/* -*- 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_PCONTEXT_H_
#define _SP_PCONTEXT_H_
#ifdef USE_PRAGMA_INTERFACE
#pragma interface /* gcc class implementation */
#endif
#include "sql_string.h" // LEX_STRING
#include "mysql_com.h" // enum_field_types
#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_STRING 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.
Column_definition field_def;
/// Field-type of the SP-variable.
enum_field_types sql_type() const { return field_def.sql_type; }
public:
sp_variable(LEX_STRING _name, uint _offset)
:Sql_alloc(),
name(_name),
mode(MODE_IN),
offset(_offset),
default_value(NULL)
{ }
};
///////////////////////////////////////////////////////////////////////////
/// 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
};
/// Name of the label.
LEX_STRING 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(LEX_STRING _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:
enum enum_type
{
ERROR_CODE,
SQLSTATE,
WARNING,
NOT_FOUND,
EXCEPTION
};
/// Type of the condition value.
enum_type type;
/// SQLSTATE of the condition value.
char sql_state[SQLSTATE_LENGTH+1];
/// MySQL error code of the condition value.
uint mysqlerr;
public:
sp_condition_value(uint _mysqlerr)
:Sql_alloc(),
type(ERROR_CODE),
mysqlerr(_mysqlerr)
{ }
sp_condition_value(const char *_sql_state)
:Sql_alloc(),
type(SQLSTATE)
{
memcpy(sql_state, _sql_state, SQLSTATE_LENGTH);
sql_state[SQLSTATE_LENGTH]= 0;
}
sp_condition_value(enum_type _type)
:Sql_alloc(),
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;
};
///////////////////////////////////////////////////////////////////////////
/// 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_STRING name;
/// Value of the condition.
sp_condition_value *value;
public:
sp_condition(LEX_STRING _name, sp_condition_value *_value)
:Sql_alloc(),
name(_name),
value(_value)
{ }
};
///////////////////////////////////////////////////////////////////////////
/// 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
};
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; }
/// 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 map index in this parsing context to runtime offset.
uint var_context2runtime(uint i) const
{ return m_var_offset + i; }
/// 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, LEX_STRING 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<Column_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(LEX_STRING 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, LEX_STRING name, uint ip);
sp_label *find_label(LEX_STRING name);
sp_label *last_label()
{
sp_label *label= m_labels.head();
if (!label && m_parent)
label= m_parent->last_label();
return label;
}
sp_label *pop_label()
{ return m_labels.pop(); }
/////////////////////////////////////////////////////////////////////////
// Conditions.
/////////////////////////////////////////////////////////////////////////
bool add_condition(THD *thd, LEX_STRING name, sp_condition_value *value);
/// See comment for find_variable() above.
sp_condition_value *find_condition(LEX_STRING name,
bool current_scope_only) const;
/////////////////////////////////////////////////////////////////////////
// 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 sql_state The SQL condition state
/// @param sql_errno The error code
/// @param level The SQL condition level
///
/// @return a pointer to the found SQL-handler or NULL.
sp_handler *find_handler(const char *sql_state,
uint sql_errno,
Sql_condition::enum_warning_level level) const;
/////////////////////////////////////////////////////////////////////////
// Cursors.
/////////////////////////////////////////////////////////////////////////
bool add_cursor(LEX_STRING name);
/// See comment for find_variable() above.
bool find_cursor(LEX_STRING name, uint *poff, bool current_scope_only) const;
/// Find cursor by offset (for debugging only).
const LEX_STRING *find_cursor(uint offset) const;
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(); }
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 &);
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<LEX_STRING> m_cursors;
/// Stack of SQL-handlers.
Dynamic_array<sp_handler *> m_handlers;
/// List of labels.
List<sp_label> m_labels;
/// Children contexts, used for destruction.
Dynamic_array<sp_pcontext *> m_children;
/// Scope of this parsing context.
enum_scope m_scope;
}; // class sp_pcontext : public Sql_alloc
#endif /* _SP_PCONTEXT_H_ */
|