summaryrefslogtreecommitdiffstats
path: root/src/include/parser/parse_node.h
blob: cf9c75902588ad0561a962a5bc0d6c53ea76b518 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
/*-------------------------------------------------------------------------
 *
 * parse_node.h
 *		Internal definitions for parser
 *
 *
 * Portions Copyright (c) 1996-2022, 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 */
	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_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_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_joinexprs;	/* JoinExprs for RTE_JOIN p_rtable entries */
	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.
 *
 * 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).
 * 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 */
	/* 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 */