plpgsql.h

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/*-------------------------------------------------------------------------
 *
 * plpgsql.h		- Definitions for the PL/pgSQL
 *			  procedural language
 *
 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.95 2008/01/01 19:46:00 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#ifndef PLPGSQL_H
#define PLPGSQL_H

#include "postgres.h"

#include "fmgr.h"
#include "miscadmin.h"
#include "commands/trigger.h"
#include "executor/spi.h"
#include "utils/tuplestore.h"

/**********************************************************************
 * Definitions
 **********************************************************************/

/* ----------
 * Compiler's namestack item types
 * ----------
 */
enum
{
	PLPGSQL_NSTYPE_LABEL,
	PLPGSQL_NSTYPE_VAR,
	PLPGSQL_NSTYPE_ROW,
	PLPGSQL_NSTYPE_REC
};

/* ----------
 * Datum array node types
 * ----------
 */
enum
{
	PLPGSQL_DTYPE_VAR,
	PLPGSQL_DTYPE_ROW,
	PLPGSQL_DTYPE_REC,
	PLPGSQL_DTYPE_RECFIELD,
	PLPGSQL_DTYPE_ARRAYELEM,
	PLPGSQL_DTYPE_EXPR,
	PLPGSQL_DTYPE_TRIGARG
};

/* ----------
 * Variants distinguished in PLpgSQL_type structs
 * ----------
 */
enum
{
	PLPGSQL_TTYPE_SCALAR,		/* scalar types and domains */
	PLPGSQL_TTYPE_ROW,			/* composite types */
	PLPGSQL_TTYPE_REC,			/* RECORD pseudotype */
	PLPGSQL_TTYPE_PSEUDO		/* other pseudotypes */
};

/* ----------
 * Execution tree node types
 * ----------
 */
enum
{
	PLPGSQL_STMT_BLOCK,
	PLPGSQL_STMT_ASSIGN,
	PLPGSQL_STMT_IF,
	PLPGSQL_STMT_LOOP,
	PLPGSQL_STMT_WHILE,
	PLPGSQL_STMT_FORI,
	PLPGSQL_STMT_FORS,
	PLPGSQL_STMT_EXIT,
	PLPGSQL_STMT_RETURN,
	PLPGSQL_STMT_RETURN_NEXT,
	PLPGSQL_STMT_RETURN_QUERY,
	PLPGSQL_STMT_RAISE,
	PLPGSQL_STMT_EXECSQL,
	PLPGSQL_STMT_DYNEXECUTE,
	PLPGSQL_STMT_DYNFORS,
	PLPGSQL_STMT_GETDIAG,
	PLPGSQL_STMT_OPEN,
	PLPGSQL_STMT_FETCH,
	PLPGSQL_STMT_CLOSE,
	PLPGSQL_STMT_PERFORM
};


/* ----------
 * Execution node return codes
 * ----------
 */
enum
{
	PLPGSQL_RC_OK,
	PLPGSQL_RC_EXIT,
	PLPGSQL_RC_RETURN,
	PLPGSQL_RC_CONTINUE
};

/* ----------
 * GET DIAGNOSTICS system attrs
 * ----------
 */
enum
{
	PLPGSQL_GETDIAG_ROW_COUNT,
	PLPGSQL_GETDIAG_RESULT_OID
};


/**********************************************************************
 * Node and structure definitions
 **********************************************************************/


typedef struct
{								/* Dynamic string control structure */
	int			alloc;
	int			used;			/* Including NUL terminator */
	char	   *value;
} PLpgSQL_dstring;


typedef struct
{								/* Postgres data type */
	char	   *typname;		/* (simple) name of the type */
	Oid			typoid;			/* OID of the data type */
	int			ttype;			/* PLPGSQL_TTYPE_ code */
	int16		typlen;			/* stuff copied from its pg_type entry */
	bool		typbyval;
	Oid			typrelid;
	Oid			typioparam;
	FmgrInfo	typinput;		/* lookup info for typinput function */
	int32		atttypmod;		/* typmod (taken from someplace else) */
} PLpgSQL_type;


/*
 * PLpgSQL_datum is the common supertype for PLpgSQL_expr, PLpgSQL_var,
 * PLpgSQL_row, PLpgSQL_rec, PLpgSQL_recfield, PLpgSQL_arrayelem, and
 * PLpgSQL_trigarg
 */
typedef struct
{								/* Generic datum array item		*/
	int			dtype;
	int			dno;
} PLpgSQL_datum;

/*
 * The variants PLpgSQL_var, PLpgSQL_row, and PLpgSQL_rec share these
 * fields
 */
typedef struct
{								/* Scalar or composite variable */
	int			dtype;
	int			dno;
	char	   *refname;
	int			lineno;
} PLpgSQL_variable;

typedef struct PLpgSQL_expr
{								/* SQL Query to plan and execute	*/
	int			dtype;
	int			exprno;
	char	   *query;
	SPIPlanPtr	plan;
	Oid		   *plan_argtypes;
	/* fields for "simple expression" fast-path execution: */
	Expr	   *expr_simple_expr;		/* NULL means not a simple expr */
	int			expr_simple_generation; /* plancache generation we checked */
	Oid			expr_simple_type;		/* result type Oid, if simple */

	/*
	 * if expr is simple AND prepared in current eval_estate,
	 * expr_simple_state is valid.	Test validity by seeing if expr_simple_id
	 * matches eval_estate_simple_id.
	 */
	ExprState  *expr_simple_state;
	long int	expr_simple_id;

