diff options
Diffstat (limited to 'sql/sql_help.cc')
| -rw-r--r-- | sql/sql_help.cc | 344 |
1 files changed, 279 insertions, 65 deletions
diff --git a/sql/sql_help.cc b/sql/sql_help.cc index ce29846e2f8..f9932f11798 100644 --- a/sql/sql_help.cc +++ b/sql/sql_help.cc @@ -430,6 +430,46 @@ void get_all_items_for_category(THD *thd, TABLE *items, Field *pfname, DBUG_VOID_RETURN; } + +/** + Collect field names of HELP header that will be sent to a client + + @param thd Thread data object + @param[out] field_list List of fields whose metadata should be collected for + sending to client +*/ + +static void fill_answer_1_fields(THD *thd, List<Item> *field_list) +{ + MEM_ROOT *mem_root= thd->mem_root; + + field_list->push_back(new (mem_root) Item_empty_string(thd, "name", 64), + mem_root); + field_list->push_back(new (mem_root) Item_empty_string(thd, "description", + 1000), + mem_root); + field_list->push_back(new (mem_root) Item_empty_string(thd, "example", 1000), + mem_root); +} + + +/** + Send metadata of an answer on help request to a client + + @param protocol protocol for sending +*/ + +static bool send_answer_1_metadata(Protocol *protocol) +{ + List<Item> field_list; + + fill_answer_1_fields(protocol->thd, &field_list); + return protocol->send_result_set_metadata(&field_list, + Protocol::SEND_NUM_ROWS | + Protocol::SEND_EOF); +} + + /* Send to client answer for help request @@ -455,22 +495,11 @@ void get_all_items_for_category(THD *thd, TABLE *items, Field *pfname, 0 Successeful send */ -int send_answer_1(Protocol *protocol, String *s1, String *s2, String *s3) +static int send_answer_1(Protocol *protocol, String *s1, String *s2, String *s3) { - THD *thd= protocol->thd; - MEM_ROOT *mem_root= thd->mem_root; DBUG_ENTER("send_answer_1"); - List<Item> field_list; - field_list.push_back(new (mem_root) Item_empty_string(thd, "name", 64), - mem_root); - field_list.push_back(new (mem_root) Item_empty_string(thd, "description", 1000), - mem_root); - field_list.push_back(new (mem_root) Item_empty_string(thd, "example", 1000), - mem_root); - - if (protocol->send_result_set_metadata(&field_list, - Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF)) + if (send_answer_1_metadata(protocol)) DBUG_RETURN(1); protocol->prepare_for_resend(); @@ -483,13 +512,39 @@ int send_answer_1(Protocol *protocol, String *s1, String *s2, String *s3) } +/** + Collect field names of HELP header that will be sent to a client + + @param thd Thread data object + @param[out] field_list List of fields whose metadata should be collected for + sending to client + @param for_category need column 'source_category_name' +*/ + +static void fill_header_2_fields(THD *thd, List<Item> *field_list, + bool for_category) +{ + MEM_ROOT *mem_root= thd->mem_root; + if (for_category) + field_list->push_back(new (mem_root) + Item_empty_string(thd, "source_category_name", 64), + mem_root); + field_list->push_back(new (mem_root) + Item_empty_string(thd, "name", 64), + mem_root); + field_list->push_back(new (mem_root) + Item_empty_string(thd, "is_it_category", 1), + mem_root); +} + + /* Send to client help header SYNOPSIS send_header_2() protocol - protocol for sending - is_it_category - need column 'source_category_name' + for_category - need column 'source_category_name' IMPLEMENTATION +- -+ @@ -504,22 +559,12 @@ int send_answer_1(Protocol *protocol, String *s1, String *s2, String *s3) result of protocol->send_result_set_metadata */ -int send_header_2(Protocol *protocol, bool for_category) +static int send_header_2(Protocol *protocol, bool