/*------------------------------------------------------------------------- * * parse_node.h * Internal definitions for parser * * * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * src/include/parser/parse_node.h * *------------------------------------------------------------------------- */ #ifndef PARSE_NODE_H #define PARSE_NODE_H #include "nodes/parsenodes.h" #include "utils/relcache.h" /* * Expression kinds distinguished by transformExpr(). Many of these are not * semantically distinct so far as expression transformation goes; rather, * we distinguish them so that context-specific error messages can be printed. * * Note: EXPR_KIND_OTHER is not used in the core code, but is left for use * by extension code that might need to call transformExpr(). The core code * will not enforce any context-driven restrictions on EXPR_KIND_OTHER * expressions, so the caller would have to check for sub-selects, aggregates, * and window functions if those need to be disallowed. */ typedef enum ParseExprKind { EXPR_KIND_NONE = 0, /* "not in an expression" */ EXPR_KIND_OTHER, /* reserved for extensions */ EXPR_KIND_JOIN_ON, /* JOIN ON */ EXPR_KIND_JOIN_USING, /* JOIN USING */ EXPR_KIND_FROM_SUBSELECT, /* sub-SELECT in FROM clause */ EXPR_KIND_FROM_FUNCTION, /* function in FROM clause */ EXPR_KIND_WHERE, /* WHERE */ EXPR_KIND_HAVING, /* HAVING */ EXPR_KIND_FILTER, /* FILTER */ EXPR_KIND_WINDOW_PARTITION, /* window definition PARTITION BY */ EXPR_KIND_WINDOW_ORDER, /* window definition ORDER BY */ EXPR_KIND_WINDOW_FRAME_RANGE, /* window frame clause with RANGE */ EXPR_KIND_WINDOW_FRAME_ROWS, /* window frame clause with ROWS */ EXPR_KIND_SELECT_TARGET, /* SELECT target list item */ EXPR_KIND_INSERT_TARGET, /* INSERT target list item */ EXPR_KIND_UPDATE_SOURCE, /* UPDATE assignment source item */ EXPR_KIND_UPDATE_TARGET, /* UPDATE assignment target item */ EXPR_KIND_GROUP_BY, /* GROUP BY */ EXPR_KIND_ORDER_BY, /* ORDER BY */ EXPR_KIND_DISTINCT_ON, /* DISTINCT ON */ EXPR_KIND_LIMIT, /* LIMIT */ EXPR_KIND_OFFSET, /* OFFSET */ EXPR_KIND_RETURNING, /* RETURNING */ EXPR_KIND_VALUES, /* VALUES */ EXPR_KIND_CHECK_CONSTRAINT, /* CHECK constraint for a table */ EXPR_KIND_DOMAIN_CHECK, /* CHECK constraint for a domain */ EXPR_KIND_COLUMN_DEFAULT, /* default value for a table column */ EXPR_KIND_FUNCTION_DEFAULT, /* default parameter value for function */ EXPR_KIND_INDEX_EXPRESSION, /* index expression */ EXPR_KIND_INDEX_PREDICATE, /* index predicate */ EXPR_KIND_ALTER_COL_TRANSFORM, /* transform expr in ALTER COLUMN TYPE */ EXPR_KIND_EXECUTE_PARAMETER, /* parameter value in EXECUTE */ EXPR_KIND_TRIGGER_WHEN, /* WHEN condition in CREATE TRIGGER */ EXPR_KIND_POLICY /* USING or WITH CHECK expr in policy */ } ParseExprKind; /* * 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_namespace: list of ParseNamespaceItems that represents the current * namespace for table and column lookup. (The RTEs listed here may be just * a subset of the whole rtable. See ParseNamespaceItem comments below.) * * p_lateral_active: TRUE if we are currently parsing a LATERAL subexpression * of this parse level. This makes p_lateral_only namespace items visible, * whereas they are not visible when p_lateral_active is FALSE. * * p_ctenamespace: list of CommonTableExprs (WITH items) that are visible * at the moment. This is entirely different from p_namespace because a CTE * is not an RTE, rather "visibility" means you could make an RTE from it. * * 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_namespace; /* currently-referenceable RTEs (List of * ParseNamespaceItem) */ bool p_lateral_active; /* p_lateral_only items visible? */ 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 */ ParseExprKind p_expr_kind; /* what kind of expression we're parsing */ int p_next_resno; /* next targetlist resno to assign */ List *p_multiassign_exprs; /* junk tlist entries for multiassign */ 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_hasModifyingCTE; bool p_is_insert; 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 */ }; /* * An element of a namespace list. * * Namespace items with p_rel_visible set define which RTEs are accessible by * qualified names, while those with p_cols_visible set define which RTEs are * accessible by unqualified names. These sets are different because a JOIN * without an alias does not hide the contained tables (so they must be * visible for qualified references) but it does hide their columns * (unqualified references to the columns refer to the JOIN, not the member * tables, so we must not complain that such a reference is ambiguous). * Various special RTEs such as NEW/OLD for rules may also appear with only * one flag set. * * While processing the FROM clause, namespace items may appear with * p_lateral_only set, meaning they are visible only to LATERAL * subexpressions. (The pstate's p_lateral_active flag tells whether we are * inside such a subexpression at the moment.) If p_lateral_ok is not set, * it's an error to actually use such a namespace item. One might think it * would be better to just exclude such items from visibility, but the wording * of SQL:2008 requires us to do it this way. We also use p_lateral_ok to * forbid LATERAL references to an UPDATE/DELETE target table. * * At no time should a namespace list contain two entries that conflict * according to the rules in checkNameSpaceConflicts; but note that those * are more complicated than "must have different alias names", so in practice * code searching a namespace list has to check for ambiguous references. */ typedef struct ParseNamespaceItem { RangeTblEntry *p_rte; /* The relation's rangetable entry */ bool p_rel_visible; /* Relation name is visible? */ bool p_cols_visible; /* Column names visible as unqualified refs? */ bool p_lateral_only; /* Is only visible to LATERAL expressions? */ bool p_lateral_ok; /* If so, does join type allow use? */ } ParseNamespaceItem; /* Support for parser_errposition_callback function */ typedef struct ParseCallbackState { ParseState *pstate; int location; ErrorContextCallback errcallback; } 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, int32 *arrayTypmod); extern ArrayRef *transformArraySubscripts(ParseState *pstate, Node *arrayBase, Oid arrayType, Oid elementType, int32 arrayTypMod, List *indirection, Node *assignFrom); extern Const *make_const(ParseState *pstate, Value *value, int location); #endif /* PARSE_NODE_H */