1 /*------------------------------------------------------------------------- 2 * 3 * parse_node.h 4 * Internal definitions for parser 5 * 6 * 7 * Portions Copyright (c) 1996-2019, 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 /* 23 * Expression kinds distinguished by transformExpr(). Many of these are not 24 * semantically distinct so far as expression transformation goes; rather, 25 * we distinguish them so that context-specific error messages can be printed. 26 * 27 * Note: EXPR_KIND_OTHER is not used in the core code, but is left for use 28 * by extension code that might need to call transformExpr(). The core code 29 * will not enforce any context-driven restrictions on EXPR_KIND_OTHER 30 * expressions, so the caller would have to check for sub-selects, aggregates, 31 * window functions, SRFs, etc if those need to be disallowed. 32 */ 33 typedef enum ParseExprKind 34 { 35 EXPR_KIND_NONE = 0, /* "not in an expression" */ 36 EXPR_KIND_OTHER, /* reserved for extensions */ 37 EXPR_KIND_JOIN_ON, /* JOIN ON */ 38 EXPR_KIND_JOIN_USING, /* JOIN USING */ 39 EXPR_KIND_FROM_SUBSELECT, /* sub-SELECT in FROM clause */ 40 EXPR_KIND_FROM_FUNCTION, /* function in FROM clause */ 41 EXPR_KIND_WHERE, /* WHERE */ 42 EXPR_KIND_HAVING, /* HAVING */ 43 EXPR_KIND_FILTER, /* FILTER */ 44 EXPR_KIND_WINDOW_PARTITION, /* window definition PARTITION BY */ 45 EXPR_KIND_WINDOW_ORDER, /* window definition ORDER BY */ 46 EXPR_KIND_WINDOW_FRAME_RANGE, /* window frame clause with RANGE */ 47 EXPR_KIND_WINDOW_FRAME_ROWS, /* window frame clause with ROWS */ 48 EXPR_KIND_WINDOW_FRAME_GROUPS, /* window frame clause with GROUPS */ 49 EXPR_KIND_SELECT_TARGET, /* SELECT target list item */ 50 EXPR_KIND_INSERT_TARGET, /* INSERT target list item */ 51 EXPR_KIND_UPDATE_SOURCE, /* UPDATE assignment source item */ 52 EXPR_KIND_UPDATE_TARGET, /* UPDATE assignment target item */ 53 EXPR_KIND_GROUP_BY, /* GROUP BY */ 54 EXPR_KIND_ORDER_BY, /* ORDER BY */ 55 EXPR_KIND_DISTINCT_ON, /* DISTINCT ON */ 56 EXPR_KIND_LIMIT, /* LIMIT */ 57 EXPR_KIND_OFFSET, /* OFFSET */ 58 EXPR_KIND_RETURNING, /* RETURNING */ 59 EXPR_KIND_VALUES, /* VALUES */ 60 EXPR_KIND_VALUES_SINGLE, /* single-row VALUES (in INSERT only) */ 61 EXPR_KIND_CHECK_CONSTRAINT, /* CHECK constraint for a table */ 62 EXPR_KIND_DOMAIN_CHECK, /* CHECK constraint for a domain */ 63 EXPR_KIND_COLUMN_DEFAULT, /* default value for a table column */ 64 EXPR_KIND_FUNCTION_DEFAULT, /* default parameter value for function */ 65 EXPR_KIND_INDEX_EXPRESSION, /* index expression */ 66 EXPR_KIND_INDEX_PREDICATE, /* index predicate */ 67 EXPR_KIND_ALTER_COL_TRANSFORM, /* transform expr in ALTER COLUMN TYPE */ 68 EXPR_KIND_EXECUTE_PARAMETER, /* parameter value in EXECUTE */ 69 EXPR_KIND_TRIGGER_WHEN, /* WHEN condition in CREATE TRIGGER */ 70 EXPR_KIND_POLICY, /* USING or WITH CHECK expr in policy */ 71 EXPR_KIND_PARTITION_BOUND, /* partition bound expression */ 72 EXPR_KIND_PARTITION_EXPRESSION, /* PARTITION BY expression */ 73 EXPR_KIND_CALL_ARGUMENT, /* procedure argument in CALL */ 74 EXPR_KIND_COPY_WHERE, /* WHERE condition in COPY FROM */ 75 EXPR_KIND_GENERATED_COLUMN, /* generation expression for a column */ 76 } ParseExprKind; 77 78 79 /* 80 * Function signatures for parser hooks 81 */ 82 typedef struct ParseState ParseState; 83 84 typedef Node *(*PreParseColumnRefHook) (ParseState *pstate, ColumnRef *cref); 85 typedef Node *(*PostParseColumnRefHook) (ParseState *pstate, ColumnRef *cref, Node *var); 86 typedef Node *(*ParseParamRefHook) (ParseState *pstate, ParamRef *pref); 87 typedef Node *(*CoerceParamHook) (ParseState *pstate, Param *param, 88 Oid targetTypeId, int32 targetTypeMod, 89 int location); 90 91 92 /* 93 * State information used during parse analysis 94 * 95 * parentParseState: NULL in a top-level ParseState. When parsing a subquery, 96 * links to current parse state of outer query. 97 * 98 * p_sourcetext: source string that generated the raw parsetree being 99 * analyzed, or NULL if not available. (The string is used only to 100 * generate cursor positions in error messages: we need it to convert 101 * byte-wise locations in parse structures to character-wise cursor 102 * positions.) 103 * 104 * p_rtable: list of RTEs that will become the rangetable of the query. 