1 /*------------------------------------------------------------------------- 2 * 3 * parse_node.h 4 * Internal definitions for parser 5 * 6 * 7 * Portions Copyright (c) 1996-2017, 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_SELECT_TARGET, /* SELECT target list item */ 49 EXPR_KIND_INSERT_TARGET, /* INSERT target list item */ 50 EXPR_KIND_UPDATE_SOURCE, /* UPDATE assignment source item */ 51 EXPR_KIND_UPDATE_TARGET, /* UPDATE assignment target item */ 52 EXPR_KIND_GROUP_BY, /* GROUP BY */ 53 EXPR_KIND_ORDER_BY, /* ORDER BY */ 54 EXPR_KIND_DISTINCT_ON, /* DISTINCT ON */ 55 EXPR_KIND_LIMIT, /* LIMIT */ 56 EXPR_KIND_OFFSET, /* OFFSET */ 57 EXPR_KIND_RETURNING, /* RETURNING */ 58 EXPR_KIND_VALUES, /* VALUES */ 59 EXPR_KIND_VALUES_SINGLE, /* single-row VALUES (in INSERT only) */ 60 EXPR_KIND_CHECK_CONSTRAINT, /* CHECK constraint for a table */ 61 EXPR_KIND_DOMAIN_CHECK, /* CHECK constraint for a domain */ 62 EXPR_KIND_COLUMN_DEFAULT, /* default value for a table column */ 63 EXPR_KIND_FUNCTION_DEFAULT, /* default parameter value for function */ 64 EXPR_KIND_INDEX_EXPRESSION, /* index expression */ 65 EXPR_KIND_INDEX_PREDICATE, /* index predicate */ 66 EXPR_KIND_ALTER_COL_TRANSFORM, /* transform expr in ALTER COLUMN TYPE */ 67 EXPR_KIND_EXECUTE_PARAMETER, /* parameter value in EXECUTE */ 68 EXPR_KIND_TRIGGER_WHEN, /* WHEN condition in CREATE TRIGGER */ 69 EXPR_KIND_POLICY, /* USING or WITH CHECK expr in policy */ 70 EXPR_KIND_PARTITION_EXPRESSION /* PARTITION BY expression */ 71 } ParseExprKind; 72 73 74 /* 75 * Function signatures for parser hooks 76 */ 77 typedef struct ParseState ParseState; 78 79 typedef Node *(*PreParseColumnRefHook) (ParseState *pstate, ColumnRef *cref); 80 typedef Node *(*PostParseColumnRefHook) (ParseState *pstate, ColumnRef *cref, Node *var); 81 typedef Node *(*ParseParamRefHook) (ParseState *pstate, ParamRef *pref); 82 typedef Node *(*CoerceParamHook) (ParseState *pstate, Param *param, 83 Oid targetTypeId, int32 targetTypeMod, 84 int location); 85 86 87 /* 88 * State information used during parse analysis 89 * 90 * parentParseState: NULL in a top-level ParseState. When parsing a subquery, 91 * links to current parse state of outer query. 92 * 93 * p_sourcetext: source string that generated the raw parsetree being 94 * analyzed, or NULL if not available. (The string is used only to 95 * generate cursor positions in error messages: we need it to convert 96 * byte-wise locations in parse structures to character-wise cursor 97 * positions.) 98 * 99 * p_rtable: list of RTEs that will become the rangetable of the query. 100 * Note that neither relname nor refname of these entries are necessarily 101 * unique; searching the rtable by name is a bad idea. 102 * 103 * p_joinexprs: list of JoinExpr nodes associated with p_rtable entries. 104 * This is one-for-one with p_rtable, but contains NULLs for non-join 105 * RTEs, and may be shorter than p_rtable if the last RTE(s) aren't joins. 106 * 107 * p_joinlist: list of join items (RangeTblRef and JoinExpr nodes) that 108 * will become the fromlist of the query's top-level FromExpr node. 109 * 110 * p_namespace: list of ParseNamespaceItems that represents the current 111 * namespace for table and column lookup. (The RTEs listed here may be just 112 * a subset of the whole rtable. See ParseNamespaceItem comments below.) 113 * 114 * p_lateral_active: TRUE if we are currently parsing a LATERAL subexpression 115 * of this parse level. This makes p_lateral_only namespace items visible, 116 * whereas they are not visible when p_lateral_active is FALSE. 