| Current File : //usr/include/mysql/server/private/sp_pcontext.h |
/* -*- C++ -*- */
/* Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
Copyright (c) 2009, 2020, MariaDB Corporation.
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_PCONTEXT_H_
#define _SP_PCONTEXT_H_
#ifdef USE_PRAGMA_INTERFACE
#pragma interface /* gcc class implementation */
#endif
#include "sql_string.h" // LEX_STRING
#include "field.h" // Create_field
#include "sql_array.h" // Dynamic_array
/// This class represents a stored program variable or a parameter
/// (also referenced as 'SP-variable').
class sp_variable : public Sql_alloc
{
public:
enum enum_mode
{
MODE_IN,
MODE_OUT,
MODE_INOUT
};
/// Name of the SP-variable.
LEX_CSTRING name;
/// Mode of the SP-variable.
enum_mode mode;
/// The index to the variable's value in the runtime frame.
///
/// It is calculated during parsing and used when creating sp_instr_set
/// instructions and Item_splocal items. I.e. values are set/referred by
/// array indexing in runtime.
uint offset;
/// Default value of the SP-variable (if any).
Item *default_value;
/// Full type information (field meta-data) of the SP-variable.
Spvar_definition field_def;
/// Field-type of the SP-variable.
const Type_handler *type_handler() const
{ return field_def.type_handler(); }
public:
sp_variable(const LEX_CSTRING *name_arg, uint offset_arg)
:Sql_alloc(),
name(*name_arg),
mode(MODE_IN),
offset(offset_arg),
default_value(NULL)
{ }
/*
Find a ROW field by its qualified name.
@param var_name - the name of the variable
@param field_name - the name of the variable field
@param[OUT] row_field_offset - the index of the field
@retval NULL if the variable with the given name was not found,
or it is not a row variable, or it does not have a field
with the given name, or a non-null pointer otherwise.
row_field_offset[0] is set only when the method returns !NULL.
*/
const Spvar_definition *find_row_field(const LEX_CSTRING *var_name,
const LEX_CSTRING *field_name,
uint *row_field_offset);
};
///////////////////////////////////////////////////////////////////////////
/// This class represents an SQL/PSM label. Can refer to the identifier
/// used with the "label_name:" construct which may precede some SQL/PSM
/// statements, or to an implicit implementation-dependent identifier which
/// the parser inserts before a high-level flow control statement such as
/// IF/WHILE/REPEAT/LOOP, when such statement is rewritten into a
/// combination of low-level jump/jump_if instructions and labels.
class sp_label : public Sql_alloc
{
public:
enum enum_type
{
/// Implicit label generated by parser.
IMPLICIT,
/// Label at BEGIN.
BEGIN,
/// Label at iteration control
ITERATION,
/// Label for jump
GOTO
};
/// Name of the label.
LEX_CSTRING name;
/// Instruction pointer of the label.
uint ip;
/// Type of the label.
enum_type type;
/// Scope of the label.
class sp_pcontext *ctx;
public:
sp_label(const LEX_CSTRING *_name,
uint _ip, enum_type _type, sp_pcontext *_ctx)
:Sql_alloc(),
name(*_name),
ip(_ip),
type(_type),
ctx(_ctx)
{ }
};
///////////////////////////////////////////////////////////////////////////
/// This class represents condition-value term in DECLARE CONDITION or
/// DECLARE HANDLER statements. sp_condition_value has little to do with
/// SQL-conditions.
///
/// In some sense, this class is a union -- a set of filled attributes
/// depends on the sp_condition_value::type value.
class sp_condition_value : public Sql_alloc, public Sql_state_errno
{
bool m_is_user_defined;
public:
enum enum_type
{
ERROR_CODE,
SQLSTATE,
WARNING,
NOT_FOUND,
EXCEPTION
};
/// Type of the condition value.
enum_type type;
public:
sp_condition_value(uint _mysqlerr)
:Sql_alloc(),
Sql_state_errno(_mysqlerr),
m_is_user_defined(false),
type(ERROR_CODE)
{ }
sp_condition_value(uint _mysqlerr, const char *_sql_state)
:Sql_alloc(),
Sql_state_errno(_mysqlerr, _sql_state),
m_is_user_defined(false),
type(ERROR_CODE)
{ }
sp_condition_value(const char *_sql_state, bool is_user_defined= false)
:Sql_alloc(),
Sql_state_errno(0, _sql_state),
m_is_user_defined(is_user_defined),
type(SQLSTATE)
{ }
sp_condition_value(enum_type _type)
:Sql_alloc(),
m_is_user_defined(false),
type(_type)
{
DBUG_ASSERT(type != ERROR_CODE && type != SQLSTATE);
}
/// Check if two instances of sp_condition_value are equal or not.
