librbd: make librbd::Image moveable

Adds move constructor and move assignment operator to the librbd::Image.
Also marks copy ctor/assign op as deleted, and makes them public for better compiler diagnostics.

Signed-off-by: Anatoly Scheglov <finch@mts.ru>

Author: Anatoly Scheglov

src/include/rbd/librbd.hpp

@@ -532,6 +532,14 @@ class CEPH_RBD_API Image
   Image();
   ~Image();
 
+  // non-copyable
+  Image(const Image& rhs) = delete;
+  Image& operator=(const Image& rhs) = delete;
+
+  // moveable
+  Image(Image&& rhs) noexcept;
+  Image& operator=(Image&& rhs) noexcept;
+
   int close();
   int aio_close(RBD::AioCompletion *c);
 
@@ -854,9 +862,6 @@ class CEPH_RBD_API Image
 private:
   friend class RBD;
 
-  Image(const Image& rhs);
-  const Image& operator=(const Image& rhs);
-
   image_ctx_t ctx;
 };
 

src/librbd/librbd.cc

@@ -51,6 +51,7 @@
 #include "librbd/io/ReadResult.h"
 #include <algorithm>
 #include <string>
+#include <utility>
 #include <vector>
 
 #ifdef WITH_LTTNG
@@ -1609,6 +1610,17 @@ namespace librbd {
     close();
   }
 
+  Image::Image(Image&& rhs) noexcept : ctx{std::exchange(rhs.ctx, nullptr)}
+  {
+  }
+
+  Image& Image::operator=(Image&& rhs) noexcept
+  {
+    Image tmp(std::move(rhs));
+    std::swap(ctx, tmp.ctx);
+    return *this;
+  }
+
   int Image::close()
   {
     int r = 0;