implement blocks data conversion

src/content/ContentReport.cpp

@@ -56,11 +56,40 @@ std::shared_ptr<ContentReport> ContentReport::create(
         indices, blocks_c, items_c, regionsVersion);
     report->blocks.setup(blocklist, content->blocks);
     report->items.setup(itemlist, content->items);
+
+    for (const auto& [name, map] : root["blocks-data"].asObject()) {
+        data::StructLayout layout;
+        layout.deserialize(map);
+        auto def = content->blocks.find(name);
+        if (def == nullptr) {
+            continue;
+        }
+        if (def->dataStruct == nullptr) {
+            ContentIssue issue {ContentIssueType::BLOCK_DATA_LAYOUTS_UPDATE};
+            report->issues.push_back(issue);
+            report->dataLoss.push_back(name+": discard data");
+            continue;
+        }
+        auto incapatibility = layout.checkCompatibility(*def->dataStruct);
+        if (!incapatibility.empty()) {
+            ContentIssue issue {ContentIssueType::BLOCK_DATA_LAYOUTS_UPDATE};
+            report->issues.push_back(issue);
+            for (const auto& error : incapatibility) {
+                report->dataLoss.push_back(
+                    "[" + name + "] field " + error.name + " - " +
+                    data::to_string(error.type)
+                );
+            }
+        }
+        report->blocksDataLayouts[name] = std::move(layout);
+    }
+
     report->buildIssues();
 
     if (report->isUpgradeRequired() || 
         report->hasContentReorder() || 
-        report->hasMissingContent()) {
+        report->hasMissingContent() ||
+        report->hasDataLoss()) {
         return report;
     } else {
         return nullptr;