MDEV-19861 Add intfastructure to have ENUM columns in INFORMATION_SCHEMA

mysql-test/suite/innodb_i_s/innodb_buffer_page.result

@@ -18,7 +18,7 @@ INNODB_BUFFER_PAGE	CREATE TEMPORARY TABLE `INNODB_BUFFER_PAGE` (
   `DATA_SIZE` bigint(21) unsigned NOT NULL DEFAULT 0,
   `COMPRESSED_SIZE` bigint(21) unsigned NOT NULL DEFAULT 0,
   `PAGE_STATE` varchar(64) DEFAULT NULL,
-  `IO_FIX` varchar(64) DEFAULT NULL,
+  `IO_FIX` enum('IO_NONE','IO_READ','IO_WRITE','IO_PIN') DEFAULT NULL,
   `IS_OLD` varchar(3) DEFAULT NULL,
   `FREE_PAGE_CLOCK` bigint(21) unsigned NOT NULL DEFAULT 0
 ) ENGINE=MEMORY DEFAULT CHARSET=utf8

sql/sql_i_s.h

@@ -60,9 +60,12 @@ class Type
   */
   uint m_char_length;
   uint m_unsigned_flag;
+  const Typelib *m_typelib;
 public:
-  Type(const Type_handler *th, uint length, uint unsigned_flag)
-   :m_type_handler(th), m_char_length(length), m_unsigned_flag(unsigned_flag)
+  Type(const Type_handler *th, uint length, uint unsigned_flag,
+       const Typelib *typelib= NULL)
+   :m_type_handler(th), m_char_length(length), m_unsigned_flag(unsigned_flag),
+    m_typelib(typelib)
   { }
   const Type_handler *type_handler() const { return m_type_handler; }
   uint char_length()      const { return m_char_length; }
@@ -74,6 +77,7 @@ class Type
     return m_char_length;
   }
   uint unsigned_flag()    const { return m_unsigned_flag; }
+  const Typelib *typelib() const { return m_typelib; }
 };
 } // namespace Show
 
@@ -116,6 +120,14 @@ class ST_FIELD_INFO: public Show::Type
 namespace Show
 {
 
+
+class Enum: public Type
+{
+public:
+  Enum(const Typelib *typelib) :Type(&type_handler_enum, 0, false, typelib) { }
+};
+
+
 class Blob: public Type
 {
 public:

sql/sql_type.cc

@@ -2347,6 +2347,28 @@ Field *Type_handler_set::make_conversion_table_field(TABLE *table,
 }
 
 
+Field *Type_handler_enum::make_schema_field(TABLE *table,
+                                            const Record_addr &addr,
+                                            const ST_FIELD_INFO &def,
+                                            bool show_field) const
+{
+  LEX_CSTRING name= def.name();
+  const Typelib *typelib= def.typelib();
+  DBUG_ASSERT(typelib);
+  /*
+    Assume I_S columns don't have non-ASCII characters in names.
+    If we eventually want to, Typelib::max_char_length() must be implemented.
+  */
+  return new (table->in_use->mem_root)
+         Field_enum(addr.ptr(), (uint32) typelib->max_octet_length(),
+                    addr.null_ptr(), addr.null_bit(),
+                    Field::NONE, &name,
+                    get_enum_pack_length(typelib->count),
+                    typelib, system_charset_info);
+
+}
+
+
 /*************************************************************************/
 
 bool Type_handler::

sql/sql_type.h

@@ -144,6 +144,54 @@ class Data_type_statistics
 };
 
 
+class Typelib: public TYPELIB
+{
+public:
+  Typelib(uint count, const char **type_names, unsigned int *type_lengths)
+  {
+    TYPELIB::count= count;
+    TYPELIB::name= "";
+    TYPELIB::type_names= type_names;
+    TYPELIB::type_lengths= type_lengths;
+  }
+  uint max_octet_length() const
+  {
+    uint max_length= 0;
+    for (uint i= 0; i < TYPELIB::count; i++)
+    {
+      const uint length= TYPELIB::type_lengths[i];
+      set_if_bigger(max_length, length);
+    }
+    return max_length;
+  }
+};
+
+
+template<uint sz>
+class TypelibBuffer: public Typelib
+{
+  const char *m_type_names[sz + 1];
+  unsigned int m_type_lengths[sz + 1];
+public:
+  TypelibBuffer(uint count, const LEX_CSTRING *values)
+   :Typelib(count, m_type_names, m_type_lengths)
+  {
+    DBUG_ASSERT(sz >= count);
+    for (uint i= 0; i <  count; i++)
+    {
+      DBUG_ASSERT(values[i].str != NULL);
+      m_type_names[i]= values[i].str;
+      m_type_lengths[i]= values[i].length;
+    }
+    m_type_names[sz]= NullS; // End marker
+    m_type_lengths[sz]= 0;   // End marker
+  }
+  TypelibBuffer(const LEX_CSTRING *values)
+   :TypelibBuffer(sz, values)
+  { }
+};
+
+
 class Native: public Binary_string
 {
 public:
@@ -6474,6 +6522,10 @@ class Type_handler_enum: public Type_handler_typelib
                                    const Bit_addr &bit,
                                    const Column_definition_attributes *attr,
                                    uint32 flags) const;
+  Field *make_schema_field(TABLE *table,
+                           const Record_addr &addr,
+                           const ST_FIELD_INFO &def,
+                           bool show_field) const;
 };
 
 

storage/innobase/handler/i_s.cc

@@ -3914,6 +3914,19 @@ UNIV_INTERN struct st_maria_plugin	i_s_innodb_buffer_stats =
         STRUCT_FLD(maturity, MariaDB_PLUGIN_MATURITY_STABLE),
 };
 
+
+static const LEX_CSTRING io_values[]=
+{
+  STRING_WITH_LEN("IO_NONE"),
+  STRING_WITH_LEN("IO_READ"),
+  STRING_WITH_LEN("IO_WRITE"),
+  STRING_WITH_LEN("IO_PIN")
+};
+
+
+static TypelibBuffer<4> io_values_typelib(io_values);
+
+
 namespace Show {
 /* Fields of the dynamic table INNODB_BUFFER_POOL_PAGE. */
 static ST_FIELD_INFO	i_s_innodb_buffer_page_fields_info[] =
@@ -3972,7 +3985,7 @@ static ST_FIELD_INFO	i_s_innodb_buffer_page_fields_info[] =
   Column("PAGE_STATE", Varchar(64), NULLABLE),
 
 #define IDX_BUFFER_PAGE_IO_FIX		16 + I_S_AHI
-  Column("IO_FIX", Varchar(64), NULLABLE),
+  Column("IO_FIX", Enum(&io_values_typelib), NULLABLE),
 
 #define IDX_BUFFER_PAGE_IS_OLD		17 + I_S_AHI
   Column("IS_OLD", Varchar(3), NULLABLE),