///
/// @param cv another instance of sp_condition_value to check.
///
/// @return true if the instances are equal, false otherwise.
bool equals(const sp_condition_value *cv) const;
/**
Checks if this condition is OK for search.
See also sp_context::find_handler().
@param identity - The condition identity
@param found_cv - A previously found matching condition or NULL.
@return true - If the current value matches identity and
makes a stronger match than the previously
found condition found_cv.
@return false - If the current value does not match identity,
of the current value makes a weaker match than found_cv.
*/
bool matches(const Sql_condition_identity &identity,
const sp_condition_value *found_cv) const;
Sql_user_condition_identity get_user_condition_identity() const
{
return Sql_user_condition_identity(m_is_user_defined ? this : NULL);
}
};
class sp_condition_value_user_defined: public sp_condition_value
{
public:
sp_condition_value_user_defined()
:sp_condition_value("45000", true)
{ }
};
///////////////////////////////////////////////////////////////////////////
/// This class represents 'DECLARE CONDITION' statement.
/// sp_condition has little to do with SQL-conditions.
class sp_condition : public Sql_alloc
{
public:
/// Name of the condition.
LEX_CSTRING name;
/// Value of the condition.
sp_condition_value *value;
public:
sp_condition(const LEX_CSTRING *name_arg, sp_condition_value *value_arg)
:Sql_alloc(),
name(*name_arg),
value(value_arg)
{ }
sp_condition(const char *name_arg, size_t name_length_arg,
sp_condition_value *value_arg)
:value(value_arg)
{
name.str= name_arg;
name.length= name_length_arg;
}
bool eq_name(const LEX_CSTRING *str) const
{
return system_charset_info->strnncoll(name.str, name.length,
str->str, str->length) == 0;
}
};
///////////////////////////////////////////////////////////////////////////
/**
class sp_pcursor.
Stores information about a cursor:
- Cursor's name in LEX_STRING.
- Cursor's formal parameter descriptions.
Formal parameter descriptions reside in a separate context block,
pointed by the "m_param_context" member.
m_param_context can be NULL. This means a cursor with no parameters.
Otherwise, the number of variables in m_param_context means
the number of cursor's formal parameters.
Note, m_param_context can be not NULL, but have no variables.
This is also means a cursor with no parameters (similar to NULL).
*/
class sp_pcursor: public LEX_CSTRING
{
class sp_pcontext *m_param_context; // Formal parameters
class sp_lex_cursor *m_lex; // The cursor statement LEX
public:
sp_pcursor(const LEX_CSTRING *name, class sp_pcontext *param_ctx,
class sp_lex_cursor *lex)
:LEX_CSTRING(*name), m_param_context(param_ctx), m_lex(lex)
{ }
class sp_pcontext *param_context() const { return m_param_context; }
class sp_lex_cursor *lex() const { return m_lex; }
bool check_param_count_with_error(uint param_count) const;
};
///////////////////////////////////////////////////////////////////////////
/// This class represents 'DECLARE HANDLER' statement.
class sp_handler : public Sql_alloc
{
public:
/// Enumeration of possible handler types.
/// Note: UNDO handlers are not (and have never been) supported.
enum enum_type
{
EXIT,
CONTINUE
};
/// Handler type.
enum_type type;
/// Conditions caught by this handler.
List<sp_condition_value> condition_values;
public:
/// The constructor.
///
/// @param _type SQL-handler type.
sp_handler(enum_type _type)
:Sql_alloc(),
type(_type)
{ }
};
///////////////////////////////////////////////////////////////////////////
/// The class represents parse-time context, which keeps track of declared
/// variables/parameters, conditions, handlers, cursors and labels.
