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db_cam.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2000-2003
 *    Sleepycat Software.  All rights reserved.
 */

#include "db_config.h"

#ifndef lint
static const char revid[] = "$Id: db_cam.c,v 11.140 2003/11/18 18:20:48 mjc Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/db_shash.h"
#include "dbinc/btree.h"
#include "dbinc/hash.h"
#include "dbinc/lock.h"
#include "dbinc/mp.h"
#include "dbinc/qam.h"

static int __db_buildpartial __P((DB *, DBT *, DBT *, DBT *));
static int __db_c_cleanup __P((DBC *, DBC *, int));
static int __db_c_del_secondary __P((DBC *));
static int __db_c_pget_recno __P((DBC *, DBT *, DBT *, u_int32_t));
static int __db_wrlock_err __P((DB_ENV *));

#define     CDB_LOCKING_INIT(dbp, dbc)                            \
      /*                                              \
       * If we are running CDB, this had better be either a write \
       * cursor or an immediate writer.  If it's a regular writer,      \
       * that means we have an IWRITE lock and we need to upgrade \
       * it to a write lock.                                \
       */                                             \
      if (CDB_LOCKING((dbp)->dbenv)) {                      \
            if (!F_ISSET(dbc, DBC_WRITECURSOR | DBC_WRITER))      \
                  return (__db_wrlock_err(dbp->dbenv));           \
                                                      \
            if (F_ISSET(dbc, DBC_WRITECURSOR) &&                  \
                (ret = __lock_get((dbp)->dbenv,             \
                (dbc)->locker, DB_LOCK_UPGRADE, &(dbc)->lock_dbt, \
                DB_LOCK_WRITE, &(dbc)->mylock)) != 0)       \
                  return (ret);                             \
      }
#define     CDB_LOCKING_DONE(dbp, dbc)                            \
      /* Release the upgraded lock. */                      \
      if (F_ISSET(dbc, DBC_WRITECURSOR))                    \
            (void)__lock_downgrade(                         \
                (dbp)->dbenv, &(dbc)->mylock, DB_LOCK_IWRITE, 0);
/*
 * __db_c_close --
 *    DBC->c_close.
 *
 * PUBLIC: int __db_c_close __P((DBC *));
 */
int
__db_c_close(dbc)
      DBC *dbc;
{
      DB *dbp;
      DBC *opd;
      DBC_INTERNAL *cp;
      DB_ENV *dbenv;
      int ret, t_ret;

      dbp = dbc->dbp;
      dbenv = dbp->dbenv;
      cp = dbc->internal;
      opd = cp->opd;
      ret = 0;

      /*
       * Remove the cursor(s) from the active queue.  We may be closing two
       * cursors at once here, a top-level one and a lower-level, off-page
       * duplicate one.  The acess-method specific cursor close routine must
       * close both of them in a single call.
       *
       * !!!
       * Cursors must be removed from the active queue before calling the
       * access specific cursor close routine, btree depends on having that
       * order of operations.
       */
      MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);

      if (opd != NULL) {
            F_CLR(opd, DBC_ACTIVE);
            TAILQ_REMOVE(&dbp->active_queue, opd, links);
      }
      F_CLR(dbc, DBC_ACTIVE);
      TAILQ_REMOVE(&dbp->active_queue, dbc, links);

      MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);

      /* Call the access specific cursor close routine. */
      if ((t_ret =
          dbc->c_am_close(dbc, PGNO_INVALID, NULL)) != 0 && ret == 0)
            ret = t_ret;

      /*
       * Release the lock after calling the access method specific close
       * routine, a Btree cursor may have had pending deletes.
       */
      if (CDB_LOCKING(dbenv)) {
            /*
             * Also, be sure not to free anything if mylock.off is
             * INVALID;  in some cases, such as idup'ed read cursors
             * and secondary update cursors, a cursor in a CDB
             * environment may not have a lock at all.
             */
            if (LOCK_ISSET(dbc->mylock)) {
                  if ((t_ret = __lock_put(
                      dbenv, &dbc->mylock)) != 0 && ret == 0)
                        ret = t_ret;
            }

            /* For safety's sake, since this is going on the free queue. */
            memset(&dbc->mylock, 0, sizeof(dbc->mylock));
            if (opd != NULL)
                  memset(&opd->mylock, 0, sizeof(opd->mylock));
      }

      if (dbc->txn != NULL)
            dbc->txn->cursors--;

      /* Move the cursor(s) to the free queue. */
      MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
      if (opd != NULL) {
            if (dbc->txn != NULL)
                  dbc->txn->cursors--;
            TAILQ_INSERT_TAIL(&dbp->free_queue, opd, links);
            opd = NULL;
      }
      TAILQ_INSERT_TAIL(&dbp->free_queue, dbc, links);
      MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);

      return (ret);
}

/*
 * __db_c_destroy --
 *    Destroy the cursor, called after DBC->c_close.
 *
 * PUBLIC: int __db_c_destroy __P((DBC *));
 */
int
__db_c_destroy(dbc)
      DBC *dbc;
{
      DB *dbp;
      DB_ENV *dbenv;
      int ret, t_ret;

      dbp = dbc->dbp;
      dbenv = dbp->dbenv;

      /* Remove the cursor from the free queue. */
      MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
      TAILQ_REMOVE(&dbp->free_queue, dbc, links);
      MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);

      /* Free up allocated memory. */
      if (dbc->my_rskey.data != NULL)
            __os_free(dbenv, dbc->my_rskey.data);
      if (dbc->my_rkey.data != NULL)
            __os_free(dbenv, dbc->my_rkey.data);
      if (dbc->my_rdata.data != NULL)
            __os_free(dbenv, dbc->my_rdata.data);

      /* Call the access specific cursor destroy routine. */
      ret = dbc->c_am_destroy == NULL ? 0 : dbc->c_am_destroy(dbc);

      /*
       * Release the lock id for this cursor.
       */
      if (LOCKING_ON(dbenv) &&
          F_ISSET(dbc, DBC_OWN_LID) &&
          (t_ret = __lock_id_free(dbenv, dbc->lid)) != 0 && ret == 0)
            ret = t_ret;

      __os_free(dbenv, dbc);

      return (ret);
}

/*
 * __db_c_count --
 *    Return a count of duplicate data items.
 *
 * PUBLIC: int __db_c_count __P((DBC *, db_recno_t *));
 */
int
__db_c_count(dbc, recnop)
      DBC *dbc;
      db_recno_t *recnop;
{
      DB_ENV *dbenv;
      int ret;

      dbenv = dbc->dbp->dbenv;

      /*
       * Cursor Cleanup Note:
       * All of the cursors passed to the underlying access methods by this
       * routine are not duplicated and will not be cleaned up on return.
       * So, pages/locks that the cursor references must be resolved by the
       * underlying functions.
       */
      switch (dbc->dbtype) {
      case DB_QUEUE:
      case DB_RECNO:
            *recnop = 1;
            break;
      case DB_HASH:
            if (dbc->internal->opd == NULL) {
                  if ((ret = __ham_c_count(dbc, recnop)) != 0)
                        return (ret);
                  break;
            }
            /* FALLTHROUGH */
      case DB_BTREE:
            if ((ret = __bam_c_count(dbc, recnop)) != 0)
                  return (ret);
            break;
      case DB_UNKNOWN:
      default:
            return (__db_unknown_type(dbenv, "__db_c_count", dbc->dbtype));
      }
      return (0);
}

/*
 * __db_c_del --
 *    DBC->c_del.
 *
 * PUBLIC: int __db_c_del __P((DBC *, u_int32_t));
 */
int
__db_c_del(dbc, flags)
      DBC *dbc;
      u_int32_t flags;
{
      DB *dbp;
      DBC *opd;
      int ret;

      dbp = dbc->dbp;

      /*
       * Cursor Cleanup Note:
       * All of the cursors passed to the underlying access methods by this
       * routine are not duplicated and will not be cleaned up on return.
       * So, pages/locks that the cursor references must be resolved by the
       * underlying functions.
       */

      CDB_LOCKING_INIT(dbp, dbc);

      /*
       * If we're a secondary index, and DB_UPDATE_SECONDARY isn't set
       * (which it only is if we're being called from a primary update),
       * then we need to call through to the primary and delete the item.
       *
       * Note that this will delete the current item;  we don't need to
       * delete it ourselves as well, so we can just goto done.
       */
      if (flags != DB_UPDATE_SECONDARY && F_ISSET(dbp, DB_AM_SECONDARY)) {
            ret = __db_c_del_secondary(dbc);
            goto done;
      }

      /*
       * If we are a primary and have secondary indices, go through
       * and delete any secondary keys that point at the current record.
       */
      if (LIST_FIRST(&dbp->s_secondaries) != NULL &&
          (ret = __db_c_del_primary(dbc)) != 0)
            goto done;

      /*
       * Off-page duplicate trees are locked in the primary tree, that is,
       * we acquire a write lock in the primary tree and no locks in the
       * off-page dup tree.  If the del operation is done in an off-page
       * duplicate tree, call the primary cursor's upgrade routine first.
       */
      opd = dbc->internal->opd;
      if (opd == NULL)
            ret = dbc->c_am_del(dbc);
      else
            if ((ret = dbc->c_am_writelock(dbc)) == 0)
                  ret = opd->c_am_del(opd);

done: CDB_LOCKING_DONE(dbp, dbc);

      return (ret);
}

/*
 * __db_c_dup --
 *    Duplicate a cursor
 *
 * PUBLIC: int __db_c_dup __P((DBC *, DBC **, u_int32_t));
 */
int
__db_c_dup(dbc_orig, dbcp, flags)
      DBC *dbc_orig;
      DBC **dbcp;
      u_int32_t flags;
{
      DBC *dbc_n, *dbc_nopd;
      int ret;

      dbc_n = dbc_nopd = NULL;

