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Diffstat (limited to 'sql/sp_rcontext.h')
| -rw-r--r-- | sql/sp_rcontext.h | 407 |
1 files changed, 407 insertions, 0 deletions
diff --git a/sql/sp_rcontext.h b/sql/sp_rcontext.h new file mode 100644 index 00000000..0e0e8921 --- /dev/null +++ b/sql/sp_rcontext.h @@ -0,0 +1,407 @@ +/* -*- C++ -*- */ +/* Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved. + + 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 _SP_RCONTEXT_H_ +#define _SP_RCONTEXT_H_ + +#ifdef USE_PRAGMA_INTERFACE +#pragma interface /* gcc class implementation */ +#endif + +#include "sql_class.h" // select_result_interceptor +#include "sp_pcontext.h" // sp_condition_value + +/////////////////////////////////////////////////////////////////////////// +// sp_rcontext declaration. +/////////////////////////////////////////////////////////////////////////// + +class sp_cursor; +class sp_lex_keeper; +class sp_instr_cpush; +class sp_instr_hpush_jump; +class Query_arena; +class sp_head; +class Item_cache; +class Virtual_tmp_table; + + +/* + This class is a runtime context of a Stored Routine. It is used in an + execution and is intended to contain all dynamic objects (i.e. objects, which + can be changed during execution), such as: + - stored routine variables; + - cursors; + - handlers; + + Runtime context is used with sp_head class. sp_head class is intended to + contain all static things, related to the stored routines (code, for example). + sp_head instance creates runtime context for the execution of a stored + routine. + + There is a parsing context (an instance of sp_pcontext class), which is used + on parsing stage. However, now it contains some necessary for an execution + things, such as definition of used stored routine variables. That's why + runtime context needs a reference to the parsing context. +*/ + +class sp_rcontext : public Sql_alloc +{ +public: + /// Construct and properly initialize a new sp_rcontext instance. The static + /// create-function is needed because we need a way to return an error from + /// the constructor. + /// + /// @param thd Thread handle. + /// @param root_parsing_ctx Top-level parsing context for this stored program. + /// @param return_value_fld Field object to store the return value + /// (for stored functions only). + /// + /// @return valid sp_rcontext object or NULL in case of OOM-error. + static sp_rcontext *create(THD *thd, + const sp_head *owner, + const sp_pcontext *root_parsing_ctx, + Field *return_value_fld, + Row_definition_list &defs); + + ~sp_rcontext(); + +private: + sp_rcontext(const sp_head *owner, + const sp_pcontext *root_parsing_ctx, + Field *return_value_fld, + bool in_sub_stmt); + + // Prevent use of copying constructor and operator. + sp_rcontext(const sp_rcontext &); + void operator=(sp_rcontext &); + +public: + /// This class stores basic information about SQL-condition, such as: + /// - SQL error code; + /// - error level; + /// - SQLSTATE; + /// - text message. + /// + /// It's used to organize runtime SQL-handler call stack. + /// + /// Standard Sql_condition class can not be used, because we don't always have + /// an Sql_condition object for an SQL-condition in Diagnostics_area. + /// + /// Eventually, this class should be moved to sql_error.h, and be a part of + /// standard SQL-condition processing (Diagnostics_area should contain an + /// object for active SQL-condition, not just information stored in DA's + /// fields). + class Sql_condition_info : public Sql_alloc, + public Sql_condition_identity + { + public: + /// Text message. + char *message; + + /// The constructor. + /// + /// @param _sql_condition The SQL condition. + /// @param arena Query arena for SP + Sql_condition_info(const Sql_condition *_sql_condition, + Query_arena *arena) + :Sql_condition_identity(*_sql_condition) + { + message= strdup_root(arena->mem_root, _sql_condition->get_message_text()); + } + }; + +private: + /// This class represents a call frame of SQL-handler (one invocation of a + /// handler). Basically, it's needed to store continue instruction pointer for + /// CONTINUE SQL-handlers. + class Handler_call_frame : public Sql_alloc + { + public: + /// SQL-condition, triggered handler activation. + const Sql_condition_info *sql_condition; + + /// Continue-instruction-pointer for CONTINUE-handlers. + /// The attribute contains 0 for EXIT-handlers. + uint continue_ip; + + /// The constructor. + /// + /// @param _sql_condition