1 /*------------------------------------------------------------------------- 2 * 3 * parse_node.h 4 * Internal definitions for parser 5 * 6 * 7 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group 8 * Portions Copyright (c) 1994, Regents of the University of California 9 * 10 * src/include/parser/parse_node.h 11 * 12 *------------------------------------------------------------------------- 13 */ 14 #ifndef PARSE_NODE_H 15 #define PARSE_NODE_H 16 17 #include "nodes/parsenodes.h" 18 #include "utils/queryenvironment.h" 19 #include "utils/relcache.h" 20 21 22 /* Forward references for some structs declared below */ 23 typedef struct ParseState ParseState; 24 typedef struct ParseNamespaceItem ParseNamespaceItem; 25 typedef struct ParseNamespaceColumn ParseNamespaceColumn; 26 27 /* 28 * Expression kinds distinguished by transformExpr(). Many of these are not 29 * semantically distinct so far as expression transformation goes; rather, 30 * we distinguish them so that context-specific error messages can be printed. 31 * 32 * Note: EXPR_KIND_OTHER is not used in the core code, but is left for use 33 * by extension code that might need to call transformExpr(). The core code 34 * will not enforce any context-driven restrictions on EXPR_KIND_OTHER 35 * expressions, so the caller would have to check for sub-selects, aggregates, 36 * window functions, SRFs, etc if those need to be disallowed. 37 */ 38 typedef enum ParseExprKind 39 { 40 EXPR_KIND_NONE = 0, /* "not in an expression" */ 41 EXPR_KIND_OTHER, /* reserved for extensions */ 42 EXPR_KIND_JOIN_ON, /* JOIN ON */ 43 EXPR_KIND_JOIN_USING, /* JOIN USING */ 44 EXPR_KIND_FROM_SUBSELECT, /* sub-SELECT in FROM clause */ 45 EXPR_KIND_FROM_FUNCTION, /* function in FROM clause */ 46 EXPR_KIND_WHERE, /* WHERE */ 47 EXPR_KIND_HAVING, /* HAVING */ 48 EXPR_KIND_FILTER, /* FILTER */ 49 EXPR_KIND_WINDOW_PARTITION, /* window definition PARTITION BY */ 50 EXPR_KIND_WINDOW_ORDER, /* window definition ORDER BY */ 51 EXPR_KIND_WINDOW_FRAME_RANGE, /* window frame clause with RANGE */ 52 EXPR_KIND_WINDOW_FRAME_ROWS, /* window frame clause with ROWS */ 53 EXPR_KIND_WINDOW_FRAME_GROUPS, /* window frame clause with GROUPS */ 54 EXPR_KIND_SELECT_TARGET, /* SELECT target list item */ 55 EXPR_KIND_INSERT_TARGET, /* INSERT target list item */ 56 EXPR_KIND_UPDATE_SOURCE, /* UPDATE assignment source item */ 57 EXPR_KIND_UPDATE_TARGET, /* UPDATE assignment target item */ 58 EXPR_KIND_GROUP_BY, /* GROUP BY */ 59 EXPR_KIND_ORDER_BY, /* ORDER BY */ 60 EXPR_KIND_DISTINCT_ON, /* DISTINCT ON */ 61 EXPR_KIND_LIMIT, /* LIMIT */ 62 EXPR_KIND_OFFSET, /* OFFSET */ 63 EXPR_KIND_RETURNING, /* RETURNING */ 64 EXPR_KIND_VALUES, /* VALUES */ 65 EXPR_KIND_VALUES_SINGLE, /* single-row VALUES (in INSERT only) */ 66 EXPR_KIND_CHECK_CONSTRAINT, /* CHECK constraint for a table */ 67 EXPR_KIND_DOMAIN_CHECK, /* CHECK constraint for a domain */ 68 EXPR_KIND_COLUMN_DEFAULT, /* default value for a table column */ 69 EXPR_KIND_FUNCTION_DEFAULT, /* default parameter value for function */ 70 EXPR_KIND_INDEX_EXPRESSION, /* index expression */ 71 EXPR_KIND_INDEX_PREDICATE, /* index predicate */ 72 EXPR_KIND_ALTER_COL_TRANSFORM, /* transform expr in ALTER COLUMN TYPE */ 73 EXPR_KIND_EXECUTE_PARAMETER, /* parameter value in EXECUTE */ 74 EXPR_KIND_TRIGGER_WHEN, /* WHEN condition in CREATE TRIGGER */ 75 EXPR_KIND_POLICY, /* USING or WITH CHECK expr in policy */ 76 EXPR_KIND_PARTITION_BOUND, /* partition bound expression */ 77 EXPR_KIND_PARTITION_EXPRESSION, /* PARTITION BY expression */ 78 EXPR_KIND_CALL_ARGUMENT, /* procedure argument in CALL */ 79 EXPR_KIND_COPY_WHERE, /* WHERE condition in COPY FROM */ 80 EXPR_KIND_GENERATED_COLUMN, /* generation expression for a column */ 81 } ParseExprKind; 82 83 84 /* 85 * Function signatures for parser hooks 