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sp_lex_instr Class Reference

#include <sp_instr.h>

Inheritance diagram for sp_lex_instr:
Collaboration diagram for sp_lex_instr:

Public Member Functions

 sp_lex_instr (uint ip, sp_pcontext *ctx, LEX *lex, bool is_lex_owner)
bool validate_lex_and_execute_core (THD *thd, uint *nextp, bool open_tables)
virtual bool execute (THD *thd, uint *nextp)
- Public Member Functions inherited from sp_instr
 sp_instr (uint ip, sp_pcontext *ctx)
uint get_ip () const
virtual uint get_cont_dest () const
sp_pcontextget_parsing_ctx () const
virtual uint opt_mark (sp_head *sp, List< sp_instr > *leads)
virtual uint opt_shortcut_jump (sp_head *sp, sp_instr *start)
virtual void opt_move (uint dst, List< sp_branch_instr > *ibp)
bool opt_is_marked () const
- Public Member Functions inherited from sp_printable
virtual void print (String *str)=0

Protected Member Functions

virtual bool exec_core (THD *thd, uint *nextp)=0
virtual bool is_invalid () const =0
virtual void invalidate ()=0
virtual void get_query (String *sql_query) const
virtual LEX_STRING get_expr_query () const
virtual bool on_after_expr_parsing (THD *thd)
virtual void cleanup_before_parsing (THD *thd)

Additional Inherited Members

- Static Public Member Functions inherited from Sql_alloc
static void * operator new (size_t size) throw ()
static void * operator new[] (size_t size) throw ()
static void * operator new[] (size_t size, MEM_ROOT *mem_root) throw ()
static void * operator new (size_t size, MEM_ROOT *mem_root) throw ()
static void operator delete (void *ptr, size_t size)
static void operator delete (void *ptr, MEM_ROOT *mem_root)
static void operator delete[] (void *ptr, MEM_ROOT *mem_root)
static void operator delete[] (void *ptr, size_t size)
- Protected Attributes inherited from sp_instr
bool m_marked
uint m_ip
 Instruction pointer.
sp_pcontextm_parsing_ctx
 Instruction parsing context.

Detailed Description

sp_lex_instr is a class providing the interface and base implementation for SP-instructions, whose execution is based on expression evaluation.

sp_lex_instr keeps LEX-object to be able to evaluate the expression.

sp_lex_instr also provides possibility to re-parse the original query string if for some reason the LEX-object is not valid any longer.

Definition at line 168 of file sp_instr.h.

Member Function Documentation

void sp_lex_instr::cleanup_before_parsing ( THD *  thd)
protectedvirtual

Destroy items in the free list before re-parsing the statement query string (and thus, creating new items).

Parameters
thdThread context.

Reimplemented in sp_instr_set_trigger_field.

Definition at line 694 of file sp_instr.cc.

virtual bool sp_lex_instr::exec_core ( THD *  thd,
uint *  nextp 
)
protectedpure virtual

Execute core function of instruction after all preparations (e.g. setting of proper LEX, saving part of the thread context).

Parameters
thdThread context.
nextp[out]next instruction pointer
Returns
Error flag.

Implemented in sp_instr_cpush, sp_instr_jump_case_when, sp_instr_set_case_expr, sp_instr_jump_if_not, sp_instr_freturn, sp_instr_set_trigger_field, sp_instr_set, and sp_instr_stmt.

virtual bool sp_lex_instr::execute ( THD *  thd,
uint *  nextp 
)
inlinevirtual

Execute this instruction

Parameters
thdThread context
[out]nextpindex of the next instruction to execute. (For most instructions this will be the instruction following this one). Note that this parameter is undefined in case of errors, use get_cont_dest() to find the continuation instruction for CONTINUE error handlers.
Returns
Error status.

Implements sp_instr.

Reimplemented in sp_instr_cpush, and sp_instr_stmt.

Definition at line 271 of file sp_instr.h.

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virtual LEX_STRING sp_lex_instr::get_expr_query ( ) const
inlineprotectedvirtual
Returns
the expression query string. This string can not be passed directly to the parser as it is most likely not a valid SQL-statement.
Note
as it can be seen in the get_query() implementation, get_expr_query() might return EMPTY_STR. EMPTY_STR means that no query-expression is available. That happens when class provides different implementation of get_query(). Strictly speaking, this is a drawback of the current class hierarchy.

Reimplemented in sp_lex_branch_instr, sp_instr_freturn, sp_instr_set_trigger_field, and sp_instr_set.

Definition at line 323 of file sp_instr.h.

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void sp_lex_instr::get_query ( String sql_query) const
protectedvirtual

Return the query string, which can be passed to the parser. I.e. the operation should return a valid SQL-statement query string.

Parameters
[out]sql_querySQL-statement query string.

Reimplemented in sp_instr_cpush, and sp_instr_stmt.

Definition at line 718 of file sp_instr.cc.

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virtual void sp_lex_instr::invalidate ( )
protectedpure virtual

Invalidate the object.

Implemented in sp_instr_cpush, sp_instr_jump_case_when, sp_lex_branch_instr, sp_instr_freturn, sp_instr_set_trigger_field, sp_instr_set, and sp_instr_stmt.

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virtual bool sp_lex_instr::is_invalid ( ) const
protectedpure virtual
Return values
falseif the object (i.e. LEX-object) is valid and exec_core() can be just called.
trueif the object is not valid any longer, exec_core() can not be called. The original query string should be re-parsed and a new LEX-object should be used.

Implemented in sp_instr_cpush, sp_lex_branch_instr, sp_instr_freturn, sp_instr_set_trigger_field, sp_instr_set, and sp_instr_stmt.

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virtual bool sp_lex_instr::on_after_expr_parsing ( THD *  thd)
inlineprotectedvirtual

Callback function which is called after the statement query string is successfully parsed, and the thread context has not been switched to the outer context. The thread context contains new LEX-object corresponding to the parsed query string.

Parameters
thdThread context.
Returns
Error flag.

Reimplemented in sp_instr_cpush, sp_instr_jump_case_when, sp_instr_set_case_expr, sp_instr_jump_if_not, sp_instr_freturn, sp_instr_set_trigger_field, sp_instr_set, and sp_instr_stmt.

Definition at line 336 of file sp_instr.h.

bool sp_lex_instr::validate_lex_and_execute_core ( THD *  thd,
uint *  nextp,
bool  open_tables 
)

Make a few attempts to execute the instruction.

Basically, this operation does the following things:

  • install Reprepare_observer to catch metadata changes (if any);
  • calls reset_lex_and_exec_core() to execute the instruction;
  • if the execution fails due to a change in metadata, re-parse the instruction's SQL-statement and repeat execution.
Parameters
thdThread context.
[out]nextpNext instruction pointer
open_tablesFlag to specify if the function should check read access to tables in LEX's table list and open and lock them (used in instructions which need to calculate some expression and don't execute complete statement).
Returns
Error status.

Definition at line 576 of file sp_instr.cc.

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The documentation for this class was generated from the following files: