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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:15:05 +0000
commit46651ce6fe013220ed397add242004d764fc0153 (patch)
tree6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/backend/parser/parse_target.c
parentInitial commit. (diff)
downloadpostgresql-14-upstream.tar.xz
postgresql-14-upstream.zip
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--src/backend/parser/parse_target.c1965
1 files changed, 1965 insertions, 0 deletions
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
new file mode 100644
index 0000000..9ce3a0d
--- /dev/null
+++ b/src/backend/parser/parse_target.c
@@ -0,0 +1,1965 @@
+/*-------------------------------------------------------------------------
+ *
+ * parse_target.c
+ * handle target lists
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/parser/parse_target.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "catalog/pg_type.h"
+#include "commands/dbcommands.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "nodes/makefuncs.h"
+#include "nodes/nodeFuncs.h"
+#include "parser/parse_coerce.h"
+#include "parser/parse_expr.h"
+#include "parser/parse_func.h"
+#include "parser/parse_relation.h"
+#include "parser/parse_target.h"
+#include "parser/parse_type.h"
+#include "parser/parsetree.h"
+#include "utils/builtins.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include "utils/typcache.h"
+
+static void markTargetListOrigin(ParseState *pstate, TargetEntry *tle,
+ Var *var, int levelsup);
+static Node *transformAssignmentSubscripts(ParseState *pstate,
+ Node *basenode,
+ const char *targetName,
+ Oid targetTypeId,
+ int32 targetTypMod,
+ Oid targetCollation,
+ List *subscripts,
+ bool isSlice,
+ List *indirection,
+ ListCell *next_indirection,
+ Node *rhs,
+ CoercionContext ccontext,
+ int location);
+static List *ExpandColumnRefStar(ParseState *pstate, ColumnRef *cref,
+ bool make_target_entry);
+static List *ExpandAllTables(ParseState *pstate, int location);
+static List *ExpandIndirectionStar(ParseState *pstate, A_Indirection *ind,
+ bool make_target_entry, ParseExprKind exprKind);
+static List *ExpandSingleTable(ParseState *pstate, ParseNamespaceItem *nsitem,
+ int sublevels_up, int location,
+ bool make_target_entry);
+static List *ExpandRowReference(ParseState *pstate, Node *expr,
+ bool make_target_entry);
+static int FigureColnameInternal(Node *node, char **name);
+
+
+/*
+ * transformTargetEntry()
+ * Transform any ordinary "expression-type" node into a targetlist entry.
+ * This is exported so that parse_clause.c can generate targetlist entries
+ * for ORDER/GROUP BY items that are not already in the targetlist.
+ *
+ * node the (untransformed) parse tree for the value expression.
+ * expr the transformed expression, or NULL if caller didn't do it yet.
+ * exprKind expression kind (EXPR_KIND_SELECT_TARGET, etc)
+ * colname the column name to be assigned, or NULL if none yet set.
+ * resjunk true if the target should be marked resjunk, ie, it is not
+ * wanted in the final projected tuple.
+ */
+TargetEntry *
+transformTargetEntry(ParseState *pstate,
+ Node *node,
+ Node *expr,
+ ParseExprKind exprKind,
+ char *colname,
+ bool resjunk)
+{
+ /* Transform the node if caller didn't do it already */
+ if (expr == NULL)
+ {
+ /*
+ * If it's a SetToDefault node and we should allow that, pass it
+ * through unmodified. (transformExpr will throw the appropriate
+ * error if we're disallowing it.)
+ */
+ if (exprKind == EXPR_KIND_UPDATE_SOURCE && IsA(node, SetToDefault))
+ expr = node;
+ else
+ expr = transformExpr(pstate, node, exprKind);
+ }
+
+ if (colname == NULL && !resjunk)
+ {
+ /*
+ * Generate a suitable column name for a column without any explicit
+ * 'AS ColumnName' clause.
+ */
+ colname = FigureColname(node);
+ }
+
+ return makeTargetEntry((Expr *) expr,
+ (AttrNumber) pstate->p_next_resno++,
+ colname,
+ resjunk);
+}
+
+
+/*
+ * transformTargetList()
+ * Turns a list of ResTarget's into a list of TargetEntry's.
+ *
+ * This code acts mostly the same for SELECT, UPDATE, or RETURNING lists;
+ * the main thing is to transform the given expressions (the "val" fields).
+ * The exprKind parameter distinguishes these cases when necessary.
+ */
+List *
+transformTargetList(ParseState *pstate, List *targetlist,
+ ParseExprKind exprKind)
+{
+ List *p_target = NIL;
+ bool expand_star;
+ ListCell *o_target;
+
+ /* Shouldn't have any leftover multiassign items at start */
+ Assert(pstate->p_multiassign_exprs == NIL);
+
+ /* Expand "something.*" in SELECT and RETURNING, but not UPDATE */
+ expand_star = (exprKind != EXPR_KIND_UPDATE_SOURCE);
+
+ foreach(o_target, targetlist)
+ {
+ ResTarget *res = (ResTarget *) lfirst(o_target);
+
+ /*
+ * Check for "something.*". Depending on the complexity of the
+ * "something", the star could appear as the last field in ColumnRef,
+ * or as the last indirection item in A_Indirection.
+ */
+ if (expand_star)
+ {
+ if (IsA(res->val, ColumnRef))
+ {
+ ColumnRef *cref = (ColumnRef *) res->val;
+
+ if (IsA(llast(cref->fields), A_Star))
+ {
+ /* It is something.*, expand into multiple items */
+ p_target = list_concat(p_target,
+ ExpandColumnRefStar(pstate,
+ cref,
+ true));
+ continue;
+ }
+ }
+ else if (IsA(res->val, A_Indirection))
+ {
+ A_Indirection *ind = (A_Indirection *) res->val;
+
+ if (IsA(llast(ind->indirection), A_Star))
+ {
+ /* It is something.*, expand into multiple items */
+ p_target = list_concat(p_target,
+ ExpandIndirectionStar(pstate,
+ ind,
+ true,
+ exprKind));
+ continue;
+ }
+ }
+ }
+
+ /*
+ * Not "something.*", or we want to treat that as a plain whole-row
+ * variable, so transform as a single expression
+ */
+ p_target = lappend(p_target,
+ transformTargetEntry(pstate,
+ res->val,
+ NULL,
+ exprKind,
+ res->name,
+ false));
+ }
+
+ /*
+ * If any multiassign resjunk items were created, attach them to the end
+ * of the targetlist. This should only happen in an UPDATE tlist. We
+ * don't need to worry about numbering of these items; transformUpdateStmt
+ * will set their resnos.
+ */
+ if (pstate->p_multiassign_exprs)
+ {
+ Assert(exprKind == EXPR_KIND_UPDATE_SOURCE);
+ p_target = list_concat(p_target, pstate->p_multiassign_exprs);
+ pstate->p_multiassign_exprs = NIL;
+ }
+
+ return p_target;
+}
+
+
+/*
+ * transformExpressionList()
+ *
+ * This is the identical transformation to transformTargetList, except that
+ * the input list elements are bare expressions without ResTarget decoration,
+ * and the output elements are likewise just expressions without TargetEntry
+ * decoration. Also, we don't expect any multiassign constructs within the
+ * list, so there's nothing to do for that. We use this for ROW() and
+ * VALUES() constructs.
+ *
+ * exprKind is not enough to tell us whether to allow SetToDefault, so
+ * an additional flag is needed for that.
+ */
+List *
+transformExpressionList(ParseState *pstate, List *exprlist,
+ ParseExprKind exprKind, bool allowDefault)
+{
+ List *result = NIL;
+ ListCell *lc;
+
+ foreach(lc, exprlist)
+ {
+ Node *e = (Node *) lfirst(lc);
+
+ /*
+ * Check for "something.*". Depending on the complexity of the
+ * "something", the star could appear as the last field in ColumnRef,
+ * or as the last indirection item in A_Indirection.
