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parse_node.h
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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;
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 */
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  */
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;
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  */
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  */
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  */
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 {
303  int location;
306 
307 
309 extern void free_parsestate(ParseState *pstate);
310 extern int parser_errposition(ParseState *pstate, int location);
311 
313  ParseState *pstate, int location);
315 
316 extern Oid transformContainerType(Oid *containerType, int32 *containerTypmod);
317 
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 */
SubscriptingRef * transformContainerSubscripts(ParseState *pstate, Node *containerBase, Oid containerType, Oid elementType, int32 containerTypMod, List *indirection, Node *assignFrom)
Definition: parse_node.c:276
bool p_hasSubLinks
Definition: parse_node.h:209
QueryEnvironment * p_queryEnv
Definition: parse_node.h:203
Node *(* PreParseColumnRefHook)(ParseState *pstate, ColumnRef *cref)
Definition: parse_node.h:87
Node *(* PostParseColumnRefHook)(ParseState *pstate, ColumnRef *cref, Node *var)
Definition: parse_node.h:88
ParseState * parentParseState
Definition: parse_node.h:178
CoerceParamHook p_coerce_param_hook
Definition: parse_node.h:221
bool p_hasTargetSRFs
Definition: parse_node.h:208
static struct @145 value
Definition: nodes.h:525
List * p_multiassign_exprs
Definition: parse_node.h:196
bool p_hasAggs
Definition: parse_node.h:206
ParseNamespaceItem * p_target_nsitem
Definition: parse_node.h:191
ErrorContextCallback errcallback
Definition: parse_node.h:304
unsigned int Oid
Definition: postgres_ext.h:31
CommonTableExpr * p_parent_cte
Definition: parse_node.h:189
ParseExprKind
Definition: parse_node.h:38
PostParseColumnRefHook p_post_columnref_hook
Definition: parse_node.h:219
signed int int32
Definition: c.h:347
bool p_hasWindowFuncs
Definition: parse_node.h:207
bool p_locked_from_parent
Definition: parse_node.h:198
Oid transformContainerType(Oid *containerType, int32 *containerTypmod)
Definition: parse_node.c:195
RangeTblEntry * p_rte
Definition: parse_node.h:257
List * p_windowdefs
Definition: parse_node.h:193
bool p_resolve_unknowns
Definition: parse_node.h:200
AttrNumber p_varattno
Definition: parse_node.h:291
List * p_namespace
Definition: parse_node.h:184
ParseParamRefHook p_paramref_hook
Definition: parse_node.h:220
Node *(* CoerceParamHook)(ParseState *pstate, Param *param, Oid targetTypeId, int32 targetTypeMod, int location)
Definition: parse_node.h:90
int p_next_resno
Definition: parse_node.h:195
List * p_locking_clause
Definition: parse_node.h:197
const char * p_sourcetext
Definition: parse_node.h:179
Node *(* ParseParamRefHook)(ParseState *pstate, ParamRef *pref)
Definition: parse_node.h:89
bool p_hasModifyingCTE
Definition: parse_node.h:210
ParseState * make_parsestate(ParseState *parentParseState)
Definition: parse_node.c:43
ParseState * pstate
Definition: parse_node.h:302
List * p_future_ctes
Definition: parse_node.h:188
Node * p_last_srf
Definition: parse_node.h:212
unsigned int Index
Definition: c.h:476
ParseExprKind p_expr_kind
Definition: parse_node.h:194
bool p_lateral_active
Definition: parse_node.h:186
int parser_errposition(ParseState *pstate, int location)
Definition: parse_node.c:110
void * p_ref_hook_state
Definition: parse_node.h:222
Definition: value.h:42
void setup_parser_errposition_callback(ParseCallbackState *pcbstate, ParseState *pstate, int location)
Definition: parse_node.c:144
ParseNamespaceColumn * p_nscolumns
Definition: parse_node.h:260
struct ParseCallbackState ParseCallbackState
Relation p_target_relation
Definition: parse_node.h:190
bool p_is_insert
Definition: parse_node.h:192
AttrNumber p_varattnosyn
Definition: parse_node.h:296
Const * make_const(ParseState *pstate, Value *value, int location)
Definition: parse_node.c:455
List * p_ctenamespace
Definition: parse_node.h:187
List * p_joinlist
Definition: parse_node.h:182
void free_parsestate(ParseState *pstate)
Definition: parse_node.c:76
PreParseColumnRefHook p_pre_columnref_hook
Definition: parse_node.h:218
Definition: pg_list.h:50
int16 AttrNumber
Definition: attnum.h:21
List * p_joinexprs
Definition: parse_node.h:181
void cancel_parser_errposition_callback(ParseCallbackState *pcbstate)
Definition: parse_node.c:160
List * p_rtable
Definition: parse_node.h:180