MDEV-5313 Improving audit API.

json_locate_key() implemented.
get rid of 'key_len' argument in functions.

include/json_lib.h

@@ -425,6 +425,11 @@ int json_path_compare(const json_path_t *a, const json_path_t *b,
 
 int json_valid(const char *js, size_t js_len, CHARSET_INFO *cs);
 
+int json_locate_key(const char *js, const char *js_end,
+                    const char *kname,
+                    const char **key_start, const char **key_end,
+                    int *comma_pos);
+
 #ifdef  __cplusplus
 }
 #endif

include/mysql/plugin_audit.h.pp

@@ -393,7 +393,7 @@ extern struct json_service_st {
                                          int n_item,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_key)(const char *js, const char *js_end,
-                                         const char *key, const char *key_end,
+                                         const char *key,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_nkey)(const char *js,const char *js_end,
                              int nkey,
@@ -410,7 +410,7 @@ enum json_types json_get_array_item(const char *js, const char *js_end,
                                     int n_item,
                                     const char **value, int *value_len);
 enum json_types json_get_object_key(const char *js, const char *js_end,
-                                    const char *key, const char *key_end,
+                                    const char *key,
                                     const char **value, int *value_len);
 enum json_types json_get_object_nkey(const char *js,const char *js_end, int nkey,
                        const char **keyname, const char **keyname_end,

include/mysql/plugin_auth.h.pp

@@ -393,7 +393,7 @@ extern struct json_service_st {
                                          int n_item,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_key)(const char *js, const char *js_end,
-                                         const char *key, const char *key_end,
+                                         const char *key,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_nkey)(const char *js,const char *js_end,
                              int nkey,
@@ -410,7 +410,7 @@ enum json_types json_get_array_item(const char *js, const char *js_end,
                                     int n_item,
                                     const char **value, int *value_len);
 enum json_types json_get_object_key(const char *js, const char *js_end,
-                                    const char *key, const char *key_end,
+                                    const char *key,
                                     const char **value, int *value_len);
 enum json_types json_get_object_nkey(const char *js,const char *js_end, int nkey,
                        const char **keyname, const char **keyname_end,

include/mysql/plugin_encryption.h.pp

@@ -393,7 +393,7 @@ extern struct json_service_st {
                                          int n_item,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_key)(const char *js, const char *js_end,
-                                         const char *key, const char *key_end,
+                                         const char *key,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_nkey)(const char *js,const char *js_end,
                              int nkey,
@@ -410,7 +410,7 @@ enum json_types json_get_array_item(const char *js, const char *js_end,
                                     int n_item,
                                     const char **value, int *value_len);
 enum json_types json_get_object_key(const char *js, const char *js_end,
-                                    const char *key, const char *key_end,
+                                    const char *key,
                                     const char **value, int *value_len);
 enum json_types json_get_object_nkey(const char *js,const char *js_end, int nkey,
                        const char **keyname, const char **keyname_end,

include/mysql/plugin_ftparser.h.pp

@@ -393,7 +393,7 @@ extern struct json_service_st {
                                          int n_item,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_key)(const char *js, const char *js_end,
-                                         const char *key, const char *key_end,
+                                         const char *key,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_nkey)(const char *js,const char *js_end,
                              int nkey,
@@ -410,7 +410,7 @@ enum json_types json_get_array_item(const char *js, const char *js_end,
                                     int n_item,
                                     const char **value, int *value_len);
 enum json_types json_get_object_key(const char *js, const char *js_end,
-                                    const char *key, const char *key_end,
+                                    const char *key,
                                     const char **value, int *value_len);
 enum json_types json_get_object_nkey(const char *js,const char *js_end, int nkey,
                        const char **keyname, const char **keyname_end,

include/mysql/plugin_password_validation.h.pp

@@ -393,7 +393,7 @@ extern struct json_service_st {
                                          int n_item,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_key)(const char *js, const char *js_end,
-                                         const char *key, const char *key_end,
+                                         const char *key,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_nkey)(const char *js,const char *js_end,
                              int nkey,
@@ -410,7 +410,7 @@ enum json_types json_get_array_item(const char *js, const char *js_end,
                                     int n_item,
                                     const char **value, int *value_len);
 enum json_types json_get_object_key(const char *js, const char *js_end,
-                                    const char *key, const char *key_end,
+                                    const char *key,
                                     const char **value, int *value_len);
 enum json_types json_get_object_nkey(const char *js,const char *js_end, int nkey,
                        const char **keyname, const char **keyname_end,

include/mysql/service_json.h

@@ -66,7 +66,7 @@ extern struct json_service_st {
                                          int n_item,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_key)(const char *js, const char *js_end,
-                                         const char *key, const char *key_end,
+                                         const char *key,
                                          const char **value, int *value_len);
   enum json_types (*json_get_object_nkey)(const char *js,const char *js_end,
                              int nkey,
@@ -95,7 +95,7 @@ enum json_types json_get_array_item(const char *js, const char *js_end,
                                     int n_item,
                                     const char **value, int *value_len);
 enum json_types json_get_object_key(const char *js, const char *js_end,
-                                    const char *key, const char *key_end,
+                                    const char *key,
                                     const char **value, int *value_len);
 enum json_types json_get_object_nkey(const char *js,const char *js_end, int nkey,
                        const char **keyname, const char **keyname_end,

strings/json_lib.c

@@ -1943,9 +1943,10 @@ enum json_types json_get_array_item(const char *js, const char *js_end,
   @retval JSV_NOTHING - no such key found.
 */
 enum json_types json_get_object_key(const char *js, const char *js_end,
-                                    const char *key, const char *key_end,
+                                    const char *key,
                                     const char **value, int *value_len)
 {
+  const char *key_end= key + strlen(key);
   json_engine_t je;
   json_string_t key_name;
   int n_keys= 0;
@@ -1999,10 +2000,99 @@ enum json_types json_get_object_nkey(const char *js,const char *js_end, int nkey
 