+ */
+ if (IsA(e, ColumnRef))
+ {
+ ColumnRef *cref = (ColumnRef *) e;
+
+ if (IsA(llast(cref->fields), A_Star))
+ {
+ /* It is something.*, expand into multiple items */
+ result = list_concat(result,
+ ExpandColumnRefStar(pstate, cref,
+ false));
+ continue;
+ }
+ }
+ else if (IsA(e, A_Indirection))
+ {
+ A_Indirection *ind = (A_Indirection *) e;
+
+ if (IsA(llast(ind->indirection), A_Star))
+ {
+ /* It is something.*, expand into multiple items */
+ result = list_concat(result,
+ ExpandIndirectionStar(pstate, ind,
+ false, exprKind));
+ continue;
+ }
+ }
+
+ /*
+ * Not "something.*", so transform as a single expression. If it's a
+ * SetToDefault node and we should allow that, pass it through
+ * unmodified. (transformExpr will throw the appropriate error if
+ * we're disallowing it.)
+ */
+ if (allowDefault && IsA(e, SetToDefault))
+ /* do nothing */ ;
+ else
+ e = transformExpr(pstate, e, exprKind);
+
+ result = lappend(result, e);
+ }
+
+ return result;
+}
+
+
+/*
+ * resolveTargetListUnknowns()
+ * Convert any unknown-type targetlist entries to type TEXT.
+ *
+ * We do this after we've exhausted all other ways of identifying the output
+ * column types of a query.
+ */
+void
+resolveTargetListUnknowns(ParseState *pstate, List *targetlist)
+{
+ ListCell *l;
+
+ foreach(l, targetlist)
+ {
+ TargetEntry *tle = (TargetEntry *) lfirst(l);
+ Oid restype = exprType((Node *) tle->expr);
+
+ if (restype == UNKNOWNOID)
+ {
+ tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
+ restype, TEXTOID, -1,
+ COERCION_IMPLICIT,
+ COERCE_IMPLICIT_CAST,
+ -1);
+ }
+ }
+}
+
+
+/*
+ * markTargetListOrigins()
+ * Mark targetlist columns that are simple Vars with the source
+ * table's OID and column number.
+ *
+ * Currently, this is done only for SELECT targetlists and RETURNING lists,
+ * since we only need the info if we are going to send it to the frontend.
+ */
+void
+markTargetListOrigins(ParseState *pstate, List *targetlist)
+{
+ ListCell *l;
+
+ foreach(l, targetlist)
+ {
+ TargetEntry *tle = (TargetEntry *) lfirst(l);
+
+ markTargetListOrigin(pstate, tle, (Var *) tle->expr, 0);
+ }
+}
+
+/*
+ * markTargetListOrigin()
+ * If 'var' is a Var of a plain relation, mark 'tle' with its origin
+ *
+ * levelsup is an extra offset to interpret the Var's varlevelsup correctly.
+ *
+ * Note that we do not drill down into views, but report the view as the
+ * column owner. There's also no need to drill down into joins: if we see
+ * a join alias Var, it must be a merged JOIN USING column (or possibly a
+ * whole-row Var); that is not a direct reference to any plain table column,
+ * so we don't report it.
+ */
+static void
+markTargetListOrigin(ParseState *pstate, TargetEntry *tle,
+ Var *var, int levelsup)
+{
+ int netlevelsup;
+ RangeTblEntry *rte;
+ AttrNumber attnum;
+
+ if (var == NULL || !IsA(var, Var))
+ return;
+ netlevelsup = var->varlevelsup + levelsup;
+ rte = GetRTEByRangeTablePosn(pstate, var->varno, netlevelsup);
+ attnum = var->varattno;
+
+ switch (rte->rtekind)
+ {
+ case RTE_RELATION:
+ /* It's a table or view, report it */
+ tle->resorigtbl = rte->relid;
+ tle->resorigcol = attnum;
+ break;
+ case RTE_SUBQUERY:
+ /* Subselect-in-FROM: copy up from the subselect */
+ if (attnum != InvalidAttrNumber)
+ {
+ TargetEntry *ste = get_tle_by_resno(rte->subquery->targetList,
+ attnum);
+
+ if (ste == NULL || ste->resjunk)
+ elog(ERROR, "subquery %s does not have attribute %d",
+ rte->eref->aliasname, attnum);
+ tle->resorigtbl = ste->resorigtbl;
+ tle->resorigcol = ste->resorigcol;
+ }
+ break;
+ case RTE_JOIN:
+ case RTE_FUNCTION:
+ case RTE_VALUES:
+ case RTE_TABLEFUNC:
+ case RTE_NAMEDTUPLESTORE:
+ case RTE_RESULT:
+ /* not a simple relation, leave it unmarked */
+ break;
+ case RTE_CTE:
+
+ /*
+ * CTE reference: copy up from the subquery, if possible. If the
+ * RTE is a recursive self-reference then we can't do anything
+ * because we haven't finished analyzing it yet. However, it's no
+ * big loss because we must be down inside the recursive term of a
+ * recursive CTE, and so any markings on the current targetlist
+ * are not going to affect the results anyway.
+ */
+ if (attnum != InvalidAttrNumber && !rte->self_reference)
+ {
+ CommonTableExpr *cte = GetCTEForRTE(pstate, rte, netlevelsup);
+ TargetEntry *ste;
+ List *tl = GetCTETargetList(cte);
+ int extra_cols = 0;
+
+ /*
+ * RTE for CTE will already have the search and cycle columns
+ * added, but the subquery won't, so skip looking those up.
+ */
+ if (cte->search_clause)
+ extra_cols += 1;
+ if (cte->cycle_clause)
+ extra_cols += 2;
+ if (extra_cols &&
+ attnum > list_length(tl) &&
+ attnum <= list_length(tl) + extra_cols)
+ break;
+
+ ste = get_tle_by_resno(tl, attnum);
+ if (ste == NULL || ste->resjunk)
+ elog(ERROR, "CTE %s does not have attribute %d",
+ rte->eref->aliasname, attnum);
+ tle->resorigtbl = ste->resorigtbl;
+ tle->resorigcol = ste->resorigcol;
+ }
+ break;
+ }
+}
+
+
+/*
+ * transformAssignedExpr()
+ * This is used in INSERT and UPDATE statements only. It prepares an
+ * expression for assignment to a column of the target table.
+ * This includes coercing the given value to the target column's type
+ * (if necessary), and dealing with any subfield names or subscripts
+ * attached to the target column itself. The input expression has
+ * already been through transformExpr().
+ *
+ * pstate parse state
+ * expr expression to be modified
+ * exprKind indicates which type of statement we're dealing with
+ * colname target column name (ie, name of attribute to be assigned to)
+ * attrno target attribute number
+ * indirection subscripts/field names for target column, if any
+ * location error cursor position for the target column, or -1
+ *
+ * Returns the modified expression.
+ *
+ * Note: location points at the target column name (SET target or INSERT
+ * column name list entry), and must therefore be -1 in an INSERT that
+ * omits the column name list. So we should usually prefer to use
+ * exprLocation(expr) for errors that can happen in a default INSERT.
+ */
+Expr *
+transformAssignedExpr(ParseState *pstate,
+ Expr *expr,
+ ParseExprKind exprKind,
+ const char *colname,
+ int attrno,
+ List *indirection,
+ int location)
+{
+ Relation rd = pstate->p_target_relation;
+ Oid type_id; /* type of value provided */
+ Oid attrtype; /* type of target column */
+ int32 attrtypmod;
+ Oid attrcollation; /* collation of target column */
+ ParseExprKind sv_expr_kind;
+
+ /*
+ * Save and restore identity of expression type we're parsing. We must
+ * set p_expr_kind here because we can parse subscripts without going
+ * through transformExpr().
