Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 665 insertions, 0 deletions

diff --git a/sql/sql_base.h b/sql/sql_base.h
new file mode 100644
index 00000000..79f54dfe
--- /dev/null
+++ b/sql/sql_base.h
@@ -0,0 +1,665 @@
+/* Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2011, 2018, MariaDB
+
+
+   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 SQL_BASE_INCLUDED
+#define SQL_BASE_INCLUDED
+
+#include "sql_class.h"                          /* enum_column_usage */
+#include "sql_trigger.h"                        /* trg_event_type */
+#include "mysqld.h"                             /* key_map */
+#include "table_cache.h"
+
+class Item_ident;
+struct Name_resolution_context;
+class Open_table_context;
+class Open_tables_state;
+class Prelocking_strategy;
+struct TABLE_LIST;
+class THD;
+struct handlerton;
+struct TABLE;
+
+typedef class st_select_lex SELECT_LEX;
+
+typedef struct st_lock_param_type ALTER_PARTITION_PARAM_TYPE;
+
+/*
+  This enumeration type is used only by the function find_item_in_list
+  to return the info on how an item has been resolved against a list
+  of possibly aliased items.
+  The item can be resolved:
+   - against an alias name of the list's element (RESOLVED_AGAINST_ALIAS)
+   - against non-aliased field name of the list  (RESOLVED_WITH_NO_ALIAS)
+   - against an aliased field name of the list   (RESOLVED_BEHIND_ALIAS)
+   - ignoring the alias name in cases when SQL requires to ignore aliases
+     (e.g. when the resolved field reference contains a table name or
+     when the resolved item is an expression)   (RESOLVED_IGNORING_ALIAS)
+*/
+enum enum_resolution_type {
+  NOT_RESOLVED=0,
+  RESOLVED_IGNORING_ALIAS,
+  RESOLVED_BEHIND_ALIAS,
+  RESOLVED_WITH_NO_ALIAS,
+  RESOLVED_AGAINST_ALIAS
+};
+
+/* Argument to flush_tables() of what to flush */
+enum flush_tables_type {
+  FLUSH_ALL,
+  FLUSH_NON_TRANS_TABLES,
+  FLUSH_SYS_TABLES
+};
+
+enum find_item_error_report_type {REPORT_ALL_ERRORS, REPORT_EXCEPT_NOT_FOUND,
+				  IGNORE_ERRORS, REPORT_EXCEPT_NON_UNIQUE,
+                                  IGNORE_EXCEPT_NON_UNIQUE};
+
+/* Flag bits for unique_table() */
+#define CHECK_DUP_ALLOW_DIFFERENT_ALIAS 1
+#define CHECK_DUP_FOR_CREATE 2
+#define CHECK_DUP_SKIP_TEMP_TABLE 4
+
+uint get_table_def_key(const TABLE_LIST *table_list, const char **key);
+TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type update,
+                   uint lock_flags);
+
+/* mysql_lock_tables() and open_table() flags bits */
+#define MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK      0x0001
+#define MYSQL_OPEN_IGNORE_FLUSH                 0x0002
+/* MYSQL_OPEN_TEMPORARY_ONLY (0x0004) is not used anymore. */
+#define MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY      0x0008
+#define MYSQL_LOCK_LOG_TABLE                    0x0010
+/**
+  Do not try to acquire a metadata lock on the table: we
+  already have one.
+*/
+#define MYSQL_OPEN_HAS_MDL_LOCK                 0x0020
+/**
+  If in locked tables mode, ignore the locked tables and get
+  a new instance of the table.
+*/
+#define MYSQL_OPEN_GET_NEW_TABLE                0x0040
+/* 0x0080 used to be MYSQL_OPEN_SKIP_TEMPORARY */
+/** Fail instead of waiting when conficting metadata lock is discovered. */
+#define MYSQL_OPEN_FAIL_ON_MDL_CONFLICT         0x0100
+/** Open tables using MDL_SHARED lock instead of one specified in parser. */
+#define MYSQL_OPEN_FORCE_SHARED_MDL             0x0200
+/**
+  Open tables using MDL_SHARED_HIGH_PRIO lock instead of one specified
+  in parser.
+*/
+#define MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL   0x0400
+/**
+  When opening or locking the table, use the maximum timeout
+  (LONG_TIMEOUT = 1 year) rather than the user-supplied timeout value.