SQL-condition, triggered handler activation. + /// @param _continue_ip Continue instruction pointer. + Handler_call_frame(const Sql_condition_info *_sql_condition, + uint _continue_ip) + :sql_condition(_sql_condition), + continue_ip(_continue_ip) + { } + }; + +public: + /// Arena used to (re) allocate items on. E.g. reallocate INOUT/OUT + /// SP-variables when they don't fit into prealloced items. This is common + /// situation with String items. It is used mainly in sp_eval_func_item(). + Query_arena *callers_arena; + + /// Flag to end an open result set before start executing an SQL-handler + /// (if one is found). Otherwise the client will hang due to a violation + /// of the client/server protocol. + bool end_partial_result_set; + bool pause_state; + bool quit_func; + uint instr_ptr; + + /// The stored program for which this runtime context is created. Used for + /// checking if correct runtime context is used for variable handling, + /// and to access the package run-time context. + /// Also used by slow log. + const sp_head *m_sp; + + ///////////////////////////////////////////////////////////////////////// + // SP-variables. + ///////////////////////////////////////////////////////////////////////// + + uint argument_count() const + { + return m_root_parsing_ctx->context_var_count(); + } + + int set_variable(THD *thd, uint var_idx, Item **value); + int set_variable_row_field(THD *thd, uint var_idx, uint field_idx, + Item **value); + int set_variable_row_field_by_name(THD *thd, uint var_idx, + const LEX_CSTRING &field_name, + Item **value); + int set_variable_row(THD *thd, uint var_idx, List<Item> &items); + + int set_parameter(THD *thd, uint var_idx, Item **value) + { + DBUG_ASSERT(var_idx < argument_count()); + return set_variable(thd, var_idx, value); + } + + Item_field *get_variable(uint var_idx) const + { return m_var_items[var_idx]; } + + Item **get_variable_addr(uint var_idx) const + { return ((Item **) m_var_items.array()) + var_idx; } + + Item_field *get_parameter(uint var_idx) const + { + DBUG_ASSERT(var_idx < argument_count()); + return get_variable(var_idx); + } + + bool find_row_field_by_name_or_error(uint *field_idx, uint var_idx, + const LEX_CSTRING &field_name); + + bool set_return_value(THD *thd, Item **return_value_item); + + bool is_return_value_set() const + { return m_return_value_set; } + + ///////////////////////////////////////////////////////////////////////// + // SQL-handlers. + ///////////////////////////////////////////////////////////////////////// + + /// Push an sp_instr_hpush_jump instance to the handler call stack. + /// + /// @param entry The condition handler entry + /// + /// @return error flag. + /// @retval false on success. + /// @retval true on error. + bool push_handler(sp_instr_hpush_jump *entry); + + /// Pop and delete given number of instances from the handler + /// call stack. + /// + /// @param count Number of handler entries to pop & delete. + void pop_handlers(size_t count); + + const Sql_condition_info *raised_condition() const + { + return m_handler_call_stack.elements() ? + (*m_handler_call_stack.back())->sql_condition : NULL; + } + + /// Handle current SQL condition (if any). + /// + /// This is the public-interface function to handle SQL conditions in + /// stored routines. + /// + /// @param thd Thread handle. + /// @param ip[out] Instruction pointer to the first handler + /// instruction. + /// @param cur_spi Current SP instruction. + /// + /// @retval true if an SQL-handler has been activated. That means, all of + /// the following conditions are satisfied: + /// - the SP-instruction raised SQL-condition(s), + /// - and there is an SQL-handler to process at least one of those + /// SQL-conditions, + /// - and that SQL-handler has been activated. + /// Note, that the return value has nothing to do with "error flag" + /// semantics. + /// + /// @retval false otherwise. + bool handle_sql_condition(THD *thd, + uint *ip, + const sp_instr *cur_spi); + + /// Remove latest call frame from the handler call stack. + /// + /// @param da Diagnostics area containing handled conditions. + /// + /// @return continue instruction pointer of the removed handler. + uint exit_handler(Diagnostics_area *da); + + ///////////////////////////////////////////////////////////////////////// + // Cursors. + ///////////////////////////////////////////////////////////////////////// + + /// Push a cursor to the cursor stack. + /// + /// @param cursor The cursor + /// + void