1 files changed, 41 insertions, 0 deletions
diff --git a/utils/cache_gc/kr_cache_gc.h b/utils/cache_gc/kr_cache_gc.h
new file mode 100644
index 0000000..c64e99e
--- /dev/null
+++ b/utils/cache_gc/kr_cache_gc.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+typedef struct {
+	size_t entry_size;	// amount of bytes occupied in cache by this record
+	bool valid;		// fields further down are valid (ignore them if false)
+	int64_t expires_in;	// < 0 => already expired
+	uint16_t rrtype;
+	uint8_t no_labels;	// 0 == ., 1 == root zone member, 2 == TLD member ...
+	uint8_t rank;
+} gc_record_info_t;
+
+typedef struct {
+	const char *cache_path;	// path to the LMDB with resolver cache
+	unsigned long gc_interval;	// waiting time between two whole garbage collections in usecs (0 = just one-time cleanup)
+
+	size_t temp_keys_space;	// maximum amount of temporary memory for copied keys in bytes (0 = unlimited)
+
+	size_t rw_txn_items;	// maximum number of deleted records per RW transaction (0 = unlimited)
+	size_t ro_txn_items;	// maximum number of iterated records (RO transactions, 0 = unlimited)
+	unsigned long rw_txn_duration;	// maximum duration of RW transaction in usecs (0 = unlimited)
+	unsigned long rw_txn_delay;	// waiting time between two RW transactions in usecs
+
+	uint8_t cache_max_usage;	// maximum cache usage before triggering GC (percent)
+	uint8_t cache_to_be_freed;	// percent of current cache usage to be freed during GC
+
+	bool dry_run;
+} kr_cache_gc_cfg_t;
+
+/** State persisting across kr_cache_gc() invocations (opaque).
+ * NULL pointer represents a clean state. */
+typedef struct kr_cache_gc_state kr_cache_gc_state_t;
+
+/** Do one iteration of cache-size check and (if necessary) GC pass. */
+int kr_cache_gc(kr_cache_gc_cfg_t *cfg, kr_cache_gc_state_t **state);
+void kr_cache_gc_free_state(kr_cache_gc_state_t **state);
+