/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998
 *      Sleepycat Software.  All rights reserved.
 *
 *      @(#)txn.h       10.18 (Sleepycat) 1/3/99
 */
#ifndef _TXN_H_
#define _TXN_H_

#include "xa.h"

/*
 * The name of the transaction shared memory region is DEFAULT_TXN_FILE and
 * the region is always created group RW of the group owning the directory.
 */
#define DEFAULT_TXN_FILE        "__db_txn.share"
/* TXN_MINIMUM = (DB_LOCK_MAXID + 1) but this makes compilers complain. */
#define TXN_MINIMUM             0x80000000
#define TXN_INVALID             0xffffffff /* Maximum number of txn ids. */

/*
 * Transaction type declarations.
 */

/*
 * Internal data maintained in shared memory for each transaction.
 */
typedef char DB_XID[XIDDATASIZE];

typedef struct __txn_detail {
        u_int32_t txnid;                /* current transaction id
                                           used to link free list also */
        DB_LSN  last_lsn;               /* last lsn written for this txn */
        DB_LSN  begin_lsn;              /* lsn of begin record */
        size_t  last_lock;              /* offset in lock region of last lock
                                           for this transaction. */
        size_t  parent;                 /* Offset of transaction's parent. */
#define TXN_UNALLOC     0
#define TXN_RUNNING     1
#define TXN_ABORTED     2
#define TXN_PREPARED    3
#define TXN_COMMITTED   4
        u_int32_t status;               /* status of the transaction */
        SH_TAILQ_ENTRY  links;          /* free/active list */

#define TXN_XA_ABORTED          1
#define TXN_XA_DEADLOCKED       2
#define TXN_XA_ENDED            3
#define TXN_XA_PREPARED         4
#define TXN_XA_STARTED          5
#define TXN_XA_SUSPENDED        6
        u_int32_t xa_status;            /* XA status */

        /*
         * XID (xid_t) structure: because these fields are logged, the
         * sizes have to be explicit.
         */
        DB_XID xid;                     /* XA global transaction id */
        u_int32_t bqual;                /* bqual_length from XID */
        u_int32_t gtrid;                /* gtrid_length from XID */
        int32_t format;                 /* XA format */
} TXN_DETAIL;

/*
 * The transaction manager encapsulates the transaction system.  It contains
 * references to the log and lock managers as well as the state that keeps
 * track of the shared memory region.
 */
struct __db_txnmgr {
/* These fields need to be protected for multi-threaded support. */
        db_mutex_t      *mutexp;        /* Synchronization. */
                                        /* list of active transactions */
        TAILQ_HEAD(_chain, __db_txn)    txn_chain;

/* These fields are not protected. */
        REGINFO         reginfo;        /* Region information. */
        DB_ENV          *dbenv;         /* Environment. */
        int (*recover)                  /* Recovery dispatch routine */
            __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
        u_int32_t        flags;         /* DB_TXN_NOSYNC, DB_THREAD */
        DB_TXNREGION    *region;        /* address of shared memory region */
        void            *mem;           /* address of the shalloc space */
};

/*
 * Layout of the shared memory region.
 * The region consists of a DB_TXNREGION structure followed by a large
 * pool of shalloc'd memory which is used to hold TXN_DETAIL structures
 * and thread mutexes (which are dynamically allocated).
 */
struct __db_txnregion {
        RLAYOUT         hdr;            /* Shared memory region header. */
        u_int32_t       magic;          /* transaction magic number */
        u_int32_t       version;        /* version number */
        u_int32_t       maxtxns;        /* maximum number of active txns */
        u_int32_t       last_txnid;     /* last transaction id given out */
        DB_LSN          pending_ckp;    /* last checkpoint did not finish */
        DB_LSN          last_ckp;       /* lsn of the last checkpoint */
        time_t          time_ckp;       /* time of last checkpoint */
        u_int32_t       logtype;        /* type of logging */
        u_int32_t       locktype;       /* lock type */
        u_int32_t       naborts;        /* number of aborted transactions */
        u_int32_t       ncommits;       /* number of committed transactions */
        u_int32_t       nbegins;        /* number of begun transactions */
        SH_TAILQ_HEAD(_active) active_txn;      /* active transaction list */
};

/*
 * Make the region large enough to hold N  transaction detail structures
 * plus some space to hold thread handles and the beginning of the shalloc
 * region.
 */
#define TXN_REGION_SIZE(N)                                              \
        (sizeof(DB_TXNREGION) + N * sizeof(TXN_DETAIL) + 1000)

/* Macros to lock/unlock the region and threads. */
#define LOCK_TXNTHREAD(tmgrp)                                           \
        if (F_ISSET(tmgrp, DB_THREAD))                                  \
                (void)__db_mutex_lock((tmgrp)->mutexp, -1)
#define UNLOCK_TXNTHREAD(tmgrp)                                         \
        if (F_ISSET(tmgrp, DB_THREAD))                                  \
                (void)__db_mutex_unlock((tmgrp)->mutexp, -1)

#define LOCK_TXNREGION(tmgrp)                                           \
        (void)__db_mutex_lock(&(tmgrp)->region->hdr.lock, (tmgrp)->reginfo.fd)
#define UNLOCK_TXNREGION(tmgrp)                                         \
        (void)__db_mutex_unlock(&(tmgrp)->region->hdr.lock, (tmgrp)->reginfo.fd)

/* Check for region catastrophic shutdown. */
#define TXN_PANIC_CHECK(tmgrp) {                                        \
        if ((tmgrp)->region->hdr.panic)                                 \
                return (DB_RUNRECOVERY);                                \
}

/*
 * Log record types.
 */
#define TXN_COMMIT      1
#define TXN_PREPARE     2
#define TXN_CHECKPOINT  3

#include "txn_auto.h"
#include "txn_ext.h"

#include "xa_ext.h"
#endif /* !_TXN_H_ */