MDEV-31153 New methods Schema::make_item_func_* for REPLACE, SUBSTRING, TRIM

Adding virtual methods to class Schema:

  make_item_func_replace()
  make_item_func_substr()
  make_item_func_trim()

This is a non-functional preparatory change for MDEV-27744.

sql/sql_lex.cc

@@ -8639,33 +8639,6 @@ bool LEX::add_grant_command(THD *thd, enum_sql_command sql_command_arg,
 }
 
 
-Item *LEX::make_item_func_substr(THD *thd, Item *a, Item *b, Item *c)
-{
-  return (thd->variables.sql_mode & MODE_ORACLE) ?
-    new (thd->mem_root) Item_func_substr_oracle(thd, a, b, c) :
-    new (thd->mem_root) Item_func_substr(thd, a, b, c);
-}
-
-
-Item *LEX::make_item_func_substr(THD *thd, Item *a, Item *b)
-{
-  return (thd->variables.sql_mode & MODE_ORACLE) ?
-    new (thd->mem_root) Item_func_substr_oracle(thd, a, b) :
-    new (thd->mem_root) Item_func_substr(thd, a, b);
-}
-
-
-Item *LEX::make_item_func_replace(THD *thd,
-                                  Item *org,
-                                  Item *find,
-                                  Item *replace)
-{
-  return (thd->variables.sql_mode & MODE_ORACLE) ?
-    new (thd->mem_root) Item_func_replace_oracle(thd, org, find, replace) :
-    new (thd->mem_root) Item_func_replace(thd, org, find, replace);
-}
-
-
 bool SELECT_LEX::vers_push_field(THD *thd, TABLE_LIST *table,
                                  const LEX_CSTRING field_name)
 {

sql/sql_lex.h

@@ -4033,9 +4033,6 @@ public:
 
   Item *create_item_query_expression(THD *thd, st_select_lex_unit *unit);
 
-  Item *make_item_func_replace(THD *thd, Item *org, Item *find, Item *replace);
-  Item *make_item_func_substr(THD *thd, Item *a, Item *b, Item *c);
-  Item *make_item_func_substr(THD *thd, Item *a, Item *b);
   Item *make_item_func_call_generic(THD *thd, Lex_ident_cli_st *db,
                                     Lex_ident_cli_st *name, List<Item> *args);
   Item *make_item_func_call_generic(THD *thd,

sql/sql_schema.cc

@@ -32,6 +32,14 @@ public:
       return thd->type_handler_for_datetime();
     return src;
   }
+
+  Item *make_item_func_replace(THD *thd,
+                               Item *subj,
+                               Item *find,
+                               Item *replace) const;
+  Item *make_item_func_substr(THD *thd,
+                              const Lex_substring_spec_st &spec) const;
+  Item *make_item_func_trim(THD *thd, const Lex_trim_st &spec) const;
 };
 
 
@@ -78,3 +86,56 @@ Schema *Schema::find_implied(THD *thd)
     return &maxdb_schema;
   return &mariadb_schema;
 }
+
+
+Item *Schema::make_item_func_replace(THD *thd,
+                                     Item *subj,
+                                     Item *find,
+                                     Item *replace) const
+{
+  return new (thd->mem_root) Item_func_replace(thd, subj, find, replace);
+}
+
+
+Item *Schema::make_item_func_substr(THD *thd,
+                                    const Lex_substring_spec_st &spec) const
+{
+  return spec.m_for ?
+    new (thd->mem_root) Item_func_substr(thd, spec.m_subject, spec.m_from,
+                                              spec.m_for) :
+    new (thd->mem_root) Item_func_substr(thd, spec.m_subject, spec.m_from);
+}
+
+
+Item *Schema::make_item_func_trim(THD *thd, const Lex_trim_st &spec) const
+{
+  return spec.make_item_func_trim_std(thd);
+}
+
+
+Item *Schema_oracle::make_item_func_replace(THD *thd,
+                                            Item *subj,
+                                            Item *find,
+                                            Item *replace) const
+{
+  return new (thd->mem_root) Item_func_replace_oracle(thd, subj, find, replace);
+}
+
+
+Item *Schema_oracle::make_item_func_substr(THD *thd,
+                                    const Lex_substring_spec_st &spec) const
+{
+  return spec.m_for ?
+    new (thd->mem_root) Item_func_substr_oracle(thd, spec.m_subject,
+                                                     spec.m_from,
+                                                     spec.m_for) :
+    new (thd->mem_root) Item_func_substr_oracle(thd, spec.m_subject,
+                                                     spec.m_from);
+}
+
+
+Item *Schema_oracle::make_item_func_trim(THD *thd,
+                                         const Lex_trim_st &spec) const
+{
+  return spec.make_item_func_trim_oracle(thd);
+}

