/* -*- mode: C; c-basic-offset: 4 -*- */
#ident "Copyright (c) 2007, 2008 Tokutek Inc. All rights reserved."
/* 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 "brttypes.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_stored_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_stored_xids = 0
};
XIDS rval = (XIDS)&root_xids;
return rval;
}
// 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)
int rval;
assert(parent_xids);
assert(this_xid > xids_get_innermost_xid(parent_xids));
u_int32_t num_stored_xids = parent_xids->num_stored_xids + 1;
u_int32_t num_xids = num_stored_xids + 1;
assert(num_xids > 0);
assert(num_xids <= MAX_TRANSACTION_RECORDS + 1);
if (num_xids > MAX_TRANSACTION_RECORDS) rval = EINVAL;
else {
XIDS xids = toku_malloc(sizeof(*xids) + num_stored_xids*sizeof(xids->ids[0]));
if (!xids) rval = ENOMEM;
else {
xids->num_stored_xids = num_stored_xids;
memcpy(xids->ids,
parent_xids->ids,
parent_xids->num_stored_xids*sizeof(parent_xids->ids[0]));
TXNID this_xid_disk = toku_htod64(this_xid);
xids->ids[num_stored_xids-1] = this_xid_disk;
*xids_p = xids;
rval = 0;
}
}
return rval;
}
void
xids_create_from_buffer(struct rbuf *rb, // xids list for parent transaction
XIDS * xids_p) { // xids list created
u_int32_t num_stored_xids = rbuf_char(rb);
u_int32_t num_xids = num_stored_xids + 1;
assert(num_xids > 0);
assert(num_xids <= MAX_TRANSACTION_RECORDS);
XIDS xids = toku_xmalloc(sizeof(*xids) + num_stored_xids*sizeof(xids->ids[0]));
xids->num_stored_xids = num_stored_xids;
u_int8_t index;
for (index = 0; index < xids->num_stored_xids; index++) {
rbuf_TXNID(rb, &xids->ids[index]);
if (index > 0)
assert(xids->ids[index] > xids->ids[index-1]);
}
*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, u_int8_t index) {
TXNID rval = 0;
if (index > 0) {
assert(index < xids_get_num_xids(xids));
rval = xids->ids[index-1];
rval = toku_dtoh64(rval);
}
return rval;
}
// This function assumes that target_xid IS in the list
// of xids.
u_int8_t
xids_find_index_of_xid(XIDS xids, TXNID target_xid) {
u_int8_t index = 0; // search outer to inner
TXNID current_xid = xids_get_xid(xids, index);
while (current_xid != target_xid) {
assert(current_xid < target_xid);
index++;
current_xid = xids_get_xid(xids, index); // Next inner txnid in xids.
}
return index;
}
u_int8_t
xids_get_num_xids(XIDS xids) {
u_int8_t rval = xids->num_stored_xids+1; //+1 for the id of 0 made explicit by xids<> accessors
return rval;
}
// Return innermost xid
TXNID
xids_get_innermost_xid(XIDS xids) {
TXNID rval = xids_get_xid(xids, xids_get_num_xids(xids)-1);
return rval;
}
void
xids_cpy(XIDS target, XIDS source) {
size_t size = xids_get_size(source);
memcpy(target, source, size);
}
// return size in bytes
u_int32_t
xids_get_size(XIDS xids){
u_int32_t rval;
u_int8_t num_stored_xids = xids->num_stored_xids;
rval = sizeof(*xids) + num_stored_xids * sizeof(xids->ids[0]);
return rval;
}
u_int32_t
xids_get_serialize_size(XIDS xids){
u_int32_t rval;
u_int8_t num_stored_xids = xids->num_stored_xids;
rval = 1 + //num stored xids
8 * num_stored_xids;
return rval;
}
void
toku_calc_more_murmur_xids (struct x1764 *mm, XIDS xids) {
x1764_add(mm, &xids->num_stored_xids, 1);
u_int8_t index;
u_int8_t num_xids = xids_get_num_xids(xids);
for (index = 0; index < num_xids; index++) {
TXNID current_xid = xids_get_xid(xids, index);
x1764_add(mm, ¤t_xid, 8);
}
}
unsigned char *
xids_get_end_of_array(XIDS xids) {
TXNID *r = xids->ids + xids->num_stored_xids;
return (unsigned char*)r;
}
void wbuf_xids(struct wbuf *wb, XIDS xids) {
wbuf_char(wb, (unsigned char)xids->num_stored_xids);
u_int8_t index;
for (index = 0; index < xids->num_stored_xids; index++) {
wbuf_TXNID(wb, xids->ids[index]);
}
}
void
xids_fprintf(FILE* fp, XIDS xids) {
u_int8_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, "]");
}