Move change listener registration to BufferChangeListener_AutoRegister

DynamicSelectionList now just inherit from this class, so that
the registration logic can be shared.

1 files changed, 52 insertions, 0 deletions

diff --git a/src/buffer.hh b/src/buffer.hh
index f3c80afc..260c00a0 100644
--- a/src/buffer.hh
+++ b/src/buffer.hh
@@ -244,6 +244,58 @@ constexpr Buffer::Flags operator~(Buffer::Flags lhs)
     return (Buffer::Flags)(~(int)lhs);
 }
 
+class BufferChangeListener_AutoRegister : public BufferChangeListener
+{
+public:
+    BufferChangeListener_AutoRegister(const Buffer& buffer)
+        : m_buffer(&buffer)
+    {
+        m_buffer->change_listeners().insert(this);
+    }
+
+    BufferChangeListener_AutoRegister(const BufferChangeListener_AutoRegister& other)
+        : m_buffer(other.m_buffer)
+    {
+        m_buffer->change_listeners().insert(this);
+    }
+
+    BufferChangeListener_AutoRegister(BufferChangeListener_AutoRegister&& other)
+        : m_buffer(other.m_buffer)
+    {
+        m_buffer->change_listeners().insert(this);
+    }
+
+    ~BufferChangeListener_AutoRegister()
+    {
+        m_buffer->change_listeners().erase(this);
+    }
+
+    BufferChangeListener_AutoRegister& operator=(const BufferChangeListener_AutoRegister& other)
+    {
+        if (m_buffer != other.m_buffer)
+        {
+            m_buffer->change_listeners().erase(this);
+            m_buffer = other.m_buffer;
+            m_buffer->change_listeners().insert(this);
+        }
+        return *this;
+    }
+
+    BufferChangeListener_AutoRegister& operator=(BufferChangeListener_AutoRegister&& other)
+    {
+        if (m_buffer != other.m_buffer)
+        {
+            m_buffer->change_listeners().erase(this);
+            m_buffer = other.m_buffer;
+            m_buffer->change_listeners().insert(this);
+        }
+        return *this;
+    }
+
+    const Buffer& buffer() const { return *m_buffer; }
+private:
+    const Buffer* m_buffer;
+};
 
 }