sql/sql_schema.h

@@ -33,6 +33,17 @@ public:
   {
     return src;
   }
+
+  // Builders for native SQL function with a special syntax in sql_yacc.yy
+  virtual Item *make_item_func_replace(THD *thd,
+                                       Item *subj,
+                                       Item *find,
+                                       Item *replace) const;
+  virtual Item *make_item_func_substr(THD *thd,
+                                      const Lex_substring_spec_st &spec) const;
+
+  virtual Item *make_item_func_trim(THD *thd, const Lex_trim_st &spec) const;
+
   /*
     For now we have *hard-coded* compatibility schemas:
       schema_mariadb, schema_oracle, schema_maxdb.

sql/sql_yacc.yy

@@ -718,6 +718,7 @@ Virtual_column_info *add_virtual_expression(THD *thd, Item *expr)
   Lex_for_loop_st for_loop;
   Lex_for_loop_bounds_st for_loop_bounds;
   Lex_trim_st trim;
+  Lex_substring_spec_st substring_spec;
   vers_history_point_t vers_history_point;
   struct
   {
@@ -1077,7 +1078,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  RELEASE_SYM                   /* SQL-2003-R */
 %token  RENAME
 %token  REPEAT_SYM                    /* MYSQL-FUNC */
-%token  REPLACE                       /* MYSQL-FUNC */
 %token  REQUIRE_SYM
 %token  RESIGNAL_SYM                  /* SQL-2003-R */
 %token  RESTRICT
@@ -1117,7 +1117,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  STDDEV_SAMP_SYM               /* SQL-2003-N */
 %token  STD_SYM
 %token  STRAIGHT_JOIN
-%token  SUBSTRING                     /* SQL-2003-N */
 %token  SUM_SYM                       /* SQL-2003-N */
 %token  SYSDATE
 %token  TABLE_REF_PRIORITY
@@ -1131,7 +1130,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  TO_SYM                        /* SQL-2003-R */
 %token  TRAILING                      /* SQL-2003-R */
 %token  TRIGGER_SYM                   /* SQL-2003-R */
-%token  TRIM                          /* SQL-2003-N */
 %token  TRUE_SYM                      /* SQL-2003-R */
 %token  ULONGLONG_NUM
 %token  UNDERSCORE_CHARSET
@@ -1182,6 +1180,14 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  <kwd>  RAISE_MARIADB_SYM             // PLSQL-R
 %token  <kwd>  ROWTYPE_MARIADB_SYM           // PLSQL-R
 
+/*
+  SQL functions with a special syntax
+*/
+%token  <kwd> REPLACE                        /* MYSQL-FUNC */
+%token  <kwd> SUBSTRING                      /* SQL-2003-N */
+%token  <kwd> TRIM                           /* SQL-2003-N */
+
+
 /*
   Non-reserved keywords
 */
@@ -2172,6 +2178,7 @@ END_OF_INPUT
 %type <for_loop> sp_for_loop_index_and_bounds
 %type <for_loop_bounds> sp_for_loop_bounds
 %type <trim> trim_operands
+%type <substring_spec> substring_operands
 %type <num> opt_sp_for_loop_direction
 %type <spvar_mode> sp_opt_inout
 %type <index_hint> index_hint_type
@@ -10916,7 +10923,8 @@ function_call_keyword:
           }
         | TRIM '(' trim_operands ')'
           {
-            if (unlikely(!($$= $3.make_item_func_trim(thd))))
+            if (unlikely(!($$= Schema::find_implied(thd)->
+                                 make_item_func_trim(thd, $3))))
               MYSQL_YYABORT;
           }
         | USER_SYM '(' ')'
@@ -10935,6 +10943,26 @@ function_call_keyword:
           }
         ;
 