+ */
+ Assert(exprKind != EXPR_KIND_NONE);
+ sv_expr_kind = pstate->p_expr_kind;
+ pstate->p_expr_kind = exprKind;
+
+ Assert(rd != NULL);
+ if (attrno <= 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot assign to system column \"%s\"",
+ colname),
+ parser_errposition(pstate, location)));
+ attrtype = attnumTypeId(rd, attrno);
+ attrtypmod = TupleDescAttr(rd->rd_att, attrno - 1)->atttypmod;
+ attrcollation = TupleDescAttr(rd->rd_att, attrno - 1)->attcollation;
+
+ /*
+ * If the expression is a DEFAULT placeholder, insert the attribute's
+ * type/typmod/collation into it so that exprType etc will report the
+ * right things. (We expect that the eventually substituted default
+ * expression will in fact have this type and typmod. The collation
+ * likely doesn't matter, but let's set it correctly anyway.) Also,
+ * reject trying to update a subfield or array element with DEFAULT, since
+ * there can't be any default for portions of a column.
+ */
+ if (expr && IsA(expr, SetToDefault))
+ {
+ SetToDefault *def = (SetToDefault *) expr;
+
+ def->typeId = attrtype;
+ def->typeMod = attrtypmod;
+ def->collation = attrcollation;
+ if (indirection)
+ {
+ if (IsA(linitial(indirection), A_Indices))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot set an array element to DEFAULT"),
+ parser_errposition(pstate, location)));
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot set a subfield to DEFAULT"),
+ parser_errposition(pstate, location)));
+ }
+ }
+
+ /* Now we can use exprType() safely. */
+ type_id = exprType((Node *) expr);
+
+ /*
+ * If there is indirection on the target column, prepare an array or
+ * subfield assignment expression. This will generate a new column value
+ * that the source value has been inserted into, which can then be placed
+ * in the new tuple constructed by INSERT or UPDATE.
+ */
+ if (indirection)
+ {
+ Node *colVar;
+
+ if (pstate->p_is_insert)
+ {
+ /*
+ * The command is INSERT INTO table (col.something) ... so there
+ * is not really a source value to work with. Insert a NULL
+ * constant as the source value.
+ */
+ colVar = (Node *) makeNullConst(attrtype, attrtypmod,
+ attrcollation);
+ }
+ else
+ {
+ /*
+ * Build a Var for the column to be updated.
+ */
+ Var *var;
+
+ var = makeVar(pstate->p_target_nsitem->p_rtindex, attrno,
+ attrtype, attrtypmod, attrcollation, 0);
+ var->location = location;
+
+ colVar = (Node *) var;
+ }
+
+ expr = (Expr *)
+ transformAssignmentIndirection(pstate,
+ colVar,
+ colname,
+ false,
+ attrtype,
+ attrtypmod,
+ attrcollation,
+ indirection,
+ list_head(indirection),
+ (Node *) expr,
+ COERCION_ASSIGNMENT,
+ location);
+ }
+ else
+ {
+ /*
+ * For normal non-qualified target column, do type checking and
+ * coercion.
+ */
+ Node *orig_expr = (Node *) expr;
+
+ expr = (Expr *)
+ coerce_to_target_type(pstate,
+ orig_expr, type_id,
+ attrtype, attrtypmod,
+ COERCION_ASSIGNMENT,
+ COERCE_IMPLICIT_CAST,
+ -1);
+ if (expr == NULL)
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("column \"%s\" is of type %s"
+ " but expression is of type %s",
+ colname,
+ format_type_be(attrtype),
+ format_type_be(type_id)),
+ errhint("You will need to rewrite or cast the expression."),
+ parser_errposition(pstate, exprLocation(orig_expr))));
+ }
+
+ pstate->p_expr_kind = sv_expr_kind;
+
+ return expr;
+}
+
+
+/*
+ * updateTargetListEntry()
+ * This is used in UPDATE statements (and ON CONFLICT DO UPDATE)
+ * only. It prepares an UPDATE TargetEntry for assignment to a
+ * column of the target table. This includes coercing the given
+ * value to the target column's type (if necessary), and dealing with
+ * any subfield names or subscripts attached to the target column
+ * itself.
+ *
+ * pstate parse state
+ * tle target list entry to be modified
+ * colname target column name (ie, name of attribute to be assigned to)
+ * attrno target attribute number
+ * indirection subscripts/field names for target column, if any
+ * location error cursor position (should point at column name), or -1
+ */
+void
+updateTargetListEntry(ParseState *pstate,
+ TargetEntry *tle,
+ char *colname,
+ int attrno,
+ List *indirection,
+ int location)
+{
+ /* Fix up expression as needed */
+ tle->expr = transformAssignedExpr(pstate,
+ tle->expr,
+ EXPR_KIND_UPDATE_TARGET,
+ colname,
+ attrno,
+ indirection,
+ location);
+
+ /*
+ * Set the resno to identify the target column --- the rewriter and
+ * planner depend on this. We also set the resname to identify the target
+ * column, but this is only for debugging purposes; it should not be
+ * relied on. (In particular, it might be out of date in a stored rule.)
+ */
+ tle->resno = (AttrNumber) attrno;
+ tle->resname = colname;
+}
+
+
+/*
+ * Process indirection (field selection or subscripting) of the target
+ * column in INSERT/UPDATE/assignment. This routine recurses for multiple
+ * levels of indirection --- but note that several adjacent A_Indices nodes
+ * in the indirection list are treated as a single multidimensional subscript
+ * operation.
+ *
+ * In the initial call, basenode is a Var for the target column in UPDATE,
+ * or a null Const of the target's type in INSERT, or a Param for the target
+ * variable in PL/pgSQL assignment. In recursive calls, basenode is NULL,
+ * indicating that a substitute node should be consed up if needed.
+ *
+ * targetName is the name of the field or subfield we're assigning to, and
+ * targetIsSubscripting is true if we're subscripting it. These are just for
+ * error reporting.
+ *
+ * targetTypeId, targetTypMod, targetCollation indicate the datatype and
+ * collation of the object to be assigned to (initially the target column,
+ * later some subobject).
+ *
+ * indirection is the list of indirection nodes, and indirection_cell is the
+ * start of the sublist remaining to process. When it's NULL, we're done
+ * recursing and can just coerce and return the RHS.
+ *
+ * rhs is the already-transformed value to be assigned; note it has not been
+ * coerced to any particular type.
+ *
+ * ccontext is the coercion level to use while coercing the rhs. For
+ * normal statements it'll be COERCION_ASSIGNMENT, but PL/pgSQL uses
+ * a special value.
+ *
+ * location is the cursor error position for any errors. (Note: this points
+ * to the head of the target clause, eg "foo" in "foo.bar[baz]". Later we
+ * might want to decorate indirection cells with their own location info,
+ * in which case the location argument could probably be dropped.)
+ */
+Node *
+transformAssignmentIndirection(ParseState *pstate,
+ Node *basenode,
+ const char *targetName,
+ bool targetIsSubscripting,
+ Oid targetTypeId,
+ int32 targetTypMod,
+ Oid targetCollation,
+ List *indirection,
+ ListCell *indirection_cell,
+ Node *rhs,
+ CoercionContext ccontext,
+ int location)
+{
+ Node *result;
+ List *subscripts = NIL;
+ bool isSlice = false;
+ ListCell *i;
+
+ if (indirection_cell && !basenode)
+ {
+ /*
+ * Set up a substitution. We abuse CaseTestExpr for this. It's safe
+ * to do so because the only nodes that will be above the CaseTestExpr
+ * in the finished expression will be FieldStore and SubscriptingRef
+ * nodes. (There could be other stuff in the tree, but it will be
+ * within other child fields of those node types.)