///
/// sp_pcontext 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.
class sp_pcontext : public Sql_alloc
{
public:
enum enum_scope
{
/// REGULAR_SCOPE designates regular BEGIN ... END blocks.
REGULAR_SCOPE,
/// HANDLER_SCOPE designates SQL-handler blocks.
HANDLER_SCOPE
};
class Lex_for_loop: public Lex_for_loop_st
{
public:
/*
The label poiting to the body start,
either explicit or automatically generated.
Used during generation of "ITERATE loop_label"
to check if "loop_label" is a FOR loop label.
- In case of a FOR loop, some additional code
(cursor fetch or iteger increment) is generated before
the backward jump to the beginning of the loop body.
- In case of other loop types (WHILE, REPEAT)
only the jump is generated.
*/
const sp_label *m_start_label;
Lex_for_loop()
:m_start_label(NULL)
{ Lex_for_loop_st::init(); }
Lex_for_loop(const Lex_for_loop_st &for_loop, const sp_label *start)
:m_start_label(start)
{
Lex_for_loop_st::operator=(for_loop);
}
};
public:
sp_pcontext();
~sp_pcontext();
/// Create and push a new context in the tree.
/// @param thd thread context.
/// @param scope scope of the new parsing context.
/// @return the node created.
sp_pcontext *push_context(THD *thd, enum_scope scope);
/// Pop a node from the parsing context tree.
/// @return the parent node.
sp_pcontext *pop_context();
sp_pcontext *parent_context() const
{ return m_parent; }
sp_pcontext *child_context(uint i) const
{ return i < m_children.elements() ? m_children.at(i) : NULL; }
/// Calculate and return the number of handlers to pop between the given
/// context and this one.
///
/// @param ctx the other parsing context.
/// @param exclusive specifies if the last scope should be excluded.
///
/// @return 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.
uint diff_handlers(const sp_pcontext *ctx, bool exclusive) const;
/// Calculate and return the number of cursors to pop between the given
/// context and this one.
///
/// @param ctx the other parsing context.
/// @param exclusive specifies if the last scope should be excluded.
///
/// @return 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 diff_cursors(const sp_pcontext *ctx, bool exclusive) const;
/////////////////////////////////////////////////////////////////////////
// SP-variables (parameters and variables).
/////////////////////////////////////////////////////////////////////////
/// @return 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.
uint max_var_index() const
{ return m_max_var_index; }
/// @return the current number of variables used in the parent contexts
/// (from the root), including this context.
uint current_var_count() const
{ return m_var_offset + (uint)m_vars.elements(); }
/// @return the number of variables in this context alone.
uint context_var_count() const
{ return (uint)m_vars.elements(); }
/// return the i-th variable on the current context
sp_variable *get_context_variable(uint i) const
{
DBUG_ASSERT(i < m_vars.elements());
return m_vars.at(i);
}
/*
Return the i-th last context variable.
If i is 0, then return the very last variable in m_vars.
*/
sp_variable *get_last_context_variable(uint i= 0) const
{
DBUG_ASSERT(i < m_vars.elements());
return m_vars.at(m_vars.elements() - i - 1);
}
/// Add SP-variable to the parsing context.
///
/// @param thd Thread context.
/// @param name Name of the SP-variable.
///
/// @return instance of newly added SP-variable.
sp_variable *add_variable(THD *thd, const LEX_CSTRING *name);
/// Retrieve full type information about SP-variables in this parsing
/// context and its children.
///
/// @param field_def_lst[out] Container to store type information.
void retrieve_field_definitions(List<Spvar_definition> *field_def_lst) 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.
///
/// @param name Variable name.
/// @param current_scope_only A flag if we search only in current scope.
///
/// @return instance of found SP-variable, or NULL if not found.
sp_variable *find_variable(const LEX_CSTRING *name, bool current_scope_only) 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.)
///
/// @param offset Variable offset in the root parsing context.
///
/// @return instance of found SP-variable, or NULL if not found.
sp_variable *find_variable(uint offset) const;
/// Set the current scope boundary (for default values).
