new UDF arguments interface (WL#1017) (SCRUM)

include/mysql_com.h

@@ -278,6 +278,8 @@ typedef struct st_udf_args
   char **args;				/* Pointer to argument */
   unsigned long *lengths;		/* Length of string arguments */
   char *maybe_null;			/* Set to 1 for all maybe_null args */
+  char **attributes;                    /* Pointer to attribute name */
+  unsigned long *attribute_lengths;     /* Length of attribute arguments */
 } UDF_ARGS;
 
   /* This holds information about the result */

sql/item.cc

@@ -39,7 +39,7 @@ void item_init(void)
 }
 
 Item::Item():
-  fixed(0)
+  name_length(0), fixed(0)
 {
   marker= 0;
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
@@ -121,6 +121,7 @@ void Item::set_name(const char *str, uint length, CHARSET_INFO *cs)
   {
     /* Empty string, used by AS or internal function like last_insert_id() */
     name= (char*) str;
+    name_length= 0;
     return;
   }
   while (length && !my_isgraph(cs,*str))
@@ -131,12 +132,12 @@ void Item::set_name(const char *str, uint length, CHARSET_INFO *cs)
   if (!my_charset_same(cs, system_charset_info))
   {
     uint32 res_length;
-    name= sql_strmake_with_convert(str, length, cs,
+    name= sql_strmake_with_convert(str, name_length= length, cs,
 				   MAX_ALIAS_NAME, system_charset_info,
 				   &res_length);
   }
   else
-    name=sql_strmake(str, min(length,MAX_ALIAS_NAME));
+    name= sql_strmake(str, (name_length= min(length,MAX_ALIAS_NAME)));
 }
 
 

sql/item.h

@@ -106,6 +106,7 @@ class Item {
   my_string name;			/* Name from select */
   Item *next;
   uint32 max_length;
+  uint name_length;                     /* Length of name */
   uint8 marker,decimals;
   my_bool maybe_null;			/* If item may be null */
   my_bool null_value;			/* if item is null */

sql/item_func.cc

@@ -1498,11 +1498,16 @@ udf_handler::fix_fields(THD *thd, TABLE_LIST *tables, Item_result_field *func,
       const_item_cache&=item->const_item();
       f_args.arg_type[i]=item->result_type();
     }
+    //TODO: why all folowing memory is not allocated with 1 call of sql_alloc?
     if (!(buffers=new String[arg_count]) ||
 	!(f_args.args= (char**) sql_alloc(arg_count * sizeof(char *))) ||
-	!(f_args.lengths=(ulong*) sql_alloc(arg_count * sizeof(long))) ||
-	!(f_args.maybe_null=(char*) sql_alloc(arg_count * sizeof(char))) ||
-	!(num_buffer= (char*) sql_alloc(ALIGN_SIZE(sizeof(double))*arg_count)))
+	!(f_args.lengths= (ulong*) sql_alloc(arg_count * sizeof(long))) ||
+	!(f_args.maybe_null= (char*) sql_alloc(arg_count * sizeof(char))) ||
+	!(num_buffer= (char*) sql_alloc(arg_count *
+					ALIGN_SIZE(sizeof(double)))) ||
+	!(f_args.attributes= (char**) sql_alloc(arg_count * sizeof(char *))) ||
+	!(f_args.attribute_lengths= (ulong*) sql_alloc(arg_count *
+						       sizeof(long))))
     {
       free_udf(u_d);
       DBUG_RETURN(1);
@@ -1521,8 +1526,10 @@ udf_handler::fix_fields(THD *thd, TABLE_LIST *tables, Item_result_field *func,
     for (uint i=0; i < arg_count; i++)
     {
       f_args.args[i]=0;
-      f_args.lengths[i]=arguments[i]->max_length;
-      f_args.maybe_null[i]=(char) arguments[i]->maybe_null;
+      f_args.lengths[i]= arguments[i]->max_length;
+      f_args.maybe_null[i]= (char) arguments[i]->maybe_null;
+      f_args.attributes[i]= arguments[i]->name;
+      f_args.attribute_lengths[i]= arguments[i]->name_length;
 
       switch(arguments[i]->type()) {
       case Item::STRING_ITEM:			// Constant string !