+substring_operands:
+          expr ',' expr ',' expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3, $5);
+          }
+        | expr ',' expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3);
+          }
+        | expr FROM expr FOR_SYM expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3, $5);
+          }
+        | expr FROM expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3);
+          }
+        ;
+
+
 /*
   Function calls using non reserved keywords, with special syntaxic forms.
   Dedicated grammar rules are needed because of the syntax,
@@ -11049,24 +11077,10 @@ function_call_nonkeyword:
             if (unlikely($$ == NULL))
               MYSQL_YYABORT;
           }
-        | SUBSTRING '(' expr ',' expr ',' expr ')'
+        | SUBSTRING '(' substring_operands ')'
           {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5, $7))))
+            if (unlikely(!($$= Schema::find_implied(thd)->
-              MYSQL_YYABORT;
+                                 make_item_func_substr(thd, $3))))
-          }
-        | SUBSTRING '(' expr ',' expr ')'
-          {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5))))
-              MYSQL_YYABORT;
-          }
-        | SUBSTRING '(' expr FROM expr FOR_SYM expr ')'
-          {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5, $7))))
-              MYSQL_YYABORT;
-          }
-        | SUBSTRING '(' expr FROM expr ')'
-          {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5))))
               MYSQL_YYABORT;
           }
         | SYSDATE opt_time_precision
@@ -11282,7 +11296,8 @@ function_call_conflict:
           }
         | REPLACE '(' expr ',' expr ',' expr ')'
           {
-            if (unlikely(!($$= Lex->make_item_func_replace(thd, $3, $5, $7))))
+            if (unlikely(!($$= Schema::find_implied(thd)->
+                                 make_item_func_replace(thd, $3, $5, $7))))
               MYSQL_YYABORT;
           }
         | REVERSE_SYM '(' expr ')'

sql/sql_yacc_ora.yy

@@ -196,6 +196,7 @@ void ORAerror(THD *thd, const char *s)
   Lex_for_loop_st for_loop;
   Lex_for_loop_bounds_st for_loop_bounds;
   Lex_trim_st trim;
+  Lex_substring_spec_st substring_spec;
   vers_history_point_t vers_history_point;
   struct
   {
@@ -553,7 +554,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  RELEASE_SYM                   /* SQL-2003-R */
 %token  RENAME
 %token  REPEAT_SYM                    /* MYSQL-FUNC */
-%token  REPLACE                       /* MYSQL-FUNC */
 %token  REQUIRE_SYM
 %token  RESIGNAL_SYM                  /* SQL-2003-R */
 %token  RESTRICT
@@ -593,7 +593,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  STDDEV_SAMP_SYM               /* SQL-2003-N */
 %token  STD_SYM
 %token  STRAIGHT_JOIN
-%token  SUBSTRING                     /* SQL-2003-N */
 %token  SUM_SYM                       /* SQL-2003-N */
 %token  SYSDATE
 %token  TABLE_REF_PRIORITY
@@ -607,7 +606,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  TO_SYM                        /* SQL-2003-R */
 %token  TRAILING                      /* SQL-2003-R */
 %token  TRIGGER_SYM                   /* SQL-2003-R */
-%token  TRIM                          /* SQL-2003-N */
 %token  TRUE_SYM                      /* SQL-2003-R */
 %token  ULONGLONG_NUM
 %token  UNDERSCORE_CHARSET
@@ -658,6 +656,14 @@ bool my_yyoverflow(short **a, YYSTYPE **b, size_t *yystacksize);
 %token  <kwd>  RAISE_MARIADB_SYM             // PLSQL-R
 %token  <kwd>  ROWTYPE_MARIADB_SYM           // PLSQL-R
 
