ModelEditor: Do not query all files in the project for their mime type

Consulting the mime type database is much too expensive to do it for all
files in a project, so take a shortcut.
Example benchmark: When loading the Qt Creator super project (with all
the commercial plugins) on my Linux machine, with this patch the time
spent in ModelIndexer::scanProject() goes down from ~8 seconds to under
300 milliseconds. Note that the UI is frozen during that period.

Task-number: QTCREATORBUG-18533
Change-Id: Id75d6bbcf37b4f4e41383a089e9e0dc5262cfbae
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Jochen Becher <jochen_becher@gmx.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/plugins/modeleditor/modelindexer.h b/src/plugins/modeleditor/modelindexer.h
index da925977b6a..708ec26e9b4 100644
--- a/src/plugins/modeleditor/modelindexer.h
+++ b/src/plugins/modeleditor/modelindexer.h
@@ -34,6 +34,8 @@ class Project;
 class FolderNode;
 }
 
+namespace Utils { class MimeType; }
+
 namespace ModelEditor {
 namespace Internal {
 
@@ -72,7 +74,8 @@ private:
 
 private:
     void scanProject(ProjectExplorer::Project *project);
-    QString findFirstModel(ProjectExplorer::FolderNode *folderNode);
+    QString findFirstModel(ProjectExplorer::FolderNode *folderNode,
+                           const Utils::MimeType &mimeType);
     void forgetProject(ProjectExplorer::Project *project);
     void removeModelFile(const QString &file, ProjectExplorer::Project *project);
     void removeDiagramReferenceFile(const QString &file, ProjectExplorer::Project *project);