mariadb/ft/xids.cc

/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:

#ident "$Id$"
/*
COPYING CONDITIONS NOTICE:

  This program is free software; you can redistribute it and/or modify
  it under the terms of version 2 of the GNU General Public License as
  published by the Free Software Foundation, and provided that the
  following conditions are met:

      * Redistributions of source code must retain this COPYING
        CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
        DISCLAIMER (below), the UNIVERSITY PATENT NOTICE (below), the
        PATENT MARKING NOTICE (below), and the PATENT RIGHTS
        GRANT (below).

      * Redistributions in binary form must reproduce this COPYING
        CONDITIONS NOTICE, the COPYRIGHT NOTICE (below), the
        DISCLAIMER (below), the UNIVERSITY PATENT NOTICE (below), the
        PATENT MARKING NOTICE (below), and the PATENT RIGHTS
        GRANT (below) in the documentation and/or other materials
        provided with the distribution.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  02110-1301, USA.

COPYRIGHT NOTICE:

  TokuDB, Tokutek Fractal Tree Indexing Library.
  Copyright (C) 2007-2013 Tokutek, Inc.

DISCLAIMER:

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

UNIVERSITY PATENT NOTICE:

  The technology is licensed by the Massachusetts Institute of
  Technology, Rutgers State University of New Jersey, and the Research
  Foundation of State University of New York at Stony Brook under
  United States of America Serial No. 11/760379 and to the patents
  and/or patent applications resulting from it.

PATENT MARKING NOTICE:

  This software is covered by US Patent No. 8,185,551.

PATENT RIGHTS GRANT:

  "THIS IMPLEMENTATION" means the copyrightable works distributed by
  Tokutek as part of the Fractal Tree project.

  "PATENT CLAIMS" means the claims of patents that are owned or
  licensable by Tokutek, both currently or in the future; and that in
  the absence of this license would be infringed by THIS
  IMPLEMENTATION or by using or running THIS IMPLEMENTATION.

  "PATENT CHALLENGE" shall mean a challenge to the validity,
  patentability, enforceability and/or non-infringement of any of the
  PATENT CLAIMS or otherwise opposing any of the PATENT CLAIMS.

  Tokutek hereby grants to you, for the term and geographical scope of
  the PATENT CLAIMS, a non-exclusive, no-charge, royalty-free,
  irrevocable (except as stated in this section) patent license to
  make, have made, use, offer to sell, sell, import, transfer, and
  otherwise run, modify, and propagate the contents of THIS
  IMPLEMENTATION, where such license applies only to the PATENT
  CLAIMS.  This grant does not include claims that would be infringed
  only as a consequence of further modifications of THIS
  IMPLEMENTATION.  If you or your agent or licensee institute or order
  or agree to the institution of patent litigation against any entity
  (including a cross-claim or counterclaim in a lawsuit) alleging that
  THIS IMPLEMENTATION constitutes direct or contributory patent
  infringement, or inducement of patent infringement, then any rights
  granted to you under this License shall terminate as of the date
  such litigation is filed.  If you or your agent or exclusive
  licensee institute or order or agree to the institution of a PATENT
  CHALLENGE, then Tokutek may terminate any rights granted to you
  under this License.
*/

#ident "Copyright (c) 2007-2013 Tokutek Inc.  All rights reserved."
#ident "The technology is licensed by the Massachusetts Institute of Technology, Rutgers State University of New Jersey, and the Research Foundation of State University of New York at Stony Brook under United States of America Serial No. 11/760379 and to the patents and/or patent applications resulting from it."

/* Purpose of this file is to implement xids list of nested transactions
 * ids.
 *
 * See design documentation for nested transactions at
 * TokuWiki/Imp/TransactionsOverview.
 *
 * NOTE: xids are always stored in disk byte order.  
 *       Accessors are responsible for transposing bytes to 
 *       host order.
 */


#include <errno.h>
#include <string.h>

#include <toku_portability.h>
#include "fttypes.h"
#include "xids.h"
#include "xids-internal.h"
#include "toku_assert.h"
#include "memory.h"
#include <toku_htod.h>


/////////////////////////////////////////////////////////////////////////////////
//  This layer of abstraction (xids_xxx) understands xids<> and nothing else.
//  It contains all the functions that understand xids<>
//
//  xids<> do not store the implicit transaction id of 0 at index 0.
//  The accessor functions make the id of 0 explicit at index 0.
//  The number of xids physically stored in the xids array is in
//  the variable num_xids.
//
// The xids struct is immutable.  The caller gets an initial version of XIDS
// by calling xids_get_root_xids(), which returns the constant struct
// representing the root transaction (id 0).  When a transaction begins, 
// a new XIDS is created with the id of the current transaction appended to
// the list.
// 
//


// This is the xids list for a transactionless environment.
// It is also the initial state of any xids list created for
// nested transactions.


