## root/libdb/bt_close.c

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## DEFINITIONS

This source file includes following definitions.

1. __bt_close
2. __bt_sync
3. bt_meta

    /*-
     * Copyright (c) 1990, 1993, 1994
     *      The Regents of the University of California.  All rights reserved.
     *
     * This code is derived from software contributed to Berkeley by
     * Mike Olson.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */

    #if defined(LIBC_SCCS) && !defined(lint)
    static char sccsid[] = "@(#)bt_close.c  8.7 (Berkeley) 8/17/94";
    #endif /* LIBC_SCCS and not lint */

    #ifdef HAVE_CONFIG_H
    #include <config.h>
    #endif
    #include <errno.h>
    #include <stdio.h>
    #ifdef STDC_HEADERS
    #include <stdlib.h>
    #endif
    #ifdef HAVE_STRING_H
    #include <string.h>
    #else
    #include <strings.h>
    #endif
    #ifdef HAVE_UNISTD_H
    #include <unistd.h>
    #endif

    #include "db.h"
    #include "btree.h"

    static int bt_meta(BTREE *);

    /*
     * BT_CLOSE -- Close a btree.
     *
     * Parameters:
     *      dbp:    pointer to access method
     *      abandon: 1: don't sync, 0: sync
     *
     * Returns:
     *      RET_ERROR, RET_SUCCESS
     */
    int
    __bt_close(dbp, abandon)
            DB *dbp;
            int abandon;
    {
            BTREE *t;
            int fd;

            t = dbp->internal;

            /* Toss any page pinned across calls. */
            if (t->bt_pinned != NULL) {
                    mpool_put(t->bt_mp, t->bt_pinned, 0);
                    t->bt_pinned = NULL;
            }

            /* Sync the tree. */
            /*
             * If abandon flag is set, omit writing to the disk.
             * Since the writing spend much time, you should use this flag
             * when you remove the file after closing.
             */
            if (!abandon && __bt_sync(dbp, 0) == RET_ERROR)
                    return (RET_ERROR);

            /* Close the memory pool. */
            if (mpool_close(t->bt_mp) == RET_ERROR)
                    return (RET_ERROR);

            /* Free random memory. */
            if (t->bt_cursor.key.data != NULL) {
                    free(t->bt_cursor.key.data);
                    t->bt_cursor.key.size = 0;
                    t->bt_cursor.key.data = NULL;
            }
            if (t->bt_rkey.data) {
                    free(t->bt_rkey.data);
                    t->bt_rkey.size = 0;
                    t->bt_rkey.data = NULL;
            }
            if (t->bt_rdata.data) {
                    free(t->bt_rdata.data);
                    t->bt_rdata.size = 0;
                    t->bt_rdata.data = NULL;
            }

            fd = t->bt_fd;
            free(t);
            free(dbp);
            return (close(fd) ? RET_ERROR : RET_SUCCESS);
    }

    /*
     * BT_SYNC -- sync the btree to disk.
     *
     * Parameters:
     *      dbp:    pointer to access method
     *
     * Returns:
     *      RET_SUCCESS, RET_ERROR.
     */
    int
    __bt_sync(dbp, flags)
            const DB *dbp;
            u_int flags;
    {
            BTREE *t;
            int status;

            t = dbp->internal;

            /* Toss any page pinned across calls. */
            if (t->bt_pinned != NULL) {
                    mpool_put(t->bt_mp, t->bt_pinned, 0);
                    t->bt_pinned = NULL;
            }

            /* Sync doesn't currently take any flags. */
            if (flags != 0) {
                    errno = EINVAL;
                    return (RET_ERROR);
            }

            if (F_ISSET(t, B_INMEM | B_RDONLY) || !F_ISSET(t, B_MODIFIED))
                    return (RET_SUCCESS);

            if (F_ISSET(t, B_METADIRTY) && bt_meta(t) == RET_ERROR)
                    return (RET_ERROR);

            if ((status = mpool_sync(t->bt_mp)) == RET_SUCCESS)
                    F_CLR(t, B_MODIFIED);

            return (status);
    }

    /*
     * BT_META -- write the tree meta data to disk.
     *
     * Parameters:
     *      t:      tree
     *
     * Returns:
     *      RET_ERROR, RET_SUCCESS
     */
    static int
    bt_meta(t)
            BTREE *t;
    {
            BTMETA m;
            void *p;

            if ((p = mpool_get(t->bt_mp, P_META, 0)) == NULL)
                    return (RET_ERROR);

            /* Fill in metadata. */
            m.magic = BTREEMAGIC;
            m.version = BTREEVERSION;
            m.psize = t->bt_psize;
            m.free = t->bt_free;
            m.nrecs = t->bt_nrecs;
            m.flags = F_ISSET(t, SAVEMETA);

            memmove(p, &m, sizeof(BTMETA));
            mpool_put(t->bt_mp, p, MPOOL_DIRTY);
            return (RET_SUCCESS);
    }

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