tdb2: expose and document tdb1_incompatible_hash.

[ccan] / ccan / tdb2 / tdb2.h

diff --git a/ccan/tdb2/tdb2.h b/ccan/tdb2/tdb2.h
index d5ae329a6029d7659886992dd380e845bd9d2fb4..be5d50027712d4cf511ce60b02ae5e95bfc850e1 100644 (file)
--- a/ccan/tdb2/tdb2.h
+++ b/ccan/tdb2/tdb2.h
@@ -86,6 +86,19 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 #define TDB_SEQNUM   128 /* maintain a sequence number */
 #define TDB_ALLOW_NESTING   256 /* fake nested transactions */
 #define TDB_RDONLY   512 /* implied by O_RDONLY */
+#define TDB_VERSION1  1024 /* create/open an old style TDB */
+
+/**
+ * tdb1_incompatible_hash - better (Jenkins) hash for tdb1
+ *
+ * This is better than the default hash for tdb1; but older versions of the
+ * tdb library (prior to version 1.2.6) won't be able to open them.
+ *
+ * It only makes sense to specify this (using tdb_attribute_hash) when
+ * creating (with O_CREAT) an old tdb version using TDB_VERSION1.  It's
+ * equivalent to the TDB_INCOMPATIBLE_HASH flag for tdb1.
+ */
+uint64_t tdb1_incompatible_hash(const void *, size_t, uint64_t, void *);
 
 /**
  * tdb_close - close and free a tdb.
@@ -504,6 +517,16 @@ void tdb_unlockall_read(struct tdb_context *tdb);
  */
 enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb);
 
+/**
+ * tdb_repack - repack the database
+ * @tdb: the tdb context returned from tdb_open()
+ *
+ * This repacks the database; if it is suffering from a great deal of
+ * fragmentation this might help.  However, it can take twice the
+ * memory of the existing TDB.
+ */
+enum TDB_ERROR tdb_repack(struct tdb_context *tdb);
+
 /**
  * tdb_check - check a TDB for consistency
  * @tdb: the tdb context returned from tdb_open()
@@ -606,7 +629,8 @@ enum tdb_attribute_type {
        TDB_ATTRIBUTE_SEED = 2,
        TDB_ATTRIBUTE_STATS = 3,
        TDB_ATTRIBUTE_OPENHOOK = 4,
-       TDB_ATTRIBUTE_FLOCK = 5
+       TDB_ATTRIBUTE_FLOCK = 5,
+       TDB_ATTRIBUTE_TDB1_HASHSIZE = 128,
 };
 
 /**
@@ -630,8 +654,9 @@ enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb,
  * of the same type.  It returns TDB_ERR_EINVAL if the attribute is
  * unknown or invalid.
  *
- * Note that TDB_ATTRIBUTE_HASH, TDB_ATTRIBUTE_SEED and
- * TDB_ATTRIBUTE_OPENHOOK cannot currently be set after tdb_open.
+ * Note that TDB_ATTRIBUTE_HASH, TDB_ATTRIBUTE_SEED,
+ * TDB_ATTRIBUTE_OPENHOOK and TDB_ATTRIBUTE_TDB1_HASHSIZE cannot
+ * currently be set after tdb_open.
  */
 enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb,
                                 const union tdb_attribute *attr);
@@ -837,6 +862,19 @@ struct tdb_attribute_flock {
        void *data;
 };
 
+/**
+ * struct tdb_attribute_tdb1_hashsize - tdb1 hashsize
+ *
+ * This attribute allows setting the TDB1 hashsize; it only makes sense with
+ * O_CREAT and TDB_VERSION1.
+ *
+ * Hashsize should generally be a prime, such as 10007.
+ */
+struct tdb_attribute_tdb1_hashsize {
+       struct tdb_attribute_base base; /* .attr = TDB_ATTRIBUTE_TDB1_HASHSIZE */
+       unsigned int hsize;
+};
+
 /**
  * union tdb_attribute - tdb attributes.
  *
@@ -855,6 +893,7 @@ union tdb_attribute {
        struct tdb_attribute_stats stats;
        struct tdb_attribute_openhook openhook;
        struct tdb_attribute_flock flock;
+       struct tdb_attribute_tdb1_hashsize tdb1_hashsize;
 };
 
 #ifdef  __cplusplus