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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) 1996-2017, 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  EXPR_KIND_CALL /* CALL argument */
73 
74 
75 /*
76  * Function signatures for parser hooks
77  */
78 typedef struct ParseState ParseState;
79 
80 typedef Node *(*PreParseColumnRefHook) (ParseState *pstate, ColumnRef *cref);
81 typedef Node *(*PostParseColumnRefHook) (ParseState *pstate, ColumnRef *cref, Node *var);
82 typedef Node *(*ParseParamRefHook) (ParseState *pstate, ParamRef *pref);
83 typedef Node *(*CoerceParamHook) (ParseState *pstate, Param *param,
84  Oid targetTypeId, int32 targetTypeMod,
85  int location);
86 
87 
88 /*
89  * State information used during parse analysis
90  *
91  * parentParseState: NULL in a top-level ParseState. When parsing a subquery,
92  * links to current parse state of outer query.
93  *
94  * p_sourcetext: source string that generated the raw parsetree being
95  * analyzed, or NULL if not available. (The string is used only to
96  * generate cursor positions in error messages: we need it to convert
97  * byte-wise locations in parse structures to character-wise cursor
98  * positions.)
99  *
100  * p_rtable: list of RTEs that will become the rangetable of the query.
101  * Note that neither relname nor refname of these entries are necessarily
102  * unique; searching the rtable by name is a bad idea.
103  *
104  * p_joinexprs: list of JoinExpr nodes associated with p_rtable entries.
105  * This is one-for-one with p_rtable, but contains NULLs for non-join
106  * RTEs, and may be shorter than p_rtable if the last RTE(s) aren't joins.
107  *
108  * p_joinlist: list of join items (RangeTblRef and JoinExpr nodes) that
109  * will become the fromlist of the query's top-level FromExpr node.
110  *
111  * p_namespace: list of ParseNamespaceItems that represents the current
112  * namespace for table and column lookup. (The RTEs listed here may be just
113  * a subset of the whole rtable. See ParseNamespaceItem comments below.)
114  *
115  * p_lateral_active: true if we are currently parsing a LATERAL subexpression
116  * of this parse level. This makes p_lateral_only namespace items visible,
117  * whereas they are not visible when p_lateral_active is FALSE.
118  *
119  * p_ctenamespace: list of CommonTableExprs (WITH items) that are visible
120  * at the moment. This is entirely different from p_namespace because a CTE
121  * is not an RTE, rather "visibility" means you could make an RTE from it.
122  *
123  * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet
124  * visible due to scope rules. This is used to help improve error messages.
125  *
126  * p_parent_cte: CommonTableExpr that immediately contains the current query,
127  * if any.
128  *
129  * p_target_relation: target relation, if query is INSERT, UPDATE, or DELETE.
130  *
131  * p_target_rangetblentry: target relation's entry in the rtable list.
132  *
133  * p_is_insert: true to process assignment expressions like INSERT, false
134  * to process them like UPDATE. (Note this can change intra-statement, for
135  * cases like INSERT ON CONFLICT UPDATE.)
136  *
137  * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses.
138  * We collect these while transforming expressions and then transform them
139  * afterwards (so that any resjunk tlist items needed for the sort/group
140  * clauses end up at the end of the query tlist). A WindowDef's location in
141  * this list, counting from 1, is the winref number to use to reference it.
142  *
143  * p_expr_kind: kind of expression we're currently parsing, as per enum above;
144  * EXPR_KIND_NONE when not in an expression.
145  *
146  * p_next_resno: next TargetEntry.resno to assign, starting from 1.
147  *
148  * p_multiassign_exprs: partially-processed MultiAssignRef source expressions.
149  *
150  * p_locking_clause: query's FOR UPDATE/FOR SHARE clause, if any.
151  *
152  * p_locked_from_parent: true if parent query level applies FOR UPDATE/SHARE
153  * to this subquery as a whole.
154  *
155  * p_resolve_unknowns: resolve unknown-type SELECT output columns as type TEXT
156  * (this is true by default).
157  *
158  * p_hasAggs, p_hasWindowFuncs, etc: true if we've found any of the indicated
159  * constructs in the query.
160  *
161  * p_last_srf: the set-returning FuncExpr or OpExpr most recently found in
162  * the query, or NULL if none.
163  *
164  * p_pre_columnref_hook, etc: optional parser hook functions for modifying the
165  * interpretation of ColumnRefs and ParamRefs.
166  *
167  * p_ref_hook_state: passthrough state for the parser hook functions.
