[gnome-shell] search: Only do a subsearch if the previous results have returned from DBus

[Jasper St. Pierre <jstpierre src gnome org>]

commit 842c7928687fe6d08d11856efd60c271fc096dad
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Mon Nov 4 14:47:13 2013 -0500

    search: Only do a subsearch if the previous results have returned from DBus
    
    There's a potential race condition in the search code: if we have an
    outstanding search call to a provider for search "A", and if before it comes
    back we do a subsearch for "AB", we won't have any results to pass along.
    
    Previously, we used an empty list when storing the provider results, so we
    effectively told the remote search app to filter through this empty list for
    any search results that meet the new query, meaning we showed the user 0
    results for the provider in this case.
    
    Now that we don't store an empty list, but instead store `undefined`, this race
    raises a warning. Solve it by doing an initial search query in this case
    instead.
    
    The search code isn't too smart about chained subsearches: now, if we hit this
    race while already on a subsearch, we'll do an initial search for the subsearch
    query instead, but that is much better than showing the user nothing. This
    could be fixed in the future for a performance improvement.
    
    Reviewed-by: Florian Müllner <fmuellner gnome org>

 js/ui/search.js |   13 +++++--------
 1 files changed, 5 insertions(+), 8 deletions(-)
---
diff --git a/js/ui/search.js b/js/ui/search.js
index 4bde7fc..50868e3 100644
--- a/js/ui/search.js
+++ b/js/ui/search.js
@@ -110,16 +110,13 @@ const SearchSystem = new Lang.Class({
 
         this._terms = terms;
 
-        if (isSubSearch) {
-            this._providers.forEach(Lang.bind(this, function(provider) {
-                let previousProviderResults = previousResults[provider.id];
+        this._providers.forEach(Lang.bind(this, function(provider) {
+            let previousProviderResults = previousResults[provider.id];
+            if (isSubSearch && previousProviderResults)
                 provider.getSubsearchResultSet(previousProviderResults, terms, Lang.bind(this, 
this._gotResults, provider), this._cancellable);
-            }));
-        } else {
-            this._providers.forEach(Lang.bind(this, function(provider) {
+            else
                 provider.getInitialResultSet(terms, Lang.bind(this, this._gotResults, provider), 
this._cancellable);
-            }));
-        }
+        }));
     }
 });
 Signals.addSignalMethods(SearchSystem.prototype);