std::unique_ptr awt_Canvas.cpp

src/java.desktop/windows/native/libawt/windows/awt_Canvas.cpp

@@ -23,6 +23,10 @@
  * questions.
  */
 
+#include <functional>
+#include <memory>
+#include <type_traits>
+
 #include "awt_Toolkit.h"
 #include "awt_Canvas.h"
 #include "awt_Win32GraphicsConfig.h"
@@ -205,31 +209,13 @@ MsgRouting AwtCanvas::HandleEvent(MSG *msg, BOOL synthetic)
 void AwtCanvas::_SetEraseBackground(void *param) {
     JNIEnv *env = (JNIEnv *) JNU_GetEnv(jvm, JNI_VERSION_1_2);
 
-    class ResourceGuard final {
-        JNIEnv* env;
-        SetEraseBackgroundStruct* background;
-        jobject canvas;
-
-    public:
-        ResourceGuard(JNIEnv* env, SetEraseBackgroundStruct* background, jobject canvas)
-            : env(env), background(background), canvas(canvas) {
-
-        }
-        ~ResourceGuard() {
-            env->DeleteGlobalRef(canvas);
-            delete background;
-        }
-    };
-
-    SetEraseBackgroundStruct *sebs = static_cast<SetEraseBackgroundStruct *>(param);
-    jobject canvas = sebs->canvas;
+    std::unique_ptr<SetEraseBackgroundStruct> sebs(static_cast<SetEraseBackgroundStruct *>(param));
+    std::unique_ptr<std::remove_pointer<jobject>::type, std::function<void (jobject)>> canvas(sebs->canvas, [&env] (jobject canvas) -> void { env->DeleteGlobalRef(canvas); });
     jboolean doErase = sebs->doErase;
     jboolean doEraseOnResize = sebs->doEraseOnResize;
 
-    ResourceGuard guard(env, sebs, canvas);
-
     PDATA pData;
-    JNI_CHECK_PEER_RETURN(canvas);
+    JNI_CHECK_PEER_RETURN(canvas.get());
 
     AwtCanvas *c = (AwtCanvas*) pData;
     c->m_eraseBackground = doErase;