+ */
+ CaseTestExpr *ctest = makeNode(CaseTestExpr);
+
+ ctest->typeId = targetTypeId;
+ ctest->typeMod = targetTypMod;
+ ctest->collation = targetCollation;
+ basenode = (Node *) ctest;
+ }
+
+ /*
+ * We have to split any field-selection operations apart from
+ * subscripting. Adjacent A_Indices nodes have to be treated as a single
+ * multidimensional subscript operation.
+ */
+ for_each_cell(i, indirection, indirection_cell)
+ {
+ Node *n = lfirst(i);
+
+ if (IsA(n, A_Indices))
+ {
+ subscripts = lappend(subscripts, n);
+ if (((A_Indices *) n)->is_slice)
+ isSlice = true;
+ }
+ else if (IsA(n, A_Star))
+ {
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("row expansion via \"*\" is not supported here"),
+ parser_errposition(pstate, location)));
+ }
+ else
+ {
+ FieldStore *fstore;
+ Oid baseTypeId;
+ int32 baseTypeMod;
+ Oid typrelid;
+ AttrNumber attnum;
+ Oid fieldTypeId;
+ int32 fieldTypMod;
+ Oid fieldCollation;
+
+ Assert(IsA(n, String));
+
+ /* process subscripts before this field selection */
+ if (subscripts)
+ {
+ /* recurse, and then return because we're done */
+ return transformAssignmentSubscripts(pstate,
+ basenode,
+ targetName,
+ targetTypeId,
+ targetTypMod,
+ targetCollation,
+ subscripts,
+ isSlice,
+ indirection,
+ i,
+ rhs,
+ ccontext,
+ location);
+ }
+
+ /* No subscripts, so can process field selection here */
+
+ /*
+ * Look up the composite type, accounting for possibility that
+ * what we are given is a domain over composite.
+ */
+ baseTypeMod = targetTypMod;
+ baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
+
+ typrelid = typeidTypeRelid(baseTypeId);
+ if (!typrelid)
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("cannot assign to field \"%s\" of column \"%s\" because its type %s is not a composite type",
+ strVal(n), targetName,
+ format_type_be(targetTypeId)),
+ parser_errposition(pstate, location)));
+
+ attnum = get_attnum(typrelid, strVal(n));
+ if (attnum == InvalidAttrNumber)
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("cannot assign to field \"%s\" of column \"%s\" because there is no such column in data type %s",
+ strVal(n), targetName,
+ format_type_be(targetTypeId)),
+ parser_errposition(pstate, location)));
+ if (attnum < 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("cannot assign to system column \"%s\"",
+ strVal(n)),
+ parser_errposition(pstate, location)));
+
+ get_atttypetypmodcoll(typrelid, attnum,
+ &fieldTypeId, &fieldTypMod, &fieldCollation);
+
+ /* recurse to create appropriate RHS for field assign */
+ rhs = transformAssignmentIndirection(pstate,
+ NULL,
+ strVal(n),
+ false,
+ fieldTypeId,
+ fieldTypMod,
+ fieldCollation,
+ indirection,
+ lnext(indirection, i),
+ rhs,
+ ccontext,
+ location);
+
+ /* and build a FieldStore node */
+ fstore = makeNode(FieldStore);
+ fstore->arg = (Expr *) basenode;
+ fstore->newvals = list_make1(rhs);
+ fstore->fieldnums = list_make1_int(attnum);
+ fstore->resulttype = baseTypeId;
+
+ /* If target is a domain, apply constraints */
+ if (baseTypeId != targetTypeId)
+ return coerce_to_domain((Node *) fstore,
+ baseTypeId, baseTypeMod,
+ targetTypeId,
+ COERCION_IMPLICIT,
+ COERCE_IMPLICIT_CAST,
+ location,
+ false);
+
+ return (Node *) fstore;
+ }
+ }
+
+ /* process trailing subscripts, if any */
+ if (subscripts)
+ {
+ /* recurse, and then return because we're done */
+ return transformAssignmentSubscripts(pstate,
+ basenode,
+ targetName,
+ targetTypeId,
+ targetTypMod,
+ targetCollation,
+ subscripts,
+ isSlice,
+ indirection,
+ NULL,
+ rhs,
+ ccontext,
+ location);
+ }
+
+ /* base case: just coerce RHS to match target type ID */
+
+ result = coerce_to_target_type(pstate,
+ rhs, exprType(rhs),
+ targetTypeId, targetTypMod,
+ ccontext,
+ COERCE_IMPLICIT_CAST,
+ -1);
+ if (result == NULL)
+ {
+ if (targetIsSubscripting)
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("subscripted assignment to \"%s\" requires type %s"
+ " but expression is of type %s",
+ targetName,
+ format_type_be(targetTypeId),
+ format_type_be(exprType(rhs))),
+ errhint("You will need to rewrite or cast the expression."),
+ parser_errposition(pstate, location)));
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("subfield \"%s\" is of type %s"
+ " but expression is of type %s",
+ targetName,
+ format_type_be(targetTypeId),
+ format_type_be(exprType(rhs))),
+ errhint("You will need to rewrite or cast the expression."),
+ parser_errposition(pstate, location)));
+ }
+
+ return result;
+}
+
+/*
+ * helper for transformAssignmentIndirection: process container assignment
+ */
+static Node *
+transformAssignmentSubscripts(ParseState *pstate,
+ Node *basenode,
+ const char *targetName,
+ Oid targetTypeId,
+ int32 targetTypMod,
+ Oid targetCollation,
+ List *subscripts,
+ bool isSlice,
+ List *indirection,
+ ListCell *next_indirection,
+ Node *rhs,
+ CoercionContext ccontext,
+ int location)
+{
+ Node *result;
+ SubscriptingRef *sbsref;
+ Oid containerType;
+ int32 containerTypMod;
+ Oid typeNeeded;
+ int32 typmodNeeded;
+ Oid collationNeeded;
+
+ Assert(subscripts != NIL);
+
+ /* Identify the actual container type involved */
+ containerType = targetTypeId;
+ containerTypMod = targetTypMod;
+ transformContainerType(&containerType, &containerTypMod);
+
+ /* Process subscripts and identify required type for RHS */
+ sbsref = transformContainerSubscripts(pstate,
+ basenode,
+ containerType,
+ containerTypMod,
+ subscripts,
+ true);
+
+ typeNeeded = sbsref->refrestype;
+ typmodNeeded = sbsref->reftypmod;
+
+ /*
+ * Container normally has same collation as its elements, but there's an
+ * exception: we might be subscripting a domain over a container type. In
+ * that case use collation of the base type. (This is shaky for arbitrary
+ * subscripting semantics, but it doesn't matter all that much since we
+ * only use this to label the collation of a possible CaseTestExpr.)
+ */
+ if (containerType == targetTypeId)
+ collationNeeded = targetCollation;
+ else
+ collationNeeded = get_typcollation(containerType);
+
+ /* recurse to create appropriate RHS for container assign */
+ rhs = transformAssignmentIndirection(pstate,
+ NULL,
+ targetName,
+ true,
+ typeNeeded,
+ typmodNeeded,
+ collationNeeded,
+ indirection,
+ next_indirection,
+ rhs,
+ ccontext,
+ location);
+
+ /*
+ * Insert the already-properly-coerced RHS into the SubscriptingRef. Then
+ * set refrestype and reftypmod back to the container type's values.