+*/
+#define MYSQL_LOCK_IGNORE_TIMEOUT               0x0800
+/**
+  When acquiring "strong" (SNW, SNRW, X) metadata locks on tables to
+  be open do not acquire global and schema-scope IX locks.
+*/
+#define MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK         0x1000
+#define MYSQL_LOCK_NOT_TEMPORARY		0x2000
+#define MYSQL_LOCK_USE_MALLOC                   0x4000
+/**
+  Only check THD::killed if waits happen (e.g. wait on MDL, wait on
+  table flush, wait on thr_lock.c locks) while opening and locking table.
+*/
+#define MYSQL_OPEN_IGNORE_KILLED                0x8000
+/**
+   Don't try to  auto-repair table
+*/
+#define MYSQL_OPEN_IGNORE_REPAIR                0x10000
+
+/**
+   Don't call decide_logging_format. Used for statistic tables etc
+*/
+#define MYSQL_OPEN_IGNORE_LOGGING_FORMAT        0x20000
+
+/** Please refer to the internals manual. */
+#define MYSQL_OPEN_REOPEN  (MYSQL_OPEN_IGNORE_FLUSH |\
+                            MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK |\
+                            MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY |\
+                            MYSQL_LOCK_IGNORE_TIMEOUT |\
+                            MYSQL_OPEN_GET_NEW_TABLE |\
+                            MYSQL_OPEN_HAS_MDL_LOCK)
+
+bool is_locked_view(THD *thd, TABLE_LIST *t);
+bool open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx);
+
+bool get_key_map_from_key_list(key_map *map, TABLE *table,
+                               List<String> *index_list);
+TABLE *find_locked_table(TABLE *list, const char *db, const char *table_name);
+TABLE *find_write_locked_table(TABLE *list, const char *db,
+                               const char *table_name);
+thr_lock_type read_lock_type_for_table(THD *thd,
+                                       Query_tables_list *prelocking_ctx,
+                                       TABLE_LIST *table_list,
+                                       bool routine_modifies_data);
+
+my_bool mysql_rm_tmp_tables(void);
+void close_tables_for_reopen(THD *thd, TABLE_LIST **tables,
+                             const MDL_savepoint &start_of_statement_svp);
+bool table_already_fk_prelocked(TABLE_LIST *tl, LEX_CSTRING *db,
+                                LEX_CSTRING *table, thr_lock_type lock_type);
+TABLE_LIST *find_table_in_list(TABLE_LIST *table,
+                               TABLE_LIST *TABLE_LIST::*link,
+                               const LEX_CSTRING *db_name,
+                               const LEX_CSTRING *table_name);
+int close_thread_tables(THD *thd);
+void switch_to_nullable_trigger_fields(List<Item> &items, TABLE *);
+void switch_defaults_to_nullable_trigger_fields(TABLE *table);
+bool fill_record_n_invoke_before_triggers(THD *thd, TABLE *table,
+                                          List<Item> &fields,
+                                          List<Item> &values,
+                                          bool ignore_errors,
+                                          enum trg_event_type event);
+bool fill_record_n_invoke_before_triggers(THD *thd, TABLE *table,
+                                          Field **field,
+                                          List<Item> &values,
+                                          bool ignore_errors,
+                                          enum trg_event_type event);
+bool insert_fields(THD *thd, Name_resolution_context *context,
+		   const char *db_name, const char *table_name,
+                   List_iterator<Item> *it, bool any_privileges,
+                   uint *hidden_bit_fields, bool returning_field);
+void make_leaves_list(THD *thd, List<TABLE_LIST> &list, TABLE_LIST *tables,
+                      bool full_table_list, TABLE_LIST *boundary);
+int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields,
+	       List<Item> *sum_func_list, SELECT_LEX *sl, bool returning_field);
+int setup_returning_fields(THD* thd, TABLE_LIST* table_list);
+bool setup_fields(THD *thd, Ref_ptr_array ref_pointer_array,
+                  List<Item> &item, enum_column_usage column_usage,
+                  List<Item> *sum_func_list, List<Item> *pre_fix,
+                  bool allow_sum_func);
+void unfix_fields(List<Item> &items);
+bool fill_record(THD * thd, TABLE *table_arg, List<Item> &fields,
+                 List<Item> &values, bool ignore_errors, bool update);
+bool fill_record(THD *thd, TABLE *table, Field **field, List<Item> &values,
+                 bool ignore_errors, bool use_value);
+
+Field *