      /* Allocate a new cursor and initialize it. */
      if ((ret = __db_c_idup(dbc_orig, &dbc_n, flags)) != 0)
            goto err;
      *dbcp = dbc_n;

      /*
       * If the cursor references an off-page duplicate tree, allocate a
       * new cursor for that tree and initialize it.
       */
      if (dbc_orig->internal->opd != NULL) {
            if ((ret =
               __db_c_idup(dbc_orig->internal->opd, &dbc_nopd, flags)) != 0)
                  goto err;
            dbc_n->internal->opd = dbc_nopd;
      }
      return (0);

err:  if (dbc_n != NULL)
            (void)__db_c_close(dbc_n);
      if (dbc_nopd != NULL)
            (void)__db_c_close(dbc_nopd);

      return (ret);
}

/*
 * __db_c_idup --
 *    Internal version of __db_c_dup.
 *
 * PUBLIC: int __db_c_idup __P((DBC *, DBC **, u_int32_t));
 */
int
__db_c_idup(dbc_orig, dbcp, flags)
      DBC *dbc_orig, **dbcp;
      u_int32_t flags;
{
      DB *dbp;
      DBC *dbc_n;
      DBC_INTERNAL *int_n, *int_orig;
      int ret;

      dbp = dbc_orig->dbp;
      dbc_n = *dbcp;

      if ((ret = __db_cursor_int(dbp, dbc_orig->txn, dbc_orig->dbtype,
          dbc_orig->internal->root, F_ISSET(dbc_orig, DBC_OPD),
          dbc_orig->locker, &dbc_n)) != 0)
            return (ret);

      /* If the user wants the cursor positioned, do it here.  */
      if (flags == DB_POSITION) {
            int_n = dbc_n->internal;
            int_orig = dbc_orig->internal;

            dbc_n->flags |= dbc_orig->flags & ~DBC_OWN_LID;

            int_n->indx = int_orig->indx;
            int_n->pgno = int_orig->pgno;
            int_n->root = int_orig->root;
            int_n->lock_mode = int_orig->lock_mode;

            switch (dbc_orig->dbtype) {
            case DB_QUEUE:
                  if ((ret = __qam_c_dup(dbc_orig, dbc_n)) != 0)
                        goto err;
                  break;
            case DB_BTREE:
            case DB_RECNO:
                  if ((ret = __bam_c_dup(dbc_orig, dbc_n)) != 0)
                        goto err;
                  break;
            case DB_HASH:
                  if ((ret = __ham_c_dup(dbc_orig, dbc_n)) != 0)
                        goto err;
                  break;
            case DB_UNKNOWN:
            default:
                  ret = __db_unknown_type(dbp->dbenv,
                      "__db_c_idup", dbc_orig->dbtype);
                  goto err;
            }
      }

      /* Copy the dirty read flag to the new cursor. */
      F_SET(dbc_n, F_ISSET(dbc_orig, DBC_DIRTY_READ));
      F_SET(dbc_n, F_ISSET(dbc_orig, DBC_WRITECURSOR));

      /*
       * If we're in CDB and this isn't an offpage dup cursor, then
       * we need to get a lock for the duplicated cursor.
       */
      if (CDB_LOCKING(dbp->dbenv) && !F_ISSET(dbc_n, DBC_OPD) &&
          (ret = __lock_get(dbp->dbenv, dbc_n->locker, 0,
          &dbc_n->lock_dbt, F_ISSET(dbc_orig, DBC_WRITECURSOR) ?
          DB_LOCK_IWRITE : DB_LOCK_READ, &dbc_n->mylock)) != 0)
            goto err;

      *dbcp = dbc_n;
      return (0);

err:  (void)__db_c_close(dbc_n);
      return (ret);
}

/*
 * __db_c_newopd --
 *    Create a new off-page duplicate cursor.
 *
 * PUBLIC: int __db_c_newopd __P((DBC *, db_pgno_t, DBC *, DBC **));
 */
int
__db_c_newopd(dbc_parent, root, oldopd, dbcp)
      DBC *dbc_parent;
      db_pgno_t root;
      DBC *oldopd;
      DBC **dbcp;
{
      DB *dbp;
      DBC *opd;
      DBTYPE dbtype;
      int ret;

      dbp = dbc_parent->dbp;
      dbtype = (dbp->dup_compare == NULL) ? DB_RECNO : DB_BTREE;

      /*
       * On failure, we want to default to returning the old off-page dup
       * cursor, if any;  our caller can't be left with a dangling pointer
       * to a freed cursor.  On error the only allowable behavior is to
       * close the cursor (and the old OPD cursor it in turn points to), so
       * this should be safe.
       */
      *dbcp = oldopd;

      if ((ret = __db_cursor_int(dbp,
          dbc_parent->txn, dbtype, root, 1, dbc_parent->locker, &opd)) != 0)
            return (ret);

      *dbcp = opd;

      /*
       * Check to see if we already have an off-page dup cursor that we've
       * passed in.  If we do, close it.  It'd be nice to use it again
       * if it's a cursor belonging to the right tree, but if we're doing
       * a cursor-relative operation this might not be safe, so for now
       * we'll take the easy way out and always close and reopen.
       *
       * Note that under no circumstances do we want to close the old
       * cursor without returning a valid new one;  we don't want to
       * leave the main cursor in our caller with a non-NULL pointer
       * to a freed off-page dup cursor.
       */
      if (oldopd != NULL && (ret = __db_c_close(oldopd)) != 0)
            return (ret);

      return (0);
}

/*
 * __db_c_get --
 *    Get using a cursor.
 *
 * PUBLIC: int __db_c_get __P((DBC *, DBT *, DBT *, u_int32_t));
 */
int
__db_c_get(dbc_arg, key, data, flags)
      DBC *dbc_arg;
      DBT *key, *data;
      u_int32_t flags;
{
      DB *dbp;
      DBC *dbc, *dbc_n, *opd;
      DBC_INTERNAL *cp, *cp_n;
      DB_MPOOLFILE *mpf;
      db_pgno_t pgno;
      u_int32_t multi, tmp_dirty, tmp_flags, tmp_rmw;
      u_int8_t type;
      int ret, t_ret;

      /*
       * Cursor Cleanup Note:
       * All of the cursors passed to the underlying access methods by this
       * routine are duplicated cursors.  On return, any referenced pages
       * will be discarded, and, if the cursor is not intended to be used
       * again, the close function will be called.  So, pages/locks that
       * the cursor references do not need to be resolved by the underlying
       * functions.
       */
      dbp = dbc_arg->dbp;
      mpf = dbp->mpf;
      dbc_n = NULL;
      opd = NULL;

      /* Clear OR'd in additional bits so we can check for flag equality. */
      tmp_rmw = LF_ISSET(DB_RMW);
      LF_CLR(DB_RMW);

      tmp_dirty = LF_ISSET(DB_DIRTY_READ);
      LF_CLR(DB_DIRTY_READ);

      multi = LF_ISSET(DB_MULTIPLE|DB_MULTIPLE_KEY);
      LF_CLR(DB_MULTIPLE|DB_MULTIPLE_KEY);

      /*
       * Return a cursor's record number.  It has nothing to do with the
       * cursor get code except that it was put into the interface.
       */
      if (flags == DB_GET_RECNO) {
            if (tmp_rmw)
                  F_SET(dbc_arg, DBC_RMW);
            if (tmp_dirty)
                  F_SET(dbc_arg, DBC_DIRTY_READ);
            ret = __bam_c_rget(dbc_arg, data);
            if (tmp_rmw)
                  F_CLR(dbc_arg, DBC_RMW);
            if (tmp_dirty)
                  F_CLR(dbc_arg, DBC_DIRTY_READ);
            return (ret);
      }

      if (flags == DB_CONSUME || flags == DB_CONSUME_WAIT)
            CDB_LOCKING_INIT(dbp, dbc_arg);

      /*
       * If we have an off-page duplicates cursor, and the operation applies
       * to it, perform the operation.  Duplicate the cursor and call the
       * underlying function.
       *
       * Off-page duplicate trees are locked in the primary tree, that is,
       * we acquire a write lock in the primary tree and no locks in the
       * off-page dup tree.  If the DB_RMW flag was specified and the get
       * operation is done in an off-page duplicate tree, call the primary
       * cursor's upgrade routine first.
       */
      cp = dbc_arg->internal;
      if (cp->opd != NULL &&
          (flags == DB_CURRENT || flags == DB_GET_BOTHC ||
          flags == DB_NEXT || flags == DB_NEXT_DUP || flags == DB_PREV)) {
            if (tmp_rmw && (ret = dbc_arg->c_am_writelock(dbc_arg)) != 0)
                  return (ret);
            if ((ret = __db_c_idup(cp->opd, &opd, DB_POSITION)) != 0)
                  return (ret);

            switch (ret =
                opd->c_am_get(opd, key, data, flags, NULL)) {
            case 0:
                  goto done;
            case DB_NOTFOUND:
                  /*
                   * Translate DB_NOTFOUND failures for the DB_NEXT and
                   * DB_PREV operations into a subsequent operation on
                   * the parent cursor.
                   */
                  if (flags == DB_NEXT || flags == DB_PREV) {
                        if ((ret = __db_c_close(opd)) != 0)
                              goto err;
                        opd = NULL;
                        break;
                  }
                  goto err;
            default:
                  goto err;
            }
      }

