record the parent ID of each change operation

src/core/Buffer.cc

@@ -40,7 +40,7 @@ void Buffer::common_initialization()
     }
     m_change_buffer = std::make_shared<GapBuffer>();
     m_operation_level = 0;
-    m_current_operation_index = 0u;
+    m_current_change_operation_index = 0xFFFFFFFFu;
 }
 
 void Buffer::load_empty_buffer()
@@ -240,6 +240,7 @@ void Buffer::record_change(uint8_t data[], size_t length, size_t buffer_position
     if (!m_current_change_operation)
     {
         m_current_change_operation = std::make_shared<ChangeOperation>();
+        m_current_change_operation->parent = m_current_change_operation_index;
     }
     if (m_current_change_operation->changes.size() > 0)
     {
@@ -309,12 +310,12 @@ void Buffer::save_current_operation()
     if (m_current_change_operation)
     {
         size_t new_change_operation_index = m_change_operations.size();
-        if (m_current_operation_index < new_change_operation_index)
+        if (m_current_change_operation_index < new_change_operation_index)
         {
-            m_change_operations[m_current_operation_index]->children.push_back(new_change_operation_index);
+            m_change_operations[m_current_change_operation_index]->children.push_back(new_change_operation_index);
         }
         m_change_operations.push_back(m_current_change_operation);
         m_current_change_operation = nullptr;
-        m_current_operation_index = new_change_operation_index;
+        m_current_change_operation_index = new_change_operation_index;
     }
 }

src/core/Buffer.h

@@ -141,7 +141,7 @@ protected:
     std::string m_filename;
     std::shared_ptr<ChangeOperation> m_current_change_operation;
     int m_operation_level;
-    size_t m_current_operation_index;
+    size_t m_current_change_operation_index;
     std::vector<std::shared_ptr<ChangeOperation>> m_change_operations;
 
     void common_initialization();

src/core/ChangeOperation.h

@@ -8,6 +8,7 @@
 class ChangeOperation
 {
 public:
+    size_t parent;
     std::list<ChangeUnit> changes;
     std::list<size_t> children;
 };