Support Database Custom Data Merging (#3002)

* Introduce _LAST_MODIFIED custom data entry that stores the last modified datetime of the database's custom data entries
* Merge custom data from source database to target
* Modify tests to be aware of _LAST_MODIFIED entry

src/core/CustomData.cpp

@@ -16,9 +16,12 @@
  */
 
 #include "CustomData.h"
+#include "Clock.h"
 
 #include "core/Global.h"
 
+const QString CustomData::LastModified = "_LAST_MODIFIED";
+
 CustomData::CustomData(QObject* parent)
     : QObject(parent)
 {
@@ -60,6 +63,7 @@ void CustomData::set(const QString& key, const QString& value)
 
     if (addAttribute || changeValue) {
         m_data.insert(key, value);
+        updateLastModified();
         emit customDataModified();
     }
 
@@ -74,6 +78,7 @@ void CustomData::remove(const QString& key)
 
     m_data.remove(key);
 
+    updateLastModified();
     emit removed(key);
     emit customDataModified();
 }
@@ -94,6 +99,7 @@ void CustomData::rename(const QString& oldKey, const QString& newKey)
     m_data.remove(oldKey);
     m_data.insert(newKey, data);
 
+    updateLastModified();
     emit customDataModified();
     emit renamed(oldKey, newKey);
 }
@@ -108,9 +114,19 @@ void CustomData::copyDataFrom(const CustomData* other)
 
     m_data = other->m_data;
 
+    updateLastModified();
     emit reset();
     emit customDataModified();
 }
+
+QDateTime CustomData::getLastModified() const
+{
+    if (m_data.contains(LastModified)) {
+        return Clock::parse(m_data.value(LastModified));
+    }
+    return {};
+}
+
 bool CustomData::operator==(const CustomData& other) const
 {
     return (m_data == other.m_data);
@@ -152,3 +168,13 @@ int CustomData::dataSize() const
     }
     return size;
 }
+
+void CustomData::updateLastModified()
+{
+    if (m_data.size() == 1 && m_data.contains(LastModified)) {
+        m_data.remove(LastModified);
+        return;
+    }
+
+    m_data.insert(LastModified, Clock::currentDateTimeUtc().toString());
+}

src/core/CustomData.h

@@ -42,9 +42,12 @@ public:
     int size() const;
     int dataSize() const;
     void copyDataFrom(const CustomData* other);
+    QDateTime getLastModified() const;
     bool operator==(const CustomData& other) const;
     bool operator!=(const CustomData& other) const;
 
+    static const QString LastModified;
+
 signals:
     void customDataModified();
     void aboutToBeAdded(const QString& key);
@@ -55,6 +58,10 @@ signals:
     void renamed(const QString& oldKey, const QString& newKey);
     void aboutToBeReset();
     void reset();
+    void lastModified();
+
+private slots:
+    void updateLastModified();
 
 private:
     QHash<QString, QString> m_data;

src/core/Merger.cpp

@@ -609,9 +609,6 @@ Merger::ChangeList Merger::mergeMetadata(const MergeContext& context)
     // TODO HNH: missing handling of recycle bin, names, templates for groups and entries,
     //           public data (entries of newer dict override keys of older dict - ignoring
     //           their own age - it is enough if one entry of the whole dict is newer) => possible lost update
-    // TODO HNH: CustomData is merged with entries of the new customData overwrite entries
-    //           of the older CustomData - the dict with the newest entry is considered
-    //           newer regardless of the age of the other entries => possible lost update
     ChangeList changes;
     auto* sourceMetadata = context.m_sourceDb->metadata();
     auto* targetMetadata = context.m_targetDb->metadata();
@@ -624,5 +621,32 @@ Merger::ChangeList Merger::mergeMetadata(const MergeContext& context)
             changes << tr("Adding missing icon %1").arg(QString::fromLatin1(customIconId.toRfc4122().toHex()));
         }
     }
+
+    // Merge Custom Data if source is newer
+    const auto targetCustomDataModificationTime = sourceMetadata->customData()->getLastModified();
+    const auto sourceCustomDataModificationTime = targetMetadata->customData()->getLastModified();
+    if (!targetMetadata->customData()->contains(CustomData::LastModified) ||
+        (targetCustomDataModificationTime.isValid() && sourceCustomDataModificationTime.isValid() && 
+         targetCustomDataModificationTime > sourceCustomDataModificationTime)) {
+        const auto sourceCustomDataKeys = sourceMetadata->customData()->keys();
+        const auto targetCustomDataKeys = targetMetadata->customData()->keys();
+
+        // Check missing keys from source. Remove those from target
+        for (const auto& key : targetCustomDataKeys) {
+            if (!sourceMetadata->customData()->contains(key)) {
+                auto value = targetMetadata->customData()->value(key);
+                targetMetadata->customData()->remove(key);
+                changes << tr("Removed custom data %1 [%2]").arg(key, value);
+            }
+        }
+
+        // Transfer new/existing keys
+        for (const auto& key : sourceCustomDataKeys) {
+            auto value = sourceMetadata->customData()->value(key);
+            targetMetadata->customData()->set(key, value);
+            changes << tr("Adding custom data %1 [%2]").arg(key, value);
+        }
+    }
+
     return changes;
 }