedString("subscribe-fetchingFeedItems", [aCurrentFeedItems, aMaxFeedItems]) );
+    this.onProgress(aCurrentFeedItems, aMaxFeedItems);
+  },
+
   onProgress: function(aProgress, aProgressMax)
   {
     updateStatusItem('progressMeter', (aProgress * 100) / aProgressMax);

mail/extensions/newsblog/locale/newsblog.properties

@@ -1,6 +1,10 @@
 # Status strings used in the subscribe dialog
 
-subscribe-validFeedFound=Valid Feed Found!
-subscribe-validating=Validating the feed...
+subscribe-validating=Verifying the feed...
 
+# when downloading new feed items from the subscribe dialog. 
+# LOCALIZATION NOTE: Do not translate %d in the following line.
+# The first %S will receive the number of messages received so far;
+# the second %S will receive the total number of messages
+subscribe-fetchingFeedItems=Downloading feed articles (%S of %S)