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	|  10c063f9f0 Fixing the code adding MySQL _0900_ collations as _uca1400_ aliases
not to perform deep initialization of the corresponding _uca1400_
collations.
Only basic initialization is now performed which allows to watch
these collations (both _0900_ and _uca1400_) in queries to
INFORMATION_SCHEMA tables COLLATIONS and
COLLATION_CHARACTER_SET_APPLICABILITY,
as well as in SHOW COLLATION statements.
Deep initialization is now performed only when a collation
(either the _0900_ alias or the corresponding  _uca1400_ collation)
is used for the very first time after the server startup.
Refactoring was done to maintain the code easier:
- most of the _uca1400_ code was moved from ctype-uca.c
  to a new file ctype-uca1400.c
- most of the _0900_ code was moved from type-uca.c
  to a new file ctype-uca0900.c
Change details:
- The original function add_alias_for_collation() added by the patch for
   "MDEV-20912 Add support for utf8mb4_0900_* collations in MariaDB Server"
  was removed from mysys/charset.c, as it had two two problems:
  a. it forced deep initialization of the _uca1400_ collations
     when adding _0900_ aliases for them at the server startup
     (the main reported problem)
  b. the collation initialization code in add_alias_for_collation()
     was related more to collations rather than to memory management,
     so /strings should be a better place for it than /mysys.
  The code from add_alias_for_collation() was split into separate functions.
  Cyclic dependency was removed. `#include <my_sys.h>` was removed
  from /strings/ctype-uca.c. Collations are now added using a callback
  function MY_CHARSET_LOADED::add_collation, like it is done for
  user collations defined in Index.xml. The code in /mysys sets
  MY_CHARSET_LOADED::add_collation to add_compiled_collation().
- The function compare_collations() was removed.
  A new virtual function was added into my_collation_handler_st instead:
    my_bool (*eq_collation)(CHARSET_INFO *self, CHARSET_INFO *other);
  because it is the collation handler who knows how to detect equal
  collations by comparing only some of CHARSET_INFO members without
  their deep initialization.
  Three implementations were added:
  - my_ci_eq_collation_uca() for UCA collations, it compares
    _0900_ collations as equal to their corresponding _uca1400_ collations.
  - my_ci_eq_collation_utf8mb4_bin(), it compares
    utf8mb4_nopad_bin and utf8mb4_0900_bin as equal.
  - my_ci_eq_collation_generic() - the default implementation,
    which compares all collations as not equal.
  A C++ wrapper CHARSET_INFO::eq_collations() was added.
  The code in /sql was changes to use the wrapper instead of
  the former calls for the removed function compare_collations().
- A part of add_alias_for_collation() was moved into a new function
  my_ci_alloc(). It allocates a memory for a new charset_info_st
  instance together with the collation name and the comment using a single
  MY_CHARSET_LOADER::once_alloc call, which points to my_once_alloc()
  in the server.
- A part of add_alias_for_collation() was moved into a new function
  my_ci_make_comment_for_alias(). It makes an "Alias for xxx" string,
  e.g. "Alias for utf8mb4_uca1400_swedish_ai_ci" in case of
  utf8mb4_sv_0900_ai_ci.
- A part of the code in create_tailoring() was moved to
  a new function my_uca1400_collation_get_initialized_shared_uca(),
  to reuse the code between _uca1400_ and _0900_ collations.
- A new function my_collation_id_is_mysql_uca0900() was added
  in addition to my_collation_id_is_mysql_uca1400().
- Functions to build collation names were added:
   my_uca0900_collation_build_name()
   my_uca1400_collation_build_name()
- A shared function function was added:
  my_bool
  my_uca1400_collation_alloc_and_init(MY_CHARSET_LOADER *loader,
                                      LEX_CSTRING name,
                                      LEX_CSTRING comment,
                                      const uca_collation_def_param_t *param,
                                      uint id)
  It's reused to add _uca1400_ and _0900_ collations, with basic
  initialization (without deep initialization).
- The function add_compiled_collation() changed its return type from
  void to int, to make it compatible with MY_CHARSET_LOADER::add_collation.
- Functions mysql_uca0900_collation_definition_add(),
  mysql_uca0900_utf8mb4_collation_definitions_add(),
  mysql_utf8mb4_0900_bin_add() were added into ctype-uca0900.c.
  They get MY_CHARSET_LOADER as a parameter.
- Functions my_uca1400_collation_definition_add(),
  my_uca1400_collation_definitions_add() were moved from
  charset-def.c to strings/ctype-uca1400.c.
  The latter now accepts MY_CHARSET_LOADER as the first parameter
  instead of initializing a MY_CHARSET_LOADER inside.
- init_compiled_charsets() now initializes a MY_CHARSET_LOADER
  variable and passes it to all functions adding collations:
  - mysql_utf8mb4_0900_collation_definitions_add()
  - mysql_uca0900_utf8mb4_collation_definitions_add()
  - mysql_utf8mb4_0900_bin_add()
- A new structure was added into ctype-uca.h:
  typedef struct uca_collation_def_param
  {
    my_cs_encoding_t cs_id;
    uint tailoring_id;
    uint nopad_flags;
    uint level_flags;
  } uca_collation_def_param_t;
  It simplifies reusing the code for _uca1400_ and _0900_ collations.
