MXS-1249: Add json functions

The json function are treated as read-only when the server version
is >= 10.2.3.
https://mariadb.com/kb/en/mariadb/json-functions/

query_classifier/qc_sqlite/builtin_functions.c

@@ -1,5 +1,14 @@
 /*
- * @licence@
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
  */
 
 #include "builtin_functions.h"
@@ -368,6 +377,42 @@ static const char* BUILTIN_FUNCTIONS[] =
 
 const size_t N_BUILTIN_FUNCTIONS = sizeof(BUILTIN_FUNCTIONS) / sizeof(BUILTIN_FUNCTIONS[0]);
 
+// The functions have been taken from:
+// https://mariadb.com/kb/en/mariadb/json-functions
+
+static const char* BUILTIN_10_2_3_FUNCTIONS[] =
+{
+    "json_array",
+    "json_array_append",
+    "json_array_insert",
+    "json_compact",
+    "json_contains",
+    "json_contains_path",
+    "json_depth",
+    "json_detailed",
+    "json_exists",
+    "json_extract",
+    "json_insert",
+    "json_keys",
+    "json_length",
+    "json_loose",
+    "json_merge",
+    "json_object",
+    "json_query",
+    "json_quote",
+    "json_remove"
+    "json_replace",
+    "json_search",
+    "json_set",
+    "json_type",
+    "json_unquote",
+    "json_valid",
+    "json_value"
+};
+
+const size_t N_BUILTIN_10_2_3_FUNCTIONS =
+    sizeof(BUILTIN_10_2_3_FUNCTIONS) / sizeof(BUILTIN_10_2_3_FUNCTIONS[0]);
+
 // NOTE: sort_compare and search_compare are not identical, so don't
 // NOTE: optimize either of them away.
 static int sort_compare(const void* key, const void* value)
@@ -389,6 +434,7 @@ void init_builtin_functions()
     ss_dassert(!unit.inited);
 
     qsort(BUILTIN_FUNCTIONS, N_BUILTIN_FUNCTIONS, sizeof(char*), sort_compare);
+    qsort(BUILTIN_10_2_3_FUNCTIONS, N_BUILTIN_10_2_3_FUNCTIONS, sizeof(char*), sort_compare);
 
     unit.inited = true;
 }
@@ -399,11 +445,22 @@ void finish_builtin_functions()
     unit.inited = false;
 }
 
-bool is_builtin_readonly_function(const char* key)
+bool is_builtin_readonly_function(const char* key, uint32_t major, uint32_t minor, uint32_t patch)
 {
     ss_dassert(unit.inited);
 
     char* value = bsearch(key, BUILTIN_FUNCTIONS, N_BUILTIN_FUNCTIONS, sizeof(char*), search_compare);
 
+    if (!value)
+    {
+        if ((major > 10) ||
+            ((major == 10) && (minor > 2)) ||
+            ((major == 10) && (minor == 2) && (patch >= 3)))
+        {
+            value = bsearch(key, BUILTIN_10_2_3_FUNCTIONS, N_BUILTIN_10_2_3_FUNCTIONS,
+                            sizeof(char*), search_compare);
+        }
+    }
+
     return value ? true : false;
 }

query_classifier/qc_sqlite/builtin_functions.h

@@ -1,11 +1,19 @@
-#ifndef BUILTIN_FUNCTIONS_H
-#define BUILTIN_FUNCTIONS_H
-/**
- * @LICENCE@
+#pragma once
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
  *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
  */
 
 #include <stdbool.h>
+#include <stdint.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -14,10 +22,8 @@ extern "C" {
 void init_builtin_functions();
 void finish_builtin_functions();
 
-bool is_builtin_readonly_function(const char* zToken);
+bool is_builtin_readonly_function(const char* zToken, uint32_t major, uint32_t minor, uint32_t patch);
 
 #ifdef __cplusplus
 }
 #endif
-
-#endif

query_classifier/qc_sqlite/qc_sqlite.c

@@ -1105,7 +1105,10 @@ static void update_field_infos(QC_SQLITE_INFO* info,
                 {
                     info->type_mask |= (QUERY_TYPE_READ | QUERY_TYPE_MASTER_READ);
                 }
-                else if (!is_builtin_readonly_function(zToken))
+                else if (!is_builtin_readonly_function(zToken,
+                                                       this_thread.version_major,
+                                                       this_thread.version_minor,
+                                                       this_thread.version_patch))
                 {
                     info->type_mask |= QUERY_TYPE_WRITE;
                 }