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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2009 - 2010 Toru Maesaka
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* 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.
*
* 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include "ha_blitz.h"
using namespace drizzled;
/* Given two native rows, this function checks all unique fields to
find whether the value has been updated. If a unique field value
is updated, it checks if the new key exists in the database already.
If it already exists, then it is a unique constraint violation. */
int ha_blitz::compare_rows_for_unique_violation(const unsigned char *old_row,
const unsigned char *new_row) {
const unsigned char *old_pos, *new_pos;
char *key, *fetched;
int key_len, fetched_len;
/* For now, we are only interested in supporting a PRIMARY KEY. In the
next phase of BlitzDB, this should loop through the key array. */
if (share->primary_key_exists) {
KeyInfo *pk = &getTable()->key_info[getTable()->getShare()->getPrimaryKey()];
KeyPartInfo *key_part = pk->key_part;
KeyPartInfo *key_part_end = key_part + pk->key_parts;
int key_changed = 0;
while (key_part != key_part_end) {
old_pos = old_row + key_part->offset;
new_pos = new_row + key_part->offset;
/* In VARCHAR, first 2 bytes is reserved to represent the length
of the key. Rip it out and move forward the row pointers. */
if (key_part->type == HA_KEYTYPE_VARTEXT2) {
uint16_t old_key_len = uint2korr(old_pos);
uint16_t new_key_len = uint2korr(new_pos);
old_pos += sizeof(old_key_len);
new_pos += sizeof(new_key_len);
/* Compare the actual data by repecting it's collation. */
key_changed = my_strnncoll(&my_charset_utf8_general_ci, old_pos,
old_key_len, new_pos, new_key_len);
} else if (key_part->type == HA_KEYTYPE_BINARY) {
return HA_ERR_UNSUPPORTED;
} else {
key_changed = memcmp(old_pos, new_pos, key_part->length);
}
key_part++;
}
/* Key has changed. Look up the database to see if the new value
would violate the unique contraint. */
if (key_changed) {
key = key_buffer;
key_len = make_index_key(key, getTable()->getMutableShare()->getPrimaryKey(), new_row);
fetched = share->dict.get_row(key, key_len, &fetched_len);
/* Key Exists. It's a violation. */
if (fetched != NULL) {
free(fetched);
this->errkey_id = getTable()->getShare()->getPrimaryKey();
return HA_ERR_FOUND_DUPP_KEY;
}
}
}
return 0;
}
/*
* Comparison Function for TC's B+Tree. This is the only function
* in BlitzDB where you can feel free to write redundant code for
* performance. Avoid function calls unless it is necessary. If
* you reaaaally want to separate the code block for readability,
* make sure to separate the code with C++ template for inlining.
* - Toru
* Currently Handles:
* INT (interpreted as LONG_INT)
* BIGINT (interpreted as LONGLONG)
* TIMESTAMP (interpreted as ULONG_INT)
* DATETIME (interpreted as ULONGLONG)
* DATE (interpreted as UINT_24)
* DOUBLE (interpreted as DOUBLE)
* VARCHAR (VARTEXT1 or VARTEXT2)
*
* BlitzDB Key Format:
* [DRIZZLE_KEY][UINT16_T][BLITZDB_UNIQUE_KEY]
*
* Returns:
* -1 = a < b
* 0 = a == b
* 1 = a > b
*/
int blitz_keycmp_cb(const char *a, int,
const char *b, int, void *opaque) {
BlitzTree *tree = (BlitzTree *)opaque;
int a_compared_len, b_compared_len, rv;
rv = packed_key_cmp(tree, a, b, &a_compared_len, &b_compared_len);
if (rv != 0)
return rv;
/* Getting here means that the Drizzle part of the keys are
identical. We now compare the BlitzDB part of the key. */
if (tree->unique) {
/* This is a special exception that allows Drizzle's NULL
key to be inserted duplicately into a UNIQUE tree. If
the keys aren't NULL then it is safe to conclude that
the keys are identical which this condition does. */
if (*a != 0 && *b != 0)
return 0;
}
char *a_pos = (char *)a + a_compared_len;
char *b_pos = (char *)b + b_compared_len;
uint16_t a_pk_len = uint2korr(a_pos);
uint16_t b_pk_len = uint2korr(b_pos);
a_pos += sizeof(a_pk_len);
b_pos += sizeof(b_pk_len);
if (a_pk_len == b_pk_len)
rv = memcmp(a_pos, b_pos, a_pk_len);
else if (a_pk_len < b_pk_len)
rv = -1;
else
rv = 1;
return rv;
}
/* General purpose comparison function for BlitzDB. We cannot reuse
blitz_keycmp_cb() for this purpose because the 'exact match' only
applies to BlitzDB's unique B+Tree key format in blitz_keycmp_cb().
