Clang: Improve project part updating

The project part ids are now already created very early in the database.
This removes some checks because we can assume that an id already exists.
The project part are now completely persistent, so we can read them from
the database and compare them with new generated from a new creator
session. This should help to not recreate the same PCH again and again.

Task-number: QTCREATORBUG-21151
Change-Id: Iced818ff9f7431eaed3e37978087cc0a43b9afda
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/tools/clangrefactoringbackend/source/symbolindexer.h

@@ -31,9 +31,10 @@
 #include "builddependenciesstorageinterface.h"
 #include "clangpathwatcher.h"
 
+#include <filecontainerv2.h>
 #include <precompiledheaderstorageinterface.h>
 #include <projectpartcontainer.h>
-#include <filecontainerv2.h>
+#include <projectpartsstorageinterface.h>
 
 namespace ClangBackEnd {
 
@@ -49,12 +50,13 @@ public:
                   ClangPathWatcherInterface &pathWatcher,
                   FilePathCachingInterface &filePathCache,
                   FileStatusCache &fileStatusCache,
-                  Sqlite::TransactionInterface &transactionInterface);
+                  Sqlite::TransactionInterface &transactionInterface,
+                  ProjectPartsStorageInterface &projectPartsStorage);
 
     void updateProjectParts(ProjectPartContainers &&projectParts);
     void updateProjectPart(ProjectPartContainer &&projectPart);
 
-    void pathsWithIdsChanged(const Utils::SmallStringVector &ids) override;
+    void pathsWithIdsChanged(const ProjectPartIds &ids) override;
     void pathsChanged(const FilePathIds &filePathIds) override;
     void updateChangedPath(FilePathId filePath,
                            std::vector<SymbolIndexerTask> &symbolIndexerTask);
@@ -78,6 +80,7 @@ private:
     FilePathCachingInterface &m_filePathCache;
     FileStatusCache &m_fileStatusCache;
     Sqlite::TransactionInterface &m_transactionInterface;
+    ProjectPartsStorageInterface &m_projectPartsStorage;
 };
 
 } // namespace ClangBackEnd