   @retval 0 - success, json is well-formed
   @retval 1 - error, json is invalid
-*/int json_valid(const char *js, size_t js_len, CHARSET_INFO *cs)
+*/
+int json_valid(const char *js, size_t js_len, CHARSET_INFO *cs)
 {
   json_engine_t je;
   json_scan_start(&je, cs, (const uchar *) js, (const uchar *) js + js_len);
   while (json_scan_next(&je) == 0) /* no-op */ ;
   return je.s.error == 0;
 }
+
+
+/*
+  Expects the JSON object as an js argument, and the key name.
+  Looks for this key in the object and returns
+  the location of all the text related to it.
+  The text includes the comma, separating this key.
+
+  comma_pos - the hint where the comma is. It is important
+       if you plan to replace the key rather than just cut.
+    1  - comma is on the left
+    2  - comma is on the right.
+    0  - no comma at all (the object has just this single key)
+ 
+  if no such key found *key_start is set to NULL.
+*/
+int json_locate_key(const char *js, const char *js_end,
+                    const char *kname,
+                    const char **key_start, const char **key_end,
+                    int *comma_pos)
+{
+  const char *kname_end= kname + strlen(kname);
+  json_engine_t je;
+  json_string_t key_name;
+  int t_next, c_len, match_result;
+
+  json_string_set_cs(&key_name, &my_charset_utf8mb4_bin);
+
+  json_scan_start(&je, &my_charset_utf8mb4_bin,(const uchar *) js,
+                  (const uchar *) js_end);
+
+  if (json_read_value(&je) ||
+      je.value_type != JSON_VALUE_OBJECT)
+    goto err_return;
+
+  *key_start= (const char *) je.s.c_str;
+  *comma_pos= 0;
+
+  while (!json_scan_next(&je))
+  {
+    switch (je.state)
+    {
+    case JST_KEY:
+      json_string_set_str(&key_name, (const uchar *) kname,
+                          (const uchar *) kname_end);
+      match_result= json_key_matches(&je, &key_name);
+      if (json_skip_key(&je))
+        goto err_return;
+      get_first_nonspace(&je.s, &t_next, &c_len);
+      je.s.c_str-= c_len;
+
+      if (match_result)
+      {
+        *key_end= (const char *) je.s.c_str;
+
+        if (*comma_pos == 1)
+          return 0;
+
+        DBUG_ASSERT(*comma_pos == 0);
+
+        if (t_next == C_COMMA)
+        {
+          *key_end+= c_len;
+          *comma_pos= 2;
+        }
+        else if (t_next == C_RCURB)
+          *comma_pos= 0;
+        else
+          goto err_return;
+        return 0;
+      }
+
+      *key_start= (const char *) je.s.c_str;
+      *comma_pos= 1;
+      break;
+
+    case JST_OBJ_END:
+      *key_start= NULL;
+      return 0;
+    }
+  }
+
+err_return:
+  return 1;
+
+}
+
+

unittest/strings/json-t.c

@@ -17,21 +17,29 @@
 #include <my_sys.h>
 #include <json_lib.h>
 
+int json_locate_key(const char *js, const char *js_end, const char *kname,
+                    const char **key_start, const char **key_end,
+                    int *comma_pos);
 int main()
 {
   const char *json="{\"int\":1, \"str\":\"foo bar\", "
                    "\"array\":[10,20,{\"c\":\"d\"}],\"bool\":false}";
   const char *json_ar="[1, \"foo bar\", " "[10,20,{\"c\":\"d\"}], false]";
+  const char *json_w="{\"int\" : 1 , \"str\" : \"foo bar\" , "
+                   "\"array\" : [10,20,{\"c\":\"d\"}]  , \"bool\" : false  }";
+  const char *json_1="{ \"str\" : \"foo bar\"   }";
   enum json_types value_type;
   const char *value_start;
   int value_len;
+  const char *key_start, *key_end;
+  int result, comma_pos;
 
-  plan(10);
+  plan(15);
 
 #define do_json(V)                                                      \
   do {                                                                  \
     value_type= json_get_object_key(json, json+strlen(json),            \
-                  V, V + (sizeof(V) - 1),&value_start, &value_len);     \
+                  V, &value_start, &value_len);                         \
     ok(value_type != JSV_BAD_JSON, V);                                  \
     diag("type=%d, value=\"%.*s\"", value_type, (int)value_len, value_start); \
   } while(0)
@@ -42,6 +50,16 @@ int main()
     ok(value_type != JSV_BAD_JSON, #N);                      \
     diag("type=%d, value=\"%.*s\"", value_type, (int)value_len, value_start); \
   } while(0)
+#define do_json_locate(J, V)                              \
+  do {                                                    \
+    result= json_locate_key(J, J+strlen(J),               \
+                  V, &key_start, &key_end, &comma_pos);   \
+    ok(result == 0, V);                                   \
+    if (key_start)                                        \
+      diag("key_str=\"%.*s\" comma_pos= %d", (int)(key_end - key_start), key_start, comma_pos); \
+    else                                                                                    \
+      diag("no key found"); \
+  } while(0)
 
   do_json("int");
   do_json("str");
@@ -54,5 +72,11 @@ int main()
   do_json_ar(2);
   do_json_ar(3);
   do_json_ar(4);
+
+  do_json_locate(json_w, "bool");
+  do_json_locate(json_w, "int");
+  do_json_locate(json_w, "array");
+  do_json_locate(json_1, "str");
+  do_json_locate(json_w, "c");
   return exit_status();
 }