105 * Note that neither relname nor refname of these entries are necessarily 106 * unique; searching the rtable by name is a bad idea. 107 * 108 * p_joinexprs: list of JoinExpr nodes associated with p_rtable entries. 109 * This is one-for-one with p_rtable, but contains NULLs for non-join 110 * RTEs, and may be shorter than p_rtable if the last RTE(s) aren't joins. 111 * 112 * p_joinlist: list of join items (RangeTblRef and JoinExpr nodes) that 113 * will become the fromlist of the query's top-level FromExpr node. 114 * 115 * p_namespace: list of ParseNamespaceItems that represents the current 116 * namespace for table and column lookup. (The RTEs listed here may be just 117 * a subset of the whole rtable. See ParseNamespaceItem comments below.) 118 * 119 * p_lateral_active: true if we are currently parsing a LATERAL subexpression 120 * of this parse level. This makes p_lateral_only namespace items visible, 121 * whereas they are not visible when p_lateral_active is FALSE. 122 * 123 * p_ctenamespace: list of CommonTableExprs (WITH items) that are visible 124 * at the moment. This is entirely different from p_namespace because a CTE 125 * is not an RTE, rather "visibility" means you could make an RTE from it. 126 * 127 * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet 128 * visible due to scope rules. This is used to help improve error messages. 129 * 130 * p_parent_cte: CommonTableExpr that immediately contains the current query, 131 * if any. 132 * 133 * p_target_relation: target relation, if query is INSERT, UPDATE, or DELETE. 134 * 135 * p_target_rangetblentry: target relation's entry in the rtable list. 136 * 137 * p_is_insert: true to process assignment expressions like INSERT, false 138 * to process them like UPDATE. (Note this can change intra-statement, for 139 * cases like INSERT ON CONFLICT UPDATE.) 140 * 141 * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses. 142 * We collect these while transforming expressions and then transform them 143 * afterwards (so that any resjunk tlist items needed for the sort/group 144 * clauses end up at the end of the query tlist). A WindowDef's location in 145 * this list, counting from 1, is the winref number to use to reference it. 146 * 147 * p_expr_kind: kind of expression we're currently parsing, as per enum above; 148 * EXPR_KIND_NONE when not in an expression. 149 * 150 * p_next_resno: next TargetEntry.resno to assign, starting from 1. 151 * 152 * p_multiassign_exprs: partially-processed MultiAssignRef source expressions. 153 * 154 * p_locking_clause: query's FOR UPDATE/FOR SHARE clause, if any. 155 * 156 * p_locked_from_parent: true if parent query level applies FOR UPDATE/SHARE 157 * to this subquery as a whole. 158 * 159 * p_resolve_unknowns: resolve unknown-type SELECT output columns as type TEXT 160 * (this is true by default). 161 * 162 * p_hasAggs, p_hasWindowFuncs, etc: true if we've found any of the indicated 163 * constructs in the query. 164 * 165 * p_last_srf: the set-returning FuncExpr or OpExpr most recently found in 166 * the query, or NULL if none. 167 * 168 * p_pre_columnref_hook, etc: optional parser hook functions for modifying the 169 * interpretation of ColumnRefs and ParamRefs. 170 * 171 * p_ref_hook_state: passthrough state for the parser hook functions. 172 */ 173 struct ParseState 174 { 175 struct ParseState *parentParseState; /* stack link */ 176 const char *p_sourcetext; /* source text, or NULL if not available */ 177 List *p_rtable; /* range table so far */ 178 List *p_joinexprs; /* JoinExprs for RTE_JOIN p_rtable entries */ 179 List *p_joinlist; /* join items so far (will become FromExpr 180 * node's fromlist) */ 181 List *p_namespace; /* currently-referenceable RTEs (List of 182 * ParseNamespaceItem) */ 183 bool p_lateral_active; /* p_lateral_only items visible? */ 184 List *p_ctenamespace; /* current namespace for common table exprs */ 185 List *p_future_ctes; /* common table exprs not yet in namespace */ 186 CommonTableExpr *p_parent_cte; /* this query's containing CTE */ 187 Relation p_target_relation; /* INSERT/UPDATE/DELETE target rel */ 188 RangeTblEntry *p_target_rangetblentry; /* target rel's RTE */ 189 bool p_is_insert; /* process assignment like INSERT not UPDATE */ 190 List *p_windowdefs; /* raw representations of window clauses */ 191 ParseExprKind p_expr_kind; /* what kind