Add mdb.c:txnid_t for readability.

Maybe later we'll test txnid wraparound with it defined to ushort.

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index 1a539ba..0c1329e 100644 (file)
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -168,6 +168,11 @@
         */
 typedef ULONG          pgno_t;
 
+       /** A transaction ID.
+        *      See struct MDB_txn.mt_txnid for details.
+        */
+typedef ULONG          txnid_t;
+
 /** @defgroup debug    Debug Macros
  *     @{
  */
@@ -382,7 +387,7 @@ typedef struct MDB_rxbody {
         *      started from so we can avoid overwriting any data used in that
         *      particular version.
         */
-       ULONG           mrb_txnid;
+       txnid_t         mrb_txnid;
        /** The process ID of the process owning this reader txn. */
        pid_t           mrb_pid;
        /** The thread ID of the thread owning this txn. */
@@ -431,7 +436,7 @@ typedef struct MDB_txbody {
                 *      This is recorded here only for convenience; the value can always
                 *      be determined by reading the main database meta pages.
                 */
-       ULONG           mtb_txnid;
+       txnid_t         mtb_txnid;
                /** The number of slots that have been used in the reader table.
                 *      This always records the maximum count, it is not decremented
                 *      when readers release their slots.
@@ -641,7 +646,7 @@ typedef struct MDB_meta {
        /** Any persistent environment flags. @ref mdb_env */
 #define        mm_flags        mm_dbs[0].md_flags
        pgno_t          mm_last_pg;                     /**< last used page in file */
-       ULONG           mm_txnid;                       /**< txnid that committed this page */
+       txnid_t         mm_txnid;                       /**< txnid that committed this page */
 } MDB_meta;
 
        /** Auxiliary DB info.
@@ -669,7 +674,7 @@ struct MDB_txn {
         *      Only committed write transactions increment the ID. If a transaction
         *      aborts, the ID may be re-used by the next writer.
         */
-       ULONG           mt_txnid;
+       txnid_t         mt_txnid;
        MDB_env         *mt_env;                /**< the DB environment */
        /** The list of pages that became unused during this transaction.
         *      This is an #IDL.
@@ -754,7 +759,7 @@ typedef struct MDB_oldpages {
         */
        struct MDB_oldpages *mo_next;
        /**     The ID of the transaction in which these pages were freed. */
-       ULONG           mo_txnid;
+       txnid_t         mo_txnid;
        /** An #IDL of the pages */
        pgno_t          mo_pages[1];    /* dynamic */
 } MDB_oldpages;
@@ -966,7 +971,7 @@ mdb_alloc_page(MDB_cursor *mc, int num)
                        /* See if there's anything in the free DB */
                        MDB_cursor m2;
                        MDB_node *leaf;
-                       ULONG *kptr, oldest;
+                       txnid_t *kptr, oldest;
 
                        m2.mc_txn = txn;
                        m2.mc_dbi = FREE_DBI;
@@ -974,13 +979,13 @@ mdb_alloc_page(MDB_cursor *mc, int num)
                        m2.mc_flags = 0;
                        mdb_search_page(&m2, NULL, 0);
                        leaf = NODEPTR(m2.mc_pg[m2.mc_top], 0);
-                       kptr = (ULONG *)NODEKEY(leaf);
+                       kptr = (txnid_t *)NODEKEY(leaf);
 
                        {
                                unsigned int i;
                                oldest = txn->mt_txnid - 1;
                                for (i=0; i<txn->mt_env->me_txns->mti_numreaders; i++) {
-                                       ULONG mr = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
+                                       txnid_t mr = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
                                        if (mr && mr < oldest)
                                                oldest = mr;
                                }
@@ -1374,7 +1379,7 @@ mdb_txn_commit(MDB_txn *txn)
 #endif
                /* write to last page of freeDB */
                key.mv_size = sizeof(pgno_t);
-               key.mv_data = (char *)&txn->mt_txnid;
+               key.mv_data = &txn->mt_txnid;
                data.mv_data = txn->mt_free_pgs;
                /* The free list can still grow during this call,
                 * despite the pre-emptive touches above. So check
@@ -1397,7 +1402,7 @@ mdb_txn_commit(MDB_txn *txn)
 
                mop = env->me_pghead;
                key.mv_size = sizeof(pgno_t);
-               key.mv_data = (char *)&mop->mo_txnid;
+               key.mv_data = &mop->mo_txnid;
                data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
                data.mv_data = mop->mo_pages;
                mdb_cursor_put(&mc, &key, &data, 0);