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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 */
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_pre_columnref_hook, etc: optional parser hook functions for modifying the
161  * interpretation of ColumnRefs and ParamRefs.
162  *
163  * p_ref_hook_state: passthrough state for the parser hook functions.
164  */
166 {
167  struct ParseState *parentParseState; /* stack link */
168  const char *p_sourcetext; /* source text, or NULL if not available */
169  List *p_rtable; /* range table so far */
170  List *p_joinexprs; /* JoinExprs for RTE_JOIN p_rtable entries */
171  List *p_joinlist; /* join items so far (will become FromExpr
172  * node's fromlist) */
173  List *p_namespace; /* currently-referenceable RTEs (List of
174  * ParseNamespaceItem) */
175  bool p_lateral_active; /* p_lateral_only items visible? */
176  List *p_ctenamespace; /* current namespace for common table exprs */
177  List *p_future_ctes; /* common table exprs not yet in namespace */
178  CommonTableExpr *p_parent_cte; /* this query's containing CTE */
179  Relation p_target_relation; /* INSERT/UPDATE/DELETE target rel */
180  RangeTblEntry *p_target_rangetblentry; /* target rel's RTE */
181  bool p_is_insert; /* process assignment like INSERT not UPDATE */
182  List *p_windowdefs; /* raw representations of window clauses */
183  ParseExprKind p_expr_kind; /* what kind of expression we're parsing */
184  int p_next_resno; /* next targetlist resno to assign */
185  List *p_multiassign_exprs; /* junk tlist entries for multiassign */
186  List *p_locking_clause; /* raw FOR UPDATE/FOR SHARE info */
187  bool p_locked_from_parent; /* parent has marked this subquery
188  * with FOR UPDATE/FOR SHARE */
189  bool p_resolve_unknowns; /* resolve unknown-type SELECT outputs
190  * as type text */
191 
192  QueryEnvironment *p_queryEnv; /* curr env, incl refs to enclosing env */
193 
194  /* Flags telling about things found in the query: */
195  bool p_hasAggs;
200 
201  /*
202  * Optional hook functions for parser callbacks. These are null unless
203  * set up by the caller of make_parsestate.
204  */
209  void *p_ref_hook_state; /* common passthrough link for above */
210 };
211 
212 /*
213  * An element of a namespace list.
214  *
215  * Namespace items with p_rel_visible set define which RTEs are accessible by
216  * qualified names, while those with p_cols_visible set define which RTEs are
217  * accessible by unqualified names. These sets are different because a JOIN
218  * without an alias does not hide the contained tables (so they must be
219  * visible for qualified references) but it does hide their columns
220  * (unqualified references to the columns refer to the JOIN, not the member
221  * tables, so we must not complain that such a reference is ambiguous).
222  * Various special RTEs such as NEW/OLD for rules may also appear with only
223  * one flag set.
224  *
225  * While processing the FROM clause, namespace items may appear with
226  * p_lateral_only set, meaning they are visible only to LATERAL
227  * subexpressions. (The pstate's p_lateral_active flag tells whether we are
228  * inside such a subexpression at the moment.) If p_lateral_ok is not set,
229  * it's an error to actually use such a namespace item. One might think it
230  * would be better to just exclude such items from visibility, but the wording
231  * of SQL:2008 requires us to do it this way. We also use p_lateral_ok to
232  * forbid LATERAL references to an UPDATE/DELETE target table.
233  *
234  * At no time should a namespace list contain two entries that conflict
235  * according to the rules in checkNameSpaceConflicts; but note that those
236  * are more complicated than "must have different alias names", so in practice
237  * code searching a namespace list has to check for ambiguous references.