///
/// @param n The number of variables to skip.
void declare_var_boundary(uint n)
{ m_pboundary= n; }
/////////////////////////////////////////////////////////////////////////
// CASE expressions.
/////////////////////////////////////////////////////////////////////////
int register_case_expr()
{ return m_num_case_exprs++; }
int get_num_case_exprs() const
{ return m_num_case_exprs; }
bool push_case_expr_id(int case_expr_id)
{ return m_case_expr_ids.append(case_expr_id); }
void pop_case_expr_id()
{ m_case_expr_ids.pop(); }
int get_current_case_expr_id() const
{ return *m_case_expr_ids.back(); }
/////////////////////////////////////////////////////////////////////////
// Labels.
/////////////////////////////////////////////////////////////////////////
sp_label *push_label(THD *thd, const LEX_CSTRING *name, uint ip,
sp_label::enum_type type, List<sp_label> * list);
sp_label *push_label(THD *thd, const LEX_CSTRING *name, uint ip,
sp_label::enum_type type)
{ return push_label(thd, name, ip, type, &m_labels); }
sp_label *push_goto_label(THD *thd, const LEX_CSTRING *name, uint ip,
sp_label::enum_type type)
{ return push_label(thd, name, ip, type, &m_goto_labels); }
sp_label *push_label(THD *thd, const LEX_CSTRING *name, uint ip)
{ return push_label(thd, name, ip, sp_label::IMPLICIT); }
sp_label *push_goto_label(THD *thd, const LEX_CSTRING *name, uint ip)
{ return push_goto_label(thd, name, ip, sp_label::GOTO); }
sp_label *find_label(const LEX_CSTRING *name);
sp_label *find_goto_label(const LEX_CSTRING *name, bool recusive);
sp_label *find_goto_label(const LEX_CSTRING *name)
{ return find_goto_label(name, true); }
sp_label *find_label_current_loop_start();
sp_label *last_label()
{
sp_label *label= m_labels.head();
if (!label && m_parent)
label= m_parent->last_label();
return label;
}
sp_label *last_goto_label()
{
return m_goto_labels.head();
}
sp_label *pop_label()
{ return m_labels.pop(); }
bool block_label_declare(LEX_CSTRING *label)
{
sp_label *lab= find_label(label);
if (lab)
{
my_error(ER_SP_LABEL_REDEFINE, MYF(0), label->str);
return true;
}
return false;
}
/////////////////////////////////////////////////////////////////////////
// Conditions.
/////////////////////////////////////////////////////////////////////////
bool add_condition(THD *thd, const LEX_CSTRING *name,
sp_condition_value *value);
/// See comment for find_variable() above.
sp_condition_value *find_condition(const LEX_CSTRING *name,
bool current_scope_only) const;
sp_condition_value *
find_declared_or_predefined_condition(THD *thd, const LEX_CSTRING *name) const;
bool declare_condition(THD *thd, const LEX_CSTRING *name,
sp_condition_value *val)
{
if (find_condition(name, true))
{
my_error(ER_SP_DUP_COND, MYF(0), name->str);
return true;
}
return add_condition(thd, name, val);
}
/////////////////////////////////////////////////////////////////////////
// Handlers.
/////////////////////////////////////////////////////////////////////////
sp_handler *add_handler(THD* thd, sp_handler::enum_type type);
/// 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).
///
/// @param condition_value the handler condition value
/// (not SQL-condition!).
///
/// @retval true if such SQL-handler exists.
/// @retval false otherwise.
bool check_duplicate_handler(const sp_condition_value *cond_value) const;
/// Find an SQL handler for the given SQL condition according to the
/// SQL-handler resolution rules. This function is used at runtime.
///
/// @param value The error code and the SQL state
/// @param level The SQL condition level
///
/// @return a pointer to the found SQL-handler or NULL.
sp_handler *find_handler(const Sql_condition_identity &identity) const;
/////////////////////////////////////////////////////////////////////////
// Cursors.