	/* params to pass to expr */
	int			nparams;
	int			params[1];		/* VARIABLE SIZE ARRAY ... must be last */
} PLpgSQL_expr;


typedef struct
{								/* Scalar variable */
	int			dtype;
	int			varno;
	char	   *refname;
	int			lineno;

	PLpgSQL_type *datatype;
	int			isconst;
	int			notnull;
	PLpgSQL_expr *default_val;
	PLpgSQL_expr *cursor_explicit_expr;
	int			cursor_explicit_argrow;
	int			cursor_options;

	Datum		value;
	bool		isnull;
	bool		freeval;
} PLpgSQL_var;


typedef struct
{								/* Row variable */
	int			dtype;
	int			rowno;
	char	   *refname;
	int			lineno;

	TupleDesc	rowtupdesc;

	/*
	 * Note: TupleDesc is only set up for named rowtypes, else it is NULL.
	 *
	 * Note: if the underlying rowtype contains a dropped column, the
	 * corresponding fieldnames[] entry will be NULL, and there is no
	 * corresponding var (varnos[] will be -1).
	 */
	int			nfields;
	char	  **fieldnames;
	int		   *varnos;
} PLpgSQL_row;


typedef struct
{								/* Record variable (non-fixed structure) */
	int			dtype;
	int			recno;
	char	   *refname;
	int			lineno;

	HeapTuple	tup;
	TupleDesc	tupdesc;
	bool		freetup;
	bool		freetupdesc;
} PLpgSQL_rec;


typedef struct
{								/* Field in record */
	int			dtype;
	int			rfno;
	char	   *fieldname;
	int			recparentno;	/* dno of parent record */
} PLpgSQL_recfield;


typedef struct
{								/* Element of array variable */
	int			dtype;
	int			dno;
	PLpgSQL_expr *subscript;
	int			arrayparentno;	/* dno of parent array variable */
} PLpgSQL_arrayelem;


typedef struct
{								/* Positional argument to trigger	*/
	int			dtype;
	int			dno;
	PLpgSQL_expr *argnum;
} PLpgSQL_trigarg;


typedef struct
{								/* Item in the compilers namestack	*/
	int			itemtype;
	int			itemno;
	char		name[1];
} PLpgSQL_nsitem;


/* XXX: consider adapting this to use List */
typedef struct PLpgSQL_ns
{								/* Compiler namestack level		*/
	int			items_alloc;
	int			items_used;
	PLpgSQL_nsitem **items;
	struct PLpgSQL_ns *upper;
} PLpgSQL_ns;


typedef struct
{								/* Generic execution node		*/
	int			cmd_type;
	int			lineno;
} PLpgSQL_stmt;


typedef struct PLpgSQL_condition
{								/* One EXCEPTION condition name */
	int			sqlerrstate;	/* SQLSTATE code */
	char	   *condname;		/* condition name (for debugging) */
	struct PLpgSQL_condition *next;
} PLpgSQL_condition;

typedef struct
{
	int			sqlstate_varno;
	int			sqlerrm_varno;
	List	   *exc_list;		/* List of WHEN clauses */
} PLpgSQL_exception_block;

typedef struct
{								/* One EXCEPTION ... WHEN clause */
	int			lineno;
	PLpgSQL_condition *conditions;
	List	   *action;			/* List of statements */
} PLpgSQL_exception;


typedef struct
{								/* Block of statements			*/
	int			cmd_type;
	int			lineno;
	char	   *label;
	List	   *body;			/* List of statements */
	int			n_initvars;
	int		   *initvarnos;
	PLpgSQL_exception_block *exceptions;
} PLpgSQL_stmt_block;


typedef struct
{								/* Assign statement			*/
	int			cmd_type;
	int			lineno;
	int			varno;
	PLpgSQL_expr *expr;
} PLpgSQL_stmt_assign;

typedef struct
{								/* PERFORM statement		*/
	int			cmd_type;
	int			lineno;
	PLpgSQL_expr *expr;
} PLpgSQL_stmt_perform;

typedef struct
{								/* Get Diagnostics item		*/
	int			kind;			/* id for diagnostic value desired */
	int			target;			/* where to assign it */
} PLpgSQL_diag_item;

typedef struct
{								/* Get Diagnostics statement		*/
	int			cmd_type;
	int			lineno;
	List	   *diag_items;		/* List of PLpgSQL_diag_item */
} PLpgSQL_stmt_getdiag;


typedef struct
{								/* IF statement				*/
	int			cmd_type;
	int			lineno;
	PLpgSQL_expr *cond;
	List	   *true_body;		/* List of statements */
	List	   *false_body;		/* List of statements */
} PLpgSQL_stmt_if;


typedef struct
{								/* Unconditional LOOP statement		*/
	int			cmd_type;
	int			lineno;
	char	   *label;
	List	   *body;			/* List of statements */
} PLpgSQL_stmt_loop;


typedef struct
{								/* WHILE cond LOOP statement		*/
	int			cmd_type;
	int			lineno;
	char	   *label;
	PLpgSQL_expr *cond;
	List	   *body;			/* List of statements */
} PLpgSQL_stmt_while;


typedef struct
{								/* FOR statement with integer loopvar	*/
	int			cmd_type;
	int			lineno;
	char	   *label;
	PLpgSQL_var *var;
	PLpgSQL_expr *lower;
	PLpgSQL_expr *upper;
	PLpgSQL_expr *step;			/* NULL means default (ie, BY 1) */
	int			reverse;