mariadb/include/my_bit.h
Thirunarayanan Balathandayuthapani cc810e64d4 MDEV-34392 Inplace algorithm violates the foreign key constraint
Don't allow the referencing key column from NULL TO NOT NULL
when

 1) Foreign key constraint type is ON UPDATE SET NULL
 2) Foreign key constraint type is ON DELETE SET NULL
 3) Foreign key constraint type is UPDATE CASCADE and referenced
 column declared as NULL

Don't allow the referenced key column from NOT NULL to NULL
when foreign key constraint type is UPDATE CASCADE
and referencing key columns doesn't allow NULL values

get_foreign_key_info(): InnoDB sends the information about
nullability of the foreign key fields and referenced key fields.

fk_check_column_changes(): Enforce the above rules for COPY
algorithm

innobase_check_foreign_drop_col(): Checks whether the dropped
column exists in existing foreign key relation

innobase_check_foreign_low() : Enforce the above rules for
INPLACE algorithm

dict_foreign_t::check_fk_constraint_valid(): This is used
by CREATE TABLE statement to check nullability for foreign
key relation.
2024-10-01 09:41:56 +05:30

224 lines
6.1 KiB
C

/* Copyright (c) 2007, 2011, Oracle and/or its affiliates.
Copyright (c) 2009, 2020, MariaDB Corporation.
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 02110-1335 USA */
#ifndef MY_BIT_INCLUDED
#define MY_BIT_INCLUDED
/*
Some useful bit functions
*/
C_MODE_START
extern const uchar _my_bits_reverse_table[256];
/*
my_bit_log2_xxx()
In the given value, find the highest bit set,
which is the smallest X that satisfies the condition: (2^X >= value).
Can be used as a reverse operation for (1<<X), to find X.
Examples:
- returns 0 for (1<<0)
- returns 1 for (1<<1)
- returns 2 for (1<<2)
- returns 2 for 3, which has (1<<2) as the highest bit set.
Note, the behaviour of log2(0) is not defined.
Let's return 0 for the input 0, for the code simplicity.
See the 000x branch. It covers both (1<<0) and 0.
*/
static inline CONSTEXPR uint my_bit_log2_hex_digit(uint8 value)
{
return value & 0x0C ? /*1100*/ (value & 0x08 ? /*1000*/ 3 : /*0100*/ 2) :
/*0010*/ (value & 0x02 ? /*0010*/ 1 : /*000x*/ 0);
}
static inline CONSTEXPR uint my_bit_log2_uint8(uint8 value)
{
return value & 0xF0 ? my_bit_log2_hex_digit((uint8) (value >> 4)) + 4:
my_bit_log2_hex_digit(value);
}
static inline CONSTEXPR uint my_bit_log2_uint16(uint16 value)
{
return value & 0xFF00 ? my_bit_log2_uint8((uint8) (value >> 8)) + 8 :
my_bit_log2_uint8((uint8) value);
}
static inline CONSTEXPR uint my_bit_log2_uint32(uint32 value)
{
return value & 0xFFFF0000UL ?
my_bit_log2_uint16((uint16) (value >> 16)) + 16 :
my_bit_log2_uint16((uint16) value);
}
static inline CONSTEXPR uint my_bit_log2_uint64(ulonglong value)
{
return value & 0xFFFFFFFF00000000ULL ?
my_bit_log2_uint32((uint32) (value >> 32)) + 32 :
my_bit_log2_uint32((uint32) value);
}
static inline CONSTEXPR uint my_bit_log2_size_t(size_t value)
{
#ifdef __cplusplus
static_assert(sizeof(size_t) <= sizeof(ulonglong),
"size_t <= ulonglong is an assumption that needs to be fixed "
"for this architecture. Please create an issue on "
"https://jira.mariadb.org");
#endif
return my_bit_log2_uint64((ulonglong) value);
}
/*
Count bits in 32bit integer
Algorithm by Sean Anderson, according to:
http://graphics.stanford.edu/~seander/bithacks.html
under "Counting bits set, in parallel"
(Original code public domain).
*/
static inline uint my_count_bits_uint32(uint32 v)
{
v = v - ((v >> 1) & 0x55555555);
v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
return (((v + (v >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24;
}
static inline uint my_count_bits(ulonglong x)
{
return my_count_bits_uint32((uint32)x) + my_count_bits_uint32((uint32)(x >> 32));
}
/*
Next highest power of two
SYNOPSIS
my_round_up_to_next_power()
v Value to check
RETURN
Next or equal power of 2
Note: 0 will return 0
NOTES
Algorithm by Sean Anderson, according to:
http://graphics.stanford.edu/~seander/bithacks.html
(Original code public domain)
Comments shows how this works with 01100000000000000000000000001011
*/
static inline uint32 my_round_up_to_next_power(uint32 v)
{
v--; /* 01100000000000000000000000001010 */
v|= v >> 1; /* 01110000000000000000000000001111 */
v|= v >> 2; /* 01111100000000000000000000001111 */
v|= v >> 4; /* 01111111110000000000000000001111 */
v|= v >> 8; /* 01111111111111111100000000001111 */
v|= v >> 16; /* 01111111111111111111111111111111 */
return v+1; /* 10000000000000000000000000000000 */
}
static inline uint32 my_clear_highest_bit(uint32 v)
{
uint32 w=v >> 1;
w|= w >> 1;
w|= w >> 2;
w|= w >> 4;
w|= w >> 8;
w|= w >> 16;
return v & w;
}
static inline uint32 my_reverse_bits(uint32 key)
{
return
((uint32)_my_bits_reverse_table[ key & 255] << 24) |
((uint32)_my_bits_reverse_table[(key>> 8) & 255] << 16) |
((uint32)_my_bits_reverse_table[(key>>16) & 255] << 8) |
(uint32)_my_bits_reverse_table[(key>>24) ];
}
/*
a number with the n lowest bits set
an overflow-safe version of (1 << n) - 1
*/
static inline uint64 my_set_bits(int n)
{
return (((1ULL << (n - 1)) - 1) << 1) | 1;
}
/* Create a mask of the significant bits for the last byte (1,3,7,..255) */
static inline uchar last_byte_mask(uint bits)
{
/* Get the number of used bits-1 (0..7) in the last byte */
unsigned int const used = (bits - 1U) & 7U;
/* Return bitmask for the significant bits */
return (uchar) ((2U << used) - 1);
}
static inline uint my_bits_in_bytes(uint n)
{
return ((n + 7) / 8);
}
#ifdef _MSC_VER
#include <intrin.h>
#endif
/*
Find the position of the first(least significant) bit set in
the argument. Returns 64 if the argument was 0.
*/
static inline uint my_find_first_bit(ulonglong n)
{
if(!n)
return 64;
#if defined(__GNUC__)
return __builtin_ctzll(n);
#elif defined(_MSC_VER)
#if defined(_M_IX86)
unsigned long bit;
if( _BitScanForward(&bit, (uint)n))
return bit;
_BitScanForward(&bit, (uint)(n>>32));
return bit + 32;
#else
unsigned long bit;
_BitScanForward64(&bit, n);
return bit;
#endif
#else
/* Generic case */
uint shift= 0;
static const uchar last_bit[16] = { 32, 0, 1, 0,
2, 0, 1, 0,
3, 0, 1, 0,
2, 0, 1, 0};
uint bit;
while ((bit = last_bit[(n >> shift) & 0xF]) == 32)
shift+= 4;
return shift+bit;
#endif
}
C_MODE_END
#endif /* MY_BIT_INCLUDED */