      /*
       * Perform an operation on the main cursor.  Duplicate the cursor,
       * upgrade the lock as required, and call the underlying function.
       */
      switch (flags) {
      case DB_CURRENT:
      case DB_GET_BOTHC:
      case DB_NEXT:
      case DB_NEXT_DUP:
      case DB_NEXT_NODUP:
      case DB_PREV:
      case DB_PREV_NODUP:
            tmp_flags = DB_POSITION;
            break;
      default:
            tmp_flags = 0;
            break;
      }

      if (tmp_dirty)
            F_SET(dbc_arg, DBC_DIRTY_READ);

      /*
       * If this cursor is going to be closed immediately, we don't
       * need to take precautions to clean it up on error.
       */
      if (F_ISSET(dbc_arg, DBC_TRANSIENT))
            dbc_n = dbc_arg;
      else {
            ret = __db_c_idup(dbc_arg, &dbc_n, tmp_flags);
            if (tmp_dirty)
                  F_CLR(dbc_arg, DBC_DIRTY_READ);

            if (ret != 0)
                  goto err;
            COPY_RET_MEM(dbc_arg, dbc_n);
      }

      if (tmp_rmw)
            F_SET(dbc_n, DBC_RMW);

      switch (multi) {
      case DB_MULTIPLE:
            F_SET(dbc_n, DBC_MULTIPLE);
            break;
      case DB_MULTIPLE_KEY:
            F_SET(dbc_n, DBC_MULTIPLE_KEY);
            break;
      case DB_MULTIPLE | DB_MULTIPLE_KEY:
            F_SET(dbc_n, DBC_MULTIPLE|DBC_MULTIPLE_KEY);
            break;
      case 0:
      default:
            break;
      }

      pgno = PGNO_INVALID;
      ret = dbc_n->c_am_get(dbc_n, key, data, flags, &pgno);
      if (tmp_rmw)
            F_CLR(dbc_n, DBC_RMW);
      if (tmp_dirty)
            F_CLR(dbc_arg, DBC_DIRTY_READ);
      F_CLR(dbc_n, DBC_MULTIPLE|DBC_MULTIPLE_KEY);
      if (ret != 0)
            goto err;

      cp_n = dbc_n->internal;

      /*
       * We may be referencing a new off-page duplicates tree.  Acquire
       * a new cursor and call the underlying function.
       */
      if (pgno != PGNO_INVALID) {
            if ((ret = __db_c_newopd(dbc_arg,
                pgno, cp_n->opd, &cp_n->opd)) != 0)
                  goto err;

            switch (flags) {
            case DB_FIRST:
            case DB_NEXT:
            case DB_NEXT_NODUP:
            case DB_SET:
            case DB_SET_RECNO:
            case DB_SET_RANGE:
                  tmp_flags = DB_FIRST;
                  break;
            case DB_LAST:
            case DB_PREV:
            case DB_PREV_NODUP:
                  tmp_flags = DB_LAST;
                  break;
            case DB_GET_BOTH:
            case DB_GET_BOTHC:
            case DB_GET_BOTH_RANGE:
                  tmp_flags = flags;
                  break;
            default:
                  ret =
                      __db_unknown_flag(dbp->dbenv, "__db_c_get", flags);
                  goto err;
            }
            if ((ret = cp_n->opd->c_am_get(
                cp_n->opd, key, data, tmp_flags, NULL)) != 0)
                  goto err;
      }

done: /*
       * Return a key/data item.  The only exception is that we don't return
       * a key if the user already gave us one, that is, if the DB_SET flag
       * was set.  The DB_SET flag is necessary.  In a Btree, the user's key
       * doesn't have to be the same as the key stored the tree, depending on
       * the magic performed by the comparison function.  As we may not have
       * done any key-oriented operation here, the page reference may not be
       * valid.  Fill it in as necessary.  We don't have to worry about any
       * locks, the cursor must already be holding appropriate locks.
       *
       * XXX
       * If not a Btree and DB_SET_RANGE is set, we shouldn't return a key
       * either, should we?
       */
      cp_n = dbc_n == NULL ? dbc_arg->internal : dbc_n->internal;
      if (!F_ISSET(key, DB_DBT_ISSET)) {
            if (cp_n->page == NULL && (ret =
                __memp_fget(mpf, &cp_n->pgno, 0, &cp_n->page)) != 0)
                  goto err;

            if ((ret = __db_ret(dbp, cp_n->page, cp_n->indx,
                key, &dbc_arg->rkey->data, &dbc_arg->rkey->ulen)) != 0)
                  goto err;
      }
      if (multi != 0) {
            /*
             * Even if fetching from the OPD cursor we need a duplicate
             * primary cursor if we are going after multiple keys.
             */
            if (dbc_n == NULL) {
                  /*
                   * Non-"_KEY" DB_MULTIPLE doesn't move the main cursor,
                   * so it's safe to just use dbc_arg, unless dbc_arg
                   * has an open OPD cursor whose state might need to
                   * be preserved.
                   */
                  if ((!(multi & DB_MULTIPLE_KEY) &&
                      dbc_arg->internal->opd == NULL) ||
                      F_ISSET(dbc_arg, DBC_TRANSIENT))
                        dbc_n = dbc_arg;
                  else {
                        if ((ret = __db_c_idup(dbc_arg,
                            &dbc_n, DB_POSITION)) != 0)
                              goto err;
                        if ((ret = dbc_n->c_am_get(dbc_n,
                            key, data, DB_CURRENT, &pgno)) != 0)
                              goto err;
                  }
                  cp_n = dbc_n->internal;
            }

            /*
             * If opd is set then we dupped the opd that we came in with.
             * When we return we may have a new opd if we went to another
             * key.
             */
            if (opd != NULL) {
                  DB_ASSERT(cp_n->opd == NULL);
                  cp_n->opd = opd;
                  opd = NULL;
            }

            /*
             * Bulk get doesn't use __db_retcopy, so data.size won't
             * get set up unless there is an error.  Assume success
             * here.  This is the only call to c_am_bulk, and it avoids
             * setting it exactly the same everywhere.  If we have an
             * ENOMEM error, it'll get overwritten with the needed value.
             */
            data->size = data->ulen;
            ret = dbc_n->c_am_bulk(dbc_n, data, flags | multi);
      } else if (!F_ISSET(data, DB_DBT_ISSET)) {
            dbc = opd != NULL ? opd : cp_n->opd != NULL ? cp_n->opd : dbc_n;
            type = TYPE(dbc->internal->page);
            ret = __db_ret(dbp, dbc->internal->page, dbc->internal->indx +
                (type == P_LBTREE || type == P_HASH ? O_INDX : 0),
                data, &dbc_arg->rdata->data, &dbc_arg->rdata->ulen);
      }

err:  /* Don't pass DB_DBT_ISSET back to application level, error or no. */
      F_CLR(key, DB_DBT_ISSET);
      F_CLR(data, DB_DBT_ISSET);

      /* Cleanup and cursor resolution. */
      if (opd != NULL) {
            if ((t_ret = __db_c_cleanup(
                dbc_arg->internal->opd, opd, ret)) != 0 && ret == 0)
                  ret = t_ret;

      }

      if ((t_ret = __db_c_cleanup(dbc_arg, dbc_n, ret)) != 0 && ret == 0)
            ret = t_ret;

      if (flags == DB_CONSUME || flags == DB_CONSUME_WAIT)
            CDB_LOCKING_DONE(dbp, dbc_arg);
      return (ret);
}

/*
 * __db_c_put --
 *    Put using a cursor.
 *
 * PUBLIC: int __db_c_put __P((DBC *, DBT *, DBT *, u_int32_t));
 */
int
__db_c_put(dbc_arg, key, data, flags)
      DBC *dbc_arg;
      DBT *key, *data;
      u_int32_t flags;
{
      DB_ENV *dbenv;
      DB *dbp, *sdbp;
      DBC *dbc_n, *oldopd, *opd, *sdbc, *pdbc;
      DBT olddata, oldpkey, oldskey, newdata, pkey, skey, temppkey, tempskey;
      db_pgno_t pgno;
      int cmp, have_oldrec, ispartial, nodel, re_pad, ret, rmw, t_ret;
      u_int32_t re_len, size, tmp_flags;

      /*
       * Cursor Cleanup Note:
       * All of the cursors passed to the underlying access methods by this
       * routine are duplicated cursors.  On return, any referenced pages
       * will be discarded, and, if the cursor is not intended to be used
       * again, the close function will be called.  So, pages/locks that
       * the cursor references do not need to be resolved by the underlying
       * functions.
       */
      dbp = dbc_arg->dbp;
      dbenv = dbp->dbenv;
      sdbp = NULL;
      pdbc = dbc_n = NULL;
      memset(&newdata, 0, sizeof(DBT));
      ret = 0;

      /*
       * We do multiple cursor operations in some cases and subsequently
       * access the data DBT information.  Set DB_DBT_MALLOC so we don't risk
       * modification of the data between our uses of it.
       */
      memset(&olddata, 0, sizeof(DBT));
      F_SET(&olddata, DB_DBT_MALLOC);

      /*
       * Putting to secondary indices is forbidden;  when we need
       * to internally update one, we'll call this with a private
       * synonym for DB_KEYLAST, DB_UPDATE_SECONDARY, which does
       * the right thing but won't return an error from cputchk().
       */
      if (flags == DB_UPDATE_SECONDARY)
            flags = DB_KEYLAST;

      CDB_LOCKING_INIT(dbp, dbc_arg);