push_cursor(sp_cursor *cur); + + void pop_cursor(THD *thd); + /// Pop and delete given number of sp_cursor instance from the cursor stack. + /// + /// @param count Number of cursors to pop & delete. + void pop_cursors(THD *thd, size_t count); + + void pop_all_cursors(THD *thd) + { pop_cursors(thd, m_ccount); } + + sp_cursor *get_cursor(uint i) const + { return m_cstack[i]; } + + ///////////////////////////////////////////////////////////////////////// + // CASE expressions. + ///////////////////////////////////////////////////////////////////////// + + /// Set CASE expression to the specified value. + /// + /// @param thd Thread handler. + /// @param case_expr_id The CASE expression identifier. + /// @param case_expr_item The CASE expression value + /// + /// @return error flag. + /// @retval false on success. + /// @retval true on error. + /// + /// @note The idea is to reuse Item_cache for the expression of the one + /// CASE statement. This optimization takes place when there is CASE + /// statement inside of a loop. So, in other words, we will use the same + /// object on each iteration instead of creating a new one for each + /// iteration. + /// + /// TODO + /// Hypothetically, a type of CASE expression can be different for each + /// iteration. For instance, this can happen if the expression contains + /// a session variable (something like @@VAR) and its type is changed + /// from one iteration to another. + /// + /// In order to cope with this problem, we check type each time, when we + /// use already created object. If the type does not match, we re-create + /// Item. This also can (should?) be optimized. + bool set_case_expr(THD *thd, int case_expr_id, Item **case_expr_item_ptr); + + Item *get_case_expr(int case_expr_id) const + { return m_case_expr_holders[case_expr_id]; } + + Item ** get_case_expr_addr(int case_expr_id) const + { return (Item**) m_case_expr_holders.array() + case_expr_id; } + +private: + /// Internal function to allocate memory for arrays. + /// + /// @param thd Thread handle. + /// + /// @return error flag: false on success, true in case of failure. + bool alloc_arrays(THD *thd); + + /// Create and initialize a table to store SP-variables. + /// + /// param thd Thread handle. + /// + /// @return error flag. + /// @retval false on success. + /// @retval true on error. + bool init_var_table(THD *thd, List<Spvar_definition> &defs); + + /// Create and initialize an Item-adapter (Item_field) for each SP-var field. + /// + /// param thd Thread handle. + /// + /// @return error flag. + /// @retval false on success. + /// @retval true on error. + bool init_var_items(THD *thd, List<Spvar_definition> &defs); + + /// Create an instance of appropriate Item_cache class depending on the + /// specified type in the callers arena. + /// + /// @note We should create cache items in the callers arena, as they are + /// used between in several instructions. + /// + /// @param thd Thread handler. + /// @param item Item to get the expression type. + /// + /// @return Pointer to valid object on success, or NULL in case of error. + Item_cache *create_case_expr_holder(THD *thd, const Item *item) const; + + Virtual_tmp_table *virtual_tmp_table_for_row(uint idx); + +private: + /// Top-level (root) parsing context for this runtime context. + const sp_pcontext *m_root_parsing_ctx; + + /// Virtual table for storing SP-variables. + Virtual_tmp_table *m_var_table; + + /// Collection of Item_field proxies, each of them points to the + /// corresponding field in m_var_table. + Bounds_checked_array<Item_field *> m_var_items; + + /// This is a pointer to a field, which should contain return value for + /// stored functions (only). For stored procedures, this pointer is NULL. + Field *m_return_value_fld; + + /// Indicates whether the return value (in m_return_value_fld) has been + /// set during execution. + bool m_return_value_set; + + /// Flag to tell if the runtime context is created for a sub-statement. + bool m_in_sub_stmt; + + /// Stack of visible handlers. + Dynamic_array<sp_instr_hpush_jump *> m_handlers; + + /// Stack of caught SQL conditions. + Dynamic_array<Handler_call_frame *> m_handler_call_stack; + + /// Stack of cursors. + Bounds_checked_array<sp_cursor *> m_cstack; + + /// Current number of cursors in m_cstack. + uint m_ccount; + + /// Array of CASE expression holders. + Bounds_checked_array<Item_cache *> m_case_expr_holders; +}; // class sp_rcontext : public Sql_alloc + +#endif /* _SP_RCONTEXT_H_ */ |