86 */ 87 typedef Node *(*PreParseColumnRefHook) (ParseState *pstate, ColumnRef *cref); 88 typedef Node *(*PostParseColumnRefHook) (ParseState *pstate, ColumnRef *cref, Node *var); 89 typedef Node *(*ParseParamRefHook) (ParseState *pstate, ParamRef *pref); 90 typedef Node *(*CoerceParamHook) (ParseState *pstate, Param *param, 91 Oid targetTypeId, int32 targetTypeMod, 92 int location); 93 94 95 /* 96 * State information used during parse analysis 97 * 98 * parentParseState: NULL in a top-level ParseState. When parsing a subquery, 99 * links to current parse state of outer query. 100 * 101 * p_sourcetext: source string that generated the raw parsetree being 102 * analyzed, or NULL if not available. (The string is used only to 103 * generate cursor positions in error messages: we need it to convert 104 * byte-wise locations in parse structures to character-wise cursor 105 * positions.) 106 * 107 * p_rtable: list of RTEs that will become the rangetable of the query. 108 * Note that neither relname nor refname of these entries are necessarily 109 * unique; searching the rtable by name is a bad idea. 110 * 111 * p_joinexprs: list of JoinExpr nodes associated with p_rtable entries. 112 * This is one-for-one with p_rtable, but contains NULLs for non-join 113 * RTEs, and may be shorter than p_rtable if the last RTE(s) aren't joins. 114 * 115 * p_joinlist: list of join items (RangeTblRef and JoinExpr nodes) that 116 * will become the fromlist of the query's top-level FromExpr node. 117 * 118 * p_namespace: list of ParseNamespaceItems that represents the current 119 * namespace for table and column lookup. (The RTEs listed here may be just 120 * a subset of the whole rtable. See ParseNamespaceItem comments below.) 121 * 122 * p_lateral_active: true if we are currently parsing a LATERAL subexpression 123 * of this parse level. This makes p_lateral_only namespace items visible, 124 * whereas they are not visible when p_lateral_active is FALSE. 125 * 126 * p_ctenamespace: list of CommonTableExprs (WITH items) that are visible 127 * at the moment. This is entirely different from p_namespace because a CTE 128 * is not an RTE, rather "visibility" means you could make an RTE from it. 129 * 130 * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet 131 * visible due to scope rules. This is used to help improve error messages. 132 * 133 * p_parent_cte: CommonTableExpr that immediately contains the current query, 134 * if any. 135 * 136 * p_target_relation: target relation, if query is INSERT, UPDATE, or DELETE. 137 * 138 * p_target_nsitem: target relation's ParseNamespaceItem. 139 * 140 * p_is_insert: true to process assignment expressions like INSERT, false 141 * to process them like UPDATE. (Note this can change intra-statement, for 142 * cases like INSERT ON CONFLICT UPDATE.) 143 * 144 * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses. 145 * We collect these while transforming expressions and then transform them 146 * afterwards (so that any resjunk tlist items needed for the sort/group 147 * clauses end up at the end of the query tlist). A WindowDef's location in 148 * this list, counting from 1, is the winref number to use to reference it. 149 * 150 * p_expr_kind: kind of expression we're currently parsing, as per enum above; 151 * EXPR_KIND_NONE when not in an expression. 152 * 153 * p_next_resno: next TargetEntry.resno to assign, starting from 1. 154 * 155 * p_multiassign_exprs: partially-processed MultiAssignRef source expressions. 156 * 157 * p_locking_clause: query's FOR UPDATE/FOR SHARE clause, if any. 158 * 159 * p_locked_from_parent: true if parent query level applies FOR UPDATE/SHARE 160 * to this subquery as a whole. 161 * 162 * p_resolve_unknowns: resolve unknown-type SELECT output columns as type TEXT 163 * (this is true by default). 