Refactor buffer undo tree

Store the undo tree as an array of undo nodes, instead of as a
pointer based tree.

1 files changed, 18 insertions, 18 deletions

diff --git a/src/buffer.hh b/src/buffer.hh
index 7ff5bab7..6b98e7c8 100644
--- a/src/buffer.hh
+++ b/src/buffer.hh
@@ -119,6 +119,8 @@ public:
     };
     friend constexpr bool with_bit_ops(Meta::Type<Flags>) { return true; }
 
+    enum class HistoryId : size_t { First = 0, Invalid = (size_t)-1 };
+
     Buffer(String name, Flags flags, StringView data = {},
            timespec fs_timestamp = InvalidTime);
     Buffer(const Buffer&) = delete;
@@ -142,9 +144,9 @@ public:
     void           commit_undo_group();
     bool           undo(size_t count = 1);
     bool           redo(size_t count = 1);
-    bool           move_to(size_t history_id);
-    size_t         current_history_id() const noexcept;
-    size_t         next_history_id() const noexcept { return m_next_history_id; }
+    bool           move_to(HistoryId id);
+    HistoryId      current_history_id() const noexcept { return m_history_id; }
+    HistoryId      next_history_id() const noexcept { return (HistoryId)m_history.size(); }
 
     String         string(BufferCoord begin, BufferCoord end) const;
     StringView     substr(BufferCoord begin, BufferCoord end) const;
@@ -256,27 +258,25 @@ private:
 
     using UndoGroup = Vector<Modification, MemoryDomain::BufferMeta>;
 
-   struct HistoryNode : SafeCountable, UseMemoryDomain<MemoryDomain::BufferMeta>
+    struct HistoryNode : UseMemoryDomain<MemoryDomain::BufferMeta>
     {
-        HistoryNode(size_t id, HistoryNode* parent);
+        HistoryNode(HistoryId parent);
 
-        UndoGroup undo_group;
-        Vector<std::unique_ptr<HistoryNode>, MemoryDomain::BufferMeta> childs;
-        SafePtr<HistoryNode> parent;
-        HistoryNode* redo_child = nullptr; // not a SafePtr to avoid lifetime issues between this and childs
-        size_t id;
+        HistoryId parent;
+        HistoryId redo_child = HistoryId::Invalid;
         TimePoint timepoint;
+        UndoGroup undo_group;
     };
 
-    size_t                m_next_history_id = 0;
-    HistoryNode           m_history;
-    SafePtr<HistoryNode>  m_history_cursor;
-    SafePtr<HistoryNode>  m_last_save_history_cursor;
-    UndoGroup             m_current_undo_group;
-
-    void move_to(HistoryNode* history_node);
+    Vector<HistoryNode> m_history;
+    HistoryId           m_history_id = HistoryId::Invalid;
+    HistoryId           m_last_save_history_id = HistoryId::Invalid;
+    UndoGroup           m_current_undo_group;
 
-    template<typename Func> HistoryNode* find_history_node(HistoryNode* node, const Func& func);
+          HistoryNode& history_node(HistoryId id)       { return m_history[(size_t)id]; }
+    const HistoryNode& history_node(HistoryId id) const { return m_history[(size_t)id]; }
+          HistoryNode& current_history_node()           { return m_history[(size_t)m_history_id]; }
+    const HistoryNode& current_history_node()     const { return m_history[(size_t)m_history_id]; }
 
     Vector<Change, MemoryDomain::BufferMeta> m_changes;