+ */
+ sbsref->refassgnexpr = (Expr *) rhs;
+ sbsref->refrestype = containerType;
+ sbsref->reftypmod = containerTypMod;
+
+ result = (Node *) sbsref;
+
+ /* If target was a domain over container, need to coerce up to the domain */
+ if (containerType != targetTypeId)
+ {
+ Oid resulttype = exprType(result);
+
+ result = coerce_to_target_type(pstate,
+ result, resulttype,
+ targetTypeId, targetTypMod,
+ ccontext,
+ COERCE_IMPLICIT_CAST,
+ -1);
+ /* can fail if we had int2vector/oidvector, but not for true domains */
+ if (result == NULL)
+ ereport(ERROR,
+ (errcode(ERRCODE_CANNOT_COERCE),
+ errmsg("cannot cast type %s to %s",
+ format_type_be(resulttype),
+ format_type_be(targetTypeId)),
+ parser_errposition(pstate, location)));
+ }
+
+ return result;
+}
+
+
+/*
+ * checkInsertTargets -
+ * generate a list of INSERT column targets if not supplied, or
+ * test supplied column names to make sure they are in target table.
+ * Also return an integer list of the columns' attribute numbers.
+ */
+List *
+checkInsertTargets(ParseState *pstate, List *cols, List **attrnos)
+{
+ *attrnos = NIL;
+
+ if (cols == NIL)
+ {
+ /*
+ * Generate default column list for INSERT.
+ */
+ int numcol = RelationGetNumberOfAttributes(pstate->p_target_relation);
+
+ int i;
+
+ for (i = 0; i < numcol; i++)
+ {
+ ResTarget *col;
+ Form_pg_attribute attr;
+
+ attr = TupleDescAttr(pstate->p_target_relation->rd_att, i);
+
+ if (attr->attisdropped)
+ continue;
+
+ col = makeNode(ResTarget);
+ col->name = pstrdup(NameStr(attr->attname));
+ col->indirection = NIL;
+ col->val = NULL;
+ col->location = -1;
+ cols = lappend(cols, col);
+ *attrnos = lappend_int(*attrnos, i + 1);
+ }
+ }
+ else
+ {
+ /*
+ * Do initial validation of user-supplied INSERT column list.
+ */
+ Bitmapset *wholecols = NULL;
+ Bitmapset *partialcols = NULL;
+ ListCell *tl;
+
+ foreach(tl, cols)
+ {
+ ResTarget *col = (ResTarget *) lfirst(tl);
+ char *name = col->name;
+ int attrno;
+
+ /* Lookup column name, ereport on failure */
+ attrno = attnameAttNum(pstate->p_target_relation, name, false);
+ if (attrno == InvalidAttrNumber)
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column \"%s\" of relation \"%s\" does not exist",
+ name,
+ RelationGetRelationName(pstate->p_target_relation)),
+ parser_errposition(pstate, col->location)));
+
+ /*
+ * Check for duplicates, but only of whole columns --- we allow
+ * INSERT INTO foo (col.subcol1, col.subcol2)
+ */
+ if (col->indirection == NIL)
+ {
+ /* whole column; must not have any other assignment */
+ if (bms_is_member(attrno, wholecols) ||
+ bms_is_member(attrno, partialcols))
+ ereport(ERROR,
+ (errcode(ERRCODE_DUPLICATE_COLUMN),
+ errmsg("column \"%s\" specified more than once",
+ name),
+ parser_errposition(pstate, col->location)));
+ wholecols = bms_add_member(wholecols, attrno);
+ }
+ else
+ {
+ /* partial column; must not have any whole assignment */
+ if (bms_is_member(attrno, wholecols))
+ ereport(ERROR,
+ (errcode(ERRCODE_DUPLICATE_COLUMN),
+ errmsg("column \"%s\" specified more than once",
+ name),
+ parser_errposition(pstate, col->location)));
+ partialcols = bms_add_member(partialcols, attrno);
+ }
+
+ *attrnos = lappend_int(*attrnos, attrno);
+ }
+ }
+
+ return cols;
+}
+
+/*
+ * ExpandColumnRefStar()
+ * Transforms foo.* into a list of expressions or targetlist entries.
+ *
+ * This handles the case where '*' appears as the last or only item in a
+ * ColumnRef. The code is shared between the case of foo.* at the top level
+ * in a SELECT target list (where we want TargetEntry nodes in the result)
+ * and foo.* in a ROW() or VALUES() construct (where we want just bare
+ * expressions).
+ *
+ * The referenced columns are marked as requiring SELECT access.
+ */
+static List *
+ExpandColumnRefStar(ParseState *pstate, ColumnRef *cref,
+ bool make_target_entry)
+{
+ List *fields = cref->fields;
+ int numnames = list_length(fields);
+
+ if (numnames == 1)
+ {
+ /*
+ * Target item is a bare '*', expand all tables
+ *
+ * (e.g., SELECT * FROM emp, dept)
+ *
+ * Since the grammar only accepts bare '*' at top level of SELECT, we
+ * need not handle the make_target_entry==false case here.
+ */
+ Assert(make_target_entry);
+ return ExpandAllTables(pstate, cref->location);
+ }
+ else
+ {
+ /*
+ * Target item is relation.*, expand that table
+ *
+ * (e.g., SELECT emp.*, dname FROM emp, dept)
+ *
+ * Note: this code is a lot like transformColumnRef; it's tempting to
+ * call that instead and then replace the resulting whole-row Var with
+ * a list of Vars. However, that would leave us with the RTE's
+ * selectedCols bitmap showing the whole row as needing select
+ * permission, as well as the individual columns. That would be
+ * incorrect (since columns added later shouldn't need select
+ * permissions). We could try to remove the whole-row permission bit
+ * after the fact, but duplicating code is less messy.
+ */
+ char *nspname = NULL;
+ char *relname = NULL;
+ ParseNamespaceItem *nsitem = NULL;
+ int levels_up;
+ enum
+ {
+ CRSERR_NO_RTE,
+ CRSERR_WRONG_DB,
+ CRSERR_TOO_MANY
+ } crserr = CRSERR_NO_RTE;
+
+ /*
+ * Give the PreParseColumnRefHook, if any, first shot. If it returns
+ * non-null then we should use that expression.
+ */
+ if (pstate->p_pre_columnref_hook != NULL)
+ {
+ Node *node;
+
+ node = pstate->p_pre_columnref_hook(pstate, cref);
+ if (node != NULL)
+ return ExpandRowReference(pstate, node, make_target_entry);
+ }
+
+ switch (numnames)
+ {
+ case 2:
+ relname = strVal(linitial(fields));
+ nsitem = refnameNamespaceItem(pstate, nspname, relname,
+ cref->location,
+ &levels_up);
+ break;
+ case 3:
+ nspname = strVal(linitial(fields));
+ relname = strVal(lsecond(fields));
+ nsitem = refnameNamespaceItem(pstate, nspname, relname,
+ cref->location,
+ &levels_up);
+ break;
+ case 4:
+ {
+ char *catname = strVal(linitial(fields));
+
+ /*
+ * We check the catalog name and then ignore it.
+ */
+ if (strcmp(catname, get_database_name(MyDatabaseId)) != 0)
+ {
+ crserr = CRSERR_WRONG_DB;
+ break;
+ }
+ nspname = strVal(lsecond(fields));
+ relname = strVal(lthird(fields));
+ nsitem = refnameNamespaceItem(pstate, nspname, relname,
+ cref->location,
+ &levels_up);
+ break;
+ }
+ default:
+ crserr = CRSERR_TOO_MANY;
+ break;
+ }
+
+ /*
+ * Now give the PostParseColumnRefHook, if any, a chance. We cheat a
+ * bit by passing the RangeTblEntry, not a Var, as the planned
+ * translation. (A single Var wouldn't be strictly correct anyway.
+ * This convention allows hooks that really care to know what is
+ * happening. It might be better to pass the nsitem, but we'd have to
+ * promote that struct to a full-fledged Node type so that callees
+ * could identify its type.)