for_category) { - THD *thd= protocol->thd; - MEM_ROOT *mem_root= thd->mem_root; DBUG_ENTER("send_header_2"); List<Item> field_list; - if (for_category) - field_list.push_back(new (mem_root) - Item_empty_string(thd, "source_category_name", 64), - mem_root); - field_list.push_back(new (mem_root) - Item_empty_string(thd, "name", 64), - mem_root); - field_list.push_back(new (mem_root) - Item_empty_string(thd, "is_it_category", 1), - mem_root); + + fill_header_2_fields(protocol->thd, &field_list, for_category); DBUG_RETURN(protocol->send_result_set_metadata(&field_list, Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF)); @@ -639,7 +684,6 @@ SQL_SELECT *prepare_simple_select(THD *thd, Item *cond, thd Thread handler mask mask for compare with name mlen length of mask - tables list of tables, used in WHERE table goal table pfname field "name" in table @@ -650,8 +694,7 @@ SQL_SELECT *prepare_simple_select(THD *thd, Item *cond, */ SQL_SELECT *prepare_select_for_name(THD *thd, const char *mask, size_t mlen, - TABLE_LIST *tables, TABLE *table, - Field *pfname, int *error) + TABLE *table, Field *pfname, int *error) { MEM_ROOT *mem_root= thd->mem_root; Item *cond= new (mem_root) @@ -668,6 +711,205 @@ SQL_SELECT *prepare_select_for_name(THD *thd, const char *mask, size_t mlen, } +/** + Initialize the TABLE_LIST with tables used in HELP statement handling. + + @param thd Thread handler + @param tables Array of four TABLE_LIST objects to initialize with data + about the tables help_topic, help_category, help_relation, + help_keyword +*/ + +static void initialize_tables_for_help_command(THD *thd, TABLE_LIST *tables) +{ + LEX_CSTRING MYSQL_HELP_TOPIC_NAME= {STRING_WITH_LEN("help_topic") }; + LEX_CSTRING MYSQL_HELP_CATEGORY_NAME= {STRING_WITH_LEN("help_category") }; + LEX_CSTRING MYSQL_HELP_RELATION_NAME= {STRING_WITH_LEN("help_relation") }; + LEX_CSTRING MYSQL_HELP_KEYWORD_NAME= {STRING_WITH_LEN("help_keyword") }; + + tables[0].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_TOPIC_NAME, 0, + TL_READ); + tables[1].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_CATEGORY_NAME, 0, + TL_READ); + tables[2].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_RELATION_NAME, 0, + TL_READ); + tables[3].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_KEYWORD_NAME, 0, + TL_READ); + tables[0].next_global= tables[0].next_local= + tables[0].next_name_resolution_table= &tables[1]; + tables[1].next_global= tables[1].next_local= + tables[1].next_name_resolution_table= &tables[2]; + tables[2].next_global= tables[2].next_local= + tables[2].next_name_resolution_table= &tables[3]; +} + + +/** + Setup tables and fields for query. + + @param thd Thread handler + @param first_select_lex SELECT_LEX of the parsed statement + @param tables Array of tables used in handling of the HELP + statement + @param used_fields Array of fields used in handling of the HELP + statement + + @return false on success, else true. +*/ + +template <size_t M, size_t N> +static bool init_items_for_help_command(THD *thd, + SELECT_LEX *first_select_lex, + TABLE_LIST (&tables)[M], + st_find_field (& used_fields)[N]) +{ + List<TABLE_LIST> leaves; + + /* + Initialize tables and fields to be usable from items. + tables do not contain VIEWs => we can pass 0 as conds + */ + first_select_lex->context.table_list= + first_select_lex->context.first_name_resolution_table= + &tables[0]; + + if (setup_tables(thd, &first_select_lex->context, + &first_select_lex->top_join_list, + &tables[0], leaves, false, false)) + return