      /*
       * Check to see if we are a primary and have secondary indices.
       * If we are not, we save ourselves a good bit of trouble and
       * just skip to the "normal" put.
       */
      if (LIST_FIRST(&dbp->s_secondaries) == NULL)
            goto skip_s_update;

      /*
       * We have at least one secondary which we may need to update.
       *
       * There is a rather vile locking issue here.  Secondary gets
       * will always involve acquiring a read lock in the secondary,
       * then acquiring a read lock in the primary.  Ideally, we
       * would likewise perform puts by updating all the secondaries
       * first, then doing the actual put in the primary, to avoid
       * deadlock (since having multiple threads doing secondary
       * gets and puts simultaneously is probably a common case).
       *
       * However, if this put is a put-overwrite--and we have no way to
       * tell in advance whether it will be--we may need to delete
       * an outdated secondary key.  In order to find that old
       * secondary key, we need to get the record we're overwriting,
       * before we overwrite it.
       *
       * (XXX: It would be nice to avoid this extra get, and have the
       * underlying put routines somehow pass us the old record
       * since they need to traverse the tree anyway.  I'm saving
       * this optimization for later, as it's a lot of work, and it
       * would be hard to fit into this locking paradigm anyway.)
       *
       * The simple thing to do would be to go get the old record before
       * we do anything else.  Unfortunately, though, doing so would
       * violate our "secondary, then primary" lock acquisition
       * ordering--even in the common case where no old primary record
       * exists, we'll still acquire and keep a lock on the page where
       * we're about to do the primary insert.
       *
       * To get around this, we do the following gyrations, which
       * hopefully solve this problem in the common case:
       *
       * 1) If this is a c_put(DB_CURRENT), go ahead and get the
       *    old record.  We already hold the lock on this page in
       *    the primary, so no harm done, and we'll need the primary
       *    key (which we weren't passed in this case) to do any
       *    secondary puts anyway.
       *
       * 2) If we're doing a partial put, we need to perform the
       *    get on the primary key right away, since we don't have
       *    the whole datum that the secondary key is based on.
       *    We may also need to pad out the record if the primary
       *    has a fixed record length.
       *
       * 3) Loop through the secondary indices, putting into each a
       *    new secondary key that corresponds to the new record.
       *
       * 4) If we haven't done so in (1) or (2), get the old primary
       *    key/data pair.  If one does not exist--the common case--we're
       *    done with secondary indices, and can go straight on to the
       *    primary put.
       *
       * 5) If we do have an old primary key/data pair, however, we need
       *    to loop through all the secondaries a second time and delete
       *    the old secondary in each.
       */
      memset(&pkey, 0, sizeof(DBT));
      have_oldrec = nodel = 0;

      /*
       * Primary indices can't have duplicates, so only DB_CURRENT,
       * DB_KEYFIRST, and DB_KEYLAST make any sense.  Other flags
       * should have been caught by the checking routine, but
       * add a sprinkling of paranoia.
       */
      DB_ASSERT(flags == DB_CURRENT ||
          flags == DB_KEYFIRST || flags == DB_KEYLAST);

      /*
       * We'll want to use DB_RMW in a few places, but it's only legal
       * when locking is on.
       */
      rmw = STD_LOCKING(dbc_arg) ? DB_RMW : 0;

      /*
       * Set pkey so we can use &pkey everywhere instead of key.
       * If DB_CURRENT is set and there is a key at the current
       * location, pkey will be overwritten before it's used.
       */
      pkey.data = key->data;
      pkey.size = key->size;

      if (flags == DB_CURRENT) {          /* Step 1. */
            /*
             * This is safe to do on the cursor we already have;
             * error or no, it won't move.
             *
             * We use DB_RMW for all of these gets because we'll be
             * writing soon enough in the "normal" put code.  In
             * transactional databases we'll hold those write locks
             * even if we close the cursor we're reading with.
             */
            ret = __db_c_get(dbc_arg, &pkey, &olddata, rmw | DB_CURRENT);
            if (ret == DB_KEYEMPTY) {
                  nodel = 1;   /*
                                * We know we don't need a delete
                                * in the secondary.
                                */
                  have_oldrec = 1; /* We've looked for the old record. */
                  ret = 0;
            } else if (ret != 0)
                  goto err;
            else
                  have_oldrec = 1;
      }

      /*
       * Check for partial puts (step 2).
       */
      if (F_ISSET(data, DB_DBT_PARTIAL)) {
            if (!have_oldrec && !nodel) {
                  /*
                   * We're going to have to search the tree for the
                   * specified key.  Dup a cursor (so we have the same
                   * locking info) and do a c_get.
                   */
                  if ((ret = __db_c_idup(dbc_arg, &pdbc, 0)) != 0)
                        goto err;

                  /* We should have gotten DB_CURRENT in step 1. */
                  DB_ASSERT(flags != DB_CURRENT);

                  ret = __db_c_get(pdbc, &pkey, &olddata, rmw | DB_SET);
                  if (ret == DB_KEYEMPTY || ret == DB_NOTFOUND) {
                        nodel = 1;
                        ret = 0;
                  }
                  if ((t_ret = __db_c_close(pdbc)) != 0)
                        ret = t_ret;
                  if (ret != 0)
                        goto err;

                  have_oldrec = 1;
            }

            /*
             * Now build the new datum from olddata and the partial
             * data we were given.
             */
            if ((ret =
                __db_buildpartial(dbp, &olddata, data, &newdata)) != 0)
                  goto err;
            ispartial = 1;
      } else
            ispartial = 0;

      /*
       * Handle fixed-length records.  If the primary database has
       * fixed-length records, we need to pad out the datum before
       * we pass it into the callback function;  we always index the
       * "real" record.
       */
      if ((dbp->type == DB_RECNO && F_ISSET(dbp, DB_AM_FIXEDLEN)) ||
          (dbp->type == DB_QUEUE)) {
            if (dbp->type == DB_QUEUE) {
                  re_len = ((QUEUE *)dbp->q_internal)->re_len;
                  re_pad = ((QUEUE *)dbp->q_internal)->re_pad;
            } else {
                  re_len = ((BTREE *)dbp->bt_internal)->re_len;
                  re_pad = ((BTREE *)dbp->bt_internal)->re_pad;
            }

            size = ispartial ? newdata.size : data->size;
            if (size > re_len) {
                  ret = __db_rec_toobig(dbenv, size, re_len);
                  goto err;
            } else if (size < re_len) {
                  /*
                   * If we're not doing a partial put, copy
                   * data->data into newdata.data, then pad out
                   * newdata.data.
                   *
                   * If we're doing a partial put, the data
                   * we want are already in newdata.data;  we
                   * just need to pad.
                   *
                   * Either way, realloc is safe.
                   */
                  if ((ret =
                      __os_realloc(dbenv, re_len, &newdata.data)) != 0)
                        goto err;
                  if (!ispartial)
                        memcpy(newdata.data, data->data, size);
                  memset((u_int8_t *)newdata.data + size, re_pad,
                      re_len - size);
                  newdata.size = re_len;
                  ispartial = 1;
            }
      }

      /*
       * Loop through the secondaries.  (Step 3.)
       *
       * Note that __db_s_first and __db_s_next will take care of
       * thread-locking and refcounting issues.
       */
      for (sdbp = __db_s_first(dbp);
          sdbp != NULL && ret == 0; ret = __db_s_next(&sdbp)) {
            /*
             * Call the callback for this secondary, to get the
             * appropriate secondary key.
             */
            memset(&skey, 0, sizeof(DBT));
            if ((ret = sdbp->s_callback(sdbp,
                &pkey, ispartial ? &newdata : data, &skey)) != 0) {
                  if (ret == DB_DONOTINDEX)
                        /*
                         * The callback returned a null value--don't
                         * put this key in the secondary.  Just
                         * move on to the next one--we'll handle
                         * any necessary deletes in step 5.
                         */
                        continue;
                  else
                        goto err;
            }

            /*
             * Open a cursor in this secondary.
             *
             * Use the same locker ID as our primary cursor, so that
             * we're guaranteed that the locks don't conflict (e.g. in CDB
             * or if we're subdatabases that share and want to lock a
             * metadata page).
             */
            if ((ret = __db_cursor_int(sdbp, dbc_arg->txn, sdbp->type,
                PGNO_INVALID, 0, dbc_arg->locker, &sdbc)) != 0)
                  goto err;

            /*
             * If we're in CDB, updates will fail since the new cursor
             * isn't a writer.  However, we hold the WRITE lock in the
             * primary and will for as long as our new cursor lasts,
             * and the primary and secondary share a lock file ID,
             * so it's safe to consider this a WRITER.  The close
             * routine won't try to put anything because we don't
             * really have a lock.
             */
            if (CDB_LOCKING(dbenv)) {
                  DB_ASSERT(sdbc->mylock.off == LOCK_INVALID);
                  F_SET(sdbc, DBC_WRITER);
            }