+ */
+ if (pstate->p_post_columnref_hook != NULL)
+ {
+ Node *node;
+
+ node = pstate->p_post_columnref_hook(pstate, cref,
+ (Node *) (nsitem ? nsitem->p_rte : NULL));
+ if (node != NULL)
+ {
+ if (nsitem != NULL)
+ ereport(ERROR,
+ (errcode(ERRCODE_AMBIGUOUS_COLUMN),
+ errmsg("column reference \"%s\" is ambiguous",
+ NameListToString(cref->fields)),
+ parser_errposition(pstate, cref->location)));
+ return ExpandRowReference(pstate, node, make_target_entry);
+ }
+ }
+
+ /*
+ * Throw error if no translation found.
+ */
+ if (nsitem == NULL)
+ {
+ switch (crserr)
+ {
+ case CRSERR_NO_RTE:
+ errorMissingRTE(pstate, makeRangeVar(nspname, relname,
+ cref->location));
+ break;
+ case CRSERR_WRONG_DB:
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cross-database references are not implemented: %s",
+ NameListToString(cref->fields)),
+ parser_errposition(pstate, cref->location)));
+ break;
+ case CRSERR_TOO_MANY:
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("improper qualified name (too many dotted names): %s",
+ NameListToString(cref->fields)),
+ parser_errposition(pstate, cref->location)));
+ break;
+ }
+ }
+
+ /*
+ * OK, expand the nsitem into fields.
+ */
+ return ExpandSingleTable(pstate, nsitem, levels_up, cref->location,
+ make_target_entry);
+ }
+}
+
+/*
+ * ExpandAllTables()
+ * Transforms '*' (in the target list) into a list of targetlist entries.
+ *
+ * tlist entries are generated for each relation visible for unqualified
+ * column name access. We do not consider qualified-name-only entries because
+ * that would include input tables of aliasless JOINs, NEW/OLD pseudo-entries,
+ * etc.
+ *
+ * The referenced relations/columns are marked as requiring SELECT access.
+ */
+static List *
+ExpandAllTables(ParseState *pstate, int location)
+{
+ List *target = NIL;
+ bool found_table = false;
+ ListCell *l;
+
+ foreach(l, pstate->p_namespace)
+ {
+ ParseNamespaceItem *nsitem = (ParseNamespaceItem *) lfirst(l);
+
+ /* Ignore table-only items */
+ if (!nsitem->p_cols_visible)
+ continue;
+ /* Should not have any lateral-only items when parsing targetlist */
+ Assert(!nsitem->p_lateral_only);
+ /* Remember we found a p_cols_visible item */
+ found_table = true;
+
+ target = list_concat(target,
+ expandNSItemAttrs(pstate,
+ nsitem,
+ 0,
+ location));
+ }
+
+ /*
+ * Check for "SELECT *;". We do it this way, rather than checking for
+ * target == NIL, because we want to allow SELECT * FROM a zero_column
+ * table.
+ */
+ if (!found_table)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("SELECT * with no tables specified is not valid"),
+ parser_errposition(pstate, location)));
+
+ return target;
+}
+
+/*
+ * ExpandIndirectionStar()
+ * Transforms foo.* into a list of expressions or targetlist entries.
+ *
+ * This handles the case where '*' appears as the last item in A_Indirection.
+ * The code is shared between the case of foo.* at the top level in a SELECT
+ * target list (where we want TargetEntry nodes in the result) and foo.* in
+ * a ROW() or VALUES() construct (where we want just bare expressions).
+ * For robustness, we use a separate "make_target_entry" flag to control
+ * this rather than relying on exprKind.
+ */
+static List *
+ExpandIndirectionStar(ParseState *pstate, A_Indirection *ind,
+ bool make_target_entry, ParseExprKind exprKind)
+{
+ Node *expr;
+
+ /* Strip off the '*' to create a reference to the rowtype object */
+ ind = copyObject(ind);
+ ind->indirection = list_truncate(ind->indirection,
+ list_length(ind->indirection) - 1);
+
+ /* And transform that */
+ expr = transformExpr(pstate, (Node *) ind, exprKind);
+
+ /* Expand the rowtype expression into individual fields */
+ return ExpandRowReference(pstate, expr, make_target_entry);
+}
+
+/*
+ * ExpandSingleTable()
+ * Transforms foo.* into a list of expressions or targetlist entries.
+ *
+ * This handles the case where foo has been determined to be a simple
+ * reference to an RTE, so we can just generate Vars for the expressions.
+ *
+ * The referenced columns are marked as requiring SELECT access.
+ */
+static List *
+ExpandSingleTable(ParseState *pstate, ParseNamespaceItem *nsitem,
+ int sublevels_up, int location, bool make_target_entry)
+{
+ if (make_target_entry)
+ {
+ /* expandNSItemAttrs handles permissions marking */
+ return expandNSItemAttrs(pstate, nsitem, sublevels_up, location);
+ }
+ else
+ {
+ RangeTblEntry *rte = nsitem->p_rte;
+ List *vars;
+ ListCell *l;
+
+ vars = expandNSItemVars(nsitem, sublevels_up, location, NULL);
+
+ /*
+ * Require read access to the table. This is normally redundant with
+ * the markVarForSelectPriv calls below, but not if the table has zero
+ * columns. We need not do anything if the nsitem is for a join: its
+ * component tables will have been marked ACL_SELECT when they were
+ * added to the rangetable. (This step changes things only for the
+ * target relation of UPDATE/DELETE, which cannot be under a join.)
+ */
+ if (rte->rtekind == RTE_RELATION)
+ rte->requiredPerms |= ACL_SELECT;
+
+ /* Require read access to each column */
+ foreach(l, vars)
+ {
+ Var *var = (Var *) lfirst(l);
+
+ markVarForSelectPriv(pstate, var);
+ }
+
+ return vars;
+ }
+}
+
+/*
+ * ExpandRowReference()
+ * Transforms foo.* into a list of expressions or targetlist entries.
+ *
+ * This handles the case where foo is an arbitrary expression of composite
+ * type.
+ */
+static List *
+ExpandRowReference(ParseState *pstate, Node *expr,
+ bool make_target_entry)
+{
+ List *result = NIL;
+ TupleDesc tupleDesc;
+ int numAttrs;
+ int i;
+
+ /*
+ * If the rowtype expression is a whole-row Var, we can expand the fields
+ * as simple Vars. Note: if the RTE is a relation, this case leaves us
+ * with the RTE's selectedCols bitmap showing the whole row as needing
+ * select permission, as well as the individual columns. However, we can
+ * only get here for weird notations like (table.*).*, so it's not worth
+ * trying to clean up --- arguably, the permissions marking is correct
+ * anyway for such cases.
+ */
+ if (IsA(expr, Var) &&
+ ((Var *) expr)->varattno == InvalidAttrNumber)
+ {
+ Var *var = (Var *) expr;
+ ParseNamespaceItem *nsitem;
+
+ nsitem = GetNSItemByRangeTablePosn(pstate, var->varno, var->varlevelsup);
+ return ExpandSingleTable(pstate, nsitem, var->varlevelsup, var->location, make_target_entry);
+ }
+
+ /*
+ * Otherwise we have to do it the hard way. Our current implementation is
+ * to generate multiple copies of the expression and do FieldSelects.
+ * (This can be pretty inefficient if the expression involves nontrivial
+ * computation :-(.)
+ *
+ * Verify it's a composite type, and get the tupdesc.
+ * get_expr_result_tupdesc() handles this conveniently.
+ *
+ * If it's a Var of type RECORD, we have to work even harder: we have to
+ * find what the Var refers to, and pass that to get_expr_result_tupdesc.
+ * That task is handled by expandRecordVariable().