true; + + memcpy((char*) used_fields, (char*) init_used_fields, + sizeof(used_fields[0]) * N); + if (init_fields(thd, &tables[0], used_fields, N)) + return true; + + for (size_t i= 0; i < M; i++) + tables[i].table->file->init_table_handle_for_HANDLER(); + + return false; +} + + +/** + Prepare (in the sense of prepared statement) the HELP statement. + + @param thd Thread handler + @param mask string value passed to the HELP statement + @oaram[out] fields fields for result set metadata + + @return false on success, else true. +*/ + +bool mysqld_help_prepare(THD *thd, const char *mask, List<Item> *fields) +{ + TABLE_LIST tables[4]; + st_find_field used_fields[array_elements(init_used_fields)]; + SQL_SELECT *select; + + List<String> topics_list; + + Sql_mode_instant_remove sms(thd, MODE_PAD_CHAR_TO_FULL_LENGTH); + initialize_tables_for_help_command(thd, tables); + + /* + HELP must be available under LOCK TABLES. + Reset and backup the current open tables state to + make it possible. + */ + start_new_trans new_trans(thd); + + if (open_system_tables_for_read(thd, tables)) + return true; + + auto cleanup_and_return= [&](bool ret) + { + thd->commit_whole_transaction_and_close_tables(); + new_trans.restore_old_transaction(); + return ret; + }; + + if (init_items_for_help_command(thd, thd->lex->first_select_lex(), + tables, used_fields)) + return cleanup_and_return(false); + + size_t mlen= strlen(mask); + int error; + + /* + Prepare the query 'SELECT * FROM help_topic WHERE name LIKE mask' + for execution + */ + if (!(select= + prepare_select_for_name(thd,mask, mlen, tables[0].table, + used_fields[help_topic_name].field, &error))) + return cleanup_and_return(true); + + String name, description, example; + /* + Run the query 'SELECT * FROM help_topic WHERE name LIKE mask' + */ + int count_topics= search_topics(thd, tables[0].table, used_fields, + select, &topics_list, + &name, &description, &example); + delete select; + + if (thd->is_error()) + return cleanup_and_return(true); + + if (count_topics == 0) + { + int UNINIT_VAR(key_id); + /* + Prepare the query 'SELECT * FROM help_keyword WHERE name LIKE mask' + for execution + */ + if (!(select= + prepare_select_for_name(thd, mask, mlen, tables[3].table, + used_fields[help_keyword_name].field, + &error))) + return cleanup_and_return(true); + + /* + Run the query 'SELECT * FROM help_keyword WHERE name LIKE mask' + */ + count_topics= search_keyword(thd,tables[3].table, used_fields, select, + &key_id); + delete select; + count_topics= (count_topics != 1) ? 0 : + get_topics_for_keyword(thd, tables[0].table, tables[2].table, + used_fields, key_id, &topics_list, &name, + &description, &example); + + } + + if (count_topics == 0) + { + if (!(select= + prepare_select_for_name(thd, mask, mlen, tables[1].table, + used_fields[help_category_name].field, + &error))) + return cleanup_and_return(true); + + List<String> categories_list; + int16 category_id; + int count_categories= search_categories(thd, tables[1].table, used_fields, + select, + &categories_list,&category_id); + delete select; + if (count_categories == 1) + fill_header_2_fields(thd, fields, true); + else + fill_header_2_fields(thd, fields, false); + } + else if (count_topics == 1) + fill_answer_1_fields(thd, fields); + else + fill_header_2_fields(thd, fields, false); + + return cleanup_and_return(false); +} + + /* Server-side function 'help' @@ -685,30 +927,15 @@ static bool mysqld_help_internal(THD *thd, const char *mask) Protocol *protocol= thd->protocol; SQL_SELECT *select; st_find_field