MDEV-33281 Fix code review comments

mysql-test/main/lowercase_table.result

@@ -209,7 +209,7 @@ DROP PACKAGE test.pkg;
 # End of 11.4 tests
 #
 #
-# Start of 11.6 tests
+# Start of 11.7 tests
 #
 #
 # MDEV-33281 Implement optimizer hints like in MySQL
@@ -233,5 +233,5 @@ Warnings:
 Warning	4202	Hint BKA("A") is ignored as conflicting/duplicated
 DROP TABLE t1;
 #
-# End of 11.6 tests
+# End of 11.7 tests
 #

mysql-test/main/lowercase_table.test

@@ -208,7 +208,7 @@ DROP PACKAGE test.pkg;
 
 
 --echo #
---echo # Start of 11.6 tests
+--echo # Start of 11.7 tests
 --echo #
 
 --echo #
@@ -233,5 +233,5 @@ SELECT /*+BKA(a) BKA(A)*/ a.a FROM t1 a;
 DROP TABLE t1;
 
 --echo #
---echo # End of 11.6 tests
+--echo # End of 11.7 tests
 --echo #

mysql-test/main/lowercase_table5.result

@@ -190,7 +190,7 @@ DROP DATABASE MYSQL;
 # End of 10.5 tests
 #
 #
-# Start of 11.6 tests
+# Start of 11.7 tests
 #
 #
 # MDEV-33281 Implement optimizer hints like in MySQL
@@ -212,5 +212,5 @@ a	a
 2	2
 DROP TABLE t1;
 #
-# End of 11.6 tests
+# End of 11.7 tests
 #

mysql-test/main/lowercase_table5.test

@@ -189,7 +189,7 @@ DROP DATABASE MYSQL;
 --echo #
 
 --echo #
---echo # Start of 11.6 tests
+--echo # Start of 11.7 tests
 --echo #
 
 --echo #
@@ -212,5 +212,5 @@ SELECT /*+BKA(a) BKA(A)*/ a.a, A.a FROM t1 a, t1 A;
 DROP TABLE t1;
 
 --echo #
---echo # End of 11.6 tests
+--echo # End of 11.7 tests
 --echo #

sql/opt_hints.cc

@@ -34,12 +34,12 @@
 
 struct st_opt_hint_info opt_hint_info[]=
 {
-  {Lex_cstring_strlen("BKA"), true, true},
-  {Lex_cstring_strlen("BNL"), true, true},
-  {Lex_cstring_strlen("ICP"), true, true},
-  {Lex_cstring_strlen("MRR"), true, true},
-  {Lex_cstring_strlen("NO_RANGE_OPTIMIZATION"), true, true},
-  {Lex_cstring_strlen("QB_NAME"), false, false},
+  {{STRING_WITH_LEN("BKA")}, true, true},
+  {{STRING_WITH_LEN("BNL")}, true, true},
+  {{STRING_WITH_LEN("ICP")}, true, true},
+  {{STRING_WITH_LEN("MRR")}, true, true},
+  {{STRING_WITH_LEN("NO_RANGE_OPTIMIZATION")}, true, true},
+  {{STRING_WITH_LEN("QB_NAME")}, false, false},
   {null_clex_str, 0, 0}
 };
 
@@ -234,9 +234,9 @@ Opt_hints* Opt_hints::find_by_name(const LEX_CSTRING &name_arg) const
 {
   for (uint i= 0; i < child_array.size(); i++)
   {
-    const LEX_CSTRING *name= child_array[i]->get_name();
+    const LEX_CSTRING name= child_array[i]->get_name();
     CHARSET_INFO *cs= child_array[i]->charset_info();
-    if (name && !cs->strnncollsp(*name, name_arg))
+    if (name.str && !cs->strnncollsp(name, name_arg))
       return child_array[i];
   }
   return NULL;
@@ -356,7 +356,7 @@ void Opt_hints_table::adjust_key_hints(TABLE *table)
     KEY *key_info= table->key_info;
     for (uint j= 0 ; j < table->s->keys ; j++, key_info++)
     {
-      if (key_info->name.streq((*hint)->get_name()[0]))
+      if (key_info->name.streq((*hint)->get_name()))
       {
         (*hint)->set_resolved();
         keyinfo_array[j]= static_cast<Opt_hints_key *>(*hint);
@@ -666,7 +666,7 @@ bool Optimizer_hint_parser::Qb_name_hint::resolve(Parse_context *pc) const
 
   const Lex_ident_sys qb_name_sys= Query_block_name::to_ident_sys(pc->thd);
 