+ */
+ if (IsA(expr, Var) &&
+ ((Var *) expr)->vartype == RECORDOID)
+ tupleDesc = expandRecordVariable(pstate, (Var *) expr, 0);
+ else
+ tupleDesc = get_expr_result_tupdesc(expr, false);
+ Assert(tupleDesc);
+
+ /* Generate a list of references to the individual fields */
+ numAttrs = tupleDesc->natts;
+ for (i = 0; i < numAttrs; i++)
+ {
+ Form_pg_attribute att = TupleDescAttr(tupleDesc, i);
+ FieldSelect *fselect;
+
+ if (att->attisdropped)
+ continue;
+
+ fselect = makeNode(FieldSelect);
+ fselect->arg = (Expr *) copyObject(expr);
+ fselect->fieldnum = i + 1;
+ fselect->resulttype = att->atttypid;
+ fselect->resulttypmod = att->atttypmod;
+ /* save attribute's collation for parse_collate.c */
+ fselect->resultcollid = att->attcollation;
+
+ if (make_target_entry)
+ {
+ /* add TargetEntry decoration */
+ TargetEntry *te;
+
+ te = makeTargetEntry((Expr *) fselect,
+ (AttrNumber) pstate->p_next_resno++,
+ pstrdup(NameStr(att->attname)),
+ false);
+ result = lappend(result, te);
+ }
+ else
+ result = lappend(result, fselect);
+ }
+
+ return result;
+}
+
+/*
+ * expandRecordVariable
+ * Get the tuple descriptor for a Var of type RECORD, if possible.
+ *
+ * Since no actual table or view column is allowed to have type RECORD, such
+ * a Var must refer to a JOIN or FUNCTION RTE or to a subquery output. We
+ * drill down to find the ultimate defining expression and attempt to infer
+ * the tupdesc from it. We ereport if we can't determine the tupdesc.
+ *
+ * levelsup is an extra offset to interpret the Var's varlevelsup correctly.
+ */
+TupleDesc
+expandRecordVariable(ParseState *pstate, Var *var, int levelsup)
+{
+ TupleDesc tupleDesc;
+ int netlevelsup;
+ RangeTblEntry *rte;
+ AttrNumber attnum;
+ Node *expr;
+
+ /* Check my caller didn't mess up */
+ Assert(IsA(var, Var));
+ Assert(var->vartype == RECORDOID);
+
+ /*
+ * Note: it's tempting to use GetNSItemByRangeTablePosn here so that we
+ * can use expandNSItemVars instead of expandRTE; but that does not work
+ * for some of the recursion cases below, where we have consed up a
+ * ParseState that lacks p_namespace data.
+ */
+ netlevelsup = var->varlevelsup + levelsup;
+ rte = GetRTEByRangeTablePosn(pstate, var->varno, netlevelsup);
+ attnum = var->varattno;
+
+ if (attnum == InvalidAttrNumber)
+ {
+ /* Whole-row reference to an RTE, so expand the known fields */
+ List *names,
+ *vars;
+ ListCell *lname,
+ *lvar;
+ int i;
+
+ expandRTE(rte, var->varno, 0, var->location, false,
+ &names, &vars);
+
+ tupleDesc = CreateTemplateTupleDesc(list_length(vars));
+ i = 1;
+ forboth(lname, names, lvar, vars)
+ {
+ char *label = strVal(lfirst(lname));
+ Node *varnode = (Node *) lfirst(lvar);
+
+ TupleDescInitEntry(tupleDesc, i,
+ label,
+ exprType(varnode),
+ exprTypmod(varnode),
+ 0);
+ TupleDescInitEntryCollation(tupleDesc, i,
+ exprCollation(varnode));
+ i++;
+ }
+ Assert(lname == NULL && lvar == NULL); /* lists same length? */
+
+ return tupleDesc;
+ }
+
+ expr = (Node *) var; /* default if we can't drill down */
+
+ switch (rte->rtekind)
+ {
+ case RTE_RELATION:
+ case RTE_VALUES:
+ case RTE_NAMEDTUPLESTORE:
+ case RTE_RESULT:
+
+ /*
+ * This case should not occur: a column of a table, values list,
+ * or ENR shouldn't have type RECORD. Fall through and fail (most
+ * likely) at the bottom.
+ */
+ break;
+ case RTE_SUBQUERY:
+ {
+ /* Subselect-in-FROM: examine sub-select's output expr */
+ TargetEntry *ste = get_tle_by_resno(rte->subquery->targetList,
+ attnum);
+
+ if (ste == NULL || ste->resjunk)
+ elog(ERROR, "subquery %s does not have attribute %d",
+ rte->eref->aliasname, attnum);
+ expr = (Node *) ste->expr;
+ if (IsA(expr, Var))
+ {
+ /*
+ * Recurse into the sub-select to see what its Var refers
+ * to. We have to build an additional level of ParseState
+ * to keep in step with varlevelsup in the subselect.
+ */
+ ParseState mypstate;
+
+ MemSet(&mypstate, 0, sizeof(mypstate));
+ mypstate.parentParseState = pstate;
+ mypstate.p_rtable = rte->subquery->rtable;
+ /* don't bother filling the rest of the fake pstate */
+
+ return expandRecordVariable(&mypstate, (Var *) expr, 0);
+ }
+ /* else fall through to inspect the expression */
+ }
+ break;
+ case RTE_JOIN:
+ /* Join RTE --- recursively inspect the alias variable */
+ Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
+ expr = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
+ Assert(expr != NULL);
+ /* We intentionally don't strip implicit coercions here */
+ if (IsA(expr, Var))
+ return expandRecordVariable(pstate, (Var *) expr, netlevelsup);
+ /* else fall through to inspect the expression */
+ break;
+ case RTE_FUNCTION:
+
+ /*
+ * We couldn't get here unless a function is declared with one of
+ * its result columns as RECORD, which is not allowed.
+ */
+ break;
+ case RTE_TABLEFUNC:
+
+ /*
+ * Table function cannot have columns with RECORD type.
+ */
+ break;
+ case RTE_CTE:
+ /* CTE reference: examine subquery's output expr */
+ if (!rte->self_reference)
+ {
+ CommonTableExpr *cte = GetCTEForRTE(pstate, rte, netlevelsup);
+ TargetEntry *ste;
+
+ ste = get_tle_by_resno(GetCTETargetList(cte), attnum);
+ if (ste == NULL || ste->resjunk)
+ elog(ERROR, "CTE %s does not have attribute %d",
+ rte->eref->aliasname, attnum);
+ expr = (Node *) ste->expr;
+ if (IsA(expr, Var))
+ {
+ /*
+ * Recurse into the CTE to see what its Var refers to. We
+ * have to build an additional level of ParseState to keep
+ * in step with varlevelsup in the CTE; furthermore it
+ * could be an outer CTE.
+ */
+ ParseState mypstate;
+ Index levelsup;
+
+ MemSet(&mypstate, 0, sizeof(mypstate));
+ /* this loop must work, since GetCTEForRTE did */
+ for (levelsup = 0;
+ levelsup < rte->ctelevelsup + netlevelsup;
+ levelsup++)
+ pstate = pstate->parentParseState;
+ mypstate.parentParseState = pstate;
+ mypstate.p_rtable = ((Query *) cte->ctequery)->rtable;
+ /* don't bother filling the rest of the fake pstate */
+
+ return expandRecordVariable(&mypstate, (Var *) expr, 0);
+ }
+ /* else fall through to inspect the expression */
+ }
+ break;
+ }
+
+ /*
+ * We now have an expression we can't expand any more, so see if
+ * get_expr_result_tupdesc() can do anything with it.
+ */
+ return get_expr_result_tupdesc(expr, false);
+}
+
+
+/*
+ * FigureColname -
+ * if the name of the resulting column is not specified in the target
+ * list, we have to guess a suitable name. The SQL spec provides some
+ * guidance, but not much...
