diff options
Diffstat (limited to 'sql/sql_digest.h')
| -rw-r--r-- | sql/sql_digest.h | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/sql/sql_digest.h b/sql/sql_digest.h new file mode 100644 index 00000000..cc786a3b --- /dev/null +++ b/sql/sql_digest.h @@ -0,0 +1,129 @@ +/* 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, Fifth Floor, 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 + |