/* 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. ... &lt;non-id-token&gt; &lt;non-id-token&gt; &lt;id-token&gt; &lt;id_len&gt; &lt;id_text&gt; ... For Example: SELECT * FROM T1; &lt;SELECT_TOKEN&gt; &lt;*&gt; &lt;FROM_TOKEN&gt; &lt;ID_TOKEN&gt; &lt;2&gt; &lt;T1&gt; @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