namedb: support more flags / operations

src/common/namedb/namedb.h

@@ -21,8 +21,16 @@
 #include "common/mempattern.h"
 
 enum {
-	KNOT_NAMEDB_RDONLY = 1 << 0,
-	KNOT_NAMEDB_SORTED = 1 << 1
+	KNOT_NAMEDB_RDONLY = 1 << 0, /*< Read only. */
+	KNOT_NAMEDB_SORTED = 1 << 1, /*< Sorted output. */
+	
+	KNOT_NAMEDB_NOOP   = 1 << 2, /*< No operation. */
+	KNOT_NAMEDB_FIRST  = 1 << 3, /*!< First entry. */
+	KNOT_NAMEDB_LAST   = 1 << 4, /*!< Last entry. */
+	KNOT_NAMEDB_NEXT   = 1 << 5, /*!< Next entry. */
+	KNOT_NAMEDB_PREV   = 1 << 6, /*!< Previous entry. */
+	KNOT_NAMEDB_LEQ    = 1 << 7, /*!< Lesser or equal. */
+	KNOT_NAMEDB_GEQ    = 1 << 8  /*!< Greater or equal. */
 };
 
 typedef void knot_namedb_t;

src/common/namedb/namedb_lmdb.c

@@ -282,14 +282,11 @@ static knot_iter_t *iter_begin(knot_txn_t *txn, unsigned flags)
 	if (ret != 0) {
 		return NULL;
 	}
-
-	ret = mdb_cursor_get(cursor, NULL, NULL, MDB_FIRST);
-	if (ret != 0) {
-		mdb_cursor_close(cursor);
-		return NULL;
-	}
-
-	return cursor;
+	
+	/* Clear sorted flag, as it's always sorted. */
+	flags &= ~KNOT_NAMEDB_SORTED;
+	
+	return iter_set(cursor, NULL, (flags == 0) ? KNOT_NAMEDB_FIRST : flags);
 }
 
 static knot_iter_t *iter_next(knot_iter_t *iter)

src/common/namedb/namedb_trie.c

@@ -98,7 +98,16 @@ static int del(knot_txn_t *txn, knot_val_t *key)
 
 static knot_iter_t *iter_begin(knot_txn_t *txn, unsigned flags)
 {
-	return hattrie_iter_begin((hattrie_t *)txn->db, (flags & KNOT_NAMEDB_SORTED));
+	bool is_sorted = (flags & KNOT_NAMEDB_SORTED);
+	flags &= ~KNOT_NAMEDB_SORTED;
+	
+	/* No operations other than begin are supported right now. */
+	if (flags != 0) {
+		return NULL;
+	}
+	
+	return hattrie_iter_begin((hattrie_t *)txn->db, is_sorted);
+}
 }
 
 static knot_iter_t *iter_next(knot_iter_t *iter)