mariadb/sql/lex_charset.h

/* Copyright (c) 2021, 2022, MariaDB Corporation.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */

#ifndef LEX_CHARSET_INCLUDED
#define LEX_CHARSET_INCLUDED


/*
  An exact character set, e.g:
    CHARACTER SET latin1
*/
class Lex_exact_charset
{
  CHARSET_INFO *m_ci;
public:
  explicit Lex_exact_charset(CHARSET_INFO *ci)
   :m_ci(ci)
  {
    DBUG_ASSERT(m_ci);
    DBUG_ASSERT(m_ci->state & MY_CS_PRIMARY);
  }
  CHARSET_INFO *charset_info() const { return m_ci; }
  bool raise_if_not_equal(const Lex_exact_charset &rhs) const;
  bool raise_if_not_applicable(const class Lex_exact_collation &cl) const;
};


/*
  A contextually typed collation, e.g.:
    COLLATE DEFAULT
    CHAR(10) BINARY
*/
class Lex_context_collation
{
  CHARSET_INFO *m_ci;
public:
  explicit Lex_context_collation(CHARSET_INFO *ci)
   :m_ci(ci)
  {
    DBUG_ASSERT(ci);
  }
  CHARSET_INFO *charset_info() const { return m_ci; }
  bool is_contextually_typed_collate_default() const
  {
    return m_ci == &my_collation_contextually_typed_default;
  }
  bool is_contextually_typed_binary_style() const
  {
    return m_ci == &my_collation_contextually_typed_binary;
  }
  bool raise_if_not_equal(const Lex_context_collation &cl) const;
};


/*
  An exact collation, e.g.
    COLLATE latin1_swedish_ci
*/
class Lex_exact_collation
{
  CHARSET_INFO *m_ci;
public:
  explicit Lex_exact_collation(CHARSET_INFO *ci)
   :m_ci(ci)
  {
    DBUG_ASSERT(ci);
  }
  CHARSET_INFO *charset_info() const { return m_ci; }
  // EXACT + EXACT
  bool raise_if_not_equal(const Lex_exact_collation &cl) const;
  // EXACT + CONTEXT
  // CONTEXT + EXACT
  bool raise_if_conflicts_with_context_collation(const Lex_context_collation &,
                                                 bool reverse_order) const;
};


/*
  Parse time COLLATE clause:
    COLLATE colation_name
  The collation can be either exact or contextual:
    COLLATE latin1_bin
    COLLATE DEFAULT
*/
class Lex_extended_collation_st
{
public:
  enum Type
  {
    TYPE_EXACT,
    TYPE_CONTEXTUALLY_TYPED
  };
protected:
  CHARSET_INFO *m_ci;
  Type m_type;
public:
  void init(CHARSET_INFO *ci, Type type)
  {
    m_ci= ci;
    m_type= type;
  }
  CHARSET_INFO *charset_info() const { return m_ci; }
  Type type() const { return m_type; }
  void set_collate_default()
  {
    m_ci= &my_collation_contextually_typed_default;
    m_type= TYPE_CONTEXTUALLY_TYPED;
  }
  bool raise_if_conflicts_with_context_collation(const Lex_context_collation &)
                                                 const;
  bool merge_exact_charset(const Lex_exact_charset &rhs);
  bool merge_exact_collation(const Lex_exact_collation &rhs);
  bool merge(const Lex_extended_collation_st &rhs);
};


class Lex_extended_collation: public Lex_extended_collation_st
{
public:
  Lex_extended_collation(CHARSET_INFO *ci, Type type)
  {
    init(ci, type);
  }
  Lex_extended_collation(const Lex_exact_collation &rhs)
  {
    init(rhs.charset_info(), TYPE_EXACT);
  }
};


