qmljs: delay import scan until at least one qml file is parsed

Task-number: QTCREATORBUG-10899
Change-Id: I5dca739a89434c7b5813c7a79a76ab7c22e3d71d
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qmljstools/qmljsmodelmanager.cpp

@@ -232,6 +232,7 @@ QStringList QmlJSTools::qmlAndJsGlobPatterns()
 
 ModelManager::ModelManager(QObject *parent):
         ModelManagerInterface(parent),
+        m_shouldScanImports(false),
         m_pluginDumper(new PluginDumper(this))
 {
     m_synchronizer.setCancelOnWait(true);
@@ -380,6 +381,20 @@ QFuture<void> ModelManager::refreshSourceFiles(const QStringList &sourceFiles,
     if (sourceFiles.count() > 1)
         ProgressManager::addTask(result, tr("Indexing"), Constants::TASK_INDEX);
 
+    if (sourceFiles.count() > 1 && !m_shouldScanImports) {
+        bool scan = false;
+        {
+            QMutexLocker l(&m_mutex);
+            if (!m_shouldScanImports) {
+                m_shouldScanImports = true;
+                scan = true;
+            }
+        }
+        if (scan)
+        updateImportPaths();
+    }
+
+
     return result;
 }
 
@@ -1113,6 +1128,8 @@ void ModelManager::updateImportPaths()
 
     updateSourceFiles(importedFiles, true);
 
+    if (!m_shouldScanImports)
+        return;
     QStringList pathToScan;
     {
         QMutexLocker l(&m_mutex);

src/plugins/qmljstools/qmljsmodelmanager.h

@@ -179,6 +179,7 @@ private:
     QmlJS::QmlLanguageBundles m_activeBundles;
     QmlJS::QmlLanguageBundles m_extendedBundles;
     QmlJS::ViewerContext m_vContext;
+    bool m_shouldScanImports;
     QSet<QString> m_scannedPaths;
 
     QTimer *m_updateCppQmlTypesTimer;