+find_field_in_tables(THD *thd, Item_ident *item,
+                     TABLE_LIST *first_table, TABLE_LIST *last_table,
+                     Item **ref, find_item_error_report_type report_error,
+                     bool check_privileges, bool register_tree_change);
+Field *
+find_field_in_table_ref(THD *thd, TABLE_LIST *table_list,
+                        const char *name, size_t length,
+                        const char *item_name, const char *db_name,
+                        const char *table_name, Item **ref,
+                        bool check_privileges, bool allow_rowid,
+                        uint *cached_field_index_ptr,
+                        bool register_tree_change, TABLE_LIST **actual_table);
+Field *
+find_field_in_table(THD *thd, TABLE *table, const char *name, size_t length,
+                    bool allow_rowid, uint *cached_field_index_ptr);
+Field *
+find_field_in_table_sef(TABLE *table, const char *name);
+Item ** find_item_in_list(Item *item, List<Item> &items, uint *counter,
+                          find_item_error_report_type report_error,
+                          enum_resolution_type *resolution, uint limit= 0);
+bool setup_tables(THD *thd, Name_resolution_context *context,
+                  List<TABLE_LIST> *from_clause, TABLE_LIST *tables,
+                  List<TABLE_LIST> &leaves, bool select_insert,
+                  bool full_table_list);
+bool setup_tables_and_check_access(THD *thd,
+                                   Name_resolution_context *context,
+                                   List<TABLE_LIST> *from_clause,
+                                   TABLE_LIST *tables,
+                                   List<TABLE_LIST> &leaves, 
+                                   bool select_insert,
+                                   privilege_t want_access_first,
+                                   privilege_t want_access,
+                                   bool full_table_list);
+bool wait_while_table_is_used(THD *thd, TABLE *table,
+                              enum ha_extra_function function);
+
+void drop_open_table(THD *thd, TABLE *table, const LEX_CSTRING *db_name,
+                     const LEX_CSTRING *table_name);
+void update_non_unique_table_error(TABLE_LIST *update,
+                                   const char *operation,
+                                   TABLE_LIST *duplicate);
+int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves,
+		COND **conds);
+void wrap_ident(THD *thd, Item **conds);
+int setup_ftfuncs(SELECT_LEX* select);
+void cleanup_ftfuncs(SELECT_LEX *select_lex);
+int init_ftfuncs(THD *thd, SELECT_LEX* select, bool no_order);
+bool lock_table_names(THD *thd, const DDL_options_st &options,
+                      TABLE_LIST *table_list,
+                      TABLE_LIST *table_list_end, ulong lock_wait_timeout,
+                      uint flags);
+static inline bool
+lock_table_names(THD *thd, TABLE_LIST *table_list,
+                 TABLE_LIST *table_list_end, ulong lock_wait_timeout,
+                 uint flags)
+{
+  return lock_table_names(thd, thd->lex->create_info, table_list,
+                          table_list_end, lock_wait_timeout, flags);
+}
+bool open_tables(THD *thd, const DDL_options_st &options,
+                 TABLE_LIST **tables, uint *counter,
+                 uint flags, Prelocking_strategy *prelocking_strategy);
+
+static inline bool
+open_tables(THD *thd, TABLE_LIST **tables, uint *counter, uint flags,
+            Prelocking_strategy *prelocking_strategy)
+{
+  return open_tables(thd, thd->lex->create_info, tables, counter, flags,
+                     prelocking_strategy);
+}
+/* open_and_lock_tables with optional derived handling */
+bool open_and_lock_tables(THD *thd, const DDL_options_st &options,
+                          TABLE_LIST *tables,
+                          bool derived, uint flags,
+                          Prelocking_strategy *prelocking_strategy);
+static inline bool
+open_and_lock_tables(THD *thd, TABLE_LIST *tables,
+                     bool derived, uint flags,
+                     Prelocking_strategy *prelocking_strategy)
+{
+  return open_and_lock_tables(thd, thd->lex->create_info,
+                              tables, derived, flags, prelocking_strategy);
+}
+/* simple open_and_lock_tables without derived handling for single table */
+TABLE *open_n_lock_single_table(THD *thd, TABLE_LIST *table_l,
+                                thr_lock_type lock_type, uint flags,
+                                Prelocking_strategy *prelocking_strategy);