/*
  CHARACTER SET cs_exact [COLLATE cl_exact_or_context]
*/
class Lex_exact_charset_opt_extended_collate
{
  CHARSET_INFO *m_ci;
  bool m_with_collate;
public:
  Lex_exact_charset_opt_extended_collate(CHARSET_INFO *ci, bool with_collate)
   :m_ci(ci), m_with_collate(with_collate)
  {
    DBUG_ASSERT(m_ci);
    DBUG_ASSERT((m_ci->state & MY_CS_PRIMARY) || m_with_collate);
  }
  Lex_exact_charset_opt_extended_collate(const Lex_exact_charset &cs)
   :m_ci(cs.charset_info()), m_with_collate(false)
  {
    DBUG_ASSERT(m_ci);
    DBUG_ASSERT(m_ci->state & MY_CS_PRIMARY);
  }
  Lex_exact_charset_opt_extended_collate(const Lex_exact_collation &cl)
   :m_ci(cl.charset_info()), m_with_collate(true)
  {
    DBUG_ASSERT(m_ci);
  }
  bool with_collate() const { return m_with_collate; }
  CHARSET_INFO *find_bin_collation() const;
  CHARSET_INFO *find_default_collation() const;
  bool raise_if_not_applicable(const Lex_exact_collation &cl) const;
  /*
    Add another COLLATE clause (exact or context).
    So the full syntax looks like:
      CHARACTER SET cs [COLLATE cl] ... COLLATE cl2
  */
  bool merge_collation(const Lex_extended_collation_st &cl)
  {
    switch (cl.type()) {
    case Lex_extended_collation_st::TYPE_EXACT:
      return merge_exact_collation(Lex_exact_collation(cl.charset_info()));
    case Lex_extended_collation_st::TYPE_CONTEXTUALLY_TYPED:
      return merge_context_collation(Lex_context_collation(cl.charset_info()));
    }
    DBUG_ASSERT(0);
    return false;
  }
  /*
    Add a context collation:
      CHARACTER SET cs [COLLATE cl] ... COLLATE DEFAULT
  */
  bool merge_context_collation(const Lex_context_collation &cl);
  bool merge_context_collation_override(const Lex_context_collation &cl);
  /*
    Add an exact collation:
      CHARACTER SET cs [COLLATE cl] ... COLLATE latin1_bin
  */
  bool merge_exact_collation(const Lex_exact_collation &cl);
  Lex_exact_collation collation() const
  {
    return Lex_exact_collation(m_ci);
  }
  Lex_exact_charset charset() const
  {
    if ((m_ci->state & MY_CS_PRIMARY))
      return Lex_exact_charset(m_ci);
    return Lex_exact_charset(find_default_collation());
  }
};


/*
  Parse time character set and collation for:
    [CHARACTER SET cs_exact] [COLLATE cl_exact_or_context]

  Can be:

  1. Empty (not specified on the column level):
     CREATE TABLE t1 (a CHAR(10)) CHARACTER SET latin2;        -- (1a)
     CREATE TABLE t1 (a CHAR(10));                             -- (1b)

  2. Precisely typed:
     CREATE TABLE t1 (a CHAR(10) COLLATE latin1_bin);          -- (2a)
     CREATE TABLE t1 (
       a CHAR(10) CHARACTER SET latin1 COLLATE latin1_bin);    -- (2b)

  3. Contextually typed:
     CREATE TABLE t2 (a CHAR(10) BINARY) CHARACTER SET latin2; -- (3a)
     CREATE TABLE t2 (a CHAR(10) BINARY);                      -- (3b)
     CREATE TABLE t2 (a CHAR(10) COLLATE DEFAULT)
       CHARACER SET latin2 COLLATE latin2_bin;                 -- (3c)

  In case of an empty or a contextually typed collation,
  it is a subject to later resolution, when the context
  character set becomes known in the end of the CREATE statement:
  - either after the explicit table level CHARACTER SET, like in (1a,3a,3c)
  - or by the inhereted database level CHARACTER SET, like in (1b,3b)