            /*
             * There are three cases here--
             * 1) The secondary supports sorted duplicates.
             *    If we attempt to put a secondary/primary pair
             *    that already exists, that's a duplicate duplicate,
             *    and c_put will return DB_KEYEXIST (see __db_duperr).
             *    This will leave us with exactly one copy of the
             *    secondary/primary pair, and this is just right--we'll
             *    avoid deleting it later, as the old and new secondaries
             *    will match (since the old secondary is the dup dup
             *    that's already there).
             * 2) The secondary supports duplicates, but they're not
             *    sorted.  We need to avoid putting a duplicate
             *    duplicate, because the matching old and new secondaries
             *    will prevent us from deleting anything and we'll
             *    wind up with two secondary records that point to the
             *    same primary key.  Do a c_get(DB_GET_BOTH);  only
             *    do the put if the secondary doesn't exist.
             * 3) The secondary doesn't support duplicates at all.
             *    In this case, secondary keys must be unique;  if
             *    another primary key already exists for this
             *    secondary key, we have to either overwrite it or
             *    not put this one, and in either case we've
             *    corrupted the secondary index.  Do a c_get(DB_SET).
             *    If the secondary/primary pair already exists, do
             *    nothing;  if the secondary exists with a different
             *    primary, return an error;  and if the secondary
             *    does not exist, put it.
             */
            if (!F_ISSET(sdbp, DB_AM_DUP)) {
                  /* Case 3. */
                  memset(&oldpkey, 0, sizeof(DBT));
                  F_SET(&oldpkey, DB_DBT_MALLOC);
                  ret = __db_c_get(sdbc,
                      &skey, &oldpkey, rmw | DB_SET);
                  if (ret == 0) {
                        cmp = __bam_defcmp(sdbp, &oldpkey, &pkey);
                        __os_ufree(dbenv, oldpkey.data);
                        if (cmp != 0) {
                              __db_err(dbenv, "%s%s",
                      "Put results in a non-unique secondary key in an ",
                      "index not configured to support duplicates");
                              ret = EINVAL;
                              goto skipput;
                        }
                  } else if (ret != DB_NOTFOUND && ret != DB_KEYEMPTY)
                        goto skipput;
            } else if (!F_ISSET(sdbp, DB_AM_DUPSORT)) {
                  /* Case 2. */
                  memset(&tempskey, 0, sizeof (DBT));
                  tempskey.data = skey.data;
                  tempskey.size = skey.size;
                  memset(&temppkey, 0, sizeof (DBT));
                  temppkey.data = pkey.data;
                  temppkey.size = pkey.size;
                  ret = __db_c_get(sdbc, &tempskey, &temppkey,
                      rmw | DB_GET_BOTH);
                  if (ret != DB_NOTFOUND && ret != DB_KEYEMPTY)
                        goto skipput;
            }

            ret = __db_c_put(sdbc, &skey, &pkey, DB_UPDATE_SECONDARY);

            /*
             * We don't know yet whether this was a put-overwrite that
             * in fact changed nothing.  If it was, we may get DB_KEYEXIST.
             * This is not an error.
             */
            if (ret == DB_KEYEXIST)
                  ret = 0;

skipput:    FREE_IF_NEEDED(sdbp, &skey)

            if ((t_ret = __db_c_close(sdbc)) != 0 && ret == 0)
                  ret = t_ret;

            if (ret != 0)
                  goto err;
      }
      if (ret != 0)
            goto err;

      /* If still necessary, go get the old primary key/data.  (Step 4.) */
      if (!have_oldrec) {
            /* See the comments in step 2.  This is real familiar. */
            if ((ret = __db_c_idup(dbc_arg, &pdbc, 0)) != 0)
                  goto err;
            DB_ASSERT(flags != DB_CURRENT);
            pkey.data = key->data;
            pkey.size = key->size;
            ret = __db_c_get(pdbc, &pkey, &olddata, rmw | DB_SET);
            if (ret == DB_KEYEMPTY || ret == DB_NOTFOUND) {
                  nodel = 1;
                  ret = 0;
            }
            if ((t_ret = __db_c_close(pdbc)) != 0 && ret == 0)
                  ret = t_ret;
            if (ret != 0)
                  goto err;
            have_oldrec = 1;
      }

      /*
       * If we don't follow this goto, we do in fact have an old record
       * we may need to go delete.  (Step 5).
       */
      if (nodel)
            goto skip_s_update;

      for (sdbp = __db_s_first(dbp);
          sdbp != NULL && ret == 0; ret = __db_s_next(&sdbp)) {
            /*
             * Call the callback for this secondary to get the
             * old secondary key.
             */
            memset(&oldskey, 0, sizeof(DBT));
            if ((ret = sdbp->s_callback(sdbp,
                &pkey, &olddata, &oldskey)) != 0) {
                  if (ret == DB_DONOTINDEX)
                        /*
                         * The callback returned a null value--there's
                         * nothing to delete.  Go on to the next
                         * secondary.
                         */
                        continue;
                  else
                        goto err;
            }
            memset(&skey, 0, sizeof(DBT));
            if ((ret = sdbp->s_callback(sdbp,
                &pkey, ispartial ? &newdata : data, &skey)) != 0 &&
                ret != DB_DONOTINDEX)
                  goto err;

            /*
             * If there is no new secondary key, or if the old secondary
             * key is different from the new secondary key, then
             * we need to delete the old one.
             *
             * Note that bt_compare is (and must be) set no matter
             * what access method we're in.
             */
            sdbc = NULL;
            if (ret == DB_DONOTINDEX ||
                ((BTREE *)sdbp->bt_internal)->bt_compare(sdbp,
                &oldskey, &skey) != 0) {
                  if ((ret = __db_cursor_int(
                      sdbp, dbc_arg->txn, sdbp->type,
                      PGNO_INVALID, 0, dbc_arg->locker, &sdbc)) != 0)
                        goto err;
                  if (CDB_LOCKING(dbenv)) {
                        DB_ASSERT(sdbc->mylock.off == LOCK_INVALID);
                        F_SET(sdbc, DBC_WRITER);
                  }

                  /*
                   * Don't let c_get(DB_GET_BOTH) stomp on
                   * our data.  Use a temp DBT instead.
                   */
                  memset(&tempskey, 0, sizeof(DBT));
                  tempskey.data = oldskey.data;
                  tempskey.size = oldskey.size;
                  memset(&temppkey, 0, sizeof(DBT));
                  temppkey.data = pkey.data;
                  temppkey.size = pkey.size;
                  if ((ret = __db_c_get(sdbc,
                      &tempskey, &temppkey, rmw | DB_GET_BOTH)) == 0)
                        ret = __db_c_del(sdbc, DB_UPDATE_SECONDARY);
                  else if (ret == DB_NOTFOUND)
                        ret = __db_secondary_corrupt(dbp);
            }

            FREE_IF_NEEDED(sdbp, &skey);
            FREE_IF_NEEDED(sdbp, &oldskey);
            if (sdbc != NULL && (t_ret = __db_c_close(sdbc)) != 0 &&
                ret == 0)
                  ret = t_ret;
            if (ret != 0)
                  goto err;
      }

      /* Secondary index updates are now done.  On to the "real" stuff. */

skip_s_update:
      /*
       * If we have an off-page duplicates cursor, and the operation applies
       * to it, perform the operation.  Duplicate the cursor and call the
       * underlying function.
       *
       * Off-page duplicate trees are locked in the primary tree, that is,
       * we acquire a write lock in the primary tree and no locks in the
       * off-page dup tree.  If the put operation is done in an off-page
       * duplicate tree, call the primary cursor's upgrade routine first.
       */
      if (dbc_arg->internal->opd != NULL &&
          (flags == DB_AFTER || flags == DB_BEFORE || flags == DB_CURRENT)) {
            /*
             * A special case for hash off-page duplicates.  Hash doesn't
             * support (and is documented not to support) put operations
             * relative to a cursor which references an already deleted
             * item.  For consistency, apply the same criteria to off-page
             * duplicates as well.
             */
            if (dbc_arg->dbtype == DB_HASH && F_ISSET(
                ((BTREE_CURSOR *)(dbc_arg->internal->opd->internal)),
                C_DELETED)) {
                  ret = DB_NOTFOUND;
                  goto err;
            }

            if ((ret = dbc_arg->c_am_writelock(dbc_arg)) != 0)
                  return (ret);
            if ((ret = __db_c_dup(dbc_arg, &dbc_n, DB_POSITION)) != 0)
                  goto err;
            opd = dbc_n->internal->opd;
            if ((ret = opd->c_am_put(
                opd, key, data, flags, NULL)) != 0)
                  goto err;
            goto done;
      }

      /*
       * Perform an operation on the main cursor.  Duplicate the cursor,
       * and call the underlying function.
       *
       * XXX: MARGO
       *
      tmp_flags = flags == DB_AFTER ||
          flags == DB_BEFORE || flags == DB_CURRENT ? DB_POSITION : 0;
       */
      tmp_flags = DB_POSITION;

      /*
       * If this cursor is going to be closed immediately, we don't
       * need to take precautions to clean it up on error.
       */
      if (F_ISSET(dbc_arg, DBC_TRANSIENT))
            dbc_n = dbc_arg;
      else if ((ret = __db_c_idup(dbc_arg, &dbc_n, tmp_flags)) != 0)
            goto err;

      pgno = PGNO_INVALID;
      if ((ret = dbc_n->c_am_put(dbc_n, key, data, flags, &pgno)) != 0)
            goto err;

      /*
       * We may be referencing a new off-page duplicates tree.  Acquire
       * a new cursor and call the underlying function.
       */
      if (pgno != PGNO_INVALID) {
            oldopd = dbc_n->internal->opd;
            if ((ret = __db_c_newopd(dbc_arg, pgno, oldopd, &opd)) != 0) {
                  dbc_n->internal->opd = opd;
                  goto err;
            }

            dbc_n->internal->opd = opd;

            if ((ret = opd->c_am_put(
                opd, key, data, flags, NULL)) != 0)
                  goto err;
      }

done:
err:  /* Cleanup and cursor resolution. */
      if ((t_ret = __db_c_cleanup(dbc_arg, dbc_n, ret)) != 0 && ret == 0)
            ret = t_ret;

      /* If newdata or olddata were used, free their buffers. */
      if (newdata.data != NULL)
            __os_free(dbenv, newdata.data);
      if (olddata.data != NULL)
            __os_ufree(dbenv, olddata.data);

