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/* Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.
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,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */
#ifndef SQL_DIGEST_H
#define SQL_DIGEST_H
#include <string.h>
class String;
#include "my_md5.h"
#define MAX_DIGEST_STORAGE_SIZE (1024*1024)
/**
Structure to store token count/array for a statement
on which digest is to be calculated.
*/
struct sql_digest_storage
{
bool m_full;
uint m_byte_count;
unsigned char m_md5[MD5_HASH_SIZE];
/** Character set number. */
uint m_charset_number;
/**
Token array.
Token array is an array of bytes to store tokens received during parsing.
Following is the way token array is formed.
... <non-id-token> <non-id-token> <id-token> <id_len> <id_text> ...
For Example:
SELECT * FROM T1;
<SELECT_TOKEN> <*> <FROM_TOKEN> <ID_TOKEN> <2> <T1>
@note Only the first @c m_byte_count bytes are initialized,
out of @c m_token_array_length.
*/
unsigned char *m_token_array;
/* Length of the token array to be considered for DIGEST_TEXT calculation. */
uint m_token_array_length;
sql_digest_storage()
{
reset(NULL, 0);
}
inline void reset(unsigned char *token_array, size_t length)
{
m_token_array= token_array;
m_token_array_length= (uint)length;
reset();
}
inline void reset()
{
m_full= false;
m_byte_count= 0;
m_charset_number= 0;
memset(m_md5, 0, MD5_HASH_SIZE);
}
inline bool is_empty()
{
return (m_byte_count == 0);
}
inline void copy(const sql_digest_storage *from)
{
/*
Keep in mind this is a dirty copy of something that may change,
as the thread producing the digest is executing concurrently,
without any lock enforced.
*/
uint byte_count_copy= m_token_array_length < from->m_byte_count ?
m_token_array_length : from->m_byte_count;
if (byte_count_copy > 0)
{
m_full= from->m_full;
m_byte_count= byte_count_copy;
m_charset_number= from->m_charset_number;
memcpy(m_token_array, from->m_token_array, m_byte_count);
memcpy(m_md5, from->m_md5, MD5_HASH_SIZE);
}
else
{
m_full= false;
m_byte_count= 0;
m_charset_number= 0;
}
}
};
typedef struct sql_digest_storage sql_digest_storage;
/**
Compute a digest hash.
@param digest_storage The digest
@param [out] md5 The computed digest hash. This parameter is a buffer of size @c MD5_HASH_SIZE.
*/
void compute_digest_md5(const sql_digest_storage *digest_storage, unsigned char *md5);
/**
Compute a digest text.
A 'digest text' is a textual representation of a query,
where:
- comments are removed,
- non significant spaces are removed,
- literal values are replaced with a special '?' marker,
- lists of values are collapsed using a shorter notation
@param digest_storage The digest
@param [out] digest_text
@param digest_text_length Size of @c digest_text.
@param [out] truncated true if the text representation was truncated
*/
void compute_digest_text(const sql_digest_storage *digest_storage,
String *digest_text);
#endif
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