sql/sql_parse.cc

@@ -2986,6 +2986,8 @@ mysql_execute_command(THD *thd)
 	break;
 #ifdef HAVE_DLOPEN
       sp_head *sph= sp_find_function(thd, &lex->udf.name);
+      // close & unlock table opened by sp_find_function
+      close_thread_tables(thd);
       if (sph)
       {
 	net_printf(thd, ER_UDF_EXISTS, lex->udf.name.str);

sql/sql_yacc.yy

@@ -630,13 +630,14 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 %type <item>
 	literal text_literal insert_ident order_ident
 	simple_ident select_item2 expr opt_expr opt_else sum_expr in_sum_expr
-	table_wild no_in_expr expr_expr simple_expr no_and_expr
+	table_wild no_in_expr expr_expr simple_expr no_and_expr udf_expr
 	using_list expr_or_default set_expr_or_default interval_expr
 	param_marker singlerow_subselect singlerow_subselect_init
 	exists_subselect exists_subselect_init sp_opt_default
 
 %type <item_list>
-	expr_list udf_expr_list when_list ident_list ident_list_arg
+	expr_list sp_expr_list udf_expr_list udf_expr_list2 when_list
+	ident_list ident_list_arg
 
 %type <key_type>
 	key_type opt_unique_or_fulltext
@@ -702,7 +703,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 	select_item_list select_item values_list no_braces
 	opt_limit_clause delete_limit_clause fields opt_values values
 	procedure_list procedure_list2 procedure_item
-	when_list2 expr_list2  handler
+	when_list2 expr_list2 udf_expr_list3 handler
 	opt_precision opt_ignore opt_column opt_restrict
 	grant revoke set lock unlock string_list field_options field_option
 	field_opt_list opt_binary table_lock_list table_lock
@@ -3246,7 +3247,7 @@ simple_expr:
 	  { $$= new Item_func_round($3,$5,1); }
 	| TRUE_SYM
 	  { $$= new Item_int((char*) "TRUE",1,1); }
-	| SP_FUNC '(' udf_expr_list ')'
+	| SP_FUNC '(' sp_expr_list ')'
 	  {
 	    sp_add_fun_to_lex(Lex, $1);
 	    if ($3)
@@ -3336,10 +3337,43 @@ simple_expr:
 	| EXTRACT_SYM '(' interval FROM expr ')'
 	{ $$=new Item_extract( $3, $5); };
 
-udf_expr_list:
+sp_expr_list:
 	/* empty */	{ $$= NULL; }
 	| expr_list	{ $$= $1;};
 
+udf_expr_list:
+	/* empty */	 { $$= NULL; }
+	| udf_expr_list2 { $$= $1;}
+	;
+
+udf_expr_list2:
+	{ Select->expr_list.push_front(new List<Item>); }
+	udf_expr_list3
+	{ $$= Select->expr_list.pop(); }
+	;
+
+udf_expr_list3:
+	udf_expr 
+	  {
+	    Select->expr_list.head()->push_back($1);
+	  }
+	| udf_expr_list3 ',' udf_expr 
+	  {
+	    Select->expr_list.head()->push_back($3);
+	  }
+	;
+
+udf_expr:
+	remember_name expr remember_end select_alias
+	{
+	  if ($4.str)
+	    $2->set_name($4.str,$4.length,system_charset_info);
+	  else
+	    $2->set_name($1,(uint) ($3 - $1), YYTHD->charset());
+	  $$= $2;
+	}
+	;
+
 sum_expr:
 	AVG_SYM '(' in_sum_expr ')'
 	  { $$=new Item_sum_avg($3); }

sql/udf_example.cc

@@ -56,7 +56,9 @@
 **
 ** Function 'myfunc_int' returns summary length of all its arguments.
 **
-** Function 'sequence' returns an sequence starting from a certain number
+** Function 'sequence' returns an sequence starting from a certain number.
+**
+** Function 'myfunc_argument_name' returns name of argument.
 **
 ** On the end is a couple of functions that converts hostnames to ip and
 ** vice versa.
@@ -82,6 +84,7 @@
 ** CREATE FUNCTION lookup RETURNS STRING SONAME "udf_example.so";
 ** CREATE FUNCTION reverse_lookup RETURNS STRING SONAME "udf_example.so";
 ** CREATE AGGREGATE FUNCTION avgcost RETURNS REAL SONAME "udf_example.so";
+** CREATE FUNCTION myfunc_argument_name RETURNS STRING SONAME "udf_example.so";
 **
 ** After this the functions will work exactly like native MySQL functions.
 ** Functions should be created only once.
@@ -94,6 +97,7 @@
 ** DROP FUNCTION lookup;
 ** DROP FUNCTION reverse_lookup;
 ** DROP FUNCTION avgcost;
+** DROP FUNCTION myfunc_argument_name;
 **
 ** The CREATE FUNCTION and DROP FUNCTION update the func@mysql table. All
 ** Active function will be reloaded on every restart of server
@@ -975,4 +979,46 @@ avgcost( UDF_INIT* initid, UDF_ARGS* args, char* is_null, char* error )
   return data->totalprice/double(data->totalquantity);
 }
 
