cache: provide safe variant of nl_cache_mngt_require() and use it

This makes runtime removal of cache operations possible if non-safe
API is not in use by application. The non-safe API will be removed
in the next major version.

Signed-off-by: Thomas Graf <tgraf@suug.ch>

1 files changed, 26 insertions, 6 deletions

diff --git a/lib/cache_mngt.c b/lib/cache_mngt.c
index 914ab9b..fbb702f 100644
--- a/lib/cache_mngt.c
+++ b/lib/cache_mngt.c
@@ -390,14 +390,15 @@ struct nl_cache *__nl_cache_mngt_require(const char *name)
 }
 
 /**
- * Demand the use of a global cache
- * @arg name		name of the required object type
+ * Return cache previously provided via nl_cache_mngt_provide()
+ * @arg name		Name of cache to lookup
  *
- * Trys to find a cache of the specified type for global
- * use.
+ * @attention This function is not safe, it does not increment the reference
+ *            counter. Please use nl_cache_mngt_require_safe().
+ *
+ * @see nl_cache_mngt_require_safe()
  *
- * @return A cache provided by another subsystem of the
- *         specified type marked to be available.
+ * @return Pointer to cache or NULL if none registered
  */
 struct nl_cache *nl_cache_mngt_require(const char *name)
 {
@@ -412,6 +413,25 @@ struct nl_cache *nl_cache_mngt_require(const char *name)
 	return cache;
 }
 
+/**
+ * Return cache previously provided via nl_cache_mngt_provide()
+ * @arg name		Name of cache to lookup
+ *
+ * @note The reference counter of the returned cache is incremented
+ *       and must be decremented after use with nl_cache_put().
+ *
+ * @return Pointer to cache or NULL if none registered
+ */
+struct nl_cache *nl_cache_mngt_require_safe(const char *name)
+{
+	struct nl_cache *cache;
+
+	if ((cache = nl_cache_mngt_require(name)))
+		nl_cache_get(cache);
+	
+	return cache;
+}
+
 /** @} */
 
 /** @} */