postgresql/src/include/parser/parse_node.h

/*-------------------------------------------------------------------------
 *
 * parse_node.h
 *		Internal definitions for parser
 *
 *
 * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.67 2010/01/02 16:58:07 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef PARSE_NODE_H
#define PARSE_NODE_H

#include "nodes/parsenodes.h"
#include "utils/relcache.h"


/*
 * Function signatures for parser hooks
 */
typedef struct ParseState ParseState;

typedef Node * (*PreParseColumnRefHook) (ParseState *pstate, ColumnRef *cref);
typedef Node * (*PostParseColumnRefHook) (ParseState *pstate, ColumnRef *cref, Node *var);
typedef Node * (*ParseParamRefHook) (ParseState *pstate, ParamRef *pref);
typedef Node * (*CoerceParamHook) (ParseState *pstate, Param *param,
								   Oid targetTypeId, int32 targetTypeMod,
								   int location);


/*
 * State information used during parse analysis
 *
 * parentParseState: NULL in a top-level ParseState.  When parsing a subquery,
 * links to current parse state of outer query.
 *
 * p_sourcetext: source string that generated the raw parsetree being
 * analyzed, or NULL if not available.	(The string is used only to
 * generate cursor positions in error messages: we need it to convert
 * byte-wise locations in parse structures to character-wise cursor
 * positions.)
 *
 * p_rtable: list of RTEs that will become the rangetable of the query.
 * Note that neither relname nor refname of these entries are necessarily
 * unique; searching the rtable by name is a bad idea.
 *
 * p_joinexprs: list of JoinExpr nodes associated with p_rtable entries.
 * This is one-for-one with p_rtable, but contains NULLs for non-join
 * RTEs, and may be shorter than p_rtable if the last RTE(s) aren't joins.
 *
 * p_joinlist: list of join items (RangeTblRef and JoinExpr nodes) that
 * will become the fromlist of the query's top-level FromExpr node.
 *
 * p_relnamespace: list of RTEs that represents the current namespace for
 * table lookup, ie, those RTEs that are accessible by qualified names.
 * This may be just a subset of the rtable + joinlist, and/or may contain
 * entries that are not yet added to the main joinlist.
 *
 * p_varnamespace: list of RTEs that represents the current namespace for
 * column lookup, ie, those RTEs that are accessible by unqualified names.
 * This is different from p_relnamespace because a JOIN without an alias does
 * not hide the contained tables (so they must still be in p_relnamespace)
 * but it does hide their columns (unqualified references to the columns must
 * refer to the JOIN, not the member tables).  Other special RTEs such as
 * NEW/OLD for rules may also appear in just one of these lists.
 *
 * p_ctenamespace: list of CommonTableExprs (WITH items) that are visible
 * at the moment.  This is different from p_relnamespace because you have
 * to make an RTE before you can access a CTE.
 *
 * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet
 * visible due to scope rules.	This is used to help improve error messages.
 *
 * p_parent_cte: CommonTableExpr that immediately contains the current query,
 * if any.
 *
 * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses.
 * We collect these while transforming expressions and then transform them
 * afterwards (so that any resjunk tlist items needed for the sort/group
 * clauses end up at the end of the query tlist).  A WindowDef's location in
 * this list, counting from 1, is the winref number to use to reference it.
 */
struct ParseState
{
	struct ParseState *parentParseState;		/* stack link */
	const char *p_sourcetext;	/* source text, or NULL if not available */
	List	   *p_rtable;		/* range table so far */
	List	   *p_joinexprs;	/* JoinExprs for RTE_JOIN p_rtable entries */
	List	   *p_joinlist;		/* join items so far (will become FromExpr
								 * node's fromlist) */
	List	   *p_relnamespace; /* current namespace for relations */
	List	   *p_varnamespace; /* current namespace for columns */
	List	   *p_ctenamespace; /* current namespace for common table exprs */
	List	   *p_future_ctes;	/* common table exprs not yet in namespace */
	CommonTableExpr *p_parent_cte;		/* this query's containing CTE */
	List	   *p_windowdefs;	/* raw representations of window clauses */
	int			p_next_resno;	/* next targetlist resno to assign */
	List	   *p_locking_clause;		/* raw FOR UPDATE/FOR SHARE info */
	Node	   *p_value_substitute;		/* what to replace VALUE with, if any */
	bool		p_hasAggs;
	bool		p_hasWindowFuncs;
	bool		p_hasSubLinks;
	bool		p_is_insert;
	bool		p_is_update;
	bool		p_locked_from_parent;
	Relation	p_target_relation;
	RangeTblEntry *p_target_rangetblentry;

	/*
	 * Optional hook functions for parser callbacks.  These are null unless
	 * set up by the caller of make_parsestate.
	 */
	PreParseColumnRefHook p_pre_columnref_hook;
	PostParseColumnRefHook p_post_columnref_hook;
	ParseParamRefHook p_paramref_hook;
	CoerceParamHook p_coerce_param_hook;
	void	   *p_ref_hook_state;	/* common passthrough link for above */
};

/* Support for parser_errposition_callback function */
typedef struct ParseCallbackState
{
	ParseState *pstate;
	int			location;
	ErrorContextCallback errcontext;
} ParseCallbackState;


extern ParseState *make_parsestate(ParseState *parentParseState);
extern void free_parsestate(ParseState *pstate);
extern int	parser_errposition(ParseState *pstate, int location);

extern void setup_parser_errposition_callback(ParseCallbackState *pcbstate,
								  ParseState *pstate, int location);
extern void cancel_parser_errposition_callback(ParseCallbackState *pcbstate);

extern Var *make_var(ParseState *pstate, RangeTblEntry *rte, int attrno,
		 int location);
extern Oid	transformArrayType(Oid arrayType);
extern ArrayRef *transformArraySubscripts(ParseState *pstate,
						 Node *arrayBase,
						 Oid arrayType,
						 Oid elementType,
						 int32 elementTypMod,
						 List *indirection,
						 Node *assignFrom);
extern Const *make_const(ParseState *pstate, Value *value, int location);

#endif   /* PARSE_NODE_H */