117 * 118 * p_ctenamespace: list of CommonTableExprs (WITH items) that are visible 119 * at the moment. This is entirely different from p_namespace because a CTE 120 * is not an RTE, rather "visibility" means you could make an RTE from it. 121 * 122 * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet 123 * visible due to scope rules. This is used to help improve error messages. 124 * 125 * p_parent_cte: CommonTableExpr that immediately contains the current query, 126 * if any. 127 * 128 * p_target_relation: target relation, if query is INSERT, UPDATE, or DELETE. 129 * 130 * p_target_rangetblentry: target relation's entry in the rtable list. 131 * 132 * p_is_insert: true to process assignment expressions like INSERT, false 133 * to process them like UPDATE. (Note this can change intra-statement, for 134 * cases like INSERT ON CONFLICT UPDATE.) 135 * 136 * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses. 137 * We collect these while transforming expressions and then transform them 138 * afterwards (so that any resjunk tlist items needed for the sort/group 139 * clauses end up at the end of the query tlist). A WindowDef's location in 140 * this list, counting from 1, is the winref number to use to reference it. 141 * 142 * p_expr_kind: kind of expression we're currently parsing, as per enum above; 143 * EXPR_KIND_NONE when not in an expression. 144 * 145 * p_next_resno: next TargetEntry.resno to assign, starting from 1. 146 * 147 * p_multiassign_exprs: partially-processed MultiAssignRef source expressions. 148 * 149 * p_locking_clause: query's FOR UPDATE/FOR SHARE clause, if any. 150 * 151 * p_locked_from_parent: true if parent query level applies FOR UPDATE/SHARE 152 * to this subquery as a whole. 153 * 154 * p_resolve_unknowns: resolve unknown-type SELECT output columns as type TEXT 155 * (this is true by default). 156 * 157 * p_hasAggs, p_hasWindowFuncs, etc: true if we've found any of the indicated 158 * constructs in the query. 159 * 160 * p_last_srf: the set-returning FuncExpr or OpExpr most recently found in 161 * the query, or NULL if none. 162 * 163 * p_pre_columnref_hook, etc: optional parser hook functions for modifying the 164 * interpretation of ColumnRefs and ParamRefs. 165 * 166 * p_ref_hook_state: passthrough state for the parser hook functions. 167 */ 168 struct ParseState 169 { 170 struct ParseState *parentParseState; /* stack link */ 171 const char *p_sourcetext; /* source text, or NULL if not available */ 172 List *p_rtable; /* range table so far */ 173 List *p_joinexprs; /* JoinExprs for RTE_JOIN p_rtable entries */ 174 List *p_joinlist; /* join items so far (will become FromExpr 175 * node's fromlist) */ 176 List *p_namespace; /* currently-referenceable RTEs (List of 177 * ParseNamespaceItem) */ 178 bool p_lateral_active; /* p_lateral_only items visible? */ 179 List *p_ctenamespace; /* current namespace for common table exprs */ 180 List *p_future_ctes; /* common table exprs not yet in namespace */ 181 CommonTableExpr *p_parent_cte; /* this query's containing CTE */ 182 Relation p_target_relation; /* INSERT/UPDATE/DELETE target rel */ 183 RangeTblEntry *p_target_rangetblentry; /* target rel's RTE */ 184 bool p_is_insert; /* process assignment like INSERT not UPDATE */ 185 List *p_windowdefs; /* raw representations of window clauses */ 186 ParseExprKind p_expr_kind; /* what kind of expression we're parsing */ 187 int p_next_resno; /* next targetlist resno to assign */ 188 List *p_multiassign_exprs; /* junk tlist entries for multiassign */ 189 List *p_locking_clause; /* raw FOR UPDATE/FOR SHARE info */ 190 bool p_locked_from_parent; /* parent has marked this subquery 191 * with FOR UPDATE/FOR SHARE */ 192 bool p_resolve_unknowns; /* resolve unknown-type SELECT outputs as 193 * type text */ 194 195 QueryEnvironment *p_queryEnv; /* curr env, incl refs to enclosing env */ 196 197 /* Flags telling about things found in the query: */ 198 bool p_hasAggs; 199 bool p_hasWindowFuncs; 200 bool p_hasTargetSRFs; 201 bool p_hasSubLinks; 202 bool p_hasModifyingCTE; 203 204 Node *p_last_srf; /* most recent set-returning func/op found */ 205 206 /* 207 * Optional hook functions for parser callbacks. These are null unless 208 * set up by the caller of make_parsestate. 