+bool open_normal_and_derived_tables(THD *thd, TABLE_LIST *tables, uint flags,
+                                    uint dt_phases);
+bool open_tables_only_view_structure(THD *thd, TABLE_LIST *tables,
+                                     bool can_deadlock);
+bool open_and_lock_internal_tables(TABLE *table, bool lock);
+bool lock_tables(THD *thd, TABLE_LIST *tables, uint counter, uint flags);
+int decide_logging_format(THD *thd, TABLE_LIST *tables);
+void close_thread_table(THD *thd, TABLE **table_ptr);
+TABLE_LIST *unique_table(THD *thd, TABLE_LIST *table, TABLE_LIST *table_list,
+                         uint check_flag);
+bool is_equal(const LEX_CSTRING *a, const LEX_CSTRING *b);
+
+class Open_tables_backup;
+/* Functions to work with system tables. */
+bool open_system_tables_for_read(THD *thd, TABLE_LIST *table_list);
+void close_system_tables(THD *thd);
+void close_mysql_tables(THD *thd);
+TABLE *open_system_table_for_update(THD *thd, TABLE_LIST *one_table);
+TABLE *open_log_table(THD *thd, TABLE_LIST *one_table, Open_tables_backup *backup);
+void close_log_table(THD *thd, Open_tables_backup *backup);
+
+bool close_cached_tables(THD *thd, TABLE_LIST *tables,
+                         bool wait_for_refresh, ulong timeout);
+void purge_tables();
+bool flush_tables(THD *thd, flush_tables_type flag);
+void close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
+                               ha_extra_function extra,
+                               TABLE *skip_table);
+OPEN_TABLE_LIST *list_open_tables(THD *thd, const char *db, const char *wild);
+bool tdc_open_view(THD *thd, TABLE_LIST *table_list, uint flags);
+
+TABLE *find_table_for_mdl_upgrade(THD *thd, const char *db,
+                                  const char *table_name,
+                                  int *p_error);
+void mark_tmp_table_for_reuse(TABLE *table);
+
+int dynamic_column_error_message(enum_dyncol_func_result rc);
+
+/* open_and_lock_tables with optional derived handling */
+int open_and_lock_tables_derived(THD *thd, TABLE_LIST *tables, bool derived);
+
+extern "C" int simple_raw_key_cmp(void* arg, const void* key1,
+                                  const void* key2);
+extern "C" int count_distinct_walk(void *elem, element_count count, void *arg);
+int simple_str_key_cmp(void* arg, uchar* key1, uchar* key2);
+
+extern Item **not_found_item;
+extern Field *not_found_field;
+extern Field *view_ref_found;
+
+/**
+  clean/setup table fields and map.
+
+  @param table        TABLE structure pointer (which should be setup)
+  @param table_list   TABLE_LIST structure pointer (owner of TABLE)
+  @param tablenr     table number
+*/
+
+
+inline void setup_table_map(TABLE *table, TABLE_LIST *table_list, uint tablenr)
+{
+  table->used_fields= 0;
+  table_list->reset_const_table();
+  table->null_row= 0;
+  table->status= STATUS_NO_RECORD;
+  table->maybe_null= table_list->outer_join;
+  TABLE_LIST *embedding= table_list->embedding;
+  while (!table->maybe_null && embedding)
+  {
+    table->maybe_null= embedding->outer_join;
+    embedding= embedding->embedding;
+  }
+  table->tablenr= tablenr;
+  table->map= (table_map) 1 << tablenr;
+  table->force_index= table_list->force_index;
+  table->force_index_order= table->force_index_group= 0;
+  table->covering_keys= table->s->keys_for_keyread;
+}
+
+inline TABLE_LIST *find_table_in_global_list(TABLE_LIST *table,
+                                             LEX_CSTRING *db_name,
+                                             LEX_CSTRING *table_name)
+{
+  return find_table_in_list(table, &TABLE_LIST::next_global,
+                            db_name, table_name);
+}
+
+inline bool setup_fields_with_no_wrap(THD *thd, Ref_ptr_array ref_pointer_array,
+                                      List<Item> &item,
+                                      enum_column_usage column_usage,
+                                      List<Item> *sum_func_list,
+                                      bool allow_sum_func)
+{
+  bool res;
+  SELECT_LEX *first= thd->lex->first_select_lex();
+  DBUG_ASSERT(thd->lex->current_select == first);
+  first->no_wrap_view_item= TRUE;
+  res= setup_fields(thd, ref_pointer_array, item, column_usage,
+                    sum_func_list, NULL,  allow_sum_func);
+  first->no_wrap_view_item= FALSE;
+  return res;
+}
+
+/**
+  An abstract class for a strategy specifying how the prelocking
+  algorithm should extend the prelocking set while processing
+  already existing elements in the set.
