#endif
#include <ccan/compiler/compiler.h>
#include <ccan/typesafe_cb/typesafe_cb.h>
+#include <ccan/cast/cast.h>
union tdb_attribute;
struct tdb_context;
#define TDB_NOMMAP 8 /* don't use mmap */
#define TDB_CONVERT 16 /* convert endian */
#define TDB_NOSYNC 64 /* don't use synchronous transactions */
+#define TDB_SEQNUM 128 /* maintain a sequence number */
/**
* tdb_close - close and free a tdb.
return a.dsize == b.dsize && memcmp(a.dptr, b.dptr, a.dsize) == 0;
}
+/**
+ * tdb_mkdata - make a struct tdb_data from const data
+ * @p: the constant pointer
+ * @len: the length
+ *
+ * As the dptr member of struct tdb_data is not constant, you need to
+ * cast it. This function keeps thost casts in one place, as well as
+ * suppressing the warning some compilers give when casting away a
+ * qualifier (eg. gcc with -Wcast-qual)
+ */
+static inline struct tdb_data tdb_mkdata(const void *p, size_t len)
+{
+ struct tdb_data d;
+ d.dptr = cast_const(void *, p);
+ d.dsize = len;
+ return d;
+}
+
/**
* tdb_transaction_start - start a transaction
* @tdb: the tdb context returned from tdb_open()
* a negative enum TDB_ERROR value.
*/
#define tdb_traverse(tdb, fn, p) \
- tdb_traverse_(tdb, typesafe_cb_preargs(int, (fn), (p), \
+ tdb_traverse_(tdb, typesafe_cb_preargs(int, void *, (fn), (p), \
struct tdb_context *, \
TDB_DATA, TDB_DATA), (p))
*/
#define tdb_parse_record(tdb, key, parse, p) \
tdb_parse_record_((tdb), (key), \
- typesafe_cb_preargs(enum TDB_ERROR, (parse), (p), \
+ typesafe_cb_preargs(enum TDB_ERROR, void *, \
+ (parse), (p), \
TDB_DATA, TDB_DATA), (p))
enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
TDB_DATA data,
void *p),
void *p);
+
+/**
+ * tdb_get_seqnum - get a database sequence number
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * This returns a sequence number: any change to the database from a
+ * tdb context opened with the TDB_SEQNUM flag will cause that number
+ * to increment. Note that the incrementing is unreliable (it is done
+ * without locking), so this is only useful as an optimization.
+ *
+ * For example, you may have a regular database backup routine which
+ * does not operate if the sequence number is unchanged. In the
+ * unlikely event of a failed increment, it will be backed up next
+ * time any way.
+ *
+ * Returns an enum TDB_ERROR (ie. negative) on error.
+ */
+int64_t tdb_get_seqnum(struct tdb_context *tdb);
+
/**
* tdb_firstkey - get the "first" key in a TDB
* @tdb: the tdb context returned from tdb_open()
* @tdb: the tdb context returned from tdb_open()
* @key: the key to lock.
*
- * This prevents any changes from occurring to a group of keys including @key,
+ * This prevents any access occurring to a group of keys including @key,
* even if @key does not exist. This allows primitive atomic updates of
* records without using transactions.
*
* tdb_chainunlock - unlock a record in the TDB
* @tdb: the tdb context returned from tdb_open()
* @key: the key to unlock.
+ *
+ * The key must have previously been locked by tdb_chainlock().
+ */
+void tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * tdb_chainlock_read - lock a record in the TDB, for reading
+ * @tdb: the tdb context returned from tdb_open()
+ * @key: the key to lock.
+ *
+ * This prevents any changes from occurring to a group of keys including @key,
+ * even if @key does not exist. This allows primitive atomic updates of
+ * records without using transactions.
+ *
+ * You cannot begin a transaction while holding a tdb_chainlock_read(), nor can
+ * you do any operations on any other keys in the database. This also means
+ * that you cannot hold more than one tdb_chainlock()/read() at a time.
+ *
+ * See Also:
+ * tdb_chainlock()
+ */
+enum TDB_ERROR tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * tdb_chainunlock_read - unlock a record in the TDB for reading
+ * @tdb: the tdb context returned from tdb_open()
+ * @key: the key to unlock.
+ *
+ * The key must have previously been locked by tdb_chainlock_read().
+ */
+void tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key);
+
+/**
+ * tdb_lockall - lock the entire TDB
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * You cannot hold a tdb_chainlock while calling this. It nests, so you
+ * must call tdb_unlockall as many times as you call tdb_lockall.
+ */
+enum TDB_ERROR tdb_lockall(struct tdb_context *tdb);
+
+/**
+ * tdb_unlockall - unlock the entire TDB
+ * @tdb: the tdb context returned from tdb_open()
+ */
+void tdb_unlockall(struct tdb_context *tdb);
+
+/**
+ * tdb_lockall_read - lock the entire TDB for reading
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * This prevents others writing to the database, eg. tdb_delete, tdb_store,
+ * tdb_append, but not tdb_fetch.
+ *
+ * You cannot hold a tdb_chainlock while calling this. It nests, so you
+ * must call tdb_unlockall_read as many times as you call tdb_lockall_read.
*/
-enum TDB_ERROR tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key);
+enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb);
+
+/**
+ * tdb_unlockall_read - unlock the entire TDB for reading
+ * @tdb: the tdb context returned from tdb_open()
+ */
+void tdb_unlockall_read(struct tdb_context *tdb);
/**
* tdb_wipe_all - wipe the database clean
* tdb_check - check a TDB for consistency
* @tdb: the tdb context returned from tdb_open()
* @check: function to check each key/data pair (or NULL)
- * @private: argument for @check, must match type.
+ * @private_data: argument for @check, must match type.
*
* This performs a consistency check of the open database, optionally calling
* a check() function on each record so you can do your own data consistency
*
* Returns TDB_SUCCESS or an error.
*/
-#define tdb_check(tdb, check, private) \
- tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, \
- (check), (private), \
+#define tdb_check(tdb, check, private_data) \
+ tdb_check_((tdb), typesafe_cb_preargs(enum TDB_ERROR, void *, \
+ (check), (private_data), \
struct tdb_data, \
struct tdb_data), \
- (private))
+ (private_data))
enum TDB_ERROR tdb_check_(struct tdb_context *tdb,
enum TDB_ERROR (*check)(struct tdb_data key,
struct tdb_data data,
- void *private),
- void *private);
+ void *private_data),
+ void *private_data);
+
+/**
+ * tdb_error - get the last error (not threadsafe)
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * Returns the last error returned by a TDB function.
+ *
+ * This makes porting from TDB1 easier, but note that the last error is not
+ * reliable in threaded programs.
+ */
+enum TDB_ERROR tdb_error(struct tdb_context *tdb);
/**
* enum tdb_summary_flags - flags for tdb_summary.
projects / ccan / blobdiff