of expression we're parsing */ 192 int p_next_resno; /* next targetlist resno to assign */ 193 List *p_multiassign_exprs; /* junk tlist entries for multiassign */ 194 List *p_locking_clause; /* raw FOR UPDATE/FOR SHARE info */ 195 bool p_locked_from_parent; /* parent has marked this subquery 196 * with FOR UPDATE/FOR SHARE */ 197 bool p_resolve_unknowns; /* resolve unknown-type SELECT outputs as 198 * type text */ 199 200 QueryEnvironment *p_queryEnv; /* curr env, incl refs to enclosing env */ 201 202 /* Flags telling about things found in the query: */ 203 bool p_hasAggs; 204 bool p_hasWindowFuncs; 205 bool p_hasTargetSRFs; 206 bool p_hasSubLinks; 207 bool p_hasModifyingCTE; 208 209 Node *p_last_srf; /* most recent set-returning func/op found */ 210 211 /* 212 * Optional hook functions for parser callbacks. These are null unless 213 * set up by the caller of make_parsestate. 214 */ 215 PreParseColumnRefHook p_pre_columnref_hook; 216 PostParseColumnRefHook p_post_columnref_hook; 217 ParseParamRefHook p_paramref_hook; 218 CoerceParamHook p_coerce_param_hook; 219 void *p_ref_hook_state; /* common passthrough link for above */ 220 }; 221 222 /* 223 * An element of a namespace list. 224 * 225 * Namespace items with p_rel_visible set define which RTEs are accessible by 226 * qualified names, while those with p_cols_visible set define which RTEs are 227 * accessible by unqualified names. These sets are different because a JOIN 228 * without an alias does not hide the contained tables (so they must be 229 * visible for qualified references) but it does hide their columns 230 * (unqualified references to the columns refer to the JOIN, not the member 231 * tables, so we must not complain that such a reference is ambiguous). 232 * Various special RTEs such as NEW/OLD for rules may also appear with only 233 * one flag set. 234 * 235 * While processing the FROM clause, namespace items may appear with 236 * p_lateral_only set, meaning they are visible only to LATERAL 237 * subexpressions. (The pstate's p_lateral_active flag tells whether we are 238 * inside such a subexpression at the moment.) If p_lateral_ok is not set, 239 * it's an error to actually use such a namespace item. One might think it 240 * would be better to just exclude such items from visibility, but the wording 241 * of SQL:2008 requires us to do it this way. We also use p_lateral_ok to 242 * forbid LATERAL references to an UPDATE/DELETE target table. 243 * 244 * At no time should a namespace list contain two entries that conflict 245 * according to the rules in checkNameSpaceConflicts; but note that those 246 * are more complicated than "must have different alias names", so in practice 247 * code searching a namespace list has to check for ambiguous references. 248 */ 249 typedef struct ParseNamespaceItem 250 { 251 RangeTblEntry *p_rte; /* The relation's rangetable entry */ 252 bool p_rel_visible; /* Relation name is visible? */ 253 bool p_cols_visible; /* Column names visible as unqualified refs? */ 254 bool p_lateral_only; /* Is only visible to LATERAL expressions? */ 255 bool p_lateral_ok; /* If so, does join type allow use? */ 256 } ParseNamespaceItem; 257 258 /* Support for parser_errposition_callback function */ 259 typedef struct ParseCallbackState 260 { 261 ParseState *pstate; 262 int location; 263 ErrorContextCallback errcallback; 264 } ParseCallbackState; 265 266 267 extern ParseState *make_parsestate(ParseState *parentParseState); 268 extern void free_parsestate(ParseState *pstate); 269 extern int parser_errposition(ParseState *pstate, int location); 270 271 extern void setup_parser_errposition_callback(ParseCallbackState *pcbstate, 272 ParseState *pstate, int location); 273 extern void cancel_parser_errposition_callback(ParseCallbackState *pcbstate); 274 275 extern Var *make_var(ParseState *pstate, RangeTblEntry *rte, int attrno, 276 int location); 277 extern Oid transformContainerType(Oid *containerType, int32 *containerTypmod); 278 279 extern SubscriptingRef *transformContainerSubscripts(ParseState *pstate, 280 Node *containerBase, 281 Oid containerType, 282 Oid elementType, 283 int32 containerTypMod, 284 List *indirection, 285 Node *assignFrom); 286 extern Const *make_const(ParseState *pstate, Value *value, int location); 287 288 #endif /* PARSE_NODE_H */ 289