Here we are comparing packed Drizzle keys. */
int packed_key_cmp(BlitzTree *tree, const char *a, const char *b,
int *a_compared_len, int *b_compared_len) {
BlitzKeyPart *curr_part;
char *a_pos = (char *)a;
char *b_pos = (char *)b;
int a_next_offset = 0;
int b_next_offset = 0;
*a_compared_len = 0;
*b_compared_len = 0;
for (int i = 0; i < tree->nparts; i++) {
curr_part = &tree->parts[i];
if (curr_part->null_bitmask) {
*a_compared_len += 1;
*b_compared_len += 1;
if (*a_pos != *b_pos)
return ((int)*a_pos - (int)*b_pos);
b_pos++;
if (!*a_pos++) {
curr_part++;
continue;
}
}
switch ((enum ha_base_keytype)curr_part->type) {
case HA_KEYTYPE_LONG_INT: {
int32_t a_int_val = sint4korr(a_pos);
int32_t b_int_val = sint4korr(b_pos);
*a_compared_len += curr_part->length;
*b_compared_len += curr_part->length;
if (a_int_val < b_int_val)
return -1;
else if (a_int_val > b_int_val)
return 1;
a_next_offset = b_next_offset = curr_part->length;
break;
}
case HA_KEYTYPE_ULONG_INT: {
uint32_t a_int_val = uint4korr(a_pos);
uint32_t b_int_val = uint4korr(b_pos);
*a_compared_len += curr_part->length;
*b_compared_len += curr_part->length;
if (a_int_val < b_int_val)
return -1;
else if (a_int_val > b_int_val)
return 1;
a_next_offset = b_next_offset = curr_part->length;
break;
}
case HA_KEYTYPE_LONGLONG: {
int64_t a_int_val = sint8korr(a_pos);
int64_t b_int_val = sint8korr(b_pos);
*a_compared_len += curr_part->length;
*b_compared_len += curr_part->length;
if (a_int_val < b_int_val)
return -1;
else if (a_int_val > b_int_val)
return 1;
a_next_offset = b_next_offset = curr_part->length;
break;
}
case HA_KEYTYPE_ULONGLONG: {
uint64_t a_int_val = uint8korr(a_pos);
uint64_t b_int_val = uint8korr(b_pos);
*a_compared_len += curr_part->length;
*b_compared_len += curr_part->length;
if (a_int_val < b_int_val)
return -1;
else if (a_int_val > b_int_val)
return 1;
a_next_offset = b_next_offset = curr_part->length;
break;
}
case HA_KEYTYPE_DOUBLE: {
double a_double_val, b_double_val;
float8get(a_double_val, a_pos);
float8get(b_double_val, b_pos);
*a_compared_len += curr_part->length;
*b_compared_len += curr_part->length;
if (a_double_val < b_double_val)
return -1;
else if (a_double_val > b_double_val)
return 1;
a_next_offset = b_next_offset = curr_part->length;
break;
}
case HA_KEYTYPE_VARTEXT1:
case HA_KEYTYPE_VARTEXT2: {
uint16_t a_varchar_len = uint2korr(a_pos);
uint16_t b_varchar_len = uint2korr(b_pos);
int key_changed;
a_pos += sizeof(a_varchar_len);
b_pos += sizeof(b_varchar_len);
*a_compared_len += a_varchar_len + sizeof(a_varchar_len);
*b_compared_len += b_varchar_len + sizeof(b_varchar_len);
/* Compare the texts by respecting collation. */
key_changed = my_strnncoll(&my_charset_utf8_general_ci,
(unsigned char *)a_pos, a_varchar_len,
(unsigned char *)b_pos, b_varchar_len);
if (key_changed < 0)
return -1;
else if (key_changed > 0)
return 1;
a_next_offset = a_varchar_len;
b_next_offset = b_varchar_len;
break;
}
default:
break;
}
a_pos += a_next_offset;
b_pos += b_next_offset;
curr_part++;
}
return 0;
}
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