+extern "C" {
+my_bool myfunc_argument_name_init(UDF_INIT *initid, UDF_ARGS *args,
+				  char *message);
+void myfunc_argument_name_deinit(UDF_INIT *initid);
+char *myfunc_argument_name(UDF_INIT *initid, UDF_ARGS *args, char *result,
+			   unsigned long *length, char *null_value,
+			   char *error);
+}
+
+my_bool myfunc_argument_name_init(UDF_INIT *initid, UDF_ARGS *args,
+				  char *message)
+{
+  if (args->arg_count != 1)
+  {
+    strmov(message,"myfunc_argument_name_init accepts only one argument");
+    return 1;
+  }
+  initid->max_length= args->attribute_lengths[0];
+  initid->maybe_null= 1;
+  initid->const_item= 1;
+  return 0;
+}
+
+void myfunc_argument_name_deinit(UDF_INIT *initid) {}
+
+char *myfunc_argument_name(UDF_INIT *initid, UDF_ARGS *args, char *result,
+			   unsigned long *length, char *null_value,
+			   char *error)
+{
+  if (!args->attributes[0])
+  {
+    null_value= 0;
+    return 0;
+  }
+  (*length)--; // space for ending \0 (for debugging purposes)
+  if (*length > args->attribute_lengths[0])
+    *length= args->attribute_lengths[0];
+  memcpy(result, args->attributes[0], *length);
+  result[*length]= 0;
+  return result;
+}
+
 #endif /* HAVE_DLOPEN */

tests/udf_test

@@ -9,6 +9,7 @@ CREATE FUNCTION myfunc_int RETURNS INTEGER SONAME "udf_example.so";
 CREATE FUNCTION lookup RETURNS STRING SONAME "udf_example.so";
 CREATE FUNCTION reverse_lookup RETURNS STRING SONAME "udf_example.so";
 CREATE AGGREGATE FUNCTION avgcost RETURNS REAL SONAME "udf_example.so";
+CREATE FUNCTION myfunc_argument_name RETURNS STRING SONAME "udf_example.so";
 
 select metaphon("hello"); 
 select myfunc_double("hello","world");
@@ -20,6 +21,7 @@ create temporary table t1 (a int,b double);
 insert into t1 values (1,5),(1,4),(2,8),(3,9),(4,11);
 select avgcost(a,b) from t1;
 select avgcost(a,b) from t1 group by a;
+select a, myfunc_argument_name(a) from t1;
 drop table t1;
 
 DROP FUNCTION metaphon;
@@ -28,3 +30,4 @@ DROP FUNCTION myfunc_int;
 DROP FUNCTION lookup;
 DROP FUNCTION reverse_lookup;
 DROP FUNCTION avgcost;
+DROP FUNCTION myfunc_argument_name;

tests/udf_test.res

@@ -34,6 +34,12 @@ CREATE AGGREGATE FUNCTION avgcost RETURNS REAL SONAME "udf_example.so"
 
 Query OK, 0 rows affected
 
+--------------
+CREATE FUNCTION myfunc_argument_name RETURNS STRING SONAME "udf_example.so"
+--------------
+
+Query OK, 0 rows affected
+
 --------------
 select metaphon("hello")
 --------------
@@ -106,6 +112,18 @@ avgcost(a,b)
 11.0000
 4 rows in set
 
+--------------
+select a, myfunc_argument_name(a) from t1;
+--------------
+
+a       myfunc_argument_name(a)
+1       a
+1       a
+2       a
+3       a
+4       a
+5 rows in set
+
 --------------
 drop table t1
 --------------
@@ -148,4 +166,10 @@ DROP FUNCTION avgcost
 
 Query OK, 0 rows affected
 
+--------------
+DROP FUNCTION myfunc_argument_name;
+--------------
+
+Query OK, 0 rows affected
+
 Bye