- The definition of MY_UCA1400_COLLATION_DEFINITION was
  moved from ctype-uca.c to ctype-uca1400.h, to reuse
  the code for _uca1400_ and _0900_ collations.
- The definitions of "MY_UCA_INFO my_uca_v1400" and
  "MY_UCA_INFO my_uca1400_info_tailored[][]" were moved from
  ctype-uca.c to ctype-uca1400.c.
- The definitions/declarations of:
  - mysql_0900_collation_start,
  - struct mysql_0900_to_mariadb_1400_mapping
  - mysql_0900_to_mariadb_1400_mapping
  - mysql_utf8mb4_0900_collation_definitions_add()
  were moved from ctype-uca.c to ctype-uca0900.c
- Functions
  my_uca1400_make_builtin_collation_id()
  my_uca1400_collation_definition_init()
  my_uca1400_collation_id_uca400_compat()
  my_ci_get_collation_name_uca1400_context()
  were moved from ctype-uca.c to ctype-uca1400.c and ctype-uca1400.h
- A part of my_uca1400_collation_definition_init()
  was moved into my_uca0520_builtin_collation_by_id(),
  to make functions smaller. | ||
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| .. | ||
| atomic | ||
| mysql | ||
| providers | ||
| aligned.h | ||
| aria_backup.h | ||
| assume_aligned.h | ||
| big_endian.h | ||
| byte_order_generic.h | ||
| byte_order_generic_x86.h | ||
| byte_order_generic_x86_64.h | ||
| CMakeLists.txt | ||
| decimal.h | ||
| dur_prop.h | ||
| errmsg.h | ||
| ft_global.h | ||
| handler_ername.h | ||
| handler_state.h | ||
| hash.h | ||
| heap.h | ||
| ilist.h | ||
| json_lib.h | ||
| keycache.h | ||
| lf.h | ||
| little_endian.h | ||
| m_ctype.h | ||
| m_string.h | ||
| ma_dyncol.h | ||
| maria.h | ||
| mariadb_capi_rename.h | ||
| my_alloc.h | ||
| my_alloca.h | ||
| my_atomic.h | ||
| my_atomic_wrapper.h | ||
| my_attribute.h | ||
| my_base.h | ||
| my_bit.h | ||
| my_bitmap.h | ||
| my_byteorder.h | ||
| my_check_opt.h | ||
| my_cmp.h | ||
| my_compare.h | ||
| my_compiler.h | ||
| my_counter.h | ||
| my_cpu.h | ||
| my_crypt.h | ||
| my_dbug.h | ||
| my_decimal_limits.h | ||
| my_default.h | ||
| my_dir.h | ||
| my_getopt.h | ||
| my_global.h | ||
| my_handler_errors.h | ||
| my_libwrap.h | ||
| my_list.h | ||
| my_md5.h | ||
| my_minidump.h | ||
| my_net.h | ||
| my_nosys.h | ||
| my_pthread.h | ||
| my_rdtsc.h | ||
| my_rnd.h | ||
| my_service_manager.h | ||
| my_stack_alloc.h | ||
| my_stacktrace.h | ||
| my_sys.h | ||
| my_time.h | ||
| my_tracker.h | ||
| my_tree.h | ||
| my_uctype.h | ||
| my_user.h | ||
| my_valgrind.h | ||
| my_virtual_mem.h | ||
| my_xml.h | ||
| myisam.h | ||
| myisamchk.h | ||
| myisammrg.h | ||
| myisampack.h | ||
| mysql.h | ||
| mysql_com.h | ||
| mysql_com_server.h | ||
| mysql_embed.h | ||
| mysql_time.h | ||
| mysql_version.h.in | ||
| mysqld_default_groups.h | ||
| mysys_err.h | ||
| no_valgrind_without_big.inc | ||
| pack.h | ||
| password.h | ||
| pfs_file_provider.h | ||
| pfs_idle_provider.h | ||
| pfs_memory_provider.h | ||
| pfs_metadata_provider.h | ||
| pfs_socket_provider.h | ||
| pfs_stage_provider.h | ||
| pfs_statement_provider.h | ||
| pfs_table_provider.h | ||
| pfs_thread_provider.h | ||
| pfs_transaction_provider.h | ||
| probes_mysql.d.base | ||
| probes_mysql.h | ||
| probes_mysql_nodtrace.h.in | ||
| queues.h | ||
| rijndael.h | ||
| scope.h | ||
| service_versions.h | ||
| source_revision.h.in | ||
| span.h | ||
| sql_common.h | ||
| ssl_compat.h | ||
| sslopt-case.h | ||
| sslopt-longopts.h | ||
| sslopt-vars.h | ||
| t_ctype.h | ||
| thr_lock.h | ||
| thr_timer.h | ||
| typelib.h | ||
| violite.h | ||
| waiting_threads.h | ||
| welcome_copyright_notice.h | ||
| wqueue.h | ||
| wsrep.h | ||