/////////////////////////////////////////////////////////////////////////
bool add_cursor(const LEX_CSTRING *name, sp_pcontext *param_ctx,
class sp_lex_cursor *lex);
/// See comment for find_variable() above.
const sp_pcursor *find_cursor(const LEX_CSTRING *name,
uint *poff, bool current_scope_only) const;
const sp_pcursor *find_cursor_with_error(const LEX_CSTRING *name,
uint *poff,
bool current_scope_only) const
{
const sp_pcursor *pcursor= find_cursor(name, poff, current_scope_only);
if (!pcursor)
{
my_error(ER_SP_CURSOR_MISMATCH, MYF(0), name->str);
return NULL;
}
return pcursor;
}
/// Find cursor by offset (for SHOW {PROCEDURE|FUNCTION} CODE only).
const sp_pcursor *find_cursor(uint offset) const;
const sp_pcursor *get_cursor_by_local_frame_offset(uint offset) const
{ return &m_cursors.at(offset); }
uint cursor_offset() const
{ return m_cursor_offset; }
uint frame_cursor_count() const
{ return (uint)m_cursors.elements(); }
uint max_cursor_index() const
{ return m_max_cursor_index + (uint)m_cursors.elements(); }
uint current_cursor_count() const
{ return m_cursor_offset + (uint)m_cursors.elements(); }
void set_for_loop(const Lex_for_loop_st &for_loop)
{
m_for_loop= Lex_for_loop(for_loop, last_label());
}
const Lex_for_loop &for_loop()
{
return m_for_loop;
}
private:
/// Constructor for a tree node.
/// @param prev the parent parsing context
/// @param scope scope of this parsing context
sp_pcontext(sp_pcontext *prev, enum_scope scope);
void init(uint var_offset, uint cursor_offset, int num_case_expressions);
/* Prevent use of these */
sp_pcontext(const sp_pcontext &);
void operator=(sp_pcontext &);
sp_condition_value *find_predefined_condition(const LEX_CSTRING *name) const;
private:
/// m_max_var_index -- number of variables (including all types of arguments)
/// in this context including all children contexts.
///
/// m_max_var_index >= m_vars.elements().
///
/// m_max_var_index of the root parsing context contains number of all
/// variables (including arguments) in all enclosed contexts.
uint m_max_var_index;
/// The maximum sub context's framesizes.
uint m_max_cursor_index;
/// Parent context.
sp_pcontext *m_parent;
/// An index of the first SP-variable in this parsing context. The index
/// belongs to a runtime table of SP-variables.
///
/// Note:
/// - m_var_offset is 0 for root parsing context;
/// - m_var_offset is different for all nested parsing contexts.
uint m_var_offset;
/// Cursor offset for this context.
uint m_cursor_offset;
/// Boundary for finding variables in this context. This is the number of
/// variables currently "invisible" to default clauses. This is normally 0,
/// but will be larger during parsing of DECLARE ... DEFAULT, to get the
/// scope right for DEFAULT values.
uint m_pboundary;
int m_num_case_exprs;
/// SP parameters/variables.
Dynamic_array<sp_variable *> m_vars;
/// Stack of CASE expression ids.
Dynamic_array<int> m_case_expr_ids;
/// Stack of SQL-conditions.
Dynamic_array<sp_condition *> m_conditions;
/// Stack of cursors.
Dynamic_array<sp_pcursor> m_cursors;
/// Stack of SQL-handlers.
Dynamic_array<sp_handler *> m_handlers;
/*
In the below example the label <<lab>> has two meanings:
- GOTO lab : must go before the beginning of the loop
- CONTINUE lab : must go to the beginning of the loop
We solve this by storing block labels and goto labels into separate lists.
BEGIN
<<lab>>
FOR i IN a..10 LOOP
...
GOTO lab;
...
CONTINUE lab;
...
END LOOP;
END;
*/
/// List of block labels
List<sp_label> m_labels;
/// List of goto labels
List<sp_label> m_goto_labels;
/// Children contexts, used for destruction.
Dynamic_array<sp_pcontext *> m_children;
/// Scope of this parsing context.
enum_scope m_scope;
/// FOR LOOP characteristics
Lex_for_loop m_for_loop;
}; // class sp_pcontext : public Sql_alloc
#endif /* _SP_PCONTEXT_H_ */