#include <sp_pcontext.h>

Inheritance diagram for sp_pcontext:

Public Types
enum	enum_scope { REGULAR_SCOPE, HANDLER_SCOPE }
Public Member Functions
sp_pcontext *	push_context (THD *thd, enum_scope scope)
	Create and push a new context in the tree.
sp_pcontext *	pop_context ()
sp_pcontext *	parent_context () const
int	get_level () const
uint	diff_handlers (const sp_pcontext *ctx, bool exclusive) const
uint	diff_cursors (const sp_pcontext *ctx, bool exclusive) const
uint	max_var_index () const
uint	current_var_count () const
uint	context_var_count () const
uint	var_context2runtime (uint i) const
sp_variable *	add_variable (THD *thd, LEX_STRING name, enum enum_field_types type, sp_variable::enum_mode mode)
void	retrieve_field_definitions (List< Create_field > *field_def_lst) const
sp_variable *	find_variable (LEX_STRING name, bool current_scope_only) const
sp_variable *	find_variable (uint offset) const
void	declare_var_boundary (uint n)
int	get_num_case_exprs () const
int	push_case_expr_id ()
void	pop_case_expr_id ()
int	get_current_case_expr_id () const
sp_label *	push_label (THD *thd, LEX_STRING name, uint ip)
sp_label *	find_label (LEX_STRING name)
sp_label *	last_label ()
sp_label *	pop_label ()
bool	add_condition (THD thd, LEX_STRING name, sp_condition_value value)
sp_condition_value *	find_condition (LEX_STRING name, bool current_scope_only) const
	See comment for find_variable() above.
sp_handler *	add_handler (THD *thd, sp_handler::enum_type type)
bool	check_duplicate_handler (const sp_condition_value *cond_value) const
sp_handler *	find_handler (const char *sql_state, uint sql_errno, Sql_condition::enum_warning_level level) const
bool	add_cursor (LEX_STRING name)
bool	find_cursor (LEX_STRING name, uint *poff, bool current_scope_only) const
	See comment for find_variable() above.
const LEX_STRING *	find_cursor (uint offset) const
	Find cursor by offset (for debugging only).
uint	max_cursor_index () const
uint	current_cursor_count () const

Detailed Description

The class represents parse-time context, which keeps track of declared variables/parameters, conditions, handlers, cursors and labels.

sp_context objects are organized in a tree according to the following rules:

one sp_pcontext object corresponds for for each BEGIN..END block;
one sp_pcontext object corresponds for each exception handler;
one additional sp_pcontext object is created to contain Stored Program parameters.

sp_pcontext objects are used both at parse-time and at runtime.

During the parsing stage sp_pcontext objects are used:

to look up defined names (e.g. declared variables and visible labels);
to check for duplicates;
for error checking;
to calculate offsets to be used at runtime.

During the runtime phase, a tree of sp_pcontext objects is used:

for error checking (e.g. to check correct number of parameters);
to resolve SQL-handlers.

Member Enumeration Documentation

enum sp_pcontext::enum_scope

Enumerator:

REGULAR_SCOPE	REGULAR_SCOPE designates regular BEGIN ... END blocks.
HANDLER_SCOPE	HANDLER_SCOPE designates SQL-handler blocks.

Member Function Documentation

sp_variable * sp_pcontext::add_variable	(	THD *	thd,
		LEX_STRING	name,
		enum enum_field_types	type,
		sp_variable::enum_mode	mode
	)

Add SP-variable to the parsing context.

Parameters:

thd	Thread context.
name	Name of the SP-variable.
type	Type of the SP-variable.
mode	Mode of the SP-variable.

Returns:: instance of newly added SP-variable.

bool sp_pcontext::check_duplicate_handler ( const sp_condition_value * cond_value ) const

This is an auxilary parsing-time function to check if an SQL-handler exists in the current parsing context (current scope) for the given SQL-condition. This function is used to check for duplicates during the parsing phase.