168  */
170 {
171  struct ParseState *parentParseState; /* stack link */
172  const char *p_sourcetext; /* source text, or NULL if not available */
173  List *p_rtable; /* range table so far */
174  List *p_joinexprs; /* JoinExprs for RTE_JOIN p_rtable entries */
175  List *p_joinlist; /* join items so far (will become FromExpr
176  * node's fromlist) */
177  List *p_namespace; /* currently-referenceable RTEs (List of
178  * ParseNamespaceItem) */
179  bool p_lateral_active; /* p_lateral_only items visible? */
180  List *p_ctenamespace; /* current namespace for common table exprs */
181  List *p_future_ctes; /* common table exprs not yet in namespace */
182  CommonTableExpr *p_parent_cte; /* this query's containing CTE */
183  Relation p_target_relation; /* INSERT/UPDATE/DELETE target rel */
184  RangeTblEntry *p_target_rangetblentry; /* target rel's RTE */
185  bool p_is_insert; /* process assignment like INSERT not UPDATE */
186  List *p_windowdefs; /* raw representations of window clauses */
187  ParseExprKind p_expr_kind; /* what kind of expression we're parsing */
188  int p_next_resno; /* next targetlist resno to assign */
189  List *p_multiassign_exprs; /* junk tlist entries for multiassign */
190  List *p_locking_clause; /* raw FOR UPDATE/FOR SHARE info */
191  bool p_locked_from_parent; /* parent has marked this subquery
192  * with FOR UPDATE/FOR SHARE */
193  bool p_resolve_unknowns; /* resolve unknown-type SELECT outputs as
194  * type text */
195 
196  QueryEnvironment *p_queryEnv; /* curr env, incl refs to enclosing env */
197 
198  /* Flags telling about things found in the query: */
199  bool p_hasAggs;
204 
205  Node *p_last_srf; /* most recent set-returning func/op found */
206 
207  /*
208  * Optional hook functions for parser callbacks. These are null unless
209  * set up by the caller of make_parsestate.
210  */
215  void *p_ref_hook_state; /* common passthrough link for above */
216 };
217 
218 /*
219  * An element of a namespace list.
220  *
221  * Namespace items with p_rel_visible set define which RTEs are accessible by
222  * qualified names, while those with p_cols_visible set define which RTEs are
223  * accessible by unqualified names. These sets are different because a JOIN
224  * without an alias does not hide the contained tables (so they must be
225  * visible for qualified references) but it does hide their columns
226  * (unqualified references to the columns refer to the JOIN, not the member
227  * tables, so we must not complain that such a reference is ambiguous).
228  * Various special RTEs such as NEW/OLD for rules may also appear with only
229  * one flag set.
230  *
231  * While processing the FROM clause, namespace items may appear with
232  * p_lateral_only set, meaning they are visible only to LATERAL
233  * subexpressions. (The pstate's p_lateral_active flag tells whether we are
234  * inside such a subexpression at the moment.) If p_lateral_ok is not set,
235  * it's an error to actually use such a namespace item. One might think it
236  * would be better to just exclude such items from visibility, but the wording
237  * of SQL:2008 requires us to do it this way. We also use p_lateral_ok to
238  * forbid LATERAL references to an UPDATE/DELETE target table.
239  *
240  * At no time should a namespace list contain two entries that conflict
241  * according to the rules in checkNameSpaceConflicts; but note that those
242  * are more complicated than "must have different alias names", so in practice
243  * code searching a namespace list has to check for ambiguous references.