  Resolution happens in Type_handler::Column_definition_prepare_stage1().
*/
struct Lex_exact_charset_extended_collation_attrs_st
{
public:
  enum Type
  {
    TYPE_EMPTY= 0,
    TYPE_CHARACTER_SET= 1,
    TYPE_COLLATE_EXACT= 2,
    TYPE_COLLATE_CONTEXTUALLY_TYPED= 3
  };

// Number of bits required to store enum Type values

#define LEX_CHARSET_COLLATION_TYPE_BITS 2
  static_assert(((1<<LEX_CHARSET_COLLATION_TYPE_BITS)-1) >=
                 TYPE_COLLATE_CONTEXTUALLY_TYPED,
                 "Lex_exact_charset_extended_collation_attrs_st::Type bits");

protected:
  CHARSET_INFO *m_ci;
  Type m_type;
protected:
  static Type type_from_lex_collation_type(Lex_extended_collation_st::Type type)
  {
    switch (type) {
    case Lex_extended_collation_st::TYPE_EXACT:
      return TYPE_COLLATE_EXACT;
    case Lex_extended_collation_st::TYPE_CONTEXTUALLY_TYPED:
      return TYPE_COLLATE_CONTEXTUALLY_TYPED;
    }
    DBUG_ASSERT(0);
    return TYPE_COLLATE_EXACT;
  }
public:
  void init()
  {
    m_ci= NULL;
    m_type= TYPE_EMPTY;
  }
  void init(CHARSET_INFO *cs, Type type)
  {
    DBUG_ASSERT(cs || type == TYPE_EMPTY);
    m_ci= cs;
    m_type= type;
  }
  void init(const Lex_exact_charset &cs)
  {
    m_ci= cs.charset_info();
    m_type= TYPE_CHARACTER_SET;
  }
  void init(const Lex_exact_collation &cs)
  {
    m_ci= cs.charset_info();
    m_type= TYPE_COLLATE_EXACT;
  }
  void init(const Lex_exact_charset_opt_extended_collate &cscl)
  {
    cscl.with_collate() ? init(cscl.collation()) :
                          init(cscl.charset());
  }
  bool is_empty() const
  {
    return m_type == TYPE_EMPTY;
  }
  void set_charset(CHARSET_INFO *cs)
  {
    DBUG_ASSERT(cs);
    m_ci= cs;
    m_type= TYPE_CHARACTER_SET;
  }
  bool set_charset_collate_default(CHARSET_INFO *cs)
  {
    DBUG_ASSERT(cs);
    if (!(cs= Lex_exact_charset_opt_extended_collate(cs, true).
                find_default_collation()))
      return true;
    m_ci= cs;
    m_type= TYPE_COLLATE_EXACT;
    return false;
  }
  bool set_charset_collate_binary(CHARSET_INFO *cs)
  {
    DBUG_ASSERT(cs);
    if (!(cs= Lex_exact_charset_opt_extended_collate(cs, true).
                find_bin_collation()))
      return true;
    m_ci= cs;
    m_type= TYPE_COLLATE_EXACT;
    return false;
  }
  void set_collate_default()
  {
    m_ci= &my_collation_contextually_typed_default;
    m_type= TYPE_COLLATE_CONTEXTUALLY_TYPED;
  }
  void set_contextually_typed_binary_style()
  {
    m_ci= &my_collation_contextually_typed_binary;
    m_type= TYPE_COLLATE_CONTEXTUALLY_TYPED;
  }
  bool is_contextually_typed_collate_default() const
  {
    return Lex_context_collation(m_ci).is_contextually_typed_collate_default();
  }
  CHARSET_INFO *charset_info() const
  {
    return m_ci;
  }
  Type type() const
  {
    return m_type;
  }
  bool is_contextually_typed_collation() const
  {
    return m_type == TYPE_COLLATE_CONTEXTUALLY_TYPED;
  }
  CHARSET_INFO *resolved_to_character_set(CHARSET_INFO *cs) const;
  /*
    Merge the column CHARACTER SET clause to:
    - an exact collation name
    - a contextually typed collation
    "this" corresponds to `CHARACTER SET xxx [BINARY]`
    "cl" corresponds to the COLLATE clause
  */
  bool merge_column_charset_clause_and_collate_clause(
                    const Lex_exact_charset_extended_collation_attrs_st &cl)
  {
    switch (cl.type()) {
    case TYPE_EMPTY:
      return false;
    case TYPE_COLLATE_EXACT:
      return merge_exact_collation(Lex_exact_collation(cl.charset_info()));
    case TYPE_COLLATE_CONTEXTUALLY_TYPED:
    case TYPE_CHARACTER_SET:
      break;
    }
    DBUG_ASSERT(0);
    return false;
  }
  /*
    This method is used in the "attribute_list" rule to merge two independent
    COLLATE clauses (not belonging to a CHARACTER SET clause).
    "BINARY" and "COLLATE DEFAULT" are not possible
    in an independent COLLATE clause in a column attribute.
  */
  bool merge_column_collate_clause_and_collate_clause(
                    const Lex_exact_charset_extended_collation_attrs_st &cl)
  {
    DBUG_ASSERT(m_type != TYPE_COLLATE_CONTEXTUALLY_TYPED);
    DBUG_ASSERT(m_type != TYPE_CHARACTER_SET);
    switch (cl.type()) {
    case TYPE_EMPTY:
      return false;
    case TYPE_COLLATE_EXACT:
      return merge_exact_collation(Lex_exact_collation(cl.charset_info()));
    case TYPE_COLLATE_CONTEXTUALLY_TYPED:
    case TYPE_CHARACTER_SET:
      break;
    }
    DBUG_ASSERT(0);
    return false;
  }
  bool merge_exact_charset(const Lex_exact_charset &cs);
  bool merge_exact_collation(const Lex_exact_collation &cl);
  bool merge_context_collation(const Lex_context_collation &cl);
  bool merge_collation(const Lex_extended_collation_st &cl);
};