209 */ 210 PreParseColumnRefHook p_pre_columnref_hook; 211 PostParseColumnRefHook p_post_columnref_hook; 212 ParseParamRefHook p_paramref_hook; 213 CoerceParamHook p_coerce_param_hook; 214 void *p_ref_hook_state; /* common passthrough link for above */ 215 }; 216 217 /* 218 * An element of a namespace list. 219 * 220 * Namespace items with p_rel_visible set define which RTEs are accessible by 221 * qualified names, while those with p_cols_visible set define which RTEs are 222 * accessible by unqualified names. These sets are different because a JOIN 223 * without an alias does not hide the contained tables (so they must be 224 * visible for qualified references) but it does hide their columns 225 * (unqualified references to the columns refer to the JOIN, not the member 226 * tables, so we must not complain that such a reference is ambiguous). 227 * Various special RTEs such as NEW/OLD for rules may also appear with only 228 * one flag set. 229 * 230 * While processing the FROM clause, namespace items may appear with 231 * p_lateral_only set, meaning they are visible only to LATERAL 232 * subexpressions. (The pstate's p_lateral_active flag tells whether we are 233 * inside such a subexpression at the moment.) If p_lateral_ok is not set, 234 * it's an error to actually use such a namespace item. One might think it 235 * would be better to just exclude such items from visibility, but the wording 236 * of SQL:2008 requires us to do it this way. We also use p_lateral_ok to 237 * forbid LATERAL references to an UPDATE/DELETE target table. 238 * 239 * At no time should a namespace list contain two entries that conflict 240 * according to the rules in checkNameSpaceConflicts; but note that those 241 * are more complicated than "must have different alias names", so in practice 242 * code searching a namespace list has to check for ambiguous references. 243 */ 244 typedef struct ParseNamespaceItem 245 { 246 RangeTblEntry *p_rte; /* The relation's rangetable entry */ 247 bool p_rel_visible; /* Relation name is visible? */ 248 bool p_cols_visible; /* Column names visible as unqualified refs? */ 249 bool p_lateral_only; /* Is only visible to LATERAL expressions? */ 250 bool p_lateral_ok; /* If so, does join type allow use? */ 251 } ParseNamespaceItem; 252 253 /* Support for parser_errposition_callback function */ 254 typedef struct ParseCallbackState 255 { 256 ParseState *pstate; 257 int location; 258 ErrorContextCallback errcallback; 259 } ParseCallbackState; 260 261 262 extern ParseState *make_parsestate(ParseState *parentParseState); 263 extern void free_parsestate(ParseState *pstate); 264 extern int parser_errposition(ParseState *pstate, int location); 265 266 extern void setup_parser_errposition_callback(ParseCallbackState *pcbstate, 267 ParseState *pstate, int location); 268 extern void cancel_parser_errposition_callback(ParseCallbackState *pcbstate); 269 270 extern Var *make_var(ParseState *pstate, RangeTblEntry *rte, int attrno, 271 int location); 272 extern Oid transformArrayType(Oid *arrayType, int32 *arrayTypmod); 273 extern ArrayRef *transformArraySubscripts(ParseState *pstate, 274 Node *arrayBase, 275 Oid arrayType, 276 Oid elementType, 277 int32 arrayTypMod, 278 List *indirection, 279 Node *assignFrom); 280 extern Const *make_const(ParseState *pstate, Value *value, int location); 281 282 #endif /* PARSE_NODE_H */ 283