/*------------------------------------------------------------------------- * * parse_node.h * Internal definitions for parser * * * Portions Copyright (c) 1996-2024, 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/queryenvironment.h" #include "utils/relcache.h" /* Forward references for some structs declared below */ typedef struct ParseState ParseState; typedef struct ParseNamespaceItem ParseNamespaceItem; typedef struct ParseNamespaceColumn ParseNamespaceColumn; /* * 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, * window functions, SRFs, etc 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_WINDOW_FRAME_GROUPS, /* window frame clause with GROUPS */ 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_MERGE_WHEN, /* MERGE WHEN [NOT] MATCHED condition */ 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 in INSERT/UPDATE/DELETE */ EXPR_KIND_MERGE_RETURNING, /* RETURNING in MERGE */ EXPR_KIND_VALUES, /* VALUES */ EXPR_KIND_VALUES_SINGLE, /* single-row VALUES (in INSERT only) */ 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_STATS_EXPRESSION, /* extended statistics expression */ 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 */ EXPR_KIND_PARTITION_BOUND, /* partition bound expression */ EXPR_KIND_PARTITION_EXPRESSION, /* PARTITION BY expression */ EXPR_KIND_CALL_ARGUMENT, /* procedure argument in CALL */ EXPR_KIND_COPY_WHERE, /* WHERE condition in COPY FROM */ EXPR_KIND_GENERATED_COLUMN, /* generation expression for a column */ EXPR_KIND_CYCLE_MARK, /* cycle mark value */ } ParseExprKind; /* * Function signatures for parser hooks */ 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_rteperminfos: list of RTEPermissionInfo containing an entry corresponding * to each RTE_RELATION entry in p_rtable. * * 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_nullingrels: list of Bitmapsets associated with p_rtable entries, each * containing the set of outer-join RTE indexes that can null that relation * at the current point in the parse tree. This is one-for-one with p_rtable, * but may be shorter than p_rtable, in which case the missing entries are * implicitly empty (NULL). That rule allows us to save work when the query * contains no outer 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_target_relation: target relation, if query is INSERT/UPDATE/DELETE/MERGE * * p_target_nsitem: target relation's ParseNamespaceItem. * * p_is_insert: true to process assignment expressions like INSERT, false * to process them like UPDATE. (Note this can change intra-statement, for * cases like INSERT ON CONFLICT UPDATE.) * * 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. * * p_expr_kind: kind of expression we're currently parsing, as per enum above; * EXPR_KIND_NONE when not in an expression. * * p_next_resno: next TargetEntry.resno to assign, starting from 1. * * p_multiassign_exprs: partially-processed MultiAssignRef source expressions. * * p_locking_clause: query's FOR UPDATE/FOR SHARE clause, if any. * * p_locked_from_parent: true if parent query level applies FOR UPDATE/SHARE * to this subquery as a whole. * * p_resolve_unknowns: resolve unknown-type SELECT output columns as type TEXT * (this is true by default). * * p_hasAggs, p_hasWindowFuncs, etc: true if we've found any of the indicated * constructs in the query. * * p_last_srf: the set-returning FuncExpr or OpExpr most recently found in * the query, or NULL if none. * * p_pre_columnref_hook, etc: optional parser hook functions for modifying the * interpretation of ColumnRefs and ParamRefs. * * p_ref_hook_state: passthrough state for the parser hook functions. */ struct ParseState { ParseState *parentParseState; /* stack link */ const char *p_sourcetext; /* source text, or NULL if not available */ List *p_rtable; /* range table so far */ List *p_rteperminfos; /* list of RTEPermissionInfo nodes for each * RTE_RELATION entry in rtable */ List *p_joinexprs; /* JoinExprs for RTE_JOIN p_rtable entries */ List *p_nullingrels; /* Bitmapsets showing nulling outer joins */ 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 */ Relation p_target_relation; /* INSERT/UPDATE/DELETE/MERGE target rel */ ParseNamespaceItem *p_target_nsitem; /* target rel's NSItem, or NULL */ bool p_is_insert; /* process assignment like INSERT not UPDATE */ 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 */ bool p_locked_from_parent; /* parent has marked this subquery * with FOR UPDATE/FOR SHARE */ bool p_resolve_unknowns; /* resolve unknown-type SELECT outputs as * type text */ QueryEnvironment *p_queryEnv; /* curr env, incl refs to enclosing env */ /* Flags telling about things found in the query: */ bool p_hasAggs; bool p_hasWindowFuncs; bool p_hasTargetSRFs; bool p_hasSubLinks; bool p_hasModifyingCTE; Node *p_last_srf; /* most recent set-returning func/op found */ /* * 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. * * p_names contains the table name and column names exposed by this nsitem. * (Typically it's equal to p_rte->eref, but for a JOIN USING alias it's * equal to p_rte->join_using_alias. Since the USING columns will be the * join's first N columns, the net effect is just that we expose only those * join columns via this nsitem.) * * p_rte and p_rtindex link to the underlying rangetable entry, and * p_perminfo to the entry in rteperminfos. * * The p_nscolumns array contains info showing how to construct Vars * referencing the names appearing in the p_names->colnames 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). * Conversely, a subquery without an alias does not hide the columns selected * by the subquery, but it does hide the auto-generated relation name (so the * subquery columns are visible for unqualified references only). 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. */ struct ParseNamespaceItem { Alias *p_names; /* Table and column names */ RangeTblEntry *p_rte; /* The relation's rangetable entry */ int p_rtindex; /* The relation's index in the rangetable */ RTEPermissionInfo *p_perminfo; /* The relation's rteperminfos entry */ /* array of same length as p_names->colnames: */ ParseNamespaceColumn *p_nscolumns; /* per-column data */ 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? */ }; /* * Data about one column of a ParseNamespaceItem. * * We track the info needed to construct a Var referencing the column * (but only for user-defined columns; system column references and * whole-row references are handled separately). * * p_varno and p_varattno identify the semantic referent, which is a * base-relation column unless the reference is to a join USING column that * isn't semantically equivalent to either join input column (because it is a * FULL join or the input column requires a type coercion). In those cases * p_varno and p_varattno refer to the JOIN RTE. * * p_varnosyn and p_varattnosyn are either identical to p_varno/p_varattno, * or they specify the column's position in an aliased JOIN RTE that hides * the semantic referent RTE's refname. (That could be either the JOIN RTE * in which this ParseNamespaceColumn entry exists, or some lower join level.) * * If an RTE contains a dropped column, its ParseNamespaceColumn struct * is all-zeroes. (Conventionally, test for p_varno == 0 to detect this.) */ struct ParseNamespaceColumn { Index p_varno; /* rangetable index */ AttrNumber p_varattno; /* attribute number of the column */ Oid p_vartype; /* pg_type OID */ int32 p_vartypmod; /* type modifier value */ Oid p_varcollid; /* OID of collation, or InvalidOid */ Index p_varnosyn; /* rangetable index of syntactic referent */ AttrNumber p_varattnosyn; /* attribute number of syntactic referent */ bool p_dontexpand; /* not included in star expansion */ }; /* 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 void transformContainerType(Oid *containerType, int32 *containerTypmod); extern SubscriptingRef *transformContainerSubscripts(ParseState *pstate, Node *containerBase, Oid containerType, int32 containerTypMod, List *indirection, bool isAssignment); extern Const *make_const(ParseState *pstate, A_Const *aconst); #endif /* PARSE_NODE_H */