244  */
245 typedef struct ParseNamespaceItem
246 {
247  RangeTblEntry *p_rte; /* The relation's rangetable entry */
248  bool p_rel_visible; /* Relation name is visible? */
249  bool p_cols_visible; /* Column names visible as unqualified refs? */
250  bool p_lateral_only; /* Is only visible to LATERAL expressions? */
251  bool p_lateral_ok; /* If so, does join type allow use? */
253 
254 /* Support for parser_errposition_callback function */
255 typedef struct ParseCallbackState
256 {
258  int location;
261 
262 
264 extern void free_parsestate(ParseState *pstate);
265 extern int parser_errposition(ParseState *pstate, int location);
266 
268  ParseState *pstate, int location);
270 
271 extern Var *make_var(ParseState *pstate, RangeTblEntry *rte, int attrno,
272  int location);
273 extern Oid transformArrayType(Oid *arrayType, int32 *arrayTypmod);
275  Node *arrayBase,
276  Oid arrayType,
277  Oid elementType,
278  int32 arrayTypMod,
279  List *indirection,
280  Node *assignFrom);
281 extern Const *make_const(ParseState *pstate, Value *value, int location);
282 
283 #endif /* PARSE_NODE_H */
bool p_hasSubLinks
Definition: parse_node.h:202
struct ParseNamespaceItem ParseNamespaceItem
QueryEnvironment * p_queryEnv
Definition: parse_node.h:196
Node *(* PreParseColumnRefHook)(ParseState *pstate, ColumnRef *cref)
Definition: parse_node.h:80
Node *(* PostParseColumnRefHook)(ParseState *pstate, ColumnRef *cref, Node *var)
Definition: parse_node.h:81
CoerceParamHook p_coerce_param_hook
Definition: parse_node.h:214
bool p_hasTargetSRFs
Definition: parse_node.h:201
Definition: nodes.h:512
List * p_multiassign_exprs
Definition: parse_node.h:189
bool p_hasAggs
Definition: parse_node.h:199
Oid transformArrayType(Oid *arrayType, int32 *arrayTypmod)
Definition: parse_node.c:216
ErrorContextCallback errcallback
Definition: parse_node.h:259
unsigned int Oid
Definition: postgres_ext.h:31
Definition: primnodes.h:163
CommonTableExpr * p_parent_cte
Definition: parse_node.h:182
ParseExprKind
Definition: parse_node.h:33
PostParseColumnRefHook p_post_columnref_hook
Definition: parse_node.h:212
signed int int32
Definition: c.h:284
bool p_hasWindowFuncs
Definition: parse_node.h:200
bool p_locked_from_parent
Definition: parse_node.h:191
RangeTblEntry * p_rte
Definition: parse_node.h:247
List * p_windowdefs
Definition: parse_node.h:186
bool p_resolve_unknowns
Definition: parse_node.h:193
static struct @121 value
List * p_namespace
Definition: parse_node.h:177
ParseParamRefHook p_paramref_hook
Definition: parse_node.h:213
Node *(* CoerceParamHook)(ParseState *pstate, Param *param, Oid targetTypeId, int32 targetTypeMod, int location)
Definition: parse_node.h:83
int p_next_resno
Definition: parse_node.h:188
List * p_locking_clause
Definition: parse_node.h:190
const char * p_sourcetext
Definition: parse_node.h:172
ArrayRef * transformArraySubscripts(ParseState *pstate, Node *arrayBase, Oid arrayType, Oid elementType, int32 arrayTypMod, List *indirection, Node *assignFrom)
Definition: parse_node.c:294
Node *(* ParseParamRefHook)(ParseState *pstate, ParamRef *pref)
Definition: parse_node.h:82
bool p_hasModifyingCTE
Definition: parse_node.h:203
ParseState * make_parsestate(ParseState *parentParseState)
Definition: parse_node.c:44
ParseState * pstate
Definition: parse_node.h:257
struct ParseState * parentParseState
Definition: parse_node.h:171
List * p_future_ctes
Definition: parse_node.h:181
Node * p_last_srf
Definition: parse_node.h:205
RangeTblEntry * p_target_rangetblentry
Definition: parse_node.h:184
ParseExprKind p_expr_kind
Definition: parse_node.h:187
bool p_lateral_active
Definition: parse_node.h:179
int parser_errposition(ParseState *pstate, int location)
Definition: parse_node.c:111
void * p_ref_hook_state
Definition: parse_node.h:215
Definition: value.h:42
void setup_parser_errposition_callback(ParseCallbackState *pcbstate, ParseState *pstate, int location)
Definition: parse_node.c:145
Var * make_var(ParseState *pstate, RangeTblEntry *rte, int attrno, int location)
Definition: parse_node.c:189
struct ParseCallbackState ParseCallbackState
Relation p_target_relation
Definition: parse_node.h:183
bool p_is_insert
Definition: parse_node.h:185
Const * make_const(ParseState *pstate, Value *value, int location)
Definition: parse_node.c:470
List * p_ctenamespace
Definition: parse_node.h:180
List * p_joinlist
Definition: parse_node.h:175
void free_parsestate(ParseState *pstate)
Definition: parse_node.c:77
PreParseColumnRefHook p_pre_columnref_hook
Definition: parse_node.h:211
Definition: pg_list.h:45
List * p_joinexprs
Definition: parse_node.h:174
void cancel_parser_errposition_callback(ParseCallbackState *pcbstate)
Definition: parse_node.c:161
List * p_rtable
Definition: parse_node.h:173