164 * 165 * p_hasAggs, p_hasWindowFuncs, etc: true if we've found any of the indicated 166 * constructs in the query. 167 * 168 * p_last_srf: the set-returning FuncExpr or OpExpr most recently found in 169 * the query, or NULL if none. 170 * 171 * p_pre_columnref_hook, etc: optional parser hook functions for modifying the 172 * interpretation of ColumnRefs and ParamRefs. 173 * 174 * p_ref_hook_state: passthrough state for the parser hook functions. 175 */ 176 struct ParseState 177 { 178 ParseState *parentParseState; /* stack link */ 179 const char *p_sourcetext; /* source text, or NULL if not available */ 180 List *p_rtable; /* range table so far */ 181 List *p_joinexprs; /* JoinExprs for RTE_JOIN p_rtable entries */ 182 List *p_joinlist; /* join items so far (will become FromExpr 183 * node's fromlist) */ 184 List *p_namespace; /* currently-referenceable RTEs (List of 185 * ParseNamespaceItem) */ 186 bool p_lateral_active; /* p_lateral_only items visible? */ 187 List *p_ctenamespace; /* current namespace for common table exprs */ 188 List *p_future_ctes; /* common table exprs not yet in namespace */ 189 CommonTableExpr *p_parent_cte; /* this query's containing CTE */ 190 Relation p_target_relation; /* INSERT/UPDATE/DELETE target rel */ 191 ParseNamespaceItem *p_target_nsitem; /* target rel's NSItem, or NULL */ 192 bool p_is_insert; /* process assignment like INSERT not UPDATE */ 193 List *p_windowdefs; /* raw representations of window clauses */ 194 ParseExprKind p_expr_kind; /* what kind of expression we're parsing */ 195 int p_next_resno; /* next targetlist resno to assign */ 196 List *p_multiassign_exprs; /* junk tlist entries for multiassign */ 197 List *p_locking_clause; /* raw FOR UPDATE/FOR SHARE info */ 198 bool p_locked_from_parent; /* parent has marked this subquery 199 * with FOR UPDATE/FOR SHARE */ 200 bool p_resolve_unknowns; /* resolve unknown-type SELECT outputs as 201 * type text */ 202 203 QueryEnvironment *p_queryEnv; /* curr env, incl refs to enclosing env */ 204 205 /* Flags telling about things found in the query: */ 206 bool p_hasAggs; 207 bool p_hasWindowFuncs; 208 bool p_hasTargetSRFs; 209 bool p_hasSubLinks; 210 bool p_hasModifyingCTE; 211 212 Node *p_last_srf; /* most recent set-returning func/op found */ 213 214 /* 215 * Optional hook functions for parser callbacks. These are null unless 216 * set up by the caller of make_parsestate. 217 */ 218 PreParseColumnRefHook p_pre_columnref_hook; 219 PostParseColumnRefHook p_post_columnref_hook; 220 ParseParamRefHook p_paramref_hook; 221 CoerceParamHook p_coerce_param_hook; 222 void *p_ref_hook_state; /* common passthrough link for above */ 223 }; 224 225 /* 226 * An element of a namespace list. 227 * 228 * The p_nscolumns array contains info showing how to construct Vars 229 * referencing corresponding elements of the RTE's colnames list. 230 * 231 * Namespace items with p_rel_visible set define which RTEs are accessible by 232 * qualified names, while those with p_cols_visible set define which RTEs are 233 * accessible by unqualified names. These sets are different because a JOIN 234 * without an alias does not hide the contained tables (so they must be 235 * visible for qualified references) but it does hide their columns 236 * (unqualified references to the columns refer to the JOIN, not the member 237 * tables, so we must not complain that such a reference is ambiguous). 238 * Various special RTEs such as NEW/OLD for rules may also appear with only 239 * one flag set. 240 * 241 * While processing the FROM clause, namespace items may appear with 242 * p_lateral_only set, meaning they are visible only to LATERAL 243 * subexpressions. (The pstate's p_lateral_active flag tells whether we are 244 * inside such a subexpression at the moment.) If p_lateral_ok is not set, 245 * it's an error to actually use such a namespace item. One might think it 246 * would be better to just exclude such items from visibility, but the wording 247 * of SQL:2008 requires us to do it this way. We also use p_lateral_ok to 248 * forbid LATERAL references to an UPDATE/DELETE target table. 