used_fields[array_elements(init_used_fields)]; - List<TABLE_LIST> leaves; TABLE_LIST tables[4]; List<String> topics_list, categories_list, subcategories_list; String name, description, example; int count_topics, count_categories, error; size_t mlen= strlen(mask); - size_t i; MEM_ROOT *mem_root= thd->mem_root; - LEX_CSTRING MYSQL_HELP_TOPIC_NAME= {STRING_WITH_LEN("help_topic") }; - LEX_CSTRING MYSQL_HELP_CATEGORY_NAME= {STRING_WITH_LEN("help_category") }; - LEX_CSTRING MYSQL_HELP_RELATION_NAME= {STRING_WITH_LEN("help_relation") }; - LEX_CSTRING MYSQL_HELP_KEYWORD_NAME= {STRING_WITH_LEN("help_keyword") }; DBUG_ENTER("mysqld_help"); - tables[0].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_TOPIC_NAME, 0, TL_READ); - tables[1].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_CATEGORY_NAME, 0, TL_READ); - tables[2].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_RELATION_NAME, 0, TL_READ); - tables[3].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_KEYWORD_NAME, 0, TL_READ); - tables[0].next_global= tables[0].next_local= - tables[0].next_name_resolution_table= &tables[1]; - tables[1].next_global= tables[1].next_local= - tables[1].next_name_resolution_table= &tables[2]; - tables[2].next_global= tables[2].next_local= - tables[2].next_name_resolution_table= &tables[3]; + initialize_tables_for_help_command(thd, tables); /* HELP must be available under LOCK TABLES. @@ -720,25 +947,12 @@ static bool mysqld_help_internal(THD *thd, const char *mask) if (open_system_tables_for_read(thd, tables)) goto error2; - /* - Init tables and fields to be usable from items - tables do not contain VIEWs => we can pass 0 as conds - */ - thd->lex->first_select_lex()->context.table_list= - thd->lex->first_select_lex()->context.first_name_resolution_table= - &tables[0]; - if (setup_tables(thd, &thd->lex->first_select_lex()->context, - &thd->lex->first_select_lex()->top_join_list, - tables, leaves, FALSE, FALSE)) + if (init_items_for_help_command(thd, thd->lex->first_select_lex(), + tables, used_fields)) goto error; - memcpy((char*) used_fields, (char*) init_used_fields, sizeof(used_fields)); - if (init_fields(thd, tables, used_fields, array_elements(used_fields))) - goto error; - for (i=0; i<sizeof(tables)/sizeof(TABLE_LIST); i++) - tables[i].table->file->init_table_handle_for_HANDLER(); if (!(select= - prepare_select_for_name(thd,mask,mlen,tables,tables[0].table, + prepare_select_for_name(thd,mask,mlen,tables[0].table, used_fields[help_topic_name].field,&error))) goto error; @@ -754,7 +968,7 @@ static bool mysqld_help_internal(THD *thd, const char *mask) { int UNINIT_VAR(key_id); if (!(select= - prepare_select_for_name(thd,mask,mlen,tables,tables[3].table, + prepare_select_for_name(thd,mask,mlen,tables[3].table, used_fields[help_keyword_name].field, &error))) goto error; @@ -773,7 +987,7 @@ static bool mysqld_help_internal(THD *thd, const char *mask) int16 category_id; Field *cat_cat_id= used_fields[help_category_parent_category_id].field; if (!(select= - prepare_select_for_name(thd,mask,mlen,tables,tables[1].table, + prepare_select_for_name(thd,mask,mlen,tables[1].table, used_fields[help_category_name].field, &error))) goto error; @@ -841,7 +1055,7 @@ static bool mysqld_help_internal(THD *thd, const char *mask) send_variant_2_list(mem_root,protocol, &topics_list, "N", 0)) goto error; if (!(select= - prepare_select_for_name(thd,mask,mlen,tables,tables[1].table, + prepare_select_for_name(thd,mask,mlen,tables[1].table, used_fields[help_category_name].field,&error))) goto error; search_categories(thd, tables[1].table, used_fields, |