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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, 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
+