249 * 250 * At no time should a namespace list contain two entries that conflict 251 * according to the rules in checkNameSpaceConflicts; but note that those 252 * are more complicated than "must have different alias names", so in practice 253 * code searching a namespace list has to check for ambiguous references. 254 */ 255 struct ParseNamespaceItem 256 { 257 RangeTblEntry *p_rte; /* The relation's rangetable entry */ 258 int p_rtindex; /* The relation's index in the rangetable */ 259 /* array of same length as p_rte->eref->colnames: */ 260 ParseNamespaceColumn *p_nscolumns; /* per-column data */ 261 bool p_rel_visible; /* Relation name is visible? */ 262 bool p_cols_visible; /* Column names visible as unqualified refs? */ 263 bool p_lateral_only; /* Is only visible to LATERAL expressions? */ 264 bool p_lateral_ok; /* If so, does join type allow use? */ 265 }; 266 267 /* 268 * Data about one column of a ParseNamespaceItem. 269 * 270 * We track the info needed to construct a Var referencing the column 271 * (but only for user-defined columns; system column references and 272 * whole-row references are handled separately). 273 * 274 * p_varno and p_varattno identify the semantic referent, which is a 275 * base-relation column unless the reference is to a join USING column that 276 * isn't semantically equivalent to either join input column (because it is a 277 * FULL join or the input column requires a type coercion). In those cases 278 * p_varno and p_varattno refer to the JOIN RTE. 279 * 280 * p_varnosyn and p_varattnosyn are either identical to p_varno/p_varattno, 281 * or they specify the column's position in an aliased JOIN RTE that hides 282 * the semantic referent RTE's refname. (That could be either the JOIN RTE 283 * in which this ParseNamespaceColumn entry exists, or some lower join level.) 284 * 285 * If an RTE contains a dropped column, its ParseNamespaceColumn struct 286 * is all-zeroes. (Conventionally, test for p_varno == 0 to detect this.) 287 */ 288 struct ParseNamespaceColumn 289 { 290 Index p_varno; /* rangetable index */ 291 AttrNumber p_varattno; /* attribute number of the column */ 292 Oid p_vartype; /* pg_type OID */ 293 int32 p_vartypmod; /* type modifier value */ 294 Oid p_varcollid; /* OID of collation, or InvalidOid */ 295 Index p_varnosyn; /* rangetable index of syntactic referent */ 296 AttrNumber p_varattnosyn; /* attribute number of syntactic referent */ 297 }; 298 299 /* Support for parser_errposition_callback function */ 300 typedef struct ParseCallbackState 301 { 302 ParseState *pstate; 303 int location; 304 ErrorContextCallback errcallback; 305 } ParseCallbackState; 306 307 308 extern ParseState *make_parsestate(ParseState *parentParseState); 309 extern void free_parsestate(ParseState *pstate); 310 extern int parser_errposition(ParseState *pstate, int location); 311 312 extern void setup_parser_errposition_callback(ParseCallbackState *pcbstate, 313 ParseState *pstate, int location); 314 extern void cancel_parser_errposition_callback(ParseCallbackState *pcbstate); 315 316 extern Oid transformContainerType(Oid *containerType, int32 *containerTypmod); 317 318 extern SubscriptingRef *transformContainerSubscripts(ParseState *pstate, 319 Node *containerBase, 320 Oid containerType, 321 Oid elementType, 322 int32 containerTypMod, 323 List *indirection, 324 Node *assignFrom); 325 extern Const *make_const(ParseState *pstate, Value *value, int location); 326 327 #endif /* PARSE_NODE_H */ 328