      CDB_LOCKING_DONE(dbp, dbc_arg);

      if (sdbp != NULL && (t_ret = __db_s_done(sdbp)) != 0 && ret == 0)
            ret = t_ret;

      return (ret);
}

/*
 * __db_duperr()
 *    Error message: we don't currently support sorted duplicate duplicates.
 * PUBLIC: int __db_duperr __P((DB *, u_int32_t));
 */
int
__db_duperr(dbp, flags)
      DB *dbp;
      u_int32_t flags;
{

      /*
       * If we run into this error while updating a secondary index,
       * don't yell--there's no clean way to pass DB_NODUPDATA in along
       * with DB_UPDATE_SECONDARY, but we may run into this problem
       * in a normal, non-error course of events.
       *
       * !!!
       * If and when we ever permit duplicate duplicates in sorted-dup
       * databases, we need to either change the secondary index code
       * to check for dup dups, or we need to maintain the implicit
       * "DB_NODUPDATA" behavior for databases with DB_AM_SECONDARY set.
       */
      if (flags != DB_NODUPDATA && !F_ISSET(dbp, DB_AM_SECONDARY))
            __db_err(dbp->dbenv,
                "Duplicate data items are not supported with sorted data");
      return (DB_KEYEXIST);
}

/*
 * __db_c_cleanup --
 *    Clean up duplicate cursors.
 */
static int
__db_c_cleanup(dbc, dbc_n, failed)
      DBC *dbc, *dbc_n;
      int failed;
{
      DB *dbp;
      DBC *opd;
      DBC_INTERNAL *internal;
      DB_MPOOLFILE *mpf;
      int ret, t_ret;

      dbp = dbc->dbp;
      mpf = dbp->mpf;
      internal = dbc->internal;
      ret = 0;

      /* Discard any pages we're holding. */
      if (internal->page != NULL) {
            if ((t_ret =
                __memp_fput(mpf, internal->page, 0)) != 0 && ret == 0)
                  ret = t_ret;
            internal->page = NULL;
      }
      opd = internal->opd;
      if (opd != NULL && opd->internal->page != NULL) {
            if ((t_ret =
                __memp_fput(mpf, opd->internal->page, 0)) != 0 && ret == 0)
                  ret = t_ret;
            opd->internal->page = NULL;
      }

      /*
       * If dbc_n is NULL, there's no internal cursor swapping to be done
       * and no dbc_n to close--we probably did the entire operation on an
       * offpage duplicate cursor.  Just return.
       *
       * If dbc and dbc_n are the same, we're either inside a DB->{put/get}
       * operation, and as an optimization we performed the operation on
       * the main cursor rather than on a duplicated one, or we're in a
       * bulk get that can't have moved the cursor (DB_MULTIPLE with the
       * initial c_get operation on an off-page dup cursor).  Just
       * return--either we know we didn't move the cursor, or we're going
       * to close it before we return to application code, so we're sure
       * not to visibly violate the "cursor stays put on error" rule.
       */
      if (dbc_n == NULL || dbc == dbc_n)
            return (ret);

      if (dbc_n->internal->page != NULL) {
            if ((t_ret = __memp_fput(
                mpf, dbc_n->internal->page, 0)) != 0 && ret == 0)
                  ret = t_ret;
            dbc_n->internal->page = NULL;
      }
      opd = dbc_n->internal->opd;
      if (opd != NULL && opd->internal->page != NULL) {
            if ((t_ret =
                __memp_fput(mpf, opd->internal->page, 0)) != 0 && ret == 0)
                  ret = t_ret;
            opd->internal->page = NULL;
      }

      /*
       * If we didn't fail before entering this routine or just now when
       * freeing pages, swap the interesting contents of the old and new
       * cursors.
       */
      if (!failed && ret == 0) {
            dbc->internal = dbc_n->internal;
            dbc_n->internal = internal;
      }

      /*
       * Close the cursor we don't care about anymore.  The close can fail,
       * but we only expect DB_LOCK_DEADLOCK failures.  This violates our
       * "the cursor is unchanged on error" semantics, but since all you can
       * do with a DB_LOCK_DEADLOCK failure is close the cursor, I believe
       * that's OK.
       *
       * XXX
       * There's no way to recover from failure to close the old cursor.
       * All we can do is move to the new position and return an error.
       *
       * XXX
       * We might want to consider adding a flag to the cursor, so that any
       * subsequent operations other than close just return an error?
       */
      if ((t_ret = __db_c_close(dbc_n)) != 0 && ret == 0)
            ret = t_ret;

      return (ret);
}

/*
 * __db_c_secondary_get_pp --
 *    This wrapper function for DBC->c_pget() is the DBC->c_get() function
 *    for a secondary index cursor.
 *
 * PUBLIC: int __db_c_secondary_get_pp __P((DBC *, DBT *, DBT *, u_int32_t));
 */
int
__db_c_secondary_get_pp(dbc, skey, data, flags)
      DBC *dbc;
      DBT *skey, *data;
      u_int32_t flags;
{

      DB_ASSERT(F_ISSET(dbc->dbp, DB_AM_SECONDARY));
      return (__db_c_pget_pp(dbc, skey, NULL, data, flags));
}

/*
 * __db_c_pget --
 *    Get a primary key/data pair through a secondary index.
 *
 * PUBLIC: int __db_c_pget __P((DBC *, DBT *, DBT *, DBT *, u_int32_t));
 */
int
__db_c_pget(dbc, skey, pkey, data, flags)
      DBC *dbc;
      DBT *skey, *pkey, *data;
      u_int32_t flags;
{
      DB *pdbp, *sdbp;
      DBC *pdbc;
      DBT *save_rdata, nullpkey;
      u_int32_t save_pkey_flags;
      int pkeymalloc, ret, t_ret;

      sdbp = dbc->dbp;
      pdbp = sdbp->s_primary;
      pkeymalloc = t_ret = 0;

      /*
       * The challenging part of this function is getting the behavior
       * right for all the various permutations of DBT flags.  The
       * next several blocks handle the various cases we need to
       * deal with specially.
       */

      /*
       * We may be called with a NULL pkey argument, if we've been
       * wrapped by a 2-DBT get call.  If so, we need to use our
       * own DBT.
       */
      if (pkey == NULL) {
            memset(&nullpkey, 0, sizeof(DBT));
            pkey = &nullpkey;
      }

      /*
       * DB_GET_RECNO is a special case, because we're interested not in
       * the primary key/data pair, but rather in the primary's record
       * number.
       */
      if ((flags & DB_OPFLAGS_MASK) == DB_GET_RECNO)
            return (__db_c_pget_recno(dbc, pkey, data, flags));

      /*
       * If the DBTs we've been passed don't have any of the
       * user-specified memory management flags set, we want to make sure
       * we return values using the DBTs dbc->rskey, dbc->rkey, and
       * dbc->rdata, respectively.
       *
       * There are two tricky aspects to this:  first, we need to pass
       * skey and pkey *in* to the initial c_get on the secondary key,
       * since either or both may be looked at by it (depending on the
       * get flag).  Second, we must not use a normal DB->get call
       * on the secondary, even though that's what we want to accomplish,
       * because the DB handle may be free-threaded.  Instead,
       * we open a cursor, then take steps to ensure that we actually use
       * the rkey/rdata from the *secondary* cursor.
       *
       * We accomplish all this by passing in the DBTs we started out
       * with to the c_get, but having swapped the contents of rskey and
       * rkey, respectively, into rkey and rdata;  __db_ret will treat
       * them like the normal key/data pair in a c_get call, and will
       * realloc them as need be (this is "step 1").  Then, for "step 2",
       * we swap back rskey/rkey/rdata to normal, and do a get on the primary
       * with the secondary dbc appointed as the owner of the returned-data
       * memory.
       *
       * Note that in step 2, we copy the flags field in case we need to
       * pass down a DB_DBT_PARTIAL or other flag that is compatible with
       * letting DB do the memory management.
       */
      /* Step 1. */
      save_rdata = dbc->rdata;
      dbc->rdata = dbc->rkey;
      dbc->rkey = dbc->rskey;

      /*
       * It is correct, though slightly sick, to attempt a partial get
       * of a primary key.  However, if we do so here, we'll never find the
       * primary record;  clear the DB_DBT_PARTIAL field of pkey just
       * for the duration of the next call.
       */
      save_pkey_flags = pkey->flags;
      F_CLR(pkey, DB_DBT_PARTIAL);

      /*
       * Now we can go ahead with the meat of this call.  First, get the
       * primary key from the secondary index.  (What exactly we get depends
       * on the flags, but the underlying cursor get will take care of the
       * dirty work.)
       */
      if ((ret = __db_c_get(dbc, skey, pkey, flags)) != 0) {
            /* Restore rskey/rkey/rdata and return. */
            pkey->flags = save_pkey_flags;
            dbc->rskey = dbc->rkey;
            dbc->rkey = dbc->rdata;
            dbc->rdata = save_rdata;
            goto err;
      }

      /* Restore pkey's flags in case we stomped the PARTIAL flag. */
      pkey->flags = save_pkey_flags;

      /*
       * Restore the cursor's rskey, rkey, and rdata DBTs.  If DB
       * is handling the memory management, we now have newly
       * reallocated buffers and ulens in rkey and rdata which we want
       * to put in rskey and rkey.  save_rdata contains the old value
       * of dbc->rdata.
       */
      dbc->rskey = dbc->rkey;
      dbc->rkey = dbc->rdata;
      dbc->rdata = save_rdata;