+*/
+
+class Prelocking_strategy
+{
+public:
+  virtual ~Prelocking_strategy() { }
+
+  virtual void reset(THD *thd) { };
+  virtual bool handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
+                              Sroutine_hash_entry *rt, sp_head *sp,
+                              bool *need_prelocking) = 0;
+  virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
+                            TABLE_LIST *table_list, bool *need_prelocking) = 0;
+  virtual bool handle_view(THD *thd, Query_tables_list *prelocking_ctx,
+                           TABLE_LIST *table_list, bool *need_prelocking)= 0;
+  virtual bool handle_end(THD *thd) { return 0; };
+};
+
+
+/**
+  A Strategy for prelocking algorithm suitable for DML statements.
+
+  Ensures that all tables used by all statement's SF/SP/triggers and
+  required for foreign key checks are prelocked and SF/SPs used are
+  cached.
+*/
+
+class DML_prelocking_strategy : public Prelocking_strategy
+{
+public:
+  virtual bool handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
+                              Sroutine_hash_entry *rt, sp_head *sp,
+                              bool *need_prelocking);
+  virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
+                            TABLE_LIST *table_list, bool *need_prelocking);
+  virtual bool handle_view(THD *thd, Query_tables_list *prelocking_ctx,
+                           TABLE_LIST *table_list, bool *need_prelocking);
+};
+
+
+/**
+  A strategy for prelocking algorithm to be used for LOCK TABLES
+  statement.
+*/
+
+class Lock_tables_prelocking_strategy : public DML_prelocking_strategy
+{
+  virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
+                            TABLE_LIST *table_list, bool *need_prelocking);
+};
+
+
+/**
+  Strategy for prelocking algorithm to be used for ALTER TABLE statements.
+
+  Unlike DML or LOCK TABLES strategy, it doesn't
+  prelock triggers, views or stored routines, since they are not
+  used during ALTER.
+*/
+
+class Alter_table_prelocking_strategy : public Prelocking_strategy
+{
+public:
+  virtual bool handle_routine(THD *thd, Query_tables_list *prelocking_ctx,
+                              Sroutine_hash_entry *rt, sp_head *sp,
+                              bool *need_prelocking);
+  virtual bool handle_table(THD *thd, Query_tables_list *prelocking_ctx,
+                            TABLE_LIST *table_list, bool *need_prelocking);
+  virtual bool handle_view(THD *thd, Query_tables_list *prelocking_ctx,
+                           TABLE_LIST *table_list, bool *need_prelocking);
+};
+
+
+inline bool
+open_tables(THD *thd, const DDL_options_st &options,
+            TABLE_LIST **tables, uint *counter, uint flags)
+{
+  DML_prelocking_strategy prelocking_strategy;
+
+  return open_tables(thd, options, tables, counter, flags,
+                     &prelocking_strategy);
+}
+inline bool
+open_tables(THD *thd, TABLE_LIST **tables, uint *counter, uint flags)
+{
+  DML_prelocking_strategy prelocking_strategy;
+
+  return open_tables(thd, thd->lex->create_info, tables, counter, flags,
+                     &prelocking_strategy);
+}
+
+inline TABLE *open_n_lock_single_table(THD *thd, TABLE_LIST *table_l,
+                                       thr_lock_type lock_type, uint flags)
+{
+  DML_prelocking_strategy prelocking_strategy;
+
+  return open_n_lock_single_table(thd, table_l, lock_type, flags,
+                                  &prelocking_strategy);
+}
+
+
+/* open_and_lock_tables with derived handling */
+inline bool open_and_lock_tables(THD *thd,
+                                 const DDL_options_st &options,
+                                 TABLE_LIST *tables,
+                                 bool derived, uint flags)
+{
+  DML_prelocking_strategy prelocking_strategy;
+
+  return open_and_lock_tables(thd, options, tables, derived, flags,
+                              &prelocking_strategy);
+}
+inline bool open_and_lock_tables(THD *thd, TABLE_LIST *tables,
+                                  bool derived, uint flags)
+{
+  DML_prelocking_strategy prelocking_strategy;
+
+  return open_and_lock_tables(thd, thd->lex->create_info,
+                              tables, derived, flags,
+                              &prelocking_strategy);
+}
+
+
+bool restart_trans_for_tables(THD *thd, TABLE_LIST *table);
+
+bool extend_table_list(THD *thd, TABLE_LIST *tables,
+                       Prelocking_strategy *prelocking_strategy,
+                       bool has_prelocking_list);
+
+void promote_select_describe_flag_if_needed(LEX *lex);
+
+/**
+  A context of open_tables() function, used to recover
+  from a failed open_table() or open_routine() attempt.
