Replace std::shared_ptr with homemade, intrusive, ref_ptr

That saves a lot of memory as sizeof(SharedString) is now one
pointer less.

1 files changed, 65 insertions, 0 deletions

diff --git a/src/ref_ptr.hh b/src/ref_ptr.hh
new file mode 100644
index 00000000..7bd2ed83
--- /dev/null
+++ b/src/ref_ptr.hh
@@ -0,0 +1,65 @@
+#ifndef ref_ptr_hh_INCLUDED
+#define ref_ptr_hh_INCLUDED
+
+namespace Kakoune
+{
+
+template<typename T>
+struct ref_ptr
+{
+    ref_ptr() = default;
+    ref_ptr(T* ptr) : m_ptr(ptr) { acquire(); }
+    ~ref_ptr() { release(); }
+    ref_ptr(const ref_ptr& other) : m_ptr(other.m_ptr) { acquire(); }
+    ref_ptr(ref_ptr&& other) : m_ptr(other.m_ptr) { other.m_ptr = nullptr; }
+
+    ref_ptr& operator=(const ref_ptr& other)
+    {
+        release();
+        m_ptr = other.m_ptr;
+        acquire();
+        return *this;
+    }
+    ref_ptr& operator=(ref_ptr&& other)
+    {
+        release();
+        m_ptr = other.m_ptr;
+        other.m_ptr = nullptr;
+        return *this;
+    }
+
+    T* operator->() const { return m_ptr; }
+    T& operator*() const { return *m_ptr; }
+
+    T* get() const { return m_ptr; }
+
+    explicit operator bool() { return m_ptr; }
+
+    friend bool operator==(const ref_ptr& lhs, const ref_ptr& rhs)
+    {
+        return lhs.m_ptr == rhs.m_ptr;
+    }
+    friend bool operator!=(const ref_ptr& lhs, const ref_ptr& rhs)
+    {
+        return lhs.m_ptr != rhs.m_ptr;
+    }
+private:
+    T* m_ptr = nullptr;
+
+    void acquire()
+    {
+        if (m_ptr)
+            inc_ref_count(m_ptr);
+    }
+
+    void release()
+    {
+        if (m_ptr)
+            dec_ref_count(m_ptr);
+        m_ptr = nullptr;
+    } 
+};
+
+}
+
+#endif // ref_ptr_hh_INCLUDED