      /*
       * Now we're ready for "step 2".  If either or both of pkey and
       * data do not have memory management flags set--that is, if DB is
       * managing their memory--we need to swap around the rkey/rdata
       * structures so that we don't wind up trying to use memory managed
       * by the primary database cursor, which we'll close before we return.
       *
       * !!!
       * If you're carefully following the bouncing ball, you'll note
       * that in the DB-managed case, the buffer hanging off of pkey is
       * the same as dbc->rkey->data.  This is just fine;  we may well
       * realloc and stomp on it when we return, if we're going a
       * DB_GET_BOTH and need to return a different partial or key
       * (depending on the comparison function), but this is safe.
       *
       * !!!
       * We need to use __db_cursor_int here rather than simply calling
       * pdbp->cursor, because otherwise, if we're in CDB, we'll
       * allocate a new locker ID and leave ourselves open to deadlocks.
       * (Even though we're only acquiring read locks, we'll still block
       * if there are any waiters.)
       */
      if ((ret = __db_cursor_int(pdbp,
          dbc->txn, pdbp->type, PGNO_INVALID, 0, dbc->locker, &pdbc)) != 0)
            goto err;

      /*
       * We're about to use pkey a second time.  If DB_DBT_MALLOC
       * is set on it, we'll leak the memory we allocated the first time.
       * Thus, set DB_DBT_REALLOC instead so that we reuse that memory
       * instead of leaking it.
       *
       * !!!
       * This assumes that the user must always specify a compatible
       * realloc function if a malloc function is specified.  I think
       * this is a reasonable requirement.
       */
      if (F_ISSET(pkey, DB_DBT_MALLOC)) {
            F_CLR(pkey, DB_DBT_MALLOC);
            F_SET(pkey, DB_DBT_REALLOC);
            pkeymalloc = 1;
      }

      /*
       * Do the actual get.  Set DBC_TRANSIENT since we don't care
       * about preserving the position on error, and it's faster.
       * SET_RET_MEM so that the secondary DBC owns any returned-data
       * memory.
       */
      F_SET(pdbc, DBC_TRANSIENT);
      SET_RET_MEM(pdbc, dbc);
      ret = __db_c_get(pdbc, pkey, data, DB_SET);

      /*
       * If the item wasn't found in the primary, this is a bug;
       * our secondary has somehow gotten corrupted, and contains
       * elements that don't correspond to anything in the primary.
       * Complain.
       */
      if (ret == DB_NOTFOUND)
            ret = __db_secondary_corrupt(pdbp);

      /* Now close the primary cursor. */
      t_ret = __db_c_close(pdbc);

err:  if (pkeymalloc) {
            /*
             * If pkey had a MALLOC flag, we need to restore it;
             * otherwise, if the user frees the buffer but reuses
             * the DBT without NULL'ing its data field or changing
             * the flags, we may drop core.
             */
            F_CLR(pkey, DB_DBT_REALLOC);
            F_SET(pkey, DB_DBT_MALLOC);
      }
      return (t_ret == 0 ? ret : t_ret);
}

/*
 * __db_c_pget_recno --
 *    Perform a DB_GET_RECNO c_pget on a secondary index.  Returns
 * the secondary's record number in the pkey field and the primary's
 * in the data field.
 */
static int
__db_c_pget_recno(sdbc, pkey, data, flags)
      DBC *sdbc;
      DBT *pkey, *data;
      u_int32_t flags;
{
      DB *pdbp, *sdbp;
      DB_ENV *dbenv;
      DBC *pdbc;
      DBT discardme, primary_key;
      db_recno_t oob;
      u_int32_t rmw;
      int ret, t_ret;

      sdbp = sdbc->dbp;
      pdbp = sdbp->s_primary;
      dbenv = sdbp->dbenv;
      pdbc = NULL;
      ret = t_ret = 0;

      rmw = LF_ISSET(DB_RMW);

      memset(&discardme, 0, sizeof(DBT));
      F_SET(&discardme, DB_DBT_USERMEM | DB_DBT_PARTIAL);

      oob = RECNO_OOB;

      /*
       * If the primary is an rbtree, we want its record number, whether
       * or not the secondary is one too.  Fetch the recno into "data".
       *
       * If it's not an rbtree, return RECNO_OOB in "data".
       */
      if (F_ISSET(pdbp, DB_AM_RECNUM)) {
            /*
             * Get the primary key, so we can find the record number
             * in the primary. (We're uninterested in the secondary key.)
             */
            memset(&primary_key, 0, sizeof(DBT));
            F_SET(&primary_key, DB_DBT_MALLOC);
            if ((ret = __db_c_get(sdbc,
                &discardme, &primary_key, rmw | DB_CURRENT)) != 0)
                  return (ret);

            /*
             * Open a cursor on the primary, set it to the right record,
             * and fetch its recno into "data".
             *
             * (See __db_c_pget for comments on the use of __db_cursor_int.)
             *
             * SET_RET_MEM so that the secondary DBC owns any returned-data
             * memory.
             */
            if ((ret = __db_cursor_int(pdbp, sdbc->txn,
                pdbp->type, PGNO_INVALID, 0, sdbc->locker, &pdbc)) != 0)
                  goto perr;
            SET_RET_MEM(pdbc, sdbc);
            if ((ret = __db_c_get(pdbc,
                &primary_key, &discardme, rmw | DB_SET)) != 0)
                  goto perr;

            ret = __db_c_get(pdbc, &discardme, data, rmw | DB_GET_RECNO);

perr:       __os_ufree(sdbp->dbenv, primary_key.data);
            if (pdbc != NULL &&
                (t_ret = __db_c_close(pdbc)) != 0 && ret == 0)
                  ret = t_ret;
            if (ret != 0)
                  return (ret);
      } else if ((ret = __db_retcopy(dbenv, data, &oob,
                sizeof(oob), &sdbc->rkey->data, &sdbc->rkey->ulen)) != 0)
                  return (ret);

      /*
       * If the secondary is an rbtree, we want its record number, whether
       * or not the primary is one too.  Fetch the recno into "pkey".
       *
       * If it's not an rbtree, return RECNO_OOB in "pkey".
       */
      if (F_ISSET(sdbp, DB_AM_RECNUM))
            return (__db_c_get(sdbc, &discardme, pkey, flags));
      else
            return (__db_retcopy(dbenv, pkey, &oob,
                sizeof(oob), &sdbc->rdata->data, &sdbc->rdata->ulen));
}

/*
 * __db_wrlock_err -- do not have a write lock.
 */
static int
__db_wrlock_err(dbenv)
      DB_ENV *dbenv;
{
      __db_err(dbenv, "Write attempted on read-only cursor");
      return (EPERM);
}

/*
 * __db_c_del_secondary --
 *    Perform a delete operation on a secondary index:  call through
 *    to the primary and delete the primary record that this record
 *    points to.
 *
 *    Note that deleting the primary record will call c_del on all
 *    the secondaries, including this one;  thus, it is not necessary
 *    to execute both this function and an actual delete.
 */
static int
__db_c_del_secondary(dbc)
      DBC *dbc;
{
      DB *pdbp;
      DBC *pdbc;
      DBT skey, pkey;
      int ret, t_ret;

      memset(&skey, 0, sizeof(DBT));
      memset(&pkey, 0, sizeof(DBT));

      /*
       * Get the current item that we're pointing at.
       * We don't actually care about the secondary key, just
       * the primary.
       */
      F_SET(&skey, DB_DBT_PARTIAL | DB_DBT_USERMEM);
      if ((ret = __db_c_get(dbc, &skey, &pkey, DB_CURRENT)) != 0)
            return (ret);

      /*
       * Create a cursor on the primary with our locker ID,
       * so that when it calls back, we don't conflict.
       *
       * We create a cursor explicitly because there's no
       * way to specify the same locker ID if we're using
       * locking but not transactions if we use the DB->del
       * interface.  This shouldn't be any less efficient
       * anyway.
       */
      pdbp = dbc->dbp->s_primary;
      if ((ret = __db_cursor_int(pdbp, dbc->txn,
          pdbp->type, PGNO_INVALID, 0, dbc->locker, &pdbc)) != 0)
            return (ret);

      /*
       * See comment in __db_c_put--if we're in CDB,
       * we already hold the locks we need, and we need to flag
       * the cursor as a WRITER so we don't run into errors
       * when we try to delete.
       */
      if (CDB_LOCKING(pdbp->dbenv)) {
            DB_ASSERT(pdbc->mylock.off == LOCK_INVALID);
            F_SET(pdbc, DBC_WRITER);
      }

      /*
       * Set the new cursor to the correct primary key.  Then
       * delete it.  We don't really care about the datum;
       * just reuse our skey DBT.
       *
       * If the primary get returns DB_NOTFOUND, something is amiss--
       * every record in the secondary should correspond to some record
       * in the primary.
       */
      if ((ret = __db_c_get(pdbc, &pkey, &skey,
          (STD_LOCKING(dbc) ? DB_RMW : 0) | DB_SET)) == 0)
            ret = __db_c_del(pdbc, 0);
      else if (ret == DB_NOTFOUND)
            ret = __db_secondary_corrupt(pdbp);

      if ((t_ret = __db_c_close(pdbc)) != 0 && ret != 0)
            ret = t_ret;

      return (ret);
}

/*
 * __db_c_del_primary --
 *    Perform a delete operation on a primary index.  Loop through
 *    all the secondary indices which correspond to this primary
 *    database, and delete any secondary keys that point at the current
 *    record.
 *
 * PUBLIC: int __db_c_del_primary __P((DBC *));
 */
int
__db_c_del_primary(dbc)
      DBC *dbc;
{
      DB *dbp, *sdbp;
      DBC *sdbc;
      DBT data, pkey, skey, temppkey, tempskey;
      int ret, t_ret;

      dbp = dbc->dbp;