+/*
+  SQL functions with a special syntax
+*/
+%token  <kwd> REPLACE                        /* MYSQL-FUNC */
+%token  <kwd> SUBSTRING                      /* SQL-2003-N */
+%token  <kwd> TRIM                           /* SQL-2003-N */
+
+
 /*
   Non-reserved keywords
 */
@@ -1673,6 +1679,7 @@ END_OF_INPUT
 %type <for_loop> sp_for_loop_index_and_bounds
 %type <for_loop_bounds> sp_for_loop_bounds
 %type <trim> trim_operands
+%type <substring_spec> substring_operands
 %type <num> opt_sp_for_loop_direction
 %type <spvar_mode> sp_opt_inout
 %type <index_hint> index_hint_type
@@ -11031,7 +11038,8 @@ function_call_keyword:
           }
         | TRIM '(' trim_operands ')'
           {
-            if (unlikely(!($$= $3.make_item_func_trim(thd))))
+            if (unlikely(!($$= Schema::find_implied(thd)->
+                                 make_item_func_trim(thd, $3))))
               MYSQL_YYABORT;
           }
         | USER_SYM '(' ')'
@@ -11050,6 +11058,26 @@ function_call_keyword:
           }
         ;
 
+substring_operands:
+          expr ',' expr ',' expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3, $5);
+          }
+        | expr ',' expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3);
+          }
+        | expr FROM expr FOR_SYM expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3, $5);
+          }
+        | expr FROM expr
+          {
+            $$= Lex_substring_spec_st::init($1, $3);
+          }
+        ;
+
+
 /*
   Function calls using non reserved keywords, with special syntaxic forms.
   Dedicated grammar rules are needed because of the syntax,
@@ -11164,24 +11192,10 @@ function_call_nonkeyword:
             if (unlikely($$ == NULL))
               MYSQL_YYABORT;
           }
-        | SUBSTRING '(' expr ',' expr ',' expr ')'
+        | SUBSTRING '(' substring_operands ')'
           {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5, $7))))
+            if (unlikely(!($$= Schema::find_implied(thd)->
-              MYSQL_YYABORT;
+                                 make_item_func_substr(thd, $3))))
-          }
-        | SUBSTRING '(' expr ',' expr ')'
-          {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5))))
-              MYSQL_YYABORT;
-          }
-        | SUBSTRING '(' expr FROM expr FOR_SYM expr ')'
-          {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5, $7))))
-              MYSQL_YYABORT;
-          }
-        | SUBSTRING '(' expr FROM expr ')'
-          {
-            if (unlikely(!($$= Lex->make_item_func_substr(thd, $3, $5))))
               MYSQL_YYABORT;
           }
         | SYSDATE opt_time_precision
@@ -11397,7 +11411,8 @@ function_call_conflict:
           }
         | REPLACE '(' expr ',' expr ',' expr ')'
           {
-            if (unlikely(!($$= Lex->make_item_func_replace(thd, $3, $5, $7))))
+            if (unlikely(!($$= Schema::find_implied(thd)->
+                                 make_item_func_replace(thd, $3, $5, $7))))
               MYSQL_YYABORT;
           }
         | REVERSE_SYM '(' expr ')'

sql/structs.h

@@ -779,6 +779,11 @@ public:
   }
   Item *make_item_func_trim_std(THD *thd) const;
   Item *make_item_func_trim_oracle(THD *thd) const;
+  /*
+    This method is still used to handle LTRIM and RTRIM,
+    while the special syntax TRIM(... BOTH|LEADING|TRAILING)
+    is now handled by Schema::make_item_func_trim().
+  */
   Item *make_item_func_trim(THD *thd) const;
 };
 
@@ -790,6 +795,25 @@ public:
 };
 
 
+class Lex_substring_spec_st
+{
+public:
+  Item *m_subject;
+  Item *m_from;
+  Item *m_for;
+  static Lex_substring_spec_st init(Item *subject,
+                                    Item *from,
+                                    Item *xfor= NULL)
+  {
+    Lex_substring_spec_st res;
+    res.m_subject= subject;
+    res.m_from= from;
+    res.m_for= xfor;
+    return res;
+  }
+};
+
+
 class st_select_lex;
 
 class Lex_select_lock