Move the BookmarkFilter's matching into the main thread

We can't operate directly on the BookmarkManager and Bookmark instances
in the other thread, as they may be freely modified in the gui
thread in the same time. Since it's uncommon to have
hundreds of bookmarks set, we prepare all the needed data in the
main thread instead, which shouldn't slow down the locator
significantly.

Change-Id: I9df0a8425694632c40138fbe3667499f7fc03432
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/bookmarks/bookmarkfilter.cpp

@@ -43,12 +43,11 @@ BookmarkFilter::BookmarkFilter(BookmarkManager *manager)
     setShortcutString("b");
 }
 
-QList<LocatorFilterEntry> BookmarkFilter::matchesFor(QFutureInterface<LocatorFilterEntry> &future,
-                                                     const QString &entry)
+void BookmarkFilter::prepareSearch(const QString &entry)
 {
-    Q_UNUSED(future)
+    m_results = {};
     if (m_manager->rowCount() == 0)
-        return QList<LocatorFilterEntry>();
+        return;
 
     auto match = [this](const QString &name, BookmarkManager::Roles role) {
         return m_manager->match(m_manager->index(0, 0), role, name, -1,
@@ -74,7 +73,6 @@ QList<LocatorFilterEntry> BookmarkFilter::matchesFor(QFutureInterface<LocatorFil
                                                    + match(entry, BookmarkManager::Note)
                                                    + match(entry, BookmarkManager::LineText));
 
-    QList<LocatorFilterEntry> entries;
     for (const QModelIndex &idx : matches) {
         const Bookmark *bookmark = m_manager->bookmarkForIndex(idx);
         const QString filename = bookmark->fileName().fileName();
@@ -112,9 +110,16 @@ QList<LocatorFilterEntry> BookmarkFilter::matchesFor(QFutureInterface<LocatorFil
         }
 
         filterEntry.displayIcon = bookmark->icon();
-        entries.append(filterEntry);
+        m_results.append(filterEntry);
     }
-    return entries;
+}
+
+QList<LocatorFilterEntry> BookmarkFilter::matchesFor(QFutureInterface<LocatorFilterEntry> &future,
+                                                     const QString &entry)
+{
+    Q_UNUSED(future)
+    Q_UNUSED(entry)
+    return m_results;
 }
 
 void BookmarkFilter::accept(LocatorFilterEntry selection, QString *newText,

src/plugins/bookmarks/bookmarkfilter.h

@@ -37,6 +37,7 @@ class BookmarkFilter : public Core::ILocatorFilter
     Q_OBJECT
 public:
     explicit BookmarkFilter(BookmarkManager *manager);
+    void prepareSearch(const QString &entry) override;
     QList<Core::LocatorFilterEntry> matchesFor(QFutureInterface<Core::LocatorFilterEntry> &future,
                                                const QString &entry) override;
     void accept(Core::LocatorFilterEntry selection, QString *newText,
@@ -45,6 +46,7 @@ public:
 
 private:
     BookmarkManager *m_manager = nullptr; // not owned
+    QList<Core::LocatorFilterEntry> m_results;
 };
 
 } // namespace Internal