+ *
+ * Note that the argument is the *untransformed* parse tree for the target
+ * item. This is a shade easier to work with than the transformed tree.
+ */
+char *
+FigureColname(Node *node)
+{
+ char *name = NULL;
+
+ (void) FigureColnameInternal(node, &name);
+ if (name != NULL)
+ return name;
+ /* default result if we can't guess anything */
+ return "?column?";
+}
+
+/*
+ * FigureIndexColname -
+ * choose the name for an expression column in an index
+ *
+ * This is actually just like FigureColname, except we return NULL if
+ * we can't pick a good name.
+ */
+char *
+FigureIndexColname(Node *node)
+{
+ char *name = NULL;
+
+ (void) FigureColnameInternal(node, &name);
+ return name;
+}
+
+/*
+ * FigureColnameInternal -
+ * internal workhorse for FigureColname
+ *
+ * Return value indicates strength of confidence in result:
+ * 0 - no information
+ * 1 - second-best name choice
+ * 2 - good name choice
+ * The return value is actually only used internally.
+ * If the result isn't zero, *name is set to the chosen name.
+ */
+static int
+FigureColnameInternal(Node *node, char **name)
+{
+ int strength = 0;
+
+ if (node == NULL)
+ return strength;
+
+ switch (nodeTag(node))
+ {
+ case T_ColumnRef:
+ {
+ char *fname = NULL;
+ ListCell *l;
+
+ /* find last field name, if any, ignoring "*" */
+ foreach(l, ((ColumnRef *) node)->fields)
+ {
+ Node *i = lfirst(l);
+
+ if (IsA(i, String))
+ fname = strVal(i);
+ }
+ if (fname)
+ {
+ *name = fname;
+ return 2;
+ }
+ }
+ break;
+ case T_A_Indirection:
+ {
+ A_Indirection *ind = (A_Indirection *) node;
+ char *fname = NULL;
+ ListCell *l;
+
+ /* find last field name, if any, ignoring "*" and subscripts */
+ foreach(l, ind->indirection)
+ {
+ Node *i = lfirst(l);
+
+ if (IsA(i, String))
+ fname = strVal(i);
+ }
+ if (fname)
+ {
+ *name = fname;
+ return 2;
+ }
+ return FigureColnameInternal(ind->arg, name);
+ }
+ break;
+ case T_FuncCall:
+ *name = strVal(llast(((FuncCall *) node)->funcname));
+ return 2;
+ case T_A_Expr:
+ if (((A_Expr *) node)->kind == AEXPR_NULLIF)
+ {
+ /* make nullif() act like a regular function */
+ *name = "nullif";
+ return 2;
+ }
+ break;
+ case T_TypeCast:
+ strength = FigureColnameInternal(((TypeCast *) node)->arg,
+ name);
+ if (strength <= 1)
+ {
+ if (((TypeCast *) node)->typeName != NULL)
+ {
+ *name = strVal(llast(((TypeCast *) node)->typeName->names));
+ return 1;
+ }
+ }
+ break;
+ case T_CollateClause:
+ return FigureColnameInternal(((CollateClause *) node)->arg, name);
+ case T_GroupingFunc:
+ /* make GROUPING() act like a regular function */
+ *name = "grouping";
+ return 2;
+ case T_SubLink:
+ switch (((SubLink *) node)->subLinkType)
+ {
+ case EXISTS_SUBLINK:
+ *name = "exists";
+ return 2;
+ case ARRAY_SUBLINK:
+ *name = "array";
+ return 2;
+ case EXPR_SUBLINK:
+ {
+ /* Get column name of the subquery's single target */
+ SubLink *sublink = (SubLink *) node;
+ Query *query = (Query *) sublink->subselect;
+
+ /*
+ * The subquery has probably already been transformed,
+ * but let's be careful and check that. (The reason
+ * we can see a transformed subquery here is that
+ * transformSubLink is lazy and modifies the SubLink
+ * node in-place.)
+ */
+ if (IsA(query, Query))
+ {
+ TargetEntry *te = (TargetEntry *) linitial(query->targetList);
+
+ if (te->resname)
+ {
+ *name = te->resname;
+ return 2;
+ }
+ }
+ }
+ break;
+ /* As with other operator-like nodes, these have no names */
+ case MULTIEXPR_SUBLINK:
+ case ALL_SUBLINK:
+ case ANY_SUBLINK:
+ case ROWCOMPARE_SUBLINK:
+ case CTE_SUBLINK:
+ break;
+ }
+ break;
+ case T_CaseExpr:
+ strength = FigureColnameInternal((Node *) ((CaseExpr *) node)->defresult,
+ name);
+ if (strength <= 1)
+ {
+ *name = "case";
+ return 1;
+ }
+ break;
+ case T_A_ArrayExpr:
+ /* make ARRAY[] act like a function */
+ *name = "array";
+ return 2;
+ case T_RowExpr:
+ /* make ROW() act like a function */
+ *name = "row";
+ return 2;
+ case T_CoalesceExpr:
+ /* make coalesce() act like a regular function */
+ *name = "coalesce";
+ return 2;
+ case T_MinMaxExpr:
+ /* make greatest/least act like a regular function */
+ switch (((MinMaxExpr *) node)->op)
+ {
+ case IS_GREATEST:
+ *name = "greatest";
+ return 2;
+ case IS_LEAST:
+ *name = "least";
+ return 2;
+ }
+ break;
+ case T_SQLValueFunction:
+ /* make these act like a function or variable */
+ switch (((SQLValueFunction *) node)->op)
+ {
+ case SVFOP_CURRENT_DATE:
+ *name = "current_date";
+ return 2;
+ case SVFOP_CURRENT_TIME:
+ case SVFOP_CURRENT_TIME_N:
+ *name = "current_time";
+ return 2;
+ case SVFOP_CURRENT_TIMESTAMP:
+ case SVFOP_CURRENT_TIMESTAMP_N:
+ *name = "current_timestamp";
+ return 2;
+ case SVFOP_LOCALTIME:
+ case SVFOP_LOCALTIME_N:
+ *name = "localtime";
+ return 2;
+ case SVFOP_LOCALTIMESTAMP:
+ case SVFOP_LOCALTIMESTAMP_N:
+ *name = "localtimestamp";
+ return 2;
+ case SVFOP_CURRENT_ROLE:
+ *name = "current_role";
+ return 2;
+ case SVFOP_CURRENT_USER:
+ *name = "current_user";
+ return 2;
+ case SVFOP_USER:
+ *name = "user";
+ return 2;
+ case SVFOP_SESSION_USER:
+ *name = "session_user";
+ return 2;
+ case SVFOP_CURRENT_CATALOG:
+ *name = "current_catalog";
+ return 2;
+ case SVFOP_CURRENT_SCHEMA:
+ *name = "current_schema";
+ return 2;
+ }
+ break;
+ case T_XmlExpr:
+ /* make SQL/XML functions act like a regular function */
+ switch (((XmlExpr *) node)->op)
+ {
+ case IS_XMLCONCAT:
+ *name = "xmlconcat";
+ return 2;
+ case IS_XMLELEMENT:
+ *name = "xmlelement";
+ return 2;
+ case IS_XMLFOREST:
+ *name = "xmlforest";
+ return 2;
+ case IS_XMLPARSE:
+ *name = "xmlparse";
+ return 2;
+ case IS_XMLPI:
+ *name = "xmlpi";
+ return 2;
+ case IS_XMLROOT:
+ *name = "xmlroot";
+ return 2;
+ case IS_XMLSERIALIZE:
+ *name = "xmlserialize";
+ return 2;
+ case IS_DOCUMENT:
+ /* nothing */
+ break;
+ }
+ break;
+ case T_XmlSerialize:
+ *name = "xmlserialize";
+ return 2;
+ default:
+ break;
+ }
+
+ return strength;
+}