+*/
+
+class Open_table_context
+{
+public:
+  enum enum_open_table_action
+  {
+    OT_NO_ACTION= 0,
+    OT_BACKOFF_AND_RETRY,
+    OT_REOPEN_TABLES,
+    OT_DISCOVER,
+    OT_REPAIR
+  };
+  Open_table_context(THD *thd, uint flags);
+
+  bool recover_from_failed_open();
+  bool request_backoff_action(enum_open_table_action action_arg,
+                              TABLE_LIST *table);
+
+  bool can_recover_from_failed_open() const
+  { return m_action != OT_NO_ACTION; }
+
+  /**
+    When doing a back-off, we close all tables acquired by this
+    statement.  Return an MDL savepoint taken at the beginning of
+    the statement, so that we can rollback to it before waiting on
+    locks.
+  */
+  const MDL_savepoint &start_of_statement_svp() const
+  {
+    return m_start_of_statement_svp;
+  }
+
+  inline ulong get_timeout() const
+  {
+    return m_timeout;
+  }
+
+  uint get_flags() const { return m_flags; }
+
+  /**
+    Set flag indicating that we have already acquired metadata lock
+    protecting this statement against GRL while opening tables.
+  */
+  void set_has_protection_against_grl(enum_mdl_type mdl_type)
+  {
+    m_has_protection_against_grl|= MDL_BIT(mdl_type);
+  }
+
+  bool has_protection_against_grl(enum_mdl_type mdl_type) const
+  {
+    return (bool) (m_has_protection_against_grl & MDL_BIT(mdl_type));
+  }
+
+private:
+  /* THD for which tables are opened. */
+  THD *m_thd;
+  /**
+    For OT_DISCOVER and OT_REPAIR actions, the table list element for
+    the table which definition should be re-discovered or which
+    should be repaired.
+  */
+  TABLE_LIST *m_failed_table;
+  MDL_savepoint m_start_of_statement_svp;
+  /**
+    Lock timeout in seconds. Initialized to LONG_TIMEOUT when opening system
+    tables or to the "lock_wait_timeout" system variable for regular tables.
+  */
+  ulong m_timeout;
+  /* open_table() flags. */
+  uint m_flags;
+  /** Back off action. */
+  enum enum_open_table_action m_action;
+  /**
+    Whether we had any locks when this context was created.
+    If we did, they are from the previous statement of a transaction,
+    and we can't safely do back-off (and release them).
+  */
+  bool m_has_locks;
+  /**
+    Indicates that in the process of opening tables we have acquired
+    protection against global read lock.
+  */
+  mdl_bitmap_t m_has_protection_against_grl;
+};
+
+
+/**
+  Check if a TABLE_LIST instance represents a pre-opened temporary table.
+*/
+
+inline bool is_temporary_table(TABLE_LIST *tl)
+{
+  if (tl->view || tl->schema_table)
+    return FALSE;
+
+  if (!tl->table)
+    return FALSE;
+
+  /*
+    NOTE: 'table->s' might be NULL for specially constructed TABLE
+    instances. See SHOW TRIGGERS for example.
+  */
+
+  if (!tl->table->s)
+    return FALSE;
+
+  return tl->table->s->tmp_table != NO_TMP_TABLE;
+}
+
+
+/**
+  This internal handler is used to trap ER_NO_SUCH_TABLE.
+*/
+
+class No_such_table_error_handler : public Internal_error_handler
+{
+public:
+  No_such_table_error_handler()
+    : m_handled_errors(0), m_unhandled_errors(0)
+  {}
+
+  bool handle_condition(THD *thd,
+                        uint sql_errno,
+                        const char* sqlstate,
+                        Sql_condition::enum_warning_level *level,
+                        const char* msg,
+                        Sql_condition ** cond_hdl);
+
+  /**
+    Returns TRUE if one or more ER_NO_SUCH_TABLE errors have been
+    trapped and no other errors have been seen. FALSE otherwise.
+  */
+  bool safely_trapped_errors();
+
+private:
+  int m_handled_errors;
+  int m_unhandled_errors;
+};
+
+
+#endif /* SQL_BASE_INCLUDED */