From 78f99c03b31dd7850a2eeebbf88e47e391376293 Mon Sep 17 00:00:00 2001
Message-Id: <78f99c03b31dd7850a2eeebbf88e47e391376293@dist-git>
From: Sukrit Bhatnagar <skrtbhtngr@gmail.com>
Date: Fri, 3 May 2019 13:54:30 +0200
Subject: [PATCH] util: alloc: add macros for implementing automatic cleanup
 functionality

New macros are introduced which help in adding GNU C's cleanup
attribute to variable declarations. Variables declared with these
macros will have their allocated memory freed automatically when
they go out of scope.

Signed-off-by: Sukrit Bhatnagar <skrtbhtngr@gmail.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
(cherry picked from commit dcec13f5a2ba17223d403ff9e9fed916a4dd9c04)

https: //bugzilla.redhat.com/show_bug.cgi?id=1505998
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Message-Id: <7ca85d7157eda723aac994f7c9f0f04ed9a35ab5.1556884442.git.eskultet@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
---
 src/util/viralloc.h | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/src/util/viralloc.h b/src/util/viralloc.h
index 69d0f904f1..a23aa188bb 100644
--- a/src/util/viralloc.h
+++ b/src/util/viralloc.h
@@ -596,4 +596,46 @@ void virAllocTestInit(void);
 int virAllocTestCount(void);
 void virAllocTestOOM(int n, int m);
 void virAllocTestHook(void (*func)(int, void*), void *data);
+
+# define VIR_AUTOPTR_FUNC_NAME(type) type##AutoPtrFree
+
+/**
+ * VIR_DEFINE_AUTOPTR_FUNC:
+ * @type: type of the variable to be freed automatically
+ * @func: cleanup function to be automatically called
+ *
+ * This macro defines a function for automatic freeing of
+ * resources allocated to a variable of type @type. This newly
+ * defined function works as a necessary wrapper around @func.
+ */
+# define VIR_DEFINE_AUTOPTR_FUNC(type, func) \
+    static inline void VIR_AUTOPTR_FUNC_NAME(type)(type **_ptr) \
+    { \
+        if (*_ptr) \
+            (func)(*_ptr); \
+        *_ptr = NULL; \
+    } \
+
+/**
+ * VIR_AUTOFREE:
+ * @type: type of the variable to be freed automatically
+ *
+ * Macro to automatically free the memory allocated to
+ * the variable declared with it by calling virFree
+ * when the variable goes out of scope.
+ */
+# define VIR_AUTOFREE(type) __attribute__((cleanup(virFree))) type
+
+/**
+ * VIR_AUTOPTR:
+ * @type: type of the variable to be freed automatically
+ *
+ * Macro to automatically free the memory allocated to
+ * the variable declared with it by calling the function
+ * defined by VIR_DEFINE_AUTOPTR_FUNC when the variable
+ * goes out of scope.
+ */
+# define VIR_AUTOPTR(type) \
+    __attribute__((cleanup(VIR_AUTOPTR_FUNC_NAME(type)))) type *
+
 #endif /* __VIR_MEMORY_H_ */
-- 
2.21.0