CppTools: Turn some classes into pure value types

ProjectInfo, ProjectPart and ProjectUpdateInfo used to carry pointers
to Project and/or Toolchain, even though they were used in contexts
where these pointers were either unsafe to access or not guaranteed to
be valid anymore, which made their use difficult and error-prone.
We turn these classes into pure value types by copying in all relevant
information before the first async operation takes place.

Fixes: QTCREATORBUG-25678
Change-Id: I1914b0dbda6c7dfba6c95e5e92f2d69977755590
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/cpptools/cpptoolsreuse.cpp

@@ -29,11 +29,13 @@
 #include "cpprefactoringchanges.h"
 #include "cpptoolsconstants.h"
 #include "cpptoolsplugin.h"
+#include "projectinfo.h"
 
 #include <coreplugin/documentmanager.h>
 #include <coreplugin/editormanager/editormanager.h>
 #include <coreplugin/idocument.h>
 #include <coreplugin/messagemanager.h>
+#include <projectexplorer/session.h>
 
 #include <cplusplus/Overview.h>
 #include <cplusplus/LookupContext.h>
@@ -572,4 +574,14 @@ NamespaceAST *NSCheckerVisitor::currentNamespace()
     return m_enteredNamespaces.empty() ? nullptr : m_enteredNamespaces.back();
 }
 
+ProjectExplorer::Project *projectForProjectPart(const ProjectPart &part)
+{
+    return ProjectExplorer::SessionManager::projectWithProjectFilePath(part.topLevelProject);
+}
+
+ProjectExplorer::Project *projectForProjectInfo(const ProjectInfo &info)
+{
+    return ProjectExplorer::SessionManager::projectWithProjectFilePath(info.projectFilePath());
+}
+
 } // CppTools