      /*
       * If we're called at all, we have at least one secondary.
       * (Unfortunately, we can't assert this without grabbing the mutex.)
       * Get the current record so that we can construct appropriate
       * secondary keys as needed.
       */
      memset(&pkey, 0, sizeof(DBT));
      memset(&data, 0, sizeof(DBT));
      if ((ret = __db_c_get(dbc, &pkey, &data, DB_CURRENT)) != 0)
            return (ret);

      for (sdbp = __db_s_first(dbp);
          sdbp != NULL && ret == 0; ret = __db_s_next(&sdbp)) {
            /*
             * Get the secondary key for this secondary and the current
             * item.
             */
            memset(&skey, 0, sizeof(DBT));
            if ((ret = sdbp->s_callback(sdbp, &pkey, &data, &skey)) != 0) {
                  /*
                   * If the current item isn't in this index, we
                   * have no work to do.  Proceed.
                   */
                  if (ret == DB_DONOTINDEX)
                        continue;

                  /* We had a substantive error.  Bail. */
                  FREE_IF_NEEDED(sdbp, &skey);
                  goto done;
            }

            /* Open a secondary cursor. */
            if ((ret = __db_cursor_int(sdbp, dbc->txn, sdbp->type,
                PGNO_INVALID, 0, dbc->locker, &sdbc)) != 0)
                  goto done;
            /* See comment above and in __db_c_put. */
            if (CDB_LOCKING(sdbp->dbenv)) {
                  DB_ASSERT(sdbc->mylock.off == LOCK_INVALID);
                  F_SET(sdbc, DBC_WRITER);
            }

            /*
             * Set the secondary cursor to the appropriate item.
             * Delete it.
             *
             * We want to use DB_RMW if locking is on;  it's only
             * legal then, though.
             *
             * !!!
             * Don't stomp on any callback-allocated buffer in skey
             * when we do a c_get(DB_GET_BOTH); use a temp DBT instead.
             * Similarly, don't allow pkey to be invalidated when the
             * cursor is closed.
             */
            memset(&tempskey, 0, sizeof(DBT));
            tempskey.data = skey.data;
            tempskey.size = skey.size;
            memset(&temppkey, 0, sizeof(DBT));
            temppkey.data = pkey.data;
            temppkey.size = pkey.size;
            if ((ret = __db_c_get(sdbc, &tempskey, &temppkey,
                (STD_LOCKING(dbc) ? DB_RMW : 0) | DB_GET_BOTH)) == 0)
                  ret = __db_c_del(sdbc, DB_UPDATE_SECONDARY);
            else if (ret == DB_NOTFOUND)
                  ret = __db_secondary_corrupt(dbp);

            FREE_IF_NEEDED(sdbp, &skey);

            if ((t_ret = __db_c_close(sdbc)) != 0 && ret == 0)
                  ret = t_ret;
            if (ret != 0)
                  goto done;
      }

done: if (sdbp != NULL && (t_ret = __db_s_done(sdbp)) != 0 && ret == 0)
            ret = t_ret;
      return (ret);
}

/*
 * __db_s_first --
 *    Get the first secondary, if any are present, from the primary.
 *
 * PUBLIC: DB *__db_s_first __P((DB *));
 */
DB *
__db_s_first(pdbp)
      DB *pdbp;
{
      DB *sdbp;

      MUTEX_THREAD_LOCK(pdbp->dbenv, pdbp->mutexp);
      sdbp = LIST_FIRST(&pdbp->s_secondaries);

      /* See __db_s_next. */
      if (sdbp != NULL)
            sdbp->s_refcnt++;
      MUTEX_THREAD_UNLOCK(pdbp->dbenv, pdbp->mutexp);

      return (sdbp);
}

/*
 * __db_s_next --
 *    Get the next secondary in the list.
 *
 * PUBLIC: int __db_s_next __P((DB **));
 */
int
__db_s_next(sdbpp)
      DB **sdbpp;
{
      DB *sdbp, *pdbp, *closeme;
      int ret;

      /*
       * Secondary indices are kept in a linked list, s_secondaries,
       * off each primary DB handle.  If a primary is free-threaded,
       * this list may only be traversed or modified while the primary's
       * thread mutex is held.
       *
       * The tricky part is that we don't want to hold the thread mutex
       * across the full set of secondary puts necessary for each primary
       * put, or we'll wind up essentially single-threading all the puts
       * to the handle;  the secondary puts will each take about as
       * long as the primary does, and may require I/O.  So we instead
       * hold the thread mutex only long enough to follow one link to the
       * next secondary, and then we release it before performing the
       * actual secondary put.
       *
       * The only danger here is that we might legitimately close a
       * secondary index in one thread while another thread is performing
       * a put and trying to update that same secondary index.  To
       * prevent this from happening, we refcount the secondary handles.
       * If close is called on a secondary index handle while we're putting
       * to it, it won't really be closed--the refcount will simply drop,
       * and we'll be responsible for closing it here.
       */
      sdbp = *sdbpp;
      pdbp = sdbp->s_primary;
      closeme = NULL;

      MUTEX_THREAD_LOCK(pdbp->dbenv, pdbp->mutexp);
      DB_ASSERT(sdbp->s_refcnt != 0);
      if (--sdbp->s_refcnt == 0) {
            LIST_REMOVE(sdbp, s_links);
            closeme = sdbp;
      }
      sdbp = LIST_NEXT(sdbp, s_links);
      if (sdbp != NULL)
            sdbp->s_refcnt++;
      MUTEX_THREAD_UNLOCK(pdbp->dbenv, pdbp->mutexp);

      *sdbpp = sdbp;

      /*
       * closeme->close() is a wrapper;  call __db_close explicitly.
       */
      ret = closeme != NULL ? __db_close(closeme, NULL, 0) : 0;
      return (ret);
}

/*
 * __db_s_done --
 *    Properly decrement the refcount on a secondary database handle we're
 *    using, without calling __db_s_next.
 *
 * PUBLIC: int __db_s_done __P((DB *));
 */
int
__db_s_done(sdbp)
      DB *sdbp;
{
      DB *pdbp;
      int doclose;

      pdbp = sdbp->s_primary;
      doclose = 0;

      MUTEX_THREAD_LOCK(pdbp->dbenv, pdbp->mutexp);
      DB_ASSERT(sdbp->s_refcnt != 0);
      if (--sdbp->s_refcnt == 0) {
            LIST_REMOVE(sdbp, s_links);
            doclose = 1;
      }
      MUTEX_THREAD_UNLOCK(pdbp->dbenv, pdbp->mutexp);

      return (doclose ? __db_close(sdbp, NULL, 0) : 0);
}

/*
 * __db_buildpartial --
 *    Build the record that will result after a partial put is applied to
 *    an existing record.
 *
 *    This should probably be merged with __bam_build, but that requires
 *    a little trickery if we plan to keep the overflow-record optimization
 *    in that function.
 */
static int
__db_buildpartial(dbp, oldrec, partial, newrec)
      DB *dbp;
      DBT *oldrec, *partial, *newrec;
{
      int ret;
      u_int8_t *buf;
      u_int32_t len, nbytes;

      DB_ASSERT(F_ISSET(partial, DB_DBT_PARTIAL));

      memset(newrec, 0, sizeof(DBT));

      nbytes = __db_partsize(oldrec->size, partial);
      newrec->size = nbytes;

      if ((ret = __os_malloc(dbp->dbenv, nbytes, &buf)) != 0)
            return (ret);
      newrec->data = buf;

      /* Nul or pad out the buffer, for any part that isn't specified. */
      memset(buf,
          F_ISSET(dbp, DB_AM_FIXEDLEN) ? ((BTREE *)dbp->bt_internal)->re_pad :
          0, nbytes);

      /* Copy in any leading data from the original record. */
      memcpy(buf, oldrec->data,
          partial->doff > oldrec->size ? oldrec->size : partial->doff);

      /* Copy the data from partial. */
      memcpy(buf + partial->doff, partial->data, partial->size);

      /* Copy any trailing data from the original record. */
      len = partial->doff + partial->dlen;
      if (oldrec->size > len)
            memcpy(buf + partial->doff + partial->size,
                (u_int8_t *)oldrec->data + len, oldrec->size - len);

      return (0);
}

/*
 * __db_partsize --
 *    Given the number of bytes in an existing record and a DBT that
 *    is about to be partial-put, calculate the size of the record
 *    after the put.
 *
 *    This code is called from __bam_partsize.
 *
 * PUBLIC: u_int32_t __db_partsize __P((u_int32_t, DBT *));
 */
u_int32_t
__db_partsize(nbytes, data)
      u_int32_t nbytes;
      DBT *data;
{

      /*
       * There are really two cases here:
       *
       * Case 1: We are replacing some bytes that do not exist (i.e., they
       * are past the end of the record).  In this case the number of bytes
       * we are replacing is irrelevant and all we care about is how many
       * bytes we are going to add from offset.  So, the new record length
       * is going to be the size of the new bytes (size) plus wherever those
       * new bytes begin (doff).
       *
       * Case 2: All the bytes we are replacing exist.  Therefore, the new
       * size is the oldsize (nbytes) minus the bytes we are replacing (dlen)
       * plus the bytes we are adding (size).
       */
      if (nbytes < data->doff + data->dlen)           /* Case 1 */
            return (data->doff + data->size);

      return (nbytes + data->size - data->dlen);      /* Case 2 */
}

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