238  */
239 typedef struct ParseNamespaceItem
240 {
241  RangeTblEntry *p_rte; /* The relation's rangetable entry */
242  bool p_rel_visible; /* Relation name is visible? */
243  bool p_cols_visible; /* Column names visible as unqualified refs? */
244  bool p_lateral_only; /* Is only visible to LATERAL expressions? */
245  bool p_lateral_ok; /* If so, does join type allow use? */
247 
248 /* Support for parser_errposition_callback function */
249 typedef struct ParseCallbackState
250 {
252  int location;
255 
256 
257 extern ParseState *make_parsestate(ParseState *parentParseState);
258 extern void free_parsestate(ParseState *pstate);
259 extern int parser_errposition(ParseState *pstate, int location);
260 
262  ParseState *pstate, int location);
264 
265 extern Var *make_var(ParseState *pstate, RangeTblEntry *rte, int attrno,
266  int location);
267 extern Oid transformArrayType(Oid *arrayType, int32 *arrayTypmod);
269  Node *arrayBase,
270  Oid arrayType,
271  Oid elementType,
272  int32 arrayTypMod,
273  List *indirection,
274  Node *assignFrom);
275 extern Const *make_const(ParseState *pstate, Value *value, int location);
276 
277 #endif /* PARSE_NODE_H */
bool p_hasSubLinks
Definition: parse_node.h:198
struct ParseNamespaceItem ParseNamespaceItem
QueryEnvironment * p_queryEnv
Definition: parse_node.h:192
CoerceParamHook p_coerce_param_hook
Definition: parse_node.h:208
bool p_hasTargetSRFs
Definition: parse_node.h:197
Definition: nodes.h:509
Node *(* PreParseColumnRefHook)(ParseState *pstate, ColumnRef *cref)
Definition: parse_node.h:79
List * p_multiassign_exprs
Definition: parse_node.h:185
bool p_hasAggs
Definition: parse_node.h:195
Oid transformArrayType(Oid *arrayType, int32 *arrayTypmod)
Definition: parse_node.c:216
ErrorContextCallback errcallback
Definition: parse_node.h:253
unsigned int Oid
Definition: postgres_ext.h:31
Definition: primnodes.h:163
CommonTableExpr * p_parent_cte
Definition: parse_node.h:178
ParseExprKind
Definition: parse_node.h:33
PostParseColumnRefHook p_post_columnref_hook
Definition: parse_node.h:206
signed int int32
Definition: c.h:256
bool p_hasWindowFuncs
Definition: parse_node.h:196
bool p_locked_from_parent
Definition: parse_node.h:187
RangeTblEntry * p_rte
Definition: parse_node.h:241
List * p_windowdefs
Definition: parse_node.h:182
bool p_resolve_unknowns
Definition: parse_node.h:189
List * p_namespace
Definition: parse_node.h:173
ParseParamRefHook p_paramref_hook
Definition: parse_node.h:207
int p_next_resno
Definition: parse_node.h:184
List * p_locking_clause
Definition: parse_node.h:186
const char * p_sourcetext
Definition: parse_node.h:168
ArrayRef * transformArraySubscripts(ParseState *pstate, Node *arrayBase, Oid arrayType, Oid elementType, int32 arrayTypMod, List *indirection, Node *assignFrom)
Definition: parse_node.c:294
bool p_hasModifyingCTE
Definition: parse_node.h:199
ParseState * make_parsestate(ParseState *parentParseState)
Definition: parse_node.c:44
ParseState * pstate
Definition: parse_node.h:251
struct ParseState * parentParseState
Definition: parse_node.h:167
List * p_future_ctes
Definition: parse_node.h:177
Node *(* CoerceParamHook)(ParseState *pstate, Param *param, Oid targetTypeId, int32 targetTypeMod, int location)
Definition: parse_node.h:82
RangeTblEntry * p_target_rangetblentry
Definition: parse_node.h:180
ParseExprKind p_expr_kind
Definition: parse_node.h:183
bool p_lateral_active
Definition: parse_node.h:175
int parser_errposition(ParseState *pstate, int location)
Definition: parse_node.c:111
void * p_ref_hook_state
Definition: parse_node.h:209
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:179
Node *(* PostParseColumnRefHook)(ParseState *pstate, ColumnRef *cref, Node *var)
Definition: parse_node.h:80
bool p_is_insert
Definition: parse_node.h:181
Const * make_const(ParseState *pstate, Value *value, int location)
Definition: parse_node.c:470
List * p_ctenamespace
Definition: parse_node.h:176
List * p_joinlist
Definition: parse_node.h:171
void free_parsestate(ParseState *pstate)
Definition: parse_node.c:77
PreParseColumnRefHook p_pre_columnref_hook
Definition: parse_node.h:205
static struct @121 value
Definition: pg_list.h:45
Node *(* ParseParamRefHook)(ParseState *pstate, ParamRef *pref)
Definition: parse_node.h:81
List * p_joinexprs
Definition: parse_node.h:170
void cancel_parser_errposition_callback(ParseCallbackState *pcbstate)
Definition: parse_node.c:161
List * p_rtable
Definition: parse_node.h:169