This function can not be used during the runtime phase to check SQL-handler existence because it searches for the SQL-handler in the current scope only (during runtime, current and parent scopes should be checked according to the SQL-handler resolution rules).

Parameters:

condition_value the handler condition value (not SQL-condition!).

Return values:

true	if such SQL-handler exists.
false	otherwise.

uint sp_pcontext::context_var_count ( ) const [inline]

Returns:: the number of variables in this context alone.

uint sp_pcontext::current_var_count ( ) const [inline]

Returns:: the current number of variables used in the parent contexts (from the root), including this context.

void sp_pcontext::declare_var_boundary ( uint n ) [inline]

Set the current scope boundary (for default values).

Parameters:

n	The number of variables to skip.

uint sp_pcontext::diff_cursors	(	const sp_pcontext *	ctx,
		bool	exclusive
	)		const

Calculate and return the number of cursors to pop between the given context and this one.

Parameters:

ctx	the other parsing context.
exclusive	specifies if the last scope should be excluded.

Returns:: the number of cursors to pop between the given context and this one. If 'exclusive' is true, don't count the last scope we are leaving; this is used for LEAVE where we will jump to the cpop instructions.

uint sp_pcontext::diff_handlers	(	const sp_pcontext *	ctx,
		bool	exclusive
	)		const

Calculate and return the number of handlers to pop between the given context and this one.

Parameters:

ctx	the other parsing context.
exclusive	specifies if the last scope should be excluded.

Returns:: the number of handlers to pop between the given context and this one. If 'exclusive' is true, don't count the last scope we are leaving; this is used for LEAVE where we will jump to the hpop instructions.

sp_handler * sp_pcontext::find_handler	(	const char *	sql_state,
		uint	sql_errno,
		Sql_condition::enum_warning_level	level
	)		const

Find an SQL handler for the given SQL condition according to the SQL-handler resolution rules. This function is used at runtime.

Parameters:

sql_state	The SQL condition state
sql_errno	The error code
level	The SQL condition level

Returns:: a pointer to the found SQL-handler or NULL.

sp_variable * sp_pcontext::find_variable	(	LEX_STRING	name,
		bool	current_scope_only
	)		const

Find SP-variable by name.

The function does a linear search (from newer to older variables, in case we have shadowed names).

The function is called only at parsing time.

Parameters:

name	Variable name.
current_scope_only	A flag if we search only in current scope.

Returns:: instance of found SP-variable, or NULL if not found.

sp_variable * sp_pcontext::find_variable ( uint offset ) const

Find SP-variable by the offset in the root parsing context.

The function is used for two things:

When evaluating parameters at the beginning, and setting out parameters at the end, of invocation. (Top frame only, so no recursion then.)
For printing of sp_instr_set. (Debug mode only.)

Parameters:

offset Variable offset in the root parsing context.

Returns:: instance of found SP-variable, or NULL if not found.

uint sp_pcontext::max_var_index ( ) const [inline]

Returns:: the maximum number of variables used in this and all child contexts. For the root parsing context, this gives us the number of slots needed for variables during the runtime phase.

sp_pcontext * sp_pcontext::pop_context ( )

Pop a node from the parsing context tree.

Returns:: the parent node.

sp_pcontext * sp_pcontext::push_context	(	THD *	thd,
		sp_pcontext::enum_scope	scope
	)

Create and push a new context in the tree.

Parameters:

thd	thread context.
scope	scope of the new parsing context.

Returns:: the node created.

void sp_pcontext::retrieve_field_definitions ( List< Create_field > * field_def_lst ) const

Retrieve full type information about SP-variables in this parsing context and its children.

Parameters:

field_def_lst[out] Container to store type information.

uint sp_pcontext::var_context2runtime ( uint i ) const [inline]

Returns:: map index in this parsing context to runtime offset.

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

sp_pcontext.h
sp_pcontext.cc

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

Member Function Documentation