class Lex_exact_charset_extended_collation_attrs:
                        public Lex_exact_charset_extended_collation_attrs_st
{
public:
  Lex_exact_charset_extended_collation_attrs()
  {
    init();
  }
  Lex_exact_charset_extended_collation_attrs(CHARSET_INFO *collation, Type type)
  {
    init(collation, type);
  }
  explicit
  Lex_exact_charset_extended_collation_attrs(const Lex_exact_charset &cs)
  {
    init(cs.charset_info(), TYPE_CHARACTER_SET);
  }
  explicit
  Lex_exact_charset_extended_collation_attrs(const Lex_exact_collation &cl)
  {
    init(cl.charset_info(), TYPE_COLLATE_EXACT);
  }
  explicit
  Lex_exact_charset_extended_collation_attrs(const Lex_context_collation &cl)
  {
    init(cl.charset_info(), TYPE_COLLATE_CONTEXTUALLY_TYPED);
  }
  explicit
  Lex_exact_charset_extended_collation_attrs(
                    const Lex_exact_charset_opt_extended_collate &cscl)
  {
    init(cscl);
  }
  explicit
  Lex_exact_charset_extended_collation_attrs(const Lex_extended_collation_st &cl)
  {
    init(cl.charset_info(), type_from_lex_collation_type(cl.type()));
  }
  static Lex_exact_charset_extended_collation_attrs national(bool bin_mod)
  {
    return bin_mod ?
      Lex_exact_charset_extended_collation_attrs(&my_charset_utf8mb3_bin,
                                                 TYPE_COLLATE_EXACT) :
      Lex_exact_charset_extended_collation_attrs(&my_charset_utf8mb3_general_ci,
                                                 TYPE_CHARACTER_SET);
  }
};


using Lex_column_charset_collation_attrs_st =
        Lex_exact_charset_extended_collation_attrs_st;

using Lex_column_charset_collation_attrs =
        Lex_exact_charset_extended_collation_attrs;


#endif // LEX_CHARSET_INCLUDED