lib/cache: exported cache storage

diff --git a/lib/cache.c b/lib/cache.c
index f8ff599826c27a1c50019c5cdca1ae36753c5c3e..2a48f7b49c1c5f8973a4a89318f7b6451b8861e8 100644 (file)
--- a/lib/cache.c
+++ b/lib/cache.c
@@ -28,7 +28,9 @@
 #include "lib/cache.h"
 #include "lib/defines.h"
 
-#define db_api namedb_lmdb_api()
+/** Used cache storage engine (default LMDB) */
+const namedb_api_t *(*kr_cache_storage)(void) = namedb_lmdb_api;
+#define db_api kr_cache_storage()
 
 namedb_t *kr_cache_open(const char *handle, mm_ctx_t *mm, size_t maxsize)
 {
@@ -232,22 +234,3 @@ int kr_cache_clear(namedb_txn_t *txn)
 
        return db_api->clear(txn);
 }
-
-int kr_cache_prune(namedb_txn_t *txn, uint32_t timestamp)
-{
-       /* Whole cache sweep is not feasible as we don't have a list of items sorted
-        * by age nor any sort of LRU/MRU, completely random replace is not possible
-        * as well.
-        * - The LMDB also can't delete items when the MAPSIZE is reached.
-        * - So we're probably need to iteratively scan the LMDB and prune aged
-        *   items.
-        * - This is not ideal, because queries won't be able to write to cache
-        *   until at least some entry ages out.
-        * - Idea - make poor man's LRU with two databases doing following:
-        *   - Fill up 1, mark that it's unwritable
-        *   - Fill up 2, mark that it's unwritable
-        *   - Clear 1, all writes will now go in there
-        *   - This gives us LR(written) with resolution 2
-        */
-       return KNOT_EOK;
-}

diff --git a/lib/cache.h b/lib/cache.h
index 850d88676a867340e076ce37c2e94df0485c7f9d..23c864b94fc2d0a1e9b5f421bc845b8450f38aa9 100644 (file)
--- a/lib/cache.h
+++ b/lib/cache.h
@@ -32,6 +32,9 @@ struct kr_cache_rrset
        uint8_t  data[];
 };
 
+/** Used storage API for cache (default LMDB) */
+extern const namedb_api_t *(*kr_cache_storage)(void);
+
 /**
  * Open/create persistent cache in given path.
  * @param handle Path to existing directory where the DB should be created.
@@ -115,12 +118,4 @@ int kr_cache_remove(namedb_txn_t *txn, const knot_rrset_t *rr);
  */
 int kr_cache_clear(namedb_txn_t *txn);
 
-/**
- * Clear aged items from the database.
- * @param txn transaction instance
- * @param timestamp current time
- * @return KNOT_E*
- */
-int kr_cache_prune(namedb_txn_t *txn, uint32_t timestamp);
-
 /** @} */