C++: cache results of linksForIdentifier in HelpItem.

The method linksForIdentifier was called at least thrice when generating
a single valid tooltip in the C++ editor. Now the cached, and the cache
can be "initialised" during construction. This reduces the time spent
for creating a tooltip by 30%.

Task-number: QTCREATORBUG-8970
Change-Id: I5130b769e977c6ffced1a87715831386ef0d5319
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/src/plugins/cppeditor/cpphoverhandler.cpp b/src/plugins/cppeditor/cpphoverhandler.cpp
index 086595b957..cf7d3bab47 100644
--- a/src/plugins/cppeditor/cpphoverhandler.cpp
+++ b/src/plugins/cppeditor/cpphoverhandler.cpp
@@ -77,11 +77,19 @@ void CppHoverHandler::identifyMatch(TextEditor::ITextEditor *editor, int pos)
             const QSharedPointer<CppElement> &cppElement = evaluator.cppElement();
             if (!isDiagnosticTooltip())
                 setToolTip(cppElement->tooltip);
-            foreach (const QString &helpId, cppElement->helpIdCandidates) {
-                if (!Core::HelpManager::instance()->linksForIdentifier(helpId).isEmpty()) {
+            QStringList candidates = cppElement->helpIdCandidates;
+            candidates.removeDuplicates();
+            HelpManager *hm = HelpManager::instance();
+            foreach (const QString &helpId, candidates) {
+                if (helpId.isEmpty())
+                    continue;
+
+                const QMap<QString, QUrl> helpLinks = hm->linksForIdentifier(helpId);
+                if (!helpLinks.isEmpty()) {
                     setLastHelpItemIdentified(TextEditor::HelpItem(helpId,
                                                                    cppElement->helpMark,
-                                                                   cppElement->helpCategory));
+                                                                   cppElement->helpCategory,
+                                                                   helpLinks));
                     break;
                 }
             }