diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c index 8769ebb..94a650d 100644 --- a/libraries/libmdb/mdb.c +++ b/libraries/libmdb/mdb.c @@ -662,6 +662,7 @@ typedef struct MDB_dbx { MDB_cmp_func *md_cmp; /**< function for comparing keys */ MDB_cmp_func *md_dcmp; /**< function for comparing data items */ MDB_rel_func *md_rel; /**< user relocate function */ + void *md_relctx; /**< user-provided context for md_rel */ MDB_dbi md_parent; /**< parent DB of a sub-DB */ unsigned int md_dirty; /**< TRUE if DB was written in this txn */ } MDB_dbx; @@ -923,15 +924,6 @@ mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b) return txn->mt_dbxs[dbi].md_cmp(a, b); } -/** Compare two data items according to a particular database. - * This returns a comparison as if the two items were data items of - * a sorted duplicates #MDB_DUPSORT database. - * @param[in] txn A transaction handle returned by #mdb_txn_begin() - * @param[in] dbi A database handle returned by #mdb_open() - * @param[in] a The first item to compare - * @param[in] b The second item to compare - * @return < 0 if a < b, 0 if a == b, > 0 if a > b - */ int mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b) { @@ -4731,4 +4723,13 @@ int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel) return MDB_SUCCESS; } +int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx) +{ + if (txn == NULL || !dbi || dbi >= txn->mt_numdbs) + return EINVAL; + + txn->mt_dbxs[dbi].md_relctx = ctx; + return MDB_SUCCESS; +} + /** @} */ diff --git a/libraries/libmdb/mdb.h b/libraries/libmdb/mdb.h index ce3137c..b99ece7 100644 --- a/libraries/libmdb/mdb.h +++ b/libraries/libmdb/mdb.h @@ -125,13 +125,18 @@ typedef struct MDB_val { typedef int (MDB_cmp_func)(const MDB_val *a, const MDB_val *b); /** A callback function used to relocate a position-dependent data item - * in a fixed-address database. The \b newptr gives the item's current address in - * the memory map, and \b oldptr gives its previous address. This callback is - * expected to walk through the fields of the record in newptr and modify any + * in a fixed-address database. The \b newptr gives the item's desired address in + * the memory map, and \b oldptr gives its previous address. The item's actual + * data resides at the address in \b item. This callback is expected to walk + * through the fields of the record in \b item and modify any * values based at the \b oldptr address to be relative to the \b newptr address. + * @param[in,out] item The item that is to be relocated. + * @param[in] oldptr The previous address. + * @param[in] newptr The new address to relocate to. + * @param[in] relctx An application-provided context, set by #mdb_set_relctx(). * @todo This feature is currently unimplemented. */ -typedef void (MDB_rel_func)(void *newptr, void *oldptr, size_t size); +typedef void (MDB_rel_func)(MDB_val *item, void *oldptr, void *newptr, void *relctx); /** @defgroup mdb_env Environment Flags * @{ @@ -178,7 +183,10 @@ typedef void (MDB_rel_func)(void *newptr, void *oldptr, size_t size); #define MDB_CURRENT 0x40 /* @} */ -/** Cursor operations */ +/** Cursor Get operations + * This is the set of all operations for retrieving data + * using a cursor. + */ typedef enum MDB_cursor_op { MDB_FIRST, /**< Position at first key/data item */ MDB_FIRST_DUP, /**< Position at first data item of current key. @@ -596,8 +604,8 @@ void mdb_close(MDB_txn *txn, MDB_dbi dbi); * with #mdb_open(), the keys are compared lexically, with shorter keys collating * before longer keys. * @warning This function must be called before any data access functions are used, - * otherwise data corruption may occur. The same function must be used by every - * process accessing the database, every time the database is used. + * otherwise data corruption may occur. The same comparison function must be used by every + * program accessing the database, every time the database is used. * @param[in] txn A transaction handle returned by #mdb_txn_begin() * @param[in] dbi A database handle returned by #mdb_open() * @param[in] cmp A #MDB_cmp_func function @@ -618,8 +626,8 @@ int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp); * with #mdb_open(), the data items are compared lexically, with shorter items collating * before longer items. * @warning This function must be called before any data access functions are used, - * otherwise data corruption may occur. The same function must be used by every - * process accessing the database, every time the database is used. + * otherwise data corruption may occur. The same comparison function must be used by every + * program accessing the database, every time the database is used. * @param[in] txn A transaction handle returned by #mdb_txn_begin() * @param[in] dbi A database handle returned by #mdb_open() * @param[in] cmp A #MDB_cmp_func function @@ -650,6 +658,21 @@ int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp); */ int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel); + /** Set a context pointer for a #MDB_FIXEDMAP database's relocation function. + * See #mdb_set_relfunc and #MDB_rel_func for more details. + * @param[in] txn A transaction handle returned by #mdb_txn_begin() + * @param[in] dbi A database handle returned by #mdb_open() + * @param[in] ctx An arbitrary pointer for whatever the application needs. + * It will be passed to the callback function set by #mdb_set_relfunc + * as its \b relctx parameter whenever the callback is invoked. + * @return A non-zero error value on failure and 0 on success. Some possible + * errors are: + * + */ +int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx); + /** Get items from a database. * This function retrieves key/data pairs from the database. The address * and length of the data associated with the specified \b key are returned @@ -852,5 +875,15 @@ int mdb_cursor_count(MDB_cursor *cursor, size_t *countp); */ int mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b); + /** Compare two data items according to a particular database. + * This returns a comparison as if the two items were data items of + * a sorted duplicates #MDB_DUPSORT database. + * @param[in] txn A transaction handle returned by #mdb_txn_begin() + * @param[in] dbi A database handle returned by #mdb_open() + * @param[in] a The first item to compare + * @param[in] b The second item to compare + * @return < 0 if a < b, 0 if a == b, > 0 if a > b + */ +int mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b); /** @} */ #endif /* _MDB_H_ */