1 files changed, 101 insertions, 0 deletions
diff --git a/libglusterfs/src/glusterfs/refcount.h b/libglusterfs/src/glusterfs/refcount.h
new file mode 100644
index 00000000000..cf922dabb05
--- /dev/null
+++ b/libglusterfs/src/glusterfs/refcount.h
@@ -0,0 +1,101 @@
+/*
+  Copyright (c) 2015 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+*/
+
+#ifndef _REFCOUNT_H
+#define _REFCOUNT_H
+
+/* check for compiler support for __sync_*_and_fetch()
+ *
+ * a more comprehensive feature test is shown at
+ * http://lists.iptel.org/pipermail/semsdev/2010-October/005075.html
+ * this is sufficient for RHEL5 i386 builds
+ */
+#if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) &&                \
+    !defined(__i386__)
+#undef REFCOUNT_NEEDS_LOCK
+#else
+#define REFCOUNT_NEEDS_LOCK
+#include "glusterfs/locking.h"
+#endif /* compiler support for __sync_*_and_fetch() */
+
+typedef void (*gf_ref_release_t)(void *data);
+
+struct _gf_ref {
+#ifdef REFCOUNT_NEEDS_LOCK
+    gf_lock_t lk; /* lock for atomically adjust cnt */
+#endif
+    unsigned int cnt; /* number of users, free on 0 */
+
+    gf_ref_release_t release; /* cleanup when cnt == 0 */
+    void *data;               /* parameter passed to release() */
+};
+typedef struct _gf_ref gf_ref_t;
+
+/* _gf_ref_get -- increase the refcount
+ *
+ * @return: greater then 0 when a reference was taken, 0 when not
+ */
+void *
+_gf_ref_get(gf_ref_t *ref);
+
+/* _gf_ref_put -- decrease the refcount
+ *
+ * @return: greater then 0 when there are still references, 0 when cleanup
+ *          should be done, gf_ref_release_t is called on cleanup
+ */
+unsigned int
+_gf_ref_put(gf_ref_t *ref);
+
+/* _gf_ref_init -- initialize an embedded refcount object
+ *
+ * @release: function to call when the refcount == 0
+ * @data: parameter to be passed to @release
+ */
+void
+_gf_ref_init(gf_ref_t *ref, gf_ref_release_t release, void *data);
+
+/*
+ * Strong suggestion to use the simplified GF_REF_* API.
+ */
+
+/* GF_REF_DECL -- declaration to put inside your structure
+ *
+ * Example:
+ *   struct my_struct {
+ *       GF_REF_DECL;
+ *
+ *       ... // additional members
+ *   };
+ */
+#define GF_REF_DECL gf_ref_t _ref
+
+/* GF_REF_INIT -- initialize a GF_REF_DECL structure
+ *
+ * @p: allocated structure with GF_REF_DECL
+ * @d: destructor to call once refcounting reaches 0
+ *
+ * Sets the refcount to 1.
+ */
+#define GF_REF_INIT(p, d) _gf_ref_init(&(p)->_ref, (gf_ref_release_t)d, p)
+
+/* GF_REF_GET -- increase the refcount of a GF_REF_DECL structure
+ *
+ * @return: greater then 0 when a reference was taken, 0 when not
+ */
+#define GF_REF_GET(p) _gf_ref_get(&(p)->_ref)
+
+/* GF_REF_PUT -- decrease the refcount of a GF_REF_DECL structure
+ *
+ * @return: greater then 0 when there are still references, 0 when cleanup
+ *          should be done, gf_ref_release_t is called on cleanup
+ */
+#define GF_REF_PUT(p) _gf_ref_put(&(p)->_ref)
+
+#endif /* _REFCOUNT_H */