XIDS
xids_get_root_xids(void) {
    static const struct xids_t root_xids = {
        .num_xids = 0
    };

    XIDS rval = (XIDS)&root_xids;
    return rval;
}

bool 
xids_can_create_child(XIDS xids) {
    invariant(xids->num_xids < MAX_TRANSACTION_RECORDS);
    return (xids->num_xids + 1) != MAX_TRANSACTION_RECORDS;
}


int
xids_create_unknown_child(XIDS parent_xids, XIDS *xids_p) {
    // Postcondition:
    //  xids_p points to an xids that is an exact copy of parent_xids, but with room for one more xid.
    int rval;
    invariant(parent_xids);
    uint32_t num_child_xids = parent_xids->num_xids + 1;
    // assumes that caller has verified that num_child_xids will
    // be less than MAX_TRANSACTIN_RECORDS
    invariant(num_child_xids < MAX_TRANSACTION_RECORDS);
    size_t new_size = sizeof(*parent_xids) + num_child_xids*sizeof(parent_xids->ids[0]);
    XIDS CAST_FROM_VOIDP(xids, toku_xmalloc(new_size));
    // Clone everything (parent does not have the newest xid).
    memcpy(xids, parent_xids, new_size - sizeof(xids->ids[0]));
    *xids_p = xids;
    rval = 0;
    return rval;
}

void
xids_finalize_with_child(XIDS xids, TXNID this_xid) {
    // Precondition:
    //  - xids was created by xids_create_unknown_child
    TXNID this_xid_disk = toku_htod64(this_xid);
    uint32_t num_child_xids = ++xids->num_xids;
    xids->ids[num_child_xids - 1] = this_xid_disk;
}

// xids is immutable.  This function creates a new xids by copying the
// parent's list and then appending the xid of the new transaction.
int
xids_create_child(XIDS   parent_xids,		// xids list for parent transaction
		  XIDS * xids_p,		// xids list created
		  TXNID  this_xid) {		// xid of this transaction (new innermost)
    bool can_create_child = xids_can_create_child(parent_xids);
    if (!can_create_child) {
        return EINVAL;
    }
    xids_create_unknown_child(parent_xids, xids_p);
    xids_finalize_with_child(*xids_p, this_xid);
    return 0;
}

void
xids_create_from_buffer(struct rbuf *rb,		// xids list for parent transaction
		        XIDS * xids_p) {		// xids list created
    uint8_t num_xids = rbuf_char(rb);
    invariant(num_xids < MAX_TRANSACTION_RECORDS);
    XIDS CAST_FROM_VOIDP(xids, toku_xmalloc(sizeof(*xids) + num_xids*sizeof(xids->ids[0])));
    xids->num_xids = num_xids;
    uint8_t index;
    for (index = 0; index < xids->num_xids; index++) {
        rbuf_TXNID(rb, &xids->ids[index]);
    }
    *xids_p = xids;
}


void
xids_destroy(XIDS *xids_p) {
    if (*xids_p != xids_get_root_xids()) toku_free(*xids_p);
    *xids_p = NULL;
}


// Return xid at requested position.  
// If requesting an xid out of range (which will be the case if xids array is empty)
// then return 0, the xid of the root transaction.
TXNID 
xids_get_xid(XIDS xids, uint8_t index) {
    invariant(index < xids_get_num_xids(xids));
    TXNID rval = xids->ids[index];
    rval = toku_dtoh64(rval);
    return rval;
}

uint8_t 
xids_get_num_xids(XIDS xids) {
    uint8_t rval = xids->num_xids;
    return rval;
}


// Return innermost xid 
TXNID 
xids_get_innermost_xid(XIDS xids) {
    TXNID rval = TXNID_NONE;
    if (xids_get_num_xids(xids)) {
        // if clause above makes this cast ok
        uint8_t innermost_xid = (uint8_t)(xids_get_num_xids(xids)-1);
        rval = xids_get_xid(xids, innermost_xid);
    }
    return rval;
}

TXNID
xids_get_outermost_xid(XIDS xids) {
    TXNID rval = TXNID_NONE;
    if (xids_get_num_xids(xids))
        rval = xids_get_xid(xids, 0);
    return rval;
}

void
xids_cpy(XIDS target, XIDS source) {
    size_t size = xids_get_size(source);
    memcpy(target, source, size);
}

// return size in bytes
uint32_t 
xids_get_size(XIDS xids){
    uint32_t rval;
    uint8_t num_xids = xids->num_xids;
    rval = sizeof(*xids) + num_xids * sizeof(xids->ids[0]);
    return rval;
}

uint32_t 
xids_get_serialize_size(XIDS xids){
    uint32_t rval;
    uint8_t num_xids = xids->num_xids;
    rval = 1 + //num xids
           8 * num_xids;
    return rval;
}


unsigned char *
xids_get_end_of_array(XIDS xids) {
    TXNID *r = xids->ids + xids->num_xids;
    return (unsigned char*)r;
}

void wbuf_nocrc_xids(struct wbuf *wb, XIDS xids) {
    wbuf_nocrc_char(wb, (unsigned char)xids->num_xids);
    uint8_t index;
    for (index = 0; index < xids->num_xids; index++) {
        wbuf_nocrc_TXNID(wb, xids->ids[index]);
    }
}

void
xids_fprintf(FILE* fp, XIDS xids) {
    uint8_t index;
    unsigned num_xids = xids_get_num_xids(xids);
    fprintf(fp, "[|%u| ", num_xids);
    for (index = 0; index < xids_get_num_xids(xids); index++) {
        if (index) fprintf(fp, ",");
        fprintf(fp, "%" PRIx64, xids_get_xid(xids, index));
    }
    fprintf(fp, "]");
}