-  if (qb->get_name() ||                            // QB name is already set
+  if (qb->get_name().str ||                        // QB name is already set
       qb->get_parent()->find_by_name(qb_name_sys)) // Name is already used
   {
     print_warn(pc->thd, ER_WARN_CONFLICTING_HINT, QB_NAME_HINT_ENUM, true,

sql/opt_hints.h

@@ -139,6 +139,7 @@ class Opt_hints_key;
 
 class Opt_hints : public Sql_alloc
 {
+protected:
   /*
     Name of object referred by the hint.
     This name is empty for global level,
@@ -147,6 +148,7 @@ class Opt_hints : public Sql_alloc
     for key level.
   */
   Lex_ident_sys name;
+private:
   /*
     Parent object. There is no parent for global level,
     for query block level parent is Opt_hints_global object,
@@ -215,9 +217,9 @@ class Opt_hints : public Sql_alloc
     return Lex_ident_column::charset_info();
   }
 
-  virtual const LEX_CSTRING *get_name() const
+  const LEX_CSTRING get_name() const
   {
-    return name.str ? &name : nullptr;
+    return name;
   }
   void set_name(const Lex_ident_sys &name_arg) { name= name_arg; }
   Opt_hints *get_parent() const { return parent; }
@@ -326,10 +328,9 @@ class Opt_hints_qb : public Opt_hints
                MEM_ROOT *mem_root_arg,
                uint select_number_arg);
 
-  const LEX_CSTRING *get_print_name()
+  const LEX_CSTRING get_print_name()
   {
-    const LEX_CSTRING *str= Opt_hints::get_name();
-    return str ? str : &sys_name;
+    return name.str ? name : sys_name;
   }
 
   /**
@@ -340,10 +341,10 @@ class Opt_hints_qb : public Opt_hints
   */
   void append_qb_hint(THD *thd, String *str)
   {
-    if (get_name())
+    if (name.str)
     {
       str->append(STRING_WITH_LEN("QB_NAME("));
-      append_identifier(thd, str, get_name()->str, get_name()->length);
+      append_identifier(thd, str, &name);
       str->append(STRING_WITH_LEN(") "));
     }
   }
@@ -356,7 +357,8 @@ class Opt_hints_qb : public Opt_hints
   virtual void append_name(THD *thd, String *str) override
   {
     str->append(STRING_WITH_LEN("@"));
-    append_identifier(thd, str, get_print_name()->str, get_print_name()->length);
+    const LEX_CSTRING print_name= get_print_name();
+    append_identifier(thd, str, &print_name);
   }
 
   /**
@@ -405,7 +407,7 @@ class Opt_hints_table : public Opt_hints
   */
   virtual void append_name(THD *thd, String *str) override
   {
-    append_identifier(thd, str, get_name()->str, get_name()->length);
+    append_identifier(thd, str, &name);
     get_parent()->append_name(thd, str);
   }
   /**
@@ -447,7 +449,7 @@ class Opt_hints_key : public Opt_hints
   {
     get_parent()->append_name(thd, str);
     str->append(' ');
-    append_identifier(thd, str, get_name()->str, get_name()->length);
+    append_identifier(thd, str, &name);
   }
 
   virtual uint get_warn_unresolved_code() const override
@@ -505,14 +507,4 @@ bool hint_table_state(const THD *thd, const TABLE *table,
 bool hint_table_state_or_fallback(const THD *thd, const TABLE *table,
                                   opt_hints_enum type_arg,
                                   bool fallback_value);
-
-
-class Hints_string_buffer : public StringBuffer<64>
-{
-public:
-  Hints_string_buffer()
-   :StringBuffer(system_charset_info)
-  { }
-};
-
 #endif /* OPT_HINTS_INCLUDED */

sql/sql_select.cc

@@ -31665,10 +31665,10 @@ void st_select_lex::print_hints(THD *thd,
     // Some hints were printed, close the hint string
     str->append(STRING_WITH_LEN("*/ "));
   }
-  else 
+  else
   {
     // No hints were added, rollback the previouly added header
-    str->chop(header.length);
+    str->length(len_before_hints - header.length);
   }
 }
 

sql/sql_string.h

@@ -363,21 +363,6 @@ class Binary_string: public Sql_alloc
     }
   }
 
-  /*
-    Remove `num_of_chars` trailing characters from the string.
-    If `num_of_chars` is larger than the string length, the methods chops all
-    characters
-  */
-  void chop(uint32 num_of_chars)
-  {
-    if (num_of_chars < str_length)
-      str_length-= num_of_chars;
-    else
-      str_length= 0;
-    Ptr[str_length]= '\0';
-    DBUG_ASSERT(strlen(Ptr) == str_length);
-  }
-
   // Returns offset to substring or -1
   int strstr(const Binary_string &search, uint32 offset=0) const;
   int strstr(const char *search, uint32 search_length, uint32 offset=0) const;