From b32369d1850f1ecc8f463e2e376dda74777bff9c Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Wed, 21 Jul 2021 17:10:05 +0800
Subject: [PATCH] App: insert UUID property to trace the source of copied
 object

A property _ObjectUUID will be added to an object before it is being to
copied, if the property does not exists. Anoter propert _SourceUUID
property will be added to any copied object, with value set to its
source objct's _ObjectUUID.
---
 src/App/Document.cpp | 22 +++++++++++++++++++++-
 src/Base/Uuid.h      |  3 +++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/App/Document.cpp b/src/App/Document.cpp
index 3db5e438c3..bfe0493b41 100644
--- a/src/App/Document.cpp
+++ b/src/App/Document.cpp
@@ -1835,8 +1835,15 @@ void Document::exportObjects(const std::vector<App::DocumentObject*>& obj, std::
 
     if(FC_LOG_INSTANCE.isEnabled(FC_LOGLEVEL_LOG)) {
         for(auto o : obj) {
-            if(o && o->getNameInDocument())
+            if(o && o->getNameInDocument()) {
                 FC_LOG("exporting " << o->getFullName());
+                if (!o->getPropertyByName("_ObjectUUID")) {
+                    auto prop = static_cast<PropertyUUID*>(o->addDynamicProperty(
+                            "App::PropertyUUID", "_ObjectUUID", nullptr, nullptr,
+                            Prop_Output | Prop_Hidden));
+                    prop->setValue(Base::Uuid::createUuid());
+                }
+            }
         }
     }
 
@@ -2195,6 +2202,19 @@ Document::importObjects(Base::XMLReader& reader)
         if(o && o->getNameInDocument()) {
             o->setStatus(App::ObjImporting,true);
             FC_LOG("importing " << o->getFullName());
+            if (auto propUUID = Base::freecad_dynamic_cast<PropertyUUID>(
+                        o->getPropertyByName("_ObjectUUID")))
+            {
+                auto propSource = Base::freecad_dynamic_cast<PropertyUUID>(
+                        o->getPropertyByName("_SourceUUID"));
+                if (!propSource)
+                    propSource = static_cast<PropertyUUID*>(o->addDynamicProperty(
+                                "App::PropertyUUID", "_SourceUUID", nullptr, nullptr,
+                                Prop_Output | Prop_Hidden));
+                if (propSource)
+                    propSource->setValue(propUUID->getValue());
+                propUUID->setValue(Base::Uuid::createUuid());
+            }
         }
     }
 
diff --git a/src/Base/Uuid.h b/src/Base/Uuid.h
index 93e7d1986e..1e68a533ce 100644
--- a/src/Base/Uuid.h
+++ b/src/Base/Uuid.h
@@ -50,6 +50,9 @@ public:
     const std::string& getValue(void) const;
     static std::string createUuid(void);
 
+    bool operator==(const Uuid &other) const {return _uuid == other._uuid;}
+    bool operator<(const Uuid &other) const {